双层仿骨膜材料的构建及其诱导骨组织修复的研究

The present artificial bone repair materials still had some problems, including lacking of bonding interface with autogenous bone and delayed healing, which was mainly resulted from the failure of blood transporting. Actually, the bone periosteum existed on the bone surface plays important roles in both supplying blood to the bone and promoting the formation of new bone, which was the major reason for the success of autograft. Therefore, constructing materials with the similar structure and properties to autologous periosteum has the vital significance to realize the rapid bone repair. According to the structure and function of the periosteum, we aim to design bi-layer multifunctional biomimetic periosteum materials to be used in rapid bone repair by choosing biocompatible silk fibroin (SF) as the substrate material. Electrospinning was used as the main fabrication technology. The bi-layer biomimetic periosteum materials were composed of outer and inner layer, which loaded vascular endothelial growth factor (VEGF) and hydroxyapatite (HA), respectively. By regulating the processing methods and key parameters in the fabrication process, the bi-layer multifunctional biomimetic periosteum materials with similar microstructure and mechanical properties to autologous periosteum was realized. Furthermore, the relationship between the factors, such as SF secondary structure, drug loading content and loading method, and the controlled release of VEGF and HA was elucidated by studying the drug release kinetics of the materials. This study will provide theoretical guidance to realize the multifunction of vascularization and inducing the bone regeneration and their synergistic effect. Finally, the biomimetic periosteum with the function of rapidly inducing the bone repair will be obtained.

当前人工骨材料对于骨组织的修复还存在难以形成骨性结合、骨愈合延迟等问题，其主要原因在于缺乏血供。骨膜存在于骨表面，既能为骨生长输送血液又能促进新骨生成，成为自体骨移植临床效果最佳的重要原因，但其来源少、取材难。因此研发出与自体骨膜具有相似结构与功能的材料，对于实现快速骨组织修复具有重要意义。本项目拟模仿骨膜的双层结构及其功能特点，以生物相容性好的丝素蛋白为基材，静电纺丝技术为主要手段，制备出内外层分别负载羟基磷灰石及血管内皮生长因子的双层仿骨膜材料，通过调控关键工艺及参数，使其微观结构及力学性能与自体骨膜相似，然后通过药物释放动力学研究，阐明丝素二级结构、负载量、负载方式等因素对羟基磷灰石及血管内皮生长因子的控制释放规律，为实现仿骨膜材料的血管化与促骨再生功能及其协同作用提供理论指导，最终构建出能快速诱导骨组织修复的仿骨膜材料。

本项目旨在研发出与自体骨膜具有相似结构与功能的材料，用于快速骨组织修复。以丝素蛋白（SF）为基材，利用静电纺丝技术的优点，模拟自体骨膜的双层微结构，制备出了双层仿骨膜材料，微观呈纤维网状结构。制备所得到的SF纤维直径在1μm左右；双层SF膜的断裂强度可达6.64MPa，断裂伸长率在10.76%左右，随着HA的加入，SF膜的力学性能有所提高，VEGF的加入对力学性能影响不大；双层SF膜在蛋白酶中降解2周，质量损失在26%左右；双层SF膜的吸水率可达60%左右；双层SF膜的2周VEGF释放量在19.6%左右；此外，该材料能促进血管内皮细胞和成骨细胞的生长，短期内可在动物体内观察到微血管的形成，预示了促骨愈合能力。本项目按照计划完成了既定的研究内容，达到了预期的研究目标；同时在原有研究内容基础上，考察了SF及SF/ HAc（透明质酸）复合材料所制备的膜的结构及性能之间的关系，并探讨丝素蛋白作为VEGF缓释载体的应用前景。本项目累计发表标注受本项目资助的国内统计源期刊1篇和SCI2篇，申请国家发明专利4项；与本项目相关的授权专利2项。本项目的实施既能为快速骨缺损修复提供可用的修复材料，加快患者伤骨的愈合速度、缩短疗程，又能带动丝素在生物医学产业中的发展。