Uptake and toxicity of Silver nanoparticles and their interactions with environmental factors
Monday, March 12, 2012
Xinyu Yang is a doctoral student in Nicholas School of the Environment.
Abstract: The rapidly increasing application of silver nanoparticles (Ag NPs) in consumer products and medical applications has raised both ecological and human health concerns. Using Caenorhabditis elegans, we have tested a series of differentially coated Ag NPs and found a linear correlation between Ag NP toxicity and oxidative dissolution, but no correlation between size and toxicity. Oxidative dissolution was critical to the toxicity of most Ag NPs, highlighting a critical role for dissolved silver in the toxicity of all tested Ag NPs.
We explored the impact of both Natural Organic Matter (NOM) and sufide on Ag NP toxicity, and found that both factors are reducing toxicity. To explore the NOM effect in more depth, we carried out a series of uptake examinations using the Cytoviva Hyperspectra system, which indicates alterations of uptake due to the presence of NOM. We also used a genetic approach, which involved 3 receptor-mediated endocytosis-deficient mutants (rme-1, rme-8 and rme-6), to address the hypothesis that endocytosis is involved in Ag NP uptake and associated toxicity. In addition, we studied the impact of temperature in Ag NPs, showing increased toxicity at higher temperature.
This work is important in further understand the in vivo behavior of Ag NPs, which can facilitate the mechanistic study and ecological risk assessment of Ag NP toxicity.