Silicon Nitride Bioceramics Induce Chemically Driven Lysis in Porphyromonas gingivalis

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• 作者：Giuseppe Pezzotti ; Ryan M. Bock ; Bryan J. McEntire ; Erin Jones ; Marco Boffelli ; Wenliang Zhu ; Greta Baggio ; Francesco Boschetto ; Leonardo Puppulin ; Tetsuya Adachi ; Toshiro Yamamoto ; Narisato Kanamura ; Yoshinori Marunaka ; B. Sonny Bal
• 刊名：Langmuir
• 出版年：2016
• 出版时间：March 29, 2016
• 年：2016
• 卷：32
• 期：12
• 页码：3024-3035
• 全文大小：557K
• ISSN：1520-5827

文摘

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.