Mesoscale Elucidation of Biofilm Shear Behavior

TL;DR

This study presents a mesoscale model to analyze biofilm shear behavior, revealing strain stiffening, localization, and rupture effects that influence biofilm mechanics and intercellular interactions.

Contribution

The paper introduces a novel mesoscale digitized model of biofilm microstructure to analyze its shear response, highlighting mechanisms like strain stiffening and rupture.

Findings

Strain stiffening occurs under high shear loads.

Shear loading causes strain localization along diagonals.

Polymeric matrix rupture reduces intercellular interactions.

Abstract

Formation of bacterial colonies as biofilm on the surface/interface of various objects has the potential to impact not only human health and disease but also energy and environmental considerations. Biofilms can be regarded as soft materials, and comprehension of their shear response to external forces is a key element to the fundamental understanding. A mesoscale model has been presented in this article based on digitization of a biofilm microstructure. Its response under externally applied shear load is analyzed. Strain stiffening type behavior is readily observed under high strain loads due to the unfolding of chains within soft polymeric substrate. Sustained shear loading of the biofilm network results in strain localization along the diagonal direction. Rupture of the soft polymeric matrix can potentially reduce the intercellular interaction between the bacterial cells. Evolution of stiffness within the biofilm network under shear reveals two regions: a) initial increase in stiffness due to strain stiffening of polymer matrix, and b) eventual reduction in stiffness because of tear in polymeric substrate.