A Review of Toxicity of Some Conventional Nanomaterials

Increased production and use of nanomaterials has led to an ever growing exposure of living organisms tothese substances. Limited knowledge about possible toxicity of nanomaterials and their potential to harmliving creatures is becoming a serious concern. To address this problem, there is a need for development ofdiagnostic methods enabling effective determination of potential toxicity of nanomaterials. On the other hand,developing appropriate test methods is contingent on identifying cellular mechanism underlying toxicity ofnanomaterials. This study reviews toxicity of some of the most widely used nanomaterials. According tothe literature, Iron oxide nanoparticles can augment rate of cell death through oxidative stress and lipidperoxidation. Exposure to zinc oxide, gold and silver nanoparticles can result in cell death via mitochondrialdysfunction, expression of abnormal protein in cells, and altering the patterns of gene expression, respectively.Likewise, carbon nanotubes can lead to an increased rate of cell death through the reduction of membranefluidity, thereby destroying cell membrane. Our literature review identified a lower toxic effect for nanotubesas compared with other nano-structures. Regarding the evident high toxicity of nanomaterials, caution mustbe exercised in irregular production and use of these substances in the industry. In addition, from the healthand environmental standpoints, carbon nanotubes are the preferable nano-structures for development ofnanotechnologies regarding their lower toxicity in comparison with other nanomaterials.