TY  - JOUR
AB  - The shredding of waste of electrical and electronic equipment (WEEE) and other products, incorporated with nanomaterials, can lead to a substantial release of nanomaterials. Considering the uncertainty, complexity, and scarcity of experimental data on release, we present the development of a Bayesian belief network (BBN) model. This baseline model aims to give a first prediction of the release of nanomaterials (excluding nanofibers) during their mechanical shredding. With a focus on the description of the model development methodology, we characterize nanomaterial release in terms of number, size, mass, and composition of released particles. Through a sensitivity analysis of the model, we find the material-specific parameters like affinity of nanomaterials to the matrix of the composite and their state of dispersion inside the matrix to reduce the nanomaterial release up to 50%. The shredder-specific parameters like number of shafts in a shredder and input and output size of the material for shredding could minimize it up to 98%. The comparison with two experimental test cases shows promising outcome on the prediction capacity of the model. As additional experimental data on nanomaterial release becomes available, the model is able to further adapt and update risk forecasts. When adapting the model with additional expert beliefs, experts should be selected using criteria, e.g., substantial contribution to nanomaterial and/or particulate matter release-related scientific literature, the capacity and willingness to contribute to further development of the BBN model, and openness to accepting deviating opinions.
AU  - Shandilya, N.*
AU  - Ligthart, T.*
AU  - van Voorde, I.*
AU  - Stahlmecke, B.*
AU  - Clavaguera, S.*
AU  - Philippot, C.*
AU  - Ding, Y.
AU  - Goede, H.*
C1  - 52974
C2  - 44396
CY  - Dordrecht
TI  - A nanomaterial release model for waste shredding using a Bayesian belief network.
JO  - J. Nanopart. Res.
VL  - 20
IS  - 2
PB  - Springer
PY  - 2018
SN  - 1388-0764
ER  - 

TY  - JOUR
AB  - The intensive use of nano-sized particles in many different applications necessitates studies on their risk assessment as there are still open questions on their safe handling and utilization. For reliable risk assessment, the interaction of nanoparticles (NP) with biological systems after various routes of exposure needs to be investigated using well-characterized NP. We report here on the generation of gold-NP (Au-NP) aerosols for inhalation studies with the spark ignition technique, and their characterization in terms of chemical composition, physical structure, morphology, and specific surface area, and on interaction with lung tissues and lung cells after 1 h inhalation by mice. The originally generated agglomerated Au-NP were converted into compact spherical Au-NP by thermal annealing at 600 degrees C, providing particles of similar mass, but different size and specific surface area. Since there are currently no translocation data available on inhaled Au-NP in the 10-50 nm diameter range, the emphasis was to generate NP as small as 20 nm for inhalation in rodents. For anticipated in vivo systemic translocation and dosimetry analyses, radiolabeled Au-NP were created by proton irradiating the gold electrodes of the spark generator, thus forming gamma ray emitting Au-195 with 186 days half-life, allowing long-term biokinetic studies. The dissolution rate of Au-195 from the NP was below detection limits. The highly concentrated, polydisperse Au-NP aerosol (1-2 x 10(7) NP/cm(3)) proved to be constant over several hours in terms of its count median mobility diameter, its geometric standard deviation and number concentration. After collection on filters particles can be re-suspended and used for instillation or ingestion studies.
AU  - Möller, W.
AU  - Gibson, N.*
AU  - Geiser, M.*
AU  - Pokrehl, S.*
AU  - Wenk, A.
AU  - Takenaka, S.
AU  - Schmid, O.
AU  - Bulgheroni, A.*
AU  - Simonelli, F.*
AU  - Kozempel, J.*
AU  - Holzwarth, U.*
AU  - Wigge, C.*
AU  - Eigeldinger-Berthou, S.*
AU  - Mädler, L.*
AU  - Kreyling, W.G.
C1  - 23681
C2  - 31230
TI  - Gold nanoparticle aerosols for rodent inhalation and translocation studies.
JO  - J. Nanopart. Res.
VL  - 15
IS  - 4
PB  - Springer
PY  - 2013
SN  - 1388-0764
ER  - 

TY  - JOUR
AB  - The intensive use of nano-sized titanium dioxide (TiO2) particles in many different applications necessitates studies on their risk assessment as there are still open questions on their safe handling and utilization. For reliable risk assessment, the interaction of TiO2 nanoparticles (NP) with biological systems ideally needs to be investigated using physico-chemically uniform and well-characterized NP. In this article, we describe the reproducible production of TiO2 NP aerosols using spark ignition technology. Because currently no data are available on inhaled NP in the 10–50 nm diameter range, the emphasis was to generate NP as small as 20 nm for inhalation studies in rodents. For anticipated in vivo dosimetry analyses, TiO2 NP were radiolabeled with 48V by proton irradiation of the titanium electrodes of the spark generator. The dissolution rate of the 48V label was about 1% within the first day. The highly concentrated, polydisperse TiO2 NP aerosol (3–6 × 106 cm−3) proved to be constant over several hours in terms of its count median mobility diameter, its geometric standard deviation, and number concentration. Extensive characterization of NP chemical composition, physical structure, morphology, and specific surface area was performed. The originally generated amorphous TiO2 NP were converted into crystalline anatase TiO2 NP by thermal annealing at 950 °C. Both crystalline and amorphous 20-nm TiO2 NP were chain agglomerated/aggregated, consisting of primary particles in the range of 5 nm. Disintegration of the deposited TiO2 NP in lung tissue was not detectable within 24 h.
AU  - Kreyling, W.G.
AU  - Biswas, P.*
AU  - Messing, M.E.*
AU  - Gibson, N.*
AU  - Geiser, M.*
AU  - Wenk, A.
AU  - Sahu, M.*
AU  - Deppert, K.*
AU  - Cydzik, I.
AU  - Wigge, C.*
AU  - Schmid, O.
AU  - Semmler-Behnke, M.
C1  - 4201
C2  - 27755
CY  - Berlin [u.a.]
SP  - 511-524
TI  - Generation and characterization of stable, highly concentrated titanium dioxide nanoparticle aerosols for rodent inhalation studies.
JO  - J. Nanopart. Res.
VL  - 13
IS  - 2
PB  - Springer
PY  - 2011
SN  - 1388-0764
ER  - 

TY  - JOUR
AB  - The International Alliance for NanoEHS Harmonization (IANH) organises interlaboratory comparisons of methods used to study the potential biological impacts of nanomaterials. The aim of IANH is to identify and reduce or remove sources of variability and irreproducibility in existing protocols. Here, we present results of the first IANH round robin studies into methods to assess the size and surface charge of suspended nanoparticles. The test materials used (suspensions of gold, silica, polystyrene, and ceria nanoparticles, with [primary] particles sizes between 10 nm and 80 nm) were first analysed in repeatability conditions to assess the possible contribution of between-sample heterogeneity to the between-laboratory variability. Reproducibility of the selected methods was investigated in an interlaboratory comparison between ten different laboratories in the USA and Europe. Robust statistical analysis was used to evaluate within- and between-laboratory variability. It is shown that, if detailed shipping, measurement, and reporting protocols are followed, measurement of the hydrodynamic particle diameter of nanoparticles in predispersed monomodal suspensions using the dynamic light scattering method is reproducible. On the other hand, measurements of more polydisperse suspensions of nanoparticle aggregates or agglomerates were not reproducible between laboratories. Ultrasonication, which is commonly used to prepare dispersions before cell exposures, was observed to further increase variability. The variability of the zeta potential values, which were also measured, indicates the need to define better surface charge test protocols and to identify sources of variability.
AU  - Roebben, G.*
AU  - Ramirez-Garcia, S.*
AU  - Hackley, V.A.*
AU  - Roesslein, M.*
AU  - Klaessig, F.*
AU  - Kestens, V.*
AU  - Lynch, I.*
AU  - Garner, C.M.*
AU  - Rawle, A.*
AU  - Elder, A.*
AU  - Colvin, V.L.*
AU  - Kreyling, W.G.
AU  - Krug, H.F.*
AU  - Lewicka, Z.A.*
AU  - McNeil, S.*
AU  - Nel, A.*
AU  - Patri, A.*
AU  - Wick, P.*
AU  - Wiesner, M.*
AU  - Xia, T.*
AU  - Oberdörster, G.*
AU  - Dawson, K.A.*
C1  - 6344
C2  - 28681
SP  - 2675-2687
TI  - Interlaboratory comparison of size and surface charge measurements on nanoparticles prior to biological impact assessment.
JO  - J. Nanopart. Res.
VL  - 13
IS  - 7
PB  - Springer
PY  - 2011
SN  - 1388-0764
ER  - 

TY  - JOUR
AB  - Industrially manufactured titanium dioxide nanoparticles have been successfully radiolabelled with V-48 by irradiation with a cyclotron-generated proton beam. Centrifugation tests showed that the V-48 radiolabels were stably bound within the nanoparticle structure in an aqueous medium, while X-ray diffraction indicated that no major structural modifications to the nanoparticles resulted from the proton irradiation. In vitro tests of the uptake of cold and radiolabelled nanoparticles using the human cell line Calu-3 showed no significant difference in the uptake between both batches of nanoparticles. The uptake was quantified by Inductively Coupled Plasma Mass Spectrometry and high resolution gamma-ray spectrometry for cold and radiolabelled nanoparticles, respectively. These preliminary results indicate that alterations to the nanoparticles' properties introduced by proton bombardment can be controlled to a sufficient extent that their further use as radiotracers for biological investigations can be envisaged and elaborated.
AU  - Abbas, K.*
AU  - Cydzik, I.*
AU  - Del Torchio, R.*
AU  - Farina, M.*
AU  - Forti, E.*
AU  - Gibson, N.*
AU  - Holzwarth, U.*
AU  - Simonelli, F.*
AU  - Kreyling, W.G.
C1  - 5283
C2  - 27744
CY  - Berlin [u.a.]
SP  - 2435-2443
TI  - Radiolabelling of TiO₂ nanoparticles for radiotracer studies.
JO  - J. Nanopart. Res.
VL  - 12
IS  - 7
PB  - Springer
PY  - 2010
SN  - 1388-0764
ER  - 

TY  - JOUR
AB  - Several studies have reported laser printers as significant sources of nanosized particles (<0.1 μm). Laser printers are used occupationally in office environments and by consumers in their homes. The current work combines existing epidemiological and toxicological evidence on particle-related health effects, measuring doses as mass, particle number and surface area, to estimate and compare the potential risks in occupational and consumer exposure scenarios related to the use of laser printers. The daily uptake of laser printer particles was estimated based on measured particle size distributions and lung deposition modelling. The obtained daily uptakes (particle mass 0.15–0.44 μg d−1; particle number 1.1–3.1 × 109 d−1) were estimated to correspond to 4–13 (mass) or 12–34 (number) deaths per million persons exposed on the basis of epidemiological risk estimates for ambient particles. These risks are higher than the generally used definition of acceptable risk of 1 × 10−6, but substantially lower than the estimated risks due to ambient particles. Toxicological studies on ambient particles revealed consistent values for lowest observed effect levels (LOELs) which were converted into equivalent daily uptakes using allometric scaling. These LOEL uptakes were by a factor of about 330–1,000 (mass) and 1,000–2,500 (particle surface area) higher than estimated uptakes from printers. This toxicological assessment would indicate no significant health risks due to printer particles. Finally, our study suggests that particle number (not mass) and mass (not surface area) are the most conservative risk metrics for the epidemiological and toxicological risks presented here, respectively.
AU  - Hänninen, O.O.
AU  - Brüske, I.
AU  - Loh, M.*
AU  - Stöger, T.
AU  - Kreyling, W.G.
AU  - Schmid, O.
AU  - Peters, A.
C1  - 1416
C2  - 26707
SP  - 91-99
TI  - Occupational and consumer risk estimates for nanoparticles emitted by laser printers.
JO  - J. Nanopart. Res.
VL  - 12
IS  - 1
PY  - 2010
SN  - 1388-0764
ER  - 

TY  - JOUR
AB  - Spark generated carbon and iridium nanoparticles were characterised by their electrical-mobility diameter D and by the mass of particulate matter collected in parallel on filter. The particles exhibited slightly skewed lognormal size distributions with mean mobility diameters between 18 and 74 nm. The masses calculated from the measured distributions under the assumption that the particles were spherical (diameter D) and of bulk mass density turned out to be much higher than the gravimetric mass, by factors between 8 and as high as 340. This very pronounced difference initiated a search for an improved relation between particle size and mass. Data analysis suggested that the mass increases linearly with increasing D. Hence the measured distributions were evaluated under the assumption that the spark generated matter was composed of spherical primary nanoparticles of mean diameter d, aggregated in the form of chains of joint length beta D, with beta > 1. Using reasonable values of beta between 2 and 4, the mean diameter of carbon primary particles turned out to be 10 +/- 1.8 nm, in excellent agreement with size data recently obtained by transmission electron microscopy (TEM). The primary iridium particles were found to be distinctly smaller, with diameters between 3.5 +/- 0.6 nm and 5.4 +/- 0.9 nm. The comparatively small uncertainty is due to the fact that the primary-particle diameter is proportional to the square root of beta. The calculated volume specific surface areas range between 500 and 1700 m(2)/cm(3). These numbers are close to the 'active' surface areas previously measured by the BET method. The good agreement with TEM and BET data suggests that the novel approach of nanoparticle characterisation is meaningful. Accordingly, the number concentrations of all individual primary particles rather than the concentrations measured by the mobility analyser should be considered the correct dose metric in studies on animal exposure to spark generated nanoparticles. The evaluated data imply that the numbers quoted in the literature must be enlarged by factors ranging between about 10 and a maximum as high as 80.
AU  - Wittmaack, K.
C1  - 4027
C2  - 25051
SP  - 191-200
TI  - Deriving the mean primary-particle diameter and related quantities from the size distribution and the gravimetric mass of spark generated nanoparticles.
JO  - J. Nanopart. Res.
VL  - 9
IS  - 2
PB  - Kluwer
PY  - 2007
SN  - 1388-0764
ER  - 

TY  - JOUR
AU  - Kreyling, W.G.
AU  - Semmler-Behnke, M.
AU  - Möller, W.
C1  - 4493
C2  - 24137
SP  - 543-562
TI  - Health implications of nanoparticles.
JO  - J. Nanopart. Res.
VL  - 8
PY  - 2006
SN  - 1388-0764
ER  -