In the context of assessing the potential risks of nanomaterials, a lifecycle approach (covering production, use and disposal of the NM or nano-product) represents a holistic view of their potential impacts. Considering nanomaterial life cycles are determined by application within a product, relevant exposure scenarios and particle aging/transformations are strongly dependent on the life-cycle of nano-enhanced products themselves. For example, nanomaterials embedded in textiles would transform after exposure to oxidants and detergents during washing. We simulated the aging of Ag engineered nanoparticles (ENP) of different sizes and surface chemistries (uncoated, citrate, PEG and fulvic acid) and Ag+ through storage, exposure to oxidants (H2O2 ranging from 0.03% to 3% W/V) and/or to suspension in standard detergent formulations. Transformations over multiple exposures (e.g., aged suspension in detergent and subsequent exposure to oxidants) were also investigated. Observations of transformation from the various treatments included measurement of particle dissolution (Ag+ release, primary particle diameter reduction), characterization of surface transformation(s) and precipitation of �new� Ag NP from Ag+. All particles underwent transformations changing their fundamental starting characteristics. Alongside the systematic work of determining the mechanistic changes of the ENPs described above, ENPs and traditional Ag textile additives (AgCl, AgCl/TiO2 composites and Ag-zeolites) were imbedded in a knitted fabric and washed under laboratory conditions to determine if the mechanistic studies were a good indicator for changes that occur during realistic use. All Ag additives released Ag in the nano-size range, producing various particles including metallic Ag, Ag2S, and AgCl. This work highlights the fact that since Ag ENPs will readily be aged/transformed during a products life cycle, it is prudent to consider how these by-products differ from pristine ENPs. This is especially true when attributing toxicity or safety assessments to materials, which may be best done with the (relevantly) transformed particles rather than the pristine version.

Transformations of silver nanoparticles relevant to product use: Exposure to disinfectants and washing textiles

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.