Most animals display one or more body axes, such as the head-to-tail axis, which usually form during early embryogenesis. Such axis formation can be studied in vitro, in stem cell aggregates called gastruloids. While initially isotropic, gastruloids break rotational symmetry over the course of roughly a day, reflected in an asymmetric distribution of cell fates.

We want to understand how cell fate dynamics interacts with cell motion and tissue dynamics.

On this project, we work together with the experimental groups of Pierre-François Lenne (Marseille), Vikas Trivedi (Barcelona), and Verena Ruprecht (Innsbruck).

A key process during animal development is the anisotropic deformation of tissues. Often, such deformation is actively driven and some kind of orientational information is inherently defined within tissues (for instance in terms of cell polarity or cell shape anisotropy). Yet, generic theories for such active materials with orientational information predict inherent instabilities. How could such instabilities be prevented to during animal development? To address this question, we study the interplay between orientational information and tissue mechanics using both cell-based and hydrodynamic models for biological tissues.

Sheet-like biological tissues, called epithelia, are often curved during animal development. How does curvature affect the tissue dynamics? For instance, when tissues change their Gaussian curvature, then they need to deform tangentially. What are the consequences of this for tissue flow?

On this project, we work together with the experimental group of Thomas Lecuit (Marseille).

How do large-scale properties of disordered systems arise from the complex interplay of their microscopic constituents? This question is important to understand a large class of materials both living and non-living. We have recently analytically show that the elastic properties of the broad class of under-constrained materials follows very generic relations. This is relevant to understand systems as diverse as semi-flexible polymer networks like collagen, cell-based vertex models for biological tissue, and membranes.

On this project, we work together with the theory group of Daniel Sussman (Atlanta).