LAUSR

Abstract In this study, surface modification of iron oxide (magnetite) nanoparticles through annealing with eucalyptus leaves, a benign source of carbon, was accomplished. Magnetite (Fe3O4) nanoparticles (NPs) and eucalyptus leaves were used as precursors to prepare iron oxide-carbon composite NPs by annealing the base Fe3O4 NPs at different temperature (500, 600, 700, and 800 °C) in air. The variations in their crystalline structure were confirmed by X-Ray diffraction, chemical groups and composition by Fourier transform infrared spectroscopy, and elemental abundance by scanning electron microscopy images coupled with energy dispersive X-ray techniques. For their conformational analysis, transmission electron microscopy and dynamic light scattering methods were used, and the mean particle size ranged between 10 and 42 nm increasing with annealing temperature. Behavioral changes in the properties of iron oxides-carbon composite NPs were observed due to presence of carbon. The presence of carbon changed the chemical and physical properties of the composite NPs, which became fluorescent and hydrophilic while retaining their superparamagnetic character. The composites were proven to be biocompatible through MTT assay on MDCK-II cell lines. These superparamagnetic, fluorescent, biocompatible composite NPs can be used in biomedical applications where Fe3O4 NPs proved deficient due to their non-hydrophilic character. Thus, a novel class of nanomaterials has been found.