A simulation model of biofilms with autonomous cells: I. Analysis of a two-dimensional version

We introduce a single-cell based simulation model of biofilm growth. Each microbial cell is modelled as an autonomous agent whose behavior is controlled by thermodynamic parameters, mechanical properties, physiological rules and environmental conditions. In the two-dimensional version presented here, a cell is represented by a closed chain of self-avoiding beads linked together using the bond fluctuation algorithm. The cell is thus controlled both by the rigidity of its membrane and a pressure difference. The model is complemented by key features such as the explicit presence of nutrient diffusion and flow, the processes of cell-division and cell-death, and the attractive interactions between the cell and the surface on which the colony grows. Tuning the parameters of the model can lead to the growth and maturation of various types of biofilms. In this first article, we describe the main properties of a two-dimensional version of the model, and we discuss the extension to three dimensions.