| BackgroundDefects of the chest wall always occur as a result of excision of neoplasm (primary and recurrent), infection, radiation necrosis and trauma. In the process of chest wall resection and reconstruction, the most important thing is to close the extensive chest wall defect. Many different types of materials have been utilized over the years to replace the rigid chest wall. They can be classified into autogenous, heterogenous and prosthetic materials. In recent years the role of prosthetic materials in the reconstruction of a thoracic defect has earned interest for providing better stability, shortening and simplifying surgical procedures. Traditional materials used for repairing chest wall defects nowadays have several drawbacks. They are not degradable and exist in body for life long, they are inevitably attacked by immunity system and cause immuno-rejective reaction, the sites where they are implanted are likely to infect. So they are not the optimal materials for repairing chest wall defect.With the development of biomaterial and biomedical engineering, the synthetic degradable biomaterials are becoming the hot point of reconstructive surgery. Many animal experiments and clinical research have proved that degradable biomaterials can significantly induce the regeneration of cell and tissue. After having finished the early function of repairing and reconstruction, the degradable biomaterials are decomposed by Phagocyte step by step and replaced by auto-regenerating tissue in vivo. The products of decomposition can be thoroughly absorbed and no harm to human body. The degradable materials made for artificial chest wall substitutes could overcome the drawbacks of conventional materials and meet the clinical need of chest wall reconstructive surgery.The preparation of prosthetic degradable biomaterials used for repairing chest wall defects should be changed from inert, non- degradable materials to bioactive, degradable ones. Synthetic degradable biomaterials made for repairing chest wall defects have not been reported in our country. We are ready to collaborate with Shanghai Jiaotong University to design and prepare prosthetic degradable biomaterials used for repairing chest wall defects. We also establish the animal model of chest wall defects and reconstruction, go into deep study of degradable artificial chest wall. Objective1. Study the biological and physiochemical properties of macromolecule biomaterials, select and integrate perfectly the appropriate artificial chest wall materials2. Prepare the artificial chest wall materials conform to host chest wall tissue in biomechanical properties by composed forming skills3. Study the variation of the mechanical and chemical properties and the tissue reaction of the materials in the process of degradation by biodegradation test in vitro and vivo.4. Evaluate comprehensively the biocompatibility and biological safety of the chest wall materials in vitro and in vivo in accordance with ISO and GB/T of China.5. Establish the animal model of chest wall defects and reconstruction, evaluate thestructure and function of the new born chest wall, provide the practical and theoretical base for the clinical application and dissemination of degradable chest wall prosthesis. Methods1. The design and preparation of artificial chest wall: Polycaprolactone(PCL) has excellent biocompatible and biodegradable properties, slow biodegradation. Besides, PCL has low melting point, just 60 C, so that it can be easily processed and modeled. Having excellent biocompatible and biodegradable properties, chitin fiber also has good mechanical properties. Long chitin fiber reinforced PCL and short chitin fiber reinforced PCL composite were prepared by means of melt blending and modeling. We study the influence of different chitin fiber content (Cf) on the mechanical properties of PCL composite, and select fiber reinforced PCL composite with the optimal fiber content.2. The biodegradation test in vitro and vivo of artificial chest wall materials: Through biodegradation...
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