The Fabrication And Biocompatibility Evaluation Of CP-Ti And Ti-6Al-4V With Micro-to-Nano-scaled Hierarchical Surface

Due to their good mechanical properties,corrosion resistance and good biocompatibility,titanium?Ti?and its alloys,have been widely used as bone substitute materials.However,most Ti and Ti alloys are still classified as bioinert materials in clinical application.The relatively low osseointegration properties of Ti and Ti alloys may result in slow bone repair,Ti implants loose and even failure.Natural bone has highly organized hierarchical structures of micron-scale haversian osteon and nanoscale collagen fibers as well as hydroxyapatite crystals.So from the view of bionics research,the ideal bone implant should be composed of micro-to-nano-scaled hierarchical structure.Micron-scale structure can increase bone-to-implant contact,change the bone's state of strain,and promote the mechanical interlock of bone with implant surface.Appropriate nanoscale surface can not only promote the adhesion and proliferation of bone cell,but also induce osteoblast differentiation of bone marrow mesenchymal stem cells?b MSCs?significantly,therefore inducing bone formation.Hierarchical structures consisting of micron-and nanostructured patterns,cause a synergistic enhancement effect on cell adhesion,proliferation and differentiation,protein synthesis,extracellular matrix mineralization.The powder metallurgy technique provides an effective near-net-shaped way for manufacturing complex shaped components as well as the potential to tailor micron-scale surface roughness by controlling sintering parameters.According to the condition of different patients,implant materials can be custom-made by 3D printing,and materials microstructures also can be precisely controlled.Compared with other nanostructured topologies,the titania?Ti O₂?nanotubes produced by anodic oxidation possess a lot of advantages in the field of biomaterials because of their special structure features.Ti O₂ nanotubes can significantly promote cell adhesion,proliferation and differentiation.In this study,micro-to-nano-scaled hierarchical Ti materials were fabricated by powder metallurgy and 3D printing followed by anodic oxidation respectively.The surface characteristics were measured using field emission scanning electron microscopy,contact angle measurement instrument,X-ray diffraction,and 3D laser scanning microscope.Protein adsorption and a series of cell experiments in vitro were used to evaluate biocompatibility of samples.The results show that,the samples surface with micro-to-nano-scaled hierarchical structure displayed better biocompatibility and improved the r BMSCs adhesion,proliferation and osteoblast differentiation.