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Quantum Dots Improve Photovoltaic Properties of Purple Membranes under Near-Infrared Excitation
摘要： Purple membrane (PMs), in which the photosensitive protein bacteriorhodopsin (bR) naturally occurs, have photovoltaic properties and are promising for optoelectronic applications. However, PMs cannot effectively absorb light in the NIR spectral region. Semiconductor quantum dots (QDs), which have high two-photon absorption cross-sections in the NIR region, can significantly improve the light sensitivity of PMs by means of F?rster resonance energy transfer (FRET) from QDs to bR inside PMs. The purpose of this study was to improve the photovoltaic properties of PMs by means of FRET from QDs to bR under NIR two-photon excitation. We made the QD-PM complexes and showed high FRET efficiency in them. Finally, we found that the current signal from the QD-PM material was higher than that in the case of PMs alone under NIR excitation. The obtained results clearly demonstrate improvement of the photovoltaic properties of PMs under NIR two-photon excitation due to the FRET from QDs to bR and show the prospect of designing new photosensitive bio-nanohybrid devices.
关键词： Near-Infrared Excitation,F?rster Resonance Energy Transfer,Purple Membranes,Photovoltaic Properties,Quantum Dots
更新于2025-09-11 14:15:04
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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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Applied Nanophotonics || Energy transfer processes
摘要： In this chapter, we introduce the general phenomenon of excitation energy transfer, explain radiative and nonradiative types of energy transfer, and derive the basic processes of energy transfer. We look at the F?rster resonance energy transfer (FRET) in particular. We also describe Dexter energy transfer, charge transfer, exciton diffusion, and exciton dissociation. Finally, we summarize the modifications of FRET when using nanostructures with mixed dimensionalities and in different assemblies.
关键词： F?rster resonance energy transfer,nanostructures,FRET,charge transfer,exciton diffusion,energy transfer,Dexter energy transfer,exciton dissociation
更新于2025-09-10 09:29:36
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Energy Transfer from CdSe/ZnS Nanocrystals to Tetraphenyl Porphyrin
摘要： CdSe/ZnS nanocrystals (NCs) and Tetraphenyl Porphyrin (TPP) are mixed uniformly to prepare CdSe/ZnS NCs/TPP complex. TPP can quench the fluorescent signal of CdSe/ZnS NCs. UV-Vis absorption spectra and fluorescence spectra are employed to analysis the energy transfer. The mechanism of energy transfer is the F?rster resonance energy transfer from CdSe/ZnS to TPP.
关键词： Tetraphenyl Porphyrin,energy transfer,CdSe/ZnS nanocrystals,F?rster resonance energy transfer
更新于2025-09-10 09:29:36
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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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A multicolor large Stokes shift fluorogen-activating RNA aptamer with cationic chromophores
摘要： Large Stokes shift (LSS) fluorescent proteins (FPs) exploit excited state proton transfer pathways to enable fluorescence emission from the phenolate intermediate of 4-hydroxybenzylidene imidazolone (HBI) chromophore. An RNA aptamer named Chili mimics LSS FPs by inducing highly Stokes-shifted emission from several new green and red HBI analogs that are non-fluorescent when free in solution. The ligands are bound by the RNA in their protonated phenol form and feature a cationic aromatic side chain for increased RNA affinity and reduced magnesium dependence. In combination with oxidative functionalization at the C2 position of the imidazolone, this strategy yielded DMHBO+, which binds to the Chili aptamer with a low-nanomolar KD. Because of its highly red-shifted fluorescence emission at 592 nm, the Chili–DMHBO+ complex is an ideal fluorescence donor for F?rster resonance energy transfer (FRET) to the rhodamine dye Atto 590 and will therefore find applications in FRET-based analytical RNA systems.
关键词： RNA aptamer,fluorescence,fluorescence resonance energy transfer,fluorescent protein,large Stokes shift
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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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
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Using optical tweezers to construct an upconversion luminescent resonance energy transfer analytical platform
摘要： We report a new upconversion nanoparticles (UCNPs) based luminescent resonance energy transfer (LRET) analytical platform by making use of optical tweezers technology. The LRET model is designed by simultaneously conjugating Yb3+ and Er3+ co-doped UCNPs (as the donors) and tetramethyl rhodamine (TAMRA) molecules (as the acceptors) on microspheres to fabricate complex microspheres. Upon a single complex microsphere entering the three-dimensional potential well formed with a tightly focused 980 nm Guassian-shaped laser beam, it is optically trapped and concurrently the upconversion emission is excited, whereby the donor signals are transferred to the acceptors. As a proof-of-concept investigation, microRNA-21 sequences are selected as the targets, by which the distance between the two perfectly matched luminophors is controlled to several nanometers via nucleic acid hybridization. Without the involvement of luminescence amplification strategies, the proposed single microsphere based LRET method shows highly competitive sensitivity with a limit of detection down to 114 fM and satisfactory specificity towards microRNAs detection. Moreover, its practical working ability is demonstrated by credibly quantifying the absolute contents of miRNA-21 sequences in three cancer cell lines and even tracing the targets in as few as 100 cancer cells. Thus, this favorable analytical methodology provides an alternative for bioassays and holds certain potential in biomedical applications.
关键词： microRNA detection,Upconversion nanoparticle (UCNPs),Luminescent resonance energy transfer (LRET),Optical tweezers
更新于2025-09-10 09:29:36