Inertia Enhanced Pumping Mechanism And Method

• US 20120152361A1
• Filed: 12/20/2010
• Published: 06/21/2012
• Est. Priority Date: 12/20/2010
• Status: Abandoned Application

• Current Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Inventors: Williams, Justin C., Beebe, David J., Resto, Pedro, Berthler, Erwin
• Application Number:
  US12/973,188
• Publication Number:
  US 20120152361A1
• Time in Patent Office: Days
• US Class Current: 137/1
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0475 specific mechanical means and fluid pressure
• 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 3/50273 characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043
• CPC Class Codes: Y10T 137/0318 Processes
• CPC Class Codes: Y10T 137/2076 Utilizing diverse fluids

Abstract

A device and method are provided for pumping fluid through a channel of a microfluidic device. The channel has an input and an output. The channel is filled with fluid and droplets under pressure are sequentially directed at the input of the channel so as to cause fluid to flow in the channel towards the output.

Claims

1. A device for the surface tension pumping of fluid though a channel of a microfluidic device, the channel including an input and an output, comprising:

a first fluid received in the channel, the first fluid having an input air-fluid interface at the input of the channel and an output air-fluid interface at the output of the channel; and

a fluid jet at a user selected angle to the input air-fluid interface, the fluid jet selectively directing a second fluid under pressure at the input air-fluid interface of the first fluid so as to cause fluid flow in the channel towards the output.

2. The device of claim 1 wherein the fluid jet is a first fluid jet and wherein the device further comprises a second fluid jet at a user selected angle to the output air-fluid interface, the second fluid jet selectively directing a third fluid under pressure at the output air-fluid interface of the first fluid so as to cause fluid flow in the channel towards the input.

3. The device of claim 2 wherein the input and output of the channel lie in corresponding planes and wherein the first fluid jet is at an angle of less than 90 degrees to the plane of the input and the second fluid jet is at an angle of less than 90 degrees to the plane of the output.

4. The device of claim 1 wherein the input of the channel lies in a plane and wherein the fluid jet is at an angle of less than 90 degrees to the plane.

5. The device of claim 1 wherein the second fluid is at least partially defined by a first droplet and wherein the fluid jet directs a series of droplets under pressure at the input air-fluid interface of the first fluid.

6. The device of claim 1 wherein the fluid jet is a first fluid jet and wherein the device further comprises a second fluid jet at a user selected angle to the input air-fluid interface, the second fluid jet directing a third fluid under pressure at the input air-fluid interface of the fluid.

7. The device of claim 6 wherein the second fluid directed by the first fluid jet is spaced in time from the third fluid directed by the second fluid jet.

8. The device of claim 1 wherein the fluid jet includes a nozzle, the nozzle being spaced from the input air-fluid interface.

9. A method of pumping fluid, comprising the steps of:

providing a microfluidic device having a channel therethough, the channel having an input and an output;

filing the channel with a first fluid; and

selectively directing a second fluid under pressure at the input of the channel so as to cause fluid flow in the channel towards the output.

10. The method of claim 9 comprising the additional step of selectively directing a third fluid under pressure at the output of the channel so as to cause fluid flow in the channel towards the input.

11. The method of claim 10 wherein the input and output of the channel lie in corresponding planes and wherein the second fluid directed at the input travels along an axis at an angle of less than 90 degrees to the plane of the input and the third fluid directed at the output travels along an axis at an angle of less than 90 degrees to the plane of the output.

12. The method of claim 9 wherein the input of the channel lies in a plane and wherein the second fluid directed at the input travels along an axis at an angle of less than 90 degrees to the plane of the input.

13. The method of claim 9 wherein the second fluid is at least partially defined by a first droplet and wherein the method includes the additional step of directing a series of droplets under pressure at the input of the channel.

14. The method of claim 9 wherein the second fluid is at least partially defined by a first droplet and the first droplet is directed by a first fluid jet and wherein the method comprises the additional step of selectively directing a second droplet under pressure at the input of the channel by a second fluid jet.

15. The method of claim 14 wherein the first droplet directed by the first fluid jet is spaced in time from the second droplet directed by the second fluid jet.

16. A method of pumping fluid through a channel of a microfluidic device, the channel having an input and an output, comprising the steps of:

filling the channel with a first fluid such that the first fluid at the input has a surface tension pressure; and

selectively directing a volume of a second fluid under pressure at the input of the channel so as to cause fluid in the channel to flow towards the output.

17. The method of claim 16 wherein the step of selectively directing a volume of the second fluid under pressure at the input of the channel includes the steps of sequentially directing a plurality of droplets under pressure at the input of the channel.

18. The method of claim 17 comprising the additional step of selectively directing a plurality of droplets under pressure at the output of the channel so as to cause fluid in the channel to flow towards the input.

19. The method of claim 18 wherein the input and output of the channel lie in corresponding planes and wherein each droplet directed at the input travels along an axis at an angle of less than 90 degrees to the plane of the input and each droplet directed at the output travels along an axis at an angle of less than 90 degrees to the plane of the output.

20. The method of claim 17 wherein the input of the channel lies in a plane and wherein each droplet directed at the input travels along an axis at an angle of less than 90 degrees to the plane of the input.

21. The method of claim 17 wherein each droplet directed under pressure at the input of the channel is directed by a first fluid jet.

22. The method of claim 21 further comprising the additional step of selectively directing a second plurality of droplets under pressure at the input of the channel by a second fluid jet.

23. The method of claim 22 wherein each droplet directed by the first fluid jet is spaced in time from each droplet directed by the second fluid jet.

24. The method of claim 16 wherein the channel is defined by a wall and wherein the step of filling the channel includes the additional step of directing a volume of the first fluid under pressure at the wall of the channel such that the channel is filled with the fluid.

25. The method of claim 24 wherein:

the volume of first fluid is directed at the wall of the channel has a dynamic pressure;

an adhesion force is provided between the first fluid in the channel and the wall of the channel; and

the adhesion force is greater than the dynamic pressure.

26. The method of claim 16 wherein:

the channel has a boundary;

an adhesion force is provided between the first fluid in the channel and the boundary of the channel;

the volume of the second fluid has a dynamic pressure;

the volume of the second fluid directed at the input of channel travels along an axis free of contact with the boundary; and

the dynamic pressure of the volume of the second fluid overcomes the adhesion force.

27. A method of pumping fluid, comprising the steps of:

providing a microfluidic device having a channel therethough, the channel having an input and an output;

filing the channel with a first fluid;

creating a low pressure region in the first fluid at the input of the channel; and

selectively providing a second fluid at the low pressure region in the first fluid at the input of the channel such that the second fluid flows in the channel towards the output.

28. The method of claim 27 wherein the second fluid is a suspension.

29. The method of claim 27 wherein the step of creating a low pressure region includes the step of directing a droplet under pressure at the input of the channel.