Key Laboratory of Zoonoses Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun 130062, P. R. China.
College of Life Science, Yangtze University, Jingzhou 434023, P. R. China.
Anal Chem. 2021 Oct 19;93(41):13886-13892. doi: 10.1021/acs.analchem.1c02736. Epub 2021 Oct 8.
Given the great harm of pesticide residues to the environment and public health, exploring ultrasensitive and low-cost methods for their quantitative analysis becomes intensely necessary. Herein, we proposed a double-functionalized gold nanoparticle (AuNP) probe as a signal amplification immunoassay for the detection of acetochlor (ATC), metolachlor, and propisochlor. The AuNP was modified with IgG and fluorophore-labeled duplex DNA by a polyadenine-based freezing method. The quenched fluorescence can be effectively recovered via duplex-specific nuclease (DSN) with excellent cleaving activity. This approach provided limits of detection (LODs) down to 0.03 ng/mL for ATC, 0.10 ng/mL for metolachlor, 0.14 ng/mL for propisochlor, and 0.08 ng/mL for their mixture. The average recoveries of ATC, metolachlor, and propisochlor were 93.0-106.6% from a corn sample, which are in good agreement with the commercial kit ( = 0.9995). This "turn-off" fluorescence immunoassay presents considerable potential in the analysis of chloroacetamide herbicide due to its simple process of probe preparing and ultrahigh sensitivity.
鉴于农药残留对环境和公众健康的巨大危害，探索超灵敏和低成本的定量分析方法变得非常必要。在此，我们提出了一种双功能化的金纳米粒子（AuNP）探针，作为一种用于检测乙草胺（ATC）、异丙甲草胺和异丙草胺的信号放大免疫分析方法。通过基于多聚腺苷酸的冷冻方法，将 AuNP 与 IgG 和荧光标记的双链 DNA 进行修饰。通过具有优异切割活性的双链特异性核酸酶（DSN）可以有效地恢复被猝灭的荧光。该方法对 ATC 的检测限（LOD）低至 0.03 ng/mL，对异丙甲草胺的检测限（LOD）低至 0.10 ng/mL，对异丙草胺的检测限（LOD）低至 0.14 ng/mL，对它们的混合物的检测限（LOD）低至 0.08 ng/mL。在玉米样品中的 ATC、异丙甲草胺和异丙草胺的平均回收率为 93.0-106.6%，与商业试剂盒（r = 0.9995）非常吻合。由于探针制备过程简单且具有超高灵敏度，这种“关闭”荧光免疫分析方法在氯乙酰胺类除草剂的分析中具有很大的潜力。
