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Trichromophore-doped cassava-based biopolymer as low-cost and eco-friendly luminous material for bio hybrid white-light-emitting diodes by dual-FRET process
摘要： White-light-emitting diodes (WLEDs) are promoted as environmentally friendly because they are energy saving-features and mercury-free aspects, but, rare-earth-free, metal-free, cost-competitive, and eco-friendly for brighter WLEDs are attractive but quite challenging in practice. This paper reports a new methodology using biopolymer luminous material in bio hybrid white-light-emitting diodes (Bio-HWLEDs) based on a trichromophore-doped cassava crystalline thick film that emits bright white light emission through a dual F?rster resonance energy transfer (FRET) process. The dual-FRET takes place from coumarin to sulforhodamine via the curcumin chromophore. The Bio-HWLED showed color co-ordinates (0.33, 0.32) that exactly matched with pure white light emission. The effect of temperature on luminescence and the activation energy for thermal quenching were determined using the temperature-dependent photoluminescence measurements. Moreover, Bio-HWLED showed a low luminous drop rate of 0.00069 s?1 to overcome the aggregation-induced quenching effect. These results pave the way towards the realization of commercially viable, large-scale and high-contrast bio hybrid light applications that are environmentally friendly.
关键词： Chromophore,Cassava,Bio-LEDs,Dual-FRET,Quenching effect
更新于2025-09-16 10:30:52
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Exploring dynamics of resonance energy transfer in hybrid Quantum Dot Sensitized Solar Cells (QDSSC)
摘要： Graphene based nanomaterials are known to provide new avenues to improve semiconductor based light harvesting devices. This work makes use of graphene quantum dots (GQD) to improve the efficiency of a CdSe Quantum Dot Sensitized Solar Cell (QDSSC) by F?rster Resonance Energy Transfer (FRET) mechanism. FRET describes non-radiative energy transfer between two adjacent molecules typically in range from 1 to 10 nm with one molecule as donor and other molecule as acceptor. If the acceptor is in close proximity of the excited donor, then their dipoles align resulting in transfer of excitation energy from donor to acceptor. Here graphene quantum dot acts as the energy donor to enhance light harvesting of CdSe quantum dot which acts as an acceptor in the hybrid solar cell. The introduction of GQD increases the efficiency of CdSe sensitized QDSSC from 0.18 to 0.28% showing an efficiency enhancement of 55%. The improved efficiency is mainly attributed to the 46% increase in current density of the GQD-CdSe solar cell compared to the CdSe QDSSC. The increased performance of the QDSSC owes to the existence of non-radiative energy transfer (FRET) between GQD and CdSe evident from photoluminescence (PL) quenching and lifetime measurements. This FRET system of GQD (donor)-CdSe (acceptor) shows an energy transfer of 48.7% providing new insights for selective light harvesting of the solar spectrum which can be utilised for various potential applications in future.
关键词： donor,QDSSC,FRET,acceptor
更新于2025-09-16 10:30:52
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Application of maleimide modified graphene quantum dots and porphyrin fluorescence resonance energy transfer in the design of a??a??turn-ona??a?? fluorescence sensors for biothiols
摘要： Two novel fluorescent probes were designed to detect the biothiol in foods using the highly efficient Michael addition reaction between maleimide-derived probes and the biothiol. First, maleimide functionalized GQDs (M-GQDs) were synthesized and used for biothiol identification according to the Michael addition principle. The biothiol can be detected in the range of 5× 10-9 to 4× 10-7 mol/L and the detection limit was 1.69×10-9 mol/L. Then, a fluorescence resonance energy transfer (FRET) system between M-GQDs and tetrakis (4-aminophenyl) porphyrin (TAPP) for biothiol detection was developed. However, the process of FRET was switched off in the presence of biothiols due to the switch of M-GQDs fluorescence emission to the“ON” mode following the Michael addition mechanism. The system could quickly and accurately detect the biothiol with a detection range of 6.7×10-10 to 2×10-7 mol/L and a detection limit of 2.34×10-10 mol/L. Compared to the single detection system, the FRET system had a wider detection range and lower detection limit, and the related biomolecules did not interfere with the quantitative identification of the biothiol. The proposed method was successfully applied for the determination of the biothiol in foods and human blood samples.
关键词： Porphyrin,Fluorescence “turn-on”,Biothiols,FRET,Graphene quantum dots
更新于2025-09-16 10:30:52
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Conjugated Polymer-Quantum Dot Hybrid Materials for Pathogen Discrimination and Disinfection
摘要： In this work, a new platform for pathogen discrimination and killing based on a conjugated polymer-quantum dot hybrid material was designed and constructed through the fluorescence resonance energy transfer (FRET) process. The hybrid material comprises water-soluble anionic CdSe/ZnS quantum dots (QDs) and a cationic poly(fluorene-alt-phenylene) derivative (PFP) through electrostatic interactions, thus promoting efficient FRET between PFP and QDs. Upon addition of different pathogen strains, the FRET from PFP to QDs was interrupted because of the competitive binding between PFP and the pathogens. Complexation of PFP and QDs also reduced the dark toxicity to a more desirable level, therefore potentially realizing the controllable killing of pathogens. The technique provides a promising theranostic platform in pathogen discrimination and disinfection based on FRET and phototoxicity of the PFP and QDs.
关键词： FRET,pathogens discrimination and killing,quantum dots,conjugated polymers,theranostic platform
更新于2025-09-12 10:27:22
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Modified CdS quantum dots as selective turn-on fluorescent nanosensor for detection and determination of methamphetamine
摘要： Surface modification of cadmium sulfide quantum dots (CdS-QDs) with anti-methamphetamine (anti-METH) antibody produced a new turn-on fluorescent nanosensor, anti-METH-CdS-QDs, for detection of methamphetamine. The anti-METH-CdS-QDs nanosensor was obtained readily via the covalent conjugation of mercaptoacetic acid capped CdS-QDs with anti-METH in the presence of N-ethyl-N′-(3-dimethylaminopropyl carbodiimide) (EDC) and Sulfo-N-hydroxysuccinimide (Sulfo-NHS) as coupling agents. The results of FT-IR and energy dispersive X-ray (EDX) spectroscopies confirmed the functionalization of CdS-QDs with anti-METH species. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses revealed the crystal phase and microstructure of CdS-QDs in the anti-METH-CdS-QDs. The obtained anti-METH-CdS-QDs exhibited fluorescence enhancement upon addition of methamphetamine molecules which allowed the highly sensitive and selective determination of methamphetamine with detection limit of 0.006 mg/L. Further studies disclosed that this nanosensor has little interaction with other drugs such as codeine and ibuprofen. Hence, it can be utilized as simple, inexpensive, and selective nanosensor for determination of methamphetamine in low concentrations.
关键词： FRET mechanism,Methamphetamine,Anti-METH antibody,Fluorescent nanosensor,CdS quantum dots
更新于2025-09-12 10:27:22
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The in vivo mechanics of the magnetotactic backbone as revealed by correlative FLIM-FRET and STED microscopy
摘要： Protein interaction and protein imaging strongly benefit from the advancements in time-resolved and superresolution fluorescence microscopic techniques. However, the techniques were typically applied separately and ex vivo because of technical challenges and the absence of suitable fluorescent protein pairs. Here, we show correlative in vivo fluorescence lifetime imaging microscopy F?rster resonance energy transfer (fLiM-fRet) and stimulated emission depletion (SteD) microscopy to unravel protein mechanics and structure in living cells. We use magnetotactic bacteria as a model system where two proteins, MamJ and MamK, are used to assemble magnetic particles called magnetosomes. The filament polymerizes out of MamK and the magnetosomes are connected via the linker MamJ. Our system reveals that bacterial filamentous structures are more fragile than the connection of biomineralized particles to this filament. More importantly, we anticipate the technique to find wide applicability for the study and quantification of biological processes in living cells and at high resolution.
关键词： FLIM-FRET,living cells,magnetotactic bacteria,STED microscopy,protein mechanics
更新于2025-09-12 10:27:22
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Photo-controlled chirality transfer and FRET effects based on pseudo[3]rotaxane
摘要： The use of light to regulate the chirality of supramolecular assemblies in a non-invasive manner remains a challenge. Herein, we report a novel photochromic pseudo[3]rotaxane based on a (R/S)-2,20-binaphthyl secondary ammonium salt guest (2) and anthracene-bridged bis(dibenzo-24-crown-8) (1), which features a chirality transfer and fluorescence resonance energy transfer (FRET) from 2 to 1. Benefiting from the photo-oxidation of anthracene, the induced circular dichroism (ICD) signals of (R/S)-2@1 can be switched off/on by irradiation with 365 nm UV light and heating. This noncovalent supramolecular assembly strategy provides us with unique opportunities to design and construct further smart photo-responsive chiral molecular switches.
关键词： circular dichroism,supramolecular assemblies,FRET,chirality transfer,photo-oxidation
更新于2025-09-12 10:27:22
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Reversibly Photoswitchable Dual-Color Fluorescence and Controlled Release Properties of Polymeric Nanoparticles
摘要： Here, we report a novel polymeric nanoparticle prepared by the self-assembly of amphiphilic copolymers containing a ?uorescent naphthalimide (NAPH) and a photochromic spiropyran (SP), which possesses reversibly photoswitchable dual-color ?uorescence and controlled release properties. The amphiphilic copolymers were synthesized by incorporating NAPH and SP into methyl ether poly(ethylene glycol)-poly(β-amino esters) (MPEG-PAE) via quaternization. The nanoparticles would change between yellow and purple reversibly upon UV and visible light irradiation because of the photoisomerization between SP and merocyanine (MC). The corresponding ?uorescence would be switched between green and orange-red reversibly upon blue light excitation through the ?uorescence resonance energy transfer from the excited NAPH to the photoisomerized MC. Meanwhile, the prepared spherical nanoparticles could be swollen under UV irradiation as the hydrophobic SP isomerized to hydrophilic MC; the nanoparticles could also be swollen under acidic conditions because of the protonation of the amino groups of PAE. Upon UV light irradiation and acidic stimulation, the cargoes, hydrophobic Coumarin 102, encapsulated in the nanoparticles would be released. The prepared nanoparticles, which exhibit not only excellent reversible dual-color ?uorescence properties but also prominent controlled release performance, will open up new possibilities for the combined application of ?uorescence imaging and controlled release.
关键词： naphthalimide,Coumarin 102,spiropyran,polymeric nanoparticles,photoswitchable,amphiphilic copolymers,acidic conditions,quaternization,self-assembly,FRET,UV/vis light irradiation,dual-color ?uorescence,MPEG-PAE,controlled release
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Toward Coupling Color Centers in Single Crystal Diamond to Two-Dimensional Materials
摘要： Individual nitrogen vacancy (NV) color centers in diamond are bright, photo-stable, atomic-sized dipole emitters [1]. Consequently, they represent optimal candidates for novel scanning near field microscopy techniques [2]. Here, NV centers form one member of a F¨orster Resonance Energy Transfer (FRET) pair. Due to their broadband emission (> 100 nm), NVs are versatile donors for FRET to systems absorbing in the near infrared spectral range. Highly-promising applications include, e.g., nanoscale imaging of fluorescent molecules or nanomaterials like graphene [2]. Critical parameters for FRET are the NV’s quantum efficiency, charge state stability and NV-sample-distance. Previous experiments used NVs in nanodiamond for FRET [2], however these NVs might suffer from quenching, instability and badly controlled surface termination. We here address this issue by using shallowly implanted NV centers in optimized cylindrical nanostructures [3] used as scanning probes in our homebuilt combination of a confocal and an atomic force microscope. In recent years, two-dimensional materials especially monolayers of semiconducting materials are of major interest in research. Particularly, dichalcogenides like, e.g., tungsten diselenide (WSe2) are promising candidates for a varity of applications [4]. WSe2 emits photons at a wavelength of around 750 nm while absorbing photons below 700 nm [4] which renders WSe2 as a promising FRET partner for NV centers. Here, we present first results towards demonstrating the interaction of NV color centers in single crystal diamond with WSe2. We envisage using quenching of the NV center sued as a donor in FRET in close proximity to the 2D material as a valuable sensing ressource.
关键词： F¨orster Resonance Energy Transfer (FRET),tungsten diselenide (WSe2),nitrogen vacancy (NV) color centers,diamond,two-dimensional materials
更新于2025-09-11 14:15:04
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Genetically encoded FRET-based optical sensor for Hg2+ detection and intracellular imaging in living cells
摘要： Due to the potential toxicity of mercury, there is an immediate need to understand its uptake, transport and flux within living cells. Conventional techniques used to analyze Hg2+ are invasive, involve high cost and are less sensitive. In the present study, a highly efficient genetically encoded mercury FRET sensor (MerFS) was developed to measure the cellular dynamics of Hg2+ at trace level in real time. To construct MerFS, the periplasmic mercury-binding protein MerP was sandwiched between enhanced cyan fluorescent protein (ECFP) and venus. MerFS is pH stable, offers a measurable fluorescent signal and binds to Hg2+ with high sensitivity and selectivity. Mutant MerFS-51 binds with an apparent affinity (Kd) of 5.09 × 10?7 M, thus providing a detection range for Hg2+ quantification between 0.210?μM and 1.196?μM. Furthermore, MerFS-51 was targeted to Escherichia coli (E. coli), yeast and human embryonic kidney (HEK)-293T cells that allowed dynamic measurement of intra- cellular Hg2+ concentration with a highly responsive saturation curve, proving its potential application in cellular systems.
关键词： Genetically encoded,FRET,Fluorescent proteins,Mercury,Nanosensors
更新于2025-09-11 14:15:04