Antibacterial Efficiency and Osteoblast Viability of Ag/AgO/Ag2O Nanoparticles on Microarc-Oxidized TiO2

Infections associated with titanium-based medical and dental implants present a major clinical challenge, as they can compromise osseointegration and long-term implant stability. Silver-based nanoparticles (NPs) are widely recognized for their strong antimicrobial properties, and when combined with titanium, they hold significant promise for developing infection-resistant and biocompatible implant surfaces. In this study, Ag/AgO/Ag2O NPs were deposited onto highly porous TiO2 layers formed on the Ti6Al4V alloy by microarc oxidation (MAO), with the aim of simultaneously enhancing antibacterial performance and supporting osteoblast activity. The NPs exhibited a predominant size of 8.7 ± 0.1 nm, with smaller particles oxidized to AgO and Ag2O, and larger particles (∼10 nm) composed of metallic Ag. SEM evaluation revealed that the NPs were homogeneously dispersed across the oxide surfaces without altering the rough and porous morphology of TiO2. The MAO-treated surfaces initially showed hydrophobic behavior (contact angle of 94.1 ± 0.3°), which shifted to hydrophilic after Ag/AgO/Ag2O NP deposition due to increased hydroxyl group formation. Antibacterial assays against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) revealed a significant enhancement in antibacterial activity, particularly for surfaces with the highest Ag/AgO/Ag2O NP density. Meanwhile, osteoblast cell viability assays demonstrated no reduction in metabolic activity after 72 h, and SEM images confirmed cell adhesion and proliferation. Overall, these findings highlight the potential of Ag/AgO/Ag2O NP-modified TiO2 surfaces as multifunctional coatings that combine infection resistance with osteoblast compatibility, offering promising applications in dental and orthopedic implants.