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Sulfadiazine (SDZ) residues in food products and the environment pose a serious threat to human health and ecological balance, thereby warranting the development of new methods for simple, rapid and...

Herein, we developed a novel truncation technique for aptamer sequences to fabricate highly sensitive aptasensors based on molecular docking and molecular dynamics simulations. The binding mechanism and energy composition of the aptamer/sulfaquinoxaline (SQX) complexes were investigated. We successfully obtained a new SQX-specific aptamer (SBA28-1: CCCTAGGGG) with high affinity (Kd = 27.36 nM) and high specificity determined using graphene oxide. This aptamer has a unique stem-loop structure that can bind to SQX. Then, we fabricated a fluorescence aptasensor based on SBA28-1, gold nanoparticles (AuNPs), and rhodamine B (RhoB) that presented a good linear range of 1.25–160 ng/mL and a limit of detection of 1.04 ng/mL. When used to analyze water samples, the aptasensor presented acceptable recovery rates of 93.1–100.1% and coefficients of variation (CVs) of 2.2–10.2%. In conclusion, the fluorescence aptasensor can accurately and sensitively detect SQX in water samples and has good application prospects.

A fluorescence aptasensor was developed based on two-dimensional nanomagnetic materials Fe3O4/Au/g-C3N4 and FAM-labeled aptamer of sulfamethazine (FAM-SMZ1S) for sensitive and rapid detection of sulfamethazine (SMZ) in animal-derived foods. The aptasensor exhibited a high sensitivity with the limit of detection (LOD) of 0.87 ng/mL (S/N = 3), the linear range from 1 ng/mL to 100 ng/mL. The performance of aptasensor was demonstrated in 10 real-world samples with the recovery rate in the range of 91.6%-106.82% and the coefficient of variation (CV) in the range of 2.8%-13.44%. In addition, the detection ability of the aptasensor was comparable with that of the HPLC as the detection results demonstrated good correlations (R2 > 0.9153). Therefore, the aptasensor can be a sensitive, accurate and rapid method for the detection of SMZ in animal-derived foods.