| Summary: | 碩士 === 國立中正大學 === 物理系 === 92 === Recently, we have successfully synthesized polyethyleneimin (PEI)-coated magnetic iron oxide nanoparticles and have associated these nanoparticles with retroviral vectors to develop new magnetic retroviral vectors for enhancing gene therapy. We have demonstrated the magnetic retroviral vectors can accurately deliver to specific target sites by guiding of an external magnetic field. In addition, the gene transduction and expression were enhanced by an external magnetic filed. To further improving our system it requires stronger magnetic force of nanoparticles. In this investigation we synthesized and characterized the properties of FeCo and FeNi alloy nanoparticles. These two types of nanoparticles which have higher saturation magnetization (Ms) and lower coercivity (Hc), easily prepare defined the particle sizes and narrow size distributions through well controlling the synthesis parameters. In this study, we studied to envelope polycationic PEI polymers and Au over these particle surfaces to form magnetic colloids and core-structure. Measurements of high-resolution transmission electron microscopy (HRTEM) showed that the sizes of magnetic nanoparticles are ranging from 4 to 30 nm which depend on the fabrication methods and process parameters. After the PEI coating, we found the sizes of magnetic colloids are around 200 nm. The magnetic properties of PEI-coated and Au-coated nanoparticles were determined on a vibrating sample magnetometer (VSM). In association with the application of magnetic guidance, these PEI-coated magnetic nanoparticles were tested to have the localization effect on the drug administration. The in-vivo biological applications of these PEI-coated nanoparticles are in progress.
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