Effect of Ammonia or Nitric Acid Treatment on Surface Structure, in vitro Apatite Formation, and Visible-Light Photocatalytic Activity of Bioactive Titanium Metal

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

Preparation, structure, and in vitro chemical durability of yttrium phosphate microspheres for intra-arterial radiotherapy

Chemically durable microspheres containing yttrium and/or phosphorus are useful for intra-arterial radiotherapy. In this study, we attempted to prepare yttrium phosphate (YPO4) microspheres with high chemical durability. YPO4 microspheres with smooth surfaces and diameters of around 25 μm were successfully obtained when gelatin droplets containing yttrium and phosphate ions were cooled and solidified in a water-in-oil emulsion and then heat-treated at 1100°C. The chemical durability of the heat-treated microspheres in a simulated body fluid at pH = 6 and 7 was high enough for clinical application of intra-arterial radiotherapy

Preparation of porous yttrium oxide microparticles by gelation of ammonium alginate in aqueous solution containing yttrium ions

Porous Y2O3 microparticles 500 μm in size were obtained, when 1 wt%-ammonium alginate aqueous solution was dropped into 0.5 M-YCl3 aqueous solution by a Pasteur pipette and the resultant gel microparticles were heat-treated at 1100°C. Small pores less than 1 μm were formed in the microparticles by the heat treatment. The bulk density of the heat-treated microparticle was as low as 0.66 g cm−3. The chemical durability of the heat-treated microparticles in simulated body fluid at pH = 6 and 7 was high enough for clinical application of in situ radiotherapy. Although the size of the microparticles should be decreased to around 25 μm using atomizing device such as spray gun for clinical application, we found that the porous Y2O3 microparticles with high chemical durability and low density can be obtained by utilizing gelation of ammonium alginate in YCl3 aqueous solution in this study

Preparation, structure, and in vitro chemical durability of yttrium phosphate microspheres for intra-arterial radiotherapy

Chemically durable microspheres containing yttrium and/or phosphorus are useful for intra-arterial radiotherapy. In this study, we attempted to prepare yttrium phosphate (YPO4) microspheres with high chemical durability. YPO4 microspheres with smooth surfaces and diameters of around 25 μm were successfully obtained when gelatin droplets containing yttrium and phosphate ions were cooled and solidified in a water-in-oil emulsion and then heat-treated at 1100°C. The chemical durability of the heat-treated microspheres in a simulated body fluid at pH = 6 and 7 was high enough for clinical application of intra-arterial radiotherapy