Principles of Surface Plasmon Resonance

Abstract

BIACORE systems monitor surface-bound molecular interactions using surface plasmon esonance (SPR) to measure refractive index changes in solution close to the surface of a sensor (up to a istance of about 500 nm from the surface). Binding of molecules to the surface as a result of biospecific interaction changes the solute concentration in the surface volume, which influences the refractive index. The resulting change in the SPR signal is followed continuously in real time, resulting in direct monitoring of the molecular interaction process. Since the detection principle relies on changes in refractive index, no radioactive, optical, or enzymatic labels are required. The technique can be used to study all kinds of molecules including proteins and protein conjugates, carbohydrates, lipids, nucleic acids, small molecules such as pharmaceuticals, metabolites and effectors, and even larger particles such as viruses and whole cells.