Biological tissues as active amorphous solids

Biological tissues share many similarities with traditional amorphous solids, such as foams or dense emulsions (e.g., mayonnaise). Yet unlike passive materials, tissues are living systems where cells grow and actively drive events like divisions and extrusions.
In the first part of the seminar, I will present our recent works on describing tissues as active amorphous solids, where we study how cell divisions contribute to tissue flow and how cell extrusions maintain mechano-sensitive tissue homeostasis. While these processes have been described using fluid-like models, our approach predicts novel, experimentally testable, rheological and statistical properties of biological tissues.
In the second part, I will address the origin of disorder in cellular packings. Using experimental data from fruit fly D. melanogaster developing wing epithelia, we demonstrate that cell-cycle dynamics alone can explain the observed heterogeneity in cell sizes. Furthermore, we show that reducing this heterogeneity can drive tissue crystallization and show that this type of phase transition occurrs at late stages of the fruit fly wing development.