- Physical Review Journals
All JournalsPhysics Magazine

Physical Review Letters

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Open Access

Wall Torque Controls Propulsion of Curved Microstructures in Bacterial Baths

Nicola Pellicciotta1,2, Ojus Satish Bagal2, Maria Cristina Cannarsa2, Silvio Bianchi1,2, and Roberto Di Leonardo2,1

PDF

Phys. Rev. Lett. 135, 138302 – Published 25 September, 2025

DOI: https://doi.org/10.1103/pnjv-6n5r

Abstract

The persistent dynamics of active particles makes them explore extended portions of an obstacle’s boundary during collisions. From impact to escape, the net applied forces depend on the curvature of the wall and increase in the presence of concave features. Here we systematically investigate the forces exerted by swimming bacteria on microfabricated structures, where the radii of curvature can be varied parametrically. We find that these microsails are propelled with a speed that scales linearly with curvature and is directed from concave to convex side along the axis of symmetry. By solving the collision problem for microswimmers subject to aligning torques at the wall, we show that, despite bacteria rapidly aligning with the surface plane, the resulting force law reduces to that of spherical active particles, with the wall-induced reorientation rate effectively replacing rotational diffusion.

View figure in article

Physics Subject Headings (PhySH)

Article Text

Supplemental Material

References (47)

  1. S. C. Takatori, W. Yan, and J. F. Brady, Swim pressure: Stress generation in active matter, Phys. Rev. Lett. 113, 028103 (2014).
  2. A. P. Solon, Y. Fily, A. Baskaran, M. E. Cates, Y. Kafri, M. Kardar, and J. Tailleur, Pressure is not a state function for generic active fluids, Nat. Phys. 11, 673 (2015).
  3. S. Das, G. Gompper, and R. G. Winkler, Local stress and pressure in an inhomogeneous system of spherical active Brownian particles, Sci. Rep. 9, 6608 (2019).
  4. W. Yan and J. F. Brady, The force on a boundary in active matter, J. Fluid Mech. 785, R1 (2015).
  5. N. Koumakis, A. Lepore, C. Maggi, and R. Di Leonardo, Targeted delivery of colloids by swimming bacteria, Nat. Commun. 4, 2588 (2013).
  6. J. Palacci, S. Sacanna, A. Vatchinsky, P. M. Chaikin, and D. J. Pine, Photoactivated colloidal dockers for cargo transportation, J. Am. Chem. Soc. 135, 15978 (2013).
  7. N. Pellicciotta, O. S. Bagal, V. C. Sosa, G. Frangipane, G. Vizsnyiczai, and R. D. Leonardo, Light controlled biohybrid microbots, Adv. Funct. Mater. 33, 2214801 (2023).
  8. A. Kaiser, A. Peshkov, A. Sokolov, B. ten Hagen, H. Löwen, and I. S. Aranson, Transport powered by bacterial turbulence, Phys. Rev. Lett. 112, 158101 (2014).
  9. N. Pellicciotta, M. Paoluzzi, D. Buonomo, G. Frangipane, L. Angelani, and R. Di Leonardo, Colloidal transport by light induced gradients of active pressure, Nat. Commun. 14, 4191 (2023).
  10. L. Angelani and R. Di Leonardo, Geometrically biased random walks in bacteria-driven micro-shuttles, New J. Phys. 12, 113017 (2010).
  11. R. Di Leonardo, L. Angelani, D. Dell’Arciprete, G. Ruocco, V. Iebba, S. Schippa, M. P. Conte, F. Mecarini, F. De Angelis, and E. Di Fabrizio, Bacterial ratchet motors, Proc. Natl. Acad. Sci. U.S.A. 107, 9541 (2010).
  12. A. Sokolov, M. M. Apodaca, B. A. Grzybowski, and I. S. Aranson, Swimming bacteria power microscopic gears, Proc. Natl. Acad. Sci. U.S.A. 107, 969 (2010).
  13. G. Vizsnyiczai, G. Frangipane, C. Maggi, F. Saglimbeni, S. Bianchi, and R. Di Leonardo, Light controlled 3d micromotors powered by bacteria, Nat. Commun. 8, 15974 (2017).
  14. A. Kaiser, H. H. Wensink, and H. Löwen, How to capture active particles, Phys. Rev. Lett. 108, 268307 (2012).
  15. Y. Fily, A. Baskaran, and M. F. Hagan, Dynamics of self-propelled particles under strong confinement, Soft Matter 10, 5609 (2014).
  16. F. Smallenburg and H. Löwen, Swim pressure on walls with curves and corners, Phys. Rev. E 92, 032304 (2015).
  17. N. Nikola, A. P. Solon, Y. Kafri, M. Kardar, J. Tailleur, and R. Voituriez, Active particles with soft and curved walls: Equation of state, ratchets, and instabilities, Phys. Rev. Lett. 117, 098001 (2016).
  18. S. A. Mallory, C. Valeriani, and A. Cacciuto, Curvature-induced activation of a passive tracer in an active bath, Phys. Rev. E 90, 032309 (2014).
  19. W. Yan and J. F. Brady, The curved kinetic boundary layer of active matter, Soft Matter 14, 279 (2018).
  20. A. Duzgun and J. V. Selinger, Active Brownian particles near straight or curved walls: Pressure and boundary layers, Phys. Rev. E 97, 032606 (2018).
  21. Y. B. Dor, Y. Kafri, M. Kardar, and J. Tailleur, Passive objects in confined active fluids: A localization transition, Phys. Rev. E 106, 044604 (2022).
  22. S. Das, A. Garg, A. I. Campbell, J. Howse, A. Sen, D. Velegol, R. Golestanian, and S. J. Ebbens, Boundaries can steer active Janus spheres, Nat. Commun. 6, 8999 (2015).
  23. J. Simmchen, J. Katuri, W. E. Uspal, M. N. Popescu, M. Tasinkevych, and S. Sánchez, Topographical pathways guide chemical microswimmers, Nat. Commun. 7, 10598 (2016).
  24. A. I. Campbell, S. J. Ebbens, P. Illien, and R. Golestanian, Experimental observation of flow fields around active Janus spheres, Nat. Commun. 10, 3952 (2019).
  25. A. Rashidi, S. Razavi, and C. L. Wirth, Influence of cap weight on the motion of a Janus particle very near a wall, Phys. Rev. E 101, 042606 (2020).
  26. A. Fins Carreira, A. Wysocki, C. Ybert, M. Leocmach, H. Rieger, and C. Cottin-Bizonne, How to steer active colloids up a vertical wall, Nat. Commun. 15, 1710 (2024).
  27. S. Bianchi, F. Saglimbeni, and R. Di Leonardo, Holographic imaging reveals the mechanism of wall entrapment in swimming bacteria, Phys. Rev. X 7, 011010 (2017).
  28. E. Lauga and T. R. Powers, The hydrodynamics of swimming microorganisms, Rep. Prog. Phys. 72, 096601 (2009).
  29. C. Bechinger, R. Di Leonardo, H. Löwen, C. Reichhardt, G. Volpe, and G. Volpe, Active particles in complex and crowded environments, Rev. Mod. Phys. 88, 045006 (2016).
  30. S. Maruo and J. T. Fourkas, Recent progress in multiphoton microfabrication, Laser Photonics Rev. 2, 100 (2008).
  31. S. J. Park, H. Bae, J. Kim, B. Lim, J. Park, and S. Park, Motility enhancement of bacteria actuated microstructures using selective bacteria adhesion, Lab Chip 10, 1706 (2010).
  32. See Supplemental Material at http://link.aps.org/supplemental/10.1103/pnjv-6n5r for experimental and simulation methods, theoretical derivations supporting the findings, and supplemental images, including Refs. [33–36].
  33. V. Linder, B. D. Gates, D. Ryan, B. A. Parviz, and G. M. Whitesides, Water-soluble sacrificial layers for surface micromachining, Small 1, 730 (2005).
  34. F. Walther, P. Davydovskaya, S. Zürcher, M. Kaiser, H. Herberg, A. M. Gigler, and R. W. Stark, Stability of the hydrophilic behavior of oxygen plasma activated SU-8, J. Micromech. Microeng. 17, 524 (2007).
  35. K. A. Datsenko and B. L. Wanner, One-step inactivation of chromosomal genes in Escherichia coli K-12 using PCR products, Proc. Natl. Acad. Sci. U.S.A. 97, 6640 (2000).
  36. S. Kim and S. J. Karrila, Microhydrodynamics: Principles and Selected Applications (Butterworth-Heinemann, Mineola, 2013).
  37. V. A. Martinez, R. Besseling, O. A. Croze, J. Tailleur, M. Reufer, J. Schwarz-Linek, L. G. Wilson, M. A. Bees, and W. C. Poon, Differential dynamic microscopy: A high-throughput method for characterizing the motility of microorganisms, Biophys. J. 103, 1637 (2012).
  38. H. Flyvbjerg and H. G. Petersen, Error estimates on averages of correlated data, J. Chem. Phys. 91, 461 (1989).
  39. E. Lauga, W. R. DiLuzio, G. M. Whitesides, and H. A. Stone, Swimming in circles: Motion of bacteria near solid boundaries, Biophys. J. 90, 400 (2006).
  40. O. Sipos, K. Nagy, R. Di Leonardo, and P. Galajda, Hydrodynamic trapping of swimming bacteria by convex walls, Phys. Rev. Lett. 114, 258104 (2015).
  41. S. Kamdar, D. Ghosh, W. Lee, M. Tătulea-Codrean, Y. Kim, S. Ghosh, Y. Kim, T. Cheepuru, E. Lauga, S. Lim et al., Multiflagellarity leads to the size-independent swimming speed of peritrichous bacteria, Proc. Natl. Acad. Sci. U.S.A. 120, e2310952120 (2023).
  42. E. Pirhadi, X. Cheng, and X. Yong, Dependency of active pressure and equation of state on stiffness of wall, Sci. Rep. 11, 22204 (2021).
  43. H. H. Wensink and H. Löwen, Aggregation of self-propelled colloidal rods near confining walls, Phys. Rev. E 78, 031409 (2008).
  44. V. Kantsler, J. Dunkel, M. Polin, and R. E. Goldstein, Ciliary contact interactions dominate surface scattering of swimming eukaryotes, Proc. Natl. Acad. Sci. U.S.A. 110, 1187 (2013).
  45. R. Di Leonardo, A. Búzás, L. Kelemen, D. Tóth, S. Tóth, P. Ormos, and G. Vizsnyiczai, Boundary shape engineering for the spatial control of confined active particles, arXiv:2410.01916.
  46. G. Volpe et al., Roadmap for animate matter, J. Phys. Condens. Matter 37, 333501 (2025).
  47. N. Pellicciotta, O. Bagal, M. C. Cannarsa, S. Bianchi, and R. Di Leonardo, Dataset of Wall torque controls propulsion of curved microstructures in bacterial baths (Version version1) [Data set] (2025)10.5281/zenodo.16792965.

Outline

Information

Phys. Rev. Lett. 135, 138302– Published 25 September, 2025
  • Received 16 January 2025
  • Revised 4 July 2025
  • Accepted 1 August 2025
Crossmark - Check for updates button
Creative Commons Logo

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation