Membrane-destabilizing ionizable phospholipids for organ-selective mRNA delivery and CRISPR–Cas gene editing

Endosomal escape remains a fundamental barrier hindering the advancement of nucleic acid therapeutics. Taking inspiration from natural phospholipids that comprise biological membranes, we report the combinatorial synthesis of multi-tailed ionizable phospholipids (iPhos) capable of delivering messenger RNA or mRNA/single-guide RNA for gene editing in vivo. Optimized iPhos lipids are composed of one pH-switchable zwitterion and three hydrophobic tails, which adopt a cone shape in endosomal acidic environments to facilitate membrane hexagonal transformation and subsequent cargo release from endosomes. Structure–activity relationships reveal that iPhos chemical structure can control in vivo efficacy and organ selectivity. iPhos lipids synergistically function with various helper lipids to formulate multi-component lipid nanoparticles (called iPLNPs) for selective organ targeting. Zwitterionic, ionizable cationic and permanently cationic helper lipids enable tissue-selective mRNA delivery and CRISPR–Cas9 gene editing in spleen, liver and lungs (respectively) following intravenous administration. This rational design of functional phospholipids demonstrates substantial value for gene editing research and therapeutic applications.