CRISPR-Cas12a-driven aptasensor for sensitive detection of alternariol by using a personal glucose meter.

Alternariol (AOH) has attracted much attention as an emerging toxin in edible herbs that can pose potential carcinogenic risks to human. However, the rapid detection of AOH to ensure food safety remains a challenge. Here, a CRISPR-Cas12a-mediated aptamer-based sensor (aptasensor) was proposed for the sensitive quantification of AOH by using a personal glucose meter. First, fluorescent probes were used to validate crRNA sequences that could activate Cas12a trans-cleavage activity. Owing to the high affinity of aptamer, different concentrations of AOH were able to release different levels of Cas12a cleavage activity to cut magnetic bead-modified invertase probes. The free invertase was collected to catalyze hydrolysis of sucrose to glucose. After optimizing a series of key parameters, the constructed aptasensor with dual signal amplification of Cas12a and invertase allowed for highly-sensitive AOH detection in a linear range of 0.45-3000 ng/mL with a detection limit of 0.048 ng/mL. In addition, this aptasensor was successfully applied in edible herb samples with satisfactory recovery rates of 92.19-102.40 %. This CRISPR-Cas12a-mediated aptasensing platform provides a simple and powerful alternative for rapid quantitative detection of AOH, which is of great significance for food safety.