Synthesis and characterization of NiO nanoparticles by chemical as well as green routes and their comparisons with respect to cytotoxic effect and toxicity studies in microbial and MCF-7 cancer cell models

This contribution reports on the synthesis and also compares the main physical properties of nickel oxide nanoparticles (NiO NPs) synthesized by a completely green process using Gymnema sylvestere plant extract and sodium hydroxide as an effective reducing agent for co-precipitation method. The synthesized nanoparticles were characterized by XRD, HRTEM, EDS, FTIR, UV–visible, XPS, EPR and zeta potential analysis methods. Further the synthesized NiO NPs were evaluated the in vitro toxicity studies using microbial and MCF-7 cancer cell line models. Further cytotoxicity studies and acridine orange and ethidium bromide staining confirmed that green synthesized NiO NPs possess low toxicity compared with chemically synthesized NiO NPs.