Graphene oxide-fullerene C60 (GO-C60) hybrid for photodynamic and photothermal therapy triggered by near-infrared light

Photodynamic therapy (PDT) and photothermal therapy (PTT) are two promising methodologies for cancer therapy. Although a variety of materials which can be used in PDT and PIT have been developed in the past decades, those showing the combined effect of PDT and PTT under NIR irradiation are rare. Graphene oxide (GO) and fullerene C-60 (denoted as C-60 hereafter) with unique physical and chemical properties are promising candidates for PTT and PDT, respectively. Here, by using a stepwise conjugation method, a new GO-C-60 hybrid which contains hydrophilic methoxypolyethylene glycol (mPEG) and mono-substituted Co was constructed for combined PDT and PTT. The hybrid shows good solubility in different environments including physiological solutions. The introduction of C-60 to GO did not decrease the photothermal properties of GO, while the conjugation of GO to C-60 activated the ability of C-60 to generate singlet oxygen (O-1(2)) in near infrared (NIR) region in aqueous solution. The GO-C60 hybrid also shows good ability to induce the generation of reactive oxygen species (ROS) in Hela cells. Due to the synergistic effect between GO and C-60, GO-C-60 hybrid exhibits superior performance in the inhibition of cancer cells compared to both individuals, indicating its high potential in practical applications. (C) 2016 Elsevier B.V. All rights reserved.