The Preparation Of Membrane And The Aggregation Of Metal Nanoparticles And Its Application Used In Sers Spectra

Since the surface-enhanced Raman scattering （SERS） technology has been found,its mechanism and applications are always the research topic to which most peoplehave paid attention. At the moment, the SERS technology has been appliedcomprehensively in physics, chemistry, biology and material science research and soon. But the applications of SERS technology depend on the characteristics of theSERS substrates. So we need to prepare a novel type of substrates which have stablestructure, high SERS activity as well as good reproducibility of SERS spectra, and itis meaningful for expanding the application fields of SERS technologh and improvingthe research work quality. For this reason, in this thesis two different new SERSsubstrate based on the noble metal nanomaterials have been presented: thenanoparticle ordered films and nanoparticle aggregates, and those SERS substrateswill be effectively used in life science field to research biological molecules.This thesis chooses glutathione as one research object. At the same time, weprepared nanoparticle ordered films and nanoparticle aggregate as SERS substrate. Bycombining with nanotechnology, self-assembly technology and SERS technology, thenanoparticles ordered films assemebled on the surface of ITO glass were used as theSERS substrates to explore SERS measuring with low concentration of glutathionemolecules.This paper mainly covers the following aspects:（1） The brief introduction of Raman spectroscopy, the principles and theapplications of SERS technology, and the brief introduction of metallic nanomaterialsapplications in SERS techonology, in which emphasis has been put on the importanceof the substrates to the SERS measurment and the research status of the naoparticleordered films and nanoparticle aggregates.（2）60nm gold nanoparticles with uniform size and shape were prepared byhydroxylamine-two-step-seed-mediated-growing method. Uniform SERS substratesfeatured with highly dense and ordered assembled film of metallic nanoparticles wereprepared by assembling Au nanoparticles on the indium tin oxide （ITO） substrates which had been modified with （3-aminopropyl） trimethoxysilaine（APTES） previously.Then the orderly films have been cleaned by a plasma device under differentconditions. Furthermore pyridine and dithiodipyridine were selected as SERS probemolecules to evaluate the cleaning effect on SERS substrates in order to determine abetter cleaning conditions.（3） Select glutathione as the main research object, gold nanoparticles withuniform size and shape were synthesized by hydroxylamine seed-mediated two-stepgrowing method, and silver nanoparticles were synthesized by reducing silver nitratewith sodium citrate. SERS spectrocopic features of glutathione reduced formmolecules were characterized by using these Au and Ag nanoparticles ordered film asSERS substrates. It is significant that glutathione SERS detection limit is so low to thelevel10-13M when silver nanoparticles ordered films on ITO were used as SERSsubstrates.（4） The preparation conditions of Na₂S-Au NPs aggregates were experimentallyoptimized. The Na₂S-Au NPs aggregates prepared under such conditions show goodstability. As a comparison, we also prepared GSH-Au NPs aggregates，and selectedboth two aggregrates as the SERS substrates to characterize SERS spectra of severalamino acid molecules.All these work mentioned as above will help us to prepare SERS substrates withexcellent properties and these new SERS substrates can help us to characterize morebiological molecules effectively with SERS technique. Moreover it facilities us toinvestigate adsorption mechanism of biologically important molecules on such SERSsubstrate surface. It will also provide the effective approach and useful informationfor the research of structure–property relationships of relevant biomolecules in future.