ABSTRACT
298Spinel ferrite nanoparticles (NPs) exhibit unique optical, electronic, and magnetic properties which have made them NPs of greater interest. The spinel ferrite NPs have high permeability, magnetization, good saturation, and they have no preferred direction of magnetization. Magnetic NPs have a unique property that makes them to be applied in nanomedicine—they can address targets, such as cellular therapy, tissue repair, drug delivery, magnetic resonance imaging (MRI), and nanobiosensors. These applications require high values of magnetization of NPs and the size must be <100 nm with uniform chemical and physical properties. Over the years, iron oxide, especially magnetite (Fe3O4), was the most investigated magnetic NP. The small magnetic NPs allow delivery of an antibiotic when targeting certain organs such as brain and kidney. The Fe3O4 NPs coated with silver improves bacterial activity. Cobalt-ferrite (Co-Fe) NPs which belong to the crystal family of spinel ferrites (MFe2O4), possess larger magnetic anisotropy than other ferrites (e.g., magnetite) making them more attractive for nanotechnology- based therapies. A significant decrease in cytokinesis-blocked proliferation index and increase in the frequency of micro nucleated binucleated lymphocytes are shown with 5.6 nm Co-Fe NPs. Coating the surface of these NPs leads to a fourfold reduced level of toxicity. The substitution of zinc and copper in Co-Fe NPs significantly improves antibacterial activity. A coppersubstituted Co-Fe NP exhibits the most effective contact biocidal property among all of the NPs. Zinc and copper-substituted Co-Fe NPs have high potential to be used in drug delivery systems as well as in other biomedical and biotechnology applications.
