Nanoligas bimetálicas de prata/cobre em matriz de quitosana: síntese, caracterização e inibição microbiana
Data
2023-10-16
Autores
Montalto, Gabriel Siciliano 
Orientadores
Philadelphi, Laura Oliveira Péres
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A busca por (nano)materiais com propriedades antimicrobianas tem sido uma área de grande interesse na pesquisa científica e desenvolvimento tecnológico. Nanopartículas (NPs) de cobre (CuNP) e prata (AgNP) têm sido avaliadas por apresentarem elevada atividade contra bactérias, inclusive aqueles resistentes aos antibióticos convencionais. No entanto, o alto custo das AgNP e a baixa estabilidade cinética das CuNP em meio aquoso limitam o uso destes materiais. Neste contexto, duas abordagens podem ser exploradas: i) o uso de nanoligas do tipo Ag/CuNP buscando um efeito sinérgico entre os metais e ii) uso de polímeros como matriz de encapsulação. Outra alternativa para a estabilização de nanomateriais é o uso de polímeros naturais para estabilização e veiculação de nanopartículas destes metais. Assim, neste trabalho propõe-se a síntese de nanoligas Ag/CuNP no biopolímero quitosana, o qual atua como agente quelante de metais e apresenta propriedades antimicrobianas, biodegradáveis e biocompatíveis favoráveis ao uso desejado. As nanoligas Ag/CuNP em quitosana foram sintetizadas via processo de co-redução em diferentes proporções Ag/Cu em quitosana. A estabilidade destas nanopartículas foi acompanhada por espectrofotometria UV-Vis. Estas foram ainda caracterizadas por microscopia eletrônica de transmissão e termogravimetria. A atividade biocida foi avaliada contra as bactérias Staphylococcus aureus e Escherichia coli. Todas as nanoligas apresentaram significativa atividade de inibição destes patógenos. Portanto, pode-se concluir que a encapsulação de nanoligas Ag/Cu em quitosana traz uma abordagem promissora para a produção de nanomateriais antimicrobianos.
The search for (nano)materials with antimicrobial properties has been an area of great interest in scientific research and technological development. Copper (CuNP) and silver (AgNP) nanoparticles (NPs) have been evaluated for showing high activity against bacteria, including those resistant to conventional antibiotics. However, the high cost of AgNP and the low kinetic stability of CuNP in aqueous media limit the use of these materials. In this context, two approaches can be explored: i) the use of Ag/CuNP type nanoalloys seeking a synergistic effect between metals and ii) use of polymers as an encapsulation matrix. Another alternative for the stabilization of nanomaterials is the use of natural polymers to stabilize and transport nanoparticles of these metals. Therefore, this work proposes the synthesis of Ag/CuNP nanoalloys in the chitosan biopolymer, which acts as a metal chelating agent and presents antimicrobial, biodegradable and biocompatible properties favorable to the desired use. Ag/CuNP nanoalloys in chitosan were synthesized via co-reduction process at different Ag/Cu ratios in chitosan. The stability of these nanoparticles was monitored by UV-Vis spectrophotometry. These were further characterized by transmission electron microscopy and thermogravimetry. The biocidal activity was evaluated against the bacteria Staphylococcus aureus and Escherichia coli. All nanoalloys showed significant inhibition activity against these pathogens. Therefore, it can be concluded that the encapsulation of Ag/Cu nanoalloys in chitosan is a promising approach for the production of antimicrobial nanomaterials.
The search for (nano)materials with antimicrobial properties has been an area of great interest in scientific research and technological development. Copper (CuNP) and silver (AgNP) nanoparticles (NPs) have been evaluated for showing high activity against bacteria, including those resistant to conventional antibiotics. However, the high cost of AgNP and the low kinetic stability of CuNP in aqueous media limit the use of these materials. In this context, two approaches can be explored: i) the use of Ag/CuNP type nanoalloys seeking a synergistic effect between metals and ii) use of polymers as an encapsulation matrix. Another alternative for the stabilization of nanomaterials is the use of natural polymers to stabilize and transport nanoparticles of these metals. Therefore, this work proposes the synthesis of Ag/CuNP nanoalloys in the chitosan biopolymer, which acts as a metal chelating agent and presents antimicrobial, biodegradable and biocompatible properties favorable to the desired use. Ag/CuNP nanoalloys in chitosan were synthesized via co-reduction process at different Ag/Cu ratios in chitosan. The stability of these nanoparticles was monitored by UV-Vis spectrophotometry. These were further characterized by transmission electron microscopy and thermogravimetry. The biocidal activity was evaluated against the bacteria Staphylococcus aureus and Escherichia coli. All nanoalloys showed significant inhibition activity against these pathogens. Therefore, it can be concluded that the encapsulation of Ag/Cu nanoalloys in chitosan is a promising approach for the production of antimicrobial nanomaterials.