U.S. patent number 6,436,632 [Application Number 09/970,578] was granted by the patent office on 2002-08-20 for multi-through hole testing plate for high throughput screening.
This patent grant is currently assigned to Genencor International, Inc.. Invention is credited to Amy Deming Liu, Volker Schellenberger.
United States Patent |
6,436,632 |
Schellenberger , et
al. |
August 20, 2002 |
Multi-through hole testing plate for high throughput screening
Abstract
A method for holding samples for analysis and an apparatus
thereof includes a testing plate with a pair of opposing surfaces
and a plurality of holes. Each of the holes extends from one of the
opposing surfaces to the other one of the opposing surfaces. The
holes are arranged in groups, where each group has at least two
rows and two columns of holes. The groups are arranged in sets,
where each set has at least two rows and two columns of groups. To
analyze samples, at least one of the opposing surfaces of the
testing plate is immersed in a solution to be analyzed. A portion
of the solution enters openings for each of the holes in the
immersed opposing surface. Once the holes are filled with solution,
the testing plate is removed and is held above a supporting
surface. Surface tension holds the solution in each of the holes.
The solution in one or more of the holes is then analyzed and the
solution in one of these holes is identified for further study. The
location of the identified solution is marked based upon its
location within a particular set and group of holes.
Inventors: |
Schellenberger; Volker (Palo
Alto, CA), Liu; Amy Deming (Mountain View, CA) |
Assignee: |
Genencor International, Inc.
(Palo Alto, CA)
|
Family
ID: |
26955315 |
Appl.
No.: |
09/970,578 |
Filed: |
October 4, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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528085 |
Mar 17, 2000 |
6306578 |
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471852 |
Dec 23, 1999 |
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272122 |
Mar 19, 1999 |
6027873 |
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Current U.S.
Class: |
435/4; 422/50;
435/30; 435/29; 422/68.1; 435/283.1 |
Current CPC
Class: |
B01J
19/0046 (20130101); B01L 3/5025 (20130101); B01L
3/5085 (20130101); B01L 3/50857 (20130101); B01L
2300/161 (20130101); B01J 2219/00317 (20130101); B01J
2219/00319 (20130101); B01J 2219/0052 (20130101); B01J
2219/00524 (20130101); B01J 2219/00659 (20130101); B01J
2219/00662 (20130101); B01J 2219/00707 (20130101); C40B
60/14 (20130101); G01N 35/1065 (20130101); G01N
2035/00237 (20130101); B01J 2219/00533 (20130101); B01J
2219/00596 (20130101); B01J 2219/00644 (20130101); B01L
2300/0654 (20130101); B01L 2300/0809 (20130101); B01J
2219/00286 (20130101) |
Current International
Class: |
B01J
19/00 (20060101); B01L 3/00 (20060101); G01N
35/00 (20060101); G01N 35/10 (20060101); C12Q
001/00 (); C12Q 001/02 (); C12Q 001/24 () |
Field of
Search: |
;435/4,283.1,29,30
;422/50,68.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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WO 97/37036 |
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Oct 1997 |
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WO |
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WO 99/34920 |
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Jul 1999 |
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WO |
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WO 00/56456 |
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Sep 2000 |
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WO |
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Other References
Arndt et al., A Rapid Genetic Screening System for Identifying
Gene-Specific Suppression Constructs for use in Human Cells,
Nucleic Acids Research, vol. 28, No. 6., pp. e15-i-viii (2000).
.
Rolls et al., A Visual Screen of GFP-Fusion Library Identifies a
New Type of Nuclear Envelope Membrane Protein, J. Cell Biol., vol.
146, No. 1, pp. 29-43 (1999). .
Sieweke, Direction of Transcription Factor Partners with a Yeast
One Hybrid Screen, Methods Mol. Biol., vol. 130, pp. 59-77 (2000).
.
Zhao et al., Directed Evolution Converts Subtilisin E into a
Functional Equivalent of Thermitase, Protein Eng., vol. 12, No. 1,
pp. 47-53 (1999)..
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Primary Examiner: Leary; Louise N.
Attorney, Agent or Firm: Kilyk & Bowersox, P.L.L.C.
Parent Case Text
CROSS REFERENCE TO THE RELATED APPLICATIONS
The present application is a continuation of prior U.S. patent
application Ser. No. 09/528,085, filed Mar. 17, 2000, now U.S. Pat.
No. 6,306,578, which in turn is a continuation-in-part of prior
U.S. patent application Ser. No. 09/471,852, filed Dec. 23, 1999,
now abanadoned which in turn is a continuation of U.S. patent
application Ser. No. 09/272,122, filed Mar. 19, 1999, now U.S. Pat.
No. 6,027,873 all of which are herein incorporated in their
entireties by reference.
Claims
What is claimed is:
1. An assembly for holding liquid samples, said assembly
comprising: a substrate having first and second opposing surfaces
and including a bundle of capillary tubes, wherein said first
opposing surface comprises first ends of the capillary tubes of
said bundle and said second opposing surface comprises said second
ends of the capillary tubes of said bundle; and a plurality of
through holes in said substrate, including longitudinally-extending
holes through the centers of the capillary tubes of said bundle,
each of said through holes extending from an opening in one of the
opposing surfaces of the substrate to an opening in the other of
the opposing surfaces, wherein the through holes are sized to
provide sufficient surface tension by capillary action to hold
respective liquid samples.
2. The assembly of claim 1, wherein said bundle further includes a
band that bounds the capillary tubes together.
3. The assembly of claim 2, wherein said band comprises metal,
plastic, glass, or an elastomeric compound.
4. The assembly of claim 1, wherein each capillary tube of said
bundle has a length between the first end and second end thereof
that is at least two times greater than the average diameter of
said capillary tube.
5. The assembly of claim 1, wherein each capillary tube of said
bundle has a length between the first end and second end thereof
that is at least four times greater than the average diameter of
said capillary tube.
6. The assembly of claim 1, wherein the average diameter of each
capillary tube is from about 0.001 millimeter to about one
millimeter.
7. The assembly of claim 1, wherein the length of each capillary
tube is from about one millimeter to about one centimeter.
8. The assembly of claim 1, wherein each capillary tube has a
capacity to hold from about 0.0001 microliter to about ten
microliters of liquid sample.
9. The assembly of claim 1, wherein said capillary tubes are fused,
bonded or adhered together in said bundle.
10. The assembly of claim 1, wherein said bundle of capillary tubes
comprises from about 100 to greater than 1,000 capillary tubes.
11. The assembly of claim 1, wherein said bundle of capillary tubes
comprises from about 500 to about 1,500 capillary tubes.
12. The assembly of claim 1, wherein said bundle of capillary tubes
has a circular cross-section.
13. The assembly of claim 1, wherein said bundle of capillary tubes
comprises a rectangular or square array of capillary tubes.
14. The assembly of claim 1, wherein said bundle of capillary tubes
includes capillary tubes arranged in rows and rows of capillary
tubes arranged in columns.
15. A method of providing a plurality of liquid samples, said
method comprising: providing the assembly of claim 1,: and at least
partially filling a plurality of said through holes with respective
liquid samples, wherein surface tension holds the respective liquid
samples in the respective plurality of through holes.
16. The method of claim 15, wherein said at least partially filling
comprises contacting at least one of the opposing surfaces of the
assembly with at least one liquid sample such that portions of said
at least one liquid sample at least partially fill a respective
plurality of said through holes.
17. The method of claim 16, further comprising, after said
contacting, separating the opposing surfaces of the assembly from
said liquid samples such that the surfaces are substantially free
of said liquid sample and the portions of said sample held within
the respective plurality of through holes are isolated from one
another.
18. The method of claim 17, wherein said contacting comprises
immersing at least one of said opposing surfaces into said at least
one liquid sample.
19. A method for identifying the location of a liquid sample in a
testing assembly, said method comprising: providing the assembly of
claim 1 wherein the capillary tubes are arranged in groups, and
each of the groups comprises at least two rows of through holes and
at least two columns of through holes, and wherein portions of the
liquid sample are located in at least some of the through holes;
identifying the liquid sample in at least one through hole; and
locating the identified through hole based upon the group in which
the through hole is located.
20. The assembly of claim 1, wherein a plurality of said capillary
tubes are filled with respective liquid samples each containing a
mixture of biological cells, and wherein at least one of said
liquid samples contains at least one analyte cell.
21. A high throughput screening method comprising: providing at
least one liquid sample that includes an analyte that directly or
indirectly produces a detectable characteristic; providing the
testing assembly of claim 1; at least partially filling a plurality
of said through holes with at least portions of said at least one
liquid sample, wherein surface tension holds the respective
portions in the respective plurality of through holes; and
detecting which of said plurality of through holes contains a
liquid sample portion that includes said analyte.
22. The method of claim 21, wherein said analyte is a biological
cell.
23. The method of claim 21, wherein said detectable characteristic
is a fluorescence or absorption characteristic.
24. The method of claim 21, wherein said analyte is at least one of
a mutant cell, a secretable protein, an enzyme, or a
microorganism.
25. An assembly for holding liquid samples for analysis, said
assembly comprising; a substrate having a pair of opposing
surfaces, and side edges; a plurality of through holes in the
substrate each of said through holes extending from an opening in
one of the opposing surfaces of the substrate to an opening in the
other of the opposing surfaces, said through holes being sized to
provide sufficient surface tension by capillary action to hold
respective liquid samples; and a handle connected to said substrate
for maneuvering said substrate.
26. The assembly of claim 25, wherein said handle is connected to
said substrate with bolts.
27. The assembly of claim 25, wherein an opening is provided in one
of said side edges, and an end of said handle is removably
positioned within said opening.
28. The assembly of claim 25, wherein said handle extends out from
the side of the substrate.
29. An assembly for holding liquid samples for analysis, said
assembly comprising: a substrate having a pair of opposing
surfaces; a plurality of through holes in the substrate, each of
said through holes extending from an opening in one of the opposing
surfaces of the substrate to an opening in the other of the
opposing surfaces, said through holes being sized to provide
sufficient surface tension by capillary action to hold respective
liquid samples; and a first evaporation plate secured to one of the
opposing surfaces of the substrate, and a second evaporation plate
secured to the other of said opposing surfaces of the substrate,
said evaporation plates being secured to said substrate to preserve
samples dispersed in the through holes from evaporation and
contamination.
30. The assembly of claim 29, wherein said evaporation plates are
secured to said substrate with clamps.
31. The assembly of claim 29, wherein said evaporation plates are
secured to said substrate with bolts.
32. The assembly of claim 29, wherein each of said opposing
surfaces includes a recessed portion and said plurality of through
holes are located in the recessed portions of the opposing
surfaces, and wherein the plurality of through holes in the
recessed portions are spaced away from facing surfaces of the
evaporation plates when the evaporation plates are secured to the
substrate.
33. An assembly for holding liquid samples for analysis, said
assembly comprising: a substrate having a pair of opposing
surfaces; and a plurality of through holes in the substrate, each
of said through holes extending from an opening in one of the
opposing surfaces of the substrate to an opening in the other one
of the opposing surfaces of the substrate, said through holes being
sized to provide sufficient surface tension by capillary action to
hold respective liquid samples, wherein a recessed portion having a
first depth is provided in a first opposing surface of said pair
and a protruding portion having a height is provided on the other
opposing surface of said pair, and wherein each of said plurality
of through holes extends from the recessed portion of said first
opposing surface to the protruding portion of the other opposing
surface, and said height is less than said depth.
34. A stackable system comprising two or more of the assemblies of
claim 33 stacked together, wherein the protruding portion of one of
the assemblies is received within the recessed portion of another
of the assemblies.
35. A system comprising two of the assemblies of claim 33 stacked
together and further comprising a spacer between the two stacked
assemblies.
36. A system comprising at least a first and a second assembly
stacked one on top of the other, each assembly comprising: a
substrate having a first opposing surface and a second opposing
surface; and a plurality of through holes in the substrate, each of
said through holes extending from an opening in the first opposing
surface of the substrate to an opening in the second opposing
surface of the substrate, said through holes being sized to provide
sufficient surface tension by capillary action to hold respective
liquid sample, and wherein said system further comprises an
evaporation plate disposed between said first assembly and said
second assembly, said evaporation plate having a first surface
facing the second opposing surface of said first assembly, and said
evaporation plate having a second surface facing the first opposing
surface of said second assembly, and wherein at least one of the
surfaces of said evaporation plate is provided with a recessed
portion to space the surface of the recessed portion from ends of
the through holes at one or both of the second opposing surface of
the first assembly and the first opposing surface of the second
assembly.
37. The system of claim 36, wherein the second opposing surface of
said first assembly is provided with a recessed portion.
38. The system of claim 36, wherein the first opposing surface of
said second assembly is provided with a recessed portion.
39. The system of claim 36, wherein both the first and second
surfaces of said evaporation plate are provided with a recessed
portion.
40. A system comprising at least a first and a second assembly
stacked one on top of the other, each assembly comprising: a
substrate having a first opposing surface and a second opposing
surface; and a plurality of through holes in the substrate, each of
said through holes extending from an opening in the first opposing
surface of the substrate to an opening in the second opposing
surface of the substrate, said through holes being sized to provide
sufficient surface tension by capillary action to hold respective
liquid sample, and wherein said system further comprises an
evaporation plate disposed between said first assembly and said
second assembly, said evaporation plate having a first surface
facing the second opposing surface of said first assembly, and said
evaporation plate having a second surface facing the first opposing
surface of said second assembly, and wherein at least one of the
second opposing surface of said first assembly and the first
opposing surface of said second is provided with a recessed portion
to space ends of the through holes at one or both of the second
opposing surface of the first assembly and the first opposing
surface of the second assembly, from the evaporation plate.
41. The system of claim 40, wherein the second opposing surface of
said first assembly is provided with a recessed portion.
42. The system of claim 40, wherein the first opposing surface of
said second assembly is provided with a recessed portion.
43. The system of claim 40, wherein both the second opposing
surface of said first assembly and the first opposing surface of
said second assembly are provided with a recessed portion.
44. The system of claim 40, wherein at least one of the first and
second surfaces of said evaporation plate is provided with a
recessed portion.
45. The system of claim 40, wherein a spacer is provide between the
evaporation plate and at least one of said first and second
assemblies.
46. A system comprising two or more assemblies stacked one on top
of the other, each assembly comprising: a substrate having a first
opposing surface and a second opposing surface; and a plurality of
through holes in the substrate, each of said through holes
extending from an opening in the first opposing surface of the
substrate to an opening in the second opposing surface of the
substrate, said through holes being sized to provide sufficient
surface tension by capillary action to hold respective liquid
sample, and wherein said system further comprises an evaporation
plate disposed between said first assembly and said second
assembly, said evaporation plate having a first surface facing the
second opposing surface of said first assembly, said evaporation
plate having a second surface facing the first opposing surface of
said second assembly, and wherein a spacer is provided between at
least one of the second surfaces of said evaporation plate and at
least one of the first and second assemblies, said spacer spacing
openings of the through holes away from the evaporation plate.
47. The system of claim 46, wherein a spacer is disposed between
the second opposing surface of said first assembly and the
evaporation plate.
48. The system of claim 46, wherein a spacer is disposed between
the first opposing surface of said second assembly and the
evaporation plate.
49. The system of claim 46, wherein at least one of said surfaces
of said evaporation plate is provided with a recessed portion.
50. A plate for holding samples of a solution with biological
material for analysis, said plate comprising; a platform having a
pair of opposing surfaces; and a plurality of holes in the
platform, each of said holes extending from an opening in one of
the opposing surfaces of the platform to an opening in the other
one of the opposing surfaces of the platform, each of the holes
being sized to hold biological material in said through holes by
surface tension; and wherein at least one of the opposing surfaces
is provided with a recessed portion.
51. The plate of claim 50, wherein both opposing surfaces are
provided with a recessed portion.
52. The plate of claim 50, wherein the plurality of holes contains
portions of a sample of a biological material, the biological
material includes cells, and each of the holes is sized to hold a
plurality of the cells.
53. The plate of claim 50, wherein the holes are arranged in groups
on the substrate, each of the groups comprises at least two rows of
holes and at least two columns of holes.
54. An assembly comprising two or more of the plates of claim 50
stacked one on top of the other.
55. The assembly of claim 54, wherein a spacer is provided between
at least two of the plates of said assembly.
56. The assembly of claim 54, wherein at least one of said plates
of said assembly is provided with a handle.
57. A high throughput screening method comprising: providing at
least one liquid sample that includes an analyte that directly or
indirectly produces a detectable characteristic in one or more of
an absorbance transcription assay, a fluorescent transcription
assay, a fluorescent secreted enzyme assay, and a microorganism
screening assay; providing the assembly of claim 1; at least
partially filling a plurality of said through holes of said
assembly with at least portions of said at least one liquid sample,
wherein surface tension holds the respective portions in the
respective plurality of through holes; and detecting which of said
plurality of through holes contains a liquid sample portion that
includes said analyte.
58. The method of claim 57, wherein said detectable characteristic
is produced in an absorbance transcription assay.
59. The method of claim 57, wherein said detectable characteristic
is produced in a fluorescent transcription assay.
60. The method of claim 57, wherein said detectable characteristic
is produced in a fluorescent secreted enzyme assay.
61. The method of claim 57, wherein said detectable characteristic
is produced in a microorganism screening assay.
62. A high throughput screening method comprising: providing at
least one liquid sample that includes an analyte that directly or
indirectly produces a detectable characteristic in one or more of
an absorbance transcription assay, a fluorescent transcription
assay, a fluorescent secreted enzyme assay, and a microorganism
screening assay; providing the assembly of claim 25; at least
partially filling a plurality of said through holes with at least
portions of said at least one liquid sample, wherein surface
tension holds the respective portions in the respective plurality
of through holes; and detecting which of said plurality of through
holes contains a liquid sample portion that includes said
analyte.
63. The method of claim 62, wherein said detectable characteristic
is produced in an absorbance transcription assay.
64. The method of claim 62, wherein said detectable characteristic
is produced in a fluorescent transcription assay.
65. The method of claim 62, wherein said detectable characteristic
is produced in a fluorescent secreted enzyme assay.
66. The method of claim 62, wherein said detectable characteristic
is produced in a microorganism screening assay.
67. A high throughput screening method comprising: providing at
least one liquid sample that includes an analyte that directly or
indirectly produces a detectable characteristic in one or more of
an absorbance transcription assay, a fluorescent transcription
assay, a fluorescent secreted enzyme assay, and a microorganism
screening assay; providing the assembly of claim 29; at least
partially filling a plurality of said through holes with at least
portions of said at least one liquid sample, wherein surface
tension holds the respective portions in the respective plurality
of through holes; and detecting which of said plurality of through
holes contains a liquid sample portion that includes said
analyte.
68. The method of claim 67, wherein said detectable characteristic
is produced in an absorbance transcription assay.
69. The method of claim 67, wherein said detectable characteristic
is produced in a fluorescent transcription assay.
70. The method of claim 67, wherein said detectable characteristic
is produced in a fluorescent secreted enzyme assay.
71. The method of claim 67, wherein said detectable characteristic
is produced in a microorganism screening assay.
72. A high throughput screening method comprising: providing at
least one liquid sample that includes an analyte that directly or
indirectly produces a detectable characteristic in one or more of
an absorbance transcription assay, a fluorescent transcription
assay, a fluorescent secreted enzyme assay, and a microorganism
screening assay; providing the assembly of claim 33; at least
partially filling a plurality of said through holes with at least
portions of said at least one liquid sample, wherein surface
tension holds the respective portions in the respective plurality
of through holes; and detecting which of said plurality of through
holes contains a liquid sample portion that includes said
analyte.
73. The method of claim 72, wherein said detectable characteristic
is produced in an absorbance transcription assay.
74. The method of claim 72, wherein said detectable characteristic
is produced in a fluorescent transcription assay.
75. The method of claim 72, wherein said detectable characteristic
is produced in a fluorescent secreted enzyme assay.
76. The method of claim 72, wherein said detectable characteristic
is produced in a microorganism screening assay.
77. A high throughput screening method comprising: providing at
least one liquid sample that includes an analyte that directly or
indirectly produces a detectable characteristic in one or more of
an absorbance transcription assay, a fluorescent transcription
assay, a fluorescent secreted enzyme assay, and a microorganism
screening assay; providing the plate of claim 50; at least
partially filling a plurality of said through holes with at least
portions of said at least one liquid sample, wherein surface
tension holds the respective portions in the respective plurality
of through holes; and detecting which of said plurality of through
holes contains a liquid sample portion that includes said
analyte.
78. The method of claim 77, wherein said detectable characteristic
is produced in an absorbance transcription assay.
79. The method of claim 77, wherein said detectable characteristic
is produced in a fluorescent transcription assay.
80. The method of claim 77, wherein said detectable characteristic
is produced in a fluorescent secreted enzyme assay.
81. The method of claim 77, wherein said detectable characteristic
is produced in a microorganism screening assay.
Description
FIELD OF THE INVENTION
This invention is related generally to a testing apparatus and,
more particulary, to a multi-through hole testing plate for high
throughout screening.
BACKGROUND OF THE INVENTION
Prior testing apparatuses have consisted of a testing plate with a
pair of opposing surfaces and plurality of wells. The wells extend
in from one of the opposing surfaces, but do not extend through to
the other opposing surfaces. The wells are used to hold samples of
solution to be analyzed.
Although these testing apparatuses work there are some problems.
For example, the wells in these testing apparatuses are difficult
to fill. Special delivery systems, such as large pipette systems,
are needed to fill each of the wells with samples of solution.
These special delivery systems are often expensive and difficult to
operate. As a result, the overall cost of the testing procedure is
increased.
Another problem with these prior testing apparatuses is with their
construction. The bottom of the wells in these testing plates need
to be transparent so that light can be transmitted through the
samples during testing. However, the rest of the testing plate
needs to be constructed of a non-transparent material. The
construction of a testing apparatus with these characteristics is
difficult and expensive.
Yet another problem with these prior testing apparatuses is with
the operator locating a particular well in the testing apparatus.
Typically, these testing apparatuses each include large numbers of
wells which are equidistantly spaced apart. As a result, locating a
particular well within the large number of wells is difficult.
Accordingly, there is a need for an improved testing apparatus for
high throughput screening.
SUMMARY OF THE INVENTION
A method for holding samples in accordance with one embodiment of
the present invention includes several steps. First, a testing
plate with a pair of opposing surfaces and a plurality of holes is
provided. Each of the holes extends from one of the opposing
surfaces to the other one of the opposing surfaces. Next, at least
one of the opposing surfaces of the testing plate is immersed in a
solution to be analyzed. A portion of the solution enters openings
for each of the holes in the immersed opposing surface and any
gases in the holes escape though openings for each of the holes in
the other opposing surface. Next, the testing plate is removed from
the solution. Surface tension holds some of the solution in each of
the holes. The opposing surfaces of the testing plate are then held
above a supporting surface and the solution held in at least one of
the holes is analyzed.
A method for identifying the location at least one sample of a
solution in accordance with another embodiment of the present
invention includes several steps. First, a testing plate with a
pair of opposing surfaces and a plurality of holes is provided.
Each of the holes in the testing plate extend from one of the
opposing surfaces to the other one of the opposing surfaces. The
holes in the plate are arranged in groups. Each of the groups
comprises at least two rows and two columns of holes. Once a
testing plate has been provided, solution is loaded into the holes
and is then analyzed. Based on this analysis, the solution in at
least one hole is identified for further study. The location of the
identified hole is marked based upon the group in which the hole is
found.
A method for screening a sample in accordance with another
embodiment of the present invention includes several steps. First,
a solution of the sample is prepared for screening. Next, a testing
plate with a pair of opposing surfaces and a plurality of holes is
provided. Each of the holes extends from one of the opposing
surfaces to the other one of the opposing surfaces in the testing
plate. Next, at least one of the opposing surfaces of the testing
plate is immersed in a solution. A portion of the solution enters
openings for each of the holes in the immersed opposing surface of
the testing plate. Once the solution has enter into the holes, the
testing plate is removed from the solution and the surface tension
holds at least some of the solution in the holes. Next, the
solution in one or more of the holes is analyzed.
An apparatus for holding samples of a solution with cells for
analysis in accordance with another embodiment of the present
invention includes a testing plate with a pair of opposing surfaces
and a plurality of through holes. Each of the holes extends from an
opening in one of the opposing surfaces in the testing plate to an
opening in the other one of the opposing surfaces and is sized to
hold a plurality of the cells. A portion of at least one of the
opposing surfaces of the testing plate where the holes are located
is recessed so that the openings in the testing plate are spaced in
from the opposing surface.
An apparatus for holding samples for analysis in accordance with
yet another embodiment of the present invention also includes a
testing plate with a pair of opposing surfaces and a plurality of
holes. Each of the holes extends from one of the opposing surfaces
to the other one of the opposing surfaces. The holes are arranged
in groups on the testing plate, where each of the groups comprises
at least two rows and two columns of holes.
The method and apparatus for holding samples for analysis in
accordance with the present invention provides a number of
advantages. For example, the present invention simplifies testing
procedures. The samples of solution to be analyzed can be loaded
into the testing plate by simply dipping or flooding one of the
surfaces of the testing plate into the solution. As a result, the
present invention does not require the use of a separate delivery
systems for loading solution into the wells on the testing
plate.
The present invention also simplifies the construction of the
testing apparatus. The testing apparatus merely needs one of the
opposing surfaces of the testing apparatus to be spaced away by
additional spacers or machined to create a recessed portion and
then a plurality of holes need to be drilled through the plate in
the recessed portion. Unlike prior testing apparatuses, the present
invention does not require any special construction techniques to
male the bottom of the wells transparent because the holes extend
all of the way through the plate.
The present invention also permits an operator to more easily
identify a particular hole filled with a sample for further
analysis. Instead of spacing the holes equidistantly over the
testing plate, the present invention arranges the holes in groups
of at least two columns and two rows of holes and arranges the
groups in sets of at least two or more. The groups are spaces
further apart then the holes within each group and sets of groups
are spaced further apart then the groups are spaced apart. As a
result, an operator can more easily identify a particular hole
based upon which set, group, row, and column the hole is located in
on the testing plate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of a multi-through hole testing plate in
accordance with one embodiment of the present invention;
FIG. 2 is a cross-sectional view of the multi-through hole testing
plate shown in FIG. 1 taken along lines 2--2;
FIG. 3 is a perspective, exploded view of another multi-through
hole testing plate in accordance with the present invention between
a pair of evaporation plates;
FIG. 4 is a block diagram of a testing apparatus with a
multi-through hole testing plate in accordance with another
embodiment of the present invention;
FIG. 5 is a top view of the multi-through hole testing plate in
accordance with another embodiment of the present invention;
FIG. 6 is a cross-sectional view of the multi-through hole testing
plate shown in FIG. 5 taking along the lines 6--6;
FIG. 7 is a top view of a multi-through hole testing plate in
accordance with yet another embodiment of the present
invention;
FIG. 8 is a top view of a testing plate assembly according to an
embodiment of the present invention; and
FIG. 9 is a perspective view of the assembly of FIG. 8 shown in
partial cut-away.
DETAILED DESCRIPTION
A testing apparatus 10 in accordance with one embodiment of the
present invention is illustrated in FIG. 1. The testing apparatus
10 includes a testing plate 12 with a pair of opposing surfaces 14
and 16 (surface 16 is shown in FIG. 2) and a plurality of through
holes 18. The through holes 18 are located in recessed portions 20
and 22 on each side of the testing plate 12. The through holes 18
are also arranged in groups 24 of at least two columns and two rows
of holes 18 and in sets 26 of two or more groups of holes 18. The
testing apparatus 10 provides a number of advantages including
simplifying the procedure for loading samples of solution S into
the holes 18 in the testing apparatus 10, simplifying the
construction of the testing apparatus 10, and making the
identification of a particular hole 18 filled easier for an
operator.
Referring to FIGS. 1 and 2, the testing apparatus 10 includes the
testing plate 12 which in this particular embodiment is made of a
non-transparent material, such as aluminum and polypropylene,
although other types of materials, such as teflon, polystyrene,
stainless steel, polythylene, any metal or plastic, can be used.
The testing plate 12 could also be made of transparent materials,
such as glass of transparent plastic, when non-optical means are
used for analysis, such as analyzing the materials blotted on
membranes.
The testing plate 12 includes the pair of opposing surfaces 14 and
16. In this particular embodiment, the opposing surfaces 14 and 16
are substantially planar, except where the recessed portions 20 and
22 are located, although the surfaces 14 and 16 could have other
relationships with respect to each other. Each of the opposing
surfaces 14 and 16 includes one of the recessed portions 20 and 22
which are machined into the testing plate 12, although other
techniques for forming the recessed portions 20 and 22, such as by
molding or adding spaces, can be used. When either of the opposing
surfaces 14 and 16 of the testing plate 12 rests on a supporting
surface 28, the recessed portion 14 or 16 along with the plurality
of holes 18 located in the recessed portion 14 or 16 are spaced
away from the supporting surface 28. If openings 30 and 32 to the
holes 18 contacted the supporting surface 28, then any solutions in
the holes 18 would drain out of the holes 18. In this particular
embodiment, a ridge 34 if formed in each of the opposing surfaces
14 and 16 by the recessed portions 20 and 22 which extends around
the outer circumference of the testing plate 12. Although the holes
18 are spaced from the support surface 28 by a recessed portion 20
or 22 formed in the testing plate 12, the holes 18 can be spaced
from the supporting surface 28 with other types of supporting
structures, such as a bracket attached to the testing plate which
supports the testing plate 12 and holes 18 above the supporting
surface 28.
Referring to FIGS. 5 and 6, another testing apparatus 50 in
accordance with one embodiment of the present invention is
illustrated. The testing apparatus 50 is identical to the test
apparatus 10 shown in FIGS. 1 and 2 except that the testing
apparatus 50 does not include a pair of recessed portions. Instead,
the testing apparatus 50 has a recessed portion 52 and a protruding
portion 54. When the testing plate 51 is placed on a supporting
surface, the recessed portion 52 must be facing the supporting
surface so that the holes are spaced from the supporting surface.
Although one example of the testing apparatus 50 is shown, the
opposing surfaces of the testing plate 51 could have other
configurations. For example, protruding portion 54 could be made
flush with the upper surface of testing plate 51.
Referring to FIGS. 1-3, the testing plate 12 also includes an
optional handle 36 and an opening 38 on one side of the testing
plate 12 to receive one end of the handle 36, although other
techniques for connecting the handle 36 to the testing plate 12 can
be used, such as connecting the handle 36 with bolts. The handle 36
extends out from the side of the testing plate 12 and is used to
maneuver the testing plate 12 during loading and testing.
A plurality of through holes 18 are located in the testing plate
12. The holes 18 extend from openings 30 in the recessed portion 20
of one of the opposing surfaces 14 to openings 32 in the recessed
portion 22 of the other opposing surface 16. In this particular
embodiment, the holes 18 have a substantially cylindrical shape,
although the holes 18 could have other shapes, such as a hexagonal
cross-sectional shape or a cone shape. In this particular
embodiment, each of the holes 18 has a diameter of about one
millimeter and can hold about hold about 5.5 microliters of
solutions S and cells C, although the diameter, volume and number
of cells C each hole 18 can hold can vary as needed or desired. The
solution S along with cells C in the solution S are held in the
holes 18 by surface tension as shown in FIG. 4. More specifically,
the size of the holes 18 may need to change depending upon the
solution S to be analyzed and that solution's surface tension
properties. For example as understood by one of ordinary skill in
the art, a buffer solution might have different surface tension
properties than a culture media containing salt. There must be
sufficient surface tension to keep the samples of solution S in the
holes 18.
One of the advantages of the present invention is that the testing
plate 12 is easy to manufacture. A plate having opposing surfaces
can have an appropriate number of holes drilled there through. The
plate can include one or more recessed portions 20, 22, and the
through holes can pass through the recessed portion of the plate
12. Since the holes 18 extend all of the way through, there is no
need for a transparent bottom in each hole 18. Light transmitted
into the holes 18 will pass through during testing. With prior
wells, the testing apparatus also needed to be non-transparent, but
since the wells did not extend through the apparatus, the bottom of
the wells needed to be made of a transparent material to permit
light to pass through the sample for optical analysis. Constructing
these prior testing apparatuses was difficult and expensive.
Referring to FIG. 1, the testing plate 12 has about two-thousand
holes 18 which extend through from one opposing surface 14 to the
other opposing surface 16, although the number of holes 18 can vary
as needed or desired. To assist an operator in identifying a
particular hole 18 in this particular embodiment the holes 18 are
arranged in groups and sets of holes 18. Each group 24 contains at
least two rows and two columns of holes 18 and each set 26 includes
at least two rows and two columns of groups 24. In this particular
embodiment, each group 24 of holes 18 and five rows and five
columns of holes 18 and there are eighty groups 24 of twenty-five
holes 18 in this example, although the number can vary as needed or
desired. The holes 18 in this example are spaced about 1.5 mm apart
between rows of holes 18 and between columns of holes 18 within
each group 24, although this distance can vary and the spacing
between rows of holes 18 and columns of holes 18 within each group
24 can be different as needed or desired. In this particular
embodiment, each set of groups 24 includes two rows of groups 24
and ten rows of groups 24 and there are four sets 26 which contain
twenty groups 24 of holes 18 each in this example, although the
number can vary as needed or desired. The groups 24 within a set 26
in this example are spaced about 2.0 mm apart and the sets 26 of
groups 24 of holes 18 in this example are spaced about 2.5 mm
apart, although these distances can vary as needed or desired.
By arranging the holes 18 in sets 26 and groups 24, it is much
easier for an operator to identify a particular hole 18 in the
testing plate 12 and retrieve a particular sample. The sets 26 of
holes 18 help the operator identify the general area of the hole 18
and then the groups 24 help the operator to begin to narrow down
the location of the hole 18. The column and row of the hole 18 in
each group 24 provides the precise location of the hole 18. The
spacing between sets 26, groups 24, and rows and columns are
different to make it visually easier for an operator to identify a
particular hole 18. When the holes 18 are all spaced equidistantly
apart, then it is more difficult to identify a particular hole 18
and it is easier for an operator to lose his/her place and select a
sample from the wrong hole 18.
Although the holes 18 are arranged in groups 24 and sets 26 in
testing apparatuses 10 and 50 to aid human operators, other
arrangements for the holes 18 may also be used. For example, when
the testing apparatuses are used by robotics, instead of human
operators, the holes 18 can also be spaced equidistantly apart as
shown in the embodiment of the testing apparatus 60 illustrated in
FIG. 7. The testing apparatus 60 is identical to the testing
apparatuses 10 and 50 described and illustrated earlier except for
the that the holes 18 are equidistantly spaced apart.
Referring to FIG. 3, the testing apparatus 10 may also include a
pair of optional evaporation plates 40 and 42. The evaporation
plates 40 and 42 are each secured to the one of the opposing
surfaces 14 and 16 of the testing plate 10. The evaporation plates
40 and 42 are secured to the testing plate 12 by bolts, clamps, or
other mechanical means. When the evaporation plates 40 and 42 are
secured to the testing plate 12 over the recessed portions 20 and
22, the recessed portions 20 and 22 in the opposing surfaces 14 and
16 of the testing plate 12 still space the openings 30 and 32 of
the through holes 18 away from the evaporation plates 40 and 42.
The evaporation plates 40 and 42 help to preserve the samples of
solution S in the holes 18 in the testing plate 12 from evaporation
and contamination.
Instead of a recessed portion in the plate 12, an assembly
comprising the plate and evaporation plates can be provided with
spacers between the testing plate and the evaporation plates to
space the openings of the through holes away from the evaporation
plates. The evaporation plates could be provided with recesses
portions in addition to, or instead of, spacers between the testing
plate and the evaporation plates. Any combination of recessed
portions in the testing plate, recessed portions in the evaporation
plates, or spacers can be used to provide the spacing between the
openings of the through holes and the evaporation plates.
According to an embodiment of the present invention, stackable
testing plates are provided which may or may not have evaporation
plates in-between testing plates. The stackable testing plates may
be provided with recessed portions or evaporation plates with
recessed portions can be provided between a stacked testing plate.
Any combination of recessed portions in the testing plates,
recessed portions in the evaporation plates, or spacers can be used
to provide a stack of testing plates wherein each testing plate is
spaced from the surface of an adjacent testing plate, evaporation
plate, or both.
One example of one application of the present invention will be
discussed with reference to testing apparatus 10 shown in FIGS.
1-4. In this particular example, cells C are mutagenized using
ultraviolet, chemical mutagenesis, or other mutagenesis technology.
The cells C are grown to allow for segregation. Once the cells C
have grown, the cells C are diluted to one cell C per ten
microliters in a medium containing a fluorgenic or chromogenic
substrate. For purposes of this example, the medium with the cells
C is referred to as the solution S. As a result, the cells will be
randomly distributed in the holes 18 and many of the holes 18 will
contain one or more cells C.
Although one example of preparing the solution S and cells C is
disclosed, other methods and techniques for preparing samples to be
used with the testing apparatus 10 can be used as is readily
understood by one of ordinary skill in the art.
Next, a testing plate 12 with a pair of opposing surfaces 14 and 16
and a plurality of holes 18 which extend from one of the opposing
surfaces 14 to the other one of the opposing surfaces 16 is
provided. At least one of the opposing surfaces 14 of the testing
plate is immersed in the prepared solution S. The solution S enters
openings 30 and 32 for each of the holes 18 in testing plate 12 and
any gases in the holes 18 may escape through openings 30 and 32 at
the opposite end of the holes 18. Alternatively, the testing plate
12 may be flooded with solution S so that the solution S enters
through the top opening 30 to each hole 18.
One of the advantages of the present invention is the ease with
which solution S can be loaded into each of the holes 18. As
illustrated in the description above, all of the holes 18 in the
testing plate 12 can be loaded with samples of solution S in a
relatively short period of time and without any type of specialized
solution delivery system. Prior testing apparatuses with wells
required specialized solution delivery system, such as large
pipette devices, to be able to load solution into each of the
wells. These specialized solution delivery systems are difficult to
use and are expensive.
Once the solution S has been drawn into the holes 18, the testing
plate 12 is removed from the solution S. Surface tension holds the
solution S in each of the holes 18. In this particular embodiment,
each hole 18 has a diameter of about one millimeter and holds about
5.5 microliters of solution S and cells C as shown in FIG. 4,
although the diameter and volume of each hole 18 can vary as needed
or desired for the particular application. The handle 36 can be
used to manipulate the position of the testing plate 12 during the
above-described operations.
Once the testing plate 12 is removed from the solution S, the
testing plate 12 can be placed on a supporting surface 28. Since
the holes 18 are located in a recessed portion 22 of the testing
plate 12, the openings 22 to the holes 18 are spaced from the
supporting surface 28 so that any solution S being held by surface
tension remains in the holes 18. A pair of evaporation plates 40
and 42 may be attached to the opposing surfaces 14 and 16 of the
testing plate 12 to prevent the samples of solution S in the
testing plate 12 from evaporating or becoming contaminated.
In this particular example, the testing plate 12 is then optionally
incubated at a controlled temperature of about 37.degree. C. and a
humidity of about 70%, although the temperature and humidity will
vary based upon the particular application. During the incubation,
the cells multiply and produce a protein of interest (the cells
could produce an enzyme, an antibody, or a metabolite which could
be of interest). The ability of the protein, such as an enzyme, to
hydrolyze a substrate is analyzed, such as by measurement of
fluorogenic or chromogenic groups liberated by the hydrolysis.
Although one example of processing the samples of solution S in the
testing plate 12 is disclosed, other methods and techniques for
processing and analysis the samples can also be used and are know
to those of ordinary skill in the art.
Next, in this particular example the samples of solution S with
cells C in the holes 18 (as shown in FIG. 4) are tested using an
image analyzer with a light source 44 and a detector 46 in this
particular example. Light is transmitted from the light source 44
towards the openings 30 for the holes 18 in the testing plate 12
and through the solution S in the holes 18 of the testing plate 12.
The detector 46 is positioned on the opposing side of the testing
plate 12 and detects the light which has been transmitted through
the solution S in the holes 18. Based upon the changes in the
detected light from the transmitted light, information about the
characteristics of the particular samples of solution S can be
determined in a manner well known to those of ordinary skill in the
art. In this particular example, the image analyzer is able to
determine which holes 18 contain solution S with the highest
concentration of converted substrate and consequently the highest
amount of enzyme. The target in this case is to retrieve the cells
C which produced the largest amount of enzyme. In a similar way,
cells C which produced the largest amount of a protein or a
chemical of interest could be identified.
Although one example of analyzing the samples of solution S in the
testing plate 12 using optics is disclosed, other methods and
techniques for analyzing the samples, such as non-optical methods,
can also be used. For example, a plate containing samples of
solution S with cells C could be blotted onto a membrane and used
for performing Western blot analysis or alternatively, the samples
S with cells C could be blotted onto substrate containing material
whereby modification of the substrate is measured visually. As a
result, when non-optical means are used to analyze the samples of
solution in the testing plate 12, the testing plate 12 can be made
of a transparent material.
Next, in this particular example the operator retrieves the samples
of solution S which contain the highest concentration of converted
substrate. The holes 18 with the solution S with the highest
concentration of converted substrate can be identified and located
based upon which set 26 of groups 24, which group 24, and which row
and column within each group 24 each identified hole 18 is located.
One of the advantages of the present invention is the arrangement
of the holes in groups 24 and sets 26 which enables an operator to
easily identify a particular hole 18 on the testing plate 12. Once
the desired samples are retrieved, the operator can conduct further
analysis on those samples in manners well known to those of
ordinary skill in the art.
Although one example of retrieving one or more of the samples of
solution S in the testing plate 12 is disclosed, other methods and
techniques for retrieving samples can also be used. For example, if
robotics are used to located and retrieve a particular sample, a
different testing apparatus, such as testing apparatus 60 shown in
FIG. 7, could be used. The robotics would not need the holes 18 to
be arranged in groups 24 and sets 26 of holes 18, although such an
arrangement may even aid the robotics in identifying and retrieving
the desired sample.
According to some embodiments of the present invention, the testing
plate is in the form of an assembly or substrate. For example, the
plate can comprise a plurality of individual components which
together make up an assembly having opposing surfaces and a
plurality of through holes extending from one surface to the other.
An example of the present invention wherein the testing plate
comprises such an assembly is a plate made of a bundle of capillary
tubes as shown in FIGS. 8 and 9.
As shown in FIGS. 8 and 9, a plate, substrate or assembly 70
comprises a bundle of capillary tubes 72 bound together by a band
74. The through holes of the assembly according to this embodiment
are the longitudinally-extending holes through the center of each
capillary tube. The band 74 may have opposing surfaces 76 and 78,
each of which is substantially planar and substantially parallel to
the other. The band can be made of metal, plastic, glass, rubber,
elastomeric compound, or any other suitable material. Each
capillary tube 72 has a first end 80 and a second end 82. The first
ends 80 of the capillary tubes make up an opposing surface 84 of
the substrate or assembly 70 and the second ends 82 of the
capillary tubes 72 made up an opposing surface 86 of the substrate
or assembly.
As can be seen in FIGS. 8 and 9, each capillary tube 72 of the
bundle which makes up substrate or assembly 70 has a length between
its first end 80 and its second end 82 which is at least two times
greater than the average diameter of each tube. Preferably, the
length of each tube is more than four times greater than the
average diameter of each tube and is preferably many times greater
than the average diameter. Each capillary tube may be, for example,
in the form of a microcapillary tube or a hollow fiberoptic
fiber.
The capillary tubes may be hollow cylindrical in shape or may have
other rounded, oval, or polygonal cross-sections. The average
diameter of each capillary tube preferably ranges from about 0.001
millimeter to about 1 millimeter, and the length of each tube
preferably ranges from about 1 mm to about 1 cm. The dimensions of
the capillary tubes are preferably such that each tube has the
capacity to hold from about 0.0001 microliter to about 10
microliters of liquid sample, for example, about 5.5 microliters,
although the diameters, lengths, and holding capacities of the
capillary tubes may vary as needed or desired. According to some
embodiments of the present invention, it is not necessary to have a
band for holding the capillary tubes together in a bundle as the
tubes may instead be fused or otherwise bonded, adhered, or
maintained together in a bundle.
The number of capillary tubes of the embodiment in FIGS. 8 and 9 is
preferably from about 100 to over 1,000 capillary tubes, for
example, from about 500 to about 1,500. Preferably, the tubes are
arranged in rows and preferably the rows are arranged in columns.
Although in the embodiment shown in FIGS. 8 and 9 the bundle of
capillary tubes 72 has a circular cross-section and the band 74 is
ring shaped, other shapes of the bundle and band are also within
the scope of the present invention. For example, a rectangular or
square array of capillary tubes can be provided and surrounded by a
band, and the band would also preferably be of rectangular or
square shape. With rectangular or square-shaped arrays of capillary
tubes, distinct columns and rows of capillary tubes can be easily
identified, facilitating the identification of a single capillary
tube within the array.
In embodiments such as the one shown in FIGS. 8 and 9, the band 74
surrounding the bundle of capillary tubes has a length between
opposing surfaces 76 and 78 that is greater than the length between
the opposing ends 80 and 82 of the capillary tubes. As a result,
the banded assembly can be placed on a surface of, for example, an
analytical device, without the ends of the capillary tubes touching
the surface. In addition, the assemblies can be stacked without
disturbing the capillary holding forces in the through holes.
The assembly shown in FIGS. 8 and 9, as with the plates of FIGS.
1-7, can be loaded or filled with a starting liquid sample to
provide a plurality of samples, each constituting a portion of the
starting liquid sample. Alternatively, the assembly can be loaded
with more than one starting liquid sample, with each starting
liquid sample filling at least one of the through holes. Herein, by
"loaded" or "filled", what is meant is at least partially filled,
but not necessarily fully filled. The through-holes can be loaded
or filled, for example, by immersing the assembly or plate in a
liquid sample, contacting at least one of the opposing surfaces of
the assembly or plate with a liquid sample, or contacting the inner
walls of the respective through holes with a liquid sample or with
respective liquid samples.
Contact between a liquid sample and an opposing surface can be made
by flooding, immersing, pipetting, dropping, pouring, or otherwise
loading or at least partially filling a plurality of the capillary
tubes or through holes such that capillary action pulls portions of
the liquid sample into the respective capillary tubes or through
holes. Upon removal or discontinued contact of the liquid sample
with the assembly or plate, the opposing surfaces of the assembly
or plate are preferably made free of liquid sample such that the
portions of the sample that remain held within the respective
capillary tubes are isolated from one another.
Automated filling devices can be used and are preferred if it is
important that the respective liquid samples or liquid sample
portions are to only contact the inner walls of the through holes
and avoid contacting the opposing surfaces of the assembly.
According to embodiments of the present invention, a high
throughput screening method is provided. The method can screen for
at least one liquid sample that includes a target component or
substance to be analyzed. Herein, the target component or substance
to be analyzed may be referred to as an "analyte". The analyte may
be, but is not necessarily, a biological sample. The analyte
exhibits a detectable property or produces a detectable
characteristic in the presence of or upon reaction with a marker
compound or the like. For example, the analyte may itself exhibit a
fluorescent property. After the liquid sample is at least partially
filled into a plurality of the through holes, the portions of the
liquid sample that contain the analyte can be detected by
determining which of the through holes contains a sample portion
that exhibits the fluorescent property.
In another example, the analyte itself does not exhibit a
detectable property but may instead cause a marker component to
exhibit a detectable property upon reaction with the marker
component. According to such an embodiment, the through holes of
the testing assembly can be pre-loaded or post-loaded with one or
more marker components such that after loading the liquid sample
into the plurality of through holes, the sample portions containing
an analyte can react with the marker compound and thus enable the
marker compound to exhibit a detectable property. In such a case,
it is not the analyte itself that exhibits the detectable property,
but rather the analyte is detected indirectly as the presence of
the analyte causes the detectable property of the marker component
which in turn is directly detected. In so doing, the methods of the
present invention provide a way to partition and isolate analytes
from an original liquid sample.
According to the high throughput screening method, portions of the
liquid sample are loaded into a testing assembly having a pair of
opposing surfaces and a plurality of through holes, with each of
the through holes extending from one of the opposing surfaces to
the other of the opposing surfaces. Loading preferably results in
at least partially filling a plurality of the through holes with at
least portions of the liquid sample, and surface tension holds the
respective portions in the respective plurality of through holes.
Multiple liquid samples can instead be loaded into respective
through holes or into respective pluralities of through holes. The
method then involves detecting which of the plurality of sample
portions in the through holes exhibit the detectable property.
According to embodiments of the present invention, the high
throughput screening assembly preferably comprises at least about
100 through holes, more preferably at least about 500 through
holes, and according to some embodiments of the present invention,
up to about 1,000,000 through holes. High throughput screening
methods can be used in conjunction with these devices to test over
100,000,000 samples or sample portions per assembly per day.
The analyte to be screened may be, for example, a biological cell,
a mixture of biological cells, a mutant cell, a secretable protein,
an enzyme, a microorganism, a mixture of microorganisms, a
contaminant, or combinations thereof. The analyte can be a
population of random mutants of one or more organisms. If the
analyte is a mixture of biological cells it could be a random
sample isolated from a natural environment. The detectable property
may be, for example, a fluorescence or adsorption property. Prior
to filling the high throughput assembly, the liquid sample may be
diluted with a suitable diluent to obtain a concentration of the
analyte in the liquid sample such that when the sample is filled
into the plurality of through holes, at least one of the analytes
is introduced into from about one-quarter to about one-half of the
plurality of through holes.
In some cases, it is possible to identify an organism with
desirable properties even if the organism is introduced into a
plurality of through holes as a mixture with other organisms. Under
such conditions, the mixture of other organisms, e.g., mixture of
biological cells, may be diluted prior to filling such that several
organisms or cells will be introduced into each through hole. Using
such a dilution technique, it is possible to detect the presence of
an analyte. For example, it is possible to detect one particular
mutant from a collection of many biological cells and mutants
thereof despite having many cells from the mixture present in each
through hole. Thus, for example, if a sample contains 1,000,000
cells and only one of them is a target mutant cell, referred to as
the "analyte", and a testing plate having 10,000 through holes is
employed, the sample can be diluted such that the 1,000,000 cells
fill the through holes with sample portions wherein each portion
contains about 100 cells. In cases where the detectable
characteristic of the analyte is detectable despite the presence of
many other cells within the same through hole, it is possible to
isolate the analyte from 99.99% of the sample in a single
assay.
The testing plates used in accordance with the present invention,
including the plates of FIGS. 1-7 and the assemblies of FIGS. 8 and
9, can comprise hydrophilic materials or coatings, hydrophobic
materials or coatings, or a combination thereof to facilitate
loading of liquid sample portions into the through holes. For
example, the opposing surfaces of the assembly can be made of, or
treated with, a hydrophobic material such that liquid samples tend
to be repelled from the surface except in areas immediately
adjacent the through hole openings on the opposing surface.
According to such an embodiment, liquid sample portions can be
drawn into the through holes by capillary action without
wetting-out onto the opposing surfaces of the plate. As a result,
once the plate is loaded with and separated from a liquid sample no
fluid communications are provided between individual through holes
and contamination of the partitioned sample portions is minimized.
According to some embodiments of the present invention, the through
holes can include inner walls made of, or coated with, a
hydrophilic material that can be easily wetted by an aqueous sample
or medium. The entire inner walls of each through hole can be made
of or treated with a hydrophilic material or only portions of the
inner wall can be so made or treated. Plates having hydrophilic
inner walls for the through holes and hydrophobic opposing surfaces
provide excellent means to restrain, isolate, or limit the position
of liquid samples in the through holes of the testing plate while
keeping adjacent surface regions of the opposing surfaces
substantially free of liquid sample.
According to some embodiments of the present invention, to
facilitate the capillary reaction, it may be desirable to provide a
hydrophilic material immediately adjacent the opening to each
through hole on an opposing surface while maintaining or providing
the remaining area of the opposing surface hydrophobic or
non-hydrophilic. Either or both opposing surfaces of the testing
plate can be made of or treated with hydrophobic, hydrophilic, or
both materials as discussed above although if the through holes are
to be loaded by an immersion technique, it is preferred that the
opposing surface which will come in contact with the liquid sample
is treated with or formed of a hydrophobic material except in areas
immediately adjacent and preferably surrounding the through hole
openings in the opposing surface.
Exemplary high throughput screening methods that can be used with
the assemblies and other plates of the present invention include
absorbance transcription assays, fluorescent transcription assays,
fluorescent secreted enzyme assays, and microorganism screening
assays. These and other suitable assays that can benefit from the
plates and methods of the present invention are described, for
example, in: Arndt et al., A rapid genetic screening system for
identifying gene-specific suppression constructs for use in human
cells, Nucleic Acids Res., 28(6): E15 (2000); Rolls et al., A
visual screen of a GFP-fusion library identifies a new type of
nuclear envelope membrane protein, J. Cell Biol, 146(1): 29-44
(1999); Sieweke, Detection of transcription factor partners with a
yeast one hybrid screen, Methods Mol. Biol., 130: 59-77 (2000); and
WO 97/37036, all of which are herein incorporated in their
entireties by reference.
Having thus described the basic concept of the invention, it will
be rather apparent to those skilled in the art that the foregoing
detailed disclosure is intended to be presented by way of example
only, and is not limiting. Various alternations, improvements, and
modifications will occur and are intended to those skilled in the
art, though not expressly stated herein. These alterations,
improvements, and modifications are intended to be suggested
hereby, and are within the spirit and scope of the invention.
Accordingly, the invention is limited only by the following claims
and equivalents thereto.
* * * * *