Effect of shape and sulfidation on the toxicity of silver nanoparticles
Wednesday, November 13, 2013
Danielle E. Gorka
Department of Chemistry
Abstract: Silver nanoparticles (AgNPs) are being increasingly used for their antibacterial properties, though little focus has been placed on shape-dependent toxicity. Additionally, chemical changes can occur after entrance into wastewater, where particles often become sulfidized. The aim of this work was to examine the transformations of several shapes of AgNPs through sulfidation and the resulting toxicity to Lolium multiflorum, Danio rerio, and Caenorhabditis elegans. Quasi-spheres, wires, and cubes were synthesized and partial sulfidized. L. multiflorum seeds were exposed to the sulfidized and unsulfidized AgNPs for five days. Plants exposed to unsulfidized particles displayed toxicity in decreased root and shoot length, as well as the absence of root hair. The order of toxicity was semi-spherical AgNPs > silver ions > nanowires ≈ nanocubes > control. Plants exposed to unsulfidized NPs showed the greatest toxicity while plants exposed to sulfidized NPs showed little to no toxicity compared to controls. Toxicity to Danio and C. elegans will also be discussed.