(618h) Glucose Sensitivity of Hydrogels Containing Phenylboronic Acid and a Prototype of Biosensor for the Diabete

Hydrogels are three dimensional polymeric networks which swell in aqueous solution without dissolution. With manipulation of chemical structure hydrogels can be designed to undergo volume changes in response to environmental stimuli such as temperature, pH, and electric field. In particular, glucose-sensitive hydrogels that swell or shrink according to blood glucose concentration are very useful for developing a glucose sensor. We synthesized glucose-sensitive hydrogels by using methacrylamidophenylboronic acid (MPBA), acrylamide (AAm), with/without N,N’-dimethylaminopropyl methacrylamide (DMP). MPBA-co-AAm hydrogels bind sugar molecules such as fructose and glucose, and change their volume with change in sugar concentrations at higher pH values than pKa of MPBA, pH 8.8. DMP lowers pKa by interaction with MPBA moieties, allowing binds of sugar molecules to MPBA at physiological pH value. Swelling behaviors were studied by measuring changes in diameter of capillary-shaped hydrogels at different pH values and at different sugar concentrations. In addition, we conducted compression test to see relaxation modulus related crosslink density. This experiment confirmed that only glucose molecules could make reversible crosslinks with MPBA moieties. Furthermore, we developed a prototype of a glucose sensor based on a micro-sized MPBA-co-AAm hydrogel. PRINT (Particle Replication In Non-wetting Templates) technique was used for mass production of the micro-sized hydrogels that allow quick responses in diffusion based system. The prototype of a glucose sensor consisted of nanoporous aluminum oxide membrane, a piece of the hydrogel, and a pressure sensor. Swelling pressure changes with changes of sugar concentration were monitored by a voltage meter over time. This glucose-sensitive hydrogel based prototype would be applied to development of an implantable glucose sensor along with insulin delivery system.