Neurotoxicity of Nanoparticles

The evidence for the neurotoxicity of nanoparticles is summarized. The sources of such particles and the ways in which they may enter the brain are listed and discussed. These include the olfactory pathway, the respiratory tract, and the possibility of transport across the blood-brain barrier. However, nanoparticles acting systemically can also be neurotoxic without directly entering the brain. The means by which nanoparticles can be injurious to the central nervous system include both their physical characteristics such as their form and size, and their chemical composition. Particles containing transition metals the possibility of valence flux under biological conditions, may promote prooxidant events in the nervous tissues. Futile activation of astroglial immune responses can initiate chronic inflammatory events. The toxicity of airborne particles includes evidence of oxidative damage and heightened inflammation in the brain. The consequences of these changes may include the advancement of several prevalent neurodegenerative disorders such as Alzheimer's and Parkinson's diseases characterized by excess levels of oxidative damage and inflammatory changes. Conclusive detection of such changes in incidence consequent to particulate exposure remains elusive