Holographic sensors in contact lenses for minimally-invasive glucose measurements

A contact lens with an incorporated glucose-sensitive hologram has been designed as a system for non-invasive measurement of glucose levels in diabetic patients. The hologram consists of an acrylamide copolymer hydrogel with phenylboronic acid groups acting as reversible glucose-binding ligands, allowing dynamic changes in glucose to be detected. The colour of white light reflected off the hologram changes as glucose binds to the phenylboronic acid groups, and this change is used to quantify glucose concentrations. Holograms containing the ligand 3-acrylamidophenylboronic acid (3-APB) were incorporated into a contact lens. The lens was chemically extracted to render it non-toxic. After sterilization through autoclaving, the system still maintained its ability to bind glucose reversibly.