Diffusion limited biofilm growth

Abstract

A two-dimensional Monte Carlo-diffusion model is described to model the growthof biofilms of Escherichia coli on different substrates. The modeltakes into account the diffusion rate of the nutrient solution that covers thebiofilm and allows for the bacteria to grow with differing aspect ratios.Parameters are introduced to describe the relative growth and deposition ratesand the amount of curvature of the bacteria over the surface. Limiting casesarise when the diffusion is slow, so that growth near existing bacteria isreduced, and when diffusion is fast, so that the available nutrient is uniformlydistributed over the surface. The results are compared with experimental lightmicroscopy and scanning force microscopy images of E. coli grown on avariety of different substrates. The parameters in the model are adjusted toshow the different growth patterns that can form at different times andcoverages.