Objective:To explore the possibility as antisense gene carriers.Preparation of super paramagnetic iron oxide MR contrast agent Iron oxide nanoparticles and test their physical and Magnetic Properties.Methods:the iron oxide nanoparticles is obtained by means of Co-precipitation method

its structure is analyzed by X-ray powder diffraction method

its size and distribution is measured by transmission electron microscope

and its Susceptibility is measured by Vibrating Sample Magnetometer dollars.Results:Testing after dextran-coated particle diameter overall

the size is20～35nm

core diameter of around is 5nm

These particles possessed some characteristics of super paramagnetic.Relaxation rate Of the sample is 0.155×106/(mol·sec) and quality saturation magnetic intensity is 69.42162emu/g Fe.Conclusion:the sample possessed the advantages of small size

dispersed

super-paramagnetic

so it could be used as an anti-gene carriers.