Journal of Fluorescence最新文献

In this study, a novel fluorescent "turn-on" probe, (E)-N'-(2-(2-hydroxynaphthalen-1-yl) ethylidene)-2,5-diphenyl-2 H-1,2,3-triazole-4-carbohydrazide (G₄), was designed and synthesized, and fully characterized by various analytical techniques. Spectroscopic investigations revealed that G₄ exhibits excellent selectivity and sensitivity toward Al³⁺, with a 1:1 binding stoichiometry and a detection limit of 1.623 nM. Its advantages over existing probes include the lower detection limit and a distinct color reaction under UV light, which facilitates straightforward qualitative detection with lower cytotoxicity. The sensing mechanism was elucidated through density functional theory (DFT) and quantum chemical calculations. Then the practical utility of G₄ was demonstrated through recovery experiments in real water samples and its development into a portable test kit. Furthermore, cell experiments and zebrafish imaging confirmed its biocompatibility and applicability in biological systems with lower cytotoxicity. As a candidate drug that may be developed and utilized, the interactions of G₄ with two serum proteins (HSA and HIgG) were also investigated through spectrofluorometric and molecular docking analysis, revealing hydrogen bond or van der Waals forces as the main mode of action, suggesting potential for further biomedical applications. These results highlight G₄ as a highly sensitive, selective, and dual-functional fluorescent probe with significant potential for environmental monitoring and biological sensing.

The development of highly selective and sensitive fluorescent chemosensors is urgently needed to detect toxic aluminum ions (Al³⁺) ions in environmental and biological systems. This work presents the development of a novel Schiff-base fluorescent probe L, which was efficiently synthesized via a one-pot condensation reaction between 3,5-di-tert-butylsalicylaldehyde and 4,5-dimethyl-1,2-phenylenediamine. The molecular structure of the probe L was characterized using nuclear magnetic resonance spectroscopy (¹H/¹³CNMR) and infrared spectroscopy (FT-IR). Fluorescence spectroscopy studies have shown that probe L exhibits specific recognition of Al³⁺ in ethanol/PBS solutions. After adding Al³⁺, the fluorescence at 547 nm is significantly enhanced, displaying a bright green fluorescence under 365 nm ultraviolet light, and it is not interfered with by other metal ions such as Na⁺, K⁺, Ca²⁺, Mg²⁺, Fe³⁺, Cu²⁺, and Zn²⁺. Job's plot and theoretical calculations confirm that probe L forms a 1:1 complex with Al³⁺, with a binding constant (K_a) of 2.64 × 10⁴ ± 44.67 M^- 1, and a detection limit (LOD) as low as 1.19 µM. This probe maintains stable recognition performance under a wide range of environmental conditions and has significant potential applications in environmental monitoring.

Mitochondrial membrane potential (MMP) is a key indicator of mitochondrial function and cellular health. Fluorescence intensity-based methods are widely used for MMP monitoring, where probe photostability is critical for accurate quantification. To improve imaging reliability, we developed a photostable mitochondrial-targeted probe, PDI-TPP, by linking perylene diimide (PDI) with triphenylphosphonium (TPP). To the best of our knowledge, this is the first report of PDI being rationally designed and synthesized as a FRET donor for MMP sensing. Acting as a FRET donor, PDI-TPP pairs with SiR-BA, which is synthesized by conjugating silicon-rhodamine with butyric acid, to achieve dual-modality imaging through both fluorescence intensity ratio and lifetime. Compared to our previous donor OR-C8, PDI-TPP shows significantly enhanced photostability, reducing photobleaching artifacts and enabling dynamic visualization of MMP changes. This work provides a more accurate tool for mitochondrial imaging and functional studies.

The exploitation of an extremely sensitive and reliable nanozyme based colorimetric sensor for highly sensitive detection of hydrogen peroxide (H₂O₂) in living body system is extensively carping owing to fact that it garnered a prime role in causing toxic diseases. In this work, a highly novel catalyst named as Cerium oxide (CeO₂) nanosheets (NSs) was precisely prepared by using a simple one pot hydrothermal method, thereby dowered with a strong intrinsic peroxidase like capability of catalyzing the oxidation-reaction of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to generate a blue color reaction in the presence of H₂O₂. Hence, a sensitive visible assessment platform related to CeO₂ NSs was engineered, which not only exhibited a wider detection range of 0.01-1000 µM with R² value of 0.9998, but also perceives exceptional selectivity, tremendous cycling and long term stability. Further, the sensor also evaluates lowest detection limit (LOD) 0.29 ± 0.03 µM and quantification limit (LOQ) of 2.3 ± 0.03 µM. In addition, it also endorses impressive practicality with stronger sensitivity and favorable accuracy in serum samples. Thus, this research-work not only contributed upon CeO₂ NSs an outstanding capacity to detect H₂O₂, but also expands the realm of applications for CeO₂ NSs in the domains of environmental preservation, biomedical diagnosis and forensic sciences.

Four rare-earth complexes were prepared using Eu³⁺ and Tb³⁺ as central rare-earth ions and benzoic acid, furoic acid, α-thenoyltrifluoroacetone, and phenanthroline as organic ligands, and a four-channel fluorescent sensor array was constructed for the identification of triphenylmethane drugs. The four sensing units have different degrees of fluorescence response to six triphenylmethane drugs. The fluorescence quenching of Eu(III) complex by malachite green and Tb(III) complex by methyl violet were confirmed to be the FRET effect. After five parallel experiments, a 4 × 6 × 5 fluorescence data matrix was obtained, and the linear discriminant method were used to distinguish six triphenylmethane drugs at 0.1, 1.0, and 10 µmol L⁻¹ and mixed triphenylmethane drugs at 1.0 µmol L⁻¹ with an accuracy rate of 100%. The array achieved the identification of triphenylmethane drugs in fish samples with accuracy rate of 97.4%.

This study emphasises the Synthesis of novel bis-Schiff base derivatives via the condensation reaction of two different aldehydes with a aromatic diamine. This reaction was carried out between p-phenylenediamine with 4-chlorobenzaldehyde and 2,4-dichlorobenzaldehyde. The study will explain the structural comparison between the compound PP4CLB and PP24CLB. The synthetic compounds' configurations were verified by DFT calculations, and their structural integrity was verified by NMR, Raman, and IR spectroscopy. To provide a detailed characterisation of molecular properties, the study included a wide range of analyses, such as the assessment of molecular electrostatic potential, frontier molecular orbitals, and HOMO-LUMO energy gaps. For our molecular docking analysis, we used the Tdp1 catalytic domain in complex with an inhibitor (PDB ID: 6W7J) protein as the target. Both PP4CLB and PP24CLB used the same protein structure. The docking results indicated that PP24CLB demonstrated a marginally superior binding affinity (-8.03 kcal/mol) relative to PP4CLB (-7.89 kcal/mol). The interaction analysis showed that both ligands made several stabilising connections in the active site of 6W7J. PP24CLB had two hydrogen bonds and other non-covalent interactions. On the other hand, PP4CLB had other non-covalent interactions. The PASS prediction showed that our compound is very likely to have biological activity, with a Pa value of 0.849. This Pa score means that the compound is very likely to work as a Glycosylphosphatidylinositol phospholipase D (GPI-PLD) inhibitor.

The freshness of food is directly connected with safety, hygiene, and human health. Accurate quantification of biogenic amine level is crucial for assessing the food quality. Therefore, a dual-excitation ratiometric fluorescent probe MCCN based on hemicyanine dye for the examination of biogenic amines was constructed. After the addition of biogenic amines to the MCCN solution, an elimination reaction occurred after a nucleophilic addition reaction to form Schiff base MC-CA, resulting in colorimetric and ratiometric fluorescence responses. The probe MCCN solution was blue. After successively adding biogenic amines (cadaverine, n-butylamine and spermidine), the fluorescence emission intensity of probe MCCN at 709 nm reduced under excitation at 650 nm, meanwhile a new fluorescence emission peak emerged at 545 nm gradually increased under excitation at 450 nm, accompanying by a visible color variation from blue to yellow. The probe MCCN also displayed remarkable selectivity toward biogenic amines over other analytes. Based on the above excellent characteristics, the probe MCCN was successfully utilized to detect biogenic amines in the extract supernatant of shrimp and fish during the spoilage process. In addition, photographing the MCCN-loaded food extract supernatant enabled the correlation of color parameters with storage time, affording an accurate and simple method to reveal food spoilage process. The excellent sensing performance makes the MCCN probe a convenient and accurate screening platform for real-time assessing food freshness.

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.