Methods for Manipulating Droplets by Electrowetting-Based Techniques

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, 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 a first voltage to position the starting droplet across the three drive electrodes;
• and
• (c) biasing the medial drive electrode to a second voltage different from the first voltage to split the starting droplet into first and second split droplets, whereby the first split droplet is formed on the first outer drive electrode and the second split droplet is formed on the second outer drive electrode;
• and
• wherein the substrate further comprises a grounded electrode, and the droplet overlaps the grounded electrode.

A method for merging two or more droplets into one droplet, comprising the steps of:

• (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 is adjacent to the medial electrode, and the second droplet is disposed on the second outer electrode and is adjacent to the medial electrode;
• (b) selecting one of the three electrodes as a destination electrode;
• (c) selecting two or more of the three electrodes for biasing based on the selection of the destination electrode;
• and
• (d) biasing the electrodes selected 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.