Membrane technology to treat effluents with metal nanoparticles

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Subcellular partitioning kinetics, metallothionein response and oxidative damage in the marine mussel Mytilus galloprovincialis exposed to cadmium-based quantum dots

Publication . Rocha, Thiago Lopes; Gomes, Tânia; Durigon, Emerson Giuliani; Bebianno, Maria João

The environmental health impact of metal-based nanomaterials is of emerging concern, but their metabolism and detoxification pathways in marine bioindicator species remain unclear. This study investigated the role of subcellular partitioning kinetics, metallothioneins (MTs) response and oxidative damage (lipid peroxidation LPO) in the marine mussel Mytilus galloprovincialis exposed to CdTe quantum dots (QDs) in comparison with its dissolved counterpart. Mussels were exposed to QDs and dissolved Cd for 21 days at 10 mu g Cd L-1 followed by a 50 days depuration. Higher Cd concentrations were detected in fractions containing mitochondria, nucleus and lysosomes, suggesting potential subcellular targets of QDs toxicity inmussel tissues. Tissue specific metabolism patterns were observed in mussels exposed to both Cd forms. Although MT levels were directly associated with Cd in both forms, QDs subcellular partitioning is linked to biologically active metal (BAM), but no increase in LPO occurred, while in the case of dissolved Cd levels are in the biologically detoxified metal (BDM) form, indicating nano-specific effects. Mussel gills showed lower detoxification capability of QDs, while the digestive gland is the major tissue for storage and detoxification of both Cd forms. Both mussel tissues were unable to completely eliminate the Cd accumulated in the QDs form (estimated half-life time > 50 days), highlighting the potential source of Cd and QDs toxicity for human and environmental health. Results indicate tissue specific metabolism patterns and nano-specific effects in marine mussel exposed to QDs. (C) 2016 Elsevier B.V. All rights reserved.

2016-06Journal article

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Multibiomarker assessment of cadmium-based quantum dots effects in the marine mussel Mytilus galloprovincialis

Publication . Rocha, Thiago Lopes; Bebianno, Maria João

Nanotechnology and use of engineered nanomaterials (ENMs) may improve life quality, economic growth and environmental quality, but their environmental risk in the marine environment is scarce. Properties of quantum dots (QDs), namely small size, unique optical and biofunctional properties, allow their use in nanomedicine, biology and electronics, but also confer different toxicity compared to its dissolved counterparts. Accordingly, this thesis assessed the toxicokinetics (TK), mode of action (MoA) and toxicity of CdTe QDs (10 μg Cd L-1) in the marine mussel Mytilus galloprovincialis, compared to dissolved Cd for 21 days followed by 50 days depuration. For this purpose, Cd distribution in different mussel tissues, subcellular fractions and biodeposits were analysed, TK parameters estimated (accumulation and elimination rates, bioconcentration factor and half-life time) and multibiomarkers assessed: immunotoxicity (density, viability and differential cell count of hemocytes), cytotoxicity (lysosomal membrane stability - LMS), genotoxicity (DNA damage and nuclear anomalies), oxidative stress (superoxide dismutase - SOD, catalase - CAT, glutathione peroxidase - GPx and glutatione-S-Transferase - GST), metal exposure (metallothionein - MT), oxidative damage (lipid peroxidation - LPO), tissue-level biomarkers (17 histomorphometric parameters of digestive tubules, inflammatory and histopathological conditions indices) and proteomic responses. Results showed that the digestive gland plays an important role in storage, metabolism and detoxification of QDs, while gills have similar functions for dissolved Cd and the hemolymph in transport, distribution and regulation of QDs. Tissue specific metabolism patterns and nano-specific effects were identified, wherein the MoA and toxicity of QDs in mussels is time dependent and involve oxidative stress, immune response, DNA damage and differential protein expression. Mussels were unable to completely eliminate the QDs (t1/2 > 50 days), highlighting their potential source of toxicity for human health and environment. M. galloprovincialis is a significant target of QDs ecotoxicity and represent a suitable biomonitor for assess their environment risk.

2016-07-25Doctoral thesis

Open access

Effects of silver nanoparticles exposure in the mussel Mytilus galloprovincialis

Publication . Gomes, Tânia; Pereira, Catarina; Cardoso, Cátia; Serrão Sousa, Vânia; Ribau Teixeira, Margarida; Pinheiro, José P.; Bebianno, Maria João

Silver nanoparticles (Ag NPs) have emerged as one of the most commonly used NPs in a wide range of industrial and commercial applications. This has caused increasing concern about their fate in the environment as well as uptake and potential toxicity towards aquatic organisms. Accordingly, mussels Mytilus galloprovincialis were exposed to 10 μg L(-1) of Ag NPs and ionic silver (Ag+) for 15 days, and biomarkers of oxidative stress and metal accumulation were determined. Accumulation results show that both Ag NPs and Ag+ accumulated in both gills and digestive glands. Antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) were activated by Ag NPs and Ag+, showing different antioxidant patterns in both gills and digestive glands. Moreover, metallothionein was inducted in gills, directly related to Ag accumulation, while in the digestive glands only a small fraction of Ag seems to be associated with this protein. Lipid peroxidation was higher in gills exposed to Ag NPs, whereas in the digestive glands only Ag+ induced lipid peroxidation. Ag NPs and Ag+ cause oxidative stress with distinct modes of action and it's not clear if for Ag NPs the observed effects are attributed to free Ag+ ions associated with the nanoparticle effect.

2014Journal article

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Histopathological assessment and inflammatory response in the digestive gland of marine mussel Mytilus galloprovincialis exposed to cadmium-based quantum dots

Publication . Rocha, Thiago Lopes; Saboia-Morais, Simone Maria Teixeira; Bebianno, Maria

Although tissue-level biomarkers have been widely applied in environmental toxicology studies, the knowledge using this approach in marine invertebrates exposed to engineered nanomaterials (ENMs) remains limited. This study investigated histopathological alterations and inflammatory responses induced by Cd-based quantum dots (QDs), in comparison with their dissolved counterparts, in the marine mussel Mytilus galloprovincialis. Mussels were exposed to CdTe QDs and dissolved Cd at the same concentration (10 mu g Cd L-1) for 14 days and a total of 15 histopathological alterations and 17 histomorphometric parameters were analysed in the digestive gland along with the determination of histopathological condition indices (I-h). A multivariate analysis showed that the mussel response to QDs was more related to exposure time, inflammatory conditions (frequency of haemocytic infiltration and granulocytomas) and changes of cell-type composition (especially the rate between basophilic and digestive cells) when compared to dissolved Cd, while the response to dissolved Cd was associated with histomorphometric parameters of the epithelium and lumen of digestive tubules and increase of the atrophic tubule frequency. Both Cd forms induced higher I-h compared to unexposed mussels indicating a significant decrease in the health status of digestive gland in a Cd form and time-dependent pattern. Results indicate that the multiparametric tissue-level biomarkers in the digestive gland provide a suitable approach to assess the ecotoxicity and mode of action of metal-based ENMs in marine bivalves. (C) 2016 Elsevier B.V. All rights reserved.

2016-08Journal article

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Nanofiltration ability to remove copper oxide and silver nanoparticles: The role of surface charge and size

Publication . Serrão Sousa, Vânia; Santos, C.; Ribau Teixeira, Margarida; Marsh, N.

This work pretends to study the performance of nanofiltration (NF) membranes in the removal of copper oxide and silver nanoparticles (NPs) and evaluate the role of surface charge and size of the NPs on this performance. Results demonstrate that positive charged CuO NPs are adsorbed onto negatively charged NF membrane, whereas for the negatively charged Ag NPs the adsorption on the membrane surface is much lower. For CuO NPs, NF270 is very efficient and the main mechanism of removal seems to be adsorption. For Ag NPs, removals are low due to the hydrodynamic diameter of the NPs at this pH compared to the membrane cut-off (similar to 170 Da).

2012Conference object

Open access