Electrodeposition of thin chitosan membrane in freestanding SU-8 microfluidic channel for molecular addressing by capillary effect

The electrodeposition of thin chitosan membrane in freestanding microfluidic channel with capillary effect for biomolecule assembly of biosensor is investigated. A dry SU-8 sheet is used to fabricate freestanding fluidic microchannel by microelectromechanical systems (MEMS) technology. The hydrophobic surface of SU-8 microchannel transformed to hydrophilic surface by plasma treatment. The thin chitosan membrane is deposited on hydrophilic SU-8 microchannel by capillary effect, and miniaturization of sensor device is obtained. Membrane thickness of chitosan in freestanding channel can be controlled by concentration of chitosan solution and deposition time. The results show that thin chitosan membrane can be deposited by capillary effect in freestanding channel, and the deposited chitosan thin film shows great potential for immobilizing enzyme on the surface for compact biosensor device.