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Green Fluorescent Protein-Based Glucose Indicators Report Glucose Dynamics in Living Cells
摘要： Glucose is the most important energy source for living animals. Here, we developed a series of single fluorescent protein (FP)-based glucose indicators, named as "Green Glifons", to understand the hierarchal and mutual relationships between molecules involved in energy metabolism. Three indicators showed a different EC50 for glucose (50 μM, 600 μM and 4,000 μM), producing a ~7-fold change in fluorescence intensity in response to glucose. The indicators could visualize glucose dynamics in the cytoplasm, plasma membrane, nucleus and mitochondria of living HeLa cells and in vivo, in the pharyngeal muscle of C. elegans and could measure murine blood glucose levels. Finally, the indicators were applicable to dual-color imaging, revealing the dynamic interplay between glucose and Ca2+ in mouse pancreatic MIN6 m9 β cells. We propose that these indicators will facilitate and contribute to in vivo and multi-color imaging of energy metabolism.
关键词： biosensors,artificial sweeteners,dual-color imaging,C. elegans,live cell imaging,glucose,blood glucose level,fluorescent protein
更新于2025-11-21 11:24:58
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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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Wnt signaling induces neurite outgrowth in mouse retinal ganglion cells
摘要： Wingless-type (Wnt) signaling pathways mediate axonal growth and remodeling in the embryonic optic nerve, brain and spinal cord. Recent studies demonstrated that the canonical Wnt/β-catenin signaling pathway also induces axonal regeneration after injury in the optic nerve of adult animals. However, the molecular mechanisms of Wnt-mediated axonal growth are not well understood. Additionally, because Wnt signaling is stimulated in neurons as well as neighboring non-neuronal cells, the cell type(s) responsible for Wnt-induced axonal regeneration are not known. The objectives of this study were to investigate potential mechanisms and target cells of Wnt3a stimulated neurite growth using primary retinal ganglion cell (RGC) cultures. We demonstrated that Wnt3a ligand induced dose-dependent increases in average neurite length and number of neurites in RGCs. QPCR analysis of candidate mediators showed that Wnt3a-dependent neurite growth was associated with lower expression of Ripk1 and Ripk3 genes. Additionally, inhibiting Ripk1 signaling with Necrostatin-1s led to increased neurite number per cell but not increased neurite length. Therefore, Ripk signaling may be involved in mediating the effects of Wnt3a on neurite number but Ripk activity does not seem to be required for Wnt3a-dependent regulation of neurite length. This study shows that RGCs are direct cellular targets of Wnt3a-induced axonal growth, and we identified a novel association between Wnt signaling and Rip kinases in neurite formation.
关键词： retina,Ripk1,axon,retinal ganglion cell,neurite growth,Wnt signaling
更新于2025-11-21 11:24:58
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Gaussian FRET two-hybrid assays for determining the stoichiometry of hetero-oligomeric complexes in single living cells
摘要： Here we integrate multiple Gaussian-functions analysis into fluorescence resonance energy transfer (FRET) two-hybrid assays (Gaussian FRET two-hybrid assay) to determine the stoichiometric ratios of intracellular hetero-oligomers in single living cells. This method adopts in multiple Gaussian-functions to fit the E-count histograms of both donor- and acceptor-centric FRET efficiency (ED and EA) images of a single cell for obtaining the peak values (EDi and EAi), thus yielding the corresponding stoichiometric ratios (EDi/EAi) of intracellular hetero-oligomers. We performed Gaussian FRET two-hybrid assay for living Hela cells coexpressing different FRET tandem plasmids, and obtained consistent results with the expected values. Gaussian FRET two-hybrid assay for cells coexpressing Bad-CFP and Bcl-XL-YFP reveals that Bcl-XL binds with Bad to form a hetero-oligomeric complex with a stoichiometry of 2:1 on mitochondria.
关键词： Multiple Gaussian-functions analysis,FRET imaging,Single living cell,Stoichiometry,Hetero-oligomeric complex
更新于2025-11-21 11:24:58
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Influence of RbF post deposition treatment on heterojunction and grain boundaries in high efficient (21.1%) Cu(In,Ga)Se2 solar cells
摘要： Post deposition treatments (PDT) by alkali fluorides applied to chalcopyrite-based absorbers have produced record efficiencies in thin-film solar devices in the past few years and recently the efficiency of 22.6 % was achieved with Cu(In,Ga)Se2 (CIGS) using rubidium fluoride (RbF) PDT. However, the effects of RbF-PDT towards changes in its interfacial and grain boundary (GB) properties are still not fully understood. In this work, cells with efficiency higher than 21% are investigated by combination of atom probe tomography (APT) and transmission electron microscopy (TEM) to show how changes in GB and interface chemistry may facilitate high efficiencies. APT studies, carried out at the interface between CIGS absorber and solution-grown CdS buffer layer, show In enrichment and Cu depletion along with traces of Rb. Our APT studies reveal higher amounts of Rb (1.5 at. %) and lower amounts of Na and K (<0.5 at. %) at GBs as compared with previous studies (on non-PDT samples) thus indicating substitution of Na and K by Rb. However, concentration of all alkali elements inside the grain bulk is below detection limit of APT. The concentration of Rb at the GBs in CIGS is measured depth-dependent using both APT and TEM, which consistently shows the increase in Rb towards the Mo back contact. In addition, a pronounced Cu depletion is observed at the GBs which might enhance hole-barrier properties of the GBs, thus improving charge carrier collection and hence the overall efficiency of the device. Thus, understanding effects of RbF-PDT at the atomic scale provides new insights concerning the further improvement of CIGS absorber and interfaces.
关键词： Cu(In,Ga)Se2,Thin-film solar cell,heterojunction,atom probe tomography,post deposition treatments,transmission electron microscopy
更新于2025-11-21 11:20:48
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Electric field assisted spray coated lead free bismuth iodide perovskite thin film for solar cell application
摘要： Solution-processed Methylammonium iodo bismuthate (MBI) perovskite solar cell is fabricated by spray technique with changed applied voltages from 0 to 1000 V during the deposition of MBI thin film. The morphology and surface roughness of MBI films are influenced significantly by the electric field during film deposition. It is attributed to improve the atomization of spray droplets due to process of coulomb fission. The surface roughness of MBI film is reduced from 39 to 19 nm with increased applied voltages during the deposition from 0 V and 1000 V, respectively. A strong absorption band is observed ～500 nm for all MBI films. The MBI perovskite solar cell is showed enhancement in the efficiency with the maximum current density 2.33 mA/cm2 at 1000 V applied voltage during the deposition. The improvement in photovoltaic characteristics with applied voltage during the film deposition is attributed to the formation of more uniform film with improved surface morphology and roughness, resulting in efficient electron transfer and reduced recombination of charge carrier at grain boundaries.
关键词： Methyl ammonium bismuth (III) iodide,Spray deposition,Perovskite solar cell,Electric filed,Lead free perovskite
更新于2025-11-21 11:18:25
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Enhanced working efficiency of Si solar cell by water induced nano-porous thermal cooling layer
摘要： Nano-porous thermal cooling layer (TCL) of thickness 14 mm beneath a Si solar cell reduces its working temperature from 82 °C to 68 °C This reduced working temperature increase its absolute working ef?ciency by 0.75%. X-Ray diffraction analysis of the material used in TCL shows its amorphous nature. The SEM images con?rm interconnected carbon particles are forming micro-channels within the TCL. Further FESEM analysis has been done to examine the in-depth structure of the carbon particles and shows the nano-porous topography within the particle. The porosity of used TCL is examined by BET measurement which con?rms the highly porous nature of the TCL having surface area of the order of 798.35 m2 g?1 with average pore size of 2.3 nm. The induced water concentration (0.049 to 0.49 ml cm?3) dependent enhanced cooling ef?ciency of nano-porous TCL has been studied in detail. The use of water saturated (0.49 ml cm?3) TCL (14 mm thick) further decreases the working temperature of the device from 68 °C to 58 °C and the device works below this temperature for around three hours. Further, in order to enhance the effective time duration, the TCL thickness (4 mm to 26 mm) dependent cooling ef?ciency of water saturated TCL has been analyzed in detail. Use of optimized water saturated TCL beneath the solar cell improve its working ef?ciency from 11.4% (at 82 °C) to 12.69% (at 58 °C) which shows an absolute and relative enhancement of 1.29% and 11.32%, respectively in cell ef?ciency. Finally, thermal analyses of TCL and water cooling mechanism in it have been discussed in detail.
关键词： ef?ciency enhancement,Si solar cell,thermal cooling layer,cooling plateau,cooling agent,nano-porous
更新于2025-11-21 11:18:25
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A carbon nanotube-iron (III) oxide nanocomposite as a cathode in dye-sensitized solar cells: Computational modeling and electrochemical investigations
摘要： Here is the evaluating result on the applicability of the multi-walled carbon nanotube (MWCNT) and a-iron (III) oxide (a-Fe2O3) nanocomposite as a cathode material in dye-sensitized solar cells (DSCs). The morphology and the structure of the MWCNT/a-Fe2O3 nanocomposite have characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray elemental mapping analysis. Moreover, the electrochemical performance of the nanocomposite has studied toward the activity of Iˉ/I3ˉ redox couple which represents high current density, low peak-to-peak separation, low charge-transfer resistance, and almost 100% stable response signal. Furthermore, the computational modeling employing the molecular mechanics (MM) and the restricted-Hartree Fock/semiempirical parameterization (RHF/PM6) methods reveals that the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and the HOMO-LUMO energy gap of the modeled nanocomposite are as (cid:1)6.88, (cid:1)3.62, and 3.26 eV, respectively. These properties match with the electronic-level domino of the DSC structure. Finally, the DSC device has fabricated using N719-sensitized TiO2 photoanode and MWCNT/a-Fe2O3 counter electrode, presenting the open-circuit potential, the short-circuit current density, and the power-conversion ef?ciency of 0.7 V, 20.37 mA cmˉ2, and 6.0%, respectively. This study successfully approves the potential of the nanocomposite as a cathode material in iodine-based dye-sensitized solar cells.
关键词： Dye-sensitized solar cell,Nanocomposite,Carbon nanotube,Molecular mechanics,RHF/PM6,Iron (III) oxide
更新于2025-11-21 11:18:25
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Laser‐Assisted Strain Engineering of Thin Elastomer Films to Form Variable Wavy Substrates for Cell Culture
摘要： Endothelial and epithelial cells usually grow on a curved environment, at the surface of organs, which many techniques have tried to reproduce. Here a simple method is proposed to control curvature of the substrate. Prestrained thin elastomer films are treated by infrared laser irradiation in order to rigidify the surface of the film. Wrinkled morphologies are produced upon stress relaxation for irradiation doses above a critical value. Wrinkle wavelength and depth are controlled by the prestrain, the laser power, and the speed at which the laser scans the film surface. Stretching of elastomer substrates with a “sand clock”-width profile enables the generation of a stress gradient, which results in patterns of wrinkles with a depth gradient. Thus, different combinations of topography changes on the same substrate can be generated. The wavelength and the depth of the wrinkles, which have the characteristic values within a range of several tens of μm, can be dynamically regulated by the substrate reversible stretching. It is shown that these anisotropic features are efficient substrates to control polarization of cell shapes and orientation of their migration. With this approach a flexible tool is provided for a wide range of applications in cell biophysics studies.
关键词： cell curvotaxis,laser treatment,curvature,dynamic substrates,strain engineering
更新于2025-11-21 11:08:12
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A fluorescent probe based on tetrahydro[5]helicene derivative with large Stokes shift for rapid and highly selective recognition of hydrogen sulfide
摘要： In this work, we have designed and synthesized a dinitrobenzene-sulfonate tetrahydro[5]helicene (H-DNP) as an effective fluorescent probe for detection of hydrogen sulfide (H2S). Upon the addition of H2S, a significant fluorescence enhancement (75-fold) at 495 nm can be observed with a distinct color change from colorless to yellow. Additionally, H-DNP shows low background spectroscopic signal, large Stokes Shift up to ~140 nm, good sensitivity, rapid response time less than 2 min, low detection limit (48 nM) and high selectivity towards common bio-thiols (Cysteine, Homocysteine and Glutathione). Compared with the previous dinitrophenoxy tetrahydro[5]helicene, this probe has shorter response time and lower detection limit. Most importantly, this probe H-DNP has low toxicity to cells and excellent cell permeability, which can be applied to visualize H2S in living cells.
关键词： Fluorescence,Cell imaging,Probe,4-dinitrobenzene,Helicene,2,Hydrogen sulfide
更新于2025-11-21 11:08:12