Developing glucose sensors for in vivo use.

The potential uses for in vivo glucose sensors in patients with diabetes mellitus include an alarm for low blood-glucose concentrations, a continuous read-out of glucose levels and as part of a feedback-controlled insulin delivery system (artificial pancreas). Most experience has been with implanted amperometric enzyme electrodes, though sensors based on field-effect transistors (FETs) show promise for the future. Sensing responses at the subcutaneous site correlate with plasma-glucose values, but there are often problems of calibration and drift. Implantable glucose sensors are not therefore in routine clinical use. Non-invasive glucose sensing based on near-infrared spectroscopy is being actively investigated as an alternative strategy.