The development of RPA and CRISPR-Cas12a based immunoassay strip for sensitive detection of genetically modified crops

Rapid detection method with high sensitivity has been expected in transgenic field screening. In this study, an ultra-sensitive visualization detection procedure based on recombinase polymerase amplification, CRISPR/Cas12a system, and lateral flow strip technology (RPA-Cas12a-LFB) was developed for the rapid detection of genetically modified (GM) crops. P-CaMV 35 S and T-NOS screening elements, the most widely covered in GM crops, were targeted. The results showed that standard plasmids as low as 10 copies and 0.01% GM crops of Bt11 and MON863 samples can be detected, demonstrating the ultra-sensitivity of the method. The assay was applied to a series of GM crop standards, and the results were consistent with those of existing methods, exhibiting the excellent specificity and feasibility. The analysis can be completed within 40 min, realizing rapid detection. Overall, an accurate, sensitive, time-saving, and instrument-independent detection system was successfully developed, providing a new strategy with ultra-sensitive capability in detection.