Preparation Of Bone Tissue Engineering Scaffolds With Different Topological Structure And Evaluation Of Their Biological Properties

Bone defect is a serious clinical problem in orthopaedic field. To solve this problem, tissue engineering is a promising method. One of the most important aspects of tissue engineering is scaffold. The biological properties of tissue engineering scaffold are influenced by many factors such as topological structure, which makes sense to research the effects of topological structure on the biological properties of tissue engineering scaffold. In this dissertation, various scaffolds with different topological structure were prepared, including poly phosphozene films, PLLA/CNM composite nanofibrous scaffolds, bioglass-incorporated carbon nanofibers and fluorescent nanofibers. The biological properties of these scaffolds were evaluated by in vitro and/or in vivo experiments. And the effects of bioactive components such as carbon nanomaterials and bioglass nanoparitcles were also studied. In addition, the tracing method of biodegradable scaffold was also preliminarily studied.In order to evaluate to biological properties of scaffolds, we cultured osteoblast and murine BMSC. The cells used in this dissertation had good activity, high purity and osteogenuous potential.The PGAP films with different topological structure were prepared by casting under different humidities. The PGAP6-80 and PGAP 12-80 which were cast under high humidity had honeycomb-like topological structure, while PGAP6-20 and PLGA 6-20 which cast under low humidity had flat surface. The ability of protein absorption was related to surface roughness. The PGAP films were hydrophilic because of their high content of phosphorus and nitrogen elements on the surface. The PGAP films had good ability of inducing biomineralization in simulate body fluid, and PGAP 12-80 with high roughness and phosphorus content had the strongest biomineralization-inducing ability. The in vitro experiment proved that PGAP promoted osteogenuous differentiation of MC3T3-E1 cells rather than adhesion and proliferation.The PLLA nanofibrous scaffolds were prepared by phase separation method. The scaffolds had complex nanofibrous structure which resemble the natural extracellular matrix. Carbon nanotube and graphene were incorporated into PLLA nanofibrous scaffolds and dispersed evenly in the scaffolds. The results of in vitro and in vivo experiments showed that the nanofibrous topological structure and carbon nanomaterials had good effects on cell adhesion and proliferation of BMSC, and also had the ability of osteogenuous induction. The incorporation of carbon nanomaterials improved the biological properties of PLLA nanofibrous scaffolds. Graphene had stronger effects than carbon nanotube, and these effects were in proportional to the content of carbon nanomaterials.The topological structure of carbon nanofibers was controlled by different receiving devices in electrospinning process. By this method, aligned and random carbon nanofibers was prepared. The results of in vitro experiments indicated that the aligned carbon nanofibers were more suitable for the application of bone tissue engineering. The bioglass nanoparticle-incorporated carbon nanofibers with aligned topological structure were prepared by sol-gel method, electrospinning, stabilization and carbonization. The sol-gel comprised TEP, TEOS and Ca(NO3)2, and the sol-gel was resolved in PAN (Mw=105) solution. The results of in vitro and in vivo experiments revealed that the 68S bioglass-incorporated carbon nanofibers had the best osteocompatibility.The fluorescent nanofibers were prepared by electrospinning of PLLA and d-p48 fluorescent molecule. The nanofibers had strong and stable fluorescence. The d-p48 molecules were not dispersed out of the nanofibers before the nanofibers degraded. After being implanted into mouse for two weeks, the fluorescence of nanofibers was also strong and could trace the nanofibers. In addition, the fluorescent nanofibers had no obvious toxicity to the body.To sum up, the topological structure has important effects on the biological properties of bone tissue engineering. And the bioactive components such as carbon nanomaterials and bioglass also could improve the biological properties of bone tissue engineering.