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Impact of SiO2 NP-allergen interaction on dendritic cell function altering the immune response, eventually resulting in a harmless, beneficial outcome in terms of allergic reactivity.

Understanding the ability of fish intestinal cells to act as a barrier for nanoparticle (NP) uptake and their effects is of significance from an environmental perspective as well as for human health, for which fish serves as an important nutrient source. We used an in vitro intestinal barrier model, based on rainbow trout intestinal (RTgutGC) cells, to elaborate the toxicity and translocation of five types of metal-based NPs. The NPs were polyvinylpyrrolidone (PVP)-coated Ag NPs, uncoated Ag NPs, CuO NPs, ZnO NPs and TiO2 NPs. In conventional monolayers on impermeable supports, cell viability declined according to classical sigmoidal dose–response curves with EC50 values between 0.28 mg L−1 and >100 mg L−1 in the following rank order, from the most toxic (lowest EC50) to the least toxic (highest EC50): PVP–Ag NPs < uncoated Ag NPs < CuO NPs < ZnO NPs < TiO2 NPs. When cells were cultured on permeable membranes to mimic an intestinal lumen and a blood-facing side, however, a much higher resistance of the cells towards NP-induced stress was noted with little to no impact on cell viability or barrier integrity. Yet, increased levels of Ag, Cu and Zn but not Ti were measured in the blood-side mimicking (basolateral) compartment, indicating translocation of Ag, Cu, and Zn-based NPs or ions liberated from them through the epithelial cell layer. Since especially CuO NPs appeared to be translocated as intact particles, they were investigated in more detail. A time- and temperature-dependent analysis, involving different endocytosis inhibitors, suggested that CuO NPs were translocated through the epithelium by apical caveolae-mediated endocytosis followed by delayed export onto the basolateral side. These data give valuable insights into NP uptake by, and translocation through, the fish intestinal epithelium and will be of value for future research on the molecular mechanisms of NPs that enter the fish via this critical uptake route.

The number of consumer products containing nanoparticles (NPs) experienced a rapid increase during the past decades. However, most studies of nanosafety have been conducted using only pure NPs produced in the laboratory, while the interactions with other ingredients in consumer products have rarely been considered so far. In the present study, we investigated such interactions-with a special focus on modern lifestyle products (MLPs) used by adolescents. An extensive survey was undertaken at different high schools all over Austria to identify MLPs that either contain NPs or that could come easily in contact with NPs from other consumer products (such as TiO2 from sunscreens). Based on the results from a survey among secondary schools students, we focused on ingredients from Henna tattoos (2-hydroxy-1,4-naphtoquinone, HNQ, and p-phenylenediamine, PPD), fragrances (butylphenyl methylpropional, known as Lilial), cosmetics and skin-care products (four different parabens). As a cellular model, we decided to use neonatal normal human dermal fibroblasts (nNHDF), since skin contact is the main route of exposure for these compounds. TiO2 NPs interacted with these compounds as evidenced by alterations in their hydrodynamic diameter observed by nanoparticle tracking analysis. Combinations of TiO2 NPs with the different MLP components did not show altered cytotoxicity profiles compared to MLP components without TiO2 NPs. Nevertheless, altered cellular glutathione contents were detected after incubation of the cells with Lilial. This effect was independent of the presence of TiO2 NPs. Testing mixtures of NPs with other compounds from consumer products is an important approach to achieve a more reliable safety assessment.

International audience; The coming years are expected to bring rapid changes in the nanotechnology regulatory landscape, with the establishment of a new framework for nano-risk governance, in silico approaches for characterisation and risk assessment of nanomaterials, and novel procedures for the early identification and management of nanomaterial risks. In this context, Safe(r)-by-Design (SbD) emerges as a powerful preventive approach to support the development of safe and sustainable (SSbD) nanotechnology-based products and processes throughout the life cycle. This paper summarises the work undertaken to develop a blueprint for the deployment and operation of a permanent European Centre of collaborating laboratories and research organisations supporting safe innovation in nanotechnologies. The proposed entity, referred to as “the Centre”, will establish a ‘one-stop shop’ for nanosafety-related services and a central contact point for addressing stakeholder questions about nanosafety. Its operation will rely on significant business, legal and market knowledge, as well as other tools developed and acquired through the EU-funded EC4SafeNano project and subsequent ongoing activities. The proposed blueprint adopts a demand-driven service update scheme to allow the necessary vigilance and flexibility to identify opportunities and adjust its activities and services in the rapidly evolving regulatory and nano risk governance landscape. The proposed Centre will play a major role as a conduit to transfer scientific knowledge between the research and commercial laboratories or consultants able to provide high quality nanosafety services, and the end-users of such services (e.g., industry, SMEs, consultancy firms, and regulatory authorities). The Centre will harmonise service provision, and bring novel risk assessment and management approaches, e.g. in silico methodologies, closer to practice, notably through SbD/SSbD, and decisively support safe and sustainable innovation of industrial production in the nanotechnology industry according to the European Chemicals Strategy for Sustainability.

Over 100 years ago, Paul Ehrlich first proposed the side-chain theory to explain how living cells mount an immune response in reaction to an infection. His theory stated that upon the encounter of a threat, cells express side-chains to bind dangerous toxins. These side-chains,cwhich he later named receptors, can break off the cell and circulate throughout the body (i.e. antibodies). Specific antibodies link to particular antigens in the same way that Emil Fischer proposed enzymes bind to their receptors, “as lock and key”. Ehrlich described these so-called “keys” or antibodies as “magic bullets”, which target toxins without harming the body. In recent years, research has focused on using antibodies not only for detection of infection, but also as aids for drug targeting. Thereby, antibodies are bound to the surface of carriers (e.g. nanoparticles) and facilitate a directed transport to a specific organ or site in the body. Aptamer- peptide- or folic acid-doped carriers furthermore have been shown to specifically target cancer cells. By using hydrophilic structures as carriers (e.g. polyethylene glycol), negative side effects resulting from the accumulation of innate proteins can be prevented. Currently, there are drug carriers in the pre-clinical development phase for the treatment of bowel cancer. Thereby, nano polymer capsules coated with a specific antibody are used to target a glycoprotein expressed on bowel cancer cells. The polymers have a size of approximately 500 nm and are produced with a so-called “layer-by-layer” procedure. Once the carrier has reached its target site, the drug needs to be released in a controlled manner. This can be facilitated, for example, by applying a magnetic field in the case of iron oxide particles. Once these particles are taken up by the cells, magnetic radiation can be used to excite the particles, resulting in the rupture of the cell and subsequent cell death.

Gold (Au) and silver (Ag) nanopartucles (NPs) are frequently used in medicine (drug delivery, wound dressings) but also more and more icorporated in every-day life products, such as functional clothing. Therfore, a comprehensive dafety assessment of such particles is essential. Teh aim of this work was the investigation of the suitability of standard DIN-EN-ISO protocolis for cytotoxicity assessment of NPs.

The number of consumer products containing nanoparticles (NPs) experienced a rapid increase during the past decades. However, most studies of nanosafety have been conducted using only pure NPs produced in the laboratory, while the interactions with other ingredients in consumer products have rarely been considered so far. In the present study, we investigated such interactions—with a special focus on modern lifestyle products (MLPs) used by adolescents. An extensive survey was undertaken at different high schools all over Austria to identify MLPs that either contain NPs or that could come easily in contact with NPs from other consumer products (such as TiO2 from sunscreens). Based on the results from a survey among secondary schools students, we focused on ingredients from Henna tattoos (2-hydroxy-1,4-naphtoquinone, HNQ, and p-phenylenediamine, PPD), fragrances (butylphenyl methylpropional, known as Lilial), cosmetics and skin-care products (four different parabens). As a cellular model, we decided to use neonatal normal human dermal fibroblasts (nNHDF), since skin contact is the main route of exposure for these compounds. TiO2 NPs interacted with these compounds as evidenced by alterations in their hydrodynamic diameter observed by nanoparticle tracking analysis. Combinations of TiO2 NPs with the different MLP components did not show altered cytotoxicity profiles compared to MLP components without TiO2 NPs. Nevertheless, altered cellular glutathione contents were detected after incubation of the cells with Lilial. This effect was independent of the presence of TiO2 NPs. Testing mixtures of NPs with other compounds from consumer products is an important approach to achieve a more reliable safety assessment.

BackgroundAllergen-specific immunotherapy via the skin targets an area rich in antigen presenting cells, but can be associated with local and systemic side effect. Allergen-polysaccharide neoglycogonjugates can increase immunization efficacy by targeting and activating dendritic cells via C-type lectin receptors and reduce side effects.ObjectiveWe investigated the immunogenicity, allergenicity and therapeutic efficacy of laminarin-ovalbumin neoglycoconjugates (LamOVA).MethodsThe biological activity of LamOVA was characterizedin vitrousing bone marrow derived dendritic cells. Immunogenicity and therapeutic efficacy was analyzed in BALB/c mice. Epicutaneous immunotherapy (EPIT) was performed using fractional infrared laser ablation to generate micropores in the skin and the effects of LamOVA on blocking IgG, IgE, cellular composition of BAL, lung, and spleen, lung function, and T cell polarization was assessed.ResultsConjugation of laminarin to ovalbumin reduced its IgE binding capacity 5-fold and increased its immunogenitiy 3-fold in terms of IgG generation. EPIT with LamOVA induced significantly higher IgG levels than OVA, matching the levels induced by s.c. injection of OVA/alum (SCIT). EPIT was equally effective as SCIT in terms of blocking IgG induction and suppression of lung inflammation and airway hyperresponsiveness, but SCIT was associated with a higher level of therapy induced IgE and TH2 cytokines. EPIT with LamOVA induced significantly lower local skin reactions during therapy compared to unconjugated OVA.ConclusionConjugation of the allergen to laminarin increased its immunogenicity while at the same time reducing local side effects. LamOVA EPIT via laser generated micropores is safe and equally effective to SCIT with alum, without the need for adjuvant.

Mastery of strengthening strategies to achieve high-capacity anodes for lithium-ion batteries can shed light on understanding the nature of diffusion-induced stress and offer an approach to use submicro-sized materials with an ultrahigh capacity for large-scale batteries. Here, we report solute strengthening in a series of silicon (Si)—germanium (Ge) alloys. When the larger solute atom (Ge) is added to the solvent atoms (Si), a compressive stress is generated in the vicinity of Ge atoms. This local stress field interacts with resident dislocations and subsequently impedes their motion to increase the yield stress in the alloys. The addition of Ge into Si substantially improves the capacity retention, particularly in Si0.50Ge0.50, aligning with literature reports that the Si/Ge alloy showed a maximum yield stress in Si0.50Ge0.50. In situ X-ray diffraction studies on the Si0.50Ge0.50 electrode show that the phase change undergoes three subsequent steps during the lithiation process: removal of surface oxide layer, formation of cluster-size Lix(Si,Ge), and formation of crystalline Li15(Si,Ge)4. Furthermore, the lithiation process starts from higher index facets, i.e., (220) and (311), then through the low index facet (111), suggesting the orientation-dependence of the lithiation process in the Si0.50Ge0.50 electrode.

Nanotechnology is a fast growing field and already a multi-billion dollar market with numerous products available for consumers. TiO2 and SiO2 are by mass the most produced nanomaterials and, thus, of particular interest regarding their biological effects upon inhalation – especially in combination with other inhalable biomolecules such as allergens. We investigated the protein-binding capacity of these two nanomaterials and present detailed uptake profiles of protein-conjugated TiO2 or SiO2 nanoparticles (NPs) in A549 lung epithelial and THP-1 macrophage-like cells. TiO2 and SiO2 NPs (both with a hydrodynamic diameter of about 150 nm) are able to bind bovine serum albumin (BSA), green fluorescent protein (GFP) and the major birch pollen allergen Bet v 1 in substantial amounts that suggest protein monolayers around the particles. GFP-conjugated TiO2 and SiO2 NPs were taken up in A549 and THP-1 cells in a time-dependent manner as demonstrated by confocal laser scanning microscopy, flow cytometry and life cell imaging. By the aid of fluorescent proteins (GFP or fluorescently labeled Bet v 1) we found that both, the NPs and the conjugated proteins entered the cells. Using A549/THP-1 co-cultures, we showed that the majority of SiO2 NPs is taken up by THP-1 cells; however, also A549 cells take up significant amounts of particles when co-cultured with THP-1 macrophage-like cells. The here discussed data provide valuable insights into protein (allergen) delivery by NPs at the lung epithelial barrier.

Silver nanoparticles (Ag NPs) are widely used in consumer products especially because of their antimicrobial properties. However, this wide usage of Ag NPs is accompanied by their release into the environment where they will be rapidly transformed to other silver species – especially silver sulfide (Ag2S). In the present study, we synthesized Ag NPs and sulfidized them to obtain a core-shell system Ag@Ag2S NPs. Both types of particles form stable dispersions with hydrodynamic diameters of less than 100 nm when diluted in water, but tend to form micrometer-sized agglomerates in biological exposure media. Application of Ag and Ag@Ag2S NPs to rainbow trout intestinal cells (RTgutGC) resulted in a concentration-dependent cytotoxicity for both types of particles, as assessed by a three-endpoint assay for metabolic activity, membrane integrity and lysosomal integrity. The Ag NPs were shown to be slightly more toxic than the Ag@Ag2S NPs. Adding Ag or Ag@Ag2S NPs to RTgutGC cells, grown on a permeable membrane to mimic the intestinal barrier, revealed considerable accumulation of silver for both types of particles. Indeed, the cells significantly attenuated the NP translocation, allowing only a fraction of the metal to translocate across the intestinal epithelium. These findings support the notion that the intestine constitutes an important sink for Ag NPs and that, despite the reduced cytotoxicity of a sulfidized NP form, the particles can enter fish where they may constitute a long-term source for silver ion release and cytotoxicity.

Even with the widespread use of nanomaterials (NMs) in everyday life, consumer knowledge about the functionality, benefits, and possible dangers of nanotechnology (NT) is still modest. As with any developing technology, its public perception has direct implications on future policies and has to be taken into account by academia and industry alike. As part of the “Nan-O-Style” interdisciplinary research project, an online survey was conducted using a Citizen Science-guided approach. The main goal was to evaluate the current levels of knowledge and the attitude towards NT among the general Austrian public and to determine how differing sociodemographic factors may affect these. Over the course of 17 months, a total of 1067 responses were collected and quantitatively analysed. We found that while Austrians display a generally optimistic view and a positive attitude towards NT, there are still remaining concerns about its safety and possible risks. Participants expressed great desire for more information about NT and its applications, as well as for clear labelling and transparency of products containing NMs. Notably, we found that age did not affect the general attitude towards NT nor the levels of NT awareness. While participants with a university degree were generally more knowledgeable on this specific topic, surprisingly, there were no significant differences in the attitude towards NT among people from different educational backgrounds. Similar to previous studies, we observed that male participants demonstrated a more positive attitude towards NT and scored slightly higher in our NT quiz compared to female participants. However, female participants voiced greater desire for more information and transparency regarding NMs. Interestingly, while participants with a negative attitude towards NT scored lowest on the NT quiz, they also expressed the least interest in receiving more NT-related information. This illustrates a difficulty in mitigating public aversion solely by providing more information.

A new prototype air-liquid interface (ALI) exposure system, a flatbed aerosol exposure chamber termed NAVETTA, was developed to investigate deposition of engineered nanoparticles (NPs) on cultured human lung A549 cells directly from the gas phase. This device mimics human lung cell exposure to NPs due to a low horizontal gas flow combined with cells exposed at the ALI. Electrostatic field assistance is applied to improve NP deposition efficiency. As proof-of-principle, cell viability and immune responses after short-term exposure to nanocopper oxide (CuO)-aerosol were determined. We found that, due to the laminar aerosol flow and a specific orientation of inverted transwells, much higher deposition rates were obtained compared to the normal ALI setup. Cellular responses were monitored with postexposure incubation in submerged conditions, revealing CuO dissolution in a concentration-dependent manner. Cytotoxicity was the result of ionic and nonionic Cu fractions. Using the optimized inverted ALI/postincubation procedure, pro-inflammatory immune responses, in terms of interleukin (IL)-8 promoter and nuclear factor kappa B (NFκB) activity, were observed within short time, i.e. One hour exposure to ALI-deposited CuO-NPs and 2.5 h postincubation. NAVETTA is a novel option for mimicking human lung cell exposure to NPs, complementing existing ALI systems.

Metal-containing nanoparticles (NPs) are currently used for various biomedical applications. Since such NPs are able to enter the brain, the cells of this organ have to deal with NPs and with NP-derived metal ions. In brain, astrocytes are considered to play a key function in regulating metal homeostasis and in protecting other brain cells against metal toxicity. Thus, among the different types of brain cells, especially astrocytes are of interest regarding the uptake and the handling of metal-containing NPs. This article summarizes the current knowledge on the consequences of an exposure of astrocytes to NPs. Special focus will be given to magnetic iron oxide nanoparticles (IONPs) and silver nanoparticles (AgNPs), since the biocompatibility of these NPs has been studied for astrocytes in detail. Cultured astrocytes efficiently accumulate IONPs and AgNPs in a time-, concentration- and temperature-dependent manner by endocytotic processes. Astrocytes are neither acutely damaged by the exposure to high concentrations of NPs nor by the prolonged intracellular presence of large amounts of accumulated NPs. Although metal ions are liberated from accumulated NPs, NP-derived iron and silver ions are not exported from astrocytes but are rather stored in proteins such as ferritin and metallothioneins which are synthesized in NP-treated astrocytes. The efficient accumulation of large amounts of metal-containing NPs and the upregulation of proteins that safely store NP-derived metal ions suggest that astrocytes protect the brain against the potential toxicity of metal-containing NPs.

Within the FP7 EU project NanoValid a consortium of six partners jointly investigated the hazard of silver nanoparticles (AgNPs) paying special attention to methodical aspects that are important for providing high-quality ecotoxicity data. Laboratories were supplied with the same original stock dispersion of AgNPs. All partners applied a harmonised procedure for storage and preparation of toxicity test suspensions. Altogether ten different toxicity assays with a range of environmentally relevant test species from different trophic levels were conducted in parallel to AgNP characterisation in the respective test media. The paper presents a comprehensive dataset of toxicity values and AgNP characteristics like hydrodynamic sizes of AgNP agglomerates and the share (%) of Ag+-species (the concentration of Ag+-species in relation to the total measured concentration of Ag). The studied AgNP preparation (20.4 ± 6.8 nm primary size, mean total Ag concentration 41.14 mg/L, 46–68% of soluble Ag+-species in stock, 123.8 ± 12.2 nm mean z-average value in dH2O) showed extreme toxicity to crustaceans Daphnia magna, algae Pseudokirchneriella subcapitata and zebrafish Danio rerio embryos (EC50

Iron oxide nanoparticles (IONP) are currently being studied as green magnet resonance imaging (MRI) contrast agents. They are also used in huge quantities for environmental remediation and water treatment purposes, although very little is known on the consequences of such applications for organisms and ecosystems. In order to address these questions, we synthesised polyvinylpyrrolidone-coated IONP, characterised the particle dispersion in various media and investigated the consequences of an IONP exposure using an array of biochemical and biological assays. Several theoretical approaches complemented the measurements. In aqueous dispersion IONP had an average hydrodynamic diameter of 25 nm and were stable over six days in most test media, which could also be predicted by stability modelling. The particles were tested in concentrations of up to 100 mg Fe per L. The activity of the enzymes glutathione reductase and acetylcholine esterase was not affected, nor were proliferation, morphology or vitality of mammalian OLN-93 cells although exposure of the cells to 100 mg Fe per L increased the cellular iron content substantially. Only at this concentration, acute toxicity tests with the freshwater flea Daphnia magna revealed slightly, yet insignificantly increased mortality. Two fundamentally different bacterial assays, anaerobic activated sludge bacteria inhibition and a modified sediment contact test with Arthrobacter globiformis, both rendered results contrary to the other assays: at the lowest test concentration (1 mg Fe per L), IONP caused a pronounced inhibition whereas higher concentrations were not effective or even stimulating. Preliminary and prospective risk assessment was exemplified by comparing the application of IONP with gadolinium-based nanoparticles as MRI contrast agents. Predicted environmental concentrations were modelled in two different scenarios, showing that IONP could reduce the environmental exposure of toxic Gd-based particles by more than 50%. Application of the Swiss “Precautionary Matrix for Synthetic Nanomaterials” rendered a low precautionary need for using our IONP as MRI agents and a higher one when using them for remediation or water treatment. Since IONP and (considerably more reactive) zerovalent iron nanoparticles are being used in huge quantities for environmental remediation purposes, it has to be ascertained that these particles pose no risk to either human health or to the environment.

Magnetic iron oxide nanoparticles (Fe-NPs) are considered for various biomedical and neurobiological applications that involve the presence of external magnetic fields. However, little is known on the effects of a magnetic field on the uptake of such particles by brain cells. Cultured brain astrocytes accumulated dimercaptosuccinate-coated Fe-NP in a time-, temperature-, and concentration-dependent manner. This accumulation was strongly enhanced by the presence of the magnetic field generated by a permanent neodymium iron boron magnet that had been positioned below the cells. The magnetic field-induced acceleration of the accumulation of Fe-NP increased almost proportional to the strength of the magnetic field applied, increasing the cellular-specific iron content from an initial 10 nmol/mg protein within 4 h of incubation at 37°C to up to 12,000 nmol/mg protein. However, presence of a magnetic field also increased the amounts of iron that attached to the cells during incubation with Fe-NP at 4°C. These results suggest that the presence of an external magnetic field promotes in cultured astrocytes both the binding of Fe-NP to the cell membrane and the internalization of Fe-NP.

Magnetic iron oxide nanoparticles (IONPs) have been used for a variety of neurobiological applications, although little is yet known as to the fate of such particles in brain cells. To address these questions, we have exposed oligodendroglial OLN-93 cells to dimercaptosuccinate-coated IONPs. Treatment of the cells strongly increased the specific cellular iron content proportional to the IONP concentrations applied (0-1000 μM total iron as IONPs) up to 300-fold, but did not cause any acute cytotoxicity or induce oxidative stress. To investigate the potential of OLN-93 cells to liberate iron from the accumulated IONPs, we have studied the upregulation of the iron storage protein ferritin and the cell proliferation as cellular processes that depend on the availability of low-molecular-weight iron. The presence of IONPs caused a concentration-dependent increase in the amount of cellular ferritin and partially bypassed the inhibition of cell proliferation by the iron chelator deferoxamine. These data demonstrate that viable OLN-93 cells efficiently take up IONPs and suggest that these cells are able to use iron liberated from accumulated IONPs for their metabolism.

The oligodendroglial cell line OLN-93 was used as model system to investigate the consequences of iron deprivation or iron excess on cell proliferation. Presence of ferric or ferrous iron chelators inhibited the proliferation of OLN-93 cells in a time and concentration dependent manner, while the application of a molar excess of ferric ammonium citrate (FAC) prevented the inhibition of proliferation by the chelator deferoxamine. Proliferation of OLN-93 cells was not affected by incubation with 300 microM iron that was applied in the form of FAC, FeCl(2), ferrous ammonium sulfate or iron oxide nanoparticles, although the cells efficiently accumulated iron during exposure to each of these iron sources. The highest specific iron content was observed for cells that were exposed to the nanoparticles. These data demonstrate that the proliferation of OLN-93 cells depends strongly on the availability of iron and that these cells efficiently accumulate iron from various extracellular iron sources.

Despite having the highest theoretical specific capacity (3579 mAh/g), silicon has been known to undergo massive anisotropic volume expansion (~280%), and consequently, causing the fracture of the particles and loss of the specific capacity upon further cycling. Germanium has been reported to undergo isotropic expansion and observed in the in-situ studies to sustain lithiation induced fracture up to the particle size of ~680 nm. In this work, solid solution of Si and Ge of various compositions were synthesized. The formation of a single phase solid solution was confirmed by the X-ray diffraction and the electrode morphology were studied using Scanning electron microscopy. The solid solution of equimolar Si and Ge (Si0.5Ge0.5) displayed excellent electrochemical performance both in the cyclic stability as well as the total specific capacity.

Magnetic iron oxide nanoparticles (Fe-NP) are currently considered for various diagnostic and therapeutic applications in the brain. However, little is known on the accumulation and biocompatibility of such particles in brain cells. We have synthesized and characterized dimercaptosuccinic acid (DMSA) coated Fe-NP and have investigated their uptake by cultured brain astrocytes. DMSA-coated Fe-NP that were dispersed in physiological medium had an average hydrodynamic diameter of about 60 nm. Incubation of cultured astrocytes with these Fe-NP caused a time- and concentration-dependent accumulation of cellular iron, but did not lead within 6 h to any cell toxicity. After 4 h of incubation with 100–4000 µM iron supplied as Fe-NP, the cellular iron content reached levels between 200 and 2000 nmol mg − 1 protein. The cellular iron content after exposure of astrocytes to Fe-NP at 4 °C was drastically lowered compared to cells that had been incubated at 37 °C. Electron microscopy revealed the presence of Fe-NP-containing vesicles in cells that were incubated with Fe-NP at 37 °C, but not in cells exposed to the nanoparticles at 4 °C. These data demonstrate that cultured astrocytes efficiently take up DMSA-coated Fe-NP in a process that appears to be saturable and strongly depends on the incubation temperature.

We introduce a novel in vitro rainbow trout intestinal barrier model and demonstrate its suitability for investigating nanoparticle transport across the intestinal epithelium. Rainbow trout (Oncorhynchus mykiss) intestinal cells (RTgutGC) were grown as monolayers on permeable supports leading to a two-compartment intestinal barrier model consisting of a polarized epithelium, dividing the system into an upper (apical) and a lower (basolateral) compartment, and thereby mimicking the intestinal lumen and the portal blood, respectively. The cells express the tight junction protein ZO-1 and build up a transepithelial electrical resistance comparable to the in vivo situation. Fluorescent polystyrene nanoparticles (PS-NPs; average hydrodynamic diameter: 73 ± 18 nm) were accumulated by RTgutGC cells in a time-, temperature- and concentration-dependent manner. Uptake of PS-NPs was confirmed using fluorescence microscopy. Cells formed an efficient barrier largely preventing the translocation of PS-NPs to the basolateral compartment. Taken together, these data demonstrate the suitability of the in vitro barrier model to study the effects of nanoparticles in fish intestinal epithelial cells., Environmental Science: Nano, 3 (2), ISSN:2051-8153, ISSN:2051-8161