图1. 天然骨组织的层次结构模式图和人股骨骨干部皮质骨扫描电镜照片^[1,11]

Fig. 1. Schematic diagram of bone hierarchical structural organization (up part) and scanning electron microscope images (bottom part) of the cortical bone specimens located at human femoral diaphysis^[1,11]
In bone tissue, macroscale arrangements involve both compact/ cortical bone at the surface and spongy/trabecular bone in the interior. Compact bone is composed of osteons and Haversian canals, which surrounded by blood vessels. Osteons have a lamellar structure, with individual lamella consisting of fibers arranged in geometrical patterns. The fibers comprise several mineralized collagen fibrils, composed of collagen protein molecules formed from three chains of amino acids and nanocrystals of hydroxyapatite, and linked by an organic phase to form fibril arrays