Abstract：
In this study, a novel electrochemical aptamer sensor for detecting ochratoxin A (OTA) was constructed. First, a gold-copper alloy film was prepared via electrochemical deposition, and copper was selectively dissolved in constant potential mode for obtaining the nano-porous gold modified screen-printed carbon electrodes (NPG/SPCE). Then, 2-mercaptoethylamine was dropped on the NPG/SPCE surface and Au-S covalent bonds were formed for immobilizing the metal. Glutaraldehyde as cross-linking agent was added, which resulted in immobilization and attachment of PAMAM to the 2-mercaptoethylamine through the dehydration condensation reaction. During the preparation process, the nano-porous gold and PAMAM-modified layers were characterized by SEM, XRD, and IR spectroscopy, respectively. The characterization results showed that the nano-porous gold and PAMAM composite films were successfully modified. Finally, the OTA aptamer was cross-linked with PAMAM by glutaraldehyde to complete construction of the Apt/PAMAM/NPG/SPCE sensor. The electrochemical performance of this sensor was tested in ochratoxin A solutions with the DPV method. The results showed that the sensor\'s reproducibility, stability, and specificity were good. The spiked recoveries in red wine ranged from 99.65%∼101.6%, with a linear range of 0.5 ng/mL∼20 ng/mL and a minimum detection limit of 0.141 ng/mL. Thus, the novel biosensor may provide a promising tool for the trace detection of OTA.
摘要：
在这项研究中,构建了一种新型的电化学适配体传感器，用于检测曲霉毒素A（OTA）。首先,通过电化学沉积制备了金铜合金膜，以恒电位模式选择性溶解铜，获得纳米多孔金修饰的丝网印刷碳电极（NPG/SPCE）。然后，将2-巯基乙胺滴在NPG/SPCE表面上，并形成Au-S共价键以固定金属。加入戊二醛作为交联剂，这导致PAMAM通过脱水缩合反应固定并连接到2-巯基乙胺上。在准备过程中,通过SEM对纳米多孔金和PAMAM修饰层进行了表征,XRD,和红外光谱，分别。表征结果表明，纳米多孔金和PAMAM复合薄膜被成功修饰。最后,通过戊二醛将OTA适体与PAMAM交联以完成Apt/PAMAM/NPG/SPCE传感器的构建。用DPV方法在曲霉毒素A溶液中测试了该传感器的电化学性能。结果表明，该传感器的重现性，稳定性,特异性很好。红酒的加标回收率在99.65%~101.6%之间，线性范围为0.5ng/mL~20ng/mL，最低检测限为0.141ng/mL。因此，这种新型生物传感器可能为OTA的痕量检测提供有前途的工具。
