Provided are modified lipid compounds and their use in the formation of lipid assemblies. Also provided are lipid assemblies including (a) an amphoteric lipid including in covalent association with (i) one or more acyl chains； (ii) one or more weak base moiety； (iii) one or more weak acid moiety； the lipid assembly also including (b) one or more additional lipids, at least one of which being a zwitterionic lipid. In some embodiments, the amphoteric lipid is a compound including (a) a tri-functional moiety； (b) two non-phosphate lipid chains associated with two of the functional moieties of said tri-functional moiety； (c) optionally a spacer moiety associated with the third of the functional moieties of said tri-functional moiety； and (d) a polyalkylamine optionally including a short peptide with one to several carboxylic acid residues. Further provided are the uses of the lipid assembly, inter alia, for transfection or cancer treatment.
