Rheology of Pseudomonas fluorescens biofilms: from experiments to DPD mesoscopic modelling

TL;DR

This study combines experimental rheology and mesoscopic DPD modeling to analyze the viscoelastic properties of Pseudomonas fluorescens biofilms, providing insights into their structure-function relationship.

Contribution

It introduces a coarse-grain DPD model for bacterial biofilms that accurately predicts rheological behavior and matches experimental data.

Findings

Model reproduces experimental viscoelastic moduli

Topology and composition influence biofilm rheology

Model aids in understanding biofilm mechanics

Abstract

The presence of bacterial biofilms in clinical and industrial settings is a major issue worldwide. A biofilm is a viscoelastic matrix, composed of bacteria producing a network of Extracellular Polymeric Substances (EPS) to which bacteria crosslink. Modelling of complex biofilms is relevant to provide accurate descriptions and predictions that include parameters as hydrodynamics, dynamics of the bacterial population and solute mass transport. However, up-to-date numerical modelling, even at a coarse-grained level, is not satisfactorily. In this work, we present a numerical coarse-grain model of a bacterial biofilm, consisting of bacteria immersed in an aqueous matrix of a polymer network, that allows to study rheological properties of a biofilm. We study its viscoelastic modulus, varying topology and composition (such as the number of crosslinks between EPS polymers, the number of bacteria and the amount of solvent), and compare the numerical results with experimental rheological data of Pseudomonas fluorescens biofilms grown under static and shaking conditions, as previously described by Jara et al, Frontiers in Microbiology (2021).