Classification of Chemical Sensors and Biosensors Based on Fluorescence and Phosphorescence

Abstract

The field of chemical sensors and biosensors based on fluorescence and phos- phorescence is becoming increasingly popular and advances are being reported at a rapid pace. It therefore appears worthwhile to classify these efforts to aid both newcomers and experts of the field in being able to view their work and those of others within a wider context. Among several classification schemes possible, here, one with respect to the mode of action is presented. After historical milestones and definitions of chem- ical sensors and biosensors are being reviewed briefly, the field is subdivided into six major types: Plain fluorometric sensors, direct- and indirect indicator-mediated chem- ical sensors, direct enzymatic biosensors, indicator-mediated enzymatic biosensors, and affinity biosensors. The discussion is accompanied by examples and further subdivisions for some sensor types.