Síntese, caracterização e ação antimicrobiana de nanopartículas de prata

Detalhes bibliográficos
Autor(a) principal: Fernandes, Patrícia érica
Data de Publicação: 2014
Tipo de documento: Tese
Idioma: por
Título da fonte: LOCUS Repositório Institucional da UFV
Texto Completo: http://locus.ufv.br/handle/123456789/510
Resumo: Silver nanoparticles (Ag-NPs) have been widely incorporated into various products such as textiles, household items, medical products, toiletries and food packaging because of its known antimicrobial activity and its broad spectrum of action. The antimicrobial effect of Ag-NPs is well established, however, their antimicrobial mechanism of action is not fully understood. Furthermore, it is important to better understand the effect of Ag-NP in microbial adhesion. The objectives of this study were 1) to determine the antimicrobial effect and probable mechanisms of action of Ag-NPs and Ag+ ions, from the silver nitrate (AgNO3), on species of gram-positive and gram-negative bacteria; 2) to determine the effect of subinhibitory concentrations of Ag-NPs and Ag+ ions on microbial adhesion, 3) characterize the inactivation kinetics of planktonic cells of Pseudomonas aeruginosa treated with Ag-NPs and Ag+ ions under different conditions. The Ag-NPs were synthesized with sodium citrate (Ag-NPC) or sodium borohydride (Ag-NPB) as reducing agents and coated with polyvinylpyrrolidone or carboxymethylcellulose. The characterization of Ag-NPs was made by spectroscopy in the ultraviolet and visible, dynamic light scattering (DLS), zeta potential (δ), transmission electron microscopy (TEM) and atomic absorption. Both Ag-NPs showed typical surface plasmon resonance, which confirmed their formation during the synthesis. The average particle size determined by DLS was 3.4 ± 1.2 nm for the Ag-NPC and 3.1 ± 0.9 nm for the Ag-NPB. The size of the Ag-NPC observed by TEM was 3.86 nm confirming the result obtained by DLS. The potential δ of Ag-NPC and Ag-NPB was - 31.9 ± 8.6 mV and - 33.2 ± 1.7 mV, respectively. Gram-negative bacteria are more sensitive to Ag-NPC and AgNO3 than gram-positive bacteria. The presence of Ag-NPC at subinhibitory concentrations decreased the adherence of P. aeruginosa onto polystyrene surfaces. However, subinhibitory concentrations of Ag-NPC or AgNO3 increased adhesion of gram-positive bacteria compared with the control group, probably in response to stress. Through Transmission Electron Microscopy / Energy Dispersive X-rays, it was observed that the silver penetrates in P. aeruginosa and Staphylococcus aureus cells and complex with sulfur and phosphorus, forming a condensation region in the center of the bacteria. Damage to S. aureus was less intense compared to the damage in P. aeruginosa. The Ag-NPC and the AgNO3 lost their antimicrobial activity in the presence of antioxidants agents, suggesting the involvement of reactive oxygen species (ROS) in its antimicrobial activity. However, it was not verified lipid peroxidation in cells treated with Ag-NPC or AgNO3. The results using dialysis membranes indicated that the antimicrobial activity of Ag-NPC is related to the release of Ag+ ions. The kinetics of inactivation of planktonic cells of P. aeruginosa was adjusted for biphasic model, which demonstrated heterogeneity in microbial resistance. The microbial inactivation time decreased with increasing of silver concentration and temperature. The antimicrobial activity of Ag-NPC and AgNO3 was reduced in culture medium compared to its activity in water, probably due to the complexation of Ag-NPC or AgNO3 with the medium constituents such as sulfur and phosphates.
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spelling Fernandes, Patrícia éricahttp://lattes.cnpq.br/1731807330753220Mantovani, Hilário Cuquettohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4727026Z7Silva, Luis Henrique Mendes dahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4728684Y0Andrade, Nélio José dehttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4788281Y5Pinto, Cláudia Lúcia de Oliveirahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4783521J6Bernardes, Patrícia Camposhttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4711525D72015-03-26T12:25:18Z2015-03-202015-03-26T12:25:18Z2014-08-01FERNANDES, Patrícia érica. Synthesis, characterization and antimicrobial action of silver nanoparticles. 2014. 101 f. Tese (Doutorado em Ciência de Alimentos; Tecnologia de Alimentos; Engenharia de Alimentos) - Universidade Federal de Viçosa, Viçosa, 2014.http://locus.ufv.br/handle/123456789/510Silver nanoparticles (Ag-NPs) have been widely incorporated into various products such as textiles, household items, medical products, toiletries and food packaging because of its known antimicrobial activity and its broad spectrum of action. The antimicrobial effect of Ag-NPs is well established, however, their antimicrobial mechanism of action is not fully understood. Furthermore, it is important to better understand the effect of Ag-NP in microbial adhesion. The objectives of this study were 1) to determine the antimicrobial effect and probable mechanisms of action of Ag-NPs and Ag+ ions, from the silver nitrate (AgNO3), on species of gram-positive and gram-negative bacteria; 2) to determine the effect of subinhibitory concentrations of Ag-NPs and Ag+ ions on microbial adhesion, 3) characterize the inactivation kinetics of planktonic cells of Pseudomonas aeruginosa treated with Ag-NPs and Ag+ ions under different conditions. The Ag-NPs were synthesized with sodium citrate (Ag-NPC) or sodium borohydride (Ag-NPB) as reducing agents and coated with polyvinylpyrrolidone or carboxymethylcellulose. The characterization of Ag-NPs was made by spectroscopy in the ultraviolet and visible, dynamic light scattering (DLS), zeta potential (δ), transmission electron microscopy (TEM) and atomic absorption. Both Ag-NPs showed typical surface plasmon resonance, which confirmed their formation during the synthesis. The average particle size determined by DLS was 3.4 ± 1.2 nm for the Ag-NPC and 3.1 ± 0.9 nm for the Ag-NPB. The size of the Ag-NPC observed by TEM was 3.86 nm confirming the result obtained by DLS. The potential δ of Ag-NPC and Ag-NPB was - 31.9 ± 8.6 mV and - 33.2 ± 1.7 mV, respectively. Gram-negative bacteria are more sensitive to Ag-NPC and AgNO3 than gram-positive bacteria. The presence of Ag-NPC at subinhibitory concentrations decreased the adherence of P. aeruginosa onto polystyrene surfaces. However, subinhibitory concentrations of Ag-NPC or AgNO3 increased adhesion of gram-positive bacteria compared with the control group, probably in response to stress. Through Transmission Electron Microscopy / Energy Dispersive X-rays, it was observed that the silver penetrates in P. aeruginosa and Staphylococcus aureus cells and complex with sulfur and phosphorus, forming a condensation region in the center of the bacteria. Damage to S. aureus was less intense compared to the damage in P. aeruginosa. The Ag-NPC and the AgNO3 lost their antimicrobial activity in the presence of antioxidants agents, suggesting the involvement of reactive oxygen species (ROS) in its antimicrobial activity. However, it was not verified lipid peroxidation in cells treated with Ag-NPC or AgNO3. The results using dialysis membranes indicated that the antimicrobial activity of Ag-NPC is related to the release of Ag+ ions. The kinetics of inactivation of planktonic cells of P. aeruginosa was adjusted for biphasic model, which demonstrated heterogeneity in microbial resistance. The microbial inactivation time decreased with increasing of silver concentration and temperature. The antimicrobial activity of Ag-NPC and AgNO3 was reduced in culture medium compared to its activity in water, probably due to the complexation of Ag-NPC or AgNO3 with the medium constituents such as sulfur and phosphates.Nanopartículas de prata (Ag-NPs) têm sido amplamente incorporadas em diversos produtos como têxteis, utensílios domésticos, produtos médicos, produtos de higiene pessoal e embalagens de alimentos, devido a sua conhecida atividade antimicrobiana e seu amplo espectro de ação. O efeito antimicrobiano das Ag-NPs é bem estabelecido, no entanto, seu mecanismo de ação antimicrobiana não está totalmente esclarecido. Além disso, é importante compreender melhor o efeito das Ag-NPs na adesão microbiana. Os objetivos desta pesquisa foram: 1) determinar o efeito antimicrobiano e os prováveis mecanismos de ação das Ag-NPs e dos íons Ag+, provenientes do nitrato de prata (AgNO3), sobre espécies de bactérias gram-positivas e gram-negativas, 2) determinar o efeito de concentrações subinibitórias de Ag-NPs e de íons Ag+ na adesão microbiana, 3) caracterizar a cinética de inativação de células planctônicas de Pseudomonas aeruginosa tratadas com Ag-NPs e com íons Ag+ sob diferentes condições. As Ag-NPs foram sintetizadas com citrato de sódio (Ag-NPC) ou borohidreto de sódio (Ag-NPB) como agentes redutores e revestidas com polivinilpirrolidona ou carboximetilcelulose. A caracterização das Ag-NPs foi feita por espectroscopia na região do ultravioleta e visível, espalhamento dinâmico de luz (DLS), potencial zeta (δ), microscopia eletrônica de transmissão (MET) e absorção atômica. Ambas Ag-NPs apresentaram ressonância plasmônica de superfície típica o que confirmou a formação das mesmas durante a síntese. O tamanho médio determinado por DLS foi 3,4 ± 1,2 nm para Ag-NPC e 3,1 ± 0,9 nm para as Ag-NPB. O tamanho das Ag-NPC observado por MET foi de 3,86 nm corroborando com o resultado obtido por DLS. O potencial δ das Ag-NPC e Ag-NPB foi de - 31,9 ± 8,6 mV e - 33,2 ± 1,7 mV, respectivamente. As bactérias gram-negativas foram mais sensíveis às Ag-NPC e ao AgNO3 do que as bactérias gram-positivas. A presença das Ag- NPC em concentrações subinibitórias diminuiu a adesão de P. aeruginosa em superfícies de poliestireno. Entretanto, concentrações subinibitórias de Ag-NPC ou AgNO3 aumentaram a adesão das bactérias gram-positivas em comparação com o grupo controle, provavelmente,em resposta ao estresse. Por meio de Microscopia Eletrônica de Transmissão/Energia Dispersiva de raios-X, observou-se que a prata penetra nas células de P. aeruginosa e de Staphylococcus aureus e complexa com enxofre e fósforo, formando-se uma região de condensação no centro das bactérias. Os danos causados em S. aureus foram menos intensos comparados aos danos provocados em P. aeruginosa. As Ag-NPC e o AgNO3 perderam a atividade antimicrobiana na presença de substâncias antioxidantes, sugerindo o envolvimento de espécies reativas de oxigênio (ERO) na sua atividade antimicrobiana. Entretanto, não foi verificada peroxidação de lipídeos nas células tratadas com Ag-NPC ou AgNO3. Os resultados utilizando-se membranas de diálise indicaram que a atividade antimicrobiana das Ag-NPC está relacionada com a liberação de íons Ag+. As cinéticas de inativação de células planctônicas de P. aeruginosa foram ajustadas por modelos bifásicos, o que demonstrou uma heterogeneidade na resistência microbiana. O tempo de inativação microbiana diminuiu com o aumento da concentração de prata e da temperatura. A atividade antimicrobiana das Ag-NPC e do AgNO3 foi reduzida em meio de cultura comparado com suas atividades em água, provavelmente, pela complexação das Ag-NPC ou do AgNO3 com os constituintes do meio, como enxofre e fosfatos.Conselho Nacional de Desenvolvimento Científico e Tecnológicoapplication/pdfporUniversidade Federal de ViçosaDoutorado em Ciência e Tecnologia de AlimentosUFVBRCiência de Alimentos; Tecnologia de Alimentos; Engenharia de AlimentosNanopartículasNanopartículas de prataEfeito antimicrobianoNanopartículas de prata - SíntesenanoparticlesSilver nanoparticlesAntimicrobial effectSilver nanoparticles - SummaryCNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOSSíntese, caracterização e ação antimicrobiana de nanopartículas de prataSynthesis, characterization and antimicrobial action of silver nanoparticlesinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/openAccessreponame:LOCUS Repositório Institucional da UFVinstname:Universidade Federal de Viçosa (UFV)instacron:UFVORIGINALtexto completo.pdfapplication/pdf1794395https://locus.ufv.br//bitstream/123456789/510/1/texto%20completo.pdfc57957de375df39b2ef72d50c8c586f3MD51TEXTtexto completo.pdf.txttexto completo.pdf.txtExtracted texttext/plain179197https://locus.ufv.br//bitstream/123456789/510/2/texto%20completo.pdf.txte5aa566e36cff3bff8e767befa0f6464MD52THUMBNAILtexto completo.pdf.jpgtexto completo.pdf.jpgIM Thumbnailimage/jpeg3483https://locus.ufv.br//bitstream/123456789/510/3/texto%20completo.pdf.jpg8b53173491f8a5dde5f1a0ee8280c50bMD53123456789/5102016-04-06 23:07:38.857oai:locus.ufv.br:123456789/510Repositório InstitucionalPUBhttps://www.locus.ufv.br/oai/requestfabiojreis@ufv.bropendoar:21452016-04-07T02:07:38LOCUS Repositório Institucional da UFV - Universidade Federal de Viçosa (UFV)false
dc.title.por.fl_str_mv Síntese, caracterização e ação antimicrobiana de nanopartículas de prata
dc.title.alternative.eng.fl_str_mv Synthesis, characterization and antimicrobial action of silver nanoparticles
title Síntese, caracterização e ação antimicrobiana de nanopartículas de prata
spellingShingle Síntese, caracterização e ação antimicrobiana de nanopartículas de prata
Fernandes, Patrícia érica
Nanopartículas
Nanopartículas de prata
Efeito antimicrobiano
Nanopartículas de prata - Síntese
nanoparticles
Silver nanoparticles
Antimicrobial effect
Silver nanoparticles - Summary
CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS
title_short Síntese, caracterização e ação antimicrobiana de nanopartículas de prata
title_full Síntese, caracterização e ação antimicrobiana de nanopartículas de prata
title_fullStr Síntese, caracterização e ação antimicrobiana de nanopartículas de prata
title_full_unstemmed Síntese, caracterização e ação antimicrobiana de nanopartículas de prata
title_sort Síntese, caracterização e ação antimicrobiana de nanopartículas de prata
author Fernandes, Patrícia érica
author_facet Fernandes, Patrícia érica
author_role author
dc.contributor.authorLattes.por.fl_str_mv http://lattes.cnpq.br/1731807330753220
dc.contributor.author.fl_str_mv Fernandes, Patrícia érica
dc.contributor.advisor-co1.fl_str_mv Mantovani, Hilário Cuquetto
dc.contributor.advisor-co1Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4727026Z7
dc.contributor.advisor-co2.fl_str_mv Silva, Luis Henrique Mendes da
dc.contributor.advisor-co2Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4728684Y0
dc.contributor.advisor1.fl_str_mv Andrade, Nélio José de
dc.contributor.advisor1Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4788281Y5
dc.contributor.referee1.fl_str_mv Pinto, Cláudia Lúcia de Oliveira
dc.contributor.referee1Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4783521J6
dc.contributor.referee2.fl_str_mv Bernardes, Patrícia Campos
dc.contributor.referee2Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4711525D7
contributor_str_mv Mantovani, Hilário Cuquetto
Silva, Luis Henrique Mendes da
Andrade, Nélio José de
Pinto, Cláudia Lúcia de Oliveira
Bernardes, Patrícia Campos
dc.subject.por.fl_str_mv Nanopartículas
Nanopartículas de prata
Efeito antimicrobiano
Nanopartículas de prata - Síntese
topic Nanopartículas
Nanopartículas de prata
Efeito antimicrobiano
Nanopartículas de prata - Síntese
nanoparticles
Silver nanoparticles
Antimicrobial effect
Silver nanoparticles - Summary
CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS
dc.subject.eng.fl_str_mv nanoparticles
Silver nanoparticles
Antimicrobial effect
Silver nanoparticles - Summary
dc.subject.cnpq.fl_str_mv CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS
description Silver nanoparticles (Ag-NPs) have been widely incorporated into various products such as textiles, household items, medical products, toiletries and food packaging because of its known antimicrobial activity and its broad spectrum of action. The antimicrobial effect of Ag-NPs is well established, however, their antimicrobial mechanism of action is not fully understood. Furthermore, it is important to better understand the effect of Ag-NP in microbial adhesion. The objectives of this study were 1) to determine the antimicrobial effect and probable mechanisms of action of Ag-NPs and Ag+ ions, from the silver nitrate (AgNO3), on species of gram-positive and gram-negative bacteria; 2) to determine the effect of subinhibitory concentrations of Ag-NPs and Ag+ ions on microbial adhesion, 3) characterize the inactivation kinetics of planktonic cells of Pseudomonas aeruginosa treated with Ag-NPs and Ag+ ions under different conditions. The Ag-NPs were synthesized with sodium citrate (Ag-NPC) or sodium borohydride (Ag-NPB) as reducing agents and coated with polyvinylpyrrolidone or carboxymethylcellulose. The characterization of Ag-NPs was made by spectroscopy in the ultraviolet and visible, dynamic light scattering (DLS), zeta potential (δ), transmission electron microscopy (TEM) and atomic absorption. Both Ag-NPs showed typical surface plasmon resonance, which confirmed their formation during the synthesis. The average particle size determined by DLS was 3.4 ± 1.2 nm for the Ag-NPC and 3.1 ± 0.9 nm for the Ag-NPB. The size of the Ag-NPC observed by TEM was 3.86 nm confirming the result obtained by DLS. The potential δ of Ag-NPC and Ag-NPB was - 31.9 ± 8.6 mV and - 33.2 ± 1.7 mV, respectively. Gram-negative bacteria are more sensitive to Ag-NPC and AgNO3 than gram-positive bacteria. The presence of Ag-NPC at subinhibitory concentrations decreased the adherence of P. aeruginosa onto polystyrene surfaces. However, subinhibitory concentrations of Ag-NPC or AgNO3 increased adhesion of gram-positive bacteria compared with the control group, probably in response to stress. Through Transmission Electron Microscopy / Energy Dispersive X-rays, it was observed that the silver penetrates in P. aeruginosa and Staphylococcus aureus cells and complex with sulfur and phosphorus, forming a condensation region in the center of the bacteria. Damage to S. aureus was less intense compared to the damage in P. aeruginosa. The Ag-NPC and the AgNO3 lost their antimicrobial activity in the presence of antioxidants agents, suggesting the involvement of reactive oxygen species (ROS) in its antimicrobial activity. However, it was not verified lipid peroxidation in cells treated with Ag-NPC or AgNO3. The results using dialysis membranes indicated that the antimicrobial activity of Ag-NPC is related to the release of Ag+ ions. The kinetics of inactivation of planktonic cells of P. aeruginosa was adjusted for biphasic model, which demonstrated heterogeneity in microbial resistance. The microbial inactivation time decreased with increasing of silver concentration and temperature. The antimicrobial activity of Ag-NPC and AgNO3 was reduced in culture medium compared to its activity in water, probably due to the complexation of Ag-NPC or AgNO3 with the medium constituents such as sulfur and phosphates.
publishDate 2014
dc.date.issued.fl_str_mv 2014-08-01
dc.date.accessioned.fl_str_mv 2015-03-26T12:25:18Z
dc.date.available.fl_str_mv 2015-03-20
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dc.identifier.citation.fl_str_mv FERNANDES, Patrícia érica. Synthesis, characterization and antimicrobial action of silver nanoparticles. 2014. 101 f. Tese (Doutorado em Ciência de Alimentos; Tecnologia de Alimentos; Engenharia de Alimentos) - Universidade Federal de Viçosa, Viçosa, 2014.
dc.identifier.uri.fl_str_mv http://locus.ufv.br/handle/123456789/510
identifier_str_mv FERNANDES, Patrícia érica. Synthesis, characterization and antimicrobial action of silver nanoparticles. 2014. 101 f. Tese (Doutorado em Ciência de Alimentos; Tecnologia de Alimentos; Engenharia de Alimentos) - Universidade Federal de Viçosa, Viçosa, 2014.
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