Motility-induced buckling and glassy dynamics regulate 3D transitions in bacterial colonies

A key step in the development of many bacterial colonies and biofilms is a transition from a two-dimensional (2D) monolayer into a three-dimensional (3D) structure. In this talk, we explore the mechanisms behind the 2D-to-3D transition of motile Pseudomonas aeruginosa colonies. We show that the viscous shear stresses and dynamic pressures arising from bacterial swarming allow cells to overcome cell-substrate adhesion, leading to rate-dependent buckling into the third dimension. Furthermore, we show that bacterial monolayers exhibit a crossover from a swarming state to a kinetically-arrested, glassy-like state above an onset density, resulting in a distinct 2D-to-3D transition. In our approach, we combine experimental observations of P. aeruginosa colonies at single-cell resolution, molecular dynamics simulations of active particles, and theories of 2D fluid films. We develop a dynamical state diagram to predict the various buckling mechanisms governing the 2D-to-3D transitions in bacterial colonies.

See our corresponding work at:
S. C. Takatori, and K. K. Mandadapu, “Motility-induced buckling and glassy dynamics regulate three-dimensional transitions of bacterial monolayers”, arXiv:2003.05618 (2020).