surface plasmon resonance

Surface plasmon waves are electron waves created at metal surfaces. When biomolecules are attached to the surface, these waves can be used to monitor binding reactions because of changes in refractive index of the solvent near the surface.

Because the binding responses in SPR instruments are essentially based on mass, the reactants do not need to be labeled with fluorescent or radioactive probes.

Common configuration of SPR instruments use either a prism (A) or a grated surface (B) to defract light.