Unleashing the multifunctionality of biocompatible superparamagnetic spinel NiFe2O4 nanoparticles: exploration of its efficacy towards leukemic cells and MDR pathogenic bacteria

Abstract

NiFe₂O₄ nanoparticles (NiFe₂O₄ NPs) was prepared by a cost-effective co-precipitation method. Cation distribution suggested that a small fraction of Ni²⁺ cations transferred to the octahedral position due to the nano-regime. X-ray diffraction (XRD) confirmed the occurrence of two phases, and the %contribution of each phase was determined by Rietveld analysis. The sample exhibited an almost superparamagnetic character (negligible coercivity) at room temperature and did not show any Morin transition, although the α-Fe₂O₃ phase was present. The Mössbauer spectra at 300 K and 77 K showed complex hyperfine structures, with a paramagnetic doublet and broadened magnetic components. The spectra suggested the presence of hematite (8%) and Ni ferrite nanoparticles, but superparamagnetic relaxation prevented accurate Fe site estimation. The synthesized NiFe₂O₄ NPs exhibited an IC₅₀ value of 21.91 μg mL⁻¹ in terms of anticancer efficacy against the chronic myeloid leukemia (CML) cell line K562. Oxidative stress in K562 cells was elevated after treatment with NiFe₂O₄ NPs, as demonstrated by the evaluation of the intracellular redox status, oxidative stress indicators, and the antioxidant activity of enzymes. The fluorescence imaging approach revealed that increased amounts of reactive oxygen species (ROS) cause DNA damage, ultimately leading to the death of leukemic cells. NiFe₂O₄ NPs were further assessed against MDR pathogenic Escherichia coli and Staphylococcus aureus, revealing that doses of 50 and 70 μg mL⁻¹, respectively, exerted significant inhibitory effects on bacterial growth with concurrent biofilm inhibitory properties. Following the exposure of leukemic and bacterial cells with NiFe₂O₄ NPs, the determined therapeutic concentrations were analysed for cytotoxicity against healthy human PBMCs and RBCs. The assays indicated that none of the therapeutic concentrations exhibited toxic effects.