Nebulization-stable lipid-polymer hybrid nanoparticles for mRNA delivery in advanced in vitro respiratory models

Pulmonary delivery of messenger RNA (mRNA) offers a promising strategy for local vaccination and treating respiratory diseases, but aerosolization stress and airway barriers remain major obstacles. Here, we developed PEG-free lipid-polymer hybrid nanoparticles (mucLPs) composed of a solid polylactic acid (PLA) core and an engineered lipid corona. Nine formulations were screened by varying lipid composition and were evaluated for physicochemical properties, mRNA association, cytocompatibility, stability during vibrating-mesh nebulization, and transfection. The lead formulation, mucLP3, combined high mRNA association with a negative post-loading surface charge and preserved its size distribution and reporter activity after nebulization. By contrast, the SM-102-based reference LNP tested under the same conditions showed aggregation and reduced reporter expression after nebulization. Non-nebulized mucLP3 also supported mRNA expression in airway epithelial cell lines, mouse lung organoids, and primary human airway epithelial cultures maintained at an air-liquid interface. These data establish a proof of concept for a PEG-free lipid-polymer hybrid architecture that tolerates the tested nebulization procedure and remains functional in respiratory models of increasing complexity. Direct mucus-transport measurements, aerosol-deposition studies, and in vivo efficacy studies will be required to establish pulmonary delivery performance.