Modeling and Simulation of the Biomechanics of Biofilms With Heterogeneous Rheological Properties

Jay Stotsky, University of Colorado

In recent years, much work has been done to develop detailed mathematical models that capture the biomechanical response of bacterial biofilms to physical changes. In general, the biomechanical response of a biofilm is dependent on the extra cellular matrix (ECM), a viscous and highly spatially heterogeneous mixture of polysaccharides and other biological products produced by bacteria in the biofilm. I will present details about a new method of simulating biofilms that accounts for both the spatial heterogeneity of the extra-cellular matrix and the viscoelastic connections between bacteria in a biofilm. This method is based on adaptations of the classic Immersed Boundary Method and is denoted as the heterogeneous rheology Immersed Boundary Method (hrIBM). With this extension of the Immersed Boundary Method, biofilms are treated as viscoelastic fluids possessing variable rheological properties anchored to a set of moving locations (i.e., the bacteria locations). Validation results in which dynamic moduli and compliance moduli computed from the model are compared to data from mechanical characterization experiments on Staphylococcus epidermidis biofilms also will be presented.

Abstract Author(s): Jay A. Stotsky, David M. Bortz