Microfabrication of Bilayer Polymer Actuator Valves for Controlled Drug Delivery

Drug delivery is still a challenging mission in therapeutic treatment. Research on biomedical micro-electromechanical systems (BioMEMS) has led to a diverse range of microsystems for curative applications. This paper introduces miniaturized controlled valves and drug reservoirs for drug delivery systems. Detailed microfabrication processes, optimized package, and optical/electrochemical detection of the proposed device are described. The release mechanism of the device is controlled by a bilayer actuator valve, which consists of a conductive polymer polypyrrole (PPy) film and a thin metal gold (Au) layer. The PPy layer is electrochemically polymerized on the Au layer. Therefore, further miniaturization of the device is possible through microfabrication of the Au layer. A polydimethylsiloxane (PDMS) package is also introduced to prevent the flap from being blocked by the surrounding tissue of the human body. In addition, a parylene coating is applied to minimize the permeability of PDMS. The release process is then verified by an optical and electrochemical detection system.