Polyethylenimine-functionalized graphene oxide as an efficient gene delivery vector

A novel gene delivery system based on graphene oxide chemically-functionalized with branched polyethylenimine (PEI-GO) is reported. The PEI-GO conjugate was formed by the covalent linking of PEI and GO via an amide bond by widely used EDC chemistry. Thus-prepared PEI-GO exhibits an excellent ability to condense DNA at a low mass ratio with a positive potential of 49 mV. A WST assay reveals that PEI-GO is significantly less cytotoxic than PEI 25 kDa. Finally, the transfection efficiency of PEI-GO was evaluated. It is demonstrated that the luciferase expression of PEI-GO is comparable or even higher than that of the PEI 25 kDa at optimal mass ratio. Moreover, intracellular tracking of Cy3-labelled pGL-3 indicates that PEI-GO could effectively deliver plasmid DNA into cells and be localized in the nucleus. These findings suggest that PEI-GO is a promising candidate for efficient gene delivery.