Biodegradable Nanofiber Membranes for Air–Liquid Interface Culture: Advancing Airway <i>In Vitro</i> Models

Chronic airway diseases represent a significant global health challenge, and reliable <i>in vitro</i> model systems are essential for elucidating the molecular mechanisms underlying these conditions. Although air-liquid interface (ALI) culture systems are among the most effective models for studying airway epithelial cells under physiological conditions, the nonbiodegradable membranes commonly used in current systems present certain limitations. In the present study, biodegradable poly-(l-lactic acid) (PLLA) and poly-(ε-caprolactone) (PCL) nanofiber membranes were fabricated using the electrospinning technique, and novel transwell membrane systems were developed. Optimization studies revealed that the nanofiber diameters ranged between 50 and 275 nm, forming a structure closely resembling the native lung extracellular matrix. Degradation analyses indicated that PLLA and PCL membranes remained structurally stable for up to six months, making them suitable for long-term <i>in vitro</i> airway modeling applications. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy confirmed the chemical stability of the membranes. Additionally, cell culture assays demonstrated high cell viability and strong cellular adhesion. Immunocytochemical analysis revealed β-tubulin expression in bronchial epithelial cells differentiated on the membranes, indicating successful epithelial maturation. These findings suggest that biodegradable membranes provide a promising platform for <i>in vitro</i> airway modeling. Furthermore, the use of biodegradable membranes is expected to address a critical need by accurately mimicking the tracheal and bronchial architecture as submucosal tissue analogues, thereby advancing the development of preclinical airway tissue graft constructs.