Self-regulating microfluidic device and method of using the same

• US 6,523,559 B2
• Filed: 07/27/2001
• Issued: 02/25/2003
• Est. Priority Date: 07/27/2001
• Status: Expired due to Term

• Current Assignee: Board of Trustees of The University of Illinois, Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Inventors: Moore, Jeffrey S., Eddington, David T., Liu, Robin, Beebe, David J.
• Primary Examiner(s): Hepperle, Stephen M.
• Application Number:
  US09/917,523
• Publication Number:
  US 20030019520A1
• Time in Patent Office: 578 Days
• Field of Search: 137/3, 137/88, 137/93, 137/89, 137/91, 137/92, 236/12.14
• US Class Current: 137/3
• CPC Class Codes: G05D 11/08 by sensing concentration of mixture, e.g. measuring pH value
• CPC Class Codes: G05D 21/00 Control of chemical or physico-chemical variables, e.g. pH value
• CPC Class Codes: Y10T 137/0329 Mixing of plural fluids of diverse characteristics or conditions
• CPC Class Codes: Y10T 137/2509 By optical or chemical property

Abstract

In accordance with the present invention, a microfluidic device and method of using the same is provided for self-regulating the flow of fluid therethrough. The microfluidic device includes a body defining first and second flow channels. The first flow channel has an input for receiving the fluid and an output. The second flow channel has an input for receiving a compensating fluid to modify the value of the property of the fluid and an output communicating with the first flow channel. A polymeric material is disposed in the first flow channel downstream of the output of the second flow channel. The polymeric material has a volume responsive to the value of the property of the fluid. A valve is disposed in the second flow channel and is movable in response to the volume of the material. The valve is movable between the first open position allowing the compensating fluid to flow past the valve into the first flow channel and a second closed position limiting the flow of compensating fluid therepast.

Claims

1. A microfluidic device for modifying the value of a property of a fluid, comprising:

a body defining;

a first flow channel having an input end for receiving the fluid and an output end;

a second flow channel having an input end for receiving a compensating fluid to modify the value of the property of the fluid and an output end communicating with the first flow channel;

a polymeric material positioned in the first flow channel downstream of the output end of the second flow channel and having a volume responsive to the value of the property of the fluid, the material having a first volume in response to the property having a first value and a second volume in response to the property having a second value; and

a valve disposed in the second flow channel and being movable in response to the volume of the material between a first open position allowing the compensating fluid to flow therepast into the first flow channel and a closed position limiting the flow of the compensating fluid therepast.

2. The microfluidic device of claim 1 wherein the first flow channel of the body extends along a longitudinal axis and wherein the output end of the second flow channel of the body is transverse to the longitudinal axis of first flow channel of the body.

3. The microfluidic device of claim 2 wherein the polymeric material extends along an axis transverse to the longitudinal axis of the first flow channel and parallel to the output end of the second flow channel of the body.

4. The microfluidic device of claim 1 wherein the second flow channel includes:

a first portion including the input end of the second flow channel and an output orifice; and

a second portion having an input communicating with the output orifice and including with the output end of the second flow channel.

5. The microfluidic device of claim 4 wherein the first portion of the second flow channel is generally L-shaped and has a first leg extending from the input end of the second flow channel and being generally parallel to the first flow channel and a second leg perpendicular thereto.

6. The microfluidic device of claim 4 wherein the second portion of the second flow channel is generally L-shaped and has a first leg extending from the output orifice of the first portion of the second flow channel and being generally parallel to the first flow channel and a second leg perpendicular thereto.

7. The microfluidic device of claim 4 wherein the valve includes a membrane, the membrane overlapping at least a portion of the output orifice with the valve in the closed position and the membrane spaced from the output orifice with the valve in the open position.

8. The microfluidic device of claim 7 wherein the output orifice has a generally star-shaped cross-section.

9. The microfluidic device of claim 7 wherein the membrane is integrally formed with the body.

10. The microfuidic devide of claim 1 wherein the volume of the polymeric material is pH responsive.

11. A microfluidic device for modifying the value of a property of a fluid, comprising:

a body defining;

a first flow channel extending along a longitudinal axis, the first flow channel having an input end for receiving the fluid and an output end;

a first compensating channel having an input end for receiving a compensating fluid and a second end terminating at an orifice;

a second compensating channel having an input communicatable with the orifice of the first compensating channel and an output communicating with the first flow channel;

a valve chamber extending through and communicating with the first flow chamber;

a membrane positioned within the body and isolating the valve chamber from the second compensating channel; and

a polymeric material positioned in the valve chamber downstream of the output of the second compensating channel and operatively engagable with the membrane so as to provide fluidic resistance to the flow of compensating fluid from the orifice of the first compensating channel into the second compensating channel.

12. The microfluidic device of claim 11 wherein the second compensating channel includes an end portion adjacent the output thereof and wherein the end portion of the second compensating channel is transverse to the longitudinal axis of first flow channel.

13. The microfluidic device of claim 12 wherein the polymeric material extends along an axis transverse to the longitudinal axis of the first flow channel and parallel to the end portion of the second compensating channel.

14. The microfluidic device of claim 11 wherein the first compensating channel is generally L-shaped and has a first leg extending from the input end thereof and being generally parallel to the first flow channel and a second leg perpendicular thereto.

15. The microfluidic device of claim 11 wherein the second compensating channel is generally L-shaped and has a first leg overlapping the orifice of the first compensating channel and being generally parallel to the first flow channel and a second leg perpendicular thereto.

16. The microfluidic device of claim 11 wherein the polymeric material has a volume responsive to the value of the property of the fluid, the material having a first volume in response to the property of the fluid having a first value wherein the membrane provides a first fluidic resistance to the flow of compensating fluid and a second volume in response to the property of the fluid having a second value wherein the membrane provides a second fluidic resistance to the flow of compensating fluid.

17. The microfluidic device of claim 16 wherein the volume of the polymeric material is pH responsive.

18. The microfluidic device of claim 11 wherein the output orifice has a generally star-shaped cross-section.

19. The microfluidic device of claim 11 wherein the membrane is integrally formed with the body.

20. A method for modifying the value of a property of a fluid using a microfluidic device, comprising the steps of:

providing a first flow path through the microfluidic device to accommodate the flow of the fluid therethrough;

positioning a material having a volume in the first flow path, the volume of the material responsive to the value of the property of the fluid; and

introducing a volume of a compensating fluid into the first flow path to vary the value of the property of the fluid, the volume of compensating fluid introduced varying in response to the volume of the material.

21. The method of claim 20 further comprising the step of providing a second flow path in the microfluidic device to accommodate the flow of the compensating fluid therethrough, the second flow path having first and second portions wherein the first portion communicates with the second portion through an orifice and the second portion communicates with the first flow path upstream of the material.

22. The method of claim 21 comprising the additional step of providing a material chamber in the microfluidic device transverse to and extending through the first flow path and communicating with the second flow path, the material positioned in the material chamber.

23. The method of claim 22 comprising the additional step of isolating the material from the second flow path.

24. The method of claim 23 comprising the additional step of wherein the step of isolating the material chamber from the second flow path includes the step of extending a membrane between the material chamber and the second flow path.

25. The method of claim 24 comprising the additional step of wherein the step of introducing the volume of the compensating fluid into the first flow path includes the steps:

urging the membrane over the orifice in the first portion of the second flow chamber so as to limit the flow of compensating fluid therethrough in response to the value of the property of the fluid being a first value; and

opening the orifice in the first portion of the second flow chamber so as to increase the flow of compensating fluid therethrough in response to the value of the property of the fluid being a second value.

26. The method of claim 21 wherein the volume of the compensating fluid is introduced into the first flow path a predetermined angle thereto.

27. The method of claim 26 wherein the predetermined angle is generally equally to 90 degrees.

28. The method of claim 21 wherein the compensating fluid is introduced into the first flow path such that the fluid and the compensating fluid flow in the first flow path are in a laminar arrangement.

29. The method of claim 28 comprising the additional step of engaging a portion of the material with the fluid and with the compensating fluid so as to vary the volume of the material.