Electrostatically‐Stabilized PEG‐Free Lipid Nanoparticles for Systemic Nucleic Acid Delivery
Lipid nanoparticles (LNPs) have enabled the clinical translation of various nucleic acid cargos, including messenger RNA. Traditional LNP formulations contain a small proportion of lipids conjugated to poly(ethylene glycol), or PEG, which provides advantages of size control, stability, and extended circulation. However, PEGylation of both LNPs and other nano‐carriers raises challenges to efficient gene delivery, including endogenous production of anti‐PEG antibodies, accelerated clearance of multiple doses of LNPs, and reduced cellular uptake and endosomal escape. Here, we design and characterize a fully PEG‐free LNP platform, stabilized alternatively through the electrostatic adsorption of charged polymeric coatings that leverage principles of layer‐by‐layer self‐assembly. A library of carboxylated polyanions confers stability to non‐PEGylated (nonPEG) LNPs under biological stresses. nonPEG layered LNPs (LLNPs) significantly improve transfection of cancer and immune cells in vitro and generate favorable transfection in vivo via multiple routes of administration. In particular, nonPEG LLNPs reduce hepatic transfection by an order of magnitude, a major challenge for targeted LNP gene delivery, while maintaining similar circulation and transfection in other organs. Ultimately, this platform offers a highly modular, tunable approach to incorporate various bioactive moieties to achieve PEG‐free extrahepatic gene delivery.