Preparation Of Metallic Nanoparticles And Studies On The Interaction Of Nicotine With Bovine Serum Albumin By The SERS Spectrum

Surface-Enhanced Raman scattering(SERS) is a phenomenon which is occurred on the metallic nanostructures. When the molecule is placed on or near the surface of metallic nanostructures, the magnitude of Raman scattering signal could be enhanced greatly. So SERS has been a high sensitive analytical technique. In the study of the SERS enhancement, the physical properties of the metallic nanoparticles including their shape, size and composition have been the most important enhancement factors. The stability and SERS enhancement of the nanostructures strongly depend on those intrinsic properties, so the development of SERS is closely related to the metallic nanotechnology.On one hand, gold/silver nanostructures are easily dispersed and biocompatible; on the other hand, SERS which is an analytical technique with low aqueous interference is suitable for the detection in solution system. So these properties enable metallic nanoparticles-based SERS to be widely used in biomedical research field, especially in biomolecular analysis.The main achievements of this thesis are totally divided into four parts:1. Gold nanoparticles, silver nanoparticles and Au-Ag alloy nanoparticles are synthesized with citrate reducer and then Au@Ag core-shell nanoparticles are prepared when gold nanoparticles are used as seeds, and the character of those bimetallic nanoparticles is investigated by the SERS spectrum. Silver nanoparticles whose shape and diameter are kinichi are synthesized when PVP polmer mixture is protective agent. Non-spherical gold nanoparticles are synthesized by the seed-mediated growth, the stability and shape are investigated, and the results indicate that the shape of nanoparticles could change as the amount of AgNO3.2. IR and RS of nicotine are determined and its geometry is optimized as well as the vibrational spectrum is calculated by DFT/B3LYP using Gaussin03quantum chemistry programme. The result shows that the experimental values are in good agreement with the calculated ones. So the calculated geometry may be the best.3. The possible adsorption orientation and interaction behavior of nicotine on three adsorbing substrates—silver nanoparticles, gold-silver core-shell nanoparticles and gold-silver alloy nanoparticles are investigated respectively by the SERS spectrum. The result indicates that the molecule is adsorbed on the surfaces of the gold-silver alloy nanoparticles with a similar vertical adsorption orientation; however, as the surfaces of the silver and gold-silver core-shell are rich in Ag, the molecule employs an extremity adsorption orientation. Nicotine molecule interacts with the silver surface directly through the Ag-N bond.4. The reaction between bovine serum albumin (BSA) and nicotine is studied by the SERS spectrum, the effect of nicotine is studied and the changes of the interaction behavior of nicotine on gold nanoparticles are investigated. And then UV-Vis spectrum is employed to determine those changes.The results show that the second-level structure of BSA and the reaction between and gold nanoparticles both change.