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 diabetes complications. In the near future, subcutaneously implanted electrochemical glucose sensors will be available to provide frequent or continuous information on which timely treatment decisions, such as insulin injection or glucose source intake, can be based, as well as timely alarm signals. The currently engineered devices are of three types: (a) innocuous microsensors, with actively mass-transporting areas <10⁻³ cm², replaced twice a week by the patient; (b) self-contained, surgeon-implanted, transmitter-containing packages of >1 cm² area, operating for >100 days; and (c) devices transporting subcutaneous fluid to an external sensor, based on implanted microfiltration or microdialysis fibers or on iontophoretic transport of the subcutaneous fluid through the skin.