School of Agricultural Engineering and Food Science, Shandong University of Technology, No. 12 Zhangzhou Road, Zibo 255049, China.
School of Agricultural Engineering and Food Science, Shandong University of Technology, No. 12 Zhangzhou Road, Zibo 255049, China; Shandong Provincial Engineering Research Center of Vegetable Safety and Quality Traceability, No. 12 Zhangzhou Road, Zibo 255049, China.
Sci Total Environ. 2020 Apr 10;712:136410. doi: 10.1016/j.scitotenv.2019.136410. Epub 2019 Dec 30.
In order to solve the problem that the sensor cannot be reused due to the passivation of the electrode surface, a refreshable electrochemical aptasensor based on a hydrophobic electrode and a magnetic nanocomposite had been developed. Therein, the hydrophobic electrode was formed by modifying a screen-printed carbon electrode (SPCE) with polydimethylsiloxane (PDMS), which could avoid adsorption of molecules on the electrode surface due to its hydrophobicity. Combined with aptamer (Apt), the synthesized graphene oxide-ferroferric oxide (GO-FeO) was used as a magnetic catcher to capture specific organophosphorus pesticides (OPs), which could be removed to the working area of SPCE with a magnet for electrochemical detection. The performance analysis of hydrophobic electrode showed that the SPCE could be used twice. When the electrochemical signals of Apt/GO-FeO and OPs/Apt/GO-FeO were recorded using the same SPCE, the current differences between them were directly related to the concentrations of OPs. Through the contrast test between the spiked vegetable samples and the OPs standard solutions, it was found that the OPs concentrations could be qualitatively evaluated by comparing the current differences. At the same time, the characteristic of collecting target with magnetic catcher was helpful for detecting OPs with a low concentration. Therefore, the refreshable aptasensor provided a huge potential to small molecule target evaluation.
为了解决由于电极表面钝化导致传感器无法重复使用的问题，开发了一种基于疏水电极和磁性纳米复合材料的可刷新电化学适体传感器。其中，疏水电极是通过用聚二甲基硅氧烷 (PDMS) 修饰丝网印刷碳电极 (SPCE) 形成的，由于其疏水性，可避免分子在电极表面的吸附。结合适体 (Apt)，合成的氧化石墨烯-四氧化三铁 (GO-FeO) 被用作磁性捕获剂来捕获特定的有机磷农药 (OPs)，可以用磁铁将其转移到 SPCE 的工作区域进行电化学检测。疏水电极的性能分析表明，SPCE 可以重复使用两次。当使用相同的 SPCE 记录 Apt/GO-FeO 和 OPs/Apt/GO-FeO 的电化学信号时，它们之间的电流差异与 OPs 的浓度直接相关。通过对加标蔬菜样品和 OPs 标准溶液的对比测试，发现通过比较电流差异可以定性评估 OPs 的浓度。同时，磁性捕获剂收集目标物的特性有助于检测低浓度的 OPs。因此，可刷新的适体传感器为小分子目标物的评估提供了巨大的潜力。
