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A ratiometric fluorescence probe based on a novel recognition mechanism for monitoring endogenous hypochlorite in living cells
摘要： A ratiometric fluorescence probe (named ZOC) for the fast detection of HClO/ClO- was constructed by coumarin (donor) and pyridinium (acceptor) based on Forster resonance energy transfer (FRET) and intramolecular charge transfer (ICT) platform. ZOC possessed red emission signal (610 nm), large Stocks shift (190 nm), high energy transfer efficiency (95.3%), high selectivity and sensitivity, low detection limit (25 nM), wider detection range (from 25 nM to 30 μM), rapid response (within 13 S), and good biocompatibility. It was very interesting that the recognition mechanism involved a new organic reaction in which olefin double bond reacted first with HClO/ClO- regioselectively, followed by cyclization. ZOC was successfully used to the real time detection of endogenous HClO/ClO- in RAW 264.7 cells.
关键词： Hypochlorous acid/hypochlorite,Probe,Cell image,Ratiometric fluorescence,New mechanism
更新于2025-11-21 11:08:12
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Water-sensitive ratiometric fluorescent probes and application to test strip for rapid and reversible detection of water
摘要： Naphthalimide-decorated fluorinated acetamides 1 and 2 were developed as solvent-sensitive dual emissive fluorescence probes. Particularly, 1 exhibited dual emission with a large Stokes shift for water, DMF, and DMSO solvents over other various organic solvents. The dual emission might be due to the increase of intramolecular charge transfer (ICT) of the naphthalimide moiety through the association of the difluorinated acetamide group with the solvent molecules. The 1 can give rise to a ratiometric change in the dual emission and a visual fluorescent color change depending on the water contents in organic solvents, including ethanol, methanol, acetonitrile and DMF solvents. Moreover, the 1-impregnated paper strips showed a rapid and easy-to-visualize fluorescent color change enabling water detection in organic solvents. These simple-to-use paper strips were also found to be reusable over 20 times.
关键词： Naphthalimide,Ratiometric fluorescence probe,Reusable test strip,Intramolecular charge transfer (ICT),Water detection
更新于2025-11-19 16:46:39
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Bifunctional gold nanoclusters enable ratiometric fluorescence nanosensing of hydrogen peroxide and glucose
摘要： The accurate quantification of hydrogen peroxide (H2O2) and glucose is essential significance in clinical diagnosis. Herein a selective and sensitive ratiometric fluorescent nanosensor was developed for the determination of H2O2 and glucose by integrating peroxidase–like catalytic and fluorescent bifunctional properties of glutathione protected gold nanoclusters (GSH–AuNCs). The GSH–AuNCs exhibit inherent peroxidase–like activity and accelerate the decomposition of H2O2 into hydroxyl radicals. The produced hydroxyl radicals oxidize terephthalic acid (TA), a typical non–fluorescent substrate of peroxidase, to a highly fluorescent product hydroxyterephthalate (TAOH). Upon excitation with single–wavelength at 315 nm, dual–emission fluorescence peaks were recorded at 430 and 600 nm simultaneously. The fluorescence signal of TAOH at 430 nm continuously increased with increasing the concentration of H2O2 while the fluorescence signal of GSH–AuNCs at 600 nm remained unchangeable. Based upon on these facts, a ratiometric fluorescent nanosensor was fabricated for H2O2 assay with TAOH as response unit and GSH–AuNCs as reference, respectively. By converting glucose into H2O2 with catalytic oxidation of glucose oxidase (GOx), this nanosensor was further exploited for glucose assay. Under the optimum conditions, the detection limits of 10 nmol/L H2O2 and 20 nmol/L glucose were acquired. The relative standard deviations were less than 5% for both H2O2 and glucose (5.0 μmol/L solution, n = 11). The practicability of the nanosensor was verified by the determination of glucose in human serum samples. This nanosensor can be easily expanded as a general platform for the detection of other substances involving H2O2 produced or consumed.
关键词： Intrinsic peroxidase-like activity,Fluorescent gold nanoclusters,Hydrogen peroxide,Glucose,Ratiometric fluorescence,Nanosensor
更新于2025-11-14 17:03:37
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Dual-emission color-controllable nanoparticle based molecular imprinting ratiometric fluorescence sensor for the visual detection of Brilliant Blue
摘要： Single-component dual-emission nanoparticles were synthesized by chelating the organic ligand 8-hydroxyquinoline (HQ) to the surface of CdTe/ZnS quantum dots, namely CdTe/ZnQ2, and were used to construct a novel mesoporous structured molecular imprinting ratiometric fluorescence sensor by facile one-pot sol-gel polymerization for the visual detection of Brilliant Blue. The CdTe/ZnQ2 had bimodal fluorescence belonging to CdTe and ZnQ2 segments, respectively; significantly, the emission wavelength of CdTe was optimized to be 630 nm for the largest overlap with the absorption spectrum of Brilliant Blue. Consequently, fluorescence resonance energy transfer (FRET) efficiency was greatly enhanced, resulting in ideal determination. A favorable linearity toward Brilliant Blue was obtained within 0–1.0 μmol?L-1 along with profuse color evolution from orange to yellowish orange to yellowish green to green, and a high detectability of 8.8 nmol?L-1 was offered. Excellent recognition selectivity for Brilliant Blue over possibly coexistent food colorants was demonstrated, with a high imprinting factor of 7.1. Furthermore, endogenous Brilliant Blue was detected ranging from 0.21–41.03 mg/kg in six typical food samples with relative standard deviations lower than 3.5%, and the results agreed well with that afforded by conventional methods. Using Brilliant Blue as a model, this dual-emission color-controllable nanoparticle based imprinting ratiometric fluorescence sensor provided promising perspectives for the highly selective and sensitive, rapid, visual detection of colored substances in complicated matrices.
关键词： Molecular imprinting,Brilliant Blue,Dual-emission nanoparticles,Ratiometric fluorescence,Visual detection
更新于2025-09-23 15:23:52
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Ratiometric fluorescence imaging for sodium selenite in living cells
摘要： Sodium selenite as a common selenium-containing agent has been extensively studied for human health, especially cancer prevention and treatment. However, precisely evaluating the dynamic changes of sodium selenite at cellular and molecular level in these pharmacological and pathophysiological studies is still challenging. Developing the chemical tools that enable the quantification of sodium selenite in vivo with high spatial and temporal fidelity thus can provide an efficient solution to this challenge. Here, we report the design, synthesis and biological evaluation of ratiometric sodium selenite fluorescent probe (HBTN-Se) for quantitative ratiometric fluorescence imaging of sodium selenite concentration fluctuations in living cells. A strategy for sodium selenite quantification has been achieved effectively through using a highly selective, rapid and biocompatible hydroxyl-deprotecting reaction. The ratiometric fluorescence imaging with HBTN-Se is constructed to precisely monitor changes in sodium selenite levels in living cells. Moreover, HBTN-Se is capable of visualizing differences in sodium selenite levels between normal cells and cancer cells, establishing the utility of this ratiometric detection platform for assessing the correlation between physiological effects of sodium selenite and its levels in living cells.
关键词： Quantitative determination,Fluorescent probe,Sodium selenite,Ratiometric fluorescence imaging
更新于2025-09-23 15:22:29
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Rapid and On-site Detection of Uranyl Ions via Ratiometric Fluorescence Signals Based on a Smartphone Platform
摘要： Fluorescent quantum dots of carbon and semiconductor have superior optical properties and show great potential in sensing applications. This paper reports a novel method for rapid detection of uranyl ions via ratiometric fluorescence signals by employing the two types of quantum dots as the key materials. As the most soluble and stable toxic uranium species, uranyl has been recognized as an important index for nuclear industrial wastewater. However, its on-site, rapid and sensitive determination remains challenging. This work uses the ratiometric fluorescent signal of quantum dots and combines a smartphone-based handheld device for on-site and rapid detection of uranyl. The ratiometric fluorescent probe is achieved by integrating carbon dots (C-dots) and CdTe quantum dots (MPA@CdTe QDs) through chemical hybridization. The presence of uranyl ions greatly quenches the red ?uorescence of the CdTe QDs, whereas the green ?uorescence keeps constant, leading to obvious color change. An App and a 3D-printed accessory have been developed on a smartphone to analyze and calculate the content of uranyl on the basis of captured fluorescence signals from a test strip with immobilized probe. This new designed mobile detection system displays good analytical performance for urnayl ions in wide concentration range from 1 μM to 150 μM, which shows great potential application in controlling the nuclear industrial pollution.
关键词： 3D-printed,Smartphone,Ratiometric fluorescence sensor,Uranyl ions,APP
更新于2025-09-23 15:21:21
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Copper nanoclusters @ nitrogen-doped carbon quantum dots-based ratiometric fluorescence probe for lead (II) ions detection in porphyra
摘要： A novel ratiometric fluorescence probe was proposed for detecting lead (II) ions (Pb2+) in porphyra, the approach was based on copper nanoclusters and nitrogen-doped carbon quantum dots (CuNCs-CNQDs). In this probe, the CuNCs delivered the response signal, the fluorescence of which was enhanced by Pb2+ due to the aggregation-induced emission enhancement (AIEE) between Pb2+ and CuNCs. The CNQDs provided the self-calibration signal, whose fluorescence remained almost unchanged in coexistence with Pb2+. According to the change of fluorescence intensity ratio between the fluorophores, CuNCs–CNQDs nanohybrid was used as ratiometric probes for the sensitive detection of Pb2+ in the range of 0.010 to 2.5 mg L-1, with a detection limit of 0.0031 mg L-1. Finally, the probe was successfully applied to detect Pb2+ in porphyra with relative standard deviations (RSDs) lower than 5%. This study provides a straightforward, stable, and sensitive approach for detecting Pb2+ in porphyra.
关键词： Lead (II) ions,Ratiometric fluorescence probe,Aggregation-induced emission enhancement,Copper nanoclusters,Nitrogen-doped carbon quantum dots
更新于2025-09-23 15:21:01
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Determination of chondroitin sulfate in synovial fluid and drug by ratiometric fluorescence strategy based on carbon dots quenched FAM-labeled ssDNA
摘要： Chondroitin sulfate (CS) plays an increasingly important role in clinical settings and pharmacy quality control. However, sensitive and simple methods for CS detection remain limited. In this work, positively charged nitrogen doped carbon dots (P-NCDs) with internal luminescence and quenching property to FAM-labeled random-sequence ssDNA (F-ssDNA) were prepared by a simple heating method. P-NCDs attached and quenched F-ssDNA through electrostatic interaction to form the system of P-NCDs and F-ssDNA (P-NCDs/F-ssDNA) with retained fluorescence intensity of P-NCDs. The highly negatively charged CS reacted electrostatically with P-NCDs and then replaced F-ssDNA in P-NCDs/F-ssDNA to recover the fluorescence intensity of the original quenched F-ssDNA while retaining the internal fluorescence intensity of P-NCDs. Thus, by using restored F-ssDNA as the signal controlled by adding CS to P-NCDs/F-ssDNA, a ratiometric fluorescence strategy based on the retained fluorescence of P-NCDs as reference signal was fabricated through synchronous fluorescence spectrometry for the sensitive detection of CS. Under the optimal experimental conditions, a linear equation for CS was obtained for CS concentration within the range of 0.05–2.0 μg/mL. The method was also successfully applied for the accurate determination of CS in joint fluid samples of arthritic patients, chondroitin sulfate tablets, and chondroitin sulfate eye drops, suggesting its appreciable application potential in the clinic.
关键词： Positively charged nitrogen doped carbon dots (P-NCDs),Chondroitin sulfate,Synchronous fluorescence spectrometry,Ratiometric fluorescence strategy,Synovial fluid
更新于2025-09-23 15:19:57
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Recent advances in dual-emission ratiometric fluorescence probes for chemo/biosensing and bioimaging of biomarkers
摘要： A biomarker-based detection improves early diagnosis and subsequent treatment of diseases. Chemo/biosensing and bioimaging play a crucial role in biomarker detection. Ratiometric fluorescence (FL) probes provide built-in self-calibration for the correction of various target-independent factors and attract particular attention for analytical sensing and optical imaging. Based on the potential to provide a precise, quantitative, visual and real-time analysis, ratiometric FL probes are widely employed for chemo/biosensing and bioimaging detection of biomarkers. In this review, we systematically summarize the recent progress on dual-emission ratiometric FL probes. First, two general categories of ratiometric FL probes are introduced, involving ratiometric FL with one reference signal and two reversible signal changes. Then, fabrication methods of ratiometric FL probes are summarized in detail, including nanoparticle- or organic dye-embedded probes with dual-emission FL, fluorescent nanoparticles and organic dyes dual-embedded probes. Analytical applications of ratiometric FL probes are described overall, referring to different biomarker types and detection mechanisms, ratiometric FL chemo/biosensing in external samples and FL visual detection, ratiometric FL bioimaging in cells and tissues of small animals. Current states, probable challenges and future perspectives of ratiometric FL probes for biomarker detection are discussed rationally. This comprehensive review is attractive for numerous scientists from different areas, such as material science, chemistry, biomedicine, engineering, physics, etc. This review covers a wide range of scientific disciplines and benefits further development of functionalized optical materials, luminescent devices and bioimaging technique.
关键词： Biomarkers,Biosensors,Visual detection,Bioimaging,Ratiometric fluorescence
更新于2025-09-19 17:15:36
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A novel 1,8-naphthalimide as highly selective naked-eye and ratiometric fluorescent sensor for detection of Hg2+ ions
摘要： A novel colorimetric and ratiometric fluorescent chemosensor, 2-(2-mercaptophenyl)-1H-benzo[de]isoquinoline-1,3-(2H)-dione (L3) is reported for Hg2+ ions. The selective binding of Hg2+ to L3 afforded new absorbance and fluorescence peaks at 438 nm and 480 nm, in addition to the existing bands of L3 at 332 nm and 376 nm. It also showed apparent colour change from colourless to yellowish green and weak fluorescent to bright yellowish green strong fluorescent due to selective binding of Hg2+ ion. The sensor forms a 1:1 stoichiometry with high binding constants (3.89 × 10^4 mol^-1 L) and limit of detection 1.74 × 10^-8 M with high selectivity and sensitivity towards Hg2+ in the presence of other interfering metal ions. More importantly, it has good practicability in environmental water sample. The outcome of photo-physical experiment has also been in good accordance with the time-resolved fluorescence life decays and the density functional theory (DFT) estimations. Moreover, the L3-Hg2+ solution displayed high colorimetric and fluorimetric reversibility via the addition of KI. This reversibility in fluorescence showed potential applicability of chemosensor L3 as 'on–off–on' naked eye sensor.
关键词： Molecular logic gate,Red-shift,DFT,Off–on–off Hg2+ chemosensor,Naked eye detection,Ratiometric fluorescence
更新于2025-09-19 17:15:36