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On-off-on relay fluorescence recognition of ferric and fluoride ions based on indicator displacement in living cells
摘要： A new boronic acid derivative functionalized with a 4-(3-(4-(4,5-diphenyl-1H-imidazol-2-yl)phenyl)-1,2,4-oxadiazol-5-yl)phenyl (IOP) moiety was synthesized for use as a sequential “on-off-on”-type relay fluorescence probe for Fe3+ ions and F? ions with high selectivity and sensitivity under physiological conditions. The introduction of Fe3+ to IOP boronic acid (IOPBA) formed an Fe3+-IOPBA complex, which led to quenching of the blue fluorescence intensity at 458 nm. The lowest-energy conformation of IOPBA was theoretically predicted to adopt an extended structure, and the Fe3+ ion in the Fe3+-IOPBA complex was coordinated to two phenyl groups to form a p-complex. Upon addition of F? to the Fe3+-IOPBA complex, the original fluorescence was recovered due to formation of [FeF6]3?, resulting in “on-off-on”-type sensor behavior. IOPBA showed high selectivity towards Fe3+ among other cations. Moreover, the Fe3+-IOPBA complex showed specific selectivity towards F?, with other cations and anions not interfering with detection. Both sensing processes showed 1:1 stoichiometry with binding constants of 6.87 × 106 and 4.49 × 106 mol–1 L for Fe3+ with IOPBA and F? with Fe3+-IOPBA, respectively. The limits of detection for Fe3+ and F? were 10 and 1 nM, respectively. The proposed method was successfully applied in real water samples. Furthermore, the probe had low cytotoxicity and was successfully used as a bioimaging reagent to detect intracellular Fe3+ and F? in living HeLa cells.
关键词： Fluorescence imaging,On-off-on sensor,Probe for Fe3+ ions and F? ions,Living HeLa cells,Boronic acid derivative
更新于2025-11-21 11:08:12
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A red fluorescent BODIPY probe for iridium (III) ion and its application in living cells
摘要： A new red fluorescent probe 1 based on BODIPY skeleton has been successfully synthesized through introduction of 2-(thiophen-2-yl) quinoline moiety at meso- and 3-position, which exhibits excellent optical performance, including high fluorescence quantum yield, large pseudo Stokes’ shift as well as high selectivity and sensitivity towards iridium (III) ion in aqueous solution and in living cells.
关键词： iridium (III) ion probe,fluorescence imaging,BODIPY probe
更新于2025-11-21 11:08:12
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Evaluation of various tissue-clearing techniques for the three-dimensional visualization of liposome distribution in mouse lungs at the alveolar scale
摘要： Purpose: To develop a three-dimensional visualization method for evaluating the distribution of pulmonary drug delivery systems and compare four tissue-clearing techniques (ClearT2, CUBIC, ScaleS, and SeeDB2) using intrapulmonary liposomes as drug carriers. Methods: Rhodamine B-labeled liposomes were administered intrapulmonarily to mice using a MicroSprayer, and then fluorescent-labeled tomato lectin was administered intravenously to visualize the general lung structure. Tissue-clearing treatment of the mouse lungs was performed using the standard protocols of the ClearT2, CUBIC, ScaleS, and SeeDB2 techniques. Lung clearing was clarified using laser-scanning confocal microscopy, and three-dimensional images were reconstructed. Results: Fluorescent-labeled tomato lectin was preserved using ClearT2 and SeeDB2 but not using CUBIC and ScaleS. In addition, the liposomes were stable in ClearT2 reagent, but they were mostly degraded in other reagents by surface-active agents. ClearT2 treatment enabled the three-dimensional visualization of intrapulmonary rhodamine B-labeled liposomes at the alveolar scale. Conclusions: These results suggest that the ClearT2 tissue-clearing technique was appropriate for the three-dimensional visualization of intrapulmonary liposomes at the alveolar scale. This study provides important information for selecting and optimizing suitable optical tissue-clearing techniques in lungs for evaluating the distribution of pulmonary drug delivery systems.
关键词： fluorescence preservation,Intrapulmonary distribution,inhalation,liposomes,drug delivery systems,laser-scanning confocal microscopy
更新于2025-11-21 11:08:12
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Perylenequinone-based “turn on” fluorescent probe for hydrogen sulfide with a high sensitivity in living cells
摘要： Hydrogen sulfide (H2S) is a kind of gaseous signal molecule in many physiological processes. In order to detect H2S, a novel “turn on” fluorescent probe 6,12-dihydroxyperylene-1,7-dione (DPD) was designed and synthesized. The probe DPD is fluorescence silence, while the addition of H2S induces an obvious green fluorescence with an obvious color change from dark blue to yellow-green. The probe shows excellent selectivity, fast response (2.5 minutes) and linear curve (0-90 μM) in wide effective pH range (4-10). Competition experiments are also revealed in corresponding studies and the detection limit is 3.6 μM. The response mechanism is proved to be the reduction of the probe by H2S, which is confirmed by 1H NMR. Furthermore, through the fluorescence turn-on signal toward H2S in Hela cells, probe DPD was successfully applied to monitor H2S in living Hela cells.
关键词： hydrogen sulfide,probe,fluorescence imaging,cell imaging,perylenequinone
更新于2025-11-21 11:08:12
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Selective Detection of Trinitrophenol by Amphiphilic Dimethylaminopyridine-Appended Zn(II)phthalocyanines at the Near-Infrared Region
摘要： Novel amphiphilic Zn(II)phthalocyanines (ZnPcs) peripherally substituted with four and eight dimethylaminopyridinium units (ZnPc1 and ZnPc2) were synthesized by cyclotetramerization of the corresponding phthalonitriles. The effect of aggregation and photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation under light irradiation) properties was investigated. The chemosensing ability of ZnPcs toward explosive nitroaromatic compounds was explored in aqueous medium. This study demonstrates that ZnPc1 and ZnPc2 show fluorescence quenching behavior upon interaction with different nitro analytes and show unprecedented selectivity toward 2,4,6-trinitrophenol with a limit of detection (LOD) of 0.7?1.1 ppm with a high quenching rate constant (Ksv) of 1.6?2.02 × 105. The near-infrared (NIR) fluorescence in thin films was quenched efficiently because of the photoinduced electron-transfer process through strong intermolecular π?π and electrostatic interactions. The sensing process is highly reversible and free from the interference of other commonly encountered nitro analytes. Further, experiments were performed to demonstrate the use of ZnPcs as efficient heterogeneous photocatalysts in the reduction of nitro explosives. The smart dual performance of multicharged ZnPcs in aqueous media quantifies them as attractive candidates in developing sensor materials at the NIR region and to possibly convert the toxic explosives into useful scaffolds. These results provide an interesting perspective toward elaboration of stable fluorescent systems for the selective sensing behavior of nitro explosives and their facile heterogeneous catalytic behavior in the reduction reactions.
关键词： trinitrophenol,photocatalysis,explosive detection,near-infrared,fluorescence quenching,dimethylaminopyridinium,Zn(II)phthalocyanines
更新于2025-11-21 11:08:12
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A new FRET-based ratiometric fluorescence probe for hypochlorous acid and its imaging in living cells
摘要： A novel ratiometric fluorescence probe for hypochlorous acid was constructed by coumarin and pyridinium fluorophore based on the Forster resonance energy transfer (FRET) and intramolecular charge transfer (ICT) platform. In this ICT/FRET system, the energy transfer efficiency is high to 94.3%. Moreover, the probe could respond to hypochlorous acid with high selectivity and sensitivity, and exhibited a large Stokes shift. It was interesting to find that the probe could recognize hypochlorous acid via a new mechanism, in which the a -position of carbonyl group was oxidized to form a diketone derivative. More importantly, the probe was successfully applied to the ratiometric imaging of both exogenous and endogenous hypochlorous acid in living RAW 264.7 cells, with low toxicity and high photo-stability.
关键词： New reaction mechanism,FRET,Hypochlorous acid,Fluorescence probe,Cell image,Ratiometric
更新于2025-11-21 11:08:12
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Core-shell metal-organic frameworks with fluorescence switch to trigger an enhanced photodynamic therapy
摘要： The design of hybrid metal-organic framework (MOF) nanomaterials by integrating inorganic nanoparticle into MOF (NP@MOF) has demonstrated outstanding potential for obtaining enhanced, collective, and extended novel physiochemical properties. However, the reverse structure of MOF-integrated inorganic nanoparticle (MOF@NP) with multifunction has rarely been reported. Methods: We developed a facile in-situ growth method to integrate MOF nanoparticle into inorganic nanomaterial and designed a fluorescence switch to trigger enhanced photodynamic therapy. The influence of “switch” on the photodynamic activity was studied in vitro. The in vivo mice with tumor model was applied to evaluate the “switch”-triggered enhanced photodynamic therapy efficacy. Results: A core-satellites structure with fluorescence off and on function was obtained when growing MnO2 on the surface of fluorescent zeolitic imidazolate framework (ZIF-8) nanoparticles. Furthermore, A core-shell structure with photodynamic activity off and on function was achieved by growing MnO2 on the surface of porphyrinic ZrMOF nanoparticles (ZrMOF@MnO2). Both the fluorescence and photodynamic activities can be turned off by MnO2 and turned on by GSH. The GSH-responsive activation of photodynamic activity of ZrMOF@MnO2 significantly depleted the intracellular GSH via a MnO2 reduction reaction, thus triggering an enhanced photodynamic therapy efficacy. Finally, the GSH-reduced Mn2+ provided a platform for magnetic resonance imaging-guided tumor therapy. Conclusion: This work highlights the impact of inorganic nanomaterial on the MOF properties and provides insight to the rational design of multifunctional MOF-inorganic nanomaterial complexes.
关键词： Core-shell structure,Metal-organic frameworks,Fluorescence switch,Photodynamic therapy
更新于2025-11-21 11:08:12
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Facile Synthesis of Luffa Sponge Activated Carbon Fiber Based Carbon Quantum Dots with Green Fluorescence and Their Application in Cr(VI) Determination
摘要： Carbon quantum dots (CQDs) were prepared by a chemical oxidation method using lu?a sponge based activated carbon ?ber as the raw material. The obtained CQDs were well characterized. The ?uorescence quenching e?ect of Cr(VI) ion on CQDs was investigated. The results show that the addition of Cr(VI) changes the intensity of the ultraviolet characteristic absorption peak of CQDs, and causes static quenching of the ?uorescence of CQDs. With the increase in the Cr(VI) concentration, the ?uorescence of CQDs was gradually extinguished linearly.
关键词： Activated carbon ?ber,Lu?a sponge,Cr(VI) determination,Fluorescence quenching,Carbon quantum dots
更新于2025-11-21 11:01:37
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Highly sensitive and selective label-free detection of dopamine in human serum based on nitrogen-doped graphene quantum dots decorated on Au nanoparticles: Mechanistic insights through microscopic and spectroscopic studies
摘要： A rapid, facile and label-free sensing strategy is developed for the detection of dopamine (DA) in the real samples by exploiting nitrogen-doped graphene quantum dots (N-GQDs) decorated on Au nanoparticles (Au@N-GQD). The as-grown Au@N-GQD exhibits strong blue fluorescence at room temperature and the fluorescence intensity is drastically quenched in presence of DA in neutral medium. The mechanistic insight into the DA sensing by Au@N-GQDs is explored here by careful monitoring of the evolution of the interaction of Au NPs and N-GQDs with DA under different conditions through electron microscopic and spectroscopic studies. The highly sensitive and selective detection of DA over a wide range is attributed to the unique core-shell structure formation with Au@N-GQD hybrids. The quenching mechanism involves the ground state complex formation as well as electron transfer from N-GQDs. The presence of Au NPs in Au@N-GQD hybrids accelerates the quenching process (~14 fold higher than bare N-GQDs) by the formation of stable dopamine-o-quinone (DQ) in this present detection scheme. The fluorescence quenching follows the linear Stern-Volmer plot in the range 0-100 μM, establishing its efficacy as a fluorescence-based DA sensor with a limit of detection (LOD) 590 nM, which is ~27 fold lower than the lowest abnormal concentration of DA in serum (16 μM). This sensing scheme is also successively applied to trace DA in Brahmaputra river water sample with LOD 480 nM including its satisfactory recovery (95-112%). Our studies reveal a novel sensing pathway for DA through the core-shell structure formation and it is highly promising for the design of efficient biological and environmental sensor.
关键词： Dopamine,Fluorescence quenching,Nitrogen-doped graphene quantum dots,Colorimetric sensing,Core-shell structure,Gold nanoparticles
更新于2025-11-21 11:01:37
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Aminoboronic acid-functionalized graphitic carbon nitride quantum dots for the photoluminescence multi-chemical sensing probe
摘要： This paper reports a highly sensitive photoluminescence glucose sensor based on aminoboronic acid-functionalized carbon nitride quantum dots (g-CNQDs/3APBA) fabricated using melamine and 3-aminophenylboronic acid via a facile two-step synthesis process. By introducing the covalent bonds between g-CNQDs and boronic acid groups, it can be effectively used as “on-off-on” based multi-chemical sensor. The g-CNQDs/3APBA exhibited quantum yields (QYs) as high as 78.5%, which is the highest QYs among fluorescence sensors based on g-CNQDs reported thus far. The material showed a wide linear range of 0 – 10 mM and a detection limit as low as 42 nM with excellent selectivity. In addition, it exhibited comparable performance compared to those of a commercial glucometer in a real blood test. Owing to the excellent bio-imaging properties and low cytotoxicity, g-CNQDs/3APBA is a promising candidate as a sensing material for biomedical and clinical applications.
关键词： quantum dots,glucose sensor,multi-chemical sensor,fluorescence,Graphitic carbon nitride,3-aminophenylboronic acid
更新于2025-11-20 15:33:11