Production and evaluation of the utility of novel phage display-derived peptide ligands to Salmonella spp. for magnetic separation

Aims: The objectives of this study were to produce Salmonella-specific peptideligands by phage display biopanning and evaluate their use for magneticseparation (MS).
Methods and Results: Four-phage display biopanning rounds were performed,and the peptides expressed by the two most Salmonella-specific (on the basisof phage-binding ELISA results) phage clones, MSal020401 and MSal020417,were chemically synthesized and coupled to MyOneTMtosylactivatedDynabeadsâ. Peptide capture capability for whole Salmonella cells fromnonenriched broth cultures was quantified by MS + plate counts andMS + GreenlightTMdetection and compared to capture capability of anti-Salmonella (antibody-coated) Dynabeadsâ.MS+ GreenlightTMgave a morecomprehensive picture of capture capability than MS + plate counts andshowed that Peptide MSal020417-coated beads exhibited at least similar, if notbetter, capture capability to anti-Salmonella Dynabeadsâ(mean capture valuesof 360  182 and 312  201%, respectively, over Salmonella spp.concentration range 3 9 101–3 9 106CFU ml1) with cross-reactivity of 19% to three other foodborne pathogens: Escherichia coli, Listeriamonocytogenes and Campylobacter jejuni.
Conclusions: One of the phage display-derived peptide ligands wasdemonstrated by MS + GreenlightTMto be a viable antibody alternative for MSof Salmonella spp.
Significance and Impact of the Study: This study demonstrates an antibody-free approach to Salmonella detection and opens substantial possibilities formore rapid tests for this bacterium.