Surface plasmon resonance detection formats

The use of protein microarrays has also made a big impact in the study of protein-protein interactions. In this method, thousands of proteins are spotted in a microarray format at known locations on a chip, then the solution of the target protein is spread on the chip. Interacting proteins are detected by fluorescent imaging, surface plasmon resonance, or mass spectrometry.174-177... 

Surface Plasmon Resonance Imaging Whereas most of the technologies we have discussed so far are only developing, SPRi has been available for quite some time, offering quantitative, label-free, robust, and economical interaction detection in a high-throughput format (Fig. 2-11) [36]. Although RIfS and EIS may provide data types similar to those of this technique, SPRi has been commercialized and subsequently developed for routine practical applications much... 

The ultraviolet (UV) - visible spectrophotometer is another important tool in the characterisation of vegetable oil-based polymer nanocomposites and is particularly effective for metal nanocomposites. The formation of metal nanoparticles in the matrix can be easily detected by UV-visible spectroscopy. Every metal nanoparticle has its own characteristic surface plasmon resonance value. This band is attributed to the collective oscillation of electron gas in the nanoparticles, with a periodic change in the electronic density at the surface. Parameters such as particle size, shape and dielectric constant of the medium and surface adsorbed species determine the position and shape of the plasmon absorption. When the particles become significantly smaller than the mean free path of electrons in the bulk metal, the plasmon oscillation is dampened. The plasmon absorption peak shifts to a higher wavelength than expected with an increase in aggregation of the nanoparticles. The sharpness of the peak indicates the narrow size distribution. 

Surface plasmon resonance is a very sensitive optical technique. However, the maximum sensitivity that can be obtained in several applications is limited by the amount of analyte or the molecular weight of those directly binded or adsorbed to the surface of the SPR substrate. Thus, the detection of small molecules can be carried out using a different strategy. Most often, small molecules are detected in a sandwich, competition or inhibition assay format [27-29]. 

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