Silver nanoparticles as antimicrobial agent: a case study on E. coli as a model for Gram-negative bacteria
01 Jul 2004-Journal of Colloid and Interface Science (J Colloid Interface Sci)-Vol. 275, Iss: 1, pp 177-182
TL;DR: These nontoxic nanomaterials, which can be prepared in a simple and cost-effective manner, may be suitable for the formulation of new types of bactericidal materials.
About: This article is published in Journal of Colloid and Interface Science.The article was published on 2004-07-01. It has received 5309 citations till now. The article focuses on the topics: Silver nanoparticle & Gram-negative bacteria.
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TL;DR: The 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 approximately 1-10 nm.
Abstract: 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 approximately 1-10 nm.
5,609 citations
TL;DR: Silver nanoparticles have emerged up with diverse medical applications ranging from silver based dressings, silver coated medicinal devices, such as nanogels, nanolotions, etc, due to its capability of modulating metals into their nanosize.
5,014 citations
TL;DR: The results suggest that Ag nanoparticles can be used as effective growth inhibitors in various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.
4,319 citations
Cites background or result from "Silver nanoparticles as antimicrobi..."
...In our results, Ag nanoparticles showed antimicrobial activity against yeast and E. coli (Figures 3 and 4) that was similar to that found by Sondi and Salopek-Sondi [17]....
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...coli (Figures 3 and 4) that was similar to that found by Sondi and Salopek-Sondi [17]....
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...coli during treatment with Ag nanoparticles [17]....
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...In contrast, Sondi and Salopek-Sondi [17] reported that the antimicrobial activity of silver nanoparticles on Gram-negative bacteria was dependent on the concentration of Ag nanoparticle, and was closely associated with the formation of dpitsT in the cell wall of bacteria....
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...Also, Sondi and Salopek-Sondi speculate that a similar mechanism may cause the degradation of the membrane structure of E. coli during treatment with Ag nanoparticles [17]....
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TL;DR: This is the first comparative study on the bactericidal properties of silver nanoparticles of different shapes, and the results demonstrate thatsilver nanoparticles undergo a shape-dependent interaction with the gram-negative organism E. coli.
Abstract: In this work we investigated the antibacterial properties of differently shaped silver nanoparticles against the gram-negative bacterium Escherichia coli, both in liquid systems and on agar plates. Energy-filtering transmission electron microscopy images revealed considerable changes in the cell membranes upon treatment, resulting in cell death. Truncated triangular silver nanoplates with a {111} lattice plane as the basal plane displayed the strongest biocidal action, compared with spherical and rod-shaped nanoparticles and with Ag+ (in the form of AgNO3). It is proposed that nanoscale size and the presence of a {111} plane combine to promote this biocidal property. To our knowledge, this is the first comparative study on the bactericidal properties of silver nanoparticles of different shapes, and our results demonstrate that silver nanoparticles undergo a shape-dependent interaction with the gram-negative organism E. coli.
3,697 citations
Cites background or result from "Silver nanoparticles as antimicrobi..."
...But a previous study (31) pointed out a distinct difference between these two methods....
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...It has been suggested (31) that disruption of membrane morphology may cause a significant increase in permeability, leading to uncontrolled transport through the plasma membrane and, finally, cell death....
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...Recent literature reports encouraging results about the bactericidal activity of silver nanoparticles of either a simple or composite nature (21, 31)....
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...Sondi and Salopek-Sondi (31) showed that interac- tion of these particles with intracellular substances from the lysed cells caused their coagulation and the particles were thrown out of the liquid system....
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...In a previous report (31) on the bactericidal activity of silver nanoparticles, it was shown that the interaction between silver nanoparticles and constituents of the bacterial membrane caused structural changes in and damage to membranes, finally leading to cell death....
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TL;DR: This review presents an overview of silver nanoparticles (Ag NPs) preparation by green synthesis approaches that have advantages over conventional methods involving chemical agents associated with environmental toxicity.
3,290 citations
References
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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
TL;DR: Highly luminescent semiconductor quantum dots (zinc sulfide-capped cadmium selenide) have been covalently coupled to biomolecules for use in ultrasensitive biological detection and these nanometer-sized conjugates are water-soluble and biocompatible.
Abstract: Highly luminescent semiconductor quantum dots (zinc sulfide-capped cadmium selenide) have been covalently coupled to biomolecules for use in ultrasensitive biological detection. In comparison with organic dyes such as rhodamine, this class of luminescent labels is 20 times as bright, 100 times as stable against photobleaching, and one-third as wide in spectral linewidth. These nanometer-sized conjugates are water-soluble and biocompatible. Quantum dots that were labeled with the protein transferrin underwent receptor-mediated endocytosis in cultured HeLa cells, and those dots that were labeled with immunomolecules recognized specific antibodies or antigens.
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TL;DR: The existence of elements of silver and sulfur in the electron-dense granules and cytoplasm detected by X-ray microanalysis suggested the antibacterial mechanism of silver: DNA lost its replication ability and the protein became inactivated after Ag(+) treatment.
Abstract: To investigate the mechanism of inhibition of silver ions on microorganisms, two strains of bacteria, namely Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), were treated with AgNO(3) and studied using combined electron microscopy and X-ray microanalysis. Similar morphological changes occurred in both E. coli and S. aureus cells after Ag(+) treatment. The cytoplasm membrane detached from the cell wall. A remarkable electron-light region appeared in the center of the cells, which contained condensed deoxyribonucleic acid (DNA) molecules. There are many small electron-dense granules either surrounding the cell wall or depositing inside the cells. The existence of elements of silver and sulfur in the electron-dense granules and cytoplasm detected by X-ray microanalysis suggested the antibacterial mechanism of silver: DNA lost its replication ability and the protein became inactivated after Ag(+) treatment. The slighter morphological changes of S. aureus compared with E. coli recommended a defense system of S. aureus against the inhibitory effects of Ag(+) ions.
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TL;DR: The in vivo fate of these systems, after intravascular or tumoral administration, is discussed, as well as the mechanism involved in tumor regression, and the application of nanoparticles in imaging for cancer diagnosis is focused on.
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TL;DR: Using QDs linked to immunoglobulin G and streptavidin to label the breast cancer marker Her2, to stain actin and microtubule fibers in the cytoplasm, and to detect nuclear antigens inside the nucleus indicate that QD-based probes can be very effective in cellular imaging and offer substantial advantages over organic dyes in multiplex target detection.
Abstract: Semiconductor quantum dots (QDs) are among the most promising emerging fluorescent labels for cellular imaging. However, it is unclear whether QDs, which are nanoparticles rather than small molecules, can specifically and effectively label molecular targets at a subcellular level. Here we have used QDs linked to immunoglobulin G (IgG) and streptavidin to label the breast cancer marker Her2 on the surface of fixed and live cancer cells, to stain actin and microtubule fibers in the cytoplasm, and to detect nuclear antigens inside the nucleus. All labeling signals are specific for the intended targets and are brighter and considerably more photostable than comparable organic dyes. Using QDs with different emission spectra conjugated to IgG and streptavidin, we simultaneously detected two cellular targets with one excitation wavelength. The results indicate that QD-based probes can be very effective in cellular imaging and offer substantial advantages over organic dyes in multiplex target detection.
2,509 citations