Jennifer Young, University of North Carolina, Chapel Hill


A volume conserving, fluid-structure Interaction model of cellular blebbing


Abstract: Animal cells are composed of organelles, cytoplasm, a cytoskeleton and an encasing plasma membrane. A "bleb" is a balloon-like protrusion of the plasma membrane that forms when the membrane separates from the underlying cytoskeletal network of actin filaments, and is pushed outward by flowing cytoplasm. Blebs are one of a number of cell motility mechanisms and they also play a key role in apoptosis and mitosis. The physics behind bleb formation is not yet clearly understood. We propose a mathematical model based on the following assumptions: Once the membrane and cytoskeleton have separated, the creation of blebs is driven by pressure gradients in the flowing cytoplasm. This two-dimensional model includes the motion of the actin filaments, the plasma membrane, the cytoplasm, and their interactions. The filaments and membrane are modeled by elasticity equations while the cytoplasm is modeled by the Stokes equation. A volume constraint is also included in the model to maintain the overall cell volume at a constant value. These components of the model interact with one another through external forces and boundary conditions. I present here some results of the computational simulations of cellular blebbing.

Advisor: Sorin Mitra (University of North Carolina, Chapel Hill)