Browsing by Author "Brito, Ana Carolina Ferreira de"

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    Association of electroanalytical and spectrophotometric methods to evaluate the antioxidant activity of isobenzofuranone in primary cultures of hippocampal neurons.
    (2020) Teixeira, Aniely dos Reis; Teixeira, Róbson Ricardo; Ribeiro, Iara Mariana Léllis; Pereira, Wagner Luiz; Manhabosco, Taíse Matte; Brito, Ana Carolina Ferreira de; Oliveira, Laser Antônio Machado de; Nogueira, Katiane de Oliveira Pinto Coelho
    The isobenzofuran-1(3H)-ones (phthalides) exhibit various biological activities, including antioxidant activity on reactive oxygen species (ROS). An excess of ROS that cannot be naturally contained by cellular enzymatic systems is called redox imbalance, which damage cell membranes, proteins, and DNA, thereby possibly triggering neuronal death in several neurodegenerative diseases. Considering our ongoing efforts to find useful compounds to control redox imbalance, herein we evaluated the antioxidant activity of two phtalides (compounds 3 and 4), using primary cultures of hippocampal neurons. Spectrophotometric assays showed that compound 3 significantly reduced (p ≤ 0.05) ROS levels and lipid peroxidation compared to the control treatment, while compound 4 was unable at any of the tested concentrations. Despite their structural similarity, these compounds behave differently in the intracellular environment, which was reliably corroborated by the determination of oxidation potentials via cyclic voltammetry. It was demonstrated that compound 3 presents a lower oxidation potential. The combination of the mentioned methods allowed us to find a strong correlation between the chemical structure of compounds and their biological effects. Taking together, the results indicate that compound 3 presents desirable characteristics to act as a candidate pharmacological agent for use in the prevention and treatment of neurodegenerative diseases.
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    Improved bioceramic coatings reinforced by nanostructured talc.
    (2022) Batista, Ana Bárbara; Silva, Michael Stanley da; Brito, Ana Carolina Ferreira de; Vasconcellos, Rebecca; Munk, Michele; Bueno, Mário José; Godoy, Geralda Cristina Durães de; Alvarenga, Érika Lorena Fonseca Costa de; Vasconcelos, Cláudia Karina Barbosa de; Righi, Ariete; Sousa, Edésia Martins Barros de; Oliveira, Alan Barros de; Batista, Ronaldo Junio Campos; Soares, Jaqueline dos Santos; Neves, Bernardo Ruegger Almeida; Barboza, Ana Paula Moreira; Manhabosco, Taíse Matte
    Nano-talc was successfully incorporated in the hydroxyapatite matrix via pulsed electrodeposition after being obtained using an eco-friendly liquid-phase exfoliation process. Scanning electron microscopy, atomic force microscopy, X-ray spectroscopy, Raman spectroscopy, corrosion and wear resistance, and cytocompatibility tests were used to characterize the biocomposite ceramics. Talc significantly improves the nanomechanical and wear properties of bioceramics (i.e., higher stiffness, reduced friction coefficient, and lower wear damage) as well as corrosion resistance. Talc does not induce cytotoxic activity in in vitro cells and may induce bone maturation as per biocompatibility tests.
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    Labeling PLA-PEG nanocarriers with IR780 : physical entrapment versus covalent attachment to polylactide.
    (2020) Machado, Marina Guimarães Carvalho; Lana, Gwenaelle Elza Nathalie Pound; Oliveira, Maria Alice de; Lanna, Elisa Gomes; Fialho, Márcia Célia Pacheco; Brito, Ana Carolina Ferreira de; Barboza, Ana Paula Moreira; Soares, Rodrigo Dian de Oliveira Aguiar; Mosqueira, Vanessa Carla Furtado
    Near-infrared fluorescent dyes, such as IR780, are promising theranostics, acting as photosensitizers for photodynamic therapy and in vivo tracers in image-guided diagnosis. This work compared the uptake by macrophage-like cells of IR780 either physically associated or covalently attached to poly(D,L-lactide) (PLA) formulated as polymeric nanocapsules (NC) from a blend of PLA homopolymer and PLA-PEG block copolymer. The physicochemical characterization of both NC was conducted using asymmetric flow field-flow fractionation (AF4) analysis with static and dynamic light scattering and atomic force micros copy. The interaction of IR780 with serum proteins was evidenced by AF4 with fluorescence detection and flow cytometry in cell uptake studies. The average diameters of NC were around 120 nm and zeta potentials close to -40 mV for all NC. NC uptake by cells in different media and experimental conditions shows significantly lower fluorescence intensities for IR780 covalently linked to PLA and correspondingly low quantitative uptake. Different mechanisms of internalization were evidenced depending on the IR780 type of association to NC. Serum proteins mediate IR780 interaction with cells in a dose-dependent manner. Our results show that non-covalently linked IR780 was released from NC and accumulated in macrophage cells. Oppositely, IR780 conjugated to PLA provides stable association with NC, and its fluorescence is representative of cell uptake of the nanocarrier itself. This work strongly reinforces the importance of covalent attachment of a fluorescence dye such as IR780 to the nanocarrier to study their interaction with cells in vitro and to obtain reliable tracking in image-guided therapy.
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    PLA-PEG nanospheres decorated with phage display selected peptides as biomarkers for detection of human colorectal adenocarcinoma.
    (2020) Souza, Aline Maria Arlindo de; Borges, William de Castro; Andrade, Milton Hércules Guerra de; Maia, Yara Cristina de Paiva; Goulart Filho, Luiz Ricardo; Lanna, Elisa Gomes; Brito, Ana Carolina Ferreira de; Barboza, Ana Paula Moreira; Mosqueira, Vanessa Carla Furtado; Rúbio, Karina Taciana Santos
    Peptide-mediated targeting to colorectal cancer can increase selectivity and specificity of this cancer diagnosis acting as biomarkers. The present work aimed to select peptides using the phage display technique and associate the peptides with polymeric nanospheres in order to evaluate their cytotoxicity and selectivity during cell interaction with Caco-2 human colon tumor cell line. Two peptides identified by phage display (peptide-1 and peptide-2) were synthesized and exhibited purity higher than 84%. Poly(lactic acid)-block-polyethylene glycol nanospheres were prepared by nanoprecipitation and double emulsion methods in order to load the two peptides. Nanoparticles ranged in size from 114 to 150 nm and peptide encapsulation efficiency varied from 16 to 32%, depending on the methodology. No cytotoxic activity was observed towards Caco-2 tumor cell line, either free or loaded peptides in concentrations up to 3 μM at incubation times of 6 and 24 h, indicating safety as biomarkers. Fluorescein isothiocyanate–labeled peptides allowed evaluating selective interactions with Caco-2 cells, where peptide-1 entrapped in nanospheres showed greater intensity of co-localized cell fluorescence, in comparison to peptide-2. Peptide-1 loaded in nanospheres revealed promising to be investigated in further studies of selectivity with other human colon rectal cells as a potential biomarker.
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    Síntese, caracterização e estudo das propriedades fotofísicas de um novo análogo de isoxazol com potencial de aplicação em dispositivos orgânicos optoeletrônicos.
    (2017) Brito, Ana Carolina Ferreira de; Cazati, Thiago; Taylor, Jason Guy; Cazati, Thiago; Gil, Laurent Frédéric; Valaski, Rogério
    Isoxazóis são conhecidos devido seu potencial em atividades biológicas, mas têm sido inexplorados como intermediários sintéticos para aplicações em ciência dos materiais. Estes compostos heterocíclicos de cinco membros podem compor o núcleo rígido de moléculas capazes de exibir mesofases (caráter cristal-líquido), além de deslocalizarem elétrons em sistemas conjugados. Tais características tornam esta classe de compostos candidatos promissores para aplicação em eletrônica orgânica. O objetivo deste trabalho foi sintetizar um novo análogo de isoxazol luminescente, caracterizá-lo estruturalmente e estudar suas propriedades optoeletrônicas a fim de avaliar seu potencial para aplicação em dispositivos orgânicos. Um novo isoxazol foi sintetizado em quatro etapas sintéticas. O análogo inédito obtido foi o 1,3-bis(3-(2-(octiloxi)fenil) isoxazol-5-il) benzeno (LED 001). A molécula LED 001 em solução apresentou absorção óptica na região do ultravioleta (de 290 nm a 330 nm), com comprimento máximo de absorção centrado em 306 nm. Os coeficientes de absortividade molar () foram de 4056,43 L.mol-1.cm-1 em clorofórmio e de 1362,09 L.mol-1.cm-1 em dimetilformamida; sua eficiência quântica de fluorescência em dimetilformamida (ΦF =0,03) apresentou maior valor que em clorofórmio (ΦF =0,01). O nível de energia do HOMO (do inglês, highest occupied molecular orbital) da LED 001 foi estimado em 5,02 eV. Os valores encontrados para o nível de energia do LUMO (do inglês, lowest unoccupied molecular orbital) e a energia de gap, equivalentes a 1,21 eV e 3,81 eV, respectivamente, tornam a LED 001 um material promissor para utilização em dispositivos optoeletrônicos como modificador de interface, tanto para facilitar a extração/ejeção de cargas.
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    Synthesis, crystal structure, photophysical properties and theoretical studies of a novel bis(phenylisoxazolyl) benzene derivative.
    (2018) Brito, Ana Carolina Ferreira de; Correa, Rodrigo de Souza; Pinto, Antonio A.; Matos, Matheus Josué de Souza; Taylor, Jason Guy; Cazati, Thiago
    Isoxazoles have well established biological activities but, have been underexplored as synthetic intermediates for applications in materials science. The aims of this work are to synthesis a novel isoxazole and analyze its structural and photophysical properties for application in electronic organic materials. The novel bis (phenylisoxazolyl) benzene compound was synthesized in four steps and characterized by NMR, high resolution mass spectrometry, differential thermal analysis, infrared spectroscopy, cyclic voltammetry, ultraviolet–visible spectroscopy, fluorescence spectroscopy, DFT and TDDFT calculations. The molecule presented optical absorption in the ultraviolet region (from 290 nm to 330 nm), with maximum absorption length centered at 306 nm. The molar extinction coefficients (ε), fluorescence emission spectra and quantum efficiencies in chloroform and dimethylformamide solution were determined. Cyclic voltammetry analysis was carried out for estimating the HOMO energy level and these properties make it desirable material for photovoltaic device applications. Finally, the excited-state properties of present compound were calculated by time-dependent density functional theory (TDDFT).