A Parylene MEMS Electrothermal Valve

Abstract—The first microelectromechanical-system normally closed electrothermal valve constructed using Parylene C is de-scribed, which enables both low power (in milliwatts) and rapid operation (in milliseconds). This low-power valve is well suited for applications in wirelessly controlled implantable drug-delivery systems. The simple design was analyzed using both theory and modeling and then characterized in benchtop experiments. Oper-ation in air (constant current) and water (current ramping) was demonstrated. Valve-opening powers of 22 mW in air and 33 mW in water were obtained. Following integration of the valve with catheters, our valve was applied in a wirelessly operated microbo-lus infusion pump, and the in vivo functionality for the appropri-ateness of use of this pump for future brain mapping applications in small animals was demonstrated. [2008-0322] Index Terms—Drug delivery, electrothermal valve, Parylene C, wireless operation