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- 实验方案
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Fluorescein derived Schiff base as fluorimetric zinc (II) sensor via ‘turn on’ response and its application in live cell imaging
摘要： A novel Schiff base L composed of fluorescein hydrazine and a phenol functionalized moiety has been designed and prepared via cost-effective condensation reaction, which is utilized for selective sensing of Zn2+ over other environmental and biological relevant metal ions in aqueous alcoholic solution under physiological pH range. The binding of Zn2+ to the receptor L is found to causes ~23 fold fluorescence enhancement of L. The 1:1 binding mode of the metal complex is established by combined UV–Vis, fluorescence, and HRMS (high-resolution mass spectroscopy) spectroscopic methods. The binding constant (Ka) for complexation and the limit of detection (LOD) of Zn2+ is calculated to be 2.86×104 M-1 and 1.59 μM, respectively. Further photophysical investigations including steady-state, time-resolved fluorescence analysis and spectral investigations including NMR (nuclear magnetic resonance), IR (infrared spectroscopy) suggest introduction of CHEF (chelation enhance fluorescence) with the suppression of C=N isomerization and PET (photo-induced electron transfer) mechanism for the strong fluorescent response towards Zn2+. Finally, the sensor L is successfully employed to monitor a real-time detection of Zn2+ by means of TLC (thin layer chromatography) based paper strip. The L is used in the cell imaging study using African green monkey kidney cells (Vero cells) for the determination of exogenous Zn2+ by Immunofluorescence Assay (IFA) process.
关键词： Schiff base,molecular logic gate,cell imaging,Zn sensor,PL and TCSPC,UV-Vis
更新于2025-09-23 15:23:52
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Ultrasensitive LPFG corrosion sensor with Fe-C coating electroplated on a Gr/AgNW film
摘要： This paper presents the first report on an ultrasensitive Fe-C coated long period fiber gratings (LPFG) corrosion sensor with graphene (Gr) and silver nanowire (AgNW) composite as a conductive film for Fe-C electroplating. The Gr/AgNW composite was grown on copper foil, wet transferred and adhered to the curve surface of the fiber optic sensor under atmospheric pressure and heating conditions. For comparison, another Fe-C coated LPFG sensor was prepared with silver nano ink as a conductive film. Both sensors were tested for 72 h in 3.5 wt.% NaCl solution with simultaneous measurements of transmission spectrum and electrochemical impedance spectroscopy. Due to its high optical transparency, the Gr/AgNW composite increased the wavelength sensitivity and service life of a Fe-C coated LPFG sensor by over 90% and 110%, respectively. The effective depth of influence to the evanescent field surrounding the LPFG sensor was 23.6 μm with the silver film and greater than 30 μm with the Gr/AgNW film.
关键词： Long period fiber gratings,Silver nanowire,Corrosion sensor,Fe-C coating,Graphene
更新于2025-09-23 15:23:52
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Spectral discrimination of planktonic cyanobacteria and microalgae based on deep UV fluorescence
摘要： The deep ultraviolet fluorescence characteristics of several cyanobacteria and microalgae are analyzed and exploited for their discrimination in liquid samples. The proposed approach is based on relative fluorescence peak amplitude of natural pigments in cyanobacteria or other planktonic species commonly present in water bodies. The experimental results demonstrate a clear discrimination between the various species of cyanobacteria and other planktonic species. This approach can be simply implemented in fluorescence measurement systems for real-time detection of cyanobacteria, provided that they are able to operate in deep ultraviolet.
关键词： Autofluorescence,Portable sensor,Cyanobacteria,Fluorescence spectroscopy
更新于2025-09-23 15:23:52
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Performance enhancement of ZnO nanorod-based enzymatic glucose sensor via reduced graphene oxide deposition and UV irradiation
摘要： This paper reports the performance enhancement of a ZnO nanorod-based enzymatic glucose sensor with reduced graphene oxide (rGO) introduced between the ZnO nanorods and indium tin oxide (ITO) electrode and then stimulated under UV irradiation. The electrochemical characterization indicates that the rGO not only facilitates electron transfer through the ZnO nanorods to the ITO electrode but also inhibits the fast recombination of the photo-generated electrons and holes. The UV irradiation stimulates holes in the valence band of the ZnO nanorods, which as oxidants enhance the catalytic activity of the glucose oxidase (GOx) towards glucose. The rGO increases the sensitivity of the ZnO nanorod-based glucose sensor by 1.6 times and decreases the detection limit by 2.3 times. Together with the rGO, the UV irradiation further increases the sensitivity by 1.7 times and diminishes the detection limit by 2 times. Moreover, the as-prepared glucose sensors exhibit excellent selectivity to urea, uric acid, and ascorbic acid, and can reliably determine the glucose concentration in a serum sample. The results have the potential to improve the performance of other enzymatic biosensors.
关键词： Glucose sensor,ZnO nanorod,UV irradiation,Graphene,Electrochemical test
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 cathodic photovoltammetric sensor for chloramphenicol based on BiOI and graphene nanocomposites
摘要： A visible light-activated photocathode fabricated with p-type semiconductor bismuth oxyiodide (BiOI) and graphene (G) was employed to investigate the photovoltammetric behavior of chloramphenicol (CAP). The result indicated that the voltammetric reduction peak of CAP increased to a limiting current platform under photoirradiation, owing to photoelectrocatalytic reduction of CAP on the BiOI-G photocathode. As a result, the cathodic photovoltammogram became sigmoidal in shape. Furthermore, the influences of graphene content in BiOI-G composites, scan rate and light intensity on the photovoltammetric behavior of CAP on the BiOI-G photocathode were systematically investigated. Based on such a BiOI-G electrode, a cathodic photovoltammetric sensor for CAP was proposed, which exhibited a current response linearly proportional to CAP concentration in the range of 0.5 to 50 μmol L-1, with a detection limit (3S/N) of 0.14 μmol L-1. Moreover, the photovoltammetric sensor displayed good reproducibility and high stability. The applicability of the proposed sensor was demonstrated by determining CAP in eye drop and environmental water samples.
关键词： Photovoltammetry,Photoelectrochemical sensor,Chloramphenicol,BiOI,Graphene
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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[Micro/Nano Technologies] Micro Electro Mechanical Systems Volume 2 || Micro Thermal Flow Sensor
摘要： Measurement of ?uid mechanics is very important in various ?elds, and ?ow sensors have been widely applied to execute accurate and ef?cient measurements. Compared with other sensing principle, thermal ?ow sensors are based on convective heat transfer and take merits of simple structure and easy use and thus offer a practical solution for various ?uidics applications. In this chapter, we describe mainly hot-?lm anemometer fabricated on polyimide substrate. Hot-?lm or hot-wire anemometer utilizes a thermal element that serves as both a joule heater and a temperature sensor. We introduce the principle of thermal ?ow sensing, design and fabrication of the micro hot-?lm ?ow sensor, the measurement methodology, and application cases by using the micro hot-?lm ?ow sensors.
关键词： Flow sensor,Temperature compensation,Micro anemometer,Hot ?lm,Measurement principle
更新于2025-09-23 15:23:52
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Gas sensing characteristics of the FET-type gas sensor having inkjet-printed WS2 sensing layer
摘要： This paper investigates the gas sensing characteristics of the MOSFET-type sensor having an inkjet-printed WS2 sensing layer. The drain current of the gas sensor increases when NO2 gas is injected into the test chamber since NO2 gas is an oxidizing gas that extracts electrons from the sensing layer. On the contrary, the drain current decreases when H2S gas is injected into the test chamber since H2S gas is a reducing gas that donates electrons to the sensing layer. In both cases, the change of the drain current increases as the gas concentration increases. However, for other gases (NH3 and CO2), the gas sensor has a small change of the drain current. The responses of the gas sensor to 10 ppm NO2, H2S, NH3, and CO2 gases are 15.20%, 7.18%, 1.66%, and 3.02%, respectively. Therefore, the WS2 sensor has a high selectivity for NO2 gas among the four target gases.
关键词： MOSFET,Gas sensor,Inkjet printing,WS2
更新于2025-09-23 15:23:52
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UV Illumination-Enhanced Molecular Ammonia Detection Based On a Ternary-Reduced Graphene Oxide–Titanium Dioxide–Au Composite Film at Room Temperature
摘要： In this work, we report on UV illumination enhanced room-temperature trace NH3 detection based on ternary composites of reduced graphene oxide nanosheets (rGO), titanium dioxide nanoparticles (TiO2) and Au nanoparticles as the sensing layer, which is firstly reported by far. The effect of UV state as well as componential combination and content on the sensing behavior disclosed that, rGO nanosheets served as not only a template to attach TiO2 and Au, but an effective electron collector and transporter; TiO2 nanoparticles acted as a dual UV and NH3 sensitive material; Au nanoparticles could increase the sorption sites and promote charge separation of photoinduced electron-hole pairs. The as-prepared rGO/TiO2/Au sensors were endowed with a sensing response of 8.9% toward 2 ppm NH3, a sensitivity of 1.43×10-2/ppm within the investigated range, nice selectivity, robust operation repeatability and stability, which was fairly competitive in comparison with previous work. Meanwhile, the experimental results provided clear evidence of inspiring UV-enhanced gas detection catering for the future demand of low power-consumption and high sensitivity.
关键词： Room temperature.,Gas sensor,Reduce graphene oxide,Ammonia,Au nanoparticle,Titanium dioxide,UV illumination
更新于2025-09-23 15:23:52