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Synthesis and properties of merocyanine dyes derived from N-aryl-substituted pyridinium salts and cyanoacetic acids
摘要： A series of merocyanine dyes were synthesized by two-component condensation of N-aryl-4-picolinium salts and cyanoacetic acid derivatives. Physicochemical properties of the synthesized dyes were studied.
关键词： protonation,4-picolinium salts,merocyanine dyes,spectral properties,heterocycles
更新于2025-09-10 09:29:36
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Design of Thermochromic Luminescent Dyes Based on the Bis(o-carborane)-Substituted Benzobithiophene Structure
摘要： To obtain solid-state emissive materials having stimuli-responsive luminescent chromic properties without phase transition, benzobithiophenes modified with two o-carborane units having various substituents in the adjacent phenyl ring in o-carborane were designed and synthesized. Their emission colors were strongly affected not only by the substituents at the para-position of the phenyl ring but also by molecular distribution in the solid state. In particular, the emission colors were changed by heating without crystal phase transition. It was proposed that their thermochromic properties were correlated not with isomerization but with the molecular motion at the distorted benzobithiophene moiety.
关键词： Thermochromic,Bis(o-carborane)-Substituted Benzobithiophene,Solid-State Emissive Materials,Stimuli-Responsive,Luminescent Dyes
更新于2025-09-10 09:29:36
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Scattering-/absorption-mode light shutters based on dye-doped fingerprint chiral textures
摘要： Scattering-/absorption-mode light shutters based on dye-doped fingerprint chiral textures (DdFCTs) are demonstrated. DdFCTs in a liquid crystal (LC) cell treated with homeotropic alignment are initially stable FCTs due to the vertical surface anchoring force (SAF). The LCs completely rotate to homeotropic orientation from stable FCTs by applying a suitable operation voltage (Vop). Furthermore, when the Vop is switched off, the LCs transform into temporary focal conic textures with lifetimes of few seconds from the homeotropic orientation, the LCs then transform into unstable FCTs. Finally, the unstable FCTs spontaneously return to the initial stable FCTs. The light absorption of DdFCTs in the stable FCTs/unstable FCTs/field-induced multi-domain FCTs is independent of the polarization of the incident light. The operation mechanism of the proposed DdFCTs is also discussed. Most importantly, the response time and the required Vop to rotate all LCs to homeotropic orientation in DdFCTs from stable FCTs in LC cells treated with homeotropic alignment layers are respectively shorter and lower than those in common dye-doped cholesteric LCs (DdCLCs) from stable planar textures in LC cells treated with homogeneous alignment layers. Comparing with DdCLCs, about 20% Vop can be reduced in DdFCTs. The cause can be understood since the Vop applied onto the DdFCTs is fully dedicated to unwind the helical structures.
关键词： Cholesterics,Liquid crystals,Scattering,Dichroic dyes,Light shutter,Absorption
更新于2025-09-10 09:29:36
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ZnO nanospheres based simple hydrothermal route for photocatalytic degradation of azo dye
摘要： This novel work presents a promising application to use Zinc oxide nanospheres as nanocatalysts in photocatalytic degradation of methyl orange dye. The hydrothermal route was utilized in the synthesis process of ZnO nanospheres. The size of the synthesized ZnO nanoparticles is around 200-250 nm diameter. The synthesized nano-oxides were characterized utilizing several instruments such as X-ray diffraction, Brunauer, Emmett, and Teller (BET), and scanning electron microscope (SEM). The resulting nanoparticles are utilized as an efficient tool for degradation of methyl orange (MO) dye under UV radiation. Essential parameters were studied on degradation process involving the initial concentration of MO, pH, stirring the solution, dose of the ZnO nanospheres, the oxygen content of the solution, calcination of the nanomaterials. All activity experiments under UV radiation provide excellent results for the degradation process of MO. Also, the recovery of ZnO nanomaterials was investigated based on the photocatalytic process efficiency. The results show the high possibility of reuse ZnO nanospheres for several photocatalytic processes. Also, the nanocatalysts were applied for a real environmental sample with providing high photocatalytic performance.
关键词： methyl orange,ZnO nanospheres,photocatalytic degradation,hydrothermal method,azo dyes
更新于2025-09-10 09:29:36
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CAHM1: A Theory Based Proposal for a New DSSC D-A-π-A Dye
摘要： The initial charge separation process in Dye Sensitized Solar Cells (DSSC) is crucial to their e?ciency. An interesting strategy is to employ D-π-A (donor-π-acceptor) dyes, since the push-pull e?ect may avoid charge recombination instead of electron transfer to the semiconductor. In this work, we propose a method to design a photosensitizer based exclusively on quantum mechanics calculations. Our analysis focused on the in- ?uence of (i) di?erent donor groups and (ii) conformational contributions, on electronic properties aiming to enhance the push-pull e?ect and the alignment with the CB. Based on this study, we propose a new dye, CAHM1, where the selected substituent have a donor character and, at the same time, enable a twisted geometry that enhances charge separation of the ?rst excited state. The system is characterized by a marked push-pull e?ect, as well as, presents absorption spectrum and LUMO energy in a suitable region for DSSC devices.
关键词： Dye Sensitized Solar Cells,DSSC,push-pull effect,CAHM1,quantum mechanics calculations,D-π-A dyes
更新于2025-09-10 09:29:36
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Super Blinking and Biocompatible Nanoprobes Based on Dye Doped BSA Nanoparticles for Super Resolution Imaging
摘要： As one of the super-resolved optical imaging technique, single molecule localization microscopy (SMLM) imaging techniques, SMLM has one particular request for the fluorophores, that is, continuous “on” and “off” behaviors of their signals (referred to as “blinking”). Hence, we present here a kind of Super Blinking and biocompatible Nanoprobes (denoted as SBNs) for SMLM. The SBNs have two main advantages, first, they possess an outstanding fluorescence blinking. Second, they are biocompatible since they are based on bovine serum albumin (BSA). The SBNs are fabricated by doping organic dyes into BSA nanoparticles (NPs). We fabricated two kinds of SBNs, one was doped with Alexa Fluor 647 (A647) and the other was doped with Alexa Fluor 594 (A594). Especially for A594 doped SBNs, the improved blinking of A594 doped SBNs induced a better localization precision as compared with A594 alone. Moreover, SMLM imaging of breast cancer cells and exosomes using the SBNs was successfully realized with high spatial resolutions. The work demonstrated here provides a new strategy to prepare novel kinds of super blinking fluorescent agents for SMLM, which broadens the selection of suitable fluorophores for SMLM.
关键词： BSA nanoparticles,single molecule localization microscopy,super blinking,dyes,localization precision
更新于2025-09-10 09:29:36
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Self-healing dyes for super-resolution fluorescence microscopy
摘要： In recent years, optical microscopy techniques have emerged that allow optical imaging at unprecedented resolution beyond the diffraction limit. These techniques exploit photostabilizing buffers to enable photoswitching and/or the enhancement of fluorophore brightness and stability. A major drawback with the use of photostabilizing buffers, however, is that they cannot be used in live cell imaging. In this paper, we tested the performance of self-healing organic fluorophores, which undergo intramolecular photostabilization, in super-resolution microscopy examining both targeted (stimulated emission depletion (STED) microscopy) and stochastic readout (stochastic optical reconstruction microscopy (STORM)). The overall goal of the study was to identify dyes and conditions that lead to improved spatial and temporal resolution of both techniques without the need for mixtures of photostabilizing agents in the imaging buffer. As a result of previously shown superior performance, we identified an ATTO647N-photostabilizer conjugate as a potential candidate for STED microscopy. We have here characterized the photostability and resulting performance of this nitrophenylalanine (NPA) conjugate of ATTO647N on oligonucleotides in STED microscopy. We found that the superior photophysical performance resulted in optimal STED imaging and demonstrated that single-molecule fluorescent transients of individual fluorophores can be obtained with both the excitation- and STED-laser. In similar experiments, we also tested a nitrophenylacetic acid conjugate of STAR635P, another frequently used dye in STED microscopy, and present a characterization of its photophysical properties. Finally, we performed an analysis of the photoswitching kinetics of self-healing Cy5 dyes (containing trolox, cyclooctatetraene and NPA-based stabilizers) in the presence of Tris(2-carboxyethyl) phosphine and cysteamine, which are typically used in STORM microscopy. In line with previous work, we found that intramolecular photostabilization strongly influences photoswitching kinetics and requires careful attention when designing STORM-experiments. In summary, this contribution explores the possibilities and limitations of self-healing dyes in super-resolution microscopy of differing modalities.
关键词： STORM,super-resolution microscopy,fluorescent dyes,STED,fluorescence microscopy
更新于2025-09-09 09:28:46
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Surface-enhanced Raman spectroscopy (SERS) in cotton fabrics analysis
摘要： This article presents some aspects of application the dispersive Micro-Raman Spectroscopy in textile fibers analysis. Research were dedicated to the methodology of surface enhancement Raman spectroscopy (SERS) studies on cotton fabric and possibility of its application in fibers characterization. Studies were carried out on dyed cotton fabrics modified by silver nanowires (AgNWs). Three reactive dyes (blue, yellow, red) and four color intensities (0.5%, 1%, 2% and 5%) were used. AgNWs colloid was deposited on undyed and dyed cotton fabrics by dipping and drying method. Dyed fabrics were examined by spectroscopic methods: FTIR ATR, Raman, UV-Vis Diffuse Reflectance Spectroscopy, Fluorescence Spectroscopy. Raman signal enhancement phenomena occurring on the silver nanoparticles increases the possibility of fiber and dye identification especially in the case of dyes used in cotton dyeing reveals fluorescence.
关键词： UV-Vis Diffuse Reflectance Spectroscopy,SERS,Fluorescence Spectroscopy,reactive dyes,FTIR ATR,Micro-Raman spectroscopy,Cotton fibers
更新于2025-09-09 09:28:46
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Isomerization and Properties of Isomers of Carbocyanine Dyes
摘要： One of the important features of polymethine (cyanine) dyes is isomerization around one of C–C bonds of the polymethine chain. In this review, spectral properties of the isomers, photoisomerization and thermal back isomerization of carbocyanine dyes, mostly meso-substituted carbocyanine dyes, are considered. meso-Alkyl-substituted thiacarbocyanine dyes are present in polar solvents mainly as cis isomers and, hence, exhibit no photoisomerization, whereas in nonpolar solvents, in which the dyes are in the trans form, photoisomerization takes place. In contrast, 3,3′-diethyl-9-(2-hydroxy-4-methoxyphenyl)thiacarbocyanine occur as trans isomers and exhibit photoisomerization in both polar and nonpolar solvents. The behavior of these dyes may be explained by the fact that the phenyl ring of the substituent in their molecules can be twisted at some angle, removing the substituent from the plane of the molecule and reducing its steric effect on the conformation of the trans isomer. In some cases, photoisomerization of cis isomers of meso-substituted carbocyanine dyes is also observed (for some meso-alkyl-substituted dyes complexed with DNA and chondroitin-4-sulfate; for 3,3′-diethyl-9-methoxythiacarbocyanine in moderate polarity solvents). The cycle photoisomerization–thermal back isomerization of cyanine dyes can be used in various systems of information storage and deserves further investigation using modern research methods.
关键词： isomerization,meso-substituted cyanines,trans and cis isomers,carbocyanine dyes
更新于2025-09-09 09:28:46
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Flow Cytometry - Select Topics || The Multiplexing of Assays for the Measurement of Early Stages of Apoptosis by Polychromatic Flow Cytometry
摘要： The detection of apoptosis has been a stalwart application for flow cytometric analysis for decades and this review of flow cytometric methods to detect early stages of apoptosis includes the use of the pivotal assay to detect early and late apoptosis, the Annexin V assay which when multiplexed with biologically functional fluorescent dyes to measure mitochondrial function and Reactive Oxygen Species (ROS) generation allows further identification of functionally different subsets within apoptotic populations. Here we show how this polychromatic approach can be used to demonstrate which subset of cells show changes in mitochondrial function and when ROS is generated in a time dependent manner. This polychromatic approach to flow cytometry leads to the identification of over ten sub-populations of cells during classic apoptosis or programmed cell death (PCD).
关键词： Polychromatic,ROS,DNA dyes,Annexin V,MitoTracker
更新于2025-09-09 09:28:46