Fluid shear stress (FSS) is regarded as a predominant stimulus to bone cells and matrix under physiological conditions. The influence of FSS on mineralization of collagen is explored by exposure to an environment of constant FSS values less than 2.0 Pa. At the designated time points, the apatite/collagen composites were characterized by X-ray diffraction, calcium/phosphorus assay, differential scanning calorimetry, transmission electron microscopy, and selected area electron diffraction. The results show that FSS within a certain range, especially within 1.5 Pa, has a positive effect on collagen mineralization, as illustrated by the enhanced degree of collagen self-assembly, accelerated speed of amorphous calcium phosphate (ACP) formation and transition, and well-organized apatite structure and orientation. Under the condition of FSS, the size of ACP is also well controlled, and the minerals disperse inside collagen fibrils; this leads to intrafibrillar mineralization. These findings are helpful for understanding the mechanism of mineralization in natural bone tissue and deepen the knowledge of biomechanics of this process.

中文翻译：

---

胶原蛋白原纤维的剪切介导的骨磷灰石定向矿化

在生理条件下，流体剪切应力（FSS）被认为是对骨细胞和基质的主要刺激。通过暴露于恒定FSS值小于2.0 Pa的环境中，探索了FSS对胶​​原矿化的影响。在指定的时间点，通过X射线衍射，钙/磷测定，差示扫描表征了磷灰石/胶原蛋白复合物的特征。量热法，透射电子显微镜和选定区域电子衍射。结果表明，一定范围内的FSS，尤其是1.5 Pa内的FSS，对胶原蛋白矿化有积极作用，这可以通过增强胶原蛋白自组装程度，加快非晶态磷酸钙（ACP）形成和过渡的速度以及良好的状态来证明。 -组织的磷灰石结构和取向。在FSS的条件下，ACP的大小也得到了很好的控制，并且矿物质分散在胶原纤维内部。这导致原纤维内矿化。这些发现有助于理解天然骨组织中矿化的机制，并加深了该过程的生物力学知识。