▎ 摘　　要

In this work, we developed a T-2-weighted contrast agent based on graphene oxide (GO)/Fe3O4 hybrids for efficient cellular magnetic resonance imaging (MRI). The GO/Fe3O4 hybrids were obtained by combining with co precipitation method and pyrolysis method. The structural, surface and magnetic characteristics of the hybrids were systematically characterized by transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), AFM, Raman, FT-IR and XRD. The GO/Fe3O4 hybrids were functionalized by modifying with anionic and cationic polyelectrolyte through layer-by-layer assembling. The fluorescence probe fluorescein isothiocyanate (FITC) was further loaded on the surface of functionalized GO/Fe3O4 hybrids to trace the location of GO/Fe3O4 hybrids in cells. Functionalized GO/Fe3O4 hybrids possess good hydrophilicity, less cytotoxicity, high MRI enhancement with the relaxivity (r(2)) of 493 mM(-1) s(-1) as well as cellular MRI contrast effect. These obtained results indicated that the functionalized GO/Fe3O4 hybrids could have great potential to be utilized as cellular MRI contrast agents for tumor early diagnosis and monitoring. (C) 2017 Elsevier B.V. All rights reserved.