Selective holographic glucose sensors [biosensing applications]

A holographic glucose sensor, based on the swelling state of acrylamide co-polymers containing phenylboronic acid groups, has been developed. Boronic acids are known to bind a variety of cis-diols, including glucose and lactate, which are found in physiological fluids. Incorporation of a tertiary amine along with the phenylboronic acid in the copolymer allowed the boronic acid to achieve the reactive tetrahedral state at physiological pH through intermolecular electron donation from the amine. This facilitated the binding of glucose at physiological pH and increased the selectivity for compounds with multiple cis-diol groups. Glucose caused the polymer to contract as it acts as a cross-linker whereas the binding of lactate caused a slight expansion. The sensor is fully reversible and could be used to monitor continuous changes in glucose concentration in physiological fluids.