Co-planar light-actuated optoelectrowetting microfluidic device for droplet manipulation

We report on a co-planar light-actuated digital microfluidics device that features a metal mesh grid integrated on the device surface to allow droplets to be exposed from above. We discuss a theoretical circuit model for our co-planar optoelectrowetting (OEW) design that allows for the optimization of droplet actuation while maintaining reliable droplet movement. Basic droplet manipulations such as merging and parallel actuation of droplets are achieved at speeds of up to 4.5 cm / s. The co-planar OEW device design benefits from having an open top design that allows for a wider range of system integration configurations than previous generations of OEW devices. A droplet-on-demand dispensing system from above is integrated with the co-planar OEW device to demonstrate the versatility of this optofluidic platform. The ability to inject, collect, and position individual droplets to form large-scale droplet arrays of up to 20 × 20 is achieved.