In clinical practice, autologous or allogeneic bone transplantation has been widely used in bone defect repair. Therefore, various artificial bone materials, including metal materials and polymer materials, have attracted extensive attention. The Ti-Ta-Nb-Zr alloy has the best corrosion resistance, tantalum and niobium have the ability to promote bone regeneration, and zirconium can change the lattice structure of the alloy to improve higher strength. However, the scaffolds made by traditional methods have some shortcomings, such as irregular pore size, inappropriate mechanical properties and poor connectivity between holes. Therefore, considerable efforts have been devoted to modifying the porous structure and mechanical properties of Ti-Ta-Nb-Zr implants.
With the development of 3D printing technology, different morphologies of implants can be obtained by using computer-aided design models and computer imaging data. Among several existing 3D printing technologies, SLM has been widely used for its stability and accuracy. The researchers first printed Ti-6Al-4V porous scaffolds and Ti-Ta-Nb-Zr alloy scaffolds using SLM technology. Then the mechanical properties were tested and the materials were characterized. Finally, the osteogenic activity and osseointegration ability of the scaffolds were compared by cell culture. In cell proliferation and adhesion experiments, CCK-8 analysis was used to evaluate the proliferation of cells implanted on scaffolds. The results showed that the number of cells in porous Ti-Ta-Nb-Zr alloy group and porous Ti6Al4V group increased with the increase of culture time. The results showed that the scaffolds prepared by SLM had good biocompatibility. In semi-quantitative analysis, there was no significant difference in cell activity on the porous scaffold at day 1, but on days 3, 5, and 7, the Ti-Ta-Nb-Zr alloy group showed significantly higher cell activity than the Ti6Al4V group.
Mineralized nodules were formed in both groups, and the formation level of calcium nodules in Ti-Ta-Nb-Zr alloy group was higher than that in Ti6Al4V group. The results showed that the new porous Ti-Ta-Nb-Zr alloy scaffold enhanced the expression of osteogenic genes and promoted the osteogenic differentiation of hBMSCs.
Implants fixed in bone are designed to restore bone function loss, provide a bridge to repair bone defects or fractures, and have a wide range of clinical applications. The main properties that these implants must possess are adequate mechanical strength, excellent biocompatibility, and the ability to accelerate bone repair and integration. The experimental results show that the porous Ti-Ta-Nb-Zr alloy scaffolds prepared by SLM have the above advantages in repairing bone defects in vitro and in vivo. Therefore, the new three-dimensional porous Ti-Ta-Nb-Zr alloy scaffold has a better effect on promoting bone regeneration and osseointegration than the traditional three-dimensional porous Ti6Al4V scaffold, which has a good development prospect in orthopedic implants.
