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Handling Electromagnetic Radiation beyond Terahertz using Chromophores to Transition from Visible Light to Petahertz Technology
摘要： An increase of the operating frequencies of electromagnetic waves leads from the well-established terahertz technology to the visual and reaches petahertz radiation. It is shown that electromagnetic radiation close to petahertz is attractive for technology where knowledge about radio waves can be applied. The dimensions of such radiation are still classically macroscopic; however, molecular components such as resonators were used where quantum mechanics rules have to be considered. Constructions of coupled resonators for energy transfer are as well demonstrated as molecular components for optical metamaterials.
关键词： Dyes,FRET,Energy transfer,Reflectance,Petahertz,Visible light,Resonators,Metamaterials,Terahertz,Electromagnetic radiation
更新于2025-09-23 15:23:52
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Identification of Small-Molecule Modulators of Diguanylate Cyclase by FRET-Based High-Throughput Screening
摘要： The bacterial second messenger cyclic diguanosine monophosphate (c-di-GMP) is a key regulator of cellular motility, the cell cycle, and biofilm formation with its resultant antibiotic tolerance, which can make chronic infections difficult to treat. Therefore, diguanylate cyclases, which regulate the spatiotemporal production of c-di-GMP, might be attractive drug targets for control of biofilm formation that is part of chronic infections. We present a FRET-based biochemical high-throughput screening approach coupled with detailed structure–activity studies to identify synthetic small-molecule modulators of the diguanylate cyclase DgcA from Caulobacter crescentus. We identified a set of seven small molecules that regulate DgcA enzymatic activity in the low-micromolar range. Subsequent structure–activity studies on selected scaffolds revealed a remarkable diversity of modulatory behavior, including slight chemical substitutions that reverse the effects from allosteric enzyme inhibition to activation. The compounds identified represent new chemotypes and are potentially developable into chemical genetic tools for the dissection of c-di-GMP signaling networks and alteration of c-di-GMP-associated phenotypes. In sum, our studies underline the importance of detailed mechanism-of-action studies for inhibitors of c-di-GMP signaling and demonstrate the complex interplay between synthetic small molecules and the regulatory mechanisms that control the activity of diguanylate cyclases.
关键词： c-di-GMP,structure–activity relationships,FRET,diguanylate cyclase inhibitors,high-throughput screening
更新于2025-09-23 15:23:52
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A unique FRET approach toward detection of single-base mismatch DNA in BRCA1 gene
摘要： Early detection of mutation carriers in predisposing genes such as BRCA1 plays an important role in disease prevention. This work developed a quantum dots-based (QDs-based) fluorescence resonance energy transfer (FRET) technique for the detection of single-base mismatch DNA in BRCA1 gene. The FRET between QDs as the donor and silver nanocluster (AgNCs) as the acceptor was designed by the strong interaction between CdTe QDs with appropriate size and dsDNA through binding to its major groove. The dsDNA was formed by the hybridization of ssDNA labeled to AgNCs with target DNA, which introduced CdTe QDs into the major grooves to place the AgNCs in close proximity to the QDs. The complementary and single-base mismatch DNA led to obviously different FRET signals. The FRET signal linearly correlated to the concentration of single-base mismatch DNA in the range of 1.5 × 10^{-10}–1.0 × 10^{-6} mol L^{-1}. The proposed method showed a detection limit of 80 pmol L^{-1} and the sensitivity comparable to the previously reported assays, indicating promising potential for single nucleotide polymorphisms diagnosis in clinical application.
关键词： Silver nanocluster,DNA,Single-base mismatch,Quantum dots,FRET,Fluorescence analysis
更新于2025-09-23 15:23:52
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Ratiometric fluorescent probe based on pyrrole-modified rhodamine 6G hydrazone for the imaging of Cu2+ in lysosomes
摘要： A novel rhodamine-based Schiff base derivative was obtained via the simple condensation of substituted formyl-1H-pyrrole and rhodamine 6G hydrazone. Fluorescence resonance energy transfer enabled the subsequent use of the derivative as a naked-eye colorimetric and ratiometric fluorescent sensor for Cu2+ in semi-aqueous solution, and the existence of the morpholine group enabled the further application of the sensor in imaging Cu2+ in the lysosomes of HeLa cells.
关键词： ratiometric fluorescent probe,lysosome-targeting,rhodamine hydrazone,Cu2+,FRET,pyrrole
更新于2025-09-23 15:23:52
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Mitochondria-targeted and FRET based ratiometric fluorescent probe for SO2 and its cell imaging
摘要： SO2 can react with water to form sulphite (SO3 2-) and bisulphite (HSO3 -) ions, after it is inhaled into the body. Aberrant levels of SO2 and its derivatives in cells are related with a variety of diseases. So, it is important to monitor the level of SO2 and its derivatives in biological systems. Up to now, few probes have been reported for ratiometric detection of bisulfites in mitochondria. And the response speed of most reported probes were slow. It limited their application in real time detection of SO2. Here, using benzopyrylium as energy acceptor and mitochondria-targeted group, a FRET fluorescent probe CBP for SO2 was developed. CBP can detect SO2 with excellent selectivity over various analytes, including glutathione, homocysteine, cysteine and some common reactive oxygen species. The recognition process is accompanied by the color of the solution changing from purple to yellow, which allows “naked eye” detection for SO2. Its response is very fast (<1 min) and the detection limit is low (17.7 nM). In addition, probe CBP can be located in mitochondria and successfully used for the imaging of intracellular SO2 in EC-109 cells.
关键词： Fluorescence,Cell imaging,FRET,Ratiometric,Mitochondria
更新于2025-09-23 15:23:52
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Simultaneous Singlet–Singlet and Triplet–Singlet F?rster Resonance Energy Transfer from a Single Donor Material
摘要： For almost 70 years, F?rster resonance energy transfer (FRET) has been investigated, implemented into nowadays experimental nanoscience techniques, and considered in a manifold of optics, photonics and optoelectronics applications. Here, we demonstrate for the first time simultaneous and efficient energy transfer from both donating singlet and triplet states of a single photoluminescent molecular species. Using a biluminescent donor that can emit with high yield from both excited states at room temperature allows to apply the FRET framework to such a bimodal system. It serves as an exclusive model system where the spatial origin of energy transfer is exactly the same for both donating spin states involved. Of paramount significance are the facts that both transfers can easily be observed by eye and that F?rster theory is successfully applied to state lifetimes spanning over eight orders of magnitude.
关键词： organic light-emitting diodes,energy transfer,biluminescence,dual state FRET
更新于2025-09-23 15:23:52
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Photoswitching FRET to monitor protein–protein interactions
摘要： FRET is a powerful approach to study the interactions of fluorescent molecules, and numerous methods have been developed to measure FRET in cells. Here, we present a method based on a donor molecule's photoswitching properties, which are slower in the presence vs. the absence of an acceptor. The technique, photoswitching FRET (psFRET), is similar to an established but underutilized method called photobleaching FRET (pbFRET), with the major difference being that the molecules are switched 'off' rather than photobleached. The psFRET technique has some of the FRET imaging advantages normally attributed to fluorescence lifetime imaging microscopy (FLIM), such as monitoring only donor fluorescence. However, it can be performed on a conventional widefield microscope, requires less illumination light to photoswitch off than photobleaching, and can be photoswitched 'on' again to repeat the experiment. We present data testing the validity of the psFRET approach to quantify FRET in cells and demonstrate its use in imaging protein–protein interactions and fluorescent protein-based biosensors.
关键词： FRET,imaging,microscopy,photoswitchable,fluorescence
更新于2025-09-23 15:23:52
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An fluorescent aptasensor for sensitive detection of tumor marker based on the FRET of a sandwich structured QDs-AFP-AuNPs
摘要： The detection of alpha-fetoprotein (AFP) is of great importance for hepatocellular carcinoma (HCC) diagnosis, but it needs to be further improved because of poor sensitivity and complicated operating steps. In this paper, a simple and sensitive homogeneous aptasensor for AFP has been developed based on F?rster resonance energy transfer (FRET) where the AFP aptamer labeled luminescent CdTe quantum dots (QDs) as a donor and anti-AFP antibody functional gold nanoparticles (AuNPs) as an acceptor. In the presence of AFP, the bio-affinity between aptamer, target, and antibody made the QDs and AuNPs close enough, thus the fluorescence of CdTe QDs quenched though the FRET between QD and AuNP. The fluorescent aptasensor for AFP showed a concentration-dependent decrease of fluorescence intensity in the low nanomolar range and a detecting linear range of 0.5-45 ng mL?1, with a detection limit of 400 pg mL?1. Moreover, this homogeneous aptasensor is simple and reliable, and obtained satisfying results for the detection of AFP in human serum samples. With more and more aptamers for biomarkers have been selected gradually, this approach could be easily extended to detection of a wide range of biomarkers. The proposed aptasensor has great potential for carcinoma screening in point-of-care testing and even in field use.
关键词： alpha fetoprotein (AFP),fluorescent aptasensor,biomarker,hepatocellular carcinoma,F?rster resonance energy transfer (FRET)
更新于2025-09-23 15:23:52
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Lignosulfonate: a Convenient FRET Platform for the Construction of Ratiometric Fluorescence pH-Sensing Probe
摘要： Lignin is a kind of natural fluorescent polymer material. However, the application based on the fluorescent property of lignin was rarely reported. Herein, a non-covalent lignin-based Fluorescence Resonance Energy Transfer (FRET) system was readily constructed by physical blending method with spirolactam Rhodamine B (SRhB) and lignosulfonate (LS) as the acceptor and donor groups, respectively. The FRET behavior, self-assembly and energy transfer mechanism of SRhB/LS composite were systematically studied. It was demonstrated that LS could be used as a convenient aptamer as energy donor to construct water-soluble ratiometric sensors because of its inherent property of intra-micelle energy transfer cascades. Our results not only presented a facile and general strategy for producing lignin-based functional material, but also provided a fundamental understanding about lignin fluorescent to promote the functional and high-valued applications of lignin fluorescence characteristic.
关键词： lignin,ratiometric sensor,FRET,intra-micelle energy transfer cascade
更新于2025-09-23 15:23:52
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Accelerated FRET-PAINT microscopy
摘要： Recent development of FRET-PAINT microscopy significantly improved the imaging speed of DNA-PAINT, the previously reported super-resolution fluorescence microscopy with no photobleaching problem. Here we try to achieve the ultimate speed limit of FRET-PAINT by optimizing the camera speed, dissociation rate of DNA probes, and bleed-through of the donor signal to the acceptor channel, and further increase the imaging speed of FRET-PAINT by 8-fold. Super-resolution imaging of COS-7 microtubules shows that high-quality 40-nm resolution images can be obtained in just tens of seconds.
关键词： FRET-PAINT,Super-resolution fluorescence microscopy,FRET,Single-molecule localization microscopy
更新于2025-09-23 15:22:29