---
OA_place: repository
_id: '21423'
abstract:
- lang: eng
  text: "Biological systems, such as cytoskeletal filaments and multicellular collectives,
    exhibit rich \r\nself-organization driven by their intrinsic activity and physical
    constraints. Across scales, \r\ngeometry plays a central role: the shape of active
    units and the structure of their environment \r\nstrongly influence how order
    emerges in these far-from-equilibrium systems. In this thesis, \r\nwe combine
    minimal active-matter models with bottom-up in vitro experiments to identify \r\nthe
    principles by which geometry and activity shape collective behavior in biological
    matter. \r\nAt the subcellular scale, we investigate how the physical properties
    of chiral FtsZ filaments \r\ngovern their large-scale organization. Using a mesoscopic
    model validated by reconstituted \r\nfilament assays, we show that filament shape,
    intrinsic curvature, and flexibility, together with \r\nactivity-driven straightening,
    determine whether filaments form chiral rings, polar bands, or \r\nnematic-like
    states. Our model shows that small changes in filament mechanics produce large
    \r\nshifts in collective structures, revealing how the geometry of individual
    filaments amplifies \r\nthrough activity to control patterns relevant for bacterial
    cytokinesis. \r\nAt the cellular scale, we examine how geometry of the external
    environment influences \r\ncollective cancer cell migration. Experiments in controlled
    microfabricated obstacle \r\nenvironments demonstrate that geometric disorder
    alone can induce a transition from \r\ncollective to single-cell invasion. A minimal
    model of active particles in disordered geometries \r\nreproduces these effects,
    demonstrating that cell dissemination results both from local \r\ngeometrical
    constraints and a global integration of spatial disorder over time. Surprisingly,
    \r\nthis transition is accompanied by a change in the universality class of interface
    dynamics, \r\nrevealing that cell-environment interactions can shift the collective
    behavior of an invasive \r\nfront purely through mechanics.  \r\nIn the last system,
    we study how cell-intrinsic geometry and chirality affect collective motion \r\nin
    confined and unconfined settings. Using a minimal model inspired by in vitro experiments,
    \r\nwe analyze motile cells that exhibit persistent rotation due to intrinsic
    left-right asymmetry. \r\nIn circular confinement, this simplified chiral model
    reproduces several experimentally \r\nobserved features within specific parameter
    regimes. At high densities in unconfined \r\nenvironments, however, intrinsic
    chirality becomes masked even before the onset of the \r\njamming transition.
    These results show that single-cell geometric asymmetry does not \r\nnecessarily
    translate into large-scale chiral flows, offering new insight into how forces
    and \r\nsymmetries shape collective motion in dense cellular systems. \r\nOverall,
    this work uncovers how geometric constraints – embedded in the intrinsic \r\narchitecture
    of an active filament or encoded in the complexity of a microenvironment \r\ncouple
    to active forces to generate different classes of complex behaviors. "
acknowledged_ssus:
- _id: ScienComp
acknowledgement: "Finally, I gratefully acknowledge funding from the DOC Fellowship
  of the Austrian Academy\r\nof Sciences (OeAW): grant agreement 26360."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Zuzana
  full_name: Dunajova, Zuzana
  id: 4B39F286-F248-11E8-B48F-1D18A9856A87
  last_name: Dunajova
citation:
  ama: Dunajova Z. Geometry-driven self-organization of migrating cells and chiral
    filaments. 2026. doi:<a href="https://doi.org/10.15479/AT-ISTA-21423">10.15479/AT-ISTA-21423</a>
  apa: Dunajova, Z. (2026). <i>Geometry-driven self-organization of migrating cells
    and chiral filaments</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-21423">https://doi.org/10.15479/AT-ISTA-21423</a>
  chicago: Dunajova, Zuzana. “Geometry-Driven Self-Organization of Migrating Cells
    and Chiral Filaments.” Institute of Science and Technology Austria, 2026. <a href="https://doi.org/10.15479/AT-ISTA-21423">https://doi.org/10.15479/AT-ISTA-21423</a>.
  ieee: Z. Dunajova, “Geometry-driven self-organization of migrating cells and chiral
    filaments,” Institute of Science and Technology Austria, 2026.
  ista: Dunajova Z. 2026. Geometry-driven self-organization of migrating cells and
    chiral filaments. Institute of Science and Technology Austria.
  mla: Dunajova, Zuzana. <i>Geometry-Driven Self-Organization of Migrating Cells and
    Chiral Filaments</i>. Institute of Science and Technology Austria, 2026, doi:<a
    href="https://doi.org/10.15479/AT-ISTA-21423">10.15479/AT-ISTA-21423</a>.
  short: Z. Dunajova, Geometry-Driven Self-Organization of Migrating Cells and Chiral
    Filaments, Institute of Science and Technology Austria, 2026.
corr_author: '1'
date_created: 2026-03-11T08:30:49Z
date_published: 2026-03-11T00:00:00Z
date_updated: 2026-10-16T08:12:11Z
day: '11'
ddc:
- '539'
- '570'
degree_awarded: PhD
department:
- _id: GradSch
- _id: EdHa
doi: 10.15479/AT-ISTA-21423
doi_confirm: '1'
file:
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fulldoi: https://doi.org/10.15479/AT-ISTA-21423
has_accepted_license: '1'
language:
- iso: eng
month: '03'
oa: 1
oa_version: Published Version
page: '110'
project:
- _id: 34d75525-11ca-11ed-8bc3-89b6307fee9d
  grant_number: '26360'
  name: Motile active matter models of migrating cells and chiral filaments
publication_identifier:
  isbn:
  - 978-3-99078-076-3
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
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  - id: '13314'
    relation: part_of_dissertation
    status: public
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    relation: research_data
    status: public
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status: public
supervisor:
- first_name: Edouard B
  full_name: Hannezo, Edouard B
  id: 3A9DB764-F248-11E8-B48F-1D18A9856A87
  last_name: Hannezo
  orcid: 0000-0001-6005-1561
title: Geometry-driven self-organization of migrating cells and chiral filaments
tmp:
  image: /images/cc_by_nc_sa.png
  legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
  name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
    BY-NC-SA 4.0)
  short: CC BY-NC-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2026'
...