胫骨羟基磷灰石片交叉微结构研究

Microstructure of Hydroxyapatite Sheets in Shankbone

利用扫描电镜对胫骨的微结构进行了观察,结果显示胫骨是一种由羟基磷灰石和胶原蛋白组成的生物陶瓷复合材料。羟基磷灰石平行于骨的表面以层状形式排列,胶原蛋白分布在羟基磷灰石层中起粘合的作用,这使得骨在断裂时裂纹在羟基磷灰石层间折拐分叉,使骨具有高的断裂韧性。观察也显示,羟基磷灰石层由长而薄、与所在层垂直的羟基磷灰石片所组成。进一步地观察发现,不同羟基磷灰石层中的羟基磷灰石片具有不同的方向,构成一种羟基磷灰石片交叉排列的微结构。通过模型分析,比较研究了羟基磷灰石片交叉排列微结构与平行排列微结构的最大拔出力,结果表明,交叉排列微结构的最大拔出力大于平行排列微结构的最大拔出力。研究结果对仿骨陶瓷复合材料设计具有指导意义。

Observation of a shankbone under Scanning Electronic Microscope （SEM） finds the bone is a kind of natural bioceramic composite that consists of the hydroxyapatite layers and collagen protein. The hydroxyapatite layers are parallel to the surface of the bone, which makes the crack spread in zigzag and increases the fracture toughness of the bone. The observation also show that the hydroxyapatite layers consists of the hydroxyapatite sheets with different orientations and consisting of a crossed structure. The maximum pullout force in the crossed structure is investigated and compared with a parallel structure. The result show that the maximum pullout force of the crossed structure is remarkably increased than that in the parallel structures. The crossed structure also improved the fracture toughness of the bones.