AbstractThe authors describe an electrochemical immunoassay for ultrasensitive detection of the mycotoxin zearalenone (ZEA). A nanocomposite was prepared from carboxy-functionalized multi-walled carbon nanotubes and chitosan (cMWCNTs/Chit). The morphology and electrochemical performance of the materials was characterized by field-emission scanning electron microscopy, atomic force microscopy, differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy. In this assay, ZEA–BSA conjugated covalently to activated cMWCNTs/Chit film, then the indirect competition between ZEA–BSA and free ZEA when immobilization of excess anti-ZEA. The secondary antibody is labeled with the enzyme alkaline phosphatase which can hydrolyze the substrate 1-naphthylphosphate to produce 1-naphthol which gives a stable and strong anodic electrochemical signal at a low working voltage of 0.3 V (vs. Ag/AgCl). The use of the modified GCE results in a strongly enhanced electrochemical current response. Compared with conventional methods, the established immunosensor exhibited a high level of sensitivity. Under optimal conditions, this immunoassay can quantify ZEA in the 10 pg·mL−1 to 1000 ng·mL−1 concentration range with a detection limit of 4.7 pg·mL−1 and the sensitivity is 0.51 μA·μM−1·cm−2. The method was applied to the determination of ZEA in cereal and feedstuff samples. Results showed satisfactory recovery and good consistency with high-performance liquid chromatography. Therefore, the indirect competitive electrochemical immunosensor provide a viable tool based on bioanalysis. Graphical abstractA carboxylated multi-walled carbon nanotube and chitosan (cMWCNTs/Chit)-based immunosensor was designed for indirect competitive detection of zearalenone (ZEA). Competition between ZEA–BSA and ZEA occurs during immobilization of anti-ZEA. After incubation with AP-anti-antibody, DPV was conducted during addition of α-naphthyl phosphate (α-NP) to the DEA buffer.

中文翻译：

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基于羧化多壁碳纳米管和壳聚糖修饰的玻碳电极的电化学间接竞争免疫法超灵敏检测玉米赤霉烯酮

摘要作者描述了一种用于超灵敏检测霉菌毒素玉米赤霉烯酮 (ZEA) 的电化学免疫测定法。纳米复合材料是由羧基功能化的多壁碳纳米管和壳聚糖 (cMWCNTs/Chit) 制备的。通过场发射扫描电子显微镜、原子力显微镜、微分脉冲伏安法、循环伏安法和电化学阻抗谱对材料的形貌和电化学性能进行了表征。在该测定中，ZEA-BSA 与活化的 cMWCNTs/Chit 膜共价结合，然后当固定过量的抗 ZEA 时，ZEA-BSA 和游离 ZEA 之间发生间接竞争。二抗用碱性磷酸酶标记，碱性磷酸酶可以水解底物 1-萘基磷酸酯生成 1-萘酚，在 0.3 V（相对于 Ag/AgCl）的低工作电压下提供稳定且强的阳极电化学信号。使用改进的 GCE 会导致电化学电流响应大大增强。与传统方法相比，所建立的免疫传感器表现出高水平的灵敏度。在最佳条件下，该免疫测定法可在 10 pg·mL-1 至 1000 ng·mL-1 浓度范围内定量 ZEA，检测限为 4.7 pg·mL-1，灵敏度为 0.51 μA·μM-1·cm- 2. 该方法用于测定谷物和饲料样品中的 ZEA。结果显示出令人满意的回收率和与高效液相色谱法的良好一致性。所以，间接竞争电化学免疫传感器提供了一种基于生物分析的可行工具。图形摘要设计了一种基于羧化多壁碳纳米管和壳聚糖 (cMWCNTs/Chit) 的免疫传感器，用于玉米赤霉烯酮 (ZEA) 的间接竞争检测。ZEA-BSA 和 ZEA 之间的竞争发生在抗 ZEA 的固定过程中。与 AP 抗体孵育后，在向 DEA 缓冲液中加入 α-萘基磷酸酯 (α-NP) 期间进行 DPV。