Published online by Cambridge University Press: 31 January 2011
We investigated the interactions of water soluble single-walled carbon nanotubes (SWNT) with unicellular organisms, in particular a ciliated protozoan (Tetrahymena thermophila) and a bacteria (Escherichia coli), which are common constituents of natural fresh water. The ciliates could effectively incorporate SWNT into natural organic matter (NOM), and therefore into normal ecological processes. Further, SWNT induced the ciliates to egest viable bacteria in membrane-enclosed vesicles. The egested bacteria aggregates had escaped digestion by the protozoan and were able to proliferate and resist antibiotic/disinfectant treatments, which may have important implications to public health. This work highlights the importance of studies on nanoparticle ecotoxicology.