Electrochemical Sensing of Neurotoxic Agents Based on Their Electron Transfer Promotion Effect on an Au Electrode
Electrochemical Sensing of Neurotoxic Agents Based on Their Electron Transfer Promotion Effect on an Au Electrode
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DOI：
10.1021/acs.analchem.6b04229
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发表时间：
2017-06-06
影响因子：
7.4
通讯作者：
Ihara, Toshihiro
中科院分区：
文献类型：
--
作者：
Shimada, Hiroshi;Noguchi, Shiori;Ihara, Toshihiro
报道了一种基于新原理的电化学分子传感器。沙蚕毒素（NRT，4-N，N-dimethylamino-1，2-dithiolane）是一种天然存在的神经毒素（烟碱乙酰胆碱受体激动剂），通过Au-S共价键吸附在Au电极上，加速了电极与标记物铁氰化物阴离子之间的电子转移。裸电极和NRT修饰的Au电极获得的电化学响应之间的对比在支持电解质KCl的低离子强度下更明显。在1 mM KCl的存在下，通过NRT的质子化叔氨基与铁氰化物阴离子之间的静电相互作用，获得了信号之间几乎为0/1的对比度。用巯基丙酸修饰的电极没有观察到电流。异常低的离子强度使双电层变厚到在裸电极下观察不到电流的程度。在这样的条件下，标记离子的静电浓缩的效果变得明显。在水解/还原预处理后，也使用相同的格式检测了市售的与NRT有关的农药，如杀螟丹和杀虫磺。该传感方法成功地应用于人血清，具有满意的灵敏度。
An electrochemical molecular sensor based on a new principle is reported. Nereistoxin (NRT, 4-N,N-dimethylamino-1,2-dithiolane), a naturally occurring neurotoxin (nicotinic acetylcholine receptor agonist), was adsorbed on an Au electrode via Au-S covalent bonding and accelerated the electron transfer between the electrode and the marker, ferricyanide anion. The contrast between the electrochemical responses obtained with the bare and NRT-modified Au electrodes was more pronounced at a low ionic strength of the supporting electrolyte, KCl. In the presence of 1 mM KCl, almost a 0/1 contrast between the signals was obtained through electrostatic interaction between the protonated tertiary amino group of NRT and the anionic ferricyanide ion. No current was observed with an electrode modified with mercaptopropionic acid. An unusually low ionic strength thickened the electric double layer to the degree where current was not observed with the bare electrode. The effect of the electrostatic concentration of the marker ion becomes obvious under such conditions. Commercially available NRT-related pesticides such as Cartap and Bensultap were also detected using the same format after pretreatments by hydrolysis/reduction. The present sensing method was successfully applied to human serum with satisfactory sensitivity.