engleski

A Coprecipitation Synthesis and Modification of Magnetic Spinel Ferrite CoFe2O4 Nanoparticles with Gold

The magnetic cobalt ferrite nanoparticles (CoFe2O4) with an average diameter from 10 to 80 nm are important because of their wide application, especially in biomedicine, where they are used as the MRI contrast enhancers, for a drug delivery and magnetic hyperthermia. The aim of this study is to synthesize the cobalt ferrite nanoparticles with a desired particle size and to monitor the effects of certain reaction parameters, which are mentioned bellow. The cobalt ferrite nanoparticles were synthesized by the coprecipitation method, whose main disadvantage is the control of a nanocrystal size. To solve that problem, it is necessary to achieve an accurate control of different reaction conditions, such as the mixing order of synthesis components, reaction temperature, and a reaction pH value. A nanoparticle modification with nitric acid and gold does not only provide stability to the nanoparticles in solution but it also assists to the binding of various biological ligands to a nanoparticle surface. The covering of the synthesized nanoparticles with a layer of gold is achieved by a reduction of HAuCl4 in the presence of a strong reduction agent. The synthesized nanoparticles were characterized by a dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), electrophoretic light scattering (ELS), and thermogravimetric analysis (TGA). The obtained results illustrate that the smaller particles are formed at a lower temperature. The FT‐IR spectra confirmed the binding of the NO2 functional group onto the nanoparticle surface, which has a great influence on the suspension stability. Also, by lowering the suspension’s pH value, the amount of amorphous substance is reduced, and the TEM images show that the cobalt ferrite nanocrystals without amorphous contaminants are present at pH 3. A future goal of this work is to apply the gold‐coated cobalt ferrite nanoparticles as nanosensors.

cobalt ferrite ; modification ; gold ; reaction parameters

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