Monodisperse magnetites anchored onto carbon nanotubes: a platform for cell imaging, magnetic manipulation and enhanced photothermal treatment of tumors

Abstract

In this paper, a facile solvothermal synthesis method was developed to prepare monodisperse magnetites anchored onto multi-walled carbon nanotubes (MWNTs). The pristine MWNTs were treated with a mixture of concentrated sulfuric and nitric acids. The oxidized MWNTs (o-MWNTs) had abundant carboxylic groups on the surface, which have a strong ability to chelate metal ions like Fe³⁺. The obtained MWNTs–Fe₃O₄ nanomaterials allowed π–π stacking of fluorescein isothiocyanate (FITC) to monitor inside living cancer cells by fluorescence imaging. Cells labeled with MWNTs–Fe₃O₄ nanomaterials could be efficiently manipulated by a magnetic field due to the large magnetic moment of the iron oxide domain in the nanocomposites. The MWNTs–Fe₃O₄ nanomaterials have been demonstrated to be effective for in vivo photothermal treatment of tumors using mice implanted with human U87 tumors as a model.