GLUCOSE BIOSENSOR BASED ON OXYGEN-ELECTRODE .3. LONG-TERM PERFORMANCEOF THE GLUCOSE BIOSENSOR IN BLOOD-PLASMA AT BODY-TEMPERATURE

A potentially implantable glucose biosensor for continuous monitoring of glucose levels in diabetic patients has been developed. The glucose biosensor is based on an amperometric oxygen electrode and Glucose Ox idase immobilized on carbon powder held in a form of a liquid suspensi on. The enzyme material can be replaced (the sensor recharged) without sensor disassembly. Glucose diffusion membranes from polycarbonate (P C) and from polytetrafluorethylene (PTFE) coated with silastic are use d. Sensors were evaluated continuously operating in phosphate buffer s olution and in undiluted blood plasma at body temperature. Calibration curves of the sensors were periodically obtained. The sensors show st able performance during at least 1200 hours of operation without refil ling of the enzyme. The PTFE membrane demonstrates high mechanical sta bility and is little effected by long-term operation in undiluted bloo d plasma.