Membrane-filter SERS Based Raman Spectroscopy Of Thyroid Tumor Plasma

Surface-enhanced Raman spectroscopy(SERS)is a molecular-level detection technique that enables specific discrimination between molecules at the molecular level.The application of SERS technology to the diagnosis of diseases in clinical medicine is expected to promote the further development of medical disease diagnosis technology.Based on the clinical diagnosis of thyroid tumors,this paper proposes a method based on the SERS technique to detect and analyze the plasma of patients with thyroid tumors.Combined with special data analysis methods,we attempt to develop a fast,simple non-invasive and accurate diagnostic method for differentiation of thyroid tumors as well as early tumor detection.The main work of this thesis is as follows:1.Firstly,the principles of conventional Raman scattering and surface enhanced Raman spectroscopy(SERS)are briefly introduced.Secondly,the research progress of SERS spectroscopy applied to human blood is summarized.Finally,the current status of SERS spectroscopy in the detection of thyroid-related diseases was reviewed.This thesis mainly uses SERS technology to conduct preliminary research on benign and malignant thyroid tumors that are difficult to differentially diagnose in clinical settings.2.Based on conventional blood detection by SERS technology,we carry out comprehensive optimization of SERS spectral signals.(1)Preparation of SERS-enhanced silver nanoparticle;(2)optimization of parameters of confocal Raman microscopy;(3)detection optimization by mixing silver nanoparticles and analytes in different proportions.Based on the optimization of the above various parameters,we obtained a reproducible and more stable SERS spectral signal,which laid the foundation for the subsequent SERS spectral detection research.3.We proposed a membrane filter SERS technology for the detection of thyroid plasma.That is to say,by using filter membranes with different pore sizes,the macromolecular proteins in plasma were filtered out,and the plasma samples werepretreated,the SERS spectra of the plasma filtrates treated with different membranes from102 patients with thyroid tumors(70 thyroid cancers and 32 thyroid benign tumors)were then obtained and compared.4.Multivariate statistical analysis of the obtained thyroid plasma SERS spectral data was conducted.SERS spectral data after background subtraction,with or without normalization(different normalization processing),as well as the first derivative processing of the SERS spectral data were tested and compared.Furthermore,PCA-LDA and Lasso-PLS-DA were used to analyze and compare the differential diagnosis of benign thyroid tumors and thyroid cancer.