Defining the period of recovery of the glucose concentration after its local perturbation by the implantation of a miniature sensor

At the wound caused by implanting a subcutaneous glucose sensor, the concentration of glucose differs transiently from that in the subcutaneous fluid near nonwounded skin. The period of recovery differs for different wounds and is difficult to predict. A diabetic patient implanting a subcutaneous sensor needs to know whether the transient difference subsided sufficiently for the sensor readings and the sensors in vivo calibration to be valid. The miniature amperometric glucose sensor has a compound membrane including layer of glucose oxidase the reaction centers of which are electrically connected to the electrode through a redox polymer; layers excluding interferents and poisons of the electrocatalytic oxidation of glucose; and a layer reducing fouling by components of the biological fluids. We show that the sensor maintains its in vitro sensitivity after its implantation for four hours in the jugular vein and in the peritoneal fluid of the rat. For diabetic patient who implants the sensor the fourhour period is long enough for the insertiontraumacaused local perturbation of the glucose concentration to subside and to safely rely on the readings of the implanted sensor.