Cationic lipids via multi-component Passerini reaction for non-viral gene delivery

Lipid nanoparticles (LNPs) are the most advanced non-viral platform for nucleic acid delivery, holding enormous potential applications in clinical therapy. However, some shortcomings remain, such as complex synthetic routes, low synthetic yield, and high cost. In this study, a series of lipid molecules with different cationic headgroups and hydrophobic tails were designed and prepared via Passerini reaction, which provided a convenient multi-component one-step synthetic process toward the lipid molecules with variable product structures for structure-activity relationship studies. The LNPs formed from these lipids could compress DNA efficiently and form stable lipoplexes with low cytotoxicity. The gene transfection efficiency was largely affected by the lipid structure including the cationic headgroup and hydrophobic tails. The lipids A3 with equal C14 length tails could induce the highest transfection efficiency, which was up to 25 times higher than Lipo 2000. Compared to the commercial transfection reagent, the efficiency of target LNPs was less negatively affected by serum. Mechanism studies by confocal microscopy and flow cytometry revealed that lipids with equal C14 length tails led to more efficient cellular uptake, which might contribute to their higher transfection efficiency. This study provides a new strategy for the construction of cationic lipid gene vectors for non-viral gene delivery by multi-component Passerini reaction.