Apparatus for Manipulating Droplets

• US 20080247920A1
• Filed: 12/27/2007
• Published: 10/09/2008
• Est. Priority Date: 09/24/2002
• Status: Active Grant

• Current Assignee: Duke University
• Original Assignee: Duke University
• Inventors: Pamula, Vamsee K., Pollack, Michael G., Fair, Richard B.
• Granted Patent: US 8,221,605 B2
• Time in Patent Office: Days
• US Class Current: 422/243
• 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 electrodes and adjacent reference elements configured for manipulating a droplet on a surface of the substrate.

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

(a) coupled to a source of potential;

or

(b) floated.

3. The apparatus of claim 1 wherein one or more of the reference elements is:

(a) coupled to a source of potential;

or

(b) floated.

4. The apparatus of claim 1 wherein:

(a) one or more of the electrodes is;

(i) coupled to a source of potential;

or

(ii) floated; and

(b) one or more of the reference elements 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 electrodes.

6. The apparatus of claim 1 comprising an array of the reference elements.

7. The apparatus of claim 6 wherein the array of reference elements is electrically distinct from the electrodes.

8. The apparatus of claim 6 wherein the array of reference elements is physically distinct from the electrodes.

9. The apparatus of claim 1 wherein the reference elements comprise conducting lines.

10. The apparatus of claim 1 wherein the reference elements comprise a two dimensional grid of conducting lines.

11. The apparatus of claim 1 wherein the reference elements comprises a grid of elongate structures.

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

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

14. The apparatus of claim 13 wherein at least a portion of the dielectric layer is hydrophobic.

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

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

17. The apparatus of claim 1 further comprising 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.

18. The apparatus of claim 17 wherein the plate comprises a hydrophobic plate surface facing the surface of the substrate.

19. The apparatus of claim 17 comprising a filler fluid disposed in the space.

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

21. The apparatus of claim 20 wherein the sequentially activating and de-activating one or more selected electrodes of the array sequentially biases the selected electrodes to an actuation voltage such that a droplet disposed on the surface of the substrate moves along a path defined by the selected electrodes.

22. The apparatus of claim 20 wherein one or more of the reference elements is set to a reference voltage less than the actuation voltage.

23. The apparatus of claim 20 wherein one or more of the reference elements is set to ground potential.

24. The apparatus of claim 20 wherein one or more of the reference elements is floated.

25. The apparatus of claim 20 wherein the electrode selector comprises an electronic processor.

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

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

28. An apparatus for manipulating droplets, the apparatus comprising:

(a) a substrate comprising electrodes and adjacent reference elements configured for manipulating a droplet on a surface of the substrate; and

(b) 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.

29. An apparatus for manipulating droplets, the apparatus comprising:

(a) a substrate comprising electrodes and adjacent reference elements configured for manipulating a droplet on a surface of the substrate; and

(b) a droplet disposed on an electrode wherein the droplet has a footprint, and the droplet footprint and the electrode have areas which are substantially similar.

30. An apparatus for manipulating droplets, the apparatus comprising:

(a) a substrate comprising electrodes covered by a dielectric layer; and

(b) adjacent reference elements;

wherein the apparatus is configured for manipulating a droplet on a surface of the substrate.

31. An apparatus for manipulating droplets, the apparatus comprising a substrate comprising electrodes covered by a dielectric layer and adjacent reference elements, wherein:

(a) the apparatus is configured for manipulating a droplet on a surface of the substrate, and

(b) one or more of the reference elements is;

(i) coupled to a source of potential; and

/or

(ii) floated.