中文摘要：

创伤、感染、肿瘤和先天畸形等均会造成骨组织的缺损,当缺损超过临界尺寸时,骨组织无法完成自我修复,应用生物材料引导骨组织的再生从而修复缺损组织是极为重要的治疗策略,而骨形成速度慢则是当前引导骨再生支架面临的难点之一.氧化铁磁性纳米颗粒（γ-Fe2O3-NP）和纳米羟基磷灰石（nHA）与消旋聚乳酸（PDLLA）以不同比例共混,利用高压静电纺丝技术制备具有纳米纤维网络结构的复合材料薄膜.应用振荡样品磁强计研究复合材料的磁学性质与氧化铁磁性纳米颗粒含量之间的关系,通过扫描电镜观察薄膜材料的微观结构特征.选取12只健康雄性成年新西兰大白兔,在横突骨组织离断模型上,采用CT成像技术,研究术后10、30、50 d时复合材料植入组、复合材料植入加磁场组以及离断无治疗对照组的骨组织再生与缺损修复效果;此外,在术后20 d采集每组中2只动物的植入部位组织进行病理观察.研究结果显示,复合材料具有超顺磁响应性质,且随材料中氧化铁纳米颗粒比例的提高而增强;该复合材料可以在外加磁场的作用下,加速引导离断缺损部位的骨组织再生.

英文摘要：

Bone tissue cannot accomplish self-healing in critical size bone defects resulted from trauma, infection, tumor and congenital malformation. Using biomaterials that induce bone tissue regeneration to repair bone defects is an extremely important therapeutic strategy. However, slow bone formation is one of the difficulties in biomaterial-induced bone regeneration. In this work, a magnetic responsive nanofibrous composite film was fabricated with poly lactide acid （PLA）, hydroxyapatite nanoparticles （nHA） and γ/-Fe2O3 nanoparticles （γ-Fe2O3-NP） using electrospinning technique. The film was folded into a 3D scaffold that suitable for implantation in bone defect sites. The relationship between magnetic properties of composite materials and the percentage of iron oxide magnetic nanoparticles was investigated using vibrating samplemagnetometer （VSM）. The microstructure of films was observed by scanning electron microscopy （SEM）. The effect of magnetic responsive composites on inducing bone repair and regeneration in situ under an applied magnetic field was evaluated in bone transverse process disartitulation model of 12 healthy male New Zealand rabbits after 10,30,50 days implantation. Results indicate that the composite display a strong paramagnetic property and show a positive correlation with the proportion of iron oxide nanoparticles. In an applied magnetic field, the bone tissue regeneration in the disarticulation sites was accelerated with the guidance of the composite scaffold.