Microfabricated elastomeric valve and pump systems

• US 20050166980A1
• Filed: 02/10/2005
• Published: 08/04/2005
• Est. Priority Date: 06/28/1999
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Unger, Marc A., Chou, Hou-Pu, Scherer, Axel, Quake, Stephen R., Thorsen, Todd A., Hansen, Carl L., Adams, Mark L., Enzelberger, Markus M.
• Granted Patent: US 7,216,671 B2
• Time in Patent Office: Days
• US Class Current: 137/833
• CPC Class Codes: B01J 2219/00355 peristaltic
• CPC Class Codes: B01J 2219/00378 Piezoelectric or ink jet dispensers
• CPC Class Codes: B01J 2219/00396 Membrane valves
• CPC Class Codes: B01J 2219/00398 in multiple arrangements
• CPC Class Codes: B01J 2219/00439 using micromirror arrays
• CPC Class Codes: B01J 2219/005 Beads
• CPC Class Codes: B01J 2219/00527 Sheets
• CPC Class Codes: B01J 2219/00605 the compounds being directly bound or immobilised to solid supports
• CPC Class Codes: B01J 2219/00612 the surface being inorganic
• CPC Class Codes: B01J 2219/00621 by physical means, e.g. trenches, raised areas
• CPC Class Codes: B01J 2219/00659 Two-dimensional arrays
• CPC Class Codes: B01J 2219/00707 separated from the reactor apparatus
• CPC Class Codes: B01J 2219/00722 Nucleotides
• CPC Class Codes: B01J 2219/00725 Peptides
• CPC Class Codes: B01L 2200/025 Align devices or objects to ensure defined positions relative to each other
• CPC Class Codes: B01L 2200/027 for microfluidic devices
• CPC Class Codes: B01L 2200/0605 Metering of fluids
• CPC Class Codes: B01L 2200/10 Integrating sample preparation and analysis in single entity, e.g. lab-on-a-chip concept
• CPC Class Codes: B01L 2300/0681 Filter
• CPC Class Codes: B01L 2300/0861 Configuration of multiple channels and/or chambers in a single devices
• CPC Class Codes: B01L 2300/0887 : Laminated structure
• CPC Class Codes: B01L 2300/123 : Flexible; Elastomeric
• CPC Class Codes: B01L 2300/14 : Means for pressure control
• CPC Class Codes: B01L 2300/18 : Means for temperature control
• CPC Class Codes: B01L 2400/046 : Chemical or electrochemical formation of bubbles
• CPC Class Codes: B01L 2400/0481 : squeezing of channels or chambers
• CPC Class Codes: B01L 2400/06 : Valves, specific forms thereof
• CPC Class Codes: B01L 2400/0655 : pinch valves
• CPC Class Codes: B01L 2400/0688 : surface tension valves, capillary stop, capillary break
• CPC Class Codes: B01L 3/502707 : characterised by the manufacture of the container or its components by shaping or joining plastic parts B29C59/00, B29C65/00; by laminating B32B37/00; manufacture of microstructural devices in general B81C
• 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: B01L 3/502738 : characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: B01L 7/54 : using spatial temperature gradients
• CPC Class Codes: B01L 9/527 : for microfluidic devices, e.g. used for lab-on-a-chip
• CPC Class Codes: B05D 3/04 : by exposure to gases
• CPC Class Codes: B32B 2037/1081 : using a magnetic force
• CPC Class Codes: B65B 31/00 : Packaging articles or materials under special atmospheric or gaseous conditions; Adding propellants to aerosol containers
• CPC Class Codes: B81B 2201/036 : Micropumps
• CPC Class Codes: B81B 2201/054 : Microvalves
• CPC Class Codes: B81C 1/00119 : Arrangement of basic structures like cavities or channels, e.g. suitable for microfluidic systems
• CPC Class Codes: B81C 2201/019 : Bonding or gluing multiple substrate layers
• CPC Class Codes: C12Q 1/6832 : Enhancement of hybridisation reaction
• CPC Class Codes: C12Q 1/6874 : involving nucleic acid arrays, e.g. sequencing by hybridisation
• CPC Class Codes: C12Q 2535/125 : Allele specific primer extension
• CPC Class Codes: C30B 29/54 : Organic compounds
• CPC Class Codes: F04B 43/043 : Micropumps
• CPC Class Codes: F04B 43/14 : having plate-like flexible members
• CPC Class Codes: F15C 1/06 : Constructional details; Selection of specified materials ; Constructional realisation of one single element; Canal shapes; Jet nozzles; Assembling an element with other devices, only if the element forms the main part F15C5/00 takes precedence
• CPC Class Codes: F15C 3/00 : Circuit elements having moving parts valves, construction of valves F16K
• 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 2099/0076 : using electrical discharge machining [EDM], milling or drilling
• CPC Class Codes: F16K 2099/0078 : using moulding or stamping
• CPC Class Codes: F16K 2099/008 : Multi-layer fabrications
• CPC Class Codes: F16K 2099/0084 : Chemistry or biology, e.g. "lab-on-a-chip" technology
• CPC Class Codes: F16K 2099/0094 : Micropumps
• 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 99/0015 : Diaphragm or membrane valves
• CPC Class Codes: F16K 99/0046 : using magnets
• CPC Class Codes: F16K 99/0051 : using electrostatic means
• CPC Class Codes: F16K 99/0059 : actuated by a pilot fluid
• CPC Class Codes: Y10T 137/0324 : With control of flow by a condition or characteristic of a fluid
• CPC Class Codes: Y10T 137/0379 : By fluid pressure
• CPC Class Codes: Y10T 137/0424 : Liquid cleaning or flushing
• CPC Class Codes: Y10T 137/206 : Flow affected by fluid contact, energy field or coanda effect [e.g., pure fluid device or system]
• CPC Class Codes: Y10T 137/2082 : Utilizing particular fluid
• CPC Class Codes: Y10T 137/2164 : Plural power inputs to single device
• CPC Class Codes: Y10T 137/2169 : Intersecting at interaction region [e.g., comparator]
• CPC Class Codes: Y10T 137/2174 : Co-lineal, oppositely-directed power inputs [e.g., impact modulator]
• CPC Class Codes: Y10T 137/2202 : By movable element
• CPC Class Codes: Y10T 137/2224 : Structure of body of device
• CPC Class Codes: Y10T 137/3084 : Discriminating outlet for gas
• CPC Class Codes: Y10T 137/7837 : Direct response valves [i.e., check valve type]
• CPC Class Codes: Y10T 137/86027 : Electric
• CPC Class Codes: Y10T 156/10 : Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 428/24479 : including variation in thickness
• CPC Class Codes: Y10T 428/24612 : Composite web or sheet

Abstract

A method of fabricating an elastomeric structure, comprising: forming a first elastomeric layer on top of a first micromachined mold, the first micromachined mold having a first raised protrusion which forms a first recess extending along a bottom surface of the first elastomeric layer; forming a second elastomeric layer on top of a second micromachined mold, the second micromachined mold having a second raised protrusion which forms a second recess extending along a bottom surface of the second elastomeric layer; bonding the bottom surface of the second elastomeric layer onto a top surface of the first elastomeric layer such that a control channel forms in the second recess between the first and second elastomeric layers; and positioning the first elastomeric layer on top of a planar substrate such that a flow channel forms in the first recess between the first elastomeric layer and the planar substrate.

Claims

1. A fluidic logic device comprising:

an elastomeric block; and

a plurality of microfabricated channels formed in the elastomeric block, each channel containing a pressure or flow representing a signal, a change in the pressure or flow in a first channel resulting in a change in the pressure or fluid flow in a second channel consistent with a logic operation.

2. The device of claim 1, where the change in pressure or flow in the second channel is nonlinear with respect to the pressure or fluid flow changes in the first channel.

3. The device of claim 1 wherein a one way valve is positioned in at least one of the first channel and the second channel.

4. The device of claim 3 wherein:

the second channel comprises an inlet in communication with an outlet through a flow restrictor, the second channel including a junction upstream of the flow restrictor; and

the first channel comprises at least two control channels connected at the junction through one-way valves, such that pressures of the control channels are reflected at the outlet consistent with an AND-type truth table.

5. The device of claim 1 wherein:

the second channel comprises an inlet portion and an outlet portion; and

the first channel comprises at least two control channels adjacent to the first channel and separated from the first channel by respective first and second elastomer membranes, such that application of pressures to the control channels deflects at least one of the first and second membranes into the flow channel to reflect a pressure at the outlet consistent with a NOR-type truth table.

6. The device of claim 1 wherein:

the second channel comprises first and second inlet portions that merge to form an outlet portion; and

the first channel comprises first and second control channels adjacent to the first and second inlet portions, the first control channel separated from the first and second inlet portions by respective first and second membranes, and the second control channel separated from the first and second portions by respective third and fourth membranes, such that application of control pressures to the first and second control channels deflects at least one of the first, second, third, and fourth membranes into the first and second inlet portions to reflect a pressure at the outlet consistent with a NOR-type truth table.

7. The device of claim 6 further comprising an amplification structure positioned between the first channel and at least one of the first, second, third, and fourth membranes.

8. The device of claim 1 wherein an outlet of the second channel is in fluid communication with a first channel of a second fluidic logic device.

9. A pressure amplifier comprising:

an elastomeric block formed with first and second microfabricated recesses therein; and

an amplifier structure having a first surface area in contact with the first recess and a second surface area in contact with the second recess, the first surface area larger than the second surface area such that a pressure in the first recess is communicated by the amplifier structure as an amplified pressure to the second recess.

10. The pressure amplifier of claim 9 wherein the first recess comprises a control channel.

11. The pressure amplifier of claim 9 wherein the second recess comprises a flow channel.

12. The pressure amplifier of claim 9 wherein the amplifier structure is a rectangular pyramid.

13. The pressure amplifier of claim 9 wherein the amplifier structure is a cone.

14. A method of amplifying a pressure in a flow channel of a microfabricated elastomer structure, the method comprising:

providing an elastomer block including a first recess in contact with a first area of an amplifier structure and second recesses in contact with a second area of the amplifier structure;

applying a pressure to the first area; and

communicating the pressure to the second area, the second area smaller than the first area such that the pressure communicated to the second recess is amplified.

15. The method of claim 14 wherein the first recess is a control channel and the pressure is applied by pressurization of the control channel.

16. The method of claim 14 wherein the second recess is a flow channel and the amplified pressure is employed to control a flow of fluid through the flow channel.

19. The one-way valve of claim 14 wherein the flap is prevented from moving in a second direction opposite the first direction by a protuberance on a wall of the channel.

20. The one-way valve of claim 19 wherein the protuberance affords a portion of the channel a narrower cross section than the flap.

17. A one-way valve comprising a microfabricated channel formed in an elastomeric block, a flap integral with the elastomeric block projecting into the channel and blocking the channel, the flap deflectable to permit fluid to flow in only a first direction.

18. The one-way valve of claim 17 wherein the flap is integral with a ceiling portion of the channel.

21. A method of filling a microfabricated elastomeric structure with fluid comprising:

providing an elastomer block having a flow channel, the elastomer block comprising an elastomer material known to be permeable to a gas;

filling the flow channel with the gas;

injecting a fluid under pressure into the flow channel; and

permitting gas remaining in the flow channel to diffuse out of the elastomer material.

22. The method of claim 21 wherein the elastomer is a silicone elastomer and the gas is air.

23. A method of metering a volume of fluid comprising:

providing a chamber having a volume in an elastomeric block separated from a control recess by an elastomeric membrane;

supplying a pressure to the control recess such that the membrane is deflected into the chamber and the volume is reduced by a calibrated amount, thereby excluding from the chamber the calibrated volume of fluid.

24. The method of claim 23 wherein the calibrated volume of fluid is provided to a further microfluidic system.

25. The method of claim 23 further comprising:

providing a second fluid to an opening of the chamber; and

ceasing application of the pressure such that the membrane relaxes back to an original position and the calibrated volume of the second fluid is drawn into the chamber.

26. The method of claim 25 wherein the first fluid is a protein solution and the second fluid is a countersolvent, such that drawing the second fluid into the chamber changes a solubility of the protein.

27. The method of claim 26 further comprising the parallelization of multiple chambers with varying calibrated volumes.

28. The method of claim 26 further comprising the use of a parallel structure to rapidly determine optimal conditions for protein crystallization.

29. A protein crystallization system comprising:

an elastomeric block including a microfabricated chamber having a volume and receiving a protein solution; and

a microfabricated flow channel in fluid communication with the chamber, the flow channel receiving a countersolvent and introducing a fixed volume of countersolvent to the chamber.

30. The protein crystallization system of claim 29 comprising an isolation structure, the isolation structure configured to selectively isolate the chamber from the flow channel as the flow channel receives the a predetermined volume of countersolvent, and then to place the chamber into contact with the flow channel.

31. The protein crystallization system of claim 29 comprising a control channel overlying the chamber and separated from the chamber by a membrane, the membrane deflectable into the chamber to exclude a calibrated volume of protein solution, such that relaxation of the membrane draws the calibrated volume of the countersolvent into the chamber.

32. A method of promoting adhesion between layers of a microfabricated structure, the method comprising:

exposing a surface of a first component layer to a chemical;

exposing a surface of a second component layer to the chemical; and

placing the surface of the first component layer into contact with the surface of the second elastomer layer.

33. The method of claim 32 wherein the first and second component layers comprise silicone elastomers and the chemical comprises ethanol.

34. The method of claim 33 wherein the component layers are dried before being placed into contact.

35. The method of claim 32 wherein the first component layer comprises an elastomer and the second component layer comprises a glass substrate, the first and second component layers exposed to ethanol and dried before being placed into contact.

36. A method for actuating a microfabricated elastomer structure comprising:

providing an aqueous salt solution in a control recess formed in an elastomeric block and overlying and separated from a flow channel by an elastomer membrane; and

applying a potential difference to the salt solution to generate a gas, such that a pressure in the control recess causes the membrane to deflect into the flow channel.

37. The method of claim 36 wherein the gas diffuses out of the elastomeric block to permit the membrane to relax out of the flow channel.

38. The method of claim 36 wherein the gas is mechanically vented to permit the membrane to relax out of the flow channel.

39. A microfabricated syringe structure comprising:

a first chamber formed in an elastomeric block and including an aqueous salt solution, a first electrode, and a second electrode;

a second chamber formed in the elastomeric block and containing an inert liquid, the second chamber in fluid communication with the first chamber through a first flow channel;

a third chamber formed in the elastomeric block and containing an ejectable material, the third chamber in fluid communication with the second chamber through a second flow channel and in fluid communication with an environment through an outlet, such that application of a potential difference across the electrodes generates gas in the first chamber, the gas displacing the inert material into the third chamber, the inert material displacing the injectable material into the environment.

40. A method of fabricating an elastomeric structure comprising:

cutting the first elastomer structure along a vertical section to form a first elastomer portion and a second elastomer portion; and

bonding the first elastomer structure to another component.

41. The method of claim 40 wherein the first elastomer layer is of a first type and the second elastomer layer is of a second type complementary to the first type, the method further comprising:

forming a second elastomer structure;

cutting the second elastomer structure along a vertical section to form a third elastomer portion and a fourth elastomer portion; and

bonding the first elastomer portion to the third elastomer portion to form a third elastomer structure.

42. The method of claim 41 wherein the third elastomer portion is of the second type and the fourth elastomer portion is of the first type.

43. The method of claim 40 wherein the other component is a membrane, and further comprising bonding a second elastomer structure to an opposite side of the membrane than the first elastomer structure is bonded to.