Institute of Theoretical and Applied Research, Duy Tan University, Ha Noi 100 000, Viet Nam.
Faculty of Natural Science, Duy Tan University, Da Nang 550 000, Viet Nam.
J R Soc Interface. 2021 Apr;18(177):20210100. doi: 10.1098/rsif.2021.0100. Epub 2021 Apr 14.
Complex interactions between cellular systems and their surrounding extracellular matrices are emerging as important mechanical regulators of cell functions, such as proliferation, motility and cell death, and such cellular systems are often characterized by pulsating actomyosin activities. Here, using an active gel model, we numerically explore spontaneous flow generation by activity pulses in the presence of a viscoelastic medium. The results show that cross-talk between the activity-induced deformations of the viscoelastic surroundings and the time-dependent response of the active medium to these deformations can lead to the reversal of spontaneously generated active flows. We explain the mechanism behind this phenomenon based on the interaction between the active flow and the viscoelastic medium. We show the importance of relaxation time scales of both the polymers and the active particles and provide a phase space over which such spontaneous flow reversals can be observed. Our results suggest new experiments investigating the role of controlled pulses of activity in living systems ensnared in complex mircoenvironments.
细胞系统及其周围细胞外基质之间的复杂相互作用正成为细胞功能（如增殖、运动和细胞死亡）的重要机械调节因子，而这些细胞系统的特征通常是肌动球蛋白活性的脉动。在这里，我们使用活性凝胶模型，数值研究了在粘弹性介质存在下，活性脉冲自发产生流动的情况。结果表明，活性周围环境变形引起的串扰和活性介质对这些变形的时变响应之间的相互作用，可能导致自发产生的活性流的反转。我们基于活性流和粘弹性介质之间的相互作用，解释了这一现象背后的机制。我们展示了聚合物和活性粒子的松弛时间尺度的重要性，并提供了一个可以观察到这种自发流反转的相空间。我们的结果表明，在复杂微环境中捕捉到的活系统中，进行受控活性脉冲的新实验具有重要意义。
