ABSTRACT
Despite increasing application of silver nanoparticles (NPs) in industry and consumer products, there is still little known about their potential toxicity, particularly to organisms in aquatic environments. To investigate the fate and effects of silver NPs in fish, rainbow trout (Oncorhynchus mykiss) were exposed via the water to commercial silver particles of three nominal sizes: 10 nm (N(10)), 35 nm (N(35)), and 600-1600 nm (N(Bulk)), and to silver nitrate for 10 days. Uptake into the gills, liver, and kidneys was quantified by inductively coupled plasma-optical emission spectrometry, and levels of lipid peroxidation in gills, liver, and blood were determined by measurements of thiobarbituric acid reactive substances. Expression of a suite of genes, namely cyp1a2, cyp3a45, hsp70a, gpx, and g6pd, known to be involved in a range of toxicological response to xenobiotics was analyzed in the gills and liver using real-time PCR. Uptake of silver particles from the water into the tissues of exposed fish was low but nevertheless occurred for current estimated environmental exposures. Of the silver particles tested, N(10) were found to be the most highly concentrated within gill tissues and N(10) and N(Bulk) were the most highly concentrated in liver. There were no effects on lipid peroxidation in any of the tissues analyzed for any of the silver particles tested, and this is likely due to the low uptake rates. However, exposure to N(10) particles was found to induce expression of cyp1a2 in the gills, suggesting a possible increase in oxidative metabolism in this tissue.
Subject(s)
Life Cycle Stages/drug effects , Metal Nanoparticles/toxicity , Oncorhynchus mykiss/physiology , Silver Compounds/toxicity , Water Pollutants, Chemical/toxicity , Animals , Cytochrome P-450 CYP1A2/biosynthesis , Enzyme Induction , Female , Gene Expression/drug effects , Gills/drug effects , Gills/metabolism , Kidney/drug effects , Kidney/metabolism , Lipid Peroxidation , Liver/drug effects , Liver/metabolism , Oxidoreductases/genetics , Oxidoreductases/metabolism , Particle Size , Silver Compounds/pharmacokinetics , Thiobarbituric Acid Reactive Substances/metabolism , Water Pollutants, Chemical/pharmacokineticsABSTRACT
Density functional calculations are presented on the structure and magnetic parameters of the perfluorinated ethyl and n-propyl radicals and compared with the non-fluorinated analogs. It is found that fluorine substitution leads not only to nonplanarity at the radical center but to delocalization of spin density onto the Falpha atoms and to spin polarization effects that both lead to pronounced anomalies in the anisotropic contribution to the hyperfine tensor. The nonplanar radicals do not obey the traditional McConnell relations. They serve as model systems for similar species that are observed in perfluorinated polymers.
