Nitrided Ti-6Al-4V: A Catalyst for Increase Mineralization and Osteogenic Marker Expression

Plasma nitriding is one of the surface modifications that show more effectiveness than other methods. In this study, the plasma-based ion implantation (PBII) technique was performed on the surface of titanium alloy (Ti-6Al-4V, Ti64) using a mixture of nitrogen (N₂) and argon (Ar), resulting in a plasma-nitrided surface (TiN-Ti64). The surface composition of the TiN-Ti64 was verified through X-ray photoelectron spectroscopy (XPS). TiN-Ti64 demonstrated superior hydrophilicity compared with Ti64. TiN-Ti64 exhibited higher surface hardness than the original surface. The biological responses of primary human alveolar bone cells (hAVs) were observed on the TiN-Ti64, revealing greater activation of cell adhesion and spreading compared with Ti64 and the control group (glass coverslip). Moreover, the TiN-Ti64 significantly promoted cell proliferation compared with Ti64 and tissue culture plates. The mineralization of hAVs on the TiN-Ti64 showed a significant increase, almost 20% greater than that of Ti64. Furthermore, a significant upregulation of mRNA expression for osteogenic differentiation marker genes, including BMP2, OCN, OPN, and RUNX2, was observed in TiN-Ti64 compared with other conditions. In addition, the TiN-Ti64 exhibited antibiofilm activity against Streptococcus aureus. In conclusion, the TiN-Ti64, modified with the PBII technique utilizing a mixture of N₂ and Ar, emerges as a promising alternative for surface modification in dental implant applications.