Abstract: Objective To research the preparation of magnetic iron oxide nanoparticles and their distribution in the SD rat. Methods A organic phase process is used for making high-quality monodisperse hydrophobic Fe₃O₄ nanocrystals through the high temperature decomposition of Fe(acac)₃ and a long-chain alcohol in autoclave reactor. Then water-soluble iron oxide nanoparticles (WION) were prepared by mixing with a bipolar surfactant,2,3 dimercaptosuccinic acid (DMSA). Results The nanoparticles with mean sizes 10 nm are Fe₃O₄ nanocrystal. 24 h after tail vein injection of WION 0.5 ml(1mg/ml solution), the WION mainly concentrated in the spleen and liver, kidneys and lungs followed. Conclusion Successfully prepared Fe₃O₄ nanoparticles through pyrolysis, and it has good surface morphology. Further modificated its surface by DMSA, can obtained a good dispersion of the WION.

Key words: Fe₃O₄, Water-soluble iron oxide nanoparticles (WION), Transmission electron microscope