ELECTROCATALYTIC GLUCOSE SENSOR FOR LONG-TERM IN-VIVO USE

A catheter shaped electrocatalytic glucose sensor for in vivo applicat ion has been developed to determine the glucose level in blood and con trol the insulin dosage in a closed loop system for diabetes therapy. The principle of measurement is based on the electrochemical oxidation of glucose at a membrane-covered platinum electrode. For various pote ntial steps, the impedance obtained at two different frequencies is a function of the glucose concentration. A series of implantations in th e vena cava of sheep demonstrated the potential feasibility of the sen sor. It was possible to determine the glucose concentration in sheep f or more than 130 days with tolerable deviations from glucose reference measurements. The mean error was 2.5 mmol/l. The catheter was explant ed after 211 days and histological examination revealed a good biocomp atibility of all materials used.