A Review on Green Synthesis, Cytotoxicity Mechanism and Antibacterial Activity of Zno-NPs

Recently, the development of eco-friendly methods for the synthesis of nanoparticles is an important key to nanotechnology. The use
of green techniques using plants for the synthesis of nanoparticles is a replacement for chemical and physical techniques, because they
are hazardous. Therefore, in this paper, we refer to green synthesis method using plant extracts and cytotoxicity and antibacterial
mechanisms. Zinc oxide nanoparticles (ZnO-NPs) have been considered with regard to unique properties such as biocompatibility,
selective cytotoxicity, anti-cancer and antibacterial activity. These nanoparticles are dissolved in the medium or in the cell and zinc
ions are released, these zinc ions result in zinc-mediated protein activity disequilibrium and oxidative stress through reactive oxygen
species, which may have a potential mechanism of action cytotoxicity of nanoparticles. Given the selective cytotoxic effects of ZnO-
NPs due to the presence of more ROS in cancer cells, these nanoparticles can selectively target cancer cells and can be used as an
anticancer agent. On the other hand, ZnO-NPs have significant antibacterial properties. Antimicrobial mechanism of ZnO-NPs may
take place through the interaction of nanoparticles with bacterial cell surface and the production of reactive oxygen species (ROS) and
release of zinc ions. ROS and free ions are important factors for several mechanisms, including increased membrane permeability, cell
wall damage. These will weaken the mitochondria and cause oxidative stress and ultimately inhibit cell growth and cell death. Due to
the selective toxicity effect against cancer cells, it can be used as a useful agent for the treatment of cancer and an alternative to
antibiotics