Mestrado em Bioquímica

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http://repositorio.ufes.br/handle/10/17562

Nível: Mestrado Acadêmico
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Navegando Mestrado em Bioquímica por Assunto "Antioxidantes"

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    Avaliação físico-química de nanopartículas de ouro reduzidas com citrato de sódio e capeadas com Virola oleifera
    (Universidade Federal do Espírito Santo, 2017-06-30) Corrêa, Andressa dos Santos; Oliveira, Jairo Pinto de; Guimarães, Marco Cesar Cunegundes; Nogueira, Breno Valentim; Silva, André Romero da
    The capping of gold nanocrystals using sodium citrate with Virola oleifera was the focus of this thesis, which aim/aiming at synthesize and characterize evaluate the final extract concentration and pH influence in surface particle adsorption. Furthermore, was analysed antioxidant activity and citotoxicity of AuNPs, for investigate your potential biological application. For this goal, the best capping time, and subsequently the optimum pH range and final extract concentration was determined and was realizes a 32 factorial design with 3 levels and 2 variables (pH and extract concentration) to verify the optimal capping conditions. In this way, it has been proved the adsorption was most intense between pH 3 and 5 and the most stable was the lower final extract concentration. The x-ray diffraction and the transmission electron microscopy confirmed the face-centered cubic structure of citrate AuNPs and the quasi spherical aspect, respectively. The adsorption of aromatic molecules was confirmed by spectroscopy techniques: Fourier-Transform Infrared (FTIR) and Raman. The DPPH and FRAP analyzes shows enhancement of antioxidant activity with capping of citrate gold nanoparticles. Furthermore, the citotoxicity assay shows low citotoxicity of capped gold nanoparticles.
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    Proposição de uma rota de síntese verde de nanopartículas de ouro reduzidas com resina de Virola oleifera através do planejamento fatorial
    (Universidade Federal do Espírito Santo, 2018-02-15) Contreras Alvarez, Luis Alberto; Oliveira, Jairo Pinto de; Guimarães, Marco Cesar Cunegundes; Silva, André Romero da; Ribeiro, Josimar
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    Síntese e caracterização de nanopartículas de ouro com resina de Virola oleifera e avaliação do seu efeito antibacteriano
    (Universidade Federal do Espírito Santo, 2015-09-02) Milaneze, Bárbara Altoé; Guimarães, Marco Cesar Cunegundes; Olivares, Fabio Lopes; Nogueira, Breno Valentim
    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 18 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.