Graphene oxide based theranostic platform for T1-weighted magnetic resonance imaging and drug delivery

Magnetic resonance imaging (MRI) is a powerful and widely used clinical technique in cancer diagnosis. MRI contrast agents (CAs) are often used to improve the quality of MRI-based diagnosis. In this work, we developed a positive T1 MRI CA based on graphene oxide (GO)-gadolinium (Gd) complexes. In our strategy, diethylenetriaminepentaacetic acid (DTPA) is chemically conjugated to GO, followed by Gd(III) complexation, to form a T1 MRI CA (GO-DTPA-Gd). We have demonstrated that the GO-DTPA-Gd system significantly improves MRI T1 relaxivity and leads to a better cellular MRI contrast effect than Magnevist, a commercially used CA. Next, an anticancer drug, doxorubicin (DOX), was loaded on the surface of GO sheets via physisorption. Thus-prepared GO-DTPA-Gd/DOX shows significant cytotoxicity to the cancer cells (HepG2). This work provides a novel strategy to build a GO-based theranostic nanoplatform with T1-weighted MRI, fluorescence imaging, and drug delivery functionalities.