(157ai) Foodborne Pathogen Detection: Identification of Protein Catalyzed Capture Agents Targeting E. coli O157:H7

The World Health Organization estimates 582 million illnesses occur annually due to foodborne pathogen infections. Culture based detection methods are considered the “gold-standard” for identifying pathogen contamination, but are laborious to perform and fail to detect contamination in real-time. While antibody based sensors exhibit excellent affinity and specificity their costs, cold-chain storage requirements, and batch-to–batch variation limit their widespread use (especially in developing regions). Peptides represent ideal antibody alternatives exhibiting improved storage and shelf-life, cost-effective and reproducible chemical synthesis, and the ability to incorporated unique unnatural chemistries. This research seeks to discover novel peptide recognition elements (PCCs) targeting E. coli O157:H7 by the Protein Catalyzed Capture method, for applications in detecting contamination in food samples. Here, a peptide based One Bead One Compound (OBOC) library is screened against synthetic peptide epitopes (SynEps) unique to E. coli O157:H7. Peptide recognition elements exhibiting nM affinity are identified by an in situ un-catalyzed “click” reaction resulting from entropically favorable interactions between a SynEp and library bead. Edman degradation enables sequencing of the library peptide responsible for target binding. Individual PCC affinity is then assessed quantitatively by multiplex immunoassay. Magnetic beads are then modified with lead PCCs and employed to separate E. coli from complex samples. Ultimately, promising PCC agents will be incorporated into various sensing platforms (such as electrochemical (EIS), visual (lateral flow), or optical (SPR)) to enable wide-spread food pathogen detection.