Polar jets of swimming bacteria condensed by a patterned liquid crystal

Taras Turiv, Runa Koizumi, Kristian Thijssen, Mikhail M. Genkin, Hao Yu, Chenhui Peng, Qi Huo Wei, Julia M. Yeomans, Igor S. Aranson, Amin Doostmohammadi, Oleg D. Lavrentovich

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


Active matter exhibits remarkable collective behaviour in which flows, continuously generated by active particles, are intertwined with the orientational order of these particles. The relationship remains poorly understood as the activity and order are difficult to control independently. Here we demonstrate important facets of this interplay by exploring the dynamics of swimming bacteria in a liquid crystalline environment with predesigned periodic splay and bend in molecular orientation. The bacteria are expelled from the bend regions and condense into polar jets that propagate and transport cargo unidirectionally along the splay regions. The bacterial jets remain stable even when the local concentration exceeds the threshold of bending instability in a non-patterned system. Collective polar propulsion and the different roles of bend and splay are explained by an advection–diffusion model and by numerical simulations that treat the system as a two-phase active nematic. The ability of prepatterned liquid crystalline medium to streamline the chaotic movements of swimming bacteria into polar jets that can carry cargo along a predesigned trajectory opens the door for potential applications in microscale delivery and soft microrobotics.

Original languageEnglish (US)
Pages (from-to)481-487
Number of pages7
JournalNature Physics
Issue number4
StatePublished - Apr 1 2020

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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