Finger-triggered digital microfluidics

We present finger-driven digital microfludics (DMF) to manipulate droplets based on electrowetting on dielectric (EWOD) phenomenon. Instead of using an external power supply, we use a piezoelectric energy harvesting scheme to convert mechanical energy provided by human fingers to electric voltage pulses for droplet actuation. Voltage pulses of amplitudes greater than 40 V can be generated reproducibly by a laminated piezoelectric element. Using this finger-triggered EWOD actuation, we successfully demonstrated basic modes of droplet operation, such as droplet transport, splitting and merging. The results confirm that the electric energy harvested from mechanical energy imparted by human fingers is sufficient to power EWOD-based digital microfluidic devices for droplet manipulation, which are very attractive for various portable applications.