A photoelectrochemical platform for thrombin determination was developed based on Au-rGO-CuS as multiple signal amplification elements. CuInS 2 QDs was used to sensitize burr-shape TiO 2 (b-TiO 2 ) to obtain a strong photocurrent. Under the specific recognition between aptamer and thrombin, a sandwichlike structure was formed and the Au-rGO-CuS-labeled aptamer (S2@Au-rGO-CuS) was immobilized on the electrode surface. This induced a sharp decrease in photocurrent. The phenomenon is mainly due to the fact that CuS NPs can competitively consume the light energy and electron donor with CuInS 2 /b-TiO 2 . The rGO can increase the amount of CuS NPs and the Au NPs can accelerate charge transferring which depress the recombination of photogenerated electrons and holes in CuS to further enhance the competitive capacity of CuS. The sandwichlike structure has a steric hindrance effect. Therefore, the S2@Au-rGO-CuS has a multiple signal amplification function for thrombin determination. Under optimal conditions, the PEC aptasensor exhibited a wide linear concentration range from 0.1 pM to 10 nM with a low detection limit of 30 fM (S/ N = 3) for thrombin. Besides, the designed aptasensor performed well in the assay of human serum sample, indicating good potential for the determination of thrombin in real samples. Graphical abstract

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基于 Au-rGO-CuS 作为信号放大元件的凝血酶光电化学适体传感器

基于 Au-rGO-CuS 作为多重信号放大元件，开发了用于凝血酶测定的光电化学平台。CuInS 2 QDs用于敏化毛刺状TiO 2 (b-TiO 2 )以获得强光电流。在适配体和凝血酶的特异性识别下，形成夹心结构，Au-rGO-CuS标记的适配体（S2@Au-rGO-CuS）固定在电极表面。这导致光电流急剧下降。这种现象主要是由于CuS NPs可以与CuInS 2 /b-TiO 2 竞争地消耗光能和电子供体。rGO 可以增加 CuS NPs 的数量，Au NPs 可以加速电荷转移，从而抑制 CuS 中光生电子和空穴的复合，进一步增强 CuS 的竞争能力。三明治状结构具有空间位阻效应。因此，S2@Au-rGO-CuS对于凝血酶测定具有多重信号放大功能。在最佳条件下，PEC 适体传感器表现出从 0.1 pM 到 10 nM 的宽线性浓度范围，凝血酶的低检测限为 30 fM (S/N = 3)。此外，所设计的适体传感器在人血清样品的测定中表现良好，表明在实际样品中测定凝血酶具有良好的潜力。图形概要 所设计的适体传感器在人血清样品的测定中表现良好，表明在实际样品中测定凝血酶具有良好的潜力。图形概要 所设计的适体传感器在人血清样品的测定中表现良好，表明在实际样品中测定凝血酶具有良好的潜力。图形概要