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1220-BB01-02

The Surface Modification of Nanocrystals for Biological and Environmental Applications Chunjiao Zhou1, Pengfei Rong2，Wei Wang2, Wenjie Zhang1, Qiang Wan1 and Bingsuo Zou1, 3* 1

State Key Lab of CSBC, Micro-Nano Center, Hunan University, Changsha, 410082, China;

2

The Radiological Department Of Third Xiang-Ya Hospital, Central South University, Changsha, 410013, China;

3

School of MSE, Beijing Institute of Technology, Beijing 100081, China..

ABSTRACT Superparamagnetic nanoparticles can find many applications in different fields with greener techniques. The Fe3O4 nanoparticles less than 10nm coated with humic acid were synthesized by a chemical co-precipitation technique with cheap and environmental friendly iron salts and humic acid. The as-synthesized products were highly soluble in water. The efficacy for liver Magnetic resonance imaging (MRI) contrast agent was investigated by using it to the live rat and tumor-bearing rabbit models, on a conventional clinical 1.5 T MRI facility. Moreover the Fe3O4 –HA composite used in the Methylene Blue adsorption in neutral aqueous solution was studied too with high efficiency. The experimental results showed that the humic acid coated Fe3O4 superparamagnetic nanoparticles were suitalbe not only for liver MRI contrast agent, but also as adsorbents for removal of cationic organic dyes from neutral water.

INTRODUCTION Superparamagnetic iron oxide nanoparticles with excellent water solubility and high magnetization values have recently attracted a great deal of attention due to their potential biological applications [1-5], such as, bioseparation, biosensor, biocatalysis, hyperthermia, MRI contrast enhancing and specific cell labeling and tracking or even treatiment. Meanwhile, their applications in wastewater treatment have aroused more and more concerns [6-7], because magnetic separation techniques are generally superior to filtering or centrifugation based purification techniques, as magnetic nanoparticles could be easily extracted from the solution with high selectivity and efficiency by applying an external magnetic field.

MRI is an imaging modality used to visualize the biological events in living organisms with noninvasive, high spatial resolution and three-dimension examination. And it can display both normal anatomy and various pathologies, including tumors. However, the primary disadvantage of MRI is its low sensitivity. In order to overcome this disadvantage, signal amplification strategies such as using of contrast agents are established to generate higher contrast from the surrounding tissue [4, 5, 8-9]. The superparamagnetic iron oxide nanoparticles are very attractive contrast agents because they are shown to be effective in enhancing MRI contrast and with low cytotoxicity [10]. The iron oxide nanoparticles usually generate strong transverse (T2) negative contrast in MRI and are visualized with T2-weighted images. Commercially available superparamagnetic iron oxide nanoparticles MRI contrast agents are usually stabilized with biocompatible mac