Transferrin-Conjugated Superparamagnetic Iron Oxide Nanoparticles as In Vivo Magnetic Resonance Imaging Contrast Agents

Poly(ethylene glycol) (PEG)/poly(ethylene imine) (PEI) modified superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized by the thermal decomposition of iron (III) acetylacetonate (Fe(acac)(3)) in PEG containing PEI. Transferrin (Tf) was employed to functionalize SPIONs. The potential of Tf-SPIONs as brain magnetic resonance (MR) imaging contrast agents was explored by using Kunming mice as an animal model. The in vivo experiments revealed that Tf-SPIONs exhibited an enhanced contrast time as compared with the PEG-SPIONs and PEG/PEI-SPIONs. Tf-SPIONs exhibit promising potential for bioimaging applications because of their advantages of dispersibility in water, low cytotoxicity and long circulation time in blood.