Bubble Techniques for a Droplet Actuator

• US 20100190263A1
• Filed: 01/25/2010
• Published: 07/29/2010
• Est. Priority Date: 01/23/2009
• Status: Active Grant

• Current Assignee: Advanced Liquid Logic, Inc. (Illumina Incorporated)
• Original Assignee: Advanced Liquid Logic, Inc. (Illumina Incorporated)
• Inventors: Sudarsan, Arjun, Srinivasan, Vijay, Pollack, Michael G., Hua, Zhishan
• Granted Patent: US 8,877,512 B2
• Time in Patent Office: Days
• US Class Current: 436/174
• CPC Class Codes: B01F 33/3031 using electro-hydrodynamic [EHD] or electro-kinetic [EKI] phenomena to mix or move the fluids
• CPC Class Codes: B01F 33/30351 using hydrophilic/hydrophobic surfaces
• CPC Class Codes: B01F 33/30352 using roughness of the surfaces
• CPC Class Codes: B01L 2200/0673 Handling of plugs of fluid surrounded by immiscible fluid
• CPC Class Codes: B01L 2300/0867 Multiple inlets and one sample wells, e.g. mixing, dilution
• CPC Class Codes: B01L 2300/089 Virtual walls for guiding liquids
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0427 Electrowetting
• CPC Class Codes: B01L 2400/0688 surface tension valves, capillary stop, capillary break
• CPC Class Codes: B01L 3/502723 characterised by venting arrangements
• CPC Class Codes: B01L 3/502738 characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: B01L 3/502792 for moving individual droplets on a plate, e.g. by locally altering surface tension
• CPC Class Codes: C07K 1/26 Electrophoresis
• CPC Class Codes: G01N 2001/2244 Exhaled gas, e.g. alcohol detecting
• CPC Class Codes: G01N 2035/1034 Transferring microquantities of liquid
• CPC Class Codes: Y10T 436/25 including sample preparation

Abstract

The present invention is directed to a droplet actuator and methods of making and using the droplet actuator including one or more substrates configured to form a droplet operations gap and including a physical or chemical feature that may be provided at a predetermined locus within or exposed to the droplet operations gap and configured to retain a bubble in position within the droplet operations gap.

Claims

1. A droplet actuator comprising:

(a) one or more substrates configured to form a droplet operations gap; and

(b) a physical or chemical feature provided at a predetermined locus within or exposed to the droplet operations gap and configured to retain a bubble in position within the droplet operations gap.

2. The droplet actuator of claim 1 further comprising a bubble formed in the droplet operations gap at the chemical or physical feature and surrounded by a liquid filler fluid.

3. The droplet actuator of claim 1 further comprising more than one of the physical or chemical features.

4. The droplet actuator of claim 3 further comprising an array of the chemical or physical features and an array of bubbles formed in the droplet operations gap and surrounded by a liquid filler fluid.

5. The droplet actuator of claim 2 wherein the physical feature comprises a recessed region of a surface of the one or more substrates facing the droplet operations gap.

6. The droplet actuator of claim 2 wherein the physical feature comprise recessed regions of opposing surfaces of the one or more substrates facing the droplet operations gap.

7. The droplet actuator of claim 2 wherein the physical feature comprises a chemically treated region of a surface of the one or more substrates facing the droplet operations gap.

8. The droplet actuator of claim 2 wherein the physical feature comprises a hydrophilic or lipophobic region of a surface of the one or more substrates facing the droplet operations gap.

9. The droplet actuator of claim 2 wherein the bubble spans the gap between opposing surfaces of the one or more substrates facing the droplet operations gap.

10. The droplet actuator of claim 2 wherein the bubble comprises a gaseous bubble substantially surrounded by oil within the droplet operations gap.

11. The droplet actuator of claim 2 wherein the bubble comprises a gaseous bubble at least partially surrounded by oil within the droplet operations gap.

12. The droplet actuator of claim 2 wherein the filler fluid comprises oil.

13. The droplet actuator of claim 2 wherein the filler fluid comprises low viscosity oil.

14. The droplet actuator of claim 2 wherein the filler fluid comprises low viscosity oil doped with a surfactant.

15. The droplet actuator of claim 1 wherein:

(a) the one or more substrates comprise a top substrate and a bottom substrate; and

(b) the bottom substrate is separated from the top substrate by a gap defined by a spacer to form the droplet operations gap.

16. The droplet actuator of claim 15 wherein the physical feature comprises a recessed region of a surface of the one or more substrates facing the droplet operations gap

17. The droplet actuator of claim 16 wherein the recessed region is on the top substrate facing the bottom substrate, and the bottom substrate further comprises a recessed region opposite to the recessed region of the top substrate.

18. The droplet actuator of claim 16 wherein the recessed region is formed by a technique comprising patterning, embossing and/or etching.

19. The droplet actuator of claim 17 wherein the top substrate recessed region and bottom substrate recessed region are of sufficient depth to form a bubble as filler fluid is flowed into the gap, and for retaining a bubble in position in the gap.

20. The droplet actuator of claim 16 wherein the recessed region is provided only in the top substrate.

21. The droplet actuator of claim 16 wherein the recessed region is provided only in the bottom substrate.

22. The droplet actuator of claim 2 further comprising a fluid reservoir formed in the droplet operations gap and comprising the bubble, the fluid reservoir comprising fluid barriers which at least partially surround the bubble.

23. The droplet actuator of claim 22 further comprising a path of electrodes arranged for transporting a droplet situated in the droplet operations gap into the reservoir.

24. The droplet actuator of claim 2 wherein the bubble is arranged to restrain movement of a droplet in the filler fluid.

25. The droplet actuator of claim 2 wherein the droplet actuator comprises a fluid path arranged for flowing fluid from a source which is external to the droplet operations gap into the bubble.

26. The droplet actuator of claim 2 comprising a dried reagent situated within the gasseous bubble.

27. The droplet actuator of claim 4 comprising an array of dried reagent, each dried reagent situated within a gaseous bubble in the array of bubbles.

28. The droplet actuator of claim 2 wherein the bubble comprises a preselected gas composition.

29. The droplet actuator of claim 2 wherein the bubble comprises a preselected gas composition that is not air.

30. The droplet actuator of claim 2 wherein the bubble consists substantially of a single gas.

31. The droplet actuator of claim 2 wherein the bubble is formed under pressure.

32. The droplet actuator of claim 2 further comprising a temperature control element arranged to control temperature of the bubble.

33. The droplet actuator of claim 2 further comprising one or more physical barriers arranged to restrain movement of the bubble.

34. A method of forming a bubble in a droplet actuator, the method comprising:

(a) providing the droplet actuator of claim 1; and

(b) dispensing filler fluid into the droplet operations gap at a rate and volume sufficient to fill the fluid reservoir and form an gaseous bubble at the physical and/or chemical feature.

35. A method of providing a droplet actuator comprising a bubble in a droplet operations gap thereof, the method comprising:

(a) forming a gaseous bubble in a droplet operations gap of a droplet actuator, wherein the bubble is at least partially surrounded by a filler fluid and, optionally, partially surrounded by one or more droplet actuator surfaces; and

(b) forming a droplet in the filler fluid, wherein the droplet is substantially immiscible with and surrounded by the filler fluid.

36. The method of claim 35 wherein the bubble is compressed within the droplet operations gap.

37. The method of claim 35 wherein the bubble is compressed within the droplet operations gap and is substantially discoid in shape.

38. The method of claim 35 further comprising transporting the droplet from the filler fluid into the bubble.

39. The method of claim 35 wherein the droplet is compressed within the droplet operations gap such that the droplet is substantially discoid in shape.

40. The method of claim 35 further comprising providing a dried reagent in the bubble.

41. The method of claim 40 further comprising transporting the droplet actuator including the dried reagent in the bubble.

42. The method of claim 41 further comprising reconstituting the dried reagent in the bubble.

43. The method of claim 41 further comprising transporting a droplet from the filler fluid into the bubble to reconstitute the dried reagent.

44. The method of claim 43 wherein transporting the droplet from the filler fluid into the bubble is mediated by electrodes associated with a substrate of the droplet actuator.

45. The method of claim 35 wherein forming a gaseous bubble in a droplet operations gap of a droplet actuator comprises flowing a filler fluid into a droplet operations gap comprising features selected to cause formation of a bubble in the droplet operations gap at a predetermined locus.

46. The method of claim 36 further comprising subjecting the droplet to one or more droplet operations within the bubble.

47. The method of claim 35 wherein the bubble comprises a preselected gas composition.

48. The method of claim 35 wherein the bubble consists substantially of a single gas.

49. The method of claim 35 wherein the bubble is formed under pressure.

50. The method of claim 36 further comprising evaporating the droplet within the bubble.

51. The method of claim 36 further comprising evaporating a portion of the droplet to concentrate one or more components in the droplet.

52. The method of claim 35 wherein the droplet actuator comprises one or more physical barriers in the reservoir for supporting and retaining the bubble in the reservoir.

53. The method of claim 35 further comprising flowing the bubble out of the droplet operations gap.

54. The method of claim 35 further comprising flowing the bubble into a different region of the droplet operations gap.

55. The method of claim 35 further comprising using the bubble to prevent movement of the droplet.