Microfabrication of a digital microfluidic platform integrated with an on-chip electrochemical cell

We report on an IC compatible microfabrication process proposed for a novel monolithic lab-on-a-chip (LOC) with an electrochemical cell embedded in an electrowetting on dielectric (EWOD) digital microfluidic device. The optimized process focused on the surface modification of Teflon, selective exposure for the electrochemical module and recovery of surface properties by one-step annealing at low temperature. The optimum modification time and annealing temperature were 20 s and 210 °C, respectively. The experimental results from atomic force microscope and contact angle (CA) measurement revealed the effects of surface roughness and apparent CA on the wettability for different etch times. The multifunctionality of droplet creation, merger and transportation in the EWOD microfluidic module and sensitive electrochemical detection for the redox probe were realized simultaneously. The proposed microfabrication process has many advantages of remarkable simplicity, prominent repeatability, low cost and compatibility with standard IC processes. It shows great promise for the microsystem of the microfluidic unit and detecting cell, and gives a brilliant conception for the future fabrication of monolithic LOC integrated with functional detection.