Characterization and design of digitizing processes for uniform and controllable droplet volume in ewod digital microfluidics

Abstract

We report characterization and precise control of droplet volume for digital microfluidics under electrowetting-on-dielectric (EWOD) actuation both in air and oil environments. By using multi-layer printed circuit board (PCB) as an EWOD chip and custom-making an automatic control board, the restrictions on the electrode pattern design and driving signal are eliminated, empowering us to run various electrode sequences and electric signals. Reading droplet volumes optically or electrically, we characterize and optimize the droplet creation and cutting processes. The results lead to more uniform and repeatable droplet volume, which is essential for a precision instrumentation application. The tunable droplet volume is also available by changing the digitizing parameters.