title: Formation and post-formation dynamics of bacterial biofilm streamers as highly viscous liquid jets.
abstract: It has been recently reported that in presence of low Reynolds number (Re ≪ 1) transport, preformed bacterial biofilms, several hours after their formation, may degenerate in form of filamentous structures, known as streamers. In this work, we explain that such streamers form as the highly viscous liquid states of the intrinsically viscoelastic biofilms. Such "viscous liquid" state can be hypothesized by noting that the time of appearance of the streamers is substantially larger than the viscoelastic relaxation time scale of the biofilms, and this appearance is explained by the inability of a viscous liquid to withstand external shear. Further, by identifying the post formation dynamics of the streamers as that of a viscous liquid jet in a surrounding flow field, we can interpret several unexplained issues associated with the post-formation dynamics of streamers, such as the clogging of the flow passage or the exponential time growth of streamer dimensions. Overall our manuscript provides a biophysical basis for understanding the evolution of biofilm streamers in creeping flows.
authors.affiliation: Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA.
authors.forename: Siddhartha
authors.initials: S
authors.lastname: Das
authors.affiliation: Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2G8.
authors.forename: Aloke
authors.initials: A
authors.lastname: Kumar
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D004548:Elasticity; D015233:Models, Statistical; D011550:Pseudomonas aeruginosa / Q000737:chemistry / Q000502:physiology*; D011551:Pseudomonas fluorescens / Q000737:chemistry / Q000502:physiology*; D012212:Rheology; D033081:Shear Strength; D013212:Staphylococcus epidermidis / Q000737:chemistry / Q000502:physiology*; D013314:Stress, Mechanical; D014783:Viscosity