Síntese, caracterização e atividade antimicrobiana de filmes biopoliméricos de derivados de quitosana
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Data
2019-09-20
Autores
Alves, Anna Carolina Rodrigues Santos
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Universidade Estadual Paulista (Unesp)
Resumo
O biopolímero quitosana apresenta propriedades biológicas favoráveis, incluindo caráter antioxidante, antimicrobiana, baixa toxicidade, biodegradabilidade, biocompatibilidade, ação anti-inflamatória e capacidade de formar filmes, o que a torna um material de grande interesse. Visando à melhoria das propriedades desse biomaterial, o presente trabalho teve como objetivo realizar a síntese e caracterização de derivados anfifílicos de quitosana com potencial para formação de filmes. Os derivados foram obtidos a partir de quitosana comercial (CHC) previamente desacetilada (CHD) e despolimerizada (CHL), que foram submetidos à reação com o cloridrato de 2-cloro-N,N-dietiletilamina. O derivado hidrofílico obtido (DEAE-CHL) foi posteriormente modificado com o grupo dodecil aldeído por meio de reação de alquilação, resultando no derivado anfifílico de quitosana (DEAE-CHL-Dod). A massa molecular média foi determinada utilizando cromatografia de permeação em gel (CPG), e os valores obtidos foram de 208 kDa para CHC, 143 kDa para CHD, 11 kDa para CHL e 14 kDa para DEAE-CHL. O grau de desacetilação e os graus de substituições pelos grupos DEAE e Dod foram determinados por meio da técnica de espectroscopia de ressonância magnética nuclear de hidrogênio (RMN 1H). O grau de desacetilação da CHC foi de 77% e da CHD foi de 97%. Os graus de substituição por DEAE e Dod foram de 44 e 24%, respectivamente. Filmes de diferentes formulações dos polímeros foram produzidos com concentrações crescentes de dois agentes plastificantes, glicerol e sorbitol (5%, 10% e 20%) e foram caracterizados por suas propriedades estruturais, solubilidade, propriedades óticas, mecânicas, térmicas, permeabilidade ao vapor de água e antifúngicas. Por meio dos resultados obtidos, verificou-se que a composição química dos polímeros, a massa molecular e a presença de plastificantes influenciaram significativamente nas suas características e afetaram muito as propriedades mecânicas, espessura, cor e propriedades de barreira. O estudo antifúngico contra Aspergillus flavus, Alternaria alternata, Alternaria solani e Penicillium expansum mostraram que os filmes contendo os grupos DEAE e Dod exibiram maior atividade antifúngica que as quitosanas não modificadas. As propriedades mecânicas de filmes altamente solúveis foram melhoradas pelos plastificantes nas porcentagens de 5 e 10%, indicando esses derivados como potenciais candidatos para o revestimento de grãos e frutos de várias culturas.
Chitosan biopolymer has favorable biological characteristics, including antioxidant, antimicrobial characters, low toxicity, biodegradability, biocompatibility, antiinflammatory action and film display ability, or makes it a material of great interest. Aiming at improving the properties of this biomaterial, the present work aimed to characterize and characterize amphiphilic chitosan compounds with potential for film formation. The derivatives were taken from deacetylated (CHD) and depolymerized (CHL) commercial chitosan (CHC), which were reacted with 2-chloro-N,Ndiethylethylamine hydrochloride. The hydrophilic derivative used (DEAE-CHL) was further modified with the dodecyl aldehyde group by alkylation reaction, resulting in no amphiphilic chitosan derivative (DEAE-CHL-Dod). An average molecular weight gel permeation chromatography (CPG) was used, and the values were 208 kDa for CHC, 143 kDa for CHD, 11 kDa for CHL and 14 kDa for DEAE-CHL. The degree of deacetylation and the degree of substitution of the DEAE and Dod groups were used by the hydrogen nuclear magnetic resonance spectroscopy (1H NMR) technique. The degree of deacetylation of CHC was 77% and the CHD was 97%. The degrees of substitution of DEAE and Dod were 44 and 24%, respectively. Films of different polymer formulations were used with crescents of two plasticizing agents, glycerol and sorbitol (5%, 10% and 20%) and were characterized by their specific characteristics (IV and XRD), solubility, optical, mechanical, thermal properties. water vapor and antifungal permeability. Through the obtained results, it was verified that the chemical composition of the polymers, the molecular mass and the presence of plasticizers influenced the characteristics and greatly affect the mechanical characteristics, thickness, color and substance use. The antifungal study against Aspergillus flavus, Alternaria alternata, Alternaria solani, and Penicillium expansum shows that the films published by the DEAE and Dod groups exhibited higher antifungal activity than as unmodified chitosans. As mechanical properties of highly soluble films have been improved by plasticizers at 5 and 10% percentages, these rates are applied as a requirement for the coating of grains and fruits of various crops.
Chitosan biopolymer has favorable biological characteristics, including antioxidant, antimicrobial characters, low toxicity, biodegradability, biocompatibility, antiinflammatory action and film display ability, or makes it a material of great interest. Aiming at improving the properties of this biomaterial, the present work aimed to characterize and characterize amphiphilic chitosan compounds with potential for film formation. The derivatives were taken from deacetylated (CHD) and depolymerized (CHL) commercial chitosan (CHC), which were reacted with 2-chloro-N,Ndiethylethylamine hydrochloride. The hydrophilic derivative used (DEAE-CHL) was further modified with the dodecyl aldehyde group by alkylation reaction, resulting in no amphiphilic chitosan derivative (DEAE-CHL-Dod). An average molecular weight gel permeation chromatography (CPG) was used, and the values were 208 kDa for CHC, 143 kDa for CHD, 11 kDa for CHL and 14 kDa for DEAE-CHL. The degree of deacetylation and the degree of substitution of the DEAE and Dod groups were used by the hydrogen nuclear magnetic resonance spectroscopy (1H NMR) technique. The degree of deacetylation of CHC was 77% and the CHD was 97%. The degrees of substitution of DEAE and Dod were 44 and 24%, respectively. Films of different polymer formulations were used with crescents of two plasticizing agents, glycerol and sorbitol (5%, 10% and 20%) and were characterized by their specific characteristics (IV and XRD), solubility, optical, mechanical, thermal properties. water vapor and antifungal permeability. Through the obtained results, it was verified that the chemical composition of the polymers, the molecular mass and the presence of plasticizers influenced the characteristics and greatly affect the mechanical characteristics, thickness, color and substance use. The antifungal study against Aspergillus flavus, Alternaria alternata, Alternaria solani, and Penicillium expansum shows that the films published by the DEAE and Dod groups exhibited higher antifungal activity than as unmodified chitosans. As mechanical properties of highly soluble films have been improved by plasticizers at 5 and 10% percentages, these rates are applied as a requirement for the coating of grains and fruits of various crops.
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Palavras-chave
Quitosana, Biomaterial, Anfifílico, Filmes, Atividade antifúngica, Chitosan, Biomaterial, Amphiphilic, Films, Antifungal activity