title: Silicon Nitride Bioceramics Induce Chemically Driven Lysis in Porphyromonas gingivalis.
abstract: Organisms of Gram-negative phylum bacteroidetes, Porphyromonas gingivalis, underwent lysis on polished surfaces of silicon nitride (Si3N4) bioceramics. The antibacterial activity of Si3N4 was mainly the result of chemically driven principles. The lytic activity, although not osmotic in nature, was related to the peculiar pH-dependent surface chemistry of Si3N4. A buffering effect via the formation of ammonium ions (NH4(+)) (and their modifications) was experimentally observed by pH microscopy. Lysis was confirmed by conventional fluorescence spectroscopy, and the bacteria's metabolism was traced with the aid of in situ Raman microprobe spectroscopy. This latter technique revealed the formation of peroxynitrite within the bacterium itself. Degradation of the bacteria's nucleic acid, drastic reduction in phenilalanine, and reduction of lipid concentration were observed due to short-term exposure (6 days) to Si3N4. Altering the surface chemistry of Si3N4 by either chemical etching or thermal oxidation influenced peroxynitrite formation and affected bacteria metabolism in different ways. Exploiting the peculiar surface chemistry of Si3N4 bioceramics could be helpful in counteracting Porphyromonas gingivalis in an alkaline pH environment.
authors.affiliation: Ceramic Physics Laboratory, Kyoto Institute of Technology , Sakyo-ku, Matsugasaki, 606-8126 Kyoto, Japan.|Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pezzotti
authors.affiliation: Amedica Corporation, 1885 West 2100 South, Salt Lake City, Utah 84119, United States.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Bock
authors.affiliation: Amedica Corporation, 1885 West 2100 South, Salt Lake City, Utah 84119, United States.
authors.forename: Bryan J
authors.initials: BJ
authors.lastname: McEntire
authors.affiliation: Amedica Corporation, 1885 West 2100 South, Salt Lake City, Utah 84119, United States.
authors.forename: Erin
authors.initials: E
authors.lastname: Jones
authors.affiliation: Ceramic Physics Laboratory, Kyoto Institute of Technology , Sakyo-ku, Matsugasaki, 606-8126 Kyoto, Japan.|Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Marco
authors.initials: M
authors.lastname: Boffelli
authors.affiliation: Department of Medical Engineering for Treatment of Bone and Joint Disorders, Osaka University , 2-2 Yamadaoka, Suita, Osaka 565-0854, Japan.
authors.forename: Wenliang
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Ceramic Physics Laboratory, Kyoto Institute of Technology , Sakyo-ku, Matsugasaki, 606-8126 Kyoto, Japan.|Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Greta
authors.initials: G
authors.lastname: Baggio
authors.affiliation: Ceramic Physics Laboratory, Kyoto Institute of Technology , Sakyo-ku, Matsugasaki, 606-8126 Kyoto, Japan.|Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Francesco
authors.initials: F
authors.lastname: Boschetto
authors.affiliation: Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Puppulin
authors.affiliation: Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Adachi
authors.affiliation: Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Toshiro
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Narisato
authors.initials: N
authors.lastname: Kanamura
authors.affiliation: Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Marunaka
authors.affiliation: Amedica Corporation, 1885 West 2100 South, Salt Lake City, Utah 84119, United States.|Department of Orthopaedic Surgery, University of Missouri , Columbia, Missouri 65212, United States.
authors.forename: B Sonny
authors.initials: BS
authors.lastname: Bal
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000378:metabolism; D001433:Bacteriolysis; D002516:Ceramics; D004269:DNA, Bacterial / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D030421:Peroxynitrous Acid / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D016966:Porphyromonas gingivalis / Q000187:drug effects* / Q000378:metabolism; D012329:RNA, Bacterial / Q000378:metabolism; D017655:Silicon Compounds / Q000737:chemistry / Q000494:pharmacology*; D012822:Silicon Dioxide
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D010743:Phospholipids; D012329:RNA, Bacterial; D017655:Silicon Compounds; D030421:Peroxynitrous Acid; D012822:Silicon Dioxide; D000641:Ammonia; C032734:silicon nitride