Micro-PIXE study of Ag in digestive glands of a nano-Ag fed arthropod ( Porcellio scaber, Isopoda, Crustacea) (original) (raw)
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Marine Environmental Research, 2013
The fast expansion of the global nanotechnology market entails a higher environmental and human exposure to nanomaterials. Silver nanoparticles (AgNP) are used for their antibacterial properties; however, their environmental fate is yet poorly understood. Iceland scallops (Chlamys islandica) were exposed for 12 h to three different silver forms, dissolved Ag(I) (Ag diss ), small (S-NP, B ¼ 10e20 nm) and large AgNP (L-NP, B ¼ 70e80 nm), labeled with 110m Ag, and bioaccumulation kinetics and tissue distribution using in vivo gamma counting and whole-body autoradiography were determined. All Ag forms were readily and rapidly accumulated. Elimination process was also fast and bi-exponential, with mean biological half-life ranging from 1.4 to 4.3 days and from 17 to 50 days for fast and slow compartments, respectively. Most of the radioactivity concentrated in the hepatopancreas. Ag diss and S-NP tissue distributions were similar indicating a rapid dissolution of the latter in the tissues, contrarily to L-NP which appeared to form long lasting aggregates in the digestive system. Estimated steady-state bioconcentration factors (BCF), ranging between 2700 and 3800 ml g À1 for dissolved and particulate silver forms, showed that C. islandica can accumulate significant quantities of Ag in a short time followed by an efficient depuration process.
Nanotoxicology, 2017
Bioavailability and toxicity of maltose-stabilised AgNPs of different sizes (20, 40 and 100 nm) in mussels were compared with bulk and aqueous forms of the metal through a two-tier experimental approach. In the 1 st tier, mussels were exposed for 3 d to a range of concentrations (0.75, 75, 750 µg Ag/l) in the form of Ag20-Mal, Ag40-Mal, Ag100-Mal, bulk Ag and aqueous Ag (as AgNO 3), as well as to the concentrations of maltose used in the formulation of NPs. Mortality, bioaccumulation, tissue and cell distribution and lysosomal responses were investigated. In the 2 nd tier, mussels were exposed for 21 d to Ag20-Mal, Ag100-Mal, bulk Ag and aqueous Ag at the lowest effective concentration selected after Tier 1 (0.75 µg Ag/l), biomarkers and toxicopathic effects were investigated. Aqueous Ag was lethal within 3 d at 75 µg Ag/l; Ag NPs or bulk Ag did not produce significant mortality at 750 µg Ag/l. Ag accumulation was limited and metallothionein gene transcription was not regulated although metal accumulation occurred in digestive, brown and stomach epithelial cells and in gut lumen after exposure to AgNPs and aqueous Ag starting at low concentrations after 1 d. Electrondense particles (<10 nm) in lysosomes and residual bodies after exposure to AgNPs contained Ag and S (X-ray). Intralysosomal metal accumulation and lysosomal membrane destabilisation were enhanced after exposure to all the forms of Ag and more marked after exposure to Ag20-Mal than to larger NPs. 21 d exposure to AgNPs provoked digestive cell loss and loss of digestive gland integrity, resulting in atrophy-necrosis in digestive alveoli and oedema/ hyperplasia in gills (Ag NP), vacuolisation in digestive cells (aqueous Ag) and haemocyte infiltration of connective tissue (all treatments). Intralysosomal metal accumulation, lysosomal responses and toxicopathic effects are enhanced at decreasing sizes and appear to be caused by Ag + ions released from NPs, although the metal was not substantially accumulated.
Environmental Science and Pollution Research, 2012
Although silver nanoparticles (NPs) are increasingly used in various consumer products and produced in industrial scale, information on harmful effects of nanosilver to environmentally relevant organisms is still scarce. This paper studies the adverse effects of silver NPs to two aquatic crustaceans, Daphnia magna and Thamnocephalus platyurus. For that, silver NPs were synthesized where Ag is covalently attached to poly(vinylpyrrolidone) (PVP). In parallel, the toxicity of collargol (protein-coated nanosilver) and AgNO 3 was analyzed. Both types of silver NPs were highly toxic to both crustaceans: the EC50 values in artificial freshwater were 15-17 ppb for D. magna and 20-27 ppb for T. platyurus. The natural water (five different waters with dissolved organic carbon from 5 to 35 mg C/L were studied) mitigated the toxic effect of studied silver compounds up to 8-fold compared with artificial freshwater. The toxicity of silver NPs in all test media was up to 10-fold lower than that of soluble silver salt, AgNO 3. The pattern of the toxic response of both crustacean species to the silver compounds was almost similar in artificial freshwater and in natural waters. The chronic 21-day toxicity of silver NPs to D. magna in natural water was at the part-per-billion level, and adult mortality was more sensitive toxicity test endpoint than the reproduction (the number of offspring per adult).
Orally ingested nanoparticles may overcome the gastrointestinal barrier, reach the circulatory system, be distributed in the organism and cause adverse health effects. However, ingested nanoparticles have to pass through different physicochemical environments, which may alter their properties before they reach the intestinal cells. In this study, silver nanoparticles are characterised physicochemically during the course of artificial digestion to simulate the biochemical processes occurring during digestion. Their cytotoxicity on intestinal cells was investigated using the Caco-2 cell model. Using field-flow fractionation combined with dynamic light scattering and small-angle X-ray scattering, the authors found that particles only partially aggregate as a result of the digestive process. Cell viabilities were determined by means of CellTiter-Blue Ò assay, 4¢,6-diamidino-2-phenylindole-staining and real-time impedance. These measurements reveal small differences between digested and undigested particles (1-100 mg/ml or 1-69 particles/cell). The findings suggest that silver nanoparticles may indeed overcome the gastrointestinal juices in their particulate form without forming large quantities of aggregates. Consequently, the authors presume that the particles can reach the intestinal epithelial cells after ingestion with only a slight reduction in their cytotoxic potential. The study indicates that it is important to determine the impact of body fluids on the nanoparticles of interest to provide a reliable interpretation of their nano-specific cytotoxicity testing in vivo and in vitro.
— To examine the effect of dietary silver nanoparticles (Ag-NPs) on different organs of D. rerio as well as evaluating of its retention and toxicity under laboratory conditions. Four experimental diets were designed with a concentration of 1, 4, 6 and 8 mg.kg-1 (ppm) nanoparticles in the diet (named C1, C4, C6 and C8, respectively) and control group without any nanoparticles (C0). Fish were fed with dry feed for a period of 56 days. At the end of feeding trial, the fish were randomly selected for determining silver retention in different organs including liver, intestine, kidney and gill. Characterization of silver nanoparticles was determined by transmission electron microscopy (TEM) and UV-Vis spectrophotometer. Histological examination of tissues showed evidence of lesions or damage to tissues in treatments to silver nanoparticles. Examination of different organs revealed highest concentration of Ag-NPs in liver, gills and muscle in the ranking order. It can be concluded that supplementation of fish diet with Ag-NPs particles can induce sever histological lesions in Zebrafish tissues.
Agglomeration of Silver Nanoparticles in Sea Urchins
Proceedings of ICEPR'12 - 2nd International Conference on Environmental Pollution and Remediation, 2012
Silver nanoparticles (AgNPs) are one of the most important nanomaterials for toxicological study due to their extensive use in consumer products and their potential effects on both human and animal health, and the environment. There is, however, insufficient information on their impact on the marine environment. Here, we study the effect of AgNPs in sea urchin (Paracentrotus lividus) development by X-ray absorption near edge structure (XANES) and Fourier transform infrared (FTIR) spectroscopy. Agglomerated AgNPs were observed in sea urchin larva at 51 h after exposure to AgNPs with a concentration of 0.3 mg/L. XANES shows that agglomerated AgNPs contain oxidized Ag species complexed with S and O/N ligands. FTIR results confirm the presence of additional sulphur compounds suggestive of a biological response to the toxicity of AgNPs in the sea urchins. Additionally, it could be concluded from the FTIR results that there is a loss of calcite in the sea urchins exposed to AgNPs.
International Journal of Molecular Sciences
The aim of this study was to determine the effects of silver nanoparticles (AgNPs) on the morphology and enzymatic activity of butterfly splitfin (Ameca splendens). Individuals of both sexes, aged about five months, were exposed to AgNPs at concentrations of 0 (control group), 0.01, 0.1, and 1.0 mg/dm3 for 42 days. On the last day of the experiment, the fish were euthanized, subjected to standard histological processing (anterior intestine, liver, and gonads), and analysed for digestive enzyme activity in the anterior intestine and oxidative stress markers in the liver. Fish in the AgNP 0.01 and 0.1 groups had the lowest anterior intestinal fold and enterocyte height. However, there were no statistically significant changes in the digestive enzyme activity in the anterior intestine. Analysis of enzymatic activity in the liver showed an increase in superoxide dismutase activity in fish in the AgNP 0.1 group. Histological analyses showed that AgNPs inhibited meiotic divisions at proph...