The integration of biology and electronics is crucial to developing advanced medical diagnostics and biological experimentation devices. To this end, we investigated the generation of hydrogels from the “biocompatible” polymer chitosan. Specifically, we imposed electrical signals at the biology electronics interface within microfabricated fluidic devices to electrodeposit chitosan hydrogels. Chitosan's unique properties enable electrodeposited hydrogels to be reversibly swollen and de-swollen providing a means for microfluidic valving or for controlled release of entrapped components. Furthermore, the method of anodic deposition reported here allows for one-step biofunctionalization of components for multiplexed electrochemical biosensing. Thus, we believe this electrodeposition method will provide a means to generate hydrogels capable of integrating biology with microelectromechanical systems.