Crack patterns of drying dense bacterial suspensions
Crack patterns of drying dense bacterial suspensions
复制标题
干燥致密细菌悬浮液的裂纹模式
DOI：
10.1039/d2sm00012a
复制
发表时间：
2022
期刊：
影响因子：
3.4
通讯作者：
Cheng, Xiang
中科院分区：
文献类型：
--
作者：
Ma, Xiaolei;Liu, Zhengyang;Zeng, Wei;Lin, Tianyi;Tian, Xin;Cheng, Xiang
细菌悬浮液的干燥在大量的自然和工程过程中经常遇到。然而，蒸发驱动的致密固结细菌悬浮液的机械不稳定性迄今尚未探索。在这里，我们报告了两种不同的裂纹模式的形成干燥悬浮液的大肠杆菌（E。coli）具有明显的运动行为。野生型E.大肠杆菌具有活跃的游动性，而不动细菌则形成螺旋状裂缝。利用弹性断裂力学和多孔弹性理论，我们表明，形成的圆形裂纹是由径向干燥应力的拉伸性质一旦裂纹是由细菌的局部有序结构，由于他们的集体游泳发起。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和宏观图案形成之间的联系。结果揭示了活性物质在干燥过程中的动力学，并为理解与干燥细菌悬浮液相关的各种生物过程提供了有用的信息。
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 Escherichia coli (E. coli) with distinct motile behaviors. Circular cracks are observed for wild-type 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.