Physics of bacterial
biofilm formation
Most of our knowledge of bacteria comes from studies of independent free-swimming cells. Yet, it is now estimated that 90% of all bacteria on earth exist within biofilms, structured and self-organized communities of non-motile cells.
Compared to freely-swimming cells, bacteria within biofilms adopt a radically distinct ‘lifestyle’, demonstrating profound changes in phenotype, gene expression, and protein production. Cells in a biofilm synthesize a protective and stabilizing matrix that forms an entangled polymer network. This matrix offers the encapsulated cells protection against hostile environmental elements, such as the host immune response, hydrodynamic shear forces, and antimicrobial agents. Impressively, cells in a biofilm are up to 1000 times more tolerant to antibiotics than individual cells. Biofilms thus carry a significant medical burden: approximately 80% of microbial infections are caused by biofilms, and such infections are incredibly difficult to eradicate.
We aim to unveil the physical mechanisms that drive biofilm formation in a myriad of diverse micro-environments. Under the current paradigm, the first step of biofilm formation involves an individual swimming bacterium settling upon, the 'sensing' the surface, triggering the subsequent change in lifestyle. This very first step, the nucleation event, remains poorly understood. Using physics-based approaches, we aim to image biofilm nucleation events with high resolution, capturing the physiological response to surface adhesion at the single cell level. We're also interested in probing biofilm nucleation in unconventional yet medically relevant micro-environments, such as in bulk liquid, at the liquid-air interface, and even in respiratory aerosols.