Microfluidic devices with flexible optically transparent electrodes

Patent metadata

Field	Value
Publication number	US-2016151784-A1
Application number	US-201514957075-A
Country	US
Kind code	A1
Filing date	Dec 2, 2015
Priority date	Jun 3, 2011
Publication date	Jun 2, 2016
Grant date	—

Abstract

Microfluidic devices in which electrokinetic mechanisms move droplets of a liquid or particles in a liquid are described. The devices include at least one electrode that is optically transparent and/or flexible.

First claim

1 - 28 . (canceled)

29 . An electrokinetic microfluidic device, comprising:
(a) a bottom channel configured to hold a liquid, comprising:
(i) a first wall comprising a transparent flexible mesh electrode; and
(ii) a second wall opposite said first wall comprising an electrode;
(iii) wherein said first wall defines an upper surface and said second wall defines a lower surface of at least a portion of said bottom channel; and
(b) a top channel overlying at least a region of said bottom channel, wherein said top channel is formed within a flexible material; and (c) wherein a membrane valve is formed at said region where said top channel and said bottom channel overlap.

30 . The device of claim 29 , wherein said device is a dielectrophoresis (DEP) device.

31 . The device of claim 30 , wherein said second wall comprises an array of fixed electrodes.

32 . The device of claim 29 , wherein said second wall of said bottom channel comprises a photoconductive layer.

33 . The device of claim 32 , wherein said device is an optoelectronic tweezers (OET) device.

34 . The device of claim 29 , wherein said photoconductive layer of said second wall of said bottom channel comprises a hydrophobic coating on said lower surface of said portion of said bottom channel.

35 . The device of claim 34 , wherein said device is an optoelectronic wetting (OEW) device.

36 . The device of claim 29 , wherein said flexible material forming said top channel is transparent.

37 . The device of claim 36 , wherein said flexible material is a polymer or silicone.

38 . The device of claim 37 , wherein said flexible material is polydimethylsiloxane (PDMS).

39 . The device of claim 29 , wherein said transparent flexible mesh electrode is a thin film.

40 . The device of claim 29 , wherein said transparent flexible mesh electrode comprises nanoparticles.

41 . The device of claim 40 , wherein said nanoparticles comprise nanotubes or nanowires.

42 . The device of claim 29 , wherein said transparent flexible mesh electrode comprises clusters of nanoparticles.

43 . The device of claim 29 , further comprising a biasing voltage source disposed between said transparent flexible mesh electrode and said second wall.

44 . A method of manipulating a droplet of a liquid or particles in a liquid in a microfluidic device, comprising the steps of:
(a) introducing a liquid or particles in a liquid to a bottom channel of said microfluidic device; (b) applying an electrokinetic force to said liquid or said particles in said liquid in said bottom channel; and (c) closing a membrane valve formed at a region of overlap between said bottom channel and a top channel.

45 . The method of claim 44 , wherein said step of applying said electrokinetic force comprises applying a biasing voltage between a transparent flexible mesh electrode embedded in a first wall defining an upper surface of said channel and an electrode in said second wall defining a lower surface of said channel.

46 . The method of claim 45 , wherein said step of applying said electrokinetic force further comprises projecting light onto a photoconductive layer of said second wall, thereby inducing a dielectrophoresis force upon said particles in said liquid in said bottom channel.

47 . The method of claim 45 , wherein said step of applying said electrokinetic force further comprises projecting light onto a photoconductive layer of said second wall, thereby inducing an electrowetting force upon said liquid in said bottom channel.

48 . The method of claim 45 , wherein said step of closing said membrane valve comprises applying pressure to said top channel, thereby expanding said top channel and deforming said first wall of said bottom channel.

49 . The method of claim 44 , further comprising a step of detecting said particles in said liquid in said bottom channel.

50 . The method of claim 49 wherein said step of detecting said particles comprises observing fluorescence from said particles in said liquid.

51 . The method of claim 49 , wherein said step of detecting said particles is performed by observing said particles through said transparent mesh flexible electrode imbedded in said first wall of said bottom channel.

52 . The method of claim 44 , wherein said step of closing said membrane valve stops fluid flow in said bottom channel.

53 . A method of moving particles in a liquid in a microfluidic device, comprising the steps of:
(a) introducing particles in a liquid to a bottom channel of said microfluidic device, wherein said microfluidic device comprises:
a first wall comprising a transparent flexible mesh electrode and a second wall opposite said first wall comprises an electrode, wherein said first wall defines an upper surface and said second wall defines a lower surface of at least a portion of said bottom channel; and
(ii) a first top channel, a second top channel, and a third top channel overlying a respective first region, a second region, and a third region of said bottom channel, wherein said first, second, and third top channels are formed within a flexible material, and further wherein a first membrane valve, a second membrane valve, and a third membrane valve are formed at said respective first, second and third regions; and
(b) applying pressure consecutively to said first, second, and third membrane valves, thereby moving said particles in said liquid in said bottom channel.

54 . The method of claim 53 , further comprising a step of applying an electrokinetic force to said particles in said liquid in said channel.

55 . The method of claim 54 , wherein said electrokinetic force is a dielectrophoretic force or an electrowetting force.

56 . The method of claim 54 , further comprising a step of detecting said particles in said bottom channel by observing said particles through said transparent flexible mesh electrode.

57 . The method of claim 56 , wherein said step of detecting said particles comprises observing fluorescence from said particles in said liquid.

Assignees

• Univ California

Inventors

• Chiou Pei-Yu E
• Huang Kuo-Wei
• Khandros Igor Y
• Wu Ming C

Classifications

• B01L2400/0424

  Dielectrophoretic forces · CPC title

• B03C2201/26

  for use in medical or biological applications · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• B03C5/005 Primary

  Dielectrophoresis, i.e. dielectric particles migrating towards the region of highest field strength · CPC title

• B01L2400/0427

  Electrowetting · CPC title