Portable DNA extraction integrated with LAMP-CRISPR/Cas12a technology for on-site detection of Salmonella Typhimurium.

The infection and outbreak of Salmonella typhimurium (S. typhimurium) highlight the need for developing a reliable on-site detection strategy fitting to various settings. However, due to the requirement of specialized instruments and trained personnel, traditional detection methods have to be implemented in laboratories and are not ideal for on-site applications. To achieve a sample-to-answer and field-deployable detection for S. typhimurium, we developed an integrated nucleic acid detection platform combining single-vial of loop-mediated isothermal amplification (LAMP)-clustered regularly interspaced short palindromic repeat (CRISPR)/Cas12a system, portable device and smartphone app. This platform enables the extraction, concentration, and purification of DNA, amplification of the target, and output of visual fluorescent signals within 1 h. With this detection platform, 102 CFU/mL of S. typhimurium in food and environmental matrix was able to be accurately detected. This method demonstrated excellent selectivity. Also, an auxiliary smartphone application was developed to achieve simplified result interpretation. Our method exhibited potential to better control and respond to outbreaks of foodborne diseases, especially in low-resource settings.