The Antibacterial Activity Comparison Of Carbon-based Nanofilm Coated Titanium Alloy And Co-Cr-Mo Alloy

Objective: To study the in vitro and in vivo properties of titanium alloys coated with carbon-based nanofilms preliminary.Methods: The experiments with two circular flake test specimens,made from carbon-based nanofilm coated titanium alloy and Co-Cr-Mo alloy commonly used in artificial joints was cut into the same specification,respectively,were performed in vitro and in vivo in animals.In vitro experiments were performed by co-culturing the two test specimens with standard strains of Staphylococcus aureus and Escherichia coli,and the antibacterial properties of the two test specimens were evaluated by observing the inhibition zone,scanning electron microscopy to observe bacteria morphology and adhesion situation,fluorescence staining to observe bacteria adhesion situation,and colony forming unit count;the cytotoxicity was evaluated by co-culturing them with rabbit mesenchymal stem cells.In vivo experiments were performed by implanting the two test specimens in the muscle tissue of experimental rabbits to evaluate their tissue compatibility properties from histology.Results: Both in vitro co-cultures of carbon-based nanofilm titanium alloy and Co-Cr-Mo alloy with standard strains Staphylococcus aureus and Escherichia coli,respectively,no obvious inhibition zone was observed around the materials.However,some biofilms can be observed on the surface of Co-Cr-Mo alloys.By scanning electron microscopy and fluorescence staining techniques,fewer bacteria adhered to the novel titanium alloy coated with carbon-based nanofilms can be observed.Meanwhile,the colony forming unit count also showed that the titanium alloy coated with carbon-based nanofilms had less bacterial adhesion than the Co-Cr-Mo alloy.After co-culture of the two materials with rabbit mesenchymal stem cells,there was no significant difference in cell count,and both the cell counts suggested that coated titanium alloy has no cytotoxicity.In the in vivo experiments of animals,there were relatively few giant cells in tissues near the titanium alloy coated with carbon-based nanofilms showed the better histocompatibility.Conclusion: The novel titanium alloy coated with carbon-based nanofilms has stronger antibacterial activity in vitro and better histocompatibility in vivo than Co-Cr-Mo alloy.