This study aims to investigate the effect of magnesium (Mg) doping on the characteristics and antibacterial properties of copper oxide (CuO) nanoparticles (NPs). The Mg-doped CuO NPs were fabricated by the co-precipitation method. NPs were characterized by X-ray Powder Diffraction (XRD), Transmission Electron Microscope (TEM), Energy Dispersive X-ray (EDX) analysis, Fourier Transform Infrared Spectroscopy (FTIR), and Photoluminescence (PL). Broth microdilution, agar-well diffusion, and time-kill assays were employed to assess the antibacterial activity of the NPs. XRD revealed the monoclinic structure of CuO NPs and the successful incorporation of Mg dopant to the Cu1−xMgxO NPs. TEM revealed the spherical shape of the CuO NPs. Mg doping affected the morphology of NPs and decreased their agglomeration. EDX patterns confirmed the high purity of the undoped and Mg-doped CuO NPs. FTIR analysis revealed the shifts in the Cu–O bond induced by the Mg dopant. The position, width, and intensity of the PL bands were affected as a result of Mg doping, which is an indication of vacancies. Both undoped and doped CuO NPs exhibited significant antibacterial capacities. NPs inhibited the growth of Gram-positive and Gram-negative bacteria. These results highlight the potential use of Mg-doped CuO NPs as an antibacterial agent.

Doping in metal oxide systems is being chased by many researchers since it is enhancing their properties. In the present study, Cu1-xMgxO nanoparticles, capped with EDTA were synthesized by the chemical co-precipitation method, with x = 0.000, 0.005, 0.010, 0.015, and 0.020, and further characterized by different techniques. The impact of doping by Mg2+ ions on the structural, optical, and magnetic properties of CuO nanoparticles was investigated and the antibacterial activity of the synthesized nanoparticles was studied by antibiofilm screening. The X-ray Powder Diffraction (XRD) patterns show the formation of a pure CuO phase with a good incorporation of Mg-dopant into the CuO lattice due to the comparable ionic radii of Cu2+ and Mg2+ ions. The Mg-dopant increases the crystallite size from 25 nm (at x = 0.000) to 28.12 nm (at x = 0.020). The Transmission Electron Microscope (TEM) images reveal the effect of Mg-doping on the morphology of CuO nanoparticles by decreasing their agglomeration, resulting in more uniform spherical-shaped nanoparticles. Energy Dispersive X-ray (EDX) and X-ray Photoelectron Spectroscopy (XPS) confirm the purity and the successful development of Mg-doped CuO nanoparticles. The changes in the characteristic vibrational modes of CuO are studied by Raman spectra, upon Mg-doping. Furthermore, the optical properties explored by Ultraviolet-Visible (UV-Vis) spectroscopy reveal a redshift of the absorption peaks of CuO nanoparticles due to the Mg-doping. The energy gap (Eg) is affected by Mg-doping, where its broadening is attributed to the quantum confinement effect in CuO. The magnetic properties were investigated by Vibrating Sample Magnetometer (VSM) at room temperature. Cu1-xMgxO nanoparticles have combined paramagnetic and weak ferromagnetic behaviors. Besides, Cu1-xMgxO nanoparticles exhibited significant antibiofilm effects. These results highlight the potential use of Mg-doped CuO nanoparticles as antibiofilm agents.

The increase in environmental pollution, especially water pollution, has intensified the requirement for new strategies for the treatment of water sources. Furthermore, the improved properties of nano-ferrites permit their usage in wastewater treatment. In this regard, novel Mg0.33Ni0.33Co0.33LaxFe2−xO4 nanoparticles (NPs), where 0.00≤x≤0.08, were synthesized to test their photocatalytic, antibacterial and antibiofilm activities. The structural and optical properties of the prepared NPs were investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), UV-Vis spectroscopy and photoluminescence (PL) analysis. As La content increases, the bandgap energy increases, whereas the particle size decreases. The photocatalytic activity of the prepared NPs is evaluated by the degradation of methylene blue (MB) dye under sunlight irradiation. Superior activity is exhibited by Mg0.33Ni0.33Co0.33La0.01Fe1.99O4 NPs. The influence of catalyst dosage, pH, temperature and addition of graphene (Gr) on the photodegradation reaction was studied. Increasing the pH and temperature improved the rate of the photodegradation reaction. The antibacterial and antibiofilm activities of the NPs were assessed against Escherichia coli, Leclercia adecarboxylata, Staphylococcus aureus and Enterococcus faecium. Mg0.33Ni0.33Co0.33Fe2O4 NPs inhibited bacterial growth. They had bacteriostatic activity on all isolates, with a greater effect on Gram-positive bacteria. All tested nano-ferrites had significant antibiofilm activities against some biofilms.

This study reports the synthesis of Mg0.33Ni0.33Co0.33GdxFe2‐xO4 nanoparticles (NPs) with 0.00≤x≤0.08 by the co‐precipitation method. The structural and optical properties of NPs are investigated. As Gd content increases, the lattice parameter and the bandgap energy increase whereas the particle size decreases. The photocatalytic performance of NPs is evaluated in the degradation of methyl violet (MV) dye under sunlight irradiation. The best activity is exhibited by Mg0.33Ni0.33Co0.33GdxFe2‐xO4 where x=0.04. The rate of the photodegradation reaction is boosted by increasing the pH and temperature. 95.4 % of MV is degraded after 240 min upon the addition of 5 wt. % carbon dot. The NPs are tested against Gram‐positive (Staphylococcus aureus and Enterococcus faecium) and Gram‐negative bacteria (Escherichia coli and Leclercia adecarboxylata) isolated from wastewater. The antibacterial activity was tested by the minimum inhibitory concentration and minimum bactericidal concentration broth microdilution assay, agar well diffusion assay and time‐kill test. The results show that the NPs exhibit inhibitory activity against Gram‐positive bacteria. Furthermore, NPs show bacteriostatic activity after 3 hours of incubation. The antibiofilm activity of the NPs is tested by the inhibition of biofilm formation and the destruction of pre‐formed biofilm assays. The results show an inhibitory activity of the NPs against Gram‐positive biofilms.