Synthesis and characterization of superparamagnetic iron oxide nanoparticles functionalized with cysteine, glutathione and gold for potential biomedical applications

Full text: Superparamagnetic iron oxide nanoparticles (SPIONs), such as magnetite (Fe₃O₄), are known for their biocompatibility and applications in several areas of medicine. The present research is focused on the synthesis and characterization of SPIONs mono and bimetallic containing gold (Au). Magnetite nanoparticles (Fe₃O₄ NPs) were synthesized by co-precipitation of iron salts and coated with biocompatible molecules such as cysteine (CYS) and Glutathione (GSH), leading to Fe₃O₄-CYS and Fe₃O₄-GSH NPs, respectively. Fe-Au nanoparticles were also synthesized by reverse micelle method. The nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and ultraviolet-visible (UV-vis) spectroscopies, SQUID magnetic measurements and dynamic light scattering (DLS). The results showed that metallic and bimetallic nanoparticles have a mean diameter about of 15 nm, at solid state, and a superparamagnetic behavior at room temperature. 5,5'-dithiobis(2-nitrobenzoate) molecule (DTBN) was used to quantify free SH groups on nanoparticles surface and the amount of micromols of SH per gram of nanoparticles was calculated by the DTBN titration. The average hydrodynamic sizes of these NPs were about of 80 nm. Taken together the results suggest that coating magnetite nanoparticles with CYS and GSH leads to the formation of a stable aqueous dispersion of thiolate superparamagnetic nanoparticles and Au-Fe nanoparticles synthesis were well succeeded which shows a great potential as biomedical vehicle. (author)