Wang Shengfu, Zhang Xing, Mao Xun, Zeng Qingxiang, Xu Hui, Lin Yuehe, Chen Wei, Liu Guodong
Department of Chemistry and Molecular Biology, North Dakota State University, Fargo, ND 58105, USA. College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, People's Republic of China.
Nanotechnology. 2008 Oct 29;19(43):435501. doi: 10.1088/0957-4484/19/43/435501. Epub 2008 Sep 22.
We describe a lead sulfide nanoparticle (PbS NP)-based electrochemical immunoassay to detect a tumor biomarker, carcinoembryonic antigen (CEA). Cubic PbS NPs were prepared and functionalized with thioglycolic acid (TGA), which stabilized the formed NPs and offered carboxyl groups to conjugate with CEA antibodies. PbS NP conjugated with monoclonal CEA antibody was used as a label in an immunorecognition event. After a complete sandwich immunoreaction among the primary CEA antibody (immobilized on the carboxyl-modified magnetic beads), CEA and the PbS-labeled secondary antibody (PbS-anti-CEA), PbS labels were captured to the magnetic-bead (MB) surface through the antibody-antigen immunocomplex. Electrochemical stripping analysis of the captured PbS was used to quantify the concentration of CEA after an acid-dissolution step. The MBs and the magnetic separation platform were used to integrate a facile antibody immobilization with immunoreactions and the isolation of immunocomplexes from reaction solutions in the immunoassay. The voltammetric response is highly linear over the range of 1-50 ng ml(-1) CEA, and the limit of detection is estimated to be 0.5 ng ml(-1). The performance of this nanoparticle-based electrochemical immunoassay was successfully evaluated with human serum spiked with CEA, indicating that this convenient and sensitive technique offers great promise for rapid, simple and cost-effective analysis of tumor biomarkers in biological fluids.
我们描述了一种基于硫化铅纳米颗粒（PbS NP）的电化学免疫分析法，用于检测肿瘤生物标志物癌胚抗原（CEA）。制备了立方晶型的PbS NPs并用巯基乙酸（TGA）进行功能化修饰，TGA可使形成的纳米颗粒稳定，并提供羧基以便与CEA抗体结合。与单克隆CEA抗体结合的PbS NP用作免疫识别事件中的标记物。在固定于羧基修饰磁珠上的初级CEA抗体、CEA和PbS标记的二级抗体（PbS-抗CEA）之间发生完全的夹心免疫反应后，通过抗体-抗原免疫复合物将PbS标记物捕获到磁珠（MB）表面。在酸溶解步骤之后，对捕获的PbS进行电化学溶出分析以定量CEA的浓度。磁珠和磁分离平台用于在免疫分析中整合简便的抗体固定、免疫反应以及从反应溶液中分离免疫复合物。伏安响应在1-50 ng ml(-1) CEA范围内呈高度线性，检测限估计为0.5 ng ml(-1)。用添加了CEA的人血清成功评估了这种基于纳米颗粒的电化学免疫分析法的性能，表明这种便捷且灵敏的技术在生物流体中肿瘤生物标志物的快速、简单且经济高效的分析方面具有巨大潜力。
