Name: Bárbara Altoé Milaneze
Type: MSc dissertation
Publication date: 02/09/2015

Namesort ascending Role
Marco Cesar Cunegundes Guimarães Advisor *

Examining board:

Namesort ascending Role
Marco Cesar Cunegundes Guimarães Advisor *
Fabio Lopes Olivares External Examiner *
Breno Valentim Nogueira Internal Examiner *

Summary: Introduction: The use of nanotechnology is changing the way different types of materials are used. Colloidal synthesis is an extremely versatile method, relatively low cost compared to other methods of production of metal nanoparticles (NP's). Their behavior is related to the environment in which it finds itself, stability, chemical composition, degree of aggregation, morphology and size, so modulations at the time of synthesis are crucial for biological activity. Much of the route traditionally used for the production of metal nanoparticles, start from toxic solvents that end up giving rise to harmful wastes to health and the environment. NP's studies have shown that they have great potential as antimicrobial agents, drug delivery, among others. This study aimed to develop a sustainable methodology for the synthesis of gold nanoparticles using as reducing agent Virola resin solution oleifera, and further evaluation of antimicrobial and antioxidant activity. Methods: The gold nanoparticles (AUNP's) were synthesized by oxidation-reduction, based on a factorial design 3² WHERE variables were time and concentration of reducing agent. The characterization was performed with UV-Vis analysis, microscopy, Zeta potential, ICP-MS and IR. The antioxidant potential was evaluated for both the resin and for the AUNP's. The antibacterial activity was tested against Staphylococcus aureus and Escherichia coli DH5α 1117 by microdilution technique in broth, and rapid interaction by shaking, followed by transmission electron microscopy analyzes. Results: The resin ferrule oleifera was able to reduce as efficiently as gold sodium citrate (reducing agent used traditionally). Among the varying only the concentration of the reducing agent it was important to determine the characteristics of nanoparticles. The peak absorbance between 520 and 540nm occurred. Together with such the microscopy imaging data confirm the presence of gold nanoparticles. From Green synthesis had the AUNP's various forms and zeta potential showed that AUNP's were stable. The ICP-MS analysis showed that the concentration and reduced with green gold synthesis was higher than with citrate. The gold nanoparticles had antioxidant potential and were able to inhibit the growth of S. aureus by interaction with the membrane. Conclusions: Ferrule oleifera resin showed an excellent alternative to AUNP's synthesis, yielding particles with antioxidant activity, and effective in the inhibition of S. aureus.

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