2-D digital microfluidic system for droplet handling using printed circuit board technology

In this work, a digital microfluidic system for droplet handling using ElectroWetting-On-Dielectrics (EWOD) technique in closed configuration based on Printed Circuit Board (PCB) technology is presented. The proposed system features a bidimensional 24×24-electrodes array controlled by seven control signals that allow to move a droplet along the entire array. A stack of a dielectric layer (SU-8) and a hydrophobic layer (Teflon AF1600) deposited on the PCB complete the EWOD device. Technological processes have been refined and adapted in order to be compatible with the PCB substrate material while ensuring good adhesion as well satisfactory dielectric characteristics. Experimental results of contact angle measurements as a function of the applied voltage are in good agreement with the Lippmann-Young equation. The system has been tested in “closed” EWOD configuration by dispensing 1 μL of water and by driving the fluid over the array applying voltages in the range 15 V to 30 V to the control electrodes.