AbstractThe authors describe a sensitive electrochemical immunoassay for the cancer biomarker α-fetoprotein (AFP). It is based on a combination of an immunoassay with DNA-based signal amplification. Two-dimensional MnO2 nanosheets modified with gold nanoclusters (AuNC-MnO2) were synthesized through one-pot process and utilized as an electrochemical probe. Bovine serum albumin served as templating agent to guide the formation and assembly of the modified sheets. The detection antibody against AFP and a polycytosine DNA sequence (dC20) were immobilized onto the modified nanosheets. The electrochemical assay follows the usual sandwich protocol. The antibodies on the nanosheets then bind to AFP, while dC20 causes signal amplification. The reaction of the phosphate backbone of dC20 with molybdate leads to the formation of redox-active molybdophosphate which generates an electrochemical current, typically measured at 0.20 V (vs. Ag/AgCl). The method allows AFP to be determined in the 0.01 to 10 ng·mL−1 concentration range, and the detection limit is as low as 5 pg·mL−1. This strategy overcomes the drawbacks of conventional immunoassays whose sensitivity is often limited because many immunoassays are rather difficult to amplify. The method has a wide scope in that various other DNA signal amplification methods such as rolling circle amplification and hybridization chain reactions may also be applied. Graphical abstractSchematic of an electrochemical immunosensor for the detection of alpha fetoprotein (AFP) by combining an antibody based immunoassay with DNA based signal amplification utilizing gold clusters anchored 2D MnO2 (Au NCs-MnO2) nanosheets as electrochemical probe.

中文翻译：

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使用经 MnO2 纳米片和金纳米团簇修饰的电化学探针将基于抗体的识别与基于 DNA 的信号放大偶联：应用于癌症生物标志物甲胎蛋白的灵敏伏安测定

摘要作者描述了一种用于癌症生物标志物甲胎蛋白 (AFP) 的灵敏电化学免疫分析。它基于免疫分析与基于 DNA 的信号放大的组合。通过一锅法合成了用金纳米团簇 (AuNC-MnO2) 修饰的二维 MnO2 纳米片，并将其用作电化学探针。牛血清白蛋白作为模板剂指导改性片的形成和组装。针对 AFP 的检测抗体和多胞嘧啶 DNA 序列 (dC20) 被固定在修饰的纳米片上。电化学测定遵循通常的夹心协议。然后纳米片上的抗体与 AFP 结合，而 dC20 会导致信号放大。dC20 的磷酸盐骨架与钼酸盐的反应导致形成具有氧化还原活性的钼磷酸盐，其产生电化学电流，通常在 0.20 V（相对于 Ag/AgCl）下测量。该方法可测定 0.01 至 10 ng·mL-1 浓度范围内的 AFP，检测限低至 5 pg·mL-1。这种策略克服了传统免疫测定法的缺点，其灵敏度通常有限，因为许多免疫测定法很难放大。该方法的适用范围很广，还可以应用滚环扩增、杂交链反应等各种其他DNA信号放大方法。