Time filter

Source Type

Copenhagen, Denmark

Ema M.,Japan National Institute of Advanced Industrial Science and Technology | Hougaard K.S.,Danish Center for Nanosafety | Kishimoto A.,Japan National Institute of Advanced Industrial Science and Technology | Honda K.,Japan National Institute of Advanced Industrial Science and Technology
Nanotoxicology | Year: 2015

We summarized the findings of reproductive and developmental toxicity studies on carbon-based nanomaterials (CNMs). Placental transfer of fullerenes in rats and single-walled (SW) and multi-walled (MW) CNTs in mice was shown after intravenous injection. SWCNTs appeared to be embryolethal and teratogenic in mice when given by intravenous injection and induced death and growth retardation in chicken embryos. In mice-administered MWCNTs, fetal malformations after intravenous and intraperitoneal injections and intratracheal instillation, fetal loss after intravenous injection, behavioral changes in offspring after intraperitoneal injection, and a delay in the delivery of the first litter after intratracheal instillation were reported. Oral gavage of MWCNTs had no developmental toxicity in mice and rats. MWCNTs produced morphological defects, developmental arrest, and death in zebrafish embryos. Intratracheal instillation of carbon black (CB) induced testicular toxicity in adult mice. Maternal airway exposure to CB in gestation had testicular toxicity and altered postnatal behavior, renal development, immune and genotoxic responses, and brain morphology in mouse offspring. Nanodiamonds and graphite nanoparticles inhibited vasculogenesis and/or angiogenesis in chicken embryos. Graphene oxide (GO) induced malformations in zebrafish embryos. Intravenous injection of reduced GO during late gestation caused maternal death and abortion in mice. Oral administration of GO during lactation caused growth retardation of offspring. Overall, the available data provide initial information on the potential reproductive and developmental toxicity of CNMs. However, confirmatory studies using well-characterized CNMs, state-of-the-art study protocol and appropriate route of exposure, are required to clarify the findings and provide information suitable for risk assessment. © 2015 Taylor & Francis. Source

Nymark P.,Maastricht University | Alstrup J.K.,Danish Center for Nanosafety | Suhonen S.,Finnish Institute of Occupational Health | Kembouche Y.,Danish Center for Nanosafety | And 8 more authors.
Particle and Fibre Toxicology | Year: 2014

Background: Certain multi-walled carbon nanotubes (MWCNTs) have been shown to elicit asbestos-like toxicological effects. To reduce needs for risk assessment it has been suggested that the physicochemical characteristics or reactivity of nanomaterials could be used to predict their hazard. Fibre-shape and ability to generate reactive oxygen species (ROS) are important indicators of high hazard materials. Asbestos is a known ROS generator, while MWCNTs may either produce or scavenge ROS. However, certain biomolecules, such as albumin - used as dispersants in nanomaterial preparation for toxicological testing in vivo and in vitro - may reduce the surface reactivity of nanomaterials.Methods: Here, we investigated the effect of bovine serum albumin (BSA) and cell culture medium with and without BEAS 2B cells on radical formation/scavenging by five MWCNTs, Printex 90 carbon black, crocidolite asbestos, and glass wool, using electron spin resonance (ESR) spectroscopy and linked this to cytotoxic effects measured by trypan blue exclusion assay. In addition, the materials were characterized in the exposure medium (e.g. for hydrodynamic size-distribution and sedimentation rate).Results: The test materials induced highly variable cytotoxic effects which could generally be related to the abundance and characteristics of agglomerates/aggregates and to the rate of sedimentation. All carbon nanomaterials were found to scavenge hydroxyl radicals (•OH) in at least one of the solutions tested. The effect of BSA was different among the materials. Two types of long, needle-like MWCNTs (average diameter >74 and 64.2 nm, average length 5.7 and 4.0 μm, respectively) induced, in addition to a scavenging effect, a dose-dependent formation of a unique, yet unidentified radical in both absence and presence of cells, which also coincided with cytotoxicity.Conclusions: Culture medium and BSA affects scavenging/production of •OH by MWCNTs, Printex 90 carbon black, asbestos and glass-wool. An unidentified radical is generated by two long, needle-like MWCNTs and these two CNTs were more cytotoxic than the other CNTs tested, suggesting that this radical could be related to the adverse effects of MWCNTs. © 2014 Nymark et al.; licensee BioMed Central Ltd. Source

Vranic S.,University Paris Diderot | Vranic S.,University of Manchester | Gosens I.,National Institute for Public Health and the Environment | Jacobsen N.R.,Danish Center for Nanosafety | And 9 more authors.
Archives of Toxicology | Year: 2016

Nanoparticles (NP) have a tendency to agglomerate after dispersion in physiological media, which can be prevented by the addition of serum. This may however result in modification of the toxic potential of particles due to the formation of protein corona. Our study aimed to analyze the role of serum that is added to improve the dispersion of 10 nm TiO2 NPs on in vitro and in vivo effects following the exposure via the respiratory route. We characterized NP size, surface charge, sedimentation rate, the presence of protein corona and the oxidant-generating capacity after NP dispersion in the presence/absence of serum. The effect of serum on NP internalization, cytotoxicity and pro-inflammatory responses was assessed in a human pulmonary cell line, NCI-H292. Serum in the dispersion medium led to a slower sedimentation, but an enhanced cellular uptake of TiO2 NPs. Despite this greater uptake, the pro-inflammatory response in NCI-H292 cells was lower after serum supplementation (used either as a dispersant or as a cell culture additive), which may be due to a reduced intrinsic oxidative potential of TiO2 NPs. Interestingly, serum could be added 2 h after the NP treatment without affecting the pro-inflammatory response. We also determined the acute pulmonary and hepatic toxicity in vivo 24 h after intratracheal instillation of TiO2 NPs in C57BL/6N mice. The use of serum resulted in an underestimation of the local acute inflammatory response in the lung, while a systemic response on glutathione reduction remained unaffected. In conclusion, serum as a dispersion agent for TiO2 NPs can lead to an underestimation of the acute pro-inflammatory response in vitro and in vivo. To avoid potential unwanted effects of dispersants and medium components, we recommend that the protocol of NM preparation should be thoroughly tested, and reflect as close as possible realistic exposure conditions. © 2016 Springer-Verlag Berlin Heidelberg Source

Jackson P.,Danish Center for Nanosafety | Kling K.,Danish Center for Nanosafety | Jensen K.A.,Danish Center for Nanosafety | Clausen P.A.,Danish Center for Nanosafety | And 5 more authors.
Environmental and Molecular Mutagenesis | Year: 2015

Carbon nanotubes vary greatly in physicochemical properties. We compared cytotoxic and genotoxic response to 15 multiwalled carbon nanotubes (MWCNT) with varying physicochemical properties to identify drivers of toxic responses. The studied MWCNT included OECD Working Party on Manufactured Nanomaterials (WPMN) (NM-401, NM-402, and NM-403), materials (NRCWE-026 and MWCNT-XNRI-7), and three sets of surface-modified MWCNT grouped by physical characteristics (thin, thick, and short I-III, respectively). Each Groups I-III included pristine, hydroxylated and carboxylated MWCNT. Group III also included an amino-functionalized MWCNT. The level of surface functionalization of the MWCNT was low. The level and type of elemental impurities of the MWCNT varied by <2% of the weight, with exceptions. Based on dynamic light scattering data, the MWCNT were well-dispersed in stock dispersion of nanopure water with 2% serum, but agglomerated and sedimented during exposure. FE1-Muta(TM) Mouse lung epithelial cells were exposed for 24 hr. The levels of DNA strand breaks (SB) were evaluated using the comet assay, a screening assay suitable for genotoxicity testing of nanomaterials. Exposure to MWCNT (12.5-200 μg/ml) did not induce significant cytotoxicity (viability above 92%). Cell proliferation was reduced in highest doses of some MWCNT after 24 hr, and was associated with generation of reactive oxygen species and high surface area. Increased levels of DNA SB were only observed for Group II consisting of MWCNT with large diameters and high Fe2O3 and Ni content. Significantly, increased levels of SB were only observed at 200 μg/ml of MWCNT-042. Overall, the MWCNT were not cytotoxic and weakly genotoxic after 24 hr exposure to doses up to 200 μg/ml. © 2014 Wiley Periodicals, Inc. Source

Kyjovska Z.O.,Danish Center for Nanosafety | Jacobsen N.R.,Danish Center for Nanosafety | Saber A.T.,Danish Center for Nanosafety | Bengtson S.,Danish Center for Nanosafety | And 4 more authors.
Environmental and Molecular Mutagenesis | Year: 2015

We previously observed genotoxic effects of carbon black nanoparticles at low doses relative to the Danish Occupational Exposure Limit (3.5 mg/m3). Furthermore, DNA damage occurred in broncho-alveolar lavage (BAL) cells in the absence of inflammation, indicating that inflammation is not required for the genotoxic effects of carbon black. In this study, we investigated inflammatory and acute phase response in addition to genotoxic effects occurring following exposure to nanoparticulate carbon black (NPCB) at even lower doses. C57BL/6JBomTac mice were examined 1, 3, and 28 days after a single instillation of 0.67, 2, 6, and 162 μg Printex 90 NPCB and vehicle. Cellular composition and protein concentration was evaluated in BAL fluid as markers of inflammatory response and cell damage. DNA strand breaks in BAL cells, lung, and liver tissue were assessed using the alkaline comet assay. The pulmonary acute phase response was analyzed by Saa3 mRNA real-time quantitative PCR. Instillation of the low doses of NPCB induced a slight neutrophil influx one day after exposure. Pulmonary exposure to small doses of NPCB caused an increase in DNA strand breaks in BAL cells and lung tissue measured using the comet assay. We interpret the increased DNA strand breaks occurring following these low exposure doses of NPCB as DNA damage caused by primary genotoxicity in the absence of substantial inflammation, cell damage, and acute phase response. © 2014 The Authors. Source

Discover hidden collaborations