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Title: Topological defects in a living nematic ensnare swimming bacteria [Linking bacterial motility and liquid crystallinity in a model of living nematic]

Active matter exemplified by suspensions of motile bacteria or synthetic self-propelled particles exhibits a remarkable propensity to self-organization and collective motion. The local input of energy and simple particle interactions often lead to complex emergent behavior manifested by the formation of macroscopic vortices and coherent structures with long-range order. A realization of an active system has been conceived by combining swimming bacteria and a lyotropic liquid crystal. Here, by coupling the well-established and validated model of nematic liquid crystals with the bacterial dynamics, we develop a computational model describing intricate properties of such a living nematic. In faithful agreement with the experiment, the model reproduces the onset of periodic undulation of the director and consequent proliferation of topological defects with the increase in bacterial concentration. It yields a testable prediction on the accumulation of bacteria in the cores of +1/2 topological defects and depletion of bacteria in the cores of -1/2 defects. Our dedicated experiment on motile bacteria suspended in a freestanding liquid crystalline film fully confirms this prediction. Lastly, our findings suggest novel approaches for trapping and transport of bacteria and synthetic swimmers in anisotropic liquids and extend a scope of tools to control and manipulate microscopic objects inmore » active matter.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Northwestern Univ., Evanston, IL (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
  3. Kent State Univ., Kent, OH (United States)
  4. Pennsylvania State Univ., University Park, PA (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Published Article
Journal Name:
Physical Review. X
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2160-3308
Publisher:
American Physical Society
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Materials Sciences and Engineering Division; National Science Foundation (NSF); USDOE
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 36 MATERIALS SCIENCE; 60 APPLIED LIFE SCIENCES; active matter; bacterial motility; liquid crystal; lyotropic
OSTI Identifier:
1346273
Alternate Identifier(s):
OSTI ID: 1362114