Ce-Nd Co-substituted nanospinel cobalt ferrites: An investigation of their structural, magnetic, optical, and apoptotic properties

In this study, Nd3+ and Ce3+ co-substituted Co ferrite nanoparticles (NPs) were prepared using a sonochemical approach. The simultaneous substitution of Nd3+ and Ce3+ into CoFe2O4 nanoparticles (NPs) affected the structure, magnetic properties, and cation distribution. The structural parameters were investigated and calculated via XRD studies. The nanocrystalline morphology was identified by SEM along with EDX and TEM. The appearance of two vibration bands correlated to the T-d and O-h group relevant to the spinel ferrite lattice were confirmed by Fourier-transform infrared spectroscopy (FT-IR). Magnetization analyses were conducted at room temperature (300K; RT) and low (10K) temperatures. Different magnetic parameters including the remanence (M-r), coercivity (H-c), saturation magnetization (M-s), squareness ratio (SQR = M-r/M-s), and magnetic moment (n(B)) were deduced and discussed. The results demonstrated a superparamagnetic (SPM) nature in the x = 0.00 sample at RT. However, the other samples (0.03 <= x <= 0.20) exhibited ferromagnetic (FM) natures. At 10K, all of the synthesized NPs displayed FM behavior. An enhancement in the M-r, M-s, H-c, and n(B) was detected at lower Nd3+ and Ce3+ concentrations (x 0.10). The SQR values at RT were smaller than 0.5, indicating a single domain nature with uniaxial anisotropy in all of the produced ferrites. However, the SQR values were in a range of 0.687-0.769 at 10K, suggesting a multi-magnetic domain at low temperatures. This study also examined the impact of Nd3+- and Ce3+-doped cobalt ferrite nanoparticles on human colon cancer cells (HCT-116) to examine their anti-cancer properties using MTT and morphometric assays. After 48 h of treatment with an optimal dose of Nd3+ and Ce3+, the doped cobalt ferrite nanoparticles demonstrated significant apoptotic effects by decreasing cancer cell viability in a dose-dependent manner. These results could lead to the use of NPs as a drug-screening/potential therapeutic strategy targeting human colorectal cancer.