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Title: Shape control and compartmentalization in active colloidal cells

Small autonomous machines like biological cells or soft robots can convert energy input into control of function and form. It is desired that this behavior emerges spontaneously and can be easily switched over time. For this purpose, in this paper we introduce an active matter system that is loosely inspired by biology and which we term an active colloidal cell. The active colloidal cell consists of a boundary and a fluid interior, both of which are built from identical rotating spinners whose activity creates convective flows. Similarly to biological cell motility, which is driven by cytoskeletal components spread throughout the entire volume of the cell, active colloidal cells are characterized by highly distributed energy conversion. We demonstrate that we can control the shape of the active colloidal cell and drive compartmentalization by varying the details of the boundary (hard vs. flexible) and the character of the spinners (passive vs. active). We report buckling of the boundary controlled by the pattern of boundary activity, as well as formation of core–shell and inverted Janus phase-separated configurations within the active cell interior. As the cell size is increased, the inverted Janus configuration spontaneously breaks its mirror symmetry. The result is a bubble–crescent configuration,more » which alternates between two degenerate states over time and exhibits collective migration of the fluid along the boundary. Finally, our results are obtained using microscopic, non–momentum-conserving Langevin dynamics simulations and verified via a phase-field continuum model coupled to a Navier–Stokes equation.« less
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [5]
  1. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemical Engineering and Biointerfaces Inst.
  2. Pennsylvania State Univ., University Park, PA (United States). Dept. of Chemical Engineering
  3. Pennsylvania State Univ., University Park, PA (United States). Dept. of Chemical Engineering; Univ. of California, San Diego, CA (United States). Dept. of NanoEngineering
  4. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Mechanical Engineering
  5. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemical Engineering and Biointerfaces Inst. and Dept. of Materials Science and Engineering
Publication Date:
Grant/Contract Number:
SC0000989; SC00000989
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 112; Journal Issue: 34; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Univ. of Michigan, Ann Arbor, MI (United States); Pennsylvania State Univ., University Park, PA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 36 MATERIALS SCIENCE; active matter; emergent pattern; confinement; colloids
OSTI Identifier:
1235147
Alternate Identifier(s):
OSTI ID: 1347961