An Automated Step-Wise Micro-Compression Device for 3D Dynamic Image-Guided Failure Assessment of Bone Tissue on a Microstructural Level Using Time-Lapsed Tomography
An Automated Step-Wise Micro-Compression Device for 3D Dynamic Image-Guided Failure Assessment of Bone Tissue on a Microstructural Level Using Time-Lapsed Tomography
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DOI：
10.3389/fmats.2018.00032
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发表时间：
2018-06-05
影响因子：
3.2
通讯作者：
Mueller, Ralph
中科院分区：
文献类型：
--
作者：
Levchuk, Alina;Schneider, Philipp;Mueller, Ralph
微结构骨表型，如骨内管网络，可直接与皮质骨组织的机械失效行为相关。此外，微损伤的高度累积可显著增加骨脆性，因此是机械失效的前兆。在这里，我们讨论了一个自动化的逐步微压缩设备（MCD）的动态图像引导失败评估（DIGFA）的皮质内骨微结构和骨微损伤的发展和验证。该装置被发现是高度准确和精确的定位误差小于1 μ m和力误差小于1.25 N。此外，使用DIGFA和时间推移的计算机断层扫描的第一个生物学研究的结果。简而言之，在逐步压缩中测试来自成熟C57 BL/6（B6）和C3 H/He（C3 H）小鼠的具有中间骨干切口的整个小鼠股骨，并伴随成像直到失效。DIGFA在瑞士光源（SLS）的TOMCAT光束下使用基于同步辐射的计算机断层扫描（SR CT）进行。在实验之后，皮质内孔隙被分离成通道网络、骨细胞陷窝和微裂纹，用于随后的形态测量评价。C3 H较厚的皮质被密集的管道网络穿透，而在B6中仅观察到少量分散的管道。对于B6，在1.45%的局部应变下注意到第一次出现裂纹，而对于C3 H，仅在2.66%的局部应变下发生裂纹萌生。此外，我们能够通过推导微结构孔隙率和微损伤传播之间的相关性，将整个骨力学与局部失效事件联系起来。总之，研究了两种小鼠表型的微裂纹的产生和积累，证明DIGFA结合SR CT是一种合适的技术，用于骨形态和骨折行为的时间推移三维评估，直至细胞水平。
Miorostructural bone phenotypes, such as the intraoortioal canal network, could be directly linked to the mechanical failure behavior of cortical bone tissue In addition, high accumulation of microdamage can significantly increase bone brittleness and thus, is a precursor of mechanical failure. Here, we discuss the development and validation of an automated step-wise micro-compression device (MCD) for dynamic image-guided failure assessment (DIGFA) of intracortical bone microstructure and bone microdamage. The device was found to be highly accurate and precise with positioning errors of less than 1 mu m and force errors of less than 1.25 N. In addition, the results of a first biological study using DIGFA and time-lapsed computed tomography are presented. In short, whole mouse femora from mature C57BL/6 (B6) and C3H/He (C3H) mice with mid-diaphyseal notches were tested in step-wise compression and concomitantly imaged until failure. DIGFA was performed at the TOMCAT beamlme of the Swiss Light Source (SLS) using synchrotron radiation-based computed tomography (SR CT). Following the experiment, intracortical porosity was separated into the canal network, osteocyte lacunae, and microcracks for subsequent morphometric evaluation. The thicker cortex of C3H was penetrated by a dense canal network, whereas in B6 only a few scattered canals were observed. For B6, the first occurrence of crack was noted at 1.45% local strain, while for C3H, crack initiation took place only at 2.66% local strain. In addition, we were able to relate whole bone mechanics to local failure events by deriving correlations between mi.rostruetural porosity and microdamage propagation. In conclusion, initiation and accumulation of microcracks were investigated for two mouse phenotypes demonstrating that DIGFA in combination with SR CT is a suitable technique for time-lapsed three-dimensional assessment of bone morphology and bone fracture behavior down to the cellular level.