Síntese verde de nanopartículas de ouro e aplicações no diagnóstico e terapia da aterosclerose

• Ano de defesa: 2015
• Autor(a) principal: Gonçalves, Karina de Oliveira [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: Gold nanoparticles; Protoporphyrin IX; Atherosclerosis; Teranóstica; Fluorescence; Nanopartículas de ouro; Protoporfirina IX; Aterosclerose; Fluorescência
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=2797587; http://repositorio.unifesp.br/handle/11600/46893

Atherosclerosis is a chronic degenerative disease that affects medium and large caliber arteries, and is characterized by lesions with plaque or atheroma. It is the primary cause of heart diseases and strokes, which are the global leading causes of death by disease. Atheromatous plaques exhibit an accumulation of protoporphyrin IX, or PPIX, which is transferred to the blood and feces. PPIX is a potential marker for atherosclerosis that may facilitate minimally invasive and cost effective diagnostic method. This work purpose is to associate a precursor of the PPIX, the aminolevulinic acid, to gold nanoparticles (ALA:AuNPs), to act as a photosensitizing agent for photothermic, phothodynamic and sonodynamic therapies, allowing the destruction of plaques. ALA:AuNPs was synthesized mixing 5-ALA with Tetrachloroauric(III) acid in milli-Q water solution followed by photoreduction with light from a Xenon lamp. The best synthesis conditions, such as optimal illumination time, more appropriate pH, most effective temperature and better stoichiometry were obtained from measurements of UV/Vis optical absorption, electron microscopy and zeta potential. Male New Zeland rabbits were used to monitor the atherosclerosis staging for 60 days. The animals were divided into 5 groups with 4 animals in the control group and 3 aminals for the other groups: control group (CG) where animals received normal diet, and control group with 5-ALA (CGALA); Experimental group (EG), in which the animals received a high calorie diet with 1% cholesterol; Experimental group with 5-ALA (EGALA) and Experimental Group with ALA:AuNPs (EGALA:Au). Changes in the animal?s arteries throughout the study were analyzed by optical microscopy techniques. Blood samples and animal feces, and extracted PPIX in different disease stages (early, 30 and 60 days) were analyzed. Measurements of the emission intensity of PPIX extracted from both the feces and blood of animals in the region between 575 and 725 nm were done. The results with blood and feces, showed an increase of PPIX to the experimental groups GEALA and GEALA:Au, which indicates indicated that the ALA:AuNPs can be used as a theranostic agent of atherosclerosis.