Timing, hosts and locations of (grouped) events of NanoImpactNet

financial/administrative coordination cost control, deadlines,
contacts with the EU and dissemination.
5 NanoReTox Results
During its first three years, NanoReTox has produced the following
key results:
5.1 Results from WP1 and WP2
WP1 has produced a range of well-characterised sets of ZnO, CuO,
TiO 2, SiO 2, Ag, Au and CdS nanoparticles. Some of the particles
were produced by the industry partners and some tailored to show
properties that vary systematically, so that robust links to toxicity
can be made. Reproducible protocols for all the syntheses have
been developed and the produced sets of nanoparticles were
thoroughly characterised and tested in a variety of (eco)toxicity
experiments in subsequent WPs.
WP2 tested the stability of the above particles in a variety of
conditions, with the aim to understand their behaviour in
biological/environmental media as well as their overall
physicochemical response to changes of conditions such as
temperature, pH and ionic strength. Major findings include: a)
dissolution results, which indicated increased ion release of metal
ions from CuO and ZnO nanoparticles compared to their bulk
counterparts, while TiO 2 remains relatively insoluble; b) the effect
of temperature which appears to be reversible, i.e. an increase in
size is observed while the samples are heated, suggesting
aggregation, but temperature decrease is sufficient to redisperse
the particles; c) the behaviour of nanoparticles in different media
shows different patterns depending on the composition of the
nanoparticles and the type of stabilisation; however a common
feature is aggregation even at modest increases in ionic strength;
the presence of organics, humic acid or albumin, induces moderate
aggregation.
5.2 Results from WP3 and WP4
The main objective of these two WPs was to test nanoparticle
toxicity on a selection of aquatic organisms and conditions in vivo
and in vitro. In WP3 (in vivo), a wide range of species belonging to
different taxonomic groups and with different biological traits
were tested: Bivalve molluscs (Scrobicularia plana, Mytilus
galloprovincialis, Macoma balthica), a gastropod (Peringia ulvae),
two species of polychaetes (Nereis diversicolor, Capitella teleta) as
representatives of the estuarine and marine environment and
three freshwater species, two gastropods (Potamopyrgus
antipodarum, Lynamaea stagnalis) and zebrafish (Danio rerio,
embryos). The experiments included food, water- and sedimentexposure
treatments. Toxicity endpoints included both
subindividual-level effects (biomarkers) and individual-level effects
(mortality/survival, hatching, reproduction, malformations,
behaviour, feeding rate). A number of particles from a variety of
sources and a wide range of doses have already been tested (CuO,
Ag, Au, TiO 2, ZnO) and produced the following findings: (1) a set of
preliminary indications of ecotoxicity (oxidative-stress,
genotoxicity, cytotoxicity, behaviour impairments, malformations,
mortality, reproduction, hatching), as a function of nanoparticle
NanoSafetyCluster - Compendium 2012
properties, (2) demonstration that all of the metal forms (ionic,
NPs, bulk) were bioavailable and bioaccumulated by some
organisms, even of aggregated NPs in seawater; (3) demonstration
that metal containing NPs yield bioavailable metals, more so than
bulk or micron sized particles; (4) usually in water-exposure
treatment, ionic forms were more bioavailable and/or toxic than
NPs. Bioavailability of Ag from citrate-capped Ag NPs in Peringia
ulvae was 2 fold less bioavailable than dissolved Ag. In Zebrafish
embryos, ionic silver was the most toxic compound, (5) a
detectable release in exposure medium of Ag from lactose-AgNPs
has been shown whereas no detectable release of metal was
observed with citrate-Ag NPs or CuO NPs (6) a particle size-related
differences in bioavailablity and toxicity effects has been observed
in the case of Ag NPs; the smallest ones were the most toxic in
Zebrafish embryos. For mollusks, uptake rates in P. antipodarum
were faster for the smaller-sized Cu particles. In contrast, the
biggest Au NPs induced higher bioaccumulation than smaller ones
in S. plana. However, AgNPs-size did not affect bioaccumulation in
both polychaetes species (N. diversicolor, C. teleta), (6) differences
in bioavailability and toxicity according to the routes of exposure:
the response of biomarkers of defence in S. plana was more
important after dietary than after waterborne exposure to Ag. In
the snail (L. stagnalis) 67 Zn was assimilated from 67 ZnO NPs mixed
with diatoms food and the mixture inhibits ingestion rates in
animals at higher Zn concentrations, (7) the stable isotope tracing
approach is suitable to explore ecotoxicity effects of NPs ( 67 ZnO)
in environmentally realistic conditions (8) establishing of
interspecies differences in bioaccumulation and toxicity effects
that may be particle specific, however the species most sensitive
to one type are not necessary most sensitive to another type.
5.3 Results from WP5 and WP6
In vitro models were used to examine cellular responses to
nanoparticles. The work was based on the hypothesis that the
cellular reactivity of the particles will critically depend both on the
target tissue and the function of the cell type within that tissue.
Cellular and molecular reactivity of selected metal nanoparticles
were investigated in a) primary mammalian and human cells and b)
in a panel of established human cell lines.
.A relatively wide range of tissue sources have been covered, to
include the lung, skin, immune blood cells, gut, kidney and liver. A
wide range of doses of the nanoparticles were studied, between
0.1 and 100μg/ml for all the studies except those on the human skin
organ model, where the doses were increased to 100,000 μg/ml
topically, and 800μg/ml systemically, to represent that used in
sunscreen products. Key findings include: a) In studies of lung and
skin models (Imperial and DSL), which investigated cytotoxicity
(MTT assay), oxidative stress (ROS and glutathione levels) and
release of pro-inflammatory mediators (IL-6, IL-8, MCP-1 and
TNFα), TiO 2 was found to have very little adverse reactivity,
regardless of whether it was in the bulk form (BAN, BRU), mixed
bulk and nanoparticles (INT), or nanoparticles (TiO 2 1-4, TiO 2 10, 50
and 100nm, P25). In studies of lung and skin cells with Au 5, 15 and
40nm, again, the particles had no significant adverse effects with
respect to the above indices. b) In a colony forming efficiency
assay, CFE, 5 cell lines were studied, A549, Balb/3T3, MDCK, HepG2
and Caco-2 representing lung, kidney, liver and gut. TiO 2 10, 50 and
100nm, and Au 5, 15 and 40nm, were studied. There was no effect
of the TiO2, regardless of size. Neither was there any effect of Au
15 and 40. Interestingly, Au 5 caused a striking dose-related loss of
Compendium of Projects in the European NanoSafety Cluster 173