Dual-mode CRISPR/Cas12a-assisted fluorescent and lateral flow aptasensor based on a newly truncated aptamer for Fumonisin B1 detection.

As a Group 2B carcinogen, accurate and efficient detection for Fumonisin B1 (FB1) is essential. The emergence of aptamers presents a viable solution to meet this demand. In this study, a truncated aptamer named Apt40 was developed, showcasing remarkable binding affinity to FB1. In recent years, the role of Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) and CRISPR-associated 12a protein (Cas12a) in detection became increasingly significant, especially utilizing the trans-cleavage of Cas12a/CRISPR RNA (crRNA) complex. To further evaluate the applicability of the Apt40, a dual-mode CRISPR/Cas12a-assisted fluorescent and lateral flow aptasensor was constructed. Notably, the crRNA was designed to complementarily bind with Apt40 in its active binding sites, thus activating the trans-cleavage of Cas12a/crRNA to signal probes. Consequently, the fluorescent aptasensor exhibited a linear range of 10-1500 ng/mL with a Limit of Detection (LOD) of 0.802 ng/mL, while the lateral flow aptasensor showed a 200-3000 ng/mL linear range with a 9.031 ng/mL LOD. Both aptasensors provided high recoveries (95.11 %-106.63 %) in corn oil and starch samples, underscoring their precisions. We anticipate that this systematic strategy, from optimizing aptamer's performance to developing a novel dual-mode aptasensor, can provide a universal framework and valuable insights for the detection of other target molecules.