Microfluidic system including a bubble valve for regulating fluid flow through a microchannel

• US 6,877,528 B2
• Filed: 06/24/2002
• Issued: 04/12/2005
• Est. Priority Date: 04/17/2002
• Status: Expired due to Term

• Current Assignee: Cytonome/St, Llc (Cytonome Inc.)
• Original Assignee: Cytonome Inc.
• Inventors: Deshpande, Manish, Böhm, Sebastian, Gilbert, John Richard
• Primary Examiner(s): CHAMBERS, A MICHAEL
• Application Number:
  US10/179,586
• Publication Number:
  US 20030196714A1
• Time in Patent Office: 1,023 Days
• Field of Search: 137/827, 137/833, 137/830, 137/831, 137/806, 137/807, 204/601
• US Class Current: 137/827
• CPC Class Codes: B01L 2200/0636 Focussing flows, e.g. to laminate flows
• CPC Class Codes: B01L 2200/0647 Handling flowable solids, e.g. microscopic beads, cells, particles
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0864 comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
• CPC Class Codes: B01L 2300/089 Virtual walls for guiding liquids
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 2400/06 Valves, specific forms thereof
• CPC Class Codes: B01L 2400/0688 surface tension valves, capillary stop, capillary break
• CPC Class Codes: B01L 2400/082 Active control of flow resistance, e.g. flow controllers
• CPC Class Codes: B01L 3/502738 characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: B01L 3/502761 specially adapted for handling suspended solids or molecules independently from the bulk fluid flow, e.g. for trapping or sorting beads, for physically stretching molecules investigating characteristics of particles G01N15/00
• CPC Class Codes: B01L 3/502776 specially adapted for focusing or laminating flows
• CPC Class Codes: B07C 5/34 Sorting according to other particular properties material testing per se G01N; quality control G07C3/14
• CPC Class Codes: F16K 2099/0074 using photolithography, e.g. etching
• 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 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 99/0017 Capillary or surface tension valves, e.g. using electro-wetting or electro-capillarity effects
• CPC Class Codes: F16K 99/0019 Valves using a microdroplet or microbubble as the valve member
• CPC Class Codes: F16K 99/0034 Operating means specially adapted for microvalves
• CPC Class Codes: F16K 99/0036 : operated by temperature variations
• CPC Class Codes: F16K 99/004 : using radiation
• CPC Class Codes: F16K 99/0046 : using magnets
• CPC Class Codes: F16K 99/0048 : using piezoelectric means
• CPC Class Codes: G01N 15/149 : specially adapted for sorting particles, e.g. by their size or optical properties
• CPC Class Codes: Y10T 137/0318 : Processes
• CPC Class Codes: Y10T 137/0396 : Involving pressure control
• CPC Class Codes: Y10T 137/0497 : Fluid actuated or retarded
• CPC Class Codes: Y10T 137/2076 : Utilizing diverse fluids
• CPC Class Codes: Y10T 137/2082 : Utilizing particular fluid
• CPC Class Codes: Y10T 137/2191 : By non-fluid energy field affecting input [e.g., transducer]
• CPC Class Codes: Y10T 137/2196 : Acoustical or thermal energy
• CPC Class Codes: Y10T 137/2202 : By movable element
• CPC Class Codes: Y10T 137/2207 : Operating at timed intervals [e.g., to produce pulses]
• CPC Class Codes: Y10T 137/2213 : Electrically-actuated element [e.g., electro-mechanical transducer]
• CPC Class Codes: Y10T 137/2224 : Structure of body of device
• CPC Class Codes: Y10T 29/49405 : Valve or choke making
• CPC Class Codes: Y10T 436/143333 : Saccharide [e.g., DNA, etc.]
• CPC Class Codes: Y10T 436/25375 : Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]

Abstract

A microfluidic system includes a bubble valve for regulating fluid flow through a microchannel. The bubble valve includes a fluid meniscus interfacing the microchannel interior and an actuator for deflecting the membrane into the microchannel interior to regulate fluid flow. The actuator generates a gas bubble in a liquid in the microchannel when a sufficient pressure is generated on the membrane.

Claims

1. A microfluidic device, comprising:

a microchannel having an interior bounded by a side wall;

a valve for regulating the flow of fluid through the microchannel, the valve comprising a gas-filled first reservoir, a fluid meniscus interfacing the reservoir and the interior and an actuator for varying the volume of the first reservoir to increase an internal pressure of the first reservoir to vary the flow of fluid through the microchannel; and

a second reservoir for absorbing a pressure variation in the microchannel induced by the actuator.

2. The microfluidic device of claim 1, wherein the actuator deflects the meniscus into the microchannel interior to regulate the flow of fluid through the microchannel.

3. The microfluidic device of claim 1, wherein the meniscus comprises a virtual wall formed in an aperture in the side wall of the microchannel when the microchannel is filled with a liquid.

4. The microfluidic device of claim 1, wherein the actuator generates a gas bubble in the microchannel.

5. The microfluidic device of claim 4, further comprising a hydrophobic patch attached to an inner wall of the microchannel for anchoring the gas bubble.

6. The microfluidic device of claim 4, wherein the microchannel defines a cavity for retaining the gas bubble.

7. The microfluidic device of claim 1, wherein the gas filled first reservoir comprises a movable membrane.

8. The microfluidic device of claim 7, wherein the actuator deflects the movable membrane to create a bubble in the microchannel interior.

9. A microfluidic device comprising:

a first plate having a groove formed therein defining a microchannel;

a second plate for enclosing the microchannel bonded to the first plate having a first aperture formed on a first side of the groove sized and dimensioned to form a meniscus when the microchannel is filled with a liquid, the first aperture defining a first reservoir adjacent to the microchannel, wherein the meniscus forms an interface between the microchannel and the reservoir and a second reservoir formed on a second side of the groove opposite the first reservoir for absorbing pressure variations in the groove; and

a flexible membrane bonded to the second plate to seal the first reservoir.

10. The microfluidic device of claim 9, further comprising an actuator for deflecting the flexible membrane, wherein the deflection of the membrane increases the pressure in the reservoir and deflects the meniscus into the microchannel to regulate liquid flow therethrough.

11. The microfluidic device of claim 10, wherein the actuator comprises one of an electromagnetic element and a piezoelectric element.

12. The microfluidic device of claim 9, further comprising a hydrophobic patch attached to the groove.

13. The microfluidic device of claim 9, wherein the meniscus forms a bubble in the microchannel to block liquid flow.

14. The microfluidic device of claim 13, wherein the groove includes a cavity formed therein for retaining the bubble.

15. A microfluidic device, comprising:

a microchannel having an interior bounded by a side wall;

a first bubble valve for creating and injecting a bubble into the microchannel interior to regulate fluid flow through the microchannel;

a buffer in communication with the microchannel for absorbing a pressure variation in the microchannel caused by the bubble; and

a hydrophobic patch for retaining the bubble in a predetermined position in the microchannel interior.

16. The microfluidic device of claim 15, wherein the bubble valve comprises an aperture in the side wall, wherein a fluid in the microchannel forms a meniscus in the aperture, a sealed chamber formed adjacent to the aperture and an actuator for deflecting the meniscus into the interior by increasing the pressure in the chamber.

17. In a particle sorting device a bubble valve for separating particles having a predetermined characteristic from particles not having a predetermined characteristic, the bubble valve comprising:

a first gas-filled reservoir;

a channel in communication with a channel through which a stream of particles in a carrier fluid passes, wherein the carrier fluid forms a meniscus in the side channel adjacent to the gas-filled reservoir;

an actuator for deflecting the meniscus to create a pressure pulse to selectively deflect a particle having the predetermined characteristic from the stream of particles; and

a second reservoir for absorbing the pressure pulse.

18. A microfluidic device, comprising:

a channel for conveying a stream of particles in a carrier fluid;

an actuator for selectively applying a pressure pulse to the stream to deflect a particle in the stream of particles from the stream of particles; and

a buffer for absorbing the pressure pulse.

19. The device of claim 18, wherein the channel comprises an inlet, a first outlet and a second outlet, wherein the particles normally flow from the inlet into the first outlet.

20. The device of claim 19, wherein the pressure pulse deflects a particle in the stream of particles into the second outlet when a predetermined characteristic of the particle is detected.

21. The device of claim 18, further comprising a sensor for sensing a predetermined characteristic in a particle.

22. A microfluidic device, comprising:

a primary channel for conveying a stream of particles in a carrier fluid;

a first side channel in communication with the primary channel;

an actuator connected to the first side channel for applying a pressure pulse to the stream of particles to deflect a particle in the stream of particles from the stream of particles;

a second side channel in communication with the side channel; and

a buffer in communication with the second side channel for absorbing the pressure pulse.

23. The microfluidic device of claim 22, wherein the actuator comprises a flexible membrane.

24. The microfluidic device of claim 22, wherein the buffer comprises a flexible membrane.

25. The microfluidic device of claim 22, wherein the actuator comprises air trapped in a sealed reservoir.

26. The microfluidic device of claim 22, wherein the buffer comprises air trapped in a sealed reservoir.