title: Effect of ammonia or nitric acid treatment on surface structure, in vitro apatite formation, and visible-light photocatalytic activity of bioactive titanium metal.
abstract: Ti metal treated with NaOH, NH4OH, and heat and then soaked in simulated body fluid (SBF) showed in vitro apatite formation whereas that treated with NaOH, HNO3, and heat and then soaked in SBF did not. The anatase TiO2 precipitate and/or the fine network structure formed on the surface of the Ti metal treated with NaOH, NH4OH, and heat and then soaked in SBF might be responsible for the formation of apatite on the surface of the metal. The NaOH, NH4OH, and heat treatments might produce nitrogen-doped TiO2 on the surface of the Ti metal, and the concentration of methylene blue (MB) in the Ti metal sample treated with NaOH, NH4OH, and heat decreased more than in the untreated and NaOH- and heat-treated ones. This preliminary result suggests that Ti metal treated with NaOH, NH4OH, and heat has the potential to show photocatalytic activity under visible light.
authors.affiliation: Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579, Japan. Electronic address: m-kawa@ecei.tohoku.ac.jp.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kawashita
authors.affiliation: Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Matsui
authors.affiliation: Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu 808-0196, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Miyazaki
authors.affiliation: Liaison Center for Innovative Dentistry, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Kanetaka
mesh_terms: D000641:Ammonia / Q000494:pharmacology*; D001031:Apatites / Q000737:chemistry*; D001672:Biocompatible Materials / Q000494:pharmacology*; D002384:Catalysis / Q000528:radiation effects; D008027:Light; D008751:Methylene Blue / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D017942:Nitric Acid / Q000494:pharmacology*; D056951:Photoelectron Spectroscopy; D013499:Surface Properties; D014025:Titanium / Q000494:pharmacology*; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; D001672:Biocompatible Materials; D017942:Nitric Acid; D000641:Ammonia; D014025:Titanium; D008751:Methylene Blue
keywords: Apatite; Nitrogen; Simulated body fluid; Titania; Titanium metal; Visible-light photocatalytic activity