Discriminatory antibacterial effects of calix[n]arene capped silver nanoparticles with regard to Gram positive and Gram negative bacteria

2013 ◽  
Vol 49 (64) ◽  
pp. 7150 ◽  
Author(s):  
Samira Boudebbouze ◽  
Anthony W. Coleman ◽  
Yannick Tauran ◽  
Hela Mkaouar ◽  
Florent Perret ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Gram Negative Bacteria ◽  
Antibacterial Effects ◽  
Gram Positive ◽  
Gram Negative

scholarly journals Biogenic Silver Nanoparticles Conjugated with Nisin: Improving the Antimicrobial and Antibiofilm Properties of Nanomaterials

Chemistry ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 1271-1285
Author(s):  
Patricia Zimet ◽  
Ruby Valadez ◽  
Sofía Raffaelli ◽  
María Belén Estevez ◽  
Helena Pardo ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antimicrobial Properties ◽  
Value Added ◽  
Green Technology ◽  
Natural Food ◽  
Antibiofilm Activity ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Biogenic Silver Nanoparticles

Microbial technology offers a green alternative for the synthesis of value-added nanomaterials. In particular, fungal compounds can improve silver nanoparticle production, stabilizing colloidal nanoparticles. Based on a previous study by our group, silver nanoparticles obtained using the extracellular cell-free extracts of Phanerochaete chrysosporium (PchNPs) have shown antimicrobial and antibiofilm activity against Gram-negative bacteria. Moreover, nisin—a bacteriocin widely used as a natural food preservative—has recently gained much attention due its antimicrobial action against Gram-positive bacteria in biomedical applications. Therefore, the aim of this work was to conjugate biogenic silver nanoparticles (PchNPs) with nisin to obtain nanoconjugates (PchNPs@nis) with enhanced antimicrobial properties. Characterization assays were conducted to determine physicochemical properties of PchNPs@nis, and also their antibacterial and antibiofilm activities were studied. The formation of PchNPs@nis was confirmed by UV-Vis, TEM, and Raman spectroscopy analysis. Different PchNPs@nis nanobioconjugates showed diameter values in the range of 60–130 nm by DLS and surface charge values between −20 and −13 mV. Nisin showed an excellent affinity to PchNPs, with binding efficiencies higher than 75%. Stable synthesized PchNPs@nis nanobioconjugates were not only able to inhibit biofilm formation by S. aureus, but also showed inhibition of the planktonic cell growth of Staphyloccocus aureus and Escherichia coli, broadening the spectrum of action of the unconjugated antimicrobials against Gram-positive and Gram-negative bacteria. In conclusion, these results show the promising application of PchNPs@nis, prepared via green technology, as potential antimicrobial nanomaterials.

Synthesis of silver nanoparticles colloids in imidazolium halide ionic liquids and their antibacterial activities for gram-positive and gram-negative bacteria

Chemosphere ◽  
2020 ◽  
Vol 243 ◽  
pp. 125302 ◽  
Author(s):  
Virendra Patil ◽  
Swapnil Mahajan ◽  
Mohan Kulkarni ◽  
Kashinath Patil ◽  
Chandrashekhar Rode ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Ionic Liquids ◽  
Antibacterial Activities ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative

scholarly journals SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF SILVER NANOPARTICLES STABILIZED BY CITRATE ANIONS

2020 ◽  
Vol 2020 (60) ◽  
pp. 127-135
Author(s):  
Liliya BAZYLYAK ◽  
◽  
Andriy KYTSYA ◽  
Ilona KARPENKO ◽  
Olena KARPENKO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Cell Walls ◽  
Colloidal Silver ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Vis Spectroscopy

Widespread use of synthetic antimicrobial drugs leads to the development of antibiotic resistance of pathogenic strains of microorganisms. Therefore, today researchers are very interested in drugs based on nanoparticles of metals, in particular silver and copper, which have antibacterial, antifungal and antiviral activity. One of the reasons for the high interest of researchers in AgNPs as an antimicrobial agent is the significantly lower toxicity of AgNPs compared to Ag+ ions. High antibacterial efficiency of silver nano¬particles is achieved due to their developed surface, which provides maximum contact with the environment. In addition, such nanoparticles are quite small and are able to penetrate cell membranes, to affect intracellular processes from within. Therefore, the aim of this work was to obtain concentrated colloidal silver solutions stabilized by citrate anions, which simultaneously provide satisfactory stabilization of colloidal silver solutions and are non-toxic, as well as to investigate the antimicrobial action of synthesized AgNPs. The solution of citrate stabilized silver nanoparticles (AgNPs) have been obtained via the reaction of reduction of silver nitrate by hydrazine in alkaline medium in the presence of sodium citrate. AgNPs were investigated using transmission electron microscopy (TEM) and UV-vis spectroscopy and the particles size and particles size distribution (PSD) were determined. It was observed that obtained AgNPs are mainly spherical shape. It was found that the mean diameter and PSD of AgNPs determined using TEM and UV-vis spectroscopy are close and equal to 14 and 5 nm and 15 and 4 nm respectively. Obtained solution was concentrated by evaporation at 70 C under reduced pressure up to achievement of AgNPs concentration equal to 200 mg/L. On the base of comparison of optical properties of initial silver sol and concentrated solution the minority of agglomeration of AgNPs was statement. At the same time AgNO3 test showed no change of UV-vis spectrum of concentrate that points on the absence of reducing agent in the solution; this fact indicate that hydrazine was eliminated from during the evaporation of initial AgNPs solution and obtained concentrate did not consist the toxic impurities. Antimicrobial activity of obtained citrate stabilised AgNPs against Gram-positive Bacillus subtilis and Gram-negative Escherichia coli bacterium was tested using disk diffusion method. It was found that AgNPs shown significant bactericidal effect even at low (25 mg/L) concentration as well as some higher efficiency against Gram-negative bacterium. There was also a slightly higher antimicrobial activity of the drug against gram-negative bacteria Escherichia coli compared with gram-positive bacteria Bacillus subtilis, due to the different structure of cell walls. In particular, the walls of gram-positive bacteria consist mainly of peptidoglycan (murein), and gram-negative bacteria have cell walls with a layer of peptidoglycan and an outer membrane with a lipopolysaccharide component, which is not present in gram-positive bacteria. Based on the studies, it can be concluded that the proposed method of synthesis of AgNPs is suitable for obtaining highly concentrated silver sols. This method of synthesis is simple in hardware design, scalable, and the resulting colloidal solutions are stable and do not contain harmful impurities. Therefore, due to the high antibacterial activity of citrate-anion-stabilized AgNPs against certain types of gram-positive and gram-negative bacteria, it can be recommended for the manufacture of bactericidal drugs for biomedical purposes.

Antibacterial Activity of Glutathione-Coated Silver Nanoparticles against Gram Positive and Gram Negative Bacteria

Langmuir ◽  
2012 ◽  
Vol 28 (21) ◽  
pp. 8140-8148 ◽  
Author(s):  
Angelo Taglietti ◽  
Yuri A. Diaz Fernandez ◽  
Elvio Amato ◽  
Lucia Cucca ◽  
Giacomo Dacarro ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative

Synthesis, Characterization and Antibacterial Activity against Gram Positive and Gram Negative Bacteria of Biomimetically Coated Silver Nanoparticles

Langmuir ◽  
2011 ◽  
Vol 27 (15) ◽  
pp. 9165-9173 ◽  
Author(s):  
Elvio Amato ◽  
Yuri A. Diaz-Fernandez ◽  
Angelo Taglietti ◽  
Piersandro Pallavicini ◽  
Luca Pasotti ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative
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