A highly efficient and reliable electrowetting on dielectric device for point-of-care diagnostics

A highly efficient and reliable electrowetting on dielectric (EWOD) digital microfluidics (DMF) chip is proposed. An 8 μm parylene C layer is used as the dielectric material. Extra vapor-phase silane (VPS) is introduced into the chamber and acts as an aerosol primer to enhance the chemical adhesion to the parylene C surface. The EWOD chip can perform droplet dispensing, merging and splitting smoothly in an air ambient. Dual electrode dispensing mode (DEDM) and single electrode dispensing mode (SEDM) are tested to investigate the dispensing volume accuracy. Small deviations (0.0467 μL for DEDM and 0.0303 μL for SEDM) are observed for the dispensing. Droplets from 1.5 μL to 2.3 μL are tested for the minimum splitting voltage. Larger droplets require larger voltages to be split. The proposed EWOD chip is promising for future point-of-care clinical diagnostics.