A3T2C7 (CP-LC-1495) is a biodegradable ionizable lipid featuring three β-propionate linkers and an azetidine polar head, formulated in four-component LNPs. It demonstrates exceptional lung-targeted mRNA delivery with 97.1% selectivity and high protein expression (1.21×10⁸ p/s) in mice. Its slightly positive zeta potential (~3.5 mV) correlates with lung tropism, likely mediated by protein corona enrichment of vitronectin and prothrombin. The β-propionate structure enables pH-sensitive biodegradability for enhanced endosomal escape while maintaining low cytotoxicity (>90% cell viability). This lipid enables organ-specific mRNA delivery without permanently charged additives, outperforming conventional SORT strategies in selectivity and expression efficiency.
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