Inhalable bioadhesive barrier for lung protection and clearance of fine particulate matter.

Fine particulate matter (PM) can bypass nasal filtration and accumulate in the lower respiratory tract, where prolonged deposition may cause chronic inflammation, pulmonary fibrosis, and other respiratory diseases. Although commercial nasal sprays offer protection in the upper airways, they are inadequate for safeguarding the lower respiratory tract and lung. In this study, we introduce an inhalable bioadhesive barrier (IBB) specifically engineered to deposit in the lower airways, where it forms an adhesive hydrogel barrier upon contact with airway mucus and actively scavenges inhaled fine PM. With optimized aerodynamic properties, IBB can efficiently deposit throughout the bronchi and bronchioles, providing protection for up to 8 h. The IBB captures and encapsulates inhaled PM, enabling its clearance from the airways within 48 h, thus preventing long-term retention. Compared to commercial nasal sprays, intranasal inhalation of IBB markedly improved protection against chronic silica exposure in a murine silicosis model. Large animal studies further demonstrated uniform and extensive airway coverage by IBB in porcine models, suggesting strong translational potential for human respiratory protection. This approach provides a safe, efficient, and cost-effective strategy for preventing respiratory diseases induced by chronic exposure to respirable fine particulates.