Optical Biosensor in the Study of Biorecognition Processes

The elucidation of biological processes deserves the understanding of the basic forces that determine the involved molecular recognition phenomena. The characterization of these interactions determines a growing need of methodologies for studying any specific biomolecular event as well as the structural elements that drive the process. In order to determine the equilibrium and/or kinetic constants for binding, these techniques must factor the concentrations of free probe and target molecules, as well as of the corresponding complex. A recent development in instruments that investigate biomolecular interactions is the optical biosensor, which detects molecules with high selectivity on the basis of molecular recognition. Here we report the use of optical biosensors in the investigation of different biomolecular systems. First the methodology was used for the investigation of the drugs and diagnostic agents interactions with lipid membranes and plasma proteins, giving valuable information on the absorption and distribution of the compounds. The technique allowed both effective screening of compounds and detailed kinetic and mechanistic analysis of specific interactions. The current strategy resulted then useful for the detection of structural features of importance for the ADME (absorption, distribution, metabolism and excretion) issue. The protein was covalently immobilized on the surface of the biosensor, while fresh liposomes were immobilized by capturing on the surface before each sample injection. The optical biosensor was then successfully applied to the characterization of the molecular interactions between herpes simplex virus (HSV) cellular receptors and glycoproteins showing receptor-binding activity. These studies are of great relevance for understanding the glycoprotein-mediated interference to infection and then to get information on the mechanism(s) involved in the virus entry. The real time measurements allow the kinetic of the binding process to be fully characterized. Finally the optical biosensor was proved suitable for high throughput screening in the identification of ligands, biomarkers, and target proteins. Optical biosensor surely represents a suitable technique for monitoring biorecognition processes. The miniaturization and automation of the system, together with the short analysis time, make the optical biosensors of high potential in the discovery and development of new drugs.