Structural properties and bacterial inhibition capabilities of Mg0.91Cu0.09O nanoparticles

Copper-doped magnesium oxide (Mg₀.₉₁Cu₀.₀₉O) nanoparticles were synthesized via the sol-gel method and evaluated for their structural, optical, and antibacterial properties. Structural characterization using X-ray diffraction (XRD) confirmed a cubic MgO phase with a crystallite size of 18 nm. Fourier transform infrared (FTIR) analysis revealed characteristic Mg–O and Cu–O vibrational bands, confirming successful doping. Optical properties analyzed via UV-Vis spectroscopy indicated a bandgap energy (Eg) of 2.18 eV, reflecting potential applicability in optoelectronics and photocatalysis. Antibacterial efficacy was tested against Staphylococcus aureus using the agar diffusion method, with a zone of inhibition (ZOI) of 35 mm observed, demonstrating superior antimicrobial performance. The synthesis involved the use of magnesium nitrate and copper nitrate precursors, with citric acid as a chelating agent, followed by calcination at 500 °C. Structural and antibacterial improvements were attributed to the synergistic effects of copper doping, which enhanced reactive oxygen species (ROS) generation and surface interactions with bacterial membranes. These results highlight Mg₀.₉₁Cu₀.₀₉O nanoparticles as promising candidates for antimicrobial coatings and environmental applications. Future research will explore the scalability of synthesis and the effects of copper doping on other bacterial strains.