In this study, we investigated the possible use of novel lipidated sorbitol-based transporters as functional devices for the improvement of non-viral gene delivery. These transporters are composed of a sorbitol scaffold bearing 8 guanidine moieties that mimic the arginine residues of well-known cell-penetrating peptides. In addition, the transporters carry different lipid groups to aid DNA condensation and facilitate lipid vesicle-binding. We found that the transporters described in this study have the potential to function as plasmid DNA/siRNA-condensers and surface ligands for the enhancement of cellular uptake of lipid vesicles. Shorter lipid chains were found to be better for condensation, whereas longer chains were superior surface ligands. The differential activity of different cores might be explained by facilitated decondensation of cores prepared with transporters comprised of shorter lipid chains. However, we suggest that there is an optimum value of decondensation to achieve higher transfection activities. The proper use of the transporters presented in this study enabled us to prepare a highly efficient non-viral gene delivery system based on a core–shell structure, in which a condensed DNA core is encapsulated by a lipid envelope. A multifunctional envelope-type nano-device prepared with an optimal surface ligand favorably competes with commonly used transfection systems.Graphical abstract
Structures of lipidated transporters used in the present study. Compounds 1a to 1c differ in the number of carbon atoms (n) in the acyl chains. Compound 2 differs from 1c in the structure of the R group (Cbz = carbobenzyloxy). Compound 3 differs from 1c in the linker chain type.