Welcome to the Mathijssen Lab @ UPenn!

Exploring the physics of life
DiscoverJoin us

Our mission

The Mathijssen lab is interested in exploring the physics of life: we combine experimental and theoretical techniques across the disciplines of physics and biology.

Our main goals are to unravel the physics of pathogens, to design biomedical materials, and understand the collective functionality of living systems (out of equilibrium). To solve these multi-scale problems we use methods from microbiology, fluid mechanics, omics, statistical physics, microscopy and information theoryRecent themes include hydrodynamic communication, pathogen clearance in the airways, tuning upstream swimming of microrobots, and bacterial contamination dynamics.

These questions are both fundamental in nature (e.g. How can an intelligent system arise from the collective dynamics of its basic components?) and directly applied to our society (e.g. What is the probability of SARS-CoV-2 transmission within a food supply chain?). Our enthusiasm for research is driven by curiosity and the need for solutions that connect science with the challenges of the world we live in. Besides research, we like organising community events, lab visits and science hikes. 

In the News

  • CNN, video demonstration with Coy Wire, Jackie Wattles, and Tiffany Anthony, “Scientifically perfected coffee brew uses less beans for more flavor” (8 May 2025)
  • New York Times, by Katrina Miller, “The Physics of the Perfect Pour Over”, published online (24 Apr) and in print (29 Apr 2025)
  • USA Today, by Elizabeth Weise, “Scientists release instructions for how to make a perfect cup of coffee”, featured on the front page (9 Apr 2025)
  • The Guardian, by Nicola Davis, “Secret to stronger pour-over coffee with no extra beans unlocked by scientists”, published online and in print (8 Apr 2025)
  • New Scientist (UK), by Matthew Sparkes, “How to make great coffee with fewer beans according to science”, published online and in print (8 Apr 2025)
  • Frankfurter Allgemeine Zeitung (German National Newspaper), by Piotr Heller, “Kaffee zu schwach? Physiker haben Tipps”, in German, published online and in print (8 Apr 2025)
  • Physics Magazine, by Katherine Wright, “From Whiskey to Oreos” (15 Jun 2023)
  • Penn Today, by Nathi Magubane, “Exploring the relationship between cooking and scientific discovery” (15 Jun 2023)
  • Scienmag, by Michal Czerepaniak, “Science in the kitchen” (22 Jun 2023)
  • NZZ am Sonntag (Swiss National Newspaper), by Patrick Imhasly, “Fünf Physikkenntnisse, um in der Küche zu punkten”, published online & in print (8 Jul 2023)
  • Times Higher Education, Matthew Reisz, “Physicists break new ground by getting back to the kitchen” (29 Nov 2020)
  • Science Daily, American Physical Society, “Lab closed? Head to the kitchen” (23 Nov 2020)
Culinary Fluid Mechanics

Selected Publications

  • Torres-Maldonado B, Thery A, Tao R, Brosseau Q, Mathijssen* AJTM, Arratia* P, “Enhancement of bacterial rheotaxis in non-Newtonian fluids” Proceedings of the National Academy of Sciences 121 (50) e2417614121 (2024) [10.1073/pnas.2417614121] [download PDF]
  • Park E, Young M, Mathijssen AJTM, “Pour-over coffee: Mixing by a water jet impinging on a granular bed with avalanche dynamics”, Physics of Fluids 37: 043332 (2025) [10.1063/5.0257924] [download PDF]
  • Ramirez-San Juan GR, Mathijssen AJTM, He M, Jan L, Marshall WF, Prakash M, “Multi-scale spatial heterogeneity enhances particle clearance in airway ciliary arrays”, Nature Physics (2020) [10.1038/s41567-020-0923-8] [download PDF]
  • Guzman-Lastra F, Löwen H, Mathijssen AJTM, “Active carpets drive non-equilibrium diffusion and enhanced molecular fluxes”, Nature Communications 12: 1906 (2021) [10.1038/s41467-021-22029-y] [download PDF]
  • Mathijssen AJTM, Culver J, Bhamla MS, Prakash M, “Collective intercellular communication through ultra-fast hydrodynamic trigger waves”, Nature 571: 560 (2019) [10.1038/s41586-019-1387-9] [download PDF]

Visit this page for a full publication list.

Join our team

Scientific innovation depends on the diversity of our team, in my opinion. We welcome people regardless of who they are and where they come from. We support each other’s differences, because everyone has unique talents.

Applications are invited from a broad range of academic backgrounds. We are looking for undergraduate, graduate and postdoctoral researchers interested in (learning) the fields of biological physics, soft matter, physical biology, chemistry, engineering, mathematics and data science. Both experimental and theoretical or computational research positions are currently available: Click here to find out more and join us!

Physics of Us

Community and Events

Left: Illustration by Marina Muun

NEWS: Publication in Nature Machine Intelligence:

Artificial microtubules for rapid and collective transport of magnetic microcargoes

Hongri Gu, Emre Hanedan, Quentin Boehler, Tian-Yun Huang, Arnold J. T. M. Mathijssen & Bradley J. Nelson

NEWS: Editor’s choice paper in Physical Review Letters:

Collective entrainment and confinement amplify transport by schooling micro-swimmers

Chenyu Jin, Yibo Chen, Corinna C. Maass, Arnold J. T. M. Mathijssen

Micro-swimmers can serve as cargo carriers that move deep inside complex flow networks. When a school collectively entrains the surrounding fluid, their transport capacity can be enhanced.

NEWS: Paper published in Nature Communications:

Active carpets drive non-equilibrium diffusion and enhanced molecular fluxes

Francisca Guzmán-Lastra, Hartmut Löwen, Arnold J. T. M. Mathijssen

Fick’s laws describe the essential physics of diffusion, but it is challenging to extend them to systems out of equilibrium. The authors derive the diffusivity of particles near active carpets – a surface covered with hydrodynamic actuators, which provides a framework for transport in living matter.

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“Good nature and good sense must ever join;

To err is human; to forgive, divine.”

— An essay on criticism, Alexander Pope (1688-1744)