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par douarche - publié le






Carine Douarche
Eric Raspaud


Bacteria are unicellular prokaryotic microorganisms. They are ubiquitous and constitute a large part of the terrestrial biomass. Bacteria live as individuals interacting with their environment during the planktonic phase but prefer most of the time to self-organize in a collective manner in complex architectures adsorbed on interfaces, the so-called biofilms. During biofilms formation, bacteria produce an extracellular matrix made of macromolecules allowing cohesion in the bacterial community. These biofilms assemble in aqueous environments on solid, inert or living surfaces or at liquid/air interfaces. We started a project to study the elasticity of this material, its dynamics (from the individual cell to the collective movements) and the structuration of the biofilms during their development. Bacteria consume chemical energy to form the colony and they also differentiate within the system. Their states depend on multiple factors like the concentrations of nutrients and oxygen whose spatial and temporal distributions are non homogeneous and vary with time. For these reasons, bacteria in colony like most of living system in nature are examples of non-equilibrium systems. Theroretical aspects of the mechanics and geometry of fluid and elastic membranes are also considered.