Synthesis of Three-Layered Magnetic Based Nanostructure for Clinical Application


Laser and Nanobiophotonic Lab., Biomaterials Group, Faculty of Biomed. Eng., Amir Kabir University of Technology, Tehran, I.R. Iran


The main objective of this research was to synthesize and characterize gold-coated Fe3O4 /SiO2 nanoshells for clinical applications. Magnetite nanoparticles (NPs) were prepared via co-precipitation. The results showed that smaller particles can be synthesized by decreasing the NaOH concentration, which in our case this corresponded to 35 nm by using 0.9 M of NaOH at 750 rpm. The NPs were then modified with a thin layer of silica using Stober method. The surface of Fe3O4 /SiO2 nanoshells was then terminated with amine groups with 3-aminopropyltriethoxysilane (APTS) in ethanol. Small gold colloid (1-3 nm) were adsorbed on the particle surface via the interaction between the negative charge on the Au nanoparticles and the positive charge of -NH3 on the SiO2 shell modified by APTS. Gold nanoshell formation, morphology and dimensions were assessed with a UV-Vis spectrophotometer, atomic force microscope (AFM), and transmission electron microscope (TEM). The synthesized nanostructures exhibited an absorption peak at ~550 nm with a magnetization value of 1.3 emu/g. Based on the X-ray diffraction (XRD) results, three main peaks of Au were identified. The formation of each layer of a nanoshell is also demonstrated by Fourier transform infrared (FTIR) results.