ELECTROCATALYTIC GLUCOSE SENSOR

An electrocatalytic glucose sensor for in vivo application has been de veloped. The sensor is a flow-through cell with three electrodes and c an be integrated into a blood vessel. The principle of measurement is based on the direct electrochemical oxidation of glucose at a membrane -covered noble-metal electrode. To test the potential long-term in viv o function of the sensor, it was implanted in the carotid artery of a sheep. Thus, the sensor performance was verified over a period of 71 d ays. During this time, a nearly constant blood flow through the cell w as achieved, which indicates good blood compatibility of the materials used. It was possible to set up a calibration that was valid over 24 days (mean error 2.3 mmol l(-1)). The tested cross-sensitivity of the sensor towards cysteine, acetyl salicylic acid and other small molecul es shows tolerable effects on this type of glucose measurement. Only h igh concentrations of lactate and ethanol require a special adaptation of the calibration to suppress their influence. Minor cross-sensitivi ty and promising long-term stability recommend this type of sensor for in vivo monitoring of blood sugar level. However, for intravasal appl ication, it is necessary to modify the present sensor design to a cath eter-type construction.