RHEOLOGY AND FLOW OF MUCUS IN HUMAN BRONCHIAL EPITHELIAL CELL CULTURES

The propulsion of mucus in human airways toward the trachea by the collective and coordinated action of cilia, known as mucociliary clearance, remains an outstanding modeling and computational challenge. A model system for mucociliary clearance is provided by human bronchial epithelial (HBE) cell cultures that generate macroscopic mean rotational flow. We coarse grain the coordinated cilia propulsion into an imposed dynamic velocity condition on the flat base of a cylinder. A multi-mode Giseskus nonlinear viscoelastic constitutive model derived from rheological data of mucus is employed for the mucus layer. The full system of governing equations for the transient and stationary axisymmetric flow field and air-mucus interface is solved numerically. Our modeling is the first step toward a platform for several purposes: to test accuracy of the constitutive modeling of mucus; to build a faithful model of the cilia-mucus boundary condition; to simulate both the flow and stress fields throughout the mucus layer; to explore the linear and nonlinear viscoelastic behavior of the mucus flow; and to explore the advection-diffusion process of a drug concentration dropped at the surface of the cell culture, and illustrate how the absorption by the bottom plate varies versus the initial drop position and the diffusion coefficient.Doctor of Philosoph