Electrospun Cu-Co ferrite nanofibers: synthesis, structure, optical and magnetic properties, and anti-cancer activity.

In this study, we investigated Cu-Co ferrite nanofibers (NFs) that were synthesized for the first time employing the electrospinning technique. The structure, phase purity and crystallite size of all the prepared NFs were revealed by powder X-ray diffraction (PXRD) analysis. The NFs crystallized in the Fd 3̄ m (no. 227) space group and the cation distribution arrangement over distinct sites in their structure was analyzed. Scanning electron microscopy (SEM) together with energy-dispersive X-ray (EDX) spectroscopy analysis showed the microstructure of the NFs and verified their expected chemical compositions. High-resolution transmission electron microscopy (TEM) images confirmed the fibrous nature and the construction of the NFs. The band gap energies derived from the UV-vis reflectance spectra showed a blue shift with an increase in the amount of Cu in the sample from 1.42 eV to 1.86 eV. Magnetization ( M ) as a function of magnetic field ( H ) measurements performed at ambient and low temperatures showed the ferrimagnetic behavior of all the NFs. The magnetic parameters including coercivity ( H c ), saturation magnetization ( M s ), remanent magnetization ( M r ), and squareness ratio were determined from the recorded magnetization curves. At 300 K, M s was reduced from 78.8 to 42.4 emu g -1 , M r reduced from 22.8 to 7.6 emu g -1 and the Bohr magneton reduced from 3.3 to 1.8 μ B with an increase in the content of Cu in the samples. The same trend was observed at 10 K, where M s was reduced from 93.7 to 50.9 emu g -1 , M r reduced from 60.9 to 35.9 emu g -1 and the Bohr magneton reduced from 3.94 to 2.16 μ B . Alternatively, H c has the highest values for x = 0 (850 Oe at 300 K and 5220 Oe at 10 K) and x = 0.6 (800 Oe at 300 K and 5400 Oe at 10 K). The anti-cancer activity of the NFs was evaluated using the MTT cell viability assay, showing a reduction in the viability of both HCT-116 and HeLa cancer cells compared to non-cancerous HEK-293 cells after treatment with the NFs. Apoptotic activity was examined by DAPI staining, where treatment with the NFs induced chromatin condensation and nuclear disintegration in HCT-116 cells.