A magnetic-field-assisted fluorescence biosensing platform for rapid and sensitive detection of organophosphorus pesticides in food

Organophosphorus pesticides pose significant hazards to human health and can even cause fatalities, which necessitates the development of effective detection method. Herein, a magnetic-field-assisted fluorescence biosensing platform was designed for rapid and sensitive detection of organophosphorus pesticides. The underlying principle of this strategy was established upon complementary base pairing between aptamer-upconversion nanoparticles (UCNPs) and cDNA-Fe₃O₄@MoS₂. The stable stem-loop structures could provide the structural foundation enabling the aptamers to specifically recognize target pesticides. The formation of the UCNPs-aptamer-cDNA-Fe₃O₄@MoS₂ complex gradually decreased with increasing concentrations of target pesticides, leading to a reduction in fluorescence. Methyl parathion was successfully detected using this platform, achieving a detection limit of 0.002 ng/mL within a linear range of 0.01–100 ng/mL. The proposed method has also been validated in the medicinal and edible homologous foods with good recoveries. The platform could be expanded to detect other targets by using appropriate aptamers and cDNA, broadening its potential applications.