| Due to the small size effect, quantum effect and surface effect, nano-Fe3O4has some special properties such as high magnetic saturation, superparamagnetism, low Curie temperature and etc. As a result, Fe3O4is worth of use in some kinds of fileds including machinery, information, biomedicine and etc. At present, there have been many researches about synthesis, morphology control, functionalization of Fe3O4. However, particularly in biomedicine, more requirements are needed such as biocompatibility, stability and responsiveness. In this paper, coprecipitation is choosed to synthetize Fe3O4with some modification. Water-soluble and oil-soluble nano-Fe3O4particles were prepared, and then were combined with mesoporous SiO2as composite particles which were functionalized furthermore. The materials were characterized with IR, XRD, zeta potential, TEM and etc. The more detals are as follows:(1) The nano-Fe3O4particles modified by sodium citrate as the seeds, cetyl trimethyl ammonium bromide (CTAB) as template, and the tetraethoxysilane (TEOS) as silicon source, the mesoporous magnetic silica naonoparticles were synthetized. And then the composite particles were modified with3-(glycidoxypropyl) trimethoxvsilane (KH-560) and polyethylenimine(PEI) in sequence. The size of the obtained mesoporous magnetic silica naonoparticles was about100nm. The BET surface area was73.4m2/g, and the magnetic saturation was21.6emu/g. The best pH of adsorption to methyl orange and methylene blue was3and8respectively. The adsorption dynamics matched the second order kinetic model well. And the isothermal curve accorded with the Freundlich model, indicating that the the process was based on physical adsorption.(2) Cetyl trimethyl ammonium bromide (CTAB) as template, the pluronic F127as co-template, and the tetraethoxysilane (TEOS) as silicon source, the mesoporous silica grafted with amino-group was synthetized. By electrostatic attraction between amino of SiO2and carboxyl of Fe3O4, the SiO2/(Fe3O4/PEI)n particles were prepared basing on the formation of Fe3O4and PEI on the nonplanar of SiO2layer by layer. The particles were found stimuli-responsive to pH and ionic strength. And with the fat-soluble ibuprofen (IBU) as drug molecular, the drug release results showed that the release efficiency was fast with low pH while the release efficiency was suppressed with the low salt, and the temperature influence was not as obvious as pH and ionic strength.(3) The oil-soluble Fe3O4was prepared with oleic acid, and then was transferred to the water with CTAB by solvent evaporation method, which was stabilized by surfactant bilayers (OA/CTAB). When the Fe3O4particles were mixed with the F127solution, they were able to get access to the micelle. Meanwhile the free CTAB moleculars as templates, TEOS as silicon source, the mesoporous Fe3O4@mSiO2were prepared. Furthermore, the heterogeneous Fe3O4@SiO2-NH2/Au/lips particles were synthetized by futher modifications, which were found stable in neutral environment. Drug release study demonstrated that pH and temperature affected the process differently. The results showed that the pH was more obvious when the temperature was lower than phase-transition temperature (Tm) of liposome, while the temperature was more obvious when the temperature was higher than Tm of liposome. Finally, biotoxicity of different composite particles were dicussed, and the conclusion was drawn that the biotoxicity of Fe3O4@SiO2-NH2、Fe3O4@SiO2-NH2/Au、2/Au/lips decreased in turn. |
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