Rapidity and high sensitivity are the critical factors for the diagnoses of heart attacks and cardiac troponin I (cTnI) is used as a gold standard marker for its diagnosis. To realize the accurate detection of cTnI, a novel ultrasensitive photoelectrochemical (PEC) immunosensor for cTnI determination was developed upon dual inhibition effect of [email protected]₂O core-shell submicron-particles(SPs) toward CdS sensitized the (001) facets of anatase titanium dioxide nanosheets (TiO₂/CdS). In this study, the TiO₂/CdS composite not only indicated stable and excellent photoelectric signal but also provided abundant functional group to immobilized cTnI antibodies (Ab₁). To obtain the high sensitivity, [email protected]₂O core-shell SPs were used as labels of the secondary antibodies (Ab₂), owning to competitive absorption of light and consumption of electron donor, less light energy and electron donors arrived at the TiO₂/CdS sensitization structure. Besides, the remarkable steric hindrance effect of [email protected]₂O core-shell SPs labeled secondary antibodies (Ab₂) conjugates obstructed the transfer of electrons and diffusion of the electron donors to the photoelectrode surface, leading to further decrease of photocurrent. Therefore, the constructed immunosensor has an ultrasensitive response to cTnI in a liner range of 0.02 pg/mL to 50 ng/mL with a low detection limit of 6.7 fg/mL, and exhibits good sensitivity and admirable stability. Moreover, the strategy provided an efficient and novel approach for dual inhibition effect in PEC immunoassay development.

快速和高灵敏度是诊断心脏病发作的关键因素，心脏肌钙蛋白I（cTnI）被用作诊断该疾病的金标准标记。为了实现cTnI的准确检测，基于[电子邮件保护的] ₂ O核壳亚微米颗粒（SPs）对CdS的双重抑制作用，开发了一种新型的cTnI测定用超灵敏光电化学（PEC）免疫传感器，使CtnI的（001）面敏化。锐钛矿型二氧化钛纳米片（TiO ₂ / CdS）。在这项研究中，TiO ₂ / CdS复合材料不仅显示出稳定且优异的光电信号，而且为固定化的cTnI抗体（Ab ₁）提供了丰富的官能团。为了获得高灵敏度，[电子邮件保护] ₂O核壳SPs被用作二抗（Ab ₂）的标记，因为它具有竞争性吸收光和消耗电子供体，较少的光能和电子供体到达TiO ₂ / CdS敏化结构。此外，[电子邮件保护的] ₂ O核-壳SP标记的二抗具有显着的位阻效应（Ab ₂）共轭物阻碍了电子的转移和电子供体向光电极表面的扩散，导致光电流进一步降低。因此，构建的免疫传感器对cTnI的响应在0.02 pg / mL至50 ng / mL的线性范围内，检测极限为6.7 fg / mL，显示出良好的灵敏度和令人称赞的稳定性。此外，该策略为PEC免疫测定开发中的双重抑制作用提供了有效且新颖的方法。