Prof. Joel N. Meyer will give a Seminar entitled “Mechanisms of uptake and toxicity of silver nanoparticles in Caenorhabditis elegans“, today, December 15, at 12 pm at ICMAB Conference Room Carles Miravitlles.
Prof. Joel N. Meyer is Associate Professor and Director of Graduate Studies at Nicholas School of the Environment and Center for the Environmental Implications of Nanotechnology (CEINT), at Duke University, NC, USA.
Engineered nanomaterials offer great opportunities due to their novel properties. However, there is concern that these novel properties may also result in deleterious effects on human and ecological health that are difficult to predict based only on an understanding of the chemical makeup. We tested a number of nanoparticles (NPs) for toxicity in the nematode model Caenorhabditis elegans, and found that certain silver NPs (AgNPs) were the most toxic of the NPs that we had tested. We therefore extended our studies to characterize environmental factors that might alter AgNP toxicity, as well as the uptake and mechanism of toxicity of AgNPs in C. elegans.
Because much AgNP waste is expected to end up in aquatic ecosystems, we tested the influence of environmental variables on toxicity. We found that higher ionic strength, the presence of natural organic matter, and sulfidation of the AgNPs (expected to occur in many environments after AgNP release) all significantly reduced Ag NP toxicity. Using physicochemical, genetic, and pharmacological rescue approaches, we found that the most toxic AgNPs -generally, the smallest- caused their effects largely via dissolution. Some AgNPs (typically less soluble due to size or coating) also caused toxicity via generation of reactive oxygen species, an effect specific to nanoparticulate silver. This effect was masked by the toxicity of silver ions except when dissolution was very limited. The toxicity of the tested AgNPs was almost never greater than would result from complete dissolution of the same mass of silver. We also found that endocytosis was an important mechanism for AgNP uptake. However, the specific mechanisms by which AgNPs or released silver ion cause toxicity remain unclear. Because AgNPs are used to kill microbes, and mitochondria are endosymbiotic descendants of bacteria, current studies are focused on testing the possibility that AgNPs cause some of their toxicity via disruption of mitochondrial function.
If you would like to arrange a meeting with Prof. Joel N. Meyer please contact: Dr. Anna Laromaine (firstname.lastname@example.org).