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Dual-Site and Dual-Excitation Fluorescent Probe That Can Be Turned for Discriminative Detection of Cysteine, Homocystein, and Thiophenols
摘要： Thiols play a vital role in both the physiological process and organic synthesis field, including aliphatic thiols (e.g., Cys, Hcy, and GSH) and thiophenols. Due to the similarity of thiols in terms of molecular structure and chemical properties, it is difficult for conventional fluorescent probes to distinguish them, which hinders the progress of biological and pathological research. Keeping this in mind, a dual-site and dual-excite fluorescent probe (YY) was designed to distinguish Cys, Hcy, and thiophenols by three different reaction paths. When excited at 470 nm, YY only exhibits a fluorescence OFF-ON response towards thiophenols. However, when excited at 453 nm, YY not only displays a fluorescence OFF-ON response towards Hcy and thiophenols (λem = 499 and 561 nm) but also presents a two-stage fluorescence response towards Cys, which possesses a fluorescence OFF-ON response in the first stage (λem = 501 nm) and then a fluorescence ON-OFF response in the second stage (λem = 556 nm). This specific fluorescence response indicates that YY has ability to overcome the above-mentioned challenge to achieve discriminative detection of Cys, Hcy, and thiophenols qualitatively, which promotes the study of thiols in the field of physiology and pathology. Furthermore, cell-imaging studies show that YY can be applied to the imaging of exogenous Cys, Hcy, and thiophenols through two different emission channels.
关键词： thiophenols,discriminative detection,thiols,fluorescent probe,Cys,Hcy
更新于2025-09-23 15:21:01
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Development of a Selective Fluorescent Probe for Hypochlorous Acid Detection and Imaging
摘要： The reactive oxygen species (ROS), hypochlorous acid (HOCl), participates in many important biological events. For example, this ROS is the main active agent to kill invading microbes by immune system. HOCl is produced by H2O2 and Cl? in a myeloperoxidase (MPO) catalyzed process that occurs in response to inflammatory stimuli. Because HOCl reacts with important biological molecules and it causes cell damage, its uncontrolled production is involved in some human maladies such as arthritis. Detection and imaging HOCl in vivo are critical components of studies aimed at elucidating the biological functions of this ROS. Owing to several advantageous features including high selectivities and sensitivities, short response times and simple preparation methods, molecular fluorescent probes have become powerful tools for detecting biologically important substances and bio-imaging. It is essential to develop highly selective and sensitive fluorescent probes for HOCl for bio-applications. In the study described below, we demonstrated that spiro[isobenzofuran-30,60-dihydroxy-1(3H),90-[9H]thioxanthen]-3-one (TF) is an ideal fluorescent probe for HOCl because it undergoes a fluorescence enhancement upon being selectively chlorinated by this ROS.
关键词： Cell imaging,Fluorescent probe,Hypochlorous acid detection
更新于2025-09-23 15:21:01
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A coumarin-based dual optical probe for homocysteine with rapid response time, high sensitivity and selectivity
摘要： In this study, a new coumarin-based fluorescent and chromogenic dual channel probe (DC) was used for the selective detection of homocysteine (Hcy) over other amino acids, especially for cysteine (Cys) and glutathione (GSH). When Hcy is present in the solution, the remarkable fluorescence enhancement and obvious blue shift in UV–vis spectra can be observed. In addition, the color change from purple to yellow can be observed clearly by unaided eyes. This probe DC has fast response time, excellent sensitivity and selectivity to Hcy. A linear relationship exists between the ratio of emissions at 486 and 625 nm, and Hcy can be detected in a wide concentration range (0 to 200 μM). The signal-to-background ratio of fluorescence at 486 nm can reach 8.4, and the detection limit is calculated to be 3.5 μM. The response mechanism is proved to be the Michael addition reaction by Hcy. Preliminary results on cell imaging enable the practical application of Hcy tracing in living cells.
关键词： Sensor,Fluorescent probe,dual optical probe,Coumarin,Homocysteine,Cell imaging
更新于2025-09-23 15:19:57
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Nitrogen/sulfur-co-doped carbon quantum dots: a biocompatible material for the selective detection of picric acid in aqueous solution and living cells
摘要： Here, a fast and eco-friendly one-pot hydrothermal technique is utilized for the synthesis of nitrogen/sulfur-co-doped fluorescent carbon quantum dots (NS-CQDs) from a simple precursor of citric acid (CA) and thiosemicarbazide (TSC). The obtained NS-CQDs exhibited strong blue emission under UV light, with fluorescence quantum yield (QY) of ~37.8%. The Commission internationale de l’eclairage (CIE) coordinates originated at (0.15, 0.07), which confirmed the blue fluorescence of the synthesized NS-CQDs. Interestingly, the prepared NS-CQDs were successfully used as a selective nanoprobe for the monitoring of environmentally hazardous explosive picric acid (PA) in different nitro- and non-nitro-aromatic derivatives of PA. The mechanism of the NS-CQDs was also explored, and was posited to occur via the fluorescence resonance electron transfer (FRET) process and non-fluorescent complex formation. Importantly, this system possesses excellent biocompatibility and low cytotoxicity in HeLa cervical cancer cells; hence, it can potentially be used for PA detection in analytical, environmental, and pathological applications. Furthermore, the practical applicability of the proposed sensing system to pond water demonstrated the feasibility of our system along with good recovery.
关键词： Feasibility,PA,NS-CQDs,Cytotoxicity,Fluorescent probe,Synthesis
更新于2025-09-23 15:19:57
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MPA-CdTe quantum dots as a??on-off-ona?? sensitive fluorescence probe to detect ascorbic acid via redox reaction
摘要： Mercaptopropionic acid (MPA) capped CdTe quantum dots (MPA-CdTe QDs) were synthesized in aqueous medium by hydrothermal method, which modified by Fe3+ could be used as a fluorescent probe to detect ascorbic acid (AA). MPA-CdTe QDs fluorescence probe could be used as successive sensor for metal ions and AA with "on-off-on" process. The fluorescence of QDs was quenched after adding Fe3+ to MPA-CdTe QDs. Then, the fluorescence of the Fe3+@MPA-CdTe QDs can be sensitively turned on by AA to give an "on–off–on" fluorescence response according to the oxidation–reduction between Fe3+ and AA. There was a linear relationship between fluorescence intensity quenching value and the concentration of Fe3+ in the range of 2–10 μM since Fe3+ sensitively reacted with CdTe QDs. The linear detection range for AA was 0.1–1 μM with a limit of detection of 6.6 nM. The principle is proved by fluorescence emission spectroscopy, nuclear magnetic resonance spectroscopy. The proposed method is successfully used to detect the AA in human plasma sample.
关键词： CdTe quantum dots,Redox reaction,Fluorescent probe,Ascorbic acid
更新于2025-09-23 15:19:57
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Sulfur doped graphene quantum dots as a potential sensitive fluorescent probe for the detection of quercetin
摘要： In this work, a novel, selective and sensitive fluorescent probe (sulfur doped graphene quantum dots, SGQDs) was designed for real-time detection of quercetin in red wine samples. SGQDs were synthesized by pyrolyzing citric acid (CA) and 3-Mercaptopropionic acid (MPA) and characterized through advanced techniques. It was observed that fluorescence intensity of SGQDs could be substantially quenched by the addition of quercetin through inner filter effect (IFE) mechanism. Additionally, a visual color change (colorless to light yellow) was also noticed after addition of quercetin into a solution of SGQDs. The change in SGQDs fluorescence intensity with varying quercetin content revealed good linearity in the 0-50.0 μM range with regression coefficient of 0.9943 and a lowest detection limit of 0.006 μg/mL. To authenticate the real-time application of SGQDs as a potential fluorescent probe, red wine samples having different quercetin concentrations were used for quantitative analysis, after the optimization of several analytical parameters.
关键词： Sulfur doped graphene quantum dots,inner filter effect,pharmaceutical assay,fluorescent probe,quenching,quercetin
更新于2025-09-23 15:19:57
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Coumarin-Modified Graphene Quantum Dots as a Sensing Platform for Multicomponent Detection and Its Applications in Fruits and Living Cells
摘要： In this work, coumarin derivatives (C) are used to enhance the ?uorescence of graphene quantum dots (GQDs) by covalently linking the carboxyl groups on the edge of the GQD sheet. The as-synthesized coumarin-modi?ed graphene quantum dots (C-GQDs) have a uniform particle size with an average diameter of 3.6 nm. Simultaneously, the C-GQDs have strong ?uorescence emission, excellent photostability, and high ?uorescence quantum yield. C-GQDs and CN? can form a C-GQDs+CN? system due to deprotonation and/or intermolecular interactions. The introduced hydroquinone (HQ) is oxidized to benzoquinone (BQ), and the interaction between BQ and the C-GQDs+CN? system could lead to ?uorescence enhancement of C-GQDs. Meanwhile, the redox reaction between BQ and ascorbic acid (AA) can be used for quantitative detection of AA with CN? and HQ being used as substrates. Based on the above mechanism, C-GQDs are developed as a multicomponent detection and sensing platform, and the detection limits for CN?, HQ, and AA were 4.7, 2.2, and 2.2 nM, respectively. More importantly, satisfactory results were obtained when the platform was used to detect CN?, HQ, and AA in living cells and fresh fruits.
关键词： multicomponent detection,CN?,fluorescent probe,HQ,coumarin-modi?ed graphene quantum dots,AA
更新于2025-09-23 15:19:57
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A highly selective “turn-on” fluorescent probe for detecting Cu2+ in two different sensing mechanisms
摘要： A new coumarin-derived hydrazone (1) has been developed as a “turn-on” fluorescent probe for the detection of Cu2+ in two different sensing mechanisms. In anhydrous acetonitrile, the strong fluorescence response of 1 to Cu2+ was mainly attributed to the chelation-controlled C=N isomerisation. Besides, S-donor is indispensable in protecting from the Cu2+-induced fluorescence quenching. In aqueous acetonitrile, 1 as a chemodosimeter can highly selectively sense of Cu2+, which was ascribed to the Cu2+-promoted cyclization reaction affording the strong fluorescent cyclization product (2). The proposed cyclization reaction was confirmed by the single-crystal structure of 2. Furthermore, 1 was utilized for imaging intracellular Cu2+ with good performance.
关键词： Live cell imaging,Fluorescent probe,Copper ion,Coumarin,Cyclization
更新于2025-09-23 15:19:57
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Selective Visualization of Live-Cell Mitochondrial Thiophenols and Their Induced Oxidative Stress Process by a Rationally Designed Rhodol-Based Fluorescent Probe
摘要： Mitochondria as cellular powerhouses are the preferential targets affected by thiophenols, an important class of highly toxic environmental pollutants, and are linked to the production of pathogenic reactive oxygen species (ROS) induced by trace thiophenol residues. For real-time and accurate sensing, it is critically important to develop highly sensitive fluorescent probes for the specific detection of mitochondrial thiophenols. Herein, we report the first mitochondria-targeted fluorescent probe (ROAL) to image thiophenols in living cells. The development of ROAL was based on a novel red-emitting rhodol derivative (ROAP). ROAL proved to be highly selective to thiophenols among various analytes including aliphatic thiols, and renders an ultrasensitive off-on fluorescence response to thiophenols with a remarkable detection limit (8.1 nM). The probe efficiently stains mitochondria with a high Pearson’s co-localization coefficient (0.95) using Mito Tracker Green FM as reference, thereby ensuring the specific detection of mitochondrial thiophenols in living HepG2 and HeLa cells. In particular, using this probe we for the first time proved that endogenous reactive oxygen species have the capacity to eliminate thiophenols in living cells, suggesting that thiophenols might induce cellular oxidative stress.
关键词： oxidative stress damage,fluorescent probe,live-cell imaging,thiophenol,mitochondria-targeted
更新于2025-09-23 15:19:57
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A dual-channel probe with green and near-infrared fluorescence changes for in vitro and in vivo detection of peroxynitrite
摘要： In this study, a coumarin-semirhodamine hybrid based dual-channel fluorescent probe was developed for detection of peroxynitrite. This probe works well in nearly pure aqueous solution and displays a rapid, highly sensitive and selective response for peroxynitrite at two different emission wavelengths (700 and 515 nm, respectively), along with distinct color and green to near-infrared fluorescence changes. The fluorescent intensity ratio at 700 and 515 nm increases linearly with the concentration of peroxynitrite from 0 to 50 μM, and the detection limit is estimated to be 59 nM. Moreover, bioimaging of exogenous and endogenous peroxynitrite in living cells and in vivo detection of peroxynitrite with this probe at dual fluorescence channels were all successfully applied. The results suggest that this new probe can be used as a useful imaging tool for studying peroxynitrite in vitro and in vivo.
关键词： peroxynitrite,dual-channel,fluorescent probe,bioimaging,in vitro and in vivo
更新于2025-09-23 15:19:57