Phytogenic Synthesis of Cuprous and Cupric Oxide Nanoparticles Using <i>Black jack</i> Leaf Extract: Antibacterial Effects and Their Computational Docking Insights

<b>Background:</b> Green synthesized nanoparticles (NPs) have gained increasing popularity in recent times due to their broad spectrum of antimicrobial properties. This study aimed to develop a phytofabrication approach for producing cuprous (Cu₂O) and cupric oxide (CuO) NPs using a simple, non-hazardous process and to examine their antimicrobial properties. <b>Methods:</b> The synthesis employed <i>Bidens pilosa</i> plant extract as a natural reducing and stabilizing agent, alongside copper chloride dihydrate as the precursor. The biosynthesized NPs were characterized through various techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectroscopy, ultraviolet–visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). <b>Results:</b> XRD analysis confirmed that the synthesized CuO and Cu₂O NPs exhibited a high degree of crystallinity, with crystal structures corresponding to monoclinic and face-centered cubic systems. SEM images revealed that the NPs displayed distinct spherical and sponge-like morphologies. EDS analysis further validated the purity of the synthesized CuO NPs. The antimicrobial activity of the CuO and Cu₂O NPs was tested against various pathogenic bacterial strains, including <i>Staphylococcus aureus</i>, <i>Pseudomonas aeruginosa</i>, <i>Escherichia coli</i>, and <i>Bacillus cereus</i>, with the minimum inhibitory concentration (MIC) used to gauge their effectiveness. <b>Conclusions:</b> The results showed that the phytosynthesized NPs had promising antibacterial properties, particularly the Cu₂O NPs, which, with a larger crystal size of 68.19 nm, demonstrated significant inhibitory effects across all tested bacterial species. These findings suggest the potential of CuO and Cu₂O NPs as effective antimicrobial agents produced via green synthesis.