Título:	Nanodispersões de poli(pivalato de vinila) com propriedades magnéticas visando aplicações biomédicas : síntese e avaliação in vitro de sua citotoxicidade em células cancerígenas
Autor(es):	Silvério Neto, Weslany
Orientador(es):	Silva, Fabricio Machado
Coorientador(es):	Valadares, Leonardo Fonseca Souza Júnior, Fernando Gomes de
Assunto:	Polimerização em miniemulsão Nanopartículas magnéticas Nanocompósitos Hipertermia Citotoxicidade
Data de publicação:	19-Jan-2024
Data de defesa:	25-Jan-2019
Referência:	SILVÉRIO NETO, Weslany. Nanodispersões de poli(pivalato de vinila) com propriedades magnéticas visando aplicações biomédicas: síntese e avaliação in vitro de sua citotoxicidade em células cancerígenas. 2019. 119 f., il. Tese (Doutorado em Química) — Universidade de Brasília, Brasília, 2019.
Abstract:	The development of polymer nanomaterials, which combine properties of thermoplastic polymers and superparamagnetic nanoparticles, presents great potential for biomedical applications, such as the treatment of tumors through intravascular embolization and hyperthermia procedure. Therefore, this work aims at the development of a new embolic agent formed by magnetic nanoparticles of iron oxide (Fe3O4) coated with chemically modified oleic acid and which were uniformly dispersed in spherical nanoparticles of poly(vinyl pivalate). For encapsulating the magnetic material in the polymer matrix, nanoparticles were coated with modified oleic acid, obtained by insertion of a reactive functional group, acrylic acid in the oleic acid chain, using the epoxidation process followed by the acrylation reaction. The polymeric fluid was synthesized through miniemulsion polymerization process. The nanocomposite was obtained in situ through the polyaddition reaction of vinyl pivalate in the presence of magnetic nanoparticles coated with acrylated oleic acid via miniemulsion. The synthesized samples were characterized by infrared absorption vibration spectroscopy, nuclear magnetic resonance (1H-NMR), thermogravimetric analysis, dynamic light scattering, differential thermal analysis, differential scanning calorimetry, X-ray diffraction, transmission electron microscopy, Mössbauer spectroscopy, Raman spectroscopy, magnetization measurements and gel permeation chromatography. The cytotoxicity of poly(vinyl pivalate) and nanocomposites was evaluated in vitro in B16F10 melanoma cancer cells, murine mammary adenocarcinoma (4T1-luciferase), NIH-3T3 fibroblast cells and human keratinocytes (HaCat). The results showed that the coated nanoparticles showed thermal stability, good dispersibility with uniform average size of 9.5 nm, saturation magnetization of 61.2 emug-1 and superparamagnetic behavior. The results of poly(vinyl pivalate) showed average conversions of 82% and mass-average molar masses ranging from 335 to 840 kgmol-1. Polymerization reactions carried out with water-soluble initiator, potassium persulphate, presented a decrease in the average diameter during the polymerization process due to the homogeneous nucleation that occurred simultaneously to nucleation of the new droplets. The average diameters of the lattices obtained with the use of the organosoluble initiator, benzoyl peroxide, remained practically unchanged until the end of the process. In the formation of the nanocomposites, the use of the polymerization process in miniemulsion allowed the formation of stable colloidal dispersions, with effective control over particle size and morphology. The magnetopolimeric fluids formed containing 5.0 to 20.0 wt% of OM-AOA exhibited a mean diameter of approximately 180 nm, spherical morphology and preserved the superparamagnetic behavior. Cell viability tests demonstrated that nanocomposites as well as poly (vinyl pivalate) nanoparticles did not present representative cytotoxicity to tumor and non-tumor cells at the concentrations studied. The physico-chemical properties and non-cytotoxicity suggest the potential of magnetopolimeric fluids as an embolic agent for selective and complete obstruction of blood vessels of different sizes and capacity for treatment by hyperthermia.
Unidade Acadêmica:	Instituto de Química (IQ)
Informações adicionais:	Tese (doutorado) — Universidade de Brasília, Instituto de Química, Programa de Pós-Graduação em Química, 2019.
Programa de pós-graduação:	Programa de Pós-Graduação em Química
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.unb.br, www.ibict.br, www.ndltd.org sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra supracitada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
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