Charge-assisted stabilization of lipid nanoparticles enables inhaled mRNA delivery for mucosal vaccination

Inhaled delivery of messenger RNA (mRNA) using lipid nanoparticle (LNP) holds immense promise for treating pulmonary diseases or serving as a mucosal vaccine. However, the unsatisfactory delivery efficacy caused by the disintegration and aggregation of LNP during nebulization represents a major obstacle. To address this, we developed a charge-assisted stabilization (CAS) strategy aimed at inducing electrostatic repulsions among LNPs to enhance their colloidal stability. By optimizing the surface charges using a peptide-lipid conjugate, the leading CAS-LNP demonstrated exceptional stability during nebulization, resulting in efficient pulmonary mRNA delivery in mouse, dog, and pig. Inhaled CAS-LNP primarily transfect dendritic cells, triggering robust mucosal and systemic immune responses. We demonstrated the efficacy of inhaled CAS-LNP as a vaccine for SARS-CoV-2 Omicron variant and as a cancer vaccine to inhibit lung metastasis. Our findings illustrate the design principles of nebulized LNPs, paving the way of developing inhaled mRNA vaccines and therapeutics.