Design constraints for morphogenesis and shape-shifting materials

During embryonic development, organisms have an incredible capacity to change their body shape to enable function. We would like to understand how this works, both to address congenital diseases and also to engineer new types of materials with similar functionality. Recent work has shown that rigidity transitions – changing from solid to fluid and back again – are an important tool in the morphogenetic toolbox, much as a skilled glass blower uses heat to partially melt a glass in a controlled way to fashion a glass-blown ornament. In this talk, I will discuss recent advances in theoretical and computational work to understand the space of possible rigidity transitions that can occur in different types of tissues – epithelial tissues that make up the lining of our bodies (skin, gut) as well as mesenchymal tissues that compose the bulk. We can precisely characterize the entire space of possible rigidity transitions in epithelial layers, and we find a surprising new type of behavior – a mix between a fluid and a solid – in mesenchymal tissues. Finally, I will discuss our recent forays into using this understanding as a basis for designing specific material properties and dynamic flows in tissues and materials.