Study On The Orientation Of Silk Fibroin/ Hydroxyapatite Scaffold For Bone Mesenchymal Stem Cell Adhesion And Proliferation

Because of the special anatomic structure and position, maxillofacial bone is vulnerable to fracture. Although the risk of maxillofacial fractura is inferior to the brain and other vital organs injuries, patients will suffer more than other parts of the damage with the masticatory function limitation,facial appearance changes and the accompanying social psychological barriers. The incidence rate of maxillofacial fractura in recent years increases year by year, and the injury degree becomes more aggravating and complex. The traditional "trauma treatment" gets a great challenge. With the development of tissue engineering, the use of composite porous scaffolds in the field of biomedical materials provides a new idea for maxillofacial trauma repair. The silk, with its excellent abrasion resistance, great biocompatibility, controllable degradation rate and unique physical and chemical properties, is widely used in the field of tissue engineering, especially for tissue repair. However, due to the special jaw anatomy and functional morphology of high standard recovery, tissue engineering materials need to be designed separately for the mechanical properties and biocompatibility according to the characteristics of maxillofacial fractura repair. The method of improving the mechanical properties of the scaffolds and maintaining great biocompatibility and osteoinduction is more conducive to the repair of maxillofacial tissue trauma,which is a great challenge for us. The purpose of this study tries to find a new two element composite porous scaffold and delves into its biocompatibility. The porous scaffolds which consists of the oriented silk fibroin(SF) and hydroxyapatite particles(HA) is short of SF/HA scaffold.Fiber is the natural polymer chaining together, where the molecular chain arrangement and pile formed by the aggregation structure plays an important role on the mechanical properties. The aggregation structure of silk fibers includes the crystalline structure, amorphous structure and orientation structure. Especially for the orientation structure makes significant changes in the mechanical properties of silk materials. Therefore, this study finds the way first to get the 3D insoluble silk fibroin scaffolds in electrophoresis by fiber self-assembility, which has a great elasticity and high mechanical performance. Scanning electron microscopy(SEM) results shows that the scaffold fiber diameter is about 10 um, and the fiber is oriented arrangement with 3D structure.Secondly, we learn the biomimetic mineralization of the oriented silk fibroin. The oriented silk fibroin is immersed in simulated body fluid(SBF), and then we observes the effect of biomimetic mineralization on samples. The Xrd and ICP analysis and scanning electron microscopy(SEM) results show that the calcium phosphorus in the biomimetic mineralization is calcium deficiency apatite in the amount of time; and 3D structure of hydroxyapatite seems to be interconnected and porous.Finally,we learn the effect of porous scaffolds on rat bone mesenchymal stem cell adhesion and proliferation. Confocal microscopy and scanning electron microscopy results indicate that oriented silk fibroin / hydroxyapatite scaffold in this study has an obvious active effect on the bone mesenchymal stem cell adhesion and proliferation with the orientation of the cell growth. DNA quantitative analysis results further demonstrate the biocompatibility of silk fibroin scaffold.Conclusion: The oriented silk fibroin / hydroxyapatite scaffold in this experiment put forward a new kind of biocompatibility and great mechanical properties of the materials to tissue engineering and tissue repair. The experiment has optimized the original method to realize the further design of silk protein properties, providing a new perspective for the application of silk fibroin in tissue engineering.