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Oxidative and genotoxic properties of CuO nanoparticles to Escherichia coli are due to solubilised Cu-ions
S280
Abstracts / Toxicology Letters 205S (2011) S180–S300
P2325 Interaction of titanium dioxide nanoparticles with biomolecules at the lung interface M. Besse 1,∗ , S. Morandat 2 , K. El Kirat 1 1
Umr Cnrs 6600, Université de Technologie de Compiègne, Compiègne, France, 2 Umr Cnrs 6022, Université de Technologie de Compiègne, Compiègne, France Titanium dioxide nanoparticles (TiO2 NPs) are used in many everyday life products (cosmetics, textile, paints, etc.). Under physiological conditions, NPs could get associated with biomolecules, thereby acquiring new properties. Moreover, in vitro and in vivo studies already showed the involvement of TiO2 in some lung injuries and respiratory diseases. Thus, we have studied a biomimetic lipid model mimicking the pulmonary surfactant to understand how TiO2 NPs can associate with biomolecules at the alveolar interface. We have used vesicles with different lipid compositions to investigate the ability of TiO2 NPs to modify the membrane order using laurdan and prodan fluorescent probes. We also have measured the size of TiO2 NPs aggregates with or without lipid vesicles using Dynamic Light Scattering (DLS) and Environmental Scanning Electron Microscopy (ESEM). Fluorescence experiments showed that TiO2 NPs increase the membrane order by interacting with the polar heads of lipids. Our results suggest that TiO2 NPs could alter lipid renewal dynamics of the proteolipidic monolayer covering the alveolar interface, which is necessary to maintain the surface tension at 0 mN/m. DLS measurements and ESEM images revealed a strong decrease in the size of both anatase and rutile aggregates (∼200 nm) in the presence of vesicles. Such reduction of size could facilitate the crossing of TiO2 NPs through the lung barrier. doi:10.1016/j.toxlet.2011.05.949
P2326 Cytotoxicity of AgPure silver nanoparticles in the human intestinal cell line Caco-2 L. Böhmert 1,∗ , U. Hansen 2 , M. Girod 3 , P. Knappe 3 , B. Niemann 4 , A. Thünemann 3 , A. Lampen 1 1
Federal Institute for Risk Assessment (BfR), Berlin, Germany, Federal Institute for Risk Assessment/Federal Institute for Materials Research and Testing, Berlin, Germany, 3 Federal Institute for Materials Research and Testing, Berlin, Germany, 4 Federal Institute for Risk Assessment, Berlin, Germany 2
Purpose: Engineered nanomaterials may exhibit properties differing significantly from those observed in the bulk materials, because of their small dimensions and large surface-to-volume ratio. Due to their unique qualities silver nanoparticles are used in a wide range of consumer products. Even the use of nanoscaled silver hydrosol for nutritional purposes has been requested. Despite the wide applications of silver nanoparticles, there is still lack of information concerning the impact on human health after oral application. Method: To investigate the effects of silver nanoparticles on human intestinal cells, we monitored the reaction of Caco-2 cells, as a model for the first intestinal barrier of the human body, and AgPure silver nanoparticles. AgPure has already been used in consumer products. The radius of gyration, hydrodynamic radius and size distribution were determined by SAXS and DLS. We studied the effects of AgPure on cell viability and proliferation by CellTiter-Blue
assay, DAPI staining and xCELLigence impedance measurement. Additionally, we tested for membrane damage with LDH assay, for apoptotic effects with Annexin-V/7AAD staining and for reactive oxygen species with dichlorofluorescein assay. Result: AgPure are spherical with metal-core radii of 7.4 nm and hydrodynamic radii of 22 nm with stabiliser. The size is Gaussiandistributed with a polydispersity of 17%. When proliferating Caco-2 cells are exposed to AgPure, morphological abnormally adherence and particle dose- and time-dependant cytotoxicity was observed. However, apoptosis or membrane damage did not occur, but results of the dichlorofluorescein assay suggested the formation of reactive oxygen species as possible mechanism of cytotoxicity. doi:10.1016/j.toxlet.2011.05.950
P2327 Oxidative and genotoxic properties of CuO nanoparticles to Escherichia coli are due to solubilised Cu-ions O. Bondarenko ∗ , A. Ivask, A. Kahru Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia Background and aims: One paradigm for explanation of toxicity mechanisms of nanoparticles (NPs) is their ability to induce the formation of reactive oxygen species (ROS). However, in case of metal-containing NPs, it is still unclear to what extent their ROS generation is attributed to their nanosize and what is the role of solubilized metal ions. Especially scarce is the (eco)toxicological information for CuO NPs. In this study, we constructed two new recombinant luminescent Escherichia coli strains specifically inducible either by H2 O2 or by chemicals causing DNA damage and applied them to elucidate and differentiate the oxidative and genotoxic properties of CuO NPs. Methods: CuO nanoparticles (advertised size 30 nm) were purchased. CuO microparticles and CuSO4 were used as size and solubility controls. E. coli K12::katGlux which luminescence is induced by intracellular ROS and MC1061(pDEWrecAlux) inducible by DNA damage were constructed. Recombinant Cu-sensing E. coli MC1061(pSLcueR/pDNPcopAlux) was used to quantify the solubilised Cu-ions released from CuO particles. Results: Upon exposure of recombinant E. coli sensor strains to CuO nanoparticles luminescence of both, ROS-sensor and DNA-damage sensor was induced showing the respective toxic properties of CuO NPs. Comparison of the concentration-effect curves of recombinant Cu-sensing bacteria upon exposure to CuO particle suspensions showed that the ROS- as well as DNA-damage effects to these bacteria were due to solubilised Cu-ions. It could be supposed that also in case of other types of bacteria solubilised ions are the main cause of toxicity of CuO. doi:10.1016/j.toxlet.2011.05.951
Abstracts / Toxicology Letters 205S (2011) S180–S300
P2325 Interaction of titanium dioxide nanoparticles with biomolecules at the lung interface M. Besse 1,∗ , S. Morandat 2 , K. El Kirat 1 1
Umr Cnrs 6600, Université de Technologie de Compiègne, Compiègne, France, 2 Umr Cnrs 6022, Université de Technologie de Compiègne, Compiègne, France Titanium dioxide nanoparticles (TiO2 NPs) are used in many everyday life products (cosmetics, textile, paints, etc.). Under physiological conditions, NPs could get associated with biomolecules, thereby acquiring new properties. Moreover, in vitro and in vivo studies already showed the involvement of TiO2 in some lung injuries and respiratory diseases. Thus, we have studied a biomimetic lipid model mimicking the pulmonary surfactant to understand how TiO2 NPs can associate with biomolecules at the alveolar interface. We have used vesicles with different lipid compositions to investigate the ability of TiO2 NPs to modify the membrane order using laurdan and prodan fluorescent probes. We also have measured the size of TiO2 NPs aggregates with or without lipid vesicles using Dynamic Light Scattering (DLS) and Environmental Scanning Electron Microscopy (ESEM). Fluorescence experiments showed that TiO2 NPs increase the membrane order by interacting with the polar heads of lipids. Our results suggest that TiO2 NPs could alter lipid renewal dynamics of the proteolipidic monolayer covering the alveolar interface, which is necessary to maintain the surface tension at 0 mN/m. DLS measurements and ESEM images revealed a strong decrease in the size of both anatase and rutile aggregates (∼200 nm) in the presence of vesicles. Such reduction of size could facilitate the crossing of TiO2 NPs through the lung barrier. doi:10.1016/j.toxlet.2011.05.949
P2326 Cytotoxicity of AgPure silver nanoparticles in the human intestinal cell line Caco-2 L. Böhmert 1,∗ , U. Hansen 2 , M. Girod 3 , P. Knappe 3 , B. Niemann 4 , A. Thünemann 3 , A. Lampen 1 1
Federal Institute for Risk Assessment (BfR), Berlin, Germany, Federal Institute for Risk Assessment/Federal Institute for Materials Research and Testing, Berlin, Germany, 3 Federal Institute for Materials Research and Testing, Berlin, Germany, 4 Federal Institute for Risk Assessment, Berlin, Germany 2
Purpose: Engineered nanomaterials may exhibit properties differing significantly from those observed in the bulk materials, because of their small dimensions and large surface-to-volume ratio. Due to their unique qualities silver nanoparticles are used in a wide range of consumer products. Even the use of nanoscaled silver hydrosol for nutritional purposes has been requested. Despite the wide applications of silver nanoparticles, there is still lack of information concerning the impact on human health after oral application. Method: To investigate the effects of silver nanoparticles on human intestinal cells, we monitored the reaction of Caco-2 cells, as a model for the first intestinal barrier of the human body, and AgPure silver nanoparticles. AgPure has already been used in consumer products. The radius of gyration, hydrodynamic radius and size distribution were determined by SAXS and DLS. We studied the effects of AgPure on cell viability and proliferation by CellTiter-Blue
assay, DAPI staining and xCELLigence impedance measurement. Additionally, we tested for membrane damage with LDH assay, for apoptotic effects with Annexin-V/7AAD staining and for reactive oxygen species with dichlorofluorescein assay. Result: AgPure are spherical with metal-core radii of 7.4 nm and hydrodynamic radii of 22 nm with stabiliser. The size is Gaussiandistributed with a polydispersity of 17%. When proliferating Caco-2 cells are exposed to AgPure, morphological abnormally adherence and particle dose- and time-dependant cytotoxicity was observed. However, apoptosis or membrane damage did not occur, but results of the dichlorofluorescein assay suggested the formation of reactive oxygen species as possible mechanism of cytotoxicity. doi:10.1016/j.toxlet.2011.05.950
P2327 Oxidative and genotoxic properties of CuO nanoparticles to Escherichia coli are due to solubilised Cu-ions O. Bondarenko ∗ , A. Ivask, A. Kahru Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia Background and aims: One paradigm for explanation of toxicity mechanisms of nanoparticles (NPs) is their ability to induce the formation of reactive oxygen species (ROS). However, in case of metal-containing NPs, it is still unclear to what extent their ROS generation is attributed to their nanosize and what is the role of solubilized metal ions. Especially scarce is the (eco)toxicological information for CuO NPs. In this study, we constructed two new recombinant luminescent Escherichia coli strains specifically inducible either by H2 O2 or by chemicals causing DNA damage and applied them to elucidate and differentiate the oxidative and genotoxic properties of CuO NPs. Methods: CuO nanoparticles (advertised size 30 nm) were purchased. CuO microparticles and CuSO4 were used as size and solubility controls. E. coli K12::katGlux which luminescence is induced by intracellular ROS and MC1061(pDEWrecAlux) inducible by DNA damage were constructed. Recombinant Cu-sensing E. coli MC1061(pSLcueR/pDNPcopAlux) was used to quantify the solubilised Cu-ions released from CuO particles. Results: Upon exposure of recombinant E. coli sensor strains to CuO nanoparticles luminescence of both, ROS-sensor and DNA-damage sensor was induced showing the respective toxic properties of CuO NPs. Comparison of the concentration-effect curves of recombinant Cu-sensing bacteria upon exposure to CuO particle suspensions showed that the ROS- as well as DNA-damage effects to these bacteria were due to solubilised Cu-ions. It could be supposed that also in case of other types of bacteria solubilised ions are the main cause of toxicity of CuO. doi:10.1016/j.toxlet.2011.05.951