Phage/aptamer dual-encoded hydrogel arrays integrated with microfluidic platforms for simultaneous detection of multiple food pathogens

Food pathogens pose significant threats to public health. This study presents a universal, sensitive and time-efficient microfluidic chip electrophoresis (MCE) platform for simultaneously detecting multiple food pathogens based on phage/aptamer dual-encoded hydrogel arrays. The arrays are comprised of "all-in-one" hydrogel slices embedded with the capturing probe of specific phages and sensing probe of ATP aptamer/complementary chain (A-Apt/cDNA) hybrid structures. The live bacteria are specifically captured and lysed by the corresponding phages to generate copious amounts of ATP. The ATP further combines with the A-Apt/cDNA hybrids to release the cDNA strands with various lengths from the hydrogel pores into the supernatant. Therefore, cDNA strands whose lengths are specific for each bacteria function as markers for ATP, the level of which represents the number of living bacteria. The qualitation and quantification of multiple bacteria is realized by isolating and analyzing various cDNA using MCE. Taking three food pathogens (i.e., E. coli, Salmonella typhimurium, Staphylococcus aureus) as target models, the platform were performed within 60 min, with detection limits of 20 CFU/mL, 30 CFU/mL and 15 CFU/mL, respectively. This study offers a universal and rapid strategy for multiple food pathogens analysis.