Preparation And Characterization Of SERS Substrate Based On Tumor Cell Detection

Raman spectroscopy can provide the molecular"fingerprints"and provide the detailed information of the molecular structure.In most cases,Raman scattering is very weak,but the discovery of surface enhanced Raman scattering?SERS?has greatly expanded the application of Raman spectroscopy in the analysis field.The preparation of SERS substrate with a high sensitivity,a high reproducibility and a high homogeneity is of great importance to enrich the application of SERS in the analysis field.The achievement of SERS in biological science is particularly outstanding.Miniaturized and portable optical fiber based SERS sensors have been used in remote sensing and in vivo detection.Microfluidic chips have offered a powerful platform for the application of SERS in the biological field.Microfluidic technique has many advantages like small volume,high flux,integrated and miniaturized,and highly automated characteristics.A highly sensitive SERS substrate based on tumor cell detection has been developed on hollow core fibers and microfluidic channels in this thesis.It can be used for the detection of Raman molecules with a low detection limit and even single cell detection.The features of nanomaterials and solid substrates were characterized by UV-vis extinction spectra,scanning electron microscope?SEM?,transmission electron microscope?TEM?and other technologies.In the experiments,SERS substrates based on spherical silver nanoparticles and gold@silver core-shell?Au@Ag?nanorods were fabricated via electrostatic self-assembly method on single mode quartz optical fibers,hollow core fibers and microfluidic chip channels,respectively.The substrates showed a great SERS enhancement with a high stability and can be used to detect R6G as low as 1 nM.Besides,even label-free detection of tumor cells was also achieved at single-cell level.Furthermore,a composite SERS substrate based on spherical silver nanoparticles and Ti₃C₂T_x nanosheets were also prepared in the microfluidic channel,which exhibited a great SERS enhancement.The above experimental results provide new ideas for the design of SERS substrates.