Sensitive detection of patulin based on DNase Ⅰ-assisted fluorescent aptasensor by using AuNCs-modified truncated aptamer

Patulin (PAT) is a mycotoxin that exists in a wide range and is harmful to human health, which has aroused great attention to food safety. In this study, we established a novel assay to detect food samples contaminated by PAT. First of all, we proposed a truncation protocol based on the secondary structure of aptamer. By removing the stem-loop structure one by one, an optimized truncated PAT aptamer (P-30) was obtained. To the best of our knowledge, the mechanism between PAT and P-30 was elaborated in the assisting of molecular docking and circular dichroism for the first time. Furthermore, we developed a sensitive aptasensor platform to detect PAT in food samples. The aptamer modified with gold nanoclusters (AuNCs) was used as fluorescent probe, and BSA-directed synthesized MnO2 nanoflakes (MnO2 NFs) as fluorescence receptor. Additionally, fluorescence signal amplification strategy assisted by DNase Ⅰ successfully improved the sensitivity of aptasensor. The developed assay had a low detection limit of 8.5 ng/L, and can be effectively used in apple and grape juice samples. Thus, the established aptasensor shows a broad application prospect in PAT detection.