Uncovering the dynamic precursors to motor-driven contraction of active gels

摘要: Cells and tissues have the remarkable ability to actively generate forces required change their shape. This active mechanical behavior is largely mediated by actin cytoskeleton, a crosslinked network of filaments that contracted myosin motors. Experiments gel theories established length scale over which contraction occurs governed balance between molecular motor activity crosslink density. By contrast, dynamics govern contractile cytoskeleton remain poorly understood. Here we investigate microscopic reconstituted actin–myosin networks using simultaneous real-space video microscopy Fourier-space dynamic light scattering. Light scattering reveals different regimes as function sample age. We uncover two dynamical precursors precede macroscopic contraction. One characterized progressive acceleration stress-induced rearrangements, while other consists sudden, heterogeneous rearrangements. Intriguingly, our findings suggest qualitative analogy self-driven rupture collapse gels delayed passive observed in earlier studies colloidal under external loads.