FIBER-OPTIC BIOSENSORS BASED ON FLUORESCENCE ENERGY TRANSFER

Summary-A new optical homogeneous biochemical method for the assay of glucose has been developed, based on fluorescence nergy transfer between a glucose analog, dextran labeled with fluorescein isothiocyanate (FITCdextran), and a glucose-receptor protein, Rhodamine-labeled Concanavalin A (RhConA). When FITCdextran binds to RlConA in solution, and is light-activated, the FITC label transfers its absorbed energy to the Rhodamine label, which then emits light according to its own characteristic fluorescence spectrum. When glucose is added to this solution, the FITC fluorescence intensity increases as FITCdextran is released from the RhConA and is replaced by glucose. Thus it is possible to determine glucose concentrations directly from the level of FITC fluorescence. One of the key elements in the diagnosis and manage-ment of disease is the measurement of (a) specific endogenous ubstances which either control homeo-static mechanisms or reflect the malfunction of these mechanisms and (b) the blood concentrations of drugs used to remedy the disorders. Most clinical analytical methods are based on techniques whic