Aggregation behaviour of carbon nanotubes in aqueous and physiological media and its influence on toxicity

Extensive use of carbon nanotubes (CNTs) in industry and in the consumer market including drug delivery will increase the likelihood of human exposure and the contamination of the ecosystems. The aggregation state of CNTs has a strong influence on their fate and transport in the environment, as well as their bioavailability. Studies on their colloidal behaviour suggest that they can be relatively stable in aqueous and biological medium, and the presence of surfactants and macromolecules may enhance their dispersibility and persistence. This paper is a review of the aggregation behaviour of CNTs as well as their functional analogues, and the possible role of the dispersal state on toxicity.