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活性颗粒可在大型脂质囊泡中引起较大的形状改变
作者:小柯机器人 发布时间:2020/10/4 22:48:34

德国Forschungszentrum Jülich研究所Jan Vermant小组发现,活性颗粒可在大型脂质囊泡中引起较大的形状改变。相关论文发表在2020年9月30日出版的《自然》杂志上。

研究人员提出了一个组合的实验和模拟研究,表明封闭在巨大的单层囊泡中的自推进颗粒如何引起过多的非平衡形状和主动膜波动。使用共聚焦显微镜,研究人员在实验中探索了膜对自电泳Janus微游泳器施加的局部力响应。为了量化动态膜的变化,研究人员对封装在由动态三角化表面建模的薄膜壳活性布朗粒子进行Langevin动力学模拟。
 
在低和中等的颗粒负载下观察到最明显形状变化,从而形成系绳状突起和高度分支的树突结构,而在高体积分数下观察到整体变形的囊泡形状。最终的状态图预测了局部内力产生各种膜形状的条件。这种变形囊泡形态的受控实现可以改善诸如小型软体机器人和合成细胞等人工系统的设计。
 
据介绍,生物细胞通过从内部改变细胞膜来主动感知并响应外部刺激或探索其环境,从而产生复杂的结构。几种致病细菌还提供了局部力如何从内部强烈变形细胞膜,从而导致邻近健康哺乳动物细胞入侵的例子。巨大的单层囊泡已成功用作模拟生物细胞的最小模型系统,并实现了具有局部主动内力的最小系统,可以使内部和外部的脂膜强烈变形。但导致形状急剧变化仍然具有挑战性。
 
附:英文原文

Title: Active particles induce large shape deformations in giant lipid vesicles

Author: Hanumantha Rao Vutukuri, Masoud Hoore, Clara Abaurrea-Velasco, Lennard van Buren, Alessandro Dutto, Thorsten Auth, Dmitry A. Fedosov, Gerhard Gompper, Jan Vermant

Issue&Volume: 2020-09-30

Abstract: Biological cells generate intricate structures by sculpting their membrane from within to actively sense and respond to external stimuli or to explore their environment1,2,3,4. Several pathogenic bacteria also provide examples of how localized forces strongly deform cell membranes from inside, leading to the invasion of neighbouring healthy mammalian cells5. Giant unilamellar vesicles have been successfully used as a minimal model system with which to mimic biological cells6,7,8,9,10,11, but the realization of a minimal system with localized active internal forces that can strongly deform lipid membranes from within and lead to dramatic shape changes remains challenging. Here we present a combined experimental and simulation study that demonstrates how self-propelled particles enclosed in giant unilamellar vesicles can induce a plethora of non-equilibrium shapes and active membrane fluctuations. Using confocal microscopy, in the experiments we explore the membrane response to local forces exerted by self-phoretic Janus microswimmers. To quantify dynamic membrane changes, we perform Langevin dynamics simulations of active Brownian particles enclosed in thin membrane shells modelled by dynamically triangulated surfaces. The most pronounced shape changes are observed at low and moderate particle loadings, with the formation of tether-like protrusions and highly branched, dendritic structures, whereas at high volume fractions globally deformed vesicle shapes are observed. The resulting state diagram predicts the conditions under which local internal forces generate various membrane shapes. A controlled realization of such distorted vesicle morphologies could improve the design of artificial systems such as small-scale soft robots and synthetic cells.

DOI: 10.1038/s41586-020-2730-x

Source: https://www.nature.com/articles/s41586-020-2730-x

期刊信息

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:43.07
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html