Journal of Fluorescence最新文献

Dicyanoisophorone-based fluorophores (DF) hold broad application prospects in the fields of fluorescent probes and biomedicine. However, the structure-activity relationship (SAR) of these fluorophores following the introduction of different substituents at distinct sites remains unclear, which limits their further application and performance optimization. In this study, we systematically investigated the effects of introducing electron-donating groups (Me, OMe, NH₂, NMe₂ and NPh₂) and electron-withdrawing groups (F, NO₂, COOH, CN and SO₃H) at the C3, C4, and C6 sites of the benzene ring on the structure and properties of DF from a theoretical perspective, thereby providing a theoretical basis and reference for the subsequent modification and improvement of this class of fluorescent probes.

Hydrogen sulfide (H₂S) functions as a critical gaseous signaling molecule, and dysregulated levels are linked to various pathological conditions, such as diabetes, cardiovascular disorders, Alzheimer's disease, and malignant tumors. To facilitate disease monitoring and improve the understanding of related mechanisms, it is imperative to establish a rapid and precise method for detecting H₂S. In this work, we have designed a new near-infrared fluorescent probe, designated TPA-YL, for H₂S sensing. TPA-YL probe utilizes triphenylamine thiophene dye as a fluorophore, and 2,4-dinitrobenzenesulfonyl (DNS) as the response site for H₂S. In the presence of H₂S, the responsive group in TPA-YL undergoes thiolysis, and near-infrared fluorescence from the fluorophore is "turned on". The resulting fluorescence signal exhibits a good linear relationship with H₂S up to 50 µM (limit of detection, 17 nM). The advantages of TPA-YL include: a long emission wavelength (642 nm); a large Stokes shift (188 nm); high selectivity; as well as remarkable sensitivity (under physiological conditions). Furthermore, the TPA-YL probe has been effectively applied for visualizing both externally supplied and internally generated H₂S in HeLa cells via fluorescence imaging. Thus, this probe provides a promising strategy for studying the role of H₂S in intricate physiological and pathological mechanisms. We develop a novel near-infrared fluorescent probe (TPA-YL) for the detection of H₂S. In the presence of H₂S, the responsive group in TPA-YL undergoes thiolysis, and near-infrared fluorescence from the fluorophore is "turned on". TPA-YL enables H₂S detection in both in vitro and in vivo settings.

In this work, we report the green synthesis of fluorescent carbon dots (MS-CDs) from Mammea suriga leaves via a simple and efficient probe for environmental detoxification. The synthesized MS-CDs were spectroscopically characterized by UV-Vis spectroscopy, fluorescence spectroscopy, FTIR, HR-TEM, X-ray diffraction, and ¹³C NMR spectroscopy. The particle sizes were found to be in the range of 2.2-4.6 nm. FTIR analysis confirmed the presence of -OH functional groups, and XRD studies confirmed the amorphous nature of the MS-CDs. The synthesized MS-CDs were used as a photocatalyst in the degradation of Eosin B, exhibiting 90% and 68% degradation activity at pH 6 and pH 9, respectively, within 240 min. Furthermore, the biological studies reflected that the MS-CDs are a promising scaffold owing to their excellent antioxidant and anti-inflammatory properties with IC₅₀ values as 42.92 ± 0.92 and 34.00 ± 0.98 µg/mL respectively. Additionally, MS-CDS exhibited significant antidiabetic potency with IC₅₀ value as 33.57 ± 0.73 and 25.78 ± 0.51 µg/mL for α-amylase and α-glucosidase inhibition, respectively. This study highlights MS-CDs as promising dual-function materials, combining efficient photocatalytic performance with potent biological activities.

Hypochlorous acid (HOCl) is a reactive oxygen species involved in both host defense and pathological processes, making its detection in biological systems of critical importance. Herein, we report the design and synthesis of a phenazine-based fluorescent probe, PNN, incorporating an imidazoline-2-thione recognition unit for selective HOCl detection. PNN exhibits a distinct "turn-on" fluorescence at 555 nm upon reaction with HOCl, with an enhancement of approximately 108-fold, surpassing that of previously reported thione-based probes, which typically emit in the 445-505 nm range. PNN also shows high sensitivity, rapid response, and excellent selectivity over other reactive oxygen and nitrogen species. Furthermore, PNN displays negligible cytotoxicity in HeLa cells and enables concentration-dependent visualization of exogenous HOCl in living cells. These features position PNN as a robust and reliable tool for monitoring HOCl in complex biological environments, providing a versatile platform for investigating its physiological and pathological functions.

Schiff base tethered 1,2,3-triazole (TBT) having excellent optical properties were examined via fluorescence and UV-vis spectroscopy that revealed it to be a highly selective and sensitive Lead and Copper ions sensor. TBT exhibited colorimetric changes for the Cu²⁺ and Pb²⁺ ions in the solution form. The probe TBT exhibited ultra-low detection limit of 190 pM and 130 pM for the Cu²⁺ and Pb²⁺ ions respectively. The Job's plot analysis confirmed the 1:1 stoichiometry of TBT-Cu²⁺ and TBT-Pb²⁺ complexes and time dependent, pH titration, and the reversibility, mimicking INHIBIT logic gate, were also explored photo-physically. Moreover, TBT-Cu(II) and TBT-Pb(II) complexes were studied via DFT studies at the B3LYP/6-311G++(d, p)/LANL2DZ depicting their binding interactions that supplemented with their experimental FTIR and mass analysis. Furthermore, the practical utility of sensor TBT was validated in real water samples with exclusive Pb(II) and Cu(II) ions detection imminent potential in environmental and analytical applications.

The liquid-assisted grinding method synthesizes six novel europium complexes with "6-fluoro-7-piperazinyl-4-quinoline" (L) and heterocyclic ancillary ligands. This synthesis method is eco-friendly and less time-consuming. The prepared complexes were characterised by various spectroscopic techniques CHN analysis IR, UV-Vis, XRD, EDAX and SEM. IR and NMR spectroscopic techniques indicate the mode of coordination of the ligand and ancillary ligand with metal ions. UV-vis absorption and reflectance spectra of the all complexes give information about the optical properties and Urbach energy of the complexes. Photoluminescent properties in powder and solution state suggest that the complexes show ruby red emission under UV radiation. The ⁵D₀ →⁷F₂ transition is responsible for emitting ruby red color. The intensity of europium transitions increases with the introduction of an ancillary ligand along with L. Judd Ofelt parameter is also vital to define the symmetry of lanthanide coordination environment and lanthanide-ligand bond's nature in the complexes. The LUMPAC software also validates the JO parameters. Color purity and the CCT (correlated colour temperature) values indicate that the complexes with high color purity, warm red-light sources, are used in the illuminating OLEDs. The thermal stability of complexes is investigated by thermogravimetric analysis and temperature-dependent photoluminescence. The branching ratio and lasing aspect were also precisely derived. As a result of all characterisation, these complexes are used in photoluminescent and optoelectronic devices. Complexes are a strong contender for the antimicrobial and antioxidant agent because they have good biological properties.

The hydrazide functional group is known for its specific recognition of peroxynitrite. Upon incorporation into rhodamine fluorophores, the resulting fluorescent probes have been widely used for the real-time tracking of peroxynitrite in biological systems. However, the lack of in-depth research on the fundamental reaction mechanism in peroxynitrite detection has limited the optimization of these probes. In this study, we developed two hydrazide-based peroxynitrite probes by linking hydrazine moiety to rhodamine and thio-rhodamine. The responsiveness of these probes toward peroxynitrite was also systematically investigated. Theoretical calculations indicate that the key mechanism of hydrazide-based probes in peroxynitrite detection lies in the reduced Gibbs free energy difference between the ring-open and ring-closed isomers of the oxidized intermediate, which thereby facilitates the ring-opening process. Overall, this study elucidates the reaction mechanism of hydrazide-based peroxynitrite probes from the perspective of Gibbs free energy, providing valuable insights for the rational design and optimization of rhodamine ring-opening probes.

In this work, we report the synthesis and characterisation of holmium-doped lanthanum indium oxide as a promising luminescent material for biomedical applications. Samples were prepared via the Pechini sol-gel method and structurally confirmed to crystallise in an orthorhombic perovskite phase (Pnma), with minor In₂O₃ impurities. Morphological analysis revealed irregular micrometric agglomerates with homogeneous elemental distribution. Optical studies demonstrated efficient absorption at 890 nm (the first biological window) and emission centred at ~ 1200 nm (the second biological window), attributed to the ⁵I₆ → ⁵I₈ transition of Ho³⁺. The sample doped with 1.0 mol% Ho³⁺ exhibited the highest emission intensity. Luminescence tests confirmed detectable luminescence through up to 4 mm of blood, highlighting the material's potential for deep-tissue imaging. These results position LaInO₃:Ho³⁺ as a viable candidate for infrared bioimaging working in the first and the second biological windows simultaneously.

In this study, a Zinc oxide/Tin dioxide/Carbon quantum dots nanocomposite (ZnO/SnO₂/CQDs NCPs) was successfully synthesized and comprehensively characterized, and its application as a photoluminescence-based sensor for highly sensitive uric acid detection was explored. Individual nanoparticles of CQDs, ZnO, and SnO₂ were synthesized via a hydrothermal method, while the final composite was fabricated through a straightforward physical mixing approach. Characterization results obtained from UV-vis spectroscopy, XRD, TEM, and EDX analyses confirmed the structural integrity, morphology, and improved surface properties of the as-prepared nanocomposite. TEM images revealed that SnO₂ nanoparticles possessed an average diameter of ≈ 3 nm, ZnO nanoparticles ≈ 50 nm, and CQDs ≈ 22 nm, with ZnO, SnO₂, and CQDs randomly interconnected within the ZnO/SnO₂/CQDs nanocomposites (ZnO/SnO₂/CQDs NCPs). The sensing mechanism was governed by the "turn-on" photoluminescence phenomenon, arising from electron transfer between the excited nanocomposite and uric acid molecules. The fabricated sensor exhibited outstanding analytical performance, including an ultra-low limit of detection (LOD) of 0.085 nM, an exceptionally wide linear detection range spanning from 10^-13 M to 0.1 M, and a strong linear correlation coefficient (R² = 0.992) at the excitation wavelength of 420 nm, attributed to the synergistic interactions among the components. These findings underscore the composite's potential as a highly sensitive and reliable platform for uric acid detection. This work thus provides a simple, cost-effective, and promising strategy for clinical diagnostics and broader biomedical applications.