A micro-sized model for the in vivo study of nanoparticle toxicity: What has Caenorhabditis elegans taught us?

Environmental context The ability of the soil nematode Caenorhabditis elegans to withstand a wide range of environmental conditions makes it an idea model for studying the bioavailability and effects of engineered nanomaterials. We critically review what has been learned about the environmental fate of engineered nanoparticles, their effects and their mechanisms of toxicity using this model organism. Future systematic manipulation of nanoparticle properties and environmental variables should elucidate how their interaction influences toxicity and increase the predictive power of nanomaterial toxicity studies. Abstract Recent years have seen a rapid increase in studies of nanoparticle toxicity. These are intended both to reduce the chances of unexpected toxicity to humans or ecosystems, and to inform a predictive framework that would improve the ability to design nanoparticles that are less likely to cause toxicity. Nanotoxicology research has been carried out using a wide range of model systems, including microbes, cells in culture, invertebrates, vertebrates, plants and complex assemblages of species in microcosms and mesocosms. These systems offer different strengths and have also resulted in somewhat different conclusions regarding nanoparticle bioavailability and toxicity. We review the advantages offered by the model organism Caenorhabditis elegans, summarise what has been learned about uptake, distribution and effects of nanoparticles in this organism and compare and contrast these results with those obtained in other organisms, such as daphnids, earthworms, fish and mammalian models.