scholarly journals Nanoencapsulation of Silver-Based Antimicrobial Drugs

2014 ◽  
Vol 70 (a1) ◽  
pp. C1644-C1644
Author(s):  
Jacinthe Gagnon ◽  
Rachel Caruso ◽  
Katharina Fromm
Keyword(s):  
Silver Nanoparticles ◽  
Antimicrobial Agents ◽  
Cell Attachment ◽  
Alveolar Epithelial Cells ◽  
Ag Nps ◽  
Antimicrobial Drugs ◽  
Alveolar Epithelial ◽  
Low Cytotoxicity ◽  
The Stability ◽  
Silver Compounds

Implant-associated infections still remain an issue in medicine and can cause various medical complications. In order to ensure proper host-cell integration and biocompatibility to an implant, it is essential to prevent bacterial adhesion during the critical period of 6 hours after surgery. Moreover, as the implants are increasingly used in medicine, bacteria are becoming more resistant to antibiotics, in such a way that new developments in preventing and curing infections are more than ever needed. Silver compounds and nanoparticles are gaining more interest from the scientific society as a replacement to antibiotics. However, silver compounds may be too soluble and even toxic for the host. Encapsulation might be very advantageous in order to increase the stability and biocompatibility of silver drugs. In addition, it allows a more controllable release of antimicrobial agents. In this study, ceria nanocapsules with integrated silver nanoparticles (Ag/CeO2 NCs) were synthesized according to the method depicted in the figure below. The capsules were then characterized using XRD, TEM, SEM, and FT-IR. Silver nanoparticles (Ag NPs) are visible on the surface as well as in the cavity of Ag/CeO2 NCs, suggesting that they were integrated within the ceria shell. This system can release silver during a period exceeding 3 months, which demonstrates a good release control of the antimicrobial agent. The Ag/CeO2 NCs have a low cytotoxicity towards human alveolar epithelial cells, but allow only a poor cell attachment. In order to improve the cell attachment on the nanocapsules, as well as to reduce the silver being released, a TiO2 coating around the Ag/CeO2 NCs was added to this system. This resulted in the so-called Ag/CeO2/TiO2 NCs. These novel nanocontainers were also characterized in order to evaluate the cytotoxicity and antimicrobial activity.

scholarly journals Impact of chemical composition of ecotoxicological test media on the stability and aggregation status of silver nanoparticles

2016 ◽  
Vol 3 (2) ◽  
pp. 418-433 ◽  
Author(s):  
George Metreveli ◽  
Bianca Frombold ◽  
Frank Seitz ◽  
Alexandra Grün ◽  
Allan Philippe ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Chemical Composition ◽  
Ag Nps ◽  
Ecotoxicological Test ◽  
The Stability

Aggregation status of Ag NPs in ecotoxicological test media is controlled by the Ca2+/Mg2+ ratio, presence of Cl− and Br− and NOM quality.

Effect of cigarette smoke and its condensates on alveolar epithelial cell injury in vitro

1994 ◽  
Vol 266 (1) ◽  
pp. L92-L100 ◽  
Author(s):  
S. Lannan ◽  
K. Donaldson ◽  
D. Brown ◽  
W. MacNee
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Cigarette Smoke ◽  
Cell Injury ◽  
Cell Attachment ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelial Cells ◽  
Type Ii ◽  
Alveolar Epithelial

The oxidant-antioxidant balance in the airspaces of the lungs may be critical in protecting the lungs from the effects of cigarette smoke. We studied the effect of cigarette smoke and its condensates on the detachment, attachment, and proliferation of the A549 human alveolar epithelial cell line, in an in vitro model of cell injury and regeneration and the protective effects of antioxidants. Whole and vapor phase cigarette smoke decreased 51Cr-labeled A549 cell attachment, increased cell detachment, and decreased cell proliferation, as assessed by [3H]thymidine uptake. Freshly isolated rat type II alveolar epithelial cells showed an enhanced susceptibility to smoke-induced cell lysis when compared with the A549 cell line. Reduced glutathione (GSH) (400 microM) protected against the effects of cigarette smoke exposure on cell attachment, proliferation, and detachment. Depletion of intracellular GSH with buthionine sulfoxamine enhanced the epithelial cell detachment injury produced by smoke condensates. We conclude that cigarette smoke and its condensates cause an oxidant-induced injury to A549 human type II alveolar epithelial cells. Both intra- and extracellular GSH have important roles in protecting epithelial cells from the injurious effects of cigarette smoke.

scholarly journals Bactericidal and In-Vitro Cytotoxic Efficacy of Silver Nanoparticles (Ag-NPs) Fabricated by Endophytic Actinomycetes and Their Use as Coating for the Textile Fabrics

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2082 ◽  
Author(s):  
Salem S. Salem ◽  
Ehab F. EL-Belely ◽  
Gniewko Niedbała ◽  
Maryam M. Alnoman ◽  
Saad El-Din Hassan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Inhibition Zone ◽  
In Vitro Cytotoxicity ◽  
Ag Nps ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
The Stability

An endophytic strain of Streptomyces antimycoticus L-1 was isolated from healthy medicinal plant leaves of Mentha longifolia L. and used for the green synthesis of silver nanoparticles (Ag-NPs), through the use of secreted enzymes and proteins. UV–vis spectroscopy, Fourier-transform infrared (FT-IR), transmission electron microscopy (TEM), X-ray diffraction (XRD), and dynamic light scattering (DLS) analyses of the Ag-NPs were carried out. The XRD, TEM, and FT-IR analysis results demonstrated the successful biosynthesis of crystalline, spherical Ag-NPs with a particle size of 13–40 nm. Further, the stability of the Ag-NPs was assessed by detecting the surface Plasmon resonance (SPR) at 415 nm for one month or by measuring the NPs surface charge (−19.2 mV) by zeta potential analysis (ζ). The green-synthesized Ag-NPs exhibited broad-spectrum antibacterial activity at different concentrations (6.25–100 ppm) against the pathogens Staphylococcus aureus, Bacillus subtilis Pseudomonas aeruginosa, Escherichia coli, and Salmonella typhimurium with a clear inhibition zone ranging from (9.5 ± 0.4) nm to (21.7 ± 1.0) mm. Furthermore, the green-synthesized Ag-NPs displayed high efficacy against the Caco-2 cancerous cell line (the half maximal inhibitory concentration (IC50) = 5.7 ± 0.2 ppm). With respect to antibacterial and in-vitro cytotoxicity analyses, the Ag-NPs concentration of 100 ppm was selected as a safe dose for loading onto cotton fabrics. The scanning electron microscopy connected with energy-dispersive X-ray spectroscopy (SEM-EDX) for the nano-finished fabrics showed the distribution of Ag-NPs as 2% of the total fabric elements. Moreover, the nano-finished fabrics exhibited more activity against pathogenic Gram-positive and Gram-negative bacteria, even after 10 washing cycles, indicating the stability of the treated fabrics.

scholarly journals Silver Nanoparticles Induce a Triclosan-Like Antibacterial Action Mechanism in Multi-Drug Resistant Klebsiella pneumoniae

2021 ◽  
Vol 12 ◽  
Author(s):  
Vikram Pareek ◽  
Stéphanie Devineau ◽  
Sathesh K. Sivasankaran ◽  
Arpit Bhargava ◽  
Jitendra Panwar ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Silver Nanoparticles ◽  
Klebsiella Pneumoniae ◽  
Antimicrobial Agents ◽  
Transcriptional Analysis ◽  
Antibacterial Action ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Action Mechanism ◽  
Ag Nps

Infections associated with antimicrobial-resistant bacteria now represent a significant threat to human health using conventional therapy, necessitating the development of alternate and more effective antibacterial compounds. Silver nanoparticles (Ag NPs) have been proposed as potential antimicrobial agents to combat infections. A complete understanding of their antimicrobial activity is required before these molecules can be used in therapy. Lysozyme coated Ag NPs were synthesized and characterized by TEM-EDS, XRD, UV-vis, FTIR spectroscopy, zeta potential, and oxidative potential assay. Biochemical assays and deep level transcriptional analysis using RNA sequencing were used to decipher how Ag NPs exert their antibacterial action against multi-drug resistant Klebsiella pneumoniae MGH78578. RNAseq data revealed that Ag NPs induced a triclosan-like bactericidal mechanism responsible for the inhibition of the type II fatty acid biosynthesis. Additionally, released Ag+ generated oxidative stress both extra- and intracellularly in K. pneumoniae. The data showed that triclosan-like activity and oxidative stress cumulatively underpinned the antibacterial activity of Ag NPs. This result was confirmed by the analysis of the bactericidal effect of Ag NPs against the isogenic K. pneumoniae MGH78578 ΔsoxS mutant, which exhibits a compromised oxidative stress response compared to the wild type. Silver nanoparticles induce a triclosan-like antibacterial action mechanism in multi-drug resistant K. pneumoniae. This study extends our understanding of anti-Klebsiella mechanisms associated with exposure to Ag NPs. This allowed us to model how bacteria might develop resistance against silver nanoparticles, should the latter be used in therapy.

scholarly journals Optimization of antimicrobial efficiency of silver nanoparticles against three oral microorganisms in irreversible hydrocolloid impressions

2021 ◽  
Author(s):  
Ahmad Jafari ◽  
Ramin Mazaheri Nezhad Fard ◽  
Sima Shahabi ◽  
Farid Abbasi ◽  
Golshid Javdani Shahedin ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Antimicrobial Agents ◽  
Diffusion Method ◽  
Ag Nps ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Irreversible Hydrocolloid ◽  
Predicted Model ◽  
Water Ratio

Background and Objectives: Silver nanoparticles (Ag-NPs) are potent antimicrobial agents, which have recently been used in dentistry. The aim of the current study was to optimize antimicrobial activity of Ag-NPs used in preparing irre- versible hydrocolloid impressions against three microorganisms of Escherichia coli, Streptococcus mutans and Candida albicans. Materials and Methods: After assessing antimicrobial activity of the compound using disk diffusion method, three parame- ters of concentration of Ag-NPs (250-1000 ppm), ratio of hydrocolloid impression material powder to water (0.30-0.50) and time of mixing (20.0-60.0 s), affecting antimicrobial activity of irreversible hydrocolloid impression materials against the three microorganisms, were optimized. This combined process was successfully modeled and optimized using Box-Behnken design with response surface methodology (RSM). Decreases in colony number of E. coli, S. mutans and C. albicans were proposed as responses. Results: Qualitative antimicrobial assessments respectively showed average zone of inhibition (ZOI) of 3.7 mm for E. coli, 3.5 mm for S. mutans and 4 mm for C. albicans. For all responses, when the mixing duration and powder-to-water ratio increased, the circumstances (mixing duration of 59.38 s, powder-to-water ratio of 0.4 and Ag-NP concentration of 992 response) increased. Results showed that in optimum ppm, the proportion of decreases in colony numbers was maximum (89.03% for E. coli, 87.08% for S. mutans and 74.54% for C. albicans). Regression analysis illustrated a good fit of the ex- perimental data to the predicted model as high correlation coefficients validated that the predicted model was well fitted with data. Values of R2Adj with R2Pred were associated to the accuracy of this model in all responses. Conclusion: Disinfection efficiency dramatically increased with increasing of Ag-NP concentration, powder-to-water ratio and mixing time.

scholarly journals Extracellular probiotic lipase capped silver nanoparticles as highly efficient broad spectrum antimicrobial agents

RSC Advances ◽  
2018 ◽  
Vol 8 (55) ◽  
pp. 31358-31365 ◽  
Author(s):  
Imran Khan ◽  
Nivetha Sivasankaran ◽  
Ravikiran Nagarjuna ◽  
Ramakrishnan Ganesan ◽  
Jayati Ray Dutta
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Broad Spectrum ◽  
Antimicrobial Agents ◽  
Ag Nps ◽  
Highly Efficient

A series of Ag NPs capped with different concentrations of probiotic lipase have been synthesized. The obtained Ag NPs exhibited efficient broad spectrum antimicrobial activity at concentrations much lower than the LC50values of zebrafish.

Effect of radiation on lecithin metabolism, surface activity, and compliance of rat lung

1970 ◽  
Vol 48 (10) ◽  
pp. 685-694 ◽  
Author(s):  
A. Naimark ◽  
D. Newman ◽  
D. H. Bowden
Keyword(s):  
Surface Activity ◽  
Endothelial Damage ◽  
Alveolar Epithelial Cells ◽  
Phospholipid Content ◽  
Alveolar Epithelial ◽  
The Stability ◽  
The Right ◽  
Cut Surface ◽  
Qualitative Changes

The effect of ionizing radiation on lecithin metabolism, surface activity, and compliance of the lung was studied in rats. At intervals of 1 to 4 months after irradiation of the right hemithorax (3000 R, single dose) exposed lungs were compared with contralateral shielded lungs and with the right lungs of nonirradiated control rats. Four months after exposure, irradiated lungs did not differ in DNA content from controls but exhibited decreased lecithin content, depressed incorporation of palmitate-1-14C into lecithin in vitro, and a decrease in the percentage of palmitic acid in the lecithin fraction. Changes in other phospholipids were qualitatively similar. The stability of bubbles expressed from the cut surface of irradiated lungs decreased progressively with time, indicating impaired surface activity of the lung-lining layer. This was associated with a progressive decrease in compliance of the lung. Electron microscopy revealed no qualitative changes in the alveolar epithelial cells. Morphologic evidence of injury was most prominent in the capillaries and could be detected before changes in phospholipid content, surface activity, and compliance. Our studies indicate that irradiation of the lung is associated with alterations in lecithin content, in surface activity, and in compliance of the lung, and suggest that such changes are secondary to endothelial damage rather than a reflection of a primary effect on surface activity.

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