冻干同种异体髂骨作为支架材料的性能研究

Study on properties of freeze-dried iliac crest bone allograft as scaffold material

目的研究冻干同种异体髂骨块支架材料的微观结构及生物力学特点。方法参考美国组织库协会标准,进行髂骨块采取、脱细胞、脱脂、脱蛋白、消毒、保存。分别将纤维蛋白胶、利福平负压灌注入骨块孔隙内;大体观察冻干同种异体髂骨块、载利福平髂骨块的结构特征,扫描电镜观察孔径、孔隙连通、利福平晶体分布情况,液体置换法测定孔隙率和密度,弯曲试验、扭转试验、压缩试验评价其力学性能。结果冻干同种异体髂骨支架材料呈乳白色,为三面薄层皮质骨及中间松质骨组成的"夹心饼结构",具有骨组织天然三维网状孔隙,孔隙内洁净,相互连通,利福平晶体被纤维蛋白胶均匀地固定于骨块表面和内部;冻干同种异体髂骨块密度(0.35±0.03)g/ml,孔隙率(67.23±9.12)%,孔径(395.36±37.02)μm,抗扭强度(5.96±1.53)MPa,抗压强度(9.94±0.73)MPa,弹性模量(376.14±27.32)MPa,抗弯强度(15.70±2.35)MPa。结论冻干髂骨块具有天然生理性孔隙,生物力学性能良好,具有广阔的开发前景。

Objective To study the microstructure and biomechanical properties of freeze-dried iliac crest bone allograft with regard to its potential applications as bone substitute, scaffold for bone tissue engineering and in drag delivery system. Methods Procurement, processing, sterilization and conservation of the iliac crest allograft scaffold were all performed according to the guidelines of the American Association of Tissue Banks. The graft segments were impregnated with Fibrin glue and rifampicin using negative pressure technique. Its physical characteristics were observed including eolour, texture and porosities. The pore diameter and microstructure were investigated with scanning electron microscope. Its porosity and density were measured by liquid displacement. Biomechanical tests were conducted in axial compression, lateral bending and rotation modes. Results The freeze-dried iliac crest bone allograft was ivory white, clean and porous, presenting sand- wich structure in tricortical and cancellous bone. The rifampiein crystal was cemented in the pore by fibrin. Its mean density , porosity and pore diameter was （0.35 ±0.03 ） g/ml, （67.23 ± 9.12） %, （395.36±37.02） μm, respectively. The mean anti-rotation strength, compressive strength, elastic modulus, buckling strength was （5.96±1.53）,（9.94±0.73）,（376.14±27.32）,（15.70±2.35）MPa, respectively. Conclusion The freeze-dried iliae crest bone allograft is a natural porous bone substitute with satisfying biomechanical strength, showing a great potential for further exploration.