Droplet Actuator Configurations and Methods

• US 20100307917A1
• Filed: 12/10/2008
• Published: 12/09/2010
• Est. Priority Date: 12/10/2007
• Status: Active Grant

• Current Assignee: Advanced Liquid Logic, Inc. (Illumina Incorporated)
• Original Assignee: Advanced Liquid Logic, Inc. (Illumina Incorporated)
• Inventors: Sudarsan, Arjun, Eckhardt, Allen, Srinivasan, Vijay, Pollack, Michael G., Hua, Zhishan
• Granted Patent: US 8,562,807 B2
• Time in Patent Office: Days
• US Class Current: 204/450
• CPC Class Codes: B01L 2200/0605 Metering of fluids
• CPC Class Codes: B01L 2200/061 Counting droplets
• CPC Class Codes: B01L 2200/0647 Handling flowable solids, e.g. microscopic beads, cells, particles
• CPC Class Codes: B01L 2300/0645 Electrodes
• CPC Class Codes: B01L 2300/16 Surface properties and coatings
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 2400/0427 Electrowetting
• CPC Class Codes: B01L 3/0268 using pulse dispensing or spraying, eg. inkjet type, piezo actuated ejection of droplets from capillaries
• CPC Class Codes: B01L 3/502761 specially adapted for handling suspended solids or molecules independently from the bulk fluid flow, e.g. for trapping or sorting beads, for physically stretching molecules investigating characteristics of particles G01N15/00
• CPC Class Codes: B01L 3/502792 for moving individual droplets on a plate, e.g. by locally altering surface tension
• CPC Class Codes: G01N 27/44743 Introducing samples

Abstract

Droplet actuators for conducting droplet operations, such as droplet transport and droplet dispensing, are provided. In one embodiment, the droplet actuator may include a substrate including, droplet operations electrodes arranged for conducting droplet operations on a surface of the substrate; and reference electrodes associated with the droplet operations electrodes and extending above the surface of the substrate. Other embodiments of droplet actuators and methods of loading and using such droplet actuators are also provided.

Claims

1. A droplet actuator comprising a substrate comprising:

(a) droplet operations electrodes arranged for conducting droplet operations on a surface of the substrate; and

(b) reference electrodes associated with the droplet operations electrodes and extending above the surface of the substrate.

2. A droplet actuator comprising:

(a) two substrates separated to form a gap;

(b) droplet operations electrodes associated with at least one of the substrates and arranged for conducting droplet operations in the gap; and

(c) reference electrodes associated with at least one of the substrates and extending into the gap.

3. A droplet actuator comprising a substrate comprising droplet operations electrodes and reference electrodes configured for conducting droplet operations, wherein at least a subset of the reference electrodes is separated from a droplet operations surface by an insulator and/or dielectric material.

4. A droplet actuator comprising:

(a) two substrates separated to form a gap;

(b) droplet operations electrodes associated with at least one of the substrates and arranged for conducting droplet operations in the gap; and

(c) reference electrodes;

(i) associated with at least one of the substrates; and

(ii) separated from a droplet operations surface of the substrate of (c)(i) by an insulator and/or a dielectric material.

5. A droplet actuator comprising a substrate comprising:

(a) droplet operations electrodes configured for conducting one or more droplet operations; and

(b) reference electrodes inset into and/or between and/or interdigitated with one or more droplet operations electrodes.

6. The droplet actuator of claim 5 comprising a reference electrode inset into a droplet operations electrode.

7. The droplet actuator of claim 5 comprising a reference electrode inset between two or more droplet operations electrodes.

8. The droplet actuator of claim 5 comprising a reference electrode interdigitated with a droplet operations electrode.

9-11. -11. (canceled)

12. A droplet actuator comprising an electrode that is rotationally but not reflectively symmetrical.

13. The droplet actuator of claim 12 comprising a path and/or array of the electrodes.

14. The droplet actuator of claim 13 wherein the electrodes are interdigitated.

15. The droplet actuator of claim 13 wherein the electrodes are not interdigitated.

25. The droplet actuator of claim 12 wherein the rotational symmetry is X-fold, and for each electrode X is 3, 4, 5, 6, 7, 8, 9, and/or 10.

26. The droplet actuator of claim 12 wherein the droplet actuator comprises a path and/or array of the electrodes, wherein adjacent electrodes are arranged such that no line can be drawn between two adjacent electrodes without overlapping one or both of the two adjacent electrodes.

27. The droplet actuator of claim 26 wherein the electrodes are not interdigitated.

28. The droplet actuator of claim 26 wherein the electrodes are interdigitated.

16-24. -24. (canceled)

29-38. -38. (canceled)

39. A droplet actuator comprising:

(a) a first substrate comprising droplet operations electrodes configured for conducting one or more droplet operations; and

(b) a second substrate comprising;

(i) a conductive layer at least partially contiguous with two or more of the droplet operations electrodes; and

(ii) a perfluorophosphonate coating overlying at least a portion of the conductive layer;

wherein the first substrate and the second substrate are separated to form a gap for conducting droplet operations mediated by the droplet operations electrodes.

40. The droplet actuator of claim 39 wherein the conductive layer comprises indium tin oxide.

41. A droplet actuator comprising:

(a) two surfaces separated to form a gap;

(b) electrodes associated with one or more surfaces and arranged for conducting one or more droplet operations;

(c) a filler fluid in the gap;

(d) a reservoir comprising a droplet fluid in the reservoir;

(e) a fluid path from the reservoir into the gap;

(f) optionally, an filler fluid opening arranged for permitting fluid to exit the gap and/or exit one portion of the gap into another portion of the gap; and

(g) a pressure source configured to force dislocation of filler fluid in the gap and/or through the filler fluid opening and thereby force droplet fluid from the reservoir through the fluid path into the gap.

42. The droplet actuator of claim 41 wherein the pressure source is configured such that the dislocation of filler fluid forces droplet fluid from the reservoir through the fluid path into the gap into sufficient proximity with one or more of the electrodes to enable one or more droplet operations to be mediated by the one or more of the electrodes.

43. The droplet actuator of claim 41 wherein the pressure source comprises a negative pressure source.

44. The droplet actuator of claim 41 wherein the pressure source comprises a positive pressure source.

45. The droplet actuator of claim 41 comprising multiple reservoirs each arranged to permit a droplet fluid to be loaded into the gap.

46. The droplet actuator of claim 42 wherein the droplet operation comprises a droplet dispensing operation in which a droplet is dispensed from the droplet fluid.

47. A method of loading a droplet actuator, the method comprising:

(a) providing;

(i) a droplet actuator loaded with a filler fluid;

(ii) a reservoir comprising a droplet fluid; and

(iii) a fluid path extending from the reservoir into the droplet actuator; and

(b) forcing filler fluid;

(i) from one locus in the droplet actuator to another locus in the droplet actuator;

or

(ii) out of the droplet actuator;

thereby causing droplet fluid to flow through the fluid path and into the droplet actuator.

48. The method of claim 47 wherein step (b) comprises forcing droplet fluid into sufficient proximity with one or more electrodes to enable one or more droplet operations to be mediated in the droplet actuator by the one or more electrodes.

49. The method of claim 47 wherein step (b) comprises forcing the filler fluid using a negative pressure source.

50. The method of claim 47 wherein step (b) comprises forcing the filler fluid using a positive pressure source.

51. The method of claim 47 wherein multiple droplet fluids are loaded from multiple reservoirs.

52. The method of claim 48 wherein the droplet operation comprises a droplet dispensing operation in which a droplet is dispensed from the droplet fluid.

53. A method of conducting a droplet operation on a droplet actuator, the method comprising:

(a) using a negative pressure to flow a source fluid into a droplet actuator gap into proximity with a droplet operations electrode; and

(b) using the droplet operations electrode along with other droplet operations electrodes to conduct the droplet operation.

54. The method of claim 53 wherein the droplet operation comprises dispensing a droplet from the source fluid.