The GOD-H2O2-electrode as an approach to implantable glucose sensors

The long-term function of glucose sensors under in-vivo conditions is the first prerequisite in the development of glucose-controlled insulin infusion systems. Amperometric enzyme glucose sensors measuring H2O2 from the enzymatic glucose oxidation are defeated to certain poisoning effects of the electrochemical system and to alterations of the diffusional properties, both resulting in unpredictable changes of the sensor signal. To interpret the signal of subcutaneously implanted sensors after reaching a certain balance of the altering processes, the wick-technique has been established as an independent reference method applicable in the interstitial fluid. Based on the comparison of the wick-glucose concentration and the circulating plasma glucose concentration the in vivo-calibration of the sensor current according to plasma glucose concentration is proven.