拥挤分子凝聚对丝状网络刚性的控制
Control of filament network rigidity by the condensation of crowding molecules
- School of Physics, Georgia Institute of Technology（佐治亚理工学院物理学院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过实验证明大分子拥挤剂的液-液相分离通过调节渗透压调控丝状网络刚性，实现可逆的力学转变，为动态可调丝状材料设计提供范式。
AI中文摘要：
理解液-液相分离如何影响丝状网络的力学特性，是处于生物细胞过程和软材料设计核心的基本物理问题。尽管已有一些理论机制被提出，但缺乏对相分离与整体网络刚度直接耦合的清晰实验证明。我们报道了揭示一种普适机制的实验，即大分子拥挤剂的凝聚诱导模型丝状网络发生刚性转变。我们重构了刚性、空间相互作用的螺旋丝状物和聚合物拥挤剂。最初，大分子均匀溶解，丝状物形成束状结构，组装成刚性的缠结网络。一旦拥挤剂凝聚成液滴，网络结构丧失刚性，其力学响应减弱了一个数量级。随后凝聚体的溶解伴随着刚性的重新建立。我们的结果表明，拥挤剂的相分离通过调节维持网络结合的渗透压来调控丝状网络的力学特性。这一原理可能作为设计动态可调丝状材料的范式。
英文摘要：
Understanding how liquid-liquid phase separation impacts the mechanics of filament networks is a fundamental physical problem at the heart of biological cellular processes and soft material design. While a few theoretical mechanisms have been proposed, a clear demonstration of the direct coupling of phase separation to the overall network stiffness is missing. We report experiments that reveal a universal mechanism by which the condensation of macromolecular crowders induces a rigidity transition in a model filament network. We reconstituted stiff sterically interacting helical filaments and polymeric crowders. Initially, the macromolecules were uniformly dissolved and the filaments formed bundles that assembled a rigid entangled network. Once the crowders condensed into droplets, the network structure lost its rigidity and its mechanical response weakened by an order-of-magnitude. The subsequent dissolution of the condensates was accompanied by the re-establishment of rigidity. Our results show that crowder phase separation modulates the mechanics of filament networks by tuning the osmotic pressure holding the network together. This principle may serve as a paradigm for devising dynamically tunable filamentous materials.
