The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform
Christie M Sayes - One of the best experts on this subject based on the ideXlab platform.
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A role for Nanoparticle surface reactivity in facilitating pulmonary toxicity and development of a base set of hazard assays as a component of Nanoparticle Risk management.
Inhalation toxicology, 2020Co-Authors: David B. Warheit, Kenneth L Reed, Christie M SayesAbstract:Results of some lung toxicology studies in rats indicate that pulmonary exposures to ultrafine or Nanoparticles produce enhanced inflammatory responses compared to fine-sized particles. Apart from particle size and corresponding surface area considerations, several additional factors may influence the lung toxicity of Nanoparticles. These include surface reactivity or surface treatments/coatings of particles, and aggregation potential of aerosolized particles. Conclusions from three pulmonary bioassay hazard/safety studies are summarized herein and demonstrate that particle surface characteristics such as chemical reactivity often correlate better with pulmonary toxicity than particle size or surface area considerations. In the first study, fine-sized quartz particle exposures in rats (500 nm) produced similar effects (inflammation, cytotoxicity, cell proliferation, and/or histopathology) compared to smaller 12-nm nanoscale quartz particles. In another study, no measurable differences in lung toxicity indices were quantified when comparing exposure effects in rats to (1) fine-sized TiO(2) particles (300 nm, 6 m(2)/g [surface area]); (2) TiO(2) nanodots (6-10 nm, 169 m(2)/g); or (3) TiO(2) nanorods (27 m(2)/g). In a third study, exposures to ultrafine TiO(2) particles of similar sizes and different surface areas produced differential degrees of toxicity--based in large part upon surface reactivity endpoints--rather than particle size or surface area indices. Finally, in a related issue for nanotechnology implications, a concept for developing a Risk assessment system for the development of new nanomaterials is presented. Embodied in a NanoRisk framework process, implementation of a base set of toxicity tests for evaluating the health and environmental hazards related to Nanoparticle exposures is discussed.
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a role for Nanoparticle surface reactivity in facilitating pulmonary toxicity and development of a base set of hazard assays as a component of Nanoparticle Risk management
Inhalation Toxicology, 2009Co-Authors: David B. Warheit, Kenneth L Reed, Christie M SayesAbstract:Results of some lung toxicology studies in rats indicate that pulmonary exposures to ultrafine or Nanoparticles produce enhanced inflammatory responses compared to fine-sized particles. Apart from particle size and corresponding surface area considerations, several additional factors may influence the lung toxicity of Nanoparticles. These include surface reactivity or surface treatments/coatings of particles, and aggregation potential of aerosolized particles. Conclusions from three pulmonary bioassay hazard/safety studies are summarized herein and demonstrate that particle surface characteristics such as chemical reactivity often correlate better with pulmonary toxicity than particle size or surface area considerations. In the first study, fine-sized quartz particle exposures in rats (500 nm) produced similar effects (inflammation, cytotoxicity, cell proliferation, and/or histopathology) compared to smaller 12-nm nanoscale quartz particles. In another study, no measurable differences in lung toxicity ind...
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development of a base set of toxicity tests using ultrafine tio2 particles as a component of Nanoparticle Risk management
Toxicology Letters, 2007Co-Authors: David B. Warheit, Robert A Hoke, C Finlay, E M Donner, Kenneth L Reed, Christie M SayesAbstract:Abstract The development of a Risk management system for nanoscale or ultrafine particle-types requires a base set of hazard data. Assessing Risk is a function of hazard and exposure data. Previously, we have suggested “parallel tracks” as a strategy for conducting Nanoparticle research. On the one hand, mechanistic studies on “representative” Nanoparticles could be supported by governmental agencies. Alternatively, with regard to commercial Nanoparticles, the environmental, health and safety (EHS) framework would include a minimum base set of toxicity studies which should be supported by the companies that are developing nano-based products. The minimum base set could include the following criteria: substantial particle characterization, pulmonary toxicity studies, acute dermal toxicity and sensitization studies, acute oral and ocular toxicity studies, along with screening type genotoxicity, and aquatic toxicity studies. We report here the toxicity results of a base set of hazard tests on a set of newly developed, well-characterized, ultrafine TiO 2 (uf-TiO 2 ) particle-types. In vivo pulmonary toxicity studies in rats demonstrated low inflammatory potential and lung tissue toxicity. Acute dermal irritation studies in rabbits and local lymph node assay results in mice indicated that uf-TiO 2 was not a skin irritant or dermal sensitizer. Acute oral toxicity studies demonstrated very low toxicity and uf-TiO 2 produced short-term and reversible ocular conjunctival redness in rabbits. Genotoxicity tests demonstrated that uf-TiO 2 was negative in both the bacterial reverse mutation test and in an in vitro mammalian chromosome aberration test with Chinese hamster ovary cells. The results of aquatic toxicity screening studies demonstrated that uf-TiO 2 exhibited low concern for aquatic hazard in unaerated, 48 h, static acute tests using the water flea, Daphnia magna ; exhibited low concern for aquatic hazard in unaerated, 96 h, static acute tests using the rainbow trout, Oncorhynchus mykiss ; and exhibited medium concern in a 72 h acute test using the green algae Pseudokirchneriella subcapitata. To summarize the findings, the results of most of the studies demonstrated low hazard potential in mammals or aquatic species following acute exposures to the ultrafine TiO 2 particle-types tested in this program.
Nikolaos Pantidos - One of the best experts on this subject based on the ideXlab platform.
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Biological Synthesis of Metallic Nanoparticles by Bacteria, Fungi andPlants
Journal of Nanomedicine & Nanotechnology, 2019Co-Authors: Nikolaos Pantidos, Louise HorsfallAbstract:Over the past few decades interest in metallic Nanoparticles and their synthesis has greatly increased. This has resulted in the development of numerous ways of producing metallic Nanoparticles using chemical and physical methods. However, drawbacks such as the involvement of toxic chemicals and the high-energy requirements of production make it difficult for them to be widely implemented. An alternative way of synthesising metallic Nanoparticles is by using living organisms such as bacteria, fungi and plants. This “green” method of biological Nanoparticle production is a promising approach that allows synthesis in aqueous conditions, with low energy requirements and low-costs. This review gives an overview of some of these environmentally friendly methods of biological metallic Nanoparticle synthesis. It also highlights the potential importance of these methods in assessing Nanoparticle Risk to both health and the environment.
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Biological Synthesis of Metallic Nanoparticles by Bacteria, Fungi and Plants
Journal of Nanomedicine & Nanotechnology, 2014Co-Authors: Nikolaos PantidosAbstract:Over the past few decades interest in metallic Nanoparticles and their synthesis has greatly increased. This has resulted in the development of numerous ways of producing metallic Nanoparticles using chemical and physical methods. However, drawbacks such as the involvement of toxic chemicals and the high-energy requirements of production make it difficult for them to be widely implemented. An alternative way of synthesising metallic Nanoparticles is by using living organisms such as bacteria, fungi and plants. This “green” method of biological Nanoparticle production is a promising approach that allows synthesis in aqueous conditions, with low energy requirements and low-costs. This review gives an overview of some of these environmentally friendly methods of biological metallic Nanoparticle synthesis. It also highlights the potential importance of these methods in assessing Nanoparticle Risk to both health and the environment.
David B. Warheit - One of the best experts on this subject based on the ideXlab platform.
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A role for Nanoparticle surface reactivity in facilitating pulmonary toxicity and development of a base set of hazard assays as a component of Nanoparticle Risk management.
Inhalation toxicology, 2020Co-Authors: David B. Warheit, Kenneth L Reed, Christie M SayesAbstract:Results of some lung toxicology studies in rats indicate that pulmonary exposures to ultrafine or Nanoparticles produce enhanced inflammatory responses compared to fine-sized particles. Apart from particle size and corresponding surface area considerations, several additional factors may influence the lung toxicity of Nanoparticles. These include surface reactivity or surface treatments/coatings of particles, and aggregation potential of aerosolized particles. Conclusions from three pulmonary bioassay hazard/safety studies are summarized herein and demonstrate that particle surface characteristics such as chemical reactivity often correlate better with pulmonary toxicity than particle size or surface area considerations. In the first study, fine-sized quartz particle exposures in rats (500 nm) produced similar effects (inflammation, cytotoxicity, cell proliferation, and/or histopathology) compared to smaller 12-nm nanoscale quartz particles. In another study, no measurable differences in lung toxicity indices were quantified when comparing exposure effects in rats to (1) fine-sized TiO(2) particles (300 nm, 6 m(2)/g [surface area]); (2) TiO(2) nanodots (6-10 nm, 169 m(2)/g); or (3) TiO(2) nanorods (27 m(2)/g). In a third study, exposures to ultrafine TiO(2) particles of similar sizes and different surface areas produced differential degrees of toxicity--based in large part upon surface reactivity endpoints--rather than particle size or surface area indices. Finally, in a related issue for nanotechnology implications, a concept for developing a Risk assessment system for the development of new nanomaterials is presented. Embodied in a NanoRisk framework process, implementation of a base set of toxicity tests for evaluating the health and environmental hazards related to Nanoparticle exposures is discussed.
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Rationale of genotoxicity testing of nanomaterials: regulatory requirements and appropriateness of available OECD test guidelines.
Nanotoxicology, 2010Co-Authors: David B. Warheit, E. Maria DonnerAbstract:AbstractThe development of an environmental health and safety Risk management system for nanoscale particle-types requires a base set of hazard data. Accurate determination of health and environmental Risks of nanomaterials is a function of the integration of hazard and exposure datasets. Recently, a Nanoparticle Risk assessment strategy was promulgated and the components are described in a document entitled “NanoRisk framework” (www.nanoRiskframework.com). A major component of the hazard evaluation includes a proposed minimum base set of toxicity studies. Included in the suggested studies were substantial particle characterization, a variety of acute hazard and environmental tests, concomitant with screening-type genotoxicity studies. The implementation of well-accepted genotoxicity assays for testing nanomaterials remains a controversial issue. This is because many of these genotoxicity tests were designed for screening general macroparticle chemicals and might not be suitable for the screening of nanom...
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a role for Nanoparticle surface reactivity in facilitating pulmonary toxicity and development of a base set of hazard assays as a component of Nanoparticle Risk management
Inhalation Toxicology, 2009Co-Authors: David B. Warheit, Kenneth L Reed, Christie M SayesAbstract:Results of some lung toxicology studies in rats indicate that pulmonary exposures to ultrafine or Nanoparticles produce enhanced inflammatory responses compared to fine-sized particles. Apart from particle size and corresponding surface area considerations, several additional factors may influence the lung toxicity of Nanoparticles. These include surface reactivity or surface treatments/coatings of particles, and aggregation potential of aerosolized particles. Conclusions from three pulmonary bioassay hazard/safety studies are summarized herein and demonstrate that particle surface characteristics such as chemical reactivity often correlate better with pulmonary toxicity than particle size or surface area considerations. In the first study, fine-sized quartz particle exposures in rats (500 nm) produced similar effects (inflammation, cytotoxicity, cell proliferation, and/or histopathology) compared to smaller 12-nm nanoscale quartz particles. In another study, no measurable differences in lung toxicity ind...
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development of a base set of toxicity tests using ultrafine tio2 particles as a component of Nanoparticle Risk management
Toxicology Letters, 2007Co-Authors: David B. Warheit, Robert A Hoke, C Finlay, E M Donner, Kenneth L Reed, Christie M SayesAbstract:Abstract The development of a Risk management system for nanoscale or ultrafine particle-types requires a base set of hazard data. Assessing Risk is a function of hazard and exposure data. Previously, we have suggested “parallel tracks” as a strategy for conducting Nanoparticle research. On the one hand, mechanistic studies on “representative” Nanoparticles could be supported by governmental agencies. Alternatively, with regard to commercial Nanoparticles, the environmental, health and safety (EHS) framework would include a minimum base set of toxicity studies which should be supported by the companies that are developing nano-based products. The minimum base set could include the following criteria: substantial particle characterization, pulmonary toxicity studies, acute dermal toxicity and sensitization studies, acute oral and ocular toxicity studies, along with screening type genotoxicity, and aquatic toxicity studies. We report here the toxicity results of a base set of hazard tests on a set of newly developed, well-characterized, ultrafine TiO 2 (uf-TiO 2 ) particle-types. In vivo pulmonary toxicity studies in rats demonstrated low inflammatory potential and lung tissue toxicity. Acute dermal irritation studies in rabbits and local lymph node assay results in mice indicated that uf-TiO 2 was not a skin irritant or dermal sensitizer. Acute oral toxicity studies demonstrated very low toxicity and uf-TiO 2 produced short-term and reversible ocular conjunctival redness in rabbits. Genotoxicity tests demonstrated that uf-TiO 2 was negative in both the bacterial reverse mutation test and in an in vitro mammalian chromosome aberration test with Chinese hamster ovary cells. The results of aquatic toxicity screening studies demonstrated that uf-TiO 2 exhibited low concern for aquatic hazard in unaerated, 48 h, static acute tests using the water flea, Daphnia magna ; exhibited low concern for aquatic hazard in unaerated, 96 h, static acute tests using the rainbow trout, Oncorhynchus mykiss ; and exhibited medium concern in a 72 h acute test using the green algae Pseudokirchneriella subcapitata. To summarize the findings, the results of most of the studies demonstrated low hazard potential in mammals or aquatic species following acute exposures to the ultrafine TiO 2 particle-types tested in this program.
Jürgen Schnekenburger - One of the best experts on this subject based on the ideXlab platform.
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current in vitro methods in Nanoparticle Risk assessment limitations and challenges
European Journal of Pharmaceutics and Biopharmaceutics, 2009Co-Authors: Alexandra Kroll, Mike H. Pillukat, Daniela Hahn, Jürgen SchnekenburgerAbstract:Nanoparticles are an emerging class of functional materials defined by size-dependent properties. Application fields range from medical imaging, new drug delivery technologies to various industrial products. Due to the expanding use of Nanoparticles, the Risk of human exposure rapidly increases and reliable toxicity test systems are urgently needed. Currently, Nanoparticle cytotoxicity testing is based on in vitro methods established for hazard characterization of chemicals. However, evidence is accumulating that Nanoparticles differ largely from these materials and may interfere with commonly used test systems. Here, we present an overview of current in vitro toxicity test methods for Nanoparticle Risk assessment and focus on their limitations resulting from specific Nanoparticle properties. Nanoparticle features such as high adsorption capacity, hydrophobicity, surface charge, optical and magnetic properties, or catalytic activity may interfere with assay components or detection systems, which has to be considered in Nanoparticle toxicity studies by characterization of specific particle properties and a careful test system validation. Future studies require well-characterized materials, the use of available reference materials and an extensive characterization of the applicability of the test methods employed. The resulting challenge for Nanoparticle toxicity testing is the development of new standardized in vitro methods that cannot be affected by Nanoparticle properties.
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Current in vitro methods in Nanoparticle Risk assessment: Limitations and challenges
European Journal of Pharmaceutics and Biopharmaceutics, 2009Co-Authors: Andreas Kroll, Mike H. Pillukat, Daniela Hahn, Jürgen SchnekenburgerAbstract:Nanoparticles are an emerging class of functional materials defined by size-dependent properties. Application fields range from medical imaging, new drug delivery technologies to various industrial products. Due to the expanding use of Nanoparticles, the Risk of human exposure rapidly increases and reliable toxicity test systems are urgently needed. Currently, Nanoparticle cytotoxicity testing is based on in vitro methods established for hazard characterization of chemicals. However, evidence is accumulating that Nanoparticles differ largely from these materials and may interfere with commonly used test systems. Here, we present an overview of current in vitro toxicity test methods for Nanoparticle Risk assessment and focus on their limitations resulting from specific Nanoparticle properties. Nanoparticle features such as high adsorption capacity, hydrophobicity, surface charge, optical and magnetic properties, or catalytic activity may interfere with assay components or detection systems, which has to be considered in Nanoparticle toxicity studies by characterization of specific particle properties and a careful test system validation. Future studies require well-characterized materials, the use of available reference materials and an extensive characterization of the applicability of the test methods employed. The resulting challenge for Nanoparticle toxicity testing is the development of new standardized in vitro methods that cannot be affected by Nanoparticle properties. © 2008 Elsevier B.V. All rights reserved.
Kenneth L Reed - One of the best experts on this subject based on the ideXlab platform.
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A role for Nanoparticle surface reactivity in facilitating pulmonary toxicity and development of a base set of hazard assays as a component of Nanoparticle Risk management.
Inhalation toxicology, 2020Co-Authors: David B. Warheit, Kenneth L Reed, Christie M SayesAbstract:Results of some lung toxicology studies in rats indicate that pulmonary exposures to ultrafine or Nanoparticles produce enhanced inflammatory responses compared to fine-sized particles. Apart from particle size and corresponding surface area considerations, several additional factors may influence the lung toxicity of Nanoparticles. These include surface reactivity or surface treatments/coatings of particles, and aggregation potential of aerosolized particles. Conclusions from three pulmonary bioassay hazard/safety studies are summarized herein and demonstrate that particle surface characteristics such as chemical reactivity often correlate better with pulmonary toxicity than particle size or surface area considerations. In the first study, fine-sized quartz particle exposures in rats (500 nm) produced similar effects (inflammation, cytotoxicity, cell proliferation, and/or histopathology) compared to smaller 12-nm nanoscale quartz particles. In another study, no measurable differences in lung toxicity indices were quantified when comparing exposure effects in rats to (1) fine-sized TiO(2) particles (300 nm, 6 m(2)/g [surface area]); (2) TiO(2) nanodots (6-10 nm, 169 m(2)/g); or (3) TiO(2) nanorods (27 m(2)/g). In a third study, exposures to ultrafine TiO(2) particles of similar sizes and different surface areas produced differential degrees of toxicity--based in large part upon surface reactivity endpoints--rather than particle size or surface area indices. Finally, in a related issue for nanotechnology implications, a concept for developing a Risk assessment system for the development of new nanomaterials is presented. Embodied in a NanoRisk framework process, implementation of a base set of toxicity tests for evaluating the health and environmental hazards related to Nanoparticle exposures is discussed.
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a role for Nanoparticle surface reactivity in facilitating pulmonary toxicity and development of a base set of hazard assays as a component of Nanoparticle Risk management
Inhalation Toxicology, 2009Co-Authors: David B. Warheit, Kenneth L Reed, Christie M SayesAbstract:Results of some lung toxicology studies in rats indicate that pulmonary exposures to ultrafine or Nanoparticles produce enhanced inflammatory responses compared to fine-sized particles. Apart from particle size and corresponding surface area considerations, several additional factors may influence the lung toxicity of Nanoparticles. These include surface reactivity or surface treatments/coatings of particles, and aggregation potential of aerosolized particles. Conclusions from three pulmonary bioassay hazard/safety studies are summarized herein and demonstrate that particle surface characteristics such as chemical reactivity often correlate better with pulmonary toxicity than particle size or surface area considerations. In the first study, fine-sized quartz particle exposures in rats (500 nm) produced similar effects (inflammation, cytotoxicity, cell proliferation, and/or histopathology) compared to smaller 12-nm nanoscale quartz particles. In another study, no measurable differences in lung toxicity ind...
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development of a base set of toxicity tests using ultrafine tio2 particles as a component of Nanoparticle Risk management
Toxicology Letters, 2007Co-Authors: David B. Warheit, Robert A Hoke, C Finlay, E M Donner, Kenneth L Reed, Christie M SayesAbstract:Abstract The development of a Risk management system for nanoscale or ultrafine particle-types requires a base set of hazard data. Assessing Risk is a function of hazard and exposure data. Previously, we have suggested “parallel tracks” as a strategy for conducting Nanoparticle research. On the one hand, mechanistic studies on “representative” Nanoparticles could be supported by governmental agencies. Alternatively, with regard to commercial Nanoparticles, the environmental, health and safety (EHS) framework would include a minimum base set of toxicity studies which should be supported by the companies that are developing nano-based products. The minimum base set could include the following criteria: substantial particle characterization, pulmonary toxicity studies, acute dermal toxicity and sensitization studies, acute oral and ocular toxicity studies, along with screening type genotoxicity, and aquatic toxicity studies. We report here the toxicity results of a base set of hazard tests on a set of newly developed, well-characterized, ultrafine TiO 2 (uf-TiO 2 ) particle-types. In vivo pulmonary toxicity studies in rats demonstrated low inflammatory potential and lung tissue toxicity. Acute dermal irritation studies in rabbits and local lymph node assay results in mice indicated that uf-TiO 2 was not a skin irritant or dermal sensitizer. Acute oral toxicity studies demonstrated very low toxicity and uf-TiO 2 produced short-term and reversible ocular conjunctival redness in rabbits. Genotoxicity tests demonstrated that uf-TiO 2 was negative in both the bacterial reverse mutation test and in an in vitro mammalian chromosome aberration test with Chinese hamster ovary cells. The results of aquatic toxicity screening studies demonstrated that uf-TiO 2 exhibited low concern for aquatic hazard in unaerated, 48 h, static acute tests using the water flea, Daphnia magna ; exhibited low concern for aquatic hazard in unaerated, 96 h, static acute tests using the rainbow trout, Oncorhynchus mykiss ; and exhibited medium concern in a 72 h acute test using the green algae Pseudokirchneriella subcapitata. To summarize the findings, the results of most of the studies demonstrated low hazard potential in mammals or aquatic species following acute exposures to the ultrafine TiO 2 particle-types tested in this program.
