Methods of dispensing and withdrawing liquid in an electrowetting device

1. A method of dispensing liquid, the method comprising:

(a) providing an electrowetting device comprising a first substrate and a second substrate spaced apart to form a gap, and an electrowetting array comprising a plurality of electrowetting electrodes on opposite sides of the gap;

(b) transporting a droplet between at least two reaction zones maintained at different temperatures in the gap to produce a thermal cycled droplet, wherein the droplet moves along the gap by electrowetting caused by the droplet contacting the electrodes on the opposite sides of the gap;

(c) positioning the thermal cycled droplet at a specific locus in the gap using the electrowetting array to produce a repositioned droplet; and

(d) dispensing the repositioned droplet at the specific locus through a hole in a housing or substrate of the electrowetting device.

2. The method of claim 1 wherein the dispensing comprises using pressure for dispensing the droplet through the hole.

3. The method of claim 1 wherein the dispensing comprises using suction for dispensing the droplet through the hole.

4. The method of claim 1 wherein the dispensing comprises using a capillary for dispensing the droplet through the hole.

5. The method of claim 1 wherein the dispensing comprises using a pipette for dispensing the droplet through the hole.

6. The method of claim 1 wherein the droplet comprises a reaction droplet.

7. The method of claim 1 wherein the droplet comprises DNA.

8. The method of claim 1 wherein the droplet comprises PCR reagents.

9. The method of claim 1 , wherein the gap comprises a filler fluid and the droplet is immiscible with the filler fluid comprising an oil.

10. The method of claim 9 , wherein the oil comprises a silicone oil.

11. A method of withdrawing liquid, the method comprising:

(a) providing an electrowetting device comprising a first substrate and a second substrate spaced apart to form a gap, and an electrowetting array comprising a plurality of electrowetting electrodes on opposite sides of the gap;

(b) transporting a droplet between at least two reaction zones maintained at different temperatures in the gap to produce a thermal cycled droplet, wherein the droplet moves along the gap by electrowetting caused by the droplet contacting the electrodes on the opposite sides of the gap;

(c) positioning the thermal cycled droplet at a specific locus in the gap using the electrowetting array to produce a repositioned droplet; and

(d) withdrawing the repositioned droplet from the specific locus through a hole in a housing or substrate of the electrowetting device.

12. The method of claim 11 wherein the withdrawing comprises using pressure for withdrawing the droplet through the hole.

13. The method of claim 11 wherein the withdrawing comprises using suction for withdrawing the droplet through the hole.

14. The method of claim 11 wherein the withdrawing comprises using a capillary for withdrawing the droplet through the hole.

15. The method of claim 11 wherein the withdrawing comprises using a pipette for withdrawing the droplet through the hole.

16. The method of claim 11 wherein the droplet comprises a reaction droplet.

17. The method of claim 11 wherein the droplet comprises DNA.

18. The method of claim 11 wherein the droplet comprises PCR reagents.

19. The method of claim 11 , wherein the gap comprises a filler fluid and the droplet is immiscible with the filler fluid comprising an oil.

20. The method of claim 19 , wherein the oil comprises a silicone oil.