Nanoestruturas de óxido de grafeno magnético: modificação e funcionalização de superfície para terapia fotodinâmica e fototérmica
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Data
2017-02-09
Autores
Paiva, Juliana Moreno de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As terapias fotodinâmica e fototérmica vêm sendo desenvolvidas de forma a oferecer melhores e mais baratas alternativas no tratamento de câncer. Os principais desafios na utilização destas técnicas estão na obtenção de novos materiais fototérmicos e fotosensibilizadores que absorvam no mesmo comprimento de onda. Neste contexto, este trabalho desenvolveu um material com este potencial. Para isso foi escolhido como base o óxido de grafeno devido suas propriedades hidrofílica e atóxica, boa estabilidade térmica, capacidade de absorção de luz e possibilidade de funcionalização. Nanopartículas de óxido de ferro magnéticas, floresceína o-metacrilato e o Verteporfin foram ligados em sua superfície trazendo novas características como a possibilidade do uso como agente de contraste no diagnóstico por ressonância magnética nuclear e terapia fotodinâmica. Para isso, estratégia de síntese foi feita em quatro etapas: síntese do óxido de grafeno, óxido de grafeno magnético, óxido de grafeno magnético fluorescente e óxido de grafeno magnético fluorescente com fotossenssibilizador. Na primeira etapa empregou-se o método de Hummers modificado para obtenção do óxido de grafeno pela oxidação e esfoliação do grafite. Em seguida, nanopartículas de óxido de ferro magnético foram imobilizadas em sua superfície pelo método de coprecipitação simples. A propriedade de fluorescência foi então inserida pela ancoragem da fluoresceína o-metacrilato juntamente com o ácido acrílico (AA), persulfato de amônio e bissulfito de sódio. Por fim, o óxido de grafeno foi funcionalizado com o fotossenssibilizador Verteporfin por uma reação de transesterificação. A fim de verificar o caráter físico-químico e estrutural dos intermediários e produtos finais de cada etapa foram utilizadas técnicas de caracterização, como microscopia eletrônica de varredura de alta resolução (FEG-MEV), difratometria de raios X (DRX), espectroscopia RAMAN, espectroscopia na região do ultravioleta/visível (UV-Vis), espectroscopia na região do infravermelho com transformada de Fourier (FTIR), espectroscopia de fluorescência, potencial zeta e espalhamento dinâmico de luz (DLS). A partir dos resultados obtidos, verificou-se que o material obtido tem potencial teranóstico multifuncional com propriedades advindas do óxido de grafeno magnético modificado para aplicações nas terapias fototérmicas e fotodinâmicas.
Photodynamic and photothermal therapies have been developed in order to offer better and cheaper alternatives in cancer treatment. The main challenges in the use of these techniques are in obtaining new photothermal and photosensitizers materials that absorb at the same wavelength. In this context, this work has developed a material with this potential. For this, graphene oxide was chosen as the base due to its hydrophilic and nontoxic properties, good thermal stability, light absorbing capacity and possibility of functionalization. Magnetic iron oxide nanoparticles, fluorescein o-methacrylate and Verteporfin were linked on their surface bringing new features such as the possibility of use as a contrast agent in the diagnosis by nuclear magnetic resonance and photodynamic. For this, the synthesis strategy was done in four steps: synthesis of graphene oxide, magnetic graphene oxide, fluorescent magnetic graphene oxide and fluorescent magnetic graphene oxide with photosensitizer. In the first step, the modified Hummers method was used to obtain graphene oxide by the oxidation and exfoliation of graphite. Next, nanoparticles of magnetic iron oxide were immobilized on their surface by the simple co-precipitation method. The fluorescence property was then inserted by fluorescein o-methacrylate anchoring along with acrylic acid (AA), ammonium persulfate and sodium bisulfite. Finally, the graphene oxide was functionalized with the Verteporfin photosensitizer by a transesterification reaction. In order to verify the physical-chemical and structural character of the intermediates and final products of each step, characterization techniques were used, such as high-resolution scanning electron microscopy (SEM), X-ray diffractometry (XRD), RAMAN spectroscopy, Ultraviolet/visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy, zeta potential and dynamic light scattering (DLS). From the obtained results, it was verified that the material obtained has a multifunctional thermostatic potential with properties derived from modified magnetic graphene oxide for photothermal and photodynamic therapies.
Photodynamic and photothermal therapies have been developed in order to offer better and cheaper alternatives in cancer treatment. The main challenges in the use of these techniques are in obtaining new photothermal and photosensitizers materials that absorb at the same wavelength. In this context, this work has developed a material with this potential. For this, graphene oxide was chosen as the base due to its hydrophilic and nontoxic properties, good thermal stability, light absorbing capacity and possibility of functionalization. Magnetic iron oxide nanoparticles, fluorescein o-methacrylate and Verteporfin were linked on their surface bringing new features such as the possibility of use as a contrast agent in the diagnosis by nuclear magnetic resonance and photodynamic. For this, the synthesis strategy was done in four steps: synthesis of graphene oxide, magnetic graphene oxide, fluorescent magnetic graphene oxide and fluorescent magnetic graphene oxide with photosensitizer. In the first step, the modified Hummers method was used to obtain graphene oxide by the oxidation and exfoliation of graphite. Next, nanoparticles of magnetic iron oxide were immobilized on their surface by the simple co-precipitation method. The fluorescence property was then inserted by fluorescein o-methacrylate anchoring along with acrylic acid (AA), ammonium persulfate and sodium bisulfite. Finally, the graphene oxide was functionalized with the Verteporfin photosensitizer by a transesterification reaction. In order to verify the physical-chemical and structural character of the intermediates and final products of each step, characterization techniques were used, such as high-resolution scanning electron microscopy (SEM), X-ray diffractometry (XRD), RAMAN spectroscopy, Ultraviolet/visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy, zeta potential and dynamic light scattering (DLS). From the obtained results, it was verified that the material obtained has a multifunctional thermostatic potential with properties derived from modified magnetic graphene oxide for photothermal and photodynamic therapies.
Descrição
Palavras-chave
Óxido de grafeno, Tratamento fototérmico, Tratamento fotodinâmico, Câncer, Teranóstico, Graphene oxide, Photothermal treatment, Photodinamic treatment, Cancer, Teranostic