| Summary: | 碩士 === 長庚大學 === 化工與材料工程研究所 === 97 === The purpose of this study was to prepare Fe3O4/polypyrrole (Fe3O4/PPy) nano-composites with core-shell structure. The nano-composites were first synthesized by co-precipitation of Fe3O4 nano-particles with the size controlled by β-cyclodextrin (β-CD), and then encapsulated with PPy by oxidation polymerization. By the infrared spectrometer (FT-IR) and X-ray diffraction instrument (XRD) analysis showed that nano-composites prepared by the success of Fe3O4/PPy. The particle sizes of Fe3O4 and Fe3O4/PPy were 5-20 nm and 15-40 nm, respectively, as measured by field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). showed less aggregation due to the particle surfaces covered by PPy. Through the superconducting quantum interference device magnrtometer (SQUID) analysis, Fe3O4 covered by PPy (PPy/Fe3O4 molar ratio was 3/1 and 5/1), the saturation magnetization of Fe3O4/PPy composites was decreased from 74.7 emu/g to 52.7 emu/g and 45.8 emu/g, respectively. Through the Dynamic Light Scattering (DLS) analysis, the measured average size of Fe3O4 was higher due to the particle aggregation by static magnetic force. However, the average sizes of Fe3O4/PPy decreased with the increasing of PPy, which was due to the blocking of doping type PPy and reducing static magnetic force between Fe3O4 particles and resulted in less particle aggregation. Through toxicity test and checked with optical microscope, the little variation of morphologies and numbers of human umbilical vein endothelial cells (HUVEC) co-cultured with and without Fe3O4/PPy nano-composites were observed. With the further recombinant tissue plasminogen activator (rt-PA) grafted in the nano-composites, the grafting ratio could be higher than 96% measured by protein assay. The thrombolytic ratio measured by static thrombolysis was increased from 39.72% to 46.83 % with the treatment of rt-PA-Fe3O4/PPy composite under the guide of external magnetic field. The clots of 2 mm × 5 mm were used for the in vitro thrombolysis analysis. The thrombolytic rate analyzed by dynamic thrombolysis was 12 minutes faster than that of pure rt-PA without external magnetic field applied.
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