Laser-assisted in situ synthesis of graphene-based magnetic-responsive hybrids for multimodal imaging-guided chemo/photothermal synergistic therapy.

Magnetic graphene-based hybrids are being increasing recognized as an effective nanotheranostic agent in biomedicine. Conventional technologies for their synthesis have drawbacks not only from a synthetic standpoint, mainly requiring high temperatures and multi-step processes, but also from a biological perspective, chemical precursors or surfactants involved in the chemical process are toxic to cells. Herein, we report a novel approach for one-step fabricating magnetic graphene hybrid nanocomposites based on laser irradiation of an Fe target in GO-PEG aqueous solution at room temperature without using any other chemical reagent. TEM, XPS, FT-IR, XRD, Mossbauer spectrum and VSM observation reveal that γ-Fe2O3 nanoparticles were directly grown on the surface of GO-PEG with uniform morphology and superior dispersibility. These GO-PEG-γ-Fe2O3 nanocomposites (labeled as GPF) showed low cytotoxicity in vitro compared to chemically synthesized nanoparticles since the pulsed-laser-ablation-in-liquid (PLAL) process is free of toxic agents. After tail vein injection of the nanotheranostics, the tumor was clearly mapped by T2-weighted magnetic resonance of γ-Fe2O3, photothermal imaging of graphene and fluorescence imaging of loaded antitumor DOX. Meanwhile the tumor cells both in vitro and in vivo achieved highly superior inhibition by the synergistic chemo/photothermal therapeutic effect which provided an intense heating effect and enhanced DOX release upon 808 nm NIR light exposure. The results revealed that the magnetic graphene-based hybrids prepared by PLAL is competent for future multi-modal imaging assisted tumor targeted chemo/photothermal synergistic therapy of cancer.