Aplicação de nanopartículas de prata e titânio na melhoria das propriedades de filmes de alginato de sódio para uso em curativos
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Data
2018-03-28
Autores
Lima, Tiago Antônio de
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os curativos são agentes que, aplicados sobre uma lesão externa, auxiliam na cicatrização e cura; geralmente são de materiais leves, ordinariamente de algodão. A ideia de um curativo inteligente é fornecer um material leve, biocompátivel, biodegradável e anatômico que irá se adaptar perfeitamente para promover a cura de diferentes tipos de lesões. O objetivo deste trabalho foi melhorar as propriedades mecânicas e de barreiras em filmes de alginato de sódio. Desta forma, nanopartículas de prata com tamanho médio de 90 nm foram obtidas através de síntese química pela redução de nitrato de prata por borohidreto de sódio, e nanodispersão de dióxido de titânio obtida em equipamento de ultrassom. As nanopartículas foram inseridas na matriz de alginato juntamente com solução de sorbitol a 65%, e os filmes foram obtidos através do processo “Casting”. Posteriormente, o material foi caracterizado e os resultados das propriedades mecânicas de tensão por deformação revelaram que a presença de nanoemulsão de titânio (TiNE) e nanopartículas de prata (AgNP) na matriz de alginato aumentou a resistência à tração em aproximadamente 6,4 e 14,3%, respectivamente. Já nos filmes que tinham sorbitol, foi reduzida em 55,5%. Em contrapartida, a deformação foi aumentada em cerca de 1 a 3%. A estabilidade térmica dos filmes também sofreu um aumento (comprovada pelas técnicas de DSC e TG). Estes efeitos no aumento do elongamento e estabilidade térmica podem estar associados à formação de uma estrutura semelhante a uma micela, com regiões mais compactas em torno das NPs metálicas e regiões com espalhamento das cadeias poliméricas com predominância de monômeros M devido ao efeito de repulsão eletrostática, justificando o aumento na quantidade de poros na matriz, comprovado pelo aumento na permeabilidade ao vapor de água. Além disso, os filmes que continham AgNPs apresentaram atividade contra E. coli e S. aureus, com um pouco mais de efetividade nas amostras que continham sorbitol. Diante dos resultados apresentados, os filmes desenvolvidos neste trabalho apresentam potencial para aplicação como substitutos aos tradicionais curativos aplicados em lesões tópicas.
Dressings are agents that, applied on an external lesion, aid and healing; Usually they are of light materials, ordinarily of cotton. The idea of an intelligent dressing is to provide a light, biocompatible, biodegradable and anatomical material that will fit perfectly to promote healing of different types of lesions. The objective of this work was to improve the mechanical and barrier properties of sodium alginate films. In this way, silver nanoparticles (AgNP) with a mean size of 75-96 nm were obtained through chemical synthesis by reduction of silver nitrate by sodium borohydride, and titanium dioxide nanoemulsion (TiNE) by dispersion in ultrasonic equipment. Through the casting process, the nanoparticles were inserted into the alginate matrix together with 65% sorbitol solution. Subsequently, the material was characterized and the results of the tensile tests revealed that the presence of TiNE and AgNP in the alginate matrix increased the tensile strength by approximately 6.4 and 14.3% respectively. In the films that had sorbitol, it was reduced by 55.5%. In contrast, the elongation rate was increased about 1 to 3%. The thermal stability of the films also increased (as evidenced by DSC and TG techniques). These effects on increasing elongation and thermal stability may be associated with the formation of a spider-like structure with more compact regions around metal NPs and regions with polymer chain spreading with predominance of M monomers due to the eletrostatic repulsion effect, justifying the increase in the number of pores in the matrix, evidenced by the increase in the permeability to water vapor. In addition, the films containing AgNPs showed activity against E. coli and S. aureus, with a little more effectiveness in the samples containing sorbitol. Considering the results presented, the films developed in this work have promising potential for application as substitutes for the traditional dressings applied in topical lesions.
Dressings are agents that, applied on an external lesion, aid and healing; Usually they are of light materials, ordinarily of cotton. The idea of an intelligent dressing is to provide a light, biocompatible, biodegradable and anatomical material that will fit perfectly to promote healing of different types of lesions. The objective of this work was to improve the mechanical and barrier properties of sodium alginate films. In this way, silver nanoparticles (AgNP) with a mean size of 75-96 nm were obtained through chemical synthesis by reduction of silver nitrate by sodium borohydride, and titanium dioxide nanoemulsion (TiNE) by dispersion in ultrasonic equipment. Through the casting process, the nanoparticles were inserted into the alginate matrix together with 65% sorbitol solution. Subsequently, the material was characterized and the results of the tensile tests revealed that the presence of TiNE and AgNP in the alginate matrix increased the tensile strength by approximately 6.4 and 14.3% respectively. In the films that had sorbitol, it was reduced by 55.5%. In contrast, the elongation rate was increased about 1 to 3%. The thermal stability of the films also increased (as evidenced by DSC and TG techniques). These effects on increasing elongation and thermal stability may be associated with the formation of a spider-like structure with more compact regions around metal NPs and regions with polymer chain spreading with predominance of M monomers due to the eletrostatic repulsion effect, justifying the increase in the number of pores in the matrix, evidenced by the increase in the permeability to water vapor. In addition, the films containing AgNPs showed activity against E. coli and S. aureus, with a little more effectiveness in the samples containing sorbitol. Considering the results presented, the films developed in this work have promising potential for application as substitutes for the traditional dressings applied in topical lesions.
Descrição
Palavras-chave
Alginato de sódio, Nanopartículas de prata, Dióxido de titânio, Curativos, Sodium alginate, Silver nanoparticles, Titanium dioxide, Dressings