US 2003/0224528 A1 · Systems and methods for optical actuation of microfluidics based on opto-electrowetting

Abstract

The invention is related to methods and apparatus that manipulate droplets in a microfluidic environment. Advantageously, embodiments of the invention manipulate droplets by controlling the electro-wetting characteristics of a surface with light, thereby inducing a gradient in the surface tension of a droplet. The gradient in the surface tension propels the droplet by capillary force. A variety of operations, such as transporting, joining, cutting, and creating can be performed. Advantageously, embodiments of the invention obviate the need to create a relatively large and complex control electrode array. A plurality of photoconductive cells or a layer of a photoconductive material selectively couples an electrode carrying an electrical bias to otherwise floating conductive cells in response to a beam of light. The electrical bias applied to the conductive cell generates a localized electric field, which can change the contact angle of the droplet, thereby permitting the droplet to be propelled.

Claims28

Dependent claims

A microfluidic circuit adapted to manipulate a droplet in response to light, the microfluidic circuit comprising:

a first wall with at least a conductive layer adapted to be coupled to a first terminal of an alternating current (AC) voltage source;
a second wall adapted to be coupled to a second terminal of the AC voltage source such that an electric field is generated between the first wall and the second wall, where the second wall is responsive to light such that a portion of the second wall that is illuminated by a localized spot of light has a higher electric field intensity than a portion of the second wall that is not illuminated by the localized spot of light, wherein at least one of the first wall and the second wall is further adapted to allow light to pass through;
and
a cavity defined between the first wall and the second wall, where the cavity is adapted to hold the droplet.

1 more element

A microfluidic circuit adapted to manipulate a droplet in response to light, the microfluidic circuit comprising:

a first optical electro-wetting structure adapted to be coupled to a first voltage reference, where the first optical electro-wetting structure includes a first insulating layer and at least a first region sensitive to light such that the first region couples the first voltage reference to at least part of the first insulating layer in response to light;
a second optical electro-wetting structure spaced apart from the first optical electro-wetting structure, where the second optical electro-wetting structure is adapted to be coupled to a second voltage reference, where the second optical electro-wetting structure includes a second insulating layer and a second region sensitive to light such that the second region couples the second voltage reference to at least part of the second insulating layer in response to light, and where the second optical electro-wetting structure is sufficiently transparent to allow light that impinges on a first area of one side of the second optical electro-wetting structure to pass through and expose a corresponding second area of the first optical electro-wetting structure;
and
a cavity defined between the first optical electro-wetting structure and the second optical electro-wetting structure, where the cavity is adapted to hold the droplet.

1 more element

Dependencies are inferred from the claim text.

Systems and methods for optical actuation of microfluidics based on opto-electrowetting

Life of this patent

Systems and methods for optical actuation of microfluidics based on opto-electrowetting

Life of this patent

Abstract

Claims28