Network patterns in exponentially growing 2D biofilms

TL;DR

This paper demonstrates that physical confinement alone can induce stable pattern formation in 2D biofilms, without the need for growth regulation or differentiation, highlighting a mechanical mechanism behind biofilm patterning.

Contribution

The study introduces a model showing how environmental confinement can cause pattern formation in biofilms independently of biological regulation mechanisms.

Findings

Confinement leads to stable biofilm patterns.

Physical deformation of the environment drives pattern formation.

Patterns emerge without growth regulation or differentiation.

Abstract

Anisotropic collective patterns occur frequently in the morphogenesis of 2D biofilms. These patterns are often attributed to growth regulation mechanisms and differentiation based on gradients of diffusing nutrients and signalling molecules. Here, we employ a model of bacterial growth dynamics to show that even in the absence of growth regulation or differentiation, confinement by an enclosing medium such as agar can itself lead to stable pattern formation over time scales that are employed in experiments. The underlying mechanism relies on path formation through physical deformation of the enclosing environment.