[Risk of nanoparticles?]

Nanotechnology is an "emerging industry" and becomes more widely used. As a result human exposure to nanoparticles is inevitable. Exposure to nanoparticles can affect the upper aerodigestive tract, before particles reach lung, stomach and intestine. The effects of this passage depend on particle size, particle concentration, the kind of the particle and the duration of contact. Only few in-vitro-investigations about effects of the exposition of nanoparticles on the mucous cells of oral cavity, nose and nasal sinuses exist. In-vitro-analysis with cells of nasal mucous membrane exposed to nanoparticles showed a release of mediators involved in inflammation and allergy development. Cytotoxic and genotoxic effects could be found for several nanoparticles (e.g. carbon nanotubes) in vitro. Due to different size, structure, chemical and physical properties nanoparticles can not be summarized in a homogenous group; quite the contrary risk evaluation of nanoparticles must be carried out case-related. Today toxicological risks can not be evaluated sufficiently. Biological interactions and tissue permeability of manufactured nanoparticles is a major issue for further investigations. In this report the use and health effects of nanoparticles are overviewed.