A Body Made of Glass

Your body is amazing. Only two cell types contain the complete instruction for its construction, yet the trillions of cells that make up your body have ended up in the right place. Interestingly, this self-organization is governed not only by biochemical signaling but also by collective mechanical interactions between cells. Recent discoveries suggest that such collective interactions cause biological tissues to behave as glassy “living materials” near a fluid-solid transition. But what governs this transition? And is it important for biological function?

In this presentation, Lisa Manning will discuss the latest insights into how cells control the fluid-to-solid transition and thereby influence pattern formation at the scale of tissues and organs. Inspiration is drawn from recent breakthroughs in understanding the glass transition in non-biological materials. Cells cannot control traditional thermodynamic variables like temperature and pressure. Instead, they tune their stickiness and the forces they exert on surfaces or one another. When this tuning goes awry, diseases such as cancer, asthma and congenital malformations can arise. Analyzing the mechanical properties of these living materials may lead to better tools for the diagnosis and treatment of disease.

Manning started her research career in the physics of glasses, i.e., how a disordered group of molecules or particles freezes into a rigid solid at a well-defined temperature. She then turned her attention to morphogenesis, the process by which embryos transform from a spherical egg to a shape we recognize as an insect, plant or mammal. She showed that aspects of this process could be modeled by surface tension in analogy with the description of immiscible liquids. Her most recent work uses ideas from the physics of glasses to describe the mobility of cells organized in sheets and applies them to a broad class of biological tissues, including embryos and cells from asthma patients.