Chemically encapsulated structural elements for probing the mechanical responses of biologically inspired systems
Chemically encapsulated structural elements for probing the mechanical responses of biologically inspired systems
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DOI：
10.1021/la700488p
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发表时间：
2007-07-17
期刊：
影响因子：
3.9
通讯作者：
LeDuc, Philip R.
中科院分区：
文献类型：
--
作者：
Zhang, Ying;Cheng, Chao-min;LeDuc, Philip R.
活细胞有一个拥挤的环境，分子密集分布，需要结构化的组织才能有效发挥作用。这种结构的一个组成部分，肌动蛋白细胞骨架，是必不可少的提供机械支持和促进许多反应活动，包括肌肉细胞的收缩和趋化性。尽管许多研究已经从体内或体外的角度提供了对机械响应的深入了解，但在确定活细胞响应和聚合物物理响应如何桥接方面存在显著的差距。对这些系统的理解包括研究它们的组成部分，包括活细胞中个体细胞骨架元素与高级生物组织。在这里，我们利用这种组织的性质，通过使用化学为基础的方法来模仿细胞骨架在人工环境组成的球形分布的脂质双层。这种结构与细胞膜有相似之处。为了创造一个结构调节的环境，我们封装G-肌动蛋白成巨大的单层囊泡，然后在单个脂质体内的肌动蛋白丝。我们用落射荧光显微镜和共聚焦显微镜观察这些囊泡。然后使用原子力显微镜来探测这些人造细胞的机械特性。这种聚合物细胞骨架网络似乎与脂质双层连接，并以类似于在活细胞中观察到的方式跨越脂质体内的内部空间。这项工作将在各种领域，包括化学，高分子物理，结构生物学和工程力学的影响。
A living cell has a crowded environment with a dense distribution of molecules that requires structured organization for its efficient functioning. One component of this structure, the actin cytoskeleton, is essential for providing mechanical support and facilitating many response activities, including the contraction of muscle cells and chemotaxis. Whereas many investigations have provided insight into the mechanical response from either an in vivo or in vitro perspective, a significant gap exists in determining how the living cell response and the polymer physics response are bridged. The understanding of these systems involves studying their components, including the individual cytoskeletal elements versus the higher-order organism organization in a living cell. Here, we leverage this organization in nature by using a chemistry-based approach to mimic the cytoskeleton in an artificial environment composed of spherically distributed lipid bilayers. This construct bears similarities to the cell membrane. To create a structurally regulated environment, we encapsulate G-actin into giant unilamellar vesicles and then polymerize actin filaments within individual liposomes. We visualize these vesicles with epifluorescence microscopy and confocal microscopy. Atomic force microscopy is then used to probe the mechanical properties of these artificial cells. This polymer cytoskeletal network appears to connect with the lipid bilayer and span the internal space within the liposomes in a manner similar to what is observed in living cells. This work will have implications in a variety of fields, including chemistry, polymer physics, structural biology, and engineering mechanics.