Engineering a Multilayer Microfluidic Airway-On-A-Chip with Tunable GelMA Hydrogel for Physiologically Relevant Aerosol Exposure Studies

Climate change-driven increases in forest fires pose a major global health risk due to exposure to smoke containing hazardous gases and fine particulates, emphasizing the need for physiologically relevant in vitro airway models for studying smoke-induced responses. Microfluidic lung-on-a-chip technologies provide a strong foundation for in vitro airway modeling and ongoing developments are expanding their ability to incorporate multicellular organization, extracellular matrix complexity, and physiologically relevant exposure methods. This work presents the optimization and integration of a photopolymerizable gelatin methacrylate (GelMA)-based hydrogel into a microfluidic airway-on-a-chip that models the human small conducting airways and supports controlled aerosol exposure to wood smoke. The GelMA hydrogel was optimized to support fibroblast encapsulation, endothelial, and epithelial adhesion and robust mechanical stability. The device combines the hydrogel with a compartmentalized microchannel layout, and sacrificial molding to create a 3D organotypic airway culture featuring a multilayer architecture, 3D stromal matrix, and a perfusable vasculature-like lumen. Coupling the platform with a custom aerosol exposure system enables precise, biomimetic exposure to whole wood smoke. Proof-of-concept studies using transforming growth factor beta1 (TGF-{beta}1) and whole wood smoke elicited expected inflammatory and fibrotic responses, validating the platforms physiological relevance for inhalation studies and investigating smoke-induced airway remodeling and inflammation.