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A novel dicationic Quinoline-Carzole fluorescent probe：Preparation and labeling of <i>Microthrix parvicella</i>
摘要： A novel dicationic Quinoline-Carbazole fluorescent probe with hydrophobic long-chain alkane was designed and synthesized based on the property of Microthrix parvicella (M. parvicella) in situ utilizing long-chain fatty acids (LCFA) in the activated sludge system. 1H NMR spectrum, ultraviolet-visible (UV-Vis) absorption spectra, and fluorescent spectra analysis demonstrated that the probe was successfully obtained. The probe had a large stokes-shift ranging from 102 to 144nm in different solvents, which were benefit for the fluorescent labeling properties. The labeling experiment indicated that the prepared probe could absorb onto the surface of M. parvicella through hydrophobic bond. Much stronger yellow fluorescence of M. parvicella was observed at the concentration of 1.0×10-5mol/L when compared with the zooglea, which makes it easy to distinguish M. parvicella from the zooglea. In addition, the photostability of the probe was also investigated, and the result showed that the probe was quite stable in a long period of time. All the results indicated that the prepared probe was suitable for the labeling of M. parvicella.
关键词： Dicationic Quinoline-Carbazole,fluorescent probe,Characterization,labeling,Microthrix parvicella
更新于2025-09-23 15:22:29
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Template-driven dense packing of pentagonal molecules in monolayer films
摘要： The integration of molecules with irregular shape into a long-range, dense and periodic lattice represents a unique challenge for the fabrication of engineered molecular scale architectures. The tiling of pentagonal molecules on a 2D plane can be used as a proof-of-principle investigation to overcome this problem since basic geometry dictates that a two-dimensional (2D) surface cannot be filled with a periodic arrangement of pentagons, a fundamental limitation that suggests that pentagonal molecules may not be suitable as building blocks for dense films. However, here we show that the 2D covalent organic framework (COF) known as COF-1 can direct the growth of pentagonal guest molecules as dense crystalline films at the solution/solid interface. We find that the pentagonal molecule corannulene adsorbs at two different sites on the COF-1 lattice, and that multiple molecules can adsorb into well-defined clusters patterned by the COF. Two types of these dense periodic packing motifs lead to a five-fold symmetry reduction compatible with translational symmetry, one of which gives an unprecedented high molecular density of 2.12 molecules/nm2.
关键词： host-guest system,fivefold symmetry,scanning probe microscopy,pentagonal molecules
更新于2025-09-23 15:21:21
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A self-assembly/disassembly two-photo ratiometric fluorogenic probe for bacteria imaging
摘要： A fluorogenic probe for bacteria imaging was reported. The binding with anionic bacterial surfaces disassembled the self-assembly probe to turn-on the fluorescence and shift pyrene monomer/excimer ratiometric signals.
关键词： Self-assembly,Pyrene,Bacteria,Fluorogenic probe,Imidazolium
更新于2025-09-23 15:21:21
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A Phosphonate Substituted Ruthenium(II) Bipyridyl Derivative as Photoelectrochemical Probe for Sensitive and Selective Detection of Mercury(II) in Biofluids
摘要： A ruthenium(II) bipyridyl derivative photoelectrochemical probe, Ru-1, is synthesized and coupled with TiO2 nanoparticles (Ru-1/TiO2) for the specific recognition and highly sensitive PEC detection of Hg2+ in a series of biofluids. The probe is designed with a chromophore, a thiocyanate recognition unit, a π-conjugated photoelectron transfer pathway, and a phosphonate anchor. TiO2 nanoparticles with strong affinity to phosphonate and suitable conduction band energy are used as intermediate layers to increase the Ru-1 adsorption amount and amplify the photocurrent response. Under irradiation, the Ru-1/TiO2/FTO with strong visible light harvesting capacity, aqueous stability and efficient photoelectron transfer, shows a high and stable photocurrent response. In the presence of Hg2+, however, the specific Hg2+ and NCS coordination changes the photophysical properties of Ru-1, imposing the probe with a wider band gap, a weaker absorbance, and a poorer photoelectron and hole separation efficiency, thus resulting in a significant photocurrent decrease. Based on the Hg2+ induced photocurrent change, the Ru-1/TiO2/FTO shows good selectivity and high sensitivity towards the PEC detection of Hg2+, with wide linear ranges from 10-12 to 10-7 and 10-7 to 10-3 g/mL, and a low limit of detection of 0.63 pg/mL. The PEC probe is recyclable and accurate for selective detection of Hg2+ in urine, serum and cell extracts. The whole analysis can be completed within 15 minutes. These good analytical performances indicate the PEC method might have great potential for the onsite detection of small molecules in bio-systems.
关键词： Hg2+ detection,photoelectrochemical probe,TiO2 nanoparticles,ruthenium(II) bipyridyl derivative,biofluids
更新于2025-09-23 15:21:21
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Electrode-free anodic oxidation nanolithography of low-dimensional materials
摘要： Scanning probe lithography based on local anodic oxidation (LAO) provides a robust and general nanolithography tool for a wide range of applications. Its practical use, however, has been strongly hampered due to the requirement of a pre-fabricated micro-electrode to conduct the driving electrical current. Here we report a novel electrode-free LAO technique, which enables in-situ patterning of as-prepared low-dimensional materials and heterostructures with great flexibility and high precision. Unlike conventional LAO driven by a DC current, the electrode-free LAO is driven by a high-frequency (>10 kHz) AC current applied through capacitive coupling, which eliminates the need of a contacting electrode and can be used even for tailoring insulating materials. Using this technique, we demonstrated flexible nanolithography of graphene, hexagonal boron nitride (hBN), and carbon nanotubes (CNTs) on insulating substrates with ~10-nanometer precision. In addition, the electrode-free LAO exhibits high etching quality without oxide residues left. Such an in-situ and electrode-free nanolithography with high etching quality opens up new opportunities for fabricating ultraclean nanoscale devices and heterostructures with great flexibility.
关键词： electrode-free local anodic oxidation,graphene,high-frequency AC voltage,low-dimensional materials,Scanning probe lithography
更新于2025-09-23 15:21:21
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High Performance Fluorescent Turn-On Probe for Amitriptyline Based on Hybrid Nanoassembly of Organic–Inorganic Nanoparticles
摘要： Fluorescence methods have gained enormous attention due to their ease in use, simplicity, selectivity and sensitivity. Fluorescent chemosensors respond instantly by converting molecular recognition to fluorescent signals. The consumption of pharmaceutical products by living beings is on great increase. The disposal of such compounds in the environment is a matter of great concern as these compounds enter aquatic environment and are showing accumulation in tissues of aquatic organisms. In the present study, we have utilized naphthalimide based receptors to fabricate organic nanoparticles. These ONPs were used for the development of hybrid nanoassemblies and the developed nanoassemblies were characterized with the help of TEM and DLS studies. The photophysical studies were performed and the hybrid assembly developed using receptor 2 demonstrated a turn-on fluorescence emission behaviour on binding with Amitriptyline. The present sensing system acted as promising candidate for determination of Amitriptyline among other contending drug molecules. The established system can recognize amitriptyline up to a detection limit of 48 nM in aqueous medium. Electrochemical recognition studies show binding of hybrid nanoassembly of receptor 2 with Amitriptyline with limit of detection of 21 nM.
关键词： Turn-On Probe,Fluorescent Organic Nanoparticles,Amitriptyline,Nanomolar Detection,Hybrid Nanoassembly
更新于2025-09-23 15:21:21
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Enhanced Raman Detection System based on a Hollow-core Fiber Probe design
摘要： This paper focus on an enhanced Raman-based detection probe and its performance evaluated. The probe employs a hollow-core fiber design to allow liquid micro-sample to be analyzed. The hollow-core fiber is used both to transmit the light signal used to excite the sample and to collect the Raman scattering signal received from the micro-sample under analysis. In order to maximize the performance of the system, various parameters have been studied experimentally, including the diameter and the height of the liquid sample in the probe. The aim has been optimizing both as a means to enhance the Raman scattering signal received from the liquid sample. As a result, a Raman-based detection probe using a reflector approach was developed and evaluated. This design enabling a greater area for interaction with the sample to be formed and to concentrate the excitation light into it. This then increases the efficiency of the light-liquid interaction and improves the collection efficiently of the forward Raman scattering light signal. With the use of this design, the detected Raman scattering signal was increased by a factor of 103~104 over what otherwise would be achieved. A key feature is that with the use of a hollow-core fiber to collect the liquid sample, only a very small volume is needed, making this well suited to practical applications where limited amounts of material are available e.g. biofluids or high value liquids. The system designed and evaluated thus provides the basis of an effective all-fiber Raman-based detection system, capable of being incorporated into portable analysis equipment for rapid detection and in-the-field use.
关键词： small liquid sample measuring method,enhanced structure,Raman detection probe,Hollow-core fiber (HF)
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Suppression of electron emission from cathode in photoemission-assisted Ar plasma
摘要： In order to improve the efficiency of the surface flattening process using photoemission-assisted plasma ion source, current-bias voltage characteristic and Ar+ ions/Ar atoms ratio in the plasma was investigated. The glow discharge starting voltage decreases by UV irradiation and a great number of Ar+ ions were irradiated to the substrate. On the other hand in PA Townsend discharge, the number of Ar+ ions reached at the substrate is smaller than that in glow discharge due to space charges near the cathode substrate.
关键词： space charge effect,Langmuir probe,photoemission-assisted plasma
更新于2025-09-23 15:21:21
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Near-field spatial frequency filtering model for surface plasmon self-interference virtual probe
摘要： The azimuthal angle relation for obliquely excited standing-wave surface plasmon is analytically studied in detail and thereby a near-field spatial frequency filtering model is proposed, in which the azimuthal angle relation and criterion similar to Heisenberg uncertainty principle are combined to describe the spatial resolving power of surface plasmon self-interference virtual probe imaging system. It is revealed that the incidence coupling possesses spatial anisotropy due to polarization modulation, and the mechanism for spatial resolution degradation is the compression of spatial frequency bandwidth in the near-field domain.
关键词： spatial frequency filter,virtual probe,surface plasmon self-interference
更新于2025-09-23 15:21:21
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Enhancement of attosecond pulse in water window region by using pump-probe approach
摘要： An effective scheme to enhance the harmonic yield and the attosecond (as) pulse signal from H+2 has been proposed by using the pump-probe laser field. It is found that with the help of the multi-cycle pump pulse, H+2 can be steered into the resonance ionization regions, where the ionization probability can be remarkably enhanced. Thus, the harmonic yield can be remarkably enhanced when a sequential mid-infrared probe pulse is added. Further, by modulating the phase of the probe pulse and by adding a controlling pulse, the harmonic cutoff can be extended up to the water window region. Finally, by the Fourier transformation of the selected harmonics on the harmonic supercontinuum, the water window attosecond pulses as short as 25 as can be obtained.
关键词： High-order harmonic generation,pump-probe pulse,charge resonance enhanced ionization,single attosecond pulse,harmonic enhancement
更新于2025-09-23 15:21:21