Apparatus for manipulating droplets

• US 8,221,605 B2
• Filed: 12/27/2007
• Issued: 07/17/2012
• Est. Priority Date: 09/24/2002
• Status: Active Grant

• Current Assignee: Duke University
• Original Assignee: Duke University
• Inventors: Pollack, Michael G., Pamula, Vamsee K., Fair, Richard B.
• Primary Examiner(s): Olsen, Kaj K
• Application Number:
  US11/965,152
• Publication Number:
  US 20080247920A1
• Time in Patent Office: 1,664 Days
• Field of Search: 204/450, 204/600
• US Class Current: 204/600
• 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

An apparatus for manipulating droplets is provided. In one embodiment, the apparatus includes a substrate having electrodes and adjacent reference elements configured for manipulating a droplet on a surface of the substrate. Other embodiments having a top plate, a footprint, and a dielectric are also included.

Claims

1. An apparatus for manipulating droplets, the apparatus comprising a substrate comprising drive electrodes and adjacent reference elements configured for manipulating a droplet on a surface of the substrate, wherein

the reference elements comprise a two dimensional grid of conducting lines electrically and physically distinct from the drive electrodes;

the apparatus further comprises a plate spaced from the surface of the substrate by a distance to define a space between the plate and the surface of the substrate, wherein the distance is sufficient to contain a droplet disposed in the space; and

the plate comprises a hydrophobic plate surface facing the surface of the substrate.

2. The apparatus of claim 1 wherein one or more of the drive electrodes is:

(a) coupled to a source of potential;

or

(b) floated.

3. The apparatus of claim 1 wherein the two dimensional grid of conducting lines is:

(a) coupled to a source of potential;

or

(b) floated.

4. The apparatus of claim 1 wherein:

(a) one or more of the drive electrodes is;

(i) coupled to a source of potential;

or

(ii) floated; and

(b) the two dimensional grid of conducting lines is;

(i) coupled to a source of potential which differs from the potential of (a);

or

(ii) floated.

5. The apparatus of claim 1 comprising an array of the drive electrodes.

6. The apparatus of claim 1 wherein the drive electrodes and reference elements are in a substantially coplanar relationship.

7. The apparatus of claim 1 comprising drive electrodes covered by a dielectric layer.

8. The apparatus of claim 7 wherein at least a portion of the dielectric layer is hydrophobic.

9. The apparatus of claim 1 wherein at least outer portions of the drive electrodes and the reference elements are respectively hydrophobized.

10. The apparatus of claim 1 further comprising a hydrophobic film disposed on the drive electrodes and the reference elements.

11. The apparatus of claim 1 comprising a filler fluid disposed in the space.

12. The apparatus of claim 1 further comprising an electrode selector for sequentially activating and de-activating one or more selected drive electrodes of the array.

13. The apparatus of claim 12 wherein drive electrodes are arranged such that the sequentially activating and de-activating one or more selected drive electrodes of the array sequentially biases the selected drive electrodes to an actuation voltage such that a droplet disposed on the surface of the substrate moves along a path defined by the selected drive electrodes.

14. The apparatus of claim 12 wherein the two dimensional grid of conducting lines is set to a reference voltage less than the actuation voltage.

15. The apparatus of claim 12 wherein the two dimensional grid of conducting lines is set to ground potential.

16. The apparatus of claim 12 wherein the two dimensional grid of conducting lines is floated.

17. The apparatus of claim 12 wherein the electrode selector comprises an electronic processor.

18. The apparatus of claim 1 comprising a droplet inlet communicating with the surface.

19. The apparatus of claim 1 comprising a droplet outlet communicating with the surface.