Phytochemical-driven engineering of spinel CoFe₂O₄ nanoferrites: correlating structural, magnetic, and anticancer properties using green self-ignition synthesis

Green synthesis has emerged as an environmentally sustainable strategy for engineering multifunctional nanomaterials with enhanced biomedical performance. In this study, cobalt ferrite (CoFe₂O₄) nanoparticles were synthesized via a self-ignition route using carrot extract (Co-C) and pomegranate juice (Co-P) as eco-friendly reducing and stabilizing agents. X-ray diffraction and Rietveld refinement confirmed the formation of phase-pure inverse spinel CoFe₂O₄ with cubic Fd3̅m symmetry and lattice constants of 8.369 Å for Co-C and 8.367 Å for Co-P. Dynamic light scattering analysis revealed dominant nanoscale hydrodynamic populations centered at 11.83 nm for Co-C and 18.17 nm for Co-P, whereas intensity distributions indicated moderate magnetic agglomeration, with secondary populations extending to 286.47 and 551.47 nm, respectively. AFM analysis showed that the pomegranate-mediated ferrite had significantly lower surface roughness (R a = 0.244 nm; R q = 0.318 nm) than the carrot-mediated sample (R a = 1.04 nm; R q = 1.31 nm), indicating superior nanoscale smoothness and morphological homogeneity. FESEM and HRTEM investigations confirmed the formation of interconnected nanocrystalline ferrite architectures with extract-dependent morphology and aggregation behavior. Magnetic susceptibility measurements revealed ferrimagnetic ordering, with Curie temperatures decreasing from ∼ 829 K for Co-C to 781 K for Co-P, reflecting weakening A–B superexchange interactions induced by cation redistribution. Anticancer performance against PC-3 prostate cancer and MDA-MB-231 triple-negative breast cancer cells showed concentration-dependent cytotoxicity for both ferrite systems. Co-P nanoparticles exhibited superior anticancer activity, with IC₅₀ values of 1.2 mg/mL for PC-3 and 0.60 mg/mL for MDA-MB-231 cells, compared with 1.8 and 0.75 mg/mL, respectively, for Co-C. The enhanced cytotoxicity of Co-P was attributed to its larger surface area (538.17 m²/g), higher porosity (13.38%), and the presence of highly bioactive phytochemicals such as ellagic and protocatechuic acids. Mechanistically, the nanoparticles induced ROS-mediated oxidative stress, mitochondrial dysfunction, DNA damage, apoptosis, and autophagic stress. These findings establish green-synthesized CoFe₂O₄ ferrite nanoparticles as promising multifunctional nanoplatforms for future magnetic, catalytic, and nanomedicine applications.