论文标题
交联的移动性控制着接管网络的断裂行为
Crosslinker mobility governs fracture behavior of catch-bonded networks
论文作者
论文摘要
尽管大多数化学键在机械力的作用下（称为滑动键行为）削弱，但自然发展了键相反的键：它们的寿命随着力的应用而增加。尽管在单分子水平和粘合触点上对这种捕获键进行了广泛的研究，但最近的工作表明它们在肌动蛋白细胞骨架中也充满了交联。但是，它们在这些网络中运行的作用和机制尚不清楚。在这里，我们提出了计算机模拟，以显示如何与滑移或捕获键交联的聚合物网络应对机械应力。我们的结果表明，可能需要捕获粘结以保护动态网络免受断裂的影响，特别是对于可以在解开后可以自由扩散的移动接头。尽管移动滑移键导致网络在高应力下非常弱，但移动捕获键在高应力区域积累，从而稳定裂缝，从而导致更具延展性的断裂行为。这使细胞可以在低应力下结合结构适应性，并在高应力下的机械稳定性结合。
While most chemical bonds weaken under the action of mechanical force (called slip bond behavior), nature has developed bonds that do the opposite: their lifetime increases as force is applied. While such catch bonds have been studied quite extensively at the single molecule level and in adhesive contacts, recent work has shown that they are also abundantly present as crosslinkers in the actin cytoskeleton. However, their role and the mechanism by which they operate in these networks have remained unclear. Here, we present computer simulations that show how polymer networks crosslinked with either slip or catch bonds respond to mechanical stress. Our results reveal that catch bonding may be required to protect dynamic networks against fracture, in particular for mobile linkers that can diffuse freely after unbinding. While mobile slip bonds lead to networks that are very weak at high stresses, mobile catch bonds accumulate in high stress regions and thereby stabilize cracks, leading to a more ductile fracture behavior. This allows cells to combine structural adaptivity at low stresses with mechanical stability at high stresses.
