A sensitive sensing system based on fluorescence dipeptide nanoparticles for sulfadimethoxine determination

Abstract

Various types of fluorescent nanoparticles have been proposed for the detection of veterinary drug residues in food. However, structure-induced fluorescence nanoparticles with biodegradability and the capacity to conjugate with molecular recognition elements are lacking. Here, a biodegradable tryptophan-phenylalanine dipeptide-based nanomaterial was assembled and modified with a sulfadimethoxine aptamer (TPNPs@aptamer). Then, a novel and efficient fluorescence sensing strategy, based on TPNPs@aptamer and BHQ1-labeled single-stranded DNA (BHQ1@cDNA), was developed for sulfadimethoxine determination. Under optimal conditions, the fluorescence was linear in the range of 0–200 ng/mL sulfadimethoxine with a detection limit of 1.47 ng/mL (S/N = 3). Satisfactory recoveries of standard additions were found between 92.88 % and 114.15 % for water and milk samples with a relative standard deviation less than 5.0 %, suggesting that the proposed fluorescence sensing strategy can be applied reliably in sulfadimethoxine analysis of liquid foods.