Duplex-Specific Nuclease-Triggered Fluorescence Immunoassay Based on Dual-Functionalized AuNP for Acetochlor, Metolachlor, and Propisochlor
Yonghong Zha, Yansong Li, Pan Hu, Shiying Lu, Honglin Ren, Zengshan Liu, Hualin Yang, Yu Zhou
Abstract
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 (R2 = 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.