| In recent years,the incidence rate and mortality rate of malignant tumors have been increasing.Cervical cancer is the leading cause of cancer deaths among women in non developed countries.In China,the incidence rate of cervical cancer is high and high in female malignant tumors.The cause of this disease is related to age and human papillomavirus infection.Because cervical cancer is highly malignant and easy to metastasize and invade,the prognosis is poor.The early symptoms of cervical cancer is not obvious,it is easy to miss diagnosis,so early diagnosis of cervical cancer has great significance for the treatment and prognosis of cervical cancer.Squamous cell carcinoma associated antigen（SCCA）is a subunit glycoprotein of squamous cell carcinoma associated antigen isolated from cervical squamous epithelium.Its molecular weight is about 48 KD.It has two phenotypes:SCCA-1 and SCCA-2.SCCA can inhibit cell apoptosis and participate in the differentiation of squamous epithelium in normal squamous epithelial cells.When the number of malignant tumor cells increases,SCCA increases with it.Therefore,SCCA is often used as a biomarker for the detection of early cervical cancer.Its specificity in cervical cancer is even higher than 90%,which is better than other biomarkers.Surface enhanced Raman scattering（SERS）can enhance the Raman signal of the sample many times by adsorbing the sample on the metal nanoparticles or rough precious metal surface,so as to give the molecular structure at the molecular level,and some can even reach the level of single molecule detection.In this study,a highly specific,sensitive and reliable immunosensor for the detection of SCCA was developed based on surface enhanced Raman scattering（SERS）.Gold nanoparticles coated polydopamine resin microspheres（PDR@GNPs）.It was prepared and coupled with SCCA monoclonal antibody as capture substrate.Then,4-mercaptobenzoic acid（4-MBA）was used to adsorb hollow,high branched and polyhedral gold nanocages（GNCS）,and SCCA polyclonal antibody was used as SERS marker to modify them.The specific detection of SCCA was achieved by sandwich structure.The main research contents are as follows:（1）SERS enhanced materials can be prepared and assembled into corresponding capture substrates and SERS markersDopamine resin microspheres were prepared and modified with gold nanoparticles under controlled conditions to obtain PDR@GNPs.Then,by activating its surface carboxyl group,SCCA monoclonal antibody was modified on its surface to form SERS capture substrate（PDR@GNPs@resist SCCA@DMSA）.In the same way,gold nanocages were prepared.Under controlled conditions,the SCCA polyclonal antibody was absorbed by 4-MBA labeled GNCs by activating the carboxyl group on the surface of 4-MBA,so as to obtain SERS probes（anti-SCCA@GNs@4-MBA）.（2）SERS immunocomplex based on sandwich structure was used to detect tumor markersBased on this sandwich immunoassay strategy,SCCA polyclonal antibody combined with gold nanocage SERS labeling and SCCA monoclonal antibody combined with capture substrate were used to detect different concentrations of SCC antigen solution.The calibration curve was established in the range of SCCA concentration from 10-10M to 10-5M.The detection limit was 7.16 pg m L-1in PBS and 8.03 pg m L-1in human peripheral blood.Finally,according to the calibration curve,the new SERS immunosensor was applied to the quantitative detection of SCCA in cervical intraepithelial neoplasia（LSIL）,cervical intraepithelial neoplasia（HSIL）,cervical cancer and peripheral blood of healthy people.The results of enzyme-linked immunosorbent assay（ELISA）were consistent with the average value of SERS platform.The results show that the immunoassay based on SERS has a potential application prospect in the early screening and diagnosis of cervical cancer. |
PDF Full Text Request