Preparação de nanopartículas de prata e avaliação da sua ação antimicrobiana
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2020
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O termo "nano" não é novo, pois o uso de nanopartículas remonta aos tempos antigos. A evolução da nanotecnologia permitiu o melhor uso de agentes ativos para cosméticos, diagnóstico e tratamento. É sabido que as nanopartículas oferecem várias vantagens na indústria farmacêutica devido à sua capacidade de administrar medicamentos ou ativos corretamente, promover maior solubilidade e permeação da membrana, aumentar a afinidade pelos recetores e, em alguns casos, diminuir alguns efeitos colaterais adversos.
Mais especificamente, as nanopartículas de prata (AgNPs) têm sido consideradas agentes antibacterianos interessantes, pois proporcionam maior interação com a membrana celular e fácil penetração celular.
Existem diferentes métodos para produzir nanopartículas que podem ser de cima para baixo e de baixo para cima (denominados top-down e de bottom-up). No primeiro caso, as AgNPs podem ser sintetizados por métodos físicos, como ablação a laser, decomposição térmica, pirólise por spray ultrassónico, evaporação/condensação; e no segundo, as AgNPs são obtidas por materiais e reagentes de nível atómico, por métodos químicos ou biológicos.
Neste trabalho, três tipos de AgNPs foram obtidos por diferentes métodos usando a redução de borohidreto como agente redutor de prata: banho de gelo (método A), solução aquosa aquecida de NaBH4 (método B) e solução aquecida de AgNO3 (método C). Os AgNPs foram caracterizados em termos de espectros de absorção, tamanho médio, índice de polidispersividade e carga superficial. Então, a sua atividade biológica contra duas bactérias Gram-positivas S. aureus e Gram-negativas E. coli foi também avaliada.
De acordo com os resultados obtidos, o método utilizando borohidreto de sódio aquecido apresentou os maiores valores de inibição para S. aureus e E. coli.
The term “nano” is not new since the use of nanoparticles remotes to ancient times. The evolution of nanotechnology has enabled the better use of active agents for cosmetics, diagnosis and treatment. It is well known that nanoparticles offer several advantages in the pharmaceutical industry because of their ability to correctly deliver drugs or actives, to promote higher solubility and membrane permeation, to enhance the affinity for receptors and in some cases to decrease some adverse side effects. More especifically, silver nanoparticles (AgNPs) have been considered interesting antibacterial agents because they provide greater interaction with the cell membrane and easy cell penetration. There are different methods for producing nanoparticles that can be top-down and bottom-up. In the first case, the AgNPs may be synthesized by physical methods such as laser ablation, thermal decomposition, ultrasonic spray pyrolysis, evaporation/ condensation; and in the second, the AgNPs are obtained by atomic level materials and reagents, through chemical or biological methods. In this work, three types of AgNPs were obtained by different methods using borohydride reduction as reducing agent of silver: ice bath (method A), heated aqueous solution of NaBH4 (method B) and heated solution of AgNO3 (method C). AgNPs were characterized in terms of absorption spectra, mean size, polydispersity index and surface charge. Then, their biological activity against two bacteria Gram-positive S. aureus and Gram-negative E. coli. also evaluated. According to the results obtained, the method using heated sodium borohydride showed the highest inhibition values for S. aureus and E. coli.
The term “nano” is not new since the use of nanoparticles remotes to ancient times. The evolution of nanotechnology has enabled the better use of active agents for cosmetics, diagnosis and treatment. It is well known that nanoparticles offer several advantages in the pharmaceutical industry because of their ability to correctly deliver drugs or actives, to promote higher solubility and membrane permeation, to enhance the affinity for receptors and in some cases to decrease some adverse side effects. More especifically, silver nanoparticles (AgNPs) have been considered interesting antibacterial agents because they provide greater interaction with the cell membrane and easy cell penetration. There are different methods for producing nanoparticles that can be top-down and bottom-up. In the first case, the AgNPs may be synthesized by physical methods such as laser ablation, thermal decomposition, ultrasonic spray pyrolysis, evaporation/ condensation; and in the second, the AgNPs are obtained by atomic level materials and reagents, through chemical or biological methods. In this work, three types of AgNPs were obtained by different methods using borohydride reduction as reducing agent of silver: ice bath (method A), heated aqueous solution of NaBH4 (method B) and heated solution of AgNO3 (method C). AgNPs were characterized in terms of absorption spectra, mean size, polydispersity index and surface charge. Then, their biological activity against two bacteria Gram-positive S. aureus and Gram-negative E. coli. also evaluated. According to the results obtained, the method using heated sodium borohydride showed the highest inhibition values for S. aureus and E. coli.
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Orientação: Marisa Nicolai
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MESTRADO INTEGRADO EM CIÊNCIAS FARMACÊUTICAS, CIÊNCIAS FARMACÊUTICAS, NANOPARTÍCULAS, PRATA, NANOPARTÍCULAS DE PRATA, ANTIMICROBIANOS, PHARMACEUTICAL SCIENCES, NANOPARTICLES, SILVER, SILVER NANOPARTICLES, ANTIMICROBIAL