Functionalized Lipid Nanoparticles for Targeted RNA Delivery in Immune and Inflammatory Diseases

Lipid nanoparticles (LNPs) have become an important platform for the delivery of RNA therapeutics, including messenger RNA (mRNA) and small interfering RNA (siRNA). However, most clinically approved LNP formulations exhibit strong liver tropism following systemic administration, which limits efficient delivery to extrahepatic tissues. This inherent biodistribution profile has therefore been recognized as a key challenge for expanding the therapeutic applications of RNA nanomedicine. Recent efforts have focused on engineering functionalized LNP systems to improve delivery specificity beyond the liver. Surface modification with targeting ligands-such as antibodies, peptides, and nucleic acid aptamers-can promote receptor-mediated uptake by specific immune cell populations, including macrophages, dendritic cells and T lymphocytes. In parallel, advances in lipid design have improved intracellular RNA delivery by facilitating endosomal escape. These developments have broadened the potential use of RNA nanomedicine for inflammatory disorders, including autoimmune diseases, neuroinflammation, and cardiovascular inflammation. Functionalized LNPs are also being investigated for in vivo engineering of immune cells. This review summarizes current strategies for designing functionalized LNP systems, highlights their emerging applications in immune and inflammatory diseases, and discusses key challenges for clinical translation.