Magnetic Nanoparticles: Preparation,Surface Modification And Adsorption Of Reduced Glutathione

Magnetic nanoparticles have high potential applications in biomedical fields such as enzyme immobilization , drug targeting , cell and DNA separation . For those applications , it demands the magnetic nanoparticles having good dispersity , uniform particle size , stable chemical property , and excellent biocompatibility . So it is significant to study preparation of monodisperse magnetic nanoparticles , surface modification of magnetic nanoparticles and adsorption of biological molecule on magnetic particles . We have done some research works on the three following items:Firstly , sodium oleate, ferric chloride, oleic acid and liquid paraffin as reaction materials were used to prepare magnetic nanoparticles in high temperature organic solution . Results showed that the main crystal of sample was Fe₃O₄ .The size of Fe₃O₄ nanoparticles with spherical morphology is about 30nm and the magnetic particles can disperse well in organic solution .Secondly , sodium oleate was used as surface modification agent to modify the surface of Fe₃O₄ nanoparticles prepared in high temperature organic solution . Parameters of the experiment such as temperature, pH value , concentration of sodium oleate and content of magnetic particles in organic phase were investigated and results showed that the method was effective in transferring Fe₃O₄ nanoparticles from organic phase to aqueous solution and the maximum ratio of Fe₃O₄ nanoparticles transferred was as high as 86% . After surface modified , Fe₃O₄ nanoparticles were hydrophilic and when it's content in aqueous solution was low , could stably disperse in aqueous solution for a long time .Thirdly , SiO₂/γ-Fe₂O₃ nanocomposites prepared by reverse microemulsion were core-shell structure and dispersed well in solution . The saturated magnetization of the nanocomposites was 58.38 emu · g^-1.The extent of reduced glutathione adsorbed on SiO₂/γ-Fe₂O₃ nanocomposites was so high that it must be a multilayer adsorption . Thermodynamic calculating showed that reduced glutathione adsorbed on core-shell structure SiO₂/γ-Fe₂O₃ magnetic nanocomposites was an endothermic spontaneous, entropy increasing and endothermal process .