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 widespreaddistributionhave been accompanied by an increase in the number of Salmonella infections reported to implicate contaminatedfood products. We developed a portable origami microfluidic devicethat enabled rapid detection of S. enterica from sample preparation to end-point detection, including nucleicacid extraction on paper dipstick without pipetting, nucleic acidamplification using isothermal recombinase polymerase amplification(RPA), and lateral flow assay for results readout. We also exploredthe feasibility of the polyethersulfone (PES) membrane as a new reactionmatrix against the widely used chromatography paper to optimize nucleicacid amplification. Nucleic acid amplification was achieved within20 min and demonstrated 100% specificity to S. enterica. The limit of detection of this PES-based microfluidic device was260 CFU/mL and equivalent to RPA reaction in tube. A chromatographypaper-based microfluidic device was found 1-log less in sensitivityfor Salmonella detection compared tothe use of PES. This PES-based microfluidic device could detect S. enterica in lettuce, chicken breast, and milkat concentrations of 6 CFU/g, 9 CFU/g, and 58 CFU/mL, respectively,after 6 h enrichment. PES has shown high compatibility to isothermalnucleic acid amplification and great potential to be implemented asan integrated sample-to-answer microfluidic device for the detectionof pathogens in various food commodities.

Automated summary

We developed a portable origami microfluidic device that can rapidly detect Salmonella-contaminated food. The device incorporates nucleic acid extraction, amplification, and detection on a paper dipstick. We optimized the amplification reaction using a polyethersulfone membrane, which showed high sensitivity and specificity to S. enterica. The device achieved nucleic acid amplification in 20 minutes with a detection limit of 260 CFU/mL.