Study of glucose biosensor lifetime improvement in 37 °C serum based on PANI enzyme immobilization and PLGA biodegradable membrane

●Polyaniline nanofibers for excessive glucose oxidase immobilization.●PLGA polymers were introduced as a degradable out coating of the sensor.●The glucose sensor left 80% of its initial sensitivity after 44 days in 37 °C serum.●We provided a compatible enzyme immobilization approach for implantable sensors.●We described a degradable member base relay-released mechanism.

Glucose sensors with long life span were fabricated and evaluated in 37 °C serum to imitate in vivo conditions. Polyaniline nanofibers were electrodeposited on sensor electrodes for excessive glucose oxidase immobilization to extend the lifetime of sensors. The sensitivity of sensors stored in 37 °C bovine serum was stable for 20 days without apparent descents, and still remained 45% of its initial value after 44 days. In order to further improve the life span of sensors, a degradable polymer film, poly lactic-co-glycolic acid (PLGA), was used as an out coating layer of glucose sensors. Results showed that the PLGA coated glucose sensors left 80% of its initial sensitivity after 44 days' storage in 37 °C bovine serum. The sensors could be potentially used as long-term implantable devices for real time monitoring of glucose levels.