Ultrafine-grained Ti31Mo alloy and Ti31Mo5HA, Ti31Mo5HA-Ag (or Ta2O5, CeO2) composites with a grain size of approximately 2 μm were produced by the application of mechanical alloying and powder metallurgy. Additionally, the surface of the Ti31Mo alloy was modified. In the first stage, the specimens were immersed in 5M NaOH for 24 h at 60 °C. In the second stage, hydroxyapatite (HA) was deposited on the sample surface. The cathodic deposition at -5 V vs. open circuit potential (OCP) in the electrolyte containing 0.25M CaNa2-EDTA (di-calcium ethylenediaminetetraacetic acid), 0.25M K2HPO4 in 1M NaOH at 120 °C for 2 h was applied. The bulk Ti31Mo alloy is a single β-type phase. In the alkali-modified surface titanium oxide, Ti3O is formed. After hydrothermal treatment, the surface layer mostly consists of the Ca10(PO4)6(OH)2 (81.23%) with about 19% content of CaHPO4·2H2O. Using optical profiler, roughness 2D surface topography parameters were estimated. The in vitro cytocompatibility of synthesized materials was studied. The cell lines of normal human osteoblasts (NHost) and human periodontal ligament fibroblasts (HPdLF) was conducted in the presence of tested biomaterials. Ultrafine-grained Ti-based composites altered with HA and Ag, Ta2O5 or CeO2 have superior biocompatibility than the microcrystalline Ti metal. NHost and HPdLF cells in the contact with the synthesized biomaterial showed stable proliferation activity. Biocompatibility tests carried out indicate that the ultrafine-grained Ti31Mo5HA composites with Ag, Ta2O5, or CeO2 could be a good candidate for implant applications.
Keywords: MTS assay; Ti31Mo alloy; biomaterials; cell proliferation; hydroxyapatite; metal matrix composites; ultrafine grain.