Plasmon resonance biological applications

The use of optical immune biosensors based on surface plasmon resonance (SPR) for the diagnostics of human and animal diseases as well as for environmental pollution monitoring, is one of prospective directions in biosensorics. The sensitivity of immune biosensors is similar to the ELIS A-method but the simphcity of obtaining results in the real time regime and the speed of the analysis are the main advantages of the biosensor approach. Performance of optical biosensors based on SPR depends on the state of the metallic surface as well as on the density, structure and the space volume of the immobilized molecules. It was demonstrated that the application of intermediate layers between the transducer surface and the sensitive biological molecules can optimize the working characteristics of the immune biosensor [7-14]. 

Salmon, Z., et al. (1997), Surface plasmon resonance spectroscopy as a tool for investigating the biochemical and biophysical properties of membrane protein system. II. Application to biological system, Biochim. Biophys. Acta, 1331,131-152. 

In the last few decades, metal clusters and nanomaterials have attracted increasing attention due to their unique properties which differ from those of the bulkd Metal nano-objects are of great interest in the field of nanosciences. They are the ideal structures for fundamental research and applications. Indeed, from the confinement of the charge carriers in such limited objects, one expects a shift of the plasmon resonance absorption, non-linear optical effects, non-metallic conductivity, and nanocatalytic effects. Nanomaterials can have important applications in several fields such as catalysis, electrocatalysis, electronics, optical limitation, biology, etc. 

Metal nanoparticles have attracted considerable interest due to their properties and applications related to size effects, which can be appropriately studied in the framework of nanophotonics [1]. Metal nanoparticles such as silver, gold and copper can scatter light elastically with remarkable efficiency because of a collective resonance of the conduction electrons in the metal (i.e., the Dipole Plasmon Resonance or Localized Surface Plasmon Resonance). Plasmonics is quickly becoming a dominant science-based technology for the twenty-first century, with enormous potential in the fields of optical computing, novel optical devices, and more recently, biological and medical research [2]. In particular, silver nanoparticles have attracted particular interest due to their applications in fluorescence enhancement [3-5]. 

Once chemoenzymatically produced, these unnatural sialosides have demonstrated utility in a variety of biological applications. A sialoside consisting of 9-0-acetylated sialyl Tn antigen (sTn) was produced by one-pot synthesis and conjugated to human serum albumin to be used to evaluate the role of acetylation in carbohydrate-protein interactions. Para-nitrophenol-tagged sialosides can be used in a colorimetric assay to evaluate sialidase specificity. Biotin-tagged sialosides have been immobilized on a streptavidin-coated surface to study protein-carbohydrate interactions with surface plasmon resonance techniques. Size-defined... 

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