Construction And Intelligent Raman Sensing Performance Of Metal Micro/Nanostructure

Surface Enhanced Raman Spectroscopy（S ERS）not only has extremely rich chemical fingerprint information in Raman spectroscopy,but also can obtain high sensitivity through plasmon-enhanced excitation and scattering.The application of SERS technology in the field of sensing analysis involves interaction of plasmonic nanomaterials with biologica l systems or complex environments.Therefore,in order to extract meaningful information from SERS data,stable and reliable processing technology and multifunctional probe structures have become key issues for intelligent detection.We will solve several major problems in Raman sensing applications as the starting p oint,such as the problem of single probe structure,complex preparation procedures and active Raman detection problems,etc.While achieving high-sensitivity detection,it provides possibilities for molecular detection in complex environments and clinical biomedical applications.In this paper,we briefly outline the theory of SERS enhancement including chemical and electromagnetic field enhancement mechanisms,propose the core-shell structure of mesoporous silica-coated metal particles and metal spine-like structures as Raman probes,and design different intelligent detection applications.Firstly,we have prepared metallic nanodots encapsulated hollow mesoporous silica nanoparticles（Metal@Si O₂）with adjustable metallic components inside.The sacrificial template of polystyrene（PS）nanoparticles pre-coated with metals（Au/Ag/Pt）is fully wrapped with mesoporous silica（m Si O₂）.The metallic nanodots are formed during the template removal process by calcination.The type and content of the encapsulated na nodots can be readily and precisely controlled by the initially deposited metallic layers.We designed the application of hollow mesoporous silica structures based on loaded gold（Au）nanodots as smart SERS probes,with the aid of Raman reporter,the SERS probe can successfully quantify H₂O₂,which is used to distinguish cancer cells in vitro.Also,the probe can screen between macromolecules and small analytes in a complex system environment,and solves the"protein corona"that plagues Raman probes in the field of biomedical detection.Secondly,on the basis of the above core-shell structure,we prepare a temperature-responsive micro-sampling nanoprobe by encapsulating metal（Au）nanodots inside hollow mesoporous silica nanoparticl es（HMSNP）and grafting temperature-responsive polymer Poly（N-isopropylacrylamide）（PNIPAM）on their external surface.The molecular gate of nano-channels accessing the internal hollow reservoir can be switched between"Close"and"Open"states by regulating the temperature,allowing on-demand loading and releasing of small molecules.The internally embedded surface enhanced Raman scattering hotspots of gold nanodots can serve as sensing probes for real-time detection of the molecular cargo loading inside the hollow nanorobots.Furthermore,we demonstrate temperature dependent self-propulsion behavior of the nanoprobes driven by enzymatic reactions.The active motion behavior can favorably regulate the loading efficiency of molecular cargos.In addition,by further introducing magnetic component,the nanorobots can accomplish effective transportation of cargo molecules by magnetic guidance under the real-time Raman monitoring.This new type of Raman probe is expected to provide an operable micro/nano platform for precise biomedical sampling and detection,making up for the insufficient maneuverability of traditional passive Raman detection probes.Finally,the availability of SERS substrates with good stability,high sensitivity and clean surface are crucial for the practical usefulness of SERS technology in biochemical sensing,especially for point-of-care testing（POCT）.Hereby,we develop a"ready-to-use"SERS kit,which requires only 20 s to fabricate ultraclean gold nanothorns（Au NT）based SERS chip under ambient condition with simple solution processing steps.By varying the th ickness of the pre-coated platinum（Pt）nanolayer,we can control the size and number density of the grown Au NT.And we put forward the scheme of SERS detection kit,combined with smartphone Raman analyzer,to realize the determination of Bacillus biomarkers in environmental water source and human serum.At the same time,by integrating remote data terminals and medical resources,the application potential of this method in environmental protection or online medical systems is demonstrated.Using this Au NT SERS chip with ultra-clean surface,the detection and identification of cancer cells were realized after modification of Raman reporter molecules.In addition,an anti-tumor diagnosis and treatment platform based on Au NT chips was further constructed.By imparting magnetism to the nanothorn structure,an active nanocarrier for tumor-targeted mechanotherapy and photothermal synergisti c therapy was designed.The problem of multifunctional integration of diagnosis and treatment in the field of anti-tumor in the medical field provides a new idea.In summary,this paper mainly aims at the structural design and practical detection application requirements of Raman probes,designs an d prepares Raman-enhanced detection probes based on two metal composite structures,and studies the Raman-enhanced nanocore-shell structure and thorn-like structure.The preparation process of the detection probe,and the systematic research work on the application of Raman-enhanced sensing and detection has been carried out.The research results will provide new ideas for the development of stable,reliable,easy-to-prepare and multifunctional Raman probe materials,as well as new materials and diagnostic technology support for the diagnosis and treatment of major clinical diseases.