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Paper sensor of curcumin by fluorescence resonance energy transfer on nitrogen-doped carbon quantum dot
摘要： Paper Sensor detection methods are attractive in wide analytical applications. Presented herein is a paper sensor and ?uorescence methods that was ?rstly developed to detect curcumin (Cur) based on ?uorescence resonance energy transfer (FRET) between nitrogen-doped carbon quantum dots (NCQDs) and Cur. The facile ?uorescent method was demonstrated to detect Cur in the range of 0e2600 mM with a detection limit of 0.13 mM. And facile paper sensor of Cur was fabricated and displayed at concentration of 0 mM, 100 mM, 200 mM, 300 mM, 400 mM, 500 mM and 600 mM, respectively. In additions, it was realized for determination of Cur in real samples including orange juice and curry solution. Compared with the reported methods, the present method is simple, rapid and sensitive for detecting Cur.
关键词： Nitrogen-doped carbon quantum dots (NCQDs),Curcumin (Cur),Fluorescence resonance energy transfer (FRET),Paper-based sensor
更新于2025-09-11 14:15:04
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Precisely Encoded Barcodes Using Tetrapod CdSe/CdS Quantum Dots with a Large Stokes Shift for Multiplexed Detection
摘要： A serious obstacle to the construction of high-capacity optical barcodes in suspension array technology is energy transfer, which can prompt unpredictable barcode signals, limited barcode numbers, and the need for an unfeasible number of experimental iterations. This work reports an effective and simple way to eliminate energy transfer in multicolor quantum dots (QDs)-encoded microbeads by incorporating tetrapod CdSe/CdS QDs with a large Stokes shift (about 180 nm). Exploiting this unique feature enables the facile realization of a theoretical 7 × 7-1 barcoding matrix combining two colors and seven intensity levels. As such, microbeads containing tetrapod CdSe/CdS QDs are demonstrated to possess a powerful encoding capacity which allows for precise barcode design. The ability of the Shirasu porous glass membrane emulsification method to easily control microbead size facilitates the establishment of a 3D barcode library of 144 distinguishable barcodes, indicating the enormous potential to enable large-scale multiplexed detection. Moreover, when applied for the multiplexed detection of five common allergens, these barcodes exhibit superior detection performance (limit of detection: 0.01–0.02 IU mL?1) for both spiked and patient serum samples. Therefore, this new coding strategy helps to expand barcoding capacity while simultaneously reducing the technical and economic barriers to the optical encoding of microbeads for high-throughput multiplexed detection.
关键词： large Stokes shift,F?rster resonance energy transfer (FRET),photon re-absorption,quantum dots-encoded microbeads,multiplexed detection
更新于2025-09-11 14:15:04
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Quantum Dots for Monitoring Choline Consumption Process of Living Cells via an Electrostatic Force-Mediated Energy Transfer
摘要： In this work, a ratiometric nanoprobe CdS/ZnS-FB was designed for H2O2 detection based on FRET assay. Furthermore, CdS/ZnS-FB could work for detecting choline (Ch) and acetylcholine (ACh) since H2O2 is the enzyme cascade reaction product. Significantly, choline consumption could also be quantitatively measured by monitoring FRET ratio (I522 /I426). Thus, the biosensor could be applied as a universal tool for the detection of choline consumption of living cells, which provides a good potential for the applications in detecting chemical transmitter and cancer diagnosis.
关键词： H2O2,living cells,enzyme cascade reaction,FRET,quantum dots
更新于2025-09-11 14:15:04
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A Novel Rare Earth Ion Fluorescent Probe towards the Trace Detection of 2,4,6-Trinitrotoluene Based on Fluorescence Resonance Energy Transfer
摘要： This paper reports a resonance energy transfer-fluorescence quenching of the core-shell structure of CaMoO4:Tb3+@SiO2 modified by amino group on the surface for the ultrasensitive and ultratrace detection of 2,4,6-trinitrotoluene (TNT) in solution environments. Organic amine was covalently modified onto the surface of silica shell to form a hybrid monolayer of amino group. The particle can specifically bind TNT species by the charge-transfer complexing or acid-base pairing interactions between electron-rich amine ligands and electron-deficient aromatic rings. The resultant TNT-amine complexes bound at the silica surface can strongly suppress the fluorescence emission of the chosen dye by the fluorescence resonance energy transfer (FRET) from CaMoO4:Tb3+ fluorescence donor to the irradiative TNT-amine acceptor through intermolecular polar-polar interactions at spatial proximity. The nanoparticle can sensitively detect down to 1 nM TNT with the use of only 10 μL of solution (2 pg TNT). The simple FRET-based nanoparticle sensors reported here exhibit a high and stable fluorescence brightness, strong analyte affinity and good assembly flexibility and can thus find many applications in the detection of ultratrace analytes.
关键词： Fluorescence quenching,FRET,Ultratrace detection,2,4,6-Trinitrotoluene,Rare earth ion
更新于2025-09-11 14:15:04
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Design of Novel Pyrene-Bodipy Dyads: Synthesis, Characterization, Optical Properties, and FRET Studies
摘要： A new series of dendronized bodipys containing pyrene units was synthesized and characterized. Their optical and photophysical properties were determined by absorption and ?uorescence spectroscopy. This series includes three different compounds. The ?rst one has an anisole group linked to the bodipy unit, which was used as the reference compound. In the second, the bodipy core is linked to a zero generation dendron with one pyrene unit. The third In this compound contains a ?rst generation Fréchet-type dendron bearing two pyrene units. work, the combination pyrene-bodipy was selected as the donor-acceptor pair for this ?uorescence resonance energy transfer (FRET) study. Doubtless, these two chromophores exhibit high quantum yields, high extinction coef?cients, and both their excitation and emission wavelengths are located in the visible region. This report presents a FRET study of a novel series of pyrene-bodipy dendritic molecules bearing ?exible spacers. We demonstrated via spectroscopic studies that FRET phenomena occur in these dyads.
关键词： ?uorescence resonance energy transfer (FRET),pyrene,bodipy
更新于2025-09-10 09:29:36
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Bright near-infrared fluorescence bio-labeling with a biliprotein triad
摘要： Biliproteins have extended the spectral range of fluorescent proteins into the near-infrared region (NIR, 700–770 nm) of maximal transmission of most tissues and are also favorable for multiplex labeling. Their application, however, presents considerable challenges to increase their stability under physiological conditions and, in particular, to increase their brightness while maintaining the emission in near-infrared regions: their fluorescence yield generally decreases with increasing wavelengths, and their effective brightness depends strongly on the environmental conditions. We report a fluorescent biliprotein triad, termed BDFP1.1:3.1:1.1, that combines a large red-shift (722 nm) with high brightness in mammalian cells and high stability under changing environmental conditions. It is fused from derivatives of the phycobilisome core subunits, ApcE2 and ApcF2. These two subunits are induced by far-red light (FR, 650–700 nm) in FR acclimated cyanobacteria. Two BDFP1.1 domains engineered from ApcF2 covalently bind biliverdin that is accessible in most cells. The soluble BDFP3 domain, engineered from ApcE2, binds phytochromobilin non-covalently, generating BDFP3.1. This phytochromobilin chromophore was added externally; it is readily generated by an improved synthesis in E. coli and subsequent extraction. Excitation energy absorbed in the FR by covalently bound biliverdins in the two BDFP1.1 domains is transferred via fluorescence resonance energy transfer (FRET) to the non-covalently bound phytochromobilin in the BDFP3.1 domain fluorescing in the NIR around 720 nm. Labeling of a variety of proteins by fusion to the biliprotein triad is demonstrated in prokaryotic and mammalian cells, including human cell lines.
关键词： Bioimaging,Biliprotein,FRET,Allophycocyanin,Biomarker,Biliverdin
更新于2025-09-10 09:29:36
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MicroRNA Quantitation During Dendritic Cell Endocytosis Using Imaging Flow Cytometry: Key Factors and Requirements
摘要： Background/Aims: MicroRNA (miRNA)-induced suppression of dendritic cells (DCs) has been implicated in many diseases. Therefore, accurate monitoring of miRNA endocytosis by DCs is important for understanding the role of miRNAs in many diseases. Recently, a method for measuring the co-localization of Argonaute 2 (AGO2)-associated miRNAs on laser-scanning confocal microscopy method was proposed to localize the miRNAs. But its definition was limited by the number of observed cells through its accuracy. Methods: In this study, a method based on imaging flow cytometry was developed to localize miR-590-5p with fluorescent probes in DCs. miR-590-5p proven to play an important role in tumor immunity. This method enabled the quantification, visualization and localization of the fluorescence intensity in 30,000 individual cells. Results: Using this method, the DCs with different endocytotic ability were distinguished. The behaviour of miR-590-5p during endocytosis under the stimulation of tumor antigen in DCs was observed, binding to its cognate target mRNA and degradation in DCs. Conclusion: This method based on imaging flow cytometry provide an additional method to study miRNA processing in DCs, which makes it a valuable addition to existing miRNA research techniques
关键词： miR-590-5p,miRNA endocytosis,Flow cytometry,Dendritic cells,Argonaute 2 (AGO2),FRET analysis
更新于2025-09-10 09:29:36
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Multiplexed determination of intracellular messenger RNA by using a graphene oxide nanoprobe modified with target-recognizing fluorescent oligonucleotides
摘要： A multiplexed graphene oxide (GO) fluorescent nanoprobe is described for quantification and imaging of messenger RNAs (mRNAs) in living cells. The recognizing oligonucleotides (with sequences complementary to those of target the fluorescence of the recognizing mRNAs) were labeled with different fluorescent dyes. If adsorbed on GO, oligonucleotides is quenched. After having penetrated living cells, the oligonucleotides bind to target mRNAs and dissociate from GO. This leads to the recovery of fluorescence. Using different fluorescent dyes, various intracellular mRNAs can be simultaneously imaged and quantified by a high content analysis within a short period of time. Actin mRNA acts as the internal control. This GO-based nanoprobe allows mRNA mimics to be determined within an analytical range from 1 to 400 nM and a detection limit as low as 0.26 nM. Up to 3 intracellular mRNAs (C-myc, TK1, and actin) can be detected simultaneously in a single living cell. Hence, this nanoprobe enables specific distinction of intracellular mRNA expression levels in cancerous and normal cells. It can be potentially applied as a tool for detection of cancer progression and diagnosis.
关键词： Fluorescence resonance energy transfer (FRET),Cancer biomarker,Actin mRNA,Fluorometric detection,High content analysis,Cancer diagnosis
更新于2025-09-10 09:29:36
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[Methods in Enzymology] Intrinsically Disordered Proteins Volume 611 || Accurate Transfer Efficiencies, Distance Distributions, and Ensembles of Unfolded and Intrinsically Disordered Proteins From Single-Molecule FRET
摘要： Intrinsically disordered proteins (IDPs) sample structurally diverse ensembles. Characterizing the underlying distributions of conformations is a key step toward understanding the structural and functional properties of IDPs. One increasingly popular method for obtaining quantitative information on intramolecular distances and distributions is single-molecule F?rster resonance energy transfer (FRET). Here we describe two essential elements of the quantitative analysis of single-molecule FRET data of IDPs: the sample-specific calibration of the single-molecule instrument that is required for determining accurate transfer efficiencies, and the use of state-of-the-art methods for inferring accurate distance distributions from these transfer efficiencies. First, we illustrate how to quantify the correction factors for instrument calibration with alternating donor and acceptor excitation measurements of labeled samples spanning a wide range of transfer efficiencies. Second, we show how to infer distance distributions based on suitably parameterized simple polymer models, and how to obtain conformational ensembles from Bayesian reweighting of molecular simulations or from parameter optimization in simplified coarse-grained models.
关键词： Intrinsically disordered proteins,Coarse-grained models,Conformational ensembles,Polymer models,Single-molecule FRET,Distance distributions,Bayesian inference
更新于2025-09-10 09:29:36
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Assessment of Gate Width Size on Lifetime-Based F?rster Resonance Energy Transfer Parameter Estimation
摘要： F?rster Resonance Energy Transfer (FRET) enables the observation of interactions at the nanoscale level through the use of fluorescence optical imaging techniques. In FRET, fluorescence lifetime imaging can be used to quantify the fluorescence lifetime changes of the donor molecule, which are associated with proximity between acceptor and donor molecules. Among the FRET parameters derived from fluorescence lifetime imaging, the percentage of donor that interacts with the acceptor (in proximity) can be estimated via model-based fitting. However, estimation of the lifetime parameters can be affected by the acquisition parameters such as the temporal characteristics of the imaging system. Herein, we investigate the effect of various gate widths on the accuracy of estimation of FRET parameters with focus on the near-infrared spectral window. Experiments were performed in silico, in vitro, and in vivo with gate width sizes ranging from 300 ps to 1000 ps in intervals of 100 ps. For all cases, the FRET parameters were retrieved accurately and the imaging acquisition time was decreased three-fold. These results indicate that increasing the gate width up to 1000 ps still allows for accurate quantification of FRET interactions even in the case of short lifetimes such as those encountered with near-infrared FRET pairs.
关键词： fluorescence lifetime,F?rster Resonance Energy Transfer (FRET),gated ICCD,near infrared (NIR) dyes,time-resolved imaging,gate width,in vivo imaging
更新于2025-09-10 09:29:36