A fluorescent cascade amplification method for sensitive detection of Salmonella based on magnetic Fe3O4 nanoparticles and hybridization chain reaction

In this study, a pair of specific primers based on invA of Salmonella was designed and used in asymmetric polymerase chain reaction (aPCR) to produce a long target single-stranded DNA (ssDNA) that was captured by biotin-probe labeled magnetic beads (MBs) forming the MBs-ssDNA. The target ssDNA triggered HCR amplification with the two carboxyfluorescein (FAM) labeled DNA hairpin reporter probes (H1-FAM, H2-FAM) that enabled the measurements of the fluorescence intensities from the resulting ssDNA∼(H1-FAM ∼H2-FAM)n. The Fe3O4 nanoparticles were used to isolate the target ssDNA which hybridized with the reporter probes and led to decreased background signal that resulted in a detection limit of 7.4 × 101 CFU/mL in buffer and 6.9 × 102 CFU/g in spiked lettuce. The method developed also showed excellent selectivity over several common foodborne pathogens. The Fe3O4 nanoparticles capture coupled with fluorescence detection sensor showed promise for the detection of Salmonella.
Source: Sensors and Actuators B: Chemical - Category: Chemistry Source Type: research