Bone: ultrastructure, mineralogy and chemistry

骨骼是构成我们骨骼的材料，是一种精心设计的材料，由等量的两种成分组成：矿物质和胶原蛋白。这种矿物质由钙盐和磷酸盐的微小晶体组成，这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，是我们体内最丰富的蛋白质，也存在于皮肤和肌腱中。骨骼中的胶原蛋白形成了纤细的“原纤维”，这些纤维捆绑在一起，沿着我们长骨的轴线排列，但是矿物质在哪里呢？以前的研究人员认为它主要在胶原蛋白内部，填充胶原蛋白端到端分子之间的小间隙。然而，我们的研究表明，这种观点是错误的，几乎所有的骨矿物质都是以细长的支柱的形式存在的，这些支柱平行于胶原纤维，并像桶周围的棍棒一样堆叠在它们周围。这些支柱本身是由更小的晶体片组成的，这些晶体片显然是粘在一起制成支柱的。我的研究将旨在提高我们对这种新发现的结构的理解，并了解它是如何形成的。我将利用强大的电子显微镜，使我们能够可视化构成骨骼的最小结构。使用化学试剂，我们将把骨头分开，并提取整个矿物支柱，这样我们就可以研究它们的形式以及它们如何有助于骨骼的强度。我还将与麦克马斯特的生物医学工程师合作，他们正在确定如何通过在显微镜下研究活骨与金属接触时发生的情况来制造最好的金属植入物。* 虽然大多数陆地动物的骨头在亚显微尺度下看起来非常相似，但鱼的骨头看起来却奇怪地不同。我将在电子显微镜下研究鱼骨，并试图了解陆地动物是如何从鱼进化而来的，发展出一种更适合支撑它们抵抗重力的不同类型的骨头。 * 通过对人类和动物骨骼构造的知识做出贡献，这项研究可以导致医学科学家开发骨骼疾病的新疗法。我们的研究也将有助于改善骨植入物和骨折愈合的结果。这是许多加拿大人的主要健康问题。 ********

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.***My research will be targeted on improving our understanding of this newly discovered structure, and learning how it is formed. I will make use of powerful electron microscopes that allow us to visualize the smallest structures that make up bone. Using chemical reagents, we will take apart bone and extract the mineral struts whole, so that we can study their form and how they contribute to the strength of bone. I will also collaborate with biomedical engineers at McMaster who are determining how to create the best metal implants to be inserted into bones, by studying under the microscope what happens where the living bone meets metal. ***Even though most bone from land animals looks quite similar when viewed at this submicroscopic scale, bone from fish looks oddly different. I will study fish bone under the electron microscope and try to learn how land animals, evolved from fish, developed a different kind of bone that was better suited to supporting them against the force of gravity. ***By contributing to our knowledge of how bone is constructed in humans and animals, this research can lead to the development by medical scientists of new therapies for diseases of bone. Our studies will also aid in improving the outcome of bone implants and fracture healing. These represent major health concerns for many Canadians. ********