A tumor-targeting near-infrared laser-triggered drug delivery system based on GO@Ag nanoparticles for chemo-photothermal therapy and X-ray imaging

In this study, a GO@Ag nanocomposite was synthesized by chemical deposition of Ag nanoparticles onto graphene oxide (GO) through a hydro thermal reaction, and doxorubicin (DOX), one of the most effective drugs against a wide range of cancers, was employed as the model drug and linked to GO@Ag via ester bonds with a very high drug loading efficiency (similar to 82.0%, weight ratio of DOX/GO@Ag), then GO@Ag-DOX was functionalized by DSPE-PEG2000-NGR, giving GO@Ag-DOX with active tumor-targeting capacity and excellent stability in physiological solutions. The release profiles of DOX from GO@Ag-DOX-NGR showed strong dependences on near-infrared (NIR) laser and the SPR effect of Ag nanoparticles. Compared with free DOX in an in vivo murine tumor model, GO@Ag-DOX-NGR afforded much higher antitumor efficacy without obvious toxic effects to normal organs owing to 8.4-fold higher DOX uptake of tumor and 1.7-fold higher DOX released in tumor with NIR laser than the other tissues. Besides, in this work, GO@Ag-DOX-NGR not only served as a powerful tumor diagnostic X-ray contrast agent, but also as a strong agent for photothermal ablation of tumor, the ability of GO@Ag-DOX-NGR nanoparticles to combine the local specific chemotherapy with external photothermal therapy (PIT) significantly improved the therapeutic efficacy. GO@Ag-DOX-NGR showed excellent chem-photothermal therapeutic efficacy, tumor-targeting property, NIR laser-controlled drug releasing function and X-ray imaging ability, demonstrating that there is a great potential of GO@Ag-DOX-NGR for cancer diagnosis and therapy. (C) 2014 Elsevier Ltd. All rights reserved.