ABSTRACT
Optical evanescent biosensors greatly facilitate the study of the interaction between a wide range of biomaterials. Since 1993 the resonant mirror (RM) as embodied in IAsys, has been used for work on eukaryotic and prokaryotic cells, viruses, liposomes, antibiotics, viruses, protein-coated latex and gold sols, polysaccharide, monosaccharide, bacterial toxins, antibiotics and vitamins, and the more conventional protein and nucleic acid binding studies. In principle the user links one of the interactants to the biosensor surface, adds the other interactant(s) and follows the binding response with time. With highly specific interactions, of reasonable affinity, measurements can be made in a realistic support medium, e.g. blood plasma. The optical ‘signal’ is generated by the change in refractive index as the binding species displaces water from the interrogated surface. In addition to revealing details such as the strength and rate of binary complex formation and dissociation, the order of assembly of higher complexes can be elucidated. This information will complement the high resolution structural data that is becoming increasingly available.
