| Dental implant is one of the most common methods used in the treatment of dentition defect or missing dentition.Titanium and its alloys are the commonly used materials for dental implant since their good biological and ideal mechanical properties.The porous structure of implant material can simulate the bone structure and promote the adhesion of osteoblasts,but at the same time,it contributes the same opportunity to biofilm formation,which starts immediately after bacterial adhesion during the early stages of implantation.Peri-implant infections and poor osseointegration lead to the loss of tissue support for the implant and sometimes even treatment failure.Therefore,antibacterial and osseointegration-accelerating properties are important in implant modification.Methods: In this study,a micro/nanoporous titanium surface was prepared through alkaline and heat treatments,covalently conjugated with aminosilane.Then,different amounts of chlorhexidine(CHX)were covalently grafted onto the aminosilane-modified surface via glutaraldehyde to obtain different CHX-grafted surfaces(0.1?0.5?1.0mg/m L).These as-prepared surfaces were evaluated in terms of their surface composition by XPS,surface topography by SEM and CHX grafting amount.The antibacterial activity of S.aureus,a most important pathogen on the surface of implant at the initial stage of implantation,was evaluated by Live/Dead staining,plate counting,and crystal violet staining.The compatibility of the constructed surface to the MC3T3-E1 cell was evaluated by MTT and flourscence staining.What's more,the process of implantation was simulated by the bacteria-cell competitive adhesion test to evaluate the importance of the antibacterial properties of materials in the presence of bacteria to ensure successful cell adhesion.Result: The results showed that the CHX grafting amount can increased with increasing CHX concentrations,and affect the conformation of chlorhexidine,leading to better antibacterial activity.Surface characterization which indirectly proved the success graft of chlorhexidine.The surface hydrophilicity was significantly improved compared with silanized surface and CHX(1 mg/m L)resulted in the best antibacterial surface,which still retained good osteoblast compatibility.Meanwhile,competitive bacterial-cell adhesion analysis demonstrated that this surface has great value for osteoblast adhesion at the implant-bone interface even in the presence of bacteria.At the same time,the conformation change of chlorhexidine at high concentration can obviously improved the biocompatibility.The result showed that the graft surface of chlorhexidine could not only inhibit the colonization of bacteria on the surface of the material and kill the adhesive bacteria but also inhibit proliferation of bacteria around the material.The antibacterial ability of the coating increased with the graft amount of chlorhexidine.Sample with the graft amount of chlorhexidine was 3.98±0.31 g(the concentration of the reaction solution was 1mg/m L)showes the best antibacterial ability,The result of cytocompatibility evaluation showed that the graft of chlorhexidine did not result in significant cytotoxicity,and the cytotoxicity decreased with the increase of CHX concentration.The evaluation result of bacteria-cell competitive adhesion showed that chlorhexidine modified surface provided a guarantee for cell adhesion in the process of competition between bacteria and cells.Conclusion: The above results suggest that the commonly used oral sterilization drug CHX has been modified into implant surface can also effectively inhibit bacterial contamination.And this simple,environment friendly modified method by glutaraldehyde and silane coupling to porous titanium surface grafting CHX can not only with a good antimicrobial and cell compatibility but also a high utilization rate of chlorine.Subsequently,this coating has a potential application value in the surface modification of implants and repair materials. |
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