Implanted electrochemical glucose sensors for the management of diabetes

By maintaining a near normal (70-120 mg/dL) glucose concentration, diabetic patients can drastically reduce the likelihood of the occurrence of diabet es complications. In the near future, subcutaneously implanted electrochemi cal glucose sensors will be available to provide frequent or continuous inf ormation on which timely treatment decisions, such as insulin injection or glucose source intake, can be based, as well as timely alarm signals. The c urrently engineered devices are of three types: (a) innocuous microsensors, with actively mass-transporting areas <10(-3) cm(2), replaced twice a week by the patient; (b) self-contained, surgeon-implanted, transmitter-contain ing packages of >1 cm(2) area, operating for >100 days; and (c) devices tra nsporting subcutaneous fluid to an external sensor, based on implanted micr ofiltration or microdialysis fibers or on iontophoretic transport of the su bcutaneous fluid through the skin.