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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 30 nm) were incorporated onto the
Ti6Al4V surfaces by electrochemical deposition, using colloid silver dispersions with increasing
AgNP concentrations (100, 200 and 300 ppm). 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 24 h for the 5 nm-sized groups that fully recovered at later time-points,
while no cytotoxicity was observed for the 30 nm-sized groups. A statistically significant,
concentration-dependent decrease in cell proliferation rates was induced at 48 h in all AgNP
groups, followed by recovery at 72 h in the groups coated with 5 nm-sized AgNPs. A statistically
significant, concentration-dependent antibacterial effect up to 30% was confirmed
against both periopathogens.