U.S. patent application number 14/520510 was filed with the patent office on 2017-04-27 for exporting a selected group of micro-objects from a micro-fluidic device.
The applicant listed for this patent is Berkeley Lights, Inc.. Invention is credited to Keith J. Breinlinger, Daniele Malleo, Gaetan L. Mathieu, J. Tanner Nevill, Alexander H. Slocum, Mark P. White.
Application Number | 20170113231 14/520510 |
Document ID | / |
Family ID | 52993527 |
Filed Date | 2017-04-27 |
United States Patent
Application |
20170113231 |
Kind Code |
A9 |
Breinlinger; Keith J. ; et
al. |
April 27, 2017 |
EXPORTING A SELECTED GROUP OF MICRO-OBJECTS FROM A MICRO-FLUIDIC
DEVICE
Abstract
A group of micro-objects in a holding pen in a micro-fluidic
device can be selected and moved to a staging area, from which the
micro-objects can be exported from the micro-fluidic device. The
micro-fluidic device can have a plurality of holding pens, and each
holding pen can isolate micro-objects located in the holding pen
from micro-objects located in the other holding pens or elsewhere
in the micro-fluidic device. The selected group of micro-objects
can comprise one or more biological cells, such as a clonal
population of cells. Embodiments of the invention can thus select a
particular group of clonal cells in a micro-fluidic device, move
the clonal cells to a staging area, and export the clonal cells
from the micro-fluidic device while maintaining the clonal nature
of the exported group.
Inventors: |
Breinlinger; Keith J.; (San
Ramon, CA) ; Malleo; Daniele; (El Cerrito, CA)
; Mathieu; Gaetan L.; (Varennes, CA) ; Nevill; J.
Tanner; (El Cerrito, CA) ; Slocum; Alexander H.;
(Bow, NH) ; White; Mark P.; (San Francisco,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Berkeley Lights, Inc. |
Emeryville |
CA |
US |
|
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20150151307 A1 |
June 4, 2015 |
|
|
Family ID: |
52993527 |
Appl. No.: |
14/520510 |
Filed: |
October 22, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61996962 |
Oct 22, 2013 |
|
|
|
61996969 |
Oct 22, 2013 |
|
|
|
62058658 |
Oct 1, 2014 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01L 2300/087 20130101;
B01L 2400/086 20130101; G01N 27/44756 20130101; B01L 2200/027
20130101; B01L 2300/0829 20130101; B01L 2300/0816 20130101; B01L
2300/0819 20130101; B03C 2201/26 20130101; C12M 41/46 20130101;
B01L 2300/0645 20130101; B01L 2300/0636 20130101; B03C 5/026
20130101; G01N 33/5023 20130101; B01L 2300/0877 20130101; B01L
2400/0433 20130101; B01L 2400/0424 20130101; B01L 2200/0668
20130101; B01L 2400/0454 20130101; G01N 33/543 20130101; B01L
2200/0652 20130101; B01L 3/502761 20130101; C12M 47/02 20130101;
G01N 35/10 20130101; B01L 2300/0864 20130101; B01L 2300/044
20130101; G01N 33/54326 20130101; G01N 27/447 20130101; B03C 5/005
20130101; B01L 2300/0851 20130101; B81B 7/02 20130101; B03C 7/023
20130101; G01N 27/44791 20130101; C12M 23/16 20130101 |
International
Class: |
B03C 7/02 20060101
B03C007/02; B81B 7/02 20060101 B81B007/02 |
Claims
1. A process of exporting micro-objects from a micro-fluidic device
having an enclosure which comprises a plurality of holding pens,
said processing comprising: selecting a group of micro-objects
located in a holding pen that is one of said plurality of holding
pens inside said enclosure of said micro-fluidic device; moving
said selected group of micro-objects to a staging area inside said
enclosure; and exporting ones of said micro-objects of said
selected group from said staging area through a passage in said
enclosure to a location outside of said enclosure.
2. The process of claim 1, wherein said moving comprises isolating
said group of micro-objects from all other micro-objects disposed
in said micro-fluidic device.
3. The process of claim 1, wherein each holding pen of said
plurality comprises an isolation region configured to hold a
plurality of micro-objects.
4. The process of claim 1, wherein each micro-object of said
selected group is a biological cell.
5. The process of claim 4, wherein said selected group is a single
biological cell.
6. The process of claim 4, wherein said selected group is a clonal
population of biological cells.
7. The process of claim 1, wherein: said selecting comprises
determining that said group of micro-objects has a particular
activity or physical characteristic.
8. The process of claim 1, wherein: said selecting comprises
directing a pattern of light into said micro-fluidic device,
wherein said pattern of light surrounds said micro-objects of said
selected group and activates DEP forces that trap said
micro-objects of said selected group; and said moving comprises
moving said pattern of light to said staging area, wherein said
micro-objects of said selected group remain trapped by said DEP
forces activated by said pattern of light as said pattern of light
moves to said staging area.
9. The process of claim 1, wherein said staging area is located in
a channel defined by said enclosure of said micro-fluidic
device.
10. The process of claim 1, wherein said staging area is located
within said holding pen.
11. The process of claim 10, wherein moving said selected group of
micro-objects to said staging area comprises allowing gravity to
attract said group of micro-objects to said staging area.
12. The process of claim 1, wherein said exporting comprises
drawing said micro-objects of said selected group from said staging
area through said passage in said enclosure by drawing said
micro-objects of said selected group through an opening in a
proximal end of an export device.
13. The process of claim 12, wherein said drawing comprises
generating a pressure differential that draws said micro-objects of
said group into said opening at said proximal end of said export
device.
14. The process of claim 12, wherein said exporting further
comprises inserting said export device into an export interface
disposed over said passage in said enclosure, to thereby place said
opening at said proximal end of said export device adjacent to said
passage.
15. The process of claim 14, wherein: said export interface
comprises a self-closing cover disposed over and covering said
passage; and said inserting comprises opening said cover by
pressing said proximal end of said export device against a
separation in said cover and moving said proximal end of said
export device to be adjacent said passage.
16. The process of claim 14, wherein: said export interface
comprises a self-healing cover disposed over and covering said
passage; and said inserting comprises piercing said cover with said
proximal end of said export device and positioning said proximal
end of said export device adjacent to said passage.
17. The process of claim 1, wherein said selected group of
micro-objects is exported in a medium or other solution having a
volume of 1 .mu.L or less.
18. The process of claim 12 further comprising, after said
exporting, inspecting said export device for any un-exported
micro-objects of said selected group.
19. The process of claim 18 further comprising removing any
un-exported ones of said micro-objects from said export device.
20. The process of claim 1, wherein: said passage in said enclosure
is a second passage in said enclosure and is disposed adjacent a
second end of said staging area, said moving comprises moving said
selected group to a middle portion of said staging area between
said second end and an opposite first end of said staging area, and
said exporting comprises: flowing a liquid from a first export
device through a first passage in said enclosure toward said first
end of said staging area and thereby generating a flow from said
first end of said staging area to said second end of said staging
area, and drawing said micro-objects of said selected group from
said second end of said staging area through said second passage in
said enclosure into an opening at a proximal end of a second export
device disposed adjacent said second passage.
21. A micro-fluidic apparatus comprising: an enclosure configured
to contain a liquid medium, said enclosure comprising a passage
through said enclosure; a channel disposed inside said enclosure,
said channel having a plurality of holding pens which open off of
said channel, each holding pen of said plurality configured to hold
a group of micro-objects and isolate the group of micro-objects
from micro-objects in others of said plurality of holding pens; and
an export interface disposed on said enclosure adjacent said
passage, said export interface configured to interface an export
device such that an opening in a first end of said export device is
positioned adjacent to said passage through said enclosure.
22. The apparatus of claim 21, wherein said enclosure comprises at
least one staging area.
23. The apparatus of claim 22, wherein said at least one staging
area is located adjacent to said passage through said
enclosure.
24. The apparatus of claim 22, wherein said at least one staging
area is located in said channel.
25. The apparatus of claim 22, wherein said enclosure comprises a
plurality of staging areas, and wherein each holding pen comprises
one staging area of said plurality of staging areas.
26. The apparatus of claim 21, wherein said export interface
comprises a cover that covers entirely said passage through said
enclosure.
27. The apparatus of claim 26, wherein: said cover comprises a
separation dividing said cover into contiguous flaps, said flaps
are biased to contact one another to thereby cover entirely said
passage through said enclosure, and said flaps are sufficiently
flexible to move apart to form an opening to receive said first end
of said export device in response to a force of said first end of
said export device being pressed against said separation.
28. The apparatus of claim 26, wherein said cover comprises a
self-healing material that can be pierced by and thus form a hole
for receiving said export device but self-heals and thereby closes
said hole when said export device is removed from said
material.
29. The apparatus of claim 21 further comprising means for trapping
a group of said micro-objects in any one of said plurality of
holding pens and moving said trapped group of micro-objects to said
at least one staging area.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a non-provisional of (and thus claims
the benefit of and/or priority to) U.S. converted provisional
patent application Ser. No. 14/060,237. (The foregoing application
Ser. No. 14/060,237 was filed on Oct. 22, 2013 as a regular patent
application, then converted to a provisional patent application in
response to a Petition filed Oct. 17, 2014, which was granted Oct.
______, 2014.) This application also claims the benefit of and/or
priority to U.S. converted provisional patent application Ser. No.
14/060,321 and U.S. provisional patent application Ser. No.
62/058,658, filed Oct. 1, 2014. (The foregoing application Ser. No.
14/060,321 was filed on Oct. 22, 2013 as a regular patent
application but converted to a provisional patent application in
response to a Petition filed Oct. 7, 2014, which was granted Oct.
9, 2014.)
BACKGROUND
[0002] In biosciences and related fields, it can be useful to
export selected elements from a micro-fluidic device. Some
embodiments of the present invention include apparatuses and
processes for selecting a group of micro-objects in a particular
holding pen in a micro-fluidic device and exporting the selected
group from the micro-fluidic device.
SUMMARY
[0003] In some embodiments, the invention provides a process of
exporting micro-objects from a micro-fluidic device. The process
can include selecting a group of micro-objects located in a holding
pen located inside an enclosure of the micro-fluidic device. The
holding pen can be one of a plurality of holding pens located
inside the enclosure. The process can further include moving the
selected group of micro-objects to a staging area inside the
enclosure, and exporting the selected group of micro-objects from
said staging area, through a passage in the enclosure, to a
location outside of said enclosure. In certain embodiments, each
holding pen in the enclosure includes an isolation region
configured to hold a plurality of micro-objects. In certain
embodiments, moving the group of micro-objects includes isolating
the group of micro-objects from all other micro-objects disposed
within the micro-fluidic device.
[0004] In certain embodiments, one or more (or all) of the
micro-object in the selected group is a biological cell. In certain
embodiments, the selected group of micro-objects is a single
biological cell, such as an immunological cell, a cancer cell, a
transformed cell, a stem cell, or the like. In other embodiments,
the selected group of micro-objects is a plurality of cells, such
as a clonal population of biological cells.
[0005] In certain embodiments, selecting the group of micro-objects
includes determining that said group of micro-objects has a
particular activity or physical characteristic.
[0006] In certain embodiments, selecting the group of micro-objects
includes directing a pattern of light into the micro-fluidic device
such that the pattern of light surrounds the micro-objects of the
selected group and activates DEP forces that trap the micro-objects
of the selected group. In certain related embodiments, moving the
selected group of micro-objects includes moving the pattern of
light that surrounds the group to the staging area such that, as
the pattern of light moves to the staging area, the micro-objects
of the selected group remain trapped by the DEP forces activated by
the pattern of light.
[0007] In certain embodiments, the staging area is located in a
channel defined by the enclosure of the micro-fluidic device. For
example, the staging area can be adjacent to an opening from the
holding pen that contains the selected group of micro-objects into
the channel. In other embodiments, the staging area is located
within the holding pen that contains the selected group of
micro-objects. In certain related embodiments, moving the selected
group of micro-objects to the staging area includes allowing
gravity to attract the group of micro-objects to the staging
area.
[0008] In certain embodiments, exporting the selected group of
micro-objects includes drawing the micro-objects of the selected
group from the staging area, through the passage in the enclosure.
In certain embodiments, an export device is used to draw the
micro-objects of the selected group through a proximal end of the
export device and thereby through the passage in the enclosure. In
certain embodiments, drawing the micro-objects of the selected
group through the passage in the enclosure includes generating a
pressure differential that draws the micro-objects of the group
into the opening at the proximal end of the export device. In
certain embodiments, the export device is inserted into an export
interface disposed over the passage in the enclosure before the
selected group of micro-objects is exported. In certain
embodiments, inserting the export device into the export interface
places the opening at the proximal end of the export device
adjacent to the passage in the enclosure.
[0009] In certain embodiments, the micro-fluidic device includes an
export interface that has a self-closing cover disposed over and
covering the passage in the enclosure. In certain embodiments, an
export device can be inserted into such an export interface by
pressing the proximal end of the export device against a separation
in the self-closing cover and moving the proximal end of the export
device to a position adjacent to the passage in the enclosure.
[0010] In certain embodiments, the micro-fluidic device includes an
export interface that has a self-healing cover disposed over and
covering the passage in the enclosure. In certain embodiments, an
export device can be inserted into such an export interface by
piercing the self-healing cover with the proximal end of the export
device and positioning the proximal end of the export device
adjacent to the passage in the enclosure.
[0011] In certain embodiments, the selected group of micro-objects
is exported in a medium or other solution having a volume of 1
.mu.L or less. In other embodiments, the selected group of
micro-objects is exported in a medium or other solution having a
volume of 5 .mu.L, 10 .mu.L, 25 .mu.L, 50 .mu.L, or more.
[0012] In certain embodiments, after the selected group of
micro-objects is exported from the micro-fluidic device, the
staging area, the export interface, the export device, or any
combination thereof is inspected for micro-objects of the selected
group that failed to get exported. In certain embodiments,
micro-objects that failed to get exported are removed the staging
area, the export interface, and/or the export device. The
micro-objects that failed to get exported can be removed, for
example, by flushing and/or neutralizing the staging area, the
export interface, and/or the export device.
[0013] In certain embodiments, the enclosure of the micro-fluidic
device includes a first passage and a second passage. In certain
embodiments, the first passage is located adjacent to a first end
of the staging area and the second passage is located adjacent to a
second end of the staging area. In some embodiments, the staging
area has an elongated shape. In certain related embodiments, moving
the selected group of micro-objects includes moving the group to a
position in the staging area that is located at the first end, at
the second end, or between the first end and the second end of the
staging area. In certain related embodiments, exporting the
selected group of micro-objects includes flowing a liquid from a
first export device through the first passage in the enclosure
toward the first end of the staging area, and thereby generating a
flow from the first end of the staging area to the second end of
the staging area. In other related embodiments, exporting the
selected group of micro-objects includes drawing the micro-objects
of the selected group from the second end of the staging area
through the second passage in the enclosure, into an opening at a
proximal end of a second export device located adjacent to the
second passage.
[0014] In some embodiments, a process of exporting micro-objects
from a micro-fluidic device can include creating a flow of liquid
medium in an enclosure of the micro-fluidic device directly to an
outlet from the enclosure for the medium. In certain embodiments,
the flow of liquid medium is in a channel located within the
enclosure. The process can also include selecting a group of
micro-objects in a holding pen inside the enclosure, and moving the
selected group from the holding pen into the flow path of the
liquid medium. In certain embodiments, the flow of liquid medium is
maintained sufficiently for the flow to sweep the selected group to
the outlet and out of the enclosure through the outlet. In certain
embodiments, the flow of liquid medium is slowed or stopped while
the selected group is moved from the holding pen into the flow
path.
[0015] In some embodiments, the invention provides a micro-fluidic
apparatus. The micro-fluidic apparatus can include an enclosure
configured to contain a liquid medium and a passage through the
enclosure. The micro-fluidic apparatus can further include a
channel disposed inside the enclosure and at least one holding pen
which opens off of the channel. In certain embodiments, the
micro-fluidic device includes a plurality of holding pens which
open off of the channel. Each holding pen can be configured to hold
a group of micro-objects. In certain embodiments, each holding pen
is configured to isolate the group of micro-objects from
micro-objects in other holding pens in the micro-fluidic device. In
certain embodiments, each holding pend includes an isolation
region.
[0016] In certain embodiments, the micro-fluidic apparatus includes
an export interface. For example, the export interface can be
disposed on the enclosure adjacent to the passage through the
enclosure. In certain embodiments, the export interface comprises a
cover that covers entirely the passage through the enclosure. In
certain embodiments, the export interface is configured to
interface with an export device such that an opening in a first (or
proximal) end of the export device is located adjacent to the
passage through the enclosure.
[0017] In certain embodiments, the cover of the export interface
includes a separation that divides the cover into contiguous flaps.
In certain embodiments, the flaps are biased to contact one another
and thereby cover entirely the passage through the enclosure. In
certain embodiments, the flaps of the cover are sufficiently
flexible to move apart and form an opening the can receive the
first end of the export device when the first end of the export
device is pressed against the separation that divides the cover
into contiguous flaps. In other embodiments, the cover of the
export interface includes a self-healing material that can be
pierced by an export device. In certain embodiments, such piercing
forms a hole for receiving said export device, but the hole can
self-heal and thereby close when the export device is removed from
the cover.
[0018] In certain embodiments, the enclosure of the micro-fluidic
device includes at least one staging area. In certain embodiments,
the at least one staging area is located adjacent to the passage
through said enclosure. In certain embodiments, the staging area is
located in the channel. In certain embodiments, the enclosure
comprises a plurality of staging areas. In certain embodiments,
each holding pen in the micro-fluidic device includes a staging
area.
[0019] In some embodiments, the invention provides a system. The
system can include an micro-fluidic device and a means for trapping
and moving a group of micro-objects located within the
micro-fluidic device. The micro-fluidic device can be any device
described herein. In certain embodiments, the means for trapping
and moving the group of micro-objects is suitable for trapping a
group of micro-objects located in a holding pen within the
micro-fluidic device and moving the trapped group of micro-objects
to a staging area.
[0020] These and other aspects and advantages of the methods,
systems, and devices of the invention will be set forth or will
become more fully apparent in the description that follows and in
the appended claims. The features and advantages may be realized
and obtained by means of the instruments and combinations
particularly pointed out in the appended Examples and claims.
Furthermore, the aspects and advantages of the described systems,
devices, and methods may be learned by the practice or will be
obvious from the description, as set forth hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1A is a perspective view of a micro-fluidic device.
[0022] FIG. 1B is a top, cross-sectional view of the micro-fluidic
device of FIG. 1A.
[0023] FIG. 1C is a side, cross-sectional view of the micro-fluidic
device of FIG. 1A.
[0024] FIG. 1D is a partial, side, cross-sectional view of the
micro-fluidic device of FIG. 1A illustrating insertion of an export
device into an export interface.
[0025] FIG. 2A is a partial side, cross-sectional view of the
micro-fluidic device of FIGS. 1A-1C absent the holding pens (for
ease of illustration) in which the selector is configured as a
dielectrophoresis (DEP) device.
[0026] FIG. 2B is a partial top, cross-section view of FIG. 2A.
[0027] FIG. 3 is an example of a process for exporting a group of
micro-objects from a micro-fluidic device.
[0028] FIG. 4 shows an example of groups of micro-objects in
holding pens in the micro-fluidic device of FIGS. 1A-1C.
[0029] FIG. 5 illustrates an example of selecting and trapping a
group of micro-objects in one of the holding pens.
[0030] FIG. 6 shows an example of moving the trapped group of
micro-objects from the holding pen toward a staging area in the
micro-fluidic device.
[0031] FIG. 7 shows the group of micro-objects in the staging
area.
[0032] FIG. 8 illustrates an example of an export device inserted
into an export interface of the micro-fluidic device of FIGS.
1A-1C.
[0033] FIG. 9 shows an example of the micro-objects being drawn
from the staging area into the export device.
[0034] FIG. 10 illustrates an example of a process for exporting a
group of micro-objects from the staging area.
[0035] FIG. 11 is an example process for neutralizing the staging
area and export interface of un-exported micro-objects.
[0036] FIG. 12A is a partial, perspective view of the micro-fluidic
device of FIGS. 1A-1C with an embodiment of the export interface
that includes a self-closing cover.
[0037] FIG. 12B is a partial, side cross-sectional view of FIG.
12A.
[0038] FIG. 12C shows an export device inserted into the export
interface of FIGS. 12A and 12B.
[0039] FIG. 13A is a partial, side cross-sectional view of the
micro-fluidic device of FIGS. 1A-1C with an embodiment of the
export interface that includes a self-healing cover.
[0040] FIG. 13B illustrates an export device in the form of a
hypodermic needle inserted into the export interface of FIG.
13A.
[0041] FIG. 13C shows a hypodermic needle inserted into a different
part of the export interface of FIG. 13A.
[0042] FIG. 14 is a partial, side cross-sectional view of the
micro-fluidic device of FIGS. 1A-1C with an embodiment of the
export interface that includes an attached tubular export
device.
[0043] FIG. 15A is a partial, perspective view of a micro-fluidic
device that includes a plurality of export interfaces.
[0044] FIG. 15B is top, cross-sectional view of FIG. 15A
illustrating a staging area that comprises a middle portion between
opposite ends.
[0045] FIG. 15C is a side, cross-sectional view of FIG. 15A.
[0046] FIG. 16 is a side, cross-sectional view of the micro-fluidic
device of FIG. 15A illustrating export devices inserted into the
export interfaces.
[0047] FIG. 17 is a top, cross-sectional view of a micro-fluidic
device comprising holding pens and multiple staging areas in a flow
path in the device.
[0048] FIG. 18 is a top, cross-sectional view of a micro-fluidic
device comprising holding pens and a staging area, with the holding
pens opening from a channel that is separated by a continuous
barrier from the flow path in which the staging area is
located.
[0049] FIG. 19A is a top, cross-sectional view of a micro-fluidic
device comprising holding pens with staging areas located in a
channel from which the holding pens open, adjacent the opening to
each holding.
[0050] FIG. 19B is a side, cross-sectional view of the microfluidic
device of FIG. 19A.
[0051] FIG. 20 illustrates an example of a process for exporting
micro-objects from the device of FIGS. 19A-19B.
[0052] FIG. 21A is a partial, side, cross-sectional view of a
micro-fluidic device in which export interfaces can be located
directly adjacent holding pens.
[0053] FIG. 21B is a partial, top, cross-sectional view of a
micro-fluidic device in which the holding pen includes an isolation
region, a portion of which is a staging area.
[0054] FIG. 21C is a partial, top, cross-sectional view of a
holding pen in a microfluidic device in which the holding pen
includes an isolation region and a connected staging area.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0055] This specification describes exemplary embodiments and
applications of the invention. The invention, however, is not
limited to these exemplary embodiments and applications or to the
manner in which the exemplary embodiments and applications operate
or are described herein. Moreover, the figures may show simplified
or partial views, and the dimensions of elements in the figures may
be exaggerated or otherwise not in proportion for clarity. In
addition, as the terms "on," "attached to," or "coupled to" are
used herein, one element (e.g., a material, a layer, a substrate,
etc.) can be "on," "attached to," or "coupled to" another element
regardless of whether the one element is directly on, attached, or
coupled to the other element or there are one or more intervening
elements between the one element and the other element. Also,
directions (e.g., above, below, top, bottom, side, up, down, under,
over, upper, lower, horizontal, vertical, "x," "y," "z," etc.), if
provided, are relative and provided solely by way of example and
for ease of illustration and discussion and not by way of
limitation. In addition, where reference is made to a list of
elements (e.g., elements a, b, c), such reference is intended to
include any one of the listed elements by itself, any combination
of less than all of the listed elements, and/or a combination of
all of the listed elements.
[0056] As used herein, "substantially" means sufficient to work for
the intended purpose. The term "substantially" thus allows for
minor, insignificant variations from an absolute or perfect state,
dimension, measurement, result, or the like such as would be
expected by a person of ordinary skill in the field but that do not
appreciably affect overall performance. The term "ones" means more
than one.
[0057] The term "aspirate" as used with respect to a micro-object
means to move the micro-object utilizing a pressure differential,
and an "aspirator" is a pressure differential generating
device.
[0058] As used herein, the term "micro-object" can encompass one or
more of the following: inanimate micro-objects such as
microparticles, microbeads (e.g., polystyrene beads, Luminex.TM.
beads, or the like), magnetic beads, microrods, microwires, quantum
dots, and the like; biological micro-objects such as cells (e.g.,
embryos, oocytes, sperms, cells dissociated from a tissue, blood
cells, hydridomas, cultured cells, cells from a cell line, cancer
cells, infected cells, transfected and/or transformed cells,
reporter cells, and the like), liposomes (e.g, synthetic or derived
from membrane preparations), lipid nanorafts, and the like; or a
combination of inanimate micro-objects and biological micro-objects
(e.g., microbeads attached to cells, liposome-coated micro-beads,
liposome-coated magnetic beads, or the like). Lipid nanorafts have
been described, e.g., in Ritchie et al. (2009) "Reconstitution of
Membrane Proteins in Phospholipid Bilayer Nanodiscs," Methods
Enzymol., 464:211-231.
[0059] The term "flow," as used herein with reference to a liquid,
refers to bulk movement of the liquid primarily due to any
mechanism other than diffusion. For example, flow of a medium can
involve movement of the fluidic medium from one point to another
point due to a pressure differential between the points. Such flow
can include a continuous, pulsed, periodic, random, intermittent,
or reciprocating flow of the liquid, or any combination thereof.
When one fluidic medium flows into another fluidic medium,
turbulence and mixing of the media can result.
[0060] The phrase "substantially no flow" refers to a rate of flow
of a liquid that is less than the rate of diffusion of components
of a material (e.g., an analyte of interest) into or within the
liquid. The rate of diffusion of components of such a material can
depend on, for example, temperature, the size of the components,
and the strength of interactions between the components and the
fluidic medium.
[0061] As used herein in reference to a fluidic medium, "diffuse"
and "diffusion" refer to thermodynamic movement of a component of
the fluidic medium down a concentration gradient.
[0062] As used herein in reference to different regions within a
microfluidic device, the phrase "fluidically connected" means that,
when the different regions are substantially filled with fluid,
such as fluidic media, the fluid in each of the regions is
connected so as to form a single body of fluid. This does not mean
that the fluids (or fluidic media) in the different regions are
necessarily identical in composition. Rather, the fluids in
different fluidically connected regions of a microfluidic device
can have different compositions (e.g., different concentrations of
solutes, such as proteins, carbohydrates, ions, or other molecules)
which are in flux as solutes move down their respective
concentration gradients and/or fluids flow through the device.
[0063] A microfluidic device or apparatus of the invention can
comprise "swept" regions and "unswept" regions. An unswept region
can be fluidically connected to a swept region, provided the
fluidic connections are structured to enable diffusion but
substantially no flow of media between the swept region and the
unswept region. The microfluidic apparatus can thus be structured
to substantially isolate an unswept region from a flow of medium in
a swept region, while enabling substantially only diffusive fluidic
communication between the swept region and the unswept region.
[0064] "Sterilizing" a biological cell means rendering the cell
unable to reproduce.
[0065] As used herein, a "group" of micro-objects can be a single
micro-object or a plurality of micro-objects. The group of
micro-objects can be a clonal group of biological cells (e.g., one
cell, a plurality of cells, or all of the cells from a clonal
colony). A colony of biological cells is "clonal" if all of the
living cells in the colony that are capable of reproducing are
daughter cells derived from a single parent cell. "Clonal cells"
are cells of the same clonal colony.
[0066] In some embodiments of the invention, a group of
micro-objects can be captured from a selected holding pen in a
micro-fluidic device and moved from the holding pen to a staging
area, where the micro-objects of the group can be exported from the
micro-fluidic device. The micro-objects can be biological cells.
Each holding pen can isolate biological cells in the holding pen
from biological cells in others of the holding pens (e.g., by
having the biological cells located in an isolation region of the
holding pen). The micro-objects captured from the selected holding
pen can be clonal cells, and embodiments of the invention can
select a particular group of clonal cells in a micro-fluidic
device, move the clonal cells to a staging area, and export the
clonal cells from the micro-fluidic device while maintaining the
clonal nature of the group.
[0067] FIGS. 1A-1D illustrate an example of a micro-fluidic device
100 comprising holding pens 156, a selector 122, and an export
interface 162. As will be seen, the selector 122 can select and
move micro-objects (not shown) from any of the pens 156 to a
staging area 172 inside an enclosure 102 of the device 100, and the
export interface 162 provides an interface into the enclosure 102
for an external export device 182 that can export the micro-objects
(not shown) from the staging area 172.
[0068] As shown in FIGS. 1A-1D, the micro-fluidic device 100 can
comprise an enclosure 102, a selector 122, a flow controller 124,
and an export interface 162 for an external export device 182. As
also shown, the micro-fluidic device 100 can include auxiliary
elements such as a control module 130, a source of electromagnet
radiation 136 (hereinafter an EM source 136), a detector 138,
and/or the like.
[0069] The enclosure 102 can define a flow region 140 and hold a
liquid medium 144. The enclosure 102 can comprise, for example, a
micro-fluidic structure 104 disposed on a base (e.g., a substrate)
106. The micro-fluidic structure 104 can comprise a flexible
material, such as rubber, plastic, an elastomer, silicone (e.g.,
patternable silicone), polydimethylsiloxane ("PDMS"), or the like,
which can be gas permeable. Other examples of materials that can
compose microfluidic structure 104 include molded glass, an
etchable material such as silicon, photo-resist (e.g., SU8), or the
like. In some embodiments, such materials--and thus the
microfluidic structure 104--can be rigid and/or substantially
impermeable to gas. Regardless, the microfluidic structure 104 can
be disposed on the base 106. The base 106 can comprise one or more
substrates. Although illustrated as a single structure, the base
106 can comprise multiple interconnected structures such as
multiple substrates. The micro-fluidic structure 104 can likewise
comprise multiple structures, which can be interconnected. For
example, the micro-fluidic structure 104 can additionally comprise
a cover (not shown) made from material that is the same as or
different than the other material in the structure.
[0070] The micro-fluidic structure 104 and the base 106 can define
a micro-fluidic flow region 140. Although one flow region 140 is
shown in FIGS. 1A-1C, the micro-fluidic structure 104 and the base
106 can define multiple flow regions for the medium 144. The flow
region 140 can comprise channels (152, 153 in FIG. 1B) and
chambers, which can be interconnected to form micro-fluidic
circuits. FIGS. 1B and 1C illustrate an inner surface 142 of the
flow region 140 on which the medium 144 can be disposed as even
(e.g., flat) and featureless. The inner surface 142, however, can
alternatively be uneven (e.g., not flat) and comprise features such
as electric terminals (not shown).
[0071] As shown, the enclosure 102 can comprise one or more inlets
108 through which medium 144 can be input into the flow region 140.
An inlet 108 can be, for example, an input port, an opening, a
valve, another channel, fluidic connectors, a tube, a fluid pump
(e.g., a positive displacement syringe pump), or the like. The
enclosure 102 can also comprise one or more outlets 110 through
which the medium 144 can be removed from the flow region 140. An
outlet 110 can be, for example, an output port, an opening, a
valve, a channel, fluidic connectors, a tube, a pump, or the like.
As another example, the outlet 110 can comprise a droplet
outputting mechanism such as any of the outputting mechanisms
disclosed in U.S. patent application Ser. No. 13/856,781 filed Apr.
4, 2013 (attorney docket no. BL1-US). All or part of the enclosure
102 can be gas permeable to allow gas (e.g., ambient air) to enter
and exit the flow region 140. For enclosures that comprise more
than one flow region 140, each flow region 140 can be associated
with one or more inlets 108 and one or more outlets 110 for
respectively inputting and removing medium 144 from the flow region
140.
[0072] As shown in FIGS. 1B and 1C, holding pens 156 can be
disposed in the flow region 140. For example, each holding pen 156
can comprise a barrier 154 disposed on an interior surface 142 of
the enclosure 102. There can be many such holding pens 156 in the
flow region 140 disposed in any pattern, and the holding pens 156
can be any of many different sizes and shapes. For example, the
holding pens 156 can comprise a structure as described in U.S.
Provisional Application 62/058,658, filed Oct. 1, 2014. Thus, for
example, the holding pens 156 can include a connection region (not
shown) and an isolation region (not shown). As shown in FIG. 1C,
openings of the holding pens 156 can be disposed adjacent a channel
152, 153, which can be a conduit for medium 144 flowing past the
openings of more than one pen 156. The opening of each holding pen
156 can allow for the natural exchange of liquid medium 144 flowing
in a channel 152, 153 but each holding pen 156 can otherwise be
sufficiently enclosed to prevent micro-objects (not shown), such as
biological cells, in any one pen 156 from mixing with micro-objects
in any other pen 156. Although eight pens 156 and two channels 152,
153 are shown, there can be more or fewer. For example, there can
be a single channel fluidically connected with 100, 250, 500, 1000,
2500, 5000, 10000, 25000, 50000, 100000, or more holding pens.
[0073] Medium 144 can be flowed in channels 152, 153 past openings
in the holding pens 156. The flow of medium 144 in channels 152,
153 can, for example, provide nutrients to biological micro-objects
(not shown) in the holding pens 156. The flow of medium 144 in
channels 152, 153 can also provide for the removal of waste from
the holding pens 156. For holding pens 156 that comprise an
isolation region, exchange of nutrients and waste between the
isolation regions and the channels 152, 153 can occur substantially
only by diffusion.
[0074] As also shown, there can be a staging area 172 in the flow
region 140 and thus inside the enclosure 102. The staging area 172
can be simply an area on an interior surface 142 of the enclosure
102, which can be marked or unmarked. Alternatively, the staging
area 172 can comprise a structure in the flow region 140 such as a
depression into the surface 142 (as shown in FIGS. 1B-1D), a
platform (not shown) extending out of the surface 142, barriers
(not shown) (e.g., similar to barriers 154), chambers, or the like.
Regardless, as shown in FIG. 1D, the staging area 172 can be
disposed adjacent to (e.g., across the flow region 140 from) a
passage 174 through the enclosure 102 and into the flow region 140.
The passage 174 can be from outside the enclosure 102 to inside the
enclosure 102. The passage 174 can be, for example, a hole in the
enclosure 102.
[0075] The export interface 162 can provide an interface to the
passage 174 into the enclosure 102 for an external export device
182, which can be a device that is external to the enclosure 102.
As shown in FIG. 1C, the export interface 162 can be disposed on
the enclosure 102 adjacent (e.g., over and/or within) the passage
174. The export interface 162 can comprise an opening 164 to the
passage 174. The export interface 162 can further comprise a cover
166 over the opening 164. The cover 166 can be removable or
otherwise breachable by the export device 182, which can be
inserted into the opening 164 in the export interface 162 to engage
the passage 174 into the enclosure 102. Although shown as distinct
entities, the export interface 162 and the micro-fluidic structure
104 can be integrally formed of the same material and thus be
portions of one physical entity.
[0076] The export interface 162 can comprise, for example, a
flexible material such as polystyrene or any of the materials
discussed above with respect to the micro-fluidic structure 104.
Alternatively, the export interface 162 can comprise a hard or
stiff material or a combination of flexible and hard or stiff
materials. Examples of the cover 166 include a cover that can be
attached to and detached from the enclosure 102, a cork like
structure (not shown) that can be inserted into the opening 164 but
is smaller than the passage 174, or the like. As will be seen in
FIGS. 12A-13B, other examples of the cover 166 include a
self-closing cover 1206 that can be pushed open by the export
device 182 and an export interface 1302 in the form of a
pierceable, self-healing structure.
[0077] As shown in FIG. 1D, the export device 182 can be a hollow
tube-like structure. For example, the export device 182 can
comprise a tubular housing 184 that defines an interior passage 186
from a first end 188 to an opposite second end 192. With the cover
166 of the export interface 162 removed, the export device 182 can
be inserted into the opening 164 in the interface 162 such that the
first end 188 is brought into proximity or contact with the
enclosure passage 174. An opening 190 at the first end 188 of the
export device 182 can thus be placed adjacent to the passage 174
into the enclosure 102.
[0078] In some embodiments, the export device 182 can be a pressure
differential generating device (e.g., an aspirator, a positive
displacement syringe pump, an air displacement pump, a peristaltic
pump, or the like). For example, the export device 182 can be
connectable to a source capable of generating a pressure
differential (not shown), which can generate a pressure
differential from the first end 188 to the second end 192 of the
export device 182. The export device 182 can thus be configured to
draw micro-objects (not shown) from the staging area 172 through
the passage 174 into the opening 190 in its first end 188 through
the internal passage 186 to the second end 192, where the
micro-objects (not shown) can be collected or otherwise disposed
of. Examples of the export device 182 include a pipette, a tube, a
hollow needle such as a hypodermic needle, combination thereof or
the like. The internal passage 186 of the export device can have a
diameter of about 5 .mu.m to 300 .mu.m (e.g., about 25 to 300
.mu.m, about 50 to 300 .mu.m, about 75 to 300 .mu.m, about 100 to
300 .mu.m, about 100 to 250 .mu.m, about 100 to 200 .mu.m, about
100 to 150 .mu.m, about 150 to 200 .mu.m, or any other diameter or
range defined by one or more of the foregoing endpoints).
[0079] The export device 182 can further comprise a sensor (not
shown) capable of detecting micro-objects that pass through the
export device. The sensor can be located proximal to the export
interface 162. Alternatively, the sensor can be located distal to
the export interface 162 (e.g., at the distal end of the export
device 182). The sensor can be, for example, an imaging device,
such as a camera (e.g., a digital camera) or a photosensor (e.g., a
charge coupled device or a complementary metal-oxide semiconductor
imager). Alternatively, the sensor can be an electrical device,
such as a device that detects changes in complex impedance when
micro-objects pass by.
[0080] The selector 122 can be configured to create selectively
electrokinetic forces on micro-objects (not shown) in the medium
144. For example, the selector 122 can be configured to selectively
activate (e.g., turn on) and deactivate (e.g., turn off) electrodes
at the inner surface 142 of the flow region 140. The electrodes can
create forces in the medium 144 that attract or repel micro-objects
(not shown) in the medium 144, and the selector 122 can thus select
and move one or more micro-objects in the medium 144. The
electrodes can be, for example, dielectrophoresis (DEP)
electrodes.
[0081] For example, the selector 122 can comprise one or more
dieletrophoresis electrode devices, optical (e.g., laser) tweezers
devices, and/or one or more optoelectronic tweezers (OET) devices
(e.g., as disclosed in U.S. Pat. No. 7,612,355 (which is
incorporated in its entirety by reference herein) or U.S. patent
application Ser. No. 14/051,004 (attorney docket no. BL9-US) (which
is also incorporated in its entirety by reference herein). As yet
another example, the selector 122 can include one or more devices
(not shown) for moving a droplet of the medium 144 in which one or
more of micro-objects are suspended. Such devices (not shown) can
include electrowetting devices such as optoelectronic wetting (OEW)
devices (e.g., as disclosed in U.S. Pat. No. 6,958,132) or other
electrowetting devices. The selector 122 can thus be characterized
as a DEP device in some embodiments.
[0082] FIGS. 2A and 2B illustrate an example in which the selector
122 comprises a DEP device 200. As shown, the DEP device 200 can
comprise a first electrode 204, a second electrode 210, an
electrode activation substrate 208, a power source 212 (e.g., an
alternating current (AC) power source), and a light source 220
(which can be the same as or different than the EM source 136).
Medium 144 in the flow region 140 and the electrode activation
substrate 208 can separate the electrodes 204, 210. Changing
patterns of light 222 from the light source 220 can selectively
activate and deactivate changing patterns of DEP electrodes at
regions 214 of the inner surface 142 of the flow region 140.
(Hereinafter the regions 214 are referred to as "electrode
regions.")
[0083] In the example illustrated in FIG. 2B, a light pattern 222'
directed onto the inner surface 142 illuminates the cross-hatched
electrode regions 214a in the square pattern shown. The other
electrode regions 214 are not illuminated and are hereinafter
sometimes referred to as "dark" electrode regions 214. The relative
electrical impedance across the electrode activation substrate 208
from each dark electrode region 214 to the second electrode 210 is
greater than the relative impedance from the first electrode 204
across the medium 144 in the flow region 140 to the dark electrode
region 214. Illuminating an electrode region 214a, however, reduces
the relative impedance across the electrode activation substrate
208 from the illuminated electrode region 214a to the second
electrode 210 to less than the relative impedance from the first
electrode 204 across the medium 144 in the flow region 140 to the
illuminated electrode region 214a.
[0084] With the power source 212 activated, the foregoing creates
an electric field gradient in the medium 144 between illuminated
electrode regions 214a and adjacent dark electrode regions 214,
which in turn creates local DEP forces that attract or repel nearby
micro-objects (not shown) in the medium 144. DEP electrodes that
attract or repel micro-objects in the medium 144 can thus be
selectively activated and deactivated at many different such
electrode regions 214 at the inner surface 142 of the flow region
140 by changing light patterns 222 projected form a light source
220 (e.g., a laser source or other type of light source) into the
micro-fluidic device 100. Whether the DEP forces attract or repel
nearby micro-objects can depend on such parameters as the frequency
of the power source 212 and the dielectric properties of the medium
144 and/or micro-objects (not shown).
[0085] The square pattern 222' of illuminated electrode regions
214a illustrated in FIG. 2B is an example only. Any pattern of the
electrode regions 214 can be illuminated by the pattern of light
222 projected into the device 100, and the pattern of illuminated
electrode regions 222' can be repeatedly changed by changing the
light pattern 222.
[0086] In some embodiments, the electrode activation substrate 208
can be a photoconductive material, and the inner surface 142 can be
featureless. In such embodiments, the DEP electrodes 214 can be
created anywhere and in any pattern on the inner surface 142 of the
flow region 140 in accordance with the light pattern 222 (see FIG.
2A). The number and pattern of the electrode regions 214 are thus
not fixed but correspond to the light pattern 222. Examples are
illustrated in the aforementioned U.S. Pat. No. 7,612,355, in which
the un-doped amorphous silicon material 24 shown in the drawings of
the foregoing patent can be an example of photoconductive material
that can compose the electrode activation substrate 208.
[0087] In other embodiments, the electrode activation substrate 208
can comprise a circuit substrate such as a semiconductor material
comprising a plurality of doped layers, electrically insulating
layers, and electrically conductive layers that form semiconductor
integrated circuits such as is known in semiconductor fields. In
such embodiments, electric circuit elements can form electrical
connections between the electrode regions 214 at the inner surface
142 of the flow region 140 and the second electrode 210 that can be
selectively activated and deactivated by the light pattern 222.
When not activated, each electrical connection can have high
impedance such that the relative impedance from a corresponding
electrode region 214 to the second electrode 210 is greater than
the relative impedance from the first electrode 204 through the
medium 144 to the corresponding electrode region 214. When
activated by light in the light pattern 222, however, each
electrical connection can have low impedance such that the relative
impedance from a corresponding electrode region 214 to the second
electrode 210 is less than the relative impedance from the first
electrode 204 through the medium 144 to the corresponding electrode
region 214, which activates a DEP electrode at the corresponding
electrode region 214 as discussed above. DEP electrodes that
attract or repel micro-objects (not shown) in the medium 144 can
thus be selectively activated and deactivated at many different
electrode regions 214 at the inner surface 142 of the flow region
140 by the light pattern 222. Non-limiting examples of such
configurations of the electrode activation substrate 208 include
the phototransistor-based device illustrated in FIGS. 21 and 22 of
U.S. Pat. No. 7,956,339 and the devices 200, 400, 500, and 600
illustrated throughout the drawings in the aforementioned U.S.
patent application Ser. No. 14/051,004, filed Oct. 10, 2013.
[0088] In some embodiments, the first electrode 204 can be part of
a first wall 202 (or cover) of the enclosure 102, and the electrode
activation substrate 208 and second electrode 210 can be part of a
second wall 206 (or base) of the enclosure 102, generally as
illustrated in FIG. 2A. As shown, the flow region 140 can be
between the first wall 202 and the second wall 206. The foregoing,
however, is but an example. In other embodiments, the first
electrode 204 can be part of the second wall 206 and one or both of
the electrode activation substrate 208 and/or the second electrode
210 can be part of the first wall 202. As another example, the
first electrode 204 can be part of the same wall 202 or 206 as the
electrode activation substrate 208 and the second electrode 210.
For example, the electrode activation substrate 208 can comprise
the first electrode 204 and/or the second electrode 210. Moreover,
the light source 220 can alternatively be located below the
enclosure 102.
[0089] Configured as the DEP device 200 of FIGS. 2A and 2B, the
selector 122 can thus select a micro-object (not shown) in the
medium 144 in the flow region 140 by projecting a light pattern 222
into the device 100 to activate one or more DEP electrodes at
electrode regions 214 of the inner surface 142 of the flow region
140 in a pattern that surrounds and captures the micro-object. The
selector 122 can then move the captured micro-object by moving the
light pattern 222 relative to the device 100. Alternatively, the
device 200 can be moved relative to the light pattern 322.
[0090] Although the barriers 154 that define the holding pens 156
are illustrated in FIGS. 1B and 1C and discussed above as physical
barriers, the barriers 154 can alternatively be virtual barriers
comprising DEP forces activated by the light pattern 222.
[0091] The flow controller 124 can be configured to control a flow
of the medium 144 in the flow region 140. For example, the flow
controller 124 can control the direction and/or velocity of the
flow. Non-limiting examples of the flow controller 124 include one
or more pumps or fluid actuators. In some embodiments, the flow
controller 124 can include additional elements such as one or more
sensors (not shown) for sensing, for example, the velocity of the
flow of the medium 144 in the flow region 140.
[0092] The control module 130 can be configured to receive signals
from and control the selector 122, EM source 136, the detector 138,
and/or the flow controller 124. As shown, the control module 130
can comprise a controller 132 and a memory 134. In some
embodiments, the controller 132 can be a digital electronic
controller (e.g., a microprocessor, microcontroller, computer, or
the like) configured to operate in accordance with machine readable
instructions (e.g., software, firmware, microcode, or the like)
stored as non-transitory signals in the memory 134, which can be,
for example, a digital electronic, optical, or magnetic memory
device. Alternatively, the controller 132 can comprise hardwired
digital circuitry and/or analog circuitry or a combination of a
digital electronic controller operating in accordance with machine
readable instructions and hardwired digital circuitry and/or analog
circuitry. The control module 130 can be configured to perform all
or any part of any process, function, step, or the like disclosed
herein.
[0093] The EM source 136 can selectively direct electromagnetic
radiation into the enclosure 102. The electromagenetic radiation
can include a wavelength that is absorbed by and/or excites a
label, such as a chromophore (e.g., a fluorophorein). The
electromagenetic radiation can comprise a wavelength in the visible
or ultraviolet regions of the electromagnetic spectrum. The EM
source 136 can be, for example, a laser light source, a light
emitting diode (LED), a high intensity discharge lamp, or the like,
which can be controlled by the control module 130 to direct light
beams at specific target areas inside the flow region 140. The
detector 138 can be a mechanism for capturing images (e.g., digital
images) of the flow region 140 including, for example, the pens
156, micro-objects (not shown) in the medium 144, and the staging
area 172. The detector 138 can also capture images of the export
interface 162. Examples of suitable imaging devices that the
detector 138 can comprise include digital cameras or photosensors
such as charge coupled devices and complementary
metal-oxide-semiconductor imagers. Images can be captured with such
devices and analyzed (e.g., by the control module 130 and/or a
human operator).
[0094] In some embodiments, the pens 156 can be shielded from
illumination (e.g., by the selector 122, the EM source, and/or the
detector 138) or can be only selectively illuminated for brief
periods of time. Biological micro-objects 402 can thus be protected
from illumination or illumination of the biological micro-objects
402 can be minimized before the biological micro-objects 502 are
exported.
[0095] FIG. 3 illustrates an example process 300 for exporting a
group of micro-objects from a micro-fluidic device according to
some embodiments. The process 300 can be performed with the
micro-fluidic device 100 of FIGS. 1A-1D. The selector 122 can be
configured as a DEP device as shown in FIGS. 2A and 2B. The process
300 is not so limited, however, but can be performed with other
micro-fluidic devices.
[0096] At step 302, the process 300 can move a group of
micro-objects from a holding pen in the micro-fluidic device to a
staging area. The group can consist of a specific one or more of
the micro-objects in the holding pen. FIGS. 4-7 illustrate an
example.
[0097] As shown in FIG. 4, there can be groups 402 of micro-objects
in a plurality of the holding pens 156. For example, the
micro-objects can be biological cells, and each group 402 in one of
the holding pens 156 can be a clonal colony of cells. As also
shown, a flow 404 of the medium 144 can be provided, for example,
from the inlet 108 to the outlet 110.
[0098] As illustrated in FIG. 5, one of the groups 402 in one of
the holding pens 156 can be selected. A particular group 402 and/or
holding pen 156 can be identified, for example, from images of the
flow region 140 captured by the detector 138 (see FIG. 1A). The
selection can be based on the physical characteristics of or an
activity associated with the micro-objects in the holding pen 156.
Such physical characteristics can include, e.g., the number of
micro-objects, their size, their morphology, or the like. Activity
associated with the micro-objects can include, e.g., production or
presentation of an antigen of interest (such as an antibody,
cytokine, growth factor, metabolite, cancer cell marker, or the
like), rate of growth, or any combination thereof. In FIG. 5, the
selected group 402 is labeled 502. Although the selected group 502
is illustrated as including all of the micro-objects in a pen 156,
the selected group 502 can instead include less than all (e.g., 1,
2, 3, 4, 5, or so) of the micro-objects in the group 402 in the pen
156.
[0099] In the example shown in FIG. 5, the selected group 502 of
micro-objects is trapped with a light trap 504, which can be
generated by the selector 122 configured as the DEP device 200 of
FIGS. 2A and 2B. For example, the light trap 504 can comprise a
contiguous pattern of activated DEP electrodes 214 that enclose the
selected group 502. As discussed above, the DEP electrodes 214 can
be selectively activated by a pattern 222 of light directed onto
the electrode activation substrate 208 (see FIGS. 2A and 2B).
[0100] As shown in FIG. 6, the light trap 504 can be moved from the
holding pen 156 toward the staging area 172, which also moves the
selected group 502 of micro-objects. The light trap 504 can then be
moved into the staging area 172. As discussed above, the light trap
504 can be moved by changing the light pattern 222 directed onto
the electrode activation substrate 208. Images of the flow region
140 captured by the detector 138 can facilitate selecting,
trapping, and moving the group 502 to the staging area 172.
[0101] The light trap 504 can be configured to, for example, repel
the micro-objects in the medium 144. The light trap 504 can thus
keep the micro-objects of the selected group 502 inside the trap
504 and keep all other micro-objects from every other group 402
outside of the trap 504. The light trap 504 can thus prevent both
the micro-objects in the selected group 502 from mixing with any
other group 402 of micro-objects in the device 100 and any
micro-object that is not of the selected group 502 form mixing with
group 502 during step 302 of FIG. 3.
[0102] As shown in FIG. 7, once the selected group 502 is in the
staging area 172, the light trap 504 can be turned off. As shown in
FIG. 7, the flow 404 (see FIG. 4) of medium 144 can be turned off
so that the micro-objects of the selected group 502 are not flushed
from the staging area 172. Alternatively, the light trap 504 can be
kept on in the staging area 172 to hold the group 502 in place in
the staging area 172 against a flow of medium 144 in the flow
region 140. As yet another alternative, the staging area 172 can
include physical barriers (not shown) that can hold the group 502
in place against a flow of medium 144 in the flow region 140.
[0103] At step 304 of FIG. 3, the process 300 can export the group
502 of micro-objects from the staging area 172. FIGS. 8 and 9
illustrate an example.
[0104] As shown in FIG. 8, the cover 166 of the export interface
162 can be removed, and the export device 182 can be inserted into
the interface 162 such that the opening 190 in the first end 188 of
the export device 182 is in proximity or contact with the passage
174 into the enclosure 102. As shown in FIG. 8, the opening 190 in
the first end 188 of the export device 182 can thus be adjacent the
group 502 of micro-objects in the staging area 172.
[0105] As shown in FIG. 9, a pressure differential can be created
in the export device 182. The micro-objects in the group 502
disposed in the staging area 172 can thus be drawn through the
passage 174 into the enclosure 102 and into the interior 186 of the
export device 182. The micro-objects of the group 502 can then be
collected or otherwise disposed of at the second end 192 of the
export device 182. Alternatively, the export device 182 is not a
pressure differential generating device or a pressure differential
is not created, but another mechanism draws the micro-objects in
the group 502 into the export device 182. For example, a flow (not
shown) of the medium 140 can be generated that washes the
micro-objects in the group 502 from the staging area 172 into the
export device 182. Other forces that can be employed to export
micro-objects can include gravity and magnetic force. As yet
another alternative, a combination of forces can be used to draw
the micro-objects in the group 502 into the export device 182, such
as a flow of the medium 140 and a pressure differential generated
by the export device 182.
[0106] FIG. 10 is an example process 1000 by which step 304 of FIG.
3 can be performed. As will be seen, fluid flow can move the
micro-objects of the group 502 from the staging area 172 into the
export device 182. Such fluid flow can include the flow of the
medium 144 in the device 100, a pressure differential by the export
device 182, capillary forces by the export device 182, and the
like.
[0107] At step 1002, the flow 404 (see FIG. 4) of medium 144 in the
flow region 140 can be substantially stopped. For example, the
control module 130 can cause the flow controller 124 to
substantially stop the flow 404. Alternatively, the flow 404 can be
slowed at step 1002. At step 1004, the export device 182 can be
inserted into the export interface 162, for example, as shown in
FIG. 8. At step 1006, the outlet 110 of the micro-fluidic device
100 (see FIGS. 1A-1C) can be closed. Any other exits (not shown)
from the enclosure 102 other than the export interface 162 can also
be closed.
[0108] At step 1008, the flow 404 of medium 144 in the flow region
140 can be resumed. Because the export interface 162 is the only
open exit from the enclosure 102, the direction of the flow 404
will be toward and into the export interface 162, and the flow 404
can accordingly sweep the micro-objects of the group 502 from the
staging area 172 toward the export device 182.
[0109] At step 1010, a pressure differential in the export device
182 can be created, which can draw the micro-objects of the group
502 into the interior 186 of and toward the second end 192 of the
export device 182. Alternatively, no pressure differential is
created at step 1010, and the flow generated at step 1008 alone
(optionally coupled with other forces, such as gravity or magnetic
force) draws the micro-objects of the group 502 from the staging
area 172 into the export device 182. Some embodiments of the export
device 182 thus do not have pressure differential capability.
[0110] Once the group 502 of micro-objects has been drawn into the
export device 182, the flow 404 of medium 144 can again be
substantially stopped or slowed at step 1012, and the export device
182 can be optionally removed from the export interface 162 at step
1014. A pressure differential by the export device 182 can also be
turned off at step 1012 or 1014. At step 1016, the outlet 110 of
the micro-fluidic device 100 can be opened, and the flow 404 of
medium 144 in the flow region 140 can again be resumed at step
1018.
[0111] The process 1000 is an example only, and variations are
possible. For example, the order of the steps 1002-1018 can, in
some instances, be different than shown. In addition, not all steps
need to be performed. For example, the export device 182 can be
substantially permanently connected to the export interface 162,
making it possible to skip steps 1004 and 1014. Similarly, for
serial export of micro-objects from different holding pens 156, the
outlet 110 can be closed for the first export, but then remain
closed for subsequent exporting steps. Accordingly, step 1016 of
process 1000 can be skipped, steps 1006 and 1016 of process 1000
can be skipped, steps 1014 and 1016 of process 1000 can be skipped,
steps 1004, 1006, 1014, and 1006 of process 1000 can be skipped, or
steps 1004, 1006, and 1014 of process 1000 can be skipped.
[0112] Referring again to FIG. 3, at step 306, the process 300 can
neutralize any un-exported micro-objects at the staging area and
the export interface. For a variety of reasons, one or more of the
micro-objects of the group 502 might not be exported as part of
step 304. For example, a micro-object might unintentionally remain
in the staging area 172. As another example, a micro-object might
get stuck in the export interface 162.
[0113] For a variety of reasons, such un-exported micro-objects at
the staging area 172 and export interface 162 might need to be
neutralized. For example, in some applications, it can be important
to keep the micro-objects in one of the groups 402 from mixing with
the micro-objects in another of the groups 402 (see FIG. 4). For
example, as noted, each group 402 of micro-objects in the pens 156
can be a clonal colony of biological cells, in which case, it can
be important to prevent a living cell that is able to reproduce in
one group 402 from mixing with another group because the colony
into which the cell is mixed would no longer be clonal. If a
micro-object from the group 502 was left in the staging area 172 or
the export interface 162, the un-exported micro-object could mix
with the next group 402 of micro-objects to be removed from a
holding pen 156, moved into the staging area 172, and exported
through the export interface 162.
[0114] Step 306 can be performed in any of a variety of ways. For
example, the detector 138 can capture images of the staging area
172 and the export interface 162, and those images can be inspected
for un-exported micro-objects from group 502. The images can be
inspected by a human operator and/or utilizing image processing
algorithms executed by the control module 130. Any detected
micro-objects can be neutralized in any of a variety of possible
ways.
[0115] For example, un-exported micro-objects at the staging area
172 and/or the export interface 162 can be removed utilizing the
selector 122 (e.g., configured as the DEP device 200 of FIGS. 2A
and 2B), by flushing the un-exported micro-objects from the staging
area 172 and/or export interface 162, or the like. As another
example, step 306 can be performed by repeating step 304 one or
more times without first moving a new group of micro-objects into
the staging area 172 at step 302.
[0116] As another example, if the un-exported micro-objects are
biological cells, the un-exported biological cells can be
neutralized by sterilizing or killing the un-exported cells. FIG.
11 illustrates an example process 1100 for performing step 306 of
FIG. 3 when the micro-objects are biological micro-objects such as
cells. At step 1102, a treatment can be applied to the staging area
172 and the export interface 162. The treatment can kill or
sterilize the biological micro-objects. For example, the treatment
can comprise flushing a chemical agent that is fatal to or
sterilizes the biological micro-objects through the staging area
172 and export interface 162. As another example, the treatment can
comprise directing electromagnetic radiation that is fatal to or
sterilizes the biological micro-objects onto the staging area 172
and the export interface 162. For example, the EM source 136 can
direct laser beams onto the staging area 172 and the export
interface 162. In some embodiments, the detector 138 can capture
images of the staging area 172 and/or export interface 162, and
such laser beams can be specifically directed at any biological
micro-objects detected in the images. Other examples of killing or
sterilizing un-exported cells at the staging area 172 or the export
interface 162 include the use of electricity, heat or cold, lysis
(e.g., with a mechanical cutting micro-instrument), ultrasonic
vibrations, or the like.
[0117] At step 1104, the process 300 can flush the staging area 172
and export interface 162 to wash away any biological micro-objects
in the staging area 172 or export interface 162. For example, the
staging area 172 and export interface 162 can be flushed with
medium 144. As another example, the staging area 172 and export
interface 162 can be flushed with de-ionized water.
[0118] At step 1106, the staging area 172 and export interface 162
can be inspected for un-exported biological micro-objects. For
example, the detector 138 can capture images of the staging area
172 and export interface 162, which can be inspected for
un-exported biological micro-objects as discussed above. If
un-exported biological micro-objects are detected, the steps of
applying a treatment 1102 and flushing 1104 can be repeated until
no un-exported micro-objects are detected at step 1106.
[0119] The process 1100 of FIG. 11 is an example only, and
variations are contemplated. For example, the inspecting step 1106
can precede the treatment 1102 and flushing 1104 steps, which in
some embodiments, are thus performed only if un-exported
micro-objects are detected. As another example, the process 1100
can be performed without one or both of the flushing step 1104 or
the inspecting step 1106. As yet another example, the process 1100
can be performed without step 1102, such as by flushing un-exported
biological micro-objects into a waste receptacle.
[0120] Indeed, the devices and processes illustrated in FIGS. 1A-11
are examples, and variations are contemplated. FIGS. 12A-16
illustrate examples of such variations.
[0121] FIGS. 12A-12C illustrate another example of an export
interface 1202, which can thus replace the export interface 162 in
any of the figures or discussions herein. As shown, the export
interface 1202 can be disposed on the enclosure 102 over the
passage 174. The export interface 1202 can comprise an opening 1204
to the passage 174, a cover 1206 comprising a separation 1208
(e.g., a slit) and flaps 1210, and an entry opening 1222.
[0122] As shown in FIG. 12B, the separation 1208 can define and
thus separate the flaps 1210. For example, the separation 1208 can
comprise one or more slits in the cover 1206. Although the cover
1206 is illustrated as comprising one separation 1208 and two flaps
1210, the cover 1206 can comprise more separations 1208 and flaps
1210. Regardless, the cover 1206 can comprise a flexible, resilient
material, and the cover 1206 can be constructed such that internal
resilient forces bias the flaps 1210 into proximity or contact so
that the cover 1206 covers entirely or substantially entirely the
passage 174 through the enclosure 102. The flexibility of the flaps
1210, however, can allow the flaps 1210 to move apart in response
to the force of the first end 188 of the export device 182 being
pressed against the cover 1206 in the vicinity of the separation
1208. As illustrated in FIG. 12C, the flaps 1210 can move apart,
allowing the first end 188 of the export device 172 to be moved
into proximity or contact with the passage 174 into the enclosure
102. Although not shown, the resiliency of the flaps 1210 can move
the flaps 1210 back into contact such that the cover 1206 covers
entirely or substantially entirely the passage 174 as shown in FIG.
12B as the export device 174 is removed from the export interface
1202.
[0123] The cover 1206 can thus be closed except when the end 188 of
the export device 182 is pressed against and through the cover
1206, in which case the cover opens 1206 to receive the export
device 182. As the export device 182 is removed from the cover
1206, the cover 1206 self closes.
[0124] The entry 1222 portion of the export interface 1202 can
function as a guide that facilitates insertion of the export device
182 into the export interface 1202. As illustrated, the entry 1222
can comprise sloped sidewalls 1224.
[0125] FIGS. 13A-13C illustrate another example of an export
interface 1302, which can replace the export interface 162 in any
of the figures or discussions herein. As shown, the export
interface 1302 can be disposed on the enclosure 102 over the
passage 174. The export interface 1302 can comprise a block of
material that covers (and thus is a cover 166) entirely the passage
174 as shown in FIG. 13A. The material, however, can be
sufficiently pliant to be readily pierced by an export device 1304
as shown in FIG. 13B. In FIG. 13B, the export interface 1302 is
pierced by pressing a first end 1388 of an export device 1304,
which can be, for example, a hypodermic needle or the like, through
the export interface 1302, which thus forms a hole 1306 in the
export interface 1302. The export device 1304 can be especially
thin but otherwise generally like the export device 182. Thus,
while inserted through the export interface 1302 as shown in FIG.
13B, a first end 1388 of the export device 1304 can be in proximity
to or contact with the passage 174 into the enclosure 102, and
micro-objects (not shown in FIG. 13B) can be drawn into an opening
in the first end 1388 of the export device 1304 generally as
discussed above with respect to the export device 182. The export
device 1304 is thus an example of the export device 182 and can
replace the export device 182 in any of the figures or discussions
herein. The material of the export interface 1302 can be
self-healing so that the hole 1306 made by the export device 182
closes as the export device 1304 is removed from the export
interface 1302. Examples of a self-healing material for the export
interface 1302 include silicone. As illustrated in FIG. 13C, the
export device 1302 can be pierced multiple times in multiple places
by the export device 1304. Rather than being a structure separate
from the micro-fluidic structure 104, the export interface 1302 can
instead be a portion of the micro-fluidic structure 104 immediately
adjacent the staging area 172. In such a case, the structure 104
need not include the passage 174.
[0126] FIG. 14 shows yet another example of an export interface
1406, which can replace the export interface 162 in any of the
figures or discussions herein. In FIG. 14, the export interface
1406 can be a fixed attachment mechanism that permanently fixes an
access tube 1402 to the enclosure 102 such that a first end 1488 of
the tube 1402 is in proximity to or contact with the passage 174
into the enclosure 102. Micro-objects (not shown in FIG. 14) can be
drawn into an opening in the first end 1488 of the access tube 1402
generally as discussed above with respect to the export device 182.
The access tube 1402 is thus an example of the export device 182
and can replace the export device 182 in any of the figures or
discussions herein. As shown, the access tube 1402 can comprise a
valve 1408, which can open and close an interior passage in the
tube 1402 from the first end 1488 to the second end 1492. The valve
1408 can be, for example, closed except while exporting
micro-objects from the staging area 172. However, the access tube
1402 need not comprise a valve 1408, as capillary forces and
adjusting the rate of fluid flow through flow region 140 can
substitute for valve 1408.
[0127] FIG. 15A shows a partial perspective view of a micro-fluidic
device 1500 that can be an example of a variation of the device 100
of FIGS. 1A-1D. With a few exceptions, the micro-fluidic device
1500 can be like the device 100, and like numbered elements in
FIGS. 15A-15C can be the same as in FIGS. 1A-1D.
[0128] As shown in FIGS. 15A-15C, the export interface 162 can be a
first export interface of the micro-fluidic device 1500, which can
also include a second export interface 1562 disposed over a second
passage 1574 through the enclosure 102 into the flow region 140.
Otherwise, the second export interface 1562 can be similar to the
first export interface 162. For example, the second export
interface 1562 can comprise an opening 1564 to the passage 1574 and
a cover 1566, which can be similar to the opening 164 and cover 166
of the first export interface 162 as discussed above. As also
shown, the passages 174, 1574 into the enclosure 102 and thus the
export interfaces 162, 1562 can be on opposite sides of the
enclosure 102 and need not be aligned one with the other.
[0129] The micro-fluidic device 1500 can also have a staging area
1512 that differs from the staging area 172 of the device 100. For
example, as shown in FIGS. 15B and 15C, the staging area 1512 can
comprise a first end 1518, which can be generally aligned with the
passage 174 and thus the first export interface 162; a second end
1514, which can be generally aligned with the passage 1574 and thus
the second export interface 1562; and a middle portion 1516 between
the ends 1514, 1518. Otherwise, the staging area 1512 can be like
the staging area 172 of the device 100 as discussed above. The
device 100 can alternatively have a staging area like 1512, which
can thus replace the staging area 172 in FIGS. 1A-11 and the
discussions above.
[0130] The process 300 of FIG. 3 can be performed with the
micro-fluidic device 1500 as follows. Step 302 can be performed
generally as discussed above. For example, although not visible in
the views shown in FIGS. 15A-15C, the device 1500 can include
holding pens 156 each of which can hold a group 402 of
micro-objects, for example, as shown in FIG. 5. The holding pens
156 can include isolation spaces in which the groups 402 of
micro-objects are located. A group of micro-objects can be moved
from a holding pen 156 to the staging area or a portion thereof
(e.g., the middle portion 1516), generally as illustrated in FIGS.
4-7.
[0131] Step 304 can be performed as illustrated in FIG. 16. The
covers 166, 1566 of the export interfaces 162, 1562 can be removed,
and a first export device 182 can be inserted into the first
interface 162 such that the opening 190 in the first end 188 is in
proximity to or contact with the first passage 174 through the
enclosure 102. The first export device 182 can be the same as the
export device 182 discussed above, and the foregoing can be the
same as discussed above.
[0132] A second export device 1682 can similarly be inserted into
the second interface 1562. The second export device 1682 can be the
same as or similar to the first export device 182. The second
export device 1682 can thus comprise a hollow tube-like structure
comprising a tubular housing 1684 that defines an interior passage
1686 from a first end 1688 to an opposite second end 1692. With the
cover 1566 of the second export interface 1682 removed, the second
export device 1682 can be inserted into the opening 1564 in the
second export interface 1562 such that the first end 1688 is
brought into proximity or contact with the second passage 1574 into
the enclosure 102.
[0133] With the export devices 182, 1682 inserted into the export
interfaces 162, 1562 as illustrated in FIG. 16, a flow of liquid
(e.g., medium 144) can be generated between the opening 190 of the
first export device 182 to the opening 1690 of the second export
device 1582, with the flow of liquid passing through the portion of
flow region 140 adjacent to staging area 1512. To facilitate such a
flow of liquid, a pressure differential can be generated between
the opening 190 of the first export device 182 and the opening 1690
of the second export device 1582.
[0134] For example, as shown in FIG. 16, a flow of liquid (e.g.,
medium 144) can be generated from the second end 192 to the first
end 188 of the first export device 182. This can create a flow 1604
in the enclosure 102 from the first end 1518 to the second end 1514
of the staging area 1512. The flow 1604 can sweep the selected
group 502 of micro-objects from the middle portion 1516 of the
staging area 1512 toward the second end 1514 and thus the opening
1690 at the first end 1688 of the second export device 1682. At the
same time, a pressure differential can be generated from the first
end 1688 to the second end 1692 of the second export device 1682.
Such a pressure differential can draw the selected group 502 of
micro-objects through the second passage 1574 in the enclosure 102
and into the second export device 1682. The micro-objects of the
selected group 502 can then be collected at the second end 1692 of
the second export device 1682.
[0135] The selected group 502 of micro-objects moved to the staging
area 1512 at step 302 of FIG. 3 can thus be exported at step 304.
Thereafter, the staging area 1512, the first export interface 162,
and/or the second export interface 1562 can be flushed and/or
neutralized of un-exported micro-objects at step 306, generally as
discussed above.
[0136] FIG. 17 illustrates another variation of the device 100 of
FIGS. 1A-1D. As shown, the device 1700 of FIG. 17 can comprise a
plurality of staging areas 1772 each of which can be like the
staging area 172 as discussed above, and the device 1700 can
include a plurality of outlets 110a, 110b (which can be as the
outlets 110 are described above). In some embodiments, each staging
area 172 can be associated with a single holding pen 156.
Otherwise, the device 1700 can be like the device 100 of FIGS.
1A-1D and like numbered elements can be the same.
[0137] As illustrated in FIG. 17, a flow 1704 of the medium can be
directed to the staging areas 1772. For example, all of the outlets
110 except for outlet 110a can be closed, diverting fluid flow from
channel 152 and creating a single flow path 1752 generally from the
inlet 108 to the staging areas 1772 and to the only open outlet
110a. Micro-objects (not shown in FIG. 17) can be moved to a
staging area 1772 by simply moving the micro-objects from one of
the pens 156 into the flow 1704, which can then carry the
micro-objects to the staging areas 1772, where the micro-objects
(not shown) can be removed through an adjacent export interface
(not shown) as discussed above. Alternatively, in some embodiments,
micro-objects (not shown in FIG. 17) can be moved from one of the
pens 156 to a staging area 1772 and the flow 1704 can carry the
micro-objects to and out of the outlet 110a. The outlet 110a can
thus function as an export interface. The outlet 110a can be like
any of the examples of an outlet 110 discussed above, including a
simple hole through the enclosure 102.
[0138] FIG. 18 illustrates a variation of the device 1700 of FIG.
17. As shown, the device 1800 of FIG. 18 can be generally the same
as the device 1700 (and like numbered elements can be the same)
except the device 1800 includes a single barrier 1854 that defines
the holding pens 156 and divides channel 152 from flow path 1752.
In addition, device 1800 includes a single staging area 1772 (or
none at all) located in the flow path 1752. As discussed above with
respect to FIG. 17, a flow 1704 of the medium 144 can be created in
the flow path 1752 by closing all of the outlets 110 except for the
outlet 110a. Micro-objects (not shown in FIG. 18) can be exported
from the device 1800 by moving the micro-objects from one of the
pens 156 to the staging area 1772, where the micro-objects (not
shown) can be removed through an adjacent export interface (not
shown) as discussed above. Alternatively, micro-objects (not shown
in FIG. 18) can be exported from the device 1800 by moving the
micro-objects from one of the pens 156 to the staging area 1772 or
(if there is no staging area) into the flow 1704, and flow 1704 can
then carry the micro-objects to and out of the outlet 110a. The
outlet 110a can be like any of the examples of an outlet 110
discussed above including a simple hole through the enclosure
102.
[0139] FIGS. 19A-19B illustrate another variation of the device
1700 of FIG. 17. As shown, the device 1900 of FIGS. 19A-19B can be
generally the same as the device 1700 (and like numbered elements
can be the same) except the device 1900 includes a channel 152 that
also functions as flow path 1752. In the embodiment shown, each
staging area 1772 is located in the channel 152, adjacent to the
opening to a holding pen 156. However, the number of staging areas
in device 1900 can be less than the number of holding pens 156
and/or the staging areas need not have specific locations in
channel 152 (i.e., any location in channel 152 can be considered a
staging area 1772). As shown in FIG. 19B (a side, cross-section of
device 1900), the inlet 108 to and/or outlet 110 from flow region
140 can be located above flow region 140, and the outlet can
function as an export interface having a passage 174. The outlet
110 can be connected to an export device (not shown), generally in
the manner discussed above. Furthermore, the holding pens 156 can
have isolation regions 1960 and connection regions 1958, with the
isolation regions 1960 fluidically connected to the channel 152 via
the connection regions 1958. Micro-objects (not shown in FIGS.
19A-19B) can be exported from the device 1900 by moving the
micro-objects from one of the pens 156 to a staging area 1772 in
channel 152, and flow 1904 can then carry the micro-objects to the
outlet 110 and out into the export device.
[0140] FIG. 20 illustrates an example of a process 2000 for
exporting micro-objects from the device 1900 of FIGS. 19A-19B. As
shown, at step 2002, the process 2000 can create the flow 1904 of
medium 144 in the enclosure 102 of the device 1900 directly to the
outlet 110. For example, the flow 1904 can flush medium 144 through
channel 152 and out the outlet 110. The flush at step 2002 can
clear the device 1900 of micro-objects that may be present in
channel 152, around the outlet 110 (i.e., export interface), and/or
in the export device (not shown). In certain embodiments, the
amount of medium 144 flushed through the device 1900 at step 2002
is at least 2 times (e.g., at least 3, 4, 5, 10, 15, 20, 25 times,
or more) the combined volume of fluid that the device 1900 and
export device are capable of holding. The flushing medium can be
flowed into the channel at a rate of about 0.05 to 5.0 .mu.L/sec
(e.g., about 0.1 to 2.0, 0.2 to 1.5, 0.5 to 1.0 .mu.L/sec, or about
1.0 to 2.0 .mu.L/sec). The flow 1904 of medium at step 2002 can be
continuous, pulsed, periodic, random, intermittent, or
reciprocating flow of the liquid, or any combination thereof.
[0141] At step 2004, the process 2000 can include slowing or
substantially stopping the flow 1904 of medium 144 in channel 152.
For example, the flow 1904 of medium 144 in channel 152 can be
slowed to a rate of about 0.05 .mu.L/sec or less.
[0142] At step 2006, the process 2000 can select a group of
micro-objects in one of the holding pens 156 and, at step 2008,
move the selected group into the channel 152 (e.g., to a staging
area 1772 located adjacent to the opening of the pen 156 or some
other region of the channel 152). Although not shown in FIGS.
19A-19B, the holding pens 156 can contain groups of micro-objects
402 as illustrated in FIG. 5. Steps 2006 and 2008 can be performed,
for example, as illustrated in FIGS. 5-7 except the selected group
502 is moved into the channel 152 of FIGS. 19A-19B rather than the
staging area 172 of FIGS. 5-7. If a light trap (e.g., like light
trap 504 in FIGS. 5-7) is used to move the group of micro-objects
502, the light trap can be turned off once the micro-objects 502
are situated in the channel 152.
[0143] At step 2010, the flow 1904 of medium 144 in channel 152 can
be resumed and the selected group of micro-objects 502 can be
carried with the flow 1904 and exported through outlet 110, out
into the export device (not shown), and through the distal end of
the export device. During step 2010, the flow 1904 of medium 144 in
channel 152 can be resumed, for example, at a rate of about 0.05 to
0.25 .mu.L/sec (e.g., about 0.1 to 0.2 .mu.L/sec or about 0.14 to
0.15 .mu.L/sec). The flow 1904 of medium can be continuous, pulsed,
periodic, random, intermittent, or reciprocating flow of the
liquid, or any combination thereof.
[0144] For process 2000 (as well as processes 300 and 1000), the
export device can be configured to export medium 144 (or other
solution) into a receptacle, such as a test tube, a well in a
microtiter plate, or the like. The distal end of the export device
(e.g., second end 192 in FIG. 1D or second end 1692 in FIG. 16) can
contact the surface of a liquid contained in the receptacle,
thereby bringing the volume of exported medium 144 into direct
contact with the liquid in the receptacle. Alternatively, the
distal end of the export device can contact a bottom or side wall
of the receptacle. Such direct contact, whether with the receptacle
or a liquid contained in the receptacle, can assist with reducing
surface tension that might otherwise tend to keep the volume of the
exported medium 144 (or some fraction thereof) associated with the
export device.
[0145] Step 2010 of process 2000 can include discarding unwanted
medium 144 prior to exporting the selected group of micro-objects
502. Once the group of micro-objects 502 has been moved to a
staging area 1772 (e.g., the region of the channel 140 located
adjacent the opening of the holding pen 156 from which the selected
group of micro-objects 502 was removed), there will be a "leading
volume" of liquid medium 144 that occupies (i) the portion of the
channel 140 located between the staging area 1772 and the outlet
110, and (ii) the interior passage of the export device (not
shown), between the proximal end (e.g., first end 188 of export
device 182) and the distal end (e.g., second end 192 of export
device 182). As this leading volume of liquid medium 144 should not
contain any micro-objects, it may be desirable to discard it, for
example, to a waste receptacle accessible to the second end of the
export device. Accordingly, step 2010 can include flowing a volume
of liquid medium 144 equivalent to a leading volume through the
device 1900, such that the leading volume is discarded, then
completing export of the selected group of micro-objects 502. After
discarding the leading volume of liquid medium 144, but prior to
completing export of the group of micro-objects 502, the flow 1904
of liquid medium 144 in channel 140 can be slowed or substantially
stopped for a period of time sufficient to move the distal end of
the export device to a receptacle into which the group of
micro-objects 502 can be exported.
[0146] Once the selected group of micro-objects 502 have been
exported, step 2010 can further include neutralizing any
un-exported micro-objects that may be stuck in the channel 140,
outlet 110, and/or the export device. Any of the neutralizing
techniques discussed above can be utilized. For example, the
neutralizing technique can comprise or consist of flushing the
device 1900, including the export device. Such flushing can
constitute step 2002 of a new round of export.
[0147] In one variation on process 2000, the liquid medium 144 used
at step 2002 to flush the channel 140, the outlet 110, and/or the
export device (not shown) and at step 2010 to export the selected
group of micro-objects 502 can be replaced with an alternative
solution. The alternative solution can be suitable for processing
of the group of micro-objects 502 after they have been exported.
The solution can be, for example, a solution that doesn't support
cell growth, a solution that cells do not tolerate well for long
periods of time, or a solution compatible with or useful for
assaying biological activity. For example, the solution can be a
HEPES buffer, phosphate buffered saline (PBS), osmotically-balanced
sugar water, or the like. In this variation on process 2000, step
2010 can include a flushing step with liquid medium 144 such that
the alternative solution is washed out of device 1900. Provided
that steps 2002 through 2010 are performed rapidly, exposure of the
groups of micro-objects 402 (not shown) located in the isolation
regions of holding pens 156 to the alternative solution can be
limited, thereby substantially mitigating any damaging effect that
the alternative solution might otherwise have on the groups of
micro-objects 402.
[0148] Any of the foregoing steps of process 2000, such as
discarding a leading volume of liquid medium 144, or flushing and
exporting in a solution different from liquid medium 144, and any
of the specific conditions, such as flow rates and the like, can be
likewise applied in processes 300 or 1000, as appropriate.
[0149] For any of processes 300, 1000, or 2000, the selected group
of micro-objects 502 being exported can be exported in a
pre-determined volume of medium 144 (or other solution). The volume
of medium 144 can depend on the number of micro-objects in the
group and how the group of micro-objects 502 is going to be
processed after export. Thus, for example, the group of
micro-objects 502 can be exported in a volume of medium 144 that is
less than 5 .mu.L (e.g., less than 4 .mu.L, 3 .mu.L, 2 .mu.L, 1
.mu.L, 750 nL, 500 nL, 250 nL, 200 nL, 150 nL, 100 nL, 75 nL, 50
nL, or less). Alternatively, the group of micro-objects 502 can be
exported in a volume that is about 1 to 10 .mu.L, 5 to 15 .mu.L, 10
to 20 .mu.L, 15 to 25 .mu.L, 20 to 30 .mu.L, 25 to 35 .mu.L, 30 to
40 .mu.L, 35 to 45 .mu.L, 40 to 50 .mu.L, or any range defined by
two of the foregoing endpoints. For single cell genomics
applications or the like, the group of micro-objects 502 can
consist of a single cell and the volume of exported medium 144 that
contains the single cell can be relatively small (e.g., less than 5
.mu.L). For cell line development or clonal expansion of cells, the
group of micro-objects can include a plurality of cells and the
volume of exported medium 144 that contains the plurality of cells
can be relatively large (e.g., 5 .mu.L, 10 .mu.L, 25 .mu.L, 50
.mu.L, or more). For assaying activity associated with
micro-objects, the group of micro-objects 502 can include one or a
plurality of micro-objects and the volume of exported medium 144
that contains the group of micro-objects 502 can be relatively
small or relatively large, as appropriate for the particular
assay.
[0150] To prevent dilution and/or evaporation of the exported
volume of medium 144, particularly when the volume of exported
medium 144 is small (e.g., 1 .mu.L or less), the volume of exported
medium 144 (containing the group of micro-objects) can be exported
into a non-aqueous liquid, such as an oil (e.g., mineral oil).
Alternatively, the volume of exported medium 144 can be exported
into culture medium (e.g., fresh cell growth medium), assay medium
(e.g., containing appropriate assay components), or some other
solution (e.g., PBS, cell lysis buffer, and the like) suitable for
subsequent processing of the micro-objects contained within the
volume of exported medium 144.
[0151] For any of processes 300, 1000, or 2000, the selected group
of micro-objects 502 can be exported individually or in series with
other groups of selected micro-objects (i.e., the processes 300,
1000, and 2000 can be repeated). In some embodiments, exporting
groups of micro-objects in series involves repeating specific steps
of the process, while other steps in the process are not repeated.
For example, in process 2000 steps 206 and 208 can be repeated a
plurality of times without repeating steps 2002, 2004, and 2010,
resulting in a plurality of selected groups of micro-objects 502
being present in channel 140. During export at step 2010,
pre-determined volumes of liquid medium 144 can be serially
exported into different receptacles. By adjusting the
pre-determined volume of liquid medium 144 such that the volume
contains only a single group of selected micro-objects, mixing
between the plurality of selected groups of micro-objects can be
avoided. FIGS. 21A-21C illustrate additional variations of the
devices disclosed herein (e.g., device 100 of FIGS. 1A-1D or device
1900 of FIGS. 19A-19B). As shown, the device 2100 of FIG. 21A can
comprise a passage 174 through the micro-fluidic structure 104 and
an export interface 1302 in the form of a pierceable cover adjacent
each of the holding pens 156 so that a hypodermic needle 1304 or
other such export device can pierce the interface 1302 and remove
micro-objects (not shown in FIG. 21A) directly from a pen 156. Each
passage 174, each export interface 1302, and the hypodermic needle
1304 can otherwise be the same as like numbered elements in FIGS.
13A-13C. Moreover, the device 2100 can otherwise be like the device
100 of FIGS. 1A-1D or the device 1900 of FIGS. 19A-19B, and like
numbered elements can be the same. FIGS. 21B and 21C show different
ways in which the export interface 1302 can be adjacent to a
holding pen 156. In FIG. 21B, the holding pen 156 includes an
isolation region 1960, a portion of which forms a staging area 2172
above which the export interface 1302 can be located. Micro-objects
204 (not shown) located in the staging area 2172 portion of the
holding pen 156 are thus accessible for direct export from the
holding pen 156. In FIG. 21C, the holding pen 156 includes an
isolation region 1960 that is connected (in this case, by means of
a passage) to a staging area 2172 above which the export interface
1302 can be located. As a group of micro-objects 402 (not shown),
such as a population of cells, multiplies in the isolation region
1960 of the holding pen 156 of FIG. 21C, cells will begin moving
into the staging area. Such movement can be achieved, for example,
by a force that includes gravity. Again, once micro-objects are
present in the staging area 2172, they are accessible for direct
export from the holding pen 156.
[0152] Rather than an export interface 1302 in the form of a
piercable cover 1302 and an export device in the form of a
hypodermic needle 1304 as shown in FIG. 21A, the device 2100 can
utilize any export interface and export device illustrated and
described herein. For example, the export interface 162 of FIGS.
1A-1D can replace any or all of the export interfaces 1302 in FIG.
21A, and the export device 182 can replace the hypodermic needle
1304. As another example of a variation of the device 2100, rather
than being a structure separate from the micro-fluidic structure
104, the export interface 1302 can instead be a portion of the
micro-fluidic structure 104 immediately adjacent a pen. In such a
case, the structure 104 need not include passages 174.
[0153] Methods of export that involve direct export from a holding
pen 156 can be used to export a selected group of micro-objects 502
in a very small volume of fluid medium 144 (or other solution). For
example, the export device (such as a hypodermic needle 1304) can
have a small volume of air located within the proximal end (i.e.,
the first end 1388 that gets inserted into/through the export
interface 1302) prior to being inserted through the export
interface 1302. Upon insertion, the export device can take up
(e.g., aspirate up) a pre-determined volume of liquid medium 144
that includes the selected group of micro-objects 502. The export
device can then be removed from the export interface 1302 and moved
to an appropriate receptacle, whereupon the volume of liquid medium
144 (along with the group of micro-objects 502) taken up by the
export device is expelled into the receptacle. The air located
within the proximal end of the export device can thus prevent the
exported volume of liquid medium 144 from mixing with fluid that
would otherwise be present in the export device. In addition, by
avoiding an export path that goes through the channel 152, export
interface 162, and/or the length of the interior passage of the
export device 182, an increase in exported volume due to the
selected group of micro-objects 502 spreading out as they travel
and/or a loss of micro-objects along the export path can be
avoided. Moreover, the export device in this embodiment (e.g., a
hypodermic needle 1304) can be readily cleaned and/or un-exported
micro-objects can readied for further use by flushing the export
device with a solution, such as a cleaning or neutralizing
solution. By flushing the solution through the export device and
into an external waste receptacle, introduction of potentially
harmful chemicals into the microfluidic device (e.g., device 100,
1700, 1800, 1900, or the like) can be avoided.
[0154] Any of the steps of the process 300, 1000, 1100, 2000 of
FIGS. 3, 10, 11, and 20 can be performed with the export interfaces
1202, 1302, 1406 in FIGS. 12A-12C, 13A and 13B, and 1406 or the
outlet 110a of FIG. 17 or 18 in place of the export interface 162
and/or the export interface 1562 in FIGS. 1A-11 and 15A-16.
Likewise, any of the steps of the process 300, 1000, 1100, 2000 of
FIGS. 3, 10, 11, and 20 can be performed with the export devices
1304, 1402 of FIGS. 13A-14 in place of the export devices 162, 1682
in FIGS. 1A-11 and 16. Similarly, the process 300, 1000, 1100, 2000
of FIGS. 3, 10, 11, and 20 can be performed with the micro-fluidic
devices 1500, 1700, 1800, 1900, 2100 of FIGS. 15A-19B and 21A-C
rather than the device 100.
[0155] Although specific embodiments and applications of the
invention have been described in this specification, these
embodiments and applications are exemplary only, and many
variations are possible. For example, although the passages 174 are
illustrated in the drawings as passing through the top of the
enclosure 102, the passages 174 can alternatively be through a side
or the bottom of the enclosure 102, and the export interfaces 162,
1202, 1302, 1406 (or outlets 110, 110a) can accordingly be on the
side or the bottom of the enclosure 102.
* * * * *