In vivo evaluation of an amperometric glucose sensor implanted subcutaneously in rats

A miniaturized enzymatic glucose sensor was evaluated after implantation in the subcutaneous tissue of normal rats. Operated at 0.7 V for the detection of hydrogen peroxide, the in vitro characteristics of these sensors linear range up to 18 mM glucose, sensitivity of 2.5 ± 0.9 nA/mM and 95 % response time of 180 ± 4 s were unaffected by a reduction of pO₂ down to 5 kPa. Following the sensor in vivo calibration, its response to different glycemia variations patterns was evaluated to begin with during 3 to 6 hours and then also during several days. The mean tissue glucose levels were within 20 % of those measured conventionally in plasma over the concentration range investigated i.e. 2-16 mM.