Aplicação da sílica mesoporosa SBA-15 e SBA-16 para adsorção e liberação controlada do fármaco curcumina: propriedades ópticas, fotofísicas e texturais
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Data
2022-01-07
Autores
Chebat, Lucas Garcia
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Universidade Estadual Paulista (Unesp)
Resumo
As sílicas mesoporosas tipo SBA-15 e SBA-16 possuem uma grande área de superficial e
uma rede de poros ordenados com estrutura hexagonal em escala nanométrica, que torna esses
materiais excelentes adsorvedores de uma variedade de moléculas. Essas sílicas são inertes do
ponto de vista ambiental, sendo bem tolerado por seres vivos podendo ser usadas como carreadora
e/ou para liberação de fármacos adsorvidos em sua porosidade (drug delivery). A curcumina é um
componente ativo do açafrão-da-Índia, de baixa toxicidade que apresenta propriedades
bactericidas e fungicidas, e cujo efeito fotodinâmico vem sendo estudado por seu potencial para
exterminar larvas de mosquito Aedes aegypti, transmissor da dengue. A molécula de curcumina é
fotossensível, podendo sofrer fotodegradação e diminuição de sua eficácia quando exposta a luz
do dia. Um dos objetivos deste trabalho é incorporar a molécula de curcumina nos poros da sílica
SBA-15 e da SBA-16 para estudar o potencial de adsorção da curcumina na porosidade dessas
sílicas mesoporosas. Devido à fotossensibilidade da curcumina, é de suma importância o estudo
das propriedades ópticas (absorção e emissão UV-VIS) da curcumina adsorvida nas sílicas SBA 15 e na SBA-16. Do ponto de vista de caracterização da fotoestabilidade dos materiais foi estudada
a fotodegradação de amostras de curcumina adsorvida em ambas as sílicas, quando expostas à luz
visível. Análises de superfície (BET) realizadas nas sílicas SBA-15 e SBA-16 puras e dopadas
com curcumina revelaram importantes parâmetros sobre a incorporação da curcumina na
porosidade destas sílicas mesoporosas, como a formação de duas classes de poros com tamanho
de poros diferentes indicando incorporação de curcumina nas paredes internas dos poros, e os
resultados também mostraram que há incorporação de curcumina na área superficial externa de
ambas amostras, sendo maior na superfície externa da amostra SBA15 comparada a SBA16.
Mesoporous silicas type SBA-15 and SBA-16 have a large surface area and an ordered pore network with a hexagonal structure at the nanometer scale, which makes these materials excellent adsorbers of a variety of molecules. These silicas are inert from the environmental point of view, being well tolerated by living beings and can be used as a carrier and/or to release drugs adsorbed in their porosity (drug delivery). Curcumin is an active component of turmeric Indian Saffron, with low toxicity that has bactericidal and fungicidal properties, and whose photodynamic effect has been studied for its potential to kill Aedes aegypti mosquito larvae, which transmits dengue. The curcumin molecule is photosensitive and may undergo photodegradation and decrease its effectiveness when exposed to daylight. One of the objectives of this work is to incorporate the curcumin molecule into the pores of silica SBA-15 and SBA-16 to study the adsorption potential of curcumin on the porosity of these mesoporous silicas. Due to the photosensitivity of curcumin, it is extremely important to study the optical properties (UV-VIS absorption and emission) of curcumin adsorbed on SBA-15 and SBA-16 silicas. From the point of view of characterizing the photostability of the materials, the photodegradation of curcumin samples adsorbed on both mesoporous silicas, when exposed to visible light, was studied. Surface analysis (BET) performed on pure and doped SBA-15 and SBA-16 silicas with curcumin revealed important parameters on the incorporation of curcumin in the porosity of these mesoporous silicas, such as the formation of two classes of pores with different pore sizes indicating incorporation of curcumin in the internal pore walls, and the results also showed that there is incorporation of curcumin in the external surface area of both samples, being higher on the external surface of the SBA15 sample compared to SBA16.
Mesoporous silicas type SBA-15 and SBA-16 have a large surface area and an ordered pore network with a hexagonal structure at the nanometer scale, which makes these materials excellent adsorbers of a variety of molecules. These silicas are inert from the environmental point of view, being well tolerated by living beings and can be used as a carrier and/or to release drugs adsorbed in their porosity (drug delivery). Curcumin is an active component of turmeric Indian Saffron, with low toxicity that has bactericidal and fungicidal properties, and whose photodynamic effect has been studied for its potential to kill Aedes aegypti mosquito larvae, which transmits dengue. The curcumin molecule is photosensitive and may undergo photodegradation and decrease its effectiveness when exposed to daylight. One of the objectives of this work is to incorporate the curcumin molecule into the pores of silica SBA-15 and SBA-16 to study the adsorption potential of curcumin on the porosity of these mesoporous silicas. Due to the photosensitivity of curcumin, it is extremely important to study the optical properties (UV-VIS absorption and emission) of curcumin adsorbed on SBA-15 and SBA-16 silicas. From the point of view of characterizing the photostability of the materials, the photodegradation of curcumin samples adsorbed on both mesoporous silicas, when exposed to visible light, was studied. Surface analysis (BET) performed on pure and doped SBA-15 and SBA-16 silicas with curcumin revealed important parameters on the incorporation of curcumin in the porosity of these mesoporous silicas, such as the formation of two classes of pores with different pore sizes indicating incorporation of curcumin in the internal pore walls, and the results also showed that there is incorporation of curcumin in the external surface area of both samples, being higher on the external surface of the SBA15 sample compared to SBA16.
Descrição
Palavras-chave
Açafrão-da-terra, Física, Curcumina, Espectroscopia de emissão, Fotodegradação, Sílica mesoporosa, SBA-15, SBA-16, Propriedades ópticas, Análises de superfície, Mesoporous silica, Curcumin, Optical properties, Surface analysis