Fabrication and characterization of novel porous titanium microspheres for biomedical applications

Microsphere systems have been widely used in the treatment of defective tissues, including bone, cartilage, and muscle. Although researchers are interested in porous calcium-phosphate microspheres, no articles that discuss the preparation of porous Ti microspheres are present in the literature. In the current study, porous Ti microspheres were successfully fabricated via a water-in-oil emulsion technique using camphene as a porogen and a tailored sintering schedule. The results show that the porous Ti microspheres exhibited an interconnected porous structure with pore sizes ranging from several microns to as large as 200 μm, and with various porosities from 49.1% to 74.3%. More than 65% of the pores were larger than 50 μm. Additionally, the surfaces of Ti microspheres were modified with NaOH treatment, and then the calcium-phosphate forming ability in simulated body fluid (SBF) solution was investigated to assess bioactivity. After NaOH treatment, the Ti microsphere exhibited a porous network structure, which is a sodium hydrogen titanate reaction layer as confirmed by the XRD results. A dense and uniform calcium-phosphate layer covered the surface of the NaOH-treated Ti microsphere after it was soaked in SBF solution for 14 days. However, there is no obvious formation of calcium-phosphate on the surface of the untreated Ti microsphere even after it was soaked in SBF for 14 days.