Cells, even in their simplest forms, exhibit adaptive motion and task execution, capabilities underpinned by their complex and hierarchized architecture, and their ability to dissipate energy. Replicating such intricate behavior at the microscale offers a pathway to uncover the fundamental physical and material ingredients required for biological complexity, while also inspiring the design of next-generation synthetic cells [1,2]. In this talk, I will present our approach to active and biomimetic soft matter across two complementary levels of complexity.
First, I will discuss simple active colloids as minimal model systems to design and control behavior in complex environments. We design active colloidal particles with tailored responses to external fields, enabling controlled motility and interactions. We then study how these programmed behaviors are modified by confinement, and crowding to uncover the physical mechanisms governing transport in porous media [3] and the emergence of collective dynamics [4]. Second, I will show how we move from rigid colloids to cell-inspired scaffolds based on giant unilamellar vesicles (GUVs). Compared with conventional active colloids, GUVs combine motility with membrane deformability, compartmentalization, making them particularly relevant as minimal cell models. I will present our recent results on motile GUVs driven out of equilibrium under external actuation, including run-and-tumble-like dynamics linked to membrane properties [5]. These results show how soft, adaptive compartments provide a route toward synthetic systems that not only move, but also display life-inspired shape changes and functions.
1] G.Volpe, N. A. M. Araújo, M. Guix, M. Miodownik, N.Martin, L. Alvarez, et.al., Animated Matter Roadmap (2025)
[2] V. Willems, P. Moreno, J. Fojo, L. Rodriguez-Arco, L.Alvarez. Life-like processes in synthetic protocells under external fields. Newton (2026)
[3] A. Cazorla, M. L. Jiménez Olivares, R. Rica-Alarcón, C. Fernández-Rico, L. Alvarez. Field-programmed dynamical states control active microrod navigation in porous media. Submitted (2026)
[4] L. Alvarez, E. Sensé-Sansa, D. Levis, I. Pagonabarraga, L. Isa. Submitted (2026)
[5] V. Willems, A. Baron, D. A. Matoz-Fernandez, G. Wolfisberg, E. Dufresne, J. C. Baret, and L. Alvarez. Soft Matter (2025).