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Optical Band Gap, Local Work Function and Field Emission Properties of MBE Grown β-MoO3 Nanoribbons
摘要： Monoclinic molybdenum trioxide (β-MoO3) nanostructures (shaped like nanoribbons: NRs) were grown on Si(100), Si(5512) and fluorine-doped tin oxide (FTO) by molecular beam epitaxy (MBE) technique under ultra-high vacuum (UHV) conditions. The dependence of substrate conditions and the effective thickness of MoO3 films on the morphology of nanostructures and their structural aspects were reported. The electron microscopy measurements show that the length and the aspect ratio of nanostructures increased by, 260% without any significant change in the width for a change in effective thickness from 5 nm to 30 nm. NRs are grown along <011> for all the effective thickness of MoO3 films. Similarly, when we increased the film thickness from 5 nm to 30 nm, the optical band gap decreased from 3.38± 0.01eV to 3.17± 0.01eV and the local work function increased from 5.397 ± 0.025 eV to 5.757 ± 0.030 eV. Field emission turn-on field decreased from 3.58 V/μm for 10-μA/cm2 to 2.5 V/μm and field enhancement factor increased from 1.1×104 to 5.9×104 for effective thickness variation of 5 nm to 30 nm β-MoO3 structures. The β-MoO3 nanostructures found to be much better than the α-MoO3 nanostructures due to low work function, low turn on field and high field enhancement factor, and are expected to be useful applications.
关键词： β-MoO3 nanostructures,Field emission and Kelvin probe force microscopy (KPFM),Optical band gap,Molecular beam epitaxy (MBE),Electron microscopy
更新于2025-09-23 15:22:29
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Ratiometric fluorescence imaging for sodium selenite in living cells
摘要： Sodium selenite as a common selenium-containing agent has been extensively studied for human health, especially cancer prevention and treatment. However, precisely evaluating the dynamic changes of sodium selenite at cellular and molecular level in these pharmacological and pathophysiological studies is still challenging. Developing the chemical tools that enable the quantification of sodium selenite in vivo with high spatial and temporal fidelity thus can provide an efficient solution to this challenge. Here, we report the design, synthesis and biological evaluation of ratiometric sodium selenite fluorescent probe (HBTN-Se) for quantitative ratiometric fluorescence imaging of sodium selenite concentration fluctuations in living cells. A strategy for sodium selenite quantification has been achieved effectively through using a highly selective, rapid and biocompatible hydroxyl-deprotecting reaction. The ratiometric fluorescence imaging with HBTN-Se is constructed to precisely monitor changes in sodium selenite levels in living cells. Moreover, HBTN-Se is capable of visualizing differences in sodium selenite levels between normal cells and cancer cells, establishing the utility of this ratiometric detection platform for assessing the correlation between physiological effects of sodium selenite and its levels in living cells.
关键词： Quantitative determination,Fluorescent probe,Sodium selenite,Ratiometric fluorescence imaging
更新于2025-09-23 15:22:29
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Metal nanowire–polymer matrix hybrid layer for triboelectric nanogenerator
摘要： In this work, we studied the surface potential of a metal–polymer hybrid layer and its effect on the performance of a triboelectric nanogenerator (TENG). Ag nanowires (AgNWs) separately embedded in two different polymers–one with a positive tribopotential and the other with a negative tribopotential–were prepared as model hybrid systems. The surface potentials of the hybrid system were systematically investigated by Kelvin probe force microscopy. The results demonstrated that each component of the hybrid layer affected the other component because of the difference in their work functions. The following two important findings were obtained. First, the surface potential of each polymer shifted drastically toward that of Ag and the surface potential of Ag shifted toward that of each polymer. Second, higher density of AgNWs led to higher Ag-induced charge density in the polymer, which consequently resulted in larger shift in the surface potential of the polymer. TENG performance measurements revealed that the tribopotential difference between the contact surfaces of the AgNW–polymer hybrid layer and the perfluoroalkoxy alkane (or Nylon) used as the top triboelectric layer governed the TENG performance. Our systematic investigation of the surface potential of a hybrid surface consisting of two materials with different surface potentials provides insight into the design of triboelectric layers for high-performance TENGs.
关键词： triboelectric nanogenerator,silver nanowire,kelvin probe force microscopy,hybrid,surface potential
更新于2025-09-23 15:22:29
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A high-performance fluorescent probe for dopamine detection based on g-C3N4 nanofibers
摘要： A novel fluorescent sensor based on g-C3N4 nanofibers for the sensitive detection of dopamine (DA) has been proposed. We synthesized g-C3N4 nanofibers by directly hydrolyzing bulk g-C3N4 in the alkaline atmosphere (3 M NaOH). The obtained ultrathin g-C3N4 nanofibers were verified by characterizations of Transmission electronic microscope (TEM), X-ray diffractometer (XRD), Fourier transformation-infrared (FT-IR) and X-Ray photoelectron spectroscopy (XPS). It was found that the fluorescence intensity of g-C3N4 nanofibers was obviously quenched by DA. Fluorescence resonance energy transfer (FRET) between DA and g-C3N4 nanofibers led to the fluorescence reduction of g-C3N4 nanofibers. The fluorescent probe based on g-C3N4 nanofibers exhibits linear responses to the concentration of DA in the range from 0 to 4 μM and 4 to 20 μM, the limit of detection is 17 nM. The fluorescent probe shows excellent stability, good selectivity with its application in serums.
关键词： dopamine,g-C3N4 nanofibers,quenching,fluorescent probe
更新于2025-09-23 15:22:29
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A novel “turn-on” mitochondria-targeting near-infrared fluorescent probe for H2S detection and in living cells imaging
摘要： Hydrogen sulfide (H2S) has been considered to be involved in cytoprotective processes and redox signaling. It is very meaningful to track and analyze it in mitochondria. Herein, we report a novel “turn-on” mitochondria-targeting near-infrared fluorescent probe (Mito-NIR-SH) for detection of H2S in living cells, which was designed and synthesized by introducing 2,4-dinitrophenyl as fluorescence quenching group and H2S response moiety into Changsha near-infrared fluorophore (CS-OH). The structure of the fluorophore and the probe were characterized by 1H NMR, 13C NMR and mass spectrometry. Meanwhile, Mito-NIR-SH could quantitatively detect H2S at concentrations ranging from 0 to 30 μM with a detection limit as low as 89.3 nM, showing good chemical stability, fast “turn-on” response, selectively mitochondrial location, as well as high sensitivity and selectivity toward H2S. Based on this, it was successfully applied to imaging exogenous and endogenous H2S in living HeLa cells via confocal fluorescence microscopy.
关键词： High sensitivity and selectivity,Near-infrared fluorescent probe,Hydrogen sulfide,Mitochondria-targeting,Bioimaging
更新于2025-09-23 15:22:29
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An ESIPT-based fluorescent probe for Hg2+ in aqueous solution and its application in live-cell imaging
摘要： A new Excited-State Intramolecular Proton Transfer (ESIPT) based fluorescent probe for the detection of Hg2+ has been rationally designed and developed. Based on the specific reactivity of mercury-promoted hydrolysis, the probe exhibits high selectivity and sensitivity for mercury ions in almost pure aqueous solution (containing only 1% DMSO) with a low detection limit of 1.9 ppb. Furthermore, the probe was also successfully used for fluorescence imaging of Hg2+ in live cells.
关键词： Fluorescent probe,ESIPT-based,Live-cell imaging,Mercury ions,3-Hydroxyphthalimide
更新于2025-09-23 15:22:29
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A novel colorimetric and ratiometric fluorescent probe for cysteine based on conjugate addition-cyclization-elimination strategy with a large Stokes shift and bioimaging in living cells
摘要： Based on conjugate addition-cyclization reaction of Cys with acrylate and subsequent 1,6-elimination of p-hydroxybenzyl moiety, a novel colorimetric and ratiometric fluorescent probe 1 was designed and synthesized. Upon addition of Cys to the solution of 1, the absorption spectra changed from 508 nm to 452 nm (?56 nm) and afforded visible color change from pink to yellow. Meanwhile, the emission spectra shifted from 644 nm to 539 nm (?105 nm) with remarkable changes in the emission ratio of F539 nm/F644 nm (R/R0 up to 760-fold), accompanying with an obvious fluorescence change from orange to green under illumination with a 365 nm UV lamp. In addition, 1 exhibited a large Stokes shift (136 nm), high sensitivity (detection limit of 46.7 nM), and excellent selectivity to Cys over Hcy and GSH. Moreover, 1 can discriminate Cys from Hcy and GSH by fluorescence spectra, even obvious visible and fluorescence color changes. Importantly, 1 can be used to image Cys in living cells by dual emission channels.
关键词： Fluorescent probe,Cysteine,Ratiometric,Bioimaging,Colorimetric
更新于2025-09-23 15:22:29
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A Novel Technique to Release Sticking Haptic of a Single-Piece Hydrophobic Acrylic IOL using Irrigation-Aspiration Probe
摘要： Purpose: To describe a novel technique to release sticking haptic of a single-piece hydrophobic acrylic intraocular lens (IOL) using irrigation-aspiration (I/A) probe. Methods: In our technique, the I/A probe is introduced into the anterior chamber on Visco mode. Using the aspiration port of the I/A probe, the sticking haptic is held at its tip and suction force is built up until occlusion is noted. Then the haptic is nudged towards the center of the IOL along its curve. After the haptic is free from optic, the suction is released. results: Several techniques have been described to release the sticking haptic such as squeezing the haptic at the site where it sticks to the IOL or using Sinskey hook for releasing the adhesion. These techniques require extra manipulation of the IOL by introduction of surgical instruments. In our technique, we used the I/A probe itself for separating the sticky haptic successfully. conclusions: This technique allows separation of sticking haptic without any extra instrumentation, thus reducing intraocular maneuvering and total surgery time.
关键词： Hydrophobic acrylic IOL,Sticking haptic,Irrigation and aspiration probe
更新于2025-09-23 15:22:29
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A rhodamine-deoxylactam based fluorescent probe for fast and selective detection of nitric oxide in living cells
摘要： Nitric oxide (NO) plays vital roles in many physiological process and is closely related to many diseases. So far, a number of fluorescent probes have been constructed for the detection of NO successfully. However, the probes still suffer from long-time reaction and limited selectivity. Herein, a fluorescent probe named dRB-OPD is synthesized and used to recognize NO. The probe contains a deoxy-rhodamine B as fluorophore and o-phenylenediamino as reaction site. dRB-OPD shows fast response to NO within 40 seconds with 170-fold fluorescence enhancement. Moreover, the probe shows high selectivity towards NO over dehydroascorbic acid (DHA), ascorbic acid (AA), and methylglyoxal (MGO). Particularly, the probe can avoid the serious interference from cysteine (Cys) found in the rhodamine lactam-based fluorescent NO probes (RB-OPD). In addition, the probe is applied for the detection of exogenous and endogenous NO in the HepG2 and RAW 264.7 cells with satisfactory results.
关键词： Cell imaging,Fluorescent probe,Nitric oxide,High selectivity,Fast response
更新于2025-09-23 15:22:29
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Hydrazine Exposé: The Next-Generation Fluorescent Probe
摘要： Hydrazine (N2H4) is one of the most important pnictogen hydride chemicals, and is utilized within a wide spectrum of industries. As a result of its extensive use, hydrazine’s monitoring methods have constantly come under fire due to its potential health risk and the subsequent environmental pollution. Fluorometric molecular sensing systems generally report with a major emphasis on the merit of fluorescence analysis. What we are proposing within this report is a next-generation fluorescent probe that allows hydrazine to become fully traceable, within multifarious environments that show fast and intuitional fluorescence transformation. A new sensing moiety, ortho-methoxy-methyl-ether (o-OMOM) incorporated electron donor (D)–acceptor (A) type naphthaldehyde provides high selectivity and sensitivity amidst its superiority within practical applications for sensing hydrazine. The new probe overcomes most of the drawbacks of currently used fluorescent probes, and due to its successful demonstrations, such as real-time spray-based sensing, soil analysis, and two-photon tissue imaging, its potential for practical application is beyond reproach.
关键词： fluorescent probe,chemical sensor,hydrazine,hydrazone-formation,two-photon tissue imaging
更新于2025-09-23 15:22:29