Biofilms are colonies of bacteria in which the organisms are immobile and embedded in a sticky, viscous, extracellular matrix of carbohydrate polymers. Bacteria existing in these structures are the most prevalent life form on earth. Typically surface adherent and structurally non-uniform, biofilms arise in natural, industrial and health settings. The biomechanics of biofilms are of fundamental physical science interest because bacterial proliferation from them is triggered by their mechanical rupture, fracture and fragmentation. This rupture involves a complex interplay of molecular and physical interactions, each active on different spatial scales of the biofilm. By integrating modern computational methodologies and resources for simulating the non-equilibrium dynamics of polymers and the multiphase flow of polymeric fluids, the mechanisms for biofilm fragmentation will be identified in this project. The following specific research questions will be addressed: i) How do the biofilm?s biochemical composition and composite-like architecture interact to control the critical stress and strain of fragmentation? ii) How should a physical science based mathematical model of biofilm fragmentation be formulated such that molecular scale microbiology and polymer physics as well as continuum scale variability in mechanical stress and strain all play their necessary roles in fragmentation predictions? iii) What educational agenda should be implemented such that microbiologists and physicians can have a working understanding of the usefulness of first-principles physical science and mathematical modeling techniques?
Answering these questions requires joint effort in applied mathematics, non-equilibrium simulation of polymer dynamics, microbiology, and microscale rheology. Successfully doing so promises to transform the scientific understanding of bacterial biofilms from one based solely on molecular biology to one that comprehensively addresses the joint molecular and physical origins of behavior. In addition to improving understanding of biofilms, the methods developed will themselves represent an advance important to many areas including the broad range of soft materials with non-uniform structure on multiple scales. The broader impact of the work will be to produce new scientific understanding of bacterial biofilms mechanics in natural, industrial and human health applications. This understanding will positively impact applications in these diverse areas and, potentially, new treatments for the wide range of diseases linked to biofilms. This program will also yield broader impacts from its computational and modeling plan as well as its educational plan to introduce physical and mathematical modeling into medical school curricula.
