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Productivity of Reactive Oxygen Species by Low-Intensity Focused Ultrasound Irradiation to Titanium Dioxide Particles 酸化チタン粒子への集束超音波照射による活性酸素種生成能 の評価
| Content Provider | Semantic Scholar |
|---|---|
| Author | Hashimura, Keisuke Kaya, Akio Misawa, Masaki Koseki, Yoshihiko Kiyoshi Yoshinaka Nitta, Naotaka |
| Copyright Year | 2016 |
| Abstract | Titanium dioxide (TiO2), known as photocatalyst, produces reactive oxygen species (ROS) such as hydroxyl radical (OH·) by ultrasound irradiation1). Recently, cancer therapy using citotoxicity of ROS produced by ultrasound irradiation to TiO2 particles (sonodynamic thrapy) has been studied2). In addition, TiO2 particles can be applied for infection prevention. In our group, anti-infective catheter system for the exit site of catheter retained in the skin was proposed3, 4). For producing ROS less-invasively, using focused ultrasound is considered to be effective. However, optimal conditions of ROS generation by low-intensity focused ultrasound irradiation have not been investigated. To decide the optimal irradiation conditions, more understanding of mechanism of ROS generation by ultrasound irradaition was required. We hypothesized two mechanisms of ROS generation. One is that TiO2 (anatase type) works as photocatalyst. When rupture of cavitation bubbles occurs, sonoluminescense light including ultraviolet range is emitted5). Anatase type TiO2 is activated by light at the wavelength of 387 nm and OH· is generated. The other is that TiO2 works as a reflector of ultasound. It is reported that cavitation of water can generate ROS such as OH· and singlet oxygen (O2). (O2 is generated under the presense of dissolved oxygen.) When TiO2 particles exists in water, negative sound pressure increases by ultrasound reflection and cavitation threshold became smaller. Therefore, ROS is considered to be generated at less intensity than without particles. In this study, we compared the productivity of ROS by low-intensity focused ultrasound irradiation to TiO2 (anatase type), TiO2 (rutile type), and aluminum oxide (Al2O3) particles by fluorescence measurement, and investigated which mechanism is mainly contributed to ROS generation. 2. Materials and Method |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www.use-jp.org/proceedings/USE16/pdf/2P4-5.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
