JAQUELINE JAMARA SOUZA SOARES
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Artigo IPEN-doc 26514 The effect of gamma radiation on the structure of graphene oxide and graphene oxide functionalized with amino-PEG2019 - SOARES, J.J.S.; JACOVONE, R.M.S.; SANTOS, P.S.; ZAIM, M.H.; FARIA, D.L.A.; SAKATA, S.K.Covalent functionalization of graphene oxide (GO) with polyethylene glycol (PEG) has been widely used in drug delivery systems. This nanocomposite exhibits excellent stability in the presence of high concentrations of salts and proteins and shows low toxicity compared to its raw form. However, it must be sterilized prior to use in medical devices, and for this purpose, the gamma irradiation shows a promising option. Sterilization by ionizing energy through gamma rays, generated by Cobalt-60 self-disintegration, consists in exposing the materials to short electromagnetic waves. The irradiation process provides substantial advantages when compared to thermal and chemical processes, such as, more precise control of the process, lower energy consumption, and less environmental pollution. In this work the effects of gamma radiation on GO and GO functionalized with amino-PEG (GO-PEG-NH2) irradiated with doses (15, 25, 35 and 50 kGy) at rate dose of 7.3 kGy.h-1 were evaluated. The analyses were performed by Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The results showed that gamma radiation up to 50 kGy did not cause any defects on the nanomaterials.Dissertação IPEN-doc 25678 Utilização do nanocompósito à base de óxido de grafeno no pericárdio bovino empregado em dispositivos cardiovasculares2019 - SOARES, JAQUELINE J.S.A doença cardíaca valvar é um problema clínico que está presente em todos os países independente do nível de desenvolvimento econômico. Anualmente são realizadas mais de 275.000 cirurgias para substituição da válvula aórtica em todo o mundo e a estimativa é que esse número triplique até 2050. Dentre as próteses utilizadas destaca-se a bioprótese, que apesar de apresentar uma rejeição menor que a prótese mecânica, a sua durabilidade é reduzida em virtude de sua calcificação e posterior deterioração. A fim de aumentar a durabilidade da prótese confeccionada a partir do pericárdio bovino, neste estudo, foi incorporado o óxido de grafeno funcionalizado com amino-polietilenoglicol 4.000 Mn (OG-PEG-NH2 4.000 Mn) e 6.000 Mn (OG-PEG-NH2 6.000 Mn) ao biomaterial. A incorporação do óxido de grafeno funcionalizado ao pericárdio bovino foi realizada, após sua esterilização com radiação gama, de duas formas distintas: por adsorção física e por reação química. Os resultados demonstraram que houve a incorporação do OG-PEG-NH2 4.000 Mn, verificado pelo aumento dos parâmetros de ensaio de resistência analisados, como por exemplo, a resistência à deformação plástica permanente e também a carga máxima suportada. Em relação ao OG-PEG-NH2 6.000 Mn houve uma melhora na biocompatibilidade do nanomaterial, diminuindo a sua citotoxicidade. Sendo assim, pode-se concluir que o OG-PEG-NH2 4.000 Mn possui o potencial para melhorar a resistência mecânica e consequentemente aumentar a durabilidade do biomaterial.Resumo IPEN-doc 25330 Synthesis and characterization of graphene oxide/nickel nanoparticles using nanoparticle tracking analysis2018 - JACOVONE, R.M.S.; SOARES, J.J.S.; SAKATA, S.K.One of the graphene based compounds that has giving attention is graphene oxide (GO). This nanomaterial has oxygenated groups on its surface, which provide hydrophilicity and allow its exfoliation in several polar solvents. Moreover, these reactive sites can be further functionalized, yielding nanocomposites with many applications in electrochemistry and biomaterials fields. The objective of this study is to synthesize nickel / graphene oxide (GO-Ni) nanocomposite using electron beam in water /alcohol solution without stabilizers and to characterize GO and GO-Ni by Nanoparticle Tracking Analysis (NTA). The Nanoparticle Tracking Analysis utilizes the properties of both light scattering and Brownian motion in order to obtain the particle size distribution and to measure the diffusion coefficient. From the Stokes-Einstein equation it was possible to obtain the hydrodynamic diameter of the nanomaterials. The NTA result showed that GO and GO-Ni showed respectively 47 nm and 55nm. Both showed a low polydispersity index, indicating the homogeneity of the size distribution and the formation of a monodisperse system. The results showed that it is possible to obtain nanoparticles of graphene oxide incorporated with nickels smaller than 60 nm and with good distribution without the use of stabilizers.Resumo IPEN-doc 25329 Synthesis and characterization of magnetic graphene oxide nanocomposites2018 - TOMINAGA, F.K.; SAKATA, S.K.; SOARES, J.J.S.; JACOVONE, R.M.S.Graphene oxide (GO) is a unique material that can be described as a single monomolecular layer of graphite containing various oxygen functionalities such as epoxide, carbonyl, carboxyl and hydroxyl groups. Chemical modifications at the surface of the graphene oxide through the incorporation of magnetite can provide magnetic properties to these nanomaterials. This work aims to synthesize and characterize graphene oxide/magnetite (GO/M) nanocomposites, evaluating the different proportions of incorporated magnetite. The synthesis of graphene oxide/magnetite nanocomposites was performed by co-precipitation of iron salts on the graphene oxide (GO) particles in alkaline medium. The characterization of the nanocomposites was performed by thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), X-ray diffraction (XRD), nanoparticle tracking analysis (NTA) and scanning electron microscopy (SEM). The thermogravimetric results showed the incorporation of approximately 20, 50, 70 and 80% of magnetite to the graphene oxide. Regarding the hydrodynamic size, for the magnetite, mode values of 31.3 ± 1.3 nm were determined, whereas for the GO/M, the mode values of size ranged from 72.8 to 194 nm. The results of XRD and FTIR showed the respective characteristic diffraction and absorption peaks only for graphene oxide, magnetite and GO/M(20%). It was not observed characteristic peaks for the other samples of graphene oxide that have higher loads of magnetite incorporated.Resumo IPEN-doc 25305 The effect of gamma radiation on the stability of aqueous dispersions of graphene oxide and graphene oxide functionalized with amino-peg2018 - SOARES, J.J.S.; SANTOS, P.S.; ZAIM, M.H.; SAKATA, S.K.Nanocomposites based on graphene have been prominent in the field of biomedicine due to the biocompatibility with the physiological medium and the possibility of being functionalized by a series of biocompatible polymers, such as chitosan, polyethylene glycol, poly (caprolactone), among others. However, there is a need for sterilization of these nanomaterials in the medical field and gamma irradiation is a promising option. In the present work graphene oxide (GO), produced by the modified Hummers method, was functionalized with amino-PEG (GO-PEG-NH2) through the amidation process. The objective of this study was to evaluate the aqueous dispersions stability of these nanomaterials before and after gamma radiation (Cobalt 60) at a dose of 25 kGy. Dynamics light scattering (DLS) was used to determine the zeta potential. The results showed no significant differences between the zeta potentials of the non-irradiated and irradiated graphene oxide. The dispersion of the functionalized graphene oxide showed to be stable and the irradiated unstable.