Broad applications of iron oxide nanoparticles require an improved understanding of their potential effects on human health. In the present study, we explored the underlyingmechanismthrough which iron oxide nanoparticles induce toxicity in human breast cancer cells (MCF-7). MTT (3-(4, 5- dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) and lactate dehydrogenase assays were used to examine mechanisms of cytotoxicity. Concentration- and time-dependent cytotoxicity was observed in MCF-7 cells. Iron oxide nanoparticles were found to induce oxidative stress evidenced by the

Toxicity of nanoparticles depends on many factors including size, shape, chemical composition, surface area and surface charge. Silver nanoparticles (AgNPs) are likely to enter the aquatic ecosystems because of their multiple applications and pose a health concern for humans and aquatic species. Therefore, we used a freshwater snail Lymnaea luteola L (L. luteola) to investigate the acute toxicity and genotoxicity of AgNPs in a static-renewal system for 96 h. AgNPs caused molluscicidal activity in L. luteola, with 96- h median lethal concentrations (LC50) (48.10 lg L1).

 Carbon nanotubes (CNTs) are gradually used in various areas including drug delivery, nanomedicine, biosensors, and electronics. The current study aimed to explore the DNA damage and cytotoxicity due to single-walled carbon nanotubes (SWCNTs) on human hepatocarcinoma cells (HepG2). Cellular proliferative assay showed the SWCNTs to exhibit a significant cell death in a dose- and timedependent manner. However, SWCNTs induced significant intracellular reactive oxygen species (ROS) production and elevated lipid peroxidation, catalase, and superoxide dismutase in the HepG2 cells.