Lipid nanoparticles (LNPs) have become a key technology for delivering nucleic acids, playing a critical role in the success of mRNA vaccines and RNA-based therapeutics. Established manufacturing methods, including microfluidic mixing and impingement jet mixing, have exhibited excellent scalability, reproducibility, and clinical relevance, most notably during the development of vaccines for SARS-CoV-2. Nevertheless, these techniques are accompanied by challenges related to the handling of organic solvents (ethanol), scalability for personalized medicine, and environmental considerations. This review draws attention to recent innovations in LNP formulation that seek to address these challenges through alternative and complementary approaches. One central focus of this review highlights post-formation encapsulation strategies, utilizing preformed vesicles or other nanostructures. These strategies facilitate modular, on-demand loading of nucleic acids. In addition, organic solvent-free techniques, including thermocycling, calcium-mediated DNA encapsulation, and aqueous sonication, offer new opportunities for biocompatible, streamlined manufacturing. In line with these formulation strategies, the review discusses recent progress in continuous manufacturing platforms, which enable end-to-end process control, real-time analytics, and increased production efficiency. By comparing conventional and emerging techniques, this review provides an overview of the evolving LNP formulation landscape and identifies key opportunities for integrating innovation into conventional production pipelines.
