Enhanced antibacterial effect of silver nanoparticles obtained by electrochemical synthesis in poly(amide-hydroxyurethane) media

Ștefan, Marius; Hrițcu, Lucian; Mihășan, Marius; Pricop, Daniela; Gostin, Irina; Olariu, Romeo Iulian; Dunca, Simona; Melnig, V.

doi:10.1007/s10856-011-4281-z

Cited by 37 publications

(16 citation statements)

References 24 publications

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“…On the other hand, treatment of exponentially growing bacteria with AgNPs for 3.5 hours (P. aeruginosa ATCC 9027) and 8 hours (S. aureus ATCC 6538P) caused major damage to the treated cells, seen as a disrupted and frayed cell envelope, with possible release of cellular contents ( Figure 6). The obtained results seemed to be consistent with the morphological changes observed by Marius et al, 42 who attributed their findings to clusters of AgNPs attaching onto the bacterial cell surface, probably inducing the formation of distinct perforations in the cell membrane, and ultimately resulting in cell lysis.…”

Section: Study Of Bacteria-killing Kineticssupporting

confidence: 91%

Green synthesis of silver nanoparticles using cranberry powder aqueous extract: characterization and antimicrobial properties

Ashour

Raafat

El‐Gowelli

et al. 2015

IJN

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Background The growing threat of microbial resistance against traditional antibiotics has prompted the development of several antimicrobial nanoparticles (NPs), including silver NPs (AgNPs). In this article, a simple and eco-friendly method for the synthesis of AgNPs using the cranberry powder aqueous extract is reported. Materials and methods Cranberry powder aqueous extracts (0.2%, 0.5%, and 0.8% w/v) were allowed to interact for 24 hours with a silver nitrate solution (10 mM) at 30°C at a ratio of 1:10. The formation of AgNPs was confirmed by ultraviolet-visible spectroscopy and their concentrations were determined using atomic absorption spectroscopy. The prepared NPs were evaluated by transmission electron microscopy, measurement of ζ-potential, and Fourier-transform infrared spectroscopy. The in vitro antimicrobial properties of AgNPs were then investigated against several microbial strains. Finally, in vivo appraisal of both wound-healing and antimicrobial properties of either plain AgNPs (prepared using 0.2% extract) or AgNP-Pluronic F-127 gel was conducted in a rat model after induction of a Staphylococcus aureus ATCC 6538P wound infection. Results The formation of AgNPs was confirmed by ultraviolet-visible spectroscopy, where a surface-plasmon resonance absorption peak was observed between 432 and 438 nm. Both size and concentration of the formed AgNPs increased with increasing concentration of the extracts. The developed NPs were stable, almost spherical, and polydisperse, with a size range of 1.4–8.6 nm. The negative ζ-potential values, as well as Fourier-transform infrared spectroscopy analysis, indicated the presence of a capping agent adsorbed onto the surface of the particles. In vitro antimicrobial evaluation revealed a size-dependent activity of the AgNPs against the tested organisms. Finally, AgNPs prepared using 0.2% extract exhibited a substantial in vivo healing potential for full-thickness excision wounds in rats. Conclusion AgNPs were successfully synthesized from a silver nitrate solution through a simple green route, using cranberry powder aqueous extract as a reducing as well as capping agent.

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Section: Study Of Bacteria-killing Kineticssupporting

confidence: 91%

Green synthesis of silver nanoparticles using cranberry powder aqueous extract: characterization and antimicrobial properties

Ashour

Raafat

El‐Gowelli

et al. 2015

IJN

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“…In the present study, we have assessed the bacterial behavior within 24 and 48 h following laser irradiation, and no relevant alterations in their growth were observed after 24 h. The 48 h period was considered because Marius et al 23 had reported that the species analyzed in their study showed growth capacity of up to 48 h, a fact not confirmed in our work, however. Therefore, our study demonstrated that the pattern of bacterial growth within the 24 h period was enough for analysis; therefore, it was not necessary to follow it over a longer period of time.…”

Section: Discussionmentioning

confidence: 71%

Blue Laser Inhibits Bacterial Growth of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa

Sousa

Santos

Gomes

et al. 2015

Photomedicine and Laser Surgery

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Objective: The purpose of this study was to analyze the influence of blue laser on bacterial growth of the main species that usually colonize cutaneous ulcers, as well as its effect over time following irradiation. Background data: The use of blue laser has been described as an adjuvant therapeutic method to inhibit bacterial growth, but there is no consensus about the best parameters to be used. Methods: Strains of Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, and Escherichia coli ATCC 25922 were suspended in saline solution at a concentration of 1.5 · 10 3 colony forming units (CFU)/mL. Next, 300 lL of this suspension was transferred to a microtitulation plate and exposed to a single blue laser irradiation (450 nm) at fluences of 0 (control), 3, 6, 12, 18, and 24 J/cm 2 . Each suspension was spread over the surface of a Petri plate before being incubated at 37°C, and counts of CFU were determined after 24 and 48 h. Results: Blue laser inhibited the growth of S. aureus and P. aeruginosa at fluences > 6 J/cm 2 . On the other hand, E. coli was inhibited at all fluences tested, except at 24 J/cm 2 . Conclusions: Blue laser light was capable of inhibiting bacterial growth at low fluences over time, thus presenting no time-dependent effect.

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“…These seemingly contradicting results can be explained by additional dissolution of AgNPs in the close vicinity of bacterial cell envelope upon cell-NP interaction. The importance of cell-NP contact has been also suggested and discussed previously [32], [33], [34]. Using E. coli , McQuillan et al [18] noticed that Ag + from AgNPs induced 2–3-fold up-regulation of Ag + -response genes copA , cueO and cusA compared to AgNO 3 and referred to this effect as “nanoparticle-enhanced silver ion stress”.…”

Section: Discussionmentioning

confidence: 85%

Particle-Cell Contact Enhances Antibacterial Activity of Silver Nanoparticles

et al. 2013

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BackgroundIt is generally accepted that antibacterial properties of Ag nanoparticles (AgNPs) are dictated by their dissolved fraction. However, dissolution-based concept alone does not fully explain the toxic potency of nanoparticulate silver compared to silver ions.Methodology/Principal FindingsHerein, we demonstrated that the direct contact between bacterial cell and AgNPs' surface enhanced the toxicity of nanosilver. More specifically, cell-NP contact increased the cellular uptake of particle-associated Ag ions – the single and ultimate cause of toxicity. To prove that, we evaluated the toxicity of three different AgNPs (uncoated, PVP-coated and protein-coated) to six bacterial strains: Gram-negative Escherichia coli, Pseudomonas fluorescens, P. putida and P. aeruginosa and Gram-positive Bacillus subtilis and Staphylococcus aureus. While the toxicity of AgNO3 to these bacteria varied only slightly (the 4-h EC50 ranged from 0.3 to 1.2 mg Ag/l), the 4-h EC50 values of protein-coated AgNPs for various bacterial strains differed remarkably, from 0.35 to 46 mg Ag/l. By systematically comparing the intracellular and extracellular free Ag+ liberated from AgNPs, we demonstrated that not only extracellular dissolution in the bacterial test environment but also additional dissolution taking place at the particle-cell interface played an essential role in antibacterial action of AgNPs. The role of the NP-cell contact in dictating the antibacterial activity of Ag-NPs was additionally proven by the following observations: (i) separation of bacterial cells from AgNPs by particle-impermeable membrane (cut-off 20 kDa, ∼4 nm) significantly reduced the toxicity of AgNPs and (ii) P. aeruginosa cells which tended to attach onto AgNPs, exhibited the highest sensitivity to all forms of nanoparticulate Ag.Conclusions/SignificanceOur findings provide new insights into the mode of antibacterial action of nanosilver and explain some discrepancies in this field, showing that “Ag-ion” and “particle-specific” mechanisms are not controversial but, rather, are two faces of the same coin.

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Enhanced antibacterial effect of silver nanoparticles obtained by electrochemical synthesis in poly(amide-hydroxyurethane) media

Cited by 37 publications

References 24 publications

Green synthesis of silver nanoparticles using cranberry powder aqueous extract: characterization and antimicrobial properties

Green synthesis of silver nanoparticles using cranberry powder aqueous extract: characterization and antimicrobial properties

Blue Laser Inhibits Bacterial Growth of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa

Particle-Cell Contact Enhances Antibacterial Activity of Silver Nanoparticles

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