A Flexible Glucose Sensor with Anti-Swelling and Conductivity Zwitterionic Hydrogel Enzyme Membrane

This paper reports a flexible electrochemical glucose sensor with a zwitterionic hydrogel enzyme membrane cross-linked by AlCl3. Multivalent metal ions Al³⁺ are used to cross-link the zwitterionic carboxylic acid beet (pCBMA) to improve the anti-swelling and the load of glucose oxidase enzyme (GOx) of the hydrogel enzyme membrane by increasing the cross-linking density of hydrogels. The anions Cl^- corresponding to Al³⁺ can improve the conductivity as their free status in hydrogel. The high conductivity and load of GOx of the Al³⁺ crosslinked zwitterionic hydrogel enzyme membrane improve the sensitivity of the sensor, which is about 60 times higher than that of the sensor with the pure zwitterionic hydrogel enzyme membrane. In addition, the anti-swelling property of the hydrogel has little damage to the electrodes of the flexible sensors over time which may occur in general flexible electrode-based sensors.