Biosynthesis of CuO nanoparticles and synergistic antibacterial activity using mint leaf extract

This study describes the hydrothermal synthesis of cupric oxide nanoparticles (CuO NPs) using Mint extract agent. A mixture of 0.1 M copper nitrate and a mint extract was hydrothermally treated at a temperature of 180 °C for two hours. Meanwhile, the Mint leaf extract had reduced the copper ions of the nanoparticles after five minutes, resulting in dark-green precipitation. The structural and optical properties of the nanoparticles were studied using X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), and UV-Vis spectroscopy. The nanoparticles showed a simple cubic structure with a crystallite size range of 22 nm ‒ 25 nm. According to the UV-Vis spectrum, an absorption peak was observed at 346 nm. The antibacterial activity was checked against Escherichia coli (E-coli) and Bacillus subtilis (B-subtilis) cultures by which the inhibition zones were found to be 35 mm and 38 mm, respectively. It is concluded that the CuO NPs have a good ability to resist microbes.