Improving the cytocompatibility and functionality of titanium implants by adjusting the electrolyte of the anodization method.

PURPOSE: Titanium implants are widely used in prosthodontics, but their bioinert surfaces can limit early osseointegration. This study examined whether electrolyte-tuned anodization can tailor TiO2 nanotube (TNT) coatings to improve in vitro osteogenesis, angiogenesis, and inflammation-related responses. MATERIALS AND METHODS: Titanium was anodized in three electrolytes to produce TNT, TNT-H, and TNT-B coatings. Morphology and roughness were assessed by scanning electron microscope, phase/chemistry by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and wettability by contact angle. Cytocompatibility and functional responses were evaluated using bone marrow-derived mesenchymal stem cells, human umbilical vein endothelial cells, and RAW264.7 cells, including viability/adhesion assays, macrophage polarization and cytokine expression, and osteogenic/angiogenic assays. RESULTS: TNT-B (mean pore diameter ∼188 nm) showed the most consistent improvements across endpoints, enhancing cell adhesion/proliferation, osteogenesis-associated markers, and angiogenesis-associated signals in vitro, while reducing pro-inflammatory cytokine expression and promoting M2-skewed polarization. TNT-H showed measurable responses versus TNT but did not outperform TNT-B in angiogenic assays under the tested conditions. XRD/XPS indicated minor Ti6O- and defect-related signatures in TNT-B that are relevant to these responses. After annealing, corrosion resistance ranked TNT-H > TNT-B > TNT. CONCLUSIONS: Electrolyte modulation enables the controllable fabrication of TNT architectures and surface chemistry. TNT-B demonstrates promising in vitro performance but exhibits reduced electrochemical stability relative to TNT-H, highlighting a bioactivity-stability trade-off and the need for further optimization and validation before clinical use.