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A turn-on reactive fluorescent probe for Hg2+ in 100% aqueous solution
摘要： It is an effective and precise strategy to design the fluorescence probe for Hg2+ based on a new specific reaction. A novel turn-on fluorescent probe, 4-{2-[4-(2-Mercapto-benzoyloxy)-phenyl]-vinyl}-1-methyl-pyridinium[e]iodide (MBPVP) for Hg2+ was developed. The mechanism was based on Hg2+-mediated ester hydrolysis to release the fluorophore, 4-[2-(4-Hydroxy-phenyl)-vinyl]-1-methyl-pyridinium[e]iodide, which showed outstanding intramolecular charge transfer (ICT) and the yellow-green fluorescence were observed. The turn-on probe showed rapid response time, outstanding selectivity and sensitivity for Hg2+ over other metal ions in 100% PBS buffer (pH = 7.4). The linear range was 2-16 μM and the detection limit was 6.5 nM. Furthermore, MBPVP was used to determine Hg2+ in real samples and in the solid state.
关键词： Hg2+,ester hydrolysis,MBPVP,100% aqueous solution,fluorescent probe
更新于2025-09-23 15:23:52
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Black phosphorus nanosheets based sensitive protease detection and inhibitor screening
摘要： Proteases, as one of the most significant kind of digestive enzymes, are closely related to a variety of physiological processes and diseases. Herein, a black phosphorus nanosheets (BPs) based sensitive fluorometric method for protease detection and inhibitor screening is proposed. The aqueous solution of perylene probe (probe 1) displays a strong fluorescence. BPs, as novel discovered two-dimensional (2D) materials, can adsorb probe 1 through electrostatic interactions, which causes fluorescence quenching of probe 1. Histone can control the interactions between the perylene probe and BPs, which can be further regulated by the introduction of a protease. Thus, the protease activity can be monitored by detecting the fluorescence intensity changes of probe 1. The method is label free, sensitive and selective. As low as 1 ng/mL trypsin can be easily detected.
关键词： trypsin,inhibitor,protease,black phosphorus nanosheets,fluorescence,perylene probe
更新于2025-09-23 15:23:52
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Activity-based Near-Infrared Fluorogenic Probe Enables In Vitro and In Vivo Profiling of Neutrophil Elastase
摘要： Neutrophil elastase (NE), a typical hematopoietic serine protease, has significant roles in inflammatory and immune responses, and thus highly associated with various diseases such as acute lung injury (ALI) and lung cancer. Rapid and accurate measurement of NE activity in biological systems is particularly important for understanding the role of NE in inflammatory diseases, as well as the clinic diagnosis. However, the specific detection and non-invasive imaging of NE in vivo remains a challenge. To address this issue, a small-molecule substrate-based near-infrared fluorogenic probe (NEP) for NE was constructed via incorporating pentafluoroethyl as the recognition group with a hemicyanine dye-based fluorophore. This initially quenched probe possesses over than 25-fold red fluorescence enhancement upon the catalysis of human NE and the detection limit is about 29.6 ng/mL. In addition, the high specificity and the long emission wavelength (λemmax = 700 nm) of NEP allowed the direct monitoring of NE-trafficking, exogenous NE up taking and endogenous NE up-regulation at the cellular level. Moreover, the successfully spatiotemporal imaging of NE in ALI model mice also made it a promising new tool in clinical diagnosis for ALI and other lung diseases.
关键词： intracellular trafficking,Neutrophil elastase,acute lung injury.,fluorogenic probe
更新于2025-09-23 15:23:52
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Measurement of Forces between Supported Cationic Bilayers by Colloid Probe Atomic Force Microscopy: Electrolyte Concentration and Composition
摘要： The interactions between supported cationic surfactant bilayers were measured by colloidal probe atomic force spectroscopy, and the effect of different halide salts was investigated. Di(alkylisopropylester)dimethylammonium methylsulfate (DIPEDMAMS) bilayers were fabricated by the vesicle fusion technique on muscovite mica. The interactions between the bilayers were measured in increasing concentrations of NaCl, NaBr, NaI, and CaCl2. In NaCl, the bilayer interactions were repulsive at all concentrations investigated, and the Debye length and surface potential were observed to decrease with increasing concentration. The interactions were found to follow the electrical double layer (EDL) component of DLVO theory well. However, van der Waals forces were not detected; instead, a strong hydration repulsion was observed at short separations. CaCl2 had a similar effect on the interactions as NaCl. NaBr and NaI were observed to be more efficient at decreasing surface potential than the chloride salts, with the efficacy increasing with the ionic radius.
关键词： supported bilayers,DLVO theory,Debye length,surface potential,halide salts,colloidal probe atomic force spectroscopy
更新于2025-09-23 15:23:52
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Contactless Optical Characterization of Carrier Dynamics in Free-Standing InAs-InAlAs Core-Shell Nanowires on Silicon
摘要： Contactless time-resolved pump-probe and external quantum efficiency measurements were performed on epitaxially grown free-standing wurtzite indium arsenide/indium aluminum arsenide (InAs-InAlAs) core-shell nanowires on Si (111) substrate from 77K to 293K. The first independent investigation of Shockley-Read-Hall, radiative and Auger recombination in InAs-based NWs is presented. Although the Shockley-Read Hall recombination coefficient was found to be at least two orders of magnitude larger than the average experimental values of other reported InAs materials, the Auger recombination coefficient was reported to be ten-fold smaller. The very low Auger and high radiative rates result in an estimated peak internal quantum efficiency of the core-shell nanowires as high as 22% at 77K, making these nanowires of potential interest for high efficiency mid-infrared emitters. A greater than two-fold enhancement in minority carrier lifetime was observed from capping nanowires with a thin InAlAs shell due to passivation of surface defects.
关键词： Auger recombination rate,radiative,Shockley-Read-Hall,Pump-probe spectroscopy,core-shell nanowires,surface/interface recombination velocity,minority carrier lifetime
更新于2025-09-23 15:23:52
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Rational Design of Near-Infrared AIE-Active Probes: In Situ Mapping of Amyloid-β Plaques with Ultra-Sensitivity and High-Fidelity
摘要： High-fidelity mapping of amyloid-β (Aβ) plaques is critical for the early detection of Alzheimer’s disease. However, in vivo probing of Aβ plaques by commercially available Thioflavin derivatives (ThT or ThS) has proven to be extremely limited, as evident by the restriction of enrichment quenching effect, low signal-to-noise (S/N) ratio and poor blood-brain barrier (BBB) penetrability. Herein, we demonstrate a rational design strategy of near-infrared (NIR) aggregation-induced emission (AIE)-active probes for Aβ plaques, through introducing lipophilic π-conjugated thiophene-bridge for extending to NIR wavelength with enhancement of BBB penetrability, and tuning the substituted position of sulfonate group for guaranteeing specific hydrophilicity to keep fluorescence-off state before binding to Aβ deposition. Probe QM-FN-SO3 has well settled the AIE dilemma between lipophilic requirement for longer emission and aggregation behavior from water to protein fibrillogenesis, thus making a breakthrough in high-fidelity feedback on in vivo detection of Aβ plaques with remarkable binding affinity, and serving as an efficient alternative to the commercial probe ThT or ThS.
关键词： Fluorescent probe,In vivo imaging,Aggregation-induced emission,Amyloid-β plaques,Near-infrared
更新于2025-09-23 15:23:52
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A new lysosome-targetable fluorescent probe with a large Stokes shift for detection of endogenous hydrogen polysulfides in living cells
摘要： Hydrogen polysulfides (H2Sn, n>1) influence a variety of important biological functions and activities associated with hydrogen sulfide (H2S). The development of probes for rapid, selective, and sensitive detection of H2Sn still remains a great challenge. Lysosome plays crucial roles in various physiological processes among living cells, which arouse high interest in detecting endogenous lysosome-targetable H2Sn. To the best of our knowledge, there is no lysosome-targetable probe for H2Sn has been reported. In this work, a new lysosome-targetable probe NIPY-NF, based on the scaffold of imidazo[1,5-α]pyridine, with a large Stokes shift (215 nm), low detection limit (84 nM), fast response time (6 min) and low cytotoxicity was designed and synthesized. Furthermore, NIPY-NF was successfully applied into the cell imaging for detection of endogenous lysosome-targetable H2Sn.
关键词： Hydrogen polysulfides,Fluorescent probe,Lysosome,Cell imaging,Imidazo[1,5-α]pyridine
更新于2025-09-23 15:23:52
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Formation of Cobalt Impurity Microinclusions in Silicon Single Crystals
摘要： The structure and chemical composition of cobalt impurity microinclusions in silicon have been studied by electron probe microanalysis using n- and p-type Si?Co? samples prepared by diffusion doping and cooled at different rates after diffusion annealing. The cooling rate after diffusion annealing has been shown to have a significant effect on the structural parameters of the samples and the size of the forming impurity microinclusions. The size and shape of the impurity microinclusions determine their distribution over the bulk of the samples.
关键词： cobalt microinclusions,cobalt silicide,cooling rate,electron probe microanalysis
更新于2025-09-23 15:23:52
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Ultrafast electron-lattice thermalization in copper and other noble metal nanoparticles
摘要： Using time-resolved ultrafast pump-probe spectroscopy we investigated the electron-lattice energy transfer in small copper nanospheres with diameters ranging from 3.2 to 23 nm, either embedded in a glass or dispersed in a solvent. Electron-lattice scattering rate is shown to increase with size reduction, in agreement with our previous results obtained on gold and silver nanoparticles in the low excitation regime. We attribute this effect to the reduction of the screening efficiency of electron–phonon interactions close to the nanoparticle surface. To understand the discrepancy between the results on the electron-lattice scattering in different metals reported in the literature (reduction, no dependence or increase with nanoparticle size), we discuss the experimental conditions required for the accurate determination of electron-lattice energy transfer time from time-resolved investigations in the weak and strong excitation regimes and present power-dependent experiments on gold nanospheres in solution. Our findings are derived from a theoretical analysis based on the two-temperature model predictions and on a complete modeling of the nanoparticle transient extinction cross-section through the resolution of Boltzmann equation in the presence of hot electrons.
关键词： pump-probe spectroscopy,copper nanoparticles,electron-lattice interactions,two-temperature model,ultrafast electron dynamics
更新于2025-09-23 15:23:52
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Atom localization using Laguerre-Gaussian beams
摘要： Use of the Laguerre-Gaussian beams in an atom-light interaction makes the linewidth of the optical spectrum narrow. We exploit this fact for providing the ability to accomplish simultaneous ultra-high precision and spatial resolution atom localization in a double-Λ atomic system; under multi-photon resonance condition, the resolution of the localization is remarkably improved so that the atom can be localized in a region smaller than λ/100 × λ/100. Most prominently, the probability of finding the atom at a particular position is always 100%, when a photon with certain frequencies is absorbed or amplified. Such features are mainly attributed to radial dependence associated with the Laguerre-Gaussian beams in a spatially dependent atom-light interaction.
关键词： Laguerre-Gaussian beams,probe absorption,2D atom localization
更新于2025-09-23 15:23:52