Prussian blue nanoparticles-based signal amplification in aptamer-based lateral flow assay for procymidone detection

Procymidone is frequently detected in vegetables, prompting stringent regulatory limits in many countries and regions. Despite this, the development of rapid and sensitive detection methods remains limited. In this study, an aptamer-based lateral flow assay (LFA) was developed for procymidone detection, utilizing Prussian blue nanoparticles (PBNPs) as amplified signal markers, chosen for their intrinsic color and enzyme-like properties. An aptamer was coupled with the PBNPs to form a signal probe, enabling the construction of a competitive LFA. Under optimized conditions, the LFA achieved a limit of detection (LOD) of 0.35 ng/mL and a visual limit of detection (vLOD) of 0.64 ng/mL. The enzyme-mimetic activity of PBNPs was harnessed and such a catalytic reaction strategy further improved the assay sensitivity, leading to a further improvement of the LOD by 14.3-fold. The assay demonstrated high sensitivity, selectivity, and reproducibility, performing effectively in typical vegetable samples. This study provides a rapid, sensitive and reliable tool for procymidone detection, offering valuable insights and a new strategy for monitoring pesticides.