Measurement of the mechanical properties of isolated tectorial membrane using atomic force microscopy
Measurement of the mechanical properties of isolated tectorial membrane using atomic force microscopy
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DOI：
10.1073/pnas.0603429103
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发表时间：
2006-10-03
影响因子：
11.1
通讯作者：
Rousso, Itay
中科院分区：
文献类型：
--
作者：
Gueta, Rachel;Barlam, David;Rousso, Itay
盖膜（TM）是位于耳蜗感觉细胞上的细胞外基质。它的战略位置，以及最近TM特异性突变研究的结果表明，它在耳蜗将机械能转换为神经兴奋的机制中起着重要作用。TM机械性能的详细表征是理解其在耳蜗力学中的作用的基础。在这项工作中，TM的机械性能，其特征在于在径向和纵向方向上使用纳米和微米压痕实验，通过使用原子力光谱。我们发现，在主体区域和螺旋利姆布斯附着区的刚度不改变显着沿着长度的耳蜗。TM的主体是最软的区域，而螺旋利姆布斯附着区较硬，两个区域的平均杨氏模量值分别为37 +/- 3和135 +/- 14 kPa。相比之下，我们发现，TM的刚度的区域以上的外毛细胞（OHC）的纵向方向上增加了一个数量级，从24 - 4千帕的顶端区域的210 +/- 15千帕在基底端的TM。扫描电子显微镜分析显示，TM的OHC区中的胶原纤维排列存在差异，这与观察到的机械性能变化相对应。TM刚度的纵向增加与OHC静纤毛的纵向增加相似，这支持了这两种结构之间存在机械耦合。
The tectorial membrane (TM) is an extracellular matrix situated over the sensory cells of the cochlea. Its strategic location, together with the results of recent TM-specific mutation studies, suggests that it has an important role in the mechanism by which the cochlea transduces mechanical energy into neural excitation. A detailed characterization of TM mechanical properties is fundamental to understanding its role in cochlear mechanics. In this work, the mechanical properties of the TM are characterized in the radial and longitudinal directions using nano- and microindentation experiments conducted by using atomic force spectroscopy. We find that the stiffness in the main body region and in the spiral limbus attachment zone does not change significantly along the length of the cochlea. The main body of the TM is the softest region, whereas the spiral limbus attachment zone is stiffer, with the two areas having averaged Young's modulus values of 37 +/- 3 and 135 +/- 14 kPa, respectively. By contrast, we find that the stiffness of the TM in the region above the outer hair cells (OHCs) increases by one order of magnitude in the longitudinal direction, from 24 4 kPa in the apical region to 210 +/- 15 kPa at the basilar end of the TM. Scanning electron microscopy analysis shows differences in the collagen fiber arrangements in the OHC zone of the TM that correspond to the observed variations in mechanical properties. The longitudinal increase in TM stiffness is similar to that found for the OHC stereocilia, which supports the existence of mechanical coupling between these two structures.