- 标题
- 摘要
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- 实验方案
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MnO2 Nanosheet-mediated Ratiometric Fluorescence Biosensor for MicroRNA Detection and Imaging in Living Cells
摘要： MicroRNA (miRNA) plays significant roles in cell proliferation, differentiation and apoptosis, and has been considered to be valuable biomarker for cancer. Accurate and sensitive detection of miRNA is crucially significant for cancer diagnosis and treatment. Here, a MnO2 nanosheet-mediated ratiometric fluorescence biosensor was designed for miRNA detection and imaging in living cells. It contained MnO2 nanosheets acting as DNA carrier, and fluorescent donor (FAM)-labeled hairpin H1 (recognition probe) and fluorescent acceptor (TAMRA)-labeled hairpin H2 (amplification probe). When the biosensor entered cell by endocytosis, MnO2 nanosheets were degraded to Mn2+ via intracellular glutathione (GSH) and the adsorbed hairpins H1 and H2 were released. The intracellular target miRNA-21 hybridized with the recognition unit of H1 to initiate catalyzed hairpin assembly (CHA) and a large amount of H1-H2 duplexes were produced. This brought fluorescent donor FAM and fluorescent acceptor TAMRA into close proximity to produce fluorescence resonance energy transfer (FRET), inducing a ratiometric fluorescent response (donor signal decreased and acceptor signal enhanced) for miRNA-21 detection. Furthermore, this method could be applied to differentiate the expression levels of miRNA-21 in HeLa, HepG-2 and L02 cells. These results indicated that the proposed method possessed great potential in the early diagnosis of miRNA-related diseases.
关键词： MicroRNA detection,MnO2 nanosheets,Ratiometric,Cell imaging
更新于2025-11-21 11:24:58
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A through-bond energy transfer-based ratiometric fluorescent pH probe: For extreme acidity and extreme alkaline detection with large emission shifts
摘要： A ratiometric fluorescence pH probe 1 based on through-bond energy transfer (TBET) with a 2-(2-hydroxyphenyl)benzoxazole (HBO) as donor and a Rhodamine derivative as acceptor is developed through simple condensation reaction. The probe exhibits a ratiometric fluorescence emission (I593/I422) characteristics and linear response to extreme acidity range of 5.00-2.88, and a ratiometric fluorescence emission (I555/I422) characteristics and linear response to extreme alkaline range of 10.00-13.78, respectively. Moreover, 1 possesses highly selective response to pH over metal ions, good reversibility and excellent photostability. Probe 1 is cellpermeable and can distinguish near pH 5.55 fluctuations in Hela cells. Furthermore, 1 can be immobilized on a test paper, which shows a rapid and reversible colorimetric response to HCl/NH3 vapor by the naked-eye.
关键词： ratiometric fluorescent response,pH sensing,large emission shifts,through-bond energy transfer,fluorescent probe
更新于2025-11-21 11:24:58
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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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A near-infrared BODIPY-based fluorescent probe for ratiometric and discriminative detection of Hg2+ and Cu2+ ions in living cells
摘要： A near-infrared distyryl boron dipyrromethene-based sensor bearing one bis(1,2,3-triazole)amino receptor has been synthesized. This probe selectively and quickly binds to Hg2+ and Cu2+ ions in CH3CN/H2O (5:1 v/v) and exhibits remarkably blue-shifted absorption and fluorescence bands due to the inhibition of the intramolecular charge transfer process. The fluorescence changes of this probe upon binding to Hg2+ or Cu2+ ion are totally different, undergoing a ratiometric fluorescence enhancement (for Hg2+) or a fluorescence quenching (for Cu2+) mechanism. The corresponding vivid color changes can be easily seen by the naked eye. This probe was further introduced into Hela cells for living cell imaging and found to discriminate Hg2+ and Cu2+ ions through two near-infrared fluorescence emission channels. These overall results indicate that this Click-derived near-infrared BODIPY-based probe is potentially useful for ratiometric and discriminative detection of Hg2+ and Cu2+ ions in solutions and living cells.
关键词： Discriminative detection,Ratiometric,Hg2+ and Cu2+ sensor,Near-infrared,BODIPY
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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Magnesium tetrapyrazinoporphyrazines: tuning of the pKa of red-fluorescent pH indicators
摘要： Magnesium (II) tetrapyrazinoporphyrazines (TPyzPzs) are excellent red fluorophores (λF ~ 663 nm, ΦF ~ 0.53 in THF). In this work, a series of magnesium (II) complexes of unsymmetrical TPyzPzs bearing one or two phenol substituents was prepared. Suitable substitutions on the phenolic moiety tuned its pKa in the range of 5.5 to 13. Deprotonation of the phenolic group at higher pH induced a strong donor (phenolate) in the macrocycle that led to pH-dependent quenching of the red fluorescence of these indicators. pH sensing was proven in water solutions after incorporation of TPyzPs into two delivery systems – microemulsions and liposomes. The latter also serves as a simple model of biomembranes. Finally, a wavelength-ratiometric probe was constructed by incorporation of a TPyzPz indicator and lipophilic pH-nonsensitive BODIPY dye into liposomes. Synthetic precursors for TPyzPzs, substituted pyrazine-2,3-dicarbonitriles, also represent donor-acceptor system and the pH-dependent changes in absorption spectra may be easily visible to the naked eye.
关键词： pH indicators,microemulsions,fluorescence,BODIPY,wavelength-ratiometric probe,liposomes,tetrapyrazinoporphyrazines,magnesium complexes
更新于2025-11-20 15:33:11
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A mitochondria-targeted ratiometric fluorescent probe for detection of SO2 derivatives in living cells and in vivo
摘要： A new near-infrared (NIR) ?uorescent probe for colorimetric and ratiometric detection of SO2 derivatives was developed based on conjugated hybrid coumarin-hemicyanine. The probe can detect HSO3?/SO32? in HEPES bu?er (10 mM, pH 7.4, with 10% DMF, v/v) with a large emission shift (259 nm). Importantly, it was successfully used for ?uorescence imaging of endogenous bisul?te in BT-474 cells and zebra?sh.
关键词： Near-infrared ?uorescent probe,SO2 derivatives,Mitochondria-targeted,Ratiometric,Colorimetric
更新于2025-11-19 16:56:35
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Cationic porphyrins with large side arm substituents as resonance light scattering ratiometric probes for specific recognition of nucleic acid G-quadruplexes
摘要： Specific G-quadruplex-probing is crucial for both biological sciences and biosensing applications. Most reported probes are focused on fluorescent or colorimetric recognition of G-quadruplexes. Herein, for the first time, we reported a new specific G-quadruplex-probing technique—resonance light scattering (RLS)-based ratiometric recognition. To achieve the RLS probing of G-quadruplexes in the important physiological pH range of 7.4-6.0, four water soluble cationic porphyrin derivatives, including an unreported octa-cationic porphyrin, with large side arm substituents were synthesized and developed as RLS probes. These RLS probes were demonstrated to work well for ratiometric recognition of G-quadruplexes with high specificity against single- and double-stranded DNAs, including long double-stranded ones. The working mechanism was speculated to be based on the RLS signal changes caused by porphyrin protonation that was promoted by the end-stacking of porphyrins on G-quadruplexes. This work adds an important member in G-quadruplex probe family, thus providing a useful tool for studies on G-quadruplex-related events concerning G-quadruplex formation, destruction and changes in size, shape and aggregation. As a proof-of-concept example of applications, the RLS probes were demonstrated to work well for label-free and sequence-specific sensing of microRNA. This work also provides a simple and useful way for the preparation of cationic porphyrins with high charges.
关键词： G-quadruplex,ratiometric recognition,microRNA sensing,resonance light scattering,cationic porphyrin
更新于2025-11-19 16:56:35
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Opposite changing dual-emission luminescence of gold nanoparticles by sulfhydryl to develop a pesticide biosensing strategy
摘要： As the merit of ratiometric assay is impregnable due to potentially interfering processes, a ratiometric method for pesticide detection was developed. By adjusting glutathione : HAuCl4 to an appropriate ratio, dual-emission luminescent ultra-small gold nanoparticles (AuNPs) with a high emission at 800 nm and a low emission at 600 nm were synthesized. Interestingly, the sulfhydryl-containing compounds were found to result in completely opposite changes to strengthen the 600 nm emission and weaken the 800 nm emission. Therefore, dual-emitted AuNPs were engaged to develop a ratiometric pesticide biosensing strategy. In the presence of acetylcholinesterase (AChE), acetylthiocholine can be hydrolyzed into thiocholine, whose newly generated sulfhydryl can interact with AuNPs, resulting in the opposite change of the dual emissions. While adding pesticide as an AChE inhibitor, the catalytic activity of AChE is inhibited and less thiocholine was produced. The biosensing system shows an obvious sensitivity to the pesticide with a limit of detection (LOD) of 0.2 nM for aldicarb and 0.07 nM for chlorpyrifos. Therefore, this simple assay is suitable for AChE activity and pesticide detection, even in vegetable samples.
关键词： sulfhydryl,ratiometric assay,gold nanoparticles,AChE activity,biosensing,pesticide detection
更新于2025-11-19 16:56:35
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An AND logic gate-based fluorescence probe for the detection of homovanillic acid, an indicator of the tumor
摘要： Homovanillic acid (HVA) is one of the major metabolites of catecholamine in human. An elevated level of HVA in urine and blood has been associated with many diseases, including catecholamine-secreting tumors. Consequently, detection of the biomarker HVA in urine is an effective strategy to detect cancer precursors and early stage cancers. In this study, a fluorescence probe is designed and fabricated by integrating lanthanide ions with metal-organic frameworks (MOFs). The fluorescence probe shows distinguished response toward HVA and exhibits ratiometric detection of HVA, rendering it an excellent candidate for sensing devices. Thus, we have designed logic gate operation integrating the probe with logical operations for the intelligent sensing of HVA. Furthermore, this type of luminesce based sensors integrated with logic gate augur for the further application in real-time early diagnosis of tumors in the future.
关键词： Rare earth,Homovanillic acid,Fluorescent probe,Logic gate,Ratiometric sensing,Metal-organic frameworks
更新于2025-11-19 16:56:35