Green Synthesis of Copper Oxide Nanoparticles Using Leaf Extract of Justicia Schimperiana and their Antibacterial Activity

Abstract A fast, efficient, simple and environmentally-friendly, green synthesis method was employed for the synthesis of copper oxide nanoparticles (CuONPs) using easily available, low-cost and non-toxic Justicia Schimperiana plant leaf extract (JSPLE) from Ethiopia. Ultraviolet-Visible (UV-Vis) spectrophotometer, X-ray Diffraction (XRD) technique and Fourier-Transform Infrared (FTIR) Spectroscopy were used to characterize the synthesized CuONPs. The UV-Vis confirmed the formation of CuONPs and the maximum absorbance for the synthesized CuONPs in solution at 212 nm. The different parameters like penta hydrated copper sulphate concentration, volume of leaf extract, temperature, pH and time were optimized spectrophotometrically. The FTIR analysis confirmed the existence of various functional groups responsible for reducing and stabilizing during the biosynthesis process. The XRD result confirmed that the synthesized CuONPs were crystalline in nature with the monoclinic structure and the average crystallite sizes of the particles were 21.8 nm. The synthesized CuONPs showed antimicrobial (gram-negative bacteria (Salmonella typhimurium,Escherichia coli and Klebsiella pneumoniae) and grampositive bacteria (Staphylococcus aureus)) activity. It has been noted that the green synthesized CuONPs showed efficient antibacterial activity against gram-negative (salmonella typhimurium) bacteria with maximum ZOI of 18.6 mm with respect to the highest concentration (150 μg/mL). The developed method for the CuONPs synthesis using JSPLE is an eco-friendly and convenient method. In the near future, the synthesized CuONPs could be used in the fields of biomedicine, biosensor, water treatment and nanotechnology.