Predictive Screening of Ta₄C₃ MXene as an Inhalable Nanotherapeutic Based on an Advanced 3D Air-Liquid Interface Lung...

The rapid development of two-dimensional (2D) MXenes has outpaced our understanding of their pulmonary safety, leaving a critical gap in clinical translation due to inconsistent data from traditional 2D cell cultures. Herein, we developed an immunocompetent three-dimensional (3D) alveolar model comprising A549 epithelial cells, MRC-5 fibroblasts, and THP-1-derived macrophages cultured at the air-liquid interface. This self-organized triculture forms a stratified epithelial-mesenchymal trophic unit with functional surfactant production and cell-cell crosstalk, providing a physiologically relevant platform for the predictive screening of potential nanomedicines. Following thorough characterization, we utilized this system to investigate the therapeutic potential of in-house synthesized Ta₄C₃ MXene nanosheets across three size fractions (100-500 nm, 500-2000 nm, and ≥2000 nm). Key biological events leading to lung inflammation and fibrosis, including reactive oxygen species (ROS) accumulation and the release of pro-inflammatory and pro-fibrotic markers, demonstrated the responsiveness of the model. All of the size fractions showed high biocompatibility. Cryogenic transmission electron microscopy and energy-dispersive X-ray spectroscopy confirmed efficient cellular internalization. Notably, the 100-500 nm fraction induced the most pronounced therapeutic reaction by scavenging ROS and promoting macrophage polarization shift from M1 to M2 and arresting fibrotic remodeling. The addition of macrophages in the tricultures led to heightened inflammatory and fibrotic responses, enabling more sensitive detection of the anti-inflammatory and antifibrotic effects of Ta₄C₃ MXenes. This study establishes a rapid 3D alveolar model for predictive assessment of pulmonary safety and therapeutic efficacy upon Ta₄C₃ treatment.