Structure And Morphology Control Of Iron Oxide Nanoparticles And Preperation And Charaterization Of Drug-loaded Magnetic Fluid

Iron oxide nanoparticles, as a kind of low-cost material with broad chromatogram and non-toxicity, have prospective applications in many areas. For its unique magnetic properties, magnetic iron oxide nanoparticles show mangy advantages and can be used as pigment, magnetic recording materials and catalysis materials. Surfactant plays an important role in the preparation of iron oxides by controlling their structures and morphologies. Recently, the application of magnetic iron oxide nanoparticles in biomedicine is intensively interested. Here we worked in these fields and got following results:Firstly, we presented a simple coprecipitation way to prepare Fe₃O₄ nanoparticles andα-FeOOH nanorods in alcohol/water media in the presence of Pluronic triblock copolymer F127. The morphologies and structures of samples were investigated as the volume ratio of alcohol to water was changed. By means of adjusting the volume ratio of alcohol to water from 0:1, 1:1 to 5:1, gradual transformation of phase and morphology from Fe₃O₄ nanoparticles of about 15nm toα-FeOOH nanorods with diameters around 20nm and lengths up to 200-300nm was clearly observed through X-ray powder diffraction analysis and transmission electron microscopy observations. Possible mechanism was discussed. F127 was found to play an important role in the formation ofα-FeOOH nanorods as a structure-directing agent.Secondly, we prepared Fe₃O₄ nanoparticles and irregularβ-FeOOH nanosheets in alcohol/water media in the presence of SDBS. The morphologies and structures of samples were investigated during the changes of volume ratio of alcohol to water and the concentration of SDBS. When SDBS: Fe=1:72 (molar ratio), by means of adjusting the volume ratio of alcohol to water from 0:1, 1:1 to 5:1, gradual transformation of phase and morphology from Fe₃O₄ nanoparticles to irregularβ-FeOOH nanosheets were clearly observed through X-ray powder diffraction analysis and transmission electron microscopy observations. As molar ratio of SDBS: Fe raised, more SDBS prevented the nucleus growth. As comparison, we can only get Fe₃O₄ nanoparticles in alcohol/water media in the presence of CTAB. SDBS was found to play a important role in the formation of irregularβ-FeOOH nanosheets. XRD and TEM were used in characterization.Thirdly, by loading doxorubicin (DOX) on 5-carboxyl-fluorescein (FAM) labeled AGKGTPSLETTP peptide (A54) coupled starch-coated iron oxide nanoparticles (SIONs), we prepared a novel aqueous drug delivery system with both magnetic and biomolecular targeting, which was specific to human hepatocellular carcinoma cell line BEL-7402. The saturated extent of adsorption reached 2.0 mg DOX / mg A54-SIONs at 28℃, which provided a rather high dose of DOX loading for application. 68% of DOX was desorped during 60 hours in PBS buffer (pH=7.4), which was a slow-release process. Tests in vitro demonstrated the specificity of DOX-loaded A54-SIONs to BEL-7402 cells. The microscopy images proved that DOX-loaded A54-SIONs were successfully targeted to tumor tissue of nude mice with an external magnetic field in vivo. Mitogenic assay in vitro showed higher cytotoxic efficiency of DOX-loaded A54-SIONs against hepatocellular carcinoma cells BEL-7402 than DOX-loaded SIONs with simple magnetic targeting. This new drug delivery system showed a potential application in therapeutics of human tumor.