Improving dispersive property, biocompatibility and targeting gene transfection of graphene oxide by covalent attachment of polyamidoamine dendrimer and glycyrrhetinic acid.

The surface functional groups of GO have significant effects on the performances of GO-based gene delivery vector. In this work, the polyamidoamine (PAMAM) dendrimer and glycyrrhetinic acid (GA) were tethered onto the GO surface by one-step covalently cross-linking method. The micro-morphology, surface functional groups, and zeta potential of the obtained GO-PAMAM-GA hybrid were characterized and verified. The effects of GA amount in the hybrid on the dispersive property in cell culture medium, in vitro cytotoxicity to human hepatocarcinoma (SMMC-7721) and human embryonic kidney (HEK-293) cells, and gene (plasmid DNA of enhanced green fluorescent protein) transfection capacity were investigated in detail. Under optimal conditions, the obtained hybrid shows small average size (about 160 nm) and has very good dispersive stability (in 30 days) in cellular culture medium. Compared with the GO-PAMAM without GA modification, the GO-PAMAM-GA hybrid exhibits greatly enhanced biocompatibility to the two cell lines. The cellular viability of SMMC-7721 cells still retains about 98% even the concentration of the hybrid up to 200 μg mL. The gene transfection capacity of the GO-PAMAM has been improved about 50% through the GA functionalization. Moreover, the GO-PAMAM-GA hybrid possesses targeting gene transfection to SMMC-7721 cells.