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There are significant differences in toxicity of PM components and cellular responses that can be linked to adverse health effects. Soot and copper oxide induced toxicity, reduced metabolic activity, increased ROS and altered immune response. Increased ROS generation and mitochondrial dysfunctions are well known features in COPD pathology. Toxicity of individual airborne particles can be used to better understand adverse health effects and improve air quality guidelines.
Flame retardants (FR) are inevitable additives to many plastics. Halogenated organics are effective FRs but are controversially discussed due to the release of toxic gases during a fire or their persistence if landfilled. Phosphorus-containing compounds are effective alternatives to halogenated FRs and have potential lower toxicity and degradability. In addition, nitrogencontaining additives were reported to induce synergistic effects with phosphorus-based FRs. However, no systematic study of the gradual variation on a single phosphorus FR containing both P−O and P−N moieties and their comparison to the respective blends of phosphates and phosphoramides was reported. This study developed general design principles for P−O- and P−N-based FRs and will help to design effective FRs for various polymers. We synthesized a library of phosphorus FRs that only differ in their P-binding pattern from each other and studied their decomposition mechanism in epoxy resins. Systematic control over the decomposition pathways of phosphate (PO(OR)3), phosphoramidate (PO(OR)2(NHR)), phosphorodiamidate (PO(OR)(NHR)2), phosphoramide (PO(NHR)3), and their blends was identified, for example, by reducing cis-elimination and the formation of P−N-rich char with increasing nitrogen content in the P-binding sphere. Our FR epoxy resins can compete with commercial FRs in most cases, but we proved that the blending of esters and amides outperformed the single molecule amidates/diamidates due to distinctively different decomposition mechanisms acting synergistically when blended.
The overall interest in nanotoxicity, triggered by the increasing use of nanomaterials in the material and life sciences, and the synthesis of an ever increasing number of new functional nanoparticles calls for standardized test procedures1,2 and for efficient approaches to screen the potential genotoxicity of these materials. Aiming at the development of fast and easy to use, automated microscopic methods for the determination of the genotoxicity of different types of nanoparticles, we assess the potential of the fluorometric γH2AX assay for this purpose. This assay, which can be run on an automated microscopic detection system, relies on the detection of DNA double strand breaks as a sign for genotoxicity3. Here, we provide first results obtained with broadly used nanomaterials like CdSe/CdS and InP/ZnS quantum dots as well as iron oxide, gold, and polymer particles of different surface chemistry with previously tested colloidal stability and different cell lines like Hep-2 and 8E11 cells, which reveal a dependence of the genotoxicity on the chemical composition as well as the surface chemistry of these nanomaterials. These studies will be also used to establish nanomaterials as positive and negative genotoxicity controls or standards for assay performance validation for users of this fluorometric genotoxicity assay. In the future, after proper validation, this microscopic platform technology will be expanded to other typical toxicity assays.
SETNanoMetro, a European Seventh Framework project, seeks to develop standard synthetic routes and metrological characterisation methods for the development and production of TiO2 nanoparticles and nano-sized coatings with highly-defined, homogeneous and reproducible characteristics. These materials are being tested for their potential in selected technological applications, including as biomaterials, specifically as coatings on dental or orthopaedic metallic prostheses. This study aimed to assess how variations in nano-scale morphology and phase composition of TiO2 coatings affect their biocompatibility in vitro.
Pulsed DC magnetron sputtering was used to deposit a layer of Ti metal followed by a layer of TiO¬2 on standard glass microscope slides. The substrate bias voltage was varied during deposition to control the morphology and phase composition of the TiO2 layers. In order of increasing substrate bias voltage, the phase compositions of the TiO2 layers were: predominantly anatase, mixed anatase/rutile, and predominantly rutile, as confirmed by XRD. Examination of the coating cross-sections by SEM revealed feather-like columnar structures in the thin (950 nm thick) and thick (1550 nm thick) anatase coatings and in the mixed anatase/rutile coating (900 nm thick). In the rutile coating (730 nm thick), the columns were denser and had largely lost their feather-like structure. Top-view SEM showed square-pyramidal morphology of the columns in the anatase coatings, with columns generally 100 nm or smaller in size (thin coating) or up to 200 nm across (thick coating). In the mixed anatase/rutile coating, the top-view showed less regular columnar morphology with more elongated columns (up to approx. 100 nm by 200 nm). In the rutile coating, the top-view showed a less ordered, pebble-like morphology.
MG-63 human osteoblast-like cells and RAW 264.7 murine macrophage cells were cultured on the TiO2-coated substrates for 24 or 72 h before quantification of cell proliferation using the WST-1 cell proliferation assay. A toxic response was defined as a reduction in cell viability of greater than 30%. After 24 h culture, proliferation of MG-63 cells was significantly greater than the control (p < 0.05) on the thin anatase and mixed anatase/rutile coatings. After 72 h of culture no significant difference to the control was observed. For RAW 264.7 cells, proliferation was non-significantly decreased compared to the control on all coatings except the rutile coating after 24 h. After 72 h, RAW 264.7 proliferation was significantly decreased (p < 0.01) to 68% and 61% of the control for the thick and thin anatase coatings, respectively, indicating a toxic response. The results indicate that nano-sized TiO2 coatings show different biocompatibility to different test cell types, with a dependence upon coating phase composition and morphology.
Tracking silver nanoparticles: ultra-small silver refunctionalizable with fluorescent biopolymers
(2016)
We report on the synthesis of ultra-small silver nanoparticles and their quantitative characterization by small-angle X-ray scattering. The size distribution was derived by utilizing a Monte-Carlo data evaluation procedure reported by Pauw et al. Mean volume-weighted sizes are 3 nm with a size distribution width of 18 %. The particles should be used as reference materials for comparison of the result of different analytical methods among which are field-flow fractionation (FFF), dynamic light scattering (DLS), nanoparticle tracking analysis (NTA) and electron microscopy (EM). In addition further use of the particles is foreseen for comparison of studies on the toxicology of nanoparticles. Therefore the silver nanoparticles are transfunctionalized with fluorescent marked albumin (BSA-FITC) and also thoroughly characterized. With this it is possible to track silver nanoparticles and their behavior in interaction with cells.
Cellular effects of Al-, Ti- and Zn-containing nanomaterials on intestinal cell lines in vitro
(2016)
Aluminium-, titanium- and zinc-containing chemicals are highly abundant in food, food contact materials and consumer products. Physical and chemical conversion might lead to a certain amount of nanoscaled particles that can be taken up by the gastrointestinal tract. Nanospecific effects such as higher reactivity, increased surface or altered uptake can increase hazardous potential for human health. The aim of this study as part of the european SolNanoTOX project is to characterize toxicological effects of Al-, Zn- and Ti-containing nanomaterials on intestinal cell lines.
While toxicological potential of zinc species has been well studied, little is known about the effects of aluminium- and titanium-species. We have performed toxicological experiments on the human intestinal cell line Caco-2 for numerous endpoints: Cellular ATP and glutathione levels, apoptosis, necrosis, vesicular uptake, oxidative stress, growth rate and cell cycle modification. While zinc-containing controls showed toxic responses, our utilized aluminium- (elementary Al, γ-Al2O3) and titanium-species (TiO2, rutile) did not. Nevertheless, we detected some differences between both different aluminium nanoparticle species and aluminium ions with regard to cell viability. We also provide strong evidence for particle-specific uptake of aluminium and titanium in the intestinal cell line Caco-2.
In summary, among the different tested endpoints, Al- and Ti-containing nanomaterials did not show any toxicity in intestinal cell lines in vitro. Nevertheless, this absence of effect was not due to an absence of exposure, since particle-specific uptake was reported. Metal particle uptake over a long time might therefore be relevant for risk assessment of aluminium- and titanium-containing food products.
Vehicle fires in tunnels can have catastrophic consequences for the road users, the property and traffic inffastructure. To support an evacuation planning, this study simulates the fire smoke toxicity and the smoke layer of a vehicle fire in a full-size test tunnel. The three dimensional prediction of the fire smoke toxicity in the test tunnel is realized by implementing the Fractional Effective Dose and the Fractional Summation concept in a CFD environment. The developed model facilitates to calculate fire scenarios for various types of tunnels and to quantify the hazard e.g. during an evacuation scenario.
The influence of fire accelerants on the fire behavior during living room fires was experimentally investigated by performing 5 different room fire scenarios. During the tests flre-technological quantities were determined as well as chemical-analytical studies were carried out. The focus was on the detection of smoke gases and the proof of used fire accelerants. The evaluation of traceable fire accelerants and the reconstruction of the fire development are based on a precise Chemical analysis of the combustion products.
In this work an innovative methodology was developed to combine available analyticai techniques to draw conclusions from solid, liquid and gaseous fire residues about the fire process. Each ofthe fire rooms was equipped with the same living room inventory. The location and amount of fire accelerant (a mixture of diesel/gasoline) differed in 4 of 5 tests. Orte room fire experiment was carried out without fire accelerant.
The following fire technological characteristics were determined during the room fire experiments: mass loss (of the complete room), temperatures (at several locations in the room), heat release and smoke gas emission (measured at three different locations: in the chimney, in the fire room and at the door opening).
While the smoke gases were analysed by using Fourier Transform Infrared spectroscopy, the fire residues and swipe samples (particles) were examined by Headspace-Solid Phase Microextraction-
Gaschromatography-Mass spectrometry. These procedures make it possible to detect low concentrations of volatile components of the fire accelerants. The Chemical analyticai results of the fire accelerant detection are presented.