INTEGRATED IMPLANTABLE DEVICE FOR LONG-TERM GLUCOSE MONITORING

In this study we report the development of an integrated implantable d evice for glucose monitoring. The dimensions of the device (5.0 x 7.0 x 1.5 cm) allow implantation under the abdominal skin of a large anima l for in vivo evaluation of sensor performance. The experimental set-u p includes amperometric glucose biosensor, a miniature potentiostat, a n FM signal transmitter, a power supply and an antenna and receiver li nked to a computer-based data acquisition system. The device performan ce was evaluated in vitro using a ten-day continuous test and other lo ng-term operation experiments. The biosensor was tested in different m odel solutions that simulated the physiological environment in which i t will be ultimately used. A linear response to glucose concentration was obtained up to 25 mM glucose, with a sensitivity of less than 0.5 mu A/mM. The ability of the biosensor to measure glucose levels in ser um was also tested, and a good correlation demonstrated between glucos e serum levels measured by routine technique and those measured using the biosensor (R(2) = 0.993; slope = 0.996). Initial results obtained from the short-term subcutaneous implantation of the sensor demonstrat e its potential for the monitoring of glucose concentration in vivo.