Department of Chemistry, Chemical Engineering and Environmental, Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, P. R. China.
ACS Appl Bio Mater. 2024 Aug 19;7(8):5258-5267. doi: 10.1021/acsabm.4c00438. Epub 2024 Aug 5.
Sensitive detection of cardiac troponin I (cTnI) is of great significance in the diagnosis of a fatal acute myocardial infarction. A redox-active nanocomposite of copper(II)-tannic acid@Cu (CuTA@Cu) was herein prepared on the surface of a glassy carbon electrode by electrochemical deposition of metallic copper combined with a metal stripping strategy. Then, HAuCl was in situ reduced to gold nanoparticles (AuNPs) by strong reductive catechol groups in the TA ligand. The AuNPs/CuTA@Cu composite was further utilized as a bifunctional matrix for the immobilization of the cTnI antibody (anti-cTnI), producing an electrochemical immunosensor. Electrochemical tests show that the immunoreaction between anti-cTnI and target cTnI can cause a significant reduction of the electrochemical signal of CuTA@Cu. It can be attributed to the insulating characteristic of the immunocomplex and its barrier effect to the electrolyte ion diffusion. From the signal changes of CuTA@Cu, cTnI can be analyzed in a wide range from 10 fg mL to 10 ng mL, with an ultralow detection limit of 0.65 fg mL. The spiked recovery assays show that the immunosensor is reliable for cTnI determination in human serum samples, demonstrating its promising application in the early clinical diagnosis of myocardial infarction.
灵敏检测心肌肌钙蛋白 I（cTnI）对于致命性急性心肌梗死的诊断具有重要意义。本文通过电化学沉积金属铜结合金属剥离策略，在玻碳电极表面制备了一种氧化还原活性纳米复合材料铜（II）-鞣酸@铜（CuTA@Cu）。然后，通过 TA 配体中强还原性儿茶酚基团将 HAuCl 原位还原为金纳米粒子（AuNPs）。AuNPs/CuTA@Cu 复合材料进一步用作固定 cTnI 抗体（抗-cTnI）的双功能基质，产生电化学免疫传感器。电化学测试表明，抗-cTnI 与靶标 cTnI 之间的免疫反应会导致 CuTA@Cu 的电化学信号显著降低。这可以归因于免疫复合物的绝缘特性及其对电解质离子扩散的阻碍作用。从 CuTA@Cu 的信号变化可以分析出 cTnI 在 10 fg mL 到 10 ng mL 的宽范围内的浓度，检测限低至 0.65 fg mL。加标回收率测定表明，该免疫传感器可用于人血清样品中 cTnI 的可靠测定，表明其在心肌梗死的早期临床诊断中有很好的应用前景。
