title: Top-down and bottom-up fabrication techniques for hydrogel based sensing and hormone delivery microdevices.
abstract: We review a set of studies dealing with molecular (glucose) sensing and hormone delivery, in which the swelling and shrinking of a hydrogel as a function of glucose concentration play a central role. Confining hydrogels in microfabricated structures permits transduction of their chemomechanical behaviors. Prototype microdevices for wireless glucose sensing and closed loop insulin delivery control have been designed using hydrogels containing phenylboronic acid sidechains. While these devices exhibit desired responses, improved response time is needed, warranting further miniaturization. In a separate application, geometric confinement of glucose oxidase by a pH-sensitive hydrogel membrane sets up a nonlinear feedback loop which enables rhythmic swell/shrink cycles when the system is exposed to a constant glucose concentration. The latter system may be applied to delivery of gonadotropin release hormone, for which rhythmicity of secretion is essential for therapeutic function.
authors: Department of Pharmaceutics, University of Minnesota, Minneapolis, MN 55455, USA. siegel017@umn.edu
authors: Ronald A
authors: RA
authors: Siegel
authors: Eric E
authors: EE
authors: Nuxoll
authors: Marc A
authors: MA
authors: Hillmyer
authors: Babak
authors: B
authors: Ziaie
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation*; D004337:Drug Carriers / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D007332:Insulin Infusion Systems; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D008904:Miniaturization; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013686:Telemetry / Q000295:instrumentation*
chemical_list: D004337:Drug Carriers; D020100:Hydrogels