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研究揭示纤维网络与细胞的组织力学关系
2019-08-29 16:23

美国宾夕法尼亚大学Paul A. Janmey以及Vivek B. Shenoy研究组合作揭示了纤维网络与细胞的组织力学关系。相关论文2019年8月28日在线发表于《自然》。

研究人员使用多个实验系统和理论模型表明,非线性聚合物网络弹性和粒子(细胞)包含物的组合对于模拟组织力学是必不可少的,这些组织力学不能仅由生物聚合物网络或胶体粒子系统重现。组织流变学来自应变硬化聚合物网络和其中的体积保存细胞之间的相互作用。通过在网络内包括细胞或惰性颗粒以限制围绕它们纤维网络的松弛模式,可以将压缩软化但延伸变硬的聚合物网络转化为在压缩中变硬但不延伸的材料。颗粒夹杂物也抑制剪切变形的硬化;当颗粒体积分数低时,它们对聚合物网络的弹性几乎没有影响。然而,随着颗粒变得更紧密地堆积,材料从压缩软化转变为压缩硬化。这些复合材料中弹性反应的出现对组织硬度如何在疾病中发生改变并导致细胞功能障碍有影响。此外,该发现可用于具有生理学相关机械性质生物材料的设计。

据介绍,交联半柔性聚合物网络(例如内部细胞骨架和细胞外基质)的粘弹性被认为主导了组织力学,其提供形状和机械的抗变形能力。然而,软组织和半柔性聚合物凝胶的机械响应在许多方面都不同。组织在压缩时变硬但在拉伸时却没有,而半柔性聚合物网络在压缩时变软并在拉伸中变硬。在剪切变形中,半柔性聚合物凝胶随着应变增加而变硬,但组织则不然。

附:英文原文

Title: Emergence of tissue-like mechanics from fibrous networks confined by close-packed cells

Author: Anne S. G. van Oosten, Xingyu Chen, LiKang Chin, Katrina Cruz, Alison E. Patteson, Katarzyna Pogoda, Vivek B. Shenoy, Paul A. Janmey

Issue&Volume: 2019-08-28

Abstract: The viscoelasticity of the crosslinked semiflexible polymer networks—such as the internal cytoskeleton and the extracellular matrix—that provide shape and mechanical resistance against deformation is assumed to dominate tissue mechanics. However, the mechanical responses of soft tissues and semiflexible polymer gels differ in many respects. Tissues stiffen in compression but not in extension1,2,3,4,5, whereas semiflexible polymer networks soften in compression and stiffen in extension6,7. In shear deformation, semiflexible polymer gels stiffen with increasing strain, but tissues do not1,2,3,4,5,6,7,8. Here we use multiple experimental systems and a theoretical model to show that a combination of nonlinear polymer network elasticity and particle (cell) inclusions is essential to mimic tissue mechanics that cannot be reproduced by either biopolymer networks or colloidal particle systems alone. Tissue rheology emerges from an interplay between strain-stiffening polymer networks and volume-conserving cells within them. Polymer networks that soften in compression but stiffen in extension can be converted to materials that stiffen in compression but not in extension by including within the network either cells or inert particles to restrict the relaxation modes of the fibrous networks that surround them. Particle inclusions also suppress stiffening in shear deformation; when the particle volume fraction is low, they have little effect on the elasticity of the polymer networks. However, as the particles become more closely packed, the material switches from compression softening to compression stiffening. The emergence of an elastic response in these composite materials has implications for how tissue stiffness is altered in disease and can lead to cellular dysfunction9,10,11. Additionally, the findings could be used in the design of biomaterials with physiologically relevant mechanical properties.

DOI: 10.1038/s41586-019-1516-5

Source: https://www.nature.com/articles/s41586-019-1516-5

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:69.504
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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