Wet-adhesive γ-PGA/ε-PLL hydrogel loaded with EGF for tracheal epithelial injury repair.

Following the global COVID-19 pandemic, the incidence of tracheal epithelial injury is increasing. However, the repair of tracheal epithelial injury remains a challenge due to the slow renewal rate of tracheal epithelial cells (TECs). In traditional nebulized inhalation treatments, drugs are enriched in the lungs or absorbed into the blood, reducing drug concentration at the tracheal injury site. In this study, we prepared an epidermal growth factor (EGF)-loaded gamma-polyglutamic acid (γ-PGA)/epsilon-poly-L-lysine (ε-PLL) (PP) hydrogel (EGF@PP) to promote the repair of tracheal epithelial injury. Epidermal growth factor promotes the proliferation of TECs and enhances vascularization, thereby accelerating injury repair. The PP hydrogel exhibits outstanding wet adhesion, slow drug release, and antibacterial and anti-inflammatory properties, making it suitable for application in the airways and creating an environment conducive to epithelial repair. Here, we established a rabbit model of tracheal injury using a laser to destroy the tracheal epithelium and delivered EGF@PP powder to the injury site under fiberoptic bronchoscopy guidance. Our findings revealed that this was an effective therapeutic strategy for accelerating the repair of tracheal epithelial injury.