Green synthesis of ZnO nano-crystals using Chenopodium album L. Leaf extract, their characterizations and antibacterial activities

Abstract

We present an effective, simple and eco-friendly method for the green synthesis of ZnO nano-crystals. An aqueous extract of Chenopodium album leaf was used as a biological reducing agent for the fabrication of ZnO nano-crystals from the zinc sulphate heptahydrate. The as-prepared and annealed powder samples were characterized using advanced techniques. The results confirmed the presence of ZnO crystals with a broad size distribution, whose crystallinity was noticed to improve substantially after the annealing. Further, in antibacterial activity test of ZnO nano-crystals performed on Escherichia coli and Staphylococcus aureus microorganisms, inhibitory effect was found to increase with concentration. Compared to Gram-positive bacteria, ZnO nano-crystals showed more resistance to Gram-negative bacteria. This green synthesis route of ZnO nano-crystals is novel and aims to reduce the use of toxic chemicals in fabricating the nanoparticles of functional oxides, which have a wide range of potential applications in general and biomedical science, in particular.