---
_id: '13971'
abstract:
- lang: eng
  text: When in equilibrium, thermal forces agitate molecules, which then diffuse,
    collide and bind to form materials. However, the space of accessible structures
    in which micron-scale particles can be organized by thermal forces is limited,
    owing to the slow dynamics and metastable states. Active agents in a passive fluid
    generate forces and flows, forming a bath with active fluctuations. Two unanswered
    questions are whether those active agents can drive the assembly of passive components
    into unconventional states and which material properties they will exhibit. Here
    we show that passive, sticky beads immersed in a bath of swimming Escherichia
    coli bacteria aggregate into unconventional clusters and gels that are controlled
    by the activity of the bath. We observe a slow but persistent rotation of the
    aggregates that originates in the chirality of the E. coli flagella and directs
    aggregation into structures that are not accessible thermally. We elucidate the
    aggregation mechanism with a numerical model of spinning, sticky beads and reproduce
    quantitatively the experimental results. We show that internal activity controls
    the phase diagram and the structure of the aggregates. Overall, our results highlight
    the promising role of active baths in designing the structural and mechanical
    properties of materials with unconventional phases.
acknowledgement: D.G. and J.P. thank E. Krasnopeeva, C. Guet, G. Guessous and T. Hwa
  for providing the E. coli strains. This material is based upon work supported by
  the US Department of Energy under award DE-SC0019769. I.P. acknowledges funding
  by the European Union’s Horizon 2020 research and innovation programme under Marie
  Skłodowska-Curie Grant Agreement No. 101034413. A.Š. acknowledges funding from the
  European Research Council under the European Union’s Horizon 2020 research and innovation
  programme (Grant No. 802960). M.C.U. acknowledges funding from the European Union’s
  Horizon 2020 research and innovation programme under Marie Skłodowska-Curie Grant
  Agreement No. 754411.
article_processing_charge: Yes
article_type: original
author:
- first_name: Daniel
  full_name: Grober, Daniel
  id: abdfc56f-34fb-11ee-bd33-fd766fce5a99
  last_name: Grober
- first_name: Ivan
  full_name: Palaia, Ivan
  id: 9c805cd2-4b75-11ec-a374-db6dd0ed57fa
  last_name: Palaia
  orcid: ' 0000-0002-8843-9485 '
- first_name: Mehmet C
  full_name: Ucar, Mehmet C
  id: 50B2A802-6007-11E9-A42B-EB23E6697425
  last_name: Ucar
  orcid: 0000-0003-0506-4217
- first_name: Edouard B
  full_name: Hannezo, Edouard B
  id: 3A9DB764-F248-11E8-B48F-1D18A9856A87
  last_name: Hannezo
  orcid: 0000-0001-6005-1561
- first_name: Anđela
  full_name: Šarić, Anđela
  id: bf63d406-f056-11eb-b41d-f263a6566d8b
  last_name: Šarić
  orcid: 0000-0002-7854-2139
- first_name: Jérémie A
  full_name: Palacci, Jérémie A
  id: 8fb92548-2b22-11eb-b7c1-a3f0d08d7c7d
  last_name: Palacci
  orcid: 0000-0002-7253-9465
citation:
  ama: Grober D, Palaia I, Ucar MC, Hannezo EB, Šarić A, Palacci JA. Unconventional
    colloidal aggregation in chiral bacterial baths. <i>Nature Physics</i>. 2023;19:1680-1688.
    doi:<a href="https://doi.org/10.1038/s41567-023-02136-x">10.1038/s41567-023-02136-x</a>
  apa: Grober, D., Palaia, I., Ucar, M. C., Hannezo, E. B., Šarić, A., &#38; Palacci,
    J. A. (2023). Unconventional colloidal aggregation in chiral bacterial baths.
    <i>Nature Physics</i>. Springer Nature. <a href="https://doi.org/10.1038/s41567-023-02136-x">https://doi.org/10.1038/s41567-023-02136-x</a>
  chicago: Grober, Daniel, Ivan Palaia, Mehmet C Ucar, Edouard B Hannezo, Anđela Šarić,
    and Jérémie A Palacci. “Unconventional Colloidal Aggregation in Chiral Bacterial
    Baths.” <i>Nature Physics</i>. Springer Nature, 2023. <a href="https://doi.org/10.1038/s41567-023-02136-x">https://doi.org/10.1038/s41567-023-02136-x</a>.
  ieee: D. Grober, I. Palaia, M. C. Ucar, E. B. Hannezo, A. Šarić, and J. A. Palacci,
    “Unconventional colloidal aggregation in chiral bacterial baths,” <i>Nature Physics</i>,
    vol. 19. Springer Nature, pp. 1680–1688, 2023.
  ista: Grober D, Palaia I, Ucar MC, Hannezo EB, Šarić A, Palacci JA. 2023. Unconventional
    colloidal aggregation in chiral bacterial baths. Nature Physics. 19, 1680–1688.
  mla: Grober, Daniel, et al. “Unconventional Colloidal Aggregation in Chiral Bacterial
    Baths.” <i>Nature Physics</i>, vol. 19, Springer Nature, 2023, pp. 1680–88, doi:<a
    href="https://doi.org/10.1038/s41567-023-02136-x">10.1038/s41567-023-02136-x</a>.
  short: D. Grober, I. Palaia, M.C. Ucar, E.B. Hannezo, A. Šarić, J.A. Palacci, Nature
    Physics 19 (2023) 1680–1688.
date_created: 2023-08-06T22:01:11Z
date_published: 2023-11-01T00:00:00Z
date_updated: 2024-01-30T12:26:55Z
day: '01'
ddc:
- '530'
department:
- _id: EdHa
- _id: AnSa
- _id: JePa
doi: 10.1038/s41567-023-02136-x
ec_funded: 1
external_id:
  isi:
  - '001037346400005'
file:
- access_level: open_access
  checksum: 7e282c2ebc0ac82125a04f6b4742d4c1
  content_type: application/pdf
  creator: dernst
  date_created: 2024-01-30T12:26:08Z
  date_updated: 2024-01-30T12:26:08Z
  file_id: '14906'
  file_name: 2023_NaturePhysics_Grober.pdf
  file_size: 6365607
  relation: main_file
  success: 1
file_date_updated: 2024-01-30T12:26:08Z
has_accepted_license: '1'
intvolume: '        19'
isi: 1
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
page: 1680-1688
project:
- _id: fc2ed2f7-9c52-11eb-aca3-c01059dda49c
  call_identifier: H2020
  grant_number: '101034413'
  name: 'IST-BRIDGE: International postdoctoral program'
- _id: eba2549b-77a9-11ec-83b8-a81e493eae4e
  call_identifier: H2020
  grant_number: '802960'
  name: 'Non-Equilibrium Protein Assembly: from Building Blocks to Biological Machines'
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: Nature Physics
publication_identifier:
  eissn:
  - 1745-2481
  issn:
  - 1745-2473
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Unconventional colloidal aggregation in chiral bacterial baths
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 19
year: '2023'
...
---
_id: '12822'
abstract:
- lang: eng
  text: Gears and cogwheels are elemental components of machines. They restrain degrees
    of freedom and channel power into a specified motion. Building and powering small-scale
    cogwheels are key steps toward feasible micro and nanomachinery. Assembly, energy
    injection, and control are, however, a challenge at the microscale. In contrast
    with passive gears, whose function is to transmit torques from one to another,
    interlocking and untethered active gears have the potential to unveil dynamics
    and functions untapped by externally driven mechanisms. Here, it is shown the
    assembly and control of a family of self-spinning cogwheels with varying teeth
    numbers and study the interlocking of multiple cogwheels. The teeth are formed
    by colloidal microswimmers that power the structure. The cogwheels are autonomous
    and active, showing persistent rotation. Leveraging the angular momentum of optical
    vortices, we control the direction of rotation of the cogwheels. The pairs of
    interlocking and active cogwheels that roll over each other in a random walk and
    have curvature-dependent mobility are studied. This behavior is leveraged to self-position
    parts and program microbots, demonstrating the ability to pick up, direct, and
    release a load. The work constitutes a step toward autonomous machinery with external
    control as well as (re)programmable microbots and matter.
acknowledgement: 'Army Research Office. Grant Number: W911NF-20-1-0112'
article_number: '2200129'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Quentin
  full_name: Martinet, Quentin
  id: b37485a8-d343-11eb-a0e9-df8c484ef8ab
  last_name: Martinet
- first_name: Antoine
  full_name: Aubret, Antoine
  last_name: Aubret
- first_name: Jérémie A
  full_name: Palacci, Jérémie A
  id: 8fb92548-2b22-11eb-b7c1-a3f0d08d7c7d
  last_name: Palacci
  orcid: 0000-0002-7253-9465
citation:
  ama: Martinet Q, Aubret A, Palacci JA. Rotation control, interlocking, and self‐positioning
    of active cogwheels. <i>Advanced Intelligent Systems</i>. 2023;5(1). doi:<a href="https://doi.org/10.1002/aisy.202200129">10.1002/aisy.202200129</a>
  apa: Martinet, Q., Aubret, A., &#38; Palacci, J. A. (2023). Rotation control, interlocking,
    and self‐positioning of active cogwheels. <i>Advanced Intelligent Systems</i>.
    Wiley. <a href="https://doi.org/10.1002/aisy.202200129">https://doi.org/10.1002/aisy.202200129</a>
  chicago: Martinet, Quentin, Antoine Aubret, and Jérémie A Palacci. “Rotation Control,
    Interlocking, and Self‐positioning of Active Cogwheels.” <i>Advanced Intelligent
    Systems</i>. Wiley, 2023. <a href="https://doi.org/10.1002/aisy.202200129">https://doi.org/10.1002/aisy.202200129</a>.
  ieee: Q. Martinet, A. Aubret, and J. A. Palacci, “Rotation control, interlocking,
    and self‐positioning of active cogwheels,” <i>Advanced Intelligent Systems</i>,
    vol. 5, no. 1. Wiley, 2023.
  ista: Martinet Q, Aubret A, Palacci JA. 2023. Rotation control, interlocking, and
    self‐positioning of active cogwheels. Advanced Intelligent Systems. 5(1), 2200129.
  mla: Martinet, Quentin, et al. “Rotation Control, Interlocking, and Self‐positioning
    of Active Cogwheels.” <i>Advanced Intelligent Systems</i>, vol. 5, no. 1, 2200129,
    Wiley, 2023, doi:<a href="https://doi.org/10.1002/aisy.202200129">10.1002/aisy.202200129</a>.
  short: Q. Martinet, A. Aubret, J.A. Palacci, Advanced Intelligent Systems 5 (2023).
date_created: 2023-04-12T08:30:03Z
date_published: 2023-01-01T00:00:00Z
date_updated: 2023-08-01T14:06:50Z
day: '01'
ddc:
- '530'
department:
- _id: JePa
doi: 10.1002/aisy.202200129
external_id:
  arxiv:
  - '2201.03333'
  isi:
  - '000852291200001'
file:
- access_level: open_access
  checksum: d48fc41d39892e7fa0d44cb352dd46aa
  content_type: application/pdf
  creator: dernst
  date_created: 2023-04-17T06:44:17Z
  date_updated: 2023-04-17T06:44:17Z
  file_id: '12840'
  file_name: 2023_AdvancedIntelligentSystems_Martinet.pdf
  file_size: 2414125
  relation: main_file
  success: 1
file_date_updated: 2023-04-17T06:44:17Z
has_accepted_license: '1'
intvolume: '         5'
isi: 1
issue: '1'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
publication: Advanced Intelligent Systems
publication_identifier:
  issn:
  - 2640-4567
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: Rotation control, interlocking, and self‐positioning of active cogwheels
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 5
year: '2023'
...
---
_id: '11996'
abstract:
- lang: eng
  text: If you mix fruit syrups with alcohol to make a schnapps, the two liquids will
    remain perfectly blended forever. But if you mix oil with vinegar to make a vinaigrette,
    the oil and vinegar will soon separate back into their previous selves. Such liquid-liquid
    phase separation is a thermodynamically driven phenomenon and plays an important
    role in many biological processes (1). Although energy injection at the macroscale
    can reverse the phase separation—a strong shake is the normal response to a separated
    vinaigrette—little is known about the effect of energy added at the microscopic
    level on phase separation. This fundamental question has deep ramifications, notably
    in biology, because active processes also make the interior of a living cell different
    from a dead one. On page 768 of this issue, Adkins et al. (2) examine how mechanical
    activity at the microscopic scale affects liquid-liquid phase separation and allows
    liquids to climb surfaces.
article_processing_charge: No
article_type: letter_note
author:
- first_name: Jérémie A
  full_name: Palacci, Jérémie A
  id: 8fb92548-2b22-11eb-b7c1-a3f0d08d7c7d
  last_name: Palacci
  orcid: 0000-0002-7253-9465
citation:
  ama: Palacci JA. A soft active matter that can climb walls. <i>Science</i>. 2022;377(6607):710-711.
    doi:<a href="https://doi.org/10.1126/science.adc9202">10.1126/science.adc9202</a>
  apa: Palacci, J. A. (2022). A soft active matter that can climb walls. <i>Science</i>.
    American Association for the Advancement of Science. <a href="https://doi.org/10.1126/science.adc9202">https://doi.org/10.1126/science.adc9202</a>
  chicago: Palacci, Jérémie A. “A Soft Active Matter That Can Climb Walls.” <i>Science</i>.
    American Association for the Advancement of Science, 2022. <a href="https://doi.org/10.1126/science.adc9202">https://doi.org/10.1126/science.adc9202</a>.
  ieee: J. A. Palacci, “A soft active matter that can climb walls,” <i>Science</i>,
    vol. 377, no. 6607. American Association for the Advancement of Science, pp. 710–711,
    2022.
  ista: Palacci JA. 2022. A soft active matter that can climb walls. Science. 377(6607),
    710–711.
  mla: Palacci, Jérémie A. “A Soft Active Matter That Can Climb Walls.” <i>Science</i>,
    vol. 377, no. 6607, American Association for the Advancement of Science, 2022,
    pp. 710–11, doi:<a href="https://doi.org/10.1126/science.adc9202">10.1126/science.adc9202</a>.
  short: J.A. Palacci, Science 377 (2022) 710–711.
date_created: 2022-08-28T22:02:00Z
date_published: 2022-08-12T00:00:00Z
date_updated: 2022-09-05T07:37:37Z
day: '12'
department:
- _id: JePa
doi: 10.1126/science.adc9202
external_id:
  pmid:
  - '35951689 '
intvolume: '       377'
issue: '6607'
language:
- iso: eng
month: '08'
oa_version: None
page: 710-711
pmid: 1
publication: Science
publication_identifier:
  eissn:
  - 1095-9203
  issn:
  - 0036-8075
publication_status: published
publisher: American Association for the Advancement of Science
quality_controlled: '1'
scopus_import: '1'
status: public
title: A soft active matter that can climb walls
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 377
year: '2022'
...
---
_id: '10280'
abstract:
- lang: eng
  text: 'Machines enabled the Industrial Revolution and are central to modern technological
    progress: A machine’s parts transmit forces, motion, and energy to one another
    in a predetermined manner. Today’s engineering frontier, building artificial micromachines
    that emulate the biological machinery of living organisms, requires faithful assembly
    and energy consumption at the microscale. Here, we demonstrate the programmable
    assembly of active particles into autonomous metamachines using optical templates.
    Metamachines, or machines made of machines, are stable, mobile and autonomous
    architectures, whose dynamics stems from the geometry. We use the interplay between
    anisotropic force generation of the active colloids with the control of their
    orientation by local geometry. This allows autonomous reprogramming of active
    particles of the metamachines to achieve multiple functions. It permits the modular
    assembly of metamachines by fusion, reconfiguration of metamachines and, we anticipate,
    a shift in focus of self-assembly towards active matter and reprogrammable materials.'
acknowledgement: The authors thank R. Jazzar for useful advice regarding the synthesis
  of heterodimers. We thank S. Sacanna for critical reading. This material is based
  upon work supported by the National Science Foundation under Grant No. DMR-1554724
  and Department of Army Research under grant W911NF-20-1-0112.
article_number: '6398'
article_processing_charge: Yes
article_type: original
author:
- first_name: Antoine
  full_name: Aubret, Antoine
  last_name: Aubret
- first_name: Quentin
  full_name: Martinet, Quentin
  id: b37485a8-d343-11eb-a0e9-df8c484ef8ab
  last_name: Martinet
  orcid: 0000-0002-2916-6632
- first_name: Jérémie A
  full_name: Palacci, Jérémie A
  id: 8fb92548-2b22-11eb-b7c1-a3f0d08d7c7d
  last_name: Palacci
  orcid: 0000-0002-7253-9465
citation:
  ama: Aubret A, Martinet Q, Palacci JA. Metamachines of pluripotent colloids. <i>Nature
    Communications</i>. 2021;12(1). doi:<a href="https://doi.org/10.1038/s41467-021-26699-6">10.1038/s41467-021-26699-6</a>
  apa: Aubret, A., Martinet, Q., &#38; Palacci, J. A. (2021). Metamachines of pluripotent
    colloids. <i>Nature Communications</i>. Springer Nature. <a href="https://doi.org/10.1038/s41467-021-26699-6">https://doi.org/10.1038/s41467-021-26699-6</a>
  chicago: Aubret, Antoine, Quentin Martinet, and Jérémie A Palacci. “Metamachines
    of Pluripotent Colloids.” <i>Nature Communications</i>. Springer Nature, 2021.
    <a href="https://doi.org/10.1038/s41467-021-26699-6">https://doi.org/10.1038/s41467-021-26699-6</a>.
  ieee: A. Aubret, Q. Martinet, and J. A. Palacci, “Metamachines of pluripotent colloids,”
    <i>Nature Communications</i>, vol. 12, no. 1. Springer Nature, 2021.
  ista: Aubret A, Martinet Q, Palacci JA. 2021. Metamachines of pluripotent colloids.
    Nature Communications. 12(1), 6398.
  mla: Aubret, Antoine, et al. “Metamachines of Pluripotent Colloids.” <i>Nature Communications</i>,
    vol. 12, no. 1, 6398, Springer Nature, 2021, doi:<a href="https://doi.org/10.1038/s41467-021-26699-6">10.1038/s41467-021-26699-6</a>.
  short: A. Aubret, Q. Martinet, J.A. Palacci, Nature Communications 12 (2021).
date_created: 2021-11-14T23:01:23Z
date_published: 2021-11-04T00:00:00Z
date_updated: 2023-08-14T11:48:37Z
day: '04'
ddc:
- '530'
department:
- _id: JePa
doi: 10.1038/s41467-021-26699-6
external_id:
  isi:
  - '000714754400010'
  pmid:
  - '34737315'
file:
- access_level: open_access
  checksum: 1c392b12b9b7b615d422d9fabe19cdb9
  content_type: application/pdf
  creator: cchlebak
  date_created: 2021-11-15T13:25:52Z
  date_updated: 2021-11-15T13:25:52Z
  file_id: '10292'
  file_name: 2021_NatComm_Aubret.pdf
  file_size: 6282703
  relation: main_file
  success: 1
file_date_updated: 2021-11-15T13:25:52Z
has_accepted_license: '1'
intvolume: '        12'
isi: 1
issue: '1'
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
pmid: 1
publication: Nature Communications
publication_identifier:
  eissn:
  - 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Metamachines of pluripotent colloids
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 12
year: '2021'
...
