Study Of TiCu/TiCuN Multilayer Films With Antibacterial Activity And Biocompatibility

Objective: Three differently designed multilayer films of Ti Cu/Ti Cu N multilayer(M1,M2 and M3)were deposited on 316 L stainless steel surface using the axial magnetic field-enhanced arc ion plating(AMFE-ARP)method,which were fabricated for dental application that is expected to efficiently restrain the growth of bacteria and discourage biofilm formation.The aim of this study was to investigate both cytocompatibility and antibacterial activity of the multilayer films.Materials and Methods: Staphylococcus aureus and Escherichia coli were selected to evaluate the antibacterial activity of the multilayer films and Ti N was served as the control.The antibacterial rate,attached bacteria and developed biofilms were studied from quantitative antibacterial test and bacterial morphological examination.The amounts of Cu ions released from the surface of different films in 0.9% Na Cl solution at 1,3,7 and 30 days were measured by ICP-MS.The concentrations of Cu2+ ions increased with increasing the immersion time,which was because Cu was corroded out together with the film due to the slow corrosion effect while immersing in the 0.9% Na Cl solution.The in vitro biocompatibilitiesy of the films with the mouse embryonic osteogenic precursor cells(MC3T3E1)of the prepared alloys wereas systematically investigated by means of methods of CCK8 cell proliferation assay,phalloidin cytoskeleton staining and Annexin-V/PI flow cytometry.Results: The antibacterial rates against both S.aureus and E.coli all reached up to 99%.These results indicated that Cu-containing films possessed excellent antimicrobial activity against both S.aureus and E.coli.Typical 3D CLSM photographs of live bacteria/dead bacteria staining test and the proportion of live bacteria and dead bacteria after incubating with different films are illustrated.It was observed that the formed biofilm containing numerous dead bacteria(red)were observed on the surface of Cu-containing films,but numerous live bacteria(green)were found on the surface of the single Ti N film,indicating that the Cu-containing films possessed excellent anti-biofilm abilities against S.aureus.For all the Cu-containing films,on the short-term of day 1,the concentration of released Cu2+ions was about 0.036-0.064 ?g/m L.It was observed that the concentration of Cu2+ions released from the M1 multilayer film was significantly lower than that of other Cu-containing films on day 1,3,7 and 30.Cell proliferation evaluation by the CCK-8 assay revealed that there was no significant difference in cell viability between the S-Ti N film and other Cu-containing films during the tested periods of 1,3 and 7 days,indicating that the Cu-containing films possessed good cytocompatibility compared to the S-Ti N film.Cell morphology observation suggested that the Cu-containing films were suitable for cells to attach.Conclusion: Ti Cu/Ti Cu N multilayer films showed good cytocompatibility and antibacterial activity.The multilayer films have great application potential as an antibacterial coating on medical implants.