A covalently imprinted photonic crystal for glucose sensing

We demonstrate a glucose-sensing material based on the combination of photonic crystal templating and a molecular-imprinting technique. In the presence of the target molecule glucose, poly(N-isopropylacrylamide-co-2- hydroxyethyl methacrylate) hydrogel with pendent phenylboronic acid groups was synthesized in the void of a poly(methyl methacrylate) (PMMA) colloidal crystal. After removing the PMMA photonic crystal template and glucose molecules, a 3D-ordered porous covalently imprinted photonic crystal (CIPC) hydrogel was created. The unique 3D-ordered porous hydrogel revealed optical changes in response to glucose concentration. At pH = 11 and 37°C, the diffraction of CIPC redshifted from 725 nm to 880 nm in response to 20 mmol L^-1 glucose. Due to the covalently imprinted recognizer, boronic acid group, the selectivity of the CIPC towards glucose over D-ribose and L-rhamnose was improved significantly.