Sodium alginate functionalized nickel ferrite nanocomposites: synthesis, physicochemical characterization, and evaluation of antibacterial, anticancer, and biocompatibility properties.

The rise of multidrug-resistant bacteria and the need for effective therapies against breast cancer highlight the demand for multifunctional nanomaterials with high biocompatibility. In this study, Nickel ferrite (NiFe₂O₄) and sodium alginate functionalized NiFe₂O₄ nanocomposites (NiFe₂O₄-SA) were synthesized via a green co-precipitation method. X-ray diffraction confirmed a cubic spinel structure, and transmission electron microscopy revealed quasi-spherical nanoparticles with sizes of 15-25 nm and uniform alginate coating. UV-Vis analysis showed a reduction in band gap from 4.44 eV to 3.13 eV, while photoluminescence spectra indicated enhanced charge carrier separation. NiFe₂O₄-SA exhibited strong antibacterial activity against Gram-negative pathogens (Klebsiella pneumoniae, Escherichia coli, Shigella dysenteriae, Pseudomonas aeruginosa, and Proteus vulgaris), with membrane disruption confirmed by microscopy. Cytotoxicity studies on MCF-7 breast cancer cells demonstrated dose-dependent inhibition with an IC₅₀ of 11.9 μg/mL, and zebrafish embryo assays confirmed excellent biocompatibility for NiFe₂O₄-SA. These findings highlight NiFe₂O₄-SA nanocomposites as promising multifunctional nanomaterials for therapeutic and biomedical applications.