| The material surface properties (e.g. roughness, chemical composition, microstructure),could directly affect the implants biocompatibility and biological activity. Titanium and itsalloys have been extensively used as bone implants over recent decades because of theirgenerally excellent biocompatibility, high machinability and good corrosion resistance. Thenanotopographies on Ti-based implant surface have attracted considerable attention.Therefore, the influence of the surface properties of titanium surface is the key to thebiological properties of titanium as bone repair material. Recently, the nanotopographies ofimplants have been widely used to provide useful information regarding bone cell response.The nanotopologies of Ti-based metal implant surface can improve the osseointegrationbetween material surface and host tissue, and improve the specific biological response to thesurrounding environment. In our work, We have fabricated the Ti-RNAs by utilizinggalvanostatic anodization in NH4F and H2C2O4mixed solution as electrolyte at the roomtemperature. Besides, the Ti-RNAs’ density could be tuned periodically by tailoring theelectrochemical time. To the best of our knowledge, these results have not been reportedpreviously. We also analysis the effects of current value, temperature of electrolyte, H+and F-concentration on Ti-RNAs’ density and proposed a possible mechanism to explain theformation of Ti-RNAs with periodic density.Numerous studies have illustrated that proteins and cells were sensitive to nano-sizetopographies and that diverse type of proteins and cells responded diversely to identical sizeof nanotopographies. However, the size of Ti-RNAs that is more favorable for the mostcommon cells around bone implant-osteoblasts, and possible mechanisms of Ti-RNAs’density and length affecting on them are still not clear now. Density and length controlled ofTi-RNAs were formed on the polished pure titanium surfaces using anodization, and theireffect on bone bioactivity, protein adsorption and the biological behavior of osteoblast werestudied to provide a theoretical basis for screening of a nanorod-like structure that wassuitable to the different parts of the bone implant. The surface topographies of samples andcell spreading morphologies were observed using FE-SEM; Contact angle measurementswere performed by measuring and surface energy were calculated using; Osteoblast adhesion was assessed by the method of staining and counting with fuorescence microscope; wasobserved using FE-SEM; osteoblasts proliferation was assessed using MTT assay; ALPactivity of osteoblasts was assessed using commercial kits. The results demonstrated that theTi-RNAs’ surfaces were contributed to the bone bioactivity of Ti surface to some extent, Thedensity and length of Ti-RNAs would affected the biological activity, protein adsorption andMC3T3-E1osteoblast compatibility of titanium surface. The Ti surface with the Ti-RNAs’density of (1.79±0.04)×1010/cm2, and the length of100nm, which not only could facilitatedbone-like apatite nucleation and showed better crystallinity; but also promoted proteinadsorption and had good osteoblasts compatibility.Implant coating with dual functions of antibacterial ability and high bioactivity issupposed to prevent infection and elongate the service life of the dental implants. We believethat silver is better for antibacterial coating application because it owns many advantages suchas broad antibacterial spectrum, good bioactivity at suitable dose, good stability and low riskof resistance development. Because the effective dose of silver is every low, long-termantibacterial ability can be obtained by loading enough amount of silver and controlling itsrelease. In our work, finally, the nano-silver successfully taken to Ti-RNAs’ surface by theoxidation reduction effect of polydopamine. The results illustrated that we have managed tomake the nano-silver loaded onto the surface of the Ti-RNAs. Moreover, while maintained thebioactive of Ti-RNAs, improved its antibacterial properties. The antibacterial rate of thegolden staphylococcus aureus and escherichia coli was as high as100%. Ti nanorod arraysstructure which has the dual function of antibacterial properties and biological activitieswould be likely to get very important applications in the field of implant biomaterials. |
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