Coming up next
2026-07-09 - 13:30 @ DM 1.09 Gorleaus
SLAM seminar: Paulo C. Godolphim
Tissue Mechanics via the Vertex Model: From Stress Tensors and Parametric Degeneracy to Force Inference in Living Embryos
Abstract
Mechanical stresses are fundamental regulators of biological tissues, where the Vertex Model (VM) has become a central framework for theoretical and force-inference studies. Yet, no general expression for the stress tensor exists for the VM, missing a microscopic link to VM forces. In this seminar, I will first present a microscopic derivation of the VM stress tensor, directly linking mesoscopic stresses to the microscopic forces of the model. The resulting stress field naturally contains a freedom in how edge tensions are distributed among neighboring cells, recovering previous formulations as particular realizations and suggesting possible connections with cytoskeletal force-transmission architectures in real tissues. I will then discuss the problem of parametric degeneracy in the Vertex Model and how it affects measurable quantities such as the shape index and the stress tensor, and present some force-inference results applied to the Enveloping Layer (EVL) during annual killifish epiboly, revealing correlations between the mechanical properties of individual cells and the geometric heterogeneity of the tissue.