Visual and self-contained diagnosis of Salmonella using RPA-CRISPR on a centrifugal force driven microfluidic system

Rapid and sensitive nucleic acid detection is very important for the detection of Salmonella in food. Convenient detection methods show great potential in food safety. CRISPR-Cas12a system has been widely used for nucleic acid detection. In one-pot reaction, Cas12a can perform cis- and trans-cleavage of amplicons and primers, which reduces the sensitivity of the reaction and has certain limitations. In this study, we integrated the Cas12a cutting system with recombinase polymerase amplification (RPA) into one microfluidic chip to avoid cap opening pollution. A portable observation device was integrated to enable visual detection of signals with the naked eye. The detection technology could specifically detect 1 × 10° CFU/mL Salmonella in 50 min at 37 °C. In the field test, there was no need for professional equipment or high-tech means.