title: Comparison of the antiviral effect of solid-state copper and silver compounds.
abstract: Antiviral activities of insoluble solid-state and soluble ionic copper and silver compounds were evaluated against influenza A virus (A/PR8/H1N1) possessing a viral envelope and bacteriophage Qβ lacking an envelope. The viral solutions were exposed on glass samples uniformly loaded with copper and silver compounds. Exposure to solid-state cuprous oxide (Cu2O) efficiently inactivated both influenza A virus and bacteriophage Qβ, whereas solid-state cupric oxide (CuO) and silver sulfide (Ag2S) showed little antiviral activity. Copper ions from copper chloride (CuCl2) had little effect on the activity of bacteriophage Qβ in spite of the fact that copper ions strongly inactivate influenza A in previous studies. Silver ions from silver nitrate (AgNO3) and silver(I) oxide (Ag2O) in solution showed strong inactivation of influenza A and weak inactivation of bacteriophage Qβ. We also investigated the influence of the compounds on the function of two influenza viral proteins, hemagglutinin and neuraminidase. Silver ions from AgNO3 and Ag2O remarkably decreased enzymatic activity of neuraminidase through the breakage of disulfide (SS) bonds, corresponding to the selective inactivation of influenza A virus. By contrast, exposure to Cu2O markedly reduced the activity of hemagglutinin rather than neuraminidase. These findings suggest that solid-state Cu2O disrupts host cell recognition by denaturing protein structures on viral surfaces, leading to the inactivation of viruses regardless of the presence of a viral envelope.
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-8656, Japan; Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Minoshima
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-8656, Japan.
authors.forename: Yue
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-8656, Japan.
authors.forename: Takuto
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Photocatalyst Group, Kanagawa Academy of Science and Technology, 3-25-13 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan; Department of Microbiology and Infectious Diseases, Nara Medical University, 840 Shijo-cho, Kashihara-shi, Nara 634-8521, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Nakano
authors.affiliation: Photocatalyst Group, Kanagawa Academy of Science and Technology, 3-25-13 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ishiguro
authors.affiliation: Photocatalyst Group, Kanagawa Academy of Science and Technology, 3-25-13 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan; Department of Urology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Kubota
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-8656, Japan; Research Institute of Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-Ku, Tokyo 153-8904, Japan. Electronic address: hashimoto@light.t.u-tokyo.ac.jp.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Hashimoto
authors.affiliation: Photocatalyst Group, Kanagawa Academy of Science and Technology, 3-25-13 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan; Research Institute of Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-Ku, Tokyo 153-8904, Japan. Electronic address: pg-sunada@newkast.or.jp.
authors.forename: Kayano
authors.initials: K
authors.lastname: Sunada
mesh_terms: D017908:Allolevivirus / Q000187:drug effects*; D000998:Antiviral Agents / Q000494:pharmacology*; D003300:Copper / Q000494:pharmacology*; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects*; D012834:Silver / Q000494:pharmacology*
chemical_list: D000998:Antiviral Agents; D012834:Silver; D003300:Copper
keywords: Antiviral; Hemagglutinin; Neuraminidase; Protein denaturation; Solid-state copper and silver compounds