Target-driven ratiometric electrochemical aptasensor based on polymerization and AuNP signal amplification for...

Acetamiprid (ACE), a next-generation chlorinated neonicotinoid insecticide, has been extensively employed for pest control. However, its excessive residues in food and the environment have raised significant concerns regarding human health. To address the need for a simple, accurate, and efficient ACE detection method, a novel ratiometric aptamer sensor was developed based on the dual signal amplification strategy of atom transfer radical polymerization (ATRP) and gold nanoparticles (AuNPs). The internal reference system was established by the electrostatic adsorption/embedding interaction of methylene blue (MB) with double-stranded deoxyribonucleic acid (dsDNA), and the reaction site was expanded using AuNPs loaded with multiplexed DNA₂ sequences, which was combined with the in situ grafting of conductive polymers by ATRP to achieve signal multiplication. Under the optimized conditions, the sensor exhibited good linearity in the range 70 pg/mL ~ 300 ng/mL with a detection limit of 19.26 pg/mL. During the real sample analysis, the sensor revealed remarkable stability, reproducibility, and sensitivity in the detection of ACE residues in food. The design principle of such a sensor provides a reliable tool for accurate monitoring of pesticides.