Glucose-sensitive membrane with phenylboronic acid-based contraction-type microgels as chemical valves

Phenylboronic acid (PBA) is an important glucose report, and glucose-sensitive membranes have great potential in self-regulated insulin release. Herein, a novel kind of glucose-sensitive membrane with PBA-based contraction-type poly(N-isopropylacrylamide-co-2-acrylamido-phenylboronic acid) (P(NIPAM-2-AAPBA)) microgels as chemical valves was fabricated. Unlike other PBA-based materials, P(NIPAM-2-AAPBA) microgels respond to glucose via a different mechanism and contract in the presence of glucose instead of expanding. The membranes were prepared by phase separation of blends of poly(vinylidene fluoride) (PVDF)/P(NIPAM-2-AAPBA) microgels/NMP in water. Compared with the pure PVDF membrane, the blend membranes show a higher water flux and better antifouling properties because of increased pore size, porosity and improved hydrophilicity. The membranes show temperature- and glucose-sensitive permeability, which was attributed to the “opening” and “closing” of the channels caused by conformational changes of P(NIPAM-2-AAPBA) microgels. With increasing microgel content, the glucose sensitivity of the blend membranes increases. More importantly, for membranes with a high microgel content, the addition of glucose accelerates the diffusion of insulin across the membranes, suggesting their potential application in self-regulated insulin delivery. Schematic diagram of glucose-sensitive membrane with phenylboronic acid-based contraction-type microgels as chemical valves. - A novel kind of glucose-sensitive membrane was constructed by non-solvent induced phase separation method. - Phenylboronic acid-based contraction-type glucose-sensitive microgels acted as chemical valves of the membrane. - The blend membranes have glucose-sensitive insulin permeability at physiological temperature and pH.