Publicação
Development of a bioactive membrane against vaginal infections based in a chitin-derivative
| Resumo: | This work focuses on the valorization of residues, in this case, the crayfish by using it as raw material in the process of chitosan extraction. It also involves a study of the characteristics and properties of chitosan, to develop a membrane for the treatment of vaginal infections. The first step was the extraction of chitin from the crayfish shell. This was done using a chemical extraction method, characterized by successive reactions at different temperatures. The reactions consist in extracting the pigment astaxanthin with acetic acid, bleaching with NaClO, HCl solution for demineralization, and finally deproteinization with NaOH. The result was chitin, dried for 24 h at 50 ºC. This process had a yield of 8.42±3.35%. The extracted chitin was characterized with FTIR analysis and presents an acetylation degree of 97.6±0.2 %. Additionally, by acid hydrolysis, the percentage of pure chitin in female and male crayfish samples was determined. Females presented a higher percentage. Proceeded to the transformation of chitin into chitosan, and characterization. The deacetylation of chitosan was optimized, occurring NaOH solution in a ratio of 1:15 (m of chitin / v of NaOH solution), 5 h in a thermal bath at 100 ºC, and then 5 h at 130 ºC. The yield of this process was 63.4 ± 18.4 %, and the chitosan obtained presented a degree of deacetylation of 64.5 ± 0.2 %. A physical-chemical characterization using FTIR, DSC, XRD, and zeta-potential analysis was carried out. Bioactivities properties, antioxidant, and antimicrobial were evaluated. The microorganisms tested and for which it showed any antimicrobial capacity were gram-positive bacteria (methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus), gram-negative (Escherichia coli), and fungi (Candida albicans).It was decided to develop an application in the field of biomedicine, exploring its potential as an antimicrobial agent. The final phase consisted of the production of chitosan membranes for the treatment of vaginal infections. It required the evaluation of their behavior, absorption, and degradation after immersion in a simulated vaginal fluid solution. The antimicrobial activity was also evaluated for typical pathogens of vaginal infections, and against Lactobacillus spp., common in the vaginal microbiota. The membranes produced with chitosan extracted from crayfish inhibited the growth of microorganisms. They also inhibited Lactobacillus spp., and, for this reason, the addition of probiotics/prebiotics in the formulation of the membranes is suggested. The membranes proved to be promising, being necessary adaptations, optimization of the production. |
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| Autores principais: | Conde, Alexandra Pereira |
| Assunto: | Crayfish Chitin Chitosan Extraction Characterization Bioactivities Membranes Vaginal infections |
| Ano: | 2022 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | This work focuses on the valorization of residues, in this case, the crayfish by using it as raw material in the process of chitosan extraction. It also involves a study of the characteristics and properties of chitosan, to develop a membrane for the treatment of vaginal infections. The first step was the extraction of chitin from the crayfish shell. This was done using a chemical extraction method, characterized by successive reactions at different temperatures. The reactions consist in extracting the pigment astaxanthin with acetic acid, bleaching with NaClO, HCl solution for demineralization, and finally deproteinization with NaOH. The result was chitin, dried for 24 h at 50 ºC. This process had a yield of 8.42±3.35%. The extracted chitin was characterized with FTIR analysis and presents an acetylation degree of 97.6±0.2 %. Additionally, by acid hydrolysis, the percentage of pure chitin in female and male crayfish samples was determined. Females presented a higher percentage. Proceeded to the transformation of chitin into chitosan, and characterization. The deacetylation of chitosan was optimized, occurring NaOH solution in a ratio of 1:15 (m of chitin / v of NaOH solution), 5 h in a thermal bath at 100 ºC, and then 5 h at 130 ºC. The yield of this process was 63.4 ± 18.4 %, and the chitosan obtained presented a degree of deacetylation of 64.5 ± 0.2 %. A physical-chemical characterization using FTIR, DSC, XRD, and zeta-potential analysis was carried out. Bioactivities properties, antioxidant, and antimicrobial were evaluated. The microorganisms tested and for which it showed any antimicrobial capacity were gram-positive bacteria (methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus), gram-negative (Escherichia coli), and fungi (Candida albicans).It was decided to develop an application in the field of biomedicine, exploring its potential as an antimicrobial agent. The final phase consisted of the production of chitosan membranes for the treatment of vaginal infections. It required the evaluation of their behavior, absorption, and degradation after immersion in a simulated vaginal fluid solution. The antimicrobial activity was also evaluated for typical pathogens of vaginal infections, and against Lactobacillus spp., common in the vaginal microbiota. The membranes produced with chitosan extracted from crayfish inhibited the growth of microorganisms. They also inhibited Lactobacillus spp., and, for this reason, the addition of probiotics/prebiotics in the formulation of the membranes is suggested. The membranes proved to be promising, being necessary adaptations, optimization of the production. |
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