Direct visualization of flow-induced conformational transitions of single actin filaments in entangled solutions
Direct visualization of flow-induced conformational transitions of single actin filaments in entangled solutions
复制标题
直接可视化缠结溶液中单肌动蛋白丝的流动诱导构象转变
DOI：
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发表时间：
2014
影响因子：
16.6
通讯作者：
M. Paul Lettinga
中科院分区：
文献类型：
--
作者：
Inka Kirchenbuechler;D. Guu;Nicholas A. Kurniawan;G. Koenderink;M. Paul Lettinga
虽然半柔性聚合物和纤维因其丰富的机械性能而成为一类重要的材料，但目前尚不清楚这些性能与聚合物的微观构象有何关系。肌动蛋白丝构成了理想的模型聚合物系统，因为它们具有微米级的长度和相对较高的刚度，允许在单丝水平上成像。在这里，我们研究了剪切流中缠结对肌动蛋白丝构象动力学的影响。我们使用共焦显微镜结合反向旋转锥板剪切池直接测量单肌动蛋白丝的完整三维构象。我们表明，最初缠结的细丝形成解开的定向有序发夹，限制在流涡平面内。此外，剪切流导致发夹尾部拉伸和剪切对齐，而长丝长度分布保持不变。这些观察结果解释了缠结的 F-肌动蛋白溶液的应变软化和剪切稀化行为，这有助于理解含有半柔性聚合物的复杂流体的流动行为。半柔性聚合物是活细胞中重要的结构构件，具有独特的机械性能。在这里，作者将剪切诱导的肌动蛋白丝构象转变可视化为研究细胞质流中细胞形成的模型系统。
While semi-flexible polymers and fibres are an important class of material due to their rich mechanical properties, it remains unclear how these properties relate to the microscopic conformation of the polymers. Actin filaments constitute an ideal model polymer system due to their micron-sized length and relatively high stiffness that allow imaging at the single filament level. Here we study the effect of entanglements on the conformational dynamics of actin filaments in shear flow. We directly measure the full three-dimensional conformation of single actin filaments, using confocal microscopy in combination with a counter-rotating cone-plate shear cell. We show that initially entangled filaments form disentangled orientationally ordered hairpins, confined in the flow-vorticity plane. In addition, shear flow causes stretching and shear alignment of the hairpin tails, while the filament length distribution remains unchanged. These observations explain the strain-softening and shear-thinning behaviour of entangled F-actin solutions, which aids the understanding of the flow behaviour of complex fluids containing semi-flexible polymers. Semi-flexible polymers are an important structural building block in living cells, which possess unique mechanical properties. Here, the authors visualize the shear-induced conformational transition of actin filaments as a model system to study cell formation in cytoplasmic flows.
影响因子：
3.4
作者：
Kas, J;Strey, H;Janmey, PA
通讯作者：
Janmey, PA
半稀释状态下半柔性聚合物溶液非牛顿粘度的微观起源
影响因子：
7.015
作者：
B. Huber;M.B. Harasim;B. Wunderlich;M. Kröger;A.R. Bausch
通讯作者：
A.R. Bausch
影响因子：
8.6
作者：
Harasim, Markus;Wunderlich, Bernhard;Bausch, Andreas R.
通讯作者：
Bausch, Andreas R.