| Infection、trauma and congenital malformations often result in maxillofacial bone defects.Although the hazard of maxillofacial trauma is inferior to the life-threatening brain injury,but it will cause changes in facial appearance,chewing functional limitations and associated psychological obstacles,so the patients will suffer more than other parts of the injury.Because of the special position and maxillofacial anatomy,the incidence rate of maxillofacial trauma increased year by year,and the injury is more severe,the traditional "trauma treatment" treatment modalities get a great challenge.With the use of composite porous scaffolds in the field of biomedical materials,tissue engineering is considered as a promising alternative to the maxillofacial trauma repair.The silk fibroin,is the main mineral constituent of natural bone and has been used as a material for tissue engineering due to its excellent biocompatibility,unique mechanical properties and regulated degradation rate,is widely used in the field of tissue engineering.However,due to the special nature of the facial bone anatomy and functional morphology restore,it has very high standards and requirements,and thus tissue engineering materials require special design.The objective of this project is to find a new binary composite porous scaffold and study its biocompatibility.The porous scaffold is made up of oriented silk fibroin(SF)and hydroxyapatite particles(HA),hence the name is SF/HA scaffold.Methods and results: Aggregation of polymer chains form a fiber,so the mechanical properties of the fiber and its aggregation structure has important relevance.Silk fibers include the crystalline,amorphous and orientation structure.,while the orientation structure has an important influence on the mechanical properties.Therefore,this experiment finds the way first to get the 3D silk fibroin scaffold in electrophoresis by fiber self-assembility,which has a good mechanical property and is insoluble in water.Scanning electron microscope observation showed that: the fiber scaffold has a 3D structure,where the diameter of the fiber is10μm,and the fiber has the orderly arrangement of orientation.Secondly,from the perspective of biomineralization,the oriented silk fibroin is immersed in simulated body fluid,and then we observe the effect of biomimetic mineralization.The X-ray diffraction and scanning electron microscopy showed that: hydroxyapatite in the amount of deposit in the oriented silk fibroin is proportional to the concentration of silk fibroin,the calcium phosphorus which is formed by biomimetic mineralization is calcium deficiency type of apatite,and 3D stereoscopic structure of hydroxyapatite seems to be connecting and porous.Finally,The in vitro rat bone mesenchymal stem cell culture results suggested the SF/HA scaffold has good biocompatibility,we also used the SF/HA scaffold as nanocarriers to deliver osteogenic growth factors(Bone morphogenetic protein-2).Confocal microscopy results indicate that the SF/HA scaffold significantly promote the cell adhesion and proliferation,and cells into oriented growth.DNA quantitative analysis results further demonstrate the well biocompatibility of the SF/HA scaffold.Experimental results show that the addition of the bone morphogenetic protein-2 are better able to promote osteogenic differentiation of the mesenchymal stem cells.Conclusion: the present study provided an effective process to prepare the SF/HA scaffold with tunable mechanical properties,better biocompatibility and osteogenic differentiation potential,providing a new perspective for the application of silk fibroin in tissue engineering. |
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