Preparation, Characterization And Applications Study Of The N-HA/CS Composites Materials

This paper has four chapters and the main results are as following:In chapter 1:the exordium. Firstly, the characteristc, performance, preparation of the n-HA/CS composites materials were described. Secondly, the applications of the composite materials were introduced in biomedical materials field. Finally, the significance, purpose and mostly content of the study were reviewed.In chapter 2:the n-HA/CS-ChS composite materials were prepared by co-precipitation method, and the composite were analyzied and characterized by means of XRD, SEM, TGA and universal material test machine, and the change of the mineralization surface of the composite, pH and the concentration of system in the simulated body fluid were observed. The results show that the n-HA/CS-ChS composites have small influence on the body microenviroment, a good mineralization effect on the surfaces and an excellent biocompatility and osteoconduction property. The composite can meet the demand of repairation of osteo-tissue engineering and substitute, and will be the loading substituted to treat boned effects.In chapter 3:the n-HA/CS-Alg composite materials were prepared, and the mechanical performance, composition and morphology of the composites were determined by using of UTM, XRD, TEM, SEM and TGA. The results indicated that nano-hydroxyapatite particles had similar chemical composition with nature bone and the composites were dispersed evenly in Chitosan and sodium alginate matrix. The mechanical property of the nano-composite was well with maximum compressive strength value of 47.183 MPa at 50wt% HA of n-HA/CS-Alg. The composites can meet the demands of repairation and substitution of bone tissue and have potential application prospect in internal fixation of bone fracture. Furthermore, the research was helpful for the theoretical development of bone tissue engineering.In chapter 4:In order to prove the avail of the n-HA/CS-ChS composite, every rabbit was prepared implant bed to establish bone defection model on the rabbit tibia, the composites were implanted into the bone defect. The specimens were obtained to observe at respectively 4,8,12 and 16 weeks postoperatively. The n-HA/CS-ChS composite was analyzed and evaluated by means of the general observation, the SEM observation, histological observation and the Micro-CT analysis. The results showed that the newborn blood vessel and the connective tissue had grown into continuously the material areas, the degradation of the materials were found and the whole bone defect areas were filled with the new bone. The bone tissue was reconstructed gradually and tended in mature at the same time. However, the unfilled material areas have no new bone growth and defect interface tidy after 16 weeks. Furthermore the composites can inductive the bone rebirth rebuild defect bone. It has important meaning for the reconstruction of bone tissue and the research of cell biology, at the same time it will provide the new theories basis and technique for the treatment of bone defection, osteoporosis, femur head necrosis. Thus, these materials may prove to be useful for novel applications in the biomedical field.