Department of Complex Fluids, Max Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany.
Institute for the Dynamics of Complex Systems, Georg August Universität, 37077 Göttingen, Germany.
Proc Natl Acad Sci U S A. 2022 Jun 14;119(24):e2122269119. doi: 10.1073/pnas.2122269119. Epub 2022 Jun 9.
A common feature of biological self-organization is how active agents communicate with each other or their environment via chemical signaling. Such communications, mediated by self-generated chemical gradients, have consequences for both individual motility strategies and collective migration patterns. Here, in a purely physicochemical system, we use self-propelling droplets as a model for chemically active particles that modify their environment by leaving chemical footprints, which act as chemorepulsive signals to other droplets. We analyze this communication mechanism quantitatively both on the scale of individual agent-trail collisions as well as on the collective scale where droplets actively remodel their environment while adapting their dynamics to that evolving chemical landscape. We show in experiment and simulation how these interactions cause a transient dynamical arrest in active emulsions where swimmers are caged between each other's trails of secreted chemicals. Our findings provide insight into the collective dynamics of chemically active particles and yield principles for predicting how negative autochemotaxis shapes their navigation strategy.
生物自组织的一个共同特征是活性物质如何通过化学信号与彼此或环境进行通信。这种由自我产生的化学梯度介导的通信，对个体运动策略和集体迁移模式都有影响。在这里，在一个纯粹的物理化学系统中，我们使用自推进液滴作为化学活性粒子的模型，这些粒子通过留下化学足迹来改变环境，这些足迹作为化感排斥信号作用于其他液滴。我们在个体剂轨碰撞的尺度以及集体尺度上对这种通信机制进行了定量分析，在集体尺度上，液滴主动重塑环境，同时使它们的动力学适应不断变化的化学景观。我们通过实验和模拟展示了这些相互作用如何导致活性乳液中的瞬时动力学停滞，其中游泳者被彼此分泌的化学物质轨迹之间的笼子困住。我们的发现为化学活性粒子的集体动力学提供了深入的了解，并为预测负自趋化性如何塑造它们的导航策略提供了原理。
