A CG@MXene nanocomposite-driven E-CRISPR biosensor for the rapid and sensitive detection of Salmonella Typhimurium in food.

In this study, we developed a novel electrochemical biosensor based on CRISPR/Cas12a (E-CRISPR) for the rapid and sensitive detection of Salmonella Typhimurium (S. Typhimurium). The CRISPR/Cas12a system was applied to identify S. Typhimurium gene and induce signal changes in electrochemical measurement. The colloidal gold and MXene (CG@MXene) nanocomposites were synthesized and immobilized to improve the performance of the biosensor by decreasing the background noise. The formation process of CG@MXene was well characterized, and experiment conditions were fully optimized. Under the optimal conditions, the proposed E-CRISPR biosensor exhibited excellent sensitivity for S. Typhimurium, with a limit of detection (LOD) of 160 CFU/mL, and great specificity against other common foodborne pathogens. Furthermore, the feasibility of the E-CRISPR biosensor was evaluated by analyzing S. Typhimurium-spiked chicken samples, with a recovery rate ranging from 100.46% to 106.37%. In summary, this research proposed a novel E-CRISPR biosensor from a new perspective to detect S. Typhimurium which can be an alternative approach for bacterial detection in the food supply chain.