Biosynthesis of Copper Oxide Nanoparticles and Evaluation of Their Antimicrobial Properties

Abstract

Objective: This research was carried out to synthesize and characterize copper oxide nanoparticles (CuONPs) using Vernonia amygdalina leaf extract and investigate the in vitro antimicrobial properties using clinical microbial isolates. Methods: The CuONPs were synthesized by heating a mixture of copper sulfate pentahydrate and V. amygdalina aqueous extract. The CuONPs were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and particle size analysis. Phytochemical analysis of V. amygdalina was carried out to determine the bio-molecules that served as a reducing agent during the synthesis of CuONPs. The antimicrobial activities of CuONPs and V. amygdalina were evaluated by the agar disc diffusion method against Staphylococcus aureus, Escherichia coli, and Candida albicans. Ampicillin and fluconazole were used as reference antibacterial and antifungal agents, respectively. Results: The nanoparticles were in the nanometer dimension and exhibited significant antimicrobial activity (P<0.05) against the tested microbes. However, the standard antibacterial drug, ampicillin, showed higher antibacterial activity against S. aureus and E. coli with the inhibition zone diameter of (IZD) of 13.10±0.38 mm and 11.80±0.12 mm, respectively. Fluconazole had no antifungal activity against C. albicans while V. amygdalina demonstrated good antibacterial activity against S. aureus and E. coli but lacked antifungal activity against C. albicans. However, the combination of CuONPs and plant extract exhibited significant antifungal activity with an IZD of 10.37±0.72 mm. Conclusion: An eco-friendly, simple, reproducible, and economical CuONPs have been synthesized using V. amygdalina leaf extract. The findings indicate that CuONPs could be used as an antimicrobial agent.