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132 results on '"Ronconi, Célia M."'

2. Zika Virus NS1 Protein Detection Using Gold Nanoparticle‐Assisted Dynamic Light Scattering.

Author

D'Amato, Dayenny L., Bessa, Isabela A. A., Souza, Ana Beatriz C., Mendes‐Monteiro, Lucas, Mohana‐Borges, Ronaldo, Allonso, Diego, Ligiero, Carolina B. P., and Ronconi, Célia M.

Subjects
ARBOVIRUS diseases, VIRAL proteins, ZIKA virus, GOLD nanoparticles, DENGUE viruses
Abstract

The Zika virus (ZIKV) is a global health threat due to its rapid spread and severe health implications, including congenital abnormalities and neurological complications. Differentiating ZIKV from other arboviruses such as dengue virus (DENV) is crucial for effective diagnosis and treatment. This study presents the development of a biosensor for detecting the ZIKV non‐structural protein 1 (NS1) using gold nanoparticles (AuNPs) functionalized with monoclonal antibodies employing dynamic light scattering (DLS). The biosensor named ZINS1‐mAb‐AuNP exhibited specific binding to the ZIKV NS1 protein, demonstrating high colloidal stability indicated by a hydrodynamic diameter (DH) of 140 nm, detectable via DLS. In the absence of the protein, the high ionic strength medium caused particle aggregation. This detection method showed good sensitivity and specificity, with a limit of detection (LOD) of 0.96 μg mL−1, and avoided cross‐reactivity with DENV2 NS1 and SARS‐CoV‐2 spike proteins. The ZINS1‐mAb‐AuNP biosensor represents a promising tool for the early and accurate detection of ZIKV, facilitating diagnostic and treatment capabilities for arboviral infections. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Hydroxyapatite Nanocrystals Integrated into Mesoporous Silica for Sustained Delivery of Doxorubicin.

Author

Bessa, Isabela A. A., Cruz, João Victor R., da Silva, Aline F. M., D'Amato, Dayenny L., Ligiero, Carolina B. P., Gomes-da-Silva, Natália C., Archanjo, Bráulio S., Pinto, Luis Felipe R., Santos-Oliveira, Ralph, Rossi, Alexandre M., da Costa, Nathália M., and Ronconi, Célia M.

Abstract

The combination of mesoporous silica nanoparticles (MSNs) with a second material to produce nanocarriers is a strategy to enhance their functionalities. Hydroxyapatite (HAP) is a judicious choice due to its high biocompatibility and osteoconductive and noninflammatory behavior. Herein, we explored the independent advantages of MSNs and HAP by incorporating HAP nanocrystals in the MSNs using different approaches. We demonstrated that by adjusting the synthesis conditions, we modulated, at the nanoscale level, how HAP was integrated into mesoporous silica, either as separated phases (MSN-HAP) or as combined phases in one structure (HAP@MSN). The materials MSN-HAP and HAP@MSN were loaded with doxorubicin (DOX), as a drug model, and were compared with MSNs regarding their physicochemical characteristics, DOX release kinetics, cytotoxicities toward esophagus 2D and 3D (spheroids) cancer cells, and in vivo biochemical effects. The produced DOX-loaded nanocarriers showed tuned properties; e.g., not only did HAP retard the DOX release in comparison with pure MSNs, but also the way the HAP was integrated dictated the kinetics of DOX release. The cytotoxicity studies showed that the presence of HAP prolonged the DOX effect. The biochemical analysis of MSN-HAP-DOX and HAP@MSN-DOX indicated a transient alteration in the liver metabolism, whereas HAP@MSN-DOX had a modest effect on mouse fat metabolism. Therefore, benefiting from the bone-regeneration feature of HAP and the controlled drug release, we envision that MSN-HAP and HAP@MSN are promising materials for clinical translation as long-acting release formulations, especially for bone cancer treatment. [ABSTRACT FROM AUTHOR]

Published
2024
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10. A new photoluminescent terbium(III) coordination network constructed from 1,2,4,5-benzenetetracarboxylic acid: Synthesis, structural characterization and application as a potential marker for gunshot residues

Author

Silva, Mariane A., de Campos, Nathália R., Ferreira, Leonildo A., Flores, Leonã S., Júnior, Júlio C.A., dos Santos, Guilherme L., Corrêa, Charlane C., dos Santos, Thiago C., Ronconi, Célia M., Colaço, Marcos V., Simões, Tatiana R.G., Marques, Lippy F., and Marinho, Maria Vanda

Published
2019
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14. Effect of activated biochar as a low-cost catalyst on the quality of catalytic intermediate co-pyrolysis oil from waste polystyrene and green coconut pericarp

Author

Arantes, Heryson T.L., primary, Machado, Marta A., additional, Santoro, Mariana C., additional, Freitas, Jair C.C., additional, Ronconi, Célia M., additional, Ligiero, Carolina B.P., additional, Cassini, Sérvio T.A., additional, Sampaio, Igor C.F., additional, and Luz, Priscilla P., additional

Published
2023
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18. Responsive Supramolecular Devices Assembled from Pillar[5]arene Nanogate and Mesoporous Silica for Cargo Release

Author

da Silva, Aline F. M., primary, da Costa, Nathalia M., additional, Fernandes, Tamires S., additional, Bessa, Isabela A. A., additional, D’Amato, Dayenny L., additional, Senna, Carlos Alberto, additional, Lohan-Codeço, Matheus, additional, Nascimento, Vanessa, additional, Palumbo, Antonio, additional, Archanjo, Braulio S., additional, Pinto, Luis Felipe R., additional, dos Santos, Thiago C., additional, and Ronconi, Célia M., additional

Published
2022
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19. Niobium‐doped Hematite Photoanodes Prepared through Low‐Cost Facile Methods for Photoelectrochemical Water Splitting.

Author

Melo, Mauricio A., Brito, Igor M., Mello, João V. S. B., Rocha, Pamela S. M., Bessa, Isabela A. A., Archanjo, Braulio S., Miranda, Fabio S., Cassella, Ricardo J., and Ronconi, Célia M.

Subjects
ELECTROPHORETIC deposition, HEMATITE, PHOTOELECTROCHEMICAL cells, CHEMICAL yield, FOSSIL fuels, NANOPARTICLE size, DYE-sensitized solar cells
Abstract

Producing solar fuels through semiconductor‐based photocatalytic water splitting is one of the main options for worldwide employment of non‐fossil energy sources. Nonetheless, the relatively low efficiency of the known photocatalysts, the high prices of composing elements, and the costly preparation methods render expensive devices that would not be economically competitive with fossil energy sources. Herein, we present a facile method for the preparation of both round hematite (Fe2O3) nanoparticles, with average diameter of (56±7) nm, and of niobium‐doped hematite nanoparticles with similar size and morphology. Thin films of these nanoparticles were assembled through electrophoretic deposition, resulting in homogeneous photoanodes with nanometer thickness that can split water, under simulated solar irradiation, to produce oxygen in a photoelectrochemical cell. The optimization of the film composition and thickness resulted in the improvement of the photocurrent from 352.3 to 1,342.5 μA cm−2 at 1.23 V vs RHE for the pristine hematite and Nb‐doped hematite, respectively, both with thickness of (499±63) nm. This enhancement in the oxidation reaction yield is a clear consequence of the improvement of charge carriers transport along the nanoparticle structure due to niobium doping and adequate light absorption/charge transfer balance of the photoelectrode under operation. [ABSTRACT FROM AUTHOR]

Published
2023
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29. A reversible, switchable pH-driven quaternary ammonium pillar[5]arene nanogate for mesoporous silica nanoparticles

Author

Santos, Evelyn C. S., primary, dos Santos, Thiago C., additional, Fernandes, Tamires S., additional, Jorge, Fernanda L., additional, Nascimento, Vanessa, additional, Madriaga, Vinicius G. C., additional, Cordeiro, Pâmella S., additional, Checca, Noemi R., additional, Da Costa, Nathalia Meireles, additional, Pinto, Luís Felipe Ribeiro, additional, and Ronconi, Célia M., additional

Published
2020
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30. Spin-frustration with two quasi-degenerated spin states of a copper(ii) heptanuclear complex obtained from an amino acid ligand

Author

Matos, Catiúcia R. M. O., primary, S. Junior, Henrique C., additional, D'Amato, Dayenny L., additional, de Souza, Acácio S., additional, Pinheiro, Sérgio, additional, Guedes, Guilherme P., additional, Ferreira, Glaucio B., additional, Alves, Odivaldo C., additional, de Almeida, Filipe B., additional, Garcia, Flávio, additional, and Ronconi, Célia M., additional

Published
2020
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31. A Carbocationic Triarylmethane‐Based Porous Covalent Organic Network.

Author

Freitas, Sunny K. S., Oliveira, Felipe L., Santos, Thiago C., Hisse, Danilo, Merlini, Claudia, Ronconi, Célia M., and Esteves, Pierre M.

Subjects
ELECTRIC conductivity, POROUS materials, MESOPOROUS materials, NANOPOROUS materials, SURFACE area, CARBON dioxide, GASES
Abstract

A thermally stable carbocationic covalent organic network (CON), named RIO‐70 was prepared from pararosaniline hydrochloride, an inexpensive dye, and triformylphloroglucinol in solvothermal conditions. This nanoporous organic material has shown a specific surface area of 990 m2 g−1 and pore size of 10.3 Å. The material has CO2 uptake of 2.14 mmol g−1 (0.5 bar), 2.7 mmol g−1 (1 bar), and 6.8 mmol g−1 (20 bar), the latter corresponding to 3 CO2 molecules adsorbed per pore per sheet. It is shown to be a semiconductor, with electrical conductivity (σ) of 3.17×10−7 S cm−1, which increases to 5.26×10−4 S cm−1 upon exposure to I2 vapor. DFT calculations using periodic conditions support the findings. [ABSTRACT FROM AUTHOR]

Published
2021
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32. ESTERIFICAÇÃO E TRANSESTERIFICAÇÃO HOMOGÊNEA DE ÓLEOS VEGETAIS CONTENDO ALTO TEOR DE ÁCIDOS GRAXOS LIVRES

Author

Vieira, José Sebastião C., Sousa, Taís L., Rosas, Luzilene S., Lima, Ana L., Ronconi, Célia M., and Mota, Cláudio J. A.

Subjects
esterification, food and beverages, biodiesel, Vegetable oils, complex mixtures, transesterification
Abstract

The high free fatty acids content in some vegetable oils can have a negative impact in the sustainable production of biodiesel. The previous treatment of these feedstock oils can contribute to the reduction of the process total costs as well as the environment, turning the biodiesel a more competitive in relation to the fossil diesel. The aim of this work was to adequate low cost vegetable oils to the production of biodiesel by homogeneous catalysis. The feedstock was evaluated by its acidity, by its free fatty acids content, by its saponification index and its specific mass. The Biodiesel produced was characterized by high performance liquid chromatography. The results showed significant free fatty acids and humidity content, which are the main factors in the raising of the production costs. The results also showed that the esterification of the vegetable oils reduced its acidity in about 99%. The transesterification of the Brazilian nut oil previously esterified yields about 98% of biodiesel. Even though the biodiesel processing presents an alternative to the energetic self-sufficiency of Brazil, there are many challenges in the adequacy of these high acidity oils and fats for its production.

Published
2018

37. Modeling controlled potassium release from phlogopite in solution: exploring the viability of using crushed phlogopitite rock as an alternative potassium source in Brazilian soil

Author

Silva, Adriana de A. S. da, Sampaio, João A., Luz, Adão B. da, França, Sílvia C. A., and Ronconi, Célia M.

Subjects
potassium release, phlogopite, potassium source, kinetic studies, phlogopitite
Abstract

The chemical and mineralogical properties of phlogopitite, a rock containing the mineral phlogopite, were studied aiming at employment as an alternative source of potassium. Mineralogical characterization of this rock was performed using X-ray diffractometry, X-ray fluorescence, scanning electron microscopy and infrared spectroscopy. According to the results, phlogopite contains approximately 82.6 g K2O kg-1 (ca. 9%). The kinetics involved in the release of the potassium ions from the mineral were examined using acidic solutions (nitric, citric, oxalic and Mehlich-1) and a salt solution (sodium tetraphenylboron, Na[B(C6H5)4]). The experimental results from the kinetic studies were used to determine the mathematical relationship between the concentration of potassium released and the reaction time. As propriedades químicas e mineralógicas do flogopitito, uma rocha que contém flogopita, foram estudadas tendo em vista o emprego como fonte alternativa de potássio. A caracterização mineralógica da rocha foi realizada por difratometria de raios X, fluorescência de raios X, microscopia eletrônica de varredura e espectroscopia na região do infravermelho. De acordo com os resultados, flogopita contém 82,6 g K2O kg-1 (ca. 9%). A cinética de liberação do íon potássio a partir do mineral foi avaliada em meio ácido (nítrico, cítrico, oxálico e Mehlich-1) e em uma solução salina (tetrafenilborato de sódio, Na[B(C6H5)4]). Os resultados experimentais obtidos a partir dos estudos cinéticos foram ajustados para determinar uma relação matemática entre a concentração de íons potássio liberada em solução e o tempo de liberação.

Published
2013

38. Modified silica nanoparticles with an Aminonaphthoquinone

Author

Silveira, Gleiciani Q, Ronconi, Célia M, Vargas, Maria D, San Gil, Rosane A. S, and Magalhães, Alvicler

Subjects
multifunctional material, naphthoquinones, solid state 13C and 29Si NMR, silica nanoparticles
Abstract

The synthesis and characterization of silica nanoparticles (NPs) covalently modified with an aminonaphthoquinone are reported. The aminopropylsilicagelnaphthoquinone (APSGNQ) was obtained by nucleophilic substitution of 2-methoxy-1,4-naphthoquinone with aminopropylsilicalgel (APSG) NPs. Solid state 13C and 29Si nuclear magnetic resonance spectra confirmed that the naphthoquinone is covalently bonded to APSG. Due to the solubility of APSGNQ in common organic solvents, solution ultraviolet-visible spectroscopy was used to determine the amount of naphthoquinone on the NPs surface (0.56 mmol of incorporated naphthoquinone per gram of APSGNQ) by comparison with the spectrum of 2-aminobutyl-1,4-naphthoquinone (ABNQ). Elemental analysis indicated that about 8% of the surface propylamine remained unreacted in APSGNQ. These multifunctional silica NPs have potential in medical applications. Nanopartículas de sílica (NPs) modificadas covalentemente com uma aminonaftoquinona foram sintetizadas e caracterizadas. A aminopropilsilicagelnaftoquinona (APSGNQ) foi obtida por substituição nucleofílica do grupo metóxi da 2-metóxi-1,4-naftoquinona por NPs modificadas com o grupo aminopropil (APSG). Os espectros de ressonância magnética nuclear de 13C e 29Si no estado sólido confirmaram que a naftoquinona encontra-se ligada covalentemente à aminopropilsilicagel. Como o composto APSGNQ é solúvel em solventes orgânicos comuns, foi possível quantificar o ancoramento da naftoquinona na superfície das NPs modificadas por espectroscopia no ultravioleta-visível (0,56 mmol de naftoquinona ancorada por grama de APSGNQ), por comparação com o espectro do composto análogo 2-aminobutil-1,4-naftoquinona (ABNQ). Os dados das análises elementares indicaram que aproximadamente 8% da propilamina presente na superfície do composto APSGNQ não reagiu com a metóxinaftoquinona. Essas NPs de sílica multifuncionais têm potencial para aplicações médicas.

Published
2011

40. Degradation of magnetic nanoparticles mimicking lysosomal conditions followed by AC susceptibility

Author

AXA Research Fund, Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), European Commission, Gutiérrez, Lucía, Romero, Sonia, Silva, Gustavo B. da, Costo, Rocío, Vargas, María D., Ronconi, Célia M., Serna Pereda, Carlos J., Veintemillas-Verdaguer, S., Morales, M. P., AXA Research Fund, Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), European Commission, Gutiérrez, Lucía, Romero, Sonia, Silva, Gustavo B. da, Costo, Rocío, Vargas, María D., Ronconi, Célia M., Serna Pereda, Carlos J., Veintemillas-Verdaguer, S., and Morales, M. P.

Abstract

[Background] A deeper knowledge on the effects of the degradation of magnetic nanoparticles on their magnetic properties is required to develop tools for the identification and quantification of magnetic nanoparticles in biological media by magnetic means., [Methods] Citric acid and phosphonoacetic acid-coated magnetic nanoparticles have been degraded in a medium that mimics lysosomal conditions. Magnetic measurements and transmission electron microscopy have been used to follow up the degradation process., [Results] Particle size is reduced significantly in 24 h at pH 4.5 and body temperature. These transformations affect the magnetic properties of the compounds. A reduction of the interparticle interactions is observed just 4 h after the beginning of the degradation process. A strong paramagnetic contribution coming from the degradation products appears with time., [Conclusions] A model for the in vivo degradation of magnetic nanoparticles has been followed to gain insight on the changes of the magnetic properties of iron oxides during their degradation. The degradation kinetics is affected by the particle coating, in our case being the phosphonoacetic acid-coated particles degraded faster than the citric acid-coated ones.

Published
2015

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