title: Characterization of titanium dioxide nanoparticles modified with polyacrylic acid and H2O2for use as a novel radiosensitizer.
abstract: An induction of polyacrylic acid-modified titanium dioxide with hydrogen peroxide nanoparticles (PAA-TiO2/H2O2NPs) to a tumor exerted a therapeutic enhancement of X-ray irradiation in our previous study. To understand the mechanism of the radiosensitizing effect of PAA-TiO2/H2O2NPs, analytical observations that included DLS, FE-SEM, FT-IR, XAFS, and Raman spectrometry were performed. In addition, highly reactive oxygen species (hROS) which PAA-TiO2/H2O2NPs produced with X-ray irradiation were quantified by using a chemiluminescence method and a EPR spin-trapping method. We found that PAA-TiO2/H2O2NPs have almost the same characteristics as PAA-TiO2. Surprisingly, there were no significant differences in hROS generation. However, the existence of H2O2was confirmed in PAA-TiO2/H2O2NPs, because spontaneous hROS production was observed w/o X-ray irradiation. In addition, PAA-TiO2/H2O2NPs had a curious characteristic whereby they absorbed H2O2molecules and released them gradually into a liquid phase. Based on these results, the H2O2was continuously released from PAA-TiO2/H2O2NPs, and then released H2O2assumed to be functioned indirectly as a radiosensitizing factor.
authors: a Department of Chemical Science and Engineering, Graduate School of Engineering , Kobe University , Nada-ku , Kobe , Japan.
authors: Kenta
authors: K
authors: Morita
authors: b Graduate School of Science , Chiba University , Inage , Chiba , Japan.
authors: Serika
authors: S
authors: Miyazaki
authors: b Graduate School of Science , Chiba University , Inage , Chiba , Japan.
authors: Chiya
authors: C
authors: Numako
authors: c Graduate School of Life Science and Systems Engineering , Kyushu Institute of Technology , Wakamatsu-ku , Kitakyushu , Japan.
authors: Shinya
authors: S
authors: Ikeno
authors: d Division of Radiation Oncology , Kobe University Graduate School of Medicine , Chuou-ku , Kobe , Japan.
authors: Ryohei
authors: R
authors: Sasaki
authors: e Organization of Advanced Science and Technology, Kobe University , Nada-ku , Kobe , Japan.
authors: Yuya
authors: Y
authors: Nishimura
authors: a Department of Chemical Science and Engineering, Graduate School of Engineering , Kobe University , Nada-ku , Kobe , Japan.
authors: Chiaki
authors: C
authors: Ogino
authors: a Department of Chemical Science and Engineering, Graduate School of Engineering , Kobe University , Nada-ku , Kobe , Japan.|e Organization of Advanced Science and Technology, Kobe University , Nada-ku , Kobe , Japan.
authors: Akihiko
authors: A
authors: Kondo
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D011838:Radiation-Sensitizing Agents / Q000737:chemistry*; D017382:Reactive Oxygen Species; D014025:Titanium / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D011838:Radiation-Sensitizing Agents; D017382:Reactive Oxygen Species; C009495:titanium dioxide; D006861:Hydrogen Peroxide; D014025:Titanium
keywords: Titanium dioxide; hydrogen peroxide; nanoparticles; radiation therapy; radiosensitizer; reactive oxygen species