Application Of Surface-enhanced Raman Spectroscopy In Diagnosis Of Lung Cancer

Due to the advantages of convenience,high efficiency,low cost and easy access,spectral technology has attracted much attention in the field of clinical diagnosis and analysis.Raman spectrum is a kind of molecular vibration spectrum.The Raman spectrum of every substance can reflect its own structural characteristics,so Raman spectrum is also called fingerprint spectrum.In this paper,the basic principle and application of the discovery and development of Raman spectroscopy(SERS)are introduced firstly,and the discovery and application of surface-enhanced Raman spectroscopy are introduced from Raman spectroscopy.In this paper,a kind of 3D substrate with high sensitivity and low cost for SERS was studied.The silver nanoparticles(Ag NPs)with a diameter of 40 nm were covered on the rough gold-plated monocrystalline silicon and prepared by hydrothermal method.The SERS enhanced effect of gold-plated and coarse-coated silicon thin layer silver nanoparticles and thick layer silver nanoparticles was studied by using finite difference time domain(FDTD)method to carry out electromagnetic calculation,and thhysical mechanism of the highly reinforced composite substrate was revealed.The,two methods of preparing Ag NPs,microwave method and hydrothermal method,were introduced in detail.The properties and applications of a SERS probe Rhodamine 6G(R6G)are introduced.R6 G was used as the probe to compare the Ag NPs prepared by the two methods,and it was found that the enhancement effect of the Ag NPs prepared by microwave method was more obvious,and then the lowest detection range of R6 G was detected by the Ag NPs prepared by microwave method.Finally,the application of SERS in lung cancer serum was studied,which ranks the top three among all cancers with high mortality rate.One of the important factors is that the early detection rate of lung cancer is too low,leading to many patients cannot be treated in time.Therefore,the early diagnosis of lung cancer has become a research hotspot.The Raman spectra and SERS of serum of patients with lung cancer were compared,indicating the enhancement effect of Ag NPs substrate on patients with lung cancer.The SERS of serum from 51 lung cancer patients and 18 normal subjects were collected using Ag NPs as the substrate.Principal Component Analysis(PCA)was used to classify lung cancer serum and normal serum,and it was found that the accuracy rate could reach 91.30%.Then,Partial least-squares discriminant(PLS-DA)was used to further analyze and distinguish the two serums,and the accuracy of model could reach 95.65% to achieve better classification.