Preparation And Performance Studies Of Magnetic-Noble Metal Multifunctional SERS Substrate

In this thesis,Fe3O4/Au multifunctional composite SERS substrate materials,Fe3O4@Au-Apt multi functional composite SERS bio detection substrate materials:and Fe3O4@Cu2O-Au multifunctional composite SERS substrate materials were synthesized respectively.The micro structure,magnetic properties and Surface Enhanced Raman Scattering(SERS)properties of the materials were studied.The related physical and chemical mechanisms were revealed,and their application researches were explored.The research results obtained are as follows:(1)Fe3O4 nanoparticles with controlled size and fast magnetic response were successfully prepared by using an improved thermal decomposition method.The Fe3O4-Au core-satellite nano composites were successfully prepared by the Au seeds deposition method.Based on the Fe3O4-Au core-satellite nano composites,the Fe3O4@Au core-shell nano composites were further synthesized by seeds growth method.The microstructure,particle size and magnetic response of the Fe3O4/Au composite nanomaterials with two structures were systematically studied.In order to compare the SERS activities of Fe3O4/Au composite nanomaterials with two structures,this study used 4-aminothiophenol(4-ATP)as the SEERS active probe molecule.The study found that the Au shell structure can significantly increase the SERS activity of the material.In addition,this multi functional composite SERS substrate material with high SERS activity also exhibited rapid magnetic reactivity to external magnetic fields and had good SERS signal reproducibility.The SERS substrate showed excellent rapid detection ability in the application research of the actual detection of thiram on the apple skin.(2)The aptamer(Apt)was further modified on the surface of the Fe3O4@Au multifunctional composite SERS substrate materials,so that the Fe3O4@Au-Apt multifunctional composite SERS bio detection substrate materials were prepared.The physical and chemical properties of Fe3O4@Au-Apt composites were systematically studied.The research found that experimental factors such as the addition ratio of Fe3O@;Au composite to Apt,specific binding reaction time,and reaction temperature have important effects on the ability of Fe3O4@Au-Apt composite to detect Staphylococcus aureus(S.aureus).In a.ddition,the results of specific recognition experiments showed that the SERS bio detection substrate materials had outstanding specificity for S.aureus.Finally,Fe3O4@Au-Apt multifunctional composite SERS bio detection substrate materials were successfully used to detect S.aureus in milk.(3)Fe3O4@Cu2O composite nanomaterials were prepared by a simple and efficient one-step thermal decomposition method.The Fe3O4@Cu2O-Au multifunctional composite SERS substrate materials were further synthesized by in-situ reduction.The study found that the amount of Au nanoparticles on the surface of Fe3O4@Cu2O could be controlled by changing the amount of chloroauric acid soluion.With malachite green(MG)as the target,the effect of the loading of Au nanoparticles on the photo catalytic performance of Fe3O4@Cu2O-Au composite nanomaterials was studied.And the related photocatalytic degradation mechanism was revealed.The SERS activity of Fe3O@Cu2O-Au multifunctional composite SERS substrate materials were studied with fish growing in water with MG.This study successfully integrated photocatalytic degradation and SERS detection.This study not only successfully designed and prepared a variety of magnetic-noble metal multifunctional SERS substrate materials,but also achieved practical applications such as detection of pesticide residues on peels,detection of pathogenic bacteria in food,and detection and catalytic degradation of environmental pollutants.This Tesearch promotes the cross-disciplinary fusion of materials,physics,chemistry,and biology.It also lays a solid theoretical foundation and practical basis for studying scientific issues such as SERS enhancement mechanism,core-shell structure multifunctional composite interface interaction mechanism,and photocatalytic degradation of environmental pollutants.It provides new ideas and methods for the practical application research of SERS substrate.