Structure Controllable Preparation Of Gold And Silver Nanomaterials And The SERS Application In Extracellular PH Imaging

Surface Enhanced Raman Spectroscopy(SERS)is a highly sensitive and selective molecular vibration spectroscopy,which is widely used in the field of analysis and detection.However,there are still some problems in SERS detections,such as poor quantitative performance,reproducibility and stability.Therefore,the preparation of stable SERS substrates with high sensitivity and the development of reliable SERS quantitative detection methods are significancant to the development and application of SERS technology.Au and Ag nanomaternals have been widely used in SERS substrates because of their Localized Surface Plasmon Resonance(LSPR),which can enhance Raman signals on the surface of nanoparticles.This thesis is aimed at developing the stable SERS substrates and improving the accuracy of SERS quantitative detection.We are devoted to researching on the new gold and silver nanomaterials and studying their cellular applications in SERS detection.The main works are as follows:(1)A flow irradiation device was designed.Based on the reshaping and restructuring of nanoparticles by pulsed laser,the perfectly spherical 60 nm,95 nm,130 nm Au NPs and 120 nm,200 nm Au-Ag alloy nanoparticles(Au@Au-Agalloy NPs)were contFollablly batch prepared with this device.The perfectly spherical Au NPs and Au@Au-Agalloy NPs had smooth surface and nearly spherical morphylogy,which had potential applications in the theoretical research on SERS and the SERS substrates with high uniformity.(2)After the dealloying treatment,the cage-like porous gold nanoparticles(Au@cAu NPs)with special structure of cage-like porous gold shell coating gold core were prepared.The individual LSPR scattering and the FDTD calculation showed that the porous gold shell is not closely attached the gold core in some of the Au@cAu NPs,and there is the gap of about 10 nm between the core and shell.The porous shell can increase the "hot spots" through the interaction between the porous shell and core,and most of the"hot spots" are distributed in the gap.What's more,it was found that the solid SERS substrates of Au@cAu NPs had certain SERS performance and could be applied in the detection of Malachite Green(the lowest detectable concentration was 0.1 ppm).(3)Au@pMBN@Ag@Au NPs(CMSS NPs)which can improve the accuracy of SERS detection by the correction of internal standard were prepared.With the specific binding between functionally modified CMSS NPs and MUC1 protein on cell membrane,the extracellular pH detection and imaging of breast cancer cells(MCF-7)and cervical cancer cells(CASKI)were realized,which had important reference value for the study of physiological and pathological processes in cancer cells.And we found that the extracellular pH of these two kinds of cells in neutral environments is about 6.7,and the extracellular pH is lower than the environmental pH.