A glucose-responsive insulin delivery micro device embedded with nanohydrogel particles as “smart valves”

This paper presents a glucose-responsive micro device capable of modulating drug diffusion rates according to changes in environmental glucose levels. New glucose-responsive composite membranes with enhanced mechanical strength were developed, in which chemically immobilized glucose oxidase and pH-responsive hydrogel nanoparticles were embedded within PDMS micro grids, functioning as intelligent `nano-valves´ in response to surrounding glucose concentration variations. Membrane responsive release profiles were quantified by testing model drug diffusion (bovine insulin), with an increase in release rates in response to increasing glucose levels. The composite membranes were integrated with PDMS drug reservoirs to form proof-of-concept devices. Release profiles of the glucose-responsive micro devices were also measured, demonstrating a marked increase in release rates of insulin when glucose levels in the surrounding media increased from 100 to 300 mg/dL.