A carregar...
Publicação
Electrospinning of Polyvinyl alcohol Based Wound Dressing
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 2.34 MB | Adobe PDF |
Autores
Orientador(es)
Resumo(s)
O electrospinning é uma tecnologia que produz nanofibras com elevada porosidade, da ordem dos nanómetros, as quais podem ser utilizadas na cicatrização de feridas. Devido à hidrofilia e à não toxicidade do álcool polivinílico (cuja sigla em inglês é PVA), este polímero é largamente utilizado na produção de nanofibras. Este trabalho permite avaliar a influência de propriedades da solução, assim como de parâmetros do processo. Um dos objetivos deste trabalho consistiu na comparação da morfologia e diâmetro das nanofibras entre dois pesos moleculares: 67,000 e 130,000. Para além disso, procedeu-se à comparação da morfologia das nanofibras quando apenas tínhamos PVA puro e quando se adicionou o extrato de casca de bétula ao polímero. Este extrato foi adicionado ao PVA, uma vez que permite acelerar o processo de cicatrização. Relativamente aos resultados obtidos, estes demonstraram que o peso molecular e a concentração de PVA têm influência no diâmetro e na morfologia das nanofibras que foram submetidas ao processo de electrospinning. Quando estes dois parâmetros aumentaram, a morfologia destas foi alterada de beaded para estrutura uniforme e o diâmetro aumentou. Verificou-se também um aumento na viscosidade e na viscoelasticidade da solução, quando se aumentou o peso molecular e a concentração de PVA. Um aumento na voltagem aplicada e na taxa de fluxo também demonstrou ter efeito no diâmetro da fibra. De acordo com os resultados obtidos em todas as experiências, podemos concluir que o peso molecular de 130,000 provou ser o melhor, uma vez que a viscosidade é maior e origina fibras mais uniformes e com diâmetros maiores que o de 67,000. Em suma, nanofibras uniformes e contínuas de PVA e resultantes da junção deste polímero com o extrato de casca de bétula, foram submetidas a electrospinning com sucesso. Do ponto de vista farmacêutico, a adição de betulina (extrato de casca de bétula) à solução de PVA é mais vantajosa, uma vez que este extrato acelera o processo de cicatrização e possui propriedades antifúngicas e antibacterianas, prevenindo, assim, a entrada de microorganismos no tecido afetado. A utilização da tecnologia de electrospinning para produzir nanofibras com aplicação na cicatrização de feridas, é uma estratégia promissora, provando ser uma nova abordagem terapêutica.
Electrospinning is a technology that produces fibers with high porosity, in the nanometer range, that can be used to produce nanofibers for wound healing. Due to the hydrophilicity and non-toxicity of polyvinyl alcohol (PVA), this polymer is widely used for nanofiber production. This work aims to evaluate the influence of solution properties such as molecular weight of polymer, polymer concentration, viscosity, viscoelasticity and surface tension as well as processing parameters, such as flow rate, applied voltage and tip to collector distance. One of the objectives of this work consisted in the comparison of nanofiber morphology and diameter between two molecular weights of PVA: 67,000 and 130,000. Furthermore, a birch bark extract was added to the PVA polymer due to its healing properties and a nanofiber morphology comparison between pure PVA and PVA mixed the birch bark extract was performed. The results showed that molecular weight and PVA concentration had noteworthy influence on the fiber diameter and structural morphology of electrospun nanofibers. When these two parameters increased, the fiber morphology changed from beaded to uniform and the fiber diameter increased. It was also observed an increase in the viscosity and viscoelasticity of the solution, when PVA concentration and molecular weight increased. The increase in the applied voltage and flow rate has been found to affect the fiber diameter. According to the results obtained in all of these experiments, 130,000 was proved to be the best molecular weight since its viscosity was higher than 67,000 and the obtained fibers were smoother and with larger diameters than the lower molecular weight. Continuous uniform nanofibers of PVA and a blend of this polymer loaded with the birch bark extract were successfully electrospun. From a pharmaceutical point of view, adding betulin (birch bark extract) to the PVA solution was more advantageous, since this component accelerate the wound healing process and has anti-fungal and anti-bacterial properties, thus avoiding the access of microorganisms into the affected tissue. The use of electrospinning technology to produce nanofibers, and applying them as wound dressings for wound healing, is a promising strategy to provide a new therapeutic approach.
Electrospinning is a technology that produces fibers with high porosity, in the nanometer range, that can be used to produce nanofibers for wound healing. Due to the hydrophilicity and non-toxicity of polyvinyl alcohol (PVA), this polymer is widely used for nanofiber production. This work aims to evaluate the influence of solution properties such as molecular weight of polymer, polymer concentration, viscosity, viscoelasticity and surface tension as well as processing parameters, such as flow rate, applied voltage and tip to collector distance. One of the objectives of this work consisted in the comparison of nanofiber morphology and diameter between two molecular weights of PVA: 67,000 and 130,000. Furthermore, a birch bark extract was added to the PVA polymer due to its healing properties and a nanofiber morphology comparison between pure PVA and PVA mixed the birch bark extract was performed. The results showed that molecular weight and PVA concentration had noteworthy influence on the fiber diameter and structural morphology of electrospun nanofibers. When these two parameters increased, the fiber morphology changed from beaded to uniform and the fiber diameter increased. It was also observed an increase in the viscosity and viscoelasticity of the solution, when PVA concentration and molecular weight increased. The increase in the applied voltage and flow rate has been found to affect the fiber diameter. According to the results obtained in all of these experiments, 130,000 was proved to be the best molecular weight since its viscosity was higher than 67,000 and the obtained fibers were smoother and with larger diameters than the lower molecular weight. Continuous uniform nanofibers of PVA and a blend of this polymer loaded with the birch bark extract were successfully electrospun. From a pharmaceutical point of view, adding betulin (birch bark extract) to the PVA solution was more advantageous, since this component accelerate the wound healing process and has anti-fungal and anti-bacterial properties, thus avoiding the access of microorganisms into the affected tissue. The use of electrospinning technology to produce nanofibers, and applying them as wound dressings for wound healing, is a promising strategy to provide a new therapeutic approach.
Descrição
Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, Universidade de Lisboa, Faculdade de Farmácia, 2019
Palavras-chave
Álcool polivinílico Cicatrização de feridas Electrospinning Nanofibras. Mestrado Integrado - 2019