Yolk-type Au@Fe_3O_4@C nanospheres for drug delivery, MRI and two-photon fluorescence imaging

摘要

Nearly monodispersed yolk-type Au@Fe_3O_4@C nanospheres with hollow cores of 50 nm in diameter were prepared through coating Au@SiO_2 nanoparticles with Fe_3O_4@C double layers, followed by dissolving SiO_2. The cytotoxicity of the nanospheres was evaluated by MTT assay, demonstrating a high biocompatibility. The yolk-type nanospheres show a high DOX loading content of 1237 mg g ~(-1). The coexistence of Fe_3O_4 and Au also makes the nanospheres as dual probes for MR imaging with a specific relaxivity (r _2~*) of 384.38 mM~(-1) s~(-1) and optical fluorescence imaging using a near-infrared (NIR) excitation. This journal is