Biofilm Growth under Elastic Confinement
George T Fortune1, Nuno M Oliveira1,2, Raymond E Goldstein1
1Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom.
Physical Review Letters
|May 16, 2022
Summary
Biofilm growth in confined spaces, like between a surface and elastic sheet, differs from unconfined growth. A new model reveals a self-similar expansion regime leading to a finite maximum radius for these biofilms.
Area of Science:
- Microbiology
- Biophysics
- Materials Science
Background:
- Bacteria form biofilms, surface-attached communities encased in an extracellular matrix.
- Previous studies focused on unconfined biofilm growth, showing exponential radial expansion.
- Confined geometries are more relevant to natural and biomedical settings but are less studied.
Purpose of the Study:
- To investigate biofilm growth in a simple confined geometry: between a solid surface and an elastic sheet.
- To develop a theoretical framework predicting biofilm radial growth rates in confinement.
- To compare theoretical predictions with experimental observations of Bacillus subtilis biofilms.
Main Methods:
- Utilized a poroelastic framework to model biofilm growth dynamics.
- Derived the radial growth rate equation for confined biofilms.
- Experimentally grew Bacillus subtilis biofilms confined by a polydimethylsiloxane elastic sheet.
Main Results:
- Identified a novel self-similar expansion regime for confined biofilms.
- This regime is governed by the Poisson's ratio of the biofilm matrix.
- The model predicts a finite maximum radius for confined biofilms, matching experimental data.
Conclusions:
- Confined biofilm growth exhibits distinct dynamics compared to unconfined growth.
- Poroelasticity and matrix properties significantly influence biofilm expansion limits.
- This study provides a framework for understanding biofilm formation in constrained environments.
