Mechanical modeling of biofilm morphology variation induced by changes in environments and internal stress

In recent years, more and more researchers have revealed the relationship between biofilm growth and the environment from a mechanical perspective, providing us with new insights. In this article, we develop multi-scale agent-based biofilm growth models and simulate biofilm growth dynamics from different size scales and aim to reveal the relationship between biofilm, environment, and internal stress. In the mesoscopic model, the bacterial clusters are treated as particles. The predicted biased growth of biofilm under low nutrient concentration is consistent with the experimental measurement results. Sudden alterations in the nutritional environment can lead to drastic changes in biofilm morphology. In the microscopic model, big particles represent individual cells and small particles represent extracellular polymeric substances (EPSs), which is used to simulate complicated interactions among EPSs and cells in the colloidal biofilm system. Results indicate that the emergence of branching structures can help to reduce internal stress concentration in colonies and have a positive effect on colony expansion. The simulation results of this article not only can deepen our understanding of the interaction between biofilms and environments but also make us learn interactions among different components inside the biofilm.