A neutral envelope-type nanoparticle containing pH-responsive and SS-cleavable lipid-like material as a carrier for plasmid DNA.

SS-cleavable proton-activated lipid-like material (ssPalm) functions as a key element in a lipid nanoparticle in which pDNA is encapsulated. The ssPalm contains dual sensing motifs that can respond to the intracellular environment; a proton-sponge unit (tertiary amines) that functions in response to an acidic environment (endosome/lysosome), and disulfide bonding that can be cleaved in a reducing environment (cytosol).