Swimming bacteria power microspin cycles

Alex E. Hamby, Dhruv K. Vig, Sasha Safonova, Charles William Wolgemuth

Research output: Contribution to journalArticle

Abstract

Dense suspensions of swimming bacteria are living fluids, an archetype of active matter. For example, Bacillus subtilis confined within a disc-shaped region forms a persistent stable vortex that counterrotates at the periphery. Here, we examined Escherichia coli under similar confinement and found that these bacteria, instead, form microspin cycles: a single vortex that periodically reverses direction on time scales of seconds. Using experimental perturbations of the confinement geometry, medium viscosity, bacterial length, density, and chemotaxis pathway, we show that morphological alterations of the bacteria transition a stable vortex into a periodically reversing one. We develop a mathematical model based on single-cell biophysics that quantitatively recreates the dynamics of these vortices and predicts that density gradients power the reversals. Our results define how microbial physics drives the active behavior of dense bacterial suspensions and may allow one to engineer novel micromixers for biomedical and other microfluidic applications.

Original languageEnglish (US)
Article numbereaau0125
JournalScience advances
Volume4
Issue number12
DOIs
StatePublished - Dec 19 2018

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Bacteria
Suspensions
Biophysics
Microfluidics
Physics
Chemotaxis
Bacillus subtilis
Viscosity
Theoretical Models
Escherichia coli
Power (Psychology)
Drive
Direction compound

ASJC Scopus subject areas

  • General

Cite this

Swimming bacteria power microspin cycles. / Hamby, Alex E.; Vig, Dhruv K.; Safonova, Sasha; Wolgemuth, Charles William.

In: Science advances, Vol. 4, No. 12, eaau0125, 19.12.2018.

Research output: Contribution to journalArticle

Hamby, Alex E. ; Vig, Dhruv K. ; Safonova, Sasha ; Wolgemuth, Charles William. / Swimming bacteria power microspin cycles. In: Science advances. 2018 ; Vol. 4, No. 12.
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