A label-free fluorescence sensing strategy based on gold nanoparticles assisted copper nanoclusters for the detection of aflatoxin B1 in cereals and peanuts

To effectively monitor the degree of aflatoxin B1 (AFB1) contamination in food and mitigate potential health risks to consumers eating food contaminated with AFB1, a label-free fluorescence aptamer-sensing strategy utilizing gold nanoparticles (AuNPs) was developed. Polyvinylpyrrolidone-copper nanoclusters (PVP-CuNCs) and AuNPs were selected as donor/acceptor pairs to convert the color signal change of AuNPs into fluorescence signal changes in PVP-CuNCs via the inner filter effect (IFE). In the presence of AFB1, the aptamer preferentially adsorbed with AFB1, and the AuNPs without aptamer protection changed color from red to blue under NaClinduced aggregation. The green fluorescence of PVP-CuNCs recovered gradually. The developed strategy offers high sensitivity for the detection of AFB1, with a linear range of 0.02-20 mu g L-1, and a low detection limit of 0.69 mu g L- 1. In addition, the strategy was successfully applied to real samples such as corn, rice, oats and peanuts, and the recovery rate was 93.4-106.2 %, which verified the reliability and applicability of this strategy. This strategy has the advantages of cost-effectiveness, high sensitivity, low detection limit and easy operation, providing a reference for sensitive and selective detection of mycotoxins contamination in food.