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    Synthesis and Characterisation of Silver(I)-Bioglues and Assessment of Biological Activity of AgNO3 Against Staphylococcus aureus


    Smith, Alanna (2012) Synthesis and Characterisation of Silver(I)-Bioglues and Assessment of Biological Activity of AgNO3 Against Staphylococcus aureus. PhD thesis, National University of Ireland Maynooth.

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    Abstract

    Bioglue samples prepared in the absence and in the presence of Ag(I) ions (using AgNO3 and [Ag2(3,6,9-tdda)].2H2O (tddaH2 = trioxaundecanedioic acid)) were thermally stable and had the ability to swell in the presence of water. Generally, for the Ag(I)-Bioglues, as the amount of added Ag(I) ions decreased the degree of swelling increased. The surface morphology of the Bioglue without Ag(I) ions was very porous in comparison to the smooth surface of the Ag(I)-Bioglues. In tests using wood and pig skin, the adhesive properties of the Bioglues decreased with increasing amounts of added Ag(I) ions. The elasticity of the Bioglue also reduced upon incorporation of Ag(I) ions. Leaching of bioactive Ag(I) ions from AgNO3-Bioglue samples increased over time and equilibrium was reached after 55 h. Ag(I)-Bioglues were reduced to Ag(0) using sodium borohydride and sodium citrate, but there was no evidence of Ag(0) nanoparticle formation. Bioglue formulated without Ag(I) ions is readily colonized by microbes. The Ag(I)-Bioglues inhibit the growth of the fungal pathogen, Candida albicans, and are even more potent against the bacterial species, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus. S. aureus cells exposed to AgNO3 show a short-term increase in the activity of antioxidant enzymes, such as superoxide dismutase, catalase and, to a lesser extent, glutathione reductase, but this activity decreases as the cells lose viability. AgNO3 also induces an increase in the amount of amino acid leakage from S. aureus cells, suggesting that Ag(I) ions affect membrane permeability. Proteomic analysis revealed that S. aureus cells were experiencing stress as a result of exposure to AgNO3, which causes an increase in the expression of virulent and essential metabolic proteins. These Ag(I)-Bioglues have the potential to offer significant antimicrobial protection if used in surgical wound closure.

    Item Type: Thesis (PhD)
    Keywords: Silver(I)-Bioglues; Biological Activity; AgNO3; Staphylococcus aureus;
    Academic Unit: Faculty of Science and Engineering > Biology
    Faculty of Science and Engineering > Chemistry
    Item ID: 4765
    Depositing User: IR eTheses
    Date Deposited: 05 Feb 2014 16:21
    URI:

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