Confined Flow: Consequences and Implications for Bacteria and Biofilms

Abstract

Bacteria overwhelmingly live in geometrically confined habitats that feature small pores or cavities, narrow channels, or nearby interfaces. Fluid flows through these confined habitats are ubiquitous in both natural and artificial environments colonized by bacteria. Moreover, these flows occur on time and length scales comparable to those associated with motility of bacteria and with the formation and growth of biofilms, which are surface-associated communities that house the vast majority of bacteria to protect them from host and environmental stresses. This review describes the emerging understanding of how flow near surfaces and within channels and pores alters physical processes that control how bacteria disperse, attach to surfaces, and form biofilms. This understanding will inform the development and deployment of technologies for drug delivery, water treatment, and antifouling coatings and guide the structuring of bacterial consortia for production of chemicals and pharmaceuticals.

Flow States and Transitions of an Active Nematic in a Three-Dimensional Channel

“…Under the right conditions, such systems are capable of self-organization from chaotic flows into coherent flows: groups of active particles move together as a unit in a directed manner [2,[12][13][14]. Coherent active flows are relevant to the formation of bacterial biofilms [15], wound healing [16], organ formation [17], and collective tumor invasion [18]. Beyond the biological implications, understanding how these self-sustained flows can be controlled and directed would prove to be a tremendous advance in microfluidics [19] where, conventionally, external flows are imposed for targeted drug delivery [20], for mixing in microreactors [21], or for pumping fluids at microscales [22].…”

Modeling hydrodynamic interactions in soft materials with multiparticle collision dynamics

“…Motile microorganisms such as protozoa and bacteria are the canonical biological example of active particles. They use appendages known as flagella to swim through fluids [68]. Because of their small size and slow swimming speeds, their HI are described by the linear, inertialess Stokes equations.…”

“…In this regime, swimming motions that are symmetric upon time reversal result in zero net displacement and hence cannot be used to move through the fluid. Consequently, flagellated microorganisms evolved to swim using motions that break time-reversal symmetry [68].…”

Thermodynamic Surface Analyses to Inform Biofilm Resistance

“…The parallel alignment is likely thermodynamically driven, whereas non-parallel alignment is kinetically controlled. The kinetic (i.e., dynamic) component has been modeled using complex algorithms and applied theories to describe bacterial attachment (Conrad and Poling-Skutvik, 2018;McLay et al, 2018;Vissers et al, 2019).…”