Ultrafine particles emerge from thermal processes like welding and combustion. They often form larger agglomerates and aggregates that are composed of ultrafine primary particles. Engineered nanoparticles smaller than 100 nm also tend to aggregate and agglomerate. It is not clear to what extent these agglomerates and aggregates resolve into primary particles after inhalation. The size of particles is discussed as a trigger of toxicity, so there is a need to clarify a possible process of deagglomeration and desaggregation within the lung. Furthermore other physico-chemical parameters are discussed to influence toxicity. In appropriate testing systems (in vivo, in vitro) it is intended to elucidate agglomeration and aggregation of nanomaterials in a biological environment. In addition toxicity and transfer of nanoparticles is investigated.
Unit 4.3 "Toxicology"