Technology Of Cancer Bioarkers Detection Based On SERS Immunoassay

Alpha-fetoprotein,carcinoembryonic antigen and prostate-specific antigen are commonly used as clinical cancer biomarkers,and have early screening and differential diagnosis for various cancers such as liver cancer,colon cancer and prostate cancer.Therefore,the study of rapid and simple methods to detect cancer biomarkers is of great significance for the early diagnosis of clinical cancer.In this study,a new lateral flow immunoassay(LFIA)based on surface-enhanced Raman scattering(SERS)was designed for highly sensitive and quantitative detection of alpha-fetoprotein(AFP),carcinoembryonic antigen(CEA),and prostate-specific antigen(PSA).Gold or silver nanorods were used as the SERS enhanced substrates,and a layer of bovine serum albumin(BSA)was coated on the surface to conjugated with antibodies to form SERS tags.SERS tags were assembled with immunochromatographic test strips to detect AFP,CEA and PSA.The main conclusions are as follows:1.The most suitable gold and silver nanorods were prepared via seed growth method,and characterized by TEM,UV-vis,Zeta potential,SEM and so on.The results show that the prepared gold and silver nanorods have uniform length,good dispersibility,and their resonance absorption peaks match the given excitation wavelength,and have high SERS performance.2.The prepared AuNRs modified Raman molecules were covered with a layer of BSA,and a SERS-LFIA detection method based on AuNRs was established.Firstly,it was determined that the BSA layer was wrapped on the surface of the nanorod and coupled with the antibody.Secondly,the immunochromatographic conditions were optimized,and it was found that using a sample solution containing 20% FBS in PBST buffer(1%Tween-20)to perform chromatography on the nitrocellulose membrane of HF135 can make the SERS signal reach the best state.Finally,the SERS immunochromatographic test strip was used to detect human Ig G,and the detection limit can reach 0.1 ng/m L,indicating that the SERS immunochromatography method we designed was feasible for rapid detection.3.SERS-LFIA based on AuNRs was used to detect sensitivity,specificity,repeatability and clinical samples of AFP,CEA and PSA.The visualization result of the detection of AFP is 10 ng/m L and the detection result of SERS is 0.01 ng/m L;the visualization result of CEA detection is 10 ng/m L and the result of SERS detection is 0.01 ng/m L;the visualization result of PSA detection is 1 ng/m L,and the SERS detection result is 0.001ng/m L.The detection of SERS-LFIA strips of three cancer biomarkers showed good stability,specificity and selectivity.4.SERS-LFIA detection method based on Au@Ag NRs was used to detect AFP and CEA,AFP and PSA,and CEA and PSA.In the simultaneous detection of AFP and CEA,the detection limit of SERS for AFP is 0.0005 ng/m L and the limit of detection of SERS for CEA is 0.001 ng/m L;in the simultaneous detection of AFP and PSA,the detection limits for SERS of AFP and PSA are both 0.0005 ng/m L;in the simultaneous detection of CEA and PSA,the detection limit of SERS detection of CEA and PSA is 0.0005 ng/m L.The combined detection of cancer biomarkers by Au@Ag NRs-based SERS-LFIA strip shows high sensitivity,as well as their specificity and selectivity for target biomarkers.