Filler Fluids for Droplet Operations

A droplet microactuator comprising:

• (a) a first substrate comprising electrodes configured to effect electrowetting mediated droplet operations on a surface of the first substrate;
• (b) a second substrate spaced from the surface of the first substrate by a distance sufficient to define an interior volume between the first substrate and the second substrate;
• and
• (c) a droplet and a filler fluid in the interior volume, wherein the droplet is surrounded by the filler fluid, and arranged with respect to the electrodes in a manner which permits electrowetting mediated droplet operations to be effected on the droplet using the electrodes, wherein the filler fluid comprises an oil and a surfactant, and wherein the surfactant comprises nonionic low hydrophile-lipophile balanced (HLB) surfactant with an HLB less than about 10.

A droplet microactuator comprising:

• (a) a first substrate comprising electrodes configured to effect electrowetting mediated droplet operations on a surface of the first substrate;
• (b) a second substrate spaced from the surface of the first substrate by a distance sufficient to define an interior volume between the first substrate and the second substrate;
• and
• (c) a droplet and a filler fluid in the interior volume, wherein the droplet is surrounded by the filler fluid, and arranged with respect to the electrodes in a manner which permits electrowetting mediated droplet operations to be effected on the droplet using the electrodes, wherein the filler fluid comprises an oil and a surfactant, and wherein the surfactant is a nonionic low hydrophile-lipophile balanced (HLB) surfactant or a nonionic lipophile surfactant.

A droplet microactuator comprising:

• (a) a first substrate comprising electrodes configured to effect electrowetting mediated droplet operations on a surface of the first substrate;
• (b) a second substrate spaced from the surface of the first substrate by a distance sufficient to define an interior volume between the first substrate and the second substrate;
• and
• (c) a droplet and a filler fluid in the interior volume, wherein the droplet comprises whole blood and is surrounded by the filler fluid, and arranged with respect to the electrodes in a manner which permits electrowetting mediated droplet operations to be effected on the droplet using the electrodes, wherein the filler fluid comprises an oil and a surfactant, and wherein the surfactant comprises nonionic low hydrophile-lipophile balanced (HLB) surfactant with an HLB less than about 2.

A droplet microactuator comprising:

• (a) a first substrate comprising electrodes configured to effect electrowetting mediated droplet operations on a surface of the first substrate;
• (b) a second substrate spaced from the surface of the first substrate by a distance sufficient to define an interior volume between the first substrate and the second substrate;
• and
• (c) a droplet and a filler fluid in the interior volume, wherein the droplet comprises whole blood and is surrounded by the filler fluid, and arranged with respect to the electrodes in a manner which permits electrowetting mediated droplet operations to be effected on the droplet using the electrodes, wherein the filler fluid comprises an oil and a surfactant, and wherein the oil comprises a silicone oil and the surfactant comprises a nonionic lipophile surfactant.