Setsuaki Murakami

Calcium Phosphate Porous Materials with Unique Microstructures

Three types of calcium phosphate porous materials were prepared by the applied hydrothermal method. One of them was non-stoichiometric hydroxyapatite (HA) with calcium deficient composition and the others were β-tricalcium phosphate (β-TCP) and HA/β-TCP bi-phase material. Granules with several millimeter in size of calcium deficient HA, β-TCP and HA/β-TCP could be prepared. These granules with porosity over 70 % were composed of rod-shaped particles with aspect ratio about 10. Rod-shaped particles were locked together to make sub-micro-sized pores of about 0.1 to 0.5 µm in size. These materials must be suitable for the bone graft materials and as the scaffolds of cultured bone.

Hydrothermal Preparation of Apatite Composite with Magnetite or Anatase

Microstructure designed porous hydroxyapatite (Ca10(PO4)6(OH)2) composites with magnetite (Fe3O4) particles or anatase (TiO2) dispersion were prepared by hydrothermal treatment. These composites had micro‐pores of about 0.1–0.5 μm in size. Magnetite / Hydroxyapatite composites should be suitable for medical treatment of cancer, especially in bones, because HA can bond to bones directly and magnetite can generate heat. They must be used for hyperthermia therapies of cancer in bones. Meanwhile, anatase / Hydroxyapatite composite should be suitable for environmental purification, because HA rod‐shape particles expose the specific crystal face, which adsorbs organic contaminants and so on.

Porous Composite with Tunnel-like Interconnecting Pores of Hydroxyapatite with Magnetite Particles

Porous composites of magnetite / hydroxyapatite with bimodal pore size distribution were prepared by hydrothermal method. Magnetite particles of about 1 µm in size with polyhedral shape were dispersed into hydroxyapatite porous matrix. The hydroxyapatite particles were rod-shaped crystals and the size of crystals were about 10 µm in length with the aspect ratio of over 25. Rod-shaped hydroxyapatite crystals were locked together to make micro-pores of about 0.8 µm in size. In addition, macro-pores of about 400 µm in size were prepared by our unique method. Hydroxyapatite in this composite was non-stoichiometric hydroxyapatite with calcium deficient composition. This composite must have the advantage of adsorptive activity and osteoconductivity, because the hydroxyapatite has many specific crystal surface and micro-pores. The composites of magnetite / hydroxyapatite must be suitable for the hyperthermia therapy of cancer in bones.