Encapsulated Natural And Synthetic Photosensitizers By Silica Nanoparticles For Photodynamic Therapy
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Date
2015-05
Authors
MAKHADMEH, GHASEB NASER
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Abstract
Photodynamic therapy is a unique new cancer treatment that uses dye (photosensitizer) which interacts with light. The main problem of using photosensitizers is the difficulty of the dye travelling in biological systems and the dye may be rapidly cleared by the reticulo- endothelial system of the body. One of the aims of this thesis is test the effectiveness of silica nanoparticles used as a delivery agent in photodynamic therapy by encapsulating the photosensitizers molecules. Another aim is to test the effectiveness of the encapsulation of natural and chemical photosensitizers by measuring their efficacy in photodynamic therapy on special targets such as red blood cells, cancer cells, and artificial tissue. The results obtained showed that it is possible for silica nanoparticles to encapsulate many types of photosensitizers. General observation showed that the loaded number of photosensitizers molecules in the silica nanoparticles increased with the increase in the photosensitizers concentration, but limited by the silica nanoparticles size, probably at its elasticity limit (i.e diameter expansion). The photodynamic application on the red blood cells showed that the encapsulated photosensitizers have higher efficacy. For concentration efficacy (more required concentration means less efficacy), encapsulated cichorium pumilum (as a natural photosensitizer), methylene blue and protoporphyrin IX (as a synthetic photosensitizers) have higher efficacy than naked cichorium pumilum, methylene blue and protoporphyrin IX approximately by 46, 98 and 78%, respectively. And also for exposure time efficacy, encapsulated cichorium pumilum, methylene blue and protoporphyrin IX have higher
efficacy than naked cichorium pumilum, methylene blue and protoporphyrin IX approximately by 98, 86 and 48%, respectively. Another photodynamic applications such as on the osteosarcoma cells and artificial tissue showed that the encapsulated photosensitizers have higher efficacy than naked photosensitizers by concentration and exposure time. The reasons for the higher efficacy of encapsulated PS are that the encapsulated PS molecules population are kept secured together by SiNPs; thus, cause high absorbance of energy light and production of singlet oxygen to be increased. However, compared to the naked PS, the PS molecules were spread throughout in the solution and its interaction with the light was slow and dispersed; thus, singlet oxygen production was less than the amount that was produced by encapsulated PS. From the results, the encapsulation by silica nanoparticles, as a delivery agent, increased the photosensitizers efficacy, as a photodynamic therapy factor and the naked photosensitizer has less efficacy compared to encapsulated photosensitizers for all photodynamic applications that used in this work.
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Encapsulated Natural And Synthetic Photosensitizers , By Silica Nanoparticles For Photodynamic Therapy