Along with the exuberant development of nanotechnology, a large number of nanoparticles (NPs) are successfully applied in biomedicine, clinics, cosmetics and industry in general. While the inclusion of nanomaterials in different products can enhance their performances, on the other hand, there is growing evidence that the small particle size may also induce undesired side-effects. The reduced size at nano-scale increases in fact the number of surface atoms/molecules and their surface area exponentially, leading to complex biophysicochemical interactions when exposed to physiological environments. Consequently, despite some unique advantages of nanoformulations, there exist potentially worrying toxic effects, particularly those related to metal and metal-containing NPs. The key to understanding the toxicity of NPs is that their minute size allows them to penetrate the basic biological structures, disrupting their normal functions. Examples of toxic effects include tissue inflammation and altered cellular redox balance with increased production of reactive oxygen species (ROS), causing abnormal function, cell damage and death. Animal and human studies show that inhaled NPs are less efficiently removed than larger particles by the macrophage clearance mechanisms in the lung, causing pulmonary damage, and that NPs can translocate through the circulatory, lymphatic, and nervous systems to many tissues and organs, including the brain. Thus, to ensure the safe development of NPs containing products, scientific knowledge on potential hazards posed by different NPs needs to be deepened hand-in hand with the progress in nanotechnological industry. Reaching this ultimate goal will enable us to avoid, at least, synthesizing toxic engineered nanomaterials for commercial use. Moreover understanding the mechanism of interactions of NPs with cells and their consequences is the first defence in hazard prevention also with reference to the accidentally produced NPs due to human activities or derived from natural causes [1-4]. References  M.A. Zoroddu, S. Medici, A. Ledda, V.M. Nurchi, J.I. Lachowicz, M. Peana, Toxicity of nanoparticles, Curr Med Chem 21(33) (2014) 3837-53.  M.A. Zoroddu, S. Medici, M. Peana, V.M. Nurchi, J.I. Lachowicz, M. Costa, Tungsten or Wolfram: Friend or Foe?, Curr Med Chem 24 (2017) 1-10.  F. Laulicht, J. Brocato, L. Cartularo, J. Vaughan, F. Wu, T. Kluz, H. Sun, B.A. Oksuz, S. Shen, M. Peana, S. Medici, M.A. Zoroddu, M. Costa, Tungsten-induced carcinogenesis in human bronchial epithelial cells, Toxicol Appl Pharmacol 288(1) (2015) 33-9.  J.I. Lachowicz, V.M. Nurchi, G. Crisponi, M.A. Zoroddu, M. Peana, S. Medici, Antimicrobial Nanoarchitectonics. 1st Edition, From Synthesis to Applications. Chapter 18. Toxicity Of Nanoparticles: Etiology And Mechanisms. Elsevier 2017. ISBN: 9780323527330
Toxicity of metal nanoparticles / Peana, Massimiliano Francesco; Medici, Serenella; Zoroddu, Maria Antonietta. - (2017), pp. 70-70. ((Intervento presentato al convegno 1st Workshop “NanoBioMed Sardinia 2017" tenutosi a Alghero nel 24-27 giugno 2017.