Multifunctional responsive gel membranes present a new and promising platform for the development of "smart" devices for bioseparation, biosensors, and "smart" drug release. These membranes combine functions of stimuli-responsive control and regulation of the mass transport with a range of properties such as storage, catalysis of chemical reactions, antimicrobial activity, and optical-signal transduction. The membranes, whether surface attached or free standing, can be prepared from synthetic polymers or biopolymers. The membranes regulate mass transport in a broad range, and demonstrate a rapid response to external signals.