Living, Fluid, & Soft Matter

Current Focus

• Swimming dynamics of micro- to mesoscale organisms
• Soft matter mechanics of living materials, such as tiny plant roots and immune cells
• Droplets and capillary phenomena
• Further development of the micropipette force sensor technique

Research Highlights

New papers from the group (group members in bold, † shared 1st authors):

• Living droplets with mesoscale swimmers
  L. Malik†, N. Sharadhi†, M. Lamminmäki, R. A. Lara, V. Jokinen, and M. Backholm*
  arXiv:2509.20005 (2025).
• Ultra-slow capillary rise on hydrogel surfaces
  A. Datar, J. Ryssy, A. O. Toivonen, and M. Backholm*
  arXiv:2509.08331 (2025).
• Forces and symmetry breaking of a living meso-swimmer
  R. A. Lara†, N. Sharadhi†, A. A. L. Huttunen, L. Ansas, E. J. G. Rislakki, G. M. Bessa, and M. Backholm*
  Communications Physics 9, 53(2026). Data shared on Zenodo.
• Soft matter mechanics of immune cell aggregates
  S. Askari†, G. Saldo Rubio†, A. Datar, H. Harjunpää, S. C. Fagerholm*, and M. Backholm*
  J. R. Soc. Interface 22, 20250231 (2025). Data shared on Zenodo.

These papers showcase the PhD and postdoc research of Prof. Backholm:

• Toward vanishing droplet friction on repellent surfaces
  M. Backholm*, T. Kärki, H. Nurmi, M. Vuckovac, V. Turkki, S. Lepikko, V. Jokinen, D. Quéré, J. V. I. Timonen, and R. H. A. Ras*
  Proc. Natl. Acad. Sci. USA (PNAS) 121, e2315214121 (2024). Data shared on Zenodo.
• Droplet slipperiness despite surface heterogeneity at molecular scale
  S. Lepikko, Y. Morais Jaques, M. Junaid, M. Backholm, J. Lahtinen, J. Julin, V. Jokinen, T. Sajavaara, M. Sammalkorpi, A. S. Foster, and R. H. A. Ras
  Nature Chemistry 16, 506-513 (2024).
• Long-term stability of aerophilic metallic surfaces underwater
  A. B. Tesler, S. Kolle, L. H. Prado, I. Thievessen, D. Böhringer, M. Backholm, B. Karunakaran, H. A. Nurmi, M. Latikka, L. Fischer, S. Stafslien, Z. M. Cenev, J. V. I. Timonen, M. Bruns, A. Mazare, U. Lohbauer, S. Virtanen, B. Fabry, P. Schmuki, R. H. A. Ras, J. Aizenberg, and W. H. Goldmann 
  Nature Materials 22, 1548–1555 (2023).
• Water droplet friction and rolling dynamics on superhydrophobic surfaces
  M. Backholm*, D. Molpeceres, M. Vuckovac, H. Nurmi, M. Hokkanen, V. Jokinen, J.V.I. Timonen, and R.H.A. Ras*
  Communications Materials 1, 64(2020).
• Viscosity-enhanced droplet motion in sealed superhydrophobic capillaries
  M. Vuckovac, M. Backholm, J.V.I. Timonen, and R.H.A. Ras
  Science Advances 6, eaba5197 (2020).
  [Highlighted by 12 news outlets, such as Physics Today and Physics World.]
• Micropipette force sensors for in vivo force measurements on single cells and multicellular microorganisms
  M. Backholm*, and O. Bäumchen*
  Nature Protocols 14, 594–615 (2019).
  [Highlighted by 10 news outlets, including Science Daily, Phys.org, EurekAlert, ScienMag, TodayChan, and Göttinger Tageblatt]
• Tangling of tethered swimmers: Interactions between two nematodes
  M. Backholm, R. D. Schulman, W. S. Ryu, and K. Dalnoki-Veress
  Phys. Rev. Lett. 113, 138101 (2014).
  [Editor's Suggestion, Highlighted by PRL Editorial]
• Viscoelastic properties of the nematode Caenorhabditis elegans, a self-similar, shear-thinning worm
  M. Backholm, W. S. Ryu, and K. Dalnoki-Veress
  Proc. Natl. Acad. Sci. USA (PNAS) 110, 4528-4533 (2013).