Methods and apparatus for manipulating droplets by electrowetting-based techniques
First Claim
1. An apparatus for manipulating droplets, comprising:
- (a) a substrate comprising a substrate surface;
(b) an array of electrodes disposed on the substrate surface;
(c) an array of reference elements settable to a reference potential disposed in substantially co-planar relation to the electrode array, each reference element adjacent to at least one of the electrodes;
(d) a dielectric layer disposed on the substrate surface and patterned to cover the electrodes; and
(e) an electrode selector for sequentially activating and de-activating one or more selected electrodes of the array to sequentially bias the selected electrodes to an actuation voltage, whereby a droplet disposed on the substrate surface moves along a desired path defined by the selected electrodes.
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Accused Products
Abstract
An apparatus is provided for manipulating droplets. The apparatus is a single-sided electrode design in which all conductive elements are contained on one surface on which droplets are manipulated. An additional surface can be provided parallel with the first surface for the purpose of containing the droplets to be manipulated. Droplets are manipulated by performing electrowetting-based techniques in which electrodes contained on or embedded in the first surface are sequentially energized and de-energized in a controlled manner. The apparatus enables a number of droplet manipulation processes, including merging and mixing two droplets together, splitting a droplet into two or more droplets, sampling a continuous liquid flow by forming from the flow individually controllable droplets, and iterative binary or digital mixing of droplets to obtain a desired mixing ratio.
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Citations
94 Claims
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1. An apparatus for manipulating droplets, comprising:
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(a) a substrate comprising a substrate surface;
(b) an array of electrodes disposed on the substrate surface;
(c) an array of reference elements settable to a reference potential disposed in substantially co-planar relation to the electrode array, each reference element adjacent to at least one of the electrodes;
(d) a dielectric layer disposed on the substrate surface and patterned to cover the electrodes; and
(e) an electrode selector for sequentially activating and de-activating one or more selected electrodes of the array to sequentially bias the selected electrodes to an actuation voltage, whereby a droplet disposed on the substrate surface moves along a desired path defined by the selected electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for actuating a droplet comprising the steps of:
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(a) providing the droplet on a surface comprising an array of electrodes and a substantially co-planar 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;
(b) activating the first and second electrodes to spread a least a portion of the droplet across the second electrode; and
(c) de-activating the first electrode to move the droplet from the first electrode to the second electrode. - View Dependent Claims (15, 16)
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17. A method for splitting a droplet into two or more droplets, comprising the steps of:
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(a) providing a starting droplet on a surface comprising an array of electrodes and a substantially co-planar array of reference elements, wherein the electrode array comprises at least three electrodes comprising a first outer electrode, a medial electrode adjacent to the first outer electrode, and a second outer electrode adjacent to medial electrode, and the starting droplet is initially disposed on at least one of the three electrodes and at least partially overlaps at least one other of the three electrodes;
(b) activating each of the three electrodes to spread the starting droplet across the three electrodes; and
(c) de-activating the medial electrode to split the starting droplet into first and second split droplets, whereby the first split droplet is disposed on the first outer electrode and the second split droplet is disposed on the second outer electrode. - View Dependent Claims (18, 19, 20)
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21. A method for merging two or more droplets into one droplet, comprising the steps of:
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(a) providing first and second droplets on a surface comprising an array of electrodes and a substantially co-planar array of reference elements, wherein the electrode array comprises at least three electrodes comprising a first outer electrode, a medial electrode adjacent to the first outer electrode, and a second outer electrode adjacent to the medial electrode, the first droplet is disposed on the first outer electrode and at least partially overlaps the medial electrode, and the second droplet is disposed on the second outer electrode and at least partially overlaps the medial electrode;
(b) selecting one of the three electrodes as a destination electrode;
(c) selecting two or more of the three electrodes for sequential activation and de-activation based on the selection of the destination electrode; and
(d) sequentially activating and de-activating the electrodes selected for sequencing to move one of the first and second droplets toward the other droplet or both of the first and second droplets toward each other, whereby the first and second droplets merge together to form a combined droplet on the destination electrode. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. An apparatus for manipulating droplets, comprising:
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(a) a substrate comprising a substrate surface;
(b) an array of electrodes disposed on the substrate surface;
(c) a dielectric layer disposed on the substrate surface and covering the electrodes; and
(d) an electrode selector for dynamically creating a sequence of electrode pairs, each electrode pair comprising a selected first one of the electrodes biased to a first voltage and a selected second one of the electrodes disposed adjacent to the selected first electrode and biased to a second voltage less than the first voltage, whereby a droplet disposed on the substrate surface moves along a desired path running between the electrode pairs created by the electrode selector. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. A method for actuating a droplet comprising the steps of:
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(a) providing the droplet on a surface comprising an array of electrodes, wherein the droplet is initially disposed on a first one of the electrodes and at least partially overlaps a second one of the electrodes separated from the first electrode by a first gap;
(b) biasing the first electrode to a first voltage and the second electrode to a second voltage lower than the first voltage, whereby the droplet becomes centered on the first gap;
(c) biasing a third one of the electrodes proximate to the first and second electrodes to a third voltage higher than the second voltage to spread the droplet onto the third electrode; and
(d) removing the bias on the first electrode to move the droplet away from the first electrode, whereby the droplet becomes centered on a second gap between the second and third electrodes. - View Dependent Claims (51, 52)
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53. A method for splitting a droplet into two or more droplets, comprising the steps of:
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(a) providing a starting droplet on a surface comprising an array of electrodes, wherein the electrode array comprises at least three electrodes comprising a first outer electrode, a medial electrode adjacent to the first outer electrode, and a second outer electrode adjacent to medial electrode, and the starting droplet is initially disposed on at least one of the three electrodes and at least partially overlaps at least one other of the three electrodes;
(b) biasing each of the three electrodes to a first voltage to spread the initial droplet across the three electrodes; and
(c) biasing the medial electrode to a second voltage lower than the first voltage to split the initial droplet into first and second split droplets, whereby the first split droplet is formed on the first outer electrode and the second split droplet is formed on the second outer electrode. - View Dependent Claims (54, 55)
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56. A method for merging two or more droplets into one droplet, comprising the steps of:
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(a) providing first and second droplets on a surface comprising an array of electrodes, wherein the electrode array comprises at least three electrodes comprising a first outer electrode, a medial electrode adjacent to the first outer electrode, and a second outer electrode adjacent to the medial electrode, the first droplet is disposed on the first outer electrode and at least partially overlaps the medial electrode, and the second droplet is disposed on the second outer electrode and at least partially overlaps the medial electrode;
(b) selecting one of the three electrodes as a destination electrode;
(c) selecting two or more of the three electrodes for sequential biasing based on the selection of the destination electrode; and
(d) sequentially biasing the electrodes selected for sequencing between a first voltage and a second voltage to move one of the first and second droplets toward the other droplet or both of the first and second droplets toward each other, whereby the first and second droplets merge together to form a combined droplet on the destination electrode. - View Dependent Claims (57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73)
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74. A method for sampling a continuous liquid flow, comprising the steps of:
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(a) supplying a liquid flow to a surface along a first flow path, the surface comprising an array of electrodes and a substantially co-planar array of reference elements, wherein at least a portion of the liquid flow is disposed on a first one of the electrodes and at least partially overlaps a second one of the electrodes and a reference element between the first and second electrodes;
(b) activating the first electrode, the second electrode, and a third one of the electrodes adjacent to the second electrode to spread the liquid flow portion across the second and third electrodes;
(c) de-activating the second electrode to form a droplet from the liquid flow on the third electrode, whereby the droplet is distinct from and controllable independently of the liquid flow. - View Dependent Claims (75, 76, 77, 78, 79, 80)
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81. A method for sampling a continuous liquid flow, comprising the steps of:
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(a) supplying a liquid flow to a surface along a first flow path, the surface comprising an array of electrodes, wherein at least a portion of the liquid flow is disposed on a first one of the electrodes and at least partially overlaps a second one of the electrodes;
(b) biasing the first electrode, the second electrode, and a third one of the electrodes adjacent to the second electrode to a first voltage to spread the liquid flow portion across the second and third electrodes; and
(c) biasing the second electrode to a second voltage less than the first voltage to form a droplet from the liquid flow on the third electrode, whereby the droplet is distinct from and controllable independently of the liquid flow.
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82. A binary mixing apparatus comprising:
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(a) first mixing unit comprising a first surface area, an array of first electrodes disposed on the first surface area, and an array of first reference elements disposed in substantially co-planar relation to the first electrodes;
(b) a second mixing unit comprising a second surface area, an array of second electrodes disposed on the second surface area, an array of second reference elements disposed in substantially co-planar relation to the second electrodes, and a droplet outlet area communicating with the second surface area and with the first mixing unit; and
(c) an electrode selector for sequentially activating and de-activating one or more selected first electrodes to mix together two droplets supplied to the first surface area, and for sequentially activating and de-activating one or more selected second electrodes to mix together two other droplets supplied to the second surface area. - View Dependent Claims (83)
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84. A binary mixing apparatus comprising:
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(a) first mixing unit comprising a first surface area and an array of first electrodes disposed on the first surface area;
(b) a second mixing unit comprising a second surface area, an array of second electrodes disposed on the second surface area, and a droplet outlet area communicating with the second surface area and with the first mixing unit; and
(c) an electrode selector for dynamically creating a sequence of first electrode pairs on the first surface area and a sequence of second electrode pairs on the second surface area, each first electrode pair comprising a selected first electrode biased to a first voltage and a selected first electrode biased to a second voltage less than the first voltage, each second electrode pair comprising a selected second electrode biased to a third voltage and a selected second electrode biased to a fourth voltage less than the third voltage, whereby two droplets supplied to the first surface area are actuated by the first electrode pairs to mix together and two other droplets supplied to the second surface area are actuated by the second electrode pairs to mix together.
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85. A method for producing a droplet having a desired mixing ratio, comprising the steps of:
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(a) providing a surface, an array of electrodes disposed on the surface, and an array of conducting elements disposed in substantially co-planar relation to the electrode array;
(b) providing a sample droplet having an initial concentration and a diluent droplet on the surface;
(c) merging the sample droplet with the diluent droplet to form a combined droplet by sequentially energizing and de-energizing a selected set of the electrodes; and
(d) mixing the combined droplet to reduce its concentration below the initial concentration of the sample droplet, whereby the reduced concentration of the combined droplet corresponds to an approximate mixing ratio. - View Dependent Claims (86, 87, 88, 89, 90)
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91. A method for producing a droplet having a desired mixing ratio, comprising the steps of:
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(a) providing an array of electrodes disposed on a surface;
(b) providing a sample droplet having an initial concentration and a diluent droplet on the surface;
(c) merging the sample droplet with the diluent droplet to form a combined droplet by dynamically creating a sequence of electrode pairs from the array, each electrode pair comprising a selected first one of the electrodes biased to a first voltage and a selected second one of the electrodes biased to a second voltage less than the first voltage, whereby one of or both the sample droplet and the diluent droplet are actuated along a path defined by the sequence of electrode pairs; and
(d) mixing the combined droplet to reduce its concentration below the initial concentration of the sample droplet, whereby the reduced concentration of the combined droplet corresponds to an approximate mixing ratio. - View Dependent Claims (92)
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93. A method for producing a droplet having a desired final mixing ratio, comprising the steps of:
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(a) in a first mixing unit comprising a first surface area, an array of first electrodes disposed on the first surface area, and an array of first conducting elements disposed in substantially co-planar relation to the first electrodes, mixing a first sample droplet with a first diluent droplet to form a first combined droplet having a desired first intermediate mixing ratio;
(b) in a second mixing unit comprising a second surface area, an array of second electrodes disposed on the second surface area, and an array of second conducting elements disposed in substantially co-planar relation to the second electrodes, mixing a second sample droplet with a second diluent droplet to form a second combined droplet having a desired second intermediate mixing ratio;
(c) transporting the second combined droplet to the first mixing unit; and
(d) in the first mixing unit, combining the first combined droplet with the second combined droplet to form a third combined droplet having the desired final mixing ratio.
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94. A method for producing a droplet having a desired final mixing ratio, comprising the steps of:
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(a) in a first mixing unit comprising an array of first electrodes disposed on a first surface area, mixing a first sample droplet with a first diluent droplet by dynamically creating a first sequence of first pairs of first electrodes, each first pair comprising a first drive electrode biased to a first voltage and a first reference electrode biased to a second voltage less than the first voltage, whereby the first sample droplet and the first diluent droplet are actuated to form a first combined droplet having a desired first intermediate mixing ratio;
(b) in a second mixing unit comprising an array of second electrodes disposed on a second surface area, mixing a second sample droplet with a second diluent droplet by dynamically creating a second sequence of second pairs of second electrodes, each second pair comprising a second drive electrode biased to a third voltage and a second reference electrode biased to a fourth voltage less than the third voltage, whereby the second sample droplet and the second diluent droplet are actuated to form a second combined droplet having a desired second intermediate mixing ratio;
(c) transporting the second combined droplet to the first mixing unit; and
(d) in the first mixing unit, combining the first combined droplet with the second combined droplet to form a third combined droplet having the desired final mixing ratio.
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Specification