Graphene/cobalt nanocarrier for hyperthermia therapy and MRI diagnosis

Graphene/cobalt nanocomposites are promising materials for theranostic nanomedicine applications, which are defined as the ability to diagnose, provide targeted therapy and monitor the response to the therapy. In this study, the composites were synthesized via chemical method, using graphene oxide as the source material and assembling cobalt nanoparticles of 15nm over the surface of graphene sheets. Various characterization techniques were then employed to reveal the morphology, size and structure of the nanocomposites, such as X-ray diffraction analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, high resolution transmission electron microscopy and ultraviolet visible spectroscopy. Using ion-coupled plasma optical emission spectroscopy, cobalt concentration in the nanocomposites was found to be 80%. In addition, cytotoxicity of graphene/cobalt nanocomposites were evaluated using 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide or MTT assay. MTT viability assay exhibited biocompatibility to L929 mouse fibroblasts cells, under a high dose of 100μg/mL over 24h. Hyperthermia results showed the superior conversion of electromagnetic energy into heat at 350kHz frequency for 0.01 and 0.005g/L of the nanocomposites solution. The measured heat generation and energy transfer results were anticipated by the finite element analysis, conducted for the 3D structure. Magnetic resonance imaging characteristics also showed that negatively charge graphene/cobalt nanocomposites are suitable for T1-weighted imaging.