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Abstract(s)
A pectina, é um polímero natural que apresenta vantagens como biodegradabilidade,
solubilidade em água, baixa toxicidade e propriedades bioadesivas. Estas vantagens
convertem-na numa forte candidata a ser utilizada em aplicações biomédicas.
Deste modo, o objetivo deste trabalho teve por base a produção de fibras de Pectina
através de electrospinning. No entanto, apesar da sua utilização ser vantajosa, a pectina
apresentou uma fraca electrospinnability, que é provocada pelas cargas elétricas,
nomeadamente pelas forças repulsivas existentes entre os polianiões. Desta forma, para
inverter esta dificuldade adicionou-se um polímero sintético, o poli (vinil álcool) (PVA).
A adição do PVA resultou numa mistura com as características desejáveis, uma vez
que a interação entre o PVA e as cadeias poliméricas da Pectina reduziu as forças repulsivas
existentes. Assim, aumentou substancialmente a electrospinnability da Pectina e
consequentemente foram produzidas as nanofibras pretendidas.
A morfologia das nanofibras de Pectina/PVA obtidas a partir do electrospinning
foram, posteriormente, analisadas por microscopia eletrónica de varrimento (SEM). O
resultado esperado verificou-se quando uma solução de 4% Pectina foi misturada com uma
solução 10% de PVA numa proporção 30:70 (v/v), respetivamente. Nesta proporção observouse
fibras uniformes e homogéneas com diâmetro de 287 nm.
Posteriormente, a L-Cisteína foi adicionada à solução Pectina/PVA 30:70 (v/v). Esta
adição teve como objetivo avaliar a bioactividade da L-Cisteína na mistura. Para estimar a
quantidade de L-Cisteína a ser adicionada à mistura Pectina/PVA a sua concentração mínima
inibitória (MIC) foi determinada, através do método de microdiluição em caldo. Os valores de
MIC obtidos para a solução de Pectina/PVA 30:70 com L-Cisteína foram de 5 mg/ml para
Staphyloccocus aureus e de 10 mg/ml para Klebsiella pneumoniae. Estes valores, confirmam
que a L-Cisteína funciona como agente antimicrobiano, o que pode ser muito útil em
aplicações biomédicas.
Pectin, is a natural polymer that has advantages, such as biodegradability, water solubility, low toxicity and bio adhesive properties. These advantages becoming a strong candidate to be used in biomedical applications. Thus, the objective of this work was based on the fabrication of pectin fibers through electrospinning. However, although their use is advantageous, the pectin showed a low electrospinnability, which is caused by the electrical charges, particularly by repulsive forces among the polyanions. Thus, the order to invert this situation was addeded a synthetic polymer, poly (vinyl alcohol) (PVA). The addition of PVA resulted in a blend with the desired characteristics since the interaction between PVA and chains polymeric pectin it reduced the existing repulsive forces. Hence, electrospinnability of pectin increased substantially and consequently required nanofibers were produced. The morphology of nanofibers Pectin/PVA obtained from electrospinning were analyzed by Scan Electron Microscopy (SEM). The expected result was found when a solution of 4% pectin was mixed with a solution 10% PVA in a proportion of 30:70 (v/v), respectively. This proportion uniform and homogeneous fibers were observed with a diameter of 287 nm. Afterward, L-Cysteine was added to the pectin/PVA 30:70 (v/v) solution. This addition was aimed assess the bioactivity of L-Cysteine in the blend. To estimate the amount of LCysteine to be added in the Pectin/PVA blend its minimum inhibitory concentration (MIC) was determined by the broth microdilution test. The MIC values obtained for L-Cysteine of the pectin/PVA 30:70 solution were 5 mg/ml for Staphylococcus aureus and 10 mg/ml of Klebsiella pneumoniae. These values confirm that L-Cysteine acts as an antimicrobial agent, which can be very useful in biomedical applications.
Pectin, is a natural polymer that has advantages, such as biodegradability, water solubility, low toxicity and bio adhesive properties. These advantages becoming a strong candidate to be used in biomedical applications. Thus, the objective of this work was based on the fabrication of pectin fibers through electrospinning. However, although their use is advantageous, the pectin showed a low electrospinnability, which is caused by the electrical charges, particularly by repulsive forces among the polyanions. Thus, the order to invert this situation was addeded a synthetic polymer, poly (vinyl alcohol) (PVA). The addition of PVA resulted in a blend with the desired characteristics since the interaction between PVA and chains polymeric pectin it reduced the existing repulsive forces. Hence, electrospinnability of pectin increased substantially and consequently required nanofibers were produced. The morphology of nanofibers Pectin/PVA obtained from electrospinning were analyzed by Scan Electron Microscopy (SEM). The expected result was found when a solution of 4% pectin was mixed with a solution 10% PVA in a proportion of 30:70 (v/v), respectively. This proportion uniform and homogeneous fibers were observed with a diameter of 287 nm. Afterward, L-Cysteine was added to the pectin/PVA 30:70 (v/v) solution. This addition was aimed assess the bioactivity of L-Cysteine in the blend. To estimate the amount of LCysteine to be added in the Pectin/PVA blend its minimum inhibitory concentration (MIC) was determined by the broth microdilution test. The MIC values obtained for L-Cysteine of the pectin/PVA 30:70 solution were 5 mg/ml for Staphylococcus aureus and 10 mg/ml of Klebsiella pneumoniae. These values confirm that L-Cysteine acts as an antimicrobial agent, which can be very useful in biomedical applications.
Description
Keywords
Actividade Antimicrobiana Electrospinning Klebsiella Pneumoniae L-Cisteína Mic Nanofibras Pectina Pva Staphyloccocus Aureus