Preparation of arginine modified PEI-conjugated chitosan copolymer for DNA delivery

Polyethylenimine-conjugated chitosan (CS-PEI) and arginine modified polyethylenimine-conjugated chitosan (CS-PEI-Arg) were prepared, and the copolymers were characterized by FTIR, 1H NMR, and XRD. The properties of these copolymers like plasmid DNA (pDNA) binding capacity, complexes' size and zeta potential, cytotoxicity and transfection efficiency were also evaluated. The results show that CS-PEI-Arg derivatives can bind pDNA thoroughly, and form complexes with sizes about 170 nm. Cytotoxicity assay in HepG2 and 293 T cells show that CS-PEI-Arg has lower cytotoxicity compared with CS-PEI, which is similar to CS and far below that of PEI. In vitro luciferase assay show that CS-PEI-Arg has better transfection efficiency than CS-PEI, which is superior to that of PEI. The best transfection efficiency of CS-PEI-Arg (N/P = 50) is 2.3-fold, 4.2-fold of those of CS-PEI (N/P = 20) and PEI's (N/P = 10) efficiency respectively. These results display that CS-PEI-Arg is a promising candidate as an efficient gene vector.