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通过表面增强拉曼散射(SERS)标记抗体检测结肠癌组织切片上癌胚抗原(CEA)的表达,探讨SERS标记免疫检测技术用于临床分析结肠癌组织切片中蛋白质表达的可行性。采用种子生长法合成Ag壳Au核复合纳米粒子,将4-巯基苯甲酸(4-MBA)作为标记分子吸附于纳米粒子表面,制备出SERS探针;再将这种探针与CEA单克隆抗体相结合形成SERS免疫探针;最后通过SERS标记的抗体与结肠癌组织切片上相应的抗原发生特异性结合,对滴加探针的组织切片进行SERS检测和成像。结肠癌腺上皮出现很强的SERS信号,而除了少数非特异性吸附产生的信号之外,间质及正常上皮中几乎不出现SERS信号。通过SERS成像可以清晰地看到结肠癌腺上皮显示红色,表明结肠癌腺上皮高表达CEA,而间质及正常上皮几乎显示黑色和深蓝色,只有极个别点为红色,表明间质及正常上皮基本不表达CEA。研究表明,SERS标记抗体检测分析技术具有高灵敏度和高特异性,有望应用于结肠癌组织切片中蛋白质表达的分析,成为结肠癌辅助诊断的一种重要方法。
The expression of carcinoembryonic antigen (CEA) on colon cancer tissue sections was detected by surface enhanced Raman scattering (SERS) labeling antibody, and the feasibility of SERS labeling immunoassay for the clinical analysis of protein expression in colon cancer tissue sections was explored. The Ag shell Au core composite nanoparticles were synthesized by seed growth method, and 4-mercaptobenzoic acid (4-MBA) was used as the labeled molecule to adsorb on the surface of the nanoparticles to prepare SERS probe. Then this probe was conjugated with CEA monoclonal antibody Finally, the SERS-labeled antibody was specifically bound to the corresponding antigen on the colon cancer tissue section, and SERS detection and imaging were performed on the tissue sections of the probe. The colon adenocarcinoma showed a strong SERS signal, and there was almost no SERS signal in the interstitial and normal epithelium except for the signals generated by a few nonspecific adsorption. The colon adenocarcinoma shows a red color through SERS imaging, indicating that the colon glandular epithelium has high CEA expression, whereas the mesenchyme and normal epithelium show almost black and dark blue with only a few red spots, indicating that stroma and normal epithelium The basic does not express CEA. Studies have shown that SERS-labeled antibody detection and analysis technology with high sensitivity and specificity, is expected to be applied to the analysis of protein expression in colon cancer tissue sections, as an important method of colon cancer diagnosis.