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Abstract(s)
Nos últimos tempos a procura pelos produtos de origem natural tem vindo a aumentar e,
como resultado, a procura por fibras têxteis naturais também tem aumentado. O Algodão é a
fibra têxtil mais importante devido à sua versatilidade, que faz com que este seja a fibra têxtil com maior número de aplicações. A necessidade de utilizar tecidos com propriedades antimicrobianas surgiu devido à necessidade de os proteger contra o apodrecimento causado por microrganismos. De facto, o crescimento de microrganismos nos têxteis apresenta uma série de efeitos indesejados, não apenas nos próprios têxteis mas também em quem os utiliza. Por estes motivos, é necessário que o crescimento dos microrganismos nos têxteis, durante o seu uso e armazenamento, seja minimizado. Para se seleccionar um agente antimicrobiano é necessário ter em conta algumas condições: eficácia contra um amplo espectro de bactérias e fungos, durabilidade do acabamento, baixa toxicidade para o utilizador e ambiente, o método de incorporação e a capacidade de fixação, e devem ser de baixo custo.
O objectivo deste trabalho consiste na obtenção de um material têxtil de algodão
funcionalizado com L-Cisteína (L-Cys) para obtenção de um efeito antibacteriano, com
potencial aplicação em materiais têxteis biomédicos, geriátricos e pediátricos. Para tal, testou-se a capacidade de ligação da L-Cisteína às fibras de algodão, com funcionalização por esgotamento e impregnação, com posterior análise da possível acção anti-microbiana sobre
Staphylococcus aureus e Klebsiella pneumoniae. Procedeu-se também à determinação da concentração mínima inibitória (MIC) do composto em causa para posterior comparação com a percentagem inibitória presente na fibra, e com a de outros biocidas já conhecidos. A inibição
do crescimento das estirpes mencionadas foi verificada de acordo com a Norma JIS L 1902-
2002. Efectuaram-se alguns ensaios de controlo da qualidade da fibra e do acabamento, nomeadamente ensaios de resistência ao rasgo e à lavagem. O ensaio de Ellman’s nas amostras e análise elementar por Energia Dispersiva de Raios X (EDX) permitiu confirmar a presença da L-Cisteína nas fibras de algodão. Recorreu-se ainda à técnica da citometria de fluxo para determinar o mecanismo de acção do composto em estudo sobre as estirpes seleccionadas.
Os resultados obtidos neste trabalho revelaram que este processo confere bioactividade ao material tratado, traduzida através de efeito antibacteriano em bactérias Gram positivas e Gram negativas, avaliado pela norma JIS L 1902-2002, com efeito permanente comprovado através dos ensaios de solidez à lavagem realizados. Foi possível verificar ainda que o mecanismo de acção da L-Cys sobre as bactérias em estudo reside na ocorrência de alterações na actividade metabólica destas bactérias, sendo também visível alguma despolarização de membrana.
Lately the demand for natural products has increased and as a result also the demand for natural fibers. Cotton fiber is the most important textile fiber because of its versatility, which makes this the textile fiber with a higher number of applications. The need for fabrics with antimicrobial properties arose from the need to protect fabrics against the rottenness caused by microorganisms. In fact, the growth of microorganisms in textiles has a number of undesirable effects, not only on textiles themselves, but also on who uses them. For these reasons it is necessary to minimize the growth of microorganisms in the textile during use and storage. To select an antimicrobial agent its necessary to make allowance of the conditions: effectiveness against a broad spectrum of bacteria and fungi, durability of the finishing treatment, low toxicity for the user and environment, the method of incorporation and fixation ability, and should be low cost. The aim of this work is to obtain a cotton textile material functionalized with L-Cysteine (LCys) to achieve an anti-microbial effect with potential application in biomedical, geriatric and pediatric textiles. For this purpose, the binding capacity of L-Cysteine on cotton fibers was tested, with functionalization by exhaustion and impregnation processes, and with subsequent analysis of possible anti-microbial action on Staphylococcus aureus and Klebsiella pneumoniae. It was also carried out the determination of minimum inhibitory concentration (MIC) of the compound for comparison with the inhibitory percentage present in the fiber, and further with other known biocides. Growth inhibition of mentioned bacteria was observed in accordance with standard JIS L 1902-2002. Some quality control tests of fiber and finishing were performed, including tests of resistance to tearing and washing, Ellman's assay in the samples and elemental analysis by Energy Dispersive X-ray (EDX) were performed to check the presence of L-Cysteine on cotton fibres. It was also used the technique of flow cytometry to determine the mechanism of action of L-Cys on the selected strains. The results of this study reveal that this process confers bioactivity to the treated fabric, represented by antibacterial effect on Gram positive and negative bacteria, measured by JIS L 1902-2002, with permanent effect demonstrated through tests of laundry fastness. It was also observed that the mechanism of action of L-Cys on the bacteria in question is the occurrence of changes in metabolic activity and is also visible a membrane depolarization of these bacteria.
Lately the demand for natural products has increased and as a result also the demand for natural fibers. Cotton fiber is the most important textile fiber because of its versatility, which makes this the textile fiber with a higher number of applications. The need for fabrics with antimicrobial properties arose from the need to protect fabrics against the rottenness caused by microorganisms. In fact, the growth of microorganisms in textiles has a number of undesirable effects, not only on textiles themselves, but also on who uses them. For these reasons it is necessary to minimize the growth of microorganisms in the textile during use and storage. To select an antimicrobial agent its necessary to make allowance of the conditions: effectiveness against a broad spectrum of bacteria and fungi, durability of the finishing treatment, low toxicity for the user and environment, the method of incorporation and fixation ability, and should be low cost. The aim of this work is to obtain a cotton textile material functionalized with L-Cysteine (LCys) to achieve an anti-microbial effect with potential application in biomedical, geriatric and pediatric textiles. For this purpose, the binding capacity of L-Cysteine on cotton fibers was tested, with functionalization by exhaustion and impregnation processes, and with subsequent analysis of possible anti-microbial action on Staphylococcus aureus and Klebsiella pneumoniae. It was also carried out the determination of minimum inhibitory concentration (MIC) of the compound for comparison with the inhibitory percentage present in the fiber, and further with other known biocides. Growth inhibition of mentioned bacteria was observed in accordance with standard JIS L 1902-2002. Some quality control tests of fiber and finishing were performed, including tests of resistance to tearing and washing, Ellman's assay in the samples and elemental analysis by Energy Dispersive X-ray (EDX) were performed to check the presence of L-Cysteine on cotton fibres. It was also used the technique of flow cytometry to determine the mechanism of action of L-Cys on the selected strains. The results of this study reveal that this process confers bioactivity to the treated fabric, represented by antibacterial effect on Gram positive and negative bacteria, measured by JIS L 1902-2002, with permanent effect demonstrated through tests of laundry fastness. It was also observed that the mechanism of action of L-Cys on the bacteria in question is the occurrence of changes in metabolic activity and is also visible a membrane depolarization of these bacteria.
Description
Keywords
Têxteis biomédicos Algodão - L-cisteína