Detection Of Fusion Gene (b3a2) And Alpha-fetoprotein Based On SERS Spectroscopy

The discovery of surface enhanced Raman spectroscopy(SERS)has aroused widespread concern.It has extremely high detection sensitivity and can even detect single molecule under special conditions.At the same time,it has many advantages,such as stability,narrow half peak,rich information of material structure,short time and so on.This makes SERS very suitable for qualitative analysis and quantitative detection of substances.One of the important applications is to apply SERS technology to the detection of disease markers,cells and other components in medicine,which has made great progress in recent years.fusion gene(b3a2)is a marker of chronic myelogenous leukemia(CML),one of the hematological tumors.It has strong correlation,specificity,and high differentiation with chronic myelogenous.Alpha-fetoprotein(AFP)has strong correlation with liver cancer,because liver cancer cells can produce alpha-fetoprotein,but normal cells cannot produce it,so alpha-fetoprotein has important clinical value for the early detection,diagnosis,metastasis and prognosis of liver cancer.At the same time,the content of these two tumor markers in the human body is relatively low,so it needs a highly sensitive method to detect them.The SERS technology can just meet the detection standards of these two substances.In Chapter 2,we prepared our SERS substrate by assembling silver nanoparticles on silica wafers.We successively hydroxylated,aminated,and protonated the silica wafers,and then the silver nanoparticles were bound to the silica sheet through the Ag-N bond,and at the same time,the silver nano-particles and the modifier on the surface of the silica sheet have different charges,which improves the efficiency of assembly.In order to improve the performance of the two-dimensional SERS substrate,we optimized and improved the reaction conditions during the assembly process.In Chapter 3,we applied the prepared two-dimensional SERS substrate to the detection of fusion gene(b3a2).We divided the complementary sequence of the fusion gene(b3a2)into two segments,one was modified on a two-dimensional SERS substrate,and the other was modified on the uniformly dispersed silver nanoparticles in the solution and the fusion gene(b3a2)was cultured with them.Their complexes can be obtained through complementary base pairing,and the signals of signal molecules can be detected at the same time.According to the change of signal intensity,we can detect the fusion gene of(b3a2)quantitatively.In Chapter 4,we applied the prepared two-dimensional SERS substrate to the detection of alpha-fetoprotein.Using the ability of alpha fetoprotein to adapt to the specific binding of alpha fetoprotein,we first modified a-fetoprotein aptamer on two-dimensional SERS substrate,and the complementary sequence of aptamer was modified on silver nanoparticles dispersed in solution.Both of them can be cultured together to form complex through complementary base pairing,and at the same time,the signal of Raman labeled molecules can be detected.The addition of alpha fetoprotein will lead to the specific binding of aptamers to the aptamers,resulting in the decrease of signal intensity of Raman labeled molecules.The ultra-sensitive quantitative detection of alpha-fetoprotein was carried out according to the signal intensity variation of Raman-labeled molecules.In this paper,a uniform two-dimensional SERS substrate was prepared and applied to the quantitative detection of fusion gene(b3a2)and alpha fetoprotein.The experimental results show that our specially designed nanostructure combined with SERS technology can realize the quantitative detection of very low concentration tumor markers,including fusion gene(b3a2)and alpha fetoprotein,which provides a simple,efficient and rapid potential detection scheme for the quantitative detection of these two tumor markers.