Silver speciation and release in commercial antimicrobial textiles as influenced by washing.

The use of nanoscale Ag in textiles is one the most often mentioned uses of nano-Ag. It has previously been shown that significant amounts of the Ag in the textiles are released upon washing. However, the form of Ag present in the textiles remains largely unknown as product labelling is insufficient. The aim of this study was therefore to investigate the solid phase speciation of Ag in original and washed silver textiles using XANES. The original Ag speciation in the textiles was found to vary greatly between different materials with Ag(0), AgCl, Ag2S, Ag-phosphate, ionic Ag and other species identified. Furthermore, within the same textile a number of different species were found to coexist. This is likely due to a combination of factors such as the synthesis processes at industrial scale and the possible reaction of Ag with atmospheric gases. Washing with two different detergents resulted in marked changes in Ag-speciation. For some textiles the two detergents induced similar transformation, in other textiles they resulted in very different Ag species. This study demonstrates that in functional Ag textiles a variety of different Ag species coexist before and after washing. These results have important implications for the risk assessment of Ag textiles because they show that the metallic Ag is only one of the many silver species that need to be considered.

Potential exposure of German consumers to engineered nanoparticles in cosmetics and personal care products.

The rapid increase in the number of consumer products containing engineered nanoparticles (ENP) raises concerns about an appropriate risk assessment of these products. Along with toxicological data, exposure estimates are essential for assessing risk. Currently, cosmetics and personal care products (C&PCP) represent the largest ENP-containing consumer product class on the market. We analyzed factors influencing the likelihood that ENP-containing products are available to consumers. We modelled potential external exposure of German consumers, assuming a maximum possible case where only ENP-containing products are used. The distribution of exposure levels within the population due to different behavior patterns was included by using data from an extensive database on consumer behavior. Exposure levels were found to vary significantly between products and between consumers showing different behavior patterns. The assessment scheme developed here represents a basis for refined exposure modelling as soon as more specific information about ENPs in C&PCP becomes available.

Imaging and characterization of engineered nanoparticles in sunscreens by electron microscopy, under wet and dry conditions.

There is increasing concern over the risks of nanoparticles to humans and the environment, but little is known about the properties of the nanoparticulate mineral filters, such as titanium dioxide and zinc oxide, in sunscreens. There is an urgent need to develop methods for characterizing nanoparticles in (NPs) such products to provide data for human and environmental risk assessments. This study explored three methods (transmission electron microscopy [TEM], conventional scanning electron microscopy [SEM], and wet-scanning electron microscopy [WetSEM]) for characterizing NPs in sunscreens. Our results showed that these products contained titanium dioxide and zinc oxide particles in the nanometer range; thus, it is likely that consumers and the environment are exposed to engineered NPs through the use of these products. Further, we found that the combination of all three microscopy methods provided the most comprehensive information on size-related properties, which are crucial parameters for risk assessment of NPs in wet matrices.

Target-driven selection in a dynamic nitrone library.

Nitrones undergo dynamic exchange in chloroform at room temperature through two mechanisms-hydrolysis and recombination or hydroxylamine addition/elimination; this dynamic exchange is harnessed to select a nitrone-based bis(amidopyridine) receptor for diacids from a group of four nitrones through its binding to a glutaric acid-based target.