Three-dimensional digital microfluidics using an alternative current electrowetting-on-dielectric (AC-EWOD)

This paper describes three-dimensional (3D) digital microfluidics based on an alternative current electrowetting-on-dielectric (AC-EWOD) principle. To achieve the 3D manipulation of a droplet in two parallel plates, the dynamic behaviors of a water droplet actuated by AC-EWOD in various conditions are investigated by using high speed images. From the investigation, the optimum experimental conditions such as the applied frequency, switching time, and gap between the top and bottom plates are obtained. As the concept proof, the 3D manipulation of a droplet is finally achieved by the combination of horizontal and vertical AC-EWOD actuation, providing us more space for digital microfluidics.