U.S. patent application number 14/873552 was filed with the patent office on 2016-05-05 for method for detecting the presence of a nucleic acid in a sample.
The applicant listed for this patent is Gen-Probe Incorporated. Invention is credited to Kelly G. AMMANN, Ralph E. BURNS, Ernest V. HANSBERRY, Glenn A. HORNER, Cheryl A. JAKUB, John E. KLING, Donald J. NIEGLOS, Robert E. SCHNEIDER, Robert J. SMITH.
Application Number | 20160122808 14/873552 |
Document ID | / |
Family ID | 22181564 |
Filed Date | 2016-05-05 |
United States Patent
Application |
20160122808 |
Kind Code |
A1 |
AMMANN; Kelly G. ; et
al. |
May 5, 2016 |
METHOD FOR DETECTING THE PRESENCE OF A NUCLEIC ACID IN A SAMPLE
Abstract
An automated method for detecting the presence of a nucleic acid
in a sample, where the method is performed within a housing of a
self-contained, stand-alone analyzer. The method includes purifying
the nucleic acid after it has been immobilized on a
magnetically-responsive solid support. A pipette of the analyzer is
used to form a reaction mixture comprising the purified nucleic
acid and all reagents required to perform a nucleic acid
amplification. Amplification products are synthesized that include
a nucleotide sequence contained in the nucleic acid or the
complement of the nucleic acid. The amplification products are
exposed to a probe in a mixture, where the probe forms a hybrid
with one of the amplification products. The formation of the hybrid
in the mixture provides an indication of the presence of the
nucleic acid in the sample.
Inventors: |
AMMANN; Kelly G.; (Boulder,
CO) ; BURNS; Ralph E.; (Boulder, CO) ;
HANSBERRY; Ernest V.; (Blacksburg, VA) ; HORNER;
Glenn A.; (Boulder, CO) ; JAKUB; Cheryl A.;
(Bowling Green, KY) ; KLING; John E.; (Roswell,
NM) ; NIEGLOS; Donald J.; (San Miguel de Allende,
MX) ; SCHNEIDER; Robert E.; (Erie, CO) ;
SMITH; Robert J.; (Louisville, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Gen-Probe Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
22181564 |
Appl. No.: |
14/873552 |
Filed: |
October 2, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14284025 |
May 21, 2014 |
9150908 |
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14873552 |
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14024261 |
Sep 11, 2013 |
8883455 |
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14284025 |
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11931722 |
Oct 31, 2007 |
8569019 |
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14024261 |
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10946557 |
Sep 22, 2004 |
7560255 |
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11931722 |
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09985064 |
Nov 1, 2001 |
6890742 |
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10946557 |
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09303030 |
Apr 30, 1999 |
6335166 |
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09985064 |
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60083927 |
May 1, 1998 |
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Current U.S.
Class: |
435/6.11 |
Current CPC
Class: |
B03C 1/282 20130101;
B01L 2200/147 20130101; Y10T 436/2575 20150115; C12Q 1/6834
20130101; G01N 35/0098 20130101; Y10T 156/1105 20150115; Y10T
436/11 20150115; B01L 2300/1822 20130101; C12Q 2537/10 20130101;
Y10T 436/119163 20150115; G01N 2035/00356 20130101; B01L 7/52
20130101; B01F 9/0021 20130101; G01N 2035/0455 20130101; B01L
2300/1827 20130101; B03C 1/288 20130101; Y10T 436/114998 20150115;
B03C 1/30 20130101; Y10T 436/113332 20150115; B03C 2201/26
20130101; C12Q 1/6832 20130101; Y10T 29/53657 20150115; G01N
35/1065 20130101; C12Q 1/6813 20130101; G01N 35/0099 20130101; Y10T
156/1906 20150115; G01N 35/025 20130101; B01L 9/06 20130101; B01F
9/0014 20130101; Y10T 29/53843 20150115; B01L 7/5255 20130101; G01N
2035/0437 20130101; G01N 2035/00524 20130101; B01F 2009/0074
20130101; B01F 9/0001 20130101; Y10T 29/53683 20150115; G01N
2035/103 20130101; Y10T 436/111666 20150115 |
International
Class: |
C12Q 1/68 20060101
C12Q001/68 |
Claims
1. (canceled)
2. A method for detecting the presence of a nucleic acid in a
sample, the method comprising performing within a housing of a
self-contained, stand-alone analyzer the automated steps of: a)
contacting the sample with a solid support such that a complex
comprising the nucleic acid and the solid support is formed in the
sample, wherein the solid support comprises a
magnetically-responsive particle, and wherein the complex is
suspended in a fluid component of the sample; b) after step a),
moving one or more permanent magnets of the analzyer from a down
position to an up position relative to the sample, such that the
sample is subjected to at least one magnetic field when the one or
more magnets are in the up position, wherein the one or more
magnets have no substantial effect on the solid support when the
one or more magnets are in the down position; c) while the sample
is subjected to the at least one magnetic field, aspirating at
least a portion of the fluid component of the sample from the
complex; d) after step c), washing the solid support one or more
times with a wash buffer, thereby providing a purified form of the
nucleic acid; e) forming a reaction mixture with a pipette
assembly, wherein the reaction mixture comprises the purified form
of the nucleic acid and all reagents required to perform a nucleic
acid amplification; f) synthesizing amplification products in the
reaction mixture, each of the amplification products comprising a
nucleotide sequence contained in the nucleic acid or its
complement; g) exposing an amplification product that is one of the
amplification products synthesized in step f) to a probe having a
label, such that a hybrid comprising the probe and the
amplification product is formed in solution in a mixture containing
the probe and the amplification products; and h) in the mixture of
step g), detecting the label after formation of the hybrid, wherein
the formation of the hybrid in the mixture is an indication of the
presence of the nucleic acid in the sample.
3. The method of claim 2, further comprising, prior to step a), a
manual step of providing the sample and the reagents to the
analyzer, wherein the sample and the reagents are separately
provided to the analyzer.
4. The method of claim 2, wherein the complex formed in step a)
further comprises a capture probe hybridized to the nucleic
acid.
5. The method of claim 2, wherein the one or more magnets pivot
between the down position and the up position during step b).
6. The method of claim 2, wherein the portion of the fluid
component of the sample aspirated in step c) is aspirated from a
receptacle having an open top end and a closed bottom end.
7. The method of claim 2, wherein the fluid component is aspirated
through a tiplet in frictional engagement with an aspirator tube of
a fluid aspirator of the analyzer.
8. The method of claim 2, further comprising, prior to step c), an
automated step of sensing the level of the fluid component.
9. The method of claim 2, wherein the portion of the fluid
component aspirated in step c) is drawn through an aspirator tube
to a fluid waste container.
10. The method of claim 9, wherein the fluid waste container is
situated in a lower chassis of the analyzer beneath a processing
deck contained within the housing.
11. The method of claim 2, wherein the steps of the method are
performed in a single receptacle.
12. The method claim 11, wherein the receptacle is open-ended when
performing the steps of the method.
13. The method of claim 11, wherein the receptacle is a cylindrical
tube.
14. The method of claim 11, wherein the receptacle is one of a
plurality of integrally formed receptacles.
15. The method of claim 2, wherein the amplification products
formed in step f) comprise amplification products having the
nucleotide sequence contained in the nucleic acid and amplification
products having the nucleotide sequence contained in the complement
of the nucleic acid.
16. The method of claim 2, wherein the probe hybridizes with
specificity to the amplification product in step g), and wherein
the nucleic acid is from a disease-associated pathogen.
17. The method of claim 2, wherein the label is a fluorescent or
chemiluminescent label.
18. The method of claim 2, wherein step f) is performed within an
enclosure having a receptacle access opening, the receptacle access
opening being closed by a door of the enclosure during step f).
19. The method of claim 2, wherein the analyzer is controlled by a
computer controller that is integrally housed within the
analyzer.
20. The method of claim 2, wherein the steps of the method are
performed at multiple stations situated on a processing deck
contained within the housing.
21. The method of claim 2, wherein the housing remains closed when
performing the steps of the method.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is continuation of U.S. application Ser.
No. 14/284,025, filed May 21, 2014, now pending, which is a
continuation of U.S. application Ser. No. 11/931,722, filed Oct.
31, 2007, now U.S. Pat. No. 8,569,019, which is a continuation of
U.S. application Ser. No. 10/946,557, filed Sep. 22, 2004, now U.S.
Pat. No. 7,560,255, which is a continuation of U.S. application
Ser. No. 09/985,064, filed Nov. 1, 2001, now U.S. Pat. No.
6,890,742, which is a continuation of U.S. application Ser. No.
09/303,030, filed Apr. 30, 1999, now U.S. Pat. No. 6,335,166, which
claims the benefit of U.S. Provisional Application No. 60/083,927,
filed May 1, 1998, the contents of each of which applications is
hereby incorporated by reference herein in its entirety.
FIELD
[0002] The present invention relates to an automated method of
purifying, amplifying and detecting the presence of a nucleic acid
in a sample, where the method is performed within a housing of a
self-contained, stand-alone analyzer. The method is performed
without human intervention.
BACKGROUND
[0003] None of the references described or referred to herein are
admitted to be prior art to the claimed invention.
[0004] Diagnostic assays are widely used in clinical diagnosis and
health science research to detect or quantify the presence or
amount of biological antigens, cell abnormalities, disease states,
and disease-associated pathogens, including parasites, fungi,
bacteria and viruses present in a host organism or sample. Where a
diagnostic assay permits quantification, practitioners may be
better able to calculate the extent of infection or disease and to
determine the state of a disease over time. In general, diagnostic
assays are based either on the detection of antigens (immunoassays)
or nucleic acids (nucleic acid-based assays) belonging to an
organism or virus of interest.
[0005] Nucleic acid-based assays generally include several steps
leading to the detection or quantification of one or more target
nucleic acid sequences in a sample which are specific to the
organism or virus of interest. The targeted nucleic acid sequences
can also be specific to an identifiable group of organisms or
viruses, where the group is defined by at least one shared sequence
of nucleic acid that is common to all members of the group and is
specific to that group in the sample being assayed. The detection
of individual and groups of organisms and viruses using nucleic
acid-based methods is fully described by Kohne, U.S. Pat. No.
4,851,330, and Hogan, U.S. Pat. No. 5,541,308.
[0006] The first step in a nucleic acid-based assay is designing a
probe which exhibits specificity, under stringent hybridization
conditions, for a nucleic acid sequence belonging to the organism
or virus of interest. While nucleic acid-based assays can be
designed to detect either deoxyribonucleic acid (DNA) or
ribonucleic acid (RNA), ribosomal RNA (rRNA), or the gene encoding
rRNA (rDNA), is typically the preferred nucleic acid for detection
of a prokaryotic or eukaryotic organism in a sample. Ribosomal RNA
target sequences are preferred because of their relative abundance
in cells, and because rRNA contains regions of sequence variability
that can be exploited to design probes capable of distinguishing
between even closely related organisms. (Ribosomal RNA is the major
structural component of the ribosome, which is the situs of protein
synthesis in a cell.) Viruses, which do not contain rRNA, and
cellular changes are often best detected by targeting DNA, RNA, or
a messenger RNA (mRNA) sequence, which is a nucleic acid
intermediate used to synthesize a protein. When the focus of a
nucleic acid-based assay is the detection of a genetic abnormality,
then the probes are usually designed to detect identifiable changes
in the genetic code, such as the abnormal Philadelphia chromosome
associated with chronic myelocytic leukemia. See, e.g., Stephenson
et al., U.S. Pat. No. 4,681,840.
[0007] When performing a nucleic acid-based assay, preparation of
the sample is necessary to release and stabilize target nucleic
acids which may be present in the sample. Sample preparation can
also serve to eliminate nuclease activity and remove or inactivate
potential inhibitors of nucleic acid amplification (discussed
below) or detection of the target nucleic acids. See, e.g., Ryder
et al., U.S. Pat. No. 5,639,599, which discloses methods for
preparing nucleic acid for amplification, including the use of
complexing agents able to complex with ferric ions contributed by
lysed red blood cells. The method of sample preparation can vary
and will depend in part on the nature of the sample being processed
(e.g., blood, urine, stool, pus or sputum). When target nucleic
acids are being extracted from a white blood cell population
present in a diluted or undiluted whole blood sample, a
differential lysis procedure is generally followed. See, e.g.,
Ryder et al., European Patent Application No. 93304542.9 and
European Patent Publication No. 0547267. Differential lysis
procedures are well known in the art and are designed to
specifically isolate nucleic acids from white blood cells, while
limiting or eliminating the presence or activity of red blood cell
products, such as heme, which can interfere with nucleic acid
amplification or detection.
[0008] Before or after exposing the extracted nucleic acid to a
probe, the target nucleic acid can be immobilized by target-capture
means, either directly or indirectly, using a "capture probe" bound
to a substrate, such as a magnetic bead. Examples of target-capture
methodologies are described by Ranki et al., U.S. Pat. No.
4,486,539, and Stabinsky, U.S. Pat. No. 4,751,177. Target capture
probes are generally short sequences of nucleic acid (i.e.,
oligonucleotide) capable of hybridizing, under stringent
hybridization conditions, with a sequence of nucleic acid which
also contains the target sequence. Magnets in close proximity to
the reaction vessel are used to draw and hold the magnetic beads to
the side of the vessel. Once the target nucleic acid is thus
immobilized, the hybridized nucleic acid can be separated from
non-hybridized nucleic acid by aspirating fluid from the reaction
vessel and optionally performing one or more wash steps.
[0009] In most instances, it is desirable to amplify the target
sequence using any of several nucleic acid amplification procedures
which are well known in the art. Specifically, nucleic acid
amplification is the enzymatic synthesis of nucleic acid amplicons
(copies) which contain a sequence that is complementary to a
nucleic acid sequence being amplified. Examples of nucleic acid
amplification procedures practiced in the art include the
polymerase chain reaction (PCR), strand displacement amplification
(SDA), ligase chain reaction (LCR), and transcription-associated
amplification (TAA). Nucleic acid amplification is especially
beneficial when the amount of target sequence present in a sample
is very low. By amplifying the target sequences and detecting the
amplicon synthesized, the sensitivity of an assay can be vastly
improved, since fewer target sequences are needed at the beginning
of the assay to better ensure detection of nucleic acid in the
sample belonging to the organism or virus of interest.
[0010] Methods of nucleic acid amplification are thoroughly
described in the literature. PCR amplification, for instance, is
described by Mullis et al. in U.S. Pat. Nos. 4,683,195, 4,683,202
and 4,800,159, and in Methods in Enzymology, 155:335-350 (1987).
Examples of SDA can be found in Walker, PCR Methods and
Applications, 3:25-30 (1993), Walker et al. in Nucleic Acids Res.,
20:1691-1996 (1992) and Proc. Natl. Acad. Sci., 89:392-396 (1991).
LCR is described in U.S. Pat. Nos. 5,427,930 and 5,686,272. And
different TAA formats are provided in publications such as Burg et
al. in U.S. Pat. No. 5,437,990; Kacian et al. in U.S. Pat. Nos.
5,399,491 and 5,554,516; and Gingeras et al. in International
Application No. PCT/US87/01966 and International Publication No. WO
88/01302, and International Application No. PCT/US88/02108 and
International Publication No. WO 88/10315.
[0011] Detection of a targeted nucleic acid sequence requires the
use of a probe having a nucleotide base sequence which is
substantially complementary to the targeted sequence or,
alternatively, its amplicon. Under selective assay conditions, the
probe will hybridize to the targeted sequence or its amplicon in a
manner permitting a practitioner to detect the presence of the
targeted sequence in a sample. Effective probes are designed to
prevent non-specific hybridization with any nucleic acid sequence
which will interfere with detecting the presence of the targeted
sequence. Probes may include a label capable of detection, where
the label is, for example, a radiolabel, fluorescent dye, biotin,
enzyme or chemiluminescent compound. Chemiluminescent compounds
include acridinium esters which can be used in a hybridization
protection assay (HPA) and then detected with a luminometer.
Examples of chemiluminescent compounds and methods of labeling
probes with chemiluminescent compounds can be found in Arnold et
al., U.S. Pat. Nos. 4,950,613, 5,185,439 and 5,585,481; and
Campbell et al., U.S. Pat. No. 4,946,958.
[0012] HPA is a detection method based on differential hydrolysis
which permits specific detection of the acridinium ester-labeled
probe hybridized to the target sequence or amplicon thereof. HPA is
described in detail by Arnold et al. in U.S. Pat. Nos. 5,283,174
and 5,639,604. This detection format permits hybridized probe to be
distinguished from non-hybridized probe in solution and includes
both a hybridization step and a selection step. In the
hybridization step, an excess of acridinium ester-labeled probe is
added to the reaction vessel and permitted to anneal to the target
sequence or its amplicon. Following the hybridization step, label
associated with unhybridized probe is rendered non-chemiluminescent
in the selection step by the addition of an alkaline reagent. The
alkaline reagent specifically hydrolyzes only that acridinium ester
label associated with unhybridized probe, leaving the acridinium
ester of the probe:target hybrid intact and detectable.
Chemiluminescence from the acridinium ester of the hybridized probe
can then be measured using a luminometer and signal is expressed in
relative light units (RLU).
[0013] After the nucleic acid-based assay is run, and to avoid
possible contamination of subsequent amplification reactions, the
reaction mixture can be treated with a deactivating reagent which
destroys nucleic acids and related amplification products in the
reaction vessel. Such reagents can include oxidants, reductants and
reactive chemicals which modify the primary chemical structure of a
nucleic acid. These reagents operate by rendering nucleic acids
inert towards an amplification reaction, whether the nucleic acid
is RNA or DNA. Examples of such chemical agents include solutions
of sodium hypochlorite (bleach), solutions of potassium
permanganate, formic acid, hydrazine, dimethyl sulfate and similar
compounds. More details of a deactivation protocol can be found in
Dattagupta et al., U.S. Pat. No. 5,612,200.
[0014] When performed manually, the complexity and shear number of
processing steps associated with a nucleic acid-based assay
introduce opportunities for practitioner-error, exposure to
pathogens, and cross-contamination between assays. Following a
manual format, the practitioner must safely and conveniently
juxtapose the test samples, reagents, waste containers, assay
receptacles, pipette tips, aspirator device, dispenser device, and
magnetic rack for performing target-capture, while being especially
careful not to confuse racks, test samples, assay receptacles, and
associated tips, or to knock over any tubes, tips, containers, or
instruments. In addition, the practitioner must carefully perform
aspirating and dispensing steps with hand-held, non-fixed
instruments in a manner requiring precise execution to avoid
undesirable contact between assay receptacles, aerosol formation,
or aspiration of magnetic particles or other substrates used in a
target-capture assay. As a further precaution, the magnetic field
in a manually performed target-capture assay is often applied to
only one side of the assay receptacle so that fluids can be
aspirated through a pipette tip inserted along the opposite side of
the assay receptacle. Although applying a magnetic field to only
one side of the assay receptacle is a less efficient means for
performing a target capture assay, it is designed to prevent
magnetic particles from being unnecessarily aspirated as a result
of practitioner inaccuracies.
[0015] A need exists for an automated diagnostic analyzer which
addresses many of the concerns associated with manual approaches to
performing nucleic acid-based assays. In particular, significant
advantages can be realized by automating the various process steps
of a nucleic acid-based assay, including greatly reducing the risk
of user-error, pathogen exposure, contamination, and spillage,
while significantly increasing through-put volume. Automating the
steps of a nucleic acid-based assay will also reduce the amount
training required for practitioners and virtually eliminate sources
of physical injury attributable to high-volume manual
applications.
SUMMARY
[0016] The above-described needs are addressed by an automated
clinical analyzer constructed and operated in accordance with
aspects of the present invention. In general, the automated
clinical analyzer integrates and coordinates the operation of
various automated stations, or modules, involved in performing one
or more assays on a plurality of reaction mixtures contained in
reaction receptacles. The analyzer is preferably a self-contained,
stand alone unit. Assay specimen materials and reaction
receptacles, as well as the various solutions, reagents, and other
materials used in performing the assays are preferably stored
within the analyzer, as are the waste products generated when
assays are performed.
[0017] The analyzer includes a computer controller which runs
analyzer-controlling and assay-scheduling software to coordinate
operation of the stations of the analyzer and movement of each
reaction receptacle through the analyzer.
[0018] Reaction receptacles can be loaded in an input queue which
sequentially presents each receptacle at a pick-up position to be
retrieved by a transport mechanism, which automatically transports
the reaction receptacles between the stations of the analyzer.
[0019] Specimen containers are carried on a first ring assembly,
and disposable pipette tips are carried on a second ring assembly.
Containers of target capture reagent, including a suspension of
solid support material, are carried on an inner rotatable assembly
constructed and arranged to selectively agitate the containers or
present the containers for access by the probe of an automatic
robotic pipette system. Reaction mixtures, including fluid specimen
material and target capture reagent, are prepared by the pipette
system within each reaction receptacle.
[0020] The analyzer further includes receptacle mixers for mixing
the contents of a receptacle placed therein. The mixer may be in
fluid communication with fluid containers and may include
dispensers for dispensing one or more fluids into the receptacle.
One or more incubators carry multiple receptacles in a
temperature-controlled chamber and permit individual receptacles to
be automatically placed into and removed from the chamber. Magnetic
separation wash stations automatically perform a magnetic
separation wash procedure on the contents of a receptacle placed in
the station.
[0021] In the preferred method of operation, assay results may be
ascertained by the amount of light emitted from a receptacle at the
conclusion of the appropriate preparation steps. Accordingly, the
analyzer includes a luminometer for detecting and/or quantifying
the amount of light emitted by the contents of the reaction
receptacle. A deactivation queue may be provided to deactivate the
contents of a reaction receptacle placed therein at the conclusion
of the assay.
[0022] Reaction receptacles can be independently transported
between stations by the transport mechanism, and the stations can
be operated in parallel to perform different assay procedures
simultaneously on different reaction receptacles, thereby
facilitating efficient, high through-put operation of the analyzer.
Moreover, the present invention facilitates arranging the various
stations associated with a nucleic acid-based assay onto a single,
contained platform, thereby achieving efficient space
utilization.
[0023] Other objects, features, and characteristics of the present
invention, including the methods of operation and the function and
interrelation of the elements of structure, will become more
apparent upon consideration of the following description and the
appended claims, with reference to the accompanying drawings, all
of which form a part of this disclosure, wherein like reference
numerals designate corresponding parts in the various figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a perspective view of an automated nucleic
acid-based diagnostic analyzer according to the present
invention;
[0025] FIG. 2 is a perspective view of the structural frame of the
analyzer of the present invention;
[0026] FIG. 3 is a plan view of a portion of the assay processing
deck of the analyzer of the present invention;
[0027] FIG. 4 is an exploded perspective view of the assay
processing deck;
[0028] FIG. 5 is a plan view of a specimen ring and a pipette tip
wheel of the assay processing deck of the analyzer of the present
invention;
[0029] FIG. 6 is a perspective view showing the specimen ring and
the pipette tip wheel;
[0030] FIG. 6A is a partial cross-sectional view along the line
6A-6A in FIG. 5;
[0031] FIG. 7 is a perspective view of a multi-axis mixer of the
processing deck of the analyzer of the present invention;
[0032] FIG. 8 is a plan view of the multi-axis mixer;
[0033] FIG. 9 is a side elevation of the multi-axis mixer;
[0034] FIG. 10 is a plan view of the multi-axis mixer with
container holders and a turntable cover removed therefrom;
[0035] FIG. 11 is a cross-sectional view of the multi-axis mixer
taken in the direction 11-11 in FIG. 10;
[0036] FIG. 12 is a perspective view of a drive assembly of the
multi-axis mixer;
[0037] FIG. 13 is a perspective view of a transport mechanism of
the processing deck of the analyzer of the present invention;
[0038] FIG. 14 is a perspective view of a manipulating hook
mounting plate and a manipulating hook actuating mechanism of the
transport mechanism, with the manipulating hook member engaged with
a reaction receptacle and in a retracted position;
[0039] FIG. 15 is the same as FIG. 14, except with the manipulating
hook member in the extended position;
[0040] FIG. 16 is an exploded perspective view of the transport
mechanism;
[0041] FIG. 17 is a side-elevation of a temperature ramping station
of the processing deck of the analyzer of the present
invention;
[0042] FIG. 18 is a front-elevation of the temperature ramping
station;
[0043] FIG. 19 is a perspective view of a rotary incubator of the
processing deck of the analyzer of the present invention;
[0044] FIG. 20 is an exploded view of a portion of a housing and
access opening closure mechanisms according to a first embodiment
of the rotary incubator;
[0045] FIG. 21 is a partial view of a skewed disk linear mixer of
the rotary incubator, shown engaged with a reaction receptacle
employed in a preferred mode of operation of the analyzer of the
present invention;
[0046] FIG. 22 is an exploded perspective view of the first
embodiment of the rotary incubator;
[0047] FIG. 23 is a perspective view of the rotary incubator
according to a second embodiment thereof;
[0048] FIG. 23A is an exploded perspective view of the second
embodiment of the rotary incubator;
[0049] FIG. 23B is a partial exploded perspective view of an access
opening closure mechanism of the second embodiment of the rotary
incubator;
[0050] FIG. 23C is an exploded view of a receptacle carrier
carousel of the second embodiment of the rotary incubator;
[0051] FIG. 24 is a perspective view of a magnetic separation wash
station of the processing deck of the present invention with a side
plate thereof removed;
[0052] FIG. 25 is a partial transverse cross-section of the
magnetic separation wash station;
[0053] FIG. 25A is a partial transverse cross-section of a tip of
an aspirating tube of the magnetic separation wash station with a
contamination-limiting tiplet carried on the end thereof;
[0054] FIG. 26 is an exploded perspective view of a receptacle
carrier unit, an orbital mixer assembly, and a divider plate of the
magnetic separation wash station;
[0055] FIG. 27 is a partial cross-sectional view of a wash buffer
dispenser nozzle, an aspirator tube with a contamination-limiting
tiplet engaged with an end thereof, and a receptacle carrier unit
of the magnetic separation wash station, showing a multi-tube unit
reaction receptacle employed in a preferred mode of operation of
the analyzer carried in the receptacle carrier unit and the
aspirator tube and contamination-limiting tiplet inserted into a
receptacle vessel of the multi-tube unit;
[0056] FIG. 28 is a partial cross-sectional view of the wash buffer
dispenser nozzle, the aspirator tube, and the receptacle carrier
unit of the magnetic separation wash station, showing the
multi-tube unit carried in the receptacle carrier unit and the
aspirator tube engaging the contamination-limiting tiplet held in a
contamination-limiting element holding structure of the multi-tube
unit;
[0057] FIGS. 29A-29D show a partial cross-section of a first
embodiment of a tiplet stripping hole of a tiplet stripping plate
of the magnetic separation wash station and a tiplet stripping
operation using the tiplet stripping hole;
[0058] FIGS. 30A-30D show a partial cross-section of a second
embodiment of a tiplet stripping hole and a tiplet stripping
operation using the tiplet stripping hole;
[0059] FIG. 31A is a plan view of a third embodiment of a tiplet
stripping hole of a tiplet stripping plate of the magnetic
separation wash station;
[0060] FIGS. 31B-31C show a partial cross-section of the third
embodiment of the tiplet stripping hole and a tiplet stripping
operation using the tiplet;
[0061] FIG. 32 is a perspective view of an orbital mixer with a
front plate thereof removed;
[0062] FIG. 33 is an exploded view of the orbital mixer of the
processing deck of the analyzer of the present invention;
[0063] FIG. 34 is a top-plan view of the orbital mixer;
[0064] FIG. 35 is a top perspective view of a reagent cooling bay
of the processing deck of the analyzer of the present
invention;
[0065] FIG. 36 is a top perspective view of a reagent cooling bay
with the container tray removed therefrom;
[0066] FIG. 37 is a bottom plan view of the reagent cooling
bay;
[0067] FIG. 38 is an exploded view of the reagent cooling bay;
[0068] FIG. 39 is a top perspective view of a modular container
tray of the reagent cooling bay;
[0069] FIG. 40 is a perspective view of a first embodiment of a
luminometer of the processing deck of the analyzer of the present
invention;
[0070] FIG. 41 is a partial exploded perspective view of the
luminometer of the first embodiment;
[0071] FIG. 42A is a partial perspective view of a receptacle
transport mechanism of the first embodiment of the luminometer;
[0072] FIG. 42B is an end view of the receptacle transport
mechanism of the first embodiment of the luminometer;
[0073] FIG. 42C is a top view of the receptacle transport mechanism
of the first embodiment of the luminometer;
[0074] FIG. 43 is a break away perspective view of a second
embodiment of the luminometer of the present invention;
[0075] FIG. 44 is an exploded perspective view of a multi-tube unit
door assembly for the luminometer of the second embodiment;
[0076] FIG. 45 is an exploded perspective view of a shutter
assembly for a photosensor aperture for the luminometer of the
second embodiment;
[0077] FIG. 45A is a perspective view of an aperture plate of the
shutter assembly of the luminometer of the second embodiment;
[0078] FIG. 46 is a perspective view of a receptacle vessel
positioner assembly of the luminometer of the second embodiment,
including a receptacle vessel positioner disposed within a
receptacle vessel positioner frame;
[0079] FIG. 47 is a perspective view of the receptacle vessel
positioner;
[0080] FIG. 48 is a side elevation of the receptacle vessel
positioner assembly;
[0081] FIG. 49 is a perspective view showing the receptacle vessel
positioner of the receptacle vessel positioner assembly operatively
engaging a multi-tube unit employed in a preferred mode of
operation of the analyzer;
[0082] FIG. 50 is a perspective view of a multi-tube unit transport
mechanism of the luminometer of the second embodiment;
[0083] FIG. 51 is a partial perspective view showing a multi-tube
unit transport and drive screw of the multi-tube unit transport
mechanism of the luminometer;
[0084] FIG. 52 is a perspective view of a lower chassis of the
analyzer of the present invention;
[0085] FIG. 53 is a perspective view of a right-side drawer of the
lower chassis;
[0086] FIG. 54 is a perspective view of a left-side drawer of the
lower chassis;
[0087] FIG. 55 is a perspective view of a specimen tube tray
employed in a preferred mode of operation of the analyzer of the
present invention;
[0088] FIG. 56 is a top plan view of the specimen tube tray;
[0089] FIG. 57 is a partial cross-section of the specimen tube tray
through line "57-57" in FIG. 55;
[0090] FIG. 58 is a perspective view of a multi-tube unit employed
in a preferred mode of operation of the analyzer of the present
invention;
[0091] FIG. 59 is a side elevation of a contact-limiting pipette
tiplet employed in a preferred mode of operation of the analyzer of
the present invention and carried on the multi-tube unit shown in
FIG. 58; and
[0092] FIG. 60 is an enlarged bottom view of a portion of the
multi-tube unit, viewed in the direction of arrow "60" in FIG.
58.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Analyzer Overview
[0093] An automated diagnostic analyzer according to the present
invention is designated generally by reference number 50 in FIGS. 1
and 2. Analyzer 50 includes a housing 60 built over an internal
frame structure 62, preferably made of steel. The analyzer 50 is
preferably supported on caster wheels 64 structurally mounted to
the frame structure 62 so as to make the analyzer movable.
[0094] The various stations involved in performing an automated
assay and the assay specimens are housed within housing 60. In
addition, the various solutions, reagents, and other materials used
in performing the assays are preferably stored within the housing
60, as are the waste products generated when assays are performed
with the analyzer 50.
[0095] Housing 60 includes a test receptacle loading opening 68,
which is shown in FIG. 1 to be disposed in a forwardly facing panel
of the housing 60, but could as well be located in other panels of
the housing 60. A pipette door 70 having a view window 72 and a
carousel door 74 having a view window 76 are disposed above a
generally horizontal work surface 66. A forwardly protruding
arcuate panel 78 accommodates a specimen carousel, which will be
described below. A flip-up arcuate specimen door 80 is pivotally
attached to the housing so as to be vertically pivotal with respect
to arcuate panel 78 so as to provide access to a forward portion of
the specimen carousel behind the panel 78. Sensors indicate when
the doors are closed, and the specimen door 80, the carousel door
74, and the pipette door 70 are locked during analyzer operation.
The locking mechanism for each door preferably consists of a hook
attached to a DC rotary solenoid (rated for continuous duty) with a
spring return. Preferred rotary solenoids are available from Lucas
Control Systems, of Vandalia, Ohio, model numbers L-2670-034 and
L-1094-034.
[0096] An extension portion 102, preferably made of a transparent
or translucent material, extends above the top portion of housing
60 so as to provide vertical clearance for moving components within
the housing 60.
[0097] The assays are performed primarily on a processing deck 200,
which is the general location of the various assay stations of the
analyzer 50 described below. For simplicity of the illustration,
the processing deck 200 is shown in FIG. 2 without any of the assay
stations mounted thereon. The processing deck 200 comprises a datum
plate 82 to which the various stations are directly or indirectly
mounted. Datum plate 82 preferably comprises a machined aluminum
plate. The processing deck 200, also known as the chemistry deck,
separates the interior of the housing into the chemistry area, or
upper chassis, above the datum plate 82 and the storage areas, or
lower chassis 1100, located below the datum plate 82.
[0098] A number of fans and louvers are preferably provided in the
upper chassis portion of the housing 60 to create air circulation
throughout the upper chassis to avoid excessive temperatures in the
upper chassis.
[0099] As the analyzer 50 of the present invention is computer
controlled, the analyzer 50 includes a computer controller,
schematically represented as box 1000 in FIG. 2, which runs
high-level analyzer-controlling software known as the "assay
manager program". The assay manager program includes a scheduler
routine which monitors and controls test specimen movement through
the chemistry deck 200.
[0100] The computer controller 1000 which controls the analyzer 50
may include a stand-alone computer system including a CPU,
keyboard, monitor, and may optionally include a printer device. A
portable cart may also be provided for storing and supporting the
various computer components. Alternately, the computer hardware for
running the analyzer-controlling software may be integrally housed
within the housing 60 of the analyzer 50.
[0101] Low level analyzer control, such as control of electric
motors and heaters used throughout the analyzer 50 and monitoring
of fluid levels within bulk fluid and waste fluid containers, is
performed by an embedded controller, preferably comprising a
Motorola 68332 microprocessor. Stepper motors used throughout the
analyzer are also preferably controlled by preprogrammed,
off-the-shelf, microprocessor chips available from E-M
Technologies, Bala Cynwyd, Pa.
[0102] The processing deck 200 is shown schematically in FIGS. 3
and 4. FIG. 3 represents a schematic plan view of a portion of the
processing deck 200, and FIG. 4 represents a schematic perspective
view of the processing deck. The datum plate 82 forms the
foundation of the processing deck 200 on which all stations are
directly or indirectly attached.
[0103] Processing deck 200 includes a reaction receptacle input
queue 150 which extends from opening 68 in front of housing 60. A
plurality of reaction receptacles are loaded in a stacked fashion
in the input queue 150. The purpose of the input queue is to hold a
prescribed number of reaction receptacles and to sequentially
present them at a pick-up position to be retrieved by a transport
mechanism (described below). A reflective sensor at the pick-up
position verifies the presence of a receptacle at that position.
The input queue also includes a device for counting the number of
receptacles resident therein at any given time.
[0104] A reaction receptacle shuttle assembly (not shown) within
the queue moves the receptacles along a receptacle advance path
toward the pick-up position. Optical sensors indicate when the
shuttle assembly is in its home and fully extended positions. The
queue includes a drawer which may be pulled out for loading the
receptacles therein. Before the drawer is opened, however, it must
be unlocked and the shuttle must disengage from the receptacle
advance path. When the drawer is again closed, it is locked and the
shuttle engages the receptacles and moves them toward the pick-up
position. Optical sensors indicate when the drawer is closed and
when the shuttle has engaged a receptacle. As each receptacle is
removed from the pick-up position by the transport mechanism, the
receptacle shuttle advances the receptacles one receptacle-width,
so that the next receptacle is in the pick-up position.
[0105] The reaction receptacles are preferably integrally formed
linear arrays of test tubes and known as multi-tube units, or MTUs.
The preferred reaction receptacles (MTUs) will be described in more
detail below.
[0106] A first ring assembly, which in the preferred embodiment
comprises a specimen ring 250, is mounted on a pivoting jig plate
130 at a distance above the datum plate 82. Specimen ring 250 is
generally circular and preferably holds up to nine specimen trays
300 in an annular fluid container carrier portion thereof, and each
of the specimen trays preferably holds 20 specimen-containing
containers, or test tubes 320. The specimen ring 250 is constructed
and arranged to be rotatable about a first generally vertical axis
of rotation and delivers the specimen tubes 320 to a specimen
pipette assembly 450, preferably an automated robotic pipette
system. The forward portion of specimen ring 250 is accessible
through the flip-up carousel door 80 provided in housing 60 so that
trays 300 of test tubes 320 can be easily loaded onto the specimen
ring 250 and unloaded from the specimen ring. Specimen ring 250 is
driven by a motor, as will be described in more detail below.
[0107] A second ring assembly, which in the preferred embodiment
comprises a pipette tip wheel 350, is located in an interior
portion of the specimen ring 250, so that at least a portion of the
outer perimeter of the pipette tip wheel 350 is disposed radially
inwardly of the inner periphery of the ring 250. Pipette tip wheel
350 carries thereon a plurality of commercially available packages
of pipette tips. Pipette tip wheel 350 is motor driven to rotate
independently of specimen ring 250 about a second axis of rotation
that is generally parallel to the first axis of rotation of the
specimen ring 250.
[0108] An inner rotatable assembly constructed and arranged to
carry a plurality of fluid containers is provided at an interior
portion of the pipette tip wheel 350. In the preferred embodiment,
the inner rotatable assembly comprises a multi-axis mixer 400
located radially inside the pipette tip wheel 350 (i.e., the second
ring assembly) and specimen ring 250 (i.e., the first ring
assembly). The multi-axis mixer 400 includes a rotating turntable
414 that is rotatable about a third axis of rotation that is
generally parallel to the first and second axes of rotation and on
which are mounted four independently and eccentrically rotating
container holders 406. Each of the container holders 406 receives a
container, preferably in the form of a plastic bottle, containing a
fluid suspension of magnetic particles with immobilized
polynucleotides and polynucleotide capture probes. Each container
holder 406 is generally cylindrical in shape and includes an axis
of symmetry, or axis of rotation. The multi-axis mixer 400 rotates
each of the containers eccentrically with respect to the center of
the holder 406, while simultaneously rotating the turntable 414
about its center so as to provide substantially constant agitation
of the containers to maintain the magnetic particles in suspension
within the fluid.
[0109] The specimen pipette assembly, or robot, 450 is mounted to
the frame structure 62 (see FIG. 2) in a position above the
specimen ring 250 and pipette tip wheel 350. The specimen pipette
assembly 450 includes a pipette unit 456 having a tubular probe 457
mounted on a gantry assembly to provide X, Y, Z motion.
Specifically, the pipette unit 456 is linearly movable in the
Y-direction along a track 458 formed in a lateral rail 454, and the
lateral rail 454 is longitudinally movable in the X-direction along
a longitudinal track 452. The pipette unit 456 provides vertical,
or Z-axis motion of the probe 457. Drive mechanisms within the
specimen pipette assembly 450 position the pipette unit 456 to the
correct X, Y, Z coordinates within the analyzer 50 to pipette
fluids, to wash the probe 457 of the pipette unit 456, to discard a
protective tip from an end of the probe 457 of the pipette unit
456, or to stow the pipette unit 456 during periods of nonuse,
e.g., in a "home" position. Each axis of the specimen pipette
assembly 450 is driven by a stepper motor in a known and
conventional manner.
[0110] The pipette assembly is preferably an off-the-shelf product.
Presently preferred is the Robotic Sample Processor, model number
RSP9000, available from Cavro Inc. of Sunnyvale, Calif. This model
includes a single gantry arm.
[0111] The specimen pipette assembly 450 is preferably coupled to a
syringe pump (not shown) (the Cavro XP 3000 has been used) and a DC
driven diaphragm system fluid wash pump (not shown). The syringe
pump of the specimen pipette assembly 450 is preferably mounted to
the internal frame structure 62 within the housing 60 of the
analyzer 50 at a position above the left-hand side of the chemistry
deck 200 and is connected to pipette unit 456 by suitable tubing
(not shown) or other conduit structures.
[0112] A specimen preparation opening 252 is provided in the jig
plate 130, so that the specimen pipette assembly 450 can access a
reaction receptacle 160 in the input queue 150 located below the
jig plate 130.
[0113] The specimen pipette assembly 450 of the analyzer 50 engages
specimen tubes 320 carried on the specimen ring 250 through
openings 140, 142 of an elevated cover plate 138 and engages
pipette tips carried on the pipette tip wheel 350 near the back
portions of the specimen ring 250 and pipette tip wheel 350,
respectively. Accordingly, an operator can have access to the
forward portions of specimen ring 250 and pipette tip wheel 350
through the carousel door opening 80 during operation of the
analyzer without interfering with pipetting procedures.
[0114] A tip wash/disposal station 340 is disposed adjacent to the
specimen ring 250 on the jig plate 130. Station 340 includes a tip
disposal tube 342 and a wash station basin 346. During specimen
preparation, the pipette unit 456 of the specimen pipette assembly
450 can move into position above the wash station basin 346 where
the tubular probe 457 can be washed by pumping distilled water
through the probe 457, the basin of the wash station 346 being
connected, preferably by a flexible hose (not shown), to a liquid
waste container in the lower chassis 1100.
[0115] The tip disposal tube 342 comprises an upstanding tubular
member. During specimen transfer from a specimen tube 320 to a
reaction receptacle 160, an elongated pipette tip is frictionally
secured onto the end of the tubular probe 457 of the pipette unit
456, so that specimen material does not come into contact with the
tubular probe 457 of the pipette unit 456 when material is drawn
from a specimen tube 320 and into the elongated pipette tip. After
a specimen has been transferred from a specimen tube 320, it is
critical that the pipette tip used in transferring that specimen
not be used again for another unrelated specimen. Therefore, after
specimen transfer, the pipette unit 456 moves to a position above
the tip disposal tube 342 and ejects the used, disposable pipette
tip into the tip disposal tube 342 which is connected to one of the
solid waste containers carried in the lower chassis 1100.
[0116] An elongated pipette tip is preferably also frictionally
secured to the probe 457 for transferring target capture reagent
from containers carried on the multi-axis mixer 400 to a reaction
receptacle 160. Following reagent transfer, the pipette tip is
discarded.
[0117] As noted, the specimen ring 250, the pipette tip wheel 350,
and the multi-axis mixer 400 are preferably mounted on a hinged jig
plate 130 (see FIGS. 5 and 6) supported above the datum plate 82.
The jig plate 130 is hinged at a back end 132 thereof (see FIG. 6)
so that the plate, and the ring 250, the wheel 350, and the mixer
400 mounted thereon, can be pivoted upwardly to permit access to
the area of the chemistry deck below the jig plate.
[0118] A first, or right-side, transport mechanism 500 is mounted
on the datum plate 82 below the jig plate 130 and specimen ring 250
on generally the same plane as the input queue 150. Transport
mechanism 500 includes a rotating main body portion 504 defining a
receptacle carrier assembly and an extendible manipulating hook 506
mounted within the main body 504 and extendible and retractable
with respect thereto by means of a powered hook member drive
assembly. Each of the reaction receptacles 160 preferably includes
manipulating structure that can be engaged by the extendible
manipulating hook 506, so that the transport mechanism 500 can
engage and manipulate a reaction receptacle 160 and move it from
one location on the processing deck 200 to another as the reaction
receptacle is sequentially moved from one station to another during
the performance of an assay within the reaction receptacle 160.
[0119] A second, or left-side, transport mechanism 502, of
substantially identical construction as first transport mechanism
500, is also included on the processing deck 200.
[0120] A plurality of receptacle parking stations 210 are also
located below the jig plate 130. The parking stations 210, as their
name implies, are structures for holding specimen-containing
reaction receptacles until the assay performing stations of the
processing deck 200 of the analyzer 50 are ready to accept the
reaction receptacles. The reaction receptacles are retrieved from
and inserted into the parking stations 210 as necessary by the
transport mechanism 500.
[0121] A right-side orbital mixer 550 is attached to the datum
plate 82 and receives reaction receptacles 160 inserted therein by
the right-side transport mechanism 500. The orbital mixer is
provided to mix the contents of the reaction receptacle 160. After
mixing is complete, the right-side transport mechanism 500 removes
the reaction receptacle from the right-side orbital mixer 550 and
moves it to another location in the processing deck.
[0122] A number of incubators 600, 602, 604, 606, of substantially
identical construction are provided. Incubators 600, 602, 604, and
606 are preferably rotary incubators. Although the particular assay
to be performed and the desired throughput will determine the
desired number of necessary incubators, four incubators are
preferably provided in the analyzer 50.
[0123] As will be described in more detail below, each incubator
(600, 602, 604, 606) has a first, and may also have a second,
receptacle access opening through which a transport mechanism 500
or 502 can insert a reaction receptacle 160 into the incubator or
retrieve a reaction receptacle 160 from the incubator. Within each
incubator (600, 602, 604, 606) is a rotating receptacle carrier
carousel which holds a plurality of reaction receptacles 160 within
individual receptacle stations while the receptacles are being
incubated. For the nucleic acid-based diagnostic assay preferably
performed on the analyzer 50 of the present invention, first rotary
incubator 600 is a target capture and annealing incubator, second
rotary incubator 602 is an active temperature and pre-read
cool-down incubator (also known as an "AT incubator"), third rotary
incubator 604 is an amplification incubator, and fourth rotary
incubator 606 is a hybridization protection assay incubator. The
construction, function, and role of the incubators in the overall
performance of the assay will be described in more detail
below.
[0124] The processing deck 200 preferably also includes a plurality
of temperature ramping stations 700. Two such stations 700 are
shown attached to the datum plate 82 between incubators 602 and 604
in FIG. 3. Additional ramping stations may be disposed at other
locations on the processing deck 200 where they will be accessible
by one of the transport mechanisms 500, 502.
[0125] A reaction receptacle 160 may be placed into or removed from
a temperature ramping station 700 by either transport mechanism 500
or 502. Each ramping station 700 either raises or lowers the
temperature of the reaction receptacle and its contents to a
desired temperature before the receptacle is placed into an
incubator or another temperature sensitive station. By bringing the
reaction receptacle and its contents to a desired temperature
before inserting it into one of the incubators (600, 602, 604,
606), temperature fluctuations within the incubator are
minimized.
[0126] The processing deck 200 also includes magnetic separation
wash stations 800 for performing a magnetic separation wash
procedure. Each magnetic separation wash station 800 can
accommodate and perform a wash procedure on one reaction receptacle
160 at a time. Therefore, to achieve the desired throughput, five
magnetic separation wash stations 800 working in parallel are
preferred. Receptacles 160 are inserted into and removed from the
magnetic separation wash stations 800 by the left-side transport
mechanism 502.
[0127] A reagent cooling bay 900 is attached to the datum plate 82
roughly between the incubators 604 and 606. Reagent cooling bay 900
comprises a carousel structure having a plurality of container
receptacles for holding bottles of temperature sensitive reagents.
The carousel resides within a cooled housing structure having a lid
with pipette-access holes formed therein.
[0128] A second, or left-side, orbital mixer 552, substantially
identical to right-side orbital mixer 550, is disposed between
incubators 606 and 604. The left-side orbital mixer 552 includes
dispenser nozzles and lines for dispensing fluids into the reaction
receptacle resident within the left-side orbital mixer 552.
[0129] A reagent pipette assembly, or robot, 470 includes a double
gantry structure attached to the frame structure 62 (see FIG. 2)
and is disposed generally above the incubators 604 and 606 on the
left-hand side of the processing deck 200. Specifically, reagent
pipette assembly 470 includes pipette units 480 and 482. Pipette
unit 480 includes a tubular probe 481 and is mounted for linear
movement, generally in the X-direction, along track 474 of lateral
rail 476, and pipette unit 482, including a tubular probe 483, is
also mounted for linear motion, generally in the X-direction, along
track 484 of lateral rail 478. Lateral rails 476 and 478 can
translate, generally in a Y-direction, along the longitudinal track
472. Each pipette unit 480, 482 provides independent vertical, or
Z-axis, motion of the respective probe 481, 483. Drive mechanisms
within the assembly 470 position the pipette units 480, 482 to the
correct X, Y, Z coordinates within the analyzer 50 to pipette
fluids, to wash the tubular probes 481, 483 of the respective
pipette units 480, 482, or to stow the pipette units 480, 482
during periods of nonuse, e.g., in "home" positions. Each axis of
the pipette assembly 470 is driven by a stepper motor.
[0130] The reagent pipette assembly 470 is preferably an
off-the-shelf product. The presently preferred unit is the Cavro
Robotic Sample Processor, model RSP9000, with two gantry arms.
[0131] The pipette units 480, 482 of the reagent pipette assembly
470 are each preferably coupled to a respective syringe pump (not
shown) (the Cavro XP 3000 has been used) and a DC driven diaphragm
system fluid wash pump. The syringe pumps of the reagent pipette
assembly 470 are preferably mounted to the internal frame structure
62 within the housing 60 of the analyzer 50 at a position above the
left-hand side of the chemistry deck 200 and are connected to the
respective pipette units 480, 482 by suitable tubing (not shown) or
other conduit structures.
[0132] Each pipette unit 480, 482 preferably includes capacitive
level sensing capability. Capacitive level sensing, which is
generally known in the medical instrumentation arts, employs
capacitance changes when the dielectric of a capacitor, formed by
the pipette unit as one plate of the capacitor and the structure
and hardware surrounding a container engaged by the pipette unit as
the opposite plate, changes from air to fluid to sense when the
probe of the pipette unit has penetrated fluid within a container.
By ascertaining the vertical position of the probe of the pipette
unit, which may be known by monitoring the stepper motor which
drives vertical movement of the pipette unit, the level of the
fluid within the container engaged by the pipette unit may be
determined.
[0133] Pipette unit 480 transfers reagents from the reagent cooling
bay 900 into reaction receptacles disposed within the incubator 606
or the orbital mixer 552, and pipette unit 482 transfers reagent
materials from the reagent cooling bay 900 into reaction
receptacles disposed within the amplification incubator 604 or the
orbital mixer 552.
[0134] The pipette units 480, 482 use capacitive level sensing to
ascertain fluid level within a container and submerge only a small
portion of the end of the probe of the pipette unit to pipette
fluid from the container. Pipette units 480, 482 preferably descend
as fluid is pipetted into the respective tubular probes 481, 483 to
keep the end of the probes submerged to a constant depth. After
drawing reagent into the tubular probe of the pipette unit 480 or
482, the pipette units create a minimum travel air gap of 10 .mu.l
the end of the respective probe 481 or 483 to ensure no drips from
the end of the probe as the pipette unit is moved to another
location above the chemistry deck 200.
[0135] The results of the assay preferably performed in the
analyzer 50 of the present invention are ascertained by the amount
of chemiluminescence, or light, emitted from a receptacle vessel
162 at the conclusion of the appropriate preparation steps.
Specifically, the results of the assay are determined from the
amount of light emitted by label associated with hybridized
polynucleotide probe at the conclusion of the assay. Accordingly,
the processing deck 200 includes a luminometer 950 for detecting
and/or quantifying the amount of light emitted by the contents of
the reaction receptacle. Briefly, the luminometer 950 comprises a
housing through which a reaction receptacle travels under the
influence of a transport mechanism, a photomultiplier tube, and
associated electronics. Various luminometer embodiments will be
described in detail below.
[0136] The processing deck 200 also preferably includes a
deactivation queue 750. The assay performed in the analyzer 50
involves the isolation and amplification of nucleic acids belonging
to at least one organism or cell of interest. Therefore, it is
desirable to deactivate the contents of the reaction receptacle
160, typically by dispensing a bleach-based reagent into the
reaction receptacle 160 at the conclusion of the assay. This
deactivation occurs within the deactivation queue 750.
[0137] Following deactivation, the deactivated contents of the
reaction receptacle 160 are stored in one of the liquid waste
containers of the lower chassis 1100 and the used reaction
receptacle is discarded into a dedicated solid waste container
within the lower chassis 1100. The reaction receptacle is
preferably not reused.
Analyzer Operation
[0138] The operation of the analyzer 50, and the construction,
cooperation, and interaction of the stations, components, and
modules described above will be explained by describing the
operation of the analyzer 50 on a single test specimen in the
performance of one type of assay which may be performed with
analyzer 50. Other diagnostic assays, which require the use of one
or more of the stations, components, and modules described herein,
may also be performed with the analyzer 50. The description herein
of a particular assay procedure is merely for the purpose of
illustrating the operation and interaction of the various stations,
components, and modules of the analyzer 50 and is not intended to
be limiting. Those skilled in the art of diagnostic testing will
appreciate that a variety of chemical and biological assays can be
performed in an automated fashion with the analyzer 50 of the
present invention.
[0139] The analyzer 50 is initially configured for an assay run by
loading bulk fluids into the bulk fluid storage bay of the lower
chassis 1100 and connecting the bulk fluid containers to the
appropriate hoses (not shown).
[0140] The analyzer is preferably powered up in a sequential
process, initially powering the stations, or modules, that will be
needed early in the process, and subsequently powering the stations
that will not be needed until later in the process. This serves to
conserve energy and also avoids large power surges that would
accompany full analyzer power-up and which could trip circuit
breakers. The analyzer also employs a "sleep" mode during periods
of nonuse. During sleep mode, a minimal amount of power is supplied
to the analyzer, again to avoid large surges necessary to power-up
an analyzer from complete shut-down.
[0141] A number of reaction receptacles 160, preferably in the form
of plastic, integrally formed multiple-tube units (MTUs), which are
described in more detail below, are loaded through opening 68 into
the input queue 150. Henceforth, the reaction receptacles 160 will
be referred to as MTUs, consistent with the preferred manner of
using the analyzer 50.
[0142] The reaction receptacle shuttle assembly (not shown) within
the input queue 150 moves the MTUs 160 from the loading opening 68
to the pick-up position at the end of the queue 150. The right-side
transport mechanism 500 takes an MTU 160 from the end of the queue
150 and moves to a bar code reader (not shown) to read the unique
bar code label on that MTU which identifies that MTU. From the bar
code reader, the MTU is moved to an available specimen transfer
station 255 below opening 252.
Multiple Tube Units
[0143] As shown in FIG. 58, an MTU 160 comprises a plurality of
individual receptacle vessels 162, preferably five. The receptacle
vessels 162, preferably in the form of cylindrical tubes with open
top ends and closed bottom ends, are connected to one another by a
connecting rib structure 164 which defines a downwardly facing
shoulder extending longitudinally along either side of the MTU
160.
[0144] The MTU 160 is preferably formed from injection molded
polypropylene. The most preferred polypropylene is sold by Montell
Polyolefins, of Wilmington, Del., product number PD701NW. The
Montell material is used because it is readily moldable, chemically
compatible with the preferred mode of operation of the analyzer 50,
and has a limited number of static discharge events which can
interfere with accurate detection or quantification of
chemiluminescence.
[0145] An arcuate shield structure 169 is provided at one end of
the MTU 160. An MTU manipulating structure 166 to be engaged by one
of the transport mechanisms 500, 502 extends from the shield
structure 169. MTU manipulating structure 166 comprises a laterally
extending plate 168 extending from shield structure 169 with a
vertically extending piece 167 on the opposite end of the plate
168. A gusset wall 165 extends downwardly from lateral plate 168
between shield structure 169 and vertical piece 167.
[0146] As shown in FIG. 60 the shield structure 169 and vertical
piece 167 have mutually facing convex surfaces. The MTU 160 is
engaged by the transport mechanisms 500, 502 and other components,
as will be described below, by moving an engaging member laterally
(in the direction "A") into the space between the shield structure
169 and the vertical piece 167. The convex surfaces of the shield
structure 169 and vertical piece 167 provide for wider points of
entry for an engaging member undergoing a lateral relative motion
into the space. The convex surfaces of the vertical piece 167 and
shield structure 169 include raised portions 171, 172,
respectively, formed at central portions thereof. The purpose of
portions 171, 172 will be described below.
[0147] A label-receiving structure 174 having a flat
label-receiving surface 175 is provided on an end of the MTU 160
opposite the shield structure 169 and MTU manipulating structure
166. Labels, such as scannable bar codes, can be placed on the
surface 175 to provide identifying and instructional information on
the MTU 160.
[0148] The MTU 160 preferably includes tiplet holding structures
176 adjacent the open mouth of each respective receptacle vessel
162. Each tiplet holding structure 176 provides a cylindrical
orifice within which is received a contact-limiting tiplet 170. The
construction and function of the tiplet 170 will be described
below. Each holding structure 176 is constructed and arranged to
frictionally receive a tiplet 170 in a manner that prevents the
tiplet 170 from falling out of the holding structure 176 when the
MTU 160 is inverted, but permits the tiplet 170 to be removed from
the holding structure 176 when engaged by a pipette.
[0149] As shown in FIG. 59, the tiplet 170 comprises a generally
cylindrical structure having a peripheral rim flange 177 and an
upper collar 178 of generally larger diameter than a lower portion
179 of the tiplet 170. The tiplet 170 is preferably formed from
conductive polypropylene. When the tiplet 170 is inserted into an
orifice of a holding structure 176, the flange 177 contacts the top
of structure 176 and the collar 178 provides a snug but releasable
interference fit between the tiplet 170 and the holding structure
176.
[0150] An axially extending through-hole 180 passes through the
tiplet. Hole 180 includes an outwardly flared end 181 at the top of
the tiplet 170 which facilitates insertion of a pipette tubular
probe (not shown) into the tiplet 170. Two annular ridges 183 line
the inner wall of hole 180. Ridges 183 provide an interference
friction fit between the tiplet 170 and a tubular probe inserted
into the tiplet 170.
[0151] The bottom end of the tiplet 170 preferably includes a
beveled portion 182. When tiplet 170 is used on the end of an
aspirator that is inserted to the bottom of a reaction receptacle,
such as a receptacle vessel 162 of an MTU 160, the beveled portion
182 prevents a vacuum from forming between the end of the tiplet
170 and the bottom of the reaction receptacle vessel.
Lower Chassis
[0152] An embodiment of the lower chassis of the present invention
is shown in FIGS. 52-54. The lower chassis 1100 includes a steel
frame 1101 with a black polyurethane powder coat, a pull-out drip
tray 1102 disposed below the chassis, a right-side drawer 1104, and
a left-side drawer 1106. The left-side drawer 1106 is actually
centrally disposed within the lower chassis 1100. The far left-side
of the lower chassis 1100 houses various power supply system
components and other analyzer mechanisms such as, for example,
seven syringe pumps 1152 mounted on a mounting platform 1154, a
vacuum pump 1162 preferably mounted on the floor of the lower
chassis 1100 on vibration isolators (not shown), a power supply
unit 1156, a power filter 1158, and fans 1160.
[0153] A different syringe pump 1152 is designated for each of the
five magnetic separation wash stations 800, one is designated for
the left-side orbital mixer 552, and one is designated for the
deactivation queue 750. Although syringe pumps are preferred,
peristaltic pumps may be used as an alternative.
[0154] The vacuum pump 1162 services each of the magnetic
separation wash stations 800 and the deactivation queue 750. The
preferred rating of the vacuum pump is 5.3-6.5 cfm at 0'' Hg and
4.2-5.2 cfm at 5'' Hg. A preferred vacuum pump is available from
Thomas Industries, Inc. of Sheboygan, Wisconsin, as model number
2750CGHI60. A capacitor 1172 is sold in conjunction with the pump
1162.
[0155] The power supply unit 1156 is preferably an ASTEC, model
number VS 1-B5-B7-03, available from ASTEC America, Inc., of
Carlsbad, Calif. Power supply unit 1156 accepts 220 volts ranging
from 50-60 Hz, i.e., power from a typical 220 volt wall outlet.
Power filter 1158 is preferably a Corcom model 20MV1 filter,
available from Corcom, Inc. of Libertyville, Ill. Fans 1160 are
preferably Whisper XLDC fans available from Comair Rotron, of San
Ysidro, Calif. Each fan is powered by a 24 VDC motor and has a 75
cfm output. As shown in FIG. 52, the fans 1160 are preferably
disposed proximate a left-side outer wall of the lower chassis
1100. The fans 1160 are preferably directed outwardly to draw air
through the lower chassis from the right-side thereof to the
left-side thereof, and thus, to draw excess heat out of the lower
chassis.
[0156] Other power supply system components are housed in the back
left-hand side of the lower chassis 1100, including a power switch
1174, preferably an Eaton circuit breaker switch 2-pole, series
JA/S, available from the Cutler-Hammer Division of Eaton
Corporation of Cleveland, Ohio, and a power inlet module 1176 at
which a power cord (not shown) for connecting the analyzer 50 to an
external power source is connected. The power supply system of the
analyzer 50 also includes a terminal block (not shown), for
attaching thereto a plurality of electrical terminals, a solid
state switch (not shown), which is preferably a Crydom Series 1,
model number D2425, available from Cal Switch, Carson City, Calif.,
for switching between different circuits, and an RS232 9-pin
connector port for connecting the analyzer 50 to the external
computer controller 1000.
[0157] The right-side drawer and left-side drawer bays are
preferably closed behind one or two doors (not shown) in front of
the analyzer, which is/are preferably locked by the assay manager
program during operation of the analyzer. Microswitches are
preferably provided to verify door-closed status. The far left bay
is covered by a front panel. End panels are provided on opposite
ends of the lower chassis to enclose the chassis.
[0158] Four leveler feet 1180 extend down from the four corners of
the chassis 1100. The leveler feet 1180 include threaded shafts
with pads at the lower ends thereof. When the analyzer is in a
desired location, the feet 1180 can be lowered until the pads
engage the floor to level and stabilize the analyzer. The feet can
also be raised to permit the analyzer to be moved on its
casters.
[0159] Bulk fluids typically contained in the containers of the
lower chassis 1100 may include wash buffer (for washing immobilized
target), distilled water (for washing fixed pipette tips),
diagnostic testing reagents, silicone oil (used as a floating fluid
for layering over test reagents and specimen), and a bleach-based
reagent (used for sample deactivation).
[0160] The right-side drawer 1104 is shown in detail in FIG. 53.
The right-side drawer 1104 includes a box-like drawer structure
with a front drawer handle 1105. Although drawer handle 1105 is
shown as a conventional pull-type drawer handle, in the preferred
embodiment of the analyzer 50, handle 1105 is a T-handle latch,
such as those available from Southco, Inc. of Concordville, Pa. The
drawer 1104 is mounted in the lower chassis on slide brackets (not
shown) so that the drawer 1104 can be pulled into and out of the
lower chassis. A sensor (not shown) is preferably provided for
verifying that the drawer 1104 is closed. The front portion of the
drawer includes bottle receptacles 1122 for holding bottle 1128
(shown in FIG. 52), which is a dedicated pipette wash
waste-containing bottle, and bottle 1130 (also shown in FIG. 52),
which is a dedicated waste bottle for containing waste from a
magnetic wash, target-capture procedure. Bottle 1130 is preferably
evacuated.
[0161] The analyzer 50 will not begin processing assays if any of
the bottles required in the lower chassis 1100 are missing. Bottle
receptacles 1122 preferably include bottle-present sensors (not
shown) to verify the presence of a bottle in each receptacle 1122.
The bottle-present sensors are preferably diffuse reflective type
optical sensors available from SUNX/Ramco Electric, Inc., of West
Des Moines, Iowa, model EX-14A.
[0162] Right-side drawer 1104 further includes a waste bin 1108 for
holding therein spent MTUs and specimen tips. Waste bin 1108 is an
open box structure with a sensor mount 1112 at a top portion
thereof for mounting thereon a sensor, preferably a 24 VDC
Opto-diffuse reflector switch (not shown), for detecting whether
the waste bin 1108 is full. Another diffuse reflector type optical
sensor (not shown) is positioned within right-side drawer 1104 to
verify that the waste bin 1108 is in place. Again, diffuse
reflective type optical sensors available from SUNX/Ramco Electric,
Inc., of West Des Moines, Iowa, model EX-14A, are preferred.
[0163] A deflector 1110 extends obliquely from a side of the waste
bin 1108. Deflector 1110 is disposed directly below a chute through
which spent MTUs are dropped into the waste bin 1108 and deflects
the dropped MTUs toward the middle of the waste bin 1108 to avoid
MTU pile-ups in a corner of the waste bin 1108. Deflector 1110 is
preferably pivotally mounted so that it can pivot upwardly to a
substantially vertical position so that when a waste bag, which
lines the waste bin 1108 and covers the deflector 1110, is removed
from the waste bin 1108, the deflector 1110 will pivot upwardly
with the bag as it is pulled out and therefore will not rip the
bag.
[0164] A printed circuit board (not shown) and cover 1114 can be
mounted to the front of the waste bin 1108. Sensor mounts 1116 and
1117 are also mounted to the front of waste bin 1108. Sensors 1118
and 1119 are mounted on sensor mount 1116, and sensors 1120 and
1121 mounted on sensor mount 1117. Sensors 1118, 1119, 1120, and
1121 are preferably DC capacitive proximity sensors. The upper
sensors 1118, 1119 indicate when the bottles 1128 and 1130 are
full, and the bottom sensors 1120, 1121 indicate when the bottles
are empty. Sensors 1118-1121 are preferably those available from
Stedham Electronics Corporation of Reno, Nev., model number
C2D45AN1-P, which were chosen because their relatively flat
physical profile requires less space within the tight confines of
the lower chassis 1100 and because the Stedham sensors provide the
desired sensing distance range of 3-20 mm.
[0165] The analyzer 50 will preferably not begin performing any
assays if the assay manager program detects that any of the waste
fluid containers in the right-side drawer 1104 are not initially
empty.
[0166] The capacitive proximity sensors 1118-1121 and the
bottle-present, waste-bin-present, and waste-bin-full optical
sensors of the right-side drawer 1104 are connected to the printed
circuit board (not shown) behind cover 1114, and the printed
circuit board is connected to the embedded controller of the
analyzer 50.
[0167] Because the right-side drawer 1104 cannot be pulled
completely out of the lower chassis 1100, it is necessary to be
able to pull the waste bin 1108 forward so as to permit access to
the waste bin for installing and removing a waste bag liner. For
this purpose, a handle 1126 is mounted to the front of the waste
bin 1108 and teflon strips 1124 are disposed on the bottom floor of
the right-side drawer 1104 to facilitate forward and backward
sliding of the waste bin 1108 in the drawer 1104 when bottles 1128
and 1130 are removed.
[0168] Details of the left-side drawer 1106 are shown in FIG. 54.
Left-side drawer 1106 includes a box-like structure with a front
mounted handle 1107 and is mounted within the lower chassis 1100 on
slide brackets (not shown). Although handle 1107 is shown as a
conventional pull-type drawer handle, in the preferred embodiment
of the analyzer 50, handle 1107 is a T-handle latch, such as those
available from Southco, Inc. of Concordville, Pa. A sensor is
provided for verifying that the left-side drawer 1106 is
closed.
[0169] Left-side drawer 1106 includes a tiplet waste bin 1134 with
a mounting structure 1135 for mounting thereon a
tiplet-waste-bin-full sensor (not shown). A
tiplet-waste-bin-present sensor is preferably provided in the
left-side drawer 1106 to verify that the tiplet waste bin 1134 is
properly installed. Diffuse reflective type optical sensors
available from SUNX/Ramco Electric, Inc., of West Des Moines, Iowa,
model EX-14A, are preferred for both the tiplet-waste-bin-full
sensor and the tiplet-waste-bin-present sensor.
[0170] Bundling structures 1132 are provided for securing and
bundling various tubing and/or wires (not shown) within the lower
chassis 1100. The bundling structures preferably used are Energy
Chain Systems manufactured and sold by Igus, Inc. of East
Providence, R.I.
[0171] A printed circuit board 1182 is mounted behind a panel 1184
which is located behind the tiplet waste bin 1134. A solenoid valve
mounting panel 1186 is located below the tiplet waste bin 1134.
[0172] Left-side drawer 1106 includes a forward container-holding
structure for holding therein six similarly sized bottles. The
container structure includes divider walls 1153, 1155, 1157, and
1159 and container blocks 1151 having a curved bottle-conforming
front edge, which together define six container-holding areas.
Lower sensors 1148 and upper sensors 1150 (six of each) are mounted
on the divider walls 1155, 1157, and 1159. The upper and lower
sensors 1148, 1150 are preferably DC capacitive proximity sensors
(preferably sensors available from Stedham Electronics Corporation
of Reno, Nev., model number C2D45AN1-P, chosen for their flat
profile and sensing range). The upper sensors 1150 indicate when
the bottles held in the container structure are full, and the lower
sensors 1148 indicate when the bottles are empty. In the preferred
arrangement, the left two bottles 1146 contain a detecting agent
("Detect I"), the middle two bottles 1168 contain silicone oil, and
the right two bottles 1170 contain another detecting agent ("Detect
II").
[0173] Bottle-present sensors (not shown) are preferably provided
in each of the container-holding areas defined by the container
blocks 1151 and the dividing walls 1153, 1155, 1157, and 1159 to
verify the presence of bottles in each container-holding area. The
bottle-present sensors are preferably diffuse reflective type
optical sensors available from SUNX/Ramco Electric, Inc., of West
Des Moines, Iowa, model EX-14A.
[0174] A large centrally located container receptacle 1164 holds a
bottle 1140 (shown in FIG. 52), preferably containing deionized
water. Container receptacles 1166 (only one is visible in FIG. 54)
hold bottles 1142 and 1144 (also shown in FIG. 52) preferably
containing a wash buffer solution. A dividing wall 1143 between the
receptacle 1164 and 1166 has mounted thereon sensors, such as
sensor 1141, for monitoring the fluid level in the bottles 1140,
1142, and 1144. The sensors, such as sensor 1141, are preferably DC
capacitive proximity sensors (preferably sensors available from
Stedham Electronics Corporation of Reno, Nev., model number
C2D45AN1-P).
[0175] Container receptacles 1164 and 1166 preferably include
bottle-present sensors (not shown) for verifying that bottles are
properly positioned in their respective receptacles. The
bottle-present sensors are preferably diffuse reflective type
optical sensors available from SUNX/Ramco Electric, Inc., of West
Des Moines, Iowa, model EX-14A.
[0176] The analyzer 50 will not begin performing any assays if the
assay manager program determines that any of the bulk-fluid
containers in the left-side drawer 1106 are initially empty.
[0177] The capacitive proximity fluid level sensors, the various
bottle-present sensors, the tiplet-waste-bin-full sensor, and the
tiplet-waste-bin-present sensors are all connected to the printed
circuit board 1182, and the printed circuit board 1182 is connected
to the embedded controller of the analyzer 50.
[0178] Four solenoid valves (not shown) are mounted below the
solenoid valve mounting panel 1186. The solenoid valves connect
bulk fluid bottles where fluids are stored in pairs of bottles,
i.e., the bottles 1140, 1142 containing wash buffer solution, the
two bottles 1146 containing the "Detect I" agent, the two bottles
1168 containing oil, and the two bottles 1170 containing the
"Detect II" agent. The solenoid valves, in response to signals from
the respective capacitive proximity sensors, switch bottles from
which fluid is being drawing when one of the two bottles containing
the same fluid is empty. In addition, the solenoid valves may
switch bottles after a prescribed number of tests are performed.
The preferred solenoid valves are teflon solenoid valves available
from Beco Manufacturing Co., Inc. of Laguna Hills, Calif., model
numbers S313W2DFRT and M223W2DFRLT. The two different model numbers
correspond to solenoid valves adapted for use with two different
tube sizes. Teflon solenoid valves are preferred because they are
less likely to contaminate fluids flowing through the valves and
the valves are not damaged by corrosive fluids flowing through
them.
[0179] Bottle 1136 (see FIG. 52) is a vacuum trap held in a vacuum
trap bracket 1137, and bottle 1138 contains a deactivating agent,
such as bleach-containing reagent. Again, bottle-present sensors
are preferably provided to verify the presence of bottles 1136 and
1138.
[0180] A hand-held bar code scanner 1190 may be provided in the
lower chassis 1100 for scanning information provided on scannable
container labels into the assay manager program. Scanner 1190 is
connected by a cord to printed circuit board 1182 of the left-side
drawer 1106 and is preferably stowed on a bracket (not show)
mounted on dividing wall 1143. Scanners available from Symbol
Technologies, Inc., of Holtsville, N.Y., series LS2100, are
preferred.
Specimen Ring and Specimen Tube Trays
[0181] Specimens are contained in the specimen tubes 320, and the
tubes 320 are loaded into the tube trays 300 outside the analyzer
50. The trays 300 carrying the specimen tubes 320 are placed onto
the specimen ring 250 through the access opening provided by
opening the flip-up carousel door 80.
[0182] Referring to FIGS. 5 and 6, the first ring assembly, or
specimen ring, 250 is formed of milled, unhardened aluminum and
includes a raised ring structure defining an annular trough 251
about the outer periphery of ring 250 with a plurality of raised,
radially extending dividers 254 extending through trough 251.
Preferably, nine dividers 254 divide the trough 251 into nine
arcuate specimen tube tray-receiving wells 256. The trough 251 and
wells 256 define an annular fluid container carrier portion
constructed and arranged to carry a plurality of containers as will
be described below.
[0183] Specimen ring 250 is preferably rotationally supported by
three 120.degree.-spaced V-groove rollers 257, 258, 260 which
engage a continuous V-ridge 262 formed on the inner periphery of
ring 250, as shown in FIGS. 5, 6, and 6A so that the ring 250 is
rotatable about a first central axis of rotation. The rollers are
preferably made by Bishop-Wisecarver Corp. of Pittsburgh, Calif.,
model number W1SSX. Rollers 257 and 260 are rotationally mounted on
fixed shafts, and roller 258 is mounted on a bracket which pivots
about a vertical axis and is spring biased so as to urge roller 258
radially outward against the inner periphery of ring 250. Having
two fixed rollers and one radially movable roller allows the three
rollers to accommodate an out-of-round inner periphery of the ring
250.
[0184] Specimen ring 250 is driven by stepper motor 264 (VEXTA
stepper motors available from Oriental Motor Co., Ltd. of Tokyo,
Japan as model number PK266-01A are preferred) via continuous belt
270 (preferably available from SDP/SI of New Hyde Park, N.Y., as
model number A6R3M444080) which extends over guide rollers 266, 268
and around the outer periphery of ring 250. A home sensor and a
sector sensor (not shown), preferably slotted optical sensors, are
provided adjacent the ring 250 at a rotational home position and at
a position corresponding to one of the specimen tube tray receiving
wells 256. The ring 250 includes a home flag (not shown) located at
a home position on the wheel and nine equally-spaced sector flags
(not shown) corresponding to the positions of each of the nine
specimen tube tray receiving wells 256. The home flag and sector
flags cooperate with the home sensor and sector sensors to provide
ring position information to the assay manager program and to
control the ring 250 to stop at nine discrete positions
corresponding to established coordinates for user re-load and
access by pipette unit 450. Preferred sensors for the home sensor
and sector sensor are Optek slotted optical sensors, model number
OPB 857, available from Optek of Carrollton, Tex.
[0185] A specimen cover is disposed over a portion of the annular
fluid container carrier portion, or trough 251, and comprises an
arcuate cover plate 138 fixed in an elevated position with respect
to the wheel 250 on three mounting posts 136. Plate 138 has an
arcuate shape generally conforming to the curve of the trough 251.
A first opening 142 is formed in the plate 138, and a second
opening 140 is formed in the plate 138 at a greater radial distance
from the axis of rotation of ring 250 than opening 142 and at a
circumferentially-spaced position from opening 142.
[0186] Referring to FIGS. 55-57, each specimen tube tray 300
comprises a test tube rack structure that is curved to conform to
the curvature of the ring 250. Each tray 300 comprises a central
wall structure 304 with lateral end walls 303 and 305 disposed on
either end of wall 304. A floor 312 extends across the bottom of
the tray 300. The principle purposes of specimen tube tray 300 are
to hold specimen tubes on the specimen ring 250 for access by the
specimen pipette assembly 450 and to facilitate loading and
unloading of multiple specimen tubes into and from the
analyzer.
[0187] A plurality of Y-shaped dividers 302 are equidistantly
spaced along opposite edges of the tray 300. Each two adjacent
dividers 302 define a test-tube receiving area 330. End wall 303
includes inwardly bent flanges 316 and 318, and end wall 305
includes inwardly bent flanges 326 and 328. The respective inwardly
bent flanges of end walls 303 and 305 along with the end-most of
the dividers 302 define the end-most tube receiving areas 332. The
receiving areas 330, 332 are arcuately aligned along two arcuate
rows on opposite sides of central wall structure 304
[0188] Referring to FIG. 57, within each tube receiving area 330,
332, a leaf spring element 310 is attached to central wall 304.
Leaf spring element 310, preferably formed of stainless spring
steel, elastically deflects when a test tube 320 is inserted into
the tube-receiving area 330 or 332 and urges the tube 320 outwardly
against the dividers 302. Thus, the tube 320 is secured in an
upright orientation. The shape of the dividers 302 and the
elasticity of the leaf spring elements 310 allow the tray 300 to
accommodate specimen tubes of various shapes and sizes, such as
tubes 320 and 324. Each tray 300 preferably includes nine dividers
302 along each edge to form, along with end walls 303 and 305, ten
tube-receiving areas 330, 332 on each side of central wall
structure 304 for a total of twenty tube-receiving areas per tray.
Indicia for designating tube-receiving areas 330 and 332, such as
raised numerals 306, may be provided on the tray, such as on
central wall 304.
[0189] Each tray 300 may also include boss structures 308, shown in
the illustrated embodiment to be integrally formed with the
end-most dividers 302. An upright inverted U-shaped handle (not
shown) may be attached to the tray at boss structures 308 or some
other suitable location. Upright handles can facilitate handling of
the tray 300 when loading and unloading the tray 300 through the
arcuate carousel door 80, but are not necessarily preferred.
[0190] A gap is provided between adjacent dividers 302 so that
bar-code labels 334, or other readable or scannable information, on
the tubes 320 is accessible when the tube is placed in the tray
300. When a tray 300 carried on wheel 250 passes beneath the plate
138 of the specimen cover, one tube 320 in a curved row at a
radially-inward position with respect to wall structure 304 will be
aligned with first opening 142 and another tube 320 in a curved row
at a radially-outward position with respect to wall 304 will be
aligned with second opening 140. The ring 250 is indexed to
sequentially move each tube 320 beneath the openings 140, 142 to
permit access to the tubes.
[0191] Referring again to FIG. 5, bar code scanners 272 and 274 are
disposed adjacent the ring 250. Opticon, Inc. scanners, model
number LHA2126RR1S-032, available from Opticon, Inc. of Orangeburg,
N.Y., are preferred. Scanner 272 is located outside ring 250, and
scanner 274 is disposed inside ring 250. Scanners 272 and 274 are
positioned to scan bar code data labels on each specimen tube 320
carried in the specimen tube tray 300 as the ring 250 rotates a
tray 300 of specimen tubes 320 past the scanners 272, 274. In
addition, the scanners 272, 274 scan the bar code label 337 (see
FIG. 55) on the outer portion of bent flanges 316 and 318 of end
wall 303 of each tray 300 as the tray 300 is brought into the
specimen preparation area. Various information, such as specimen
and assay identification, can be placed on the tubes and/or each
tray 300, and this information can be scanned by the scanners 272,
274 and stored in the central processing computer. If no specimen
tube is present, the tray 300 presents a special code 335 (see FIG.
55) to be read by the scanners 272, 274.
Pipette Tip Wheel
[0192] As shown primarily in FIGS. 5 and 6, a second ring assembly
of the preferred embodiment is a pipette tip wheel 350 and
comprises a circular ring 352 at a bottom portion thereof, a top
panel 374 defining a circular inner periphery and five
circumferentially-spaced, radially-protruding sections 370, and a
plurality of generally rectangular risers 354 separating the top
panel 374 from the ring 352 and preferably held in place by
mechanical fasteners 356 extending through the top panel 374 and
ring 352 into the risers 354. Five rectangular openings 358 are
formed in the top panel 374 proximate each of the sections 370, and
a rectangular box 376 is disposed beneath panel 374, one at each
opening 358. Top panel 374, ring 352, and risers 354 are preferably
made from machined aluminum, and boxes 376 are preferably formed
from stainless steel sheet stock.
[0193] The openings 358 and associated boxes 376 are constructed
and arranged to receive trays 372 holding a plurality of disposable
pipette tips. The pipette tip trays 372 are preferably those
manufactured and sold by TECAN (TECAN U.S. Inc., Research Triangle
Park, N.C.) under the trade name "Disposable Tips for GENESIS
Series". Each tip has a 1000 .mu.l capacity and is conductive. Each
tray holds ninety-six elongated disposable tips.
[0194] Lateral slots 378 and longitudinal slots 380 are formed in
the top panel 374 along the lateral and longitudinal edges,
respectively, of each opening 358. The slots 378, 380 receive
downwardly-extending flanges (not shown) disposed along the lateral
and longitudinal edges of the trays 372. The slots 378, 380 and
associated flanges of the trays 372 serve to properly register the
trays 372 with respect to openings 358 and to hold the trays 372 in
place on the panel 374.
[0195] Pipette tip wheel 350 is preferably rotationally supported
by three 120.degree.-spaced V-groove rollers 357, 360, 361 which
engage a continuous V-ridge 362 formed on the inner periphery of
ring 352, as shown in FIGS. 5, 6, and 6A, so that the pipette tip
wheel 350 is rotatable about a second central axis of rotation that
is generally parallel to the first axis of rotation of the specimen
ring 250. The rollers are preferably made by Bishop-Wisecarver
Corp. of Pittsburgh, Calif., model number W1SSX. Rollers 357 and
360 are rotationally mounted on fixed shafts, and roller 361 is
mounted on a bracket which pivots about a vertical axis and is
spring biased so as to urge roller 361 radially outwardly against
the inner periphery of ring 352. Having two fixed rollers and one
radially movable roller allows the three rollers to accommodate an
out-of-round inner periphery of ring 352. In addition, the wheel
350 can be easily installed and removed by merely pushing pivoting
roller 361 radially inwardly to allow the ring 352 to move
laterally to disengage continuous V-ridge 362 from the fixed
V-groove rollers 357, 360.
[0196] Pipette tip wheel 350 is driven by a motor 364 having a
shaft-mounted spur gear which meshes with mating gear teeth formed
on an outer perimeter of ring 352. Motor 364 is preferably a VEXTA
gear head stepper motor, model number PK243-A1-SG7.2, having a
7.2:1 gear reduction and available from Oriental Motor Co., Ltd. of
Tokyo, Japan. A gear head stepper motor with a 7.2:1 gear reduction
is preferred because it provides smooth motion of the pipette tip
wheel 350, where the spur gear of the motor 364 is directly engaged
with the ring 352.
[0197] A home sensor and a sector sensor (not shown), preferably
slotted optical sensors, are provided adjacent the pipette tip
wheel 350 at a rotational home position and at a position of one of
the boxes 376. The pipette tip wheel 350 includes a home flag (not
shown) located at a home position on the wheel and five
equally-spaced sector flags (not shown) corresponding to the
positions of each of the five boxes 376. The home flag and sector
flags cooperate with the home sensor and sector sensors to provide
wheel position information to the assay manager program and to
control the pipette tip wheel 350 to stop at five discrete
positions corresponding to established coordinates for user re-load
and access by pipette unit 450. Preferred sensors for the home
sensor and sector sensor are Optek Technology, Inc. slotted optical
sensors, model number OPB980, available from Optek Technology, Inc.
of Carrollton, Tex.
Multi-Axis Mixer
[0198] Referring to FIGS. 7-12, the multi-axis mixer 400 includes a
rotating turntable structure 414 (see FIG. 10) rotatably mounted on
a center shaft 428 supported in center bearings 430 to a fixed base
402 mounted to the jig plate 130 by means of mechanical fasteners
(not shown) extending through apertures 419 formed about the outer
periphery of the fixed base 402. A cover member 404 is attached to
and rotates with turntable 414.
[0199] Turntable 414 is preferably in the form of a right angle
cross comprising three 90.degree.-spaced rectangular arms 444 of
equal length extending radially outwardly from the center of the
turntable 414 and a fourth arm 445 having an extension 417 making
arm 445 slightly longer than arms 444. As shown in FIGS. 10-12, the
center portion of turntable 414 is connected to center shaft 428 by
a screw 429.
[0200] Four container holders 406 are disposed on the ends of the
arms 444 and 445 of turntable frame 414. Each container holder 406
is attached to one of four vertical shafts 423, which are rotatably
supported in container holder bearings 415. Container holder
bearings 415 are pressed into the arms 444, 445 of the turntable
414 and are disposed at equal radial distances from shaft 428.
[0201] The cover member 404 includes four circular openings with
upwardly-turned peripheral flanges 401 through which shafts 423
extend. Upward flanges 401 can advantageously prevent spilled
liquids from flowing into the openings.
[0202] The container holders 406 comprise generally cylindrical
members having an open bottom and an open top for receiving and
holding a container 440, preferably a plastic bottle, of target
capture reagent.
[0203] The target capture reagent used with the preferred assay
includes magnetically responsive particles with immobilized
polynucleotides, polynucleotide capture probes, and reagents
sufficient to lyse cells containing the targeted nucleic acids.
After cell lysis, targeted nucleic acids are available for
hybridization under a first set of predetermined hybridization
conditions with one or more capture probes, with each capture probe
having a nucleotide base sequence region which is capable of
hybridizing to a nucleotide base sequence region contained on at
least one of the targeted nucleic acids. Under a second set of
predetermined hybridization conditions, a homopolymer tail (e.g.,
oligo(dT)) of the immobilized polynucleotides is capable of
hybridizing with a complementary homopolymer tail (e.g., oligo(dA))
contained on the capture probe, thereby immobilizing targeted
nucleic acids. Target-capture methods and lysing procedures are
well known in the art and are described more fully in the
background section supra.
[0204] A container retainer spring 408 spans a lateral slot formed
in the wall of each container holder 406 and helps to hold the
container 440 within the container holder 406 by urging the
container 440 toward a portion of the inner peripheral wall of the
holder 406 opposite the spring 408.
[0205] Each container holder 406 is secured to an associated
vertical shaft 423 by a shaft block structure 432. Shaft block
structure 432 includes curved end portions which conform to the
inside of the cylindrical container holder 406, and the container
holder 406 is secured to the block 432 by fasteners 434. A
generally circular aperture 449 receives the shaft 423. A slot 438
extends from aperture 449 to an end of the block 432 which does not
extend all the way to the inside of the container holder 406, and a
second slot 436 extends from an edge of the block 432 generally
perpendicularly to slot 438 so as to define a cantilevered arm 435.
A machine screw 437 extends through a through-hole 441 formed
laterally through block 432 and into a threaded hole 447 formed
laterally through arm 435. As screw 437 is tightened, arm 435
deflects, thus tightening aperture 449 around shaft 423.
[0206] The shaft block structure 432, the shaft 423, and the
container holder bearings 415 associated with each container holder
406 define a preferred container holder mounting structure
associated with each container holder 406 that is constructed and
arranged to mount the container holder 406 to the turntable 414 and
permit the container holder 406 to rotate about an axis of rotation
412 of the shaft 423.
[0207] Container holder planetary gears 422 are attached to the
opposite ends of shafts 423. The planetary gears 422 operatively
engage a stationary sun gear 416. A drive pulley 418 is attached to
center shaft 428 and is coupled to a drive motor 420 by a drive
belt (not shown). Drive motor 420 is preferably mounted so as to
extend through an opening (not shown) in the jig plate 130 below
the base 402. Drive motor 420 is preferably a stepper motor, and
most preferably a VEXTA stepper motor, model number PK264-01A,
available from Oriental Motor Co., Ltd. of Tokyo, Japan. The drive
motor 420, via the drive belt and drive pulley 418, rotates the
center shaft 428 and the turntable 414 attached thereto. As the
turntable frame 414 rotates about the center line of center shaft
428, the planetary gears 422 engaged with sun gear 416 cause the
shafts 423 and container holders 406 attached thereto to rotate at
the ends of the arms 444 of the turntable frame 414. Each container
holder 406 is preferably mounted such that the axis of rotation 410
thereof is offset from the axis of rotation 412 of the associated
shaft 423. Thus, each container holder 406 rotates eccentrically
about axis 412 of the associated shaft 423. Accordingly, the
planetary gears 422 and the sun gear 416 constitute rotational
motion coupling elements constructed and arranged to cause the
container holders 406 to rotate about the respective axes of
rotation of the shafts 423 as the turntable 414 rotates about the
axis of rotation of the shaft 428.
[0208] A bar code scanner device 405 is preferably mounted on a
bracket 403 and reads bar code information of the containers 440
through a scanner slot 407 formed in each container holder 406. The
preferred scanner is a model number NFT1125/002RL scanner,
available from Opticon, Inc. of Orangeburg, N.Y.
[0209] The multi-axis mixer 400 usually rotates during operation of
the analyzer 50 to agitate the fluid contents of the containers 440
to thereby keep the target capture reagent in suspension, stopping
only briefly to permit pipette unit 456 to withdraw an amount of
mixture from one of the containers. Pipette unit 456 draws mixture
from a bottle at the same location each time. Therefore, it is
desirable to monitor the positions of the bottles so that the
bottle from which mixture is withdrawn each time can be
specified.
[0210] Four optical slotted sensors 426, each comprising an optical
emitter and detector, are stationed around the periphery of fixed
base 402, spaced at 90.degree. intervals. Optical sensors available
from Optek Technology, Inc. of Carrollton, Tex., model number
OPB490P11, are preferred. A sensor tab 424 extends down from
extension 417 at the end of arm 445 of the turntable 414. When
sensor tab 424 passes through a sensor 426, the communication
between the emitter and detector is broken thus giving a "container
present" signal. The tab 424 is only provided at one location,
e.g., the first container location. By knowing the position of the
first container, the positions of the remaining containers, which
are fixed relative to the first container, are also known.
[0211] Power and control signals are provided to the multi-axis
mixer 400 via a power and data connector. While the multi-axis
mixer 400 provides mixing by rotation and eccentric revolution,
other mixing techniques, such as vibration, inversion, etc. may be
used.
Specimen Preparation Procedure
[0212] To begin specimen preparation, the pipette unit 456 moves to
transfer target capture reagent, preferably mag-oligo reagent, from
a container 440 carried on the multi-axis mixer 400 into each of
the receptacle vessels 162 of the MTU 160. The target capture
reagent includes a support material able to bind to and immobilize
a target analyte. The support material preferably comprises
magnetically responsive particles. At the beginning of the specimen
preparation procedure, the pipette unit 456 of the right-side
pipette assembly 450 moves laterally and longitudinally to a
position in which the probe 457 is operatively positioned over a
pipette tip in one of the trays 372.
[0213] The tip trays 372 are carried on the pipette tip wheel 350
so as to be precisely positioned to achieve proper registration
between the pipette tips and the tubular probe 457 of the pipette
unit 456. The pipette unit 456 moves down to insert the free end of
the tubular probe 457 into the open end of a pipette tip and
frictionally engage the pipette tip. The Cavro processors
preferably used for pipette unit 456 includes a collar (not shown),
which is unique to Cavro processors. This collar is moved slightly
upwardly when a pipette tip is frictionally engaged onto the end of
the tubular probe 457, and the displaced collar trips an electrical
switch on the pipette unit 456 to verify that a pipette tip is
present. If tip pick-up is not successful (e.g., due to missing
tips in the trays 372 or a misalignment), a missing tip signal is
generated and the pipette unit 456 can move to re-try tip
engagement at a different tip location.
[0214] The assay manager program causes the multi-axis mixer 400 to
briefly stop rotating so that the pipette unit 456 can be moved to
a position with the tubular probe 457 and attached pipette tip of
the pipette unit 456 aligned over one of the stationary containers
440. The pipette unit 456 lowers the pipette tip attached to the
tubular probe 457 into the container 440 and draws a desired amount
of target capture reagent into the pipette tip. The pipette unit
456 then moves the probe 457 out of the container 440, the
multi-axis mixer 400 resumes rotating, and the pipette unit 456
moves to a position above opening 252 and the specimen transfer
station 255. Next, the pipette unit 456 descends, moving the
pipette tip and the tubular probe 457 through the opening 252, and
dispenses a required amount of target capture (typically 100-500
.mu.l) into one or more of the receptacle vessels 162 of the MTU
160. It is preferred that the target capture reagent is drawn only
into the pipette tip and not into the probe 457 itself.
Furthermore, it is preferred that the pipette tip be of sufficient
volumetric capacity to hold enough reagent for all five vessels 162
of the MTU 160.
[0215] After target capture reagent transfer, the pipette unit 456
then moves to a "tip discard" position above tip disposal tube 342,
where the disposable pipette tip is pushed or ejected off of the
end of the tubular probe 457 of the pipette unit 456, and falls
through tube 342 toward a solid waste container. An optical sensor
(not shown) is disposed adjacent to tube 342, and before tip
discard, the specimen pipette assembly 450 moves the pipette unit
456 into a sensing position of the sensor. The sensor detects
whether a tip is engaged with the end of the tubular probe 457 to
verify that the tip is still held on the tubular probe 457 of the
pipette unit 456, thereby confirming that the tip was on the
tubular probe 457 throughout specimen preparation. A preferred
sensor is a wide-gap slotted optic sensor, model OPB900W, available
from Optek Technology, Inc. of Carrollton, Tex.
[0216] Preferably, the pipette tip is ejected by the collar (not
shown) on the tubular probe 457 of pipette unit 456. The collar
engages a hard stop when the tubular probe 457 is raised, so that
as the probe 457 continues to ascend, the collar remains fixed and
engages an upper end of the pipette tip, thereby forcing it off the
tubular probe 457.
[0217] After pipetting the target capture and discarding the
pipette tip, the probe 457 of the pipette unit 456 can be washed by
running distilled water through the tubular probe 457 at the tip
wash station basin 346. The tip wash water is collected and drains
down into a liquid waste container.
[0218] Following the reagent dispensing procedure, the pipette unit
456 on the right pipette assembly 450 moves laterally and
longitudinally to a position in which the tubular probe 457 of the
pipette unit 456 is centered over a new pipette tip on one of the
tip trays 372. After successful tip engagement, the pipette unit
456 moves back over the specimen ring 250, adjacent to the specimen
preparation opening 252 and withdraws a test specimen (about 25-900
.mu.l) from a specimen tube 320 that is aligned with one of the
openings 140, 142 of the cover plate 138. Note that both openings
140, 142 include upwardly extending peripheral flanges to prevent
any fluids spilled onto the plate 138 from running into the
openings 140, 142. The pipette unit 456 then moves over the MTU 160
in the specimen transfer station 255, moves down through opening
252, and dispenses test specimen into one of the receptacle vessels
162 of the MTU 160 containing target capture reagent. Pipette unit
456 then moves to the "tip discard" position above the tip disposal
tube 342, and the disposable pipette tip is ejected into the tube
342. Pipette unit 456 then picks up a new disposable pipette tip
from the pipette tip wheel 350, the specimen ring 250 indexes so
that a new specimen tube is accessible by the pipette unit 456,
unit 456 moves to and draws specimen fluid from the specimen tube
into the disposable pipette tip, the pipette unit 456 then moves to
a position above the specimen transfer station 255, and dispenses
specimen fluid into a different receptacle vessel 162 containing
target capture reagent. This process is preferably repeated until
all five receptacle vessels 162 contain a combination of fluid
specimen sample and target capture reagent.
[0219] Alternatively, depending on the assay protocol or protocols
to be run by the analyzer 50, the pipette unit 456 may dispense the
same test specimen material into two or more of the receptacle
vessels 162 and the analyzer can perform the same or different
assays on each of those aliquots.
[0220] As described above with respect to pipette units 480, 482,
pipette unit 456 also includes capacitive level sensing capability.
The pipette tips used on the end of the tubular probe 457 are
preferably made from a conductive material, so that capacitive
level sensing can be performed with the pipette unit 456, even when
a tip is carried on the end of the tubular probe 457. After the
pipette unit has completed a test specimen dispensing procedure,
the pipette unit 456 moves the tubular probe 457 back down into the
receptacle vessel 162 until the top of the fluid level is detected
by the change in capacitance. The vertical position of the tubular
probe 457 is noted to determine whether the proper amount of fluid
material is contained in the receptacle vessel 162. Lack of
sufficient material in a receptacle vessel 162 can be caused by
clotting in the test specimen, which can clot the tip at the end of
the tubular probe 457 and prevent proper aspiration of test
specimen material into the tip and/or can prevent proper dispensing
of test specimen from the tip.
[0221] After specimen transfer, the pipette tip is discarded into
the tip disposal tube 342 as described above. Again, the tubular
probe 457 of the pipette of unit can be washed with distilled water
if desired, but washing of the probe is typically not necessary
because, in the preferred method of operation, specimen material
only comes into contact with the disposable pipette tip.
[0222] The assay manager program includes pipette unit control
logic which controls movements of the pipette units 456, 480, 482,
and preferably causes pipette unit 456 to move in such a manner
that it never passes over a specimen tube 320 on the specimen ring
250, except when the pipette unit 456 positions the tubular probe
457 over a specimen tube 320 to withdraw a test specimen or when
the specimen tube 320 is below the plate 138 of the specimen cover.
In this way, inadvertent fluid drips from the tubular probe 457 of
the pipette unit 450 into another specimen tube, which might result
in cross-contamination, are avoided.
[0223] Following specimen preparation, the MTU 160 is moved by the
right-side transport mechanism 500 from the specimen transfer
station to the right orbital mixer 550 in which the
specimen/reagent mixtures are mixed. The structure and operation of
the orbital mixers 550, 552 will be described in further detail
below.
[0224] After the MTU 160 is withdrawn from the specimen transfer
station by the right-side transport mechanism 500, the reaction
receptacle shuttle assembly within the input queue 150 advances the
next MTU into a position to be retrieved by the right-side
transport mechanism 500 which moves the next MTU to the specimen
transfer station. Specimen preparation procedures are then repeated
for this next MTU.
Transport Mechanisms
[0225] The right-side and left-side transport mechanisms 500, 502
will now be described in detail. Referring to FIGS. 13-16, the
right-side transport mechanism 500 (as well as the left-side
transport mechanism 502) has a manipulating hook member that, in
the illustrated embodiment, includes an extendible distributor hook
506 extending from a hook mounting structure 508 that is radially
and slidably displaceable in a slot 510 on a plate 512. A housing
504 on top of the plate 512 has an opening 505 configured to
receive the upper portion of an MTU 160. A stepper motor 514
mounted on the plate 512 turns a threaded shaft 516, which, in
cooperation with a lead screw mechanism, moves the distributor hook
506 from the extended position shown in FIGS. 13 and 15, to the
retracted position shown in FIG. 14, the motor 514 and threaded
shaft 516 constituting elements of a preferred hook member drive
assembly. Stepper motor 514 is preferably a modified HSI, series
46000. HSI stepper motors are available from Haydon Switch and
Instrument, Inc. of Waterbury, Conn. The HSI motor is modified by
machining the threads off one end of the threaded shaft 516, so
that the shaft 516 can receive the hook mounting structure 508.
[0226] The housing 504, motor 514, and the plate 512 are preferably
covered by a conforming shroud 507.
[0227] As shown in FIG. 16, a stepper motor 518 turns a pulley 520
via a belt 519. (VEXTA stepper motors, model number PK264-01A,
available from Oriental Motor Co., Ltd. of Tokyo, Japan, and SDP
timing belts, model number A6R51M200060, available from SDP/SI of
New Hyde Park, N.Y., are preferred). Pulley 520 is preferably a
custom-made pulley with one hundred sixty-two (162) axial grooves
disposed around its perimeter. A main shaft 522 fixedly attached to
the plate 512, by means of a uniquely-shaped mounting block 523,
extends down through a base 524 and is fixed to the pulley 520.
Base 524 is mounted to the datum plate 82 by means of mechanical
fasteners extending through apertures 525 formed about the outer
periphery of the base 524. A flex circuit 526 provides power and
control signals to the hook mounting structure 508 and motor 514,
while allowing the plate 512 (and the components carried on the
plate) to pivot sufficiently so as to rotate as much as 340.degree.
with respect to the base 524. The transport mechanism 500, 502,
assembly preferably includes hard stops (not shown) at either end
of the unit's rotational path of travel.
[0228] An arm position encoder 531 is preferably mounted on an end
of the main shaft 522. The arm position encoder is preferably an
absolute encoder. A2 series encoders from U.S. Digital in Seattle,
Wash., model number A2-S-K-315-H, are preferred.
[0229] The assay manager program provides control signals to the
motors 518 and 514, and to the hook mounting structure 508, to
command the distributor hook 506 to engage the MTU manipulating
structure 166 on MTU 160. With the hook 506 engaged, the motor 514
can be energized to rotate the shaft 516 and thereby withdraw the
hook 506, and the MTU 160, back into the housing 504. The MTU 160
is securely held by the transport mechanism 500, 502 via the
sliding engagement of the connecting rib structure 164 of the MTU
160 with opposed edges 511 of plate 512 adjacent slot 510. The
plate 512 thereby constitutes an element of a preferred receptacle
carrier assembly that is constructed and arranged to be rotatable
about an axis of rotation (e.g., the axis of shaft 522) and to
receive and carry a reaction receptacle (e.g., MTU 160). The motor
518 can rotate the pulley 520 and shaft 522 via the belt 519 to
thereby rotate the plate 512 and housing 504 with respect to the
base 524. Rotation of the housing 504 thus changes the orientation
of the engaged MTU, thereby bringing that MTU into alignment with a
different station on the processing deck.
[0230] Sensors 528, 532 are provided in opposite sides of the
housing 504 to indicate the position of the distributor hook 506
within the housing 504. Sensor 528 is an end-of-travel sensor, and
sensor 532 is a home sensor. Sensors 528, 532 are preferably
optical slotted sensors available from Optek Technology, Inc. of
Carrollton, Tex., model number OPB980T11. For the home sensor 532,
the sensor beam is broken by a home flag 536 extending from the
hook mounting structure 508 when the hook 506 is in its fully
retracted position. The beam of the end-of-travel sensor 528 is
broken by an end-of-travel flag 534 extending from the opposite
side of the hook mounting structure 508 when the hook 506 is fully
extended.
[0231] An MTU-present sensor 530 mounted in the side of the housing
504 senses the presence of an MTU 160 in the housing 504. Sensor
530 is preferably a SUNX, infra-red sensor, available from
SUNX/Ramco Electric, Inc., of West Des Moines, Iowa.
Temperature Ramping Stations
[0232] One or more temperature ramping stations 700 are preferably
disposed below the jig plate 130 and specimen ring 250 (no
temperature ramping stations located below the specimen ring 250
are shown in the figures). After mixing the contents of the MTU 160
within the orbital mixer 550, the right-side transport mechanism
500 may move the MTU 160 from the right orbital mixer 550 to a
temperature ramping station 700, depending on the assay
protocol.
[0233] The purpose of each ramping station 700 is to adjust the
temperature of an MTU 160 and its contents up or down as desired.
The temperature of the MTU and its contents may be adjusted to
approximate an incubator temperature before inserting the MTU into
the incubator to avoid large temperature fluctuations within the
incubator.
[0234] As shown in FIGS. 17-18, a temperature ramping station 700
includes a housing 702 in which an MTU 160 can be inserted. The
housing 702 includes mounting flanges 712, 714 for mounting the
ramping station 700 to the datum plate 82. A thermoelectric module
704 (also known as a Peltier device) in thermal contact with a heat
sink structure 706 is attached to the housing 702, preferably at
the bottom 710. Preferred thermoelectric modules are those
available from Melcor, Inc. of Trenton, N.J. model number
CP1.4-127-06L. Although one thermoelectric module 704 is shown in
FIG. 17, the ramping station 700 preferably includes two such
thermoelectric modules. Alternatively, the outer surface of the
housing 702 could be covered with a mylar film resistive heating
foil material (not shown) for heating the ramping station. Suitable
mylar film heating foils are etched foils available from Minco
Products, Inc. of Minneapolis, Minn. and from Heatron, Inc. of
Leavenworth, Kans. For ramp-up stations (i.e., heaters), resistive
heating elements are preferably used, and for ramp-down stations
(i.e., chillers), thermoelectric modules 704 are preferably used.
The housing 702 is preferably covered with a thermal insulating
jacket structure (not shown).
[0235] The heat sink structure used in conjunction with the
thermoelectric module 704 preferably comprises an aluminum block
with heat dissipating fins 708 extending therefrom.
[0236] Two thermal sensors (not shown) (preferably thermistors
rated 10 KOhm at 25.degree. C.) are preferably provided at a
location on or within the housing 702 to monitor the temperature.
YSI 44036 series thermistors available from YSI, Inc. of Yellow
Springs, Ohio are preferred. YSI thermistors are preferred because
of their high accuracy and the .+-.0.1.degree. C.
interchangeability provided by YSI thermistors from one thermistor
to another. One of the thermal sensors is for primary temperature
control, that is, it sends signals to the embedded controller for
controlling temperature within the ramping station, and the other
thermal sensor is for monitoring ramping station temperature as a
back-up check of the primary temperature control thermal sensor.
The embedded controller monitors the thermal sensors and controls
the heating foils or the thermoelectric module of the ramping
station to maintain a generally uniform, desired temperature within
the ramping station 700.
[0237] An MTU 160 can be inserted into the housing, supported on
the MTU support flanges 718 which engage the connecting rib
structure 164 of the MTU 160. A cut-out 720 is formed in a front
edge of a side panel of the housing 702. The cut-out 720 permits a
distributor hook 506 of a transport mechanism 500 or 502 to engage
or disengage the MTU manipulating structure 166 of an MTU 160
inserted all the way into a temperature ramping station 700 by
lateral movement with respect thereto.
Rotary Incubators
[0238] Continuing with the general description of the assay
procedure, following sufficient temperature ramp-up in a ramping
station 700, the right-side transport mechanism 500 retrieves the
MTU from the ramping station 700 and places the MTU 160 into the
target capture and annealing incubator 600. In a preferred mode of
operation of the analyzer 50, the target capture and annealing
incubator 600 incubates the contents of the MTU 160 at about
60.degree. C. For certain tests, it is important that the annealing
incubation temperature not vary more than .+-.0.5.degree. C. and
that amplification incubation (described below) temperature not
vary more than .+-.0.1.degree. C. Consequently, the incubators are
designed to provide a consistent uniform temperature.
[0239] The details of the structure and operation of the two
embodiments of the rotary incubators 600, 602, 604 and 606 will now
be described. Referring to FIGS. 19-23C, each of the incubators has
housing with a generally cylindrical portion 610, suitably mounted
to the datum plate 82, within an insulating jacket 612 and an
insulated cover 611.
[0240] The cylindrical portion 610 is preferably constructed of
nickel-plated cast aluminum and the metal portion of the cover 611
is preferably machined aluminum. The cylindrical portion 610 is
preferably mounted to the datum plate 82 atop three or more resin
"feet" 609. The feet 609 are preferably formed of Ultem.RTM.-1000
supplied by General Electric Plastics. The material is a poor
thermal conductor, and therefore the feet 609 function to thermally
isolate the incubator from the datum plate. The insulation 612 and
the insulation for the cover 611 are preferably comprised of 1/2
inch thick polyethylene supplied by the Boyd Corporation of
Pleasantown, Calif.
[0241] Receptacle access openings 614, 616 are formed in the
cylindrical portion 610, and cooperating receptacle access openings
618, 620 are formed in the jacket 612. For incubators 600 and 602,
one of the access openings is positioned to be accessible by the
right-side transport mechanism 500 and the other access opening is
positioned to be accessible by the left-side transport mechanism
502. Incubators 604 and 606 need to be accessible only by the
left-side transport mechanism 502 and therefore only have a single
receptacle access opening.
[0242] Closure mechanisms comprising revolving doors 622, 624 are
rotatably positioned within the openings 614 and 616. Each
revolving door 622, 624 has a MTU slot 626 extending through a
solid cylindrical body. The MTU slot 626 is configured to closely
match the profile of the MTU 160, having a wider upper portion
compared to the lower portion. A door roller 628, 630 is attached
on top of each of the doors 622, 624, respectively. The revolving
doors 622, 624 are actuated by solenoids (not shown) which are
controlled by commands from the assay manager program to open and
close the doors 622, 624 at the proper times. A door 622 or 624 is
opened by turning the door 622, 624 so that the MTU slot 626
thereof is aligned with the respective receptacle access opening
614, 616 and is closed by turning the door 622, 624 so that the MTU
slot 626 thereof extends transversely to the respective access
opening 614, 616. The cylindrical portion 610, cover 611, doors
622, 624, and a floor panel (not shown) constitute an enclosure
which defines the incubation chamber.
[0243] The doors 622, 624 are opened to permit insertion or
retrieval of an MTU into or from an incubator and are closed at all
other times to minimize heat loss from the incubator through the
access openings 614, 616.
[0244] A centrally positioned radial fan 632 is driven by an
internal fan motor (not shown). A Papst, model number RER 100-25/14
centrifugal fan, available from ebm/Papst of Farmington, Conn.,
having a 24 VDC motor and rated at 32 cfm is preferred because its
shape is well-suited to application within the incubator.
[0245] Referring now to FIG. 22, an MTU carousel assembly 671 is a
preferred receptacle carrier which carries a plurality of radially
oriented, circumferentially-arranged MTUs 160 within the incubator.
The MTU carousel assembly 671 is carried by a top plate 642, which
is supported by the cylindrical portion 610 of the housing, and is
preferably actuated by a rotation motor 640, preferably a stepper
motor, supported at a peripheral edge of on the top plate 642.
Rotation motor 640 is preferably a VEXTA stepper motor, model
number PK246-01A, available from Oriental Motor Co., Ltd. of Tokyo,
Japan.
[0246] The MTU carousel 671 includes a hub 646 disposed below the
top plate 642 and coupled, via a shaft 649 extending through the
top plate 642, to a pulley 644. Pulley 644 is preferably a
custom-made pulley with one hundred sixty-two (162) axial grooves
disposed around its perimeter and is coupled to motor 640 through a
belt 643, so that motor 640 can rotate the hub 646. Belt 643 is
preferably a GT.RTM. series timing belt available from SDP/SI of
New Hyde Park, N.Y. A 9:1 ratio is preferably provided between the
pulley 644 and the motor 640. The hub 646 has a plurality of
equally spaced-apart internal air flow slots 645 optionally
separated by radially-oriented, circumferentially arranged divider
walls 647. In the illustration, only three divider walls 647 are
shown, although it will be understood that divider walls may be
provided about the entire circumference of the hub 646. In the
preferred embodiment, divider walls 647 are omitted. A support disk
670 is attached to hub 646 and disposed below top plate 642 in
generally parallel relation therewith. A plurality of radially
extending, circumferentially-arranged MTU holding members 672 are
attached to the bottom of the support disk 670 (only three MTU
holding members 672 are shown for clarity). The MTU holding members
672 have support ridges 674 extending along opposite sides thereof.
Radially oriented MTUs are carried on the MTU carousel assembly 671
within stations 676 defined by circumferentially adjacent MTU
holding members 672, with the support ridges 674 supporting the
connecting rib structures 164 of each MTU 160 carried by the MTU
carousel assembly 671.
[0247] The MTU carousel assembly rotates on a carousel drive shaft
to which the drive pulley (644 in the illustrated embodiment) is
attached. A carousel position encoder is preferably mounted on an
exterior end of the carousel drive shaft. The carousel position
encoder preferably comprises a slotted wheel and an optical slot
switch combination (not shown). The slotted wheel can be coupled to
the carousel assembly 671 to rotate therewith, and the optical slot
switch can be fixed to the cylindrical portion 610 of the housing
or top plate 642 so as to be stationary. The slotted wheel/slot
switch combination can be employed to indicate a rotational
position of the carousel assembly 671 and can indicate a "home"
position (e.g., a position in which an MTU station 676 designated
the #1 station is in front of the access opening 614). A2 series
encoders from U.S. Digital in Seattle, Wash., model number
A2-S-K-315-H, are preferred.
[0248] A heat source is provided in thermal communication with the
incubator chamber defined within the incubator housing comprising
the cylindrical portion 610 and cover 611. In the preferred
embodiment, Mylar film-encased electrically-resistive heating foils
660 surround the housing 610 and may be attached to the cover 611
as well. Preferred mylar film heating foils are etched foils
available from Minco Products, Inc. of Minneapolis, Minn. and
Heatron, Inc. of Leavenworth, Kans. Alternative heat sources may
include internally mounted resistive heating elements,
thermal-electric heating chips (Peltiers), or a remote
heat-generating mechanism thermally connected to the housing by a
conduit or the like.
[0249] As shown in FIGS. 19 and 22, a pipette slot 662 extends
through the incubator cover 611, radially-aligned pipette holes 663
extend through the top plate 642, and pipettes slots 664 are formed
in the support disk 670 over each MTU station 676, to allow
pipetting of reagents into MTUs disposed within the incubators. In
the preferred embodiment of the analyzer 50 for the preferred mode
of operation, only two of the incubators, the amplification
incubator 604 and the hybridization protection assay incubator 606,
include the pipette holes 663 and pipette slots 662 and 664,
because, in the preferred mode of operation, it is only in these
two incubators where fluids are dispensed into MTUs 160 while they
are in the incubator.
[0250] Two temperature sensors 666, preferably thermistors (10 KOhm
at 25.degree. C.), are positioned in the top plate 642. YSI 44036
series thermistors available from YSI, Inc. of Yellow Springs, Ohio
are preferred. YSI thermistors are preferred because of their high
accuracy and the .+-.0.1.degree. C. interchangeability provided by
YSI thermistors from one thermistor to another. One of the sensors
666 is for primary temperature control, that is, it sends singles
to the embedded controller for controlling temperature within the
incubator, and the other sensor is for monitoring temperature of
the incubator as a back-up check of the primary temperature control
sensor. The embedded controller monitors the sensors 666 and
controls the heating foils 660 and fan 632 to maintain a uniform,
desired temperature within the incubator housing 610.
[0251] As a transport mechanism 500, 502 prepares to load an MTU
160 into an incubator 600, 602, 604, or 606, the motor 640 turns
the hub 646 to bring an empty MTU station 676 into alignment with
the receptacle access opening 614 (or 616). As this occurs, the
door-actuating solenoid correspondingly turns the revolving door
622 (or 624) one-quarter turn to align the MTU slot 626 of the door
with the MTU station 676. The access opening 614 is thus exposed to
allow placement or removal of an MTU 160. The transport mechanism
500 or 502 then advances the distributor hook 506 from the
retracted position to the extended position, pushing the MTU 160
out of the housing 504, through the access opening 614, and into an
MTU station 676 in the incubator. After the distributor hook 506 is
withdrawn, the motor 640 turns the hub 646, shifting the previously
inserted MTU 160 away from the access opening 614, and the
revolving door 622 closes once again. This sequence is repeated for
subsequent MTUs inserted into the rotary incubator. Incubation of
each loaded MTU continues as that MTU advances around the incubator
(counter-clockwise) towards the exit slot 618.
[0252] An MTU sensor (preferably an infrared optical reflective
sensor) in each of the MTU stations 676 detects the presence of an
MTU 160 within the station. Optek Technology, Inc. sensors, model
number OPB770T, available from Optek Technology, Inc. of
Carrollton, Tex. are preferred because of the ability of these
sensors to withstand the high temperature environment of the
incubators and because of the ability of these sensors to read bar
code data fixed to the label-receiving surfaces 175 of the
label-receiving structures 174 of the MTUs 160. In addition, each
door assembly (revolving doors 622, 624) preferably includes
slotted optical sensors (not shown) to indicate door open and door
closed positions. Sensors available from Optek Technology, Inc. of
Carrollton, Tex., model number OPB980T11, are preferred because of
the relatively fine resolution provided thereby to permit accurate
monitoring of door position. A skewed disk linear mixer (also known
as a wobbler plate) 634 is provided within housing 610 adjacent MTU
carousel assembly 671 and operates as a receptacle mixing
mechanism. The mixer 634 comprises a disk mounted in a skewed
manner to the shaft of a motor 636 which extends through opening
635 into the housing 610. The motor is preferably a VEXTA stepper
motor, model number PK264-01A, available from Oriental Motors Ltd.
of Tokyo, Japan, which is the same motor preferably used for the
MTU carousel assembly 671. A viscous harmonic damper 638 is
preferably attached to motor 636 to damp out harmonic frequencies
of the motor which can cause the motor to stall. Preferred harmonic
dampers are VEXTA harmonic dampers, available from Oriental Motors
Ltd. The operation of the skewed disk linear mixer 634 will be
described below.
[0253] Only two of the incubators, the amplification incubator 604
and the hybridization protection assay incubator 606, include a
skewed disk linear mixer 634, because, in the preferred mode of
operation, it is only in these two incubators where fluids are
dispensed into the MTUs 160 while they are in the incubator. Thus,
it is only necessary to provide linear mixing of the MTU 160 by the
skewed disk linear mixer 634 in the amplification incubator 604 and
the hybridization protection assay incubator 606.
[0254] To effect linear mixing of an MTU 160 in the incubator by
linear mixer 634, the MTU carousel assembly 671 moves the MTU 160
into alignment with the skewed disk linear mixer 634, and the
skewed disk of the skewed disk linear mixer 634 engages the MTU
manipulating structure 166 of the MTU 160. As the motor 636 spins
the skewed disk of the skewed disk linear mixer 634, the portion of
the skewed disk structure engaged with the MTU 160 moves radially
in and out with respect to the wall of the housing 610, thus
alternately engaging the vertical piece 167 of the MTU manipulating
structure 166 and the shield structure 169. Accordingly, the MTU
160 engaged with the skewed disk linear mixer 634 is moved radially
in and out, preferably at high frequency, providing linear mixing
of the contents of the MTU 160. For the amplification incubation
step of the preferred mode of operation, which occurs within the
amplification incubator 604, a mixing frequency of 10 Hz is
preferred. For the probe incubation step of the preferred mode of
operation, which occurs within the hybridization protection assay
incubator 606, a mixing frequency of 14 Hz is preferred. Finally,
for the select incubation step of the preferred mode of operation,
which also occurs within the hybridization protection assay
incubator 606, a mixing frequency of 13 Hz is preferred.
[0255] The raised arcuate portions 171, 172 may be provided in the
middle of the convex surfaces of the vertical piece 167 and the
shield structure 169 of the MTU 160, respectively, (see FIG. 60) to
minimize the surface contact between the skewed disk linear mixer
634 and the MTU 160 so as to minimize friction between the MTU 160
and the skewed disk linear mixer 634.
[0256] In the preferred embodiment, a sensor is provided at the
skewed disk linear mixer 634 to ensure that the skewed disk linear
mixer 634 stops rotating in the "home" position shown in FIG. 21,
so that MTU manipulating structure 166 can engage and disengage
from the skewed disk linear mixer 634 as the MTU carousel assembly
671 rotates. The preferred "home" sensor is a pin extending
laterally from the skewed disk linear mixer structure and a slotted
optical switch which verifies orientation of the skewed disk linear
mixer assembly when the pin interrupts the optical switch beam.
Hall effect sensors based on magnetism may also be used.
[0257] An alternate MTU carousel assembly and carousel drive
mechanism are shown in FIGS. 23A and 23C. As shown in FIG. 23A, the
alternate incubator includes a housing assembly 1650 generally
comprising a cylindrical portion 1610 constructed of nickel-plated
cast aluminum, a cover 1676 preferably formed of machined aluminum,
insulation 1678 for the cover 1676, and an insulation jacket 1651
surrounding the cylindrical portion 1610. As with the previously
described incubator embodiment, the incubator may include a linear
mixer mechanism including a linear mixer motor 636 with a harmonic
damper 638. A closure mechanism 1600 (described below) operates to
close off or permit access through a receptacle access opening
1614. As with the previously described embodiment, the incubator
may include one or two access openings 1614 depending on the
location of the incubator and its function within the analyzer
50.
[0258] A centrifugal fan 632 is mounted at a bottom portion of the
housing 1650 and is driven by a motor (not shown). A fan cover 1652
is disposed over the fan and includes sufficient openings to permit
air flow generated by the fan 632. A carousel support shaft 1654
includes a lower shaft 1692 and an upper shaft 1690 divided by a
support disk 1694. The support shaft 1654 is supported by means of
the lower shaft 1692 extending down into the fan cover 1652 where
it is rotatably supported and secured by bearings (not shown).
[0259] An MTU carousel 1656 includes an upper disk 1658 having a
central portion 1696. A top surface of the support disk 1694
engages and is attached to a bottom surface of the central portion
1696 of the upper disk 1658 so that the weight of the carousel 1656
is supported from below. As shown in FIG. 23C, a plurality of
radially extending, circumferentially spaced station dividers 1660
are attached beneath the upper disk 1658. A lower disk 1662
includes a plurality of radial flanges 1682 emanating from an
annular inner portion 1688. The radial flanges 1682 correspond in
number and spacing to the carousel station dividers 1660, and the
lower disk 1662 is secured to the bottom surfaces of the carousel
station dividers 1660, with each flange 1682 being secured to an
associated one of the dividers 1660.
[0260] The radial flanges 1682 define a plurality of radial slots
1680 between adjacent pairs of flanges 1682. As can be appreciated
from FIG. 23C, the width in the circumferential direction of each
flange 1682 at an inner end 1686 thereof is less than the width in
the circumferential direction of the flange 1682 at the outer end
1684 thereof. The tapered shape of the flanges 1682 ensures that
the opposite sides of the slots 1680 are generally parallel to one
another.
[0261] When the lower disk 1662 is attached beneath the carousel
station dividers 1660, the widths of the flanges along at least a
portion of their respective lengths are greater than the widths of
the respective dividers 1660, which may also be tapered from an
outer end thereof toward an inner end thereof. The flanges 1684
define lateral shelves along the sides of adjacent pairs of
dividers 1660 for supporting the connecting rib structure 164 of an
MTU 160 inserted into each MTU station 1663 defined between
adjacent pairs of dividers 1660.
[0262] A pulley 1664 is secured to the top of the central portion
1696 of the upper disk 1658 and a motor 1672 is carried by a
mounting bracket 1670 which spans the diameter of the housing 1650
and is secured to the cylindrical portion 1610 of the housing at
opposite ends thereof. The motor is preferably a Vexta PK264-01A
stepper motor, and it is coupled to the pulley (having a 9:1 ratio
with respect to the motor) by a belt 1666, preferably one supplied
by the Gates Rubber Company. A position encoder 1674 is secured to
a top central portion of the mounting bracket 1672 and is coupled
with the upper shaft 1690 of the carousel support shaft 1654. The
encoder 1674 (preferably an absolute encoder of the A2 series by
U.S. Digital Corporation of Vancouver, Wash.) indicates the
rotational position of the carousel 1656.
[0263] An incubator cover is defined by an incubator plate 1676,
preferably formed of machined aluminum, and a conforming cover
insulation element 1678. Cover plate 1676 and insulation element
1678 include appropriate openings to accommodate the encoder 1674
and the motor 1672 and may also include radial slots formed therein
for dispensing fluids into MTUs carried within the incubator as
described with regard to the above embodiment.
[0264] An alternate, and preferred, closure mechanism 1600 is shown
in FIG. 23B. The cylindrical portion 1610 of the incubator housing
includes at least one receptacle access opening 1614 with outwardly
projecting wall portions 1616, 1618 extending integrally from the
cylindrical portion 1610 along opposite sides of the access opening
1614.
[0265] A rotating door 1620 is operatively mounted with respect to
the access opening 1614 by means of a door mounting bracket 1636
attached to the cylindrical portion 1610 of the housing above the
access opening 1614. Door 1620 includes an arcuate closure panel
1622 and a transversely extending hinge plate portion 1628 having a
hole 1634 for receiving a mounting post (not shown) of the door
mounting bracket 1636. The door 1622 is rotatable about the opening
1634 with respect to the access opening 1614 between a first
position in which the arcuate closure panel 1622 cooperates with
the projecting wall portions 1616, 1618 to close off the access
opening 1614 and a second position rotated outwardly with respect
to the access opening 1614 to permit movement of a receptacle
through the access opening 1614. An inner arcuate surface of the
arcuate panel 1622 conforms with an arcuate surface 1638 of the
door mounting bracket 1636 and an arcuate surface 1619 disposed
below the receptacle access opening 1614 to permit movement of the
arcuate panel 1622 with respect to the surfaces 1638 and 1619 while
providing a minimum gap between the respective surfaces so as to
minimize heat loss therethrough.
[0266] The door 1620 is actuated by a motor 1642 mounted to the
incubator housing by means of a motor mounting bracket 1640 secured
to the cylindrical portion 1610 of the housing beneath the
receptacle access opening 1614. A motor shaft 1644 is coupled to a
lower actuating plate 1626 of the rotating door 1620 so that
rotation of the shaft 1644 is transmitted into rotation of the
rotating door 1620. Motor 1642 is most preferably an HSI
7.5.degree. per step motor available from Haydon Switch and
Instrument, Inc. of Waterbury, Conn. The HSI motor is chosen
because of its relatively low cost and because the closure assembly
1600 does not require a high torque, robust motor.
[0267] Door position sensors 1646 and 1648 (preferably slotted
optical sensors) are operatively mounted on opposite sides of the
door mounting bracket 1636. The sensor 1646 and 1648 cooperate with
sensor tabs 1632 and 1630 on the hinge plate 1628 of the door 1620
for indicating the relative position of the rotating door 1620 and
can be configured so as to indicate, for example, a door open and a
door closed status.
[0268] A door cover element 1612 is secured to the outside of the
cylindrical portion 1610 of the housing so as to cover the door
mounting bracket 1636 and a portion of the rotating door 1620. The
cover element 1612 includes an access opening 1613 aligned with the
access opening 1614 of the incubator housing and further includes a
receptacle bridge 1615 extending laterally from a bottom edge of
the access opening 1613. The receptacle bridge 1615 facilitates the
insertion of a receptacle (e.g., an MTU 160) into and withdrawal of
the receptacle from the incubator.
[0269] While in the target capture and annealing incubator 600, the
MTU 160 and test specimens are preferably kept at a temperature of
about 60.degree. C. .+-.0.5.degree. C. for a period of time
sufficient to permit hybridization between capture probes and
target nucleic acids. Under these conditions, the capture probes
will preferably not hybridize with those polynucleotides directly
immobilized by the magnetic particles.
[0270] Following target capture incubation in the target capture
and annealing incubator 600, the MTU 160 is rotated by the
incubator carousel to the entrance door 622, also known as the
right-side or number one distributor door. The MTU 160 is retrieved
from its MTU station 676 within incubator 600 and is then
transferred by the right-side transport mechanism 500 to a
temperature ramp-down station (not shown) below the specimen ring
250. In the ramp-down station, the MTU temperature is brought down
to the level of the next incubator. This ramp-down station that
precedes the active temperature and pre-read cool-down incubator
602 is technically a heater, as opposed to a chiller, because the
temperature to which the MTU is decreased, about 40.degree. C., is
still greater than the ambient analyzer temperature, about
30.degree. C. Accordingly, this ramp-down station preferably uses
resistive heating elements, as opposed to a thermoelectric
module.
[0271] From the ramp-down station, the MTU 160 is transferred by
the right-side transfer mechanism 500 into the active temperature
and pre-read cool-down incubator 602. The design and operation of
the active temperature and pre-read cool-down 602 is similar to
that of the target capture and annealing incubator 600, as
described above, except that the active temperature and pre-read
cool-down incubator 602 incubates at 40.+-.1.0.degree. C.
[0272] In the AT incubator 602, the hybridization conditions are
such that the polythymidine tail of the immobilized polynucleotide
can hybridize to the polyadenine tail of the capture probe.
Provided target nucleic acid has hybridized with the capture probe
in the annealing incubator 600, a hybridization complex can be
formed between the immobilized polynucleotide, the capture probe
and the target nucleic acid in the AT incubator 602, thus
immobilizing the target nucleic acid. In the AT incubator 602, the
hybridization conditions are such that the polythymidine tail of
the immobilized polynucleotide can hybridize to the polyadenine
tail of the capture probe. Provided target nucleic acid has
hybridized with the capture probe in the annealing incubator 600, a
hybridization complex can be formed between the immobilized
polynucleotide, the capture probe and the target nucleic acid in
the AT incubator 602, thus immobilizing the target nucleic
acid.
[0273] During active temperature binding incubation, the carousel
assembly 1656 (or 671) of the active temperature and pre-read
cool-down incubator 602 rotates the MTU to the exit door 624, also
known as the number two, or left-side, distributor door, from which
the MTU 160 can be removed by the left-side transport mechanism
502. The left-side transport mechanism 502 removes the MTU 160 from
the active temperature and pre-read cool-down incubator 602 and
places it into an available magnetic separation wash station
800.
[0274] Temperature ramping stations 700 can be a bottle neck in the
processing of a number of MTUs through the chemistry deck 200. It
may be possible to use underutilized MTU stations 676 in one or
more of the incubators in which temperature sensitivity is of less
concern. For example, the active temperature binding process which
occurs within the active temperature and pre-read cool-down
incubator 602 at about 40.degree. C. is not as temperature
sensitive as the other incubators, and up to fifteen (15) of the
incubator's thirty (30) MTU stations 676 may be unused at any given
time. As presently contemplated, the chemistry deck has only about
eight ramp-up stations, or heaters. Accordingly, significantly more
MTUs can be preheated within the unused slots of the active
temperature and pre-read cool-down incubator 602 than within the
ramp-up stations 700. Moreover, using unused incubator slots
instead of heaters allows the omission of some or all of the
heaters, thus freeing up space on the chemistry deck.
Magnetic Separation Wash Stations
[0275] Turning to FIGS. 24-25, each magnetic separation wash
station 800 includes a module housing 802 having an upper section
801 and a lower section 803. Mounting flanges 805, 806 extend from
the lower section 803 for mounting the magnetic separation wash
station 800 to the datum plate 82 by means of suitable mechanical
fasteners. Locator pins 807 and 811 extend from the bottom of lower
section 803 of housing 802. Pins 807 and 811 register with
apertures (not shown) formed in the datum plate 82 to help to
locate the magnetic separation wash station 800 on the datum plate
82 before the housing 802 is secured by fasteners.
[0276] A loading slot 804 extends through the front wall of the
lower section 803 to allow a transport mechanism (e.g. 502) to
place an MTU 160 into and remove an MTU 160 from the magnetic
separation station 800. A tapered slot extension 821 surrounds a
portion of the loading slot 804 to facilitate MTU insertion through
the slot 804. A divider 808 separates the upper section 801 from
the lower section 803.
[0277] A pivoting magnet moving structure 810 is attached inside
the lower section 803 so as to be pivotable about point 812. The
magnet moving structure 810 carries permanent magnets 814, which
are positioned on either side of an MTU slot 815 formed in the
magnet moving structure 810. Preferably five magnets, one
corresponding to each individual receptacle vessel 162 of the MTU
160, are held in an aligned arrangement on each side of the magnet
moving structure 810. The magnets are preferably made of
neodymium-iron-boron (NdFeB), minimum grade n-35 and have preferred
dimensions of 0.5 inch width, 0.3 inch height, and 0.3 inch depth.
An electric actuator, generally represented at 816, pivots the
magnet moving structure 810 up and down, thereby moving the magnets
814. As shown in FIG. 25, actuator 816 preferably comprises a
rotary stepper motor 819 which rotates a drive screw mechanism
coupled to the magnet moving structure 810 to selectively raise and
lower the magnet moving structure 810. Motor 819 is preferably an
HSI linear stepper actuator, model number 26841-05, available from
Haydon Switch and Instrument, Inc. of Waterbury, Conn.
[0278] A sensor 818, preferably an optical slotted sensor, is
positioned inside the lower section 803 of the housing for
indicating the down, or "home", position of the magnet moving
structure 810. Sensor 818 is preferably an Optek Technology, Inc.,
model number OPB980T11, available from Optek Technology, Inc. of
Carrollton, Tex. Another sensor 817, also preferably an Optek
Technology, Inc., model number OPB980T11, optical slotted sensor,
is preferably provided to indicate the up, or engaged, position of
the magnet moving structure 810.
[0279] An MTU carrier unit 820 is disposed adjacent the loading
slot 804, below the divider 808, for operatively supporting an MTU
160 disposed within the magnetic separation wash station 800.
Turning to FIG. 26, the MTU carrier unit 820 has a slot 822 for
receiving the upper end of an MTU 160. A lower fork plate 824
attaches to the bottom of the carrier unit 820 and supports the
underside of the connecting rib structure 164 of the MTU 160 when
slid into the carrier unit 820 (see FIGS. 27 and 28). A spring clip
826 is attached to the carrier unit 820 with its opposed prongs
831, 833 extending into the slot 822 to releasably hold the MTU
within the carrier unit 820.
[0280] An orbital mixer assembly 828 is coupled to the carrier unit
820 for orbitally mixing the contents of an MTU held by the MTU
carrier unit 820. The orbital mixer assembly 828 includes a stepper
motor 830 mounted on a motor mounting plate 832, a drive pulley 834
having an eccentric pin 836, an idler pulley 838 having an
eccentric pin 840, and a belt 835 connecting drive pulley 834 with
idler pulley 838. Stepper motor 830 is preferably a VEXTA, model
number PK245-02A, available from Oriental Motors Ltd. of Tokyo,
Japan, and belt 835 is preferably a timing belt, model number A
6G16-170012, available from SDP/SI of New Hyde Park, N.Y. As shown
in FIGS. 25 and 26, eccentric pin 836 fits within a slot 842 formed
longitudinally in the MTU carrier unit 820. Eccentric pin 840 fits
within a circular aperture 844 formed in the opposite end of MTU
carrier unit 820. As the motor 830 turns the drive pulley 834,
idler pulley 838 also rotates via belt 835 and the MTU carrier unit
820 is moved in a horizontal orbital path by the eccentric pins
836, 840 engaged with the apertures 842, 844, respectively, formed
in the carrier unit 820. The rotation shaft 839 of the idler pulley
838 preferably extends upwardly and has a transverse slot 841
formed therethrough. An optical slotted sensor 843 is disposed at
the same level as the slot 841 and measures the frequency of the
idler pulley 838 via the sensor beam intermittently directed
through slot 841 as the shaft 839 rotates. Sensor 843 is preferably
an Optek Technology, Inc., model number OPB980T11, sensor,
available from Optek Technology, Inc. of Carrollton, Tex.
[0281] Drive pulley 834 also includes a locator plate 846. Locator
plate 846 passes through slotted optical sensors 847, 848 mounted
to a sensor mounting bracket 845 extending from motor mounting
plate 832. Sensors 847, 848 are preferably Optek Technology, Inc.,
model number OPB980T11, sensors, available from Optek Technology,
Inc. of Carrollton, Tex. Locator plate 846 has a plurality of
circumferentially spaced axial openings formed therein which
register with one or both sensors 847, 848 to indicate a position
of the orbital mixer assembly 828, and thus a position of the MTU
carrier unit 820.
[0282] Returning to FIG. 24, wash buffer solution delivery tubes
854 connect to fittings 856 and extend through a top surface of the
module housing 802. Wash buffer delivery tubes 854 extend through
the divider 808 via fittings 856, to form a wash buffer delivery
network.
[0283] As shown in FIGS. 27 and 28, wash buffer dispenser nozzles
858 extending from the fittings 856 are disposed within the divider
808. Each nozzle is located above a respective receptacle vessel
162 of the MTU 160 at a laterally off-center position with respect
to the receptacle vessel 162. Each nozzle includes a
laterally-directed lower portion 859 for directing the wash buffer
into the respective receptacle vessel from the off-center position.
Dispensing fluids into the receptacle vessels 162 in a direction
having a lateral component can limit splashing as the fluid runs
down the sides of the respective receptacle vessels 162. In
addition, the laterally directed fluid can rinse away materials
clinging to the sides of the respective receptacle vessels 162.
[0284] As shown in FIGS. 24 and 25, aspirator tubes 860 extend
through a tube holder 862, to which the tubes 860 are fixedly
secured, and extend through openings 861 in the divider 808. A tube
guide yoke 809 (see FIG. 26) is attached by mechanical fasteners to
the side of divider 808, below openings 861. Aspirator hoses 864
connected to the aspirator tubes 860 extend to the vacuum pump 1162
(see FIG. 52) within the analyzer 50, with aspirated fluid drawn
off into a fluid waste container carried in the lower chassis 1100.
Each of the aspirator tubes 860 has a preferred length of 12 inches
with an inside diameter of 0.041 inches.
[0285] The tube holder 862 is attached to a drive screw 866
actuated by a lift motor 868. Lift motor 868 is preferably a VEXTA,
model number PK245-02A, available from Oriental Motors Ltd. of
Tokyo, Japan, and the drive screw 866 is preferably a ZBX series
threaded anti-backlash lead screw, available from Kerk Motion
Products, Inc. of Hollis, New Hampshire. The tube holder 862 is
attached to a threaded sleeve 863 of the drive screw 866. Rod 865
and slide rail 867 function as a guide for the tube holder 862.
Z-axis sensors 829, 827 (slotted optical sensors) cooperate with a
tab extending from threaded sleeve 863 to indicate top and bottom
of stroke positions of the aspirator tubes 860. The Z-axis sensors
are preferably Optek Technology, Inc., model number OPB980T11,
sensors, available from Optek Technology, Inc. of Carrollton,
Tex.
[0286] Cables bring power and control signals to the magnetic
separation wash station 800, via a connector 870.
[0287] The magnet moving structure 810 is initially in a down
position (shown in phantom in FIG. 25), as verified by the sensor
818, when the MTU 160 is inserted into the magnetic separation wash
station 800 through the insert opening 804 and into the MTU carrier
unit 820. When the magnet moving structure 810 is in the down
position, the magnetic fields of the magnets 814 will have no
substantial effect on the magnetically responsive particles
contained in the MTU 160. In the present context, "no substantial
effect" means that the magnetically responsive particles are not
drawn out of suspension by the attraction of the magnetic fields of
the magnets 814. The orbital mixer assembly 828 moves the MTU
carrier unit 820 a portion of a complete orbit so as to move the
carrier unit 820 and MTU 160 laterally, so that each of the tiplets
170 carried by the tiplet holding structures 176 of the MTU 160 is
aligned with each of the aspiration tubes 860, as shown in FIG. 28.
The position of the MTU carrier unit 820 can be verified by the
locator plate 846 and one of the sensors 847, 848. Alternatively,
the stepper motor 830 can be moved a known number of steps to place
the MTU carrier unit 820 in the desired position, and one of the
sensors 847, 848 can be omitted.
[0288] The tube holder 862 and aspirator tubes 860 are lowered by
the lift motor 868 and drive screw 866 until each of the aspirator
tubes 860 frictionally engages a tiplet 170 held in an associated
carrying structure 176 on the MTU 160.
[0289] As shown in FIG. 25A, the lower end of each aspirator tube
860 is characterized by a tapering, step construction, whereby the
tube 860 has a first portion 851 along most of the extent of the
tube, a second portion 853 having a diameter smaller than that of
the first portion 851, and a third portion 855 having a diameter
smaller than that of the second portion 853. The diameter of the
third portion 855 is such as to permit the end of the tube 860 to
be inserted into the flared portion 181 of the through hole 180 of
the tiplet 170 and to create an interference friction fit between
the outer surface of third portion 855 and the two annular ridges
183 (see FIG. 59) that line the inner wall of hole 180 of tiplet
170. An annular shoulder 857 is defined at the transition between
second portion 853 and third portion 855. The shoulder 857 limits
the extent to which the tube 860 can be inserted into the tiplet
170, so that the tiplet can be stripped off after use, as will be
described below.
[0290] The tiplets 170 are at least partially electrically
conductive, so that the presence of a tiplet 170 on an aspirator
tube 860 can be verified by the capacitance of a capacitor
comprising the aspirator tubes 860 as one half of the capacitor and
the surrounding hardware of the magnetic separation wash station
800 as the other half of the capacitor. The capacitance will change
when the tiplets 170 are engaged with the ends of the aspirator
tubes 860.
[0291] In addition, five optical slotted sensors (not shown) can be
strategically positioned above the divider 808 to verify the
presence of a tiplet 170 on the end of each aspirator tube 860.
Preferred "tiplet-present" sensors are Optek Technology, Inc.,
model number OPB930W51, sensors, available from Optek Technology,
Inc. of Carrollton, Tex. A tiplet 170 on the end of an aspirator
tube 860 will break the beam of an associated sensor to verify
presence of the tiplet 170. If, following a tiplet pick-up move,
tiplet engagement is not verified by the tiplet present sensors for
all five aspirator tubes 860, the MTU 160 must be aborted. The
aborted MTU is retrieved from the magnetic separation wash station
800 and sent to the deactivation queue 750 and ultimately
discarded.
[0292] After successful tiplet engagement, the orbital mixer
assembly 828 moves the MTU carrier unit 820 back to a fluid
transfer position shown in FIG. 27 as verified by the locator plate
846 and one or both of the sensors 847, 848.
[0293] The magnet moving structure 810 is then raised to the up
position shown in FIG. 24 so that the magnets 814 are disposed
adjacent opposite sides of the MTU 160. With the contents of the
MTU subjected to the magnetic fields of the magnets 814, the
magnetically responsive particles bound indirectly to the target
nucleic acids will be drawn to the sides of the individual
receptacle vessels 162 adjacent the magnets 814. The remaining
material within the receptacle vessels 162 should be substantially
unaffected, thereby isolating the target nucleic acids. The magnet
moving structure 810 will remain in the raised position for an
appropriate dwell time, as defined by the assay protocol and
controlled by the assay manager program, to cause the magnetic
particles to adhere to the sides of the respective receptacle
vessels 162.
[0294] The aspirator tubes are then lowered into the receptacle
vessels 162 of the MTU 160 to aspirate the fluid contents of the
individual receptacle vessels 162, while the magnetic particles
remain in the receptacle vessels 162, adhering to the sides
thereof, adjacent the magnets 814. The tiplets 170 at the ends of
the aspirator tubes 860 ensure that the contents of each receptacle
vessel 162 do not come into contact with the sides of the aspirator
tubes 860 during the aspirating procedure. Because the tiplets 170
will be discarded before a subsequent MTU is processed in the
magnetic separation wash station 800, the chance of
cross-contamination by the aspirator tubes 860 is minimized.
[0295] The electrically conductive tiplets 170 can be used in a
known manner for capacitive fluid level sensing within the
receptacle vessels 162 of the MTUs. The aspirator tubes 860 and the
conductive tiplets 170 comprise one half of a capacitor, the
surrounding conductive structure within the magnetic separation
wash station comprises the second half of the capacitor, and the
fluid medium between the two halves of the capacitor constitutes
the dielectric. Capacitance changes due to a change in the nature
of the dielectric can be detected.
[0296] The capacitive circuitry of the aspirator tubes 860 can be
arranged so that all five aspirator tubes 860 operate as a single
gang level-sensing mechanism. As a gang level-sensing mechanism,
the circuitry will only determine if the fluid level in any of the
receptacle vessels 162 is high, but cannot determine if the fluid
level in one of the receptacle vessels is low. In other words, when
any of the aspirator tubes 860 and its associated tiplet 170
contacts fluid material within a receptacle vessel, capacitance of
the system changes due to the change in the dielectric. If the
Z-position of the aspirator tubes 860 at which the capacitance
change occurs is too high, then a high fluid level in at least one
receptacle vessel is indicated, thus implying an aspiration
failure. On the other hand, if the Z-position of the aspirator
tubes at which the capacitance change occurs is correct, the
circuitry cannot differentiate between aspirator tubes, and,
therefore, if one or more of the other tubes has not yet contacted
the top of the fluid, due to a low fluid level, the low fluid level
will go undetected.
[0297] Alternatively, the aspirator tube capacitive circuitry can
be arranged so that each of the five aspirator tubes 860 operates
as an individual level sensing mechanism.
[0298] With five individual level sensing mechanisms, the
capacitive level sensing circuitry can detect failed fluid
aspiration in one or more of the receptacle vessels 162 if the
fluid level in one or more of the receptacle vessels is high.
Individual capacitive level sensing circuitry can detect failed
fluid dispensing into one or more of the receptacle vessels 162 if
the fluid level in one or more of the receptacle vessels is low.
Furthermore, the capacitive level sensing circuitry can be used for
volume verification to determine if the volume in each receptacle
vessel 162 is within a prescribed range. Volume verification can be
performed by stopping the descent of the aspirator tubes 860 at a
position above expected fluid levels, e.g. 110% of expected fluid
levels, to make sure none of the receptacle vessels has a level
that high, and then stopping the descent of the aspirator tubes 860
at a position below the expected fluid levels, e.g. 90% of expected
fluid levels, to make sure that each of the receptacle vessels has
a fluid level at least that high.
[0299] Following aspiration, the aspirator tubes 860 are raised,
the magnet moving structure 810 is lowered, and a prescribed volume
of wash buffer is dispensed into each receptacle vessel 162 of the
MTU 160 through the wash buffer dispenser nozzles 858. To prevent
hanging drops of wash buffer on the wash buffer dispenser nozzles
858, a brief, post-dispensing air aspiration is preferred.
[0300] The orbital mixer assembly 828 then moves the MTU carriers
820 in a horizontal orbital path at high frequency to mix the
contents of the MTU 160. Mixing by moving, or agitating, the MTU in
a horizontal plane is preferred so as to avoid splashing the fluid
contents of the MTU and to avoid the creation of aerosols.
Following mixing, the orbital mixer assembly 828 stops the MTU
carrier unit 820 at the fluid transfer position.
[0301] To further purify the targeted nucleic acids, the magnet
moving structure 810 is again raised and maintained in the raised
position for a prescribed dwell period. After magnetic dwell, the
aspirator tubes 860 with the engaged tiplets 170 are lowered to the
bottoms of the receptacle vessels 162 of the MTU 160 to aspirate
the test specimen fluid and wash buffer in an aspiration procedure
essentially the same as that described above.
[0302] One or more additional wash cycles, each comprising a
dispense, mix, magnetic dwell, and aspirate sequence, may be
performed as defined by the assay protocol. Those skilled in the
art of nucleic acid-based diagnostic testing will be able to
determine the appropriate magnetic dwell times, number of wash
cycles, wash buffers, etc. for a desired target capture
procedure.
[0303] While the number of magnetic separation wash stations 800
can vary, depending on the desired throughput, analyzer 50
preferably includes five magnetic separation wash stations 800, so
that a magnetic separation wash procedure can be performed on five
different MTUs in parallel.
[0304] After the final wash step, the magnet moving structure 810
is moved to the down position and the MTU 160 is removed from the
magnetic separation wash station 800 by the left-side transport
mechanism 502 and is then placed into the left orbital mixer
552.
[0305] After the MTU 160 is removed from the wash station, the
tiplets 170 are stripped from the aspiration tubes 860 by a
stripper plate 872 located at the bottom of the lower section 803
of the housing 802.
[0306] The stripper plate 872 has a number of aligned stripping
holes 871 corresponding in number to the number of aspiration tubes
860, which is five in the preferred embodiment. As shown in FIGS.
29A to 29D, each stripping hole 871 includes a first portion 873, a
second portion 875 smaller than first portion 873, and a bevel 877
surrounding portions 873 and 875. The stripper plate 872 is
oriented in the bottom of the housing 802 so that the small portion
875 of each stripping hole 871 is generally aligned with each
associated aspiration tube 860, as shown in FIG. 29A. The
aspiration tubes 860 are lowered so that the tiplet 170 at the end
of each aspirator tube 860 engages the stripping hole 871. Small
portion 875 is too small to accommodate the diameter of a tiplet
170, so the bevel 877 directs the tiplet 170 and the aspirator tube
860 toward the larger portion 873, as shown in FIG. 29B. The
aspirator tubes 860 are made of an elastically flexible material,
preferably stainless steel, so that, as the aspirator tubes 860
continue to descend, the beveled portion 877 causes each of
aspirator tubes 860 to deflect laterally. The small portion 875 of
the stripping hole 871 can accommodate the diameter of the
aspirator tube 860, so that after the rim 177 of the tiplet 170
clears the bottom of stripping hole 871, each of the aspirator
tubes 860 snaps, due to its own resilience, into the small portion
875 of the stripping hole 871 as shown in FIG. 29C. The aspirator
tubes 860 are then raised, and the rim 177 of each tiplet 170
engages the bottom peripheral edge of the small portion 875 of
stripping hole 871. As the aspirator tubes 860 ascend further, the
tiplets 170 are pulled off the aspirator tubes 860 by the stripping
holes 871 (see FIG. 29D). The stripped tiplets 170 are directed by
a chute into a solid waste container, such as the tiplet waste bin
1134.
[0307] The capacitance of the aspiration tubes 860 is sampled to
verify that all tiplets 170 have been stripped and discarded. The
stripping step can be repeated if necessary.
[0308] An alternate stripper plate 882 is shown in FIGS. 31A to
31C. Stripper plate 882 includes a number of stripping holes 881
corresponding to the number of aspirator tubes 860, which is five
in the preferred embodiment. Each stripping hole 881 includes a
through-hole 883 surrounded by a bevelled countersink 887. A pair
of tangs 885 extend laterally from diametrically opposed positions
below the through-hole 883. Tangs 885 are preferably made from a
spring steel and include a v-notch 886 at their ends.
[0309] As an aspirator tube 860 with a tiplet 170 disposed on its
end is lowered toward stripping hole 881, bevelled portion 887
ensures that any misaligned tubes are directed into the
through-hole 883. The spacing between the ends of the opposed tangs
885 is less than the diameter of the tiplet 170, so as the
aspirator tube 860 and tiplet 170 are lowered, the tiplet engages
the tangs 885, causing them to deflect downwardly as the tiplet 170
is forced between tangs 885. When the aspirator tubes 860 are
raised, the notches 886 of the tangs 885 grip the relatively soft
material of the tiplet 170, thus preventing upward relative
movement of the tiplet 170 with respect to the tangs 885. As the
tubes continue to ascend, the tangs 885 pull the tiplet 170 off the
tube 860. When the aspirator tubes 860 are subsequently lowered to
strip a subsequent set of tiplets, the tiplet held between the
tangs from the previous stripping is pushed through the tangs by
the next tiplet and is directed toward waste bin 1134 (see FIG. 52)
located in the lower chassis 1100 generally below the five magnetic
separation wash stations 800.
[0310] Still another alternate, and the presently preferred,
stripper plate 1400 is shown in FIGS. 30A-30D. Stripper plate 1400
includes five stripper cavities 1402, each including an initial
frusto-conical portion 1404. The frusto-conical portion 1404 tapers
down to a neck portion 1406 which connects to an enlarged straight
section 1408. Straight section 1408 is offset with respect to the
center of neck portion 1406, so that one side of the straight
section 1408 is flush with a side of the neck portion 1406, and an
opposite side of the straight section 1408 is offset from and
undercuts the side of the neck portion 1406, thereby forming a
ledge 1414. Following the straight section 1408, a sloped portion
1410 is provided on a side of the stripper cavity 1402 opposite the
ledge 1414. Sloped portion 1410 tapers inwardly toward a bottom
opening 1412.
[0311] As an aspirator tube 860 with a tiplet 170 on its end is
moved toward the stripper cavity 1402, the frusto-conical portion
1404 directs the tiplet 170 and tube 860 toward the neck portion
1406. The aspirator tube 860 continues to descend, and the tiplet
170 enters the straight section 1408 as the rim 177 of the tiplet
170 clears the bottom of the frusto-conical portion 1404 and passes
through the neck portion 1406.
[0312] If the aspirator tube 860 and the stripper cavity 1402 are
in proper, preferred alignment, a portion of the rim 177 of the
tiplet 170 will be disposed below the ledge 1414 of the stripper
cavity 1402 when the tiplet 170 has moved through the neck portion
1406 and into the straight section 1408. To ensure that a portion
of the rim 177 will be disposed beneath the ledge 1414, the tiplet
170 engages the lower sloped portion 1410 as the aspirator tube 860
descends further to urge the aspirator tube laterally to direct the
tiplet 170 below the ledge 1414.
[0313] The annular shoulder 857 (see FIG. 25A) formed at the bottom
of the aspirator tube 860 ensures that the tube 860 is not forced
further into the through hole 180 of the tiplet 170 as the tube 860
is lowered into the stripper cavity 1402. The aspirator tube 860
then ascends, and the ledge 1414 catches the rim 177 and strips the
tiplet 170 off the tube 860. The stripped tiplet 170 falls through
bottom opening 1412 and into the waist bin 1134 in the lower
chassis 1100 (see FIG. 52).
[0314] With each of the stripper plates described above, the
position of the tiplet-stripping elements are not all the same. For
example, the ledges 1414 of the stripper cavities 1402 of the
stripper plate 1400 are not at the same height throughout all the
cavities. Preferably, three tiplet-stripping elements are at one
height, and two tiplet-stripping elements are at a slightly
different height above or below the other three elements. The
result of the offset tiplet-stripping elements is that the static
friction of the tiplet 170 on the end of the aspirator tube 860
need not be overcome, or broken, for all five tubes 860 at once. As
the aspirator tubes 860 begin to ascend, static friction of the
tiplets 170 is broken for one set (two or three) of aspirator tubes
860 first, and then, as the tubes 860 continue to ascend, static
friction of the tiplets 170 is broken for the remaining tubes 860.
By not breaking static friction of the tiplets 170 for all five
aspirator tubes 860 at once, the loads to which the tube holder
862, drive screw 866, threaded sleeve 863, and lift motor 868 are
subjected are kept to a lower level.
Orbital Mixers
[0315] The left orbital mixer 552 (and the right orbital mixer
550), as shown in FIGS. 32-34, are constructed and operate in the
same manner as the lower housing section 803 and the orbital mixer
assembly 828 of the magnetic separation wash stations 800 described
above. Specifically, the orbital mixer 550 (552) includes a housing
554, including a front plate 551, a back plate 559, and mounting
flanges 555, 556, for mounting the orbital mixer 550 (552) to the
datum plate 82. An insert opening 557 is formed in a front edge of
the housing 554. An MTU carrier 558 has a fork plate 560 attached
to the bottom thereof and an MTU-retaining clip 562 attached to a
back portion of the carrier 558 with opposed prongs of the clip 562
extending into an inner cavity of the carrier 558 that accommodates
the MTU. An orbital mixer assembly 564 includes a drive motor 566
mounted to a motor mounting plate 567, a drive wheel 568 having an
eccentric pin 570, an idler wheel 572 having an eccentric pin 573,
and a belt 574. Drive motor 566 is preferably a stepper motor, and
most preferably a VEXTA, model number PK245-02A, available from
Oriental Motors Ltd. of Tokyo, Japan. Belt 574 is preferably a
timing belt, model number A 6G16-170012, available from SDP/SI of
New Hyde Park, N.Y. The orbital mixer assembly 564 is coupled to
the MTU carrier 558 through the eccentric pins 570, 573 to move the
MTU carrier 558 in an orbital path to agitate the contents of the
MTU. The drive wheel 568 includes a locator plate 576, which, in
conjunction with sensor 578 attached to sensor mounting bracket
579, verifies the proper positioning of the MTU carrier 558 for
inserting an MTU 160 into the orbital mixer 552 (550) and
retrieving an MTU 160 from the orbital mixer. Sensor 578 is
preferably an Optek Technology, Inc., model number OPB980T11,
sensor, available from Optek Technology, Inc. of Carrollton,
Tex.
[0316] A top plate 580 is attached atop housing 554. Top plate 580
of the left orbital mixer 552 includes a number of tube fittings
582, preferably five, to which are coupled a like number of
flexible delivery tubes (not shown) for delivering a fluid from a
bulk fluid container to an MTU 160 located within the mixer via
dispenser nozzles 583. Top plate 580 also includes a plurality of
pipette openings 581, corresponding in number to the number of
individual receptacle vessels 162 comprising a single MTU 160,
which is preferably five.
[0317] With the MTU 160 held stationary in the left orbital mixer
552, pipette unit 480 of the left pipette assembly 470 transfers a
prescribed volume of amplification reagent from a container within
the reagent cooling bay 900 into each receptacle vessel 162 of the
MTU 160 through the pipette openings 581. The amplification reagent
used will depend upon the amplification procedure being followed.
Various amplification procedures are well known to those skilled in
the art of nucleic acid-based diagnostic testing, a number of which
are discussed in the background section above.
[0318] Next, the contents of the MTU are mixed by the orbital mixer
assembly 564 of the orbital mixer 552 to ensure proper exposure of
the target nucleic acid to amplification reagent. For a desired
amplification procedure, those skilled in the art of nucleic
acid-based diagnostic testing will be able to determine the
appropriate components and amounts of an amplification reagent, as
well as mix frequencies and durations.
[0319] After pipetting amplification reagent into the MTU 160, the
pipette unit 480 is moved to a rinse basin (described below) on the
processing deck 200, and pipette unit 480 is washed by running
distilled water through probe 481. The distilled water is pumped
from bottle 1140 in the lower chassis 1100, and the purge water is
collected in a liquid waste container 1128 in the lower chassis
1100.
[0320] After mixing the contents of the MTU 160, a layer of
silicone oil is dispensed into each receptacle vessel through the
dispenser nozzles 583. The layer of oil, pumped from bottles 1168
in the lower chassis 1100, helps prevent evaporation and splashing
of the fluid contents of the MTU 160 during subsequent manipulation
and incubation of the MTU 160 and its contents.
Reagent Cooling Bay
[0321] The reagent cooling bay 900 will now be described.
[0322] Referring to FIGS. 35-39, the reagent cooling bay 900
includes an insulating jacket 902 fitted around a cylindrical
housing 904, preferably made from aluminum. A cover 906, preferably
made of Delrin, sits atop housing 904 with a registration tab 905
of cover 906 fitting within slot 907 in housing 904 to ensure
proper orientation of the cover 906 An optical sensor may be
provided proximate to or within slot 907 for verifying that tab 905
is seated within slot 907. Alternatively, an optical sensor
assembly 909 can be secured to an edge of an upper rim of the
housing 904 for verifying cover placement. The optical sensor
assembly 909 cooperates with a sensor-tripping structure (not
shown) on the cover 906 to verify that the cover is in place.
Optical sensor assembly 909 preferably includes an Optek
Technology, Inc. slotted optical sensor, model number OPB980T11,
available from Optek Technology, Inc. of Carrollton, Tex. The cover
906 also includes pipette openings 908 through which pipette units
480, 482 can access reagent containers within the cooling bay
900.
[0323] The housing 904 is attached to a floor plate 910, and the
floor plate 910 is attached to the datum plate 82 by means of
suitable mechanical fasteners extending through openings formed in
mounting flanges 911 spaced about the periphery of the floor plate
910. Cooling units 912, preferably two, are attached to floor plate
910. Each cooling unit 912 comprises a thermoelectric module 914
attached cool-side-up to the bottom surface of floor plate 910.
Thermoelectric modules available from Melcor, Inc. of Trenton,
N.J., model number CP1.4-127-06L, provide the desired cooling
capacity. A heat sink 916, including a plurality of
heat-dissipating fins 915, is attached to, or may be integral with,
the bottom surface of floor plate 910, directly below the
thermoelectric module 914. A fan unit 918 is attached in a position
to drain heat away from heat sink 916. Fan units 918 are preferably
Orix fans, model number MD825B-24, available from Oriental Motors
Ltd. of Tokyo, Japan. Together, the cooling units 912 cool the
interior of the housing 904 to a prescribed temperature for the
benefit of temperature-sensitive reagents (e.g., enzymes) stored
within the bay 900.
[0324] Two temperature sensors (only one temperature sensor 920 is
shown) are disposed within the cooling bay 900 housing 904 for
monitoring and controlling the interior temperature thereof. The
temperature sensors are preferably thermistors (10 KOhm at
25.degree. C.), and YSI 44036 series thermistors available from
YSI, Inc. of Yellow Springs, Ohio are most preferred. YSI
thermistors are preferred because of their high accuracy and the
.+-.0.1.degree. C. interchangeability provided by YSI thermistors
from one thermistor to another. One of the sensors is a primary
temperature control sensor, and the other is a temperature
monitoring sensor. On the basis of the temperature indications from
the primary control sensor, the embedded controller adjusts power
to the thermoelectric modules 914 and/or power to the fan units 918
to control cooling bay temperature. The temperature monitoring
sensor provides a verification check of the primary temperature
control sensor.
[0325] As shown in FIG. 38, container tray 922 is a one-piece
turntable structure with bottle-holding cavities 924 sized and
shaped to receive and hold specific reagent bottles 925. A drive
system for container tray 922 includes a motor 926, a small pulley
931 on the shaft of motor 926, a belt 928, a pulley 930, and a
shaft 932.
(a VEXTA stepper motor, model number PK265-02A, available from
Oriental Motor Co., Ltd. of Tokyo, Japan, and an SDP timing belt,
GT.RTM. Series, available from SDP/SI of New Hyde Park, N.Y., are
preferred). Motor 926 and cooling units 912 extend through openings
(not shown) formed in the datum plate 82 and extend below the floor
plate 910.
[0326] Container tray 922 may include a central, upstanding handle
923 to facilitate installation of the tray 922 into and removal of
the tray 922 from the housing 904. A top portion 933 of shaft 932
extends through floor plate 910 and is received by a mating
aperture (not shown) formed in the bottom of the tray 922. A sensor
940 extending up through the floor plate 910 and into the housing
904 verifies that tray 922 is in place within the housing 904.
Sensor 940 is preferably a capacitive proximity sensor available
from Advanced Controls, Inc., of Bradenton, Fla., model number
FCP2.
[0327] A position encoder 934 (preferably a slotted disk) in
conjunction with an optical sensor 935 may be used to detect the
position of the container tray 922, so that a specific reagent
bottle 925 may be aligned under the pipette openings 908 in the
cover 906.
[0328] As shown in FIG. 37, a preferred alternative to the position
encoder 934 and optical sensor 935 includes four slotted optical
sensors 937 (only two sensors are visible in FIG. 36) provided
inside the housing 904 along with a flag pin (not shown) extending
from the bottom of container tray 922. One sensor is provided for
each quadrant of the container tray 922, and the flag trips one of
the four sensors to indicate which quadrant of the container tray
922 is aligned with the pipette openings 908. Sensors 937 are
preferably Optek Technology, Inc. sensors, model number OPB980T11,
available from Optek Technology, Inc. of Carrollton, Tex.
[0329] A preferred alternative to the one-piece container tray 922
shown in FIG. 38 is a modular tray 1922 shown in FIGS. 35 and 39.
Tray 1922 includes a circular base plate 1926 and an upstanding
handle post 1923 attached to a central portion thereof. Modular
pieces 1930 having bottle-holding cavities 1924 are preferably
connected to one another and to the base plate 1926 by pins 1928
and screws (not shown) to form the circular tray 1922. Other means
of securing the modular pieces 1930 may be employed in the
alternative to pins 1928 and screws. The modular pieces 1930 shown
in the figures are quadrants of a circle, and thus, of course, four
such pieces 1930 would be required to complete the tray 1922.
Although quadrants are preferred, the modular pieces may however be
sectors of various sizes, such as, for example, 1/2 of a circle or
1/8 of a circle.
[0330] Alphanumeric bottle location labels 1940 are preferably
provided on the base plate 1926 to identify positions within the
tray 1922 for reagent containers. The preferred label scheme
includes an encircled letter-number pair comprising a leading
letter A, E, P, or S with a trailing number 1, 2, 3, or 4, The
letters A, E, P, and S, designate amplification reagent, enzyme
reagent, probe reagent, and select reagent, respectively,
corresponding to the preferred mode of use of the analyzer 50, and
the numbers 1-4 designate a quadrant of the tray 1922. Each modular
piece 1930 includes a circular hole 1934 at the bottom of each
bottle-holding cavity 1924. The holes 1934 align with the bottle
location labels 1940, so that the labels 1940 can be seen when the
modular pieces 1930 are in place on the base plate 1926.
[0331] The modular pieces 1930 of the container tray 1922 are
configured to accommodate reagent containers of different sizes
corresponding to reagent quantities sufficient for performing two
hundred fifty (250) assays or reagent quantities sufficient for
performing five hundred (500) assays. Four 250-assay modular
quadrants permit the reagent cooling bay to be stocked for 1000
assays, and four 500-assay modular quadrants permit the reagent
cooling bay to be stocked for 2000 assays. Modular quadrants for
250 or 500 assay reagent kits can be mixed and matched to configure
the container tray for accommodating various numbers of a single
assay type or various numbers of multiple different assay
types.
[0332] An insulation pad 938 is disposed between the container tray
922 and the floor plate 910. Power, control, temperature, and
position signals are provided to and from the reagent cooling bay
900 by a connector 936 and a cable (not shown) linked to the
embedded controller of the analyzer 50.
[0333] A bar code scanner 941 is mounted to an upstanding scanner
mounting plate 939 attached to floor plate 910 in front of an
opening 942 formed in a side-wall of the cooling bay 900. The bar
code scanner 941 is able to scan bar code information from each of
the reagent containers carried on the container tray 922. As shown
in FIG. 39, longitudinal slots 1932 are formed along the
bottle-holding cavities 1924, and bar code information disposed on
the sides of the reagent container held in the bottle-holding
cavities 1924 can be align with the slots 1932 to permit the bar
code scanner 941 to scan the bar code information. A preferred bar
code scanner is available from Microscan of Newbury Park, Calif.
under model number FTS-0710-0001.
[0334] Pipette rinse basins 1942, 1944 are attached to the side of
the housing 904. Each rinse basin 1942, 1944 provides an enclosure
structure with a probe-receiving opening 1941, 1945, respectively,
formed in a top panel thereof and a waste drain tube 1946, 1948,
respectively, connected to a bottom portion thereof. A probe of a
pipette unit can be inserted into the rinse basin 1942, 1944
through the probe-receiving opening 1941, 1945, and a wash and/or
rinse fluid can be passed through the probe and into the basin.
Fluid in the rinse basin 1942, 1944 is conducted by the respective
waste drain tube 1946, 1948 to the appropriate waste fluid
container in the lower chassis 1100. In the preferred arrangement
and mode of operation of the analyzer 50, probe 481 of pipette unit
480 is rinsed in rinse basin 1942, and probe 483 of pipette unit
482 is rinsed in rinse basin 1944.
[0335] After the amplification reagent and oil are added to the
receptacle vessels 162 of MTU 160 in the left orbital mixer 552,
the left-side transport mechanism 502 retrieves the MTU 160 from
the left orbital mixer 552 and moves the MTU 160 to an available
temperature ramp-up station 700 that is accessible to the left-side
transport mechanism 502, i.e. on the left side of the chemistry
deck 200, to increase the temperature of the MTU 160 and its
contents to about 60.degree. C.
[0336] After sufficient ramp-up time in the ramp-up station 700,
the left-side transport mechanism 502 then moves the MTU 160 to the
target capture and annealing incubator 600. The left-side
distributor door 624 of the target capture and annealing incubator
600 opens, and the MTU carousel assembly 671 within the incubator
600 presents an empty MTU station 676 to permit the left-side
transport mechanism to insert the MTU into the incubator 600. The
MTU 160 and its contents are then incubated at about 60.degree. C.
for a prescribed incubation period. During incubation, the MTU
carousel assembly 671 may continually rotate within the incubator
600 as other MTUs 600 are removed from and inserted into the
incubator 600.
[0337] Incubating at 60.degree. C. in the annealing incubator 600
permits dissociation of the capture probe/target nucleic acid
hybridization complex from the immobilized polynucleotide present
in the assay solution. At this temperature, oligonucleotide primers
introduced from the reagent cooling bay 900 can hybridize to the
target nucleic acid and subsequently facilitate amplification of
the target nucleotide base sequence.
[0338] Following incubation, the MTU carousel assembly 671 within
incubator 600 rotates the MTU 160 to the left-side distributor door
624, the left side distributor door 624 opens, and the left-side
transport mechanism 502 retrieves the MTU 160 from the MTU carousel
assembly 671 of the target capture and annealing incubator 600. The
left-side transport mechanism 502 then moves the MTU 160 to, and
inserts the MTU 160 into, an available temperature ramp-down
station 700 that is accessible to the left-side transport mechanism
502. The temperature of the MTU 160 and its contents is decreased
to about 40.degree. C. in the ramp-down station. The MTU 160 is
then retrieved from the ramp-down station by the left-side
transport mechanism 502 and is moved to the active temperature and
pre-read cool-down incubator 602. The left-side distributor door
624 of the AT incubator 602 opens, and the MTU carousel assembly
671 within incubator 602 presents an empty MTU station 676, so that
the left-side transport mechanism 502 can insert the MTU into the
incubator 602. Within the active temperature and pre-read cool-down
incubator 602, the MTU is incubated at about 41.degree. C. for a
period of time necessary to stabilize the temperature of the
MTU.
[0339] From the active temperature and pre-read cool-down incubator
602, the MTU is moved by transport mechanism 502 to the
amplification incubator 604 in which the temperature of the MTU is
stabilized at 41.5.degree. C. The MTU carousel assembly 671 within
the amplification incubator 604 rotates to place the MTU at the
pipetting station below the pipette openings 662 formed in the
cover 611 (see, e.g., FIG. 19). The container tray 922 within the
reagent cooling bay 900 rotates to place the enzyme reagent
container below a pipette opening 908, and pipette unit 482 of
pipette assembly 470 transfers enzyme reagent from the reagent
cooling bay 900 to each of the receptacle vessels 162 of the MTU
160.
[0340] As explained above, pipette units 480, 482 use capacitive
level sensing to ascertain fluid level within a container and
submerge only a small portion of the end of the probe 481, 483 of
the pipette unit 480, 482 to pipette fluid from the container.
Pipette units 480, 482 preferably descend as fluid is drawn into
the respective probe 481, 483 to keep the end of the probe
submerged to a constant depth. After pipetting reagent into the
pipette unit 480 or 482, the pipette unit creates a minimum travel
air gap of 10 .mu.l in the end of the respective probe 481 or 483
to ensure no drips fall from the end of the probe.
[0341] After enzyme reagent is added to each receptacle vessel 162,
the MTU carousel assembly 671 of amplification incubator 604
rotates MTU 160 to the skewed disk linear mixer 634 within
amplification incubator 604 and the MTU 160 and its contents are
mixed as described above at about 10 Hz to facilitate exposure of
the target nucleic acid to the added enzyme reagent. The pipette
unit 482 is moved to rinse basin 1942, and the probe 483 is rinsed
by passing distilled water through it.
[0342] The MTU 160 is then incubated within amplification incubator
604 at about 41.5.degree. C. for a prescribed incubation period.
The incubation period should be sufficiently long to permit
adequate amplification of at least one target nucleotide base
sequence contained in one or more target nucleic acids which may be
present in the receptacle tubes 162. Although the preferred
embodiment is designed to facilitate amplification using a
transcription-mediated amplification (TMA) procedure, which is
discussed in the background section supra, practitioners will
easily appreciate those modifications necessary to perform other
amplification procedures using the analyzer 50. In addition, an
internal control sequence is preferably added at the beginning of
the assay to provide confirmation that the amplification conditions
and reagents were appropriate for amplification. Internal controls
are well known in the art and require no further discussion
here.
[0343] Following amplification incubation, the MTU 160 is moved by
the left-side transport mechanism 502 from the amplification
incubator 604 to an available ramp-up station 700 that is
accessible to the left-side transport mechanism 502 to bring the
temperature of the MTU 160 and its contents to about 60.degree. C.
The MTU 160 is then moved by the left-side transport mechanism 502
into the hybridization incubator 606. The MTU 160 is rotated to a
pipetting station in the hybridization incubator 606, and a probe
reagent from the reagent cooling bay 900 is pipetted into each
receptacle vessel, through openings 662 in the cover 611 of the
hybridization incubator 606, by the pipette unit 480. The probe
reagent includes chemiluminescent detection probes, and preferably
acridinium ester (AE)-labeled probes which can be detected using a
hybridization protection assay (HPA). Acridinium ester-labeled
probes and the HPA assay are well known in the art and are
described more fully in the background section supra. While
AE-labeled probes and the HPA assay are preferred, the analyzer 50
can be conveniently adapted to accommodate a variety of detection
methods and associated probes, both labeled and unlabeled.
Confirmation that detection probe has been added to the receptacle
vessels 162 can be accomplished using an internal control that is
able (or its amplicon is able) to hybridize to a probe in the probe
reagent, other than the detection probe, under the HPA assay
conditions extant in the receptacle vessels 162 in the
hybridization incubator 606. The label of this probe must be
distinguishable from the label of the detection probe.
[0344] After dispensing probe reagent into each of the receptacle
vessels 162 of the MTU 160, the pipette unit 480 moves to the
pipette rinse basin 1944, and the probe 481 of the pipette unit is
rinsed with distilled water.
[0345] The MTU carousel assembly 671 rotates the MTU 160 to the
skewed disk linear mixer 634 where the MTU 160 and its contents are
mixed, as described above, at about 14 Hz to facilitate exposure of
the target amplicon to the added detection probes. The MTU 160 is
then incubated for a period of time sufficient to permit
hybridization of the detection probes to the target amplicon.
[0346] After hybridization incubation, the MTU 160 is again rotated
within incubator 606 by the MTU carousel assembly 671 to the
pipetting position below the pipette openings 662. A selection
reagent stored in a container in the reagent cooling bay 900 is
pipetted into each receptacle vessel 162 by the pipette unit 480. A
selection reagent is used with the HPA assay and includes an
alkaline reagent that specifically hydrolyzes acridinium ester
label which is associated with unhybridized probe, destroying or
inhibiting its ability to chemiluminesce, while acridinium ester
label associated with probe hybridized to target amplicon (or
amplicon of the internal standard) is not hydrolyzed and can
chemiluminesce in a detectable manner under appropriate detection
conditions.
[0347] Following addition of the selection reagent to each of the
receptacle vessels 162 of the MTU 160, the pipette probe 481 of the
pipette unit 480 is rinsed with distilled water at the pipette
rinse basin 1944. The MTU 160 is rotated by the MTU carousel
assembly 671 within the incubator 606 to the skewed disk linear
mixer 634 and mixed, as described above, at about 13 Hz to
facilitate exposure of the target amplicon to the added selection
reagent. The MTU is then incubated in the incubator 606 for a
period of time sufficient to complete the selection process.
[0348] After selection incubation is complete, the left-side
transport mechanism 502 transfers the MTU 160 into an available
ramp-down station 700 that is accessible to the left-side transport
mechanism 502 to cool the MTU 160. After the MTU 160 is cooled, it
is retrieved from the ramp-down station by the left-side transport
mechanism 502 and is moved by the transport mechanism 502 into the
active temperature and pre-read cool-down incubator 602 to
stabilize the temperature of the MTU 160 at about 40.degree. C.
[0349] When a period sufficient to stabilize the temperature of the
MTU 160 has passed, the MTU carousel assembly 671 within active
temperature and pre-read cool-down incubator 602 rotates to present
the MTU 160 at the right-side distributor door of the incubator
602. The right-side distributor door 622 is opened and the MTU 160
is removed from active temperature and pre-read cool-down incubator
602 by right-side transport mechanism 500.
[0350] The right-side transport mechanism 500 moves the MTU to a
bar code scanner (not shown) which scans MTU bar code information
posted on the label-receiving surface 175 of the label-receiving
structure 174 of the MTU 160. The bar code scanner is preferably
attached to an outer wall of the housing of the luminometer 950. A
preferred bar code scanner is available from Opticon, Inc., of
Orangeburg, N.Y., as part number LHA1127RR1S-032. The scanner
verifies the total time of assay prior to entering the luminometer
950 by confirming the correct MTU at the correct assay time. From
the bar code reader, the right-side transport mechanism 500 moves
the MTU 160 to the luminometer 950.
[0351] In a preferred mode of operation, before the right-side
transport mechanism 500 moves the MTU 160 into the luminometer 950,
the MTU 160 is placed by the right-side transport mechanism 500
into an available MTU ramp-down station, or chiller, to decrease
the temperature of the MTU 160 to 24.+-.3.degree. C. It has been
determined that the MTU contents exhibit a more consistent
chemiluminescent "light-off" at this cooler temperature.
Luminometer
[0352] Referring to FIGS. 40-42C, a first embodiment of the
luminometer 950 includes an electronics unit (not shown) within a
housing 954. A photomultiplier tube (PMT) 956 linked to the
electronics unit extends from within the housing 954 through a PMT
plate 955, with the front end of the PMT 956 aligned with an
aperture 953. A preferred PMT is available from Hamamatsu Corp. of
Bridgewater, N.J. as model number HC 135. Signal measurements using
the preferred PMT are based on the well known photon counter
system.
[0353] The aperture 953 is centered in an aperture box 958 in front
of the PMT plate 955. The aperture 953 and aperture box 958 are
entirely enclosed by a housing, defined by a floor plate 964, a top
plate 966, the PMT plate 955, and a back frame 965 and back plate
967, which prevents stray light from entering the aperture 953 and
which is attached to the datum plate 82. An MTU transport path
extends through the housing in front of the aperture 953, generally
transversely to an optical axis of the aperture. MTUs 160 pass
through the luminometer 950 via the MTU transport path. A back rail
991 and a front rail 995 are disposed on opposite sides of the MTU
transport path and provide parallel horizontal flanges which
support the connecting rib structure 164 of an MTU 160 disposed
within the luminometer 950. Revolving doors 960 are supported for
rotation within associated door housings 961 disposed on opposite
ends of the MTU transport path and are turned by door motors 962,
which may comprise stepper motors or DC gear motors.
[0354] The door housings 961 provide openings through which MTUs
160 can enter and exit the luminometer 950. An MTU 160 enters the
luminometer 950 by means of the right-side transport mechanism 500
inserting the MTU 160 through one of the door housings 961. The MTU
160 exits the luminometer under the influence of an MTU transport
assembly, various embodiments of which are described below, which
moves MTUs through the MTU transport path and eventually out of the
luminometer through the other door housing 961.
[0355] Revolving doors 960 are generally cylindrical and include a
cut-out portion 963. Each revolving door 960 can be rotated between
an open position, in which the cut-out portion 963 is generally
aligned with the opening of the associated door housing 961, so
that an MTU 160 can pass through the opening, and a closed
position, in which a side of the revolving door opposite the
cut-out portion 963 extends across the opening of the associated
door housing 961 so that neither an MTU 160 nor light can pass
through the opening. Except when an MTU 160 is entering or exiting
the luminometer 950, the revolving doors 960 are preferably in
their respective closed positions to prevent stray light from
entering the luminometer. Because test results are ascertained by
the amount of light detected by the PMT 956, stray light from
sources other than the receptacle 160 being sampled can cause
erroneous results.
[0356] As shown in FIGS. 40-42C, the MTU transport assembly may
include an MTU advance motor 972 which drives a lead screw 974
through a timing belt (not shown) or bevel gears (not shown). A
screw follower 976 engaged to the lead screw 974 is coupled to an
MTU bracket 977 extending away from lead screw 974 to engage the
MTU 160. The MTU bracket 977 has a guide flange 978 with an
elongated, slightly arcuate guide hole 979 formed therein. A guide
rod 980 extends through the luminometer 950 adjacent and parallel
to the lead screw 974. Guide rod 980 extends through guide hole
979.
[0357] To advance the MTU bracket 977 (from bottom to top in FIG.
42C), the lead screw 974 turns counter-clockwise, as viewed in FIG.
42B. Due to system friction, the screw follower 976 and the MTU
bracket 977 will also turn counter-clockwise with the lead screw
974 until the guide rod 980 contacts the left-side of the guide
hole 979. When guide rod 980 contacts the side of guide hole 979,
MTU bracket 977 and screw follower 976 can no longer rotate with
lead screw 974, and further rotation of the lead screw 974 will
cause the MTU bracket 977 and screw follower 976 to advance along
the lead screw 974. Arms 981 extending from the MTU bracket 977
will also rotate counter-clockwise over a limited arc to engage the
MTU 160 and advance it through the luminometer 950, as the lead
screw 974 rotates.
[0358] After the MTU 160 has passed the PMT 956, that MTU is
ejected from the luminometer 950 and the next MTU can be pulled
through the luminometer 950. The MTU bracket 977 moves toward the
MTU entrance end of the MTU transport path by clockwise rotation of
the lead screw 974. System friction will cause the screw follower
976 and MTU bracket 977 to rotate clockwise until the guide rod 980
contacts the right-side of guide opening 979, after which,
continued rotation of the lead screw 974 will cause the screw
follower 976 and the MTU bracket 977 to retreat along the lead
screw 974. This clockwise movement of the MTU bracket 977 will
cause the arms 981 to rotate clockwise over a limited arc to
disengage from the MTU, so the MTU bracket 977 can retreat without
contacting the MTU. That is, the arms 981 will pass over the top of
the MTU as the MTU bracket 977 retreats
[0359] As shown in FIG. 41, a blinder 982, driven by a blinder
actuator 993, moves vertically up and down, in alignment with the
aperture 953. Blinder 982 includes a front panel 983 which is
mounted for sliding movement with respect to the aperture box 958
and which includes a generally rectangular opening (not shown)
formed therein which can be aligned with the aperture 953. A top
portion of the front panel 983 blocks the aperture 953 when the
opening formed in panel 983 is not aligned with the aperture 953
and thus operates as a shutter for the aperture 953. The blinder
982 includes two side-walls 987, arranged in parallel on opposite
sides of the opening and generally perpendicular to the front panel
983, and a back wall 988 spanning the back edges of the sidewalls
987 opposite the front wall 983 and generally parallel to the front
wall 983. The side-walls 987 and the back wall 988 define a partial
rectangular enclosure sized to accommodate one receptacle vessel
162 of the MTU 160 when the blinder 982 is moved up beneath one of
the receptacle vessels 162 of an MTU 160 by the blinder actuator
993. Blinder actuator 993 may be a linear stepper actuator
including a stepper motor 992 and a lead screw 994. HSI linear
stepper actuators, available from Haydon Switch and Instrument,
Inc. of Waterbury, Conn. have been used.
[0360] After the MTU 160 is placed into the luminometer 950 by the
right-side transport mechanism 500, the motor 972 is energized to
pull the first receptacle vessel of the MTU into alignment with the
aperture 953. The blinder 982, which is normally stowed out of the
MTU transport path, is raised by the blinder actuator 993 until the
side walls 987 and back wall 988 of the blinder 982 surround the
receptacle vessel 162 and the opening formed in the front panel 983
of the blinder 982 is aligned with the aperture 953. The blinder
982 substantially prevents light from sources other than the
receptacle vessel 162 in front of the aperture 953 from reaching
the aperture 953, so that the PMT 956 detects only light emissions
from the receptacle vessel directly in front of the aperture
953.
[0361] With the PMT shutter open, different detecting reagents
(Detect I and Detect II), drawn from containers 1146, 1170 of the
lower chassis 1100, are sequentially delivered into the aligned
receptacle vessel 162 through dedicated delivery lines (not shown)
extending to a reagent port 984 at the top of the luminometer 950.
The Detect I and Detect II reagents are hydrogen
peroxide-containing and sodium hydroxide-containing reagents,
respectively, and combine to form a basic hydrogen peroxide
solution which enhances the chemiluminescence of acridinium ester
label which has not been hydrolyzed. Because basic hydrogen
peroxide is unstable, the Detect I and Detect II reagents are
preferably combined in the receptacle tube 162 just prior to
detection in the luminometer 950.
[0362] After the addition of Detect II, the light emitted from the
contents of the receptacle vessel 162 is detected using the PMT 956
and the PMT shutter is then closed. The PMT 956 converts light
emitted by chemiluminescent labels into electrical signals
processed by the electronics unit and thereafter sent to the
controller 1000 or other peripheral unit via cables (not shown)
linked to a connector 986.
[0363] In cases where less sensitivity is required, it may be
possible to use an optical sensor in place of a photomultiplier
tube. A diode is an example of an acceptable optical sensor which
can be used with the luminometer 950. An optical sensor may also be
appropriate when the material of the MTU 160 is relatively
transparent, rather than the translucent appearance of the
preferred polypropylene material. When selecting a material for the
MTU 160, care should be taken to avoid materials that naturally
luminesce or are predisposed to electrostatic build-up, either of
which can increase the chances of a false positive or interfering
with quantification measurements.
[0364] The above-described process is repeated for each receptacle
vessel 162 of the MTU 160. After the chemiluminescent signal from
each receptacle vessel 162 of the MTU 160 has been measured, the
motor 972 advances to move the MTU 160 through the exit door 961
and out of the luminometer 950 and into the amplicon deactivation
station 750.
[0365] An alternate, and presently preferred, luminometer is
generally designated by reference number 1360 in FIG. 43.
Luminometer 1360 includes a housing 1372 having a bottom wall 1370,
door assemblies 1200 on opposite sides of the bottom wall 1370
which define end portions of the housing 1372, an optical sensor
shutter assembly 1250 which defines a front wall of the housing
1370, a top wall (not shown), and a back wall (not shown), which
complete the housing 1370 and define an enclosure therein. The
right-side door assembly 1200 defines a receptacle entrance opening
1374, and the left-side door assembly 1200 defines a receptacle
exit opening 1376 through which a MTU 160 can be passed into and
out of the housing 1370. Each door assembly 1200 controls access
through the respective opening 1374 or 1376 and comprises an end
wall 1202, a cover plate 1232, and a rotating door 1220 rotatably
disposed between the end wall 1202 and the cover plate 1232. The
optical sensor aperture shutter assembly 1250 controls light
entering an optical sensor (not shown in FIG. 43), for example a
photomultiplier tube. Luminometer 1360 includes a light receiver
mounting wall 1250 and a cover plate 1290 having an aperture 1292
formed therein.
[0366] A bar code scanner 1368 is attached to a front portion of
the housing 1372 for scanning MTUs prior to their entry to the
luminometer 1360.
[0367] A receptacle transport assembly 1332 moves a receptacle
(e.g., a MTU 160) through the luminometer 1360 from the entrance
opening 1374 to the exit opening 1376. The assembly 1332 includes a
transport 1342 movably carried on a threaded lead screw 1340 that
is rotated by a motor 1336 coupled to the lead screw 1340 by a belt
(not shown).
[0368] A dispensing nozzle 1362 is attached in the top wall (not
shown) and is connected by conduit tubes 1364 and 1366 to a pump
and ultimately to bottles 1146 and 1170 in the lower chassis 1100.
Nozzle 1362 dispenses the "Detect I" and the "Detect II" reagents
into the receptacles 162 of the MTU 160 within the housing
1372.
[0369] A receptacle vessel positioner assembly 1300 is disposed
within the housing 1372 and is constructed and arranged to position
each tube 162 of the MTU 160 in front of the aperture 1292 and to
optically isolate each tube being positioned from adjacent tubes,
so that only light from one tube at a time enters the aperture
1292. The positioner assembly 1300 comprises a receptacle
positioner 1304 rotatably mounted within a positioner frame 1302
that is secured to the floor 1370 of the housing 1372.
[0370] The door assembly 1200 for the MTU entrance opening 1374 and
exit opening 1376 of the luminometer 1360 is shown in FIG. 44. Door
assembly 1200 includes a luminometer end-wall 1202 which forms an
end wall of the luminometer housing 1372. End-wall 1202 includes a
first recessed area 1206 with a second, circular recessed area 1208
superimposed on the first recessed area 1206. A circular groove
1207 extends about the periphery of the circular recessed area
1208. A slot 1204, having a shape generally conforming to a
longitudinal profile of an MTU 160, is formed in the circular
recessed area 1208 to one side of the center thereof. A short
center post 1209 extends from the center of the circular recessed
area 1208.
[0371] The rotating door 1220 is circular in shape and includes an
axial wall 1222 extending about the periphery of the rotating door
1220. The axial wall 1222 is disposed a short radial distance from
the outer peripheral edge of the rotating door 1220, thus defining
an annular shoulder 1230 about the outermost peripheral edge
outside the axial wall 1222. A slot 1226, having a shape generally
conforming to the longitudinal profile of an MTU is formed in the
rotating door 1220 at an off-center position.
[0372] The rotating door 1220 is installed into the circular
recessed area 1208 of the end-wall 1202. A central aperture 1224
receives the center post 1209 of the end-wall 1202, and circular
groove 1207 receives axial wall 1222. The annular shoulder 1230
rests on the flat surface of the recessed area 1206 surrounding the
circular recessed area 1208.
[0373] End-wall 1202 includes a drive gear recess 1210 which
receives therein a drive gear 1212 attached to the drive shaft of a
motor 1213 (See FIG. 43 in which only the motor 1213 for the right
side door assembly 1200 is shown). Motor 1213 is preferably a DC
gear motor. A preferred DC gear motor is available from Micro Mo
Electronics, Inc. of Clearwater, Fla., under model number
1524T024SR 16/7 66:1. The outer circumference of the axial wall
1222 of the rotating door 1220 has gear teeth formed thereon which
mesh with the drive gear 1212 when the shutter is installed into
the circular recess 1208.
[0374] The cover plate 1232 is generally rectangular in shape and
includes a raised area 1234 having a size and shape generally
conforming to the recessed area 1206 of the end-wall 1202. Cover
plate 1232 has formed therein an opening 1236 having a shape
generally conforming to the longitudinal profile of an MTU, and,
when the cover plate 1232 is installed onto the end-wall 1202, the
raised rectangular area 1234 is received within the rectangular
recessed area 1206 and opening 1236 is in general alignment with
opening 1204. Thus, the rotating door 1220 is sandwiched between
the cover plate 1232 and the end-wall 1202, and the openings 1236
and 1204 together define the entrance opening 1374 and exit opening
1376.
[0375] When the drive gear 1212 is rotated by the motor 1213, the
rotating door 1220, enmeshed with the drive gear 1212, is caused to
rotate about the center post 1209. When the opening 1226 is aligned
with openings 1204 and 1236, MTUs 160 can be passed through the
opening 1374 (1376) of the door assembly 1200. With the rotating
door 1220 disposed within the circular recessed area 1208 and the
raised area 1234 of the cover plate 1232 disposed within the
recessed area 1206 of the end-wall 1202, a substantially
light-tight structure is achieved, whereby little or no light
enters through the door, when the opening 1226 is not aligned with
openings 1204 and 1236.
[0376] Optical slotted sensors are disposed within slots 1214 and
1216 disposed on the outer edge of the circular recessed area 1208
at diametrically opposed positions. Preferred sensors are available
from Optek Technology, Inc. of Carrollton, Tex., model number OPB
857. The slotted sensors disposed within slots 1214 and 1216 detect
the presence of a notch 1228 formed in the axial wall 1222 to
signal door open and door closed status.
[0377] The optical sensor aperture shutter assembly 1250 is shown
in FIG. 45. A light receiver, such as a photomultiplier tube 956,
is coupled with a light receiver opening 1254 formed in a light
receiver mounting wall 1252. The light receiver mounting wall 1252
includes a generally rectangular, two-tiered raised area 1256,
which defines a generally rectangular shoulder 1257 and a circular
recessed area 1258 superimposed on the rectangular raised area
1256. A circular groove 1261 extends about the periphery of
circular recessed area 1258. A center post 1259 is positioned at
the center of the circular recessed area 1258. Light receiver
opening 1254 is formed in the circular recessed area 1258. In the
illustrated embodiment, the light receiver opening 1254 is disposed
below the center post 1259, but the light receiver opening 1254
could be placed at any position within the circular recessed area
1258.
[0378] The aperture shutter assembly 1250 includes a rotating
shutter 1270 having an axial wall 1274 with gear teeth formed on
the outer periphery thereof. Axial wall 1274 is formed near, but
not at, the outer periphery of the shutter 1270, thereby defining
annular shoulder 1276. Rotating shutter 1270 is installed in the
circular recessed area 1258 with center post 1259 received within a
central aperture 1272 formed in the rotating shutter 1270 and with
axial wall 1274 received within circular groove 1261. A drive gear
1262 disposed within a gear recess 1260 and coupled to a drive
motor 1263 meshes with the outer gear teeth formed on the axial
wall 1274 of the rotating shutter 1270 to rotate the rotating
shutter 1270 about the center post 1259. A preferred drive motor
1263 is a DC gear motor available from Micro Mo Electronics, Inc.
of Clearwater, Fla., as model number 1524T024SR 16/7 66:1. Micro Mo
gear motors are preferred because they provide a high quality, low
backlash motor. An opening 1280 is formed in the rotating shutter
1270 which can be moved into and out of alignment with light
receiver opening 1254 as the rotating shutter 1270 is rotated.
[0379] With the shutter 1270 installed in the circular recessed
area 1258, a cover plate, or sensor aperture wall, 1290 is
installed onto the sensor mount 1252. As shown in FIG. 45A, sensor
aperture wall 1290 includes a generally rectangular, two-tiered
recessed area 1296 which defines a generally rectangular shoulder
1297 and which is sized and shaped to receive therein the
rectangular raised area 1256 of the sensor mount 1252. A sensor
aperture 1292 is formed through the aperture wall 1290 and is
generally aligned with the light receiver opening 1254 formed in
the sensor mount 1252. The sensor aperture 1292 is generally in the
shape of an elongated oval having a width generally corresponding
to the width of an individual receptacle vessel 162 of an MTU 160
and a height corresponding to the height of the intended viewing
area. Although opening 1280 of shutter 1270 is shown in the
illustrated embodiment to be circular, opening 1280 can have other
shapes, such as rectangular, with a width corresponding to the
width of a receptacle vessel 162 or an elongated oval similar to
sensor aperture 1292. Rotation of the rotating shutter 1270 to a
position in which the opening 1280 is aligned with the light
receiver opening 1254 and the sensor aperture 1292 permits light to
reach the PMT 956, and rotation of the rotating shutter 1270 to a
position in which the opening 1280 is not aligned with light
receiver opening 1254 and sensor aperture 1292 prevents light from
reaching the PMT 956.
[0380] Slotted optical sensors are disposed in slots 1264 and 1266
and detect a notch 1278 formed in the axial wall 1274 of the
shutter 1270 to detect opened and closed positions of the shutter
1270. Preferred slotted optical sensors are available from Optek
Technology, Inc., of Carrollton, Tex., as model number OPB857.
[0381] The aperture wall 1290 includes an upwardly facing shoulder
1294 extending across the width thereof. A downwardly facing
shoulder of the MTU 160, defined by the connecting rib structure
164 of the MTU 160 (see FIG. 58), is supported by the shoulder 1294
as the MTU 160 slides through the luminometer.
[0382] The receptacle vessel positioner assembly 1300 is shown in
FIGS. 46 and 48-49. The receptacle vessel positioner 1304 is
operatively disposed within the receptacle vessel positioner frame
1302. The receptacle vessel positioner 1304 is mounted in the
receptacle vessel positioner frame 1302 for rotation about a shaft
1308. Shaft 1308 is operatively coupled to a rotary solenoid, or,
more preferably, a gear motor 1306, to selectively rotate the
receptacle vessel positioner 1304 between the retracted position
shown in FIG. 46 and the fully extended position shown in FIG. 48.
A preferred gear motor drive is available from Micro Mo
Electronics, Inc. of Clearwater, Fla., as model number
1724T0245+16/7 134:1+X0520.
[0383] As shown in FIG. 47, the receptacle vessel positioner 1304
includes a V-block structure 1310 defining two parallel walls 1312.
Receptacle vessel positioner 1304 further includes an area at the
lower end thereof where a portion of the thickness of the
receptacle vessel positioner 1304 is removed, thus defining a
relatively thin arcuate flange 1314.
[0384] When an MTU 160 is inserted into the luminometer 1360, the
receptacle vessel positioner 1304 is in the retracted position
shown in FIG. 46. When an individual receptacle vessel 162 is
disposed in front of the sensor aperture 1292 (see FIG. 45A), so
that a sensor reading of the chemiluminescence of the contents of
the receptacle vessel 162 can be taken, the receptacle vessel
positioner 1304 rotates forwardly to the engaged position shown in
FIG. 49. In the engaged position shown in FIG. 49, the V-block 1310
engages the receptacle vessel 162, thus holding the receptacle
vessel in the proper position in alignment with the light receiver
aperture 1292 of the luminometer. As shown in FIG. 45, aperture
wall 1290 includes a protrusion 1298 extending from the back of
wall 1290 into the MTU passage of the luminometer. The protrusion
1298 is aligned with the aperture 1292 so that when the receptacle
vessel positioner 1304 engages a receptacle vessel 162, the
receptacle vessel is pushed laterally and encounters protrusion
1298 as a hard stop, thus preventing the receptacle vessel
positioner 1304 from significantly tilting the receptacle vessel
162 within the MTU passage. The parallel sidewalls 1312 of the
V-block 1310 prevent stray light from adjacent receptacle vessels
162 of the MTU 160 from reaching the light receiver while a reading
is being taken of the receptacle vessel 162 disposed directly in
front of the aperture 1292.
[0385] A slotted optical sensor 1318 is mounted to a lower portion
of the frame 1302, with the arcuate flange 1314 operatively
positioned with respect to the sensor 1318. A preferred slotted
optical sensor is available from Optek Technology, Inc., of
Carrollton, Tex., as model number OPB930W51. An opening 1316 is
formed in the flange 1314. Opening 1316 is properly aligned with
the sensor 1318 when the receptacle vessel positioner 1304 engages
a receptacle vessel 162 and the receptacle vessel 162 and
protrusion 1298 prevent further rotation of the receptacle vessel
positioner 1304. If a receptacle vessel 162 is not properly
positioned in front of the receptacle vessel positioner 1304, the
receptacle vessel positioner 1304 will rotate forwardly to the
position shown at FIG. 48, in which case opening 1316 will not be
aligned with the sensor 1318 and an error signal will be
generated.
[0386] If a gear motor 1306 is employed for rotating the receptacle
vessel positioner 1304, it is necessary to provide a second sensor
(not shown) to generate a positioner-retracted, i.e., "home",
signal to shut off the gear motor when the receptacle vessel
positioner 1304 is fully retracted, as shown in FIG. 46. A
preferred sensor is available from Optek Technology, Inc. of
Carrollton, Tex. as model number OPB900W.
[0387] The MTU transport assembly 1332 is shown in FIG. 50. The MTU
transport assembly 1332 is operatively positioned adjacent a top
edge of an intermediate wall 1330 (not shown in FIG. 43) of the
luminometer 1360. Intermediate wall 1330, which defines one side of
the MTU transport path through the luminometer housing 1372,
includes a rectangular opening 1334. The receptacle vessel
positioner frame 1302 (see, e.g., FIG. 48) is mounted to the
intermediate wall 1330 proximate the opening 1334, and the
receptacle vessel positioner 1304 rotates into engagement with an
MTU 160 through the opening 1334.
[0388] The MTU transport 1342 is carried on the threaded lead screw
1340 and includes a screw follower 1344 having threads which mesh
with the threads of the lead screw 1340 and an MTU yoke 1346 formed
integrally with the screw follower 1344. As shown in FIG. 51, the
MTU yoke 1346 includes a longitudinally-extending portion 1356 and
two laterally-extending arms 1348 and 1350, with a longitudinal
extension 1352 extending from the arm 1350. The lead screw 1340 is
driven, via a drive belt 1338, by the stepper motor 1336. A
preferred stepper motor is a VEXTA motor, available from Oriental
Motors Ltd. of Tokyo, Japan, model PK266-01A, and a preferred drive
belt is available from SDP/SI of New Hyde Park, N.Y.
[0389] When an MTU 160 is inserted into the MTU transport path of
the luminometer 950 by the right-side transport mechanism 500, the
first receptacle vessel 162 of the MTU 160 is preferably disposed
directly in front of the sensor aperture 1292 and is thus properly
positioned for the first reading. The width of the yoke 1346
between the lateral arms 1348 and 1350 corresponds to the length of
a single MTU 160. The transport 1342 is moved between a first
position shown in phantom in FIG. 50 and a second position by
rotation of the lead screw 1340. Slotted optical sensors 1341 and
1343 respectively indicate that the transport 1342 is in the either
the first or second position. Due to friction between the lead
screw 1340 and the screw follower 1344, the MTU transport 1342 will
have a tendency to rotate with the lead screw 1340. Rotation of the
MTU transport 1342 with the lead screw 1340 is preferably limited,
however, to 12 degrees by engagement of a lower portion of the yoke
1346 with the top of the intermediate wall 1330 and engagement of
an upper stop 1354 with the top cover (not shown) of the
luminometer housing 1372.
[0390] To engage the MTU that has been inserted into the
luminometer 1360, the lead screw 1340 rotates in a first direction,
and friction within the threads of the screw follower 1344 and the
lead screw 1340 causes the transport 1342 to rotate with lead screw
1340 upwardly until the upper stop 1354 encounters the top cover
(not shown) of the luminometer 1360. At that point, continued
rotation of the lead screw 1340 causes the transport 1342 to move
backward to the position shown in phantom in FIG. 50. The lateral
arms 1348, 1350 pass over the top of the MTU as the transport 1342
moves backward. Reverse rotation of the lead screw 1340 first
causes the transport 1342 to rotate downwardly with the lead screw
1340 until a bottom portion of the yoke 1346 encounters the top
edge of the wall 1330, at which point the lateral arms 1348 and
1350 of the yoke 1346 straddle the MTU 160 disposed within the
luminometer 1360.
[0391] The MTU transport mechanism 1332 is then used to
incrementally move the MTU 160 forward to position each of the
individual receptacle vessels 162 of the MTU 160 in front of the
optical sensor aperture 1292. After the last receptacle vessel 162
has been measured by the light receiver within the luminometer, the
transport 1342 moves the MTU 160 to a position adjacent the exit
door, at which point the lead screw 1340 reverses direction, thus
retracting the transport 1342 back, as described above, to an
initial position, now behind the MTU 160. Rotation of the lead
screw 1340 is again reversed and the transport 1342 is then
advanced, as described above. The exit door assembly 1200 is opened
and the longitudinal extension 1352 of the yoke 1346 engages the
MTU manipulating structure 166 of the MTU 160 to push the MTU 160
out of the luminometer exit door and into the deactivation queue
750.
Deactivation Station
[0392] In the amplicon deactivation station 750, dedicated delivery
lines (not shown) add a deactivating solution, such as buffered
bleach, into the receptacle vessels 162 of the MTU 160 to
deactivate the remaining fluid in the MTU 160. The fluid contents
of the receptacle vessels are aspirated by tubular elements (not
shown) connected to dedicated aspiration lines and collected in a
dedicated liquid waste container in the lower chassis 1100. The
tubular elements preferably have a length of 4.7 inches and an
inside diameter of 0.041 inches.
[0393] An MTU shuttle (not shown) moves the MTUs 160 incrementally
(to the right in FIG. 3) with the delivery of each subsequent MTU
160 into the deactivation station 750 from the luminometer 950.
Before an MTU can be delivered to the deactivation queue 750 by the
luminometer 950, the MTU shuttle must be retracted to a home
position, as sensed by a strategically positioned optical slot
switch. After receiving an MTU 160 from the luminometer, the
shuttle moves the MTU 160 to a deactivation station where the
dedicated delivery lines connected to dedicated injectors dispense
the deactivating solution into each receptacle vessel 162 of the
MTU 160. Previous MTUs in the deactivation queue, if any, will be
pushed forward by the distance moved by the MTU shuttle. Sensors at
the deactivation station verify the presence of both the MTU and
the MTU shuttle, thus preventing the occurrence of a deactivating
fluid injection into a non-existent MTU or double injection into
the same MTU.
[0394] An aspiration station (not shown) includes five,
mechanically coupled aspirator tubes mounted for vertical movement
on an aspirator tube rack and coupled to an actuator for raising
and lowering the aspirator tubes. The aspiration station is at the
last position along the deactivation queue before the MTUs are
dropped through a hole in the datum plate 82 and into the waste bin
1108. Each time an MTU moves into the deactivation station, the
aspirator tubes cycle up and down one time, whether an MTU is
present in the aspiration station or not. If an MTU is present, the
aspirator tubes aspirate the fluid contents from the MTU. When the
next MTU is moved into the deactivation station by the MTU shuttle,
the last-aspirated MTU is pushed off the end of the deactivation
queue and falls into the waste bin 1108.
[0395] The steps and sequence of the above-described assay
procedure performed on the analyzer 50 in the preferred mode of
operation are graphically and succinctly described in the document
Gen-Probe TIGRIS Storyboard v.1.0, Jun. 23, 1997, a copy of which
was filed with the provisional disclosure upon which priority is
claimed for the present specification and the contents of which are
hereby incorporated by reference.
[0396] Ideally, the analyzer 50 can run about 500 preferred assays
in an 8 hour period, or about 1,000 preferred assays in a 12 hour
period. Once the analyzer 50 is set-up and initialized, it
ordinarily requires little or no operator assistance or
intervention. Each sample is handled identically for a given assay,
although the analyzer is capable of simultaneously performing
multiple assay types in which different MTUs may or may not be
handled identically. Consequently, manual pipetting, incubation
timing, temperature control, and other limitations associated with
manually performing multiple assays are avoided, thereby increasing
reliability, efficiency, and throughput. And because an operator's
exposure to samples is generally limited to the loading of samples,
risks of possible infection are greatly reduced.
[0397] While the invention has been described in connection with
what are presently considered to be the most practical and
preferred embodiments, it is to be understood that the invention is
not to be limited to the disclosed embodiments, but, on the
contrary, is intended to cover various modifications and equivalent
arrangements included within the spirit and scope of the appended
claims.
[0398] Furthermore, those of the appended claims which do not
include language in the "means for performing a specified function"
format permitted under 35 U.S.C. .sctn.112( 16), are not intended
to be interpreted under 35 U.S.C. .sctn.112( 16) as being limited
to the structure, material, or acts described in the present
specification and their equivalents.
* * * * *