A glucose-sensitive microgel operating at physiological conditions for glucose detecting and insulin delivery

Abstract

In this paper, a novel microgel that responds at physiological conditions is synthesized by precipitation polymerization of temperature-sensitive monomer N-isopropylmethacrylamide and glucose-sensitive monomer 4-(2-acrylamidoethylcarbamoyl)-3-fluorophenylboronic acid. X-ray photoelectron spectroscopy (XPS) is conducted to verify the successful synthesis. The changes in swelling degree of the microgel induced by temperature, pH, and glucose are demonstrated using dynamic light scattering. As a result, the microgel can function as a glucose concentration detector by measuring the transmittance or grayscale value of its dispersion across various glucose concentrations. Additionally, the drug loading process of the microgel is significantly influenced by the pH and insulin concentrations, as the microgel adsorbs insulin molecules through electrostatic interactions. Under optimum conditions, the microgel exhibits an insulin loading capacity of 144% and an encapsulation efficiency of 89%. Furthermore, an integrated gel is formed by aggregating microgel and insulin using centrifugal force, and it demonstrates pH-induced insulin release behavior.