论文标题
干燥密集细菌悬浮液的裂纹模式
Crack patterns of drying dense bacterial suspensions
论文作者
论文摘要
细菌悬浮液的干燥经常在许多天然和工程过程中遇到。然而，尚未探索以蒸发驱动的密集巩固细菌悬浮液的机械不稳定性。在这里，我们报告了\ textit {escherichia coli}（\ textit {e。coli}）的两种不同的干燥悬浮液的裂纹模式的形成。对于野生型\ textit {e。大肠杆菌具有活跃的游泳，而螺旋状的裂纹形成了疫苗的细菌。使用弹性断裂力学和毛弹性理论，我们表明圆形裂纹的形成是由径向干燥应力的拉伸性质确定的，一旦裂纹是由细菌的局部阶阶构成由于其集体游泳而引发的。我们的研究证明了单个细菌的微观游泳行为与干燥细菌膜的机械不稳定性与宏观模式形成之间的联系。结果阐明了在干燥过程中活跃物质的动力学，并提供了有用的信息，以了解与干燥细菌悬浮液相关的各种生物学过程。
Drying of bacterial suspensions is frequently encountered in a plethora of natural and engineering processes. However, the evaporation-driven mechanical instabilities of dense consolidating bacterial suspensions have not been explored heretofore. Here, we report the formation of two different crack patterns of drying suspensions of \textit{Escherichia coli} (\textit{E. coli}) with distinct motile behaviors. Circular cracks are observed for wild-type \textit{E. coli} with active swimming, whereas spiral-like cracks form for immotile bacteria. Using the elastic fracture mechanics and the poroelastic theory, we show that the formation of the circular cracks is determined by the tensile nature of the radial drying stress once the cracks are initiated by the local order structure of bacteria due to their collective swimming. Our study demonstrates the link between the microscopic swimming behaviors of individual bacteria and the mechanical instabilities and macroscopic pattern formation of drying bacterial films. The results shed light on the dynamics of active matter in a drying process and provide useful information for understanding various biological processes associated with drying bacterial suspensions.
