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Discrete Wavelet Transform (DWT) Assisted Partial Least Square (PLS) Analysis of Excitation-Emission Matrix Fluorescence (EEMF) Spectroscopic Data Sets: Improving the Quantification Accuracy of EEMF Technique
摘要： In the present work, it is shown that quantitative estimation efficiency of the partial least square (PLS) calibration model can be significantly improved by pre-processing the EEMF with discrete wavelet transform (DWT) analysis. The application of DWT essentially reduces the volume of data sets retaining all the analytically relevant information that subsequently helps in establishing a better correlation between the spectral and concentration data matrices. The utility of the proposed approach is successfully validated by analyzing the dilute aqueous mixtures of four fluorophores having significant spectral overlap with each other. The analytical procedure developed in the present study could be useful for analyzing the environmental, agricultural, and biological samples containing the fluorescent molecules at low concentration levels.
关键词： Partial least square analysis,Discrete wavelet analysis,Fluorophores,Wavelet analysis,Excitation-emission matrix fluorescence
更新于2025-09-09 09:28:46
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Triarylmethane Fluorophores Resistant to Oxidative Photobluing
摘要： Spectral stability of small-molecule fluorescent probes is required for correct interpretation and reproducibility of multicolor fluorescence imaging data, in particular under high (de)excitation light intensities of super-resolution imaging or in single-molecule applications. We propose a synthetic approach to a series of spectrally stable rhodamine fluorophores based on sequential Ru- and Cu-catalyzed transformations, evaluate their stability against photobleaching and photoconversion in context of other fluorophores using chemometric analysis, and demonstrate chemical reactivity of fluorophore photoproducts. The substitution patterns providing the photoconversion-resistant triarylmethane fluorophores have been identified, and the applicability of non-bluing labels in live-cell STED nanoscopy is demonstrated.
关键词： STED nanoscopy,photostability,triarylmethane fluorophores,rhodamine fluorophores,oxidative photobluing
更新于2025-09-04 15:30:14
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Recent advances in the synthesis of [ <i>a</i> ]-benzo-fused BODIPY fluorophores
摘要： This feature article summarizes the di?erent strategies for the synthesis of [a]-benzo-fused BODIPYs that have been reported in the literature until 2018. These p-extended BODIPYs are promising fluorophores for bio-imaging and organic photovoltaic applications due to both their attractive photophysical properties in the near-infrared area and their higher (photo)chemical stability compared to conventional bis-styryl derivatives. The four main strategies described in this review can be used to access either directly the expected [a]-benzo-fused BODIPYs or through the di-/tetra-hydroisoindole.
关键词： organic photovoltaic,fluorophores,near-infrared,BODIPY,bio-imaging
更新于2025-09-04 15:30:14
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Autofluorescence of Breast Cancer Proteins
摘要： Background: The intensity of the blood as well as tissue autofluorescence (fluorescence of endogenous fluorophores) shows current structure of protein mixture, its current conformation (native or denatured state), concentration or activity depending on the external and internal conditions. Nicotine amide adenine dinucleotide (NAD+) is a cofactor in redox reactions of glycolysis and the citric acid cycle in eukaryotic cells and it can be a marker of the intensity of mitochondria metabolism as well as the presence of oxygen in the cells. The concentration of reduced nicotinamide adenine dinucleotide (NADH) varies during normoxia, hypoxia and hyperoxia cells. Cancer cells increase the concentration of NADH during hypoxia and anoxia. The reason of NADH cumulation is microenvironment with low or no oxygen supply which induces glycolysis as a preferential source of energy. Glycolysis is faster, does not need oxygen but is less effective than oxidative phosphorylation. Focus: The aim of this work was to measure the structure of blood plasma and mammary gland homogenates of patients at three stages of breast cancer in comparison to healthy subjects using fluorescence analysis and atomic force microscopy. The blood plasma of patients with breast cancer had a different structure of proteins in comparison to healthy subjects. The blood plasma and homogenate of patients with breast cancer showed significant increase in autofluorescence intensity, which represents mixture of various endogenous fluorophores in particular porphyrins, collagen, NAD and flavins. Prospect: The information about complex summary of fluorescence intensity of all mixtures of endogenous fluorophores may in the future serve as rapid preliminary markers of cancer. The fluorescence analysis might be a non-traditional methodology for an early rapid diagnosis of breast cancer in the next clinical practice.
关键词： breast cancer proteins,blood plasma,Nicotine amide adenine dinucleotide,breast cancer homogenate,fluorophores,autofluorescence
更新于2025-09-04 15:30:14
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Choosing the right label for single-molecule tracking in live bacteria: side-by-side comparison of photoactivatable fluorescent protein and Halo tag dyes
摘要： Visualizing and quantifying molecular motion and interactions inside living cells provides crucial insight into the mechanisms underlying cell function. This has been achieved by super-resolution localization microscopy and single-molecule tracking in conjunction with photoactivatable fluorescent proteins (PA-FPs). An alternative labelling approach relies on genetically-encoded protein tags with cell-permeable fluorescent ligands which are brighter and less prone to photobleaching than fluorescent proteins but require a laborious labelling process. Either labelling method is associated with significant advantages and disadvantages that should be taken into consideration depending on the microscopy experiment planned. Here, we describe an optimised procedure for labelling Halo-tagged proteins in live Escherichia coli cells. We provide a side-by-side comparison of Halo tag with different fluorescent ligands against the popular photoactivatable fluorescent protein PAmCherry. Using test proteins with different intracellular dynamics, we evaluated fluorescence intensity, background, photostability, and results from single-molecule localization and tracking experiments. Capitalising on the brightness and extended spectral range of fluorescent Halo ligands, we also demonstrate high-speed and dual-colour single-molecule tracking.
关键词： Halo tag,single-molecule tracking,photoactivatable fluorescent protein,Escherichia coli,fluorophores,super-resolution microscopy,DNA-binding proteins
更新于2025-09-04 15:30:14
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Separation and Identification of Functional Groups of Molecules Responsible for Fluorescence of Biodiesel Using FTIR Spectroscopy and Principal Component Analysis
摘要： In order to separate and identify functional groups of molecules responsible for fluorescence compounds present in biodiesel, a column chromatography coupled with infrared spectroscopy and multivariate analysis was performed. A biodiesel sample was packed in a chromatographic column and the fractions obtained were used to perform the analyses. Before undergoing the separation process, the biodiesel sample was analyzed by light emitting diode (LED)-induced fluorescence and compared its spectrum with β-carotene and soybean oil patterns. The low cost and speed of analysis suggest that this technique can be used in the separation of biodiesel substances. The fluorescence emission spectra allowed identifying molecules such as β-carotene, in which the spectrum of its pattern exhibited fluorescence within a region ranging from 500 to 700 nm and chlorophyll molecules. When soybean oil is excited at around 405 nm, it features a fluorescent emission band within the region of 670 nm, which reveals the presence of chlorophyll. Infrared spectroscopy coupled with principal component analysis allowed to discriminate the fractions and to identify the functional groups of compounds present in the sample.
关键词： fluorescence,fluorophores,infrared spectroscopy,principal component analysis,biodiesel
更新于2025-09-04 15:30:14
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Turning ESIPT-Based triazine fluorophores into dual emitters: From theory to experiment
摘要： In an effort to design new dyes presenting multiple fluorescence bands, we use theoretical chemistry to guide the synthesis of new triazine structures undergoing excited-state intramolecular proton transfer (ESIPT). Starting with experimentally-known compounds showing only emission from the keto tautomer, we model several chemically-achievable substitutions aiming to sufficiently frustrate the ESIPT process by stabilising the enol structure in the electronic excited state. In a second step, some of the proposed dyes are synthesised. It turns out that the emergence of an emission band due to the enol confirms the theoretical prediction, though the observed quantum yields in solution are small as a consequence of the selection of methoxy substituents. The quantum yields are strongly improved when going to the solid-state as a result of the impeded rotations.
关键词： dual emitters,theoretical chemistry,synthesis,triazine fluorophores,ESIPT
更新于2025-09-04 15:30:14