Nano toxicology is the study of the toxicity of nanomaterials. Because of quantum size effects and large surface area to volume ratio, nanomaterial’s have unique properties compared with their larger counterparts that affect their toxicity. Of the possible hazards, inhalation exposure appears to present the most concern, with animal studies showing pulmonary effects such as inflammation, fibrosis, and carcinogenicity for some nanomaterials. Skin contact and ingestion exposure are also a concern. Properties that affect toxicity Size is a vital factor in deciding the possible poisonousness of a particle. However it's anything but the lone significant factor. Different properties of nanomaterials that impact poisonousness include: compound organization, shape, surface design, surface charge, collection and solubility, and the presence or nonattendance of utilitarian gatherings of different synthetics. The huge number of factors affecting poisonousness implies that it is hard to make speculations regarding wellbeing hazards related with openness to nanomaterials – each new nanomaterial should be surveyed exclusively and all material properties should be considered. Mechanisms of toxicity Oxidative stress For some types of particles, the smaller they are, the greater their surface area to volume ratio and the higher their chemical reactivity and biological activity. The greater chemical reactivity of nanomaterials can result in increased production of reactive oxygen species (ROS), including free radicals. ROS production has been found in a diverse range of nanomaterials including carbon fullerenes, carbon nanotubes and nanoparticle metal oxides. ROS and free radical production is one of the primary mechanisms of nanoparticle toxicity; it may result in oxidative stress, inflammation, and consequent damage to proteins, membranes and DNA. Cytotoxicity A primary marker for the damaging effects of NPs has been cell viability as determined by state and exposed surface area of the cell membrane. Cells exposed to metallic NPs have, in the case of copper oxide, had up to 60% of their cells rendered unviable. When diluted, the positively charged metal ions often experience an electrostatic attraction to the cell membrane of nearby cells, covering the membrane and preventing it from permeating the necessary fuels and wastes. With less exposed membrane for transportation and communication, the cells are often rendered inactive. NPs have been found to induce apoptosis in certain cells primarily due to the mitochondrial damage and oxidative stress brought on by the foreign NPs electrostatic reactions. Genotoxicity Metal and metal oxide NPs such as silver, zinc, copper oxide, and cobalt oxide have also been found to cause DNA damage. The damage done to the DNA will often result in mutated cells and colonies as found with the HPRT gene test. Submit manuscript at www.longdom.org/submissions/drug-metabolism-toxicology.html or send as an e-mail attachment to the Editorial Office at drugmetabol@eclinjournals.com Regards Lisa D Managing editor Journal of Drug Metabolism & Toxicology