Synthesis of Fe3O4 Core-Shell Nanoparticles; Embedding Cu, Ag, Au Metals in the Surfaces that Were Modified by PPG and PEG Polymers and Investigation of Antibacterial Properties of These Composites

Kiani Karanji, Ahmad | 2012

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 43844 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Gholami, Mohammad Reza; Haghighi, Saeed
  7. Abstract:
  8. In this project, Fe3O4 magnetic nanoparticles were prepared by co-precipitation method. For protecting them against oxidation and also avoiding from direct contact between core and additional materials that probably makes unwanted reactions, the surface of nanoparticles were coated by SiO2 layer. Being easy to modify and having the control of interactions between nanoparticles are the advantages of coating nanoparticles with silica. The obtained Fe3O4@SiO2 core-shell nanoparticles were covered by two types of polymer (PPG and PEG). The basis of the composite was characterized by VSM, TGA, SEM, XRD, and FT-IR analytical methods.
    The antibacterial activities of Copper, Silver and Gold which had been embedded in the branches of polymers were studied. In addition, the antibacterial activity of Silver compared with Gold and Copper according to the role of the polymers which embedded the metallic particles into their branches. The results determined that the basis of the composite didn’t have any activity against bacteria, as the result the whole of the observed antibacterial activity refers to metal nanoparticles. According to the tests for antibacterial activity, it was observed that Copper and Silver can be trapped in both PEG and PPG branches, while PPG layer showed a better role and activity for these metals nanoparticles. In addition, Gold only can penetrate in PEG polymeric branches.
    Investigation of reuse ability, Minimum Bacterial Concentration (MBC) and Minimal Inhibitory Concentration (MIC) for selected composites were studied. By considering TEM pictures the bacteria was observed without uniform and continues cell-wall that it previously had. In addition, a great amount of large granules were observable on the surface of the bacteria. Metals can prevent bacteria to transfer its vital material into the cell and also prevent it to drive out its waists by making reaction with the proteinic pores on the cell-wall. Penetrating into the cytoplasmic liquid and interaction with DNA, metals can have another mechanism to destroying bacteria and make it dead
  9. Keywords:
  10. Magnetic Nanodot ; Antibacterial Activity ; Staphylococcus Aureus ; Polyethylen Glycol (PEG) ; Escherichia Coli Bacteria ; Polypropylene Glycol (PPG)

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