Construction Of Surface Microstructure And Osteogenic Properties Of 3D Printed Titanium Implants

Osteomuscular diseases such as osteoporosis,bone tumor and bone defect are a common disease in the middle and old age.The most effective medical treatment for this musculoskeletal disease is surgical treatment with bone implants,but the biocompatibility and mechanical properties of bone implant materials are required.At present,the most commonly used commercial standardized implants are prone to problems such as stress shielding and implant loosening due to high strength and size mismatch,which may lead to implantation failure.The surface structure of the 3D printed titanium orthopedic implant not only reduces the mechanical strength of the material and enhances the bonding strength of the implant with the body,but also it can be customized according to the patient’s injury site.The embodiment of 3D printed titanium orthopedic implantation has become a hot topic in clinical medical field.In this thesis,CP-Ti and SLM-Ti were compared,and the surface morphology and wettability of the two materials were compared by scanning electron microscope and contact Angle measuring instrument.The relationship between CP-Ti and SLM-Ti and cell behavior was investigated by in vitro cell experiments.However,since titanium is a bioinert material and its surface first interacts with tissue cells after implantation in the body,it is necessary to conduct biomodification treatment on the surface of titanium to enhance the biocompatibility and osseogenesis of 3D-printed titanium orthopedic implants.The surface of CP-Ti and SLM-Ti materials was modified by anodic oxidation technology.The micro-rough structure of CP-TiO₂and micro-nano structure of SLM-TiO₂were prepared under different oxidation conditions.The relationship between CP-TiO₂and SLM-TiO₂materials and cell behavior was explored through cell experiments in vitro.After experimental verification,a conclusion is drawn:（1）CP-Ti presents a flat surface,and SLM-Ti is scattered with spherical convex structures with a diameter of 20-50μm and an average interval of 50-150μm.The static water contact Angle of CP-Ti surface is 50.14°±0.3°.The static water contact Angle of SLM-Ti surface is 90.39°±0.18°.The surface of CP-Ti material is hydrophilic and the surface of SLM-Ti material is hydrophobic.CP-Ti material surface can promote the adhesion of osteoblasts（MC3T3-E1）,when osteoblasts（MC3T3-E1）were inoculated on CP-Ti material surface for 4 hours,the cells can immediately adhere to the material surface.CP-Ti material surface greatly promoted the proliferation of osteoblasts（MC3T3-E1）,while SLM-Ti material surface had little effect on the proliferation of osteoblasts（MC3T3-E1）.The osteogenic differentiation ability of MC3T3-E1 cells induced by SLM-Ti was greater than that of CP-Ti.（2）CP-TiO₂micro-nano structure was constructed on the surface of CP-Ti material by anodic oxidation technology,and SLM-TiO₂micro-nano composite structure was constructed on the surface of SLM-Ti material by anodic oxidation technology in one step.With the increase of oxidation voltage,the diameter of SLM-TiO₂nanotubes increases and the hydrophilicity increases gradually.（3）The biocompatibility and osseogenesis of CP-TiO₂and SLM-TiO₂materials were verified by in vitro cell experiments.SLM-TiO₂surface micro-nano composite structure plays an important role in promoting the adhesion and spreading of osteoblasts.Osteoblasts（MC3T3-E1）had a large number of filamentous pseudopods and lamellar pseudopods on the surface of SLM-TiO₂,and the cells grew in a multilateral shape.The surface of CP-TiO₂and SLM-TiO₂can greatly promote the proliferation of osteoblasts（MC3T3-E1）.The osteogenic differentiation ability of MC3T3-E1 cells induced by SLM-TiO₂was greater than that by CP-TiO₂.The ALP activity of MC3T3-E1 cells on the surface of SLM-TiO₂at day 14 was significantly higher than that on day 7,and SLM-TiO₂had the strongest osteogenic differentiation ability of MC3T3-E1 cells at 70V.