Research On Preparation And Performance Of SERS Substrate Based On Gold Nanocomposite Structure

Surface Enhanced Raman Spectroscopy(SERS)is a kind of detection technology based on scattered light,which has the advantages of non-destructive,rich information contained and rapid detection,and attracted a large number of researchers to study SERS detection technology.The design and development of SERS substrate with stability,high sensitivity and clean surface is the key in the field of SERS detection.In this dissertation,through the design and preparation of gold nanocomposite structure,the preparation and performance of Au@SiO₂ core-shell nanoparticles substrate and gold nanothorns substrate were studied.Gold and silver nanoparticles are the most common SERS substrates.However,In the preparation of nanoparticles,surfactants are needed to maintain the stability of nanoparticles,and the presence of surfactants would interference the SERS detection.Therefore,this project utilizes mesoporous silica shell as the protective layer and synthesizes Au@SiO₂ core-shell nanoparticles with multiple gold nanoparticles inside,which effectively solves the interference of surfactant and the agglomeration of nanoparticles.In addition,aim at the complex and expensive preparation of SERS substrate,we designed a strategy to achieve gold nanothorns SERS chips,in which the preparation of SERS substrate can be done within 30 s,and the current strategy could meet the requirements of practical point-of-care testing application of SERS technology.In practical point-of-care testing applications,the samples to be tested are in a complex environment,and due to the label-free feature of SERS technology,the detection results are interfered by the Raman signal of impurities.Therefore,it is necessary to develop a SERS chips with specificity to meet the needs of point-of-care testing for specific analyte.SERS detection of specificity mainly accomplish by the identification and analysis of specific targets in complex environments through the specific interaction of biological enzymes and chemical molecules.In this project,we have combined biological enzymes and Au@SiO₂core-shell nanoparticles to prepare Raman SERS chips with specificity based on biological enzyme reaction,and achieved specific detection of glucose and uric acid.Moreover,we have developed a series of SERS chips by modifying the gold nanothorns'surface with Raman probes to achieve specific quantitative detection of hydrogen peroxide,nitrite ions,hypochlorite ions and pH.