Fibrin Networks Support Recurring Mechanical Loads by Adapting their Structure across Multiple Scales
Fibrin Networks Support Recurring Mechanical Loads by Adapting their Structure across Multiple Scales
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DOI：
10.1016/j.bpj.2016.06.034
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发表时间：
2016-09-06
影响因子：
3.4
通讯作者：
Koenderink, Gijsje H.
中科院分区：
文献类型：
--
作者：
Kurniawan, Nicholas A.;Vos, Bart E.;Koenderink, Gijsje H.
由于暴露于血流、肌肉活动和外部冲击，组织和细胞承受着广泛的负载幅度和时间尺度的重复机械负载。组织和细胞的机械强度都来自纤维蛋白支架，该支架通常具有复杂的层次结构。在这项研究中，我们重点关注一种典型的分层生物材料——纤维蛋白，它是最具弹性的天然生物聚合物之一，形成血栓的结构支架。我们展示了由纤维蛋白组成的纤维网络如何在不同尺度上利用其分层结构的不可逆变化来维持大应变的可逆应力硬化。为了追踪这种矛盾弹性的起源，据我们所知，我们系统地调整了纤维蛋白的微观结构参数，并使用光学镊子和荧光显微镜相结合，首次测量了单个纤维蛋白纤维的相互作用。我们证明，纤维蛋白网络通过纤维之间自发形成新的键在网络尺度上进行重塑来适应中等应变，而它们通过纤维本身的塑性重塑来适应高应变。这种多尺度适应机制赋予纤维蛋白凝胶卓越的能力，以承受剪切流和伤口拉伸引起的反复负载。因此，我们的研究结果揭示了组织和细胞平衡弹性非线性和可塑性的微观机制，从而可以为细胞驱动的组织重塑提供微观结构的见解。
Tissues and cells sustain recurring mechanical loads that span a wide range of loading amplitudes and timescales as a consequence of exposure to blood flow, muscle activity, and external impact. Both tissues and cells derive their mechanical strength from fibrous protein scaffolds, which typically have a complex hierarchical structure. In this study, we focus on a prototypical hierarchical biomaterial, fibrin, which is one of the most resilient naturally occurring biopolymers and forms the structural scaffold of blood clots. We show how fibrous networks composed of fibrin utilize irreversible changes in their hierarchical structure at different scales to maintain reversible stress stiffening up to large strains. To trace the origin of this paradoxical resilience, we systematically tuned the microstructural parameters of fibrin and used a combination of optical tweezers and fluorescence microscopy to measure the interactions of single fibrin fibers for the first time, to our knowledge. We demonstrate that fibrin networks adapt to moderate strains by remodeling at the network scale through the spontaneous formation of new bonds between fibers, whereas they adapt to high strains by plastic remodeling of the fibers themselves. This multiscale adaptation mechanism endows fibrin gels with the remarkable ability to sustain recurring loads due to shear flows and wound stretching. Our findings therefore reveal a microscopic mechanism by which tissues and cells can balance elastic nonlinearity and plasticity, and thus can provide microstructural insights into cell-driven remodeling of tissues.