Síntese de zeólita Mordenita (MOR) utilizando radiação de micro-ondas e sua aplicação como potencial agente hemostático coagulante
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Data
2017-04-19
Autores
Zazeri, Gabriel [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Zeólitas são materiais policristalinos constituídos de aluminosilicatos que possuem sistemas de poros e cavidades, alta área superficial e carga negativa. Devido a essas propriedades físico-químicas, esses materiais podem ser utilizados como trocadores iônicos, peneiras moleculares, catalisadores heterogêneos e agentes hemostáticos coagulantes. No que diz respeito a aplicação desses materiais como agentes hemostáticos coagulantes, as propriedades físico-químicas descritas acima oferecem um ambiente favorável para que o processo de coagulação ocorra mais rapidamente, uma vez que as cargas negativas presentes na estrutura das zeólitas induzem o início da via intrínseca da cascata de coagulação, este fenômeno é conhecido como “glass effect”. Além disso, a alta área superficial facilita a adsorção de moléculas de água e como consequência, as proteínas e fatores coagulantes ficam concentrados facilitando o processo de formação do coágulo. O uso de nanozeólitas das famílias FAU e LTA como agente coagulante já foi reportado na literatura, no entanto não existem relatos de aplicação da nanozeólita MOR para tal finalidade. Sendo assim, um dos objetivos desta pesquisa foi avaliar o potencial coagulante desta zeolita. Para tanto, a síntese da nanozeólita é um processo fundamental e o desafio desta pesquisa foi reduzir o tempo de síntese e a escala do material utilizando a radiação de micro-ondas sem perder a cristalinidade e a pureza de fase. Para este estudo, a síntese da zeólita foi realizada seguindo a composição molar: 1Al2O3: 30SiO2: 6Na2O: 780H2O. O método utilizado para a síntese foi a técnica sol-gel e as fontes de aquecimento foram a convencional e a radiação de micro-ondas. O material sintetizado foi caracterizado pelas técnicas de difração de raios-X (DRX), microscopia eletrônica de varredura (MEV) e de alta ransmissão (MET), potencial Zeta, BET, Microscopia de contraste de fase e os parâmetros de coagulação sanguínea foram testados utilizando um tromboelastógrafo (TEG). Os padrões de difrações das zeólitas revelaram que foram necessários 4 dias de síntese utilizando a fonte de aquecimento convencional, enquanto que foram necessárias apenas 5 horas de síntese quando utilizado a radiação de micro-ondas. Os parâmetros de coagulação sanguínea obtidos pelo TEG revelaram que o sangue humano sem adição do material zeolítico inicia a formação do coágulo com 9,8 minutos, por outro lado, quando adicionado material zeolítico no sangue este parâmetro reduziu para 3,8 minutos. Além da redução de tempo para a formação de coágulo, os parâmetros de elasticidade da rede de fibrina e a geração de trombina também foram otimizados quando o material foi adicionado ao sangue.
Zeolites are alluminosilicate polycristalline materials with properties such as nanosized pores, channels and large surface area. Due to these physicochemical properties, zeolitic materials can be used as ion exchangers, molecular sieves, heterogenous catalysts and hemostatic coagulation agent. Concerning the application of zeolites as hemostatic agentes, mordenite zeolite has physicochemical properties that offer a favorable environment that makes coagulation more efficient, such as negative charges, that induce the initialization of intrinsic via of clot cascade, this phenomenon is known as glass effect. Furthermore, the high surface area makes the adsorption of water molecules more efficient which concentrates proteins and coagulant factors, thus accelerating the formation of clot. The application of nanozeolite FAU as hemostatic coagulation agent has been reported in the literature, nevertheless as far as it’s concerned, nanozeolite MOR hasn’t been reported for this application. Therefore one of this research objectives was evaluate the hemostatic coagulation potential of nanozeolite MOR and to reach this objective, the synthesis of the material was fundamental. However the challenge of this research was decrease the synthesis time and decrease the size of material using microwave radiation without lose the cristalinity and phase purity. For this study, mordenite zeolite was synthetized with the following gel composition: 1Al2O3: 30SiO2: 6Na2O: 780H2O. The method used for the synthesis was sol-gel technique and the heat sources were both hidrothermal and microwave heating. The synthetized material was characterized by X-rays diffraction (XRD), scanning electron microscopy (SEM), High resolution transmission eléctron microscopy (HRTEM), Zeta potential, BET and Phase contrast microscopy. Thromboelastography (TEG) test in vitro was employed to determine the clotting efficiency of the made zeolite when it is in contact with blood. X-Rays diffraction patterns showed that synthesis employing conventional heating took 4 days to yield mordenite zeolite whereas employing microwave heating this synthesis time was decreased to 5 hours. The TEG profile and clotting parameters revealed that without the addition of zeolites, human blood begins to clot at about 9,8 minutes. Adding zeolites to the human blood, regardless of heating source employed, has decreased the clotting time to 3,8 minutes. Elastic properties of the formed clots by using mordenite zeolite as hemostatic agents and thrombin generation were also improved.
Zeolites are alluminosilicate polycristalline materials with properties such as nanosized pores, channels and large surface area. Due to these physicochemical properties, zeolitic materials can be used as ion exchangers, molecular sieves, heterogenous catalysts and hemostatic coagulation agent. Concerning the application of zeolites as hemostatic agentes, mordenite zeolite has physicochemical properties that offer a favorable environment that makes coagulation more efficient, such as negative charges, that induce the initialization of intrinsic via of clot cascade, this phenomenon is known as glass effect. Furthermore, the high surface area makes the adsorption of water molecules more efficient which concentrates proteins and coagulant factors, thus accelerating the formation of clot. The application of nanozeolite FAU as hemostatic coagulation agent has been reported in the literature, nevertheless as far as it’s concerned, nanozeolite MOR hasn’t been reported for this application. Therefore one of this research objectives was evaluate the hemostatic coagulation potential of nanozeolite MOR and to reach this objective, the synthesis of the material was fundamental. However the challenge of this research was decrease the synthesis time and decrease the size of material using microwave radiation without lose the cristalinity and phase purity. For this study, mordenite zeolite was synthetized with the following gel composition: 1Al2O3: 30SiO2: 6Na2O: 780H2O. The method used for the synthesis was sol-gel technique and the heat sources were both hidrothermal and microwave heating. The synthetized material was characterized by X-rays diffraction (XRD), scanning electron microscopy (SEM), High resolution transmission eléctron microscopy (HRTEM), Zeta potential, BET and Phase contrast microscopy. Thromboelastography (TEG) test in vitro was employed to determine the clotting efficiency of the made zeolite when it is in contact with blood. X-Rays diffraction patterns showed that synthesis employing conventional heating took 4 days to yield mordenite zeolite whereas employing microwave heating this synthesis time was decreased to 5 hours. The TEG profile and clotting parameters revealed that without the addition of zeolites, human blood begins to clot at about 9,8 minutes. Adding zeolites to the human blood, regardless of heating source employed, has decreased the clotting time to 3,8 minutes. Elastic properties of the formed clots by using mordenite zeolite as hemostatic agents and thrombin generation were also improved.
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Palavras-chave
Biofísica, Micro-ondas, Mordenita, Coagulantes