CRISPR/Cas12a-mediated marker-free fluorescent biosensing platform based on a lightful copper nanocluster for highly...

The problem of mycotoxin contamination in foodstuffs has attracted widespread attention and posed a great threat to human health. Therefore, the sensitive and effective detection of mycotoxins is of great importance for preserving public health worldwide. In this study, a CRISPR/Cas12a-mediated marker-free fluorescent biosensing platform was constructed for highly sensitive and fast detection of aflatoxin B1. The copper nanoclusters were synthesized with marker-free DNA single strands within 5 min, showing the outstanding fluorescence properties. With the existence of aflatoxin B1, the released complementary DNA (cDNA) triggered multiple isothermal amplification reaction. Subsequently, the obtained amplification products triggered the trans-cleavage activity of CRISPR/Cas12a system, which degraded the DNA single strands for synthesis of copper nanoclusters, leading to a decreased fluorescent signal. Benefiting from good fluorescence properties of copper nanoclusters, the established biosensing platform for aflatoxin B1 detection had a high specificity and a limit of detection of 47.51 pg/mL in the linear range of 0.05-10 ng/mL. The proposed platform provided a new insight for the detection of non-nucleic acid targets.