A novel fluorescence biosensor based on CRISPR/Cas12a integrated MXenes for detecting Aflatoxin B1

Aflatoxin B1 (AFB1) contamination in food threatens global food safety, and rapid quantitative detection of AFB1 remains a challenge. Herein, a novel fluorescence biosensor was developed for AFB1 detection based on CRISPR/Cas12a and MXenes. Specifically, the well-designed activator was locked by dual-AFB1 aptamers, Cas12a was directly linked to crRNA to form inactivated complexes, and MXenes efficiently adsorbed FAM fluorophore-modified single-stranded DNA (ssDNA-FAM), quenching its fluorescence. In the presence of AFB1, the activator was released due to the preferential binding of the aptamer to AFB1, and the released activator then activated the trans-cleavage activity of Cas12a to indiscriminately cleave ssDNA on MXenes, leading to the recovery of the fluorescence signal. The fluorescent biosensor had a wide detection range from 0.001 to 80 ng mL^-1, a detection limit of 0.92 pg mL^-1, and the ability to detect within 80 min. More importantly, the platform demonstrates excellent detection performance in real peanut samples.