Effect of bioactivity of surface topography and coating forming by infrared light-induced on titanium for bone repair

Calcium ions and phosphate ions are usually present in biological organisms and human bodies. Different ratios of calcium to phosphorus result in different types of calcium-to-phosphorus crystals. Hydroxyapatite (HA) is the main component of human hard bony tissues. It has good biocompatibility and is often used in bone repair. With the addition of cobalt ions, it can act as a hypoxia-inducing factor to accelerate the regeneration of hard bony tissues. At present, the laser-assisted biomimetic (LAB) method can very quickly deposit calcium phosphate coatings, which can be used on polymer and titanium surfaces. In this study, we first used anodization treatment (with TiO2 nanotubes (TNTs)), alkali treatment (with NaOH), and acid treatment (with HCl) to form nanopore structures on titanium surfaces in the laboratory. Subsequently, LAB treatment was used to deposit calcium phosphate and cobalt-substituted hydroxyapatite onto titanium pieces with different surface treatments. The results showed that smaller holes resulted in better deposition (TNTs), and controlling the pH value in the solution changed the crystal morphology. LAB treatment imbued the titanium surface with super-hydrophilic properties and improved biocompatibility. A human osteoblast cell line (MG-63) used for the cell viability test showed that LAB treatment can improve cell growth. In particular, TNT-CoHA (cobalt-substituted hydroxyapatite) cells grew the best. Immersion in simulated bodily fluid confirmed that LAB treatment with a CoHA solution improved the hydrophilicity, biocompatibility, and bioactivity of titanium surfaces. It is hoped that this study provides useful information for surface coating of biomedical materials in the future.