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arXiv 2103.02106cond-mat.softphysics.bio-ph
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一种用于脂质和聚合物膜高通量粘度测量的囊泡微流变仪

A vesicle microrheometer for high-throughput viscosity measurements of lipid and polymer membranes

Hammad A. Faizi, Rumiana Dimova, Petia M. Vlahovska

AI总结:

本研究提出一种基于巨型单层囊泡瞬态变形的膜粘度测量新方法,可无创高通量检测多种脂质和聚合物膜粘度,发现不同膜体系的流变特性差异及膜极化对粘度的调控作用。

摘要:

粘度是细胞膜的关键属性,控制着嵌入蛋白的流动性和膜的重塑过程。测量膜粘度颇具挑战,因为现有方法涉及复杂的实验设计和/或模型,且部分方法的适用性仅限于特定系统和膜组成。由此导致相关数据匮乏,同一系统的膜粘度报道值差异可达数个数量级。本文中,我们展示了如何通过巨型单层囊泡的瞬态变形获取双层膜的粘度。该方法可对多种组成和相态的脂质或聚合物双层膜进行无创、不依赖探针的高通量粘度测量。研究发现,纯脂质和单相混合双层膜表现为牛顿流体,其粘度与应变速率无关;而在1-2000 $s^{-1}$的研究应变速率范围内,相分离系统和二嵌段共聚物系统表现出剪切稀化特性。研究结果还表明,电极化双层膜的粘度远高于电中性双层膜。这些发现说明,生物膜粘度是一种动态属性,不仅可通过膜组成主动调节,还可通过膜极化(如动作电位中的极化过程)主动调控。

英文摘要:

Viscosity is a key property of cell membranes that controls mobility of embedded proteins and membrane remodeling. Measuring it is challenging because existing approaches involve complex experimental designs and/or models, and the applicability of some is limited to specific systems and membrane compositions. As a result there is scarcity of data and the reported values for membrane viscosity vary by orders of magnitude for the same system. Here, we show how viscosity of bilayer membranes can be obtained from the transient deformation of giant unilamellar vesicles. The approach enables a non-invasive, probe-independent and high-throughput measurement of the viscosity of bilayers made of lipids or polymers with a wide range of compositions and phase state. Pure lipid and single-phase mixed bilayers are found to behave as Newtonian fluids with strain-rate independent viscosity, while phase-separated and diblock-copolymers systems exhibit shear-thinning in the explored range of strain rates 1-2000 $s^{-1}$. The results also reveal that electrically polarized bilayers can be significantly more viscous than charge-neutral bilayers. These findings suggest that biomembrane viscosity is a dynamic property that can be actively modulated not only by composition but also by membrane polarization, e.g., as in action potentials.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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