Sorption of cysteine to silver nanoparticles: Implications for aggregation, dissolution and silver speciation
Monday, October 3, 2011
Andreas Gondikas is a Ph.D. student in the Department of Civil and Environmental Engineering.
Abstract: The wide use of metallic silver nanoparticles in commercial products has recently gained much attention due to the potential for toxicity resulting from unintended releases to the environment. The persistence of silver nanoparticles after their release will depend on key transformation processes in aquatic systems that include aggregation, dissolution, and surface modifications by metal-complexing ligands. These processes work in concert to influence the lifetime of the nanoparticles in the environment and bioavailability of silver to exposed organisms. Here, we studied the surface chemistry, aggregation, and dissolution of silver nanoparticles after exposure to cysteine, a ligand that is representative of thiols that can dominate silver speciation in environmental aquatic systems. We compared metallic silver nanomaterials that were synthesized with two different coatings (citrate or polyvinylpirrolidone) and demonstrated that surface modifications are expected to drastically influence the long term reactivity of the materials in the aquatic environment and the bioavailability to exposed organisms.