T. J. Berger, J. A. Spadaro, S. E. Chapin, and R. O. Becker
1 Orthopedic Research, Veterans Administration Hospital, Syracuse, New York 13210
The inhibitory and bactericidal concentrations of electrically generated silver ions were 10 to 100 times lower than for silver sulfadiazine. Effects on normal mammalian cells were minimal.
Agents Chemother. 1976 February; 9(2): 357-358
Copyright © 1976 American Society for Microbiology. All Rights Reserved.
T. J. Berger*, J. A. Spadaro, Richard Bierman, S. E. Chapin, and R. O. Becker
* Veterans Administration Hospital, Syracuse, New York 13210, Department of Orthopedics, State University of New York, Upstate Medical Center, Syracuse, New York 13210
A qualitative and quantitative investigation was undertaken to study the susceptibility of unicellular eucaryotic organisms (yeasts) to metallic cations generated by low levels of direct current. Results were characteristic of effects obtained previously using clinical and standard bacteria test organisms. The present study demonstrated that anodic silver (Ag+) at low direct currents had inhibitory and fungicidal properties. Broth dilution susceptibility tests were made on several species of Candida and one species of Torulopsis. Growth in all isolates was inhibited by concentrations of electrically generated silver ions between 0.5 and 4.7 µg/ml, and silver exhibited fungicidal properties at concentrations as low as 1.9 µg/ml. The inhibitory and fungicidal concentrations of electrically generated silver ions are lower than those reported for other silver compounds.
Antimicrob Agents Chemother. 1976 November; 10(5): 856-860
Copyright © 1976 American Society for Microbiology. All Rights Reserved
Bernd Nowack*†, Harald F. Krug†, and Murray Height‡
† EMPA - Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland
‡ HeiQ Materials AG, CH-5330 Bad Zurzach, Switzerland
Nanosilver is one nanomaterial that is currently under a lot of scrutiny. Much of the discussion is based on the assumption that nanosilver is something new that has not been seen until recently and that the advances in nanotechnology opened completely new application areas for silver. However, we show in this analysis that nanosilver in the form of colloidal silver has been used for more than 100 years and has been registered as a biocidal material in the United States since 1954. Fifty-three percent of the EPA-registered biocidal silver products likely contain nanosilver. Most of these nanosilver applications are silver-impregnated water filters, algicides, and antimicrobial additives that do not claim to contain nanoparticles. Many human health standards for silver are based on an analysis of argyria occurrence (discoloration of the skin, a cosmetic condition) from the 1930s and include studies that considered nanosilver materials. The environmental standards on the other hand are based on ionic silver and may need to be re-evaluated based on recent findings that most silver in the environment, regardless of the original silver form, is present in the form of small clusters or nanoparticles. The implications of this analysis for policy of nanosilver is that it would be a mistake for regulators to ignore the accumulated knowledge of our scientific and regulatory heritage in a bid to declare nanosilver materials as new chemicals, with unknown properties and automatically harmful simply on the basis of a change in nomenclature to the term “nano”.
Environ. Sci. Technol., 2011, 45 (4), pp 1177–1183
Publication Date (Web): January 10, 2011
Copyright © 2011 American Chemical Society
CASSection: History, Education, and Documentation
Jose L Elechiguerra1, Justin L Burt1, Jose R Morones1, Alejandra Camacho-Bragado2, Xiaoxia Gao2, Humberto H Lara3 and Miguel J Yacaman1,2*
* Corresponding author: Miguel J Yacaman email@example.com
1 Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
2 Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, USA
3 Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Nuevo León, Mexico
The interaction of nanoparticles with biomolecules and microorganisms is an expanding field of research. Within this field, an area that has been largely unexplored is the interaction of metal nanoparticles with viruses. In this work, we demonstrate that silver nanoparticles undergo a size-dependent interaction with HIV-1, with nanoparticles exclusively in the range of 1–10 nm attached to the virus. The regular spatial arrangement of the attached nanoparticles, the center-to-center distance between nanoparticles, and the fact that the exposed sulfur-bearing residues of the glycoprotein knobs would be attractive sites for nanoparticle interaction suggest that silver nanoparticles interact with the HIV-1 virus via preferential binding to the gp120 glycoprotein knobs. Due to this interaction, silver nanoparticles inhibit the virus from binding to host cells, as demonstrated in vitro.
The electronic version of this article is the complete one and can be found online at: http://www.jnanobiotechnology.com/content/3/1/6
Received: 28 March 2005
Accepted: 29 June 2005
Published: 29 June 2005
© 2005 Elechiguerra et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
A. Dror-Ehrea, , , H. Mamaneb, T. Belenkovac, G. Markovichc, A. Adina
a Department of Soil and Water Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
b School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978, Israel
c School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
Received 1 June 2009; Accepted 21 July 2009. Available online 28 July 2009.
Silver nanoparticles exhibit antibacterial properties via bacterial inactivation and growth inhibition. The mechanism is not yet completely understood. This work was aimed at elucidating the effect of silver nanoparticles on inactivation of Escherichia coli, by studying particle–particle interactions in aqueous suspensions. Stable, molecularly capped, positively or negatively charged silver nanoparticles were mixed at 1 to 60 µg mL-1 with suspended E. coli cells to examine their effect on inactivation of the bacteria. Gold nanoparticles with the same surfactant were used as a control, being of similar size but made up of a presumably inert metal. Log reduction of 5 log10 and complete inactivation were obtained with the silver nanoparticles while the gold nanoparticles did not show any inactivation ability. The effect of molecularly capped nanoparticles on E. coli survival was dependent on particle number. Log reduction of E. coli was associated with the ratio between the number of nanoparticles and the initial bacterial cell count. Electrostatic attraction or repulsion mechanisms in silver nanoparticle–E. coli cell interactions did not contribute to the inactivation process.
Journal of Physics: Conference Series Volume 304 Number 1
L Kvitek et al 2011 J. Phys.: Conf. Ser. 304 012029 doi:10.1088/1742-6596/304/1/012029
L Kvitek1, A Panacek1, R Prucek1, J Soukupova1, M Vanickova1, M Kolar2 and R Zboril1
The in vitro study of antibacterial activity of silver nanoparticles (NPs), prepared via modified Tollens process, revealed high antibacterial activity even at very low concentrations around several units of mg/L. These concentrations are comparable with concentrations of ionic silver revealing same antibacterial effect. However, such low concentrations of silver NPs did not show acute cytotoxicity to mammalian cells - this occurs at concentrations higher than 60 mg/L of silver, while the cytotoxic level of ionic silver is much more lower (approx. 1 mg/L). Moreover, the silver NPs exhibit lower acute ecotoxicity against the eukaryotic organisms such as Paramecium caudatum, Monoraphidium sp. and D. melanogaster. The silver NPs are toxic to these organisms at the concentrations higher than 30 mg/L of silver. On contrary, ionic silver retains its cytoxicity and ecotoxicity even at the concentration equal to 1 mg/L. The performed experiments demonstrate significantly lower toxicity of silver NPs against the eukaryotic organisms than against the prokaryotic organisms.
Nanotechnology Volume 16 Number 10
Jose Ruben Morones et al 2005 Nanotechnology 16 2346 doi:10.1088/0957-4484/16/10/059
Jose Ruben Morones1, Jose Luis Elechiguerra1, Alejandra Camacho2, Katherine Holt3, Juan B Kouri4, Jose Tapia Ramírez5 and Miguel Jose Yacaman1,2
Nanotechnology is expected to open new avenues to fight and prevent disease using atomic scale tailoring of materials. Among the most promising nanomaterials with antibacterial properties are metallic nanoparticles, which exhibit increased chemical activity due to their large surface to volume ratios and crystallographic surface structure. The study of bactericidal nanomaterials is particularly timely considering the recent increase of new resistant strains of bacteria to the most potent antibiotics. This has promoted research in the well known activity of silver ions and silver-based compounds, including silver nanoparticles. The present work studies the effect of silver nanoparticles in the range of 1–100 nm on Gram-negative bacteria using high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM). Our results indicate that the bactericidal properties of the nanoparticles are size dependent, since the only nanoparticles that present a direct interaction with the bacteria preferentially have a diameter of ~1–10 nm.
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