AUTONOMOUS ELECTROCHEMICAL ACTUATION OF MICROFLUIDIC CIRCUITS

• US 20090260692A1
• Filed: 01/06/2009
• Published: 10/22/2009
• Est. Priority Date: 01/11/2008
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: WALAVALKAR, Sameer, Scherer, Axel
• Granted Patent: US 8,100,672 B2
• Time in Patent Office: Days
• US Class Current: 137/13
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0874 Three dimensional network
• CPC Class Codes: B01L 2300/10 Means to control humidity and/or other gases
• CPC Class Codes: B01L 2300/1827 using resistive heater
• CPC Class Codes: B01L 2400/0421 electrophoretic flow
• CPC Class Codes: B01L 2400/046 Chemical or electrochemical formation of bubbles
• 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: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: Y10T 137/0391 Affecting flow by the addition of material or energy
• CPC Class Codes: Y10T 137/2191 By non-fluid energy field affecting input [e.g., transducer]
• 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 29/494 Fluidic or fluid actuated device making
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

A microfluidic structure with an electrically controlled pressure source is shown. The pressure source is an electrolyte connected with electrodes. Dissociation of the electrolyte generates the pressure, which is used to obtain a valve-like or pump-like behavior inside the microfluidic structure. A process for manufacturing the microfluidic structure and a method to circulate fluids in a microfluidic channel are also described.

Claims

1. A microfluidic structure comprising:

control layers comprising control channels;

fluidic layers comprising microfluidic channels, the microfluidic channels adapted to be controlled by the control channels; and

a pressure source comprising an electrolyte adapted to be electrolitically dissociated in one or more fluids, the pressure source fluidically connected with at least one control channel,

wherein, upon electrolytic dissociation of the electrolyte, the one or more fluids travel along the at least one control channel to control the microfluidic channels.

2. The microfluidic structure of claim 1, wherein the pressure source further comprises electrodes connected with the electrolyte, dissociation of the electrolyte in the one or more fluids occurring upon generation of current in the electrodes.

3. The microfluidic structure of claim 1, wherein the one or more fluids are gases.

4. The microfluidic structure of claim 1, wherein the electrolyte is water and the one or more fluids are oxygen and hydrogen.

5. The microfluidic structure of claim 1, wherein the electrolyte is sodium sulfate and the one or more fluids are oxygen.

6. The microfluidic structure of claim 1, wherein control of the microfluidic channels by the one or more fluids travelling along the at least one control channel occurs through movement of membrane regions separating the control channels from the microfluidic channels.

7. The microfluidic structure of claim 1, wherein the pressure source is located in a chamber fluidically connected with the at least one control channel.

8. The microfluidic structure of claim 1, further comprising:

a further pressure source comprising a further fluid wherein, upon the electrolytic dissociation of the electrolyte, the one or more fluids exercise pressure on the further fluid which, in turn, generates a pumping effect on the microfluidic channels.

9. The microfluidic structure of claim 8, wherein the further pressure source is located in a microfluidic channel, the microfluidic channel fluidically connected with the control channel in which the one or more fluids are adapted to travel upon the electrolytic dissociation of the electrolyte.

10. The microfluidic structure of claim 8, further comprising a mirror pressure source and a further mirror pressure source, the combination of the pressure source, further pressure source, mirror pressure source and further mirror pressure source adapted to provide the microfluidic structure with a bidirectional pumping effect.

11. A process for manufacturing a microfluidic structure containing a pressure source, comprising:

forming electrodes;

forming microfluidic chambers and microfluidic channels;

positioning the electrodes in a microfluidic chamber of the formed microfluidic chambers;

locating an electrolyte in the microfluidic chamber, the electrolyte contacting the electrodes and acting as a pressure source upon dissociation of the electrolyte into one or more fluids when current passes through the electrodes; and

connecting the microfluidic chamber with at least one microfluidic channel of the microfluidic channels.

12. The process of claim 11, wherein the microfluidic chamber is connected with the at least one microfluidic chamber of the microfluidic chambers in a valve arrangement.

13. The process of claim 11, wherein the microfluidic chamber is connected with the at least one microfluidic chamber of the microfluidic chambers in a pumping arrangement.

14. A method to circulate at least one between oxygen and hydrogen in a microfluidic channel, comprising:

locating electrically controlled water inside a chamber of a microfluidic circuit comprising the microfluidic channel;

fluidically connecting the chamber with the microfluidic channel; and

electrolitically dissociating the water into oxygen and hydrogen, whereby at least one of oxygen and hydrogen circulates in the microfluidic channel.

15. The method of claim 14, wherein hydrogen is separated from oxygen.

16. The method of claim 15, wherein the at least one of hydrogen and oxygen circulating in the microfluidic channel is hydrogen.

17. The method of claim 14, wherein the electrically controlled water comprises electrodes contacting the water.

18. The method of claim 14, wherein the at least one of oxygen and hydrogen circulates in the microfluidic channel to control fluid circulation.

19. The method of claim 18, wherein control occurs in a valve-like behavior.

20. The method of claim 18, wherein control occurs in a pump-like behavior.