title: Antibody-integrated and functionalized graphite-encapsulated magnetic beads, produced using ammonia gas plasma technology, for capturing Salmonella.
abstract: Salmonella spp. is the single and most important causative agent of foodborne infections, especially involving foods such as eggs, milk and meat. To prevent infection, a reliable surveillance system is required that can quickly and sensitively detect Salmonella. Here, we describe the development of antibody-integrated magnetic beads that are functionalized by a novel strategy using ammonia gas plasma. Ammonia plasma, produced by a radio frequency (RF) power supply, was allowed to react with the surface of graphite-encapsulated magnetic beads, resulting in the introduction of amino groups. An anti-Salmonella antibody was then anchored by sulfide groups present on the protein surface to the amino groups of the magnetic beads via N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP). The potential usefulness of these magnetic beads for capturing Salmonella was examined as follows. The beads were incubated with Salmonella in liquid medium and then separated from the supernatant by applying a magnetic field. After thorough washing, adsorption of Salmonella to the beads was confirmed by immunochromatography, polymerase chain reaction and a direct culture assay. Our findings indicate that the capture and concentration of Salmonella using the antibody-integrated magnetic beads was more efficient than commercial Dynabeads® anti-Salmonella, which are conventionally used for concentrating Salmonella from liquid cultures. We believe this novel bead technology will contribute to the enhanced detection of Salmonella.
authors: Laboratory of Biometabolic Chemistry, School of Health Sciences, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan. Electronic address: sakudo@med.u-ryukyu.ac.jp.
authors: Akikazu
authors: A
authors: Sakudo
authors: Graduate School of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8011, Japan.
authors: Han
authors: H
authors: Chou
authors: Graduate School of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8011, Japan; Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8011, Japan.
authors: Masaaki
authors: M
authors: Nagatsu
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D055910:Antibodies, Immobilized / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods*; D058626:Plasma Gases / Q000737:chemistry*; D012475:Salmonella / Q000302:isolation & purification*; D012480:Salmonella Infections / Q000175:diagnosis / Q000382:microbiology*
chemical_list: D055910:Antibodies, Immobilized; D058626:Plasma Gases; D000641:Ammonia; D006108:Graphite
keywords: Amino group; Capture; Gas plasma; Magnetic beads; Salmonella