Static and time-dependent mechanical response of organic matrix of bone.
Static and time-dependent mechanical response of organic matrix of bone.
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DOI：
10.1016/j.jmbbm.2018.12.031
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发表时间：
2019-03
影响因子：
3.9
通讯作者：
Kumar N
中科院分区：
文献类型：
--
作者：
Saini K;Discher D;Kumar N
骨的机械强度来自于纤维外和纤维内的胶原纤维(主要是I型)的复杂排列，以及羟基磷灰石(HAP)矿物晶体的强化。这项研究展示了一种新的方法，通过脱矿获得有机骨基质，并使用静态和动态压痕技术在小长度尺度上对其进行机械表征。本研究采用的样品表面制备方法保持了脱钙骨样品的表面完整性，使样品表面的粗糙度(RMS)约为14 nm(原子力显微镜(AFM)证实的平均面积超过1×1微米2)。通过能量色散X射线光谱分析(EDX)进行的元素组成分析(探测深度可达2微米)证实，在使用EDTA脱矿的过程中，骨样中的羟基磷灰石矿物被完全去除，而二次谐波产生(SHG)成像显示，胶原分子组装没有受到影响。用准静态和动态压痕(频率为30 Hz)测得的有机基质的模量值分别为∼2.6 GPa和4.5 Gpa，说明了加载速率对估算的力学性能的影响。有趣的是，当压痕深度与表面粗糙度之比大于∼5：1时，所测得的有机基质的材料性能依赖于从少量胶原纤维到下一层次即胶原纤维的压痕深度的增加，最高可达∼500 nm。这些发现对于准确确定矿化组织的有机基质的弹性和粘弹性响应是非常有用的，这些应用包括组织工程、生物仿生等。
Bone derives its mechanical strength from the complex arrangement of collagen fibrils (type-I primarily) reinforced with hydroxy-apatite (HAp) mineral crystals in extra- and intra-fibrillar compartments. This study demonstrates a novel approach to obtain organic matrix of bone through its demineralization as well as mechanically characterize it at small length scales using static and dynamic indentation techniques. Sample surface preparation protocol used in the present work maintained the surface integrity of demineralized bone samples which resulted sample surface of roughness (RMS) magnitude of approximately 14 nm (averaged over 1×1 µm2 area duly verified by atomic force microscope (AFM)). Elemental composition analysis via energy dispersive X-ray spectroscopy (EDX) (for probed depth upto 2 µm) confirmed the complete removal of HAp mineral from bone samples during their demineralization using EDTA leaving collagen molecule assemblies unaffected as represented by Second Harmonic Generation (SHG) imaging. The modulus magnitudes of organic matrix obtained using from quasistatic as well as dynamic indentations (at constant frequency of 30 Hz) as ∼2.6 GPa and 4.5 GPa respectively, demonstrated the influence of loading rate on the estimated mechanical properties. For indentation depth to surface roughness ratio greater than ∼5:1, interestingly, measured material properties of organic matrix were found to depend on increasing magnitude of indentation depth of up to ∼500 nm value which probed from few collagen fibrils to next level of hierarchy i.e. collagen fibers. These findings are very useful to accurately determine the elastic and visco-elastic response of organic matrices of mineralized tissues for various applications including tissue engineering, bio-mimetics, etc.
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影响因子：
2.7
作者：
Herbert, E. G.;Oliver, W. C.;Pharr, G. M.
通讯作者：
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影响因子：
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Wagner, William R.
影响因子：
5.6
作者：
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通讯作者：
MOOK, HA