A MODEL SYSTEM FOR THE DEVELOPMENT OF AN OPTICAL BIOSENSOR BASED ON LIPID-MEMBRANES AND MEMBRANE-BOUND RECEPTORS

The reproducible and easy immobilization of receptors on sensor surfac es is a prerequisite for the development of receptor-based fibre optic biosensors. Using a fused silica fiber as the transducer, binding pro cesses of luminescently labeled ligands can be monitored by evanescent wave sensor (EWS) technology. The vesicle fusion technique was chosen for the immobilization of membrane-bound receptors in order to preser ve their binding specificity and activity, by embedding them in an env ironment similar to a lipid bilayer. The results of initial studies of repetitive cycles of lipid layer deposition and removal, indicating g ood reproducibility of lipid layer formation on the fiber, are present ed. Using the binding of fluorescently labeled streptavidin to a bioti nylated lipid layer as a model system for receptor-ligand interaction, good sensitivity, combined with low non-specific binding were observe d.