A monolithic polymeric microdevice for pH-responsive drug delivery.

A drug-delivery microdevice integrating pH-responsive nano-hydrogel particles functioning as intelligent nano valves is described. The polymeric microdevices are monolithic without requiring peripheral control hardware or additional components for controlling drug-release rates. pH-responsive nanoparticles were synthesized and embedded into a composite membrane. The resulting pH-responsive composite membranes were integrated with PDMS micro reservoirs via a room-temperature transfer bonding technique to form the proof-of-concept microdevices. In vitro release characterization of the microdevices was conducted in which the release rate of Vitamin B(12) (VB(12)) as a model drug increased dramatically when the local pH value was decreased from 7.4 to 4. This device concept can serve as a platform technology for intelligent drug delivery in response to various in vivo environmental signals.