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Size-controlled synthesis of superparamagnetic iron oxide nanoparticles and their surface coating by gold for biomedical applications

Maleki, H ; Sharif University of Technology | 2012

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  1. Type of Document: Article
  2. DOI: 10.1016/j.jmmm.2012.06.045
  3. Publisher: 2012
  4. Abstract:
  5. The size mono-dispersity, saturation magnetization, and surface chemistry of magnetic nanoparticles (NPs) are recognized as critical factors for efficient biomedical applications. Here, we performed modified water-in-oil inverse nano-emulsion procedure for preparation of stable colloidal superparamagnetic iron oxide NPs (SPIONs) with high saturation magnetization. To achieve mono-dispersed SPIONs, optimization process was probed on several important factors including molar ratio of iron salts [Fe 3 and Fe 2], the concentration of ammonium hydroxide as reducing agent, and molar ratio of water to surfactant. The biocompatibility of the obtained NPs, at various concentrations, was evaluated via MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay and the results showed that the NPs were non-toxic at concentrations <0.1 mg/mL. Surface functionalization was performed by conformal coating of the NPs with a thin shell of gold (∼4 nm) through chemical reduction of attached gold salts at the surface of the SPIONs. The Fe 3O 4 core/Au shell particles demonstrate strong plasmon resonance absorption and can be separated from solution using an external magnetic field. Experimental data from both physical and chemical determinations of the changes in particle size, surface plasmon resonance optical band, phase components, core-shell surface composition, and magnetic properties have confirmed the formation of the mono-dispersed core-shell nanostructure
  6. Keywords:
  7. Au ; Fe 3O 4 ; Superparamagnetic Nanoparticle ; Core/shell ; Mono-dispersity ; Nanoemulsion ; Superparamagnetic nanoparticles ; Surface Functionalization ; Ammonium compounds ; Biocompatibility ; Bromine compounds ; Emulsions ; Gold ; Iron oxides ; Magnetic properties ; Medical applications ; Nanoparticles ; Salts ; Saturation magnetization ; Shells (structures) ; Superparamagnetism ; Surface active agents ; Surface chemistry ; Surface plasmon resonance ; Gold coatings
  8. Source: Journal of Magnetism and Magnetic Materials ; Volume 324, Issue 23 , November , 2012 , Pages 3997-4005 ; 03048853 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0304885312005586