Surface plasmon resonance (SPR) allows real-time, label-free detection of biomolecular interactions. SPR occurs when polarized light strikes an electrically conducting surface at the interface between two media. This generates electron charge density waves called plasmons, reducing the intensity of reflected light at a specific angle known as the resonance angle, in proportion to the mass on a sensor surface. Biacore SPR systems are used primarily in pharmaceutical development, quality control, and basic life science research.
SPR is the basis of many standard tools for measuring adsorption of material onto planar metal (typically gold or silver) surfaces or onto the surface of metal nanoparticles. It is the fundamental principle behind many color-based biosensor applications, different lab-on-a-chip sensors and diatom photosynthesis.
In SPR, one molecular partner is immobilized on a metallic film. Light excites surface plasmons in the metal; when the binding partner binds to the immobilized molecule, this causes a detectable change in the surface plasmon signal.
