Ex vivo performance of printed thick film glucose sensors without immobilized glucose oxidase

The present study investigated the temporal modulation in performance of printed thick film electrochemical sensors without immobilized glucose oxidase by comparing the ex vivo performance of such devices with that of in vitro phosphate buffer saline (PBS) maintained sensors, at similar time points. In addition, a preliminary study was conducted to investigate the dependency of the sensor functionality on the method of sterilization. The oxidation and reduction current involving a ferrous-ferric coupling reaction was used to assess the performance of the electrode elements under in vitro and ex vivo conditions. Imaging analysis was employed to investigate the cellular morphology on the surface of the explanted devices. It was concluded that while the devices were affected by the presence of the surrounding biological environment (cellular adhesion, fibrous capsule formation), the ex vivo performance of the printed thick film sensors was comparable to that of the in vitro prototypes, at similar time points.