Atividade antimicrobiana de miconanopartículas de dióxido de titânio
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2022-01-25
Autores
Silva, Carolina Assis da
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Universidade Estadual Paulista (Unesp)
Resumo
O dióxido de titânio possui capacidade de reflexão e absorção de UVA/UVB e tolerância adequada à pele humana. Devido a estas características, os filtros solares inorgânicos possuem em sua complexa composição nanopartículas de dióxido de titânio (TiO2NP). Este nanomaterial metálico (NM) é produzido em escala industrial por vias físico-químicas. Contudo, a necessidade de desenvolver novas abordagens para a síntese deste NM é iminente, uma vez que, os métodos utilizados produzem um grande volume de resíduos tóxicos e os NM obtidos possuem elevado índice de compostos tóxicos aderidos em sua superfície. Diante desta demanda, a nanotecnologia verde tem dentre muitos objetivos reduzir a presença de resíduos gerados ao longo da síntese, implementar processos sustentáveis e ampliar a biocompatibilidade destes compostos. Diferentes organismos são propostos neste tipo de abordagem, contudo os fungos filamentosos são os mais promissores. Neste contexto, o presente trabalho tem como objetivo estudar atividade antimicrobiana de duas miconanopartículas de TiO2, presentes em suspensão e encapsuladas em alginato e, também, avaliar potenciais efeitos tóxicos sobre microalga marinha Chlorella minutissima e microalga de água doce Chlorella fusca. As TiO2NP, foram caracterizadas por espectrofotometría UV-vis, ‘Dynamic Light Scattering’ (DLS) e Índice de polidispersão (PDI). A atividade antimicrobiana foi avaliada por concentração mínima inibitória utilizando as bactérias patogênicas Escherichia coli, Pseudomonas aeruginosa e Staphylococcus aureus. As microalgas Chlorella minutissima e Chlorella fusca foram utilizadas para estudos de densidade celular. A resposta antibacteriana da nanopartícula biológica de TiO2NP (bio-TiO2NP) em suspensão não apresentou resultados de inibição contra as bactérias patogênicas, já a bio-TiO2NP imobilizada tanto em 24h quanto 48h, inibiu ±80% da E.coli. Em relação aos ensaios de fitotoxicidade em microalgas, as duas espécies tiveram resposta tóxica, porém entre a bio-TiO2NP e a nanopartícula sintética P25, tanto na C. minutissima quanto na C. fusca, a bio-TiO2NP apresentou menos toxicidade do que a nanopartícula sintética P25. Visto isso, a possibilidade da substituição de TiO2NP sintéticas por biológicas, origem fúngica, representa ser uma alternativa promissora e que atende a Agenda 2030 para o Desenvolvimento Sustentável nos Objetivos (12) Assegurar padrões de produção e de consumo sustentáveis e (13) Tomar medidas urgentes para combater a mudança do clima e seus impactos.
Titanium dioxide has UVA/UVB reflection and absorption capacity and adequate tolerance to human skin. Due to these characteristics, inorganic sunscreens have titanium dioxide nanoparticles (TiO₂NP) in their complex composition. This metallic nanomaterial (MN) is produced on an industrial scale by physical-chemical means. However, the necessity to develop new approaches for the synthesis of this MN is imminent, since the methods used produce a large volume of toxic residues and the MN obtained have a high rate of toxic compounds adhered to their surface. Given this demand, green nanotechnology has among many objectives to reduce the presence of residues generated during the synthesis, implement sustainable processes and increase the biocompatibility of these compounds. Different organisms are proposed in this type of approach, however filamentous fungi are the most promising. In this context, the present work aims to study the antimicrobial activity of two myconanoparticles of TiO₂, present in suspension and encapsulated in alginate, and also to evaluate potential toxic effects on the marine microalgae Chlorella minutissima and the freshwater microalgae Chlorella fusca. TiO₂NPs were characterized by UV-vis spectrophotometry, 'Dynamic Light Scattering' (DLS) and Polydispersity Index (PDI). Antimicrobial activity was evaluated by minimum inhibitory concentration using the pathogenic bacteria Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The microalgae Chlorella minutissima and Chlorella fusca were used for cell density studies.The antibacterial response of the biological nanoparticle of TiO₂ (bio-TiO₂NP) in suspension did not show inhibition results against pathogenic bacteria, whereas bio-TiO₂NP immobilized both at 24h and 48h, inhibited ±80% of E.coli. In relation to phytotoxicity assays in microalgae, both species had a toxic response, but between bio-TiO₂NP and synthetic nanoparticle P25, both in C. minutissima and in C. fusca, bio-TiO₂NP showed less toxicity than the nanoparticle synthetic P25. In view of this, the possibility of replacing synthetic TiO₂NP with biological ones, of fungal origin, represents a promising alternative that meets the 2030 Agenda for Sustainable Development in the Goals (12) Ensure sustainable production and consumption patterns and (13) Take urgent measures to combat climate change and its impacts.
Titanium dioxide has UVA/UVB reflection and absorption capacity and adequate tolerance to human skin. Due to these characteristics, inorganic sunscreens have titanium dioxide nanoparticles (TiO₂NP) in their complex composition. This metallic nanomaterial (MN) is produced on an industrial scale by physical-chemical means. However, the necessity to develop new approaches for the synthesis of this MN is imminent, since the methods used produce a large volume of toxic residues and the MN obtained have a high rate of toxic compounds adhered to their surface. Given this demand, green nanotechnology has among many objectives to reduce the presence of residues generated during the synthesis, implement sustainable processes and increase the biocompatibility of these compounds. Different organisms are proposed in this type of approach, however filamentous fungi are the most promising. In this context, the present work aims to study the antimicrobial activity of two myconanoparticles of TiO₂, present in suspension and encapsulated in alginate, and also to evaluate potential toxic effects on the marine microalgae Chlorella minutissima and the freshwater microalgae Chlorella fusca. TiO₂NPs were characterized by UV-vis spectrophotometry, 'Dynamic Light Scattering' (DLS) and Polydispersity Index (PDI). Antimicrobial activity was evaluated by minimum inhibitory concentration using the pathogenic bacteria Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The microalgae Chlorella minutissima and Chlorella fusca were used for cell density studies.The antibacterial response of the biological nanoparticle of TiO₂ (bio-TiO₂NP) in suspension did not show inhibition results against pathogenic bacteria, whereas bio-TiO₂NP immobilized both at 24h and 48h, inhibited ±80% of E.coli. In relation to phytotoxicity assays in microalgae, both species had a toxic response, but between bio-TiO₂NP and synthetic nanoparticle P25, both in C. minutissima and in C. fusca, bio-TiO₂NP showed less toxicity than the nanoparticle synthetic P25. In view of this, the possibility of replacing synthetic TiO₂NP with biological ones, of fungal origin, represents a promising alternative that meets the 2030 Agenda for Sustainable Development in the Goals (12) Ensure sustainable production and consumption patterns and (13) Take urgent measures to combat climate change and its impacts.
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Fungo filamentoso, Escherichia coli, Chlorella minutissima, Chlorella fusca, Imobilização, Nanopartículas, Dióxido de titânio