Influence of Ta2O5 Addition on the Surface Characteristics, In Vitro Bioactivity, and Early Cellular Responses of Single-Layer SLM Titanium-Based Surface Layers

Improving the surface and biological performance of titanium is important for biomedical applications. This study evaluated titanium-based surface layers fabricated on Ti substrates by single-layer selective laser melting (SLM) using commercially pure Ti (CP-Ti) powders containing 0, 1, or 2 wt.% Ta2O5. Surface morphology, composition, roughness, hardness, wettability, simulated body fluid (SBF) deposition, and early MG-63 cell responses were examined. The Ta2O5-containing specimens exhibited lower roughness (3.4–5.0 versus 4.9–6.7 μm), higher hardness (226–239 versus 173 HV0.2), and lower water contact angles (31–33° versus 47°) than CP-Ti. EDS detected Ta and O, while XRD showed weak features consistent with retained Ta2O5. During SBF immersion, Ta2O5-containing specimens showed earlier deposits and greater apparent surface coverage, reaching 100% in analyzed SEM images after 28 days. SEM suggested more extensive MG-63 spreading and filopodial extension, particularly at 24 h. At 24 h, both Ta2O5-containing groups showed higher mean CCK-8 absorbance than CP-Ti, although between-group significance was not established. These findings indicate promising surface properties and early cellular responses, subject to differences in feedstock preparation and processing conditions.