F10T5 is a furan-derived ionizable lipid developed for mRNA delivery to the central nervous system through the meningeal lymphatic pathway. Its architecture incorporates an ionizable polyamine region and four hydrophobic tails containing acid-sensitive acetal linkages. Following subcutaneous administration near the deep cervical lymph nodes, F10T5 LNPs enabled functional mRNA expression in neurons, microglia, and astrocytes while producing relatively low signals in peripheral organs. Cre mRNA delivery resulted in tdTomato expression in approximately 8.93% of neurons, 7.0% of microglia, and 9.9% of astrocytes in mice. Compared with the co-lead lipid F11T6, F10T5 showed comparable total brain luciferase expression, stronger astrocyte transfection, and lower peripheral-organ distribution. Its activity was associated primarily with improved endosomal escape rather than increased cellular uptake. F10T5 remains a preclinical research lipid, and its repeat-dose safety, pharmacokinetics, and performance in larger animals require further evaluation.
