A new strategy for the extrahepatic delivery of lipid-based nanomedicines: a protein corona-mediated selective targeting system based on an ionizable cationic lipid library

Applying lipid nanoparticle (LNP) technology to ribonucleic acid (RNA) nanomedicines was integral to the success of mRNA vaccines against COVID-19. To expand the power of LNP technology, extrahepatic delivery systems have been developed using specific ligands that target the cells in question. However, recent increases in evidence support targeting without the need to attach specific ligands to nanocarriers. In this review, we focused on protein corona-mediated extrahepatic delivery of nanoparticles as an alternative to classic ligand-mediated active targeting. First, the interaction of LNPs with biological components and the impact that the physicochemical properties of LNPs exert on their biological fate are discussed. Then, we highlight a new system that targets activated hepatic stellate cells (aHSCs) as a successful model achieved through intensive optimization of LNPs based on an ionizable cationic lipid library. We also discuss cumulative evidence that support the ligand-free extrahepatic delivery of nanoparticles to a broad diversity of tissues, such as the spleen, lungs, brain, tumors, kidneys, placenta, pancreas, and bone marrow. In conclusion, we propose protein corona-mediated extrahepatic delivery as a new strategy of active targeting for RNA nanomedicines and inspire the future directions in this area.