(420c) The Biophysics of Bacterial Biofilms Facilitate Surface Survival in Moving Fluids but May Reveal an Achilles Heel

Bacterial biofilms are microscopic assemblages of bacterial cells usually attached to a surface and held together by a self-produced extracellular polymeric slime (EPS) matrix. Biofilms are ubiquitous in the natural environment and are highly problematic in industry and medicine where they cause corrosion, fouling, contamination and chronic medical and dental infections. The EPS matrix is chemically complex and is composed of polysaccharides, lipids, proteins and DNA and protects the bacteria within from antibiotics chemical challenges and host immunity. Mass transfer through the EPS is dominated by diffusion which, allows the development of gradients in nutrients, waste products and cell signals. The bulk mechanical properties of biofilms play an important role in survival by allowing the biofilm to respond to fluid shear stresses over very short (ms) and very long (days to weeks) time scales. Creep and relaxation tests show that biofilms behave as viscoelastic liquids however and recent observations of high velocity impacts with water droplets suggest they rapidly form interfacial instabilities allowing them to flow over surfaces with velocities of meters per second. Generating turbulence in the biofilm might explain enhanced killing by antimicrobial agents in dental biofilms and have broader applications in biofilm control. A better understanding of how bacterial biofilms respond to fluid flow provides new opportunities to develop more effective control strategies.