Yanhao Zhang, Bing Shao, Kai Jiang, Jie Cen, Yang Liu, Jiajia Tan, Lin Zhang, Keyu Li, Chunyu You, Zhihua He, Guoying Zhang, Minglong Chen, Jinming Hu, Shiyong Liu
Efficient and selective mRNA delivery to immune-related organs, particularly the spleen, remains a major barrier to the broader clinical translation of mRNA therapeutics. Here, leveraging the clinically approved SM-102/ALC-0315 ionizable lipid scaffold, we rationally designed a combinatorial library of fluorinated ionizable lipids (FILs) by systematically modulating hydrophobic tails and fluorine stoichiometry. Through synthesis and evaluation of 74 candidate FILs, we identify SSC6F5 lipid nanoparticles (LNPs) as a lead formulation with exceptional spleen-targeting specificity (>90%) across intravenous, intramuscular, and subcutaneous administrations. Compared to clinically approved SM102 LNPs and spleen-tropic SM102/18PA (SORT) LNPs, intravenously administered SSC6F5 LNPs achieve 10.6-fold and 63.1-fold higher splenic mRNA transfection, respectively. Proteomic analysis of protein corona on SSC6F5 LNPs reveals significant enrichment of apolipoprotein D (Apod) and reduction in apolipoprotein H (Apoh), implicating a novel endogenous recognition pathway driving enhanced spleen targeting. Functionally, SSC6F5 LNPs enable efficient genome editing in splenic macrophages, dendritic cells, T cells, and B cells in Ai9 mice, and elicit potent CD8 + T cell and humoral responses in a B16-OVA murine melanoma model, resulting in significant tumor growth inhibition. These findings establish fluorinated lipids as a mechanistically distinct and translationally versatile platform for precision spleen-targeted mRNA delivery in gene editing and cancer immunotherapy.