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Multicharged Phthalocyanines as Selective Ligands for G-Quadruplex DNA Structures
摘要： The stabilization of G-Quadruplex DNA structures by ligands is a promising strategy for telomerase inhibition in cancer therapy since this enzyme is responsible for the unlimited proliferation of cancer cells. To assess the potential of a compound as a telomerase inhibitor, selectivity for quadruplex over duplex DNA is a fundamental attribute, as the drug must be able to recognize quadruplex DNA in the presence of a large amount of duplex DNA, in the cellular nucleus. By using different spectroscopic techniques, such as ultraviolet-visible, fluorescence and circular dichroism, this work evaluates the potential of a series of multicharged phthalocyanines, bearing four or eight positive charges, as G-Quadruplex stabilizing ligands. This work led us to conclude that the existence of a balance between the number and position of the positive charges in the phthalocyanine structure is a fundamental attribute for its selectivity for G-Quadruplex structures over duplex DNA structures. Two of the studied phthalocyanines, one with four peripheral positive charges (ZnPc1) and the other with less exposed eight positive charges (ZnPc4) showed high selectivity and affinity for G-Quadruplex over duplex DNA structures and were able to accumulate in the nucleus of UM-UC-3 bladder cancer cells.
关键词： telomerase inhibition,selectivity,salmon sperm DNA,UV-Vis,circular dichroism,hyperchromism,G-Quadruplexes,G4-FID,multicharged phthalocyanines
更新于2025-11-21 11:08:12
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Hierarchical Au-Loaded WO3 Hollow Microspheres with High Sensitive and Selective Properties to Toluene and Xylene
摘要： Functionalization of metal-oxide semiconductors by noble metal nanoparticles is one of the most efficient methods for enhancing the gas-sensing property of semiconducting sensors. Herein, we synthesized a series of Au-loaded hierarchical WO3 hollow microspheres (Au-WO3) via a facile modified solvothermal method combining with wet impregnation method. The structure, elemental composition and morphology of the synthesized materials were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results show that the materials are uniform and independent WO3 hollow microspheres, and Au nanoparticles are well distributed on the surface of WO3. The gas sensing properties of Au-WO3 materials were investigated and the results suggest that Au loading could greatly improve gas sensing performance of WO3 to aromatic compounds, especially toluene and xylene. Among the samples with different Au loading content, the one with 1.5 wt% Au (G3) exhibits the highest responses toward toluene and xylene at 340 °C. Moreover, the G3 sensor presents good responses, short response/recovery time, excellent selectivity, good reproducibility and long-term stability to toluene and xylene. Excellent gas sensing properties of Au-WO3 material make it a good candidate for detecting toluene and xylene.
关键词： toluene,Au-WO3,selectivity,xylene
更新于2025-11-14 17:03:37
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Determination of Selectivity Coefficients of Sodium and Potassium Ion-Selective Electrode Using Porous Silicon N-Type (100) Based Extended Gate Field Effect Transistor
摘要： Determination of Selectivity Coefficients of Sodium and Potassium Ion-Selective Electrode Using Porous Silicon N-Type (100) Based Extended Gate Field Effect Transistor
关键词： Sodium,Selectivity Coefficients,Porous Silicon,Extended Gate Field Effect Transistor,Ion-Selective Electrode,Potassium
更新于2025-09-23 15:23:52
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Co-designed defected ground structure filter with UWB slot antenna
摘要： In this study, one kind of novel co-designed defected ground structure (DGS) filter with slot antenna is proposed to realize bandpass reflection coefficient and gain performance. This antenna consists of two parts: 1) a 50 Ω feeding line and 2) a modified stepped slot with additional narrow slot and defected ground structure. The extra narrow slot, which can effectively prolong the current path of low frequency and generate reflection zero, is introduced to improve the lower band-edge selectivity. DGS is used to improve the upper band-edge selectivity, which can produce transmission zeros in certain frequencies and provides excellent stopband characteristics. In addition, the modified stepped slot with DGS can produce additional resonance frequency, which is helpful to improve the in-band impedance characteristics and radiation efficiency of the antenna. Measured results show that not only the band-edge selectivity of the antenna is improved, but also the in-band impedance matching and radiation efficiency are improved. The experimental results show that the proposed design could be a good candidate for UWB applications.
关键词： UWB antenna,defected ground structures (DGS),band-edge selectivity
更新于2025-09-23 15:23:52
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Enhanced Selectivity for Oriented Catalyzing Tetracycline by the Functional Inorganic Imprinted ZnFe <sub/>2</sub> O <sub/>4</sub> @Ag <sub/>3</sub> PO <sub/>4</sub> /SiO <sub/>2</sub> Photocatalyst with Excellent Stability
摘要： A novel functional inorganic imprinted ZnFe2O4@Ag3PO4/SiO2 photocatalyst was synthesized by a facile sol-gel method combined with the surface imprinting technique, which possessed excellent stability. By optimizing the amount of materials to determine the preferable addition amounts of tetraethoxysilane (TEOS) and tetracycline are 0.06 mL and 0.06 g, respectively. This as-prepared functional inorganic imprinted ZnFe2O4@Ag3PO4/SiO2 photocatalyst was proved to not only exhibit high photocatalytic activity (the photodegradation rate was 61.52% under the simulated sunlight irradiation of 60 min), but also possess a strong oriented ability to selectively recognize and photocatalyze tetracycline (the coe?cient of selectivity (kselectivity) was 5.14 for ciprofloxacin and 3.63 for gatifloxacin). Moreover, the functional inorganic imprinted ZnFe2O4@Ag3PO4/SiO2 photocatalyst prepared with SiO2 as the inorganic imprinted layer have good stability and can be recycled many times. This work not only puts forward a novel design idea of functional semiconductor materials but also is expected to be widely applied to the oriented catalysis for a target substance according to the practical requirement.
关键词： selectivity,stability,ZnFe2O4@Ag3PO4/SiO2,Inorganic imprinted photocatalyst,tetracycline oriented catalysis
更新于2025-09-23 15:23:52
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ZnO-enhanced In2O3-based sensors for n-butanol gas
摘要： A series of high-response and fast-response/recovery n-butanol gas sensors was fabricated by adding ZnO to In2O3 in varying molar ratios to form ZnO-In2O3 nanocomposites via a facile co-precipitation hydrothermal method. Morphological characterizations revealed that the shape of pure In2O3 was changed from irregular cubes into irregular nanoparticles, 30-50 nm in size, with the addition of ZnO. Compared with the pure In2O3 gas sensor, the ZnO-In2O3 gas sensor exhibits superior n-butanol sensing performance. With the introduction of ZnO, the response of the sensor to n-butanol was improved from 17 to 99.5 at 180 °C for a [Zn]:[In] molar ratio of 1:1. In addition, the ZnO-In2O3 gas sensors show a reduced optimal working temperature, excellent selectivity to n-butanol, and good repeatability. The response of the ZnO-enhanced In2O3-based sensors showed a strong linear relationship with the n-butanol gas concentration, allowing for the quantitative detection of n-butanol gas.
关键词： ZnO-In2O3,n-Butanol,Gas-sensing property,Selectivity
更新于2025-09-23 15:23:52
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Near-Infrared fluorescence chemosensor based on isothiocyanate-aza-BODIPY for cyanide detection in ppb level: Applications in buffer media and living cell imaging
摘要： A near-infrared chemodosimeter based on an aza-BODIPY dye was designed and synthesized. The sensor contains isothiocyanate groups for cyanide ion sensing. The sensing function was illustrated via the fluorescence changes in near-infrared frequencies as well as chromogenic change which could be easily visualized with a detection limit of 19 ppb. The sensor provides high selectivity to CN? and discriminates other anions such as CH3COO?, HPO4 2?, HSO4 ?, NO3 ?, Cl?, F?, Br?, I?, ClO3 ?, CO3 2?, SO4 2?, and phenylalanine (Phe) in 50% PBS buffer/acetonitrile at physiological pH. The potential of the sensor for CN? detection in both aqueous buffer solutions and living cells imaging were demonstrated.
关键词： selectivity,cyanide,sensors,aza-BODIPY dyes,near-infrared fluorescence
更新于2025-09-23 15:23:52
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Highly selective and sensitive xylene gas sensor fabricated from NiO/NiCr2O4 p-p nanoparticles
摘要： Xylene is a harmful and hazardous volatile organic compound (VOC) indoors, thus selective and sensitive detection for subppm-level xylene is crucial, however a remained challenge. In this work, p-NiO/p-NiCr2O4 nanocomposites were successfully synthesized through a simple hydrothermal route and used as sensing materials. In the comparative gas sensing test, the sensor fabricated from NiO/NiCr2O4 (Cr/Ni=25 at%) nanocomposite exhibited the highest response (66.2-100 ppm) to xylene, which was 37.2 times higher than that of the pure NiO sensor. Moreover, the NiO/NiCr2O4 nanocomposite gas sensor showed not only superior xylene selectivity with low cross-responses to interfering gases such as ethanol (Sxylene/Sethanol =11.8) and acetone (Sxylene/Sacetone =10.2) but also ppb-level detection limit (1.2-50 ppb xylene) at 225 °C. The synergistic catalytic effect between NiO and NiCr2O4, optimized structural parameters and marked resistive variation due to the formation of nanoscale p-p heterojunctions were regarded as the main reasons for the ultrasensitive and selective xylene detection.
关键词： selectivity,xylene detection,heterojunction,gas sensor,NiO/NiCr2O4
更新于2025-09-23 15:23:52
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A New Catalyst Ti Doped CdO Thin Film for Non-Enzymatic Hydrogen Peroxide Sensor Application
摘要： A new material, Ti doped CdO (Ti: CdO) semiconductor, is firstly reported by this work for electrochemical non-enzymatic hydrogen peroxide (H2O2) sensor applications which was deposited by a simple, versatile and cost-effective chemical spray pyrolysis method on indium doped tin oxide (ITO) substrate. In the basic studies, first, the withstanding of cubic crystal phase along with worthy crystalline nature is discerned on CdO film after Ti doping, here only the preferentially orientated (200) diffraction plane shifted to (111). Subsequently, the irregular spherically shaped CdO nanoparticles (NPs) morphology changed as nearly uniform size with Ti doping is noticed with respect to thermal pyrolytic decomposition process. The existence of Ti atoms in Ti: CdO film is authentically identified and confirmed using EDX and XPS studies respectively. The absorption and emission properties of CdO and Ti: CdO films are studied and confirmed their narrow band gap nature. Importantly, the Ti: CdO film shows pronounced electrocatalytic activity for the reduction of hydrogen peroxide (H2O2) as compared to pure CdO. Hence, the non-enzymatic electrochemical sensing of Ti: CdO electrode shows a lower detection limit 0.4 μM with the linear range of 10-190 μM which displayed a fast amperometric response for 5 s with sensitivity of 0.27 μA μM-1 cm-2 toward H2O2 detection. This result will boost exploring a new opportunity for the deposition of other metal oxides and semiconductors by using a simple chemical spray pyrolysis method for detection of non-enzymatic H2O2 sensor applications.
关键词： H2O2 sensor,and selectivity,Chemical spray pyrolysis,Ti: CdO thin film
更新于2025-09-23 15:23:52
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Boron doped carbon dots as a multifunctional fluorescent probe for sorbate and vitamin B12
摘要： Boron doped carbon dots (B-CD) were synthesized by a one-step hydrothermal method using phenylboronic acid as the starting material. They have an average size of about 3.3 nm, with excitation/emission wavelength of 247/323 nm and a quantum yield of 12%. The B-CD is shown to be viable fluorescent probe for sorbate (PS) and vitamin B12 (VB12). The fluorescence (FL) of the B-CD is quenched in the presence of PS or VB12 mainly coming from inner filter effect (IFE), but F?rster resonance energy transfer (FRET) from the B-CD (as a donor) to PS/VB12 (as an acceptor) cannot be excluded. The probe enables PS to be detected by fluorometry with a linear response in the 0.20–24 μM concentration range and a 6.1 nM detection limit (at 3σ/slope). For VB12, the data are 0.20–30 μM and 8.0 nM.
关键词： Fluorescent probe,Sorbic acid,Fluorescence quenching ratios,Intra-day precision,Selectivity,Inter-day precision,Quenching mechanism,Real sample analysis
更新于2025-09-23 15:23:52