Hotspots of boundary accumulation: dynamics and statistics of micro-swimmers in flowing films

Arnold J. T. M. Mathijssen, Amin Doostmohammadi, Julia M. Yeomans, Tyler N. Shendruk

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Biological flows over surfaces and interfaces can result in accumulation hotspots or depleted voids of microorganisms in natural environments. Apprehending the mechanisms that lead to such distributions is essential for understanding biofilm initiation. Using a systematic framework, we resolve the dynamics and statistics of swimming microbes within flowing films, considering the impact of confinement through steric and hydrodynamic interactions, flow and motility, along with Brownian and run–tumble fluctuations. Micro-swimmers can be peeled off the solid wall above a critical flow strength. However, the interplay of flow and fluctuations causes organisms to migrate back towards the wall above a secondary critical value. Hence, faster flows may not always be the most efficacious strategy to discourage biofilm initiation. Moreover, we find run–tumble dynamics commonly used by flagellated microbes to be an intrinsically more successful strategy to escape from boundaries than equivalent levels of enhanced Brownian noise in ciliated organisms.
Original languageEnglish
Article number20150936
JournalJournal of the Royal Society, Interface
Issue number115
Early online date1 Feb 2016
Publication statusPublished - 29 Feb 2016


  • micro-swimmer dynamics
  • biological fluid dynamics
  • biofilm initiation
  • biofouling
  • low-Reynolds-number flows

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