Spinel copper ferrite (CuFe₂O₄) and zinc ferrite (ZnFe₂O₄) nanoparticles were synthesized using a sol-gel self-combustion technique. The structural, functional, morphological and magnetic properties of the samples were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). XRD patterns conform to the copper ferrite and zinc ferrite formation, and the average particle sizes were calculated by using a transmission electron microscope, the measured particle sizes being 56 nm for CuFe₂O₄ and 68 nm for ZnFe₂O_4. Both spinel ferrite nanoparticles exhibit ferromagnetic behavior with saturation magnetization of 31 emug⁻¹ for copper ferrite (50.63 Am²/Kg) and 28.8 Am²/Kg for zinc ferrite. Both synthesized ferrite nanoparticles were equally effective in scavenging 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) free radicals. ZnFe₂O₄ and CuFe₂O₄ nanoparticles showed 30.57% ± 1.0% and 28.69% ± 1.14% scavenging activity at 125 µg/mL concentrations. In vitro cytotoxicity study revealed higher concentrations (>125 µg/mL) of ZnFe₂O₄ and CuFe₂O₄ with increased toxicity against MCF-7 cells, but were found to be non-toxic at lower concentrations suggesting their biocompatibility.

Manganese ferrite (MnFe₂O₄) magnetic nanoparticles were successfully prepared by a sol-gel self-combustion technique using iron nitrate and manganese nitrate, followed by calcination at 150 °C for 24 h. Calcined sample was systematically characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and vibrational sample magnetometry (VSM) in order to identify the crystalline phase, functional group, morphology, particle size, shape and magnetic behavior. It was observed that the resultant spinal ferrites obtained at low temperature exhibit single phase, nanoparticle size and good magnetic behavior. The study results have revealed the existence of a potent dose dependent cytotoxic effect of MnFe₂O₄ nanoparticles against 4T1 cell lines at varying concentrations with IC₅₀ values of 210, 198 and 171 μg/mL after 24 h, 48 h and 72 h of incubation, respectively. Cells exposed to higher concentrations of nanoparticles showed a progressive increase of apoptotic and necrotic activity. Below 125 μg/mL concentration the nanoparticles were biocompatible with 4T1 cells.

Nanocrystalline magnesium ferrites (MgFe₂O₄) were produced with an average grain size of about 20 nm. Their structural, morphological, and magnetic characterizations were studied. The cytotoxic effects of MgFe₂O₄ nanoparticles in various concentrations (25, 50, 100, 200, 400, and 800 μg/mL) against MCF‐7 human breast cancer cells were analyzed. MTT assay findings suggest the increased accumulation of apoptotic bodies with the increasing concentration of MgFe₂O₄ nanoparticles in a dose‐dependent manner. Flow cytometry analysis shows that MgFe₂O₄ nanoparticles in 800 μg/mL concentration are more cytotoxic compared to vehicle‐treated MCF‐7 cells and suggests their potential utility as a drug carrier in the treatment of cancer.