Derivados de poli(L-lisina) com fosforilcolina para transferência gênica não-viral

• Ano de defesa: 2014
• Autor(a) principal: Semensato, Juliana [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Físico-química; Terapia gênica; Polilisina; Vetores genéticos; Nanopartículas; Fosforilcolina; Gene therapy
• Link de acesso: http://hdl.handle.net/11449/111019

Gene therapy based on non-viral vectors, such as those that utilize polymerics systems, is a promising treatment for diseases that arise due some genetic disorder. However the challenge of using this technique is the transfer of the genetic material and most of the efforts have focused on the development of effective vectors to efficiently deliver the DNA into the cells. In this work, the main purpose was to synthesize PLL derivatives containing increasing proportions of the group phosphorylcholine (PC), aiming to improve the PLL properties as a non viral vector. The derivatives were characterized by ¹H NMR, FTIR-ATR and GPC techniques. The degree of substitution was determined by ¹H NMR and potentiometry. The buffering capacity was evaluated and showed the grafting with PC groups increased the buffering capacity, which may improve the transfection efficiency. The interaction between PLL and PLL-PC derivatives and the plasmid VR 1412, was studied at two pH values (pH 5.0 and 7.4) by fluorescence, agarose gel electrophoresis, dynamic light scattering and zeta potential techniques. The results showed that all derivatives were able to form polyplexes depending on the degree of substitution, pH and the charge ratio (N/P, the ratio of amino groups to phosphate groups from the pDNA). Nanoparticles prepared using the coacervation process showed sizes varying from 150 to 300 nm at pH 5.0 and from 350 to 700 nm at pH 7.4. The particles exhibited positives surface charges (~ +25 mV at pH 5.0 and ~ +10 mV at pH 7.4) an important property for promoting the internalization process by endocytosis. Cell viability using the MTS colorimetric assay showed that increasing proportions of PC groups can reduce the cytotoxicity of nanoparticles, and IC50 values for the sinthesized polymers were graphically determined. The in vitro transfection efficiencies were shown to depend on the degree of substitution and N/P ratio and all the derivatives showed ...