Caracterização físico-química e ação antimicrobiana de nanopartículas de prata obtidas por uma nova síntese

• Ano de defesa: 2010
• Autor(a) principal: Araújo, Emiliane Andrade
• Orientador(a): Andrade, Nélio José de
• Banca de defesa: Pires, Ana Clarissa dos Santos , Martins, Maurilio Lopes
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Ciência e Tecnologia de Alimentos
• Departamento: Ciência de Alimentos; Tecnologia de Alimentos; Engenharia de Alimentos
• País: BR
• Palavras-chave em Português: Polissulfona; Acetato de celulose; Modificações de membranas; Biofouling; Àgua
• Palavras-chave em Inglês: Polysulfone; Cellulose acetate; Modifications membrane; Biofouling; Water
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS
• Link de acesso: http://locus.ufv.br/handle/123456789/451

The synthesis of silver nanoparticles has attracted interest due to new and different physical and chemical characteristics they possess and these attractive features enable applications in various fields. The present study aimed to: I) characterize the silver nanoparticles obtained by Fernandes (2010) method, using techniques of infrared spectroscopy, dynamic light scattering, transmission electron microscopy, X-ray diffraction and atomic emission to quantify the nanoparticles synthesized II) evaluate the antimicrobial effect of silver nanoparticles obtained by different methodologies on Staphylococcus aureus, Listeria innocua, Salmonella Choleraesuis, Pseudomonas aeruginosa, Escherichia coli and Bacillus cereus bacteria as well as evaluating the ability of these nanoparticles to remove vegetative cells adhered on stainless steel surfaces; III) evaluate the capacity of silver nanoparticles to modify the thermodynamic characteristics of stainless steel surface to reduce the process of adhesion and biofilm formation. Measures of transmission electron microscopy, infrared, x-ray diffraction and dynamic light scattering confirmed the presence of silver nanoparticles synthesized in the dispersion and they had an average diameter ranging from 2.8 to 4.4 nm. It was observed that this process of formation of nanoparticles is characterized in an auto redox reaction of silver sulfadiazine catalysed by micelles of the dodecyltrimethylammonium bromide. The analysis of atomic emission confirmed the micelar catalyse, once with increasing number of micelles of there was an increase in the concentration of nanoparticles in dispersion. The silver nanoparticles evaluated showed good antimicrobial activity for Gram-positive and Gram-negative bacteria tested. Concentrated nanoparticles were efficient in removing adhered cells of Pseudomonas aeruginosa on stainless steel coupons (10 mm x 10 mm) reaching five decimal reductions after contact with the antimicrobial agent by immersion for 30 minutes. Concentrated nanoparticles (60 mg/L) were also efficient in removing adhered cells of Bacillus cereus on stainless steel cylinders (336,5 cm2). Finally, the thermodynamics of adhesion became unfavorable after the stainless steel surface was conditioned with silver nanoparticles to the bacteria tested here. Therefore, the silver nanoparticles obtained by this new and simple methodology have to be an interesting strategy in the food industry to control the adhesion and subsequent biofilm formation.