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The evaluation of dentin-coating ability and photothermal antibacterial effect of graphene oxide
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| Title: | The evaluation of dentin-coating ability and photothermal antibacterial effect of graphene oxide |
| Other Titles: | 象牙質の酸化グラフェンコーティングと近赤外線光による光熱抗菌効果 |
| Authors: | 長尾, 敬志 Browse this author |
| Keywords: | antibacterial property | | graphene oxide | | near-infrared irradiation | | photothermal therapy | | Streptococcus mutans |
| Issue Date: | 22-Mar-2018 |
| Publisher: | Hokkaido University |
| Abstract: | Graphene oxide (GO) is a monolayer sheet of carbon with a thickness of 1 nm or less that has high hydrophilicity and dispersibility due to the presence of oxygen functional groups on its surface. Recent studies have revealed that GO exerts antibacterial properties, absorbs near-infrared (NIR) irradiation and generates heat. In this study, we assessed whether GO possessed the ability to cover the dentin. In addition, we investigated the photothermal and antibacterial effects of the GO film on Streptococcus mutans. The dentin block was prepared using extracted human molars. The dentin block was immersed in GO dispersion (concentration: 0,1 and 10 μg/mL). GO-coated dentin blocks were observed using scanning electron microscopy (SEM) and characterized using the dentinal tubule covering score. To assess the stability of the GO film, residual GO on the dentin block was observed after ultrasonic cleaning. Subsequently, the temperature increase of the GO-coated dentin surface following NIR irradiation was examined by thermography. Furthermore, antibacterial effects of the combination of GO film and NIR irradiation against S. mutans were evaluated by SEM observation, turbidity measurement, colony formation assessment and live/dead staining. A thin GO film with a thickness of a few nanometers was successfully formed on the dentin surface by immersion in GO solution. The dentinal tubule covering score increased in a GO concentration-dependent manner. Even after ultrasonic cleaning, GO residue was frequently observed on the dentin surface. When the GO-coated dentin block was irradiated with NIR light, the temperature of the dentin block surface increased in a GO concentration- and time-dependent manner. However, the temperature decreased as irradiation distance increased. Combination of GO application and NIR irradiation could heat the dentin surface to 58.5 °C after 30 seconds of irradiation. In antibacterial assessments, turbidity and colony formation were suppressed by GO and NIR irradiation. In addition, dead bacteria were detected by live/dead staining. A stable GO film was successfully formed on the dentin surface by immersion in GO dispersion. Photothermal and antibacterial effects were remarkably exhibited by GO and NIR irradiation. The GO-NIR system would be beneficial for photothermal antibacterial therapy. |
| Conffering University: | 北海道大学 |
| Degree Report Number: | 甲第13050号 |
| Degree Level: | 博士 |
| Degree Discipline: | 歯学 |
| Examination Committee Members: | (主査) 特任教授 柴田 健一郎, 教授 吉田 靖弘, 准教授 菅谷 勉 |
| Degree Affiliation: | 歯学研究科（口腔医学専攻） |
| Type: | theses (doctoral) |
| URI: | http://hdl.handle.net/2115/73129 |
| Appears in Collections: | 課程博士 (Doctorate by way of Advanced Course) > 歯学院(Graduate School of Dental Medicine)
学位論文 (Theses) > 博士 （歯学）
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