Pesticides and their metabolites threaten the environment and human health even at low concentrations. Therefore, the development of sensors to track such substances is crucial. Nanoparticle-based sensors have been widely used recently as a possible substitute analytical tool to traditional pesticide detection techniques. Artificial enzymes, also known as enzyme mimics or nanozymes, are gaining attention due to their innate ability to overcome the limitations of natural enzymes and their efficacy to be sufficient for upcoming advancements in treatments and diagnostics. Nanozyme-based assays may enable organophosphate pesticide detection without relying on the natural cholinesterase enzymes while retaining similar or higher sensitivity at a lower cost. Therefore, the present work investigates the acetylthiocholine (ATCH) hydrolyzing ability of gold nanorods (GNRs) through colorimetric, computational, and electrochemical methods. The GNRs were observed to intrinsically exhibit ATCH hydrolyzing ability, like acetylcholine esterase (AChE). Further, the effect of different organophosphates (OPs) (malathion, methyl parathion, chlorpyrifos, parathion, and dichlorvos) on the ATCH hydrolyzing ability of nanostructures was studied using an electrochemical approach. Their activity was significantly quenched in the presence of malathion and methyl parathion as compared to other OPs. The increasing order of OP's inhibitory effect was malathion>methyl parathion>dichlorvos>chlorpyrifos>parathion. It was observed that inhibition was proportional to the increasing concentration of OPs, and the linear range of detection was 0.0005-200.0 µg mL-1, with a limit of detection (LOD) of 8.1 pg mL-1 and 30.2 pg mL-1 respectively, for malathion and methyl parathion. Validation of river water samples spiked with different concentrations of malathion shows good recovery in the range of 100–110 %. Keywords: Acetylthiocholine; Cyclic Voltammetry; Electrochemical; Nanozyme; Organophosphate; Gold nanorod

中文翻译：

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研究金纳米棒介导的乙酰硫胆碱水解：一种有机磷农药电化学检测方法


即使在低浓度下，农药及其代谢物也会威胁环境和人类健康。因此，开发用于跟踪此类物质的传感器至关重要。基于纳米颗粒的传感器最近被广泛用作传统农药检测技术的可能替代分析工具。人工酶，也称为酶模拟物或纳米酶，因其克服天然酶局限性的先天能力以及足以满足即将到来的治疗和诊断进展的功效而受到关注。基于纳米酶的分析可以在不依赖天然胆碱酯酶的情况下实现有机磷酸盐农药检测，同时以较低的成本保持相似或更高的灵敏度。因此，本工作通过比色、计算和电化学方法研究了金纳米棒 （GNR） 的乙酰硫胆碱 （ATCH） 水解能力。观察到 GNR 本质上表现出 ATCH 水解能力，如乙酰胆碱酯酶 （AChE）。此外，使用电化学方法研究了不同有机磷酸盐 （OPs） （马拉硫磷、甲基对硫磷、毒死蜱、对硫磷和敌敌畏）对纳米结构 ATCH 水解能力的影响。与其他 OP 相比，在马拉硫磷和甲基对硫磷存在下，它们的活性显着淬灭。OP 的抑制作用的递增顺序为马拉硫磷>methyl parathion>dichlorvos>chlorpyrifos>parathion。观察到抑制与 OPs 浓度的增加成正比，线性检测范围为 0.0005-200.0 μg mL-1，马拉硫磷和甲基对硫磷的检测限 （LOD） 分别为 8.1 pg mL-1 和 30.2 pg mL-1。 对加标不同浓度马拉硫磷的河水样品的验证表明，在 100–110% 的范围内具有良好的回收率。关键词：乙酰硫胆碱;循环伏安法;电化学;纳米酶;有机 磷;金纳米棒