Micromechanical anisotropy and heterogeneity of the meniscus extracellular matrix.
Micromechanical anisotropy and heterogeneity of the meniscus extracellular matrix.
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DOI：
10.1016/j.actbio.2017.02.043
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发表时间：
2017-05
影响因子：
9.7
通讯作者：
Han L
中科院分区：
文献类型：
--
作者：
Li Q;Qu F;Han B;Wang C;Li H;Mauck RL;Han L
为了解半月板细胞外基质（ECM）的纳米结构如何赋予半月板复杂的生物力学功能，我们研究了半月板ECM微观力学性能的各向异性和异质性。我们利用原子力显微镜（AFM）在与胶原纤维直径相对应的变形长度尺度下，对幼年牛半月板随时间变化的力学性能进行量化。在此尺度下，主要的ECM结构单元——环形纤维弹性模量的各向异性可归因于纤维变形模式的差异：垂直于纤维轴时为伸直，平行于纤维轴时为横向受限压缩。不同结构单元之间的异质性主要与其微观纤维取向的变化有关，而不同解剖区域之间的异质性则是由于纳米尺度下胶原纤维直径和排列的改变。与弹性模量不同，随时间变化的特性在整个ECM中更具均质性和各向同性。这些结果能够详细了解纳米尺度下的半月板结构 - 力学，并且可以作为理解半月板生物力学功能、记录疾病进展以及设计组织修复策略的基准。
To understand how the complex biomechanical functions of the meniscus are endowed by the nanostructure of its extracellular matrix (ECM), we studied the anisotropy and heterogeneity in the micromechanical properties of the meniscus ECM. We used atomic force microscopy (AFM) to quantify the time-dependent mechanical properties of juvenile bovine meniscus at deformation length scales corresponding to the diameters of collagen fibrils. At this scale, anisotropy in the elastic modulus of the circumferential fibers, the major ECM structural unit, can be attributed to differences in fibril deformation modes: uncrimping when normal to the fiber axis, and laterally constrained compression when parallel to the fiber axis. Heterogeneity among different structural units is mainly associated with their variations in microscale fiber orientation, while heterogeneity across anatomical zones is due to alterations in collagen fibril diameter and alignment at the nanoscale. Unlike the elastic modulus, the time-dependent properties are more homogeneous and isotropic throughout the ECM. These results enable a detailed understanding of the meniscus structure-mechanics at the nanoscale, and can serve as a benchmark for understanding meniscus biomechanical function, documenting disease progression and designing tissue repair strategies.