MEAM Seminar: “Mechanics of Active Matter: From Cells to Tissues”

How does living matter acquire its physical form? Living cells and tissues are active materials that generate forces, undergo large deformations, and collectively self-organize into robust structures. Understanding and predicting the mechanics of such active matter, from single cells to multicellular systems, calls for new approaches grounded in mechanics and in close conjunction with biological measurement.

In this talk, I will present work combining continuum-mechanical theory, live imaging, and in situ mechanical measurement toward predictive modeling of active matter. I will begin with experiments revealing nonlinear stiffening at the cell-matrix interface, which motivate continuum theories for active elastomeric materials: a visco-hyperelastic framework for cytoskeletal networks and an active nematic elastomer theory for spontaneous orientational ordering in cell-matrix mixtures. I will then turn to confluent multicellular tissues, where I introduce a graph-based kinematic description of cellular configurations. This representation yields geometric order parameters and a statistical characterization of tissue configurations, providing a common framework that connects in vitro cell monolayers, in silico models, and in vivo embryonic tissues. Because graphs naturally encode the topology and geometry of cellular packings, they also provide the foundation for data-driven predictive models: I will show how this approach enables prediction of glassy dynamics in cell monolayers and, at the whole-embryo scale, prediction of cell behaviors at single-cell resolution during Drosophila development. Together, these efforts move us toward understanding the mechanics of active matter and developing engineering design principles for active, living materials.