Affiliations: Department of Mechanical Engineering, Faculty of Engineering, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan | Department of Biomaterials and Bioengineering, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8504, Japan | Division of Electronics/Machinery, Tokushima Prefectural Industrial Technology Center, 11-2 Nishibari Saika-cho, Tokushima 770-8021, Japan
Note: [] Corresponding author: Kenzo Asaoka, PhD, Department of Biomaterials and Bioengineering, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8504, Japan. Tel.: +81 88 633-7333; Fax: +81 88 633-9125; E-mail: asaoka@dent.tokushima-u.ac.jp.
Abstract: The biological properties of a titanium (Ti) implant depend on its surface oxide film. The aims of the present study were to increase the specific surface oxide area on Ti using a porous structure and to study the relationship between the amount of apatite coating in simulated body fluid (SBF) and the actual surface area on titanium powders. Ti powders of 110 μm average diameter were sintered by spark plasma sintering. The sintered compacts had a porosity of 28%, a compressive elastic modulus of 7.9 GPa and an ultimate strength of 112 MPa. The compressive strength of the compacts was increased to 588 MPa by subsequent annealing in a vacuum furnace at 1000°C for 24 h. The sintered compacts were treated with aqueous NaOH solution and subsequently heated at 600°C. The pretreated compacts showed apatite crystal precipitation in SBF. The amounts of precipitates through the compacts were compared with those of the Ti plate substrates subjected to the same chemical pretreatment. It was confirmed that the amounts of precipitates through the compacts were more than one hundred times higher than those on the Ti plates. It was concluded that the metal porous compacts developed may be used as functional materials for immobilizing functional proteins and/or drugs, because the precipitated apatite can adsorbed these substances.
Keywords: Titanium, porosity, mechanical properties, metal surface treatment, SBF (simulated body fluids)
