Preparation of CaO@TiO₂-SiO₂ Biomaterial with a Sol-Gel Method for Bone Implantation

The calcium phosphate spherical material with a hierarchical structure has been used as a bone implantation material. To improve the properties of the implant material, the compositions of calcium phosphate, silicon, and titanium are crucial. The presence of silicon on the surface of the phosphate-calcium material accelerates the bonding of the implant with the bone (osseointegration). The aim of this work was to develop a sol-gel method to prepare spherical calcium-phosphate@TiO₂-SiO₂ biomaterials for bone implantation. The CaO@TiO₂-SiO₂ biomaterial with a core-shell structure was synthesized by the sol-gel method. The biological properties of the materials were studied with a simulated body fluid (SBF). The sample had a spherical shape. The sample exhibited bioactive properties because an increase in the content of calcium and phosphorus ions in the shell and the presence of precipitated ions from the solution were detected on the surface. The TiO₂-SiO₂ framework was uniformly fixed on the CaO core. Heat treatment of the hybrid mesostructure led to the formation of mesoporous materials with a specific regular structure in the nanometer size in the shell, which is necessary for the fixation of biological cells when the sample is introduced into the biological medium. The formation of a calcium-phosphate layer on the materials and the release of soluble silicon and calcium ions into the SBF are the key factors for the rapid connection of these materials with tissue. The results demonstrate that the CaO@TiO₂-SiO₂ biomaterial with a core-shell structure is a good candidate for bone implantation.