TATIANA SANTANA BALOGH
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Tese IPEN-doc 30752 Comparative study of different methodologies for synthesis of nanogels as potential drug carriers2023 - BALOGH, TATIANA S.Nanogels are defined as nanometer-scale polymeric gels, considered innovative and promising nanomaterials for drug delivery systems. This joint Polish-Brazilian work aimed to contribute to the development of the area of production of nanogels by means of ionizing radiation, investigating different synthesis methodologies, namely gamma and electron beam-induced irradiation. Original and innovative method of nanogel synthesis via ultraviolet-induced radiation has been proposed in an unprecedented manner and successfully developed. Additionally, the possibility of conjugation of selected nanogels with technetium-99m (99mTc) has been investigated as a possible theranostic agent. In case of ionizing radiation-supported techniques influence of solution concentration, type of gas saturation and dose on physicochemical properties of irradiation products have been analysed. In the UV methodology different ratios of the number of OH radicals available in the system per number of monomeric units were evaluated with and without argon saturation. All samples were characterized in relation to weight-average molecular weight (Mw), Z-average radius of gyration (Rg), hydrodynamic radius (Rh) and second virial coefficient using DLS and SLS techniques. The ratio of the radius of gyration to the hydrodynamic radius (Rg/Rh), the polymer coil density (ρcoil), morphology by SEM and TEM, and topography by AFM were determined. Radiolabelling with technetium-99m was carried out both via direct and indirect methodology, in addition to purification and radiochemical stability tests. PVP K-90-based nanogels of different crosslink densities were successfully obtained in all proposed methods. It has been found that the use of nitrous oxide promoted higher number of hydroxyl radicals, favouring the formation of intramolecular crosslinking. The increase in the amount of OH radicals available in the medium (both by increase of the ionizing radiation dose and concentration of OH radical precursor (H2O2)) provided higher influence of intramolecular crosslinking. It was possible to radiolabel and purify PVP K-90 nanogels produced by e-beam and gamma irradiation with technetium-99m through [99mTc(CO)3(H2O)3]+.Artigo IPEN-doc 28864 Synthesis of poly(N-vinyl pyrrolidone) (PVP) nanogels by gamma irradiation using different saturation atmospheres2022 - BALOGH, TATIANA S.; BONTURIM, EVERTON; VIEIRA, LUCAS D.; LUGAO, ADEMAR B.; KADLUBOWSKI, SLAWOMIRNanogels are internally crosslinked particles of nanometric size used in various fields e.g. as such as carriers in drug delivery systems. They can be produced using ionizing radiation in dilute aqueous solutions. This method is carried out in a pure polymer-solvent system, avoiding the addition of any additives such as monomers, surfactants, catalysts and crosslinking agents and no further purification step is necessary. Poly(N-vinyl pyrrolidone) (PVP K-90) nanogels were prepared by gamma irradiation in an aqueous solution. The samples were prepared in triplicate in multipurpose cobalt-60 gamma irradiator using 1, 10, 25 and 100 mM PVP solutions. Samples were irradiated in argon and nitrous oxide conditions with doses from 1 kGy up to 25 kGy with 10 kGy/h dose rate. The mean particle size (Rh) was determined by Dynamic Light Scattering (DLS) and radius of gyration (Rg) and weight-average molecular weight (Mw) by Static Light Scattering (SLS). These samples were morphologically characterized using Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). Samples prepared with 100 mM PVP K-90 solution formed macroscopic gels, in the samples obtained with 25 mM PVP K-90 solution there was a prevalence of intermolecular crosslinking. On the other hand, in the samples generated with 10 mM PVP K-90 solution, there was a predominance of intramolecular crosslinking demonstrated in the tendency to: decrease in the radius of gyration (Rg), in the constancy of the weight-average molecular weight (Mw), in the increase in polymer coil density (ρcoil), in the Rg/Rh ratio (shape factor) around 1.0 indicating homogenous, internally cross-linked spheres, in the high relief spherical structures observed in the AFM images and in the spherical particles with high contrast observed in the TEM images. The saturation of the samples with nitrous oxide doubled formation of hydroxyl radicals, favoring the generation of polymeric radicals. Higher average number of radicals in each macromolecule contributed to the higher number of intramolecular crosslinks.Artigo IPEN-doc 27582 An updated review of macro, micro, and nanostructured hydrogels for biomedical and pharmaceutical applications2020 - LIMA, CAROLINE S.A. de; BALOGH, TATIANA S.; VARCA, JUSTINE P.R.O.; VARCA, GUSTAVO H.C.; LUGAO, ADEMAR B.; CAMACHO-CRUZ, LUIS A.; BUCIO, EMILIO; KADLUBOWSKI, SLAWOMIR S.Hydrogels are materials with wide applications in several fields, including the biomedical and pharmaceutical industries. Their properties such as the capacity of absorbing great amounts of aqueous solutions without losing shape and mechanical properties, as well as loading drugs of different nature, including hydrophobic ones and biomolecules, give an idea of their versatility and promising demand. As they have been explored in a great number of studies for years, many routes of synthesis have been developed, especially for chemical/permanent hydrogels. In the same way, stimuli-responsive hydrogels, also known as intelligent materials, have been explored too, enhancing the regulation of properties such as targeting and drug release. By controlling the particle size, hydrogel on the micro- and nanoscale have been studied likewise and have increased, even more, the possibilities for applications of the so-called XXI century materials. In this paper, we aimed to produce an overview of the recent studies concerning methods of synthesis, biomedical, and pharmaceutical applications of macro-, micro, and nanogels.