surface plasmon resonance

^ http://purl.obolibrary.org/obo/MI_0107

This method measures formation of complex by monitoring changes in the resonance angle of light impinging on a gold surface as a result of changes in the refractive index of the surface. A ligand of interest (small molecule, peptide, protein, sugar, lipid, nucleic acid) is immobilized on a gold surface, and the interacting partner is injected in buffer flow over it. Biomolecules that interact with the immobilized ligand are retained on the surface, and alter the resonance angle of impinging light as a result of the change in refractive index brought about by the increased biomolecule mass retained on the surface. Since all the biomolecules belonging to the same class have the same refractive index and since there is a linear correlation between resonance angle shift and biomolecule concentration near the surface, this allows one to measure changes in concentration at the surface as a consequence of interaction. Furthermore, this is done in real time, allowing direct measurement of both the on-rate and the off-rate and of the affinity constant of complex formation. [ http://www.ncbi.nlm.nih.gov/pubmed/12120258 http://www.ncbi.nlm.nih.gov/pubmed/11896282 http://www.ncbi.nlm.nih.gov/pubmed/16338355 ]

Synonyms: BIAcore(r), spr, Optical biosensor