A Highly Sensitive Glucose Sensor with Anti-Swelling Zwitterionic Hydrogel Enzyme Membrane

This paper reports a flexible electrochemical glucose sensor modified by an anti-swelling zwitterionic hydrogel enzyme membrane. The enzyme membrane is formed by thermal polymerization of the zwitterionic monomer sulfonate betaine, increasing the cross-linking density to reduce the pore size by the hydrogen bonding between carboxylated cellulose nanofibers and the hydrogel network. The reduction of pore size further improves enzyme load. At the same time, AlCl
3
was doped into the hydrogel enzyme membrane to improve the conductivity. High enzyme load and conductivity of zwitterionic hydrogel enzyme membranes increase the sensitivity of the sensors to glucose by about 14-fold. In addition, the anti-swelling property of the hydrogel has little damage to the electrodes of the sensors over time, which may occur in general hydrogel-modified sensors.