title: Development of antimicrobial biomaterials produced from chitin-nanofiber sheet/silver nanoparticle composites.
abstract: BACKGROUND
  Chitin nanofibers sheets (CNFSs) with nanoscale fiber-like surface structures are nontoxic and biodegradable biomaterials with large surface-to-mass ratio. CNFSs are widely applied as biomedical materials such as a functional wound dressing. This study aimed to develop antimicrobial biomaterials made up of CNFS-immobilized silver nanoparticles (CNFS/Ag NPs).
  
  
  METHODS
  CNFSs were immersed in suspensions of Ag NPs (5.17 ± 1.9 nm in diameter; mean ± SD) for 30 min at room temperature to produce CNFS/Ag NPs. CNFS/Ag NPs were characterized by transmission electron microscopy (TEM) and then tested for antimicrobial activities against Escherichia (E.) coli, Pseudomonas (P.) aeruginosa, and H1N1 influenza A virus, three pathogens that represent the most widespread infectious bacteria and viruses. Ultrathin sectioning of bacterial cells also was carried out to observe the bactericidal mechanism of Ag NPs.
  
  
  RESULTS
  The TEM images indicated that the Ag NPs are dispersed and tightly adsorbed onto CNFSs. Although CNFSs alone have only weak antimicrobial activity, CNFS/Ag NPs showed much stronger antimicrobial properties against E. coli, P. aeruginosa, and influenza A virus, with the amount of immobilized Ag NPs onto CNFSs.
  
  
  CONCLUSIONS
  Our results suggest that CNFS/Ag NPs interacting with those microbes exhibit stronger antimicrobial activities, and that it is possible to apply CNFS/Ag NPs as anti-virus sheets as well as anti-infectious wound dressings.
authors.affiliation: Faculty of System Design, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino, Tokyo, 191-0065, Japan. imvinhs@yahoo.com.vn.|Research Institute, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-1324, Japan. imvinhs@yahoo.com.vn.
authors.forename: Vinh Quang
authors.initials: VQ
authors.lastname: Nguyen
authors.affiliation: Research Institute, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-1324, Japan. ishihara@ndmc.ac.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ishihara
authors.affiliation: Department of Oral and Maxillofacial Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan. drom636@ndmc.ac.jp.
authors.forename: Jun
authors.initials: J
authors.lastname: Kinoda
authors.affiliation: Research Institute, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-1324, Japan. h2@ndmc.ac.jp.
authors.forename: Hidemi
authors.initials: H
authors.lastname: Hattori
authors.affiliation: Research Institute, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-1324, Japan. snaka@ndmc.ac.jp.
authors.forename: Shingo
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan. tono@ndmc.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ono
authors.affiliation: Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan. miyahira@ndmc.ac.jp.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyahira
authors.affiliation: Faculty of System Design, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino, Tokyo, 191-0065, Japan. tmatsui@sd.tmu.ac.jp.
authors.forename: Takemi
authors.initials: T
authors.lastname: Matsui
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology*; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology; D001672:Biocompatible Materials; D002686:Chitin / Q000737:chemistry*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004926:Escherichia coli / Q000187:drug effects / Q000648:ultrastructure; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects; D046529:Microscopy, Electron, Transmission; D057139:Nanofibers / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000648:ultrastructure; D012834:Silver / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D000998:Antiviral Agents; D001672:Biocompatible Materials; D002686:Chitin; D012834:Silver