Sensors for glucose monitoring: technical and clinical aspects

The aim of this article is to critically discuss the technical and clinical aspects of glucose sensors and to briefly review current technical develop ments. This includes sensors for spot glucose measurements as well as those used for continuous glucose monitoring. Continuous glucose monitoring in p articular should supply the diabetic patient with all the information requi red to optimize insulin therapy and metabolic control. Such systems should also allow hypo- and hyperglycemic episodes to be avoided. During the last 30 years numerous attempts have been made to develop glucos e sensors, and new major breakthroughs have been announced repeatedly. Howe ver, up until now no glucose sensor has been available that can be used by diabetic patients in daily life conditions. Also one type of glucose sensor , a glucose electrode, recently received approval by the Food and Drug Admi nistration (USA) and is commercially available. Other glucose sensors emplo ying the transdermal, microdialysis or open tissue microperfu sion techniqu e are currently under clinical development and may also become available in the near future. The types of glucose sensors referred to so far are not t ruly non-invasive, but only minimally invasive. They measure glucose concen tration in the interstitial fluid of the skin or the subcutis. Non-invasive optical glucose sensors are designed to monitor glucose changes in the ski n by directing light through it. They measure the characteristics of the re flected light that are changed as the result of an interaction with glucose . However, none of the attempts with optical glucose sensors have resulted thus far in the development of a sensor that allows monitoring of glucose w ith sufficient accuracy and precision within the clinically relevant glucos e range in daily life conditions. Nevertheless, more minimal-invasive gluco se sensors systems will become available for practical use in the near futu re, whereas it is still uncertain if this can be said for any non-invasive glucose sensor. Copyright (C) 2001 John Wiley & Sons, Ltd.