The Preparation Of Ag@SiO₂and Its Application In Biological Membrane Used In SERS

Surface-enhanced scattering (SERS) effect refers to the adsorption on the surfaceroughness of metal compounds due to the local surface plasmons are caused by theelectromagnetic enhancement, as well as the rough surface on the atom clusters and itsadsorption on the molecules of Raman enhancement activity. Both of them cause greatlyenhanced Raman scattering effect on the determination of content. It has high sensitivity andhigh resolution, and also cannot be affected by water. Therefore it can provide abundantmolecular spectrum information, which can be widely used in the fields of chemical,biological and physical area. The strength of the raman scattering signal depends on not onlythe nature of the metal, but also the size of the nano structure, spacing and shape, especiallythe metal surface morphology and dielectric constant. So only a few of the nanoscale roughsurface of the metal or their nanostructures are of high SERS effect. Although SERStechnology has got wide application, preparation of the surface of the nanostructures is stillquite difficult to meet the requirements. Preparation of SERS substrate has been a highlight inresearch of surface enhanced Raman, and the preparation of the uniform, stable SERSsubstrate has always been the pursuit of many researchers. Nowadays, it was found that thecore-shell structure can avoid these drawbacks. Around the perimeter of the highly activeprecious metal particles, we wrap up a very thin and dense layer of SiO2film or Al2O3film.Thus, the problem of the poor universality of the SERS substrate and surface morphology hasbeen basically solved. In this paper, in order to enhance the Raman effectively, we use silvernanoparticles with a layer of SiO2(Ag@SiO2), which can prevent siliver particles togathered, but also does not affect the optical properties of the nucleus. Moreover, therepeatability of the chemical research on the surface of SiO2makes it easy for surfacemodification.We successfully synthesis Ag@SiO2using the two methods. Subsequently, we userhodamine and pyridine as probe to detect its enhancement effect. And Ag@SiO2with betterSERS enhancement effect has been used in the study of biological membrane.The main research contents and conclusions are as follows:To prepare a kind of shell isolated nanoparticles, we use high SERS activity of Ag nanoparticles surface wrapped a layer of chemical inertness shell. Then TEOS (SiO2) wasadded into silver sol solution. After continuous agitation, a layer of silica depositie to thesurface of silver nanoparticles, forming Ag@SiO2SERS base. The characterization ofAg@SiO2is detected by means of scanning electron microscopy (SEM), transmissionelectron microscopy (TEM),absorption and Raman spectra. Moreover, we use pyridinemolecules as a probe molecule to search the Raman enhancement effect with the Ag@SiO2.To prepare the Ag@SiO2SERS basement, we use sodium silicate solution in thenanosize silver particles wraped on a very thin layer of SiO2membrane. The characterizationof Ag@SiO2nanoparticles is detected by means of transmission electron microscopy (TEM),absorption and Raman spectra. Subsequently we use pyridine molecules and rhodamine asprobe molecule to research the SERS effect of Ag@SiO2with different thickness of silica.the SERS active best Ag@SiO2was used to investigate the SERS active of biologicalmolecules DPPC and DOPC membrane, its biological membrane molecular interactions wasstudied by means of Raman spectroscopy.