Ultrastructural changes accompanying the mechanical deformation of bone tissue: A Raman imaging study
Ultrastructural changes accompanying the mechanical deformation of bone tissue: A Raman imaging study
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DOI：
10.1007/s00223-002-1039-0
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发表时间：
2003-02-01
影响因子：
4.2
通讯作者：
Kohn, DH
中科院分区：
文献类型：
--
作者：
Carden, A;Rajachar, RM;Kohn, DH
已知拉曼光谱和成像是用于分析骨、确定蛋白质二级结构和研究晶体材料组成的有价值的工具。我们已经利用所有这些属性来研究机械载荷和由此产生的变形如何影响骨超微结构，解决骨光谱改变的假设，在有机和无机区域，响应于机械载荷/变形。使用圆柱形压头，我们永久变形的牛皮质骨标本和研究的超微结构中和周围的变形地区，使用高光谱拉曼成像结合多元分析技术。使用扫描电子显微镜进一步检查压痕形态。在凹痕边缘处拍摄的拉曼图像显示酰胺III带的低频分量和酰胺I带的高频分量增加。这些变化表明由于压头穿过骨施加的剪切力导致胶原交联断裂。然而，在纤维本身内没有看到交联断裂的证据，表明在该区域仅发生有机基质的压缩。我们还提出了什么是可能的压力引起的结构转变发生在骨矿物质内的凹痕，如所示的外观额外的矿物因素在拉曼图像数据从缩进区域的证据。这些结果提供了新的见解的机制和原因，骨失败的超微结构水平。
Raman spectroscopy and imaging are known to be valuable tools for the analysis of bone, the determination of protein secondary structure, and the study of the composition of crystalline materials. We have utilized all of these attributes to examine how mechanical loading and the resulting deformation affects bone ultrastructure, addressing the hypothesis that bone spectra are altered, in both the organic and inorganic regions, in response to mechanical loading/deformation. Using a cylindrical indenter, we have permanently deformed bovine cortical bone specimens and investigated the ultrastructure in and around the deformed areas using hyperspectral Raman imaging coupled with multivariate analysis techniques. Indent morphology was further examined using scanning electron microscopy. Raman images taken at the edge of the indents show increases in the low-frequency component of the amide III band and high-frequency component of the amide I band. These changes are indicative of the rupture of collagen crosslinks due to shear forces exerted by the indenter passing through the bone. However, within the indent itself no evidence was seen of crosslink rupture, indicating that only compression of the organic matrix takes place in this region. We also present evidence of what is possibly a pressure-induced structural transformation occurring in the bone mineral within the indents, as indicated by the appearance of additional mineral factors in Raman image data from indented areas. These results give new insight into the mechanisms and causes of bone failure at the ultrastructural level.