ABSTRACT:  This seminar focuses on practical applications and innovative numerical methods for modeling the heterogeneous mucus biofilm in human lungs, with the goal of monitoring cystic fibrosis (CF) therapies. From an operational perspective, our objective is to predict whether a given therapy significantly influences mucociliary clearance (specifically, the functionality of respiratory mucus in efficiently moving toward the oesophagus). In contrast, dysfunctional mucus fails to move adequately, preventing the clearance of allergens, toxic agents, viruses, bacteria, and their residual by-products (such as DNA filaments and altered mucoid components) from the lung surface. Here the system under study consists of mucus composed of a Newtonian periciliary liquid (PCL) and highly concentrated mucins secreted by goblet cells, flowing through and above the ciliated epithelial cells. This environment is modeled at the pore scale, resolving individual cilia. The cilia’s vibrations induce mixing between the mucins and PCL, triggering a reaction that produces a polymerized mucus with spatially and temporally variable rheological properties. The main objective of numerical simulation in such configurations is to predict whether a mucus is functional or not, with respect to the rheological features that are measured from mucus samples. The full model involves quasi-stationary Darcy-Brinkman-Stokes with space and time variable power-law and Carreau law, strongly coupled to diffusion and transport of mucins. The numerical method used in the present work is a dedicated hybrid grid-particle method particularly useful to describe such a complex transport phenomena.

BIOSKETCH:  Philippe Poncet obtained his PhD from Grenoble Alpes University (France) in 2001, specializing in vortex methods for 3D flow simulation and control. He joined the Toulouse Institute of Mathematics as an Assistant Professor and later became Associate Professor (2007). In 2013, he joined the University of Pau & Pays de l’Adour (UPPA) as a Full Professor and is now the Director of the CNRS Research Unit “Laboratory of Mathematics and their Applications”. Among several research projects on reactive microfluidics, two focus on modeling human lung epithelium cells and studying mucociliary clearance in cystic fibrosis with clinical assessment.