Dapeng 'Max" Bi, Department of Physics, Syracuse University. Professor Eun-Ah Kim, host.

Seminar Title: Dynamical arrest of cell motion in tissues: a constant-density rigidity transition

Abstract: For important biological functions such as wound healing, embryonic development, and cancer tumorogenesis, cells must initially rearrange and move over relatively large distances, like a liquid. Subsequently, these same tissues must undergo buckling and support shear stresses, like a solid. Our work suggests that biological tissues can accommodate these disparate requirements because the tissues are close to glass or jamming transition. While recent self propelled particle models generically predict a glass/jamming transition that is driven by packing density φ and happens at some critical φc < 1, many confluent biological tissues appear to undergo a jamming transition at a constant density (φ = 1). I will discuss a new theoretical framework for predicting energy barriers and rates of cell migration in 2D tissue monolayers, and show that this model predicts a novel type of jamming transition, which takes place at constant φ = 1 and depends only on single cell properties such as cell-cell adhesion, cortical tension and cell elasticity. I will discuss the implications of these ideas for understanding cancer tumor boundaries and metastasis and pattern formation during development.