The European Synchrotron, Avenue des Martyrs 71, Grenoble 38000, France.
Department of Chemistry and iNANO, Aarhus University, Gustav Wieds vej 14, Aarhus 8000, Denmark.
IUCrJ. 2023 Mar 1;10(Pt 2):189-198. doi: 10.1107/S2052252523000866.
Bone is a complex, biological tissue made up primarily of collagen fibrils and biomineral nanoparticles. The importance of hierarchical organization in bone was realized early on, but the actual interplay between structural features and the properties on the nanostructural and crystallographic level is still a matter of intense discussion. Bone is the only mineralized tissue that can be remodeled and, at the start of the formation of new bone during this process, a structure called a cement line is formed on which regular bone grows. Here, the orientational relationship of nanostructural and crystallographic constituents as well as the structural properties of both nanostructural and crystallographic constituents around cement lines and the Haversian system in human lamellar bone are investigated. A combination of small- and wide-angle X-ray scattering tensor tomography is employed together with diffraction tomography and synchrotron computed tomography to generate a multi-modal image of the sample. This work shows that the mineral properties vary as a function of the distance to the Haversian canal and, importantly, shows that the cement line has differing mineral properties from the surrounding lamellar bone, in particular with respect to crystallite size and degree of orientation. Cement lines make up a significant portion of the bone matrix despite their small size, hence the reported findings on an altered mineral structure, together with the spatial modulation around the Haversian canal, have implications for the formation and mechanics of bone.
骨骼是一种复杂的生物组织，主要由胶原纤维和生物矿物质纳米颗粒组成。骨骼的层次结构的重要性很早就被认识到，但结构特征与纳米结构和晶体学水平上的性质之间的实际相互作用仍然是激烈讨论的话题。骨骼是唯一可以重塑的矿化组织，在这个过程中新骨形成的开始时，在其上形成称为水泥线的结构，规则的骨骼在其上生长。在这里，研究了水泥线和哈弗系统周围纳米结构和晶体学成分的取向关系以及纳米结构和晶体学成分的结构性质。小角和广角 X 射线散射张量层析成像与衍射层析成像和同步辐射计算机层析成像相结合，对样品进行了多模态成像。这项工作表明，矿物质性质随距离哈弗管的距离而变化，重要的是，表明水泥线具有不同于周围板层骨的矿物质性质，特别是在晶粒尺寸和取向程度方面。尽管水泥线的尺寸很小，但它们构成了骨基质的重要部分，因此，关于矿物质结构改变的报告结果以及哈弗管周围的空间调制，对骨骼的形成和力学性能都有影响。
