A smart microfluidic platform for rapid multiplexed detection of foodborne pathogens

Rapid and sensitive detection of foodborne pathogens in food industry is of high importance in day-to-day practice to ensure safe food. To address this issue, multiple foodborne pathogens are targeted for rapid identification based in DNA amplification. A 3D PDMS sponge was fabricated using salt crystals as scarifying mold and functionalized with a ligand, apolipoprotein-H (ApoH), to test bacterial capturing for both Gram positive (L. monocytogenes) and negative bacteria (Salmonella spp.), in a microfluidic device. Pure culture of both pathogens in a range of similar to 10-10(5) CFU/mL were tested and the application of the developed automated pre-concentration protocol in real samples was verified using spiked surface samples after swab sampling. Bacterial DNA was extracted directly from the sponge and used for Real Time quantitative Polymerase Chain Reaction (qPCR) detection. The sponges did not show any significant resistance to sample flow and could easily be incorporated in a microfluidic device. A capture efficiency above 70% was observed for both targeted (Gram positive and Gram negative) pathogens and a Limit of Detection (LoD) in the range of 10(3) and 10(4) CFU/mL was obtained for Salmonella spp. and L. monocytogenes, respectively. Using this approached, we are able to perform multiplexed (Gram positive and Gram negative) capturing and reduce the enrichment time compared to the gold standard plate culture (over 1-day) method. The use of a 3D sponge for direct capturing of multiplexed pathogen on microfluidic device, followed by qPCR detection is an efficient and versatile method to stratify the presence of bacteria. This approach and methodology has potential to be integrated in full automatized device and used as point of need (PoN) system for foodborne pathogen stratification in food packaging/production industries.