Biological and Environmental Transformations of Copper-Based Nanomaterials

• DOI: 10.1021/nn403080y
• Publication Date: 2013-09-13T19:08:21Z
• Authors: Zhongying Wang; Annette von dem B...; Pranita K. Kabadi; Agnes B. Kane; Robert H. Hurt
• Keywords: Sulfidation; Copper sulfide; Nanomaterials

Copper-based nanoparticles are an important class of materials with applications as catalysts, conductive inks, and antimicrobial agents. Environmental safety issues particularly for copper-based nanomaterials because their potential large-scale use high redox activity toxicity reported from in vitro studies. Elemental nanocopper oxidizes readily upon atmospheric exposure during storage use, so copper oxides highly relevant phases to consider studies environmental health impacts. Here we show that oxide undergo profound chemical transformations under conditions living systems the natural environment. Copper nanoparticle (CuO-NP) dissolution occurs at lysosomal pH (4-5), but not neutral pure water. Despite near-neutral cell culture medium, CuO-NPs significant media over time scales testing ligand-assisted ion release, which amino acid complexation is contributor. Electron paramagnetic resonance (EPR) spectroscopy shows dissolved association primary redox-active species. also sulfidation by a dissolution-reprecipitation mechanism, new sulfide surfaces act catalysts oxidation. NPs found be much less cytotoxic than CuO-NPs, consistent very low solubility CuS. this CuS, EPR sulfidated CuO continues generate some ROS due release free H2O2 oxidation Fenton-chemistry-based assay. While can serve detoxification process nanosilver other chalcophile metals, our results suggest may fully permanently detoxify biological or compartments contain reactive oxygen