title: Effect of Polyethylene Glycol on the Formation of Magnetic Nanoparticles Synthesized by Magnetospirillum magnetotacticum MS-1.
abstract: Magnetotactic bacteria (MTB) synthesize intracellular magnetic nanocrystals called magnetosomes, which are composed of either magnetite (Fe3O4) or greigite (Fe3S4) and covered with lipid membranes. The production of magnetosomes is achieved by the biomineralization process with strict control over the formation of magnetosome membrane vesicles, uptake and transport of iron ions, and synthesis of mature crystals. These magnetosomes have high potential for both biotechnological and nanotechnological applications, but it is still extremely difficult to grow MTB and produce a large amount of magnetosomes under the conventional cultural conditions. Here, we investigate as a first attempt the effect of polyethylene glycol (PEG) added to the culture medium on the increase in the yield of magnetosomes formed in Magnetospirillum magnetotacticum MS-1. We find that the yield of the formation of magnetosomes can be increased up to approximately 130 % by adding PEG200 to the culture medium. We also measure the magnetization of the magnetosomes and find that the magnetosomes possess soft ferromagnetic characteristics and the saturation mass magnetization is increased by 7 %.
authors.affiliation: Bio-Nano Electronics Research Centre, Toyo University, Kawagoe, Saitama, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Shimoshige
authors.affiliation: Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Bio-Nano Electronics Research Centre, Toyo University, Kawagoe, Saitama, Japan; Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, Saitama, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Mizuki
authors.affiliation: Bio-Nano Electronics Research Centre, Toyo University, Kawagoe, Saitama, Japan; Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, Saitama, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nagaoka
authors.affiliation: Bio-Nano Electronics Research Centre, Toyo University, Kawagoe, Saitama, Japan; Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, Saitama, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Inoue
authors.affiliation: Bio-Nano Electronics Research Centre, Toyo University, Kawagoe, Saitama, Japan; Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, Saitama, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Maekawa
mesh_terms: D003470:Culture Media / Q000494:pharmacology; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D055944:Magnetosomes / Q000187:drug effects / Q000648:ultrastructure; D042201:Magnetospirillum / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000494:pharmacology*
chemical_list: D003470:Culture Media; D058185:Magnetite Nanoparticles; D011092:Polyethylene Glycols