Low power integrated pumping and valving arrays for microfluidic systems

• US 20030057391A1
• Filed: 09/21/2001
• Published: 03/27/2003
• Est. Priority Date: 09/21/2001
• Status: Active Grant

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Rose, Klint A., Krulevitch, Peter A., Benett, William J., Hamilton, Julie, Maghribi, Mariam
• Granted Patent: US 7,025,323 B2
• Time in Patent Office: Days
• US Class Current: 251/11
• CPC Class Codes: F15C 5/00 Manufacture of fluid circuit elements; Manufacture of assemblages of such elements integrated circuits
• CPC Class Codes: F16K 2099/0074 using photolithography, e.g. etching
• CPC Class Codes: F16K 2099/0078 using moulding or stamping
• CPC Class Codes: F16K 2099/0084 Chemistry or biology, e.g. "lab-on-a-chip" technology
• CPC Class Codes: F16K 99/0001 Microvalves microdevices B81B1/00; manufacture or treatment of devices or systems in or on a substrate B81C1/00; microfluidic structures B01L3/5027; micropumps F04B19/006
• CPC Class Codes: F16K 99/0011 Gate valves or sliding valves
• CPC Class Codes: F16K 99/0015 Diaphragm or membrane valves
• CPC Class Codes: F16K 99/0044 using thermo-electric means
• CPC Class Codes: F16K 99/0048 using piezoelectric means
• CPC Class Codes: F16K 99/0059 actuated by a pilot fluid
• CPC Class Codes: F16K 99/0061 actuated by an expanding gas or liquid volume

Abstract

Low power integrated pumping and valving arrays which provide a revolutionary approach for performing pumping and valving approach for performing pumping and valving operations in microfabricated fluidic systems for applications such as medical diagnostic microchips. Traditional methods rely on external, large pressure sources that defeat the advantages of miniaturization. Previously demonstrated microfabrication devices are power and voltage intensive, only function at sufficient pressure to be broadly applicable. This approach integrates a lower power, high-pressure source with a polymer, ceramic, or metal plug enclosed within a microchannel, analogous to a microsyringe. When the pressure source is activated, the polymer plug slides within the microchannel, pumping the fluid on the opposite side of the plug without allowing fluid to leak around the plug. The plugs also can serve as microvalves.

Claims

1. In a microfluidic system having at least one microchannel, the improvement comprising:

a pressure generation device, having a fluid driven member, and operatively connected to said at least one microchannel, said device having functions selected from the groups consisting of pumping and valving.

2. The improvement of claim 1, wherein said fluid driven member of said pressure generation device is constructed to prevent leakage of fluid thereby.

3. The improvement of claim 1, wherein said pressure generation device includes a pressure generating chamber, a fluid, means for heating said fluid, and said fluid driven member.

4. The improvement of claim 1, wherein said pressure generation device is located in one end of said at least one microchannel.

5. The improvement of claim 1, wherein said thermopneumatic device is located in a microchannel transverse to said at least one microchannel.

6. The improvement of claim 1, wherein said thermopneumatic device additionally includes a quantity of contained fluid and means for heating said contained fluid, whereby heating of said contained fluid causes movement of said fluid driven member.

7. The improvement of claim 1, wherein said fluid driven member includes a section of reduced cross-section, whereby upon activation said thermopneumatic device said fluid driven member is moved such that fluid flowing in said at least one microchannel flow across said section of reduced cross section.

8. The improvement of claim 1, wherein said thermopneumatic device operates as a pump and includes:

a pressure generating chamber

a fluid contained in said pressure generating chamber,

said fluid driven member, and

means for heating said fluid causing movement of solid fluid driven member.

9. The improvement of claim 8, wherein said thermopneumatic device is located in a section of said at least one microchannel, and wherein movement of said fluid driven member cause movement of fluid located in said microchannel.

10. The improvement of claim 8, wherein said means for heating said fluid comprises a resistive heater.

11. The improvement of claim 1, wherein said thermopneumatic device operates as a valve and is located in a microchannel which forms a T-configuration with said at least one microchannel.

12. The improvement of claim 1, wherein said thermopneumatic device operates as a valve and is located in a microchannel which extends across said at least one microchannel, and wherein said fluid driven member includes a region of reduced cross-section, whereby variable movement of said fluid driven member results in a variable control of fluid flowing in said at least one microchannel and past said region of reduced cross-section.

21. The improvement of claim 1, wherein said pressure generation device is selected from the groups of devices consisting of thermopneumatic, electro osmotic, electrokinetic, solid-liquid phase transformation, piezoelectric, magnetic, shape memory alloy membrane, external pressure and electrochemical.

22. The improvement of claim 21, wherein said pressure generation device comprises of a thermopneumatic device.

23. The microfluidic system of claim 1, having an array of microchannels, each of said microchannel being provided with a pressure generation device,

said pressure generation devices being controlled to actuate independently to inject different fluids, to inject the same fluids, to control total dose, or total fluid injection over time.

24. The microfluidic system of claim 23, additionally including at least one microneedle located at an end of at least one of said microchannels.

25. The microfluidic system of claim 23, wherein said array of microchannels are formed by method which includes positioning wires at a desired location, molding a substrate material around the wires, and removing the wires thereby forming microchannels in the substrate.

26. The microfluidic system of claim 25, wherein said substrate is formed of polydimethyl (siloxane)

27. The microfluidic system of claim 1, wherein at least one of said pressure generation devices comprising an piezoelectric device embedded in a polymer material.

13. A microfluidic system having low power integrated pumping and valving assays located in microchannels of said system each said pumping and valving arrays including a plurality of thermopneumatic devices.

14. The microfluidic system of claim 13, wherein each of said plurality of thermopneumatic devices includes:

a pressure generating chamber

a fluid contained in said chamber by a movable member, and

means for heating said fluid causing movement of said movable member, and

movement of said movable member of any or all of said thermoneumatic devices causing pumping of or control of fluid in any or all of said microchannels.

15. The microfluidic system of claim 14, wherein said means for heating said fluid comprises a resistive heating element.

16. The microfluidic system of claim 14, wherein said means for heating said fluid produces at least a bubble in said fluid or thermal expansion of said fluid causing movement of said movable member.

17. The microfluidic system claim 14, wherein at least certain of said thermopneumatic devices are located in sections of said microchannels, whereby movement of said movable member causes a pumping action on fluid located in said microchannels.

18. The microfluidic system of claim 14, wherein at least certain of said thermopneumatic devices are located in channels located transverse of said microchannel, whereby movement of movable member causes a valving action on fluid directed through said microchannels.

19. A low power thermopneumatic device constructed to be located in or transverse to a fluidic microchannel for pumping or controlling fluid in said fluidic microchannel.

20. The thermopneumatic device of claim 19, comprising a thermopneumatic chamber, a fluid contained in said chamber, a movable member, and means for heating said fluid.