pintasplasmonresonanssia

Pintasplasmonresonanssia, often referred to as Surface Plasmon Resonance (SPR) in English, is an optical phenomenon that occurs when light interacts with the free electrons at the surface of a metal. Specifically, it involves the collective oscillation of these conduction electrons, known as surface plasmons, being excited by photons of a specific wavelength and angle of incidence. This excitation leads to a dramatic decrease in the intensity of the reflected light at that particular resonance condition.

The phenomenon is highly sensitive to changes in the refractive index of the medium immediately surrounding the metal surface. When molecules bind to the surface of the metal film, they alter the local refractive index. This change, in turn, shifts the resonance condition, meaning a different wavelength or angle of light is required to achieve SPR. This sensitivity makes SPR a powerful label-free sensing technique.

SPR spectroscopy typically employs a prism to couple light into a thin metal film, often gold or silver. As the angle of incident light is varied, a dip in the reflected light intensity is observed when the surface plasmons are excited. The position of this dip, known as the resonance angle, is monitored. Any binding event on the metal surface will cause a measurable shift in this resonance angle, which can then be correlated to the concentration or amount of the analyte. SPR is widely used in biosensing, chemical analysis, and materials science due to its ability to detect molecular interactions in real-time without the need for labeling.