A soft and flexible biosensor using a phospholipid polymer for continuous glucose monitoring

A flexible biosensor using a phospholipid polymer to immobilization of glucose oxidase (GOD) was fabricated and tested. At first, an enzyme membrane formed by immobilizing GOD onto a porous polytetrafluoroethylene (PTFE) membrane using the phospholipid polymer (2-methacryloyloxyethyl phosphorylcholine (MPC) copolymerized with 2-ethylhexylmethacrylate (EHMA) : PMEH) was evaluated. According to the result of amperometric measurement, average density of GOD to be immobilized was optimized to 38.9 units cm −2 . Temperature and pH dependences were also investigated. Then, a flexible glucose sensor was fabricated by immobilizing GOD onto a flexible hydrogen peroxide electrode using PMEH. The flexible glucose sensor showed a linear relationship between output currents and glucose concentration in 0.05–1.00 mmol L −1 , with a correlation coefficient of 0.999. The calibration range covered the normal tear glucose level of 0.14–0.23 mmol L −1 . This indicates that the flexible biosensor is considered to be useful for monitoring of glucose in tear fluids.