Department of Clinical Laboratory, the Third Affiliated Hospital, Chongqing Medical University, Chongqing 401120, P.R. China.
Analyst. 2018 Mar 12;143(6):1454-1461. doi: 10.1039/c7an02091k.
Methods based on potentiometric measurement have been developed for immunoassays, but most exhibit low sensitivities and are unsuitable for early diagnosis of disease. Herein we design a new potentiometric immunosensing platform for the sensitive detection of carcinoma antigen 15-3 (CA 15-3) by coupling with enzymatic biocatalytic precipitation and a nanogold labeling technique. The sandwich-type immunoreaction is carried out on a monoclonal anti-CA 15-3 capture antibody-modified working electrode, using horseradish peroxidase (HRP) and polyclonal anti-CA 15-3 detection antibody-labeled gold nanoparticles. Upon the introduction of target CA 15-3, the carried HRP molecules with an immunocomplex catalyze the oxidation of 4-chloro-1-naphthol (4-CN) into the insoluble benzo-4-chlorohexadienone. The formed product coated on the surface of the modified electrode results in a change of the electrical potential. Under optimal conditions, the shift in the electrical potential relative to the background signal increases with the increasing target CA 15-3 concentration, and exhibits a good linear relationship within the dynamic range of 0.01-30 U mL at a detection limit of 7.8 mU mL. Good precision and reproducibility, and high specificity were acquired for the analysis of 15 human serum specimens, giving well matched results with those obtained from a human CA 15-3 ELISA kit.
方法基于电位测量已被开发用于免疫分析，但大多数表现出低灵敏度，不适合疾病的早期诊断。在这里，我们设计了一种新的电化学免疫传感平台，通过与酶催化沉淀和纳米金标记技术相结合，用于敏感检测癌抗原 15-3（CA 15-3）。夹心型免疫反应在单克隆抗 CA 15-3 捕获抗体修饰的工作电极上进行，使用辣根过氧化物酶（HRP）和多克隆抗 CA 15-3 检测抗体标记的金纳米粒子。在引入靶 CA 15-3 后，带有免疫复合物的携带 HRP 分子催化 4-氯-1-萘酚（4-CN）氧化成不溶性苯并-4-氯己二烯酮。在修饰电极表面形成的产物导致电位发生变化。在最佳条件下，相对于背景信号的电位变化与目标 CA 15-3 浓度的增加成正比，并在检测限为 7.8 mU mL 时在 0.01-30 U mL 的动态范围内表现出良好的线性关系。对 15 个人血清标本进行分析时，获得了良好的精密度和重现性以及高特异性，与从人 CA 15-3 ELISA 试剂盒获得的结果非常吻合。
