A nanomaterial-free and thionine labeling-based lateral flow immunoassay for rapid and visual detection of the transgenic CP4-EPSPS protein

"Blue-red-purple" multicolored lateral flow immunoassay for simultaneous detection of GM crops utilizing RPA and CRISPR/Cas12a

Advanced multiplexed testing techniques should be designed and developed to ensure an accurate and reliable evaluation for unknown samples. In this study, an efficient platform coupled with the "Blue-Red-Purple" strategy based on recombinant polymerase amplification (RPA), CRISPR/Cas12a and lateral flow strip was established, which could realize the dual-target detection of CP4-EPSPS and Cry1Ab/Ac in genetically modified crops. The lateral flow immunoassay was developed using different colored microspheres to label the antibodies to realize the visualization of results and avoid cross-reactions. The proposed method exhibits high specificity, sensitivity and stability. The visual detection limits of standard plasmids and real samples reached 10 copies/μL and 0.5 %, respectively, which could be stored at 4 °C for 12 months with high detection ability. Moreover, the entire detection process could be completed within 50 min without any complex instruments or professional operators. These findings indicated that a sensitive, specific, rapid and accurate method was established for on-site detection of GM crops.

Multi-chromatic and multi-component lateral flow immunoassay for simultaneous detection of CP4 EPSPS, Bt-Cry1Ab, Bt-Cry1Ac, and PAT/bar proteins in genetically modified crops

A multi-chromatic and multi-component lateral flow immunoassay (MCMC-LFIA) was developed for simultaneous detection of CP4 EPSPS, Bt-Cry1Ab, Bt-Cry1Ac, and PAT/bar proteins in genetically modified (GM) crops. Captured antibodies specific to these exogenous proteins were separately immobilized on a nitrocellulose membrane as test zones. Multi-colored microspheres, used as visible multi-probes, were conjugated with corresponding antibodies and sprayed on the conjugate pad. The assay results can be visually interpreted within 10 min by observing the appearance of colored bands. The MCMC-LFIA demonstrated high sensitivity, with detection of limits of 7.8 ng/mL for CP4 EPSPS and 2.5 ng/mL for Bt-Cry1Ab, Bt-Cry1Ac, and PAT/bar proteins, significantly improving the performance of previously reported LFIAs. The MCMC-LFIA exhibited excellent specificity and was validated for practical use in field-based applications. The proposed MCMC-LFIA offers a rapid, sensitive, and user-friendly tool for the on-site large-scale screening of GM materials.