Collective functionalities emerging in microbial active matter

by Prof. Arnold Mathijssen (University of Pennsylvania)

Monday 29 May 2023, 16:00 → 17:00 Europe/Rome

Aula Rasetti (Dipartimento di Fisica-Ed. G.Marconi)

Microbes often cooperate to withstand predators and compete even with multicellular organisms. Together, they can achieve functionalities that alone they cannot. However, this puzzle of how biological self-organization emerges from the collective dynamics of individual constituents remains unsolved. In this talk, I will discuss some of these collective functionalities, including communication, navigation, and cooperative nutrient transport. First, we focus on ultra-fast communication through “hydrodynamic trigger waves”, signals between cells that propagate hundreds of times faster than their swimming speed [1]. Second, we will explore how bacteria can reorient against flows and contaminate reservoirs upstream [2]. Third, we consider how bacteria generate their own flows to transport nutrients [3], and how “active carpets” like biofilms can lead to enhanced non-equilibrium diffusion [4]. Together, these ideas help us understand emergent self-organization in biological systems and the design space of active materials.

[1] Mathijssen et al. “Collective intercellular communication through ultra-fast hydrodynamic trigger waves,” Nature 571, 560-564 (2019)
[2] Mathijssen et al. “Oscillatory surface rheotaxis of swimming E. coli bacteria,” Nat. Commun. 10, 3434 (2019)
[3] Jin et al. “Collective entrainment and confinement amplifies transport by schooling micro-swimmers”, Phys. Rev. Lett. 127: 088006 (2021)
[4] Guzman-Lastra et al. “Active carpets drive non-equilibrium diffusion and enhanced molecular fluxes,” Nat. Commun. 12: 1906 (2021)