Continuum modeling of bacterial biofilm development*

Biofilms are surface-associated bacterial communities embedded in an extracellular matrix. Vibrio cholerae, a rod-shaped bacterium, forms biofilms starting from a single cell and growing into a three-dimensional structure. Recent advances in single-cell imaging reveal the kinematics of this developmental process with single-cell resolution. To understand the role of mechanics in shaping the biofilm, we develop a multiphase continuum model of biofilm development. We find that the kinetic friction between the growing biofilm and the surface leads to a universal “fountain-like” flow of material within the biofilm, in good agreement with experimental data. Using a phase-field approach, we study how cell-cell and cell-matrix mechanical interactions affect the internal organization of cells in the growing biofilm.