Are there any neurological effects and risks from nanoparticles to expect ? Translocation of nanoparticles from the

Abstract

There are certain concerns regarding the safety for the environment and human health from the use of engineered na- noparticles (ENPs), which leads to un- intended exposures, in contrast to the use of ENPs for medical purposes. An- imal experiments have shown that inves- tigated ENPs (metallic nanoparticles, quantum dots, carbon nanotubes) can translocate to the brain from different entry points (skin, blood, respiratory pathways). After inhalation or instillation into parts of the respiratory tract a very small fraction of the inhaled or instilled ENPs reaches the blood and subsequent- ly secondary organs, including the cen- tral nerve system, at a low translocation rate. Experimental in vivo and in vitro studies have shown that several types of ENPs can have various biological effects in the nervous system. However, the rel- evance of these data for risk assessment is far from clear. It is, however, unlike- ly that acute high dose exposures would occur. The risk from such exposures to damage the central nerve system is thus probably even lower. This dossier focus- es on the unintended human exposure of ENPs. In particular, possible effects on the functions or processes in the brain are discussed and an attempt to assess the risks is performed. However, the present state of knowledge is unsatis- factory for a proper risk assessment in this area.