synthesis of three-layered magnetic based nanostructure for clinical application

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.