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Preparation and characterization of sericin nanoparticles with a new natural cross-linker
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A sericina é uma proteína hidrofílica derivada da seda. Devido às suas características, esta proteina tem sido extensivamente estudada para produzir nanopartículas biodegradáveis, biocompatíveis e não imunogénicas capazes de encapsular fármacos hidrofílicos e hidrofóbicos. Muitas vezes, é necessário o uso de um cross-linker na sua preparação para melhorar suas características físicas e químicas de modo a ser um sistema de veiculação de fármacos aceitável. O glutaraldeído é um bom cross-linker químico, no entanto, é importante ter em consideração a toxicidade deste composto. Na busca de novas moléculas, foi encontrado um novo agente reticulante natural, um caratonoide, capaz de realizar uma reação de cross-link e usado em sistemas de veiculação de fármacos como as nanopartículas de sericina. O objetivo deste trabalho foi preparar e caracterizar nanopartículas de sericina utilizando o novo Agente Reticulante Natural. Para isso, foi avaliada a sua estabilidade durante 4 semanas, à temperatura ambiente e a 4ºC pelo método Dynamic Light Scattering (DLS). Também foi determinado o rendimento da reação de reticulação da sericina utilizada na preparação de nanopartículas pela evaporação do sobrenadante e encapsulamento de soluções com 5% e 20% de curcumina, avaliando a fluorescência e a quantidade de fármaco encapsulado através de métodos de espectroscopia. Os resultados obtidos demonstraram que o tamanho e o indíce de polidispersão aumentaram ao longo do tempo, indicando uma agregação de partículas, uma melhor estabilidade quando armazenadas a temperatura ambiente tendo 78% da sericina sofrido crosslinking com o Agente Reticulante Natural, produzindo nanopartículas. Foi possível monitorizar as nanoparticulas graças à emissão de fluorescência por parte da curcumina. Foi determinado que na presença de água há uma diminuição da intensidade da fluorescência e a solução de 5% apresentou os melhores resultados ao incorporar cerca de 26% do composto. Estes resultados sugerem que este Agente Reticulante Natural pode ser um agente reticulante promissor na preparação de nanopartículas de sericina, no entanto, são necessários mais estudos para caracterizá-las adequadamente.
Sericin is a hydrophilic protein derived from silk. Because of its characteristics, this protein has been extensively studied to produce biodegradable, biocompatible and non-immunogenic nanoparticles that are able to encapsulate hydrophilic and hydrophobic drugs. Sometimes, it is necessary the use of a cross-linker in the preparation of nanoparticles to improve their physical and chemical characteristics to become a better drug delivery system. Glutaraldehyde is a good chemical cross-linker, however, it is important to have into consideration the toxicity of this compound. In the search of new molecules, it was found a new natural cross-linker, a carotenoid, that is able to perform a crosslinking reaction and be used in sericin-based nanoparticulate drug delivery systems. The aim of this work was to prepare and characterize sericin nanoparticles using the new Natural Crosslinker. For this purpose, its stability was evaluated for 4 weeks at room temperature and at 4ºC by the Dynamic Light Scattering (DLS) method. It was also determined the yield of crosslinked sericin used in the preparation of nanoparticles by evaporation of the supernatant and encapsulation of solutions containing 5% and 20% of curcumin, evaluating the fluorescence and the amount of drug encapsulated through methods of spectroscopy. The results proved that the size and the polydispersity index increased over time, indicating particle aggregation, better stability when stored at room temperature and 78% of the sericin was able to cross-link with the Natural Crosslinker, producing nanoparticles. Nanoparticles can be monitored thanks to curcumin's fluorescence emission. It was determined that, in presence of water, there was a decrease in fluorescence intensity and the 5% solution showed better results by incorporating about 26% of the compound. These results suggest that this Natural Cross-linker can be a promising cross-linker in the preparation of sericin nanoparticles, however, further studies are necessary in order to characterize them properly.
Sericin is a hydrophilic protein derived from silk. Because of its characteristics, this protein has been extensively studied to produce biodegradable, biocompatible and non-immunogenic nanoparticles that are able to encapsulate hydrophilic and hydrophobic drugs. Sometimes, it is necessary the use of a cross-linker in the preparation of nanoparticles to improve their physical and chemical characteristics to become a better drug delivery system. Glutaraldehyde is a good chemical cross-linker, however, it is important to have into consideration the toxicity of this compound. In the search of new molecules, it was found a new natural cross-linker, a carotenoid, that is able to perform a crosslinking reaction and be used in sericin-based nanoparticulate drug delivery systems. The aim of this work was to prepare and characterize sericin nanoparticles using the new Natural Crosslinker. For this purpose, its stability was evaluated for 4 weeks at room temperature and at 4ºC by the Dynamic Light Scattering (DLS) method. It was also determined the yield of crosslinked sericin used in the preparation of nanoparticles by evaporation of the supernatant and encapsulation of solutions containing 5% and 20% of curcumin, evaluating the fluorescence and the amount of drug encapsulated through methods of spectroscopy. The results proved that the size and the polydispersity index increased over time, indicating particle aggregation, better stability when stored at room temperature and 78% of the sericin was able to cross-link with the Natural Crosslinker, producing nanoparticles. Nanoparticles can be monitored thanks to curcumin's fluorescence emission. It was determined that, in presence of water, there was a decrease in fluorescence intensity and the 5% solution showed better results by incorporating about 26% of the compound. These results suggest that this Natural Cross-linker can be a promising cross-linker in the preparation of sericin nanoparticles, however, further studies are necessary in order to characterize them properly.
Descrição
Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, Universidade de Lisboa, Faculdade de Farmácia, 2019
Palavras-chave
Nanoparticles Sericin Natural Cross-linker Curcumin Mestrado Integrado - 2019