Light Enabled Digital Microfluidics:A Technology Leading to a Programmable Lab on a Chip

TL;DR

This paper presents a light-enabled digital microfluidic system using optically induced electrowetting with a photoconductive layer, allowing programmable manipulation of droplets and particles on a chip with visible and near-infrared light.

Contribution

It introduces a novel optoelectric electrowetting technique with coplanar electrodes for dynamic droplet and particle manipulation on a single chip.

Findings

Effective droplet manipulation with visible light at 150V and 100-800Hz.

Rapid particle handling using near-infrared light and high-frequency AC signals.

Integration of optical control with microfluidic vortex generation.

Abstract

This fluid dynamics video showcases how optically induced electrowetting can be used to manipulate liquid droplets in open space and particulate phases inside the droplet. A photoconductive layer is added to a conventional electrowetting-on-dielectric (EWOD) structure to generate light enabled virtual electrodes, hence resulting in an eletrowetting action. Coplanar electrodes deployed alternately on a substrate enable open droplet manipulations differentiating from a sandwiched configuration. An integration with an optoelectric method shows dynamic and rapid particle handling by strong micro fluidic vortices in conjunction with other electrokinetic forces inside a droplet. The droplet manipulations are realized with visible illumination and powered at 150 volts peat-to-peak with a low frequency (100 Hz-800 Hz). The particle concentration is achieved on the surface of the same chip but illuminated with a near-infrared (1064 nm) light source and biased with a high frequency (24 kHz) AC signal.