Ricerc@Sapienza

We have developed an EWOD system for lab-on-chip applications, comprising a new technology for EWOD implementation and the related electronic circuit driving. The new technology makes easier the integration of the EWOD technique with sensors and actuators usually present on lab-on-chip systems. It integrates an all-glass microfluidic network with an electrowetting structure, bonding together two glasses processed with microelectronics technologies.

Electrowetting-on-dielectric (EWOD) is a versatile tool in lab-on-chip systems since it controls fluid shape and flow by electrical signals alone without using external pumps and related tube connections. The most versatile EWOD configuration (allowing transport, division and mixing of droplets) is the closed one, where the fluid handling occurs between two coupled glasses.

This paper presents a low temperature technological process able to integrate an all-glass microfluidic network with an ElectroWetting On Dielectric (EWOD) structure for the digital handling of liquids. The fluidic channels result from the wet-etching of the glass, while the electrodes necessary for the droplet movement are deposited on the bottom and top surfaces of the microfluidic structure. The bottom electrodes are produced by a selective and sequential photolithographic pattern of a stack of metals, insulation layer and hydrophobic film.