| 1. |
- Arvidsson, Rickard, 1984, et al.
(författare)
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Environmental and health risks of nanorobots: an early review
- 2020
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Ingår i: Environmental Science: Nano. - : Royal Society of Chemistry (RSC). - 2051-8161 .- 2051-8153. ; 7:10, s. 2875-2886
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Tidskriftsartikel (refereegranskat)abstract
- Nanorobots for biomedical applications have experienced extensive research and rapid development during the last decade, up to a point where they can now deliver cargos to designated sites in organisms under laboratory conditions. Despite this development, research into nanorobot risks and discussions about potential regulation of nanorobots have so far been limited. This early review of risks related to nanorobots first provides a brief overview of the current state of the technology. The overview outlines three main types of nanorobots: helices, nanorods and DNA nanorobots. Several different designs exist for each of these categories. Second, early indications of potential hazards are reviewed and discussed. Two potential hazards are highlighted: (i) the use of hazardous materials and UV light in nanorobots, and (ii) the loss of propulsion/targeting control. Third, how current regulations are adapted to nanorobots is discussed. Current regulations for medical devices are clearly not adapted to nanorobots and it is even unclear which specific regulations might be applicable. In order to make the most of the use of nanorobots, we recommend they should be subject to broad, risk-related studies as well as dialogues with stakeholders and the public about the definition, purpose and controllability of nanorobot applications. A list of ten priority questions to be addressed in future risk-related studies of nanorobots is provided.
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| 2. |
- Baalousha, M., et al.
(författare)
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Modeling nanomaterial fate and uptake in the environment: current knowledge and future trends
- 2016
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Ingår i: Environmental Science-Nano. - : Royal Society of Chemistry (RSC). - 2051-8153 .- 2051-8161. ; 3:2, s. 323-345
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Tidskriftsartikel (refereegranskat)abstract
- Modeling the environmental fate of nanomaterials (NMs) and their uptake by cells and organisms in the environment is essential to underpin experimental research, develop overarching theories, improve our fundamental understanding of NM exposure and hazard, and thus enable risk assessment of NMs. Here, we critically review the state-of-the-art of the available models that can be applied/adapted to quantify/predict NM fate and uptake in aquatic and terrestrial systems and make recommendations regarding future directions for model development. Fate models have evolved from substance flow analysis models that lack nano-specific processes to more advanced mechanistic models that (at least partially) take nano-specific (typically non-equilibrium, dynamic) processes into account, with a focus on key fate processes such as agglomeration, sedimentation and dissolution. Similarly, NM uptake by organisms is driven by dynamic processes rather than by equilibrium partitioning. Hence, biokinetic models are more suited to model NM uptake, compared with the simple bio-accumulation factors used for organic compounds. Additionally, biokinetic models take speciation processes (e.g. particulate versus ionic uptake) into account, although identifying essential environment-specific processes to include in models remains a challenge. The models developed so far require parameterization, calibration and validation with available data, e.g. field data (if available), or experimental data (e.g. aquatic and terrestrial mesocosms), rather than extension to more complex and sophisticated models that include all possible transformation processes. Collaborative efforts between experimentalists and modelers to generate appropriate ground-truth data would advance the field most rapidly.
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| 3. |
- Bayat, Narges, et al.
(författare)
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Assessment of functionalized iron oxide nanoparticles in vitro : introduction to integrated nanoimpact index
- 2015
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Ingår i: Environmental Science: Nano. - : Royal Society of Chemistry (RSC). - 2051-8153 .- 2051-8161. ; 2:4, s. 380-394
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Tidskriftsartikel (refereegranskat)abstract
- Functionalization of super paramagnetic iron oxide NPs (SPIONs) with different coatings renders them with unique physicochemical properties that allow them to be used in a broad range of applications such as drug targeting and water purification. However, it is required to fill the gap between the promises of any new functionalized SPIONs and the effects of these coatings on the NPs safety. Nanotoxicology is offering diverse strategies to assess the effect of exposure to SPIONs in a case-by-case manner but an integrated nanoimpact scale has not been developed yet. We have implemented the classical integrated biological response (IBR) into an integrated nanoimpact index (INI) as an early warning scale of nano-impact based on a combination of toxicological end points such as cell proliferation, oxidative stress, apoptosis and genotoxicity. Here, the effect of SPIONs functionalized with tri-sodium citrate (TSC), polyethylenimine (PEI), aminopropyl-triethoxysilane (APTES) and Chitosan (chitosan) were assessed on human keratinocytes and endothelial cells. Our results show that endothelial cells were more sensitive to exposure than keratinocytes and the initial cell culture density modulated the toxicity. PEI-SPIONs had the strongest effects in both cell types while TSC-SPIONS were the most biocompatible. This study emphasizes not only the importance of surface coatings but also the cell type and the initial cell density on the selection of toxicity assays. The INI developed here could offer an initial rationale to choose either modifying SPIONs properties to reduce its nanoimpact or performing a complete risk assessment to define the risk boundaries.
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| 4. |
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| 5. |
- Bundschuh, Mirco
(författare)
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Distribution of engineered Ag nanoparticles in the aquatic-terrestrial transition zone: a long-term indoor floodplain mesocosm study
- 2021
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Ingår i: Environmental Science: Nano. - : Royal Society of Chemistry (RSC). - 2051-8153 .- 2051-8161. ; , s. 1771-1785
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Tidskriftsartikel (refereegranskat)abstract
- The fate of engineered nanoparticles in the aquatic-terrestrial transition zone is decisive for their effect in the environment. However, our knowledge on processes within this interface is rather low. Therefore, we used a floodplain stream mesocosm to enhance our understanding of the long-term distribution and biological effects of citrate-coated silver nanoparticles (Ag-NPs) in this ecosystem. Parallel to pulsed dosing of Ag-NPs, we observed fluctuating but successively increasing concentrations of aqueous Ag, 88-97% of which was categorized as particles. The remaining dissolved fraction was mainly complexed with natural organic matter (NOM). The major Ag fraction (50%) was associated with the uppermost sediment layer. The feeding activity of benthic amphipods was largely unaffected, which could be explained by the low Ag concentration and complexation of released Ag+ with NOM. According to our hypothesis, only a small nanoparticle fraction (6%) moved to the terrestrial area due to aquatic aging and enrichment of Ag-NPs in sediments and biota. Nanoparticle infiltration in deeper sediment and soil layers was also limited. We expect that a small fraction of nanoparticles remaining in the water for several weeks can be transported over large distances in rivers. The Ag-NPs accumulated in the top layer of sediment and soil may serve as a source of toxic Ag+ ions or may be remobilized due to changing physico-chemical conditions. Furthermore, the high enrichment of Ag-NPs on algae (up to 250 000-fold) and leaves (up to 11 000-fold) bears risk for organisms feeding on those resources and for the transfer of Ag within the food web.
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| 6. |
- Bundschuh, Mirco
(författare)
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Impact of chemical composition of ecotoxicological test media on the stability and aggregation status of silver nanoparticles
- 2016
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Ingår i: Environmental Science: Nano. - : Royal Society of Chemistry (RSC). - 2051-8153 .- 2051-8161. ; 3, s. 418-433
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Tidskriftsartikel (refereegranskat)abstract
- Understanding of the interplay of generally known colloidal transformations under conditions of test media (TM) used during cultivation of organisms and biological effect (=ecotoxicological) studies is still limited, although this knowledge is required for an adequate interpretation of test outcomes and for a comparison among different studies. In this context, we investigated the aggregation and dissolution dynamics of citrate-stabilized silver nanoparticles (Ag NPs) by varying the composition of three TM (ASTM, SAM-5S, and R2A, used during bioassays with Daphnia magna, Gammarus fossarum, and bacterial biofilms, respectively) in the presence and absence of two types of natural organic matter (NOM), namely, Suwanee River humic acid (SRHA) and seaweed extract (SW). Each original test medium induced reaction-limited aggregation of Ag NPs, and aggregation increased from R2A to SAM-5S and ASTM. In addition to the differences in aggregation dynamics, the concentration and speciation of Ag(I) differed between the three TM, whereby SAM-5S and ASTM are comparable with respect to the nature of the aggregation process but clearly differ from the R2A medium. Furthermore, Cl-, mainly present in SAM-5S, induced NP stabilization. The release of silver ions from Ag NPs was controlled by the presence of NOM and organic constituents of TM and by interactions with Cl- and Br-. The degree of aggregation, formation of interparticle cation-NOM bridges or stabilization was larger for Ca2+ than for Mg2+ due to the stronger ability of Ca2+ to interact with citrate or NOM compared to Mg2+. These observations and the dependence of aggregation rates on the particle concentration renders the interpretation of dose-response relationships challenging, but they may open perspectives for targeted ecotoxicological testing by modifications of TM composition.
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| 7. |
- Cornelis, Geert
(författare)
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Effect of deposition, detachment and aggregation processes on nanoparticle transport in porous media using Monte Carlo simulations
- 2021
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Ingår i: Environmental Science: Nano. - : Royal Society of Chemistry (RSC). - 2051-8153 .- 2051-8161. ; , s. 2223-2234
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Tidskriftsartikel (refereegranskat)abstract
- A novel off-lattice three-dimensional coarse-grained Monte Carlo model is developed to study engineered nanoparticle (ENP) behavior in porous media. Based on individual particle tracking and on the assumption that different physicochemical processes may occur with different probabilities, our model is used to independently evaluate the influence of homoaggregation, attachment and detachment processes on ENP transport and retention inside porous media made of colloidal collectors. The possibility of straining, i.e. trapping of ENPs or aggregates that are too large to pass pore necks, is also included in the model. The overall probability of ENP retention as a function of the above mentioned processes is quantified using functional tests in the form of a alpha(global)(t(ref)) retention parameter. High alpha(global)(t(ref)) values were obtained for moderate probabilities of homoaggregation between ENPs (alpha(ENP-ENP)) and very small probabilities of attachment between ENPs and collectors (alpha(att)), thus indicating the important role of homoaggregation and attachment in ENP retention. Moreover, attaching ENPs and large aggregates was found to cause pore neck enclosure and thus largely contributed to the straining of unbound ENPs. An analysis of depth distribution of retained ENPs revealed that, depending on the dominating conditions, the number of ENPs was decreasing monotonously or exponentially with depth. The introduction of the ENP detachment probability (alpha(det)) from collectors resulted in an increased ENP occurrence at the porous media matrix outlet. It was also found that different sets of alpha(det) and alpha(att) values, reflecting different ENPs and collector physicochemical properties and inter-particle forces, lead to identical alpha(global)(t(ref)) values. This constitutes an important outcome indicating that alpha(global)(t(ref)) values determined from functional tests are not mechanistic but operationally defined parameters and thus cannot be deemed predictive beyond these tests.
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| 8. |
- Cornelis, Geert
(författare)
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Harmonizing across environmental nanomaterial testing media for increased comparability of nanomaterial datasets
- 2020
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Ingår i: Environmental Science: Nano. - : Royal Society of Chemistry (RSC). - 2051-8153 .- 2051-8161. ; 7, s. 13-36
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Tidskriftsartikel (refereegranskat)abstract
- The chemical composition and properties of environmental media determine nanomaterial (NM) transport, fate, biouptake, and organism response. To compare and interpret experimental data, it is essential that sufficient context be provided for describing the physical and chemical characteristics of the setting in which a nanomaterial may be present. While the nanomaterial environmental, health and safety (NanoEHS) field has begun harmonization to allow data comparison and re-use (e.g. using standardized materials, defining a minimum set of required material characterizations), there is limited guidance for standardizing test media. Since most of the NM properties driving environmental behaviour and toxicity are medium-dependent, harmonization of media is critical. A workshop in March 2016 at Duke University identified five categories of test media: aquatic testing media, soil and sediment testing media, biological testing media, engineered systems testing media and product matrix testing media. For each category of test media, a minimum set of medium characteristics to report in all NM tests is recommended. Definitions and detail level of the recommendations for specific standardized media vary across these media categories. This reflects the variation in the maturity of their use as a test medium and associated measurement techniques, variation in utility and relevance of standardizing medium properties, ability to simplify standardizing reporting requirements, and in the availability of established standard reference media. Adoption of these media harmonization recommendations will facilitate the generation of integrated comparable datasets on NM fate and effects. This will in turn allow testing of the predictive utility of functional assay measurements on NMs in relevant media, support investigation of first principles approaches to understand behavioral mechanisms, and support categorization strategies to guide research, commercial development, and policy.
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| 9. |
- Cornelis, G., et al.
(författare)
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Sludge concentration, shear rate and nanoparticle size determine silver nanoparticle removal during wastewater treatment
- 2017
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Ingår i: Environmental Science-Nano. - : Royal Society of Chemistry (RSC). - 2051-8153 .- 2051-8161. ; 4:11, s. 2225-2234
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Tidskriftsartikel (refereegranskat)abstract
- Wastewater treatment (WWT) is generally efficient in removing nanoparticles (NPs) from sewage effluent, but the variety in removal rates has not yet been explained. WWT parameters such as the activated sludge (AS) concentration, shear rate and ionic strength were varied in kinetic batch attachment and sedimentation studies using silver NPs having nominal 20 or 80 nm sizes and citrate or PEG coatings. The fitted attachment and detachment rate constants and the resulting distribution ratios at steady state varied with WWT process parameters, but most notably with the NP size, which was also found to influence the settling rates most. The NP coating molecules had a limited or no effect. A meta-analysis of literature distribution ratios (attached/detached concentration) of NPs composed of Ag and other materials showed the NP (aggregate) size as the only significant parameter. However, while the distribution ratio of silver NPs to AS increased linearly with AS concentration, the final effect of NP effluent concentrations is partly offset by decreased sedimentation rates. The results thus confirm that a WWT process is efficient in removing NPs from wastewater, but relatively small (<20 nm) non-aggregated NPs are somewhat more likely to exit a WWT process via the effluent into aquatic compartments compared to relatively larger NPs, which nearly entirely leave the WWT plants with the AS towards soils, incineration plants or landfills.
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| 10. |
- Cornelis, Geert
(författare)
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Sludge concentration, shear rate and nanoparticle size determine silver nanoparticle removal during wastewater treatment
- 2017
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Ingår i: Environmental Science: Nano. - 2051-8153 .- 2051-8161. ; 4, s. 2225-2234
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Tidskriftsartikel (refereegranskat)abstract
- Wastewater treatment (WWT) is generally efficient in removing nanoparticles (NPs) from sewage effluent, but the variety in removal rates has not yet been explained. WWT parameters such as the activated sludge (AS) concentration, shear rate and ionic strength were varied in kinetic batch attachment and sedimentation studies using silver NPs having nominal 20 or 80 nm sizes and citrate or PEG coatings. The fitted attachment and detachment rate constants and the resulting distribution ratios at steady state varied with WWT process parameters, but most notably with the NP size, which was also found to influence the settling rates most. The NP coating molecules had a limited or no effect. A meta-analysis of literature distribution ratios (attached/detached concentration) of NPs composed of Ag and other materials showed the NP (aggregate) size as the only significant parameter. However, while the distribution ratio of silver NPs to AS increased linearly with AS concentration, the final effect of NP effluent concentrations is partly offset by decreased sedimentation rates. The results thus confirm that a WWT process is efficient in removing NPs from wastewater, but relatively small (<20 nm) non-aggregated NPs are somewhat more likely to exit a WWT process via the effluent into aquatic compartments compared to relatively larger NPs, which nearly entirely leave the WWT plants with the AS towards soils, incineration plants or landfills.
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