Special Issue "Toxicity and Ecotoxicity of Nanomaterials"

A special issue of Nanomaterials (ISSN 2079-4991).

Deadline for manuscript submissions: closed (27 August 2019).

Special Issue Editors

Dr. Paride Mantecca
Website
Guest Editor
Research Center POLARIS (Particulate Matter and Health Risk), Department of Earth and Environmental Sciences, University of Milano-Bicocca, Milan, Italy
Interests: cell biology; developmental biology; nanotoxicology; environmental toxicology; microscopy; air pollution; particulate matter; water pollution; pesticides; antimicrobials; sustainable materials; sustainable processes
Dr. Kaja Kasemets

Guest Editor
Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia

Special Issue Information

Dear Colleagues,

In the past few decades, an enormous research effort has been made by the scientific community in the characterization of the toxic effects produced by several nanomaterials (NMs) on human and environmental health. In addition, many of these studies were affected by experimental gaps, resulting in little useful data for risk assessment. Among them, NM concentration ranges well beyond the measured or estimated ones and the poor physico-chemical characterizations of the NMs in the exposure media. On the one hand, toxicity and ecotoxicity studies must be implemented by adopting realistic, fully-characterized, exposure systems and more predictive biological models; on the other hand, rooms are available for new studies on the biological mode of action of the still growing number of newly synthesized NMs. These advanced materials are, in fact, designed to improve their efficacy by fine tuning their physico-chemical structurea, such as the manipulation of crystalline structure, introduction of doping elements and/or modification of surface chemistry. Obviously, such new properties may drastically influence the modalities by which a NM interacts with a biological system, as well as the final toxicity, making the exploration of how rendering it safer possible. Both the human toxicology and environmental toxicology fields can take advantage from as such safety-by-material design experimental approach, since benefits are expected in term of exposure to less-toxic materials. Nevertheless, it may significantly improve the basic knowledge of the biological structures and mechanisms involved in response to nano-structures.

In this Special Issue, studies dedicated at improving the robustness of toxicity data in humans and other living organisms are welcome, paying special attention to those performed under realistic exposure conditions, using highly-predictive biological models and endpoints, and/or shedding light on the relationships between NM structure and biological modes of action.

The ambitious goal is to contribute by generating data useful for NM risk assessment and to invest nanotoxicology with a proactive role in the safe-by-design implementation of nanotechnologies.

Dr. Paride Mantecca
Dr. Kaja Kasemets
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • nanotoxicology
  • safe-by-design
  • human toxicity
  • ecotoxicity
  • nanoparticles
  • biological mode-of-action

Published Papers (10 papers)

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Research

Open AccessArticle
Mixture Effects of Diesel Exhaust and Metal Oxide Nanoparticles in Human Lung A549 Cells
Nanomaterials 2019, 9(9), 1302; https://doi.org/10.3390/nano9091302 - 11 Sep 2019
Abstract
Airborne ultrafine particles (UFP) mainly derive from combustion sources (e.g., diesel exhaust particles—DEP), abrasion sources (non-exhaust particles) or from the unintentional release of engineered nanoparticles (e.g., metal oxide nanoparticles—NPs), determining human exposure to UFP mixtures. The aim of the present study was to [...] Read more.
Airborne ultrafine particles (UFP) mainly derive from combustion sources (e.g., diesel exhaust particles—DEP), abrasion sources (non-exhaust particles) or from the unintentional release of engineered nanoparticles (e.g., metal oxide nanoparticles—NPs), determining human exposure to UFP mixtures. The aim of the present study was to analyse the combined in vitro effects of DEP and metal oxide NPs (ZnO, CuO) on human lung A549 cells. The mixtures and the relative single NPs (DEP, ZnO, CuO) were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and inductively coupled plasma-optic emission spectroscopy (ICP-OES). Cells were exposed for different times (3–72 h) to mixtures of standard DEP at a subcytotoxic concentration and ZnO and CuO at increasing concentrations. At the end of the exposure, the cytotoxicity was assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and clonogenic tests, the pro-inflammatory potential was evaluated by interleukin-8 (IL-8) release and the cell morphology was investigated by fluorescence and transmission electron microscopy. The obtained results suggest that the presence of DEP may introduce new physico-chemical interactions able to increase the cytotoxicity of ZnO and to reduce that of CuO NPs. Full article
(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)
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Open AccessArticle
Zinc Oxide Nanoparticles Induce Autophagy and Apoptosis via Oxidative Injury and Pro-Inflammatory Cytokines in Primary Astrocyte Cultures
Nanomaterials 2019, 9(7), 1043; https://doi.org/10.3390/nano9071043 - 21 Jul 2019
Cited by 5
Abstract
The present study examined the potential toxic concentrations of zinc oxide nanoparticles (ZnO NPs) and associated autophagy and apoptosis-related injuries in primary neocortical astrocyte cultures. Concentrations of ZnO NPs ≥3 μg/mL induced significant toxicity in the astrocytes. At 24 h after exposure to [...] Read more.
The present study examined the potential toxic concentrations of zinc oxide nanoparticles (ZnO NPs) and associated autophagy and apoptosis-related injuries in primary neocortical astrocyte cultures. Concentrations of ZnO NPs ≥3 μg/mL induced significant toxicity in the astrocytes. At 24 h after exposure to the ZnO NPs, transmission electron microscopy revealed swelling of the endoplasmic reticulum (ER) and increased numbers of autophagolysosomes in the cultured astrocytes, and increased levels of LC3 (microtubule-associated protein 1 light chain 3)-mediated autophagy were identified by flow cytometry. Apoptosis induced by ZnO NP exposure was confirmed by the elevation of caspase-3/7 activity and 4′,6′-diamidino-2-phenylindole (DAPI) staining. Significant (p < 0.05) changes in the levels of glutathione peroxidase, superoxide dismutase, tumor necrosis factor (TNF-α), and interleukin-6 were observed by enzyme-linked immunoassay (ELISA) assay following the exposure of astrocyte cultures to ZnO NPs. Phosphatidylinositol 3-kinase (PI3K)/mitogen-activated protein kinase (MAPK) dual activation was induced by ZnO NPs in a dose-dependent manner. Additionally, the Akt (protein kinase B) inhibitor BML257 and the mTOR (mammalian target of rapamycin) inhibitor rapamycin contributed to the survival of astrocytes. Inhibitors of cyclooxygenase-2 and lipoxygenase attenuated ZnO NP-induced toxicity. Calcium-modulating compounds, antioxidants, and zinc/iron chelators also decreased ZnO NP-induced toxicity. Together, these results suggest that ZnO NP-induced autophagy and apoptosis may be associated with oxidative stress and the inflammatory process in primary astrocyte cultures. Full article
(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)
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Open AccessArticle
In Vitro Toxicity of TiO2:SiO2 Nanocomposites with Different Photocatalytic Properties
Nanomaterials 2019, 9(7), 1041; https://doi.org/10.3390/nano9071041 - 21 Jul 2019
Abstract
The enormous technological relevance of titanium dioxide (TiO2) nanoparticles (NPs) and the consequent concerns regarding potentially hazardous effects that exposure during production, use, and disposal can generate, encourage material scientists to develop and validate intrinsically safe design solution (safe-by-design). Under this [...] Read more.
The enormous technological relevance of titanium dioxide (TiO2) nanoparticles (NPs) and the consequent concerns regarding potentially hazardous effects that exposure during production, use, and disposal can generate, encourage material scientists to develop and validate intrinsically safe design solution (safe-by-design). Under this perspective, the encapsulation in a silica dioxide (SiO2) matrix could be an effective strategy to improve TiO2 NPs safety, preserving photocatalytic and antibacterial properties. In this work, A549 cells were used to investigate the toxic effects of silica-encapsulated TiO2 having different ratios of TiO2 and SiO2 (1:1, 1:3, and 3:1). NPs were characterized by electron microscopy and dynamic light scattering, and cell viability, oxidative stress, morphological changes, and cell cycle alteration were evaluated. Resulting data demonstrated that NPs with lower content of SiO2 are able to induce cytotoxic effects, triggered by oxidative stress and resulting in cell necrosis and cell cycle alteration. The physicochemical properties of NPs are responsible for their toxicity. Particles with small size and high stability interact with pulmonary cells more effectively, and the different ratio among silica and titania plays a crucial role in the induced cytotoxicity. These results strengthen the need to take into account a safe(r)-by-design approach in the development of new nanomaterials for research and manufacturing. Full article
(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)
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Open AccessArticle
Dissolved Organic Matter Modulates Algal Oxidative Stress and Membrane System Responses to Binary Mixtures of Nano-Metal-Oxides (nCeO2, nMgO and nFe3O4) and Sulfadiazine
Nanomaterials 2019, 9(5), 712; https://doi.org/10.3390/nano9050712 - 07 May 2019
Cited by 1
Abstract
Joint biomarker responses, oxidative stress and membrane systems, were determined for nano-metal-oxides (nMeO, i.e., nCeO2, nMgO, and nFe3O4) and sulfadiazine (SDZ) exposed at relevant low concentrations to two freshwater microalgae Scenedesmus obliquus and Chlorella pyrenoidosa. The [...] Read more.
Joint biomarker responses, oxidative stress and membrane systems, were determined for nano-metal-oxides (nMeO, i.e., nCeO2, nMgO, and nFe3O4) and sulfadiazine (SDZ) exposed at relevant low concentrations to two freshwater microalgae Scenedesmus obliquus and Chlorella pyrenoidosa. The impacts of dissolved organic matter (DOM) on the joint biomarker responses were also investigated. Results indicated that the presence of SDZ significantly decreased the level of intercellular reactive oxygen species (ROS) in the algal cells exposed to each nMeO. Reduction of cell membrane permeability (CMP) and mitochondrial membrane potential (MMP) in the algal cells was observed when the algae were exposed to the mixture of SDZ and the nMeO. The degree of reduction of the ROS level, CMP, and MMP significantly went down with the addition of DOM to a certain extent. Changes in cellular oxidative stress and membrane function depended on the types of both nMeO and algal species. This contribution provides an insight into the hazard assessment of a mixture consisting of emerging contaminants and DOM, as they can coexist in the aquatic environment. Full article
(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)
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Open AccessArticle
The Investigation into the Toxic Potential of Iron Oxide Nanoparticles Utilizing Rat Pheochromocytoma and Human Neural Stem Cells
Nanomaterials 2019, 9(3), 453; https://doi.org/10.3390/nano9030453 - 18 Mar 2019
Cited by 1
Abstract
Magnetic iron oxide (Magnetite, Fe3O4) nanoparticles are widely utilized in magnetic resonance imaging (MRI) and drug delivery applications due to their superparamagnetism. Surface coatings are often employed to change the properties of the magnetite nanoparticles or to modulate their [...] Read more.
Magnetic iron oxide (Magnetite, Fe3O4) nanoparticles are widely utilized in magnetic resonance imaging (MRI) and drug delivery applications due to their superparamagnetism. Surface coatings are often employed to change the properties of the magnetite nanoparticles or to modulate their biological responses. In this study, magnetite nanoparticles were fabricated through hydrothermal synthesis. Hydrophobicity is often increased by surface modification with oleic acid. In this study, however, hydrophobicity was introduced through surface modification with n-octyltriethoxysilane. Both the uncoated (hydrophilic) and coated (hydrophobic) individual nanoparticle sizes measured below 20 nm in diameter, a size range in which magnetite nanoparticles exhibit superparamagnetism. Both types of nanoparticles formed aggregates which were characterized by SEM, TEM, and dynamic light scattering (DLS). The coating process significantly increased both individual particle diameter and aggregate sizes. We tested the neurotoxicity of newly synthesized nanoparticles with two mammalian cell lines, PC12 (rat pheochromocytoma) and ReNcell VM (human neural stem cells). Significant differences were observed in cytotoxicity profiles, which suggests that the cell type (rodent versus human) or the presence of serum matters for nanoparticle toxicology studies. Differences in nanoparticle associations/uptake between the two cell types were observed with Prussian Blue staining. Finally, safe concentrations which did not significantly affect neuronal differentiation profiles were identified for further development of the nanoparticles. Full article
(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)
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Open AccessArticle
Pesticide Encapsulation at the Nanoscale Drives Changes to the Hydrophobic Partitioning and Toxicity of an Active Ingredient
Nanomaterials 2019, 9(1), 81; https://doi.org/10.3390/nano9010081 - 09 Jan 2019
Cited by 6
Abstract
Given the costs associated with designing novel active ingredients, new formulations focus on the use of other ingredients to modify existing formulations. Nanosized encapsulated pesticides offer a variety of enhanced features including controlled release and improved efficacy. Despite the presence of nanosized capsules [...] Read more.
Given the costs associated with designing novel active ingredients, new formulations focus on the use of other ingredients to modify existing formulations. Nanosized encapsulated pesticides offer a variety of enhanced features including controlled release and improved efficacy. Despite the presence of nanosized capsules in current-use pesticide formulations, the analytical and toxicological implications of encapsulation are uncertain. To explore this issue quantitatively, we fractionated the capsules of a commercially available encapsulated insecticide formulation (γ-cyhalothrin active ingredient) into two size ranges: a large fraction (LF), with an average hydrodynamic diameter (HDD) of 758 nm, and a small fraction (SF), with an average HDD of 449 nm. We developed a novel extraction method demonstrating a time-dependent inhibition of γ-cyhalothrin from capsules for up to 48 h. An acute immobilization test with a freshwater macroinvertebrate (Ceriodaphnia dubia) revealed that the SF was significantly more toxic than both the LF and the free γ-cyhalothrin treatment (EC50 = 0.18 µg/L, 0.57 µg/L, and 0.65 µg/L, respectively). These findings highlight that encapsulation of γ-cyhalothrin mitigates hydrophobic partitioning in a time-dependent manner and influences toxicity in a size-dependent manner. Recognizing the analytical and toxicological nuances of various nanosized capsules can contribute to innovation in pesticide formulations and may lead to more comprehensive pesticide regulation. Full article
(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)
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Open AccessFeature PaperArticle
Combined Effects of Test Media and Dietary Algae on the Toxicity of CuO and ZnO Nanoparticles to Freshwater Microcrustaceans Daphnia magna and Heterocypris incongruens: Food for Thought
Nanomaterials 2019, 9(1), 23; https://doi.org/10.3390/nano9010023 - 25 Dec 2018
Cited by 4
Abstract
The chemical composition of the test medium as well as the presence of algae (microcrustaceans’ food) affects the bioavailability and thus the toxicity of metal nanoparticles (NP) to freshwater microcrustaceans. This study evaluated the effect of the addition of algae (Rapidocelis subcapitata [...] Read more.
The chemical composition of the test medium as well as the presence of algae (microcrustaceans’ food) affects the bioavailability and thus the toxicity of metal nanoparticles (NP) to freshwater microcrustaceans. This study evaluated the effect of the addition of algae (Rapidocelis subcapitata at 7.5 × 106 cells/mL) on the toxicity of CuO (primary size 22–25 nm) and ZnO NP (10–15 nm) to planktic Daphnia magna and benthic Heterocypris incongruens in artificial (mineral) and natural freshwater (lake water). The toxicity of ionic controls, CuSO4 and ZnSO4, was evaluated in parallel. When algae were added and the toxicity was tested in mineral medium, 48 h EC50 of CuO and ZnO NP to D. magna was ~2 mg metal/L and 6-day LC50 of H. incongruens was 1.1 mg metal/L for CuO and 0.36 mg metal/L for ZnO. The addition of algae to D. magna test medium mitigated the toxicity of CuO and ZnO NP 4–11-fold when the test was conducted in natural water but not in the artificial freshwater. The addition of algae mitigated the toxicity of CuSO4 (but not ZnSO4) to D. magna at least 3-fold, whatever the test medium. In the 6-day H. incongruens tests (all exposures included algae), only up to 2-fold differences in metal NP and salt toxicity between mineral and natural test media were observed. To add environmental relevance to NP hazard assessment for the freshwater ecosystem, toxicity tests could be conducted in natural water and organisms could be fed during the exposure. Full article
(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)
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Open AccessArticle
Cytotoxic, Genotoxic, and Polymorphism Effects on Vanilla planifolia Jacks ex Andrews after Long-Term Exposure to Argovit® Silver Nanoparticles
Nanomaterials 2018, 8(10), 754; https://doi.org/10.3390/nano8100754 - 25 Sep 2018
Cited by 6
Abstract
Worldwide demands of Vanilla planifolia lead to finding new options to produce large-scale and contaminant-free crops. Particularly, the Mexican Government has classified Vanilla planifolia at risk and it subject to protection programs since wild species are in danger of extinction and no more [...] Read more.
Worldwide demands of Vanilla planifolia lead to finding new options to produce large-scale and contaminant-free crops. Particularly, the Mexican Government has classified Vanilla planifolia at risk and it subject to protection programs since wild species are in danger of extinction and no more than 30 clones have been found. Nanotechnology could help to solve both demands and genetic variability, but toxicological concerns must be solved. In this work, we present the first study of the cytotoxic and genotoxic effects promoted by AgNPs in Vanilla planifolia plantlets after a very long exposure time of six weeks. Our results show that Vanilla planifolia plantlets growth with doses of 25 and 50 mg/L is favored with a small decrease in the mitotic index. A dose-dependency in the frequency of cells with chromosomal aberrations and micronuclei was found. However, genotoxic effects could be considered as minimum due to with the highest concentration employed (200 mg/L), the total percentage of chromatic aberrations is lower than 5% with only three micronuclei in 3000 cells, despite the long-time exposure to AgNP. Therefore, 25 and 50 mg/L (1.5 and 3 mg/L of metallic silver) were identified as safe concentrations for Vanilla planifolia growth on in vitro conditions. Exposure of plantlets to AgNPs increase the polymorphism registered by inter-simple sequence repeat method (ISSR), which could be useful to promote the genetic variability of this species. Full article
(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)
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Open AccessArticle
Deep Airway Inflammation and Respiratory Disorders in Nanocomposite Workers
Nanomaterials 2018, 8(9), 731; https://doi.org/10.3390/nano8090731 - 16 Sep 2018
Cited by 5
Abstract
Thousands of researchers and workers worldwide are employed in nanocomposites manufacturing, yet little is known about their respiratory health. Aerosol exposures were characterized using real time and integrated instruments. Aerosol mass concentration ranged from 0.120 mg/m3 to 1.840 mg/m3 during nanocomposite [...] Read more.
Thousands of researchers and workers worldwide are employed in nanocomposites manufacturing, yet little is known about their respiratory health. Aerosol exposures were characterized using real time and integrated instruments. Aerosol mass concentration ranged from 0.120 mg/m3 to 1.840 mg/m3 during nanocomposite machining processes; median particle number concentration ranged from 4.8 × 104 to 5.4 × 105 particles/cm3. The proportion of nanoparticles varied by process from 40 to 95%. Twenty employees, working in nanocomposite materials research were examined pre-shift and post-shift using spirometry and fractional exhaled nitric oxide (FeNO) in parallel with 21 controls. Pro-inflammatory leukotrienes (LT) type B4, C4, D4, and E4; tumor necrosis factor (TNF); interleukins; and anti-inflammatory lipoxins (LXA4 and LXB4) were analyzed in their exhaled breath condensate (EBC). Chronic bronchitis was present in 20% of researchers, but not in controls. A significant decrease in forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) was found in researchers post-shift (p ˂ 0.05). Post-shift EBC samples were higher for TNF (p ˂ 0.001), LTB4 (p ˂ 0.001), and LTE4 (p ˂ 0.01) compared with controls. Nanocomposites production was associated with LTB4 (p ˂ 0.001), LTE4 (p ˂ 0.05), and TNF (p ˂ 0.001), in addition to pre-shift LTD4 and LXB4 (both p ˂ 0.05). Spirometry documented minor, but significant, post-shift lung impairment. TNF and LTB4 were the most robust markers of biological effects. Proper ventilation and respiratory protection are required during nanocomposites processing. Full article
(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)
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Open AccessArticle
Markers of Oxidative Stress in the Exhaled Breath Condensate of Workers Handling Nanocomposites
Nanomaterials 2018, 8(8), 611; https://doi.org/10.3390/nano8080611 - 10 Aug 2018
Cited by 7
Abstract
Researchers in nanocomposite processing may inhale a variety of chemical agents, including nanoparticles. This study investigated airway oxidative stress status in the exhaled breath condensate (EBC). Nineteen employees (42.4 ± 11.4 y/o), working in nanocomposites research for 18.0 ± 10.3 years were examined [...] Read more.
Researchers in nanocomposite processing may inhale a variety of chemical agents, including nanoparticles. This study investigated airway oxidative stress status in the exhaled breath condensate (EBC). Nineteen employees (42.4 ± 11.4 y/o), working in nanocomposites research for 18.0 ± 10.3 years were examined pre-shift and post-shift on a random workday, together with nineteen controls (45.5 ± 11.7 y/o). Panels of oxidative stress biomarkers derived from lipids, nucleic acids, and proteins were analyzed in the EBC. Aerosol exposures were monitored during three major nanoparticle generation operations: smelting and welding (workshop 1) and nanocomposite machining (workshop 2) using a suite of real-time and integrated instruments. Mass concentrations during these operations were 0.120, 1.840, and 0.804 mg/m3, respectively. Median particle number concentrations were 4.8 × 104, 1.3 × 105, and 5.4 × 105 particles/cm3, respectively. Nanoparticles accounted for 95, 40, and 61%, respectively, with prevailing Fe and Mn. All markers of nucleic acid and protein oxidation, malondialdehyde, and aldehydes C6–C13 were elevated, already in the pre-shift samples relative to controls in both workshops. Significant post-shift elevations were documented in lipid oxidation markers. Significant associations were found between working in nanocomposite synthesis and EBC biomarkers. More research is needed to understand the contribution of nanoparticles from nanocomposite processing in inducing oxidative stress, relative to other co-exposures generated during welding, smelting, and secondary oxidation processes, in these workshops. Full article
(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)
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