Lu Tian, Wang Liping, Xia Yuhong, Jin Yang, Zhang Liying, Du Shuhu
School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu 211166, China.
Analyst. 2021 May 4;146(9):3016-3024. doi: 10.1039/d1an00121c.
Carcinoembryonic antigens (CEAs) are known as one of the most common tumor markers. Their facile and affordable detection is critical for early diagnosis of malignant tumors, especially in resource-constrained settings. Here, we report a novel multimer-based surface-enhanced Raman scattering (SERS) aptasensor for a specific CEA assay. The aptasensor is fabricated through aptamer-assisted self-assembly of silver-coated gold nanoparticles (Au@Ag NPs), and the self-assembled multimeric structure possesses abundant hot-spots to provide high SERS response. When CEA is introduced, the specific recognition of CEA by aptamers will lead to the disassembly of Au@Ag multimers due to the lack of a bridging aptamer between Au@Ag NPs. As a result, the number of hot-spots in the multimeric system is decreased, and the intensity at 1585 cm-1 of the SERS reporter (4-mercaptobenzoic acid, 4-MBA) on the surface of NPs will also be decreased. The Raman intensity is proportional to the logarithm of the concentration of CEA. The detection sensitivity can be down to the pg mL-1 level. The analytical method only needs a droplet of 2 μL of sample, and the detection time is less than 20 min. The multimer-based SERS aptasensor can be applied in sensitive and inexpensive detection of CEA in serum samples.
癌胚抗原（CEA）是最常见的肿瘤标志物之一。其简便且经济的检测对于恶性肿瘤的早期诊断至关重要，尤其是在资源有限的环境中。在此，我们报道了一种用于特异性CEA检测的新型基于多聚体的表面增强拉曼散射（SERS）适配体传感器。该适配体传感器通过适配体辅助的银包金纳米颗粒（Au@Ag NPs）自组装制备，自组装的多聚体结构具有丰富的热点以提供高SERS响应。当引入CEA时，由于Au@Ag NPs之间缺乏桥连适配体，适配体对CEA的特异性识别将导致Au@Ag多聚体的解离。结果，多聚体系统中的热点数量减少，并且NP表面上SERS报告分子（4-巯基苯甲酸，4-MBA）在1585 cm-1处的强度也将降低。拉曼强度与CEA浓度的对数成正比。检测灵敏度可低至pg mL-1水平。该分析方法仅需2 μL样品液滴，检测时间少于20分钟。基于多聚体的SERS适配体传感器可应用于血清样品中CEA的灵敏且廉价检测。
