1
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Pingrey B, Ede JD, Sayes CM, Shatkin JA, Stark N, Hsieh YL. Aqueous exfoliation and dispersion of monolayer and bilayer graphene from graphite using sulfated cellulose nanofibrils. RSC Adv 2024; 14:9860-9868. [PMID: 38528919 PMCID: PMC10962021 DOI: 10.1039/d4ra00424h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 03/14/2024] [Indexed: 03/27/2024] Open
Abstract
Amphiphilic sulfated cellulose nanofibrils were synthesized with yields in excess of 99% by sulfation of dissolving pulp cellulose using chlorosulfonic acid in anhydrous N,N-dimethyl formamide followed by high-speed blending. The sulfation level was stoichiometrically tunable to between 1.48 and 2.23 mmol g-1. The optimized SCNF demonstrated the ability to act as an effective dispersant for graphene produced via exfoliation in aqueous media, allowing for the production of aqueous stabilized graphene with 3.9 ± 0.3 wt% graphite to graphene conversion and suspended solids comprised of 19.5 ± 1.5 wt% graphene. Graphene exfoliated with SCNF was observed to consist exclusively of mono- and bilayers, with 42% of sheets being monolayer. Furthermore, it was demonstrated that SCNF defibrillation and graphene exfoliation could be combined into a single one-pot process.
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Affiliation(s)
- Benjamin Pingrey
- Biological and Agricultural Engineering, Chemical Engineering, University of California at Davis Davis CA 95616-8722 USA +1 530 752 0843
| | - James D Ede
- Vireo Advisors, LLC PO Box 51368 Boston MA 02130 USA
| | | | | | - Nicole Stark
- USDA Forest Service, Forest Products Laboratory Madison WI 53726-2398 USA
| | - You-Lo Hsieh
- Biological and Agricultural Engineering, Chemical Engineering, University of California at Davis Davis CA 95616-8722 USA +1 530 752 0843
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2
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Guo M, Ede JD, Sayes CM, Shatkin JA, Stark N, Hsieh YL. Regioselectively Carboxylated Cellulose Nanofibril Models from Dissolving Pulp: C6 via TEMPO Oxidation and C2,C3 via Periodate-Chlorite Oxidation. Nanomaterials (Basel) 2024; 14:479. [PMID: 38470807 DOI: 10.3390/nano14050479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 02/29/2024] [Accepted: 03/05/2024] [Indexed: 03/14/2024]
Abstract
Regioselective C6 and C2,C3 carboxylated cellulose nanofibrils (CNFs) have been robustly generated from dissolving pulp, a readily available source of unmodified cellulose, via stoichiometrically optimized 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO)-mediated and sequential sodium periodate-sodium chlorite (PC) oxidation coupled with high-speed blending. Both regioselectively optimized carboxylated CNF series possess the widest ranges of comparable charges (0.72-1.48 mmol/g for T-CNFs vs. 0.72-1.10 mmol/g for PC-CNFs), but similar ranges of thickness (1.3-2.4 nm for T-CNF, 1.8-2.7 nm PC-CNF), widths (4.6-6.6 nm T-CNF, 5.5-5.9 nm PC-CNF), and lengths (254-481 nm T-CNF, 247-442 nm PC-CNF). TEMPO-mediated oxidation is milder and one-pot, thus more time and process efficient, whereas the sequential periodate-chlorite oxidation produces C2,C3 dialdehyde intermediates that are amenable to further chemical functionalization or post-reactions. These two well-characterized regioselectively carboxylated CNF series represent coherent cellulose nanomaterial models from a single woody source and have served as references for their safety study toward the development of a safer-by-design substance evaluation tool.
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Affiliation(s)
- Mengzhe Guo
- Chemical Engineering, University of California at Davis, Davis, CA 95616, USA
| | - James D Ede
- Vireo Advisors, LLC, P.O. Box 51368, Boston, MA 02130, USA
| | | | | | - Nicole Stark
- USDA Forest Service, Forest Products Laboratory, Madison, WI 53726, USA
| | - You-Lo Hsieh
- Biological and Agricultural Engineering, Chemical Engineering, University of California at Davis, Davis, CA 95616, USA
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3
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Ede JD, Diges AS, Zhang Y, Shatkin JA. Life-cycle risk assessment of graphene-enabled textiles in fire protection gear. NanoImpact 2024; 33:100488. [PMID: 37940075 DOI: 10.1016/j.impact.2023.100488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 10/06/2023] [Accepted: 11/03/2023] [Indexed: 11/10/2023]
Abstract
A nanomaterial life-cycle risk assessment (Nano LCRA) of a graphene-enabled textile used in the construction of heat and fire-resistant personal protective equipment (PPE) was conducted to develop, analyze, and prioritize potential occupational, health and environmental risks. The analysis identifies potential receptors and exposure pathways at each product life-cycle stage and makes a qualitative evaluation of the potential significance of each scenario. A literature review, quality evaluation, and database were developed as part of the LCRA to identify potential hazards associated with graphene-based materials (GBMs) throughout the product life-cycle. Generally, risks identified from graphene-enabled textiles were low. Of the developed exposure scenarios, occupational inhalation exposures during raw material and product manufacturing ranked highest. The analysis identifies the key potential human and environmental hazards and exposures of the products across the product life-cycle of graphene enabled textiles. Priority research gaps to reduce uncertainty include evaluating long-term, low dose graphene exposures typical of the workplace, as well as the potential release and hazard characterization of graphene-acrylic nanocomposites.
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Affiliation(s)
| | | | - Yueyang Zhang
- Vireo Advisors LLC, Boston, MA 02205, USA; University of Alberta, Edmonton, Alberta, Canada
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Ong KJ, Tejeda-Saldana Y, Duffy B, Holmes D, Kukk K, Shatkin JA. Cultured Meat Safety Research Priorities: Regulatory and Governmental Perspectives. Foods 2023; 12:2645. [PMID: 37509737 PMCID: PMC10379195 DOI: 10.3390/foods12142645] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/23/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023] Open
Abstract
As with every new technology, safety demonstration is a critical component of bringing products to market and gaining public acceptance for cultured meat and seafood. This manuscript develops research priorities from the findings of a series of interviews and workshops with governmental scientists and regulators from food safety agencies in fifteen jurisdictions globally. The interviews and workshops aimed to identify the key safety questions and priority areas of research. Participants raised questions about which aspects of cultured meat and seafood production are novel, and the implications of the paucity of public information on the topic. Novel parameters and targets may require the development of new analytical methods or adaptation and validation of existing ones, including for a diversity of product types and processes. Participants emphasized that data sharing of these efforts would be valuable, similar to those already developed and used in the food and pharmaceutical fields. Contributions to such databases from the private and public sectors would speed general understanding as well as efforts to make evaluations more efficient. In turn, these resources, combined with transparent risk assessment, will be critical elements of building consumer trust in cultured meat and seafood products.
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Affiliation(s)
| | | | | | - Dwayne Holmes
- Stichting New Harvest Netherlands, 1052 Amsterdam, The Netherlands
| | - Kora Kukk
- Vireo Advisors, LLC, Boston, MA 02130, USA
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Ong KJ, Johnston J, Datar I, Sewalt V, Holmes D, Shatkin JA. Food safety considerations and research priorities for the cultured meat and seafood industry. Compr Rev Food Sci Food Saf 2021; 20:5421-5448. [PMID: 34633147 DOI: 10.1111/1541-4337.12853] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 08/31/2021] [Accepted: 09/04/2021] [Indexed: 12/14/2022]
Abstract
Cell-cultured meat and seafood offer a sustainable opportunity to meet the world's increasing demand for protein in a climate-changed world. A responsible, data-driven approach to assess and demonstrate safety of cell-cultured meat and seafood can support consumer acceptance and help fully realize the potential of these products. As an initial step toward a thorough demonstration of safety, this review identifies hazards that could be introduced during manufacturing, evaluates applicability of existing safety assessment approaches, and highlights research priorities that could support safe commercialization. Input was gathered from members of the cultured meat and seafood industry, researchers, regulators, and food safety experts. A series of workshops were held with 87 industry representatives and researchers to create a modular manufacturing process diagram, which served as a framework to identify potential chemical and biological hazards along the steps of the manufacturing process that could affect the safety of a final food product. Interviews and feedback on draft documents validated the process diagram and supported hazard identification and evaluation of applicable safety methods. Most hazards are not expected to be novel; therefore, safety assessment methods from a range of fields, such as conventional and novel foods, foods produced from biotechnology, pharmaceuticals, and so forth, are likely to be applicable. However, additional assessment of novel inputs or products with significant differences from existing foods may be necessary. Further research on the safety of the inputs and associated residues, potential for contamination, and development of standardized safety assessment approaches (particularly animal-free methods) is recommended.
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Affiliation(s)
| | | | - Isha Datar
- New Harvest Inc., Cambridge, Massachusetts, USA
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Patel I, Woodcock J, Beams R, Stranick SJ, Nieuwendaal R, Gilman JW, Mulenos MR, Sayes CM, Salari M, DeLoid G, Demokritou P, Harper B, Harper S, Ong KJ, Shatkin JA, Fox DM. Fluorescently Labeled Cellulose Nanofibers for Environmental Health and Safety Studies. Nanomaterials (Basel) 2021; 11:1015. [PMID: 33921179 PMCID: PMC8071547 DOI: 10.3390/nano11041015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 12/12/2022]
Abstract
An optimal methodology for locating and tracking cellulose nanofibers (CNFs) in vitro and in vivo is crucial to evaluate the environmental health and safety properties of these nanomaterials. Here, we report the use of a new boron-dipyrromethene (BODIPY) reactive fluorescent probe, meso-DichlorotriazineEthyl BODIPY (mDTEB), tailor-made for labeling CNFs used in simulated or in vivo ingestion exposure studies. Time-correlated single photon counting (TCSPC) fluorescence lifetime imaging microscopy (FLIM) was used to confirm covalent attachment and purity of mDTEB-labeled CNFs. The photoluminescence properties of mDTEB-labeled CNFs, characterized using fluorescence spectroscopy, include excellent stability over a wide pH range (pH2 to pH10) and high quantum yield, which provides detection at low (μM) concentrations. FLIM analysis also showed that lignin-like impurities present on the CNF reduce the fluorescence of the mDTEB-labeled CNF, via quenching. Therefore, the chemical composition and the methods of CNF production affect subsequent studies. An in vitro triculture, small intestinal, epithelial model was used to assess the toxicity of ingested mDTEB-labeled CNFs. Zebrafish (Danio rerio) were used to assess in vivo environmental toxicity studies. No cytotoxicity was observed for CNFs, or mDTEB-labeled CNFs, either in the triculture cells or in the zebrafish embryos.
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Affiliation(s)
- Ilabahen Patel
- Department of Chemistry, American University, Washington, DC 20016, USA;
| | - Jeremiah Woodcock
- Materials Science and Engineering Division, Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA; (J.W.); (R.B.); (S.J.S.); (R.N.); (J.W.G.)
| | - Ryan Beams
- Materials Science and Engineering Division, Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA; (J.W.); (R.B.); (S.J.S.); (R.N.); (J.W.G.)
| | - Stephan J. Stranick
- Materials Science and Engineering Division, Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA; (J.W.); (R.B.); (S.J.S.); (R.N.); (J.W.G.)
| | - Ryan Nieuwendaal
- Materials Science and Engineering Division, Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA; (J.W.); (R.B.); (S.J.S.); (R.N.); (J.W.G.)
| | - Jeffrey W. Gilman
- Materials Science and Engineering Division, Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA; (J.W.); (R.B.); (S.J.S.); (R.N.); (J.W.G.)
| | - Marina R. Mulenos
- Department of Environmental Science, Baylor University, Waco, TX 76798, USA; (M.R.M.); (C.M.S.)
| | - Christie M. Sayes
- Department of Environmental Science, Baylor University, Waco, TX 76798, USA; (M.R.M.); (C.M.S.)
| | - Maryam Salari
- Department of Environmental Health, Center for Nanotechnology and Nanotoxicology, T.H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA; (M.S.); (G.D.); (P.D.)
| | - Glen DeLoid
- Department of Environmental Health, Center for Nanotechnology and Nanotoxicology, T.H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA; (M.S.); (G.D.); (P.D.)
| | - Philip Demokritou
- Department of Environmental Health, Center for Nanotechnology and Nanotoxicology, T.H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA; (M.S.); (G.D.); (P.D.)
| | - Bryan Harper
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA; (B.H.); (S.H.)
| | - Stacey Harper
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA; (B.H.); (S.H.)
| | - Kimberly J. Ong
- Vireo Advisors, LLC, Boston, MA 02130, USA; (K.J.O.); (J.A.S.)
| | - Jo Anne Shatkin
- Vireo Advisors, LLC, Boston, MA 02130, USA; (K.J.O.); (J.A.S.)
| | - Douglas M. Fox
- Department of Chemistry, American University, Washington, DC 20016, USA;
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7
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Ede JD, Ong KJ, Mulenos MR, Pradhan S, Gibb M, Sayes CM, Shatkin JA. Physical, chemical, and toxicological characterization of sulfated cellulose nanocrystals for food-related applications using in vivo and in vitro strategies. Toxicol Res (Camb) 2021; 9:808-822. [PMID: 33447365 DOI: 10.1093/toxres/tfaa082] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 09/10/2020] [Accepted: 10/09/2020] [Indexed: 11/14/2022] Open
Abstract
Cellulose nanocrystals (CNCs) are a next-generation cellulose product with many unique properties including applications in the food industry as a food additive, food coating, and in food-contact packaging material. While CNC is anticipated to be safe due to its similarity to the many forms of cellulose currently used as food additives, special consideration is given to it as it is the first manufactured form of cellulose that is nanoscale in both length and width. A proactive approach to safety has been adopted by manufacturers to demonstrate CNC safety toward responsible commercialization. As part of the safety demonstration, in vivo and in vitro testing strategies were commissioned side-by-side with conventional cellulose, which has been safely used in food for decades. Testing included a 90-day rodent feeding study as well as additional physical, chemical, and biological studies in vitro that follow European Food Safety Authority (EFSA) guidance to demonstrate the safe use of novel food ingredients. The strategy includes assessment of neat materials side-by-side with simulated digestion, mimicking conditions that occur along the gastrointestinal tract as well as intracellularly. An intestinal co-culture model examined any potential toxicological effects from exposure to either pristine or digested forms of CNC including cytotoxicity, metabolic activity, membrane permeability, oxidative stress, and proinflammatory responses. None of the studies demonstrated any toxicity via oral or simulated oral exposure. These studies demonstrate that CNC produced by InnoTech Alberta is similarly safe by ingestion as conventional cellulose with a no-observed-adverse-effect level of 2085.3 (males) and 2682.8 (females) mg/kg/day.
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Affiliation(s)
- James D Ede
- Vireo Advisors LLC, Boston, MA 02130-4323, USA
| | | | - Marina R Mulenos
- Institute of Biomedical Studies, Baylor University, One Bear Place #97266, Waco, TX 76798-7266, USA
| | - Sahar Pradhan
- Institute of Biomedical Studies, Baylor University, One Bear Place #97266, Waco, TX 76798-7266, USA
| | - Matthew Gibb
- Department of Environmental Science, Baylor University, One Bear Place #97266, Waco, TX 76798-7266, USA
| | - Christie M Sayes
- Institute of Biomedical Studies, Baylor University, One Bear Place #97266, Waco, TX 76798-7266, USA
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Halappanavar S, Ede JD, Mahapatra I, Krug HF, Kuempel ED, Lynch I, Vandebriel RJ, Shatkin JA. A methodology for developing key events to advance nanomaterial-relevant adverse outcome pathways to inform risk assessment. Nanotoxicology 2020; 15:289-310. [PMID: 33317378 DOI: 10.1080/17435390.2020.1851419] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Significant advances have been made in the development of Adverse Outcome Pathways (AOPs) over the last decade, mainly focused on the toxicity mechanisms of chemicals. These AOPs, although relevant to manufactured nanomaterials (MNs), do not currently capture the reported roles of size-associated properties of MNs on toxicity. Moreover, some AOs of relevance to airborne exposures to MNs such as lung inflammation and fibrosis shown in animal studies may not be targeted in routine regulatory decision making. The primary objective of the present study was to establish an approach to advance the development of AOPs of relevance to MNs using existing, publicly available, nanotoxicology literature. A systematic methodology was created for curating, organizing and applying the available literature for identifying key events (KEs). Using a case study approach, the study applied the available literature to build the biological plausibility for 'tissue injury', a KE of regulatory relevance to MNs. The results of the analysis reveal the various endpoints, assays and specific biological markers used for assessing and reporting tissue injury. The study elaborates on the limitations and opportunities of the current nanotoxicology literature and provides recommendations for the future reporting of nanotoxicology results that will expedite not only the development of AOPs for MNs but also aid in application of existing data for decision making.
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Affiliation(s)
- Sabina Halappanavar
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Canada
| | | | - Indrani Mahapatra
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Harald F Krug
- Retired International Research Cooperation Manager, Empa - Swiss Federal Laboratories for Science and Materials Technology, St. Gallen, Switzerland.,NanoCASE GmbH, Engelburg, Switzerland
| | - Eileen D Kuempel
- National Institute for Occupational Safety and Health, Nanotechnology Research Center, Cincinnati, OH, USA
| | - Iseult Lynch
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Rob J Vandebriel
- National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
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Ede JD, Lobaskin V, Vogel U, Lynch I, Halappanavar S, Doak SH, Roberts MG, Shatkin JA. Translating Scientific Advances in the AOP Framework to Decision Making for Nanomaterials. Nanomaterials (Basel) 2020; 10:E1229. [PMID: 32599945 PMCID: PMC7353114 DOI: 10.3390/nano10061229] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 02/07/2023]
Abstract
Much of the current innovation in advanced materials is occurring at the nanoscale, specifically in manufactured nanomaterials (MNs). MNs display unique attributes and behaviors, and may be biologically and physically unique, making them valuable across a wide range of applications. However, as the number, diversity and complexity of MNs coming to market continue to grow, assessing their health and environmental risks with traditional animal testing approaches is too time- and cost-intensive to be practical, and is undesirable for ethical reasons. New approaches are needed that meet current requirements for regulatory risk assessment while reducing reliance on animal testing and enabling safer-by-design product development strategies to be implemented. The adverse outcome pathway (AOP) framework presents a sound model for the advancement of MN decision making. Yet, there are currently gaps in technical and policy aspects of AOPs that hinder the adoption and use for MN risk assessment and regulatory decision making. This review outlines the current status and next steps for the development and use of the AOP framework in decision making regarding the safety of MNs. Opportunities and challenges are identified concerning the advancement and adoption of AOPs as part of an integrated approach to testing and assessing (IATA) MNs, as are specific actions proposed to advance the development, use and acceptance of the AOP framework and associated testing strategies for MN risk assessment and decision making. The intention of this review is to reflect the views of a diversity of stakeholders including experts, researchers, policymakers, regulators, risk assessors and industry representatives on the current status, needs and requirements to facilitate the future use of AOPs in MN risk assessment. It incorporates the views and feedback of experts that participated in two workshops hosted as part of an Organization for Economic Cooperation and Development (OECD) Working Party on Manufactured Nanomaterials (WPMN) project titled, "Advancing AOP Development for Nanomaterial Risk Assessment and Categorization", as well as input from several EU-funded nanosafety research consortia.
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Affiliation(s)
| | - Vladimir Lobaskin
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland;
| | - Ulla Vogel
- National Research Centre for the Working Environment, DK-2100 Copenhagen, Denmark;
| | - Iseult Lynch
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK;
| | - Sabina Halappanavar
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON K1A 0K9, Canada;
| | - Shareen H. Doak
- Institute of Life Sciences, Swansea University Medical School, Singleton Park, Swansea SA2 8PP, UK;
| | - Megan G. Roberts
- Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada;
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10
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Pradhan SH, Mulenos MR, Steele LR, Gibb M, Ede JD, Ong KJ, Shatkin JA, Sayes CM. Physical, chemical, and toxicological characterization of fibrillated forms of cellulose using an in vitro gastrointestinal digestion and co-culture model. Toxicol Res (Camb) 2020; 9:290-301. [PMID: 32670560 PMCID: PMC7329166 DOI: 10.1093/toxres/tfaa026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 01/18/2023] Open
Abstract
Fibrillated cellulose is a next-generation material in development for a variety of applications, including use in food and food-contact materials. An alternative testing strategy including simulated digestion was developed to compare the physical, chemical, and biological characteristics of seven different types of fibrillated cellulose, following European Food Safety Authority guidance. Fibrillated forms were compared to a conventional form of cellulose which has been used in food for over 85 years and has Generally Recognized as safe regulatory status in the USA. The physical and chemical characterization of fibrillated celluloses demonstrate that these materials are similar physically and chemically, which composed of the same fundamental molecular structure and exhibit similar morphology, size, size distribution, surface charge, and low levels of impurities. Simulated gastrointestinal and lysosomal digestions demonstrate that these physical and chemical similarities remain following exposure to conditions that mimic the gastrointestinal tract or intracellular lysosomes. A toxicological investigation with an advanced intestinal co-culture model found that exposure to each of the fibrillated and conventional forms of cellulose, in either the pristine or digested form at 0.4% by weight, showed no adverse toxicological effects including cytotoxicity, barrier integrity, oxidative stress, or inflammation. The results demonstrate the physical, chemical, and biological similarities of these materials and provide substantive evidence to support their grouping and ability to read-across data as part of a food safety demonstration.
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Affiliation(s)
- Sahar H Pradhan
- Department of Environmental Science, Baylor University, One Bear Place #97266, Waco, TX 76798-7266, USA
| | - Marina R Mulenos
- Department of Environmental Science, Baylor University, One Bear Place #97266, Waco, TX 76798-7266, USA
| | - London R Steele
- Department of Environmental Science, Baylor University, One Bear Place #97266, Waco, TX 76798-7266, USA
| | - Matthew Gibb
- Institute of Biomedical Studies, Baylor University, One Bear Place #97266, Waco, TX 76798-7266, USA
| | - James D Ede
- Vireo Advisors, LLC, Boston, MA, 02130-4323, USA
| | | | | | - Christie M Sayes
- Department of Environmental Science, Baylor University, One Bear Place #97266, Waco, TX 76798-7266, USA
- Institute of Biomedical Studies, Baylor University, One Bear Place #97266, Waco, TX 76798-7266, USA
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11
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Affiliation(s)
- Jo Anne Shatkin
- Vireo Advisors, LLC, Boston, Massachusetts 02205, United States
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12
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Ong KJ, Ede JD, Pomeroy-Carter CA, Sayes CM, Mulenos MR, Shatkin JA. A 90-day dietary study with fibrillated cellulose in Sprague-Dawley rats. Toxicol Rep 2020; 7:174-182. [PMID: 32021807 PMCID: PMC6994281 DOI: 10.1016/j.toxrep.2020.01.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 01/02/2020] [Accepted: 01/04/2020] [Indexed: 12/31/2022] Open
Abstract
Novel forms of fibrillated cellulose offer improved attributes for use in foods. Conventional cellulose and many of its derivatives are already widely used as food additives and are authorized as safe for use in foods in many countries. However, novel forms have not yet been thoroughly investigated using standardized testing methods. This study assesses the 90-day dietary toxicity of fibrillated cellulose, as compared to a conventional cellulose, Solka Floc. Sprague Dawley rats were fed 2 %, 3 %, or 4 % fibrillated cellulose for 90 consecutive days, and parallel Solka Floc groups were used as controls. Survival, clinical observations, body weight, food consumption, ophthalmologic evaluations, hematology, serum chemistry, urinalysis, post-mortem anatomic pathology, and histopathology were monitored and performed. No adverse observations were noted in relation to the administration of fibrillated cellulose. Under the conditions of this study and based on the toxicological endpoints evaluated, the no-observed-adverse-effect level (NOAEL) for fibrillated cellulose was 2194.2 mg/kg/day (males) and 2666.6 mg/kg/day (females), corresponding to the highest dose tested (4 %) for male and female Sprague Dawley rats. These results demonstrate that fibrillated cellulose behaves similarly to conventional cellulose and raises no safety concerns when used as a food ingredient at these concentrations.
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Key Words
- % RET, percent reticulocyte
- 90-day subchronic study
- ABAS, absolute basophil
- AEOS, absolute eosinophil
- ALB, albumin
- ALKP, alkaline phosphatase
- ALT, alanine aminotransferase
- ALUC, absolute large unstained cell
- ALYM, absolute lymphocyte
- AMON, absolute monocyte
- ANEU, absolute neutrophil
- ANOVA, one-way analysis of variance
- ARET, absolute reticulocyte
- AST, aspartate aminotransferase
- BUN, urea nitrogen
- CAS, Chemical Abstracts Service
- CHOL, cholesterol
- CREAT, creatinine
- Cellulose
- DLS, dynamic light scattering
- EDXS, energy-dispersive X-ray spectroscopy
- EFSA, European Food Safety Authority
- FDA, U.S. Food and Drug Administration
- Fibrillated cellulose
- GLOB, globulin
- GLP, good laboratory practice
- GLU, glucose
- GRAS, generally recognized as safe
- HBG, hemoglobin
- HCT, hematocrit
- MCH, mean corpuscular cell hemoglobin
- MCHC, mean corpuscular cell hemoglobin concentration
- MCV, mean corpuscular cell volume
- NOAEL
- NOAEL, no-observed-adverse-effect level
- OECD 408
- OECD, Organisation for Economic Co-operation and Development
- Oral exposure
- PLT, platelet count
- RBC, red blood cell count
- RDW, red cell distribution width
- SCOGS, Select Committee on GRAS Substances
- SDH, sorbitol dehydrogenase
- SEM, scanning electron microscopy
- TBA, total bile acids
- TBIL, total bilirubin
- TEM, transmission electron microscopy
- TEMPO, 2,2,6,6-tetramethyl-piperidinyloxyl
- TP, total protein
- TRIG, triglycerides
- WBC, white blood cell count
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Affiliation(s)
| | - James D. Ede
- Vireo Advisors, LLC, Boston, MA 02130-4323, United States
| | | | - Christie M. Sayes
- Baylor University, Department of Environmental Science, One Bear Place #97266, Waco, TX 76798- 7266, United States
| | - Marina R. Mulenos
- Baylor University, Department of Environmental Science, One Bear Place #97266, Waco, TX 76798- 7266, United States
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Lin YJ, Shatkin JA, Kong F. Evaluating mucoadhesion properties of three types of nanocellulose in the gastrointestinal tract in vitro and ex vivo. Carbohydr Polym 2019; 210:157-166. [DOI: 10.1016/j.carbpol.2019.01.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 01/09/2019] [Accepted: 01/09/2019] [Indexed: 02/05/2023]
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Ede JD, Ong KJ, Goergen M, Rudie A, Pomeroy-Carter CA, Shatkin JA. Risk Analysis of Cellulose Nanomaterials by Inhalation: Current State of Science. Nanomaterials (Basel) 2019; 9:E337. [PMID: 30832338 PMCID: PMC6474143 DOI: 10.3390/nano9030337] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 01/31/2019] [Accepted: 02/23/2019] [Indexed: 01/04/2023]
Abstract
Cellulose nanomaterials (CNs) are emerging advanced materials with many unique properties and growing commercial significance. A life-cycle risk assessment and environmental health and safety roadmap identified potential risks from inhalation of powdered CNs in the workplace as a key gap in our understanding of safety and recommended addressing this data gap to advance the safe and successful commercialization of these materials. Here, we (i) summarize the currently available published literature for its contribution to our current understanding of CN inhalation hazard and (ii) evaluate the quality of the studies for risk assessment purposes using published study evaluation tools for nanomaterials to assess the weight of evidence provided. Our analysis found that the quality of the available studies is generally inadequate for risk assessment purposes but is improving over time. There have been some advances in knowledge about the effects of short-term inhalation exposures of CN. The most recent in vivo studies suggest that short-term exposure to CNs results in transient inflammation, similarly to other poorly soluble, low toxicity dusts such as conventional cellulose, but is markedly different from fibers with known toxicity such as certain types of multiwalled carbon nanotubes or asbestos. However, several data gaps remain, and there is still a lack of understanding of the effects from long-term, low-dose exposures that represent realistic workplace conditions, essential for a quantitative assessment of potential health risk. Therefore, taking precautions when handling dry forms of CNs to avoid dust inhalation exposure is warranted.
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Affiliation(s)
- James D Ede
- Vireo Advisors, LLC, Boston, MA 02130-4323, USA.
| | | | - Michael Goergen
- P3Nano, U.S. Endowment for Forestry and Communities, Greenville, SC 29601, USA.
| | - Alan Rudie
- Forest Products Laboratory, USDA Forest Service, Madison, WI 53726-2398, USA.
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Roberts R, Gettz K, Stebounova LV, Anne Shatkin J, Peters T, Johan Foster E. Collection of airborne ultrafine cellulose nanocrystals by impinger with an efficiency mimicking deposition in the human respiratory system. J Occup Environ Hyg 2019; 16:141-150. [PMID: 30427281 DOI: 10.1080/15459624.2018.1540876] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
As cellulose nanocrystals (CNCs) are increasing in production, establishing safe workplace practices in industry will be paramount to their continued use and growth. Particles other than CNCs with similar high aspect ratios have exhibited toxicity on inhalation. Safeguards are needed to monitor concentrations of CNCs in air in industrial and laboratory settings to protect workers. However, because of their size, morphology, and chemical makeup, CNCs are difficult to characterize and differentiate from other dust and cellulose products. This work is focused on developing an effective method of characterizing the concentration of airborne ultrafine CNCs that may deposit in the respiratory tract. CNCs were tagged with rhodamine b (RhB-CNCs) for improved visualization and characterized using UV-vis spectroscopy (UV-vis), transmission electron microscopy (TEM), and dynamic light scattering (DLS), then aerosolized and collected via a novel method using plastic impingers. Concentration of RhB-CNCs was measured using UV-vis and scanning mobility particle sizer (SMPS). The plastic impinger with 3D-printed nozzle collected airborne CNCs at an efficiency that improves upon commercially available impingers for relevant particle sizes.
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Affiliation(s)
- Rose Roberts
- a Virginia Polytechnic Institute and State University - Materials Science and Engineering , Blacksburg , Virginia , United States
| | - Kevin Gettz
- b University of Iowa - Department of Occupational and Environmental Health , Iowa City , Iowa , United States
| | - Larissa V Stebounova
- b University of Iowa - Department of Occupational and Environmental Health , Iowa City , Iowa , United States
| | - Jo Anne Shatkin
- c Vireo Advisors, LLC , Boston , Massachusetts , United States
| | - Thomas Peters
- b University of Iowa - Department of Occupational and Environmental Health , Iowa City , Iowa , United States
| | - E Johan Foster
- a Virginia Polytechnic Institute and State University - Materials Science and Engineering , Blacksburg , Virginia , United States
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Foster EJ, Moon RJ, Agarwal UP, Bortner MJ, Bras J, Camarero-Espinosa S, Chan KJ, Clift MJD, Cranston ED, Eichhorn SJ, Fox DM, Hamad WY, Heux L, Jean B, Korey M, Nieh W, Ong KJ, Reid MS, Renneckar S, Roberts R, Shatkin JA, Simonsen J, Stinson-Bagby K, Wanasekara N, Youngblood J. Current characterization methods for cellulose nanomaterials. Chem Soc Rev 2018; 47:2609-2679. [PMID: 29658545 DOI: 10.1039/c6cs00895j] [Citation(s) in RCA: 354] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A new family of materials comprised of cellulose, cellulose nanomaterials (CNMs), having properties and functionalities distinct from molecular cellulose and wood pulp, is being developed for applications that were once thought impossible for cellulosic materials. Commercialization, paralleled by research in this field, is fueled by the unique combination of characteristics, such as high on-axis stiffness, sustainability, scalability, and mechanical reinforcement of a wide variety of materials, leading to their utility across a broad spectrum of high-performance material applications. However, with this exponential growth in interest/activity, the development of measurement protocols necessary for consistent, reliable and accurate materials characterization has been outpaced. These protocols, developed in the broader research community, are critical for the advancement in understanding, process optimization, and utilization of CNMs in materials development. This review establishes detailed best practices, methods and techniques for characterizing CNM particle morphology, surface chemistry, surface charge, purity, crystallinity, rheological properties, mechanical properties, and toxicity for two distinct forms of CNMs: cellulose nanocrystals and cellulose nanofibrils.
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Affiliation(s)
- E Johan Foster
- Department of Materials Science and Engineering, Virginia Tech, 445 Old Turner St, 203 Holden Hall, Blacksburg, 24061, VA, USA.
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17
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Shatkin JA, Oberdörster G. Comment on Shvedova et al. (2016), "gender differences in murine pulmonary responses elicited by cellulose nanocrystals". Part Fibre Toxicol 2016; 13:59. [PMID: 27814761 PMCID: PMC5096324 DOI: 10.1186/s12989-016-0170-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 10/18/2016] [Indexed: 12/21/2022] Open
Abstract
A recent publication in “Particle and Fibre Toxicology” reported on the gender differences in pulmonary toxicity from oro-pharyngeal aspiration of a high dose of cellulose nanocrystals. The study is timely given the growing interest in diverse commercial applications of cellulose nanomaterials, and the need for studies addressing pulmonary toxicity. The results from this study are interesting and can be strengthened with a discussion of how differences in the weights of female and male C57BL/6 mice was accounted for. Without such a discussion, the observed differences could be partially explained by the lower body weights of females, resulting in higher doses than males when standardized to body weight or lung volume. Further, few conclusions can be drawn about the pulmonary toxicity of cellulose nanocrystals given the study design: examination of a single high dose of cellulose nanocrystals, administered as a bolus, without positive or negative controls or low dose comparisons, and at an unphysiological and high dose rate. Simulating the bolus type delivery by inhalation would require a highly unrealistic exposure concentration in the g/m3 range of extremely short duration. A discussion of these limitations is missing in the paper; further speculative comparisons of cellulose nanocrystals toxicity to asbestos and carbon nanotubes in the abstract are both unwarranted and can be misleading, these materials were neither mentioned in the manuscript, nor evaluated in the study.
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Affiliation(s)
| | - Günter Oberdörster
- University of Rochester, School of Medicine and Dentistry, Rochester, NY, USA
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18
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Shatkin JA, Ong KJ. Alternative Testing Strategies for Nanomaterials: State of the Science and Considerations for Risk Analysis. Risk Anal 2016; 36:1564-1580. [PMID: 27273523 DOI: 10.1111/risa.12642] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 03/02/2016] [Accepted: 04/19/2016] [Indexed: 06/06/2023]
Abstract
The rapid growth of the nanotechnology industry has warranted equal progress in the nanotoxicology and risk assessment fields. In vivo models have traditionally been used to determine human and environmental risk for chemicals; however, the use of these tests has limitations, and there are global appeals to develop reliable alternatives to animal testing. Many have investigated the use of alternative (nonanimal) testing methods and strategies have quickly developed and resulted in the generation of large toxicological data sets for numerous nanomaterials (NMs). Due to the novel physicochemical properties of NMs that are related to surface characteristics, the approach toward toxicity test development has distinct considerations from traditional chemicals, bringing new requirements for adapting these approaches for NMs. The methodical development of strategies that combine multiple alternative tests can be useful for predictive NM risk assessment and help screening-level decision making. This article provides an overview of the main developments in alternative methods and strategies for reducing uncertainty in NM risk assessment, including advantages and disadvantages of in vitro, ex vivo, and in silico methods, and examples of existing comprehensive strategies. In addition, knowledge gaps are identified toward improvements for experimental and strategy design, specifically highlighting the need to represent realistic exposure scenarios and to consider NM-specific concerns such as characterization, assay interferences, and standardization. Overall, this article aims to improve the reliability and utility of alternative testing methods and strategies for risk assessment of manufactured NMs.
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Affiliation(s)
| | - K J Ong
- Vireo Advisors, LLC, Boston, MA, USA
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19
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Shatkin JA. Introduction to Special Series. Risk Anal 2016; 36:1518-1519. [PMID: 27575258 DOI: 10.1111/risa.12696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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20
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Shatkin JA, Ong KJ, Beaudrie C, Clippinger AJ, Hendren CO, Haber LT, Hill M, Holden P, Kennedy AJ, Kim B, MacDonell M, Powers CM, Sharma M, Sheremeta L, Stone V, Sultan Y, Turley A, White RH. Advancing Risk Analysis for Nanoscale Materials: Report from an International Workshop on the Role of Alternative Testing Strategies for Advancement. Risk Anal 2016; 36:1520-1537. [PMID: 27510619 DOI: 10.1111/risa.12683] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 07/07/2016] [Accepted: 07/07/2016] [Indexed: 06/06/2023]
Abstract
The Society for Risk Analysis (SRA) has a history of bringing thought leadership to topics of emerging risk. In September 2014, the SRA Emerging Nanoscale Materials Specialty Group convened an international workshop to examine the use of alternative testing strategies (ATS) for manufactured nanomaterials (NM) from a risk analysis perspective. Experts in NM environmental health and safety, human health, ecotoxicology, regulatory compliance, risk analysis, and ATS evaluated and discussed the state of the science for in vitro and other alternatives to traditional toxicology testing for NM. Based on this review, experts recommended immediate and near-term actions that would advance ATS use in NM risk assessment. Three focal areas-human health, ecological health, and exposure considerations-shaped deliberations about information needs, priorities, and the next steps required to increase confidence in and use of ATS in NM risk assessment. The deliberations revealed that ATS are now being used for screening, and that, in the near term, ATS could be developed for use in read-across or categorization decision making within certain regulatory frameworks. Participants recognized that leadership is required from within the scientific community to address basic challenges, including standardizing materials, protocols, techniques and reporting, and designing experiments relevant to real-world conditions, as well as coordination and sharing of large-scale collaborations and data. Experts agreed that it will be critical to include experimental parameters that can support the development of adverse outcome pathways. Numerous other insightful ideas for investment in ATS emerged throughout the discussions and are further highlighted in this article.
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Affiliation(s)
| | | | | | | | | | | | | | - Patricia Holden
- UC Santa Barbara, Bren School of Environmental Science & Management, ERI, and UC CEIN, University of California, Santa Barbara, CA, USA
| | - Alan J Kennedy
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, USA
| | | | - Margaret MacDonell
- Argonne National Laboratory, Environmental Science Division, Argonne, IL, USA
| | - Christina M Powers
- U.S. Environmental Protection Agency, Office of Air and Radiation, Office of Transportation and Air Quality, Ann Arbor, MI, USA
| | - Monita Sharma
- PETA International Science Consortium Ltd, London, UK
| | | | - Vicki Stone
- John Muir Building Gait 1 Heriot-Watt University, Edinburgh, Scotland, UK
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Sharma M, Shatkin JA, Cairns C, Canady R, Clippinger AJ. Framework to Evaluate Exposure Relevance and Data Needs for Risk Assessment of Nanomaterials using in Vitro Testing Strategies. Risk Anal 2016; 36:1551-1563. [PMID: 26905487 DOI: 10.1111/risa.12581] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This article presents a multistage framework for evaluating the strength of evidence of nanomaterial (NM) exposure characterization data to optimize the utility of in vitro testing strategies for human health risk assessment. This framework is intended to aid risk assessors in evaluating the relevance of data from in vitro tests and to optimize the development of new in vitro testing strategies. The initial stage frames the exposure scenarios of interest in advance of testing to incorporate aspects such as release points, route of exposure, biological and environmental transformations, dose metrics, and biological targets in subsequent stages. The second stage considers characterization in the context of a realistic exposure and the third stage involves designing a testing strategy based on expected exposure conditions. For the fourth and final stage, we propose a matrix approach to evaluate the strength of evidence obtained in the first three stages as a basis for determining the best combination of test conditions and analytical methods available to characterize and measure exposure based on the NM type. This approach can also be used to evaluate existing data for their relevance to the expected exposure scenario and to further develop and optimize in vitro testing strategies. Implementation of the proposed strategy will generate meaningful information on NM properties and their interaction with biological systems, based on realistic exposure scenarios, which will be cost effective and can be applied for assessing risk and making intelligent regulatory decisions regarding the use and disposal of NMs.
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Affiliation(s)
- Monita Sharma
- PETA International Science Consortium Ltd, London, UK
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McClements DJ, DeLoid G, Pyrgiotakis G, Shatkin JA, Xiao H, Demokritou P. The Role of the Food Matrix and Gastrointestinal Tract in the assessment of biological properties of ingested engineered nanomaterials (iENMs): State of the science and knowledge gaps. NanoImpact 2016; 3-4:47-57. [PMID: 29568810 PMCID: PMC5860850 DOI: 10.1016/j.impact.2016.10.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Many foods contain appreciable levels of engineered nanomaterials (ENMs) (diameter < 100 nm) that may be either intentionally or unintentionally added. These ENMs vary considerably in their compositions, dimensions, morphologies, physicochemical properties, and biological responses. From a toxicological point of view, it is often convenient to classify ingested ENMs (iENMs) as being either inorganic (such as TiO2, SiO2, Fe2O3, or Ag) or organic (such as lipid, protein, or carbohydrate), since the former tend to be indigestible and the latter are generally digestible. At present there is a relatively poor understanding of how different types of iENMs behave within the human gastrointestinal tract (GIT), and how the food matrix and biopolymers transform their physico-chemical properties and influence their gastrointestinal fate. This lack of knowledge confounds an understanding of their potential harmful effects on human health. The purpose of this article is to review our current understanding of the GIT fate of iENMs, and to highlight gaps where further research is urgently needed in assessing potential risks and toxicological implications of iENMs. In particular, a strong emphasis is given to the development of standardized screening methods that can be used to rapidly and accurately assess the toxicological properties of iENMs.
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Affiliation(s)
- David Julian McClements
- Department of Food Science, University of Massachusetts Amherst, Amherst, MA 01003, USA
- corresponding authors: David Julian McClements, Department of Food Science, University of Massachusetts Amherst, Amherst, MA 01003, USA. ; Tel: 413 545 1019. Philip Demokritou, Center for Nanotechnology an nanotoxicology, T.H. Chan School of Public Health, Harvard University, Boston MA 02115, , Tel 617 432-3481, Web: www.hsph.harvard.edu/nano
| | - Glen DeLoid
- Laboratory for Environmental Health NanoScience (LEHNS), Center for Nanotechnology and Nanotoxicology, T. H. Chan School of Public Health, Harvard University, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Georgios Pyrgiotakis
- Laboratory for Environmental Health NanoScience (LEHNS), Center for Nanotechnology and Nanotoxicology, T. H. Chan School of Public Health, Harvard University, 665 Huntington Avenue, Boston, MA 02115, USA
| | | | - Hang Xiao
- Department of Food Science, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Philip Demokritou
- Laboratory for Environmental Health NanoScience (LEHNS), Center for Nanotechnology and Nanotoxicology, T. H. Chan School of Public Health, Harvard University, 665 Huntington Avenue, Boston, MA 02115, USA
- corresponding authors: David Julian McClements, Department of Food Science, University of Massachusetts Amherst, Amherst, MA 01003, USA. ; Tel: 413 545 1019. Philip Demokritou, Center for Nanotechnology an nanotoxicology, T.H. Chan School of Public Health, Harvard University, Boston MA 02115, , Tel 617 432-3481, Web: www.hsph.harvard.edu/nano
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Nowack B, David RM, Fissan H, Morris H, Shatkin JA, Stintz M, Zepp R, Brouwer D. Potential release scenarios for carbon nanotubes used in composites. Environ Int 2013; 59:1-11. [PMID: 23708563 DOI: 10.1016/j.envint.2013.04.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 04/03/2013] [Accepted: 04/16/2013] [Indexed: 06/02/2023]
Abstract
The expected widespread use of carbon nanotube (CNT)-composites in consumer products calls for an assessment of the possible release and exposure to workers, consumers and the environment. Release of CNTs may occur at all steps in the life cycle of products, but to date only limited information is available about release of CNTs from actual products and articles. As a starting point for exposure assessment, exploring sources and pathways of release helps to identify relevant applications and situations where the environment and especially humans may encounter releases of CNTs. It is the aim of this review to identify various potential release scenarios for CNTs used in polymers and identify the greatest likelihood of release at the various stages throughout the life-cycle of the product. The available information on release of CNTs from products and articles is reviewed in a first part. In a second part nine relevant release scenarios are described in detail: injection molding, manufacturing, sports equipment, electronics, windmill blades, fuel system components, tires, textiles, incineration, and landfills. Release from products can potentially occur by two pathways; (a) where free CNTs are released directly, or more frequently (b) where the initial release is a particle with CNTs embedded in the matrix, potentially followed by the subsequent release of CNTs from the matrix. The potential for release during manufacturing exists for all scenarios, however, this is also the situation when exposure can be best controlled. For most of the other life cycle stages and their corresponding release scenarios, potential release of CNTs can be considered to be low, but it cannot be excluded totally. Direct release to the environment is also considered to be very low for most scenarios except for the use of CNTs in tires where significant abrasion during use and release into the environment would occur. Also the possible future use of CNTs in textiles could result in consumer exposure. A possibility for significant release also exists during recycling operations when the polymers containing CNTs are handled together with other polymers and mainly occupational users would be exposed. It can be concluded that in general, significant release of CNTs from products and articles is unlikely except in manufacturing and subsequent processing, tires, recycling, and potentially in textiles. However except for high energy machining processes, most likely the resulting exposure for these scenarios will be low and to a non-pristine form of CNTs. Actual exposure studies, which quantify the amount of material released should be conducted to provide further evidence for this conclusion.
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Affiliation(s)
- Bernd Nowack
- Empa - Swiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, CH-9014 St Gallen, Switzerland.
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Nel AE, Nasser E, Godwin H, Avery D, Bahadori T, Bergeson L, Beryt E, Bonner JC, Boverhof D, Carter J, Castranova V, Deshazo JR, Hussain SM, Kane AB, Klaessig F, Kuempel E, Lafranconi M, Landsiedel R, Malloy T, Miller MB, Morris J, Moss K, Oberdorster G, Pinkerton K, Pleus RC, Shatkin JA, Thomas R, Tolaymat T, Wang A, Wong J. A multi-stakeholder perspective on the use of alternative test strategies for nanomaterial safety assessment. ACS Nano 2013; 7:6422-33. [PMID: 23924032 PMCID: PMC4004078 DOI: 10.1021/nn4037927] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
There has been a conceptual shift in toxicological studies from describing what happens to explaining how the adverse outcome occurs, thereby enabling a deeper and improved understanding of how biomolecular and mechanistic profiling can inform hazard identification and improve risk assessment. Compared to traditional toxicology methods, which have a heavy reliance on animals, new approaches to generate toxicological data are becoming available for the safety assessment of chemicals, including high-throughput and high-content screening (HTS, HCS). With the emergence of nanotechnology, the exponential increase in the total number of engineered nanomaterials (ENMs) in research, development, and commercialization requires a robust scientific approach to screen ENM safety in humans and the environment rapidly and efficiently. Spurred by the developments in chemical testing, a promising new toxicological paradigm for ENMs is to use alternative test strategies (ATS), which reduce reliance on animal testing through the use of in vitro and in silico methods such as HTS, HCS, and computational modeling. Furthermore, this allows for the comparative analysis of large numbers of ENMs simultaneously and for hazard assessment at various stages of the product development process and overall life cycle. Using carbon nanotubes as a case study, a workshop bringing together national and international leaders from government, industry, and academia was convened at the University of California, Los Angeles, to discuss the utility of ATS for decision-making analyses of ENMs. After lively discussions, a short list of generally shared viewpoints on this topic was generated, including a general view that ATS approaches for ENMs can significantly benefit chemical safety analysis.
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Affiliation(s)
- Andre E Nel
- Department of Medicine, Division of NanoMedicine, University of California Center for Environmental Implications of Nanotechnology, University of California, Los Angeles, California 90095, United States.
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Shatkin JA, Abbott LC, Bradley AE, Canady RA, Guidotti T, Kulinowski KM, Löfstedt RE, Louis G, MacDonell M, Maynard AD, Paoli G, Sheremeta L, Walker N, White R, Williams R. Nano risk analysis: advancing the science for nanomaterials risk management. Risk Anal 2010; 30:1680-1687. [PMID: 20846172 DOI: 10.1111/j.1539-6924.2010.01493.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Scientists, activists, industry, and governments have raised concerns about health and environmental risks of nanoscale materials. The Society for Risk Analysis convened experts in September 2008 in Washington, DC to deliberate on issues relating to the unique attributes of nanoscale materials that raise novel concerns about health risks. This article reports on the overall themes and findings of the workshop, uncovering the underlying issues for each of these topics that become recurring themes. The attributes of nanoscale particles and other nanomaterials that present novel issues for risk analysis are evaluated in a risk analysis framework, identifying challenges and opportunities for risk analysts and others seeking to assess and manage the risks from emerging nanoscale materials and nanotechnologies. Workshop deliberations and recommendations for advancing the risk analysis and management of nanotechnologies are presented.
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