| Summary: | 碩士 === 國立臺北科技大學 === 化學工程與生物科技系生化與生醫工程碩士班 === 104 === In this study we prepared Co@Au core-shell nanoparticles (Co@Au NPs) by microemulsion method. Silver nitrate was added for secondary preparation to form Co@Au core-shell nanorods (Co@Au NRs). An anticancer drug, methotrexate (MTX), was further grafted. The Co@Au-MTX NRs were expected to be multifunctional and suitable for magneto-thermal therapy, photo-thermal therapy, image and drugs delivery in cancer therapy.
XRD, ICP, EDS, ESCA, SQUID, TEM, UV-VIS and FTIR were used to characterize the properties of Co@Au core-shell nanoparticles and nanorods. High-frequency induction heating machine (HF-IHM ) and 808 nm laser were used to measure the heating efficiency. Magnetic resonance imaging (MRI) and optical coherence tomography (OCT) were utilized to evaluate the feasibility for image contrast agent. In vitro tests were carried out to evaluate the biocompatibility with three cell lines (L929, C6, SW620). 808 nm laser irradiation was further applied to verify the concept of photo-thermal therapy.
The results of XRD, ICP, EDS investigations showed that the Co@Au NPs were composed of cobalt and gold elements with a molar ratio of Co to Au 2:1. SQUID measurement confirmed that Co@Au NPs were superparamagnetic at 350 K and the saturated magnetization was 6 emu/g. After 10 minutes treatment of HF-IHM, the temperature of 7 mg/mL Co@Au NPs solution increased from 26 oC to 58.5oC. The relaxation rate (r2) was 23.723 mM-1s-1 by MRI observation. Through UV-vis measurement, Co@Au NRs had adsorption peaks around 550 nm and 790 nm. TEM micrographics revealed the shape was rod, and the molar ratio of Co to Au was 1:120 by ICP and EDS investigations. After 10 minutes treatment of 808 nm laser, the temperature of 500 µg/mL Co@Au NPs solution increased from 22 oC to 46oC. The relaxation rate (r2) of Co@Au NRs was 2.3887 mM-1s-1 by MRI observation. FTIR spectrum was used to confirm the successful surface grafting of MTX. Finally, the results of in vitro tests showed that Co@Au NRs had better biocompatibility than Co@Au NPs for L929 cells. Co@Au NRs were neither cytotoxic to cancer cells, but Co@Au-MTX NRs were. Using TEM, Co@Au NRs were found to attach onto the membrane surface of SW 620 cell after 12 hr treatment. With 500 µg/mL Co@Au/-MTX NRs treatment, the residual cell viability after 808 nm laser irradiation was decreased gradually with irradiation time. Therefore, concluding above the results, the Co@Au NRs have great potential in biomedical applications especially for cancer theranostic.
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