Fabrication Of Bi-layer Biomimetic Periosteum Materials And Its Induction Of Bone Tissue Regeneration

This paper intends to develop a periosteal material with similar structure and function of autologous periosteum to realize the rapid repair of bone tissue.By imitating the double layer structure of the periosteum and its functional characteristics,Biocompatible silk protein being the base material,Electrostatic spinning and the casting film method being the main method,The external layer loaded with endothelial growth factor and the internal layer loaded with hydroxyapatite were prepared.The microstructure and mechanical properties were tend to be similar to autogenous periosteum by controlling the key processes and parameters.Firstly,the morphology and structure of periosteal materials were characterized.Then the degradation performance,water absorption,mechanical properties,release of growth factors and biocompatibility were detected.The main research methods and results were as follows:(1)To prepared the multi-pore double layer membrane,the double layer structure material was prepared by the method of electrostatic spinning with silk fibroin as base material.With the inner layer loaded with vascular endothelial growth factor and outer layer loaded with hydroxyapatite,the membrane was able to promote bone growth and promote vascularization.The prepared periosteal materials was characterized by SEM,XRD and FTIR.The diameter of silk fibers were approximately 1 ?m.The infrared and XRD shows the structure and the existence of the load factors.The breaking strength and breaking elongation of the double layer membrane were about 6.64 MPa and 10.76%.The mechanical properties of fibroin membranes were improved with the addition of hydroxyapatite but not much affected by the addition of growth factors.The degradation of the double layer membrane in protease solution for two weeks was tend to be with the quality loss of 26% but almost no degradation occurring in the PBS solution.With the addition of hydroxyapatite,the degradation of material performance is reduced.With the increase of VEGF,the degradation of material performance tend to be increased.The water absorption of the double layer membrane was about 60% of the quality of material itself.The degradation of material performance is reduced with the addition of hydroxyapatite and the degradation of material performance is reduced with the increase of VEGF.The VEGF release of the double layer membrane was about 19.6 percent in 2 weeks.The VEGF release rate was fast in the early days and the slowed down as time went on.The total release of VEGF of the double layer membrane were less than the SF/VEGF membrane.The fibroin membrane also shows good biocompatibility;(2)The casting film has better mechanical performance compared with the electrostatic spinning membrane.The casting double layer film were prepared with silk fibroin as base material,of which the inner layer and outer layer of double film respectively loaded with hydroxyapatite and vascular endothelial growth factor.Firstly,the films were characterized by SEM,XRD and FTIR to characterize the morphology and the structure of the films.The breaking strength and breaking elongation of the double layer film were about 12.48 MPa and 13.66%.The mechanical properties of fibroin films were improved with the addition of hydroxyapatite but not much affected by the addition of growth factors.The mechanics performance of the casting films were obvious better than the electrostatic spinning membrane.The degradation performance,water absorption and VEGF release of the film were different with the electrostatic spinning membrane but with the similar effect of the growth factor on the material.The degradation of the double layer membrane in protease solution for two weeks was tend to be with the quality loss of 19.3% but almost no degradation occurring in the PBS solution.The water absorption of the double layer of the film is about 83% of the quality of the material itself.The VEGF release of the double layer film was about 17.3 percent in 2 weeks.The VEGF release rate was fast in the early days and the slowed down as time went on.The total release of VEGF of the double layer membrane were less than the SF/VEGF membrane.The fibroin membrane also shows good biocompatibility;...