U.S. patent application number 14/262200 was filed with the patent office on 2015-10-29 for providing dep manipulation devices and controllable electrowetting devices in the same microfluidic apparatus.
This patent application is currently assigned to Berkeley Lights, Inc.. The applicant listed for this patent is Berkeley Lights, Inc.. Invention is credited to Igor Y. Khandros, Daniele Malleo, J. Tanner Nevill, Steven W. Short, Ming C. Wu.
Application Number | 20150306599 14/262200 |
Document ID | / |
Family ID | 54333899 |
Filed Date | 2015-10-29 |
United States Patent
Application |
20150306599 |
Kind Code |
A1 |
Khandros; Igor Y. ; et
al. |
October 29, 2015 |
Providing DEP Manipulation Devices And Controllable Electrowetting
Devices In The Same Microfluidic Apparatus
Abstract
A structure for providing a boundary for a chamber in a
microfluidic apparatus can comprise dielectrophoresis (DEP)
configurations each having an outer surface and electrowetting (EW)
configurations each having an electrowetting surface. The DEP
configurations can facilitate generating net DEP forces with
respect to the outer surfaces of the DEP configurations to move
micro-objects on the outer surfaces, and the EW configurations can
facilitate changing wetting properties of the electrowetting
surfaces to move droplets of liquid medium on the electrowetting
surfaces.
Inventors: |
Khandros; Igor Y.; (Orinda,
CA) ; Malleo; Daniele; (El Cerrito, CA) ;
Nevill; J. Tanner; (El Cerrito, CA) ; Short; Steven
W.; (Pleasanton, CA) ; Wu; Ming C.; (Moraga,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Berkeley Lights, Inc. |
Emeryville |
CA |
US |
|
|
Assignee: |
Berkeley Lights, Inc.
Emeryville
CA
|
Family ID: |
54333899 |
Appl. No.: |
14/262200 |
Filed: |
April 25, 2014 |
Current U.S.
Class: |
204/547 ;
204/643 |
Current CPC
Class: |
B01L 3/502792 20130101;
B01L 2300/0819 20130101; B01L 2200/0647 20130101; B01L 2400/0424
20130101; B03C 5/005 20130101; B03C 5/026 20130101; B01L 2400/0427
20130101; B03C 2201/26 20130101; B01L 2300/0816 20130101; B01L
3/502761 20130101 |
International
Class: |
B01L 3/00 20060101
B01L003/00 |
Claims
1. A structure comprising: a dielectrophoresis (DEP) configuration
comprising an outer surface; and an electrowetting (EW)
configuration comprising an electrowetting surface, wherein said
DEP configuration is disposed adjacent to said EW configuration
such that said outer surface of said DEP configuration is adjacent
to said electrowetting surface.
2. The structure of claim 1, wherein said DEP configuration
comprises: a first electrode; and a switchable element disposed
between said outer surface and said first electrode, wherein said
switchable element is configured to temporarily create an
electrically conductive first path from a first region of said
outer surface through said switchable element to said first
electrode.
3. The structure of claim 2, wherein said EW configuration
comprises: a second electrode, a dielectric layer disposed between
said electrowetting surface and said second electrode, and a
switchable element disposed between said dielectric layer and said
second electrode, wherein said switchable element is configured to
temporarily create an electrically conductive second path through
said switchable element and thereby change a wetting property of a
second region of said electrowetting surface adjacent to said
path.
4. The structure of claim 3, wherein: said switchable element of
said DEP configuration comprises a photoconductive material, and
selectively illuminating a portion of said photoconductive material
adjacent to said first region reduces an impedance of said portion
creating said first path.
5. The structure of claim 3, wherein said switchable element of
said DEP configuration comprises a switch from said first region of
said outer surface through said switchable element to said first
electrode.
6. The structure of claim 5, wherein said switch is light
activated.
7. The structure of claim 5, wherein said switch comprises a
transistor embedded in said switchable element.
8. The structure of claim 5, wherein said switchable element
further comprises isolation barriers in said switchable element
about said switch.
9. The structure of claim 8, wherein said switchable element of
said EW configuration comprises photoconductive material disposed
in said isolation barriers.
10. The structure of claim 3, wherein said outer surface of said
DEP configuration is substantially parallel to said electrowetting
surface of said EW configuration.
11. The structure of claim 10 further comprising a monolithic
component, wherein: a first section of said monolithic component
comprises said switchable element of said DEP configuration, and a
second section of said monolithic component comprises said
switchable element of said EW configuration.
12. The structure of claim 10 further comprising a support
structure, wherein: a first section of said support structure
comprises said switchable element of said EW configuration, and
said EW configuration is disposed in a cavity in a second section
of said support structure adjacent to said first section.
13. The structure of claim 1, wherein: said DEP configuration is a
first distinct device, and said EW configuration is a second
distinct device disposed adjacent to said DEP configuration, and
said outer surface of said DEP configuration is substantially
parallel to said electrowetting surface of said EW
configuration.
14. The structure of claim 1, wherein said EW configuration
comprises: a first electrode, a dielectric layer disposed between
said electrowetting surface and said first electrode, and a
switchable element disposed between said dielectric layer and said
first electrode, wherein said switchable element is configured to
temporarily create an electrically conductive path through said
switchable element and thereby change a wetting property of a
region of said electrowetting surface adjacent to said path.
15. The structure of claim 14, wherein said switchable element of
said EW configuration comprises a photoconductive material.
16. The structure of claim 14, wherein said switchable element of
said EW configuration comprises a switch through said switchable
element to said first electrode.
17. The structure of claim 1, wherein said outer surface of said
DEP configuration and said electrowetting surface of said EW
configuration are substantially parallel.
18. The structure of claim 17, wherein said outer surface of said
DEP configuration and said electrowetting surface of said EW
configuration are substantially in a same plane.
19. The structure of claim 17, wherein said outer surface of said
DEP configuration and said electrowetting surface of said EW
configuration form a substantially continuous composite
surface.
20. The structure of claim 1 further comprises: a plurality of said
DEP configurations each comprising an outer surface, and a
plurality of said EW configurations each comprising an
electrowetting surface, wherein at least some of said DEP
configurations and said EW configurations are disposed such that
said outer surfaces and said electrowetting surfaces are in
alternating patterns.
21. The structure of claim 20, wherein said outer surfaces of said
DEP configurations and said electrowetting surfaces of said EW
configurations are substantially in a same plane.
22. The structure of claim 20, wherein said outer surfaces of said
DEP configurations and said electrowetting surfaces of said EW
configurations form a substantially continuous composite
surface.
23. The structure of claim 20, wherein: said outer surfaces of said
DEP configurations are hydrophilic, and said electrowetting
surfaces of said EW configurations are hydrophobic.
24. A process of operating a microfluidic apparatus comprising a
chamber, dielectrophoresis (DEP) devices, and electrowetting (EW)
devices, said process comprising: moving a micro-object from a
first outer surface of a first of said DEP devices to a second
surface of a second of said DEP devices by activating said second
DEP device and thereby creating a net DEP force on said
micro-object in a direction of said second DEP device; and moving a
droplet of a liquid medium from a first location to a second
location in said chamber by activating a second of said EW devices
and thereby changing a wetting property of a second electrowetting
surface of said second EW device, wherein: in said first location
said droplet is disposed in part on a first electrowetting surface
of a first of said EW devices but not on said second electrowetting
surface of said second EW device, and in said second location said
droplet is disposed in part on said second electrowetting surface
of said second EW device but not on said first electrowetting
surface of said first EW device.
25. The process of claim 24, wherein said moving said droplet
comprises moving part of said droplet over an outer surface of one
of said DEP devices disposed between said first EW device and said
second EW device.
26. The process of claim 25, wherein: said outer surface of said
one of said DEP devices is hydrophilic, and said first
electrowetting surface and said second electrowetting surface are
hydrophobic.
27. The process of claim 26, wherein said changing said wetting
property of said second electrowetting surface comprises
temporarily reducing a hydrophobicity of said second electrowetting
surface.
28. The process of claim 26, wherein said changing said wetting
property of said second electrowetting surface comprises
temporarily changing said second electrowetting surface from
hydrophobic to hydrophilic.
29. The process of claim 24, wherein said moving said micro-object
comprises moving said micro-object from said first outer surface
across an electrowetting surface of an adjacent to one of said EW
devices to said second outer surface.
30. The process of claim 24, wherein: a structural boundary of said
chamber comprises said first outer surface, said second outer
surface, said first electrowetting surface, and said second
electrowetting surface, and said process further comprises
performing both of said moving steps simultaneously.
31. The process of claim 24, wherein: a micro-object is disposed in
said droplet, and said moving said droplet further comprises said
micro-object moving with said droplet.
32. A process of manipulating a droplet of liquid medium in a
microfluidic apparatus comprising a chamber, dielectrophoresis
(DEP) devices, and electrowetting (EW) devices, said process
comprising: disposing a droplet of a first liquid medium on first
outer surfaces of a first set of said DEP devices and first
electrowetting surfaces of a first set of said EW devices;
separating a first part of said droplet from a second part of said
droplet by activating second electrowetting surfaces of a second
set of said EW devices and thereby changing a wetting property of
said second electrowetting surfaces.
33. The process of claim 32, wherein said separating comprises
moving said first part of said droplet from a first location
comprising said first outer surfaces of said first DEP devices and
said first electrowetting surfaces of said first EW devices to a
second location comprising second outer surfaces of a second set of
said DEP devices and said second electrowetting surfaces of said
second set of said EW devices.
34. The process of claim 33, wherein said separating comprises:
activating third electrowetting surfaces of a third set of said EW
devices disposed between said first set of said EW devices and said
second set of said EW devices, and thereafter activating said
second electrowetting surfaces of said second set of EW
devices.
35. The process of claim 34, wherein: none of said DEP devices in
said second set of DEP devices is also in said first set of DEP
devices, none of said EW devices in said second set of EW devices
is also in said first set of EW devices or said third set of EW
devices, and none of said EW devices in said EW devices in said
first set of EW devices is also in said third set of EW
devices.
36. The process of claim 34, wherein said second location is
separated from and does not overlap said first location.
37. The process of claim 33, wherein said separating said first
part of said droplet comprises a first group of micro-objects
disposed in said first part of said droplet moving with said first
part of said droplet from said first location to said second
location.
38. The process of claim 33 further comprising, prior to said
separating said first part of said droplet, selecting said first
group of micro-objects from a larger group of micro-objects in said
droplet.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application is related to the U.S. patent application
Ser. No. ______ entitled "DEP Force Control And Electrowetting
Control In Different Sections Of The Same Microfluidic Apparatus"
(attorney docket no. BL21-US) filed Apr. 25, 2014, which is
incorporated herein by reference in its entirety.
BACKGROUND
[0002] Micro-objects, such as biological cells, can be processed in
a microfluidic apparatus. For example, micro-objects suspended in a
liquid in a microfluidic apparatus can be sorted, selected, and
moved in the apparatus. The liquid can also be manipulated in the
device. Embodiments of the present invention are directed to
improvements in manipulating micro-objects and liquid in the same
microfluidic apparatus.
SUMMARY
[0003] In some embodiments, a structure can comprise a
dielectrophoresis (DEP) configuration comprising an outer surface
and an electrowetting (EW) configuration comprising an
electrowetting surface. The DEP configuration can be disposed
adjacent to the EW configuration such that the outer surface of the
DEP configuration is adjacent to the electrowetting surface.
[0004] Some embodiments of the invention can be directed to a
process of operating a microfluidic apparatus comprising a chamber,
dielectrophoresis (DEP) devices, and electrowetting (EW) devices.
The process can include moving a micro-object from a first outer
surface of a first of the DEP devices to a second outer surface of
a second of the DEP devices. This can be accomplished by activating
the second DEP device and thereby creating a net DEP force on the
micro-object in a direction of the second DEP device. The process
can further include moving a droplet of a liquid medium from a
first location to a second location in the chamber by activating a
second of the EW devices and thereby changing a wetting property of
a second electrowetting surface of the second EW device. In the
first location, the droplet can be disposed in part on a first
electrowetting surface of a first of the EW devices but not on the
second electrowetting surface of the second EW device. In the
second location, the droplet can be disposed in part on the second
electrowetting surface of the second EW device but not on the first
electrowetting surface of the first EW device.
[0005] Some embodiments of the invention can be directed to such a
process that includes disposing a droplet of a first liquid medium
on first outer surfaces of a first set of the DEP devices and first
electrowetting surfaces of a first set of the EW devices. The
process can also include separating a first part of the droplet
from a second part of the droplet by activating second
electrowetting surfaces of a second set of the EW devices and
thereby changing a wetting property of the second electrowetting
surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 illustrates a perspective view of an example of a
microfluidic apparatus with a structure comprising
dielectrophoresis (DEP) configurations and electrowetting (EW)
configurations according to some embodiments of the invention.
[0007] FIG. 2A is a partial, cross-sectional, side view of an
example of a DEP device comprising one of the DEP configurations of
FIG. 1 according to some embodiments of the invention.
[0008] FIG. 2B shows an embodiment of a switchable element of the
DEP device of FIG. 2A comprising a photoconductive material in
which low impedance electrical paths can be created with a beam of
light according to some embodiments of the invention.
[0009] FIG. 3 is an example of an embodiment of a switchable
element of the DEP device of FIG. 2A comprising switches for
temporarily creating low impedance electrical paths between a
biasing electrode and an outer surface of the switchable element
according to some embodiments of the invention.
[0010] FIG. 4 shows an example in which the switches of FIG. 3 are
implemented as transistors according to some embodiments of the
invention.
[0011] FIG. 5A is a partial, cross-sectional, side view of an
example of an EW device comprising one of the EW configurations of
FIG. 1 according to some embodiments of the invention.
[0012] FIG. 5B shows an embodiment of a switchable element of the
EW device of FIG. 5A comprising a photoconductive material in which
a low impedance electrical path can be created with a beam of light
according to some embodiments of the invention.
[0013] FIG. 6 is an example of an embodiment of the switchable
element of the EW device of FIG. 5A comprising switches for
temporarily creating low impedance electrical paths between a
biasing electrode and an outer surface of the switchable element
according to some embodiments of the invention.
[0014] FIG. 7 illustrates an example in which a structure of the
microfluidic apparatus of FIG. 1 comprises DEP configurations and
EW configurations integrated into a single, monolithic switchable
element according to some embodiments of the invention.
[0015] FIG. 8 shows an example in which the structure of the
microfluidic apparatus of FIG. 1 comprises structurally distinct
DEP configurations and structurally distinct EW configurations
according to some embodiments of the invention.
[0016] FIG. 9 is an example in which a structure of the
microfluidic apparatus of FIG. 1 comprises a support structure,
where DEP configurations are integrated into sections of the
support structure and stand alone distinct EW configurations are
disposed in cavities in the support structure according to some
embodiments of the invention.
[0017] FIG. 10 shows an example in which a structure of the
microfluidic apparatus of FIG. 1 comprises DEP configurations in
which switches are embedded into a switchable element and EW
configurations that comprise photoconductive material in embedded
isolation barriers according to some embodiments of the
invention.
[0018] FIG. 11 illustrates an embodiment of the microfluidic
apparatus of FIG. 1 comprising DEP devices and EW devices disposed
in alternating patterns according to some embodiments of the
invention.
[0019] FIGS. 12A-12C show partial, cross-sectional, side views of
the enclosure of FIG. 11 and illustrate an example of operation of
the microfluidic apparatus of FIG. 11 according to some embodiments
of the invention.
[0020] FIG. 13 is an example of a process for operating the
apparatus of FIG. 11 in accordance with the operations illustrated
in FIGS. 12A-12C according to some embodiments of the
invention.
[0021] FIGS. 14A-14C show top views of the enclosure of FIG. 11
with the cover removed and illustrate another example of operation
of the microfluidic apparatus of FIG. 11 according to some
embodiments of the invention.
[0022] FIG. 15 is an example of a process for operating the
apparatus of FIG. 11 in accordance with the operations illustrated
in FIGS. 14A-14C according to some embodiments of the
invention.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0023] 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. 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 to, 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. The same reference numbers are used
throughout the drawings and specification to refer to the same
element.
[0024] 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. When used with respect to
numerical values or parameters or characteristics that can be
expressed as numerical values, "substantially" means within ten
percent. The term "ones" means more than one.
[0025] As used herein, the term "micro-object" can encompass one or
more of the following: inanimate micro-objects such as
micro-particles, micro-beads, micro-wires, and the like; biological
micro-objects such as cells (e.g., proteins, embryos, plasmids,
oocytes, sperms, hydridomas, and the like); and/or a combination of
inanimate micro-objects and biological micro-objects (e.g.,
micro-beads attached to cells).
[0026] The phrase "relatively high electrical conductivity" is used
herein synonymously with the phrase "relatively low electrical
impedance," and the foregoing phrases are interchangeable.
Similarly, the phrase "relatively low electrical conductivity" is
used synonymously with the phrase "relatively high electrical
impedance," and the foregoing phrases are interchangeable.
[0027] A "fluidic circuit" means one or more fluidic structures
(e.g., chambers, channels, pens, reservoirs, or the like), which
can be interconnected. A "fluidic circuit frame" means one or more
walls that define all or part of a fluidic circuit. A "droplet" of
liquid medium includes a single droplet or a plurality of droplets
that together form a single volume of the liquid medium.
[0028] Some embodiments of the invention include a structure
comprising a structural boundary (e.g., a floor, ceiling, or side)
of a chamber or other fluidic structure in a microfluidic
apparatus. The structure can comprise one or more dielectrophoresis
(DEP) configurations each having an outer surface and one or more
electrowetting (EW) configurations each having an electrowetting
surface. The boundary can comprise the outer surfaces of the DEP
configurations and the electrowetting surfaces of the EW
configurations. The DEP configurations can facilitate generating
net DEP forces with respect to the outer surfaces of the DEP
configurations to move micro-objects on the outer surfaces, and the
EW configurations can facilitate changing a wetting property of the
electrowetting surfaces to move droplets of liquid medium. Such a
structure can be part of a microfluidic apparatus, and can thus
provide in one microfluidic apparatus the ability both to
manipulate micro-objects on the outer surfaces of the DEP
configurations and to manipulate droplets of medium on the
electrowetting surfaces of the EW configurations.
[0029] FIG. 1 illustrates an example of a microfluidic apparatus
100 that can include a structure 104 that comprises both DEP
configurations 122 and EW configurations 126. Also shown are
examples of control equipment 132 for controlling operation of the
apparatus 100. Although the apparatus 100 can be physically
structured in many different ways, in the example shown in FIG. 1,
the apparatus 100 is depicted as including an enclosure 102 that
comprises a structure 104 (e.g., a base), a fluidic circuit frame
108, and a cover 110, which define a fluidic chamber 112 in which
one or more liquid media can be disposed.
[0030] As noted, the structure 104 can comprise one or more DEP
configured sections 122 (hereinafter "DEP configurations") and one
or more EW configured sections 126 (hereinafter "EW
configurations"). Each DEP configuration 122 can comprise an outer
surface 124 and can be configured to temporarily create a net DEP
force on a micro-object (not shown in FIG. 1) in a liquid medium
(not shown in FIG. 1) on the outer surface 124. In some
embodiments, the outer surface 124 can be hydrophilic. Each EW
configuration 126 can comprise an electrowetting surface 128 and
can be configured to temporarily change a wetting property of the
electrowetting surface 128 or a region of the electrowetting
surface 128. For example, the electrowetting surface 128 can be
hydrophobic but the EW configuration 126 can be configured to
temporarily change the electrowetting surface 128 or a region of
the electrowetting surface 128 to be less hydrophobic or even
hydrophilic.
[0031] Although FIG. 1 illustrates the structure 104 as comprising
one relatively large DEP configuration 122 with multiple EW
configurations 126 disposed in the DEP configuration 122, the
foregoing is but an example. As another example, the structure 104
can comprise one relatively large EW configuration 126 (e.g., in
place of the DEP configuration 122 in FIG. 1) and multiple DEP
configurations 122 (e.g., in place of the EW configurations 126 in
FIG. 1). As yet another example, the structure 104 can comprise
multiple DEP configurations 122 and multiple EW configurations
126.
[0032] Regardless, the structure 104 can comprise a structural
boundary 106 (e.g., a floor, ceiling, or side) of one or more
fluidic portions of a fluidic circuit defined by the fluidic
circuit frame 108. In the example shown in FIG. 1 the structural
boundary 106 can be a floor of the chamber 112 as shown.
Regardless, the structural boundary 106 can comprise the outer
surfaces 124 of the DEP configurations 122 and the electrowetting
surfaces 128 of the EW configurations 126. The boundary 106 of the
structure 104 can thus be a composite surface of one or more outer
surfaces 124 of one or more DEP configurations 122 and one or more
electrowetting surfaces 128 of one or more EW configurations
126.
[0033] The outer surfaces 124 and the electrowetting surfaces 128
can be substantially parallel. In some embodiments, the outer
surfaces 124 and the electrowetting surfaces 128 can also be in
substantially the same plane (e.g., as illustrated in FIGS. 1 and
8), and the structural boundary 106 of the structure 104 can thus
be substantially planar. In other embodiments, the outer surfaces
124 and the electrowetting surfaces 128 are not in the same plane
but can nevertheless be substantially parallel (e.g., as in the
example shown in FIG. 7).
[0034] Each DEP configuration 122 (and thus each outer surface 124)
and each EW configuration 126 (and thus each electrowetting surface
128) can have any desired shape. Moreover, the DEP configurations
122 (and thus the outer surfaces 124) and the EW configurations 126
(and thus the electrowetting surfaces 128) can be disposed in any
desired pattern. FIG. 11 (which is discussed below) illustrates an
example in which the structure 104 comprises multiple DEP
configurations 122 and multiple EW configurations 126 disposed in
alternating patterns.
[0035] As shown in FIG. 1, the fluidic circuit frame 108 can be
disposed on the structure 104 (e.g., on the boundary 106 of the
structure 104), and the cover 110 can be disposed over the fluidic
circuit frame 108. With the boundary 106 of the structure 104 as
the bottom and the cover as the top 110, the fluidic circuit frame
108 can define a fluidic circuit comprising, for example,
interconnected fluidic chambers, channels, pens, reservoirs, and
the like. In the example illustrated in FIG. 1, the fluidic circuit
frame 108 defines a chamber 112, and the boundary 106 of the
structure 104 can be, for example, a lower boundary of the chamber
112. Although the structure 104 is shown in FIG. 1 as comprising
the bottom of the apparatus 100 and the cover 110 is illustrated as
the top, the structure 104 can be the top and the cover 110 can be
the bottom of the apparatus 100. As also shown, the chamber 112 can
include one or more inlets 114 and one or more similar outlets (not
shown).
[0036] The structure 104 can comprise, for example, a substrate or
a plurality of interconnected substrates. For example, the
structure 104 can comprise a semiconductor substrate, a printed
circuit board substrate, or the like. The fluidic circuit frame 108
can comprise a flexible material (e.g. rubber, plastic, an
elastomer, silicone, polydimethylsioxane ("PDMS"), or the like),
which can be gas permeable. The cover 110 can be an integral part
of the fluidic circuit frame 108, or the cover 110 can be a
structurally distinct element (as illustrated in FIG. 1). The cover
110 can comprise the same or different materials than the fluidic
circuit frame 108. Regardless, the cover 110 and/or the structure
104 can be transparent to light.
[0037] FIG. 1 also illustrates examples of control equipment 132
that can be utilized with the microfluidic apparatus 100. Examples
of such control equipment 132 include a master controller 134, a
DEP module 142 for controlling the DEP devices 120 of which the DEP
configurations 122 of the structure 104 are a part, and an EW
module 144 for controlling EW devices 130 of which the EW
configurations 126 of the structure 104 are a part. The control
equipment 132 can also include other modules 140 for controlling,
monitoring, or performing other functions with respect to the
microfluidic apparatus 100.
[0038] The master controller 134 can comprise a control module 136
and a digital memory 138. The control module 136 can comprise, for
example, a digital processor configured to operate in accordance
with machine executable instructions (e.g., software, firmware,
microcode, or the like) stored in the memory 138. Alternatively or
in addition, the control module 136 can comprise hardwired digital
circuitry and/or analog circuitry. The DEP module 142, the EW
module 144, and/or the other modules 140 can be similarly
configured. Thus, functions, processes, acts, actions, or steps of
a process discussed herein as being performed with respect to the
apparatus 100 can be performed by one or more of the master
controller 134, DEP module 142, EW module 144, or other modules 140
configured as discussed above.
[0039] As also shown in FIG. 1, an electrical biasing device 118
can be connected to the apparatus 100. The electrical biasing
device 118 can, for example, comprise one or more voltage or
current sources.
[0040] As can be seen in FIG. 1, each DEP configuration 122 of the
structure 104 can be part of a different DEP device 120 built into
the enclosure 102 for temporarily generating net DEP forces on
micro-objects (not shown in FIG. 1) in liquid medium (not shown in
FIG. 1) on the outer surface 124 of the DEP configuration 122.
Depending on such characteristics as the frequency of a biasing
device (e.g., 206 in FIG. 2) the dielectric properties of the
liquid medium (e.g., 222 in FIG. 2), and/or the micro-objects
(e.g., 224, 226), the DEP force can attract or repeal the nearby
micro-objects. Similarly, each EW configuration 126 of the
structure 104 can be part of a different EW device 130 built into
the enclosure 102 for temporarily changing a wetting property of
the electrowetting surface 128 or a region of the electrowetting
surface 128 of the EW configuration 126.
[0041] FIGS. 2A and 2B (which show partial, cross-sectional, side
views of the enclosure 102 of FIG. 1) illustrate an example of a
DEP device 120. The DEP device 120 in FIG. 1 and each DEP device
120 in any figure (e.g., FIG. 11) can be configured like the DEP
device 120 shown in FIGS. 2A and 2B or any variation thereof (e.g.,
as illustrated in FIG. 3 or 4).
[0042] As shown, a DEP device 120 can comprise a biasing electrode
202, a switchable element 212, and another biasing electrode 204
(which can be an example of a first electrode or a second
electrode). The biasing electrode 202 can be part of the cover 102,
and the switchable element 212 and the other biasing electrode 204
can be part of the structure 104. Alternatively, the biasing
electrode 202 can also be part of the structure 104. The chamber
112 can be between the biasing electrode 202 and the switchable
element 212, which can be located between the chamber 112 and the
other biasing electrode 204. The chamber 112 is illustrated in FIG.
2A containing a first liquid medium 222 in which micro-objects 224,
226 (two are shown but there can be more) are disposed. As shown,
the outer surface 124 can be an outer surface of the switchable
element 212. Alternatively, a layer of material (not shown) can be
disposed on the surface of the switchable element 212, and the
outer surface 124 of that layer of material can comprise the outer
surface 124. As noted, the outer surface 124 can be hydrophilic.
Regardless of whether the outer surface 124 is an outer surface of
the switching element itself 212 or the outer surface of a layer of
material (e.g., a coating) (not shown) disposed on the switching
element 212, the switching element 212 can be said to be disposed
between the outer surface 124 and the electrode 204.
[0043] A first power source 206 (which can be part of the biasing
device 118 of FIG. 1) can be connected to the electrodes 202, 204.
The first power source 206 can be, for example, an alternating
current (AC) voltage or current source. The first power source 206
can create a generally uniform electric field between the
electrodes 202, 204 and a weaker field in the chamber 112, which
can result in negligible DEP forces on each micro-object 224, 226
in the medium 222 on the outer surface 124 of the DEP configuration
122.
[0044] The impedance of the switchable element 212 can be greater
than the impedance of the medium 222 in the chamber 112 so that the
voltage drop due to the first power source 206 from the biasing
electrode 202 to the other biasing electrode 204 is greater across
the switchable element 212 than the voltage drop across the medium
222. As shown in FIG. 2B, the switchable element 212 can be
configured, however, to temporarily create a low impedance path 232
(e.g., an electrically conductive path) from a region 230 at or
adjacent to the outer surface 124 of the switchable element 212 to
the other biasing electrode 204. The impedance of the low impedance
path 232 can be less than the impedance of the medium 222. The
voltage drop due to the first power source 206 across the medium
222 from the biasing electrode 202 to the region 230 can now be
greater than the voltage drop from the region 230 through the low
impedance path 232 to the other biasing electrode 204 while the
voltage drop across the switchable element 212 otherwise generally
remains greater than the voltage drop across the medium 222. This
can alter the electric field in the medium 222 in the vicinity of
the region 230, which can create a net DEP force F on a nearby
micro-object 224. The force F, which as noted above can be
configured to alternatively attract or repel the nearby
micro-object 224, can be sufficient to move the micro-object 224 on
the outer surface 124. By sequentially activating and deactivating
multiple regions 230 on the surface 124, the micro-object 224 can
be moved along the surface 124. As will be discussed in more detail
with respect to FIG. 12A, the micro-object 224 can also be moved
from the outer surface 124 of one DEP configuration 122 to the
outer surface 124 of another DEP configuration 122.
[0045] In the example of the switchable element 212 shown in FIGS.
2A and 2B, the switchable element 212 can comprise a
photoconductive material that has a relatively high electrical
impedance except when directly illuminated with a beam of light
242. As shown, a narrow beam of light 242 directed onto a
relatively small region 230 on or adjacent to the outer surface 124
can significantly reduce the impedance of the illuminated portion
of the switchable element 212 thereby creating the low impedance
path 232. In such an embodiment of the switchable element 212, a
low impedance path 232 can be created from any region 230 at or
adjacent to any location on the surface 124 of the switchable
element 212 to the other biasing electrode 204 by directing a beam
of light 242 at the desired location. The light 242 can be directed
from the bottom as shown in FIG. 2B and/or from above (not shown)
and thus through the electrode 202 and first medium 222.
[0046] FIG. 3 illustrates another example 300 of the DEP device
120. That is, the example DEP device 300 of FIG. 3 can replace any
instance of the DEP device 120 in any of the figures.
[0047] As shown, rather than comprising a photoconductive material,
the switchable element 212 of the DEP device 120 of FIG. 3
comprises one or more (six are shown but there can be fewer or
more) switches 302 that can be temporarily activated to
electrically connect a fixed region 330 on or adjacent to the
surface 124 of the switching element 212 to the biasing electrode
204. Activating a switch 302 can thus create a low impedance path
(like path 232 in FIG. 2B) from a fixed region 330 on or adjacent
to the surface 124 of the switchable element 212 to the other
biasing electrode 204. Otherwise, the DEP device 120 can be like
the DEP device 120 of FIG. 2B and like numbered elements can be the
same.
[0048] In FIG. 3, multiple switches 302 are shown connecting
multiple relatively small regions 330 of the surface 124 to the
electrode 204. In such an embodiment, a low impedance electrical
path like path 232 in FIG. 2B can be temporarily created from any
of the regions 330 to the electrode 204 by activating the
corresponding switch 302. In such an embodiment, net DEP forces F
(see FIG. 2B) can be selectively created with respect to the
individual regions 330. Alternatively, there can be one switch 302
connecting the surface 124 to the electrode 204. In such an
embodiment, the surface 124 is one region 330, and activating the
switch 302 can temporarily create a net DEP force with respect to
essentially the entire surface 124.
[0049] Each switch 302 can include a control 304 for activating
(e.g., closing) and deactivating (e.g., opening) the switch 302.
The switches 302 can be controlled in any manner. For example, the
switches 302 can be controlled by the presence or absence of a beam
of light on the control 304. As another example, the switches 302
can be toggled by directing a beam of light onto the control 304.
As yet another example, the switches 302 can be electronically
controlled rather than light controlled. The switches 302 can thus
alternatively be controlled by providing control signals to the
controls 304.
[0050] FIG. 4 illustrates an example configuration of the switches
302 of FIG. 3. In the example illustrated in FIG. 4, the switchable
element 212 can comprise a semiconductor material, and each switch
302 can be a transistor 410 integrated into the semiconductor
material of the switching element 212. For example, as shown, each
transistor 410 can comprise a first region 402 at the outer surface
124, a second region 406 in contact with the biasing electrode 204,
and a control region 404. The transistor 410 can be configured so
that the first region 402 is electrically connected to the second
region 406 to create a low impedance path (like the path 232 in
FIG. 2B) from a fixed region 330 of the surface 124 to the biasing
electrode 204 only when the control region 404 is activated.
[0051] In some embodiments, each transistor 410 can be activated
and deactivated by beams of light. For example, each transistor 410
can be a phototransistor whose control region 404 is activated or
deactivated by the presence or absence of a beam of light.
Alternatively, the control region 404 of each transistor can be
hardwired and thus activated and deactivated electronically.
[0052] The transistors 410 can be any type of transistor including
bipolar transistors (BJTO) or field effect (FET) transistors. The
body of the switching element 212 and thus the second region 406 of
each transistor 410 can be doped with a first type of dopant (e.g.,
an n or p type dopant), and the first region 402 can also be doped
with the first type of dopant. The control region 404, however, can
be doped with a second type of dopant (e.g., the other of a p or an
n type dopant). The first region 402 of each transistor 410 can be
configured to be a source or a sink of holes, and the body of the
switching element 212 and thus the second region 406 of each
transistor 410 can be configured to be the other of a sink or
source for holes. Thus, for example, if the transistors 410 are
bipolar transistors, the first regions 402 can be emitters or
collectors, the second regions 406 can be the other of collectors
or emitters, and the control regions 404 can be bases of the
transistors 410. As another example, if the transistors 410 are FET
type transistors, the first regions 402 can be sources or drains,
the second regions 406 can be the other of drains or sources, and
the control regions 404 can be gates of the transistors 410.
[0053] As also shown in FIG. 4, isolation barriers 408 can be
disposed in the switching element 212 between the transistors 410.
The isolation barriers 408 can comprise, for example, trenches in
the switching element 212, and the trenches can be filled with a
switchable element.
[0054] The DEP devices 120, 300 illustrated in FIGS. 2A-4 are but
examples of possible configurations of the DEP devices 120 in the
apparatus 100. Generally speaking, the DEP devices 120 can be
optoelectronic tweezers (OET) devices examples of which are
disclosed in U.S. Pat. No. 7,612,355 or U.S. patent application
Ser. No. 14/051,004. Other examples of the DEP devices 120 include
electronically controlled electrodes.
[0055] FIGS. 5A and 5B (which show partial, cross-sectional, side
views of the enclosure 102 of FIG. 1) illustrate an example of an
EW device 130. Each EW device 130 in FIG. 1 (or any other figure
(e.g., FIG. 11)) can be configured like the EW device 130 shown in
FIGS. 5A and 5B or any variation thereof (e.g., as illustrated in
FIG. 6).
[0056] As shown, an EW device 130 can comprise a biasing electrode
502, a dielectric material 514, a switchable element 512, and
another biasing electrode 504 (which can be an example of a first
or a second electrode). The biasing electrode 502 can be part of
the cover 102, and the dielectric material 514, the switchable
element 512, and the other biasing electrode 504 can be part of the
structure 104. Alternatively, the biasing electrode 502 can also be
part of the structure 104. The chamber 112 can be between the
biasing electrode 502 and the dielectric material 514, and the
switchable element 512 can be disposed between the dielectric
material 514 and the biasing electrode 504. The chamber 112 is
illustrated in FIG. 5A containing a droplet 524 of a second liquid
medium in a third liquid medium 522. The first liquid medium 222
(see FIG. 2A), the second liquid medium, and the third liquid
medium 522 can be any of many types of media. For example, the
second medium of the droplet 524 can be a medium that is immiscible
in the third medium 522. Thus, for example, the second medium of
the droplet 524 can comprise an aqueous medium, and the third
medium 522 can comprise an oil based medium. (Examples of suitable
oils include gas permeable oils such as fluorinated oils.
Fluorocarbon based oils are also examples of suitable oils.) As
another example, the first medium 222 and the second medium of the
droplet 524 can be the same type of medium.
[0057] Although shown as an outer surface of the dielectric
material 514 itself, the electrowetting surface 128 can instead be
an outer surface of a material (e.g., a coating) (not shown)
disposed on the dielectric material 514. Regardless, the dielectric
material 514 can be said to be between the electrowetting surface
128 and the switching element 512.
[0058] As shown, a second power source 506 (which can be part of
the biasing device 118 of FIG. 1) can be connected to the
electrodes 502, 504. The second power source 506 can be, for
example, an alternating current (AC) voltage or current source. The
second power source 506 can create a generally uniform electric
field between the electrodes 502, 504, which can result in a
negligible change of a contact angle of the droplet 524 on the
electrowetting surface 128 of the EW configuration 126 and thus a
negligible change in a wetting property of the electrowetting
surface 128.
[0059] The impedance of the switchable element 512 can be greater
than the impedance of the dielectric material 514 so that the
voltage drop due to the second power source 506 from the biasing
electrode 502 to the other biasing electrode 504 is greater across
the switchable element 512 than the voltage drop across the
dielectric material 514. As shown in FIG. 5B, the switchable
element 512 can be configured, however, to temporarily create a low
impedance path 532 (e.g., an electrically conductive path) from a
region 528 at an interface between the switchable element 512 and
the dielectric material 514 to the other biasing electrode 504. The
impedance of the low impedance path 532 can be less than the
impedance of the dielectric material 514. The voltage drop due to
the second power source 506 across the dielectric material 514 can
now be greater than the voltage drop from the region 528 through
the low impedance path 532 to the other biasing electrode 504 while
the voltage drop across other portions of the switchable element
512 remains greater than the voltage drop across the dielectric
material 514. This can alter the electric field between the
electrodes 502, 504 in the vicinity of the region 528, which can
change the wetting property of the electrowetting surface 128 at a
region 530 of the surface 128 adjacent to the region 528. For
example, the foregoing can increase the wetting property of the
electrowetting surface 128 at the region 530, which can cause the
droplet 524 to move M to the region 530. As noted, the
electrowetting surface 128 can be hydrophobic, but creating the low
impedance path 532 can temporarily make the surface 128 at the
region 530 less hydrophobic or even hydrophilic. By sequentially
activating and deactivating regions 530 along the electrowetting
surface 128, the droplet 524 can be moved along the electrowetting
surface 128. As will be discussed in more detail with respect to
FIGS. 12A-12C, the droplet 524 can also be moved from the
electrowetting surface 128 of one EW device 130 to the
electrowetting surface 128 of another EW device 130.
[0060] The switchable element 512 can be configured in any of the
ways the switchable element 212 of FIGS. 2A and 2B can be
configured. For example, the switchable element 512 shown in FIGS.
5A and 5B can comprise a photoconductive material that has a
relatively high electrical impedance except when illuminated with a
direct beam of light 542. As shown, a narrow beam of light 542
directed onto the region 528 can significantly reduced the
impedance of the illuminated portion of the switchable element 512
thereby creating the low impedance path 532. In such an embodiment
of the switchable element 512, a low impedance path 532 can be
created from any region 528 anywhere at the interface between the
switchable element 512 and the dielectric material 514 to the
second electrode 504 by directing a beam of light 542 onto the
region 528. The wetting property of a corresponding region 530 on
the electrowetting surface 128 can thus be changed anywhere on the
electrowetting surface 128.
[0061] FIG. 6 illustrates another example 600 of the EW device 130.
That is, the example EW device 600 of FIG. 6 can replace any
instance of the EW device 130 in any of the figures.
[0062] As shown, rather than comprising a photoconductive material,
the switchable element 512 of the EW device 600 of FIG. 6 can
comprise one or more (six are shown but there can be fewer or more)
switches 602 that can be temporarily activated to electrically
connect a fixed region 628 at the interface between the switchable
element 512 and the dielectric material 514 to the biasing
electrode 504. Activating a switch 602 can thus create a low
impedance path (like path 532 in FIG. 5B) from a fixed region 528
at the interface between the switchable element 512 and the
dielectric material 514 to the biasing electrode 504, which can
change the wetting property at a corresponding fixed region 630 on
the electrowetting surface 128. Otherwise, the EW device 600 can be
like the EW device 130 of FIG. 5B and like numbered elements can be
the same. Each of the switches 602 in the switchable element 512
can be configured, for example, as transistors generally like the
transistors 410 illustrated in FIG. 4 and discussed above.
[0063] In FIG. 6, multiple switches 602 are shown connecting
multiple relatively small regions 628 of the interface of the
switchable element 512 to the dielectric material 514
(corresponding to multiple relatively small fixed regions 630 at or
adjacent to the electrowetting surface 128) to the electrode 504.
In such an embodiment, a wetting property of any of the regions 630
on the electrowetting surface 128 can be temporarily changed by
activating a corresponding switch 602. Alternatively, there can be
one switch 602 connecting the interface of the switchable element
512 to the dielectric material 514 to the electrode 504. In such an
embodiment, the electrowetting surface 128 is one region 630, and
activating the switch 602 can temporarily change a wetting property
of essentially the entire electrowetting surface 128.
[0064] The EW devices 130, 600 illustrated in FIGS. 5A-6 are but
examples of possible configurations of the EW devices 130 in the
apparatus 100. Generally speaking, the EW devices 130 can be
optoelectronic wetting (OEW) devices examples of which are
disclosed in U.S. Pat. No. 6,958,132. Other examples of the EW
devices 130 include electrowetting on dielectric (EWOD) devices,
which can be electronically controlled.
[0065] The structure 104 of FIG. 1 can be physically configured to
comprise one or more DEP configurations 122 and one or more EW
configurations 126 in any of a variety of ways. FIGS. 7-9
illustrate examples.
[0066] In the example shown in FIG. 7, multiple DEP configurations
122 and multiple EW configurations 126 can be integrated into a
single monolithic component 702. As shown, the structure 104 can
comprise a monolithic component 702, and the DEP configurations 122
and EW configurations 126 can comprise sections 704-710 of the
monolithic component 702. The monolithic component 702 can comprise
a semiconductor material.
[0067] For example, as shown, a first EW configuration 126a can
comprise a dielectric material 514 disposed on one side of a first
section 704 of the monolithic component 702 and an electrode 504 on
the other side of the first section 704, which can be configured
like switchable element 512 illustrated in FIGS. 5A-6. For example,
the first section 704 can comprise photoconductive material
generally like the switchable element 512 shown in FIG. 5B. As
another example, the first section 704 can comprise one or more
switches like the switches 602 in FIG. 6, which can be configured
as transistors like the transistors 410 of FIG. 4 as discussed
above. A second EW configuration 126b can similarly comprise
another dielectric material 514 disposed on one side of a third
section 708 of the monolithic component 702 and another electrode
504 on the other side of the third section 708, which can be
configured like the switchable element 512 illustrated in any of
FIGS. 5A-6.
[0068] A first DEP configuration 122a can comprise a second section
706 of the monolithic component 702 and an electrode 204 disposed
adjacent to the second section 706, which can be configured like
the switchable element 212 illustrated in FIGS. 2A-4. For example,
the second section 706 can comprise photoconductive material
generally like the switchable element 212 shown in FIG. 2B. As
another example, the second section 706 can comprise one or more
switches like the switches 302 in FIG. 3, which can be configured
as transistors like the transistors 410 of FIG. 4. A second DEP
configuration 122b can similarly comprise a fourth section 710 of
the monolithic component 702 and another electrode 204 disposed
adjacent to the fourth section 710, which can be configured like
the switchable element 212 illustrated in any of FIGS. 2A-4.
[0069] In the example shown in FIG. 8, the DEP configurations 122
and the EW configurations 126 can comprise distinct structures. For
example, as shown, a first EW configuration 126a can be a distinct
structure that comprises a dielectric material 514 disposed on one
side of a first EW configuration switching element 804 and an
electrode 504 on the other side of the switching element 804. The
switching element 804 can comprise, for example, semiconductor
material, a printed circuit board, or the like. The switching
element 804 can be configured like switchable element 512
illustrated in any of FIGS. 5A-6. For example, the switching
element 804 can comprise photoconductive material generally like
the switchable element 512 shown in FIG. 5B. As another example,
the switching element 804 can comprise one or more switches like
the switches 602 in FIG. 6, which can be configured as transistors
like the transistors 410 of FIG. 4 as discussed above. A second EW
configuration 126b can also be a distinct structure that comprises
another dielectric material 514 disposed on one side of a second EW
configuration switching element 808 and another electrode 504 on
the other side of the switching element 808. The switching element
808 can be the same as or similar to the switching element 804 as
discussed above.
[0070] A first DEP configuration 122a can be a distinct structure
that comprises a first DEP configuration switching element 806 and
an electrode 204. The switching element 806 can comprise, for
example, semiconductor material, a printed circuit board, or the
like. The switching element 806 can be configured like the
switchable element 212 illustrated in any of FIGS. 2A-4. For
example, the switching element 806 can comprise photoconductive
material generally like the configuration of the switchable element
212 shown in FIG. 2B. As another example, the switching element 806
can comprise one or more switches like the switches 302 in FIG. 3,
which can be configured as transistors like the transistors 410 of
FIG. 4 as discussed above. A second DEP configuration 122b can also
be a distinct structure that comprises a second DEP configuration
switching element 810 and another electrode 204. The switching
element 810 can be like the switching element 806 as discussed
above.
[0071] As shown in FIG. 8, the EW configurations 126a, 126b and the
DEP configurations 122a, 122b can be disposed on a master structure
814. The EW configurations 126a, 126b and the DEP configurations
122a, 122b can be arranged in any pattern on the master structure
814. For example, the EW configurations 126a, 126b and the DEP
configurations 122a, 122b can be disposed side by side and spaced
apart by spacers 812 as illustrated. As another example, in some
embodiments, there are no spacers 812, and adjacent to EW
configurations 126a, 126b and DEP configurations 122a, 122b can be
abutted against each other.
[0072] Some embodiments do not include a master structure 814. For
example, in some embodiments, there is not a master structure 814,
but the EW configurations 126a, 126b and the DEP configurations
122a, 122b are adhered one to another. For example, the spacers 812
illustrated in FIG. 8 can be an adhesive that adheres sides of
adjacent to EW configurations 126a, 126b and DEP configurations
122a, 122b to each other.
[0073] Although not shown, provisions can be provided for
connecting power supplies (e.g., 206 and 506 in FIGS. 2A and 5A) to
the electrodes 204, 504. For example, the master structure 814 can
comprise one or more electrically conductive connectors (not shown)
to the electrodes 204 and one or more electrically conductive
connectors (not shown) to the electrodes 504. Examples of such
connectors include electrically conductive vias (not shown) through
the master structure 814.
[0074] Regardless, the EW configurations 126a, 126b and the DEP
configurations 122a, 122b can be positioned so that the
electrowetting surfaces 128 of the EW configurations 126a, 126b and
the outer surfaces 124 of the DEP configurations 122a, 122b are
substantially parallel and/or substantially in a same plane. The
electrowetting surfaces 128 and the outer surfaces 124 can thus
form the boundary 106 of the structure 104. The boundary 106 can
thus be a composite surface comprising multiple outer surfaces 124
of multiple DEP configurations 122 and multiple electrowetting
surfaces 128 of multiple EW configurations 126.
[0075] In the example shown in FIG. 9, the DEP configurations 122
can comprise sections of a master switching element 902, and the EW
configurations 126 can comprise stand alone, distinct structures
disposed in cavities 916, 918 in the master switching element
902.
[0076] As shown, a first EW configuration 126a can be a stand
alone, distinct structure that comprises a dielectric material 514
disposed on one side of a first EW configuration switching element
904 and an electrode 504 on the other side of the switching element
904. The switching element 904 can comprise, for example,
semiconductor material. The switching element 904 can be configured
like switchable element 512 illustrated in any of FIGS. 5A-6. For
example, the switching element 904 can comprise photoconductive
material generally like the switchable element 512 shown in FIG.
5B. As another example, the switching element 904 can comprise one
or more switches like the switches 602 in FIG. 6, which can be
configured as transistors like the transistors 410 of FIG. 4 as
discussed above. A second EW configuration 126b can also be a stand
alone, distinct structure that comprises another dielectric
material 514 disposed on one side of a second EW configuration
switching element 908 and another electrode 504 on the other side
of the switching element 908. The switching element 908 can
comprise, for example, semiconductor material, which can be
configured like the switching element 904 as discussed above. The
EW configurations 126a, 126b can be disposed in cavities 916, 918
in the master switching element 902.
[0077] A first DEP configuration 122a can comprise a first section
906 of the master switching element 902 and an electrode 204
disposed adjacent to the first section 906, which can be configured
like the switchable element 212 illustrated in any of FIGS. 2A-4.
For example, the first section 906 can comprise photoconductive
material generally like the switchable element 212 shown in FIG.
2B. As another example, the first section 906 can comprise one or
more switches like the switches 302 in FIG. 3, which can be
configured as transistors like the transistors 410 of FIG. 4. A
second DEP configuration 122b can similarly comprise a second
section 910 of the master switching element 902 and another
electrode 204 disposed adjacent to the second section 910, which
can be configured like the switchable element 212 illustrated in
FIGS. 2A-4.
[0078] As shown, the sections 906, 910 of the master switching
element 902 that correspond to the DEP configurations 122a, 122b
can be disposed between the cavities 916, 918 in which the EW
configurations 126a, 126b are disposed. The cavities 916, 918 and
the EW configurations 126a, 126b can be sized and positioned such
that the outer surfaces 124 of the DEP configurations 122a, 122b
and the electrowetting surfaces 128 of the EW configurations 126a,
126b and are substantially parallel and/or substantially in a same
plane. The outer surfaces 124 and the electrowetting surfaces 128
can thus form the boundary 106 of the structure 104.
[0079] In the example shown in FIG. 9, the DEP configurations 122
comprise sections 906, 910 of a master switching element 902, and
the EW configurations 126 are stand alone, distinct structures
disposed in cavities 916, 918 in a master switching element 902.
Alternatively, the EW configurations 126 can comprise sections
(e.g., like sections 906, 910) of the master switching element 902,
and the DEP configurations 122 can be stand alone, distinct
structures (e.g., like the EW configurations 126 shown in FIG. 9)
disposed in cavities 916, 918 of the master switching element
902.
[0080] In any of the embodiments illustrated in FIGS. 7-9, the
first power source 206 can be connected to each of the electrodes
204 and corresponding electrodes 202 (not shown in FIGS. 7-9)
generally as shown in FIGS. 2A-3. All of the electrodes 204 in
FIGS. 7 and 8 can, for example, be electrically connected to each
other. Similarly, the second power source 406 can be connected to
the electrodes 504 and corresponding electrodes 502 (not shown in
FIGS. 7 and 8) in the embodiments of FIGS. 7 and 8. The embodiment
of FIG. 9 can also facilitate connecting the second power source
506 to the electrodes 504 of the EW configurations 126. For
example, as shown in FIG. 9, the second power source 506 can
connect to electrodes 914, which are connected (e.g., by electrical
connections 912 such as vias, electrically conductive adhesive, or
the like) to the electrodes 504 of the EW configurations 126.
[0081] FIG. 10 illustrates an example of the structure 104
comprising the switchable element 212 configured somewhat as shown
in FIG. 3, and like numbered elements in FIGS. 3 and 10 can be the
same. As shown, the switching element 212 can comprise multiple DEP
configurations 122 and multiple EW configurations 126. Each of the
DEP configurations 122 can comprise a hydrophilic layer 1002
comprising the outer surface 124, which can thus be hydrophilic; an
electrode 204; and a switch 302 for selectively creating a low
impedance path (e.g., like path 232 in FIG. 2B) through the
switchable element 212 to the electrode 204 as discussed above.
[0082] As also shown, the switching element 212 can also include
isolation barriers 408 between the DEP configurations 122, which
can be part of the EW configurations 126. For example, each EW
configuration 126 can comprise a dielectric material 514 comprising
an electrowetting surface 128, photoconductive material disposed in
one of the isolation barriers 408, and an electrode 504. As shown,
an electrical connector 1004 (e.g., a via) can electrically connect
the photoconductive material in an isolation barrier 408 to a
corresponding electrode 504. Light directed onto the
photoconductive material in one of the isolation barriers 408 can
create a low impedance path (like path 532 in FIG. 5B) through the
photoconductive material in the illuminated barrier 408 to the
electrode 504 and thereby change a wetting property of the
electrowetting surface 128 of the EW configuration 126 generally as
discussed above with respect to FIG. 5B.
[0083] The apparatus 100 of FIG. 1, including any variation
discussed above or illustrated in FIGS. 2A-10, is an example only.
FIG. 11 illustrates another example configuration of the apparatus
100.
[0084] The apparatus 100' of FIG. 11 can be generally similar to
the apparatus 100 of FIG. 1, and like numbered elements can be the
same. As shown, however, the structure 104' in FIG. 11 comprises
multiple DEP devices 120 (each corresponding to one of the
illustrated DEP configurations 122) and multiple EW devices 130
(each corresponding to one of the EW configurations 126). Some or
all of the DEP devices 120 and EW devices 130 can be positioned
such that the outer surfaces 124 of the DEP configurations 122 and
the electrowetting surfaces 128 of the EW configurations 126 of the
structure 104' are disposed in an alternating pattern. For example,
all or one or more portions of the pattern of DEP devices 120 and
EW devices 130 can be such that rows and columns of the pattern
comprise alternating outer surfaces 124 and electrowetting surfaces
128 generally as shown in FIG. 11.
[0085] FIGS. 12A-12C show partial, cross-sectional, side views of
the enclosure 102 of the apparatus 100' of FIG. 11 and also
illustrates an example of operation of the apparatus 100'.
[0086] As shown in FIG. 12A, each DEP device 120 can comprise an
electrode 202 that can be part of the cover 110. In FIG. 12A, the
cover 110 is illustrated as also comprising a support structure
1202 for the electrodes 202. Each DEP device 120 can also comprise
a switchable element 212 and another electrode 204 generally as
discussed above with respect to FIG. 2A. Each DEP device 120 can
also include a hydrophilic material 1002 that comprises the outer
surface 124, which can thus be hydrophilic. Otherwise, each DEP
device 120 can be configured and operate in any manner disclosed
herein including the examples shown in FIGS. 2A-4. The first power
source 206 can be connected to the biasing electrodes 202 and 204.
In some embodiments, the biasing electrodes 202 on support 1202 can
be interconnected with each other, and the biasing electrodes 204
on the switching element 1204 can similarly be interconnected with
each other.
[0087] Each EW device 130 can comprise an electrode 502 that can be
part of the cover 110 as shown. Each EW device 130 can also
comprise a dielectric material 514, switchable element 512, and
another electrode 504 generally as discussed above with respect to
FIG. 5A. The second power source 506 can be connected to the
biasing electrodes 502 and 504. In some embodiments, the biasing
electrodes 502 on support 1202 can be interconnected with each
other, and the biasing electrodes 504 on the switching element 1204
can similarly be interconnected with each other. Each EW device 130
can be configured and operate in any manner disclosed herein
including the examples shown in FIGS. 5A-6.
[0088] Examples of operation of the apparatus 100' are illustrated
in FIGS. 12A-12C and FIGS. 14A-14C.
[0089] As shown in FIG. 12A, a micro-object 224 initially disposed
on an outer surface 124a of a first DEP device 120a can be moved to
the outer surface 124b of a nearby DEP device 120b (e.g., a second
DEP device) by activating the nearby DEP device 120b generally as
described above (e.g., creating an electrically conductive path
like path 232 in FIG. 2B through the switchable element 212b of the
nearby DEP configuration 122b) without also activating the first
DEP device 120a. As discussed above, the foregoing can create a net
DEP force on the micro-object 224 sufficient to move the
micro-object 224 from the outer surface 124a of the first DEP
device 120a to the outer surface 124b of the nearby DEP device
120b). As shown, the micro-object 224 can be moved from the outer
surface 124a across an intervening electrowetting surface 128b of
an adjacent EW device 130b. As also shown, the micro-object 224 can
be moved while inside a droplet 524 of the first medium 222, which
can be disposed in the second medium 522.
[0090] As also illustrated in FIGS. 12A-12C, a droplet 524 can be
moved on the structural boundary 106. For example, as shown in
FIGS. 12A-12C, a droplet 524, initially disposed in a first
location (e.g., on outer surfaces 124a, 124b of DEP devices 120a,
120b and an electrowetting surface 128b of a first EW device 128b
in the example shown in FIG. 12A), can be moved to a second
location by activating a nearby EW device 130c generally as
described above (e.g., creating an electrically conductive path
like path 532 in FIG. 5B through the switchable element 512a of the
nearby EW device 130b) and thereby decreasing the hydrophobicity of
the electrowetting surface 128c of the nearby EW device 130c
sufficiently to draw an edge of the droplet 524 across the
electrowetting surface 128c to the outer surface 124c of a DEP
device 120c near the EW device 130c as illustrated in FIG. 12B. The
foregoing can be done without also activating the electrowetting
surface 128b. The droplet 524 can thus be moved from a first
position on the surfaces 124a, 128b, 124b shown in FIG. 12A to a
second position on the surfaces 124b, 128a, 124c as shown in FIG.
12C. As illustrated in FIG. 12B, liquid pressure P (e.g., applied
through an inlet 114 or by a pressure device (not shown) in the
chamber 112) can aide in moving M the droplet 524. As also shown in
FIGS. 12B and 12C, the micro-object 224 can move with the droplet
524 without activating any of the DEP devices 122. Droplets like
droplet 524, however, can be moved whether or not the droplet 524
contains one or more micro-objects like micro-object 224.
[0091] Although not shown in FIGS. 12A-12C, the foregoing
operations of moving a micro-object 224 and a droplet 524 can be
performed simultaneously in the apparatus 100' of FIGS. 11 and
12A-12C. For example, a micro-objet 224 can be moved in one droplet
524 as illustrated in FIG. 12A while another droplet (not shown in
FIGS. 12A-12C but can be like droplet 524) can be moved generally
in the same way that the droplet 524 is moved in FIGS. 12A-12C.
[0092] FIG. 13 shows an example of a process 1300 by which the
apparatus 100' of FIG. 11 can be operated generally in accordance
with the examples shown in FIGS. 12A-12C. As shown at step 1302,
the process 1300 can move a micro-object from one DEP device to
Another by Selectively activating and deactivating as needed one or
more DEP devices, which can be performed generally as discussed
above (e.g., as illustrated in FIG. 12A). At step 1304, the process
1300 can move a droplet from a first location to a second location,
which can also be performed generally as discussed above (e.g., as
shown in FIGS. 12A-12C). Indeed, the process 1300 can be performed
in accordance with the examples illustrated in FIGS. 12A-12C
including any variation or additional steps or processing discussed
above with respect to FIGS. 12A-12C.
[0093] FIGS. 14A-14C illustrate another example of an operation of
the microfluidic device 100' of FIG. 11. FIGS. 14A-14C show a top
view of the apparatus 100' with its cover 110 removed. Biasing
devices 206, 506 are not shown but can be connected to the
apparatus 100' generally as shown in FIGS. 12A-12C.
[0094] In the example shown in FIG. 14A, a droplet 524 of the first
medium 222 is disposed in the second medium 522 in the chamber 112,
and micro-objects 224 can be disposed inside the droplet 524. As
shown in FIG. 14B, one or more of the micro-objects 224 in the
droplet 524 can be moved into or out of a selected sub-region 1402
of the droplet 524 until there is a selected group 1404 of the
micro-objects in the sub-region 1402 of the droplet 524. As shown
in FIG. 14C, the sub-region 1402 of the droplet 524 can be moved
away and thus separate from the droplet 524 forming a new droplet
1406 that contains the selected group 1404 of micro-objects 224.
The micro-objects 224 can be moved (as shown in FIG. 14B) generally
as discussed above (e.g., from the outer surface 124 of one DEP
device 120 (not shown in FIGS. 14A-14C) to the outer surface 124 of
a nearby DEP device 120 (not shown in FIGS. 14A-14C), and the
sub-region 1404 can be moved and thus pulled away and separated
from the droplet 524 to form a new droplet 1406 generally as
discussed above (e.g., by selectively changing a wetting property
of ones of the electrowetting surfaces 128 of adjacent ones of the
EW devices 130 (not shown in FIGS. 14A-14C).
[0095] For example, the sub-region 1402 of the droplet 524 can
initially be disposed in a first location 1418 in the chamber 112
as shown in FIG. 14B. The location 1418 can include first outer
surfaces 124 of a first set of the DEP devices 122 and first
electrowetting surfaces 128 of a first set of the EW devices 130 on
which the sub-region 1402 is initially disposed as shown in FIG.
14B. Generally in accordance with the discussion above of moving
droplets, the sub-region 1402 can be separated from the droplet
524, forming a new droplet 1406, by moving the sub-region 1402 of
the droplet to a second location 1420 as shown in FIG. 14C. The
second location 1420 can include second outer surfaces 124 of a
second set of the DEP devices 122 and second electrowetting
surfaces 128 of a second set of the EW devices 130. The sub-region
1402 can be moved from the first location 1418 to the second
location 1420 by, for example, sequentially activating one or more
(one is shown but there can be more) of the EW devices 130 in a
third location 1422. (The EW devices 130 in the third location 1422
can be an example of a third set of the EW devices 130 and their
electrowetting surfaces 128 can be an example of third
electrowetting surfaces.) This can be done, for example, without
also activating EW devices 130 on whose electrowetting surfaces 128
all of the droplet 524 except for the sub-region 1402 is disposed.
Generally as discussed above, this can move the sub-region 1402 of
the droplet 524 over the third location 1422. Thereafter, the EW
devices 128 in the third location 1422 can be deactivated, and one
or more of the EW devices 130 in the second location can be
activated, which generally as discussed above, can further move the
sub-region 1402 (now a new droplet 1406) to the second location
1420 shown in FIG. 14C.
[0096] A new droplet 1406 can be created from an existing droplet
524 as illustrated in FIGS. 14A-14C regardless of whether there are
any micro-objects 224 in the existing droplet 524 or the new
droplet 1406. Moreover, more than one new droplet (not shown but
can be like new droplet 1406) can be created from the existing
droplet 524.
[0097] FIG. 15 illustrates an example of a process 1500 by which
the apparatus 100' of FIG. 11 can be operated generally in
accordance with the examples shown in FIGS. 14A-14C. As shown at
step 1502, the process 1500 can dispose a selected group of
micro-objects in a sub-region of a droplet, which can be performed
generally as discussed above (e.g., as illustrated in FIGS. 14A and
14B). At step 1504, the process 1500 can move the sub-region of the
droplet away from the droplet, separating the sub-region from the
droplet and thereby forming a new droplet, which can also be
performed generally as discussed above (e.g., as shown in FIG.
14C). Indeed, the process 1500 can be performed in accordance with
any of the examples illustrated in FIGS. 14A-14C including any
variation or additional steps or processing discussed above with
respect to FIGS. 14A-14C.
[0098] 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.
* * * * *