Increased use of nanomaterials in drugs and consumer products has led to concerns over adverse effects on humans and ecosystems. Gold nanoparticles even though primarily being explored for use in medicine, can serve as an ideal probe for evaluating particle-specific toxic effects due to their insolubility.
Dr. Olga Tsyusko and collaborators Jason Unrine, Paul Bertsch, Daniel Starnes and Greg Joice from the department of Plant and Soil Sciences, among others, recently published a paper investigating the mechanisms of gold nanoparticle toxicity in the model nematode, Caenorhabditis elegans, in the journal Environmental Science & Technology.
This study used toxicogenomic and functional genomic tools to identify several possible biological pathways activated as result of exposure to gold nanoparticles as well as the genes associated with mechanisms of toxicity and detoxification. Activation of endocytosis genes suggested that gold nanoparticles are taken up by cells through clathrin-mediated endocytosis. Once inside the cells the gold nanoparticles caused unfolded protein responses (UPR) and activation of the genes associated with the amyloid-like processing pathway. These results indicate that the gold nanoparticles may interfere with proper protein folding or re-folding once inside the cell. Toxicity experiments conducted with mutant strains and RNA interference knock-downs further confirmed involvement of the genes from the endocytosis and UPR pathways. These results are significant because they demonstrate novel nanomaterial-specific mechanisms of toxicity in vivo after relatively low-level exposure. The study raises concerns about the potential toxicity of gold nanoparticles, which are widely thought to be relatively inert.
Tsyusko et al. 2012. Environmental Science & Technology 46: 4115-4124