Biological Soft Matter Group, Foundation for Fundamental Research on Matter, Institute for Atomic and Molecular Physics, Amsterdam, The Netherlands.
Biophys J. 2010 May 19;98(10):2281-9. doi: 10.1016/j.bpj.2010.01.040.
Fibrin gels are responsible for the mechanical strength of blood clots, which are among the most resilient protein materials in nature. Here we investigate the physical origin of this mechanical behavior by performing rheology measurements on reconstituted fibrin gels. We find that increasing levels of shear strain induce a succession of distinct elastic responses that reflect stretching processes on different length scales. We present a theoretical model that explains these observations in terms of the unique hierarchical architecture of the fibers. The fibers are bundles of semiflexible protofibrils that are loosely connected by flexible linker chains. This architecture makes the fibers 100-fold more flexible to bending than anticipated based on their large diameter. Moreover, in contrast with other biopolymers, fibrin fibers intrinsically stiffen when stretched. The resulting hierarchy of elastic regimes explains the incredible resilience of fibrin clots against large deformations.
纤维蛋白凝胶负责血栓的机械强度，它是自然界中最有弹性的蛋白质材料之一。在这里，我们通过对重组纤维蛋白凝胶进行流变学测量来研究这种机械行为的物理起源。我们发现，增加剪切应变水平会引起一系列不同的弹性响应，这些响应反映了不同长度尺度上的拉伸过程。我们提出了一个理论模型，根据纤维的独特层次结构解释了这些观察结果。纤维是由半弹性原纤维组成的束，通过柔性连接链松散地连接。这种结构使纤维在弯曲时的柔韧性比根据其大直径预期的柔韧性高出 100 倍。此外，与其他生物聚合物不同，纤维蛋白纤维在拉伸时会固有地变硬。由此产生的弹性状态层次结构解释了纤维蛋白凝块对大变形的难以置信的弹性。
