Mapping the Young's modulus distribution of the human tympanic membrane by microindentation
Mapping the Young's modulus distribution of the human tympanic membrane by microindentation
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DOI：
10.1016/j.heares.2019.02.009
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发表时间：
2019-07-01
期刊：
影响因子：
2.8
通讯作者：
Lu, Hongbing
中科院分区：
文献类型：
--
作者：
Luo, Huiyang;Wang, Fang;Lu, Hongbing
人鼓膜（TM或鼓膜）主要由径向和周向取向的胶原纤维层以及外侧和内侧表面的表皮和粘膜层组成。TM的机械性能取决于胶原纤维的微观结构，其随位置而变化，导致杨氏模量的空间变化。在这项研究中，杨氏模量的人TM测量使用微压痕。使用10 μ m直径的球形纳米压头尖端在外侧和内侧表面的不同位置处对TM进行抛光。通过粘弹性接触分析，从单轴松弛模量确定TM在恒定应变速率下的稳态面外（通过厚度）杨氏模量。报告了外侧面和内侧面上整个TM张力部的杨氏模量的测量空间分布。使用正态分位数-分位数（Q-Q）图对四个TM象限的杨氏模量进行统计分析。所获得的S形曲线指示Q-Q图中的双峰高斯分布。杨氏模量的空间分布通过极坐标中的双变量高斯函数在外侧和内侧表面的整个TM上建模。结果表明，前上象限具有最小值的杨氏模量。在外侧和内侧表面的杨氏模量的空间分布中观察到差异。对于内侧表面，杨氏模量主要沿着径向变化，遵循从小-大-小的趋势，从脐部发出。对于外侧面，前上象限处的模量最小，沿径向沿着逐渐减小。本文中提出的定量结果将有助于改善未来的仿真模型，通过使用空间依赖性的杨氏模量在整个TM的中耳。(C)2019爱思唯尔B.V.保留所有权利。
The human tympanic membrane (TM, or eardrum) is composed primarily of layers of collagen fibers oriented in the radial and circumferential directions, as well as epidermal and mucosal layers at the lateral and medial surfaces. The mechanical properties of the TM depend on the microstructures of the collagen fibers, which vary with location, resulting in a spatial variation of Young's modulus. In this study, the Young's modulus of the human TM is measured using microindentation. A 10 mu m diameter spherical nanoindenter tip is used to indent the TM at different locations in the lateral and medial surfaces. Through a viscoelastic contact analysis, the steady state out-of-plane (through thickness) Young's modulus at a constant strain rate for the TM is determined from the uniaxial relaxation modulus. The measured spatial distribution of Young's modulus is reported for the entire TM pars tensa on both lateral and medial surfaces. The Young's modulus, for the four TM quadrants, is analyzed statistically using a normal quantile-quantile (Q-Q) plot. The obtained S-shaped curve indicates a bi-modal Gaussian distribution in the Q-Q plot. The spatial distribution of the Young's modulus is modeled by a bivariate Gaussian function in the polar coordinates over the entire TM on both the lateral and medial surfaces. It is shown that the anterior-superior quadrant has the smallest value of Young's modulus. Differences are observed in the spatial distribution of the Young's modulus for both the lateral and medial surfaces. For the medial surface, Young's modulus varies mainly along the radial direction following a small-large small trend, emanating from the umbo. For the lateral surface, the modulus at the anterior-superior quadrant shows the smallest modulus; the modulus decreases gradually along the radial directions. The quantitative results presented in this paper will help improve future simulation models of the middle ear by using spatial dependence of Young's modulus over the entire TM. (C) 2019 Elsevier B.V. All rights reserved.