Functionalized graphene nanosheets with improved dispersion stability and superior paclitaxel loading capacity

This study reports our attempt of improving dispersibility of reduced graphene oxide (rGO) through differential functionalization of carboxyl moieties with ethylene diamine (EDA) and folic acid (FA) using carbodimide chemistry. Successful covalent linkage was demonstrated through FT-IR, Raman and energy dispersive X-ray spectroscopy. Functionalized nanosheets (GNs) produced a stable dispersion up to 0.1 wt% which remained unaffected against salt- and protein-induced aggregation. Hemolysis test showed negligible toxicity of GNs in murine erythrocytes up to 100 μg/ml. Non-covalent hydrophobic and п-п stacking interactions between GNs and paclitaxel (PLX) offered a superior loading (95.07%) capacity. The latter could substantially minimize the incidence of disruptive protein-carrier interactions and thus, inflate the biomedical potential of graphene materials. Besides, the attached FA groups can be exploited for target-selective delivery of PLX to folate receptor over-expressing tumor cells.