Uma montagem experimental para a medida de fluorescência

Pavoni, Juliana Fernandes; Neves-Junior, Wellington Furtado Pimenta; Spiropulos,; Araújo, David

doi:10.1590/s1806-11172014000400018

Cited by 6 publications

(8 citation statements)

References 2 publications

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“…Fluorescent molecules with the ability to absorb ultraviolet radiation and to emit in a range of wavelengths greater than that absorbed, that is, in the visible region, are extremely important to biomedical applications [ 21 ]. The characteristic time for the fluorescence process (on the order of 10 −9 s) depends on the interaction of molecules with the surrounding environment, being attractive for the evaluation of several phenomena from the biophysical properties of molecules [ 21 ]. Thus, the photophysical study of the naphth[1,2- d ]imidazoles IM1 – IM7 synthesized was carried out to verify their potential to emission of molecules for potential use in theranostic systems.…”

Section: Resultsmentioning

confidence: 99%

Naphth[1,2-d]imidazoles Bioactive from β-Lapachone: Fluorescent Probes and Cytotoxic Agents to Cancer Cells

et al. 2023

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Theranostics combines therapeutic and imaging diagnostic techniques that are extremely dependent on the action of imaging agent, transporter of therapeutic molecules, and specific target ligand, in which fluorescent probes can act as diagnostic agents. In particular, naphthoimidazoles are potential bioactive heterocycle compounds to be used in several biomedical applications. With this aim, a group of seven naphth[1,2-d]imidazole compounds were synthesized from β-lapachone. Their optical properties and their cytotoxic activity against cancer cells and their compounds were evaluated and confirmed promising values for molar absorptivity coefficients (on the order of 103 to 104), intense fluorescence emissions in the blue region, and large Stokes shifts (20–103 nm). Furthermore, the probes were also selective for analyzed cancer cells (leukemic cells (HL-60). The naphth[1,2-d]imidazoles showed IC50 between 8.71 and 29.92 μM against HL-60 cells. For HCT-116 cells, values for IC50 between 21.12 and 62.11 μM were observed. The selective cytotoxicity towards cancer cells and the fluorescence of the synthesized naphth[1,2-d]imidazoles are promising responses that make possible the application of these components in antitumor theranostic systems.

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Section: Resultsmentioning

confidence: 99%

Naphth[1,2-d]imidazoles Bioactive from β-Lapachone: Fluorescent Probes and Cytotoxic Agents to Cancer Cells

et al. 2023

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“…As diferentes radiações emitidas, ao serem absorvidas pelo revestimento fluorescente, decaem quase instantaneamente (intervalo de tempo da ordem de 10 −9 s), com radiação distribuída a partir de níveis de energia ligeiramente menores que a emissão original, gerando a radiação visível observada. Neste fenômeno de fluorescência [20], dependendo da interação com o material do revestimento fluorescente e da energia dispendida para emissão de outros elementos presentes na composição das lâmpadas, a intensidade original das linhas próprias emitidas pelo mercúrioé afetada. Por isso, em nossa análise, para a seleção das linhas do mercúrio tomadas como referência para a calibração, não só a intensidade relativa, mas a capacidade das linhas consideradas de promoverem o melhor ajuste global de calibração foi considerado.…”

Section: Linhas Espectrais De Referência No Nistunclassified

Explorando quantitativamente observações feitas com espectrógrafos caseiros por meio de recursos digitais

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2021

Rev. Bras. Ensino Fís.

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Neste trabalho expomos um método para obter calibrações em comprimento de onda de espectros para os quais não se conhece previamente as linhas espectrais, aplicando-a em uma atividade didática prática utilizando espectros obtidos de espectrógrafos caseiros. Apresentamos a configuração instrumental para obtenção simultânea dos espectros de interesse e de calibração. Com os espectros registrados aplicamos técnicas de processamento de imagens para tratar, otimizar a extrair os dados de interesse. Para o procedimento de calibração indicamos como pesquisar pelos valores padrões no banco de dados de linhas espectrais do NIST. Uma planilha eletrônica foi elaborada com o propósito de ilustrar o processo de calibração dos espectros por meio de procedimentos usando o software DS9. Demonstramos a aplicação do procedimento de calibração nos espectros unidimensional e bidimensional no caso do espectro de lâmpada de vapor de hélio, com a qual recuperamos o comprimento de onda das linhas espectrais com resíduos inferiores a 4 nm. Por fim apresentamos sugestões de algumas atividades didáticas práticas que podem ser conduzidas por meios dos procedimentos aqui expostos utilizando observações de fontes luminosas do cotidiano.

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“…Fluorescence is a phenomenon that occurs in various biological processes and systems where molecules absorb and emit radiation in a spectral range of 475 and 508 nanometers (nm) [54]. This phenomenon has become a powerful tool in investigations in studies at the molecular level and dynamics of living systems [55].…”

Section: Fluorescence Measurement Systemmentioning

confidence: 99%

“…Several studies have enabled the development of new small and cheap fluorometers by using light emitting diodes (LEDs) that turn blue sign [54] where results were found favorable.…”

Section: Fluorescence Measurement Systemmentioning

confidence: 99%

“…The use of these devices in the area of biosystems is becoming popular mainly due to their high reconfigurability and SoC (System on a Chip Solutions). The methodology proposed here is the following: the processing unit (FPGA) sends pulses to LEDs with emission spectrum of 475 nm, directing the light through the emission filter that only allows the passage of emission spectrum generated by the LED [54]; often, a dichroic mirror directs the light from the LED to the sample; the genetically modified bacteria with the GFP gene are excited by the incidence of the light and fluoresces in the range of 508 nm; an excitation filter of 508 nm only allows the passage of the light in the range of 508 nm. The fluorescence emission will be assessed by a photodiode which converts the number of photons received in a corresponding number of electrons [61].…”

Section: Perspectivesmentioning

confidence: 99%

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Biosensors Used for Quantification of Nitrates in Plants

et al. 2016

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Nitrogen is essential for the plant because it is used for the production of chlorophyll, proteins, nucleic acids, amino acids, and other cellular compounds; nitrogen is available in two forms: ammonium and nitrate. Several tools have been used to quantify nitrates in plants such as the Kjeldahl method and Dumas combustion digestion; however, they are destructive and long time-consuming methods. To solve these disadvantages, methods such as selective electrodes, optical sensors, reflectometers, and images based sensors have been developed; nonetheless, all these techniques show interference when carrying out measurements. Currently, biosensors based on genetic constructions, based on the response of promoter gene fused to Gene Fluorescent Protein (GFP), are gaining popularity, because they improve the accuracy of measurements of nitrate by avoiding the interference of carriers ion, high salt conditions, and other factors. The present review shows the different methods to quantify the nitrogen in plants; later, a biosensors perspective is presented, mainly focused on biosensors based on organism genetically modified. The review presents a list of promoter and reporter genes that could be used to develop different kind of sensors, and a perspective of sensors to measure quantitatively the nitrogen is presented.

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Uma montagem experimental para a medida de fluorescência

Cited by 6 publications

References 2 publications

Naphth[1,2-d]imidazoles Bioactive from β-Lapachone: Fluorescent Probes and Cytotoxic Agents to Cancer Cells

Naphth[1,2-d]imidazoles Bioactive from β-Lapachone: Fluorescent Probes and Cytotoxic Agents to Cancer Cells

Explorando quantitativamente observações feitas com espectrógrafos caseiros por meio de recursos digitais

Biosensors Used for Quantification of Nitrates in Plants

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