U.S. patent application number 16/284855 was filed with the patent office on 2020-02-20 for point-of-care diagnostic cartridge having a digital micro-fluidic testing substrate.
The applicant listed for this patent is Paratus Diagnostics, LLC. Invention is credited to John Carrano, John Jacob Carrano, Roland Schneider.
Application Number | 20200057059 16/284855 |
Document ID | / |
Family ID | 59359399 |
Filed Date | 2020-02-20 |
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United States Patent
Application |
20200057059 |
Kind Code |
A1 |
Carrano; John Jacob ; et
al. |
February 20, 2020 |
POINT-OF-CARE DIAGNOSTIC CARTRIDGE HAVING A DIGITAL MICRO-FLUIDIC
TESTING SUBSTRATE
Abstract
A specimen delivery cartridge includes a lower housing, and an
upper housing. The upper housing is coupled to the lower housing at
a hinge. The specimen delivery cartridge further comprises a
testing chamber comprising a paper testing substrate. The paper
testing substrate may include a wicking conduit and a plurality of
test areas. The specimen delivery cartridge may also include a lens
assembly proximate the plurality of test areas and operable to
transmit light emissions from the plurality of test areas to an
image sensor of a computing device. In some embodiments, the
specimen delivery cartridge includes a testing substrate having a
plurality of test areas made of an array of electrodes. Each
electrode is printed on a first side of the testing substrate and
coupled to a conductive via formed in the testing substrate and a
conductive trace printed on a second, opposing side of the testing
substrate.
Inventors: |
Carrano; John Jacob; (San
Marcos, TX) ; Carrano; John; (San Marcos, TX)
; Schneider; Roland; (San Marcos, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Paratus Diagnostics, LLC |
San Marcos |
TX |
US |
|
|
Family ID: |
59359399 |
Appl. No.: |
16/284855 |
Filed: |
February 25, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15418526 |
Jan 27, 2017 |
10436781 |
|
|
16284855 |
|
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|
|
62287781 |
Jan 27, 2016 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01L 2200/16 20130101;
B01L 2400/0427 20130101; G01N 33/558 20130101; B01L 2300/161
20130101; G01N 33/54373 20130101; B01L 2200/0668 20130101; B01L
2300/0864 20130101; B01L 2300/126 20130101; B01L 2400/043 20130101;
B01L 2400/0605 20130101; B01L 3/502 20130101; B01L 2300/0654
20130101; B01L 2200/10 20130101 |
International
Class: |
G01N 33/543 20060101
G01N033/543; G01N 33/558 20060101 G01N033/558; B01L 3/00 20060101
B01L003/00 |
Claims
1. A specimen delivery cartridge having a testing substrate
comprising a plurality of test areas, the plurality of test areas
comprising an array of electrodes, wherein: each electrode is
printed on a first side of the testing substrate, each electrode is
coupled to a conductive via formed in the testing substrate; and
each conductive via is coupled to one of a plurality of conductive
traces printed on a second, opposing side of the testing
substrate.
2. The specimen delivery cartridge of claim 1, wherein the testing
substrate comprises a paper substrate.
3. The specimen delivery cartridge of claim 1, wherein the testing
substrate comprises a flexible paper substrate that is operable to
receive a digital microfluidic circuit.
4. The specimen delivery cartridge of claim 1, wherein each column
of electrodes overlies each of the conductive traces coupled to the
electrodes in the column.
5. The specimen delivery cartridge of claim 1, further comprising
an electronic connector, wherein the electronic connector comprises
a rigid material and a portion of the testing substrate wrapped
around an extension of the rigid material.
6. The specimen delivery cartridge of claim 5, wherein each of the
conductive traces extends around the extension of the rigid
material to form a pin of the electronic connector.
7. The specimen delivery cartridge of claim 6, wherein the
electronic connector comprises a connector selected from the group
consisting of a USB connector, a micro-USB connector, and a
mini-USB connector.
8. A method for manufacturing a specimen delivery cartridge testing
substrate for use in a specimen delivery cartridge, the method
comprising: printing a plurality of electrodes on a first side of
the testing substrate with a conductive ink; filling a plurality of
holes in the testing substrate adjacent each electrode with the
conductive ink to form a via through the substrate to each of the
plurality of electrodes; and printing a plurality of conductive
traces on a second, opposing side of the testing substrate, where
each of the conductive traces is electrically coupled to a via.
9. The method of claim 8, wherein printing a plurality of
electrodes comprises printing an array of electrodes.
10. The method of claim 9, wherein each column in the array of
electrodes overlies each of the conductive traces coupled to the
electrodes in the column.
11. The method of claim 8, further comprising forming an electronic
connector, by wrapping the testing substrate about a connector
extension, the connector extension comprising a rigid connector
substrate.
12. The method of claim 11, wherein each of the conductive traces
extends around the extension of the rigid connector substrate to
form a pin of the electronic connector.
13. The method of claim 12, wherein the electronic connector
comprises a connector selected from the group consisting of a USB
connector, a micro-USB connector, and a mini-USB connector.
14. A method of analyzing a test specimen using a specimen delivery
cartridge, the method comprising: interacting a plurality of
magnetic particles with a test specimen in a specimen delivery
chamber to form magnetic test particles; immobilizing the magnetic
test particles; removing a supernatant fluid while maintaining the
magnetic test particles in an immobilized state; releasing the
magnetic test particles from the immobilized state; and adding a
fluid to the specimen delivery chamber to form a test solution
comprising the magnetic test particles.
15. The method of claim 14, wherein immobilizing the magnetic test
particles comprises applying a magnetic field across a chamber
comprising the test solution.
16. The method of claim 15, wherein applying a magnetic field
comprises activating an electromagnet.
17. The method of claim 16, further comprising moving the test
solution from the specimen delivery chamber to a testing substrate
comprising a plurality of test areas, the plurality of test areas
comprising an array of electrodes, wherein: each electrode is
printed on a first side of the testing substrate, each electrode is
coupled to a conductive via formed in the testing substrate; and
each conductive via is coupled to one of a plurality of conductive
traces printed on a second, opposing side of the testing substrate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/418,526 filed on Jan. 27, 2017 entitled
POINT-OF-CARE DIAGNOSTIC CARTRIDGE HAVING A DIGITAL MICRO-FLUIDIC
TESTING SUBSTRATE, which claims the benefit of U.S. Provisional
Application No. 62/287,781 filed Jan. 27, 2016 both of which are
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to the field of
medical diagnostics and more particularly to in vitro medical
diagnostic devices including point-of-care in vitro medical
diagnostic devices.
BACKGROUND OF THE INVENTION
[0003] There is a recognized and compelling need for the rapid and
accurate diagnosis of common infectious diseases in an out-patient
setting. This need results from a rapidly emerging trend toward
what is sometimes referred to as "patient centric care" in which
convenience--along with better health outcomes and
low-cost--becomes a key market driver.
[0004] The field of in vitro diagnostics is well established, with
many manufacturers and a wide spectrum of products and
technologies. The testing for infectious pathogens in human patient
specimens is largely confined to centralized laboratory testing in
Clinical Laboratory Improvement Amendment (CLIA) rated
medium-complexity or high-complexity facilities. Commonplace
techniques used in such laboratories include traditional culturing
of specimens, immunological assaying using Enzyme-Linked
Immunosuppressant Assay (ELISA), nucleic acid testing (such as
polymerase chain reaction, PCR), and other methods.
SUMMARY
[0005] In accordance with an illustrative embodiment, a specimen
delivery cartridge includes a lower housing, and an upper housing.
The upper housing is coupled to the lower housing at a hinge. The
specimen delivery cartridge further comprises a testing chamber
comprising a paper testing substrate. The paper testing substrate
may include a wicking conduit and a plurality of test areas. The
specimen delivery cartridge may also include a lens assembly
proximate the plurality of test areas and operable to transmit
light emissions from the plurality of test areas to an image sensor
of a computing device.
[0006] In accordance with another embodiment, a specimen delivery
cartridge includes a testing substrate comprising a plurality of
test areas, the plurality of test areas comprising an array of
electrodes. Each electrode is printed on a first side of the
testing substrate; each electrode is coupled to a conductive via
formed in the testing substrate; and each conductive via is coupled
to one of a plurality of conductive traces printed on a second,
opposing side of the testing substrate.
[0007] In accordance with another illustrative embodiment, a method
for manufacturing a specimen delivery cartridge testing substrate
for use in a specimen delivery cartridge includes printing a
plurality of electrodes on a first side of the testing substrate
with a conductive ink. The method further includes filling a
plurality of holes in the testing substrate adjacent each electrode
with the conductive ink to form a via through the substrate to each
of the plurality of electrodes. In addition, the method includes
printing a plurality of conductive traces on a second, opposing
side of the testing substrate, where each of the conductive traces
is electrically coupled to a via.
[0008] In accordance with another illustrative embodiment, a method
of analyzing a test specimen using a specimen delivery cartridge
includes interacting a plurality of magnetic particles with a test
specimen in a specimen delivery chamber to form magnetic test
particles; immobilizing the magnetic test particles; removing a
supernatant fluid while maintaining the magnetic test particles in
an immobilized state; releasing the magnetic test particles from
the immobilized state; and adding a fluid to the specimen delivery
chamber to form a test solution comprising the magnetic test
particles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic, perspective view of a specimen
delivery cartridge and a computing device coupled to a mating
adapter;
[0010] FIG. 2 is a schematic, perspective view of a specimen
delivery cartridge in an open position;
[0011] FIG. 3 is a schematic, perspective view of the specimen
delivery cartridge of FIG. 2 in which certain components are hidden
to illustrate a testing substrate having an array of test
electrodes;
[0012] FIG. 4 is a schematic, perspective view of a plunger having
a plurality of actuation surfaces;
[0013] FIG. 5 is a schematic, perspective view of an alternative
embodiment of a specimen delivery cartridge, with certain portions
shown in hidden line;
[0014] FIG. 5A is a schematic, perspective view of the specimen
delivery cartridge of FIG. 5 in a closed position;
[0015] FIG. 6 is a perspective view of a detecting portion of the
specimen delivery cartridge of FIG. 5 in partial section view;
[0016] FIG. 7 is a perspective view of the specimen delivery
cartridge of FIG. 5 in partial section view;
[0017] FIGS. 8A and 8B show alternative, perspective views of an
illustrative embodiment of a substrate having a digital
microfluidic (DMF) circuit with integrated reagent storage
packs;
[0018] FIGS. 9A and 9B show a comparison of alternative embodiments
of a substrate having a digital microfluidic (DMF) circuit;
[0019] FIGS. 10A and 10B are perspective, and side-section views,
respectively, of a portion of a paper substrate having a cutout
formed therein to facilitate the printing of an interconnect;
[0020] FIGS. 11A and 11B are perspective, and side-section views,
respectively, of a portion of a paper substrate having a portion of
a microfluidic circuit formed thereon that includes a portion of an
interconnect;
[0021] FIGS. 12A and 12B are perspective, and side-section views,
respectively, of a portion of a paper substrate having a portion of
a microfluidic circuit formed thereon that includes an
electrode;
[0022] FIGS. 13A-13D show schematic representations of a process
for analyzing a specimen using a digital microfluidic (DMF)
circuit;
[0023] FIG. 14 is a flow chart illustrating a process corresponding
to the steps illustrated in FIGS. 13A-13D;
[0024] FIG. 15 is a partial, section view of a portion of a
specimen delivery cartridge that includes a ground pane
electrode;
[0025] FIGS. 16A and 16B are partial, section view of a portion of
a specimen delivery cartridge that includes a mechanism for
delivering reagents displaced from a specimen collection chamber
onto a DMF electrode;
[0026] FIG. 17 is a partial, section view of a portion of a
specimen delivery cartridge in which a testing substrate is formed
to include a hybrid DMF circuit using a combination of drive
electrodes with a hydrophilic pad.
[0027] FIG. 18 illustrates a schematic, section view of a two-stage
specimen delivery cartridge;
[0028] FIG. 19 is an alternative section view of the two-stage
specimen delivery cartridge of FIG. 18; and
[0029] FIGS. 20 and 21 are schematic, perspective views of
alternative embodiments of circuitous wicking paths.
DETAILED DESCRIPTION
[0030] The conventional model for infectious disease diagnosis
relies heavily on centralized laboratory testing (e.g. culture),
which can often take two to four days to provide a reliable result.
Applicant performed time-and-motion studies of medical practice and
patient flow in the current model of infectious disease diagnosis
and compared it to the new model relying on the devices described
in this disclosure. A consequence of the conventional model is that
patients are not necessarily properly diagnosed on their first
visit; nor are they given the correct drug prescription. This
results in money wasted on either incorrect or unnecessary
prescriptions, inconvenience to patients owing to repeat visits,
and even the potential for otherwise treatable illnesses to
progress to more serious conditions requiring expensive hospital
stays. In addition, it is noted that the over-prescription of
antibiotics is not only a cost burden to the healthcare system, but
perhaps more importantly may contribute to the increasing frequency
of antibiotic resistant strains in the community, which is a
national health concern.
[0031] There are some rapid diagnostic tests (RDTs) on the market
today that are suitable for use in an out-patient setting. These
RDTs, however, are simple "rule-in/rule-out" tests which do not
necessarily inform clinical decision-making. Furthermore, many of
these RDT's suffer from poor sensitivity and specificity, making
the validity and clinical utility of their results dubious at
best.
[0032] In diagnosing a patient, it is common for a physician to ask
is whether an illness is the consequence of a bacterial or a viral
pathogen. The present disclosure relates to a system that is able
to provide that answer during the patient visit and with
gold-standard accuracy. In this way, the correct diagnosis is
obtained, and the best treatment option prescribed.
[0033] In point-of-care diagnostics for infectious disease, a
premium is placed on the ability to achieve low-complexity and
low-cost while substantially improving health outcomes. Further, to
leverage the ubiquity of smartphones and other computing devices in
common use globally, a mating adaptor is disclosed that allows for
the use of a computing device, such as a smart phone, in connection
with a mating adaptor and specimen delivery cartridge, to carry out
a test for one or more pathogens. The mating adaptor accommodates
the form factor and interfaces of popular computing devices (e.g.,
smart phones) by providing for a variety of interfaces. Each
interface may equate to a customized adaptor that is operable to
mate with a particular smartphone. However, the adaptor interfaces
to the cartridge will generally be identical; meaning that the
cartridge will fit to any of a variety of a range of adaptors that
accommodate a corresponding range of smart phones or other
computing devices.
[0034] The specimen delivery cartridge may be considered to be
similar in some respects to the cartridge or "specimen delivery
apparatus" described in earlier-filed patent application Ser. No.
13/918,877 entitled "Specimen Delivery Apparatus" submitted by
applicant, which is hereby incorporated by reference.
[0035] Referring now to FIG. 1, in an illustrative embodiment, a
mating adaptor 100 is sized and configured to receive and pair with
a computing device 106 and a specimen delivery cartridge 110. The
mating adaptor 100 has a first receiving area that is sized and
configured to receive the computing device 106, which may be, for
example, a smart phone or dedicated handheld device. The mating
adaptor 100 also has a second receiving area that is sized and
configured to receive the specimen delivery cartridge 110. The
aforementioned pairing results in one or more of a physical
coupling, optical coupling, thermal coupling, communicative
coupling, or electrical coupling between the computing device 106
and the specimen delivery cartridge 110.
[0036] A representative specimen delivery cartridge 200 is
described in more detail below with regard to FIG. 2. Owing to the
enormous amount of research and development funds invested in the
development of smartphones and other computing devices, certain
capabilities exist with such computing devices that are relevant to
biological detection and clinical diagnostics. However, one
capability that an off-the-shelf smartphone lacks is the ability to
directly manipulate liquid fluids within its existing form factor,
or to accept bodily fluid specimens directly for analysis. The
specimen delivery cartridge 200 may be regarded as a consumable
cartridge that resolves the problems associated with acquiring a
wide variety of human, animal, agricultural, or environmental
specimens and introducing those safely into a point-of-care
diagnostic system for further assaying. This assaying may involve
some or all of the following steps: the introduction of additional
(liquid) biochemical reagents to a liquid specimen; the mixing and
agitation of said liquids; the heating of various but specific
liquids for distinct periods of time (known commonly as
incubation); the use of filters; and the use of various types of
particles, some of which might be magnetic in nature.
[0037] In an embodiment, the specimen delivery cartridge 200 is a
sealed device that may receive and process a liquid specimen
without exposing the computing device 106 or mating adapter 100
(described with regard to FIG. 1) to the fluid specimen. In such an
embodiment, all fluids, reagents, specimens and any other liquid
materials are safely contained internal to the specimen delivery
cartridge 200, and there is no fluid flow between any of the three
foregoing components because all flow occurs within the specimen
delivery cartridge 200.
[0038] The mating adapter 100 shown is illustrative only and it is
noted that different versions of mating adapter may be fabricated
to accommodate different types of computing devices on the market.
In an embodiment, the computing device 106 is a smart phone, and it
is noted that the computing device 106 may be made in any number of
dimensional configurations, each corresponding to a separately
fabricated smart phone. Similarly, the mating adapter 100
accommodates any specimen delivery cartridge 110, regardless of the
type of specimen used or assay format. In this sense, the mating
adapter 100 serves as a universal link for coupling a specimen
delivery cartridge 110 to a computing device 106.
[0039] To link the computing device 106 to a specimen delivery
cartridge 100, a user or operator first slides the mating adapter
100 over the computing device 106. This is a simple action that
requires no special training. To prompt the user to take the
correct action in forming the link, a visual indicator, such as an
arrow pointing in the direction the computing device 106 should be
slid to engage the mating adapter 100, is included on a surface of
the mating adapter 100 that receives the computing device 106. A
written instruction may also be embossed on the mating adapter 100
to ensure complete clarity. Similar and/or complementary orienting
features may be included on the specimen delivery cartridge
200.
[0040] Referring now to FIGS. 2-3, an illustrative embodiment of a
specimen delivery cartridge 200 is shown. The specimen delivery
cartridge 200 includes actuation posts 207 that form a portion of a
plunger 209 (FIG. 3). The plunger 209 is operable to cause a
precise, metered delivery of previously stored reagents on to a
surface for subsequent assay processing steps. The plunger 209 is
positioned below a lower intermediate member 208, shown here as a
generally planar member. The lower intermediate member 208 may
include arcuate or otherwise nonplanar surfaces in other
embodiments. In some embodiments, a lower vessel cavity of a
specimen collection chamber 236 resides in the lower intermediate
member 208. The posts 207 protrude from a lower housing body 206
through the lower intermediate member 208 at actuator ports 202. In
addition to providing access for the posts 207, actuator ports 202
may also serve to provide mechanical stability and alignment of the
plunger to complimentary reagent storage packs or reservoirs below
the lower intermediate member 208.
[0041] A lower housing body 206 of the specimen delivery cartridge
200 supports and may partially enclose the lower intermediate
member 208. Similarly, an upper intermediate member 201, shown as a
second planar component, is supported and partially enclosed by an
upper housing body 213 of the specimen delivery cartridge 200. A
locking mechanism 205 (e.g., a spring-loaded latch, permanent or
ratcheting latch, or a magnet) secures the upper housing body 213
to the complimentary lower housing body 206 of the specimen
delivery cartridge 200. A swab holder 262 provides for the easy
alignment of a swab that may be used to deliver a specimen into the
specimen collection chamber 236 as well as to secure positioning of
the swab as a result of the snapping of the swab shaft into holder
262. A cutter 264, which may be a build-in cutter formed integrally
to the upper housing body 206, cuts the swab shaft off upon
depression of the cutter button.
[0042] As described in more detail below, the specimen delivery
cartridge may include a plunger that is operable to introduce
various reagents necessary for the execution of a particular assay
protocol once a swab is positioned within the specimen collection
chamber 236. In such an embodiment, certain reagents may be
pre-packaged as components contained in the specimen delivery
cartridge 200.
[0043] In order to maintain low-complexity operation, a user of the
specimen delivery cartridge 200 may not have to be directly
involved in measuring, pipetting, introducing, or using reagents
separate from the cartridge to perform the assaying steps. To that
end, the plunger mechanism may assist in operation of the specimen
delivery cartridge 200 by automatically dispensing pre-determined
and metered amounts of one or more reagents in to or on to a
follow-on device, channel, or substrate.
[0044] This automatic operation may be accomplished by the closing
of the upper housing body 213 toward the lower housing body 206,
which causes the plunger posts 207 to be pushed down a
pre-determined distance. With the lower housing body 206 removed
(for illustrative purposes), as shown in FIG. 4, one can observe
that the plunger 209, in some embodiments, has a one-piece
construction that includes the actuation posts 207. Here, it is
noted that the terms "upper" and "lower" are used in this
specification as exemplary terms relative to the items as they are
shown in the figures and are not intended to be limiting as to the
actual orientation of the devices. To that end, other relative or
sequential may be substituted without changing the scope of this
disclosure (e.g., first may be substituted for upper, and second
may be substituted for lower, or vice versa).
[0045] Referring again to FIG. 3, the plunger 209 is configured to
perform metered dispensing of reagents from fluid dispensers or
reservoirs, shown here as four reagent storage packs 318, 320, 322,
324. The plunger 209 can be designed and fabricated to dispense
from any suitable number of fluid dispensers (1, 2, 3, 4, . . . n)
depending on the assay being conducted and certain limiting factors
such as the overall size (volume) of the available within the
specimen delivery cartridge 200. The plunger 209 is operable to
depress the reagent packs 318, 320, 322, 324 to cause the fluid
dispensers to dispense reagent on to an adjacent substrate surface
(plastic, paper, polymer, PCB, glass, sapphire, composite, metal,
or other material) or into an adjoining fluid transfer channel. In
the illustrated embodiment, upon activation of the plunger 209,
reagents from four fluid dispensers are dispensed on to specific
"landing pads", shown here as metal electrodes 328, 330, 332, 334.
In other embodiments, the landing pads may be wicking paths or
channels formed from, for example, a wicking fiber or paper
substrate.
[0046] As shown in FIG. 3, the substrate 211 may include a paper
substrate with a digital microfluidic circuit 326 printed
thereupon. As referenced herein, microfluidics refers to the
precise control and manipulation of small volumes of fluids. As
such, a digital microfluidic circuit provides for discrete control
of fluid droplets that are manipulated on a substrate using
electrowetting (for example, using electrocapillary forces to move
droplets on a digital track, which may form a portion of a circuit,
from one electrode to the next). The substrate 211 may be formed of
plastic, glass, sapphire, PCB, or any other suitable material. In
another embodiment, however, the substrate is a wicking paper made
from nitrocellulose or another suitable material. The digital
microfluidic circuit includes of an array of electrodes 327
arranged to form a fluid flow path. In the embodiment of FIG. 3,
the electrodes 327 have been printed on paper using a conductive
ink. In an embodiment, the metal electrodes 328, 330, 332, 334 are
metal electrodes that are printed onto a paper substrate 211 using
a conductive ink.
[0047] Referring now to FIG. 4, an illustrative embodiment of the
plunger 209 is shown as having a plurality of actuation surfaces
210, 212, 214, 216. The plunger 209 is sized and configured to
engage a complimentary surface or surfaces of fluid dispensers
(e.g., reagent packs 318, 320, 322, 324) by virtue of the offset
actuation surfaces 210, 212, 214, 216. In some embodiments, the
actuation surfaces 210, 212, 214, 216 are planar. In other
embodiments, however, the actuation surfaces 210, 212, 214, 216 may
be slotted, curved, keyed, or of another suitable shape that is
selected to complement and engage the shape of the fluid dispensers
to be actuated by the actuation surfaces 210, 212, 214, 216. The
plunger 209 has posts 207 that are depressed upon the closing of
the specimen delivery cartridge 200.
[0048] In the illustrated embodiment, each of the plurality of
actuation surfaces 210, 212, 214, 216 are offset by a predetermined
distance to correspond to selected order, volume, or rate of
discharge (or a combination thereof) of fluid dispensers to be
actuated by the actuation surfaces 210, 212, 214, 216. Here, the
plunger 209 has a first actuation surface 210 of a particular
thickness corresponding to the volume of reagent intended to be
dispensed from the corresponding fluid dispenser. The plunger 204
may have a second actuator surface 212 of a particular thickness
(the same or different thickness than actuation surface 210). In
like manner, the plunger 204 may have a third actuator surface 214
of another particular thickness, and so on to an nth number of
actuator surfaces of particular thicknesses.
[0049] The plunger 209 may be fabricated from a single piece of
material, such as a molded plastic. In other embodiments, however,
different surfaces of the plunger 209 may be fabricated from
separate materials and later combined into one structure using
welds, adhesives, or other joining mechanisms.
[0050] FIG. 5 shows an embodiment of a specimen delivery cartridge
400 that is analogous to the specimen delivery cartridge 200
described above. The specimen delivery cartridge 400 includes a
first housing portion 402 and a second housing portion 404. The
first housing portion 402 includes a first vessel cavity 406 and
the second housing portion 404 includes a second vessel cavity 408.
When the first housing portion 402 and second, opposing subassembly
are closed together, the first vessel cavity 406 and second vessel
cavity 408 close to form opposing halves of a specimen collection
chamber 407 that accommodates a swab. The swab can be one of a
plurality of sizes, shapes, and material and is used to collect a
specimen (e.g., from a patient), for placement in the specimen
collection chamber 407. The specimen collection chamber 407
includes a roiling mechanism 410 that is operable to mix or
generate a vortexing or turbulent flow of liquids (such as an
elution reagent, lysis reagent, or other liquid) through the
specimen collection chamber 407 to interact with particles on the
swab and release such particles into the fluid to obtain a liquid
fluid specimen for subsequent processing.
[0051] The specimen collection chamber 407 is operable to deliver
fluid to a subsequent component of the specimen delivery cartridge
400 after the fluid has interacted with the specimen-containing
swab. To that end, the specimen collection chamber 407 includes a
fluid inlet 412, which may referred to as a fluid inlet orifice,
and a fluid outlet 414, which may be referred to as a fluid outlet
orifice. The fluid inlet 412 is operable to provide the fluid to
the specimen collection chamber 407 and the fluid outlet 414 is
operable to drain or otherwise remove the fluid from the specimen
collection chamber 407. Each of the fluid inlet 412 and fluid
outlet 414 may be an open flow path or may include a one way valve
to restrict and direct fluid flow into and out of the specimen
collection chamber 407. An elution button 421 is positioned on the
backside of the backside of the first housing portion 402 and is
operable to inject fluids fluid to the specimen collection chamber
407 and to induce roiling, stripping of specimen from swab, mixing,
and movement of fluid from the specimen collection chamber 407. In
an embodiment, the elution button 421 is an expandable and
compressible diaphragm that is operable to manipulate fluid within
the specimen collection chamber 407.
[0052] The specimen collection chamber 407 includes a swab entry
416 where the shaft of a swab crosses the boundary of the specimen
delivery cartridge 400 and is sealed by swab gasket 418 to prevent
leaking of fluids in the specimen collection chamber. In some
embodiments, the swab gasket 418 has a series of ridges 420 to
reduce in serial fashion the pressure drop between the inside of
the specimen collection chamber 407 and that of the ambient
environment surrounding the specimen delivery cartridge 400. Swab
gasket 418 abuts a complimentary chamber gasket 419 that forms a
complete seal of the swab inside the specimen delivery cartridge
400. In one embodiment, the swab gasket 418 and chamber gasket 419
are formed by a self-aligned molding process whereby a portion of
the structure of the specimen delivery cartridge forms the mold for
the gasket material (which can be rubber, synthetic polymer, or
other elastomeric material). In accordance with such a process, the
each of the swab gasket 418 and chamber gasket 419 may be
considered to be an over-molded part. The over-molding process may
be implemented using a mold cavity that is configured to receive a
portion of the cartridge to which the gasket is affixed, and to use
the received portion of the cartridge as a mold surface on which
the applicable gasket may then be molded. This type of
manufacturing process combines what would typically be an assembly
step with the fabrication process of molding, and thereby allows
for retention features to be built into the cartridge to better
retain the gasket than if the gasket were a purely assembled part.
For example, the portion of the surface of the second housing
portion 404 that receives the chamber gasket 419 may be scored or
etched prior to molding.
[0053] FIG. 5 shows a leaching chamber reservoir 426 of the
specimen delivery cartridge 400 that comprises a holding unit, such
as leaching chamber reservoir 426 into which certain reagents and
particles may be pre-loaded as part of a manufacturing step. In an
embodiment, the reagents and particles may be stored within a fluid
enclosed within a blister pack that is inserted into the leaching
chamber reservoir 426. The leaching chamber reservoir 426 is
operable to introduce certain reagents useful to the execution of
the given assay protocols. In some embodiments, the leaching
chamber reservoir 426 is actuated upon closure of the first housing
402 toward the second housing 404 such that a latch or linkage is
actuated upon closing to release a spring-loaded actuator, shown as
spring-loaded plunger 427 (shown in the alternative view of the
specimen delivery cartridge 400 of FIG. 5A) to actuate a piston 424
that pushes a gasket 422 through the leaching chamber reservoir 426
to propel fluid stored in the leaching chamber reservoir 426 toward
specimen collection chamber 407. The gasket 422 thereby seals the
specimen collection chamber 407 and provides a mechanism for
propelling ensconced reagents into the specimen collection chamber
407. The contents of the leaching chamber reservoir 426 are
delivered into the specimen collection chamber 407 through a
leaching chamber reagent inlet 425. The leaching chamber reservoir
426 or specimen collection chamber 407 can hold a variety of
reagent types including, but not limited to, mucolytic agents to
break-up mucus specimens, lysis buffer to burst cells and release
the contained genetic material, oligonucleotides, antibodies,
microspheres, magnetic beads, particles, and other reagent types.
In an embodiment, the actuation mechanism for propelling fluid into
the specimen collection chamber 407 includes a spring-actuated
piston 424 that is released upon the closing and first housing 402
toward the second housing 404. The spring-actuated piston 424 is
selected or designed to have the correct amount of energy to move
the gasket 422 an appropriate distance to dispense the fluid
contained in the leaching chamber reservoir 426 into the specimen
collection chamber 407.
[0054] FIG. 6 is a schematic illustration of a detecting portion of
a specimen delivery cartridge 500, which is analogous to the
specimen delivery cartridge 400 and specimen delivery cartridge 200
described above. The detecting portion is enclosed by a
super-structure, shown as housing 522. The super-structure of the
housing 522 may be a sub-housing or one contiguous piece of the
specimen delivery cartridge body. The housing 522 may be fabricated
from a plurality of materials including but not limited to plastic,
polymer, composite, metal or other materials. In some embodiments,
a reagent mixture consisting of the outputs from a given set of
assay protocols is deliverable as a fluid from the specimen
collection chamber through channel 502. The channel 502 is fluidly
coupled to and operable to receive fluid from an upstream specimen
collection chamber. A downstream portion of the channel 502 joins
to a splitter 503. The splitter 503 feeds one or more downstream
wicking channels, which may be hydrophilic wicking channels and are
shown as first downstream wicking channel 504, second downstream
wicking channel 506, third downstream wicking channel 508 (up to an
nth downstream wicking channel). Each of the downstream wicking
channels 504, 506, 508 are coupled to and operable to deliver fluid
onto a paper diagnostic 510 at interfaces 513, 515 up to the
n.sup.th interface 517 arranged upon the wicking channels 504, 506,
508 toward a wicking reservoir 518. The division of the original
fluid path into n separate wicking channels allows for more rapid
detection owing to parallelism, and the areal efficient design of a
paper diagnostic 510. The paper diagnostic 510 may be fabricated
from a variety of materials including but not limited to paper,
nitro-cellulose, and other materials with suitable wicking
properties. The paper diagnostic 510 is supported by a holder 512.
The holder 512 may be fabricated from a variety of materials
including but not limited to plastic, polymer, composite, metal,
glass or other suitable materials. In one embodiment, the paper
diagnostic is patterned into flow channels using an appropriate
hydrophobic material to confine fluid flow and prevent cross-talk
between adjacent channels.
[0055] FIGS. 6 and 7 illustrate the arrayed paper diagnostic 510,
which is an array of test areas arranged on a paper substrate, and
its position relative to an optical element 540. The housing of the
specimen delivery cartridge has been partially cut-away in the view
of FIG. 7 to allow for viewing of the internal components. The
cutaway view shows that the optical element 540 allows for high
quantum efficiency collection (and observation) of photons (light
or other electromagnetic radiation) emanating from the paper
diagnostic 510. The optical element may consist of some or all of a
combination of lenses, coatings, mirrors, diffractive elements,
filters, and other optical components. The optical element 540 is
supported by the element carrier 542 which may be fabricated from a
variety of materials to include but not limited to plastic,
polymer, composite, metal, or other suitable material.
[0056] In some embodiments, the optical element 540 is operable to
capture chemi-luminescent photon emission from the diagnostic
substrate 516 such that emitted light is reimaged onto the optical
sensor (CMOS/CCD/similar) of the computing device. The optical
element 540 may have one or more lenses and one or more filters. In
the illustrated embodiment, colored spots put an emission at a
colored wavelength, which may, for example, be on the visual or
infrared spectrum to facilitate detection. The emission is
indicative of a test result or detection of a pathogen. An optical
sensor, which may be included in the specimen delivery cartridge or
accessed using a computing device, is operable to detect the
emission to derive a test result. The configuration of the
substrate 516 and characteristics of locations on the test strip
520 of the substrate 516 may be configured to detect different
pathogens. In such an embodiment, the optical sensor, used in
conjunction with the specimen delivery cartridge is operable to
simultaneously detect multiple pathogens simultaneously by
detecting multiple wavelengths or multiple positions as a result of
previously placed reagents on the test strip 520. The optical
result may be stored and analyzed, and can be correlated to lookup
table to determine pathogens present.
[0057] FIGS. 8A and 8B show an illustrative embodiment of a digital
microfluidic (DMF) circuit with integrated reagent storage packs or
reservoirs 318, 320, 322, 324. The reagent storage packs or
reservoirs 318, 320, 322, 324 are positioned adjacent to
complimentary DMF electrodes 328, 330, 332, 334. The reagent
storage packs or reservoirs are operable to dispense metered
amounts of reagents on to the adjacent DMF electrode landing pad.
Subsequent to this action, the droplet of dispensed reagents on
each of the landing pads (electrodes 328, 330, 332, 334) may be
moved by electrowetting to other DMF electrodes where other steps
associated with a given assay protocol may be executed.
[0058] In some embodiments, the substrate 211 is either paper,
plastic or some other flexible material suitable for the printing
of a digital microfluidic circuit 326 pattern that uses conductive
inks to form the DMF drive electrodes 327 and the interconnects
562. Each interconnect couples an electrode to a drive circuit or
controller of a computing device via a pinout connector, as
described in more detail below. The DMF substrate 211 has alignment
holes 560, 561, 563, and 565 that mount on complimentary aligning
posts in the lower compartment (lower housing body) of the specimen
delivery cartridge. The DMF substrate 211 is folded around a rigid
material 566 such as plastic, cardboard, metal, glass, or other
suitable material so as to form an electrical connector 564
consisting of individual pin-outs comprised of their respective
interconnect line.
[0059] The electrical connector 564 is formed from the paper DMF
substrate 211 whereby backside interconnects 562 have been
fabricated to form the basis of "pin-out" connections to another
device. The backside interconnects (sometimes referred to as
interconnects) are printed on the backside 354 of the paper DMF
substrate 211 using conductive inks, and are bent around a rigid
material 566 to form the electrical connector 564 to mate with
complimentary pins of a connector of a receiving device, such as a
USB plug or port, or any other suitable port. The electrical
connector 564 may alternatively be referred to as a pinout
connector. The pinout connector 564 of the specimen delivery
cartridge has the advantage of being fabricated from traces that
are necessary as interconnects, but that can also serve the same
function as a separately installed off-the-shelf connector.
[0060] FIGS. 9A and 9B illustrate the implementation of backside
printing of interconnects to facilitate the increased areal density
of electrodes possible on the complimentary front side of the DMF
circuit, with FIG. 9A illustrating traditional areal density and
FIG. 9B illustrating increased areal density facilitated by
arranging the interconnect on the backside of the substrate. Each
may be formed using a specific printing process. The substrate 211
may again be paper, plastic, polymer or some other suitable
flexible material conducive to ink jet printing. For the embodiment
shown, the DMF electrodes 327 and interconnects are printed using
conductive inks and an ink jet (piezoelectric) printer. For the
case of DMF substrate 602, the DMF drive electrodes 327 and
interconnects 606 are printed on the same side of the substrate.
For the increased areal density of the embodiment of FIG. 9B,
interconnects 362 are printed on the backside of the substrate 211,
also using printed electronics from an ink jet printer with
conductive inks. As a direct consequence of printing the
interconnects 362 on the backside of the substrate 604, a higher
areal density of DMF drive electrodes 327 on the front side of the
substrate is achieved. The backside interconnects 362 and the front
side electrodes (or pads) electrically communicate by vias. The
vias are formed in cut-outs of the substrate and are filled with
conductive ink as part of a standard printing process and thereby
electrically connect the electrode pads 327 with the interconnects
362.
[0061] FIGS. 10A and 10B illustrate how a cut-out 620 may be formed
in the paper substrate 211 as the first step in the backside
interconnect manufacturing process to act as a via. In one
embodiment, the cut-out 620 is circular in shape; in other
embodiments the cut-out 620 may be square, rectangular, or one of
many other geometrical shapes. The cut-out 620 allows for
subsequent filling by a conductive ink which therefore establishes
the electrical conductivity between front side and back side.
[0062] FIGS. 11A and 11B illustrate the process for printing
backside interconnects 628. On a flat surface, the backside traces
are printed in accordance with the electrical circuit schematic
required. The cut-out 620 in the paper (also referred to as a
"via") will fill and become the planar surface for the subsequent
fabrication of the electrode (also referred to as a "pad" or a
"drive electrode"). The trace (also referred to as an interconnect)
will indicate a slight "sink-hole" effect as the conductive ink
fills in the cut-out hole. A single interconnect 624 is
electrically connected to the pad through the via. A planarizing
material is used on the side not being printed so as to create a
smooth surface at the cut-out 620. The smooth surface 620 mitigates
surface roughness of the DMF drive electrode, which may in some
cases be considered an undesirable attribute.
[0063] FIGS. 12A and 12B illustrate the process for printing
electrodes 630 on the front side of the substrate 211. The
electrodes 630 make electrical contact with the respective
interconnect 628 through the conductive ink contained in the via
620. The planarizing material is first removed and the substrate is
flipped over to the side intended for printing of DMF drive
electrodes. The drive electrodes 630 are now printed using an ink
jet printer with conductive inks following a desired pattern as may
be described by a standard file such as a Word document or a
Portable Document File format.
[0064] FIGS. 13A-13D shows schematic representation of a portion of
a process for analyzing a specimen using a digital microfluidic
(DMF) circuit 706, in which each square represents an electrode. In
FIG. 13A, a suspension of magnetic microspheres 702 is located on a
particular DMF electrode. The magnetic microspheres 702 may be
treated in a way that causes them to attract a target pathogen or
associated antibody for detection. In such manner, the microspheres
or with the microspheres may later be analyzed to determine whether
the target is present in the specimen. Similarly, a liquid that has
been interacted with the microspheres may be analyzed to determine
whether the target is present in the specimen if the liquid is
selected such that its properties will change in a detectable
manner if it interacts with the target (or indirectly with an
antibody or reagent that has interacted with the target).
[0065] In the embodiment of FIG. 13A, a droplet of buffer solution
704 is located on a second DMF electrode. A magnet 710, which may
be an electromagnet, is located underneath the DMF circuit
substrate (e.g., substrate 211) and is indicated by the dashed
circular trace. In one embodiment, the magnet is movable in a
direction perpendicular to the DMF substrate 211 by a mechanical
piston or similar movable member. The piston may be energized by a
motor of some type (such as a stepper motor) or it may be manually
moved by some action of the user. In another embodiment, the magnet
710 is an electromagnet that is energized by the flow of a
controlled current. In the embodiment shown, each 3.times.3 array
of electrodes is called a super node 708. The magnet 710 is located
underneath a super node 708. In one embodiment, a suspension of
magnetic microspheres 702 is located at a particular DMF electrode.
The magnetic microspheres may be suspended in a variety of reagents
such as phosphate buffered saline (PBS), deionized (DI) water,
polysorbate 20 (e.g., Tween), or other liquids. In another
embodiment, magnetic microspheres or micro-particles are first
injected into the vessel chamber by means of the leaching chamber,
whereby they are subsequently delivered to a DMF electrode, or to a
supernode 708, upon activation of the elution button by the
user.
[0066] In FIG. 13B, the microfluidic (DMF) circuit 706 is shown at
a first time in a schematic capturing of a time sequenced method of
macro-to-micro bridging as effected by the combined use of a DMF
circuit on a given substrate, magnetic microspheres, a magnet of
some particular description, and various reagents. At the first
time, an amount of specimen 722 is delivered on to the DMF
substrate at a supernode 708. In one embodiment, the specimen is a
clinical sample of some sort obtained from a human patient. For
example, the specimen in one case could be a nasopharyngeal swab
sample obtained by a clinician following standard clinical process.
In another embodiment, the specimen may be an environmental sample
obtained by a variety of standard methods (for example, a water
sample obtained with a pipelle, or a sample obtained by swabbing a
surface, etc.). This method accommodates a range of specimen
volumes of, for example, approximately 500 nL to 1 mL. For the
embodiment shown, the liquid suspension of magnetic microspheres
702 is moved by the technique of electro-wetting (by providing a
charge to sequentially arranged electrodes in sequence) from its
originating position to the center electrode of the supernode upon
which the specimen has been previously delivered. Not shown in the
figure is the next step of mixing the magnetic microspheres 702
with the specimen 722. Mixing occurs by first treating supernodes
as a single DMF drive electrode, meaning that all nine individual
electrodes of the supernode are biased at the same voltage and with
the same time sequencing. The next step in the mixing process is to
use adjacent supernodes to "shuttle" the now combined specimen,
magnetic microsphere and reagent mixture back and forth between
supernodes 708 (e.g., by moving the magnet 710 back and forth
between the supernodes 708). In this manner, the magnetic
microspheres become fully mixed and suspended in the entire
supernatant liquid.
[0067] In FIG. 13C, the microfluidic (DMF) circuit 706 is shown at
a second time subsequent to the first time referenced above with
regard to FIG. 13B. In the embodiment shown, the magnet 710 has
been positioned directly underneath the supernode 708 containing
the magnetic microspheres mixed with the specimen 722 and
supernatant solution. The magnetic field established by the magnet
710 pulls down the magnetic microspheres and specimen, which were
previously in liquid suspension, into a bolus of specimen-inclusive
magnetic microspheres in the center of the central individual DMF
drive electrode of the given supernode 708. At this point, through
the process of electro-wetting, the supernatant is removed to waste
leaving behind only the specimen-inclusive magnetic microspheres.
In one embodiment, the magnetic microspheres are washed by an
appropriate buffer solution by first moving a buffer droplet on to
the pad containing the bolus of specimen-inclusive magnetic
microspheres. The magnet 710 is removed and the droplet is shuttled
back-and-forth between adjacent pads so as to mix and re-suspend
the beads in the new solution. The re-suspended magnetic
microspheres in the buffer droplet are positioned at DMF pad 732
and the magnet 710 is reactivated so as to pull down the bolus of
magnetic microspheres. Subsequently, the second supernatant is
removed to waste using the process of electrowetting. This entire
process may be repeated as necessary. Ultimately, the final
condition will be a suspension of washed, specimen-inclusive
magnetic microspheres in an appropriate buffer solution of a volume
between, for example, approximately 500 nL to 500 mL.
[0068] In FIG. 13D, the microfluidic (DMF) circuit 706 is shown at
a third time (subsequent to the second time of FIG. 13B). FIG. 13D
shows the resuspension of the now washed specimen-inclusive
magnetic microspheres 742 in a pure buffer solution (such as PBS,
DI water, or some other appropriate reagent). The droplet size may
range from, for example, approximately 500 nL to 100 mL.
[0069] FIG. 14 is a flow chart further illustrating the process
1300 described above with regard to FIGS. 13A-13D. The process 1300
commences with suspension of magnetic beads onto a DMF substrate
1302, and dispensation of a buffer solution onto the substrate by a
plunger 1304. A magnet disposed adjacent the substrate is then
disengaged 1306, and subsequently all DMF electrodes making up a
first supernode are energized 1308. Next, the user presses an
actuating button to deliver eluted specimen to the supernode 1310.
Suspension of magnetic beads is the moved to a central electrode of
the supernode by electro-wetting. Subsequently a mixture of beads
and eluted specimen are shuttled between adjacent supernodes 1314
to mix the solution by alternating the actuation of a magnet
disposed adjacent each supernode. The magnets are then set to an
"on" position to generate an attractive force to pull down a bolus
of magnetic beads surrounded by a supernatant solution 1316. The
supernatant may be disposed to waste by electro-wetting while the
magnet remains engaged 1318. The buffer solution is then moved to
the location of the magnetic bead DMF electrode to re-suspend the
beads 1320. At this stage, the magnet may be set to an "off"
position 1322, and the specimen-inclusive magnetic microspheres may
be analyzed for the presence of a pathogen or other target.
[0070] FIG. 15 illustrates that a ground plane electrode 754 may be
formed on the lower surface of the lower intermediate member 208 to
act as a capacitive surface. In an embodiment, application of a
voltage to individual electrodes formed on the substrate 211 via
the microfluidic circuit 326 generates a controllable capacitance
at each electrode. In an embodiment, hydrophilicity of each of the
electrodes may be controllable by altering the voltage at each
electrode (e.g., electrodes 328, 330, 332, 334, described
previously) by using, for example, a computing device coupled to an
interconnect.
[0071] FIGS. 16A and 16B show a feature of a delivery mechanism of
reagents displaced from a specimen collection chamber 236 as and
delivered through a nozzle 752 onto a specific DMF electrode 336 of
the microfluidic circuit 326. The nozzle 752 is a feature that
facilitates the formation of a droplet of sample reagent from the
specimen collection chamber 236 to the underlying DMF electrode
336.
[0072] FIG. 17 shows an embodiment of a specimen delivery cartridge
1000 in which the testing substrate 1006 is formed to include a
hybrid DMF circuit using a combination of drive electrodes 1004
with a hydrophilic pad 1002. In such an embodiment, the hydrophilic
pad 1002 forms a test area of the substrate 1006, and does not
require electrical actuation to receive a droplet. Here, movement
of the droplet may instead be motivated by the hydrophilic
properties of a hydrophilic coating instead of the substrate 1006
(for example, a polytetrafluoroethylene, or "PTFE" coating) to coat
the test electrodes 1004. The hydrophilic pad 1002, which is
naturally hydrophilic, is similar to a PTFE coated electrode pad
that is always in the "ON" state (without any requisite electrical
actuation). Such hydrophilic pads 1002 would not require a ground
plate above them and are therefore suited to provide a clear line
of sight for imaging techniques that might be used to analyze a
test specimen. To that end, an optical interface 1010 is included
within an upper housing of the specimen delivery cartridge 1000 to
provide for optical inspection of the hydrophilic pad 1002
(analogous to the optical element described above).
[0073] Referring now to FIGS. 18 and 19, a two-stage specimen
delivery cartridge 1700 is shown. Like the specimen delivery
cartridge described above, the two-stage specimen delivery
cartridge 1700 includes an upper housing 1702 that is coupled to a
lower housing 1704 at a hinge. A vertical cross-section of the
two-stage specimen delivery cartridge 1700 is shown in FIG. 18. The
two-stage specimen delivery cartridge 1700 includes a specimen
collection chamber 1706 that is operable to receive a swab and is
analogous to the specimen collection chamber 236 described
previously with regard to the specimen delivery cartridge 200. To
that end, it is noted that analogous features of the specimen
delivery cartridges 200, 1700 may include the same or similar
attributes, and may not be discussed in more detail with regard to
the two-stage specimen delivery cartridge 1700 for brevity.
[0074] Like the specimen delivery cartridge 200, the two-stage
specimen delivery cartridge 1700 is configured to process specimens
(including without limitation swab-acquired specimens, urine,
blood, saliva, and other biological specimens) for subsequent
assaying using a paper diagnostic. To effect such assaying, an
elution buffer chamber 1708 is used to hold an appropriate reagent
that is, upon user activation of the plunger 1710 and button 1712,
dispensed under high pressure and therefore motivated at high
velocity into the specimen collection chamber 1706. The specimen
collection chamber 1706 and process for enclosing a specimen
therein may be functionally equivalent to the specimen delivery
chamber described above with regard to, for example, FIGS. 2 and 5.
The fluidic mixture, which now includes the reagent and specimen,
flows from the specimen collection chamber 1706 through an inlet
channel 1734 (shown partially in FIG. 18) that couples the specimen
collection chamber 1706 to a magnetic separation chamber 1714 thru
separation chamber inlet/orifice 1716.
[0075] The specimen delivery cartridge 1700 is also configured to
work with a mating adapter 1800, as shown in FIG. 18. In
processing, a selectively operable magnet 1802 (which may be an
electromagnet) located in the mating adapter 1800 pulls magnetic
micro-particles (e.g., microspheres) from the reagent out of
solution and holds them firmly on the bottom of the magnetic
separation chamber 1714. Upon depressing of a second button 1718
and second plunger 1720, the supernatant previously contained in
the magnetic separation chamber 1714 is propelled into a waste
reservoir 1736 (shown in FIG. 19). Depression of the second button
1718 and second plunger 1720 releases also an actuator 1724, which
in turn releases a holding sear pin 1726. Release of the sear pin
1726 results in actuation of a spring-loaded plunger 1728 to propel
fluid from a resuspension buffer chamber 1722 that is fluidly
coupled to the magnetic separation chamber 1714. A second reagent,
such as DI water, PBS, or another suitable fluid is thereby
propelled into the magnetic separation chamber 1714 to flow over
the bolus of magnetic microspheres held in place by the force of
the magnet 1802. A holding pin (not shown) is then released to
allow the magnetic separation chamber 1714, which is rotatable
within the housing, to rotate to open the separation chamber
inlet/outlet orifice 1716 to an absorption chamber 1754, thereby
allowing re-suspended magnetic microspheres to flow into the
absorption chamber 1754.
[0076] Once in the absorption chamber 1754, the liquid suspension
is absorbed by a wicking membrane 1730, which may be a
nitrocellulose membrane, and wicks toward a membrane reservoir 1732
as a result of capillary action of the membrane 1730.
[0077] In operation, the fluidic mixture having the specimen and
first reagent flow from the specimen collection chamber 1706
through a channel and into the magnetic separation chamber 1714
upon actuation of the first button 1710 and first plunger 1712. The
fluid enters the magnetic separation chamber 1714 through a
specimen fluid inlet corresponding to separation chamber
inlet/outlet orifice 1716. The magnetic separation chamber 1714 has
an inner cylinder 1738 that is rotatable within an outer cylinder
1740. Each of the inner cylinder 1738 and outer cylinder 1740 has
four openings, but only two of the four openings in each cylinder
are aligned at any given time. One or more of the openings may
include a check valve to limit the flow of fluid to a single flow
direction.
[0078] The aforementioned alignment is determined by the rotation
of the inner cylinder 1738 about its axis. It follows that the
inner cylinder 1738 may be in one of two rotational states. The
rotational state is controlled by a torsional spring positioned
beneath the magnetic separation chamber 1714 and coupled to the
base of the inner cylinder 1738. In a first position in which the
separation chamber inlet/outlet orifice 1716 is aligned with the
inlet channel 1734, the torsional spring has been displaced from
its equilibrium position and locked in place, storing elastic
potential energy. A waste fluid outlet 1742 and an outlet in the
outer cylinder 1740 that aligns with waste fluid channel 1744 are
also aligned when the inner cylinder 1738 is in the first position.
This allows for fluid to enter the magnetic separation chamber 1714
through the separation chamber inlet/outlet orifice 1716 upon
depression of the first button and to be displaced from the
magnetic separation chamber 1714 into the waste chamber 1736
through waste fluid outlet 1742 and an opening in the outer
cylinder 1740 aligned with the waste channel 1744 of the waste
chamber 1736.
[0079] The torsional spring is released and allowed to return to
its equilibrium position to rotate the inner cylinder 1738 into a
second position. When the inner cylinder 1738 is rotated into the
second position, a resuspension buffer inlet 1746 of the inner
cylinder 1738 is aligned with a resuspension buffer channel 1748
that forms a fluid flow path from the resuspension buffer chamber
1722 and through the outer cylinder 1740. Similarly, separation
chamber inlet/outlet orifice 1716 of the inner cylinder 1738 is
aligned with absorption chamber channel 1752 that forms a fluid
flow path through the outer cylinder 1740 to an absorption chamber
1754. In operation, this allows for fluid from the resuspension
buffer chamber 1722 to enter the magnetic separation chamber 1714
through the openings of the resuspension buffer inlet 1746 and
resuspension buffer channel 1748, and for the resuspension fluid to
leave the magnetic separation chamber 1714 through the openings of
the separation chamber inlet/outlet orifice 1716 and absorption
chamber channel 1752.
[0080] In prior operating steps, fluid from the specimen collection
chamber 1706 enters the magnetic separation chamber 1714 through
openings of the separation chamber inlet/outlet orifice 1716 and
inlet channel 1734. A magnet 1802 located in the mating adapter
1800 pulls magnetic micro-particles out of suspension and holds
them firmly on the bottom of the magnetic separation chamber 1714
while the inner cylinder 1738 is still in the first (pre-rotation)
position. Upon depressing the second button 1718, the supernatant
contained in the magnetic separation chamber 1714 is propelled into
the waste reservoir 1736 through openings corresponding to the
waste fluid outlet 1742 and waste fluid channel 1744. At the
completion of the depression of the 2.sup.nd button, an actuator
releases a holding sear pin that allows for the torsional spring
beneath the magnetic separation chamber 1714 to be released and the
inner cylinder 1738 to rotate into its second position. At the
completion of the rotation of the inner cylinder 1738 to the second
position, a second actuator releases a linear spring in the
resuspension buffer chamber 1722 that displaces the plunger 1728 in
the resuspension buffer chamber 1722, ejecting the resuspension
buffer from the resuspension buffer chamber 1722 and into the
magnetic separation chamber 1714 through openings corresponding to
the resuspension buffer inlet 1746 and resuspension buffer channel
1748. The resuspension buffer flows over the bolus of magnetic
beads in the magnetic separation chamber 1714, re-suspending them.
The momentum of the fluid carries the mixture through openings
corresponding to the separation chamber inlet/outlet orifice 1716
and absorption chamber channel 1752 and into the absorption chamber
1754. Once in the absorption chamber 1745, the liquid suspension is
absorbed by the membrane 1730 and wicks toward the absorbing
reservoir 1756 owing to capillary action.
[0081] As shown in FIG. 19, the absorption chamber 1754 of the
two-stage specimen delivery cartridge 1700 includes an absorbent
sponge that functions as an absorbing reservoir 1756. In some
embodiments, the absorbing reservoir 1756 is located at one end of
the membrane 1730, distal from the absorption chamber 1754. In such
embodiments, the membrane 1730 may also include a divergent wicking
fluidic circuit 1758 that diverges from the wicking path between
the absorbing reservoir 1756 and absorption chamber 1754. A holding
chamber 1760 is positioned at a terminal end of the divergent
wicking fluidic circuit 1758. In some embodiments, the holding
chamber 1760 contains a mixture of luminol and peroxide reagents.
These reagents of the holding chamber may be sealed in a blister
pack which bursts upon the user inserting the two-stage specimen
delivery cartridge 1700 into the mating adapter 1800, thereby
releasing the liquid reagent mixture to be absorbed by the membrane
1730 and begin wicking in accordance with the fluidic wicking
circuit.
[0082] The action of bursting the blister packs upon insertion of
the two-stage specimen delivery cartridge 1700 into the mating
adapter 1800 may be accomplished by posts on the mating adapter
1800 that protrude through an orifice in the lower housing 1704 the
of the two-stage specimen delivery cartridge 1700 when the
two-stage specimen delivery cartridge 1700 is properly positioned
for insertion into the mating adapter 1800. As the two-stage
specimen delivery cartridge 1700 is slid into the mating adapter
1800, the protruding posts contact and displace a plunger within
the holding chamber 1760. The displacement of this plunger causes
the blister packs to become compressed and burst under pressure,
allowing for the luminol and hydrogen peroxide reagents to be
further displaced by the plunger and into the holding chamber 1760
for absorption by the membrane 1730.
[0083] Upon contacting the membrane 1730, the reagents may
similarly wick toward the absorbent reservoir 1756 and interact
with the fluid wicking toward the absorbent reservoir 1756 from the
absorption chamber 1754. This interaction may occur, for example,
proximate to an optical interface 1762, providing for inspection
and analysis by a user directly, or using a computing device
through a corresponding mating adapter optical interface 1804 or
lens, as shown in FIG. 18.
[0084] In some embodiments, a preselected time delay may be desired
prior to the liquid from the holding chamber 1760 reaching the
wicking path between the absorption chamber 1754 and absorbent
reservoir 1756. To generate such a time delay, the divergent
wicking fluidic circuit 1758 may be directed along a circuitous
wicking path. Examples of circuitous wicking paths are described
with regard to the wicking devices of FIGS. 20 and 21. FIG. 20
illustrates a spiral wicking device 2100 having a first end 2102
and an opposing second end 2104, wherein the wicking device is
formed form a material that wicks fluid from the first end 2102 to
the second end 2104, or vice versa. In some embodiments, the spiral
wicking device 2100 has a coiled shape, like that of a coil spring.
The linear length of the spiral wicking device 2100 may be selected
to correspond to a desired time delay, and the height and pitch of
the spiral may be configured accordingly. When a liquid comes in
contact with the first end 2102 or second, opposing end 2104 of the
spiral wicking device 2100, the liquid is motivated by capillary
action of the wicking material to move in a circular motion toward
the opposite end of the wicking device 2100, while simultaneously
increasing (or decreasing) in elevation above the entry point.
[0085] FIG. 21 illustrates a bow-tie shaped wicking device 2200.
The bow-tie shape solves the problem of positioning a readout
surface corresponding to a first end 2202 of the wicking device
2200 for optimal interrogation by a detection modality. In an
embodiment, the wicking device 2200 includes a hydrophilic channel
2208 flanked by hydrophobic barriers at the periphery of the
wicking device 2200. The hydrophobic barriers define the shape of
the flow channel. The wicking device 2200 may receive fluid at a
second, opposing end 2204 from any of a variety of sources,
including another wicking element, a fluidic channel, or a liquid
dispensing element. As the fluid wicks along the hydrophilic
channel 2208, it encounters the bow-tie (or twist) 2206 which
changes the orientation of the wicking channel by 180 degrees for
optimal interrogation by a detection modality.
[0086] The above-disclosed embodiments have been presented for
purposes of illustration and to enable one of ordinary skill in the
art to practice the disclosure, but the disclosure is not intended
to be exhaustive or limited to the forms disclosed. Many
insubstantial modifications and variations will be apparent to
those of ordinary skill in the art without departing from the scope
and spirit of the disclosure. For instance, although the flowcharts
depict a serial process, some of the steps/processes may be
performed in parallel or out of sequence, or combined into a single
step/process. The scope of the claims is intended to broadly cover
the disclosed embodiments and any such modification.
[0087] As used herein, the singular forms "a", "an" and "the" are
intended to include the plural forms as well, unless the context
clearly indicates otherwise. It will be further understood that the
terms "comprise" and/or "comprising," when used in this
specification and/or the claims, specify the presence of stated
features, steps, operations, elements, and/or components, but do
not preclude the presence or addition of one or more other
features, steps, operations, elements, components, and/or groups
thereof.
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