The fabrication of silica/iron oxide/gold nanotubes and Gd2O(CO3)2•H2O/silica/gold hybrid particles as bifunctional materials for simultaneous MR imaging and photothermal therapy

• Main Authors: Fang-Yu Jhang, 張芳瑜
• Other Authors: Chen-Sheng Yeh
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/69420577161689216136

碩士 === 國立成功大學 === 化學系碩博士班 === 96 === In this study, we fabricated silica/iron oxide/gold nanotubes and Gd2O(CO3)2.H2O/silica/gold hybrid particles as bifunctional materials for simultaneous MR imaging and photothermal therapy. Silica/iron oxide/gold nanotubes have been prepared by firstly using water-soluble Na2SO4 nanowires as a soft template to obtain silica nanotubes, then incorporating iron oxide nanoparticles and Au seeds with the surface of silica nanotubes, and finally growing of gold shell. As can be observed in UV-vis spectra, these materials can absorb the near infrared (NIR) radiation due to the existence of gold shells. Because of combining superparamagnetic iron oxide nanoparticles, the materials were served as MRI contrast agents. The results showed the value of relaxivity r2 is 34.30 s-1mM-1. The cytotoxicity of the Silica/iron oxide/gold nanotubes were also examined with A549 lung cancer cells which overexpress EGFR by using WST-1 assay, and the results showed their good biocompatibility. The performance on photothermal cancer destroying has been demonstrated on A549 cells with a NIR laser after targeting anti-EGFR antibody-conjugated Silica/iron oxide/gold nanotubes. The selectivity targeting leads to different photothermal destruction between A549 and CL1-0 cells, while A549 can be readily destructed by photothermal method compared to CL1-0 with less EGFR expression. Another multifunctional Gd2O(CO3)2.H2O/silica/gold hybrid particles with a core/shell structure have been designed and synthesized. Silica shells could be synthesized by hydrolysis and condensation of tetraethoxysilan (TEOS) on the surface of Gd2O(CO3)2.H2O nanoparticles. The amino functional groups on the surface of Gd2O(CO3)2.H2O/silica were functionalized with 3-aminopropyl-triethoxysilane(APS). For further shell-growth on the gold seeds, gold seeds were previously decorated on the silica layer in gold growth solution, and formaldehyde was added into solution to reduce gold ions on the seeds. The thickness of Au shell on the Gd2O(CO3)2.H2O/silica particles can be systematically tuned by tailoring the amount of HAuCl4 in growth solution. We found the significant variations in UV-vis spectra and the absorbance peaks were depended on the thickness of Au shells.