Method, apparatus and article for microfluidic control via electrowetting, for chemical, biochemical and biological assays and the like

• US 7,163,612 B2
• Filed: 11/26/2002
• Issued: 01/16/2007
• Est. Priority Date: 11/26/2001
• Status: Expired due to Fees

• Current Assignee: Keck Graduate Institute
• Original Assignee: Keck Graduate Institute
• Inventors: Chen, Chao-Yi, Sterling, James D.
• Primary Examiner(s): Olsen; Kaj K.
• Application Number:
  US10/305,429
• Publication Number:
  US 20030164295A1
• Time in Patent Office: 1,512 Days
• Field of Search: 204600-604, 204643-645, 204/672, 422/82.01, 422/100, 436149-150
• US Class Current: 204/600
• CPC Class Codes: B01L 2200/06 Fluid handling related problems
• CPC Class Codes: B01L 2300/0819 Microarrays; Biochips
• 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 2400/0427 Electrowetting
• CPC Class Codes: B01L 3/502715 characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces
• 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 3/502792 for moving individual droplets on a plate, e.g. by locally altering surface tension
• CPC Class Codes: F04B 17/00 Pumps characterised by combination with, or adaptation to, specific driving engines or motors
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: G02B 26/005 based on electrowetting

Abstract

An active matrix microfluidic platform employs thin film transistor active (“TFT”) matrix liquid crystal display technology to manipulate small samples of fluid for chemical, biochemical, or biological assays without moving parts, for example, using a two-dimensional matrix array of drive electrodes. The active matrix microfluidic platform may employ existing active matrix addressing schemes and/or commercial “off-the-shelf” animation software to program assay protocols. A feedback subsystem may determine an actual location of a fluid in the microfluidic structure, and provides location information to for display, for example, on an active matrix display, and/or to control movement of one or more fluid bodies in the microfluidic structure.

Claims

1. A microfluidic platform for moving microfluidic bodies having a lateral dimension, comprising:

a plurality of drive electrodes having a dimension less than the lateral dimension of the microfluidic bodies;

a dielectric layer overlying at least a portion of the plurality of electrodes;

a plurality of thin film transistors coupled to the drive electrodes to control a respective potential to respective portions of the dielectric layer to move the fluidic bodies from a portion of the dielectric layer overlying one drive electrode to a portion of the dielectric layer overlying another drive electrode;

at least one ground line overlying at least a portion of the dielectric layer to provide a ground potential to at least one microfluidic body; and

a port providing fluid communications between an interior and an exterior of the microfluidic platform when the microfluidic platform is in use.

2. The microfluidic platform of claim 1 wherein the dimension of the electrodes is less than approximately half of the lateral dimension of the microfluidic bodies.

3. The microfluidic platform of claim 1 wherein the dimension of the electrodes is less than approximately one third of the lateral dimension of the microfluidic bodies.

4. The microfluidic platform of claim 1 wherein there are at least three drive electrodes in an area equivalent to an area that would be electrowetted by the fluid.

5. The microfluidic platform of claim 1, further comprising:

a valve for selectively closing and opening the port when the microfluidic platform is in use.

6. A microfluidic system to move at least one fluid body, comprising:

a substrate;

an array of thin film transistors;

an array of drive electrodes carried by the substrate;

a dielectric carried by the substrate, overlying at least a portion of the array of drive electrodes;

a fluid compatibility layer overlying the drive electrodes; and

at least one ground line carried by the substrate, overlying at least a portion of the dielectric to provide a ground potential to at least one fluidic body.

7. The microfluidic system of claim 6, wherein the transistors of the array of thin film transistors are electrically coupled to respective ones of the drive electrodes in the array of drive electrodes to control a respective potential applied to respective portions of the dielectric overlying the drive electrodes to move the at least one fluidic body with respect to the drive electrodes.

8. The microfluidic system of claim 7, further comprising:

a controller programmable to execute a set of driver instructions and coupled to control the transistors of the array of thin film transistors according to a set of driver instructions to supply at least one voltage from a voltage source to the drive electrodes via the transistors.

9. The microfluidic structure of claim 7 wherein the array of drive electrodes is a generally planar two-dimensional matrix, where successive drive electrodes in the array are activated to apply a different respective potential to the respective portions of the dielectric in a plane of travel of the at least one fluid body.

10. The microfluidic system of claim 6, further comprising:

at least one voltage source for supplying at least one voltage.

11. The microfluidic system of claim 6, further comprising:

a computing system; and

a computer-readable medium having a set of computer animation instructions for causing the computing system to create the set of driver instructions in response to user input.

12. The microfluidic structure of claim 6 wherein each of the drive electrodes have a dimension less than a lateral dimension of the at least one fluid body.

13. The microfluidic structure of claim 6 wherein the fluid compatibility layer is hydrophobic.

14. The microfluidic structure of claim 6 wherein an interior microfluidic structure is open to an ambient environment in use.

15. The microfluidic structure of claim 6 wherein at least a portion of the dielectric is exposed to an exterior of microfluidic structure in use.

16. A method of forming a microfluidic structure for manipulating at least one fluid body, the method comprising:

forming a substrate;

forming a dielectric carried by the substrate;

providing a first plate;

forming an array of drive electrodes overlying at least a portion of the first plate, the drive electrodes having a dimension less than a lateral dimension of the at least one fluid body;

forming an array of transistors overlying at least a portion of the first plate, the transistors electrically coupled to control the drive electrodes; and

forming a fluid compatibility layer overlying the drive electrodes; and

forming at least one ground line carried by the substrate and positioned to provide a ground potential to the at least one fluid body wherein the at least one ground line overlies at least a portion of the dielectric.

17. The method of claim 16 wherein forming an array of drive electrodes overlying at least a portion of the first plate includes forming a two-dimensional matrix array of electrodes, and wherein forming an array of transistors comprises forming a two-dimensional matrix array of thin film transistors electrically coupled to respective ones of the drive electrodes.

18. The method of claim 16 wherein forming a fluid compatibility layer overlying the array of drive electrodes comprises depositing a hydrophobic material over the array of drive electrodes, the fluid compatibility layer exposed to an exterior of the microfluidic structure during use.

19. The method of claim 16, further comprising:

forming a first fluid compatibility coating overlying the at least one ground line, the first fluid compatibility coating exposed to an exterior of the microfluidic structure during use.