Surface plasmon resonance (SPR) and Biacore systems.
Surface plasmon resonance (SPR) is an optical phenomenon used to measure the interaction of biomolecules. Biacore instrumentation utilises surface plasmon resonance to allow biomolecular interaction analysis in real time without the need for labels. Detection and analysis of bimolecular interactions is of considerable interest across a wide range of research fields including academic, biotechnology and pharmaceutical sectors. The ability to measure these interactions is beneficial for a wide range of applications in particular for both diagnostics and therapeutics.
Diagram: Surface plasmon resonance-based biosensor
Surface plasmon resonance occurs when polarised light is passed through a prism and undergoes total internal reflection at a metal surface of a sensor chip and liquid interface. The light energy excites plasmons in the metal surface causing them to oscillate and resonate. As plasmons absorb incident light energy, a decrease in the intensity of the reflected light is observed by the optical detection unit.
Biacore technology exploits this methodology by using a gold sensor chip immobilised with ligand and passing over analyte in solution. As analyte binds to the immobilised ligand a change in mass at the metal surface occurs. This binding interaction perturbs the resonating plasmons and this change is recognised by the optical detection unit as a decrease in the intensity of reflected light. Biacore instrumentation uses this information to produce sensogram graphs which can provide results and data on the biomolecular interactions of a variety of molecules. Data produced by Biacore technology allows the screening and characterisation of binding molecules, determination of kinetic rates and determination of binding affinity.
There is a rich history of antibody-antigen interaction analysis within the BDI including low molecular weight compounds which can be analysed to provide important information for drug discovery and therapeutic development.