Synthesis and Application of Fe3O4@Au Composite Nanoparticles as Magnetic Resonance/Computed Tomography Dual‑Modality Contrast Agent

None of the molecular imaging modalities can produce imaging with both anatomical and functional information. In recent years, to overcome these limitations multimodality molecular imaging or combination of two imaging modalities can provide anatomical and pathological information.

Magnetic iron oxide nanoparticles were prepared by co‑precipitation method and then were coated with silica according to Stober method. Consequently, silica‑coated nanoparticles were amino‑functionalized. Finally, gold nanoparticles assembled onto the surfaces of the previous product. Cytotoxicity effects of prepared Fe3O4@Au nanoparticles were evaluated by 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide assay on human hepatocellular carcinoma cells. Their ability as a dual‑mode contrast agent was investigated by magnetic resonance (MR) and computed tomography (CT) imaging.

Fe3O4@Au nanoparticles were spherical undersize of 75 nm. X‑ray diffraction analysis confirmed the formation of Fe3O4@Au nanoparticles. The magnetometry result confirmed the superparamagnetism property of prepared nanoparticles, and the saturation magnetization (Ms) was found to be 33 emu/g. Fe3O4@Au nanoparticles showed good cytocompatibility up to 60 μg/mL. The results showed that the Fe3O4@Au nanoparticles have good r2relaxivity (135.26 mM−1s−1) and good X‑ray attenuation property.

These findings represent that prepared Fe3O4@Au nanoparticles in an easy and relatively low‑cost manner have promising potential as a novel contrast agent for dual‑modality of MR/CT imaging