Synthesis of Copper Oxide Nanoparticles Using Fruit Peel Extract of Actinidia deliciosa (Kiwi) for Antimicrobial Activity

Copper oxide nanoparticles (CuO NPs) were synthesized using Actinidia deliciosa (Kiwi) fruit peel extract via a microwave-assisted green synthesis method. The X-ray diffraction (XRD) analysis confirmed the monoclinic CuO phase, with crystallite sizes calculated at approximately 9 nm. Fourier-transform infrared spectroscopy (FTIR) results revealed characteristic bands for O-H, C-H, C=C, C-OH, and Cu-O functional groups, confirming the presence of bioactive molecules from the kiwi peel extract stabilizing the nanoparticles. Scanning electron microscopy (SEM) revealed spherical and agglomerated particles, while energy dispersive X-ray (EDX) spectroscopy confirmed the elemental composition of copper (36.95%) and oxygen (52.09%). Antibacterial activity was evaluated using the agar well diffusion method against four pathogens: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. Significant zones of inhibition were observed, with inhibition zones ranging from 9.5 to 17.8 mm, demonstrating strong antimicrobial activity. The CuO NPs exhibited concentration-dependent antibacterial effects, with higher concentrations (600 µg/mL) showing maximum inhibition. These results support the potential of kiwi peel-derived CuO NPs as an eco-friendly antimicrobial agent.