A microfluidic device to apply shear stresses to polarizing ciliated airway epithelium using air flow

Organization of airway epithelium determines ciliary beat direction and coordination for proper mucociliary clearance. Fluidic shear stresses have the potential to influence ciliary organization. Here, an in vitro fluidic flow system was developed for inducing long-term airflow shear stresses on airway epithelium with a view to influencing epithelial organization. Our system consists of a fluidic device for cell culture, integrated into a humidified airflow circuit. The fluidic device has a modular design and is made from a combination of polystyrene and adhesive components incorporated into a 6-well filter membrane insert. We demonstrate the system operates within physiologically relevant shear and pressure ranges and estimate the shear stress exerted on the epithelial cell layer as a result of air flow using a computational model. For both the bronchial epithelial cell line BEAS2B and primary human tracheal airway epithelial cells, we demonstrate that cells remain viable within the device when exposed to airflow for 24 h and that normal differentiation and cilia formation occurs. Furthermore, we demonstrate the utility of our device for exploring the impact of exposing cells to airflow: our tool enables quantification of cytoskeletal organization, and is compatible with in situ bead assays to assess the orientation of cilia beating.