December 16, 2024
Speaker: Dr. Helen Ansell (Emory University)
Title: Tunable rheology in models of dense cellular tissue
Helen Ansell is a theoretical physicist whose work uses theoretical and computational modeling to understand emergent features of soft and biological materials. She is currently a Tarbutton Postdoctoral Fellow at Emory University working with Prof. Daniel Sussman to understand anomalous properties of models of cellular tissues. Previously, Helen was a postdoctoral fellow at Northwestern University with Prof. István Kovács, where she used tools from statistical physics to study cellular-level structural properties of the brain. She earned her PhD in Physics from the University of Pennsylvania in 2021 under the supervision of Prof. Randy Kamien. Her PhD research focused on emergent geometric features of ordered soft materials.
Abstract
Densely packed epithelial tissues exhibit dynamical features analogous to properties of glassy materials. This observation has inspired a host of research using coarse-grained geometric cell models to describe the emergent collective behavior of these tissues. Initial studies of the glassy dynamics of several of these models have revealed anomalous sub-Arrhenius scaling of the relaxation dynamics in parameter regimes relevant to real cells. In this talk, I will discuss our recent work showing that in the 2d Voronoi model this “ultra-strong” behavior corresponds to a regime where the viscosity does not diverge and dynamical heterogeneities are highly suppressed, indicating further deviation from the standard glassforming paradigm. I will also briefly discuss our ongoing work examining the rich nonlinear rheology of the model, including observations of shear jamming. Overall, our results further emphasize the unusual material properties of these models and highlight a need for better understanding of their applicability to real cellular tissue.
SLAAM seminars are online research talks presented by postdoctoral scholars in soft matter, biological physics, and related disciplines. The series aims to provide a forum for a diverse set of stellar speakers early in their careers and opportunities for them to interact with researchers at all career stages. For more information about the SLAAM Seminar, visit sites.google.com/view/slaamseminars/.