Biomedical application of sp2 carbon nanomaterials for cancer therapy and molecular imaging

Summary form only given. Biological applications of carbon nanotubes have been attracting tremendous attention recently. In the past few years, we have studied the in vivo biodistribution, tumor targeting, long term fate and toxicity of functionalized single-walled carbon nanotubes (SWNTs) in animals. After intravenous injection into mice, SWNTs are accumulated in reticuloendothelial systems (RES) including liver and spleen, and slowly excreted via biliary pathway in feces without exhibiting obvious side effects . After those fundamental studies, for the first time we have shown that carbon nanotubes can be used as drug delivery vehicles for in vivo cancer treatment in mouse xenograft tumor models to enhance treatment efficacy and/or reduce side effects of chemotherapy drugs. Two commonly used anti-cancer drugs, paclitaxel and doxorubicin have been involved in our studies. In addition, the intrinsic optical properties such as resonance Raman scattering and near-infrared (NIR) photoluminance of SWNTs allow us to track and image nanotubes in vitro and in vivo. Multiplexed multi-color NIR Raman imaging can be realized by using isotopically modified SWNTs. As many as five different SWNT Raman 'colors' have been produced and used to label and image cancer cells in vitro and tumor slices ex vivo, revealing both geometrical and molecular information of biological samples. Besides carbon nanotubes, we have also studied the biomedical applications of biocompatible nano-graphene sheet (NGS) in vitro and in vivo. Surprisingly high tumor passive uptake of NGS is observed and utilized for highly efficient photothermal therapy of cancer in mouse tumor models. Taken together, carbon nanomaterials are promising for future multimodality cancer therapy and imaging.