(316b) Invited Speaker: Establishing and Exploiting Biocolloidal Properties of Biofilms

Bacterial biofilms are structured communities of cells encapsulated in matrix materials that include polysaccharides, proteins, and DNA. Studying bacterial biofilms as a soft matter system—where the cells are analogous to colloidal particles and the matrix materials are analogous to viscoelastic hydrogels—allows for relationships between biofilm structure and mechanics to be revealed. Structural and mechanical properties of biofilms are important to nutrient and antimicrobial transport within biofilms, biofilm fragmentation and resilience in fluid flow, and biofilm sociobiology. Here I use a biocolloidal lens to establish the microstructure of staphylococcal biofilms and to demonstrate how bacterial cells and biofilm matrix materials interact to generate biofilm morphology and mechanics. I show that staphylococcal biofilm cellular clustering and separations depend significantly on growth environment, where unstressed staphylococcal biofilms have densely packed, disordered cellular microstructures, and stressed staphylococcal biofilms contain open, tenuous microstructures. Next, artificial biofilms are created with microstructures and mechanical behaviors matching those of natural staphylococcal biofilms. These artificial biofilms are utilized to reveal the importance of pH and matrix interactions to biofilm mechanics. Natural staphylococcal biofilms are then softened through tuning the pH of their microenvironment. Findings from these studies have implications for studying biophysical contributions to staphylococcal biofilm disassembly and dispersion as well as the development of biofilm control strategies targeting matrix interactions.