Methods for manipulating droplets by electrowetting-based techniques

• US 7,569,129 B2
• Filed: 03/10/2005
• Issued: 08/04/2009
• Est. Priority Date: 09/24/2002
• Status: Expired due to Fees

• Current Assignee: Duke University
• Original Assignee: Advanced Liquid Logic, Inc. (Illumina Incorporated)
• Inventors: Ren, Hong, Pamula, Vamsee K., Paik, Philip Y., Pollack, Michael G., Fair, Richard B.
• Primary Examiner(s): Olsen; Kaj K
• Application Number:
  US11/077,569
• Publication Number:
  US 20060054503A1
• Time in Patent Office: 1,608 Days
• Field of Search: 204/450, 204/600, 204/672
• US Class Current: 204/450
• CPC Class Codes: B01F 31/65 the materials to be mixed being directly submitted to a pulsating movement, e.g. by means of an oscillating piston or air column
• 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: B01F 33/30351 using hydrophilic/hydrophobic surfaces
• CPC Class Codes: B01L 2200/06 Fluid handling related problems
• 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 2300/089 Virtual walls for guiding liquids
• CPC Class Codes: B01L 2300/161 Control and use of surface tension forces, e.g. hydrophobic, hydrophilic
• CPC Class Codes: B01L 2300/165 Specific details about hydrophobic, oleophobic surfaces
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 2400/0427 Electrowetting
• CPC Class Codes: B01L 3/00 Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• 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 3/502784 specially adapted for droplet or plug flow, e.g. digital microfluidics automatic analysis using a stream of discrete samples in a tube system G01N35/08
• CPC Class Codes: B01L 3/502792 for moving individual droplets on a plate, e.g. by locally altering surface tension
• CPC Class Codes: B41J 2002/14395 Electrowetting
• CPC Class Codes: C25B 9/00 Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
• CPC Class Codes: G01N 27/44791 Microapparatus sample containers with integrated microfluidic structures B01L3/5027
• CPC Class Codes: G02B 26/005 : based on electrowetting

Abstract

Methods are provided for manipulating droplets. The methods include providing the droplet on a surface comprising an array of electrodes and a substantially co-planer array of reference elements, wherein the droplet is disposed on a first one of the electrodes, and the droplet at least partially overlaps a second one of the electrodes and an intervening one of the reference elements disposed between the first and second electrodes. The methods further include activating the first and second electrodes to spread at least a portion of the droplet across the second electrode and deactivating the first electrode to move the droplet from the first electrode to the second electrode.

Claims

1. A method for splitting a starting droplet into two or more droplets, comprising the steps of:

(a) providing a starting droplet on a surface of a substrate, the substrate comprising an array of drive electrodes and an array of reference elements, wherein the drive electrode array comprises at least three drive electrodes comprising a first outer drive electrode, a medial drive electrode adjacent to the first outer drive electrode, and a second outer drive electrode adjacent to the medial drive electrode, and the starting droplet is initially disposed on at least one of the three drive electrodes and is adjacent to at least one other of the three drive electrodes;

(b) biasing each of the three drive electrodes to position the starting droplet across the three drive electrodes and grounding or referencing the starting droplet using the reference elements; and

(c) biasing the medial drive electrode to split the starting droplet into first and second split droplets, whereby the first split droplet is disposed on the first outer drive electrode and the second split droplet is disposed on the second outer drive electrode.

2. The method according to claim 1 wherein the biasing step of step (b) comprises selectively biasing the three drive electrodes to a drive voltage, and the biasing step of step (c) comprises biasing the medial drive electrode to a different voltage from the drive voltage.

3. The method according to claim 1 comprising the step of using an electrode selector to control the biasing steps.

4. The method according to claim 3 wherein the electrode selector comprises an electronic processor.

5. The method according to claim 1 wherein the starting droplet is split into first and second split droplets of approximate equal volume proportions.

6. The method according to claim 1 wherein the starting droplet is split into first and second split droplets of approximate differing volume proportions.

7. A method for splitting a starting droplet into two or more split droplets, comprising the steps of:

(a) providing a starting droplet on a surface of a substrate, the substrate comprising an array of drive electrodes and an array of reference elements, wherein the drive electrode array comprises at least three drive electrodes comprising a first outer drive electrode, a medial drive electrode adjacent to the first outer drive electrode, and a second outer drive electrode adjacent to the medial drive electrode, and the starting droplet is initially disposed on at least one of the three drive electrodes and is adjacent to at least one other of the three drive electrodes;

(b) biasing the medial drive electrode to position the starting droplet and grounding or referencing the starting droplet using the reference elements, whereby the starting droplet at least partially overlaps the three drive electrodes; and

(c) biasing the medial drive electrode and at least one of the first and second outer drive electrodes to split the starting droplet into first and second split droplets, whereby the first split droplet is disposed on the first outer drive electrode and the second split drive droplet is disposed on the second outer electrode.

8. The method according to claim 7 wherein the biasing step of element (b) comprises selectively biasing the medial drive electrode to a drive voltage, and the biasing step of element (c) comprises de-coupling the medial electrode from the drive voltage.

9. The method according to claim 7 comprising the step of using an electrode selector to control the biasing steps.

10. The method according to claim 9 wherein the electrode selector comprises an electronic processor.

11. The method according to claim 7 wherein the starting droplet is split into first and second split droplets of approximate equal volume proportions.

12. The method according to claim 7 wherein the starting droplet is split into first and second split droplets of approximate differing volume proportions.