ELECTROWETTING BASED DIGITAL MICROFLUIDICS

• US 20100307922A1
• Filed: 05/27/2008
• Published: 12/09/2010
• Est. Priority Date: 05/24/2007
• Status: Active Grant

• Current Assignee: Digital BioSystems, Co.
• Original Assignee: Digital BioSystems, Co.
• Inventors: Wu, Chuanyong
• Granted Patent: US 8,409,417 B2
• Time in Patent Office: Days
• US Class Current: 204/643
• CPC Class Codes: B01F 33/3021 the components to be mixed being combined in a single independent droplet, e.g. these droplets being divided by a non-miscible fluid or consisting of independent droplets
• CPC Class Codes: B01F 33/3031 using electro-hydrodynamic [EHD] or electro-kinetic [EKI] phenomena to mix or move the fluids
• CPC Class Codes: B01L 2200/0605 Metering of fluids
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0819 Microarrays; Biochips
• CPC Class Codes: B01L 2300/0864 comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
• CPC Class Codes: B01L 2300/0867 Multiple inlets and one sample wells, e.g. mixing, dilution
• CPC Class Codes: B01L 2300/089 Virtual walls for guiding liquids
• CPC Class Codes: B01L 2400/0427 Electrowetting
• CPC Class Codes: B01L 3/502792 for moving individual droplets on a plate, e.g. by locally altering surface tension

Abstract

Apparatus and methods are provided for liquid manipulation utilizing electrostatic field force. The apparatus is a single-sided electrode design in which all conductive elements are embedded on the first surface on which droplets are manipulated. An additional second surface can be provided parallel with the first surface for the purpose of containing the droplets to be manipulated. By performing electrowetting based techniques in which different electrical potential values are applied to different electrodes embedded in the first surface in a controlled manner, the apparatus enables a number of droplet manipulation processes, including sampling a continuous liquid flow by forming individually controllable droplets from the flow, moving a droplet, merging and mixing two or more droplets together, splitting a droplet into two or more droplets, iterative binary mixing of droplets to obtain a desired mixing ratio, and enhancing liquid mixing within a droplet.

Claims

1. An apparatus for liquid manipulation, comprising

(a) a substrate comprising a first substrate surface;

(b) first array of elongated drive electrodes disposed on the first substrate surface;

(c) first dielectric layer disposed on the first substrate surface to cover the first array of drive electrodes;

(d) second array of elongated drive electrodes, substantially perpendicular to the first array, disposed on the first substrate surface;

(e) second dielectric layer disposed on the first substrate surface to cover the second array of drive electrodes;

(f) an electrode selector for sequentially activating and de-activating one or more selected drive electrodes of the two arrays to sequentially bias the selected drive electrodes actuation voltages, whereby a droplet disposed on the substrate surface moves along a desired path defined by the selected drive electrodes;

2. The apparatus according to claim 1 comprising a plate spaced from the first substrate surface by a distance to define a space between the plate and the substrate surface, wherein the distance is sufficient to contain a droplet disposed in the space.

3. The apparatus according to claim 2 wherein the plate comprises a plate surface facing the first substrate surface.

4. The apparatus according to claim 3 wherein an electrode is disposed on the said plate surface.

5. The apparatus according to claim 4 wherein an electrically insulative, hydrophobic layer is disposed on the said electrode.

6. The apparatus according to claim 1 wherein at least a portion of the second dielectric layer is hydrophobic.

7. The apparatus according to claim 1, wherein the liquid is an electrolyte.

8. The apparatus according to claim 1 wherein the electrode selector comprises an electronic processor.

9. The apparatus according to claim 1 comprising a droplet inlet communicating with the surface.

10. The apparatus according to claim 9 comprising a droplet outlet communicating with the surface.

11. An apparatus for liquid manipulation, comprising

(a) a substrate comprising a first substrate surface;

(b) first array of elongated drive electrodes disposed on the substrate surface;

(c) first dielectric layer disposed on the substrate surface to cover the first array of drive electrodes;

(d) second array of elongated drive electrodes, substantially perpendicular to the first array, disposed on the substrate surface;

(e) second dielectric layer disposed on the substrate surface to cover the second array of drive electrodes;

(f) an electrode selector for sequentially activating and de-activating one or more selected drive electrodes of the two arrays to sequentially bias the selected drive electrodes to actuation voltages, whereby a droplet disposed on the substrate surface moves along a desired path defined by the selected drive electrodes;

12. The apparatus according to claim 11 wherein at least a portion of the second dielectric layer is hydrophobic.

13. The apparatus according to claim 11, wherein the liquid is an electrolyte.

14. The apparatus according to claim 11 wherein the electrode selector comprises an electronic processor.

15. The apparatus according to claim 11 comprising a droplet inlet communicating with the surface.

16. The apparatus according to claim 11 comprising a droplet outlet communicating with the surface.