Differential growth of wrinkled biofilms

Abstract

Biofilms are antibiotic-resistant bacterial aggregates that grow on moist surfaces and can trigger hospitalacquired infections. They provide a classical example in biology where the dynamics of cellular communities may be observed and studied. Gene expression regulates cell division and differentiation, which affect the biofilm architecture. Mechanical and chemical processes shape the resulting structure. We gain insight into the interplay between cellular and mechanical processes during biofilm development on air-agar interfaces by means of a hybrid model. Cellular behavior is governed by stochastic rules informed by a cascade of concentration fields for nutrients, waste, and autoinducers. Cellular differentiation and death alter the structure and the mechanical properties of the biofilm, which is deformed according to Föppl-Von Kármán equations informed by cellular processes and the interaction with the substratum. Stiffness gradients due to growth and swelling produce wrinkle branching. We are able to reproduce wrinkled structures often formed by biofilms on air-agar interfaces, as well as spatial distributions of differentiated cells commonly observed with B. subtilis.

A three-step framework for programming pattern formation

“…Therefore some have suggested that patterning mechanisms do not act alone but that hybrid mechanisms are more likely to be actually found in nature [55]. One example of this is the formation of biofilm structures [56,57]. The mechanism is highly multidimensional and combines many -if not all -of the mechanisms we have presented here for pattern formation.…”

Self-Supported Crack-Free Conducting Polymer Films with Stabilized Wrinkling Patterns and Their Applications

“…This simple versatile stabilizing strategy is highly expected to other systems for the controlled fabrication of patterned self-supported crack-free films with desirable functions and unprecedented applications. Additionally, the stable wrinkling patterns are obtained through the similar approach in the living systems, in which cell division and differentiation generate and modulate internal stresses to form stabilized hierarchical patterns57, such as fingerprints and the topological conformation of some fruits. Our system might serve as a model system to understand the formation of complex multi-scale micro-textures of biofilms on various substrates, in which the similar stabilizing effect may be involved5859.…”

The Effect of Cell Death on the Stability of a Growing Biofilm

“…Biofilm models incorporating additional biological (in particular the role of EPS [18]) and mechanical processes, following similar approaches as explored in e.g. [15,33], may provide a complementary understanding of biofilm pattern formation.…”