Polyethersulfone-Based Microfluidic Device Integrated with DNA Extraction on Paper and Recombinase Polymerase Amplification for the Detection of Salmonella enterica

Rising consumption, large-scale production, and widespread distribution have been accompanied by an increase in the number of Salmonella infections reported to implicate contaminated food products. We developed a portable origami microfluidic device that enabled rapid detection of S. enterica from sample preparation to end-point detection, including nucleic acid extraction on paper dipstick without pipetting, nucleic acid amplification using isothermal recombinase polymerase amplification (RPA), and lateral flow assay for results readout. We also explored the feasibility of the polyethersulfone (PES) membrane as a new reaction matrix against the widely used chromatography paper to optimize nucleic acid amplification. Nucleic acid amplification was achieved within 20 min and demonstrated 100% specificity to S. enterica. The limit of detection of this PES-based microfluidic device was 260 CFU/mL and equivalent to RPA reaction in tube. A chromatography paper-based microfluidic device was found 1-log less in sensitivity for Salmonella detection compared to the use of PES. This PES-based microfluidic device could detect S. enterica in lettuce, chicken breast, and milk at concentrations of 6 CFU/g, 9 CFU/g, and 58 CFU/mL, respectively, after 6 h enrichment. PES has shown high compatibility to isothermal nucleic acid amplification and great potential to be implemented as an integrated sample-to-answer microfluidic device for the detection of pathogens in various food commodities.