Biogenic synthesis of magnesium-doped copper oxide nanocomposites using tangerine peel extract: structural, optical, and bioactivity studies

In this work, pristine and magnesium-doped copper oxides (Mg-doped CuO/Cu₂O) nanocomposites (NCs) were synthesized using tangerine peel aqueous extract-based phyto-compounds as facilitating agents for nanoparticle production. The NCs were characterized using Fourier transform infrared, ultraviolet–visible, scanning electron microscope, and X-ray diffraction. Analysis confirms the production of pure composites having flake-like morphology, crystallite sizes less than ca. 54.15 nm (decreased due to doping), and bandgaps of 2.16 and 3.57 eV for undoped and Mg-doped NCs. The antibacterial activity, performed on gram-positive (Staphylococcus aureus) and gram-negative (Klebsiella pneumoniae and Escherichia coli) bacteria using the disk diffusion method in reference to gentamicin, revealed an almost similar moderate effect at all tested concentrations, being just a little more active against gram-positive S. aureus bacteria. Hemolytic results in reference to distilled water, suggesting no or slight lysis of erythrocytes up to 500 μg/mL. However, as the mechanism of bioaction still needs to be fully understood, more investigations in terms of bacteria types and hemolysis conditions may be necessary.