University of Pennsylvania researchers reported redesigned lipid nanoparticles that shift mRNA delivery away from the liver and toward lymph nodes in vivo. The work, published in the Journal of the American Chemical Society, describes “aroLNPs” built by re-engineering ionizable lipids to confer lymph node tropism. In mouse models, the best-performing aroLNP formulations delivered roughly 10-fold less mRNA to the liver than a Moderna ionizable lipid reference while maintaining robust accumulation in lymph nodes. The study frames lymph nodes as the primary immunological training site for vaccine antigen presentation. The reported chemistry includes aromatic, ionizable lipid scaffolds tuned through regiochemistry and disulfide bonds intended to support biodegradability. The findings focus on structural lipid parameters that affect biodistribution and may inform next-generation mRNA vaccine formulations aimed at improving potency and tolerability through better tissue targeting.