Bone: ultrastructure, mineralogy and chemistry

骨是构成我们骨骼的材料，它是一种由等量的两种成分组成的精细工程材料：矿物质和胶原蛋白。这种矿物由钙和磷酸盐的微小晶体组成，这两种盐是我们身体中的两种基本化学物质。胶原蛋白是一种蛋白质，是我们身体中含量最丰富的蛋白质，也存在于皮肤和肌腱中。骨胶原形成细小的“纤维”，它们被捆绑在一起，沿着我们长骨的轴线排列，但矿物质在哪里呢？之前的研究人员认为，它主要在胶原蛋白内部，填补了胶原蛋白端到端分子之间的微小间隙。然而，我们的研究表明，这种观点是错误的，骨骼中几乎所有的矿物质都是与胶原纤维平行的细长支柱，并像木桶周围的棍棒一样堆积在它们周围。这些支柱本身是由更小的水晶片组成的，显然是粘合在一起形成的支柱。

Bone, the material out of which our bones are constructed, is a finely engineered material made of equal amounts of two components: mineral and collagen. The mineral consists of tiny crystals of a salt of calcium and phosphate, two of the essential chemicals in our body. Collagen is a protein, the most abundant one in our body, also found in skin and tendons. The collagen of bone forms wispy “fibrils” that are bundled together and lined up along the axes of our long bones, but where is the mineral? Previous researchers thought that it was mainly inside the collagen, filling little gaps between end-to-end molecules of collagen. Our research has shown, however, that this view is mistaken, and that almost all the mineral in bone is in the form of slender struts that run parallel to the collagen fibrils and are stacked around them like staves around a barrel. These struts are themselves composed of even smaller crystal flakes that are apparently glued together to make the struts.