S tters 2

PIb

M

1

CC

eitsibuapmWoacospnsovN

d

PCi

LA

1

2

RMf

fbravtia

haAsse

types of bacteria solubilised ions are the main cause of toxicity ofCuO.

doi:10.1016/j.toxlet.2011.05.951

280 Abstracts / Toxicology Le

2325nteraction of titanium dioxide nanoparticles withiomolecules at the lung interface

. Besse 1,∗, S. Morandat 2, K. El Kirat 1

Umr Cnrs 6600, Université de Technologie de Compiègne,ompiègne, France, 2 Umr Cnrs 6022, Université de Technologie deompiègne, Compiègne, France

Titanium dioxide nanoparticles (TiO2 NPs) are used in manyveryday life products (cosmetics, textile, paints, etc.). Under phys-ological conditions, NPs could get associated with biomolecules,hereby acquiring new properties. Moreover, in vitro and in vivotudies already showed the involvement of TiO2 in some lungnjuries and respiratory diseases. Thus, we have studied aiomimetic lipid model mimicking the pulmonary surfactant tonderstand how TiO2 NPs can associate with biomolecules at thelveolar interface. We have used vesicles with different lipid com-ositions to investigate the ability of TiO2 NPs to modify theembrane order using laurdan and prodan fluorescent probes.e also have measured the size of TiO2 NPs aggregates with

r without lipid vesicles using Dynamic Light Scattering (DLS)nd Environmental Scanning Electron Microscopy (ESEM). Fluores-ence experiments showed that TiO2 NPs increase the membranerder by interacting with the polar heads of lipids. Our resultsuggest that TiO2 NPs could alter lipid renewal dynamics of theroteolipidic monolayer covering the alveolar interface, which isecessary to maintain the surface tension at 0 mN/m. DLS mea-urements and ESEM images revealed a strong decrease in the sizef both anatase and rutile aggregates (∼200 nm) in the presence ofesicles. Such reduction of size could facilitate the crossing of TiO2Ps through the lung barrier.

oi:10.1016/j.toxlet.2011.05.949

2326ytotoxicity of AgPure silver nanoparticles in the human

ntestinal cell line Caco-2

. Böhmert 1,∗, U. Hansen 2, M. Girod 3, P. Knappe 3, B. Niemann 4,. Thünemann 3, A. Lampen 1

Federal Institute for Risk Assessment (BfR), Berlin, Germany,Federal Institute for Risk Assessment/Federal Institute for Materialsesearch and Testing, Berlin, Germany, 3 Federal Institute foraterials Research and Testing, Berlin, Germany, 4 Federal Institute

or Risk Assessment, Berlin, Germany

Purpose: Engineered nanomaterials may exhibit properties dif-ering significantly from those observed in the bulk materials,ecause of their small dimensions and large surface-to-volumeatio. Due to their unique qualities silver nanoparticles are used inwide range of consumer products. Even the use of nanoscaled sil-er hydrosol for nutritional purposes has been requested. Despitehe wide applications of silver nanoparticles, there is still lack ofnformation concerning the impact on human health after oralpplication.

Method: To investigate the effects of silver nanoparticles onuman intestinal cells, we monitored the reaction of Caco-2 cells,s a model for the first intestinal barrier of the human body, and

gPure silver nanoparticles. AgPure has already been used in con-umer products. The radius of gyration, hydrodynamic radius andize distribution were determined by SAXS and DLS. We studied theffects of AgPure on cell viability and proliferation by CellTiter-Blue

05S (2011) S180–S300

assay, DAPI staining and xCELLigence impedance measurement.Additionally, we tested for membrane damage with LDH assay, forapoptotic effects with Annexin-V/7AAD staining and for reactiveoxygen species with dichlorofluorescein assay.

Result: AgPure are spherical with metal-core radii of 7.4 nm andhydrodynamic radii of 22 nm with stabiliser. The size is Gaussian-distributed with a polydispersity of 17%. When proliferating Caco-2cells are exposed to AgPure, morphological abnormally adherenceand particle dose- and time-dependant cytotoxicity was observed.However, apoptosis or membrane damage did not occur, but resultsof the dichlorofluorescein assay suggested the formation of reactiveoxygen species as possible mechanism of cytotoxicity.

doi:10.1016/j.toxlet.2011.05.950

P2327Oxidative and genotoxic properties of CuO nanoparticles toEscherichia coli are due to solubilised Cu-ions

O. Bondarenko ∗, A. Ivask, A. Kahru

Laboratory of Molecular Genetics, National Institute of ChemicalPhysics and Biophysics, Tallinn, Estonia

Background and aims: One paradigm for explanation of toxic-ity mechanisms of nanoparticles (NPs) is their ability to inducethe formation of reactive oxygen species (ROS). However, incase of metal-containing NPs, it is still unclear to what extenttheir ROS generation is attributed to their nanosize and whatis the role of solubilized metal ions. Especially scarce is the(eco)toxicological information for CuO NPs. In this study, weconstructed two new recombinant luminescent Escherichia colistrains specifically inducible either by H2O2 or by chemicalscausing DNA damage and applied them to elucidate and dif-ferentiate the oxidative and genotoxic properties of CuO NPs.Methods: CuO nanoparticles (advertised size 30 nm) were pur-chased. CuO microparticles and CuSO4 were used as size andsolubility controls. E. coli K12::katGlux which luminescence isinduced by intracellular ROS and MC1061(pDEWrecAlux) inducibleby DNA damage were constructed. Recombinant Cu-sensing E. coliMC1061(pSLcueR/pDNPcopAlux) was used to quantify the solu-bilised Cu-ions released from CuO particles. Results: Upon exposureof recombinant E. coli sensor strains to CuO nanoparticles lumines-cence of both, ROS-sensor and DNA-damage sensor was inducedshowing the respective toxic properties of CuO NPs. Comparisonof the concentration-effect curves of recombinant Cu-sensing bac-teria upon exposure to CuO particle suspensions showed that theROS- as well as DNA-damage effects to these bacteria were due tosolubilised Cu-ions. It could be supposed that also in case of other