Folic acid-targeted magnetic Tb-doped CeF3 fluorescent nanoparticles as bimodal probes for cellular fluorescence and magnetic resonance imaging

摘要

Magnetic fluorescent nanoparticles (NPs) have great potential applications for diagnostics, imaging and therapy. We developed a facile polyol method to synthesize multifunctional Fe3O4@CeF3: Tb@CeF3 NPs with small size (<20 nm), high water solubility and good biocompatibility. The NPs were modified by ligand exchange reactions with citric acid (CA) to obtain carboxyl-functionalized NPs (Fe3O4@CeF3: Tb@CeF3-COOH). Folic acid (FA) as an affinity ligand was then covalently conjugated onto NPs to yield Fe3O4@CeF3: Tb@CeF3-FA NPs. They were then applied as multimodal imaging agents for simultaneous in vitro targeted fluorescence imaging and magnetic resonance imaging (MRI) of HeLa cells with over-expressed folate receptors (FR). The results indicated that these NPs had strong luminescence and enhanced T-2-weighted MR contrast and would be promising candidates as multimodal probes for both fluorescence and MRI imaging.