A highly sensitive competitive aptasensor for AFB 1 detection based on an exonuclease-assisted target recycling amplification strategy.

Aflatoxin B (AFB) is a typical mycotoxin found in agricultural products, and poses a huge threat to both humans and animals. Accurate and rapid measurement of AFB is essential for environmental analysis and food safety. Based on molecular docking simulation design and exonuclease-assisted target recycling amplification, we designed a competitive fluorescence aptasensor to detect AFB rapidly and sensitively. According to the molecular docking simulations, a complementary strand (cDNA) was designed by searching for potential binding sites of the aptamer, which had the lowest binding energy. Magnetic beads modified with biotin-Apt were used as the capture probe, while FAM-labeled cDNA acted as the reporter probe. By using EXO I for target recycling amplification, this aptasensor was highly sensitive and selective for AFB. The detection limit of the suggested aptasensor under optimal conditions was 0.36 ng mL (S/N = 3) in the range of 1-1000 ng mL ( = 0.991). The developed aptasensor was successfully used to analyze AFB in oil samples.