Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China.
Collaboration and Innovation Center of Tissue Repair Material Engineering Technology, College of Life Science, China West Normal University, Nanchong 637009, China.
Int J Mol Sci. 2022 Sep 28;23(19):11459. doi: 10.3390/ijms231911459.
Macroporous characteristics have been shown to play a key role in the osteoinductivity of hydroxyapatite ceramics, but the physics underlying the new bone formation and distribution in such scaffolds still remain elusive. The work here has emphasized the osteoinductive capacity of porous hydroxyapatite scaffolds containing different macroporous sizes (200-400 μm, 1200-1500 μm) and geometries (star shape, spherical shape). The assumption is that both the size and shape of a macropore structure may affect the microfluidic pathways in the scaffolds, which results in the different bone formations and distribution. Herein, a mathematical model and an animal experiment were proposed to support this hypothesis. The results showed that the porous scaffolds with the spherical macropores and large pore sizes (1200-1500 μm) had higher new bone production and more uniform new bone distribution than others. A finite element analysis suggested that the macropore shape affected the distribution of the medium-high velocity flow field, while the macropore size effected microfluid speed and the value of the shear stress in the scaffolds. Additionally, the result of scaffolds implanted into the dorsal muscle having a higher new bone mass than the abdominal cavity suggested that the mechanical load of the host tissue could play a key role in the microfluidic pathway mechanism. All these findings suggested that the osteoinduction of these scaffolds depends on both the microfluid velocity and shear stress generated by the macropore size and shape. This study, therefore, provides new insights into the inherent osteoinductive mechanisms of bioceramics, and may offer clues toward a rational design of bioceramic scaffolds with improved osteoinductivity.
大孔特征被证明在羟基磷灰石陶瓷的成骨性中起着关键作用,但新骨形成和分布在这种支架中的物理机制仍难以捉摸。本工作强调了具有不同大孔尺寸(200-400μm、1200-1500μm)和形状(星形、球形)的多孔羟基磷灰石支架的成骨能力。假设大孔结构的大小和形状都可能影响支架中的微流通道,从而导致不同的骨形成和分布。在此,提出了一个数学模型和动物实验来支持这一假设。结果表明,具有球形大孔和较大孔径(1200-1500μm)的多孔支架具有更高的新骨生成量和更均匀的新骨分布。有限元分析表明,大孔形状影响中高速流场的分布,而大孔尺寸影响微流体速度和支架中的剪切应力值。此外,支架植入背部肌肉的新骨量高于腹腔的结果表明,宿主组织的机械负荷可能在微流通道机制中发挥关键作用。所有这些发现表明,这些支架的成骨作用取决于大孔尺寸和形状产生的微流体速度和剪切应力。因此,本研究为生物陶瓷的固有成骨机制提供了新的见解,并可能为设计具有改善成骨能力的生物陶瓷支架提供线索。