In this work, a peptide-based photoelectrochemical (PEC) biosensor was constructed based on CdTe/TiO2 sensitized structure as electrode and CuS nanocrystals as signal amplifier for the ultrasensitive detection of protein. After peptide was fixed to the CdTe/TiO2 electrode surface, the double-helix DNA (dsDNA) was immobilized at the end of the peptide and used as a carrier to immobilize the doxorubicin-copper sulfide nanocrystals (Dox-CuS) conjugates. As a proof of concept, prostate specific antigen (PSA) has been chosen as the model. In absence of PSA, CuS nanocrystals could consume electron donors and exciting light energy. Additionally, the steric hindrance effect of biomacromolecules hindered the movement of electron donors to the photoelectrode. Eventually, the photoelectric response signal was reduced, and the biosensor was in a "signal off" state. When PSA existed, the PSA specifically cleaved the peptide, and DNA/Dox-CuS probes were released from the electrode surface, resulting in a "signal on" state. The PEC biosensor revealed good specificity, stability, and reproducibility, and it exhibited excellent application in PSA analysis with a linear range from 0.005 to 20 ng mL-1 and a low detection limit of 0.0015 ng mL-1. This PEC biosensor may have potential applications in bioanalysis, disease diagnostics, and clinical biomedicine.

中文翻译：

---

肽裂解介导的光电化学信号通过CuS电子灭火器进行开/关，用于PSA检测。

在这项工作中，基于CdTe / TiO2敏化结构作为电极和CuS纳米晶体作为信号放大器构建了基于肽的光电化学（PEC）生物传感器，用于蛋白质的超灵敏检测。在将肽固定到CdTe / TiO2电极表面后，将双螺旋DNA（dsDNA）固定在肽的末端，并用作载体来固定阿霉素-铜-硫化铜纳米晶体（Dox-CuS）共轭物。作为概念的证明，已选择前列腺特异性抗原（PSA）作为模型。在没有PSA的情况下，CuS纳米晶体会消耗电子供体和激发光能。另外，生物大分子的空间位阻效应阻碍了电子供体向光电极的移动。最终，光电响应信号降低，生物传感器处于“ 它在PSA分析中显示出出色的应用，线性范围为0.005到20 ng mL-1，检测限很低，为0.0015 ng mL-1。这种PEC生物传感器在生物分析，疾病诊断和临床生物医学中可能具有潜在的应用。它在PSA分析中显示出出色的应用，线性范围为0.005到20 ng mL-1，检测限很低，为0.0015 ng mL-1。这种PEC生物传感器在生物分析，疾病诊断和临床生物医学中可能具有潜在的应用。