oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Effect of Silver-Loaded Zeolite on the Susceptibility of Escherichia Coli Against Antibiotics  [PDF]
Yoshihiro Inoue, Hajime Hamashima
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2012, DOI: 10.4236/jbnb.2012.31015
Abstract: We investigated the effect of silver-loaded zeolite (Ag-Z) on antibacterial activity of some antibiotics against Es-cherichia coli against antibiotics. We treated the bacterial suspension of E. coli by Ag-Z to be the level which the decrease of viable cell count was not observed. Susceptibility test of E. coli treated with Ag-Z was carried out against four antibiotics with different mode of action. Apparent increase in susceptibility was found in the case of rifampicin, not in others. The result suggests that application of Ag-Z to ward environment might give a good outcome at the treatment with rifampicin and at the treatment for pathogenic microbe spread through the air, such as tubercle bacilli.
Electrochemical Analysis of the Redox State of Silver Contained in Antibacterial Material  [PDF]
Yoshihiro Inoue, Hajime Hamashima
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2012, DOI: 10.4236/jbnb.2012.32019
Abstract: Introduction of silver into some inorganic material causes the resulting mixture to have antibacterial activity. Here, we investigated the role of silver in the bactericidal activity of silver-loaded zeolite, by measuring the effects of silver-loaded zeolite on Escherichia coli cell viability under conditions in which the oxidation state of the silver was controlled electrochemically. Bactericidal activity was observed when the sweeping voltage between 0 and 0.7 V was applied to the silver electrode. When nitrogen gas bubbling or reactive oxygen scavengers were added to the experimental system, bactericidal activity decreased. These results indicated that the redox cycle, Ag0 <—> Ag+, caused the dissolved oxygen to form reactive oxygen species.
Preparation and Antibacterial Performance of Zeolite Loaded Silver Antibacterial Agent
载银4A沸石抗菌剂的制备及其抗菌性能的研究

HOU Wen-Sheng,WEI Li-Qiao,DAI Jin-ming,JIA Hu-Sheng,XU Bing-she,
侯文生
,魏丽乔,戴晋明,贾虎生,许并社

无机材料学报 , 2005,
Abstract: The silver-supporting antibacterial zeolite was prepared by the ion exchanging method with zeolite as the carrier and AgNO3 solution as the exchanging solution. The influence of preparation process on exchanging ability of zeolite was studied and the optimum preparation process was determined. The structure was characterized by X-ray diffraction (XRD) and the antibacterial ability was tested. The results show that the exchanging ability is greatly influenced by the concentration of exchanging solution, temperature, time and pH values. The suitable concentration of exchanging solution is 0.1mol/L. The pH value should be controlled between 6~8. In view of energy consumption, ambient temperature is appropriate, but in view of reaction time, the reaction should be heated. The silver-supporting antibacterial zeolite has an excellent antibacterial performance against E.coli and S.faecalis.
Fabrication of silver nanoparticles doped in the zeolite framework and antibacterial activity  [cached]
Kamyar Shameli,Mansor Bin Ahmad,Mohsen Zargar,et al
International Journal of Nanomedicine , 2011,
Abstract: Kamyar Shameli1, Mansor Bin Ahmad1, Mohsen Zargar2, Wan Md Zin Wan Yunus1, Nor Azowa Ibrahim11Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Selangor, Malaysia; 2Department of Biology, Islamic Azad University, Qum IranAbstract: Using the chemical reduction method, silver nanoparticles (Ag NPs) were effectively synthesized into the zeolite framework in the absence of any heat treatment. Zeolite, silver nitrate, and sodium borohydride were used as an inorganic solid support, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite lattice by an ion-exchange path. After the reduction process, Ag NPs formed in the zeolite framework, with a mean diameter of about 2.12–3.11 nm. The most favorable experimental condition for the synthesis of Ag/zeolite nanocomposites (NCs) is described in terms of the initial concentration of AgNO3. The Ag/zeolite NCs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, and Fourier transform infrared. The results show that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antibacterial activity of Ag NPs in zeolites was investigated against Gram-negative bacteria (ie, Escherichia coli and Shigella dysentriae) and Gram-positive bacteria (ie, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus) by disk diffusion method using Mueller–Hinton agar at different sizes of Ag NPs. All of the synthesized Ag/zeolite NCs were found to have antibacterial activity. These results show that Ag NPs in the zeolite framework can be useful in different biological research and biomedical applications.Keywords: silver nanoparticles, zeolite, antibacterial activity, Mueller–Hinton agar, transmission electron microscopy
Fabrication of silver nanoparticles doped in the zeolite framework and antibacterial activity
Kamyar Shameli, Mansor Bin Ahmad, Mohsen Zargar, et al
International Journal of Nanomedicine , 2011, DOI: http://dx.doi.org/10.2147/IJN.S16964
Abstract: brication of silver nanoparticles doped in the zeolite framework and antibacterial activity Original Research (8261) Total Article Views Authors: Kamyar Shameli, Mansor Bin Ahmad, Mohsen Zargar, et al Published Date February 2011 Volume 2011:6 Pages 331 - 341 DOI: http://dx.doi.org/10.2147/IJN.S16964 Kamyar Shameli1, Mansor Bin Ahmad1, Mohsen Zargar2, Wan Md Zin Wan Yunus1, Nor Azowa Ibrahim1 1Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Selangor, Malaysia; 2Department of Biology, Islamic Azad University, Qum Iran Abstract: Using the chemical reduction method, silver nanoparticles (Ag NPs) were effectively synthesized into the zeolite framework in the absence of any heat treatment. Zeolite, silver nitrate, and sodium borohydride were used as an inorganic solid support, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite lattice by an ion-exchange path. After the reduction process, Ag NPs formed in the zeolite framework, with a mean diameter of about 2.12–3.11 nm. The most favorable experimental condition for the synthesis of Ag/zeolite nanocomposites (NCs) is described in terms of the initial concentration of AgNO3. The Ag/zeolite NCs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, and Fourier transform infrared. The results show that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antibacterial activity of Ag NPs in zeolites was investigated against Gram-negative bacteria (ie, Escherichia coli and Shigella dysentriae) and Gram-positive bacteria (ie, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus) by disk diffusion method using Mueller–Hinton agar at different sizes of Ag NPs. All of the synthesized Ag/zeolite NCs were found to have antibacterial activity. These results show that Ag NPs in the zeolite framework can be useful in different biological research and biomedical applications.
Antimicrobial, Mechanical and Thermal Studies of Silver Particle-Loaded Polyurethane  [PDF]
Deepen Paul,Sharmistha Paul,Nima Roohpour,Mark Wilks,Pankaj Vadgama
Journal of Functional Biomaterials , 2013, DOI: 10.3390/jfb4040358
Abstract: Silver-particle-incorporated polyurethane films were evaluated for antimicrobial activity towards two different bacteria: Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus). Distributed silver particles sourced from silver nitrate, silver lactate and preformed silver nanoparticles were mixed with polyurethane (PU) and variously characterized by field emission scanning electron microscopy (FESEM), fourier transform infra-red (FTIR) spectroscopy, X-ray diffraction (XRD) and contact angle measurement. Antibacterial activity against E.coli was confirmed for films loaded with 10% (w/w) AgNO 3, 1% and 10% (w/w) Ag lactate and preformed Ag nanoparticles. All were active against S. aureus, but Ag nanoparticles loaded with PU had a minor effect. The apparent antibacterial performance of Ag lactate-loaded PU is better than other Ag ion-loaded films, revealed from the zone of inhibition study. The better performance of silver lactate-loaded PU was the likely result of a porous PU structure. FESEM and FTIR indicated direct interaction of silver with the PU backbone, and XRD patterns confirmed that face-centred cubic-type silver, representative of Ag metal, was present. Young’s modulus, tensile strength and the hardness of silver containing PU films were not adversely affected and possibly marginally increased with silver incorporation. Dynamic mechanical analysis (DMA) indicated greater thermal stability.
CHEMICALLY FABRICATED SILVER NANOPARTICLES ENHANCES THE ACTIVITY OF ANTIBIOTICS AGAINST SELECTED HUMAN BACTERIAL PATHOGENS  [PDF]
S. Thangapandiyan and P. Prema*
International Journal of Pharmaceutical Sciences and Research , 2012,
Abstract: Due to the outbreak of infectious diseases caused by different pathogenic bacteria and the development of antibiotic resistance, the pharmaceutical companies and the researchers are now searching for new unconventional antibacterial agents. Nanotechnology represents a modern and innovative approach to develop new formulations based on metallic nanoparticles with antimicrobial properties. The potential bioactivity of chemically fabricated silver nanoparticles has been extensively studied. However, the antibacterial activity of silver nanoparticles individually or in combination with different antibiotics has not been demonstrated. In the present investigations, the effect of silver nanoparticles on the antibacterial activity of different antibiotics was evaluated against selected human bacterial pathogens such as Staphylococcus aureus, Streptococcus epidermis, Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus by disc diffusion method. In the presence of sub - inhibitory concentration of silver nanoparticles (100μL/disc), the antibacterial activities of all antibiotics are increased from 1 mm to 10 mm. The maximum fold increase was noticed for vancomycin against Pseudomonas aeruginosa (66.67%), Escherichia coli (62.50%), and Staphylococcus aureus (46%) followed by rifampicin against Bacillus cereus (66.67%) and kanamycin against Streptococcus epidermis (25%). These results signify that the silver nanoparticles showed potential antibacterial action of -lactams, glycopeptides, aminoglycosides, sulphonamides suggesting a possible utilization of silver nanocompounds in combination therapy against selected pathogens used in the experiment.
Silver nanoparticles embedded in zeolite membranes: release of silver ions and mechanism of antibacterial action  [cached]
Nagy A,Harrison A,Sabbani S,Munson,Jr. RS
International Journal of Nanomedicine , 2011,
Abstract: Amber Nagy1, Alistair Harrison2, Supriya Sabbani3, Robert S Munson, Jr2, Prabir K Dutta3, W James Waldman11Department of Pathology, The Ohio State University; 2Center for Microbial Pathogenesis, Research Institute at Nationwide Children's Hospital, 3Department of Chemistry, The Ohio State University, Columbus, OH, USABackground: The focus of this study is on the antibacterial properties of silver nanoparticles embedded within a zeolite membrane (AgNP-ZM).Methods and Results: These membranes were effective in killing Escherichia coli and were bacteriostatic against methicillin-resistant Staphylococcus aureus. E. coli suspended in Luria Bertani (LB) broth and isolated from physical contact with the membrane were also killed. Elemental analysis indicated slow release of Ag+ from the AgNP-ZM into the LB broth. The E. coli killing efficiency of AgNP-ZM was found to decrease with repeated use, and this was correlated with decreased release of silver ions with each use of the support. Gene expression microarrays revealed upregulation of several antioxidant genes as well as genes coding for metal transport, metal reduction, and ATPase pumps in response to silver ions released from AgNP-ZM. Gene expression of iron transporters was reduced, and increased expression of ferrochelatase was observed. In addition, upregulation of multiple antibiotic resistance genes was demonstrated. The expression levels of multicopper oxidase, glutaredoxin, and thioredoxin decreased with each support use, reflecting the lower amounts of Ag+ released from the membrane. The antibacterial mechanism of AgNP-ZM is proposed to be related to the exhaustion of antioxidant capacity.Conclusion: These results indicate that AgNP-ZM provide a novel matrix for gradual release of Ag+.Keywords: silver nanoparticles, zeolite, antibacterial agent, oxidative stress
Metal loaded zeolite adsorbents for hydrogen cyanide removal
Ping Ning,Juan Qiu,Xueqian Wang,Wei Liu,Wei Chen,
Ping Ning
,Juan Qiu,Xueqian Wang,Wei Liu,Wei Chen

环境科学学报(英文版) , 2013,
Abstract: Metal (Cu, Co, or Zn) loaded ZSM-5 and Y zeolite adsorbents were prepared for the adsorption of hydrogen cyanide (HCN) toxic gas. The results showed that the HCN breakthrough capacity was enhanced significantly when zeolites were loaded with Cu. The physical and chemical properties of the adsorbents that influence the HCN adsorption capacity were analyzed. The maximal HCN breakthrough capacities were about the same for both zeolites at 2.2 mol of HCN/mol of Cu. The Cu2p XPS spectra showed that the possible species present were Cu2O and CuO. The N1s XPS data and FT-IR spectra indicated that CN- would be formed in the presence of Cu+/Cu2+ and oxygen gas, and the reaction product could be adsorbed onto Cu/ZSM-5 zeolite more easily than HCN.
Silver nanoparticles embedded in zeolite membranes: release of silver ions and mechanism of antibacterial action
Nagy A, Harrison A, Sabbani S, Munson,Jr. RS, Dutta PK, Waldman WJ
International Journal of Nanomedicine , 2011, DOI: http://dx.doi.org/10.2147/IJN.S24019
Abstract: nanoparticles embedded in zeolite membranes: release of silver ions and mechanism of antibacterial action Original Research (4872) Total Article Views Authors: Nagy A, Harrison A, Sabbani S, Munson,Jr. RS, Dutta PK, Waldman WJ Published Date September 2011 Volume 2011:6 Pages 1833 - 1852 DOI: http://dx.doi.org/10.2147/IJN.S24019 Amber Nagy1, Alistair Harrison2, Supriya Sabbani3, Robert S Munson, Jr2, Prabir K Dutta3, W James Waldman1 1Department of Pathology, The Ohio State University; 2Center for Microbial Pathogenesis, Research Institute at Nationwide Children's Hospital, 3Department of Chemistry, The Ohio State University, Columbus, OH, USA Background: The focus of this study is on the antibacterial properties of silver nanoparticles embedded within a zeolite membrane (AgNP-ZM). Methods and Results: These membranes were effective in killing Escherichia coli and were bacteriostatic against methicillin-resistant Staphylococcus aureus. E. coli suspended in Luria Bertani (LB) broth and isolated from physical contact with the membrane were also killed. Elemental analysis indicated slow release of Ag+ from the AgNP-ZM into the LB broth. The E. coli killing efficiency of AgNP-ZM was found to decrease with repeated use, and this was correlated with decreased release of silver ions with each use of the support. Gene expression microarrays revealed upregulation of several antioxidant genes as well as genes coding for metal transport, metal reduction, and ATPase pumps in response to silver ions released from AgNP-ZM. Gene expression of iron transporters was reduced, and increased expression of ferrochelatase was observed. In addition, upregulation of multiple antibiotic resistance genes was demonstrated. The expression levels of multicopper oxidase, glutaredoxin, and thioredoxin decreased with each support use, reflecting the lower amounts of Ag+ released from the membrane. The antibacterial mechanism of AgNP-ZM is proposed to be related to the exhaustion of antioxidant capacity. Conclusion: These results indicate that AgNP-ZM provide a novel matrix for gradual release of Ag+.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.