Multi-functionalized graphene oxide complex as a plasmid delivery system for targeting hepatocellular carcinoma therapy

A novel efficient graphene-based gene delivery vector was synthesized by continuous covalent functionalization of graphene oxide (GO) with polyethylenimine (PEI), polyethylene glycol (PEG) and folic acid (FA), followed by loading si-Stat3 via electrostatic adsorption (GO-PEI-PEG-FA/si-Stat3). We investigated the effect of changing the content of PEI in the complex on the effective diameter and transfection efficiency. It was found that as the PEI content in the complex increased, the effective diameter was reduced until a point where it remained almost unchanged and the transfection efficiency of complex became higher. The results also showed that the transfection efficiency is relatively high with the content of PEI in the complex at 61 wt% without any obvious cytotoxicity. At the same time, the stability of the complex in physiological conditions was improved. The GO-PEI-PEG-FA/si-Stat3 complex exhibited an excellent ability to silence Stat3 expression for targeting tumor hepatocellular carcinoma in vitro.