Assessment of cytotoxicity and antibacterial effects of silver nanoparticle-doped titanium alloy surfaces

Objectives: This study aimed to develop silver nanoparticle (AgNP)-doped Ti₆Al₄V alloy surfaces and investigate their antibacterial properties against representative periopathogens and potential cytotoxicity on osteoblastic cells.

Methods: AgNPs of different size distributions (5 and 30nm) were incorporated onto the Ti₆Al₄V surfaces by electrochemical deposition, using colloid silver dispersions with increasing AgNP concentrations (100, 200 and 300ppm). The time-course silver release from the specimen surfaces to cell culture media was assessed by Atomic Absorption Spectroscopy (AAS). Cell attachment, viability and proliferation were investigated by SEM, live/dead staining MTT and BrdU assays. The antibacterial effects were assessed against P. gingivalis and P. intermedia by serial dilution spotting assays.

Results: A time- and concentration-dependent silver release from the experimental surfaces was observed. Overall, cell viability and attachment on the AgNP-doped surfaces, suggested adequate cytocompatibility at all concentrations. A transient cytotoxic effect was detected at 24h for the 5nm-sized groups that fully recovered at later time-points, while no cytotoxicity was observed for the 30nm-sized groups. A statistically significant, concentration-dependent decrease in cell proliferation rates was induced at 48h in all AgNP groups, followed by recovery at 72h in the groups coated with 5nm-sized AgNPs. A statistically significant, concentration-dependent antibacterial effect up to 30% was confirmed against both periopathogens.

Significance: This study sheds light to the optimal size-related concentrations of AgNP-doped Ti₆Al₄V surfaces to achieve antibacterial effects, without subsequent cytotoxicity. These results significantly contribute to the development of antibacterial surfaces for application in oral implantology.