Towards a definition of inorganic nanoparticles from an environmental, health and safety perspective
TL;DR: It is argued that evidence for novel size-dependent properties alone, rather than particle size, should be the primary criterion in any definition of nanoparticles when making decisions about their regulation for environmental, health and safety reasons.
Abstract: The regulation of engineered nanoparticles requires a widely agreed definition of such particles. Nanoparticles are routinely defined as particles with sizes between about 1 and 100 nm that show properties that are not found in bulk samples of the same material. Here we argue that evidence for novel size-dependent properties alone, rather than particle size, should be the primary criterion in any definition of nanoparticles when making decisions about their regulation for environmental, health and safety reasons. We review the size-dependent properties of a variety of inorganic nanoparticles and find that particles larger than about 30 nm do not in general show properties that would require regulatory scrutiny beyond that required for their bulk counterparts.
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TL;DR: Recent development in nanotechnology for water and wastewater treatment is reviewed, covering candidate nanomaterials, properties and mechanisms that enable the applications, advantages and limitations as compared to existing processes, and barriers and research needs for commercialization.
1,744 citations
TL;DR: The bacteriostatic/bactericidal effect of AgNPs is found to be size and dose-dependent as determined by the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of silver nanoparticles against four bacterial strains.
Abstract: A systematic and detailed study for size-specific antibacterial efficacy of silver nanoparticles (AgNPs) synthesized using a co-reduction approach is presented here. Nucleation and growth kinetics during the synthesis process was precisely controlled and AgNPs of average size 5, 7, 10, 15, 20, 30, 50, 63, 85, and 100 nm were synthesized with good yield and monodispersity. We found the bacteriostatic/bactericidal effect of AgNPs to be size and dose-dependent as determined by the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of silver nanoparticles against four bacterial strains. Out of the tested strains, Escherichia coli MTCC 443 and Staphylococcus aureus NCIM 5201 were found to be the most and least sensitive strains regardless of AgNP size. For AgNPs with less than 10 nm size, the antibacterial efficacy was significantly enhanced as revealed through delayed bacterial growth kinetics, corresponding MIC/MBC values and disk diffusion tests. AgNPs of the smallest size, i.e., 5 nm demonstrated the best results and mediated the fastest bactericidal activity against all the tested strains compared to AgNPs having 7 nm and 10 nm sizes at similar bacterial concentrations. TEM analysis of AgNP treated bacterial cells showed the presence of AgNPs on the cell membrane, and AgNPs internalized within the cells.
1,366 citations
TL;DR: In this paper, the major transformation processes of Ag-NPs in various aqueous environments, particularly transformations of the metallic Ag cores caused by reactions with (in)organic ligands, and the effects of such transformations on physical and chemical stability and toxicity are discussed.
Abstract: Silver nanoparticles (Ag-NPs) readily transform in the environment, which modifies their properties and alters their transport, fate, and toxicity. It is essential to consider such transformations when assessing the potential environmental impact of Ag-NPs. This review discusses the major transformation processes of Ag-NPs in various aqueous environments, particularly transformations of the metallic Ag cores caused by reactions with (in)organic ligands, and the effects of such transformations on physical and chemical stability and toxicity. Thermodynamic arguments are used to predict what forms of oxidized silver will predominate in various environmental scenarios. Silver binds strongly to sulfur (both organic and inorganic) in natural systems (fresh and sea waters) as well as in wastewater treatment plants, where most Ag-NPs are expected to be concentrated and then released. Sulfidation of Ag-NPs results in a significant decrease in their toxicity due to the lower solubility of silver sulfide, potentiall...
1,310 citations
TL;DR: In this article, the intrinsic biochemical properties of reactive oxygen species (ROS) underlie the mechanisms that regulate various physiological functions of living organisms, and they play an essential role in regulating various physiological function.
Abstract: Reactive oxygen species (ROS) play an essential role in regulating various physiological functions of living organisms. The intrinsic biochemical properties of ROS, which underlie the mechanisms ne...
1,260 citations
TL;DR: Chemistries that Facilitate Nanotechnology Kim E. Sapsford,† W. Russ Algar, Lorenzo Berti, Kelly Boeneman Gemmill,‡ Brendan J. Casey,† Eunkeu Oh, Michael H. Stewart, and Igor L. Medintz .
Abstract: Chemistries that Facilitate Nanotechnology Kim E. Sapsford,† W. Russ Algar, Lorenzo Berti, Kelly Boeneman Gemmill,‡ Brendan J. Casey,† Eunkeu Oh, Michael H. Stewart, and Igor L. Medintz*,‡ †Division of Biology, Department of Chemistry and Materials Science, Office of Science and Engineering Laboratories, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, United States ‡Center for Bio/Molecular Science and Engineering Code 6900 and Division of Optical Sciences Code 5611, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States College of Science, George Mason University, 4400 University Drive, Fairfax, Virginia 22030, United States Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Sacramento, California 95817, United States Sotera Defense Solutions, Crofton, Maryland 21114, United States
1,169 citations
References
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TL;DR: A review of gold nanoparticles can be found in this article, where the most stable metal nanoparticles, called gold colloids (AuNPs), have been used for catalysis and biology applications.
Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346
11,752 citations
TL;DR: In this article, the authors focus on the properties of quantum dots and their ability to join the dots into complex assemblies creates many opportunities for scientific discovery, such as the ability of joining the dots to complex assemblies.
Abstract: Current research into semiconductor clusters is focused on the properties of quantum dots-fragments of semiconductor consisting of hundreds to many thousands of atoms-with the bulk bonding geometry and with surface states eliminated by enclosure in a material that has a larger band gap. Quantum dots exhibit strongly size-dependent optical and electrical properties. The ability to join the dots into complex assemblies creates many opportunities for scientific discovery.
10,737 citations
"Towards a definition of inorganic n..." refers background in this paper
...that favour the confinement of electrons and the existence of discrete electronic states that are virtually absent for larger particle...
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TL;DR: In this paper, the authors describe recent progress in the theory of nanoparticle optical properties, particularly methods for solving Maxwell's equations for light scattering from particles of arbitrary shape in a complex environment.
Abstract: The optical properties of metal nanoparticles have long been of interest in physical chemistry, starting with Faraday's investigations of colloidal gold in the middle 1800s. More recently, new lithographic techniques as well as improvements to classical wet chemistry methods have made it possible to synthesize noble metal nanoparticles with a wide range of sizes, shapes, and dielectric environments. In this feature article, we describe recent progress in the theory of nanoparticle optical properties, particularly methods for solving Maxwell's equations for light scattering from particles of arbitrary shape in a complex environment. Included is a description of the qualitative features of dipole and quadrupole plasmon resonances for spherical particles; a discussion of analytical and numerical methods for calculating extinction and scattering cross-sections, local fields, and other optical properties for nonspherical particles; and a survey of applications to problems of recent interest involving triangula...
9,086 citations
TL;DR: The establishment of principles and test procedures to ensure safe manufacture and use of nanomaterials in the marketplace is urgently required and achievable.
Abstract: Nanomaterials are engineered structures with at least one dimension of 100 nanometers or less. These materials are increasingly being used for commercial purposes such as fillers, opacifiers, catalysts, semiconductors, cosmetics, microelectronics, and drug carriers. Materials in this size range may approach the length scale at which some specific physical or chemical interactions with their environment can occur. As a result, their properties differ substantially from those bulk materials of the same composition, allowing them to perform exceptional feats of conductivity, reactivity, and optical sensitivity. Possible undesirable results of these capabilities are harmful interactions with biological systems and the environment, with the potential to generate toxicity. The establishment of principles and test procedures to ensure safe manufacture and use of nanomaterials in the marketplace is urgently required and achievable.
8,323 citations
Book•
01 Jun 1974
TL;DR: The Atlas of Electrochemical Equilibria in Aqueous solutions as discussed by the authors is the most complete and complete work on aqueous solvents, which includes a detailed description of the properties of the solvers.
Abstract: Environmental ChemistryAtlas D'équilibres Électrochimiques. Atlas of Electrochemical Equilibria in Aqueous Solutions. By Marcel Pourbaix. Translated by James A. Franklin, EtcElectrochemical ImpedanceAtlas of Electrochemical Equilibria in Aqueous SolutionsElectrochemical Techniques in Corrosion Science and EngineeringEffect of Mineral-OrganicMicroorganism Interactions on Soil and Freshwater EnvironmentsCorrosion EngineeringAtlas of Electrochemical Equilibria in Aqueous SolutionsHandbook of Corrosion DataSolved Problems in Electrochemistry for Universities and IndustryEquilibrium DiagramsCorrosionThe Aqueous Chemistry of Polonium and the Practical Application of its ThermochemistryElectrochemistry in TransitionCorrosion Tests and StandardsFundamentals of Electrochemical CorrosionAtlas of Electrochemical Equilibria in Aqueous SolutionsLectures on Electrochemical CorrosionAtlas of Electrochemical Equilibria in Aqueous SolutionElectrochemical and Optical Techniques for the Study and Monitoring of Metallic CorrosionAtlas of Electrochemical Equilibria in Aqueous SolutionsElectronics Packaging 3Atlas of Chemical and Electrochemical Equilibria in the Presence of a Gaseous PhaseElectrochemistry in Mineral and Metal Processing VATLAS OF ELECTROCHEMICAL EQUILIBRIA.Thermodynamics of Dilute Aqueous SolutionsAtlas of Chemical and Electrochemical Equilibria in the Presence of a Gaseous PhaseBiomaterialsCorrosion Mechanisms in Theory and PracticeAtlas d'équilibres électrochimiques. Atlas of electrochemical equilibria in aqueous solutions. By Marcel Pourbaix. Translated by James A. Franklin, etcAtlas of Electrochemical Equilibria in Aqueous SolutionsSilicon Nitride and Silicon Dioxide Thin Insulating FilmsElectrochemical Energy SystemsInorganic ChemistryThe DaguerreotypeStandard Potentials in Aqueous SolutionCorrosion Engineering and Cathodic Protection HandbookMicroelectronic Applications of Chemical Mechanical PlanarizationAtlas of Electrochemical Equilibria in Aqueous SolutionsAtlas of Electrochemical Equilibria in Aqueous Solutions
7,701 citations
"Towards a definition of inorganic n..." refers background in this paper
...The biological impacts of ZnO nanoparticles in vitro result from the release of Zn 2+ and Zn(OH) + ions, which are the dominant species in fresh water of moderate alkalinity and neutral p...
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