AbstractThe authors describe a method for the colorimetric determination of the pesticide malathion. It is based on the use of a hairpin structure consisting of a complementary strand of aptamer and a double-stranded DNA (dsDNA) structure to protect gold nanoparticles (AuNPs) against salt-induced aggregation. In the absence of malathion, the dsDNA structure is preserved on the surface of AuNPs and the color of the AuNPs in solutions containing NaCl remains red. However, in the presence of malathion, a hairpin structure of complementary strand is formed. The Aptamer/Malathion complex and the complementary strand are released from the surface of the AuNPs. As a result, the AuNPs undergo salt-induced aggregation which is accompanied by a color change to blue. The assay allows malathion to be quantified within 35 min (A650/A520 was measured). The detection limit is 1 pM, and response is linear in the 5 pM to 10 nM malathion concentration range. The method is specific and was successfully applied to the determination of malathion in spiked human serum samples. Graphical abstractSchematic representation of detection of malathion based on dsDNA-modified gold nanoparticles (AuNPs) and the hairpin structure of the complementary strand.

中文翻译：

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基于适体互补链的靶诱导发夹结构组装的马拉硫磷比色金纳米颗粒聚集测定

摘要 作者描述了一种农药马拉硫磷的比色测定方法。它基于使用由适配体互补链和双链 DNA (dsDNA) 结构组成的发夹结构来保护金纳米粒子 (AuNPs) 免受盐诱导的聚集。在没有马拉硫磷的情况下，dsDNA 结构保留在 AuNPs 的表面，并且 AuNPs 在含有 NaCl 的溶液中的颜色保持红色。然而，在马拉硫磷的存在下，形成互补链的发夹结构。适体/马拉硫磷复合物和互补链从 AuNP 的表面释放。结果，AuNPs 经历盐诱导的聚集，伴随着颜色变为蓝色。该测定允许在 35 分钟内对马拉硫磷进行定量（测量了 A650/A520）。检测限为 1 pM，响应在 5 pM 至 10 nM 马拉硫磷浓度范围内呈线性。该方法特异性强，已成功应用于加标人血清样品中马拉硫磷的测定。图形摘要基于 dsDNA 修饰的金纳米粒子 (AuNP) 和互补链的发夹结构检测马拉硫磷的示意图。