title: Simple observation ofStreptococcus mutansbiofilm by scanning electron microscopy using ionic liquids.
abstract: Scanning electron microscopy (SEM) has been successfully used to image biofilms because of its high resolution and magnification. However, conventional SEM requires dehydration and metal coating of biological samples before observation, and because biofilms consist mainly of water, sample dehydration may influence the biofilm structure. When coated with an ionic liquid, which is a kind of salt that exists in the liquid state at room temperature, biological samples for SEM observation do not require dehydration or metal coating because ionic liquids do not evaporate under vacuum conditions and are electrically conductive. This study investigates the ability of ionic liquids to allow SEM observation ofStreptococcus mutansbiofilms compared with conventional coating methods. Two hydrophilic and two hydrophobic ionic liquids, all of which are electronic conductors, are used. Compared with samples prepared by the conventional method, the ionic-liquid-treated samples do not exhibit a fibrous extracellular matrix structure and cracking on the biofilm surface. The hydrophilic ionic liquids give clearer images of the biofilm structure than those of the hydrophobic ionic liquids. This study finds that ionic liquids are useful for allowing the observation of biofilms by SEM without preparation by dehydration and metal coating.
authors: Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 Japan.
authors: Yoko
authors: Y
authors: Asahi
authors: Division for Interdisciplinary Dentistry, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 Japan.
authors: Jiro
authors: J
authors: Miura
authors: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 Japan.
authors: Tetsuya
authors: T
authors: Tsuda
authors: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 Japan.
authors: Susumu
authors: S
authors: Kuwabata
authors: Department of Material Science, Wakayama National College of Technology, 77 Noshima, Nada-cho, Gobo, Wakayama 644-0023 Japan.
authors: Katsuhiko
authors: K
authors: Tsunashima
authors: Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 Japan.
authors: Yuichiro
authors: Y
authors: Noiri
authors: Osaka University Research Center for Ultra-high-voltage Electron Microscopy, Suita, Osaka 565-0871 Japan.
authors: Takao
authors: T
authors: Sakata
authors: Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 Japan.
authors: Shigeyuki
authors: S
authors: Ebisu
authors: Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 Japan.
authors: Mikako
authors: M
authors: Hayashi
keywords: Biofilm; Extracellular polymeric substance; Ionic liquid; Scanning electron microscopy; Streptococcus mutans
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