Facile Synthesis of Folic Acid-Modified Iron Oxide Nanoparticles for Targeted MR Imaging in Pulmonary Tumor Xenografts

The purpose of this study was to develop folic acid (FA)-modified iron oxide (Fe3O4) nanoparticles (NPs) for targeted magnetic resonance imaging (MRI) of H460 lung carcinoma cells. Water-dispersible Fe3O4 NPs synthesized via a mild reduction method were conjugated with FA to generate FA-targeted Fe3O4 NPs. The specificity of FA-targeted Fe3O4 NPs to bind FA receptor was investigated in vitro by cellular uptake and cell MRI and in vivo by MRI of H460 tumors. The formed NPs displayed good biocompatibility and ultrahigh r (2) relaxivity (440.01/mM/s). The targeting effect of the NPs to H460 cells was confirmed by in vitro cellular uptake and cell MRI. H460 tumors showed a significant reduction in T-2 signal intensity at 0.85 h, which then recovered and returned to control at 2.35 h. The results indicate that the prepared FA-targeted Fe3O4 NPs have potential to be used as T-2 negative contrast agents in targeted MRI.