MICRODEVICE FOR TREATING LIQUID SPECIMENS

• US 20100320088A1
• Filed: 12/03/2007
• Published: 12/23/2010
• Est. Priority Date: 12/05/2006
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation), Centre National De La Recherche Scientifique
• Original Assignee: Centre National De La Recherche Scientifique, Energies Alternatives Commissariat A L'Energie Atomique et AUX
• Inventors: Davoust, Laurent, Fouillet, Yves
• Granted Patent: US 8,444,836 B2
• Time in Patent Office: Days
• US Class Current: 204/454
• CPC Class Codes: B01F 23/41 Emulsifying
• CPC Class Codes: B01F 33/3021 the components to be mixed being combined in a single independent droplet, e.g. these droplets being divided by a non-miscible fluid or consisting of independent droplets
• CPC Class Codes: B01F 33/3031 using electro-hydrodynamic [EHD] or electro-kinetic [EKI] phenomena to mix or move the fluids
• CPC Class Codes: B01L 2200/0647 Handling flowable solids, e.g. microscopic beads, cells, particles
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: B01L 3/5085 for multiple samples, e.g. microtitration plates
• CPC Class Codes: B01L 3/5088 confining liquids at a location by surface tension, e.g. virtual wells on plates, wires B01L3/50857 takes precedence
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence

Abstract

A device for forming at least one circulating flow, or vortex, at the surface of a drop of liquid, including at least two first electrodes forming a plane and having edges facing each other, such that the contact line of a drop, deposited on the device and fixed relatively to the device, has a tangent forming, when projected onto the plane of the electrodes, an angle between 0° and 90° with the edges facing each other of the electrodes.

Claims

1-30. -30. (canceled)

31. A device for forming at least one circulating flow, or vortex, at the surface of a drop of liquid, comprising:

at least two first electrodes forming a plane and having edges facing each other, such that the contact line of a drop, deposited on the device and fixed relatively to the device, has a tangent forming, when projected onto the plane of the electrodes, an angle between 0° and

90°

with the edges facing each other of the electrodes; and

a potential generating device allowing application between the two first electrodes of a potential difference which gives rise to an oblique electric field.

32. The device according to claim 31, wherein the angle is between 40°

and 50°

.

33. The device according to claim 31, the edges of the electrodes facing each other having a zigzag shape.

34. The device according to claim 31, the edges of the electrodes facing each other having the shape of a logarithmic spiral.

35. The device according to claim 31, the electrodes being 2, 4, or 8 in number.

36. The device according to claim 31, the edges of the electrodes forming with the projection of the contact line, an angle between 0°

and 90°

, alternating with electrode edges forming an angle of 90°

with the projection of this same circular contact line.

37. The device according to claim 31, further comprising means for successively activating and deactivating the electrodes at a frequency above 100 Hz.

38. The device according to claim 31, separation spaces of the edges of the electrodes facing each other having alternately a first value and a second value that is less than the first value.

39. The device according to claim 31, further comprising means for trapping a triple line which a drop laid on the device defines with the device.

40. The device according to claim 31, further comprising a second set of electrodes located opposite, parallel to the two first electrodes.

41. The device according to claim 40, the second set of electrodes forming a second device for forming at least one circulating flow, or vortex, at the surface of a drop of liquid.

42. The device according to claim 31, further comprising a tip-shaped counter-electrode.

43. A pumping device comprising:

at least one device according to claim 31; and

means for bringing a second fluid into contact with a drop of liquid positioned on the device.

44. The device according to claim 43, further comprising a plurality of the at least one device.

45. The device according to claim 31, further comprising an insulating layer.

46. A method for forming at least one circulating flow or vortex in a drop of liquid, or at its surface, in a surrounding medium, having relatively to each other different dielectric properties and/or different resistivities, comprising:

positioning the drop on a device including at least two first electrodes having edges facing each other, so that the projection of the contact line of the drop on the plane containing the electrodes has a tangent forming with these electrode edges an angle between 0° and

90°

; and

applying an electric field between the two electrodes, the drop being fixed relatively to the device.

47. The method according to claim 46, the electric field applied between the two first electrodes being an oblique electric field relatively to the liquid/surrounding medium interface.

48. The method according to claim 46, the volume of the drop varying as a function of time.

49. The method according to claim 46, wherein a single circulating flow or a single vortex is generated in the drop.

50. A microfluidic concentration method by mixing or centrifuging a drop of liquid, for detecting antibodies, or antigens, or proteins or protein complexes, or DNAs or RNAs, comprising:

application of a method for forming at least one circulating flow or vortex in said drop of liquid, in accordance with a method according to claim 46.

51. The method according to claim 50, a detection being carried out, after mixing or centrifuging, without displacement of the drop.

52. The method according to claim 51, further comprising extracting liquid from the drop.

53. The method according to claim 52, further comprising transferring extracted liquid towards a detection area.

54. The method according to claim 52, the extracting being carried out by electrowetting or by emitting droplets from a Taylor cone.

55. A method for forming a microemulsion comprising:

bringing two volumes of liquids closer by displacing them relative to each other, and applying a method according to claim 46.

56. The method according to claim 55, the bringing closer two volumes of liquids displaces them being carried out by electrowetting.

57. A method for pumping a secondary fluid by a drop of primary fluid, comprising:

application of a method for forming at least one circulating flow or vortex in said drop of primary fluid, in accordance with a method according to claim 46.

58. A method for extracting an analyte from a drop of liquid comprising:

application of microfluidic concentration method according to claim 50;

deactivation of the at least two first electrodes, and formation of a capillary bridge between the first insulating surface and a wall including at least a second electrode; and

electric activation of the first electrodes and of the second electrode, and cutting of the capillary bridge.

59. A method for extracting particles comprising:

application of a method according to claim 46, a surrounding medium including a second liquid containing particles which have settled beforehand on the interface of the two liquids; and

separation of the side portions, containing the particles, and of a central portion of the drop.

60. The method according to claim 59, the separation of the side portions, containing the particles, and of a central portion of the drop, taking place by cutting by electrowetting.