To cross or not to cross: Collective swimming of Escherichia coli under two-dimensional confinement
To cross or not to cross: Collective swimming of Escherichia coli under two-dimensional confinement
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DOI：
10.1103/physrevresearch.4.023105
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发表时间：
2022-05-09
影响因子：
4.2
通讯作者：
Cheng, Xiang
中科院分区：
文献类型：
--
作者：
Ghosh, Dipanjan;Cheng, Xiang
悬浮在液体中的细菌集体游动，显示出迷人的涌现动力学。虽然细菌集体游泳在散装悬浮液中已经得到了很好的研究，但其在与许多细菌自然栖息地相关的受限二维（2D）几何中的对应物仍然知之甚少。在这里，通过在大肠杆菌上精心设计的Hele-Shaw几何形状的实验，我们表明，限制程度的微小变化导致细菌集体游泳的剧烈变化，而在相遇时可以相互交叉的细菌出现远距离向列顺序，阻止交叉的限制高度的轻微降低导致形成具有短程极性顺序的细菌簇。通过对单个细菌游动动力学的跟踪，揭示了这两个涌现的集体阶段的微观起源，并说明了集体动力学对单个细菌游动行为的影响。我们的研究为细菌在封闭条件下的集体游泳提供了见解，并展示了一种简单的方法来控制集体相的涌现对称性。
Bacteria suspended in fluids swim collectively and display fascinating emergent dynamics. Although bacterial collective swimming in bulk suspensions has been well studied, its counterpart in confined two-dimensional (2D) geometries relevant to many natural habitats of bacteria is still poorly understood. Here, through carefully designed experiments on Escherichia coli in a Hele-Shaw geometry, we show that a small change in the degree of confinement leads to a drastic change in bacterial collective swimming While a long-range nematic order emerges for bacteria that can cross over each other during encounters, a slight decrease of the confining height that prevents the crossing leads to the formation of bacterial clusters with a short-range polar order. By tracking the swimming kinetics of individual bacteria, we reveal the microscopic origins of the two emergent collective phases and illustrate the effect of the collective dynamics on the swimming behaviors of single bacteria. Our study provides insights into bacterial collective swimming under confinement and demonstrates a simple way to control the emergent symmetry of collective phases.