EXPERIMENTS AIMED AT ENABLING THE DEVELOP MENT OF AN IMPLANTABLE GLUCOSE SENSOR-BASED ON POLARIMETRY

In vitro and in vivo experiments devised with the aim of developing a permanently implantable glucose sensor based on polarimetry are descri bed. It was found that in ultrafiltrated human blood plasma the overal l optical rotation was 94% specific for glucose, and that polarisation photometry yielded a sufficiently sensitive signal for in vivo glucos e detection. The three types of capillary membrane intended for implan tation that we tested, revealed an in vitro response time to glucose c oncentration of 10 minutes; when implanted, they maintain this over a period of weeks, during which time the same glucose concentrations can be measured daily in ultrafiltrated capillary fluid as in the blood o f the animals (guinea pigs). The drop in glucose concentration induced 20 minutes after a single administration of insulin can also be detec ted in both fluids. The experiments described indicate that the develo pment of an implantable polarimetric glucose sensor is possible.