title: Magnetic Nanoparticle-Based Platform for Characterization of Shiga-like Toxin 1 from Complex Samples.
abstract: Foodborne illness outbreaks resulting from contamination of Escherichia coli O157:H7 remain a serious concern in food safety. E. coli O157:H7 can cause bloody diarrhea, hemolytic uremic syndrome, or even death. The pathogenicity of E. coli O157:H7 is mainly caused by the expression of Shiga-like toxins (SLTs), i.e., SLT-1 and SLT-2. SLTs are pentamers composed of a single A and five B subunits. In this study, we propose a magnetic nanoparticle (MNP)-based platform to rapidly identify SLT-1 from the complex cell lysate of E. coli O157:H7. The core of the MNPs is made of iron oxide, whereas the surface of the core is coated with a thin layer of alumina (Fe3O4@Al2O3 MNPs). The Fe3O4@Al2O3 MNPs are functionalized with pigeon ovalbumin (POA), which contains Gal-α(1→4)-Gal-β(1→4)-GlcNAc termini that can bind SLT-1B selectively. Furthermore, POA is a phosphate protein. Thus, it can be easily immobilized on the surface of the Fe3O4@Al2O3 MNPs through aluminum phosphate chelation under microwave heating within 1.5 min. The generated POA-Fe3O4@Al2O3 MNPs are capable of effectively enriching SLT-1B from complex cell lysates simply by pipetting 20 μL of the sample in and out of the tip in a vial for ∼1 min. To release SLT-1 from the MNPs, Gal-α(1→4)-Gal disaccharides were used for displacement. The released target species are sufficient to be identified by matrix-assisted laser desorption/ionization mass spectrometry. Although the sample volume used in this approach is small (20 μL) and the enrichment time is short (1 min), the selectivity of this approach toward SLT-1B is quite good. We have demonstrated the effectiveness of this approach for rapid determination of the presence of SLT-1 from complex cell lysates and ham/juice samples based on the detection of SLT-1B.
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University , Hsinchu 300, Taiwan.
authors.forename: Fang-Yin
authors.initials: FY
authors.lastname: Kuo
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University , Hsinchu 300, Taiwan.
authors.forename: Bo-Yao
authors.initials: BY
authors.lastname: Chang
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University , Hsinchu 300, Taiwan.
authors.forename: Ching-Yi
authors.initials: CY
authors.lastname: Wu
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University , Hsinchu 300, Taiwan.
authors.forename: Kwok-Kong Tony
authors.initials: KK
authors.lastname: Mong
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University , Hsinchu 300, Taiwan.
authors.forename: Yu-Chie
authors.initials: YC
authors.lastname: Chen
mesh_terms: D019453:Escherichia coli O157 / Q000737:chemistry* / Q000166:cytology; D005506:Food Contamination / Q000032:analysis*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D022622:Shiga Toxin 1 / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D058185:Magnetite Nanoparticles; D022622:Shiga Toxin 1