Structural, optical, and potential broad-spectrum antibacterial properties of CuO-Ag nanoparticles biosynthesized using the extract of Diospyros discolor Willd

Abstract

The development of new material properties for antimicrobial agents to address the problem of antibiotic resistance is currently being explored. Silver and copper exhibit oligodynamic properties, which inhibit the growth of microorganisms. These properties are stronger at the nanoscale than the macroscale, especially for bimetallic nanoparticles (NPs). In this study, we synthesized bimetallic CuO and Ag NPs using Diospyros discolor Willd. (Velvet apple) leaf extract with three different ratios of Cu and Ag precursors: 1:0.01, 1:0.1, and 1:1 (v/v). In addition, the optical properties of these NPs were characterised using UV-Vis spectrophotometer, which showed the typical absorbance peak in the range of 300–400 nm. The size and shape of the CuO and Ag nanoparticles were analysed using a scanning electron microscope (SEM) and transmission electron microscope (TEM) images. The SEM and TEM images showed leaf-shaped CuO nanoplates and spherical AgNPs. Furthermore, the crystalline properties were analysed using x-ray diffraction (XRD). This study produced CuO-Ag nanoclusters with a particular morphology, size, and composition. The antibacterial assay showed potential broad-spectrum activity for Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) as well as Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa).