Speaker
Description
The phase of tissue and its transitions are critical phenomena during development. The Active Vertex Model is a well-known approach for studying tissue mechanical properties. In this model, the tissue is represented as a collection of polygonal cells, with forces applied to the vertices, leading to cell dynamics and rearrangement. This model includes passive forces representing the competition between cellular adhesion and contractility, as well as active forces, which are introduced as cells motility in random directions. In this study, we used the active vertex model to simulate cell dynamics and tissue rearrangement. We obtained the phase diagram of the tissue based on the mean square displacement of cells across a wide range of active and passive forces. The phase diagram shows that increasing the adhesion force in the passive term and increasing active forces or cell motility leads the tissue into a fluid phase. Next, we investigated the geometric properties of the tissue, such as the cell shape index, number of cell vertices (polygonal class), average cell area, and more. The results show that in the fluid state, cells are elongated with a higher number of vertices, while in the solid state, they are more compact, suggesting that tissue state can be determined through geometric properties.In the next step, we considered a group of cells with varying geometric properties, specifically compact cells with higher contractility. Our simulation results showed that this group can form an elongated pattern, which may be related to processes like cell sorting or branching. This suggests that mechanical forces alone can lead to pattern formation during development
