Surface Plasmon Resonance (SPR)

SPR is the established gold standard for label-free macromolecular interaction analysis. It involves immobilization of a target molecule (e.g. protein or nucleic acid) on a sensor chip, followed by addition of its binding partner. Polarized light excites surface plasmons on the thin gold sensor film; when partner molecules bind to the immobilized target, the local mass change shifts the resonance angle in real time. Recording association and dissociation as sensorgrams gives binding rate constants and affinity.