Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
Musculoskeletal Integrity Program, Hospital for Special Surgery, New York, NY, 10021, USA.
Sci Rep. 2018 Jan 19;8(1):1191. doi: 10.1038/s41598-018-19253-w.
Tough natural nanocomposites like bone, nacre and sea sponges contain within their hierarchy, a mineral (phosphate, silicate or carbonate) phase that interacts with an organic phase. In bone, the role of mineral ultrastructure (organization, morphology, composition) is crucial to the mechanical and biological properties of the tissue. Better understanding of mineral interaction with the organic matrix, in particular non-collagenous proteins, osteocalcin (OC) and osteopontin (OPN), can lead to better design of biomimetic materials. Using small angle x-ray scattering (SAXS) and wavelength dispersive spectroscopy (WDS) on single (OC and OPN) and double (OC-OPN) genetic knockout mice bones, we demonstrate that both osteocalcin and osteopontin have specific roles in the biomolecular regulation of mineral in bone and together they are major determinants of the quality of bone mineral. Specifically, for the first time, we show that proteins osteocalcin and osteopontin regulate bone mineral crystal size and organization in a codependent manner, while they independently determine crystal shape. We found that OC is more dominant in the regulation of the physical properties of bone mineral, while OPN is more dominant in the regulation of the mineral composition.
坚韧的天然纳米复合材料，如骨骼、珍珠母和海绵，在其层次结构中包含一个与有机相相互作用的矿物质（磷酸盐、硅酸盐或碳酸盐）相。在骨骼中，矿物质超微结构（组织、形态、组成）的作用对组织的机械和生物特性至关重要。更好地了解矿物质与有机基质的相互作用，特别是非胶原蛋白、骨钙素（OC）和骨桥蛋白（OPN），可以导致更好的仿生材料设计。我们使用单（OC 和 OPN）和双（OC-OPN）基因敲除小鼠骨骼的小角 X 射线散射（SAXS）和波长色散光谱（WDS），证明骨钙素和骨桥蛋白在骨骼矿物质的生物分子调节中都具有特定作用，并且它们共同决定了骨矿物质的质量。具体来说，我们首次表明，蛋白质骨钙素和骨桥蛋白以相互依赖的方式调节骨矿物质晶体的大小和组织，而它们独立地决定晶体形状。我们发现，OC 在调节骨矿物质的物理性质方面更为重要，而 OPN 在调节矿物质组成方面更为重要。
