Techniques and droplet actuator designs for reducing bubble formation

Patent metadata

Field	Value
Publication number	US-9815061-B2
Application number	US-201414549113-A
Country	US
Kind code	B2
Filing date	Nov 20, 2014
Priority date	Jun 27, 2012
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

During droplet operations in a droplet actuator, bubbles often form in the filler fluid in the droplet operations gap and interrupt droplet operations. The present invention provides methods and systems for performing droplet operations on a droplet in a droplet actuator comprising maintaining substantially consistent contact between the droplet and an electrical ground while conducting multiple droplet operations on the droplet in the droplet operations gap and/or reducing the accumulation of electrical charges in the droplet operations gap during multiple droplet operations. The methods and systems reduce or eliminate bubble formation in the filler fluid of the droplet operations gap, thereby permitting completion of multiple droplet operations without interruption by bubble formation in the filler fluid in the droplet operations gap.

First claim

What is claimed:

1. A method of performing droplet operations on a droplet in a droplet actuator, comprising:
providing the droplet actuator, comprising:
a top substrate and a bottom substrate separated to form a droplet operations gap;
a conductive layer in contact with a surface of the top substrate, wherein the conductive layer provides a ground plane;
a dielectric layer in contact with the conductive layer, wherein an area of the dielectric layer has a sawtooth texture that extends into the droplet operations gap;
an arrangement of droplet operations electrodes in contact with the bottom substrate and arranged for conducting droplet operations thereon;
filling the droplet operations gap of the droplet actuator with a filler fluid;
providing a droplet in the droplet operations gap;
conducting multiple droplet operations on the droplet in the droplet operations gap,
wherein the droplet is transported through the filler fluid in the droplet operations gap; and
maintaining substantially consistent contact between the droplet and the sawtooth structure, and thus an electrical ground at the ground plane, while conducting the multiple droplet operations on the droplet in the droplet operations gap;

wherein the substantially consistent contact between the droplet and the electrical ground permits completion of the multiple droplet operations without interruption by bubble formation in the filler fluid in the droplet operations gap.

2. The method according to claim 1 , further comprising heating the droplet in the droplet operations gap.

3. The method according to claim 1 , further comprising heating the droplet in the droplet operations gap to at least sixty percent of a boiling point of the droplet.

4. The method according to claim 1 , wherein conducting the multiple droplet operations comprises conducting at least 10 droplet operations without the interruption by the bubble formation in the filler fluid in the droplet operations gap.

5. The method according to claim 1 , further comprising heating the droplet in the droplet operations gap to at least sixty percent of a boiling point of the droplet, wherein conducting the multiple droplet operations comprises conducting at least 10 droplet operations without the interruption by the bubble formation in the filler fluid in the droplet operations gap.

6. The method according to claim 5 , wherein conducting the multiple droplet operations comprises conducting at least 100 droplet operations without the interruption by the bubble formation in the filler fluid in the droplet operations gap.

7. The method according to claim 5 , wherein conducting the multiple droplet operations comprises conducting at least 1,000 droplet operations without the interruption by the bubble formation in the filler fluid in the droplet operations gap.

8. The method according to claim 5 , wherein conducting the multiple droplet operations comprises conducting at least 100,000 droplet operations without the interruption by the bubble formation in the filler fluid in the droplet operations gap.

9. The method according to claim 1 , further comprising heating the droplet in the droplet operations gap to at least sixty percent of a boiling point of the droplet, wherein conducting the multiple droplet operations comprises completing an assay without the interruption by the bubble formation in the filler fluid in the droplet operations gap.

10. The method according to claim 1 , further comprising heating the droplet in the droplet operations gap to at least sixty percent of a boiling point of the droplet, wherein conducting the multiple droplet operations comprises completing multiple cycles of a polymerase chain reaction without the interruption by the bubble formation in the filler fluid in the droplet operations gap.

11. The method according to claim 1 , further comprising heating the droplet in the droplet operations gap to a minimum temperature of seventy five degrees Celsius, wherein conducting the multiple droplet operations comprises completing an assay without the interruption by the bubble formation in the filler fluid in the droplet operations gap.

12. The method according to claim 1 , further comprising heating the droplet in the droplet operations gap to within twenty degrees Celsius of a boiling point of the droplet, wherein conducting the multiple droplet operations comprises completing an assay without the interruption by the bubble formation in the filler fluid in the droplet operations gap.

13. The method according to claim 1 , wherein the droplet comprises multiple droplets in the droplet operations gap, and wherein substantially consistent contact is maintained between multiple droplets and the electrical ground while conducting multiple droplet operations on the multiple droplets in the droplet operations gap.

14. The method according to claim 1 , wherein the filler fluid is an electrically conductive filler fluid.

15. The method according to claim 1 , further comprising merging the droplet with another droplet to maintain the substantially consistent contact with the electrical ground while conducting the multiple droplet operations on the droplet in the droplet operations gap.

16. A method of performing droplet operations on a droplet in a droplet actuator, comprising:
providing the droplet actuator comprising a top substrate and a bottom substrate separated to form a droplet operations gap, wherein the droplet actuator further comprises an arrangement of droplet operations electrodes arranged for conducting droplet operations thereon;
filling the droplet operations gap of the droplet actuator with a filler fluid;
providing the droplet in the droplet operations gap;
conducting multiple droplet operations on the droplet in the droplet operations gap, wherein the droplet is transported through the filler fluid in the droplet operations gap; and
adjusting a height of the droplet operations gap to maintain substantially consistent contact between the droplet and an electrical ground while conducting the multiple droplet operations on the droplet in the droplet operations gap;
wherein the substantially consistent contact between the droplet and the electrical ground permits completion of the multiple droplet operations without interruption by bubble formation in the filler fluid in the droplet operations gap.

17. The method according to claim 16 , further comprising grounding the top substrate of the droplet actuator to the electrical ground and maintaining substantially consistent contact between the droplet and the top substrate while conducting the multiple droplet operations on the droplet in the droplet operations gap.

18. The method according to claim 16 , further comprising reducing the height of the droplet operations gap to maintain the substantially consistent contact between the droplet and the electrical ground while conducting the multiple droplet operations on the droplet in the droplet operations gap.

19. The method according to claim 16 , further comprising adjusting the height of the droplet operations gap with a spring to maintain the substantially consistent contact between the droplet and electrical ground while conducting the multiple droplet operations on the droplet in the droplet operations gap.

20. A method of performing droplet operations on a droplet in a droplet actuator, comprising:
providing the droplet actuator comprising a top substrate and a bottom substrate separated to form a droplet operations gap, wherein the droplet actuator further compr

Assignees

• Advanced Liquid Logic Inc
• Illumina France Sarl

Inventors

• Delattre Cyril
• Rival Arnaud
• Srinivasan Vijay

Classifications

• B01L2400/0448

  Marangoni flow; Thermocapillary effect · CPC title

• B01L2400/0406

  capillary forces · CPC title

• B01L2300/089

  Virtual walls for guiding liquids · CPC title

• B01L2400/043

  magnetic forces · CPC title

• B01L3/502784 Primary

  specially adapted for droplet or plug flow, e.g. digital microfluidics · CPC title