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Franz P, Bürkle A, Wick P, Hirsch C. Exploring Flow Cytometry-Based Micronucleus Scoring for Reliable Nanomaterial Genotoxicity Assessment. Chem Res Toxicol 2020; 33:2538-2549. [PMID: 32945164 DOI: 10.1021/acs.chemrestox.0c00071] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The increased use of engineered nanomaterials (ENM) such as SiO2 and TiO2 in industrial products, especially in food, raises concerns with regard to their effect on human health. In particular, ENM-induced genotoxicity is crucial to investigate, since DNA damage can cause induction or promotion of carcinogenesis. However, current in vitro and in vivo nanogenotoxicological data are highly contradictory, which impedes interpretation and extrapolation. Hence, robust, reliable, and ideally scalable in vitro methods for nanogenotoxicity assessment are of great interest. This work aimed at evaluating the suitability of flow cytometry-based micronuclei scoring for reliable nanogenotoxicological assessment in human intestinal cells. Therefore, we have evaluated the genotoxicity of differently sized SiO2 and TiO2 from different sources (food-relevant, commercially available, and laboratory-synthesized) using the well-established alkaline single cell gel electrophoresis (Comet assay) and the micronucleus (MN) assay employing a flow cytometric readout. Our study demonstrates that physiologically relevant doses of several types of SiO2 and TiO2 did not cause genotoxicity, as assessed by the Comet assay, and the MN flow cytometry assay under the particular experimental conditions described. To improve data reliability, we identified ENM-induced interferences with flow cytometric scoring employing a set of interference controls, which is generally applicable for any nanomaterial and any cell line. In conclusion, flow cytometry-based MN scoring appears to be a promising methodology in nanogenotoxicity testing since data acquisition and analysis are significantly faster, highly scalable in terms of throughput, and less operator-dependent compared to the traditional microscopic evaluation. In particular, ENM-induced false-positive or false-negative results, which have not been addressed sufficiently in the literature, can be detected easily, thus enhancing data reliability.
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Affiliation(s)
- Pauline Franz
- Laboratory for Particles-Biology Interactions, Empa - Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Alexander Bürkle
- Chair of Molecular Toxicology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
| | - Peter Wick
- Laboratory for Particles-Biology Interactions, Empa - Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Cordula Hirsch
- Laboratory for Particles-Biology Interactions, Empa - Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
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Hempt C, Kaiser JP, Scholder O, Buerki-Thurnherr T, Hofmann H, Rippl A, Schuster TB, Wick P, Hirsch C. The impact of synthetic amorphous silica (E 551) on differentiated Caco-2 cells, a model for the human intestinal epithelium. Toxicol In Vitro 2020; 67:104903. [PMID: 32473318 DOI: 10.1016/j.tiv.2020.104903] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/07/2020] [Accepted: 05/20/2020] [Indexed: 12/15/2022]
Abstract
For several decades, food-grade synthetic amorphous silica (SAS) have been used as a technological additive to reduce caking of food powders. Human exposure is thus inevitable and safety concerns are taken seriously. The toxicity of silica in general and SAS in particular has been studied extensively. Overall, there is little evidence that food-grade SAS pose any health risks to humans. However, from the available data it was often not clear which type of silica was used. Accordingly, the latest report of the European food safety authority requested additional toxicity data for well-characterised "real food-grade SAS". To close this gap, we screened a panel of ten well-defined, food-grade SAS for potential adverse effects on differentiated Caco-2 cells. Precipitated and fumed SAS with low, intermediate and high specific surface area were included to determine structure-activity relationships. In a physiological dose-range up to 50 μg/ml and 48 h of incubation, none of the materials induced adverse effects on differentiated Caco-2 cells. This held true for endpoints of acute cytotoxicity as well as epithelial specific measures of barrier integrity. These results showed that despite considerable differences in production routes and material characteristics, food-relevant SAS did not elicit acute toxicity responses in intestinal epithelial cells.
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Affiliation(s)
- Claudia Hempt
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland; Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Jean-Pierre Kaiser
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland
| | - Olivier Scholder
- Nanoscale Materials Science Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf, Switzerland
| | - Tina Buerki-Thurnherr
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland
| | - Heinrich Hofmann
- Institute of Materials, Powder Technology Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Alexandra Rippl
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland
| | - Tobias B Schuster
- Evonik Resource Efficiency GmbH, Rodenbacher Chaussee 4, 63457 Hanau-Wolfgang, Germany
| | - Peter Wick
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland
| | - Cordula Hirsch
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland.
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Bohmer N, Rippl A, May S, Walter A, Heo MB, Kwak M, Roesslein M, Song NW, Wick P, Hirsch C. Interference of engineered nanomaterials in flow cytometry: A case study. Colloids Surf B Biointerfaces 2018; 172:635-645. [PMID: 30243217 DOI: 10.1016/j.colsurfb.2018.09.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 08/23/2018] [Accepted: 09/10/2018] [Indexed: 01/28/2023]
Abstract
Nanotechnology is regarded as the enabling technology of the 21st century. However, only a relatively small number of nano-enabled medical and healthcare products finally made their way to the market. There are several reasons why such innovative approaches fail in translation, with one key factor being the uncertainty surrounding their safety assessment. Although well described, interference reactions of engineered nanomaterials (ENM) with classical cytotoxicity assays remain a major source of uncertainty. Flow cytometry is a powerful, widely used, in vitro technique. Its readout is based on the detection of refracted laser light and fluorescence signals. It is therefore susceptible to ENM interference. Here we investigated possible interferences of ENM in the Annexin V/propidium iodide (PI) assay, which quantifies apoptotic and necrotic cell populations by flow cytometry. Two case studies were conducted using either silica or gold nanoparticles differing in size, specific surface area and surface chemistry. Both ENM types were found to cause distinct interference reactions at realistic concentrations. Silica particles induced false-positive signals; however only in the absence of a protein corona and in conjunction with a particular fluorophore combination (FITC/PI). In contrast, gold particles led to complex quenching effects which were only marginally influenced by the presence of proteins and occurred for both fluorophore combinations analyzed. We present a versatile spike-in approach which is applicable to all ENM and cell types. It further allows for the identification of a broad range of different interference phenomena, thereby increasing the reliability and quality of flow cytometry and ENM hazard assessment.
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Affiliation(s)
- Nils Bohmer
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Alexandra Rippl
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Sarah May
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Aurélie Walter
- Institute of Materials, Powder Technology Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Min Beom Heo
- Korea Research Institute of Standards and Science (KRISS), Yuseong-Gu, Daejeon 305-340, Republic of Korea
| | - Minjeong Kwak
- Korea Research Institute of Standards and Science (KRISS), Yuseong-Gu, Daejeon 305-340, Republic of Korea
| | - Matthias Roesslein
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Nam Woong Song
- Korea Research Institute of Standards and Science (KRISS), Yuseong-Gu, Daejeon 305-340, Republic of Korea
| | - Peter Wick
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Cordula Hirsch
- Laboratory for Particles-Biology Interactions, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland.
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Cimbaluk GV, Ramsdorf WA, Perussolo MC, Santos HKF, Da Silva De Assis HC, Schnitzler MC, Schnitzler DC, Carneiro PG, Cestari MM. Evaluation of multiwalled carbon nanotubes toxicity in two fish species. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 150:215-223. [PMID: 29287268 DOI: 10.1016/j.ecoenv.2017.12.034] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 06/07/2023]
Abstract
Carbon Nanotubes are among the most promising materials for the technology industry. Their unique physical and chemical proprieties may reduce the production costs and improve the efficiency of a large range of products. However, the same characteristics that have made nanomaterials interesting for industry may be responsible for inducing toxic effects on the aquatic organisms. Since the carbon nanotubes toxicity is still a controversial issue, we performed tests of acute and subchronic exposure to a commercial sample of multiwalled carbon nanotubes in two fish species, an exotic model (Danio rerio) and a native one (Astyanax altiparanae). Using the alkaline version of the comet assay on erythrocytes and the piscine micronucleous, also performed on erythrocytes, it was verified that the tested carbon nanotubes sample did not generate apparent genotoxicity by means of single/double DNA strand break or clastogenic/aneugenic effects over any of the species, independently of the exposure period. Although, our findings indicate the possibility of the occurrence of CNTs-DNA crosslinks. Apparently, the sample tested induces oxidative stress after subchronic exposure as shown by activity of superoxide dismutase and catalase. The data obtained by the activity levels of acetylcholinesterase suggests acute neurotoxicity in Astyanax altiparanae and subchronic neurotoxicity in Danio rerio.
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Affiliation(s)
- Giovani Valentin Cimbaluk
- Laboratório de citogenética animal e mutagênese ambiental da Universidade Federal do Paraná, Curitiba, PR, Brazil.
| | - Wanessa Algarte Ramsdorf
- Laboratório de ecotoxicologia da Universidade Tecnológica Federal do Paraná, Curitiba, PR, Brazil
| | | | | | | | - Mariane Cristina Schnitzler
- Laboratório de química orgânica e nanoestruturas da Universidade Federal de São João Del Rei, Campus Centro-Oeste, Divinópolis, MG, Brazil
| | - Danielle Caroline Schnitzler
- Laboratório de Estudos em Matrizes Ambientais: Sedimento, Solo e Água Universidade - Tecnológica Federal do Paraná, Curitiba, PR, Brazil
| | - Pedro Gontijo Carneiro
- Laboratório de química orgânica e nanoestruturas da Universidade Federal de São João Del Rei, Campus Centro-Oeste, Divinópolis, MG, Brazil
| | - Marta Margarete Cestari
- Laboratório de citogenética animal e mutagênese ambiental da Universidade Federal do Paraná, Curitiba, PR, Brazil
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Forest V, Figarol A, Boudard D, Cottier M, Grosseau P, Pourchez J. Adsorption of lactate dehydrogenase enzyme on carbon nanotubes: how to get accurate results for the cytotoxicity of these nanomaterials. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3635-3643. [PMID: 25768724 DOI: 10.1021/acs.langmuir.5b00631] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Carbon nanotube (CNT) cytotoxicity is frequently investigated using in vitro classical toxicology assays. However, these cellular tests, usually based on the use of colorimetric or fluorimetric dyes, were designed for chemicals and may not be suitable for nanosized materials. Indeed, because of their unique physicochemical properties CNT can interfere with the assays and bias the results. To get accurate data and draw reliable conclusions, these artifacts should be carefully taken into account. The aim of this study was to evaluate qualitatively and quantitatively the interferences occurring between CNT and the commonly used lactate dehydrogenase (LDH) assay. Experiments under cell-free conditions were performed, and it was clearly demonstrated that artifacts occurred. They were due to the intrinsic absorbance of CNT on one hand and the adsorption of LDH at the CNT surface on the other hand. The adsorption of LDH on CNT was modeled and was found to fit the Langmuir model. The K(ads) and n(eq) constants were defined, allowing the correction of results obtained from cellular experiments to get more accurate data and lead to proper conclusions on the cytotoxicity of CNT.
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Affiliation(s)
- Valérie Forest
- †Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS, Saint-Etienne, France
- ‡LINA, EA4624, Saint-Etienne, France
- §SFR IFRESIS, Saint-Etienne, France
| | - Agathe Figarol
- ‡LINA, EA4624, Saint-Etienne, France
- §SFR IFRESIS, Saint-Etienne, France
- ∥Ecole Nationale Supérieure des Mines de Saint-Etienne, SPIN, CNRS: UMR 5307, LGF, Saint-Etienne, France
| | - Delphine Boudard
- ‡LINA, EA4624, Saint-Etienne, France
- §SFR IFRESIS, Saint-Etienne, France
- ⊥Faculté de Médecine J. Lisfranc, Université Jean Monnet, Saint-Etienne, France
- #PRES Lyon, France
- ∇CHU, Saint-Etienne, France
| | - Michèle Cottier
- ‡LINA, EA4624, Saint-Etienne, France
- §SFR IFRESIS, Saint-Etienne, France
- ⊥Faculté de Médecine J. Lisfranc, Université Jean Monnet, Saint-Etienne, France
- #PRES Lyon, France
- ∇CHU, Saint-Etienne, France
| | - Philippe Grosseau
- ∥Ecole Nationale Supérieure des Mines de Saint-Etienne, SPIN, CNRS: UMR 5307, LGF, Saint-Etienne, France
| | - Jérémie Pourchez
- †Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS, Saint-Etienne, France
- ‡LINA, EA4624, Saint-Etienne, France
- §SFR IFRESIS, Saint-Etienne, France
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Kaiser JP, Diener L, Wick P. Nanoparticles in paints: A new strategy to protect façades and surfaces? ACTA ACUST UNITED AC 2013. [DOI: 10.1088/1742-6596/429/1/012036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Musa M, Ponnuraj KT, Mohamad D, Rahman IA. Genotoxicity evaluation of dental restoration nanocomposite using comet assay and chromosome aberration test. NANOTECHNOLOGY 2013; 24:015105. [PMID: 23221152 DOI: 10.1088/0957-4484/24/1/015105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Nanocomposite is used as a dental filling to restore the affected tooth, especially in dental caries. The dental nanocomposite (KelFil) for tooth restoration used in this study was produced by the School of Dental Sciences, Universiti Sains Malaysia, Malaysia and is incorporated with monodispersed, spherical nanosilica fillers. The aim of the study was to determine the genotoxic effect of KelFil using in vitro genotoxicity tests. The cytotoxicity and genotoxicity of KelFil was evaluated using MTT assay, comet assay and chromosome aberration tests with or without the addition of a metabolic activation system (S9 mix), using the human lung fibroblast cell line (MRC-5). Concurrent negative and positive controls were included. In the comet assay, no comet formation was found in the KelFil groups. There was a significant difference in tail moment between KelFil groups and positive control (p < 0.05). Similarly, no significant aberrations in chromosomes were noticed in KelFil groups. The mitotic indices of treatment groups and negative control were significantly different from positive controls. Hence, it can be concluded that the locally produced dental restoration nanocomposite (KelFil) is non-genotoxic under the present test conditions.
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Affiliation(s)
- Marahaini Musa
- School of Dental Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
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Hirsch C, Roesslein M, Krug HF, Wick P. Nanomaterial cell interactions: are current in vitro tests reliable? Nanomedicine (Lond) 2011; 6:837-47. [PMID: 21793675 DOI: 10.2217/nnm.11.88] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
New properties of engineered nanomaterials raise great expectations for industrial, scientific as well as medical applications. At the same time concerns among consumers regarding the safety aspects of this new technology emerge. Furthermore, among the multitude of published studies, a considerable number do not reveal reliable data. Thus, standardized, validated, reliable, robust, reproducible and intelligent testing strategies are urgently needed that address nanomaterial toxicity. This article discusses the reliability of currently used in vitro toxicity assays. It covers major problems, pitfalls and challenges of assay performance and validation. We recommend a series of different controls to improve the experimental quality and, thus, also the reliability and reproducibility of current in vitro systems. These recommendations consequently applied in the future will increase the safe and sustainable use of nanotechnology.
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Affiliation(s)
- Cordula Hirsch
- Empa, Swiss Federal Laboratories for Materials Research & Testing, Laboratory for Materials-Biology Interactions, Lerchenfeldstrasse 5, St Gallen, Switzerland
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