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A red-emitting fluorescent probe with large Stokes shift for real-time tracking of cysteine over glutathione and homocysteine in living cells
摘要： Fluorescent probes with high quality for highly selective detection of cysteine (Cys) are still urgently in demand because of the indispensable roles Cys plays in the biological systems. Herein, a red-emitting fluorescent probe CP was developed for the highly selective detection of Cys over glutathione (GSH) and homocysteine (Hcy) by incorporating the recognition unit into the 2-(2-(4-hydroxystyryl)-6-methyl-4H-pyran-4-ylidene) malononitrile (P-OH) fluorophore which is characterized by red emission, noteworthy Stokes shift, and appreciable photostability. Basically, CP demonstrated appreciable sensing performance toward Cys including short response time of 4 min, high sensitivity with approximately 147-fold emission enhancement, low detection limit of 41.696 nM, and good selectivity both in the solution and living cells, indicating its promising potential of visualizing Cys in biological systems.
关键词： Large Stokes shift,Fluorescence imaging,Cysteine detection,Fluorescent probe
更新于2025-11-19 16:56:35
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Novel BODIPY-based fluorescent probes with large Stokes shift for imaging hydrogen sulfide
摘要： Hydrogen sulfide has important biomedical significance because it plays a regulatory role in a variety of physiological processes. In our previous work, we investigated the effect of substituents on Stokes shift of BODIPY and found that methoxy groups on phenyl substituents at 3,5-positions could expand the Stokes shift of BODIPY-based probes. In this study, taking hydrogen sulfide (H2S) as analyte, we designed and synthesized 4,4-difluoro-8-{4-(2,4-dinitrophenoxy)phenyl}-3,5-bis(2,4-dimethoxyphenyl)-4-bora-3a,4a-diaza-s-indancene (DMOEPB) and 4,4-difluoro-8-(4-nitrophenyl)-3,5-bis(2,4-dimethoxyphenyl)-4-bora-3a,4a-diaza-s-indancene (DMONPB) according to the same strategy. As expected, Stokes shifts of 49 nm and 51 nm were obtained respectively, which demonstrate the feasibility of the strategy in the synthesis of other fluorescent probes for the detection of small biomolecules. DMONPB can react with H2S to form the derivative with a fluorescence quantum yield of 0.13. An excellent linear relationship was observed in the range of H2S concentrations from 0 μM to 800 μM and the detection limit was 1.3 μM. Furthermore, it can be successfully applied to imaging of H2S in cells and tissues. For DMOEPB, the presence of m-dinitrophenyl did not cause the expected fluorescence quenching, which makes it impossible to perform bioimaging. We speculate that the strong electron-withdrawing property of nitro group is obviously weaker when the two benzene rings are separated at 8-position and are not conjugated with the fluorophore. It provides experience and lessons for designing the same type of turn-on probe.
关键词： hydrogen sulfide,BODIPY,red fluorescence,bioimaging,large Stokes shift
更新于2025-11-19 16:46:39
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A near-infrared fluorescence probe for ultrafast and selective detection of peroxynitrite with large Stokes shift in inflamed mouse models
摘要： Peroxynitrite (ONOO?) is a kind of reactive oxygen species (ROS) which is associated with pathogenesis of many diseases. A new near-infrared fluorescence probe (DCM-OH) which based on dicyanomethylene-4H-pyrans to detect endogenous ONOO? was designed and synthesized. The two-photon absorption cross sections and large Stokes shift make the probe deeper issue penetration and lower self-absorption. The obtained results demonstrated that probe DCM-OH could sensitively detect ONOO? with a low detection limit (53 nM). What’s more, probe DCM-OH exhibited an ultrafast response rate (within 5 s) toward ONOO?, which would be in favor of tracking the highly reactive and short-lived ONOO? in the living systems. Moreover, DCM-OH was successfully employed for imaging endogenous ONOO? in HepG2/RAW 264.7 cells and further applied to visualize oxidative stress in mouse model of inflammation.
关键词： In vivo imaging,NIR,Fluorescence probe,Peroxynitrite,Large Stokes shift
更新于2025-11-14 15:29:11
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NIR-Fluorescent Multidye Silica Nanoparticles with Large Stokes Shifts for Versatile Biosensing Applications
摘要： We have synthesized and characterized of a series of single and multidye copolymerized nanoparticles with large to very large Stokes shifts (100 to 255 nm) for versatile applications as standalone or multiplexed probes in biological matrices. Nanoparticles were prepared via the St?ber method and covalently copolymerized with various combinations of three dyes, including one novel aminocyanine dye. Covalently encapsulated dyes exhibited no significant leakage from the nanoparticle matrix after more than 200 days of storage in ethanol. Across multiple batches of nanoparticles with varying dye content, the average yields and average radii were found to be highly reproducible. Furthermore, the batch to batch variability in the relative amounts of dye incorporated was small (relative standard deviations <2.3%). Quantum yields of dye copolymerized nanoparticles were increased 50% to 1000% relative to those of their respective dye-silane conjugates, and fluorescence intensities were enhanced by approximately three orders of magnitude. Prepared nanoparticles were surface modified with polyethylene glycol and biotin and bound to streptavidin microspheres as a proof of concept. Under single wavelength excitation, microsphere-bound nanoparticles displayed readily distinguishable fluorescence signals at three different emission wavelengths, indicating their potential applications to multicolor sensing. Furthermore, nanoparticles modified with polyethylene glycol and biotin demonstrated hematoprotective qualities and reduced nonspecific binding of serum proteins, indicating their potential suitability to in vivo imaging applications.
关键词： Fluorescent silica nanoparticles,Biocompatible nanoparticles,Large stokes shift,Near-infrared fluorescence,Multicolor assay,Resonance energy transfer
更新于2025-09-23 15:23:52
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Orange-red fluorescent polymer nanocomposite films with large stokes shift: An opto-electronic exercise
摘要： Herein, we report the successful fabrication of orange-red fluorescent polymer nanocomposite (PNC) hybrids, that envisage efficient photon management and appreciable UVA-protection, besides high design flexibilities and ease of self-cleaning. The visibly transparent PNC thick films were developed via aqueous solution casting of -OH backboned poly (vinyl alcohol) (PVA) with nanostructured sodium zincate (Na2ZnO2). The as developed PNC films offer appreciable photonic down-conversion of high energy UVA-radiations to relatively lower energy Orange-red light via fluorescent emission. The optical band gap studies reveal a direct band gap relationship with valence band maxima and conduction band minima occurring at same wave vectors. While, static contact angle measurements support nanofiller induced wettability transitions (hydrophilic to near hydrophilic). The fluorescence spectral (excitation and emission) studies of PVA/Na2ZnO2 NC films validate a promisingly large Stokes shift (~245 nm), which visualises a fair separation between the photonic absorption and emission bands, that may further aid an exponential minimization of optical losses due to re-absorption. The thermogravimetric studies support their excellent thermal stabilities. The relatively large Stokes shift, appreciable thermal stability and excellent UV harvesting ability of PVA/Na2ZnO2NC films construct them as competent luminescent down-shifting (LDS) materials for possible solar cell applications.
关键词： Orange-red fluorescence,Stokes shift,Opto-electronics
更新于2025-09-23 15:23:52
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Bright red-emitting highly reliable styryl probe with large stokes shift for visualizing mitochondria in live cells under wash-free conditions
摘要： Bright red-emitting pyridinium cyanine based styryl probe 2 is synthesized in good yields. Probe 2 demonstrated a large Stokes’ shift (Δλ ≈ 128 nm, 4227 cm-1 in DCM) and excellent fluorescent quantum yield (?fl ≈ 0.2 - 0.7) due to strong Intra-molecular charge transfer (ICT). Probe 2 found to exhibit exceptional selectivity for cellular mitochondria in both normal (COS-7) and cancer (A549) cell lines. Probe 2 is readily applicable as a “wash-free” dye to visualize mitochondria as it does not require post-staining washing prior to imaging. Styryl probe 2 also showed an excellent biocompatibility as the calculated LC50 (lethal concentration, 50%) value was > 20 μM. Probe 2 emission did not show any interferences from anionic species or other biological molecules. Probe 2 is readily excitable (λex ~460 and λem ~618 nm) with the available laser (454 nm) in commercial microscopes and thus it can be a useful probe for mitochondrial tracking in live cells.
关键词： Wash-free application,Biocompatibility,Intra-molecular charge transfer (ICT),Styryl dye,Large Stokes shift,Mitochondria selectivity
更新于2025-09-23 15:23:52
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A novel NIR-emissive probe with large Stokes shift for hypochlorite detection and imaging in living cells
摘要： Due to the importance of hypochlorite (ClO-) in the process of life, a near-infrared region (NIR) emissive probe (DCPO-DMTC) with large Stokes shift was synthesized for the selective detection of hypochlorite. This probe detects exogenous and endogenous hypochlorite via "oxidative deprotection" of dimethylthiocarbamate-protected phenolic hydroxyl groups. The response was monitored by time-course UV–Vis and fluorescent spectroscopy. The emission response of the probe to ClO? presented a good linear relationship in the 0–100 μM concentration range, and the LOD of this probe was 164 nM. The probe was used to successfully visualize endogenous ClO- generation in RAW 246.7 cells under external stimulation.
关键词： NIR-emissive,Large Stokes-shift,Hypochlorite,Bioimaging
更新于2025-09-23 15:22:29
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Counter Anion Effect on the Photophysical Properties of Emissive Indolizine-Cyanine Dyes in Solution and Solid State
摘要： Near-infrared emissive materials with tunable Stokes shifts and solid-state emissions are needed for several active research areas and applications. To aid in addressing this need, a series of indolizine-cyanine compounds varying only the anions based on size, dipole, and hydrophilicity were prepared. The effect of the non-covalently bound anions on the absorption and emission properties of identical π-system indolizine-cyanine compounds were measured in solution and as thin films. Interestingly, the anion choice has a significant influence on the Stokes shift and molar absorptivities of the dyes in solution. In the solid-state, the anion choice was found to have an effect on the formation of aggregate states with higher energy absorptions than the parent monomer compound. The dyes were found to be emissive in the NIR region, with emissions peaking at near 900 nm for specific solvent and anion selections.
关键词： solid-state emission,optical materials,NIR emissive materials,indolizine cyanine,stokes shift
更新于2025-09-23 15:22:29
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Solvent effects on the absorption and fluorescence spectra of Zaleplon: Determination of ground and excited state dipole moments
摘要： Solvent effects on the absorption and fluorescence spectra of Zaleplon, a nonbenzodiazepine sedative/hypnotic drug that is mainly used for the short term treatment of insomnia, were investigated in 18 different solvents with diverse polarities. Dipole moments of the ground and excited state (μg and μe) were determined by Lippert–Mataga, Bakhshiev, Reichardt, McRae and Suppan solvatochromic methods. The dipole moment of Zaleplon ground state in the gas phase has been calculated as μg = 10.95 D (TD-DFT) with B3LYP/cc-pVTZ functional. There is a good agreement of theoretical data with Reichardt, McRae, and Suppan correlations, while some dissidence with Lippert–Mataga and Bakhshiev equations is suggesting the occurrence of specific solute–solvent interactions. Additionally, multiple linear regression analyses with Kamlet–Taft and Catalan solvatochromic models was applied to solute–solvent interactions. Dominant property of the solvent that affects the absorption band and Stokes shifts of Zaleplon is polarity of the solvent while the emission band is influenced mainly by solvent basicity.
关键词： Solvatochromic methods,Dipole moment,Stokes shift,MLR analysis,Zaleplon
更新于2025-09-23 15:22:29
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Impact of Stokes Shift on the Performance of Near-Infrared Harvesting Transparent Luminescent Solar Concentrators
摘要： Visibly transparent luminescent solar concentrators (TLSC) have the potential to turn existing infrastructures into net-zero-energy buildings. However, the reabsorption loss currently limits the device performance and scalability. This loss is typically defined by the Stokes shift between the absorption and emission spectra of luminophores. In this work, the Stokes shifts (SS) of near-infrared selective-harvesting cyanines are altered by substitution of the central methine carbon with dialkylamines. We demonstrate varying SS with values over 80 nm and ideal infrared-visible absorption cutoffs. The corresponding TLSC with such modification shows a power conversion efficiency (PCE) of 0.4% for a >25 cm2 device area with excellent visible transparency >80% and up to 0.6% PCE over smaller areas. However, experiments and simulations show that it is not the Stokes shift that is critical, but the total degree of overlap that depends on the shape of the absorption tails. We show with a series of SS-modulated cyanine dyes that the SS is not necessarily correlated to improvements in performance or scalability. Accordingly, we define a new parameter, the overlap integral, to sensitively correlate reabsorption losses in any LSC. In deriving this parameter, new approaches to improve the scalability and performance are discussed to fully optimize TLSC designs to enhance commercialization efforts.
关键词： transparent luminescent solar concentrators,overlap integral,reabsorption loss,Stokes shift,near-infrared harvesting
更新于2025-09-23 15:21:01