Abstract A novel signal-off photoelectrochemical (PEC) biosensing platform based on hybridization chain-doped manganese porphyrin quenching on PEC signal of CdSe quantum dots (QDs) coupling with cyclic amplification was developed for thrombin detection. Target thrombin firstly induced DNA enzyme-aided cyclic amplification reaction and produced abundant DNA I. Then DNA I hybridized with capture DNA on the TiO2/CdSe QDs modified electrode to form DNA bridge, which triggered a linear chain hybridization reaction with S4 and S5. Numerous manganese porphyrin (MnPP) were doped in the long double-stranded DNA chain, which hindered electron transfer and resulted in obvious decrease of QDs PEC signal, achieving a sensitive detection of thrombin. This PEC biosensor exhibits excellent performance with a wide linear range from 1.0 fM to 100.0 nM and detection limit of 0.331 fM, and the recovery value ranged from 95.5% to 103.5%. The results suggest that this PEC biosensor has high sensitivity and precision, showing great application prospect in microbiological analysis of biomolecules and clinical medicine.

中文翻译：

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基于杂交链掺杂锰卟啉猝灭 CdSe 信号耦合循环放大的信号关闭光电化学生物传感平台用于凝血酶检测

摘要 开发了一种新型的信号关闭光电化学（PEC）生物传感平台，该平台基于杂化链掺杂锰卟啉对 CdSe 量子点（QD）的 PEC 信号的猝灭与循环放大耦合，用于凝血酶检测。靶凝血酶首先诱导DNA酶辅助循环扩增反应，产生大量DNA I。然后DNA I与捕获DNA在TiO2/CdSe QDs修饰电极上杂交形成DNA桥，引发与S4和S5的线性链杂交反应。大量的锰卟啉（MnPP）掺杂在长双链DNA链中，阻碍了电子转移，导致QDs PEC信号明显降低，实现了对凝血酶的灵敏检测。这种 PEC 生物传感器表现出优异的性能，线性范围从 1.0 fM 到 100。0 nM，检测限为 0.331 fM，回收率范围为 95.5% 至 103.5%。结果表明，该PEC生物传感器具有较高的灵敏度和精密度，在生物分子的微生物分析和临床医学方面具有广阔的应用前景。