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Waveguide optimization and its evaluation of a doped polymer optical ???ber designed for visual detection of stress
摘要： A fiber-optic strain sensor using a fluorophore-doped polymer optical fiber (POF) was fabricated at various waveguiding conditions. The effects attributed to each structural feature of the sensor were characterized by observing the sensor?s response. Two fluorophores, Coumarin 540A and Rhodamine 6G, were used to dope the core and the cladding of a poly(methyl methacrylate)-based POF, respectively. Using doped POFs with different numerical apertures (NAs), the changes in the fluorophore peaks upon the application of stress were analyzed by applying macrobending (s) to the fiber. Although the sensor response did not show linearity with respect to the NA, it was found that the shape of the Coumarin 540A-attributed peak was a factor that represented the sensor?s sensitivity. As a result, the double-cladding structure demonstrated its effectiveness in improving the stress sensitivity.
关键词： double-cladding structure,fluorophore-doped,polymer optical fiber,numerical aperture,fiber-optic strain sensor,stress sensitivity
更新于2025-09-23 15:21:01
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Discrimination of whiskies using an “add-a-fluorophore” fluorescent fingerprinting strategy
摘要： This study is concerned with the development of a fluorescent fingerprinting technique using external fluorophores. This approach is based on the quenching/dequenching of emissions by the components in the sample and therefore has wider possibilities than the common fingerprinting technique, which is based on the intrinsic fluorescence of a sample. The procedure involved mixing the sample with fluorophores in 96-well plates and recording emissions by digital photography using a Camag Visualizer 2 instrument. After RGB splitting of the images, the data were normalized and treated by principal component analysis (PCA). The quality of discrimination, characterized by the number of separate groups of points in the scores plot, was essentially improved when the images were contrasted using the bundled software. To enable interactions with a wide range of potential marker compounds, we studied six fluorophores of different chemical origins (rhodamine B on silica nanoparticles, fluorescein attached to polyethyleneimine, a Schiff base obtained using o?phthalaldehyde and polyethyleneimine, quantum dots of CdSe/CdS/ZnS, a ruthenium(II) complex with 2,2′?bipyridine (Ru(bpy)3 2+), and a zinc complex with 8?hydroxyquinoline?5?sulfonate). Interestingly, just one fluorophore, Ru(bpy)3 2+, sufficed to discriminate between 16 samples of whiskies (Scotch, Irish, Bourbon, and other varieties). The quality of discrimination by RGB images was at least equal to that obtained using the emission spectra measured with a spectrofluorimeter (400–700 nm). Using any of the studied fluorophores is more efficient for discrimination than depending on the intrinsic fluorescence of individual whiskies.
关键词： Fluorophore,Whisky,Tris(2,2′?bipyridyl)dichlororuthenium(II),Principal component analysis,Fluorescent fingerprints,Digital image,Contrasting,Discrimination
更新于2025-09-23 15:21:01
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A Polymerizable Photoswitchable Fluorophore for Super-Resolution Imaging of Polymer Self-Assembly and Dynamics
摘要： Single-molecule super-resolution microscopy has become a standard imaging tool in the life sciences for visualizing nanostructures in situ, but the application of this technique in polymer science is much less explored. A key bottleneck is the lack of fluorophores and simple covalent attachment strategies onto polymer chains. Here, we report a functional diarylethene-based photoswitchable fluorophore that can be directly incorporated into polymer backbones through copolymerization, which significantly streamlines the labeling strategy, with no further postcoupling reactions or purifications needed. The attachment of fluorophores onto selectively labeled polymers enables super-resolution imaging of a series of model polymer blend systems with different nanostructures and chemical compositions. As each individual fluorophore is able to switch several times on average between its bright and dark state, multiple time-lapse images can be acquired to observe the dynamic nanostructural evolution of polymer blends upon solvent vapor annealing. With this demonstration of a universal, simplified labeling strategy and the ability to image polymer assembly under native conditions, this reported fluorophore may promote the widespread use of super-resolution microscopy in the polymer community.
关键词： diarylethene,polymer dynamics,super-resolution microscopy,photoswitchable fluorophore,polymer self-assembly
更新于2025-09-23 15:21:01
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Fluorescent Sensors Based on a Novel Functional Design: Combination of an Environment-sensitive Fluorophore with Polymeric and Self-assembled Architectures
摘要： The fluorescence properties, e.g., fluorescence intensity, of fluorescent sensors can change due to covalent derivatization or noncovalent complexation with a target chemical species (i.e., molecules and ions) or by variations in circumstantial physical parameters (e.g., temperature and viscosity). The internal charge transfer (ICT) character and photoinduced electron transfer (PET) efficiency can be used to tune the fluorescence switching mechanism, facilitating the development of new fluorescent sensors. In addition, the utilization of an environment─ sensitive (i.e., polarity─ and hydrogen bonding─ sensitive) fluorophore in stimulus─ responsive macromolecules to design novel fluorescent sensors has been proposed. Based on this concept, highly sensitive fluorescent polymeric thermometers and (extremely sensitive) digital fluorescent pH sensors have been developed. These thermometers are being used to measure the temperature of live cells in biological and medical studies. This concept has also allowed nanoscale proton mapping near membranes, which exemplifies the downsizing of targets for fluorescent sensing from a micrometer─ scale to a nanometer─ scale.
关键词： digital fluorescent pH sensors,polymeric thermometers,nanoscale proton mapping,fluorescent sensors,environment─ sensitive fluorophore
更新于2025-09-23 15:19:57
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Fluorescence-Guided Neurosurgery (Neuro-oncology and Cerebrovascular Applications) || 1 Current Fluorescence-Guided Neurosurgery and Moving Forward
摘要： This introductory chapter provides a current overview of fluorescence-guided neurosurgery and includes future directions. The concepts of fluorescence and fluorescence-guided surgery (FGS) are introduced. Currently used fluorescent contrast agents in patients are summarized, including 5-aminolevulinic acid (5-ALA), fluorescein, and indocyanine green. Excitation light sources are discussed for each fluorescent contrast agent. Targeted fluorophores under clinical development for FGS are also introduced. Future directions in fluorescence-guided neurosurgery including handheld devices to better detect tumor fluorescence, dual fluorophore imaging, metabolic imaging in combination with FGS, and detection of the tumor margin will be discussed.
关键词： near-infrared imaging,fluorophore,indocyanine green,fluorescence-guided neurosurgery,fluorescence,operative microscope,fluorescence-guided surgery,fluorescein sodium,5-ALA
更新于2025-09-19 17:15:36
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Plasmonic Electricity: Fluorophore-Induced Plasmonic Current
摘要： Fluorophore-induced plasmonic current is generated when an excited fluorophore in close proximity to a metal nanoparticle film non-radiatively transfers energy to the metal, resulting in an electrical current across the film. Although a growing literature reports the use of surface plasmons for fluorescence enhancement as well as plasmons for current generation, little has been published hitherto regarding the electrical current generation via the fluorophore excitation of plasmons. Our “plasmon to current” technique utilizes electron transport between closely spaced metal nanoparticles, generating a measureable electrical signal upon excitation of a proximal fluorophore. This induced electrical signal is found to be strongly dependent on the magnitude of the fluorophore extinction coefficient. In other words the electrical signal contains photophysical information pertaining to the fluorophore, potentially leading to the direct detection of fluorescence without the need for traditional detectors such as photomultiplier tubes and charge coupled devices. In addition, we demonstrate the dependence of this current on fluorophore concentration and excitation laser polarization. Fluorophore-induced plasmonic current holds potential as a novel molecular detection platform with simplified instrumentation, compatible with a variety of fluorescent probes.
关键词： Plasmonics,Fluorophore-Induced Plasmonic Current,Hybrid Materials,Magnetic,Optical
更新于2025-09-19 17:13:59
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Rapid, facile, reagentless, and room-temperature conjugation of monolayer MoS2 nanosheets with dual-fluorophore-labled flares as Nanoprobes for ratiometric sensing of TK1 mRNA in living cells
摘要： Direct loading of fluorophore-labeled DNA molecules (named as flares) on gold nanoparticles (AuNPs) is a controllable and straightforward approach for intracellular imaging of target DNA molecules. However, the modification of AuNPs with flares requires a tedious and time-consuming procedure, additional reagents, or adenosine-rich DNA molecules. Here, we developed a rapid, simple, reagentless, and room-temperature approach for the modification of monolayer molybdenum disulfide nanosheets (M-MoS2 NSs) with dual-fluorophore-labeled flares, which were implemented for ratiometric imaging of TK1 mRNA in living cells. The duplexes were prepared by hybridizing thiolated single-stranded DNA (ssDNA) to 6-carboxyfluorescein (FAM)- and 5-carboxytetramethylrhodamine (TAMRA)-labeled flares. Fabrication of the nanoflares was conducted by conjugating the formed duplexes to the surface sulfur vacancy sites of the M-MoS2 NSs. The time for preparing the nanoflares was found to be completed within 1 h. In the nanoflares, FAM stays away from TAMRA, leading to inefficient fluorescence resonance energy transfer (FRET). The presence of perfectly matched DNA (DNApm) molecules induces the liberation of the flares from the nanoflares. The liberated flares fold into hairpin-shaped structures, causing high FRET efficiency from FAM to TAMRA and efficient FAM-TAMRA static quenching. Following this mechanism, the nanoflares provided an effective platform for ratiometric sensing of DNApm molecules with the limit of detection (at a signal-to-noise ratio of 3) of 8 nM and the linear range of 25?500 nM. Confocal microscopy experiments demonstrated that the nanoflares can be used to ratiometrically image TK1 mRNA in HeLa and MCF-7 cells.
关键词： ratiometric sensing,monolayer MoS2 nanosheets,TK1 mRNA,dual-fluorophore-labeled flares,living cells
更新于2025-09-16 10:30:52
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Flexible Luminescent Organic Bulk Crystal: 2D Elasticity toward 3D Optical Waveguide
摘要： The study of elastic organic single crystals becomes a hot research field in the crystal engineering, and elastic bending of needle-like crystals has been carefully investigated recently. Herein, based on a structurally simple molecule dimethyl 2,5-diaminoterephthalate (DMDAT), the organic crystals which display not only elastic bending ability but also elastic twisting ability under applied stress are reported. These ribbon-like DMDAT crystals are fully flexible and can be freely bended and twisted, thus forming any 3D conformation. Moreover, the unique X-shaped tetrasubstituted benzene structure enables DMDAT crystals to display efficient yellow emission based on a very small π-system. Taking these advantages, 3D optical waveguide is successfully realized in the DMDAT crystal with a highly twisted 3D belt-shaped structure, demonstrating the ultimate 3D application of flexible organic bulk crystals.
关键词： fluorophore,optical waveguide,flexible crystal,organic crystal
更新于2025-09-11 14:15:04
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Fluorometric determination of aflatoxin B1 using a labeled aptamer and gold nanoparticles modified with a complementary sequence acting as a quencher
摘要： A fluorometric aptamer based assay is described for rapid and sensitive detection of aflatoxin B1 (AFB1). It is making use of a fluorescein (FAM) labeled anti-AFB1 aptamer and complementary DNA-modified gold nanoparticles (GNPs). In the absence of AFB1, the FAM-labeled aptamers hybridize with complementary DNA strands that were covalently immobilized on GNPs. This results in quenching of the green fluorescence (with excitation/emission peaks at 485/525 nm). In the presence of AFB1, the aptamer probe binds AFB1 and is released from the GNPs. Hence, fluorescence is restored. Under optimized conditions, AFB1 in the concentration range from 61 pM to 4.0 μM can be detected, and the detection limit is 61 pM. This assay is highly selective for AFB1. It was applied to the determination of AFB1 spiked into 50-fold diluted wine and 20-fold diluted beer.
关键词： Mycotoxin,Food safety,Environmental analysis,Fluorescence quenching,Fluorophore,Fluorescent probe,Nanomaterials,Nanoprobe
更新于2025-09-11 14:15:04
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Novel Dicyano-Phenylenevinylene Fluorophores for Low-Doped Layers: A Highly Emissive Material for Red OLEDs
摘要： Two efficient deep red (DR)-emitting organic dicyano-phenylenevinylene derivatives with terminal withdrawing or donor groups were synthesized. The spectroscopic properties of the neat solids and the low-doped layers in polystyrene or polyvinylcarbazole host matrixes were analyzed, and the luminescence performance was explained using density functional theory (DFT) analysis. A noteworthy 89% fluorescence quantum yield was observed for the brightest red-emissive polyvinylcarbazole (PVK) blend. This result pushed us to successfully produce an emissive red organic light-emitting device (OLED) as a preliminary feasibility test.
关键词： dicyano-phenylenevinylene,fluorophore,aggregation-caused quenching (ACQ),OLED,DR
更新于2025-09-11 14:15:04