Assessment of composition and anisotropic elastic properties of secondary osteon lamellae
Assessment of composition and anisotropic elastic properties of secondary osteon lamellae
复制标题
DOI：
10.1016/j.jbiomech.2005.07.009
复制
发表时间：
2006-01-01
影响因子：
2.4
通讯作者：
Raum, Kay
中科院分区：
文献类型：
--
作者：
Hofmann, Tobias;Heyroth, Frank;Raum, Kay
单个骨单位板的弹性特性的测量一直是骨力学领域中亟待解决的问题之一。利用匹配拉曼光谱、声学显微镜和纳米压痕技术研究了次级骨单位中单个骨板的结构、化学组成和各向异性弹性，并获得了人股骨切片的声阻抗图像（911 MHz）和二维拉曼光谱。以相对于股骨长轴的各种观察角度0制备样本。纳米压痕提供了必要的声学和光谱拉曼图像的空间融合的弹性模量和地标的本地估计。将代表矿物和胶原空间分布的磷酸盐v（1）（961 cm（-1））和酰胺1（1665 cm（-1））谱带图像与声图像融合，将声阻抗与压痕弹性模量E-IT（R-2 = 0.61）进行相关分析。这两个参数都对弹性组织各向异性敏感。在垂直于股骨长轴的方向上获得最低值。声学图像表现出交替的高阻抗值和低阻抗值的特征双峰层状图案。由于这种起伏与拉曼图像中磷酸盐v（1）带强度的变化无关，因此它归因于层状取向的变化。经过阈值分割和转换为弹性模量的取向和横观各向同性的弹性常数推导出的表观薄和厚层的个人合奏。我们的研究结果表明，该模型代表了有效的各向异性性能的不对称扭曲胶合板结构制成的横向各向同性fibrills.This是第一份报告，实验证明的能力，声学显微镜映射组织弹性在两个维度与微米分辨率。与拉曼显微光谱的结合为在超微组织水平上研究骨和矿物质代谢及其与机械功能的关系提供了一种独特的方法。(c)2005爱思唯尔有限公司保留所有权利。
Measurement of the elastic properties of single osteon lamellae is still one of the most demanding tasks in bone mechanics to be solved. By means of site-matched Raman microspectroscopy, acoustic microscopy and nanoindentation the structure, chemical composition and anisotropic elasticity of individual lamellae in secondary osteons were investigated.Acoustic impedance images (911-MHz) and two-dimensional Raman spectra were acquired in sections of human femoral bone. The samples were prepared with orientations at various observation angles 0 relative to the femoral long axis. Nano-indentations provided local estimations of the elastic modulus and landmarks necessary for spatial fusion of the acoustic and spectral Raman images. Phosphate v(1) (961 cm(-1)) and amide 1 (1665 cm(-1)) band images representing spatial distributions of mineral and collagen were fused with the acoustic images.Acoustic impedance was correlated with the indentation elastic modulus E-IT (R-2 = 0.61). Both parameters are sensitive to elastic tissue anisotropy. The lowest values' were obtained in the direction perpendicular to the femoral long axis. Acoustic images exhibit a characteristic bimodal lamellar pattern of alternating high and low impedance values. Since this undulation was not associated with a variation of the phosphate v(1)-band intensity in the Raman images, it was attributed to variations of the lamellar orientation. After threshold segmentation and conversion to elastic modulus the orientation and transverse isotropic elastic constants were derived for individual ensembles of apparent thin and thick lamellae. Our results suggest that this model represents the effective anisotropic properties of an asymmetric twisted plywood structure made of transverse isotropic fibrils.This is the first report that proves experimentally the ability of acoustic microscopy to map tissue elasticity in two dimensions with micrometer resolution. The combination with Raman micro spectroscopy provides a unique way to study bone and mineral metabolism and the relation with mechanical function at the ultrastructural tissue level. (c) 2005 Elsevier Ltd. All rights reserved.