Introduction of graphene oxideGrapheneFullereneCarbon NanotubeGraphiteH2SO4, KMnO4A:Peroxide bridge bondB: HydroxyC:CarboxylGraphene Oxide (GO)Concentrated H2SO4Addition ofgrapheneStirred for 10 minAddition ofKMnO4Stirred for 30 min at 80℃Addition ofH2OStirred for 6 h at 35℃Addition ofH2O and H2O2Stirred for 10 min at rt.washed withH2Ofreeze-driedafter sonicationGrapheneFullereneCarbon NanotubeGraphiteH2SO4, KMnO4A:Peroxide bridge bondB: HydroxyC:CarboxylGraphene Oxide (GO)Introduction of graphene oxideProperties of GO? Good water dispersibility? No cytotoxicity? Facile surface modification? Low manufacturing cost?Effective electron transfer