SPR

The Biacore technology allows real-time detection and monitoring of biomolecular binding events. In a Biacore experiment, one of the interacting molecules (the ligand) is bound to the biosensor surface (sensor chip), whereas the other (the analyte) is delivered to the surface in a continuous buffer flow through a microfluidic system. Binding to the immobilized molecule is followed by surface plasmon resonance (SPR), which detects mass changes at the sensor surface. Recording SPR signal variation as a function of time (sensorgram) for several analyte concentrations allows to determine the association and dissociation rate constants, and to derive the affinity constant. This technology also allows to measure the concentration of functional molecules and the interaction stoichiometry.
The Biacore technology is used to characterize molecular interactions involving small molecules, proteins, polysaccharides, lipids and nucleic acids. Sequential injections of several interactants make possible the mapping of interaction domains and the determination of the composition and of the mechanism of assembly of multiprotein complexes.

See more at:

http://www.isbg.fr/biophysics-characterisation/spr-biacore-technology/