纳米羟基磷灰石/胶原骨修复材料

目的：制备纳米相羟基磷灰石／胶原（nano-HAp/Collagen,NHAC)复合材料,并检测骨修复性能。方法：采用仿生方法制备NHAC复合材料。结果：NHAC复合材料成分与微结构具有同天然骨类似的某些特征。复合材料的矿物含量约为50％,矿物相为含有碳酸根的羟基磷灰石,结晶度低,晶粒尺寸为纳米量级,矿物相均匀沉积在I型胶原蛋白基质上,NHAC复合材料的力学性能表现为各向同性,其显微硬度可以达到骨皮质显微硬度的下限,用颗粒型NHAC材料压制成的致密种植体植入骨髓腔后,界面层可发生溶解－再沉积的动态快速更新过程,巨噬细胞可在种植体表面或深入种植体内部通过吞噬和胞外降解方式吸收种植体材料,种植体表面及内部被吸收后,伴随有新骨的沉积,这一现象类似骨组织的重塑过程,可使NHAC种植体整合入活体骨的新陈代谢中并最终为自体现有组织所取代。结论：NHAC是生物活性材料,种植体与最组织可形成界面化学键合。

Nano-hydroxyapatite/collagen composite for bone repair

OBJECTIVE: To develop nano-hydroxyapatite/collagen (NHAC) composite and test its ability in bone repairing. METHODS: NHAC composite was developed by biomimetic method. RESULTS: The composite showed some features of natural bone in both composition and microstructure. The minerals could contribute to 50% by weight of the composites in sheet form. The inorganic phase in the composite was carbonate-substituted hydroxyapatite (HA) with low crystallinity and nanometer size. HA precipitates were uniformly distributed on the type I collagen matrix without preferential orientation. The composite exhibited an isotropic mechanical behavior. However, the resistance of the composite to localized pressure could reach the lower limit of that of femur compacta. The tissue response to the NHAC composite implanted in marrow cavity was investigated. Knoop micro-hardness test was performed to compare the mechanical behavior of the composite and bone. At the interface of the implant and marrow tissue, solution-mediated dissolution and macrophage-mediated resorption led to the degradation of the composite, followed by interfacial bone formation by osteoblasts. The process of implant degradation and bone substitution was reminiscent of bone remodeling. CONCLUSION: The composite can be incorporated into bone metabolism instead of being a permanent implant.