Abstract：
Iron nanoparticles have been used as negative contrast agents for T2-weighted magnetic resonance imaging due to their high relaxivity and low toxicity. Gold nanoparticles possess good biocompatibility and unique optical property. In this study, we fabricated oval-shaped Fe@Au core-shell nanoparticles (oFe@Au NPs) by micro-emulsion method, and used 2-aminoethanethiol(-SH) modify the surface. Methotrexate (MTX), an anticancer drug, was further conjugated onto the oFe@Au-SH NPs. The multifunctional nanoparticles could be applied for magnetic resonance imaging (MRI), optical coherence tomography (OCT) and photothermal therapy of cancers. The analysis result of superconducting quantum interference device magnetometer (SQUID) showed that the oFe@Au NPs was superparamagnetic with a saturation magnetization value (Ms) of 13.7 emu/g. The oFe@Au NPs could shorten the T2 relaxation time of water protons and result in MRI contrast enhancement. In vitro MTT assay using mouse fibroblasts cell line (L929) was carried out and the results showed that the concentration of 500 μg/mL oFe@Au NPs did not have appreciable toxicity. UV/vis spectroscopy was used to investigate the optical property of the oFe@Au NPs. The oFe@Au NPs exhibited an absorption peak at 792 nm. We further used an 808 nm laser (2 W/cm2) to irradiate the oFe@Au NPs aqueous suspension. For 500 μg/mL oFe@Au NPs, after 360 s irradiation the temperature reached 53.1 oC. The result revealed that the oFe@Au NPs was amenable for photothermal therapy applications. Using optical coherence tomography, the three-dimensional images were clearer with higher concentration. Results of in vitro MTT assay using human colon cancer cell line (SW620) showed that only 37.9% cell survived with 500 μg/mL oFe@Au-MTX NPs and laser irradiation. In vivo study using SW620 implanted nude mouse presented promising results, and the tumors were totally eliminated in one week followed by 50 μg oFe@Au-MTX NPs injected and once 360 s 150 mW/cm2 laser irradiation.
 
Brief Bio: 
Dr. Ren-Jei Chung is an Associate Professor in the Department of Chemical Engineering and Biotechnology at National Taipei University of Technology, and also serves as the Vice Director in the Biomaterials Interdisciplinary Research Center. Dr. Ren-Jei Chung received his B.S(1999), M.S.(2001) and Ph.D.(2006) degrees in the Department of Materials Science and Engineering at National Tsing Hua University, Taiwan. During Bachelor degree, he also co-majored in the Department of Life Science; and then received the certification of Patent Engineer from National Chiao Tung University. After graduated he worked as a postdoctoral fellowship at National Tsing Hua University shortly. From February of 2007, he joined the Department of Materials Science and Engineering at National Chung Hsing University as an Assistant Professor. Since August of 2008 till now, he joined the Department of Chemical Engineering and Biotechnology at National Taipei University of Technology. Dr. Ren-Jei Chung has his research interests in Biomaterials, Biomedical Applications of Nanotechnology, Tissue Engineering and Biosensors. He has been awarded for Young Investigator Award from 2014 International Symposium of Materials on Regenerative Medicine, and Dr. Shechtman Young Researcher Award from National Taipei University of Technology in 2015.