IN-SITU OBSERVATION OF STREPTAVIDIN-BIOTIN BINDING ON AN IMMUNOASSAY WELL SURFACE USING AN ATOMIC-FORCE MICROSCOPE

Polystyrene microtitre wells are commonly used as supports for the enz yme-linked immunosorbent assay (ELISA) method of biomolecular detectio n, which is employed in the routine diagnosis of a variety of medical conditions, We have used an atomic force microscope (AFM) to directly monitor specific molecular interactions between individual streptavidi n and biotin molecules on such wells. This was achieved by functionali sing an AFM probe with biotin and monitoring the adhesive forces betwe en the probe and a streptavidin coated immunoassay well. The results d emonstrate that the AFM may be employed as an analytical tool to study the interactions between biomolecules involved in immunoassay systems .