REAL TIME BIA. A NEW BIOSENSOR BASED TECHNOLOGY FOR THE DIRECT MEASUREMENT OF BIOMOLECULAR INTERACTIONS

Abstract

This report descibes a system for real time biospecific interaction analysis, using biosensor technology based on the optical phenomenon surface plasmon resonance. The biospecific interface is a sensor chip consisting of a thin gold film deposited on a glass support and covered with a dextran polymer. One component of the interaction being studied is attached covalently to the dextran, and other interactants are passed over the sensor chip assisted by a flow injection liquid handling system. Sequential interactions can be followed in real time in terms of changes in the mass concentration of molecules at the sensor interface. Surface concentrations down to 10 pg/mm2 can be measured. Repeated analysis can be performed on the same sensor chip by regeneration of the specific interaction. With this system, the same general procedure can be used for a wide range analytical methodology including: 1) identification and classification, for example antigen specificity and antibody subclass classification 2) concentration and activity determination in crude samples 3) affinity ranking 4) determination of relative association and dissociation rate constants 5) label free detection of multiple sequential interactions, for example epitope mapping of antibody binding sites on an antigen.