在发生剪切带的溶液中直接观察肌动蛋白丝的取向分布。

Direct observation of orientation distributions of actin filaments in a solution undergoing shear banding.

机构信息

Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020, Japan.

Department of Information Engineering, Faculty of Engineering, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan.

出版信息

Soft Matter. 2017 Apr 5;13(14):2708-2716. doi: 10.1039/c6sm02832b.

DOI:10.1039/c6sm02832b

PMID:28337500

Abstract

Shear banding is frequently observed in complex fluids. However, the configuration of macromolecules in solutions undergoing shear banding has not yet been directly observed. In this study, by using the fact that F-actin solutions exhibit shear banding and actin filaments are visualized by fluorescent labels, we directly observed the intrinsic states of an actin solution undergoing shear banding. By combining the 3D imaging of labeled actin filaments and particle image velocimetry (PIV), we obtained orientation distributions of actin filaments in both high and low shear rate regions, whose quantitative differences are indicated. In addition, by using the orientation distributions and applying stress expression for rod-like polymers, we estimated stress tensors in both high and low shear rate regions. This evaluation indicates that different orientation distributions of filamentous macromolecules can exhibit a common shear stress.

摘要

切变带在复杂流体中经常被观察到。然而，在发生切变带的溶液中，大分子的构象尚未被直接观察到。在本研究中，利用 F-肌动蛋白溶液表现出切变带，并且肌动蛋白丝可以被荧光标记物可视化的事实，我们直接观察了处于切变带的肌动蛋白溶液的固有状态。通过结合标记的肌动蛋白丝的 3D 成像和粒子图像测速法（PIV），我们获得了在高和低剪切速率区域中肌动蛋白丝的取向分布，其定量差异得到了指示。此外，通过使用取向分布并应用棒状聚合物的应力表达式，我们在高和低剪切速率区域中估计了应力张量。这种评估表明，丝状大分子的不同取向分布可以表现出共同的剪切应力。