Metal uptake and distribution in the zebrafish (Danio rerio) embryo: differences between nanoparticles and metal ions

Quantitative data on nanoparticle and cation uptake are compared in a compartment-specific way and distinct differences between metals were identified

Toxicity of Tungsten Carbide and Cobalt-Doped Tungsten Carbide Nanoparticles in Mammalian Cells in Vitro

BACKGROUND: Tungsten carbide nanoparticles are being explored for their use in the manufacture of hard metals. To develop nanoparticles for broad applications, potential risks to human health and the environment should be evaluated and taken into consideration. OBJECTIVE: We aimed to assess the toxicity of well-characterized tungsten carbide (WC) and cobalt-doped tungsten carbide (WC-Co) nanoparticle suspensions in an array of mammalian cells. METHODS: We examined acute toxicity of WC and of WC-Co (10% weight content Co) nanoparticles in different human cell lines (lung, skin, and colon) as well as in rat neuronal and glial cells (i.e., primary neuronal and astroglial cultures and the oligodendrocyte precursor cell line OLN-93). Furthermore, using electron microscopy, we assessed whether natioparticles can be taken up by living cells. We chose these in vitro systems in order to evaluate for potential toxicity of the nanoparticles in different mammalian organs (i.e., lung, skin, intestine, and brain). RESULTS: Chemical-physical characterization confirmed that WC as well as WC-Co natioparticles with a mean particle size of 145 nm form stable suspensions in serum-containing cell culture media. WC nanoparticles were not acutely toxic to the studied cell lines. However, cytotoxicity became apparent when particles were doped with Co. The most sensitive were astrocytes and colon epithelial cells. Cytotoxicity of WC-Co nanoparticles was higher than expected based on the ionic Co content of the particles. Analysis by electron microscopy demonstrated presence of WC nanoparticles within mammalian cells. CONCLUSIONS: Our findings demonstrate that doping of WC nanoparticles with Co markedly increases their cytotoxic effect and that the presence of WC-Co in particulate form is essential to elicit this combinatorial effect

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles

We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol. We find that the population-averaging methods of SAXS, CLS and UV-Vis have high measurement repeatability and reproducibility, with between-labs variability of 2.6%, 11% and 1.4% respectively. However, results may be significantly biased for reasons including inaccurate material properties whose values are used to compute the number concentration. Particle-counting method results are less reproducibile than population-averaging methods, with measured between-labs variability of 68% and 46% for PTA and spICP-MS respectively. This study provides the stakeholder community with important comparative data to underpin measurement reproducibility and method validation for number concentration of nanoparticles

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles

We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol. We find that the population-averaging methods of SAXS, CLS and UV-Vis have high measurement repeatability and reproducibility, with between-labs variability of 2.6%, 11% and 1.4% respectively. However, results may be significantly biased for reasons including inaccurate material properties whose values are used to compute the number concentration. Particle-counting method results are less reproducibile than population-averaging methods, with measured between-labs variability of 68% and 46% for PTA and spICP-MS respectively. This study provides the stakeholder community with important comparative data to underpin measurement reproducibility and method validation for number concentration of nanoparticles

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles

We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol. We find that the population-averaging methods of SAXS, CLS and UV-Vis have high measurement repeatability and reproducibility, with between-labs variability of 2.6%, 11% and 1.4% respectively. However, results may be significantly biased for reasons including inaccurate material properties whose values are used to compute the number concentration. Particle-counting method results are less reproducibile than population-averaging methods, with measured between-labs variability of 68% and 46% for PTA and spICP-MS respectively. This study provides the stakeholder community with important comparative data to underpin measurement reproducibility and method validation for number concentration of nanoparticles

Report on SOP for dispersing nanomaterials in water and report on round robin test

This report describes a standard operation procedure for dispersion of nanomaterialsin liquids prior to toxicological or ecotoxicological testing. Mainfactors, who determine the state of agglomeration and aggregation ofENMs after dispersion are specific energy input, particle concentrationand fluid composition. The method was validated in two round robin tests,where two typical nanomaterials (a nanopowder and a nanodispersion)were investigated. One main result arising out of the data comparison wasthat only those participants, who were able to follow the instructions in theSOPs completely, received similar results regarding particle size and zetapotential. The SOP is easy to adapt for other types of nanomaterials. Theresults provide the standardization process and were presented at DINworking group

Imitating the weathering of microplastics in the marine environment

The existence of microplastic particles (polymer particles < 5 mm) in our environment has already been proven by several studies. It is known that the interactions between particles, meteorological (sun radiation [ultraviolet light, UV] and air temperature), and marine effects (water temperature, salinity and turbulences) lead to alterations in physical-chemical properties of plastic products or briefly to their degradation and fragmentation. By understanding the individual steps of the weathering process and the respective consequences for material properties (size, shape, density, crystallinity and surface properties), it is possible to predict the distribution, behavior and interactions of the particles in the environment and finally to assess their risk towards nature. The aim of this work is to mimic the weathering of microplastics in the marine environment under laboratory conditions and to evaluate its influence on material properties. This study is focusing on abiotic weathering processes including UV radiation and mechanical stress. Important data for weathering processes includes the initial state of microplastics, the energy source and input during weathering, and the state of microplastics after weathering. As model polymers, two materials are used, which differ in their chemical structure and density. It is expected that the weathering process of the materials depends on these properties

Wettability after Artificial and Natural Weathering of Polyethylene Terephthalate

The weathering of plastics is always accompanied by a change in surface properties, especially wettability in the case of water. For plastics weathering in an aquatic environment, wettability plays an important role in transport, sedimentation, and dispersion in the water body. To quantify wettability, contact angle measurement is a fast and convenient method that requires little experimental effort. This technique was used with the aim of systematically discussing how measured values of contact angles can contribute to the assessment of the weathering state. Using polyethylene terephthalate (PET), wetting was analyzed on samples from artificial weathering and from controlled, natural weathering. Surface analytical methods were used (Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), ultraviolet and visible light spectroscopy (UV/VIS)) to analyze the parameters affecting the contact angle: (i) chemical bond breaking and formation, (ii) eco-corona formation and biofilm growth, and (iii) change in surface structure and roughness. It was found that wettability with water increased during weathering in all cases. The reasons for this varied and depended on the method of weathering. The improved wettability during artificial weathering was due to changes in the polymer surface chemistry. In natural weathering, however, the formation of eco-corona and biofilm was responsible for the changes

Transport of carbon colloid supported nanoscale zero-valent iron in saturated porous media

Injection of nanoscale zero-valent iron (nZVI) has recently gained great interest as emerging technology for in-situ remediation of chlorinated organic compounds from groundwater systems. Zero-valent iron (ZVI) is able to reduce organic compounds and to render it to less harmful substances. The use of nanoscale particles instead of granular or microscale particles can increase dechlorination rates by orders of magnitude due to its high surface area. However, classical nZVI appears to be hampered in its environmental application by its limited mobility. One approach is colloid supported transport of nZVI, where the nZVI gets transported by a mobile colloid. In this study transport properties of activated carbon colloid supported nZVI (c-nZVI; d50 = 2.4 μm) are investigated in column tests using columns of 40 cm length, which were filled with porous media. A suspension was pumped through the column under different physicochemical conditions (addition of a polyanionic stabilizer and changes in pH and ionic strength). Highest observed breakthrough was 62% of the injected concentration in glass beads with addition of stabilizer. Addition of mono- and bivalent salt, e.g. more than 0.5 mM/L CaCl2, can decrease mobility and changes in pH to values below six can inhibit mobility at all. Measurements of colloid sizes and zeta potentials show changes in the mean particle size by a factor of ten and an increase of zeta potential from − 62 mV to − 80 mV during the transport experiment. However, results suggest potential applicability of c-nZVI under field conditions

Microstructural characteristics and performances of Cr2O3 and Cr2O3-15%TiO2 S-HVOF coatings obtained from water-based suspensions

Cr2O3-based coatings offer high hardness, excellent sliding wear performance, and corrosion resistance. Therefore, they are widely applied in the paper industry, as well as for pumps and mechanical sealing systems. Compared to the conventional spray processes, the technology of suspension-HVOF spraying (S-HVOF) allows the production of dense, finely structured coatings with smoother surfaces and improved mechanical properties by using submicron-scaled raw materials. This work investigates the microstructure and performances of Cr2O3 and Cr2O3-15%TiO2 coatings obtained by S-HVOF starting from water-based suspensions. For the development of the suspensions with binary composition, two routes were used to produce ready-to-spray suspensions: (a) mixture of two stable suspensions in the desired ratio, and (b) dispersion of an appropriate alloyed material in the solvent. In order to evaluate the potential of suspension spraying over the conventional APS and HVOF processes, the mechanical properties, corrosion, and sliding wear resistances of the S-HVOF coatings were compared with those of the coatings produced from feedstock spray powders. From the experimental results, it was observed that, in most of the cases, the suspension-sprayed coatings showed denser microstructures, enhanced mechanical properties, wear resistance, and superior corrosion performances