ALBERT

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Yuan Chen, Xue-Rui Wei, Ru Sun, Yu-Jie Xu, Jian-Feng Ge〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Five cyanine dyes (〈strong〉1a-e〈/strong〉) with azonia unit have been prepared by the reaction of pyrido[1,2−a]pyrimidinium ions and suitable aldehydes. Before further research, their photo and thermal stabilities were determined in the first place. At least 88% absorption remained after 5 h irradiating illustrated all of these dyes had excellent photo stability. Meanwhile, the decomposition temperature of dyes was around 200 °C which demonstrated they had good thermal stability. Therefore, the good photo and thermal stability made them possible to be probes. Subsequently, the optical properties of probes toward nucleic acids had been measured. TheirOFF–ON fluorescent responses (〈strong〉1a〈/strong〉-〈strong〉d〈/strong〉) towards nucleic acids were investigated. In addition, confocal microscopy imaging of probe 〈strong〉1a〈/strong〉 in live HeLa cells indicated that probe 〈strong〉1a〈/strong〉 could image mitochondrial nucleic acid.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518319233-ga1.jpg" width="398" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): S. Pimenta, S. Cardoso, E.M.S. Castanheira, G. Minas〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents a CMOS optical microsystem with a 4 × 4 photodiodes array and their readout electronics, based on 16 light-to-frequency converters, and 16 high selective optical filters, for spectrophotometric measurement of diffuse reflectance and fluorescence signals, applied to the detection of gastrointestinal dysplasia. The photodiodes array is based on n+/p-epilayer junction silicon photodiodes. Their readout electronics outputs a digital signal, with a frequency proportional to the photodiode current, featuring a sensitivity of 26 Hz/nA at 550 nm, a spectral resolution of 9 MHz and a power consumption of 1 mW. The optical filters are based on 16 thin-film narrow-band 〈em〉Fabry-Perot〈/em〉 resonators, in which dielectric mirrors are used. They feature high transmittances and low full-width-half-maximum. Experimental measurements, using phantoms representative of the main absorbing, scattering and fluorescence properties of gastrointestinal tissues, proved the viability of the CMOS optical microsystem with the optical filters to extract those signals, when comparing the obtained results with commercial equipment. The implemented apparatus is ready to be used as a portable system on a surgery room to verify the total removing of gastrointestinal cancer tissue. Moreover, the developed approach is a step forward in the implementation of a gastrointestinal dysplasia detection miniaturized tool.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Xueli Yang, Sufang Zhang, Qi yu, Liupeng Zhao, Peng Sun, Tianshuang Wang, Fangmeng Liu, Xu Yan, Yuan Gao, Xishuang Liang, Sumei Zhang, Geyu Lu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, a novel branched heterostructural composite composed of nanorods ZnO backbone and SnO〈sub〉2〈/sub〉 branches was prepared via a facile one-step hydrothermal method. The morphology, structure and component of the SnO〈sub〉2〈/sub〉/ZnO composite was characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and elemental mapping analysis. The evolution process of the SnO〈sub〉2〈/sub〉/ZnO composite was observed by SEM that the SnO〈sub〉2〈/sub〉 branches gradually grow on ZnO backbones. The composite with novel heterostructure was applied as the sensing material for the fabrication of gas sensor, and their gas sensing properties were tested for response to various gases. Compared to pure ZnO gas sensors the branched SnO〈sub〉2〈/sub〉/ZnO gas sensor exhibited enhanced gas sensing properties toward ethanol, giving a response of 18.1–100 ppm.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Qian Ma, Pin Li, Zhiqiang Gao, Sam Fong Yau Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A simple fluorescence biosensor for rapid and sensitive target microRNA (miRNA) quantification by branched rolling circle amplification (BRCA) is developed in this work. Target miRNA functions as primer to recognize and hybridize with a circle DNA template, initiating rolling circle amplification (RCA) by Phi29 DNA polymerase. The introduction of reverse primers complementary to the RCA products enables isothermal BRCA, in which a large amount of deoxynucleotide (dNTP) were consumed and same number of pyrophosphates (PPi) were produced. In this study, a simple and non-expensively synthesized terpyridine-based Zn(II) complex is utilized as fluorescent probe for selective detection of pyrophosphate (PPi) over dNTP. The PPi generated in this isothermal amplification process efficiently chelates to this terpyridine-Zn(II) complex, forming a highly fluorescent complex, terpyridine-Zn(II)-PPi, whose fluorescence intensity is closely related with the initial target miRNA concentration. The utilization of the isothermal BRCA amplification and direct monitoring of the DNA polymerization by-product, i.e. PPi, for non-label fluorescence detection of miRNA greatly simplify this sensor procedure. This sensor shows a linear response between the fluorescence intensity and the target miRNA concentration from 50 to 500 fM with a detection limit of 25 fM. This much-simplified sensor offers a sensitive and easy-to-use platform for miRNA quantification, and hence may significantly enhance the utilisation of miRNAs as biomarkers in drug discovery, clinical diagnosis and life science research.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092540051831918X-ga1.jpg" width="245" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Ganesan Muthusankar, Chellakannu Rajkumar, Shen-Ming Chen, Rajendran Karkuzhali, Gopalakrishnan Gopu, Arumugam Sangili, Nallathambi Sengottuvelan, Raman Sankar〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report a simple preparation of novel nanocomposite for the sensitive determination of riboflavin (RF) in real samples. Nitrogen-doped carbon quantum dots/SnO〈sub〉2〈/sub〉 (N-CQD/SnO〈sub〉2〈/sub〉) nanocomposite was prepared using sonochemical approach and applied as a voltammetric sensor for the sensitive determination of RF for the first time. The crystallographic phase, functional groups, surface analysis, and elemental distribution were examined using XRD, FT-IR, HR-TEM and EDS spectroscopic techniques respectively. This N-CQD/SnO〈sub〉2〈/sub〉 nanocomposite-modified electrode shows a fast and sensitive electrochemical response to RF sensing with a good sensitivity (2.496 μA μM〈sup〉−1〈/sup〉 cm〈sup〉-2〈/sup〉), wide linear range (0.05–306 μM), low detection limit (8 nM) and excellent anti-interference ability. Furthermore, the developed sensor was investigated in commercial riboflavin tablets and milk powder and obtained results are quite satisfactory.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518319221-ga1.jpg" width="329" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Aritz Ozcariz, Dafne A. Piña-Azamar, Carlos R. Zamarreño, René Dominguez, Francisco J. Arregui〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This work presents the experimental demonstration of lossy mode resonance generation by means of aluminum doped zinc oxide thin-films. The use of such material may allow to optimize the performance of LMR-based sensors, obtaining good sensitivity at lower costs than other overlays, such as those including indium. The refractometric response of the fabricated devices is explored in different spectral regions. One refractometer working in the near infrared region was fabricated, obtaining a sensitivity of 2280 nm/RIU. A second refractometer working in the visible light spectrum was also fabricated. This second device allows to observe rough refractive index variations with the naked eye as a change of the color of the light propagating through the fiber, simplifying the setup needed for its use.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Ling Yang, Hengjia Ni, Chenglong Li, Xiya Zhang, Kai Wen, Yuebin Ke, Huijuan Yang, Weimin Shi, Suxia Zhang, Jianzhong Shen, Zhanhui Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Antibody-based sensors are the most widely used for screening antibiotic residues in food samples. However, these sensors always suffer from cross-reacting antibiotics which are able to bind the employed antibodies in a manner similar to the target, thus resulting in inaccurate quantification. In this study, we developed a highly specific and sensitive chemiluminescence aptasensor for sulfamethazine (SMZ) by employing the supernormal selectivity of a new selected aptamer. Four SMZ-specific aptamers (〈em〉K〈sub〉d〈/sub〉〈/em〉 ranging from 79 to 274 nM) were selected 〈em〉in vitro〈/em〉 by MB-SELEX with an intentional counter selection to avoid the recognition other sulfonamides, which is impossible to achieve in the corresponding procedure of antibody production. The binding mechanism of aptamers for SMZ was further analyzed and clarified with molecular simulation and docking. Under optimum conditions, the chemiluminescence aptasensor based on the highest affinity aptamer named SA07 provided a limit of detection of 0.92 ng/mL with negligible cross-reactivity with the 27 tested sulfonamides. The developed aptasensor was applied to milk samples, and achieved good accuracy and precision. These results demonstrated that the integration of an aptamer and chemiluminescence in a sensor platform is a promising method for the sensitive, specific, rapid and accurate detection of antibiotic residues of interest in food samples.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518319208-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Łukasz Janicki, Jan Misiewicz, Marcin Siekacz, Henryk Turski, Joanna Moneta, Sandeep Gorantla, Czesław Skierbiszewski, Robert Kudrawiec〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Modulation spectroscopy was applied to study the N-polar GaN surface barrier height dependency on ambient gas type in GaN/GaN:Si and GaN/AlGaN/GaN heterostructures. The built-in electric field in the undoped layer of the GaN/GaN:Si structure was determined by an analysis of a Franz-Keldysh oscillation present in spectra and used to calculate the surface barrier in presence of various gases. A barrier of 0.35 eV in air and N〈sub〉2〈/sub〉+O〈sub〉2〈/sub〉 (82:18 ratio) mixture ambient was determined while in vacuum, N〈sub〉2〈/sub〉, Ar and SF〈sub〉6〈/sub〉 it amounted to 0.20 eV. No effect of humidity on the surface barrier was observed. The GaN channel built-in electric field of the GaN/AlGaN/GaN heterostructure was also determined from optical studies. It was then used as a parameter in a self-consistent solution of Schrödinger-Poisson equations in order to calculate the surface barrier for this structure in air and vacuum ambient, and the results matched those obtained for the UN + structure. This indicated that the electronic state of surface behaves in the same way irrespectively of the structure design. Calculated carrier concentration of the GaN/AlGaN/GaN heterostructure shows a significant dependency on the surface barrier indicating a possible application in gas sensing. The response time was also studied showing a fast (〈10 s) barrier increase in presence of oxygen and a much slower decrease when oxygen was removed.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Jiaoyan Qiu, Yujie Zhang, Chen Dong, Yunlong Huang, Li Sun, Huimin Ruan, Hongsen Wang, Xing Li, Aiguo Wu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Potassium ions (K〈sup〉+〈/sup〉) play an important role in biological organisms. Therefore, efficient and sensitive detection of K〈sup〉+〈/sup〉 in biological complex samples is crucial for disease diagnosis. Herein, we propose a novel sensor based on crown ether (4-aminobenzo-18-crown-6, ABC) modified Au NPs for rapid colorimetric detection of K〈sup〉+〈/sup〉. Recognition of K〈sup〉+〈/sup〉 and constitution of the aggregates are posed by a sandwich complex of 2:1 between ABC moiety and K〈sup〉+〈/sup〉. Based on the aggregation mechanism, this colorimetric detection method has superior selectivity and anti-interference ability for potassium ions (K〈sup〉+〈/sup〉) compared with other ions. There is a good linear relationship (R〈sup〉2〈/sup〉 = 0.9979) in the range of 0–200 μM K〈sup〉+〈/sup〉 concentration and this detection method can be successfully applied in the detection of K〈sup〉+〈/sup〉 in real urine samples.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518319166-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Hui-Min Wang, Chen-Chen Wang, Ai-Jun Wang, Lu Zhang, Xiliang Luo, Pei-Xin Yuan, Jiu-Ju Feng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electrochemiluminescence (ECL) has attracted significant interest because of its superior properties and potential applications in bioanalysis, and therefore many luminescent nanomaterials have been developed. Herein, well-defined Pd nanocones (Pd NCs) were facilely obtained by a one-pot hydrothermal method with poly-〈span〉l〈/span〉-lysine (PLL) as a green protecting ligand, which were mainly characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Then, the as-obtained Pd NCs were first explored as an anodic ECL emitter, where tripropylamine (TPA) worked as the coreactant to boost the ECL emission. The possible ECL mechanism of Pd NCs/TPA system was extensively explored by ECL and electrochemical techniques. Briefly, the ECL emission underwent the oxidation-reduction route, in which both Pd NCs and TPA were initially oxidized, and then the oxidized TPA lost an proton to form reducing agent (TPA〈sup〉·〈/sup〉) strongly reacted with the oxidized Pd NCs generating Pd NCs* for the emission. Furthermore, using dopamine (DA) as an ECL quencher, an ultrasensitive sensor was constructed for DA detection. The fabricated ECL sensor shows high sensitivity and selectivity, good stability, and wide linear range with the low detection limit of 0.46 pM. It offers a new avenue to exploit ECL illuminant and enriches the ECL emission theory.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518319300-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Matteo Tonezzer, Jae-Hun Kim, Jae-Hyoung Lee, Salvatore Iannotta, Sang Sub Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The detection of volatile compounds is important for a broad variety of applications. Metal oxide gas nanosensors are tiny, inexpensive devices that can be integrated into any application, but they lack selectivity. On the other hand, electronic noses consisting of sensors arrays comprised of different active materials are complex as well as expensive to fabricate and use. This paper presents a novel approach using Pt-decorated tin oxide (SnO〈sub〉2〈/sub〉) nanowires at different working temperatures to produce a virtual sensor array exploiting the thermal fingerprints of the different gases. With only one nanostructured material (Pt-SnO〈sub〉2〈/sub〉) and 5 temperature values, the system could qualitatively and quantitatively discriminate all the gasestested (all reducing gases). The sensor could detect selectively which gas is present (with an accuracy of 100%) at what concentration (with an overall average error of approximately 14%, down to 3.7% for benzene). The results showed that single metal oxide resistive nanosensors could achieve a good level of real selectivity exploiting the thermal fingerprints from a temperature gradient.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 279〈/p〉 〈p〉Author(s): Wallans T.P. dos Santos, Hatem M.A. Amin, Richard G. Compton〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A multilayer Carbon Black (CB) modified Glassy Carbon Electrode (GCE) is proposed, developed and optimized for Adsorptive Stripping Voltammetry (AdSV). The thick (up to 1000 monolayers) multilayer CB modification offers a significant enhancement in sensitivity for AdSV but not diffusive voltammetry. The detection of the stimulant selegiline, which is a prohibited drug for athletes in sports competitions, is used as model for application of the proposed electrochemical method in saliva samples. The analytical performance of the CB-GCE for detection of seligeline in authentic saliva samples revealed a limit of detection of 0.12 μmol L〈sup〉−1〈/sup〉 which is sufficiently low to allow a possible application of this fast method in the doping control of this drug.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 279〈/p〉 〈p〉Author(s): G.N. Gerasimov, V.F. Gromov, M.I. Ikim, O.J. Ilegbusi, L.I. Trakhtenberg〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The structure and conductometric sensing properties to hydrogen of In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-CeO〈sub〉2〈/sub〉 and SnO〈sub〉2〈/sub〉-CeO〈sub〉2〈/sub〉 nanocomposites were investigated. Addition of small amounts of CeO〈sub〉2〈/sub〉 to In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanocrystals is shown to result in a significant increase in the sensor response. On the other hand, addition of CeO〈sub〉2〈/sub〉 to SnO〈sub〉2〈/sub〉 matrix produces a sharp decrease in the sensor response, and at 3 wt% CeO〈sub〉2〈/sub〉 concentration, the response of the SnO〈sub〉2〈/sub〉-CeO〈sub〉2〈/sub〉 composite to hydrogen is practically absent. The difference between the sensor response of In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-CeO〈sub〉2〈/sub〉 and SnO〈sub〉2〈/sub〉-CeO〈sub〉2〈/sub〉 composites is shown to be mainly due to the different interactions between the CeO〈sub〉2〈/sub〉 additives and the In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 or SnO〈sub〉2〈/sub〉 matrix crystals in the composites. The probable mechanisms of the CeO〈sub〉2〈/sub〉 effect on sensor response of the composites are discussed.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 279〈/p〉 〈p〉Author(s): Xin Ting Zheng, Walter L. Goh, Peter Yeow, David P. Lane, Farid J. Ghadessy, Yen Nee Tan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Improved chemical library screens for drug modulators of a target protein are vital to advance precision medicine. Here, we describe an ultrasensitive dynamic light scattering (DLS) based biosensor using gold nanoparticles as plasmon-enhanced sensing probes to rapidly screen anticancer compounds. The nanobiosensor which consists of DNA-conjugated dumbbell-shaped gold nanoprobes can detect protein activities in drug-treated cells. We have validated the utility of our nanosensor to screen for compounds known to reactivate mutated tumor suppressor protein p53 for DNA binding in complex cellular context, which leads to significant increases in the hydrodynamic size of the nanoprobes through DLS measurement. This unique nanoplasmonic biosensor not only significantly enhances the DLS signal for specific biomolecular binding, but also effectively suppresses the background noise from irrelevant entities, which greatly improves sensitivity and reduces consumption of both sample and probe. In addition, a competition assay designed to evaluate the relative DNA binding affinities of p53 using the same sensing probes allows a concomitant assessment of responsive p53 pathways downstream or cell fate. Most critically, this nanosensor enables direct interrogation of endogenous protein activities following drug treatment in live cells, allowing simultaneous on-target validation during phenotypic screens. This DLS-based nanobiosensor is broadly applicable to other DNA binding molecules and/or proteins, and holds great potential for high-throughput screening campaigns utilizing both conventional and fragment-based compound libraries in drug discovery.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518317234-ga1.jpg" width="485" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Xiaoying Wang, Yanqun Shan, Miao Gong, Xin Jin, liangrui Lv, Meng Jiang, Jun Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel electrochemical sensor for ochratoxin A (OTA) based on the hairpin aptamer (HA) and double report DNA was constructed successfully. In the work, HA was chosen as the OTA recognition element and immobilized on the gold electrode (GE) 〈em〉via〈/em〉 Au-S. Au nanoparticles (AuNPs) labeled double report DNA (rDNA1 and rDNA2) were symmetrically hybridized with HA simultaneously. Compared to the single report DNA, the strategy can dramatically increase the amount of AuNPs on the electrode surface and the stability of the HA to prevent lodging. The signal amplification was further implemented by using trithiocyanuric acid (TCA) to aggregate the AuNPs. Thus, it was observed that the differential pulse voltammetry (DPV) response of AuNPs was significantly amplified 〈em〉via〈/em〉 multiple signal amplification strategy. When OTA was present, the HA was specifically combined with OTA to form the OTA-HA complex, which caused double report DNA to detach from the electrode, resulting in the decrease of the DPV response. The proposed electrochemical aptasensor can sensitively detect low concentrations of OTA by monitoring the OTA-dependent DPV intensity change. Under the optimized conditions, it exhibited wide linear ranges from 1 pg mL〈sup〉−1〈/sup〉 to 1 ng mL〈sup〉−1〈/sup〉 with a low detection limit of 0.5 pg mL〈sup〉−1〈/sup〉. The work provides a new idea for the various mycotoxins and even other substances detection at trace level.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518319257-ga1.jpg" width="334" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Tingting Zhou, Rui Zhang, Yubing Wang, Tong Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The key challenge to develop gas sensors with high performances lies in the novel design of superior functional materials for effective reactions between target gases and sensing layers. Metal–organic frameworks (MOFs) have emerged as versatile candidates for preparation of ideal nanostructured materials with controllable composition, various structures and tunable pore size. Herein, a series of Fe–based and Fe/Ni–based one–dimensional (1D) nanostructures using MOFs as templates were prepared systematically. As a result of the hollow structure and nanohybrid features, the optimized α–Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/NiFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 nanotubes can exhibit high specific surface area (118.03 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉) and provide a mass of active sites compared to individual components (α–Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanowires and NiFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 nanowires), which is beneficial to improve the response (R〈sub〉a〈/sub〉/R〈sub〉g〈/sub〉 = 23) to acetone vapors. In addition, the smart design also endows the sensor based on α–Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/NiFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 nanotubes with good selectivity, fast response time (4 s) and long–term stability (30 days). In this work, the advantages of 1D hollow heterogeneous materials will provide a new perspective of MOF–derived nanostructures for the particular application in acetone gas sensors.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518319014-ga1.jpg" width="329" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Xiaoxi Yuan, Nan Gao, Xuan Gao, Dongchao Qiu, Rui Xu, Zhaolong Sun, Zhigang Jiang, Junsong Liu, Hongdong Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, a nanopyramid boron-doped diamond (BDD) electrode is prepared by hydrogen-plasma treating conventional chemical vapor deposition BDD films. The nanopyramid grains are formed by a vaporization and secondary nucleation on BDD surface to test the trace level of an environmental hormone pollutant of 4-nonylphenol (4-NP). Voltammetry of 4-NP investigated on this electrode reveals the irreversible, adsorption-controlled, one-electron-and-one-proton involved oxidation process. The oxidation peak current is significantly evident even at low concentration of 4-NP (in the region of 1–100 nM) and the detection limit can be realized as low as 0.26 nM, which is lower than most previous reports. It is attributed to the more reaction sites provided by the high dense nanopyramids on the BDD surface and the hydrogen-terminated surface. Moreover, the electrode is reusable for the physical adsorption between 4-NP molecule and nanopyramid BDD. Taking into considering the unique properties of BDD, the corresponding electrodes show stability and specificity for detecting trace 4-NP molecules.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Pãmyla L. dos Santos, Vera Katic, Hugo C. Loureiro, Matheus F. dos Santos, Diego P. dos Santos, André L.B. Formiga, Juliano A. Bonacin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉3D printing has been reported as a remarkable technology for development of electrochemical devices, due to no design constraints, waste minimization and, most importantly, fast prototyping. The use of 3D printed electrodes for electroanalytical applications is still a challenge and demand efforts. In this work, we have developed low-cost and reproducible 3D-printed graphene electrodes for electrocatalytic detection of dopamine. Electrocatalytic features were enhanced after electrochemical pre-treatment. The oxidation and reduction at different potential ranges, in 0.1 mol L〈sup〉−1〈/sup〉 phosphate buffer solution (pH = 7.4), are used to modulate the structural and morphological characteristics of the electrodes. Since, the electrochemical properties of the electrodes, including electron transfer kinetic and the electrocatalytic activity, are strongly influenced by electronic properties and the presence of functional groups. Raman spectroscopy, SEM and AFM microscopes and electrochemical techniques were used to characterize the 3D electrodes before and after the electrochemical pre-treatments. Finally, the performances of the 3D-printed graphene electrodes were evaluated towards dopamine sensing. The best performance was achieved by oxidation at + 1.8 V 〈em〉vs.〈/em〉 SCE for 900 s and reduction from 0.0 V to -1.8 V 〈em〉vs.〈/em〉 SCE at 50 mV s〈sup〉−1〈/sup〉. The proposed sensor presented linear response from 2.0 μmol L〈sup〉−1〈/sup〉 to 10.0 μmol L〈sup〉−1〈/sup〉, with detection limit of 0.24 μmol L〈sup〉−1〈/sup〉.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518319609-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Jigna R. Bhamore, Sanjay Jha, Rakesh Kumar Singhal, Z.V.P. Murthy, Suresh Kumar Kailasa〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, we proposed a facile and green synthetic route for the fabrication of amylase encapsulated ultra-small fluorescent gold nanoclusters (amylase-Au NCs) for the detection of deltamethrin and glutathione (GSH) based on the “turn off” fluorescence quenching mechanism. A panel of characterizations was carried out to understand the electronic structure, morphology and surface chemistry of Au NCs. The obtained data revealed that the successful formation of amylase-Au NCs. The amylase capped Au NCs displayed excitation and emission bands at 383 and 660 nm, respectively with 7.9% quantum yield. The amylase-Au NCs acted as a fluorescent probe for selective and sensitive detection of deltamethrin and GSH and exhibited good linearity in the range of (0.01–5 μM) and (0.05–5 μM), with the detection limit 6 and 10 nM, respectively. The real sample applications of the probe were successfully established by analyzing deltamethrin and GSH in water, food and biological samples. Additionally, amylase-Au NCs were also used as a bio-imaging probe for 〈em〉Exophiala〈/em〉 sp. cells.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518319427-ga1.jpg" width="401" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 281〈/p〉 〈p〉Author(s): Giulio Maccaferri, Fabio Terzi, Zhenyuan Xia, Fabio Vulcano, Andrea Liscio, Vincenzo Palermo, Chiara Zanardi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Graphene oxide modified screen-printed electrodes have been tested as amperometric sensors for morphine determination. The results demonstrate that the arising of electrocatalytic processes ascribable to the graphene coating, combined with the use of a suitable cleaning procedure, allow the sensor to achieve higher sensitivity (2.61 nA ppb〈sup〉−1〈/sup〉) and lower limit of detection (2.5 ppb) with respect to those reported in the literature for similar devices.〈/p〉 〈p〉Due to very low detection limit found, the device is suitable to detect the presence of morphine in urine samples after a very simple and rapid pre-treatment of the matrix, allowing the removal of interfering species affecting the voltammetric responses. Tests performed in synthetic urine samples demonstrate that the presence of the electrocatalytic coating is mandatory in resolving the peak due to morphine oxidation in respect to uric acid. The sensor proposed is, thus, suitable to detect this drug even at concentration values below the cut-off levels defined by European and American regulations. These results allow us to propose the sensor for screening tests in portable devices, to be applied in systematic controls of drug abuses, e.g. in drivers and in men at work.〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Hongbo Zhu, Jinyan She, Menglian Zhou, Xudong Fan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We developed an automated and highly portable device for rapid and sensitive formaldehyde detection based on heart-cutting 2-dimensional gas chromatography. In this design, the air sample was first absorbed by a preconcentrator before it is injected into the 1st-dimensional column (Rtx〈sup〉®〈/sup〉-VMS). The partial elution from the 1st-dimensional column containing formaldehyde was re-injected into the 2nd-dimensional column (Rt〈sup〉®〈/sup〉 Q-BOND column) for further separation. The detection of formaldehyde was achieved by using a micro-helium dielectric barrier discharge photoionization detector that is able to ionize formaldehyde (ionization potential = 10.88 eV). Due to the use of many miniaturized components, the entire system has a weight of only 1.3 kg (excluding the helium cartridge) and dimensions of only 27 cm x 24 cm x 12 cm. It is capable of detecting formaldehyde down to 0.5 ppb (V/V) with a signal-to-noise ratio of 6 in only 11 min (including 6 min of sampling). Meanwhile, simultaneous separation and detection of other air pollution related toxic compounds, such as benzene, toluene, ethylbenzene, and xylene, was also demonstrated by the 1-dimensional column and a flow-through micro-photoionization detector. The device developed here should have a broad range of applications in environmental protection, industries, space exploration, and battlefield.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Hongxia Li, Rui Jin, Deshuai Kong, Xu Zhao, Fangmeng Liu, Xu Yan, Yuehe Lin, Geyu Lu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The fabrication of a convenient fluorescence-based immunoassay (FIA) for specific antigen attract increasing concern but remains a considerable challenge, especially the laborious synthesis of nanomaterials-antibody conjugates. Herein, we circumvent this drawback by introducing a specific fluorescence signal response procedure to commercially available alkaline phosphatase (ALP)-labeled conventional immunoassay for imidacloprid detection. In this FIA protocol, gold nanoclusters (AuNCs) can anchor on the surface of two-dimensional cobalt oxyhydroxide (CoOOH) nanoflakes to form nanocomposite, resulting in remarkable decrease of fluorescence intensity. The quenching effects can be effectively reversed by introducing ascorbic acid that can trigger the decomposition of CoOOH nanoflakes. Notably, the corresponding fluorescence response induced by ascorbic acid was related to ALP activities labeled on antibody. After competitive immunoreaction, the ALP-labeled antibodies were bounded to immobilized antigen, which can regulate the fluorescence change. Utilizing fluorescence switching of system, the 50% inhibition concentration (IC〈sub〉50〈/sub〉) value of FIA toward imidacloprid was obtained at 1.3 ng mL〈sup〉−1〈/sup〉 which was 60-fold-of-magnitude more sensitive than that of conventional ELISA (86.4 ng mL〈sup〉−1〈/sup〉). This FIA protocol not only develops new prospects for pesticide detection, but also opens up potent strategy of fluorogenic immunoassay.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Jin-Song Hu, Sheng-Ju Dong, Ke Wu, Xiao-Long Zhang, Jian Jiang, Jia Yuan, Ming-Dong Zheng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A pH and thermal stable three dimensional framework [Mg(ATDC)(H〈sub〉2〈/sub〉O)〈sub〉2〈/sub〉]〈em〉〈sub〉n〈/sub〉〈/em〉 (〈strong〉1〈/strong〉) (H〈sub〉2〈/sub〉ATDC = 2′-amino-1,1′:4′,1′'-terphenyl-4,4′'-dicarboxylate) with blue fluorescence has been successfully synthesized and characterized. The Mg-MOF contains 2D [Mg(COO)〈sub〉2〈/sub〉]〈em〉〈sub〉n〈/sub〉〈/em〉 sheet, which links ATDC〈sup〉2−〈/sup〉 to generate 3D framework with accessible -NH〈sub〉2〈/sub〉 groups, which could be beneficial to impact the reorganization on specific small molecules. Importantly, it is the first reported highly selective fluorescence Mg-MOF for sensing 2,4,6-Trinitrotoluene (TNT), and have the highest sensitivity for detecting Chromium(III) simultaneously through fluorescence quenching. Furthermore, the quenching mechanisms are mainly attributed to the photo-induced electron transfer and competitive absorptions between the excitation/emission of Mg-MOF and analytes, rather than the interactions between –NH〈sub〉2〈/sub〉 and analytes.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A pH and thermal stable 3D framework [Mg(ATDC)(H〈sub〉2〈/sub〉O)〈sub〉2〈/sub〉]〈em〉〈sub〉n〈/sub〉〈/em〉 (〈strong〉1〈/strong〉) as fluorescence sensor with accessible -NH〈sub〉2〈/sub〉 has been successfully synthesized and characterized. It is the first reported highly selective bi-responsive fluorescence Mg-MOF for sensing 2,4,6-Trinitrotoluene(TNT), and have the highest sensitivity for detecting Chromium(III) simultaneously through fluorescence quenching. The quenching mechanisms are mainly attributed to the photo-induced electron transfer and competitive absorptions between the excitation/emission of Mg-MOF and analytes, rather than the interactions between –NH〈sub〉2〈/sub〉 and analytes.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321415-ga1.jpg" width="478" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): JiaKai Wu, JingWei Ma, Hong Wang, DongMei Qin, Li An, Ying Ma, ZunTao Zheng, XiuDe Hua, TieLiang Wang, XuJin Wu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A quantitative method was developed for the rapid, visual detection of benzothiostrobin residue in strawberry using the conjugates of CdSe/ZnS (core/shell) quantum dots (QDs) and anti-benzothiostrobin antibody (IgG) based fluorescence lateral flow test strip (FLFTS). The IgG with a binding specificity to the target antigen benzothiostrobin-BSA (a conjugate of benzothiostrobin and bovine serum albumin) was labeled with the QDs to prepare the QD-IgG bioprobes. The primary strategy included the designation of three test lines (T lines), which were sprayed with different concentrations of the antigen. After the spiked samples were added to the sample pad for 15 min at 37 °C, the results were visualized with the unaided eye with using ultraviolet (UV) protective goggles under UV lamp with a detection limit of 25 μg/L. Moreover, the visual detection method together with a gel imager, could be used as a quantitative method. The cut-off values for the T line 1, 2, and 3 were 1200, 600, and 150 μg/L, respectively. So multi-concentration and visual detection of spiked samples had been achieved. At last, the detection results of the spiked samples by FLFTS were consistent with the results of the UPLC-MS/MS method.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518320938-ga1.jpg" width="487" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈p〉Rapid, visual and multi-concentration detection of benzothiostrobin residue in strawberry using the conjugates of CdSe/ZnS (core/shell) quantum dots (QDs) and anti-benzothiostrobin antibody (IgG) based fluorescence lateral flow test strip (FLFTS).〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Xingtao Wang, Minggang Zhao, Yawen Song, Qingyun Liu, Yongxing Zhang, Yunpeng Zhuang, Shougang Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The 3D ZnO/ZnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/graphene foam (ZZFO/GF) was successfully prepared by template method and hydrothermal process as a sensing platform for colorimetric detection of hydroquinone (HQ). It is found that the foam exhibited improved peroxidase-like activity that could quickly catalyze 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 and produced a blue color, which can be observed by naked eyes. And the HQ was detected by means of fading the color of the oxTMB, which is a sensitive and simple colorimetric method that is rarely used for detection of HQ. Therefore, a simple, sensitive and selective sensing platform was established. A good linear range from 0 to 150 μM and low detection limit of 3.75 μM was achieved. Furthermore, the materials could be easily recollected by applying a magnetic field. This method exhibited practical potential in environmental pollutant analysis and actual detection of HQ in local river water was achieved.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 282〈/p〉 〈p〉Author(s): Moon-Jin Cho, Soo-Young Park〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A ratiometric fluorescence glucose biosensor based on carbon dots (CDs) and rhodamine 6G (Rh6G) was developed both as an aqueous solution and as a crosslinked poly(acrylic acid) solid-state film. A ratiometric fluorescence color change was realized by fluorescence quenching due to the bienzymatic reaction of glucose oxidase (GOx) and horseradish peroxidase (HRP) with glucose. When excited at 360 nm, the blue fluorescence emission of the CDs, prepared by a solvothermal method with citric acid and ethylene diamine, was quenched by the bienzymatic reaction with glucose, whereas the fluorescence of Rh6G was inert to glucose. Thus, a ratiometric fluorescence color change from blue to green was observed as the glucose concentration increased. The optimized CD/Rh6G/GOx/HRP aqueous solution showed a linear range of 0.1–500 μM with a limit of detection (LOD) of 0.04 μM, good selectivity for glucose over the major ingredients in human blood and could be used with human blood serum. A stable solid-state biosensor film was fabricated by immobilization of CD/Rh6G/GOx/HRP in the hydrogel film prepared by ultraviolet curing of a mixture of acrylic acid and diacrylated poly(ethylene glycol) (70:30, w/w). Compared to the CD/Rh6G/GOx/HRP aqueous solution, the hydrogel film showed a similar ratiometric fluorescence color change, sensitivity (linear range of 0.5–500 μM with an LOD of 0.08 μM), and selectivity. Further, the solid-state glucose biosensor film was inherently stable and could be used whenever needed, overcoming the instability of the aqueous solution (owing to aggregation, enzyme denaturation, etc.). These ratiometric biosensors increase the ability to detect glucose using the naked eye compared to simple turn-on or turn-off modes. Thus, this approach expands the potential applications of CDs in biosensors to provide more convenient and practical detection methods.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518320094-ga1.jpg" width="490" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 282〈/p〉 〈p〉Author(s): Jiao Wang, Ziying Zhang, Xia Gao, Xiaodong Lin, Yaqing Liu, Shuo Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Lead ion (Pb〈sup〉2+〈/sup〉) is known as a major non-degradable environmental pollutant and is quite harmful to human health. In our investigation, a novel ratiometric fluorescent nanosensor with DNA-AgNCs as single fluorophore has been successfully constructed for ultrasensitive and specific detection of Pb〈sup〉2+〈/sup〉. The single-strand DNA templated silver nanoclusters present green emission, which can be converted into red emission after approaching a specific DNA segment by forming duplex with its complementary DNA strands (ds-DNA-AgNCs). The ds-DNA-AgNCs contains rA cleavage site of Pb〈sup〉2+〈/sup〉-dependent DNAzyme configuration. In the presence of Pb〈sup〉2+〈/sup〉, the specific DNA segment would be released from the ds-DNA-AgNCs, resulting in discoloration of DNA-AgNCs from red to green. Since Pb〈sup〉2+〈/sup〉 can successively cleave the rA site, the signal change from red to green emission is amplified. Thus, benefiting from the Pb〈sup〉2+〈/sup〉-dependent DNAzyme and the charming properties of DNA-AgNCs, the proposed platform exhibits a good linear relationship from 0.001 nM to 10 nM with a detection limit of 1.0 pM for Pb〈sup〉2+〈/sup〉 determination, which is lower than most of the reported Pb〈sup〉2+〈/sup〉 biosensors. Moreover, this sensitive ratiometric fluorescent probe exhibits excellent selectivity toward Pb〈sup〉2+〈/sup〉 detection in real samples, such as lake water, tap water, and human serum samples, illustrating the huge potential applications for complicated samples in the future.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 282〈/p〉 〈p〉Author(s): Anup Pandith, Kashi Raj Bhattarai, Ravi Kumara Guralamatta Siddappa, Han-Jung Chae, Young Jun Seo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A doubly armed hydrazone-based 〈strong〉FLRHYDDFP〈/strong〉 probe selectively detects Cu〈sup〉2+〈/sup〉 and pyrophosphate (PPi) ions through an colorimetric response-〈em〉“colorless → yellow → colorless〈/em〉”- as well as “〈em〉on-off-on〈/em〉” photonic switching response under physiological conditions in a sequential manner. The binding stoichiometries of the analytes Cu〈sup〉2+〈/sup〉 and PPi were 1:2 and 2:4 for 〈strong〉FLRHYDDFP〈/strong〉-Cu〈sup〉2+〈/sup〉 and Cu〈sup〉2+〈/sup〉/PPi, respectively. The sequential sensing ability of 〈strong〉FLRHYDDFP〈/strong〉 toward Cu〈sup〉2+〈/sup〉 and PPi, attributed to effective complexation-aided d→π* electron transfer (ET) from Cu〈sup〉2+〈/sup〉 to 〈strong〉FLRHYDDFP〈/strong〉 and intramolecular charge/electron transfer from 〈strong〉FLRHYDDFP〈/strong〉 to 〈strong〉FLRHYDDFP〈sup〉+〈/sup〉〈/strong〉, resulted in the formation of a non-symmetric Cu〈sup〉2+〈/sup〉 chelate that provided a yellow-colored solution with a significant bathochromic shift from 376 to 446 nm in the UV–vis spectrum and quenching in the emission spectrum. Upon addition of PPi, Cu〈sup〉2+〈/sup〉 was extruded from the complex, resulting in a revival of the fluorescence centered at 572 nm. Thus, sequential addition of Cu〈sup〉2+〈/sup〉 and PPi yielded a colorless–yellow–colorless transition under visible light and 〈em〉on-off-on〈/em〉 switching under 365-nm light (fluorescence). The lowest detection limits for Cu〈sup〉2+〈/sup〉 and PPi, when using colorimetric and fluorimetric methods, were in the sub-micromolar and nanomolar levels, respectively. By exploiting this PPi sensing strategy, invitro as well as endogenous alkaline phosphatase activity could be monitored effectively, as demonstrated by exploiting the intracellular production or residual PPi in human salivary glands (normal) and cancer cell lines.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518320689-ga1.jpg" width="211" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 282〈/p〉 〈p〉Author(s): Waseem Abbas, Naeem Akhtar, Qinglei Liu, Tengfei Li, Imran Zada, Lulu Yao, Raheela Naz, Wang Zhang, Muhammad Ehsan Mazhar, Di Zhang, Dongling Ma, Jiajun Gu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Excessive usage of phenolic compounds such as catechol (Cat-), cresol (Cre-) and 〈em〉p-〈/em〉nitrophenol (PNP) in food processing and pharmaceutical industry may lead to severe health issues including nerve cells disruption and even infertility. Thus, designing sensitive nanoscale electrochemical sensors to boost single screen signalling of these phenolic compounds from environmental samples is highly demanded. However, control monitoring and quantification of these phenolic compounds from real samples such as commercially available pesticides and insecticides is quite challenging because of their low concentration along with excess of co-existing interfering species. Herein, for the simultaneous electrochemical monitoring of these phenolic pollutants, we fabricate C-encapsulated three-dimensional Cu nano-pyramids (C@3DCu-PY) through a simple, scalable freeze-drying and carbonization process. The resulting hybrid contains 3D arrangement of controlled Cu nano-pyramids with atomic arrangement along all four lateral faces with sharp apex which result in exposition of greater fraction of Cu {111} catalytic active sites, large number of sp〈sup〉2〈/sup〉 carbon atoms, and maximum surface defects along with dipolar/quadrupolar radiative plasmons, thus offering highly sensitive and selective behaviour toward simultaneous monitoring of Cat-, cresol and PNP. The designed C@3DCu-PY electrode also shows fast diffusion and kinetics of ions compared to C@almond (AL)-like Cu nanoparticles (NPs) sample, thus indicating shape dependent efficacy of the designed electrode. Because of high sensitivity, the developed novel C@3DCu-PY electrode was successfully applied to monitor PNP from commercially available insecticide. The results demonstrated the potential of the designed electrode to be used in preventing serious health issue associated with phenolic pollutants.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 282〈/p〉 〈p〉Author(s): Jiali Zhu, Xiangquan Hu, Binsheng Yang, Bin Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉One aggregation-induced emission enhancement (AIEE) active compound based on α–cyanostilbenes and maleic anhydride group were synthesized. The “Turn-On” fluorescence recognition for H〈sub〉2〈/sub〉S was evaluated both in aqueous solution and cells. It was found that cyanostilbenes group acts as the first reactive site and maleimide group acts as the second site to H〈sub〉2〈/sub〉S. Supramolecular assembly with 〈em〉β〈/em〉-cyclodextrin successfully revealed the reaction mechanism of 3-state model.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 282〈/p〉 〈p〉Author(s): Ding Wang, Shimeng Huang, Huijun Li, Aiying Chen, Ping Wang, Jing Yang, Xianying Wang, Junhe Yang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, ultrathin WO〈sub〉3〈/sub〉 nanosheets were prepared by self-assembly approach and their phase and morphology were regulated by changing the heat treatment temperature. Then, g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 modified WO〈sub〉3〈/sub〉 nanosheets sensitive material was fabricated via a facile liquid ultrasonic mixing method. The microstructure, morphology, chemical composition, oxidation state and surface area of WO〈sub〉3〈/sub〉 nanosheets and g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/WO〈sub〉3〈/sub〉 nanocomposite were comparatively studied by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscope (TEM), X-ray Photoelectron Spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). Sensing performances of WO〈sub〉3〈/sub〉 nanosheets and g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/WO〈sub〉3〈/sub〉 composite with different g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 loading amount were investigated with acetone as a target gas. Compared to WO〈sub〉3〈/sub〉 nanosheets, the g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/WO〈sub〉3〈/sub〉 gas sensor exhibits good response, excellent selectivity, transient response and trace detection ability to acetone vapor. Effects of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 content on gas sensitivity were also investigated. The response (R〈sub〉a〈/sub〉/R〈sub〉g〈/sub〉) of the gas sensor based on 1 wt% g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/WO〈sub〉3〈/sub〉 was 35 toward 100 ppm acetone at 340 °C, which was about 300% higher than the response value of pure WO〈sub〉3〈/sub〉 sensor. The sensor also showed a fast response/recovery speed (9 s/3.8 s) and a wide linear detection range (from 0.5 ppm to 500 ppm). These unique sensing properties were attributed to the synergistic effects including the contribution of WO〈sub〉3〈/sub〉 ultrathin nanosheets, suitable crystal phase and porous surface, and the sensitization of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉, which increases the specific surface area and regulates the electrical properties. This work will contribute to the development of new acetone sensors and expand the application of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 composite materials.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Huan Wang, Meizhou Liu, Wanqiao Bai, Huiping Sun, Yan Li, Haiqiang Deng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, a novel and convenient electrogenerated chemiluminescence (ECL) biosensing method for the quantitative detection of 5-hydroxymethylcytosine (5-hmC) in genomic DNA was developed by employing thiolated anchor probe DNA to immobilize 5-hydroxymethylcytosine double-stranded DNA (5-hmC-dsDNA) and a ruthenium(II) complex-tagged reporter probe as an ECL probe. Briefly, the 5-hmC-dsDNA was firstly oxidized to 5-formylcytosine dsDNA (5-fC-dsDNA) by KRuO〈sub〉4〈/sub〉 in high yields. Subsequently, the thiolated anchor probe DNA is employed to help immobilize the 5-fC-dsDNA onto the gold electrode surface 〈em〉via〈/em〉 the Au-S bond. An ECL probe DNA, labeled with a signal transducer − Ru(bpy)〈sub〉2〈/sub〉(cbpy)NHS, hybridized with the anchor probe DNA on the electrode, resulting in an intensive ECL emission. The obtained ECL intensity was linearly proportional to the content of 5-hmC in the range from 0.0090% to 0.5761%, with the limit of detection calculated to be 0.0036% (S/N = 3). Finally, we applied the developed 5-hmC detection strategy in various mice tissues. It demonstrates that the content of 5-hmC measured by this method in different mice tissues vary significantly: 5-hmC is highest in brain and lowest in spleen. The success in assaying the mice tissues samples signifies its great promise in a broad range of practical applications for the quantitative detection of 5-hmC in genomic DNA.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Zhonglong Wang, Yan Zhang, Jie Song, Mingxin Li, Yiqin Yang, Xu Xu, Haijun Xu, Shifa Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The development of reliable method for detection of hypochlorite (ClO〈sup〉−〈/sup〉) 〈em〉in vivo〈/em〉 is of great importance to understand the precise roles of ClO〈sup〉−〈/sup〉 in a variety of pathological and physiological processes. Herein, three novel camphor-based fluorescence probes (〈strong〉2a〈/strong〉-〈strong〉2c〈/strong〉) for the ratiometric detection of ClO〈sup〉−〈/sup〉 were designed and synthesized, which exhibited both a distinct red shift of the fluorescence emission and a marked enhancement of the fluorescence intensity ratio in response to ClO〈sup〉−〈/sup〉. The probes 〈strong〉2a〈/strong〉-〈strong〉2c〈/strong〉 could selectively and sensitively detect ClO〈sup〉−〈/sup〉 with rapid response time, wide pH application range and low detection limit. The sensing mechanism was carefully confirmed by the ESI-MS, 〈sup〉1〈/sup〉H NMR and DFT studies. In addition, the cell imaging experiments demonstrated that the probes 〈strong〉2a〈/strong〉-〈strong〉2c〈/strong〉 could be successfully applied to imaging ClO〈sup〉−〈/sup〉 in living cells.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092540051832224X-ga1.jpg" width="375" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Zayakhuu Gerelkhuu, Dasom Jung, Bui The Huy, Salah M. Tawfik, Maxwell L. Conte, Eric D. Conte, Yong-Ill Lee〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We developed a novel optical sensor for sensitive and selective detection of catecholamines based on upconversion nanoparticles (UCNPs) decorated with different metal ions (UCNP-Me〈sup〉n+〈/sup〉). 1,2-ethanedithiol was chosen as a surface additive to synthesize the NaLuGdF〈sub〉4〈/sub〉:Yb〈sup〉3+〈/sup〉/Er〈sup〉3+〈/sup〉 UCNPs by one-step at 200 °C. The as-prepared UCNPs exhibited a strong emission under the continuous excitation at 980 nm. It was found that catecholamines could be more effectively detected in the presence of UCNP-Fe〈sup〉3+〈/sup〉, whereas, dopamine and epinephrine were detected selectively using UCNP-Li〈sup〉+〈/sup〉 and UCNP-Cu〈sup〉2+〈/sup〉 sensors, respectively. Under the optimum conditions, the limit of detections (LODs) for catecholamines, dopamine, and epinephrine are 2.8, 2.5, and 2.4 nM, respectively, with good linearity in the range of 5–320 nM for total catecholamines and 5–30 nM for dopamine and epinephrine. The developed method has been successfully applied to detect dopamine and epinephrine in human urine samples with good accuracy and satisfactory recovery.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092540051832255X-ga1.jpg" width="265" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Yingyot Poo-arporn, Saithip Pakapongpan, Narong Chanlek, Rungtiva P. Poo-arporn〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A new disposable electrochemical sensor for rapid determination of ractopamine (RAC) is developed based on the use of a magnetic screen-printed electrode (MSPE) modified with an iron oxide magnetic nanoparticles doping on reduced graphene oxide (Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉/rGO). Morphology, structure and composition of nanocomposites were characterized by TEM, x-ray absorption spectroscopy (XANES) and x-ray photoelectron spectroscopy (XPS). XANES results indicated that the prepared nanocomposites exhibited the magnetic behavior, and the original structure of Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 NPs was displayed after being successfully doped on the rGO. XPS was used to confirm the chemical compositions of GO, GO doped with Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 and Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉/rGO reduced by glucose. The electrochemical and electrocatalytic characteristics of the modified MSPE were recorded using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) and the factors that affected the performance of the sensor were also optimized. The peak currents obtained by DPV increased linearly with the increasing of the concentration of RAC and the sensor had a detection range over the concentration ranges of 0.05–10 and 10–100 μM, with a detection limit of 13 nM (S/N = 3). Due to the Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉/rGO promoting the electron transfer, and raising the sensitivity of the sensor, the proposed disposable sensor displayed a good sensitivity, stability and reproducibility and robust operation in spiked real pork samples.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322408-ga1.jpg" width="498" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Ruya Guo, Siyuan Wang, Fengchun Huang, Qi Chen, Yanbin Li, Ming Liao, Jianhan Lin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rapid detection of foodborne pathogens is of great significance for ensuring food safety. In this study, a portable biosensor was developed for rapid and sensitive detection of 〈em〉Salmonella〈/em〉 Typhimurium using magnetic nanoparticle immunoseparation, nanocluster signal amplification and smartphone image analysis. The magnetic nanoparticles were conjugated with the monoclonal antibodies by biotin-streptavidin system for specifically capturing the target to form the magnetic bacteria. The polyclonal antibodies and glucose oxidase (GOx) were incubated with calcium chloride to synthesize the immune GOx-nanoclusters (GNCs) for reacting with the magnetic bacteria to form the nanocluster bacteria. The GNCs on the nanocluster bacteria were used to catalyze the glucose into hydrogen peroxide, which was measured using the peroxide test strip. The image of the strip was collected and analyzed using the Hue-Saturation-Lightness color space based smartphone APP for the determination of the target bacteria. This proposed biosensor was able to detect 〈em〉Salmonella〈/em〉 Typhimurium with the linear range of 10〈sup〉1〈/sup〉–10〈sup〉5〈/sup〉 CFU/mL and the low detection limit of 1.6 × 10〈sup〉1〈/sup〉 CFU/mL. The mean recovery of 〈em〉Salmonella〈/em〉 Typhimurium in the spiked chicken samples was 99.8%. This biosensor has the potential to provide a simple, portable and low-cost method for rapid and in-field detection of 〈em〉Salmonella〈/em〉 Typhimurium in foods.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Cheng-Yu Lee, Chi-Hsiang Liao, Jen-Te Tso, You-Zung Hsieh〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A light-induced photochemical biosensor was developed for the analysis of inorganic pyrophosphatase (PPase). PPase hydrolyzes pyrophosphate (PPi) into two independent 〈em〉o〈/em〉-phosphate ions. Two PPi units can chelate a copper ion (Cu〈sup〉2+〈/sup〉), forming a PPi–Cu〈sup〉2+〈/sup〉–PPi complex and preventing the Cu〈sup〉2+〈/sup〉 triggers other reactions. A transparent indium tin oxide (ITO) electrode was coated with a layer of CdS quantum dots (QDs), and then 3,4-diaminobenzoic acid (DBA) was deposited as the anchor. A solution of the PPi–Cu〈sup〉2+〈/sup〉–PPi complex and 〈em〉o〈/em〉-phenylenediamine (OPD) was mixed with the analytical sample and then a drop of the mixture was placed on the modified ITO electrode. In the absence of PPase, no reaction occurred between OPD and DBA. A photocurrent was obtained upon excitation of the CdS QDs under light. In the presence of PPase, Cu〈sup〉2+〈/sup〉 was released from the complex, triggering the reaction of OPD with DBA on the electrode surface, thereby shielding the CdS QDs from excitation by the light. The observed photocurrent decreased. The difference in the two measured photocurrents corresponded to the activity of PPase. This photochemical biosensor had excellent sensitivity for PPase in the range from 0.8 to 5000 mU, with a limit of detection of 0.41 mU.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Mingshu Ye, Ying Yu, Bixia Lin, Yi Cai, Yujuan Cao, Manli Guo, Debin Zhu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, copper nanoclusters (CuNCs) were synthesized via a one-step method using glutathione as the reducing agent and stabilizer, then characterized by means of various methods. The prepared CuNCs with the average diameter of 2.1 nm had excitation and emission wavelengths at 360 and 615 nm. Further, it was found that Al〈sup〉3+〈/sup〉 could trigger the aggregation of CuNCs causing a remarkable fluorescence enhancement of the system. However, owing to the stronger coordination between Al〈sup〉3+〈/sup〉 and pyrophosphate (PPi), CuNCs/Al〈sup〉3+〈/sup〉 was disaggregated with the addition of PPi, resulting in a significant fluorescence quench of system. When PPase was present, PPi was consumed by PPase, which inhibited the disaggregation of CuNCs. Based on the principle of Al〈sup〉3+〈/sup〉 and PPi inducing aggregation/disaggregation of CuNCs accompanied by fluorescence enhancement/quenching, a novel method was established for fluorescence "turn-on-off-on" detection of PPase activity. The detection limit of PPase was determined to be 1.3 mU mL〈sup〉−1〈/sup〉 in the linear range of 3.0–40.0 mU mL〈sup〉−1〈/sup〉. The established method was used to detect the positive samples of rat serum with satisfactory spiked recoveries, and applied for the screening of inhibitors.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322111-ga1.jpg" width="317" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Jingjing Guo, Yan Wang, Min Zhao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A new enzyme–inorganic hybrid nanoflower was synthesized and used to achieve a self-activated cascade reaction for glucose detection, and a visual analytical device for screening of the diabetes was also developed. The glucose oxidase–ferrous phosphate hybrid nanoflowers (GOx–Fe〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉·8H〈sub〉2〈/sub〉O HNFs) with two types of morphologies were obtained, in which the nanostructures with hydrangea-like morphology were selected for the subsequent study owing to their excellent catalytic activity. The HNFs exhibited significantly enhanced catalytic activity, stability and reusability compared with free enzymes. In virtue of their good catalytic properties, the HNFs realized the self-activated cascade detection of glucose by integrating two different types of enzymes. First, GOx catalyzed glucose to produce H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 and gluconic acid. Then, the generated gluconic acid decreased pH of the reaction system to about 4 which was the optimum pH for Fe〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉·8H〈sub〉2〈/sub〉O to arouse its peroxidase-like activity. The in-situ formed H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 was finally catalyzed by adjacent Fe〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉·8H〈sub〉2〈/sub〉O to oxidize 3,3’,5,5’-tetramethylbenzidine (TMB), resulting in a significant color change. This proposed assay has been successfully achieved the glucose detection in human serum with good accuracy and reproducibility. Moreover, a new visual analytical device for screening of the diabetes was developed, which offered a new strategy for the field analysis of glucose.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322214-ga1.jpg" width="340" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Xueqing Wang, Wensheng Tan, Yong Wang, Datong Wu, Yong Kong〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, electrocatalytic sensing of gallic acid (GA) with poly(〈em〉m〈/em〉-phenylenediamine) (PmPD) electrodeposited on the nanocomposites of palygorskite (Pal) and ionic liquid (IL) was reported. The PmPD/Pal-IL modified electrode showed a low limit of detection (LOD) of 0.28 μM and a wide linear range from 1.0 μM to 300 μM for electrochemical sensing of GA due to the synergistic effects of PmPD, Pal and IL. That is to say, electrocatalysis of PmPD, preconcentration ability of Pal and ionic conductivity of IL contributed to the sensitive determination of GA. In addition, the fabricated PmPD/Pal-IL also exhibited high selectivity with little interferences from common organic compounds and inorganic cations, high storage stability and reproducibility in the determination of GA. Finally, the proposed GA sensor was applied in the determination of GA in real food samples, and the results demonstrated the potential of the prepared PmPD/Pal-IL as a promising GA sensor for rapid and accurate determination of GA in foodstuffs.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322536-ga1.jpg" width="370" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Wenxiu Li, Simin Zhou, Liangliang Zhang, Zhengmin Yang, Hua Chen, Wenqiang Chen, Jiangke Qin, Xingcan Shen, Shulin Zhao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrogen polysulfides (H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉, n ≥ 2) is an important reactive sulfur species, which has been demonstrated to be more effective than H〈sub〉2〈/sub〉S in some biological events. However, the studies focused on the chemical biology of H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 are still at the initial stage. One critical barrier is the lack of effective tools for H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 monitoring in biosystems. Here, we synthesized a red fluorescence probe 〈strong〉PZC-S〈sub〉n〈/sub〉〈/strong〉 to detect H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉, which shows high sensitivity, good selectivity and low cytotoxicity. The red emission and large Stokes shift of 〈strong〉PZC-S〈sub〉n〈/sub〉〈/strong〉 facilitate the in vivo application, which was demonstrated by imaging exogenous and endogenous H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 in living RAW 264.7 cells and zebrafish. The results imply that 〈strong〉PZC-S〈sub〉n〈/sub〉〈/strong〉 can be further used as a promising fluorescence probe in the study of H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉-realted biological process.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322251-ga1.jpg" width="285" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Suresh Kumar Chakkarapani, Yucheng Sun, Seong Ho Kang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A fluorescence-free ultrasensitive norovirus nanoimmunosensor was investigated based on gradient-fitting super-localization by three-dimensional (3D) dual-view light sheet microscopy (DV-LSM). A highly contagious norovirus was detected by immunoreaction with 100-nm gold nanospots (AuNSs) and 40-nm silver nanoparticles (AgNPs) as imaging probes. Dual-view setup was added to the optical path to simultaneously image AgNP-labelled norovirus and AuNSs in real time. A cylindrical lens and dual-view identified axial distance differences between AuNS and AgNP images as a function of an elliptically distorted point spread function (PSF). Differences between PSFs in each plane at 10 nm slicing intervals were distinguished by gradient-fitting algorithm-based super-localization. This approach showed highly enhanced detection sensitivity and super-localization in the axial direction for norovirus. The axial distance between AuNS and AgNP in norovirus immnosensor was 23 ± 3 nm for 7.8 zM, and the distance increased with increased concentration. The method had an excellent limit of detection (LOD) of 7.8 zM with a wide linear dynamic range of 7.8 zM–240 aM. The LOD was 106 to 2,300,000 times lower than previous methods. Norovirus was detected in lettuce leaf extraction at 14.3 zM with 99.87% recovery. The 3D DV-LSM method with gradient-fitting super-localization was an effective method for ultra-trace norovirus detection at the single-molecule level with highly precise axial resolution.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A nanoimmunosensor based on concurrent axial gradient super-localization with 3D light sheet microscopy correlated dual-detection mode and cylindrical lens for hypersensitive norovirus detection.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322378-ga1.jpg" width="324" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Haipo Dai, Nana Feng, Jiwei Li, Jie Zhang, Wei Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A chemiresistive humidity sensor based on chitosan (CS)/zinc oxide/single-walled carbon nanotube (SWCNT) composite was developed. The sensor film was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The humidity sensing properties were investigated in a wide range of relative humidity (RH) (11%–97%) at room temperature. The SWCNT response to humidity was significantly improved with the aid of conjugate material in the composite, especially the CS. The composite also exhibited good reproducibility. The RH-dependent relationship revealed that the sensing response corresponded to the water sorption characteristic of CS. The sensing mechanism was attributed to the swelling effect of CS surrounding the nanotubes through which the hopping conduction path between nanotubes changed.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Hyeon Jin Choi, Chang Su Lim, Myoung Ki Cho, Ji Su Kang, Soo Jin Park, Sang Myun Park, Hwan Myung Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrogen polysulfide (H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉, n〉1), which is primarily generated during the crosstalk between H〈sub〉2〈/sub〉S and reactive species (ROS and RNS), is receiving increasing attention in biochemical research. H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 is mostly generated in the mitochondria, and abnormal mitochondrial function and oxidative stress are directly related to many disorders including Parkinson's disease (PD). We now report a two-photon fluorescent probe (〈strong〉SPS-M1〈/strong〉) for in situ detection of H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 and its application to a PD model to account the H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 levels. The probe exhibited selective and fast response to H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 along with a marked blue-to-green color change. 〈strong〉SPS-M1〈/strong〉 is sensitive enough to quantitative detection of endogenous H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 content in mitochondria using two-photon microscopy (TPM). Ratiometric TPM imaging of live neurons and brain slices using 〈strong〉SPS-M1〈/strong〉 revealed that H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 production is increased to a greater extent in the A53 T α-synuclein (α-syn) overexpressing model than in the wild-type control. These findings suggest that the interactions of H〈sub〉2〈/sub〉S and the increased ROS caused by α-syn overexpression may generate more H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉. By employing our recently published TP probe for mitochondrial H〈sub〉2〈/sub〉S, we also found the relationship between the H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 and H〈sub〉2〈/sub〉S; increased H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 and decreased H〈sub〉2〈/sub〉S levels, indicating that H〈sub〉2〈/sub〉S and H〈sub〉2〈/sub〉S〈sub〉n〈/sub〉 may play a significant role in the pathogenesis of PD. This result may be useful to biomedical studies, including PD.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322044-ga1.jpg" width="362" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Yingzhe Liu, Naotomo Tottori, Takasi Nisisako〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Alginate-based hydrogels are widely used in the biomedical and chemical fields, and their size and shape are significant to their applications like drug delivery and cell encapsulation. Here, we report a microfluidic external gelation process using an on-chip calcium chloride (CaCl〈sub〉2〈/sub〉) emulsion reactant for producing highly spherical calcium alginate (Ca-alginate) hydrogel particles. The microfluidic channels were two serial cross-junctions fabricated on quartz glass. Monodisperse sodium alginate (Na-alginate) droplets with diameters greater or smaller than the opening (ranging from 176 μm to 225 μm) with a coefficient of variation (CV) less than 3% were successfully generated at the upstream cross-junction; they then reacted with the CaCl〈sub〉2〈/sub〉 emulsion at the downstream cross-junction, forming Ca-alginate hydrogels. The effects of the fraction of the aqueous phase in the reactant CaCl〈sub〉2〈/sub〉 emulsion and the flow rates of continuous and emulsion phases on the roundness of the obtained hydrogels were studied. By optimizing the parameters above, monodisperse spherical hydrogel particles were obtained with diameters ranging from 147 μm to 176 μm with CVs around 5%. The synthesis of magneto-responsive hydrogels with asymmetric Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 coatings was also demonstrated.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Hong Pan, Shuo Xu, Yonghong Ni〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Zn-Hbtc-BPY/Ln〈sup〉3+〈/sup〉 fluorescent microspheres were successfully synthesized via a simple two-step solution route. First, the spherical Zn-Hbtc-BPY microstructures were prepared at room temperature employing zinc nitrate as the metal source, trimesic acid and bipyridine as the mixed ligands. Then, spherical Zn-Hbtc-BPY microstructures were sunk in an ethanol solution containing Ln〈sup〉3+〈/sup〉 ions (Ln〈sup〉3+〈/sup〉 = Eu〈sup〉3+〈/sup〉, Tb〈sup〉3+〈/sup〉, Eu〈sup〉3+〈/sup〉/Tb〈sup〉3+〈/sup〉) at room temperature to form Zn-Hbtc-BPY/Ln〈sup〉3+〈/sup〉 fluorescent microspheres. Experiments showed that the obtained Zn-Hbtc-BPY/Ln〈sup〉3+〈/sup〉 microspheres exhibited tunable optical properties under the excitation of the light with various wavelengths; and that white light emission could be achieved under the proper excitation wavelength. It was found that L-tryptophan could cause the characteristic emission increase/decrease at 370/546 nm of the as-prepared Zn-Hbtc-BPY/Tb〈sup〉3+〈/sup〉 fluorescent microspheres. As a result, the fluorescence intensity ratio between the above wavelengths (I〈sub〉370〈/sub〉/I 〈sub〉546〈/sub〉) could be tuned by the concentration of L-tryptophan. Since the other amino acids did not interfere with the above phenomenon, the as-obtained Zn-Hbtc-BPY/Tb〈sup〉3+〈/sup〉 fluorescent microspheres have potential application as the fluorescence probe for the selective detection of L-tryptophan in the aqueous system with a detection limit of 15.2 μM.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Fluorescent Zn-Hbtc-BPY/Ln〈sup〉3+〈/sup〉 microstructures employed for highly selective detection of 〈span〉l〈/span〉-tryptophan are successfully prepared by a simple two-step room-temperature route.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321634-ga1.jpg" width="283" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Nileshi Saraf, Swetha Barkam, Madison Peppler, Anna Metke, Abraham Vázquez-Guardado, Sushant Singh, Clarence Emile, Adrian Bico, Corey Rodas, Sudipta Seal〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Limonin is a biomolecule which is responsible for the bitter taste in citrus fruits such as oranges, grapes etc. The abnormally high level of limonin is indicative of citrus greening disease which results in stunted tree growth and affects fruit quality in terms of nutritional value, taste, texture and aroma. Therefore, quantification and detection of limonin is crucial for an early management of citrus greening disease to save the multibillion dollar citrus industry. To this end, an organic electrochemical transistor (OECT) functionalized with Ceria Nanoparticles (CNPs) as transducer has been developed to detect ultralow concentration of limonin. The device exhibited high sensitivity (detection limit: 10 nM) and selectivity towards limonin with response time in seconds. The detection is attributed to the switching of Ce〈sup〉3+〈/sup〉 to Ce〈sup〉4+〈/sup〉 at the gate electrode which decreases the overall effective gate voltage resulting in an increase in the output current. The increase in output current was observed in transfer characteristics as well as time-current curve. In-situ spectro-electrochemical studies were also performed to analyse the change in oxidation state of CNPs in the presence of limonin. This novel biosensor successfully detected the increase in limonin in infected juice samples as compared to healthy ones with a sensitivity of ∼10 μA/μM. A rapid, easy and on-site testing tool to detect and quantify the amount of limonin for an early detection of citrus greening disease has been demonstrated for the first time.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Microsensor based on Ceria nanoparticles to detect citrus greening disease (HLB) using an Organic Electrochemical transistor platform.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321865-ga1.jpg" width="227" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Byeongyeon Kim, Suyeon Shin, Yujin Lee, Changyong Um, Dongwon You, Hoyoung Yun, Sungyoung Choi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A residual white blood cell (rWBC) count is the remaining concentration of WBCs in leucodepleted blood products, and is an important quality-assurance parameter for blood transfusion. Current cell-counting methods rely on a small test volume that can result in the inherent statistical error involved in counting rWBCs present at low concentrations or manual sample preparation that increases experimental workload. To address these critical challenges, we present a microfluidic rWBC counter that (i) rapidly enriches rWBCs to reduce a sample volume to be examined and thus enable high-throughput cell counting, and (ii) integrates an on-chip cell staining module that contains reagent-containing hydrogel patches and allows the controlled release of a staining reagent. With these novel features, we demonstrated high-throughput rWBC counting by achieving reliable cell counting over a dynamic range of 0.1–26.8 rWBCs/μL and processing a blood sample at a high throughput of 400 μL per minute. In addition, we successfully performed sample preparation-free counting of rWBCs by integrating the on-chip staining module into the rWBC counter, offering sample-in-answer-out capability. On the basis of the results, the rWBC counter represents a promising tool for the quality control of WBC depletion and improvement in the safety of blood transfusion.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Mariana Silva, Sonia Morante-Zarcero, Damián Pérez-Quintanilla, Isabel Sierra〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, hexagonal mesoporous silica (HMS) and amino-functionalized HMS (HMS-NH〈sub〉2〈/sub〉) were prepared and incorporated into carbon paste electrodes (CPEs) to obtain electrochemical sensors for pindolol (Pin), acebutolol (Ace) and metoprolol (Met) determination in waters by voltammetric techniques. The materials were characterized and they showed high specific surface area, large pore volume and a quasi-spherical morphology. Firstly, the electrochemical behaviour of the modified CPEs was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Then, the dependence of the current intensity with the electrolyte support (type and pH) and the accumulation time was investigated to optimize the experimental conditions for simultaneous β-blockers determination by DPV. Results showed that the sensor modified with functionalized silica (NH〈sub〉2〈/sub〉-HMS-CPE) exhibited strong adsorption activity, showing three well-defined peaks in the differential pulse voltammograms, that appeared at about +0.85 V (Pin), +1.11 V (Ace) and +1.45 V (Met). This fact can be attributed to the high surface area of the material, with a 3 D wormhole-like channel structure that favoured excellent pore accessibility, and the synergistic effect produced by the grafted amino groups producing hydrogen bond interactions with the oxygen atoms of the target β-blockers. The prepared sensor exhibits good reproducibility, wide linear ranges and very low detection limits (0.1, 0.046 and 0.23 μmol L〈sup〉−1〈/sup〉 for Pin, Ace and Met, respectively). Moreover, the NH〈sub〉2〈/sub〉-HMS-CPE was successfully applied for the simultaneous determination of Pin, Ace and Met in tap, mineral, river and sewage effluent waters with simple sample treatment (recoveries 97–112%).〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Lili Xiao, Qi Chen, Lin Jia, Qing Zhao, Jin Jiang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Co〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉 is recently reported to be an attractile electrocatalyst in biomonitoring oxygen/hydrogen evolution due to its biocompatibility and high stability. In this work, a weakly networked cobaltous phosphate (net-Co〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉) decorated with defective nitrogen-doped reduced graphene oxide (net-Co〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉/NG) was facilely prepared through ultrasonic exfoliation. A glassy carbon electrode (GCE) modified with the net-Co〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉/NG (net-Co〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉/NG) was fabricated as a non-enzymatic glucose sensor. The net-Co〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉/NG/GCE exhibited a ultra-high sensitivity of 2307 μA mM〈sup〉−1〈/sup〉 cm〈sup〉-2〈/sup〉, a low detection limit of 1.0 μM (at a signal-to-noise ratio of 3, S/N = 3). The excellent electrochemical performances of net-Co〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉/NG/GCE for glucose oxidation were attributed to the superior catalytic activity of net-Co〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉 with a weakly bonding structure because of solvent exfoliation, and the high conductivity of defective NG sheets. Moreover, the net-Co〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉/NG/GCE was successfully used to detect glucose in human serum, and the good recoveries made net-Co〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉/NG a very promising sensing material in clinical lab.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321336-ga1.jpg" width="358" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Tianrong Zhan, Xia Tian, Guiyan Ding, Xien Liu, Lei Wang, Hongni Teng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We have developed a facile quaternarization strategy to an ultrathin lamellar g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 ionic liquid nanostructure (IL-CNNS) 〈em〉via〈/em〉 a nucleophilic substitution between the tertiary amino groups in tri-〈em〉s〈/em〉-triazine subunits and n-butyl bromide. After functionalization, the obtained IL-CNNS composite exhibits the enhanced conductivity, dispersibility and stability owing to the formation of IL structure. This composite has been characterized by several spectroscopic techniques (FT-IR, XRD, XPS, TGA and TEM). The IL-CNNS modified electrode displays the larger effective surface area and the faster electron transfer rate, hence resulting in the superior electrocatalytic activity toward 2,4-Dichlorophenol (2,4-DCP). Under the optimal conditions, the proposed 2,4-DCP sensor gives rise to the wide linear range from 0.02 to 160 μM with a low detection limit (6.21 nM, S/N = 3) by amperometric method. The developed sensor has been applied to detect 2,4-DCP in water samples with satisfactory recoveries and stability. This quaternarization strategy may open up a new avenue to fabricate the layered carbon nitride IL nanostructure for electrochemical sensing applications.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321877-ga1.jpg" width="217" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Niels Peter Revsbech, Emilio Garcia-Robledo, Steffen Sveegaard, Mikkel Holmen Andersen, Kurt Vesterager Gothelf, Lars Hauer Larsen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A simple method to measure dissolved CO〈sub〉2〈/sub〉 at a microscale would be beneficial for many scientific and medical applications. A simple amperometic microsensor for CO〈sub〉2〈/sub〉 with a 20–100 μm wide tip was developed by placing a layer of acidic O〈sub〉2〈/sub〉 trap solution containing Cr〈sup〉2+〈/sup〉 in front of a Clark-type electrochemical sensor. The Clark-type sensor contains a Ag cathode in an ionic liquid, and also a Ag guard cathode behind the sensing cathode to prevent interference from reducible contaminants in the ionic liquid. The constructed sensors exhibited linear response over relatively large intervals of CO〈sub〉2〈/sub〉 partial pressure, but for CO〈sub〉2〈/sub〉 partial pressures of 〈 20 Pa the response was only about 60% of that observed at 20–1000 Pa. The slope of the calibration curve at 2–6 kPa was about 80% of the slope from 0 to 1 kPa. A high baseline signal caused by water diffusing through the membrane into the ionic liquid was avoided by making very conical sensors so that the water concentration around the cathode was kept low by diffusional transport into the bulk reservoir of ionic liquid, but elevated zero currents by a factor of about two was often observed for sensors more than 1 month old. The lifetime of the sensor by continuous operation can be more than 4 months, but with a slow decrease in sensitivity that may be caused by lower membrane permeability. Use of the sensor was demonstrated by measuring CO〈sub〉2〈/sub〉 dynamics in the thallus of a red algae along with variations in O〈sub〉2〈/sub〉 and pH.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Ming Liu, Jinglan Kan, Yuqing Yao, Yunqian Zhang, Bing Bian, Zhu Tao, Qianjiang Zhu, Xin Xiao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, we report the facile preparation of two solid luminescent materials made from cucurbit[10]uril-based porous supramolecular assemblies, from simple precipitation of cucurbit[10]uril (Q[10]) in HCl solution (A) or HNO3 solution (B). Loading Q[10]-based porous supramolecular assemblies 〈strong〉A〈/strong〉 or 〈strong〉B〈/strong〉 with various fluorophore guests (〈strong〉FG〈/strong〉s), including dyes and fused ring compounds, to yield solid luminescent materials (〈strong〉FG〈/strong〉@〈strong〉A〈/strong〉s and 〈strong〉FG〈/strong〉@〈strong〉B〈/strong〉s) that exhibited fluorescence enhancement or colour changing fluorescence emission. Moreover, these solid luminescent materials could respond to certain volatile organic compounds, demonstrating promise as solid sensors.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Loading Q[10]-based porous supramolecular assemblies A or B with various fluorophore guests (FGs), including dyes and fused ring compounds, to yield solid luminescent materials (FG@As and FG@Bs) that exhibited fluorescence enhancement or colour changing fluorescence emission. Moreover, these solid luminescent materials could respond to certain volatile organic compounds, demonstrating promise as solid sensors.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321439-ga1.jpg" width="243" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Chuanrui Guo, Liang Fan, Chenglin Wu, Genda Chen, Wei Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉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.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Vanoushe Rahemi, Stanislav Trashin, Zainab Hafideddine, Vera Meynen, Sabine Van Doorslaer, Karolien De Wael〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Titanium dioxide (TiO〈sub〉2〈/sub〉) is a popular material as host matrix for enzymes. We now evidence that TiO〈sub〉2〈/sub〉 can accumulate and retain reactive oxygen species after treatment by hydrogen peroxide (H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉) and support redox cycling of a phenolic analyte between horseradish peroxidase (HRP) and an electrode. The proposed detection scheme is identical to that of second generation biosensors, but the measuring solution requires no dissolved H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉. This significantly simplifies the analysis and overcomes issues related to H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 being present (or generated) in the solution. The modified electrodes showed rapid stabilization of the baseline, a low noise level, fast realization of a steady-state current response, and, in addition, improved sensitivity and limit of detection compared to the conventional approach, 〈em〉i.e.〈/em〉 in the presence of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 in the measuring solution. Hydroquinone, 4-aminophenol, and other phenolic compounds were successfully detected at sub-μM concentrations. Particularly, a linear response in the concentration range between 0.025 and 2 μM and LOD of 24 nM was demonstrated for 4-aminophenol. The proposed sensor design goes beyond the traditional concept with three sensors’ generations offering a new possibility for the development of enzymatic sensors based on peroxidases and the formation of ROS on titania after treatment with H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321567-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Chengmei Jiang, Yao Yao, Yalu Cai, Jianfeng Ping〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Single-walled carbon nanohorns (SWCNHs) was utilized as an ion-to-electron transducer to fabricate all-solid-state ion-selective electrodes (ISE) for the first time. To evaluate the performance of developed SWCNHs-based calcium ISE, various electrochemical experiments were carried out. A Nernstian response (29.69 ± 0.24 mV/decade, 〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.9996) was acquired across a broad linear range between 10〈sup〉−6〈/sup〉 and 10〈sup〉−2〈/sup〉 M, and the detection limit of 10〈sup〉−6.1〈/sup〉 M was achieved in the meantime. Additionally, water layer test and reversed chronopotentiometry were used to estimate the long-term and short-term stability of SWCNHs-based ISE, respectively, indicating SWCNHs is capable of enhancing potential stability on account of its hydrophobicity. Furthermore, a SWCNHs-based reference electrode (RE) was fabricated by directly coating a photo-polymerised reference membrane (RM) onto a SWCNHs modified electrode. Results demonstrated that the SWCNHs-based RE exhibited slight potential fluctuation for common ions with different charges over a wide concentration range of calibration. Based on these superior results, an integrated all-solid-state SWCNHs-based potentiometric sensing device combined SWCNHs-based ISE and SWCNHs-based RE was constructed for detecting calcium, which shows a Nernstian response with a slope of 27.14 mV/decade. This developed electrode in the aid of SWCNHs exhibits fast response as well as outstanding potential stability, making it extreme promising for routine sensing application.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Bo-Yeong Kim, Han-Byeol Lee, Nae-Eung Lee〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Stretchable and disposable electrochemical biosensors as a new immunosensing platform are of great interest for the detection of biomarkers from body fluids including tears, interstitial fluids, sweat, or wound fluids. However, realization of such stretchable electrochemical biosensors has been limited by hurdles of obtaining electrochemical electrodes with high sensitivity, stretchability, and durability under mechanical deformation. Herein, a durable, stretchable, and disposable electrochemical biosensor fabricated by forming thermally evaporated Au working and counter electrodes and a stencil-printed Ag/AgCl reference electrode on a three-dimensional, micro-patterned stretchable substrate with curvilinearly connected bumps and valleys for efficient stress relief under stretching is reported. As an example of target biomolecule, tumor necrosis factor-α (TNF-α) cytokine in human serum ranging from 100 fM to 100 nM, a wound healing parameter, was detected using TNF-α antibody as a probe. The results show high stability of the sensing signal indicating minimal stretch-induced artefacts under a stretched state up to 30% and twisting. The device is also mechanically and electrochemically stable after cyclic stretching at 30% elongation. The device holds great potential for further integration into a body-attachable immunosensing platform, which is promising for the immunodetection of biomarkers in a wearable format.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A durable, stretchable, and disposable electrochemical immunosensor fabricated on a 3D micro-patterned elastomeric substrate on which distinctive 3D microstructures alleviated the stress applied to the sensor is demonstrated for the detection of immunoreactions. A stretchable electrochemical immunosensor with excellent capability of detecting specific protein biomarkers is promising for integration into body-attachable immunosensing platforms for diagnosis of various diseases from body fluids.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321646-ga1.jpg" width="288" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Mengxin Zhao, Haili Yu, Yi He〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present a dynamic multichannel colorimetric sensor array for highly effective discrimination of ten explosives, including 2,4-dinitrotoluene, picric acid, hexahydro-1,3,5-trinitro-1,3,5-triazine, 3-nitro-1,2,4-triazol-5-one, hexanitrohexaazaisowurtzitane, 2,6-diamino-3,5-dinitropyrazine-1-oxide, 1,1-diamino-2,2-dinitroethene, 4-nitrophenol, nitroguanidine, and 2,4-dinitrophenol. This sensor array is based on the fact that the reduction of indigo carmine by dithiothreitol generates semi-leucoindigo carmine and leucoindigo carmine at the different reaction time, resulting in abundantly available absorption peaks at 456 nm, 504 nm, 552 nm, 612 nm, 754 nm, and 906 nm as the sensing elements. Because of the presence of the supramolecular interactions and chemical reactions between explosives and indigo carmine, the distinct absorbance responses to each explosive are created as an analytical fingerprint to discriminate and identify ten explosives. The present colorimetric sensor array can efficiently discriminate individual explosive at a concentration of 1.5 μM and binary explosive mixtures. Additionally, this sensor array has the capability to identify individual explosive in real water samples.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Petr Sedlák, Petr Kuberský, Filip Mívalt〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The flow rate of analyte is a key parameter in the measurement system that influences response of gas sensors. The paper focuses on possibility of improved gas detection by modulation of analyte flow rate around amperometric sensors at equilibrium conditions by studying the direct current level and its fluctuations at selected concentration. To independently explore an impact of concentration and flow rate on spectral density of current fluctuations, all measurements were provided out under the same temperature, and each sample sensor was put to the same position at the test chamber to be under same fluidic condition. The experiments were carried out on the fully-printed amperometric NO〈sub〉2〈/sub〉 sensor based on a semi-planar three electrode topology. The aims of this experimental study are two-fold: firstly, to show that spectral density of current fluctuations significantly changes in the level and the shape as flow rate increases at constant concentration of detected gas; and secondly, to demonstrate that evaluation of these fluctuations and DC component can be used to compensate the negative effect of flow rate on sensor responses. The spectral density of current fluctuations develops as several mechanisms related to fluctuation phenomena become dominant with increasing flow rate. Thus, signal-to-noise ratio of current response on detected gas decreases as flow rate increases, while the ratio is almost invariant to gas concentration.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Muhammad Adil Riaz, Shengli Zhai, Li Wei, Zheng Zhou, Ziwen Yuan, Yanqing Wang, Qianwei Huang, Xiaozhou Liao, Yuan Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Detecting the trace amount of hydrogen peroxide (H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉) is essential for various industrial and biological applications. Platinum (Pt) based electrochemical H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 sensors have good sensing performances. Considering the high cost of Pt, it is desirable to develop high-performance H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 sensors with low Pt mass loadings. Here, we use a cathodic polarization treatment method to deposit ultralow mass loading of Pt nanoparticles on a high surface area porous carbon hybrid comprised of reduced graphene oxide nanosheets (rGO) and carbon nanotubes (CNTs). Under multiple cyclic voltammetry (CV) cycles in electrolytes without Pt precursors, Pt can be leached from a Pt mesh anode, and then migrate through electrolyte and anchor on the rGO-CNT hybrid as nanoparticles with narrow size distribution. Varying the number of CV cycles can precisely control the Pt mass loadings. The optimized Pt/rGO-CNT hybrid obtained after 3000 CV cycles contains about 4.8 wt.% Pt nanoparticles with the size of around 3–6 nm. The morphological and physicochemical properties of the synthesized Pt/rGO-CNT hybrids were characterized to understand their synthesis-structure-sensitivity relationship. The Pt/rGO-CNT hybrid show superior H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 sensing performances with a low detection limit of 1 μM, linear detection up to 15 mM, and high sensitivity of 2027 μA/ mM cm〈sup〉2〈/sup〉, which is the best among the recently reported Pt/carbon material based H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 sensors. It can also detect trace amount of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 in milk, and juice samples below the permitted residual level in food packaging, demonstrating its excellent practical application potential in food processing.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉High-performance H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 sensors created by depositing Pt nanoparticles on reduced graphene oxide-carbon nanotube hybrids without Pt precursors in the electrolyte.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321609-ga1.jpg" width="379" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Minxin Cui, Yiwei Zhuang, Gang Zou, Bing Zhu, Qijin Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, evanescent field initiated “click” polymerization on the surface of the waveguide is used to fabricate composite optical fiber taper probe for sensing. This improvement can effectively keep the polymerization within the scale of evanescent field on the surface of the fiber taper and prevent it in the precursor solution. Besides, for special sensing requirements, such as sensing target and sensitivity, this novel approach (photo-plating) is convenient to choose ingredients composed of the precursor solution in fabrication of a corresponding composite fiber taper probe. The photo-plating process usually completes within 30 s in specific precursor solution. As an example, a probe with a fluorescent polymer film composed of meso-tetrakis(4-allyloxyphenyl) porphyrin (TAOP) was made, which provides the binding sites for the nitro-based explosive molecules. The results indicate that the probe exhibits a good sensitivity and repeatability to trinitrotoluene (TNT), providing a fiber probe platform with miniaturization, real-time and remote monitoring for the detection of TNT vapor.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Gianluca Persichetti, Emanuela Viaggiu, Genni Testa, Roberta Congestri, Romeo Bernini〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉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.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Ali Özcan, Duygu Topçuoğulları, Ayça Atılır Özcan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a nanocomposite was prepared via reducing graphene oxide on fumed silica (FS) surface to develop a modified electrode for the determination of fenitrothion (FNT). Reduced graphene oxide (RGO) decorated FS (FS@RGO) was used to modify glassy carbon (GC) electrode. The modified electrode decreased the overpotential of FNT (80 mV) and increased prominently the reduction peak current of FNT (9 times). Scanning electron microscopy, energy dispersive X-ray, X-ray diffraction and Raman spectroscopy analyses revealed that the FS@RGO nanocomposite was successfully synthesized. The presence of FS on FS@RGO structure prevented the agglomeration and allowed the homogeneous distribution of the nanocomposite in water, which was a drawback for RGO. Moreover, the presence of FS brings additional functionality to FS@RGO nanocomposite, which increases the adsorption and electron transfer rate of FNT. The GC/FS@RGO electrode showed a linear response in a wide range of FNT concentration (0.005–1.0 μM) and a very low limit of detection (0.00019 μM). The performance of the GC/FS@RGO electrode was evaluated by performing recovery studies in river water, urine, raisin extract, tomato extract and orange extract. Acceptable recovery values between 92.3% and 112.2% were obtained during the analysis of FNT-spiked samples.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Harpreet Kaur, Narinder Singh, Navneet Kaur, Doo Ok Jang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a dipodal 2-(2-aminophenyl)benzimidazole scaffold appended to the lower rim of calix[4]arene at 1,3-alternate positions (〈strong〉L1〈/strong〉) was synthesized. Organic nanoparticles of receptor 〈strong〉L1〈/strong〉 (〈strong〉O1〈/strong〉) displayed remarkable selectivity and sensitivity for Fe〈sup〉3+〈/sup〉 ions via a turn-off fluorescence response in an aqueous medium. The 〈strong〉O1〈/strong〉·Fe〈sup〉3+〈/sup〉 complex was further studied for its binding ability toward biologically prevalent anions, and showed excellent selectivity for ADP in the nanomolar range, even in the presence of structurally similar nucleotides, with a blue shift and four-fold enhancement in the intensity of fluorescence emission. The determination of ADP is crucial because ADP plays significant roles in various biological reactions catalyzed by ATPases and kinases. ATP and ADP are also known to generate energy in cells via phosphate bond cleavage. The fluorescence quenching upon addition of Fe〈sup〉3+〈/sup〉 ions could be attributed to the conglomeration of the nano-aggregates, which either separated or further assembled when ADP was added to the ensemble. Consequently, the fluorescence of the ensemble could be recovered. The sensing system was also applied to the detection of ADP in spiked blood serum samples; the excellent recovery of up to 99.3% validated its practicality. The off-on sensing mode, simple fabrication process, and ease of synthetic methodology are some of the advantages for further applications. The sensor was also successfully applied to monitoring of the hydrolysis of ADP to AMP by apyrase, which indicated its potential application for ADP-pertinent biological activities.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322354-ga1.jpg" width="291" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Guanfeng Ji, Tianxiang Zheng, Xuechuan Gao, Zhiliang Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We herein design an innovative strategy for the detection of aspartic acid (Asp) based on a post-modification metal-organic framework Cu/Tb@Zn-MOF (〈strong〉3〈/strong〉), which is synthesized by successively encapsulating Tb〈sup〉3+〈/sup〉 and Cu〈sup〉2+〈/sup〉 ions into Zn-MOF (〈strong〉1〈/strong〉). Subsequently, the luminescence-quenched composite 〈strong〉3〈/strong〉 is developed as a fluorescence “turn-on” probe for Asp, demonstrating excellent selectivity and low detection limit (0.54 ppm). In addition, this On–Off–On pattern is further to construct an advanced analytical model based on IMPLICATION-type logic gate. More remarkable, the high selectivity and sensitivity for Asp are unparalleled among sensor type, with which lanthanide fluorescence is enhancing by MOFs.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉An on–off–on luminescent switch probe based on post-treatment metal-organic framework Cu/Tb@Zn-MOF was used for fluorescently “turn-on” detecting aspartic acid.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322330-ga1.jpg" width="149" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Sisi Hu, Tianlin Wang, Jingjing Zou, Zhe Zhou, Cuifen Lu, Junqi Nie, Chao Ma, Guichun Yang, Zuxing Chen, Yuexing Zhang, Qi Sun, Qiang Fei, Jun Ren, Feiyi Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tyrosinase (Tyr) is known as an important cancer-related biomarker, which shows significant over-expression in malignant tumor cells, such as melanoma. Developing highly sensitive and selective fluorescent probe for monitoring tyrosinase in living system is still challenging. In this project, we report a novel fluorescein-based highly chemoselective fluorescent probe (FT-3) capable of tracking tyrosinase 〈em〉in vitro〈/em〉 and 〈em〉in vivo〈/em〉 in turn-on model. FT-3 contains a 3-hydroxybenzyloxy unit as the tyrosinase recognition moiety, which precluded from interference of other competitive omnipresent ROS in living system and realized the highly chemoselective detection of tyrosinase. Furthermore, the probe worked in aqueous solution and showed more than 24-fold fluorescence enhancement in the presence of tyrosinase, which endows FT-3, an excellent signal to noisy ratio. In addition, we have successfully employed FT-3 to monitoring tyrosinase activity in different living cells and zebrafish models. We believe that our newly designed fluorescent probe will provide an alternative for tracking tyrosinase in complex living system.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Min Hyung Kim, Byungjin Jang, Wonkyung Kim, Wooyoung Lee〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report enhanced sensing properties of Pd-coated SnO〈sub〉2〈/sub〉 nanorod (NR) arrays for detecting H〈sub〉2〈/sub〉 gas in N〈sub〉2〈/sub〉 and dissolved in transformer oil. The Pd nanoparticles were coated on randomly ordered vertical SnO〈sub〉2〈/sub〉 NR arrays by the glancing angle deposition (GLAD) method, which utilizes an electron-beam evaporator and a DC magnetron sputtering system. The Pd-coated SnO〈sub〉2〈/sub〉 NR arrays exhibited high response (104 at 1% H〈sub〉2〈/sub〉) in N〈sub〉2〈/sub〉. Pd-coated SnO〈sub〉2〈/sub〉 NR arrays were immersed and in mineral oil that contains various concentrations of dissolved H〈sub〉2〈/sub〉 and the electrical response was measured. We found that the Pd-coated SnO〈sub〉2〈/sub〉 NR arrays showed superior response (〈em〉R〈/em〉 = ˜96), low detection limit (0.3 ppm), and fast response times (300 s). The Pd-coated SnO〈sub〉2〈/sub〉 NR arrays had a temperature coefficient of resistance (TCR) of 3.69 × 10-3 °C〈sup〉−1〈/sup〉 at various oil temperatures (20–80 °C), indicating good thermal stability at high temperatures. The sensing mechanism of the Pd-coated SnO〈sub〉2〈/sub〉 NR arrays was also demonstrated by using changes in the Schottky barrier height at the Pd/SnO〈sub〉2〈/sub〉 interface upon exposure to H〈sub〉2〈/sub〉.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Chao Zhang, Fengnian Zhao, Yongxin She, Sihui Hong, Xiaolin Cao, Lufei Zheng, Shanshan Wang, Tengfei Li, Mengqiang Wang, Maojun Jin, Fen Jin, Hua Shao, Jing Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel electrochemical sensor based on molecularly imprinted polymeric membrane as biomimetic recognition element was fabricated by electropolymerization of 〈em〉o〈/em〉-aminothiophenol (O-ATP) on gold nanoparticle/electrochemical reduction graphene oxide-modified screen-printed carbon electrode (AuNPs/ERGO-SPCE) for sensitive and selective detection of cyhexatin (CYT) pesticides. The sensor was constructed through self-assembly of O-ATP and CYT, following by the electropolymerization of O-ATP in the presence of CYT based on the hydrogen-bonding interaction. The obtained imprinted polymer film was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), fourier transforms infrared (FT-IR) spectra, cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimal condition, both the obtained imprinted sensors based on AuNPs/ERGO/SPCE presented satisfactory linearity with the certain concentrations of CYT and the limit of detection (LOD) can reach 0.20 ng mL〈sup〉−1〈/sup〉. The modification of ERGO and AuNPs could generate synergistic effect to increase the sensitivity of the MIP sensor. The developed imprinted sensors exhibited excellent long-term stability and repeatability. Furthermore, the established method was successfully applied to the determination of CYT in pear samples.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Na-Gyeong Kim, Ki-Won Lee〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a new sensing mechanism for dissolved-gas sensors, it has been reported that the reflectivity of bubbles growing on porous silicon film in water decreases in a nearly linear manner over time. In order to determine the cause of this peculiar phenomenon, we obtained a continuous stream of projection images of a bubble growing on a transparent glass substrate in different liquids (in this case beer and cola) with a high-speed camera. The time dependences of the bubble volume and the footprint area between the bubble and the substrate were also analyzed. As a result, it was found that the area of the ring-shaped black region in the projection image increases linearly in proportion to time, thereby decreasing the reflectivity linearly. It was also found that when the dissolved gas concentration in the liquid decreased during the growth of the bubble, the area of the ring-shaped black region increased nonlinearly with time rather than linearly.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Baolong Huo, Man Du, Ao Shen, Mengwen Li, Yaru Lai, Xue Bai, Aijun Gong, Leqiu Fang, Yunxu Yang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A highly selective and sensitive fluorescence “light-up” probe 〈strong〉PTH〈/strong〉 for ClO〈sup〉−〈/sup〉 has been developed, which is designed by a new strategy based on TEMPO-oxidation for the first time. 〈strong〉PTH〈/strong〉 exhibits excellent properties including quick response (within 2 min), lower detection limit (63.7 nM), good linearity (〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.9863) and specific selectivity. More importantly, its application of detection ClO- in real samples has also been achieved.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Xuan Ma, Fengliang Dong, Zhigang Zhang, Yong Su, Tan Xu, Zhaoxiang Jiang, Shangquan Wu, Qingchuan Zhang, Weiguo Chu, Xiaoping Wu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Chirality is an essential consideration in the field of life sciences and pharmaceutical industry because most biomolecules and pharmaceuticals are chiral, and optical rotation measurement is a simple and efficient means for identification, purity test and content detection of chiral materials. However, there are some drawbacks in existing methods, such as small measurement range, non-real-time performance, low measurement accuracy and resolution. This paper presents a novel system to implement optical rotation measurement, and pixelated polarization cameras and Stokes parameters are employed in the system. The polarization information of linearly polarized incident light can be recorded and extracted by a pixelated polarization camera and Stokes parameters respectively. Experiments demonstrate that the proposed system has the necessary advantages for optical rotation measurement, such as real time, wide range (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mo〉−〈/mo〉〈mn〉90〈/mn〉〈/mrow〉〈/math〉° to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mrow〉〈mo〉+〈/mo〉〈mn〉90〈/mn〉〈/mrow〉〈/math〉°), high accuracy (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.gif" overflow="scroll"〉〈mrow〉〈mn〉1〈/mn〉〈mo〉×〈/mo〉〈mn〉1〈/mn〉〈msup〉〈mn〉0〈/mn〉〈mrow〉〈mo〉−〈/mo〉〈mn〉4〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉°) and high resolution (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.gif" overflow="scroll"〉〈mrow〉〈mo〉±〈/mo〉〈mn〉6〈/mn〉〈mo〉×〈/mo〉〈mn〉1〈/mn〉〈msup〉〈mn〉0〈/mn〉〈mrow〉〈mo〉−〈/mo〉〈mn〉6〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉°). Thus, this measurement system has great practical prospects in the hospital clinical diagnosis, chemical research, sugar production and pharmaceutical industry.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Schematic representation of pixelated-polarization-camera-based polarimetry system for optical rotation sensing.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322172-ga1.jpg" width="390" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Longfei Song, Liping Yang, Zhou Wang, Di Liu, Linqu Luo, Xinxu Zhu, Yan Xi, Zaixing Yang, Ning Han, Fengyun Wang, Yunfa Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is a challenge to effectively detect the components of a gas mixture using metal oxide sensors which are easily fabricated and inexpensive. In this work, heterostructured SnO〈sub〉2〈/sub〉/MO〈sub〉x〈/sub〉 (i.e. M = Zn, Ga and W) nanotubes (NTs) and nanofibers (NFs) are synthesized via a one-step electrospinning technology and subsequent calcination for use in gas sensors. In specific, compared with pure SnO〈sub〉2〈/sub〉 NTs, SnO〈sub〉2〈/sub〉/ZnO NTs show an enhanced response to 100 ppm ethanol and acetone, while SnO〈sub〉2〈/sub〉/Ga〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 NTs show an obviously higher response to 100 ppm ethanol and SnO〈sub〉2〈/sub〉/WO〈sub〉3〈/sub〉 NFs show an optimal response to 100 ppm xylene. All these sensors are selective in the presence of typically interfering gases such as formaldehyde, benzene and toluene. As a proof-of-concept, sensor arrays constructed using these three sensors precisely detected the gas mixtures of ethanol, acetone and xylene by means of matrix manipulation, delivering a superior accuracy of 〈9% deviation for the gas concentration of 10 ppm and 20 ppm and 〈38% for the concentration of 5 ppm. These results show the possibility of improved selectivity in detecting gas mixtures using heterostructured gas-sensing materials for sensor arrays.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322160-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Mingrui Weng, Xue Yang, Yun Ni, Chenchen Xu, Hang Zhang, Jinjun Shao, Nannan Shi, Chengwu Zhang, Qiong Wu, Lin Li, Wei Huang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nitric oxide (NO), as one of important gaseous signaling molecule in human body, has been associated with a variety of physiologic processes. However, excessive production of NO has been profoundly implicated in the pathogenesis of neurodegenerative disorders in particular, Parkinson's disease (PD). Therefore, accurate and facile detection of NO is of great significance for investigating its functions in PD, and the subsequent diagnosis and/or treatment. Herein, we developed a deep-red fluorogenic probe (〈strong〉BT-NH〈/strong〉), with high sensitivity and good selectivity to detect NO, which was successfully used to visualize exogenous/endogenous NO level in living cells, and further applied to in vitro and in vivo PD models. Therefore, 〈strong〉BT-NH〈/strong〉 could be a potential biological fluorogenic tool to explore the roles of NO in PD.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321907-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Huanan Li, Haoqing Zhang, Ying Xu, Alzbeta Tureckova, Pavel Zahradník, Honglong Chang, Pavel Neuzil〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present a family of digital polymerase chain reaction (dPCR) chips made of silicon that are (9 × 9) mm〈sup〉2〈/sup〉 in size, have a unique layout design, and have between 26,448 and 1,656,000 reaction wells. The chip layout was split into six fields sized 4200 × 2785 μm〈sup〉2〈/sup〉 that contain reaction wells with a gap of a few μm separating the fields from each other. We also developed a universal fluorescence imaging method capable of processing images from those chips. It comprised automatic image acquisition, image stitching, alignment mark registration, rotation correction, determination of reaction wells’ positions, and result processing. The chip design, with fully automated image processing, provided a fast and reliable system for the absolute quantitative analysis of dPCR. Combined with ease-of-use, this family of dPCR chips offers a pathway to enable fast and affordable digital microfluidic diagnostic applications.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Guo Xiong Tham, Adrian C. Fisher, Richard D. Webster〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The determination of pH using the conventional potentiometric glass electrode is widely practised in various fields ranging from academic to industrial environments. Recent research has focused on using various redox active organic and inorganic compounds as a basis of developing novel and miniaturized voltammetric pH sensors. This report describes the electrochemistry of such a sensor that is aimed to be disposable and based on a glassy carbon (GC) electrode drop cast with redox active vitamins. Voltammetric studies in deoxygenated buffered media revealed riboflavin (VB〈sub〉2〈/sub〉) and a vitamin E derivative (VEa) to be suitable as pH-dependent and independent electroactive compounds, respectively. Solid-state square-wave voltammograms of VB〈sub〉2〈/sub〉 and VEa that were concurrently drop cast on a GC electrode in various pH deoxygenated and oxygenated buffered media yielded Nernstian responses of –54.3 and –53.4 mV/ΔpH respectively, with the linear plot of the potential difference of VB〈sub〉2〈/sub〉 against VEa as a function of pH. Poor Nernstian responses were obtained in deoxygenated and oxygenated non-buffered media when the pH was above approximately 4. However, with the addition of a very low concentration of an acidic buffer into the reference solution, Nernstian responses of –50.0 and –50.9 mV/ΔpH were successfully achieved in deoxygenated and oxygenated weakly-buffered media, respectively. Furthermore, a strong correlation of voltammetric versus potentiometric pH highlights the suitability of the redox active vitamin compounds as a basis for a miniaturized voltammetric pH sensor.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Joanna Gordon Casey, Ashley Collier-Oxandale, Michael Hannigan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We tested the performance of regression via inverse linear models (LMs), direct LMs, and artificial neural networks (ANNs) towards field calibration of low-cost gas sensors in an area influenced by oil and gas production activities to quantify O〈sub〉3〈/sub〉, CO, CO〈sub〉2〈/sub〉, and CH〈sub〉4〈/sub〉 in ambient air. Sensors were co-located with reference measurements in Greeley, Colorado. We selected a three-month period of data in the spring of 2017 to conduct our analysis. Approximately two months of measurements bookending the middle test month were used for model training. We found that ANNs generally outperformed LMs and that direct LMs generally outperformed inverted LMs. An analysis of model residuals during the test period revealed that ANNs were better able to mitigate curvature and linear trends relative to direct LMs with the same set of inputs.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321683-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Shi Gang Liu, Lei Han, Na Li, Yu Zhu Fan, Yu Zhu Yang, Nian Bing Li, Hong Qun Luo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The development of ratiometric fluorescent strategy is very significant and challenging in bioanalysis. Herein, graphitic carbon nitride (g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉) nanosheets and cobalt oxyhydroxide (CoOOH) nanoflakes are exploited for ratiometric fluorescence assay of alkaline phosphatase (ALP) activity. In the g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/CoOOH nanohybrid, g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 nanosheets serve as a signal unit and the CoOOH nanoflakes function as a recognition element, and initially, the fluorescence of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 is quenched by the CoOOH nanoflakes. In the absence of target, the CoOOH nanoflakes of the nanohybrid system are able to oxidize o-phenylenediamine (OPD), and the resultant oxidation product (OxOPD) quenches the blue emission of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 and meanwhile emits orange fluorescence which acts as another signal element. However, an efficient redox reaction between ascorbic acid (AA) and CoOOH can cause decomposition of the CoOOH nanoflakes, and additionally, ALP can catalytically hydrolyze L-ascorbic acid-2-phosphate (AAP) to generate AA. Thus, in the presence of target, the CoOOH nanoflakes are destroyed by AA preferentially and the OPD is rarely oxidized to OxOPD, accompanied with strong blue emission of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 and weak orange fluorescence from OxOPD. Target-dependent dual-signal change made the ratiometric assay possible, and also AA-induced signal variation was investigated and attributed to the stronger reducing capacity of AA than OPD. The ratiometric sensing platform for ALP activity assay provides a new perspective for the applications of two-dimensional nanomaterials to develop novel and sensitive biosensors.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321713-ga1.jpg" width="360" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Alina Lyuleeva, Tobias Helbich, Marco Bobinger, Bernhard Rieger, Markus Becherer, Paolo Lugli, Almudena Rivadeneyra〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The use of completely oxidized two-dimensional (2D) silicon nanosheets (SiNSs) represents a novel approach for the application of 2D silicon-based materials in the nanoelectronics field. Densely stacked and highly porous oxidized SiNSs (OSiNSs) act as a sensitive layer for humidity detection. Due to the oxidation-caused porosity of the SiNSs and the possibility functionalize the 2D surface with hydrophilic groups, this hybrid material exhibits an extremely good sensitivity towards relative humidity (RH). In this work, precise tuning of the SiNSs’ sensing properties by their functionalization is demonstrated. In particular, the modification with methacrylic acid (MAA) groups, leading to SiNS-MAA, and the subsequent deposition on interdigitated electrodes double the capacitance value in the range of 20–85%RH. These values were achieved after the full oxidation of SiNS-MAA in ambient conditions. The mentioned changes in capacitance are extremely high compared to the response of the so far known common polymer humidity sensors. Contrary to that, this response is neutralized when the SiNSs are functionalized with 〈em〉tert〈/em〉-butyl acrylic acid (〈sup〉t〈/sup〉BMA), a rather hydrophobic functional group. The fabricated devices show, how the specific functionalization of SiNSs serves as a reliable tool to provide sensitivity towards RH. Similar approach, based on tuning the functionality, can be applied to achieve 〈em〉e.g.,〈/em〉 sensor array selectivity. For this purpose, the functional groups on the surface of the nanomaterial can be further modified. Additional molecules with sensitivities towards various surrounding conditions could be attached. Furthermore, these functional molecules can be used for subsequent (bio)molecule immobilization, which can serve as sensitive molecular groups towards surrounding substrates and gases. However, one of the main challenges in sensor technology is to find a highly selective solution: a sensor system capable to differentiate among different vapor species. The described strategy can serve as an access towards new and promising solutions, which can help to face this issue in modern nanomaterials-based technology.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Yu Cao, Luona Wang, Chao Shen, Chengyin Wang, Xiaoya Hu, Guoxiu Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An electrochemical sensor based on hierarchically Cu-BTC MOF material for non-electroactive glyphosate detection has been firstly constructed in this report. By using Cu-BTC frameworks as a detection matrix, the large specific surface area of the material can increase the electrode reaction site and further improve the detection performance. The electrochemical behavior of Cu-BTC frameworks for glyphosate detection was evaluated by cyclic voltammetry (CV). Under optimum conditions, differential pulse stripping voltammetry (DPV) is employed to detect glyphosate. The results show that the fabricated sensor displays ultralow detection limit (1.4 × 10〈sup〉−13〈/sup〉 mol L〈sup〉-1〈/sup〉) and wide detection range (1.0 × 10〈sup〉-12〈/sup〉 to 1.0 × 10〈sup〉-9〈/sup〉 mol L〈sup〉-1〈/sup〉 and 1.0 × 10〈sup〉-9〈/sup〉 to 1.0 × 10〈sup〉-5〈/sup〉 mol L〈sup〉-1〈/sup〉). Besides, this sensor possesses acceptable reproducibility and stability, as well as good selectivity against the major metabolite of glyphosate aminomethylphosphonic acid (AMPA) and other interference. Furthermore, this electrochemical sensor can also be applied to the detection of glyphosate in soybean. It is worth mentioning that this effectively Cu-BTC based sensor has great potential application in favorable and selective detection of organophosphorus pesticides in actual samples.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Jounghyun Yoo, UnJin Ryu, Woosung Kwon, Kyung Min Choi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Among the heavy metals commonly found in wastewater, Cr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉〈sup〉2−〈/sup〉 is considered the most hazardous due to its high toxicity, carcinogenicity, and mutagenicity. Nevertheless, detection and removal of Cr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉〈sup〉2−〈/sup〉 remains a serious challenge as it competes with other metal cations and anions in wastewater. Herein, self-calibration of the emission intensities at two different wavelengths was introduced to microporous media to facilitate the ratiometric detection and simultaneous removal of Cr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉〈sup〉2−〈/sup〉 in the presence of excess interfering ions. Specifically, a multi-dye (7-amino-4-methylcoumarin and resorufin) containing metal-organic framework-801 (Dyes⊂MOF-801) was developed and tested for the detection and removal of Cr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉〈sup〉2−〈/sup〉 from wastewater. Dyes⊂MOF-801 exhibited accurate detection of Cr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉〈sup〉2−〈/sup〉 with high sensitivity in the presence of a 260-fold excess of potentially interfering ions. Its maximum removal capacity was 83 mg/g and was achieved within 3 min, even in the presence of excess metal ions and 10-fold excess concentrations of anions. In addition, the residual concentration of Cr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉〈sup〉2−〈/sup〉 was simultaneously checked using ratiometric detection of Dyes⊂MOF-801, so that the removal of Cr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉〈sup〉2−〈/sup〉 could be immediately confirmed.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Tae-Il Kim, Dami Kim, Jean Bouffard, Youngmi Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report the design of an enhanced PeT-based fluorogenic phosgene probe 〈strong〉1-CN〈/strong〉 comprising a BODIPY fluorescence reporter, and a catechol quencher at the 〈em〉meso〈/em〉-position acting as the phosgene reaction site. The fluorescent catechol-derived probe 〈strong〉1-CN〈/strong〉 specifically reacts with phosgene to result in a cyclic carbonate ester. The fast (〈 3 s) reaction suppresses a reductive PeT quenching process, leading to a fluorescence turn-on signal (〈em〉F/F〈sub〉0〈/sub〉〈/em〉 up to 〈em〉ca〈/em〉. 1300). The high sensitivity (LOD = 24 pM) of the probe is achieved by the precise adjustment of the energy levels of the frontier orbitals involved in the PeT.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉We report the design of an enhanced PeT-based fluorogenic phosgene probe 〈strong〉1-CN〈/strong〉 comprising a BODIPY fluorescence reporter, and a catechol quencher at the 〈em〉meso〈/em〉-position acting as the phosgene reaction site. The fluorescent catechol-derived probe 〈strong〉1-CN〈/strong〉 specifically reacts with phosgene to result in a cyclic carbonate ester. The fast (〈 3 s) reaction suppresses a reductive PeT quenching process, leading to a fluorescence turn-on signal (〈em〉F/F〈sub〉0〈/sub〉〈/em〉 up to 〈em〉ca〈/em〉. 1300). The high sensitivity (LOD = 24 pM) of the probe is achieved by the precise adjustment of the energy levels of the frontier orbitals involved in the PeT.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321361-ga1.jpg" width="351" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Peng Chen, Chen Chen, Yuhong Liu, Wei Du, Xiaojun Feng, Bi-Feng Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Paper-based diagnostics have been successfully explored for nucleic acid detection. However, multi-step integration (such as nucleic acid extraction, washing, amplification and detection) into a single paper chip remains a huge challenge. Here, a simple, inexpensive, and fully integrated paper chip was demonstrated for detecting gene mutations, which could potentially play a guiding role in individualized treatments to improve the survival rate of lung cancer patients. To simplify the pipetting and manipulation of samples, we incorporated DNA extraction, purification, amplification and detection into a single chip. Further integration of lateral flow test allowed the detection of gene mutation by naked eye. The gene mutation in the epidermal growth factor receptor (EGFR〈sub〉L858R〈/sub〉) in lung adenocarcinoma cells was successfully detected with high specificity and sensitivity within 90 min by the proposed fully integrated chip. This low cost, disposable and user-friendly chip provided a new and rapid molecular diagnostic platform, especially suitable for molecular diagnostics in resource-limited areas.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Dandan Fang, Xiangqin Zheng, Huan Yi, Hong Dai, Zhensheng Hong, Yiru Peng, Yanyu Lin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A highly sensitive electrochemiluminescence (ECL) immunosensor was fabricated for the quantitative analysis of deoxynivalenol (DON) based on an effective all-in-one bioprobe that composed of TiO〈sub〉2〈/sub〉-B with Fluoro-coumarin silicon phthalocyanine (F-couSiPc) and luminol. Herein, TiO〈sub〉2〈/sub〉-B with large specific area was served as a favorable carrier, greatly increased the loading of enhancer F-couSiPc and luminophore luminol, resulting in the tremendous enhancement of ECL signal. Specifically, F-couSiPc as coreaction accelerator could facilitate the decomposition of dissolved O〈sub〉2〈/sub〉 to generate substantial reactive oxygen species (ROS) to participate in the ECL reaction of luminol. Additionally, the prepared PEDOT/HA@mp MnO〈sub〉2〈/sub〉 was employed as the sensing platform of biosensor, which can not only capture substantial antibody to improve the sensitivity, but also could expedite the electronic transmission rate to make the ECL intensity further amplified. Ultimately, the proposed immunosensor presented favorable performance for the determination of DON, such as high sensitivity, good stability, wide liner range (from 1.0*10〈sup〉−6〈/sup〉 ng/mL to 10 ng/mL) and a low detection limit of 3.3*10〈sup〉-7〈/sup〉 ng/mL.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Charlotte S. Stravers, Elmar L. Gool, Ton G. van Leeuwen, Maurice C.G. Aalders, Annemieke van Dam〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Body fluid identification is a key component in forensic casework, providing important information for the reconstruction of criminal events. Body fluid identification in combination with DNA analysis allows the linking of individuals to criminal acts and can therefore be of great importance in determining the outcome of criminal court cases. However, none of the current body fluid identification methods meet all forensic requirements, such as a high sensitivity, a high specificity and the ability to analyse multiple body fluids in a single run. In this pilot-study, we explore, for the first time, surface plasmon resonance imaging (SPRi) with antibody-based detection to serve as a novel multiplex body fluid identification assay for blood, semen, saliva, urine and sweat using minimal sample preparation. A training set consisting of ten donors per body fluid was analysed to determine whether body fluid specific response signals could be obtained. Principal component analysis (PCA) was performed as a statistical tool to cluster the body fluid samples by response signal pattern reduction and to uncover the sources of variation between the body fluids. Four principal components allowed complete clustering of all body fluid types. Blind testing of body fluid samples revealed that five out of eight unknown samples could correctly be clustered to their corresponding group, three out of eight samples were identified as inconclusive. Although optimization of the current SPRi method is required for use in the forensic field, this pilot-study demonstrates the feasibility of SPRi to differentiate five forensically relevant body fluids.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Shih-Rong Su, Yuan-Yu Chen, Kuan-Ying Li, Yu-Cheng Fang, Chih-Hsien Wang, Chiou-Ying Yang, Lai-Kwan Chau, Shau-Chun Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Gas ions can be ejected at the tip of a corona needle to form an ionic wind. When the corona needle is close to one hemispherical droplet sitting on flat glass slide, the ionic wind wiping across the liquid surface can induce micro-centrifugal vortex inside the droplet to drag suspended particles to the droplet bottom to trap at the stagnant point. Besides using this electrohydrodynamically generated ionic wind, the droplet evaporation can be enhanced because the eddy air streams around the droplet substantially increase the moisture removal rate. The liquid evaporation can induce internal fluid circulation to assemble particles on the surface. When the surface tension is significantly altered to stretch the contact line, the droplet is flatten as a liquid film to accelerate drying processes. The droplet is finally dried down. The trapped particles then become solid deposits and concentrate on the glass slide.〈/p〉 〈p〉This paper describes that the ionic wind flows were applied to evaporate a droplet of 10 μL as a liquid film within 15 min to further concentrate vortex-trapped 〈em〉Salmonella〈/em〉 at the level of 1000 colony forming units (CFU) per mL (or lower), when the bacteria were bound with antibody-conjugated Raman tags made of silica-coated gold nanoparticle aggregates containing reporter molecules. Using this evaporation device, the concentration effects was concluded to be 300-fold higher than using the previous ionic wind-driven micro-centrifugal device. Using 30 μL sample volume, single CFU of Raman tag-bound 〈em〉Salmonella〈/em〉 was detected, which was equivalent to about 30 CFU mL〈sup〉−1〈/sup〉.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Bacteria bound with antibody-functionalized SERS micro-tags in sample droplet are concentrated with corona-induced micro-centrifugal flows while the droplet is electrohydrodynamically evaporated using ionic wind at the same time to dry down within 20 min. Concentrated bacteria in dried spot are recognized and quantified using Raman microscope based on SERS signals from the tags.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321671-ga1.jpg" width="387" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Shiyun Zhang, Chenbo Yin, Liu Yang, Zili Zhang, Zhongjun Han〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Multilayer mesoporous pure and Pd-doped SnO〈sub〉2〈/sub〉 thin films had been successfully synthesized through an evaporation induced self-assembly (EISA) method using Pluronic F127 as template and deposited by an improved spin-coating method. The crystalline structure and micro morphology of the prepared materials were analyzed. The specific surface area and average pore size of mesoporous SnO〈sub〉2〈/sub〉 were 90.61 m〈sup〉2〈/sup〉/g and 4.89 nm, respectively. The average crystallite size was about 6 nm for mesoporous SnO〈sub〉2〈/sub〉. The H〈sub〉2〈/sub〉 sensing properties were investigated to different H〈sub〉2〈/sub〉 concentrations and at different temperatures. The response magnitude of the five-layer pure mesoporous SnO〈sub〉2〈/sub〉 thin film to 1000 ppm H〈sub〉2〈/sub〉 at 175 °C was 237.85. This amount was approximately 4.11 times that of single layer sample. The correlation of the response magnitude and H〈sub〉2〈/sub〉 concentration of the five-layer pure mesoporous SnO〈sub〉2〈/sub〉 thin film was more linear compared to the five-layer Pd-doped mesoporous SnO〈sub〉2〈/sub〉 thin film, which had the highest response magnitude of 774.49–1000 ppm and 1115.39–2000 ppm H〈sub〉2〈/sub〉 at 175 °C. The response and recovery behavior was discussed and the mechanism of the outstanding H〈sub〉2〈/sub〉 sensing performance was explained.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Satyendra Mourya, Arvind Kumar, Jyoti Jaiswal, Gaurav Malik, Brijesh Kumar, Ramesh Chandra〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Present work demonstrates the hydrogen gas (H〈sub〉2〈/sub〉) sensing characteristics of palladium-platinum (Pd-Pt) functionalized silicon carbide (SiC) thin film grown on porous silicon (PSi) substrate for high temperature applications. Nano-crystalline SiC thin film was deposited by RF magnetron sputtering on anodized PSi substrate. The loading of discrete ultra-thin Pd-Pt bimetallic catalytic layer was carefully controlled by varying the sputtering parameters. The proposed device architecture (Pd-Pt/SiC/PSi) revealed significant advantages, such as stable high sensing response, large tunable detection range (5–500 ppm), fast response/recovery time, excellent reproducibility, high selectivity, wide operating temperature regime (25–500 °C) and good durability. The observed high response may be ascribed to the combined effect of enhanced catalytic activity of bimetallic Pd-Pt layer and increased surface area of the proposed sensor.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321610-ga1.jpg" width="381" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Shicai Xu, Chao Zhang, Shouzhen Jiang, Guodong Hu, Xiaoyue Li, Yan Zou, Hanping Liu, Jun Li, Zhenhua Li, Xiaoxin Wang, Mingzhen Li, Jihua Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As the major energy molecule of cells, adenosine triphosphate (ATP) regulates various biological processes and has been found to be closely related to many diseases. Therefore, ATP detection in trace amounts is very useful for understanding various biological processes, studying cellular events such as proliferation and apoptosis, and estimating contaminated degree of food and medical instrument. To date, the trace sensing ATP at picomolar level in biological systems is still a major challenge. Because of unique electrical and structural properties, graphene has attracted much attention in biosensing applications. Here, a sensitive and selective graphene foam field-effect transistor (GF-FET) biosensor for ATP detection is demonstrated. The lowest detection limit of the biosensors for analyzing ATP is down to 0.5 pM, which is one or several orders lower than the reported results. Moreover, the GF-FET biosensor show a good linear current response to ATP concentrations in a broad range from 0.5 pM to 50 μM. The GF-FET sensor surface can be regenerated for many times and used for up to weeks without significant loss of functionality. Based on this sensing platform, label-free measurements of ATP concentrations in human serum as well as in cell lysate are demonstrated. The work may provide a novel platform to study ATP release and energy-regulated biological processes, suggesting a promising future for biosensing applications.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Byung Ju Yun, Ji Eon Kwon, Kangwon Lee, Won-Gun Koh〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A new metal-enhanced fluorescence (MEF)-based biosensor platform was prepared on fibrous substrates. First, polycaprolactone (PCL) fibers were obtained via electrospinning process. PCL fibers were decorated with photoreduced silver nanoparticles followed by silica coating, generating silver-decorated PCL fibers with a silica layer (Ag@SiO〈sub〉2〈/sub〉-PCL). The silica layer acted as a spacer between the silver nanoparticles and the fluorescent molecules to optimize the MEF effect. The MEF was obtained from the silver-decorated PCL fibers, the extent of which could be controlled by the thickness of the silica layer. The fibrous structure of Ag@SiO〈sub〉2〈/sub〉-PCL had higher protein loading capacity than conventional two-dimensional glass slides due to its large surface area, while the presence of silica-coated silver nanoparticles resulted in higher fluorescence intensity than silica-coated PCL fibers (SiO〈sub〉2〈/sub〉-PCL) without silver nanoparticles via the MEF effect. Both features of Ag@SiO〈sub〉2〈/sub〉-PCL were combined to produce combined effects in improving the performance of fluorescence-based biosensing. According to immunobinding assays between fluorescently labeled anti-IgG and IgG immobilized onto different substrates, Ag@SiO〈sub〉2〈/sub〉-PCL had much better sensing performance in terms of sensitivity and detection limit than glass slides and SiO〈sub〉2〈/sub〉-PCL due to the combined effects of a large surface area and the MEF effect.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322159-ga1.jpg" width="251" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Zhihui Yu, Yanan Luan, Haiyu Li, Wan Wang, Xiayan Wang, Qing Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A disposable and sensitive electrochemical aptasensor was developed based on a single-stranded DNA (ssDNA)–methylene blue (MB) complex for the determination of bisphenol A (BPA). BPA-specific aptamer, a ssDNA with hairpin structure, was immobilized on a low-cost plastic electrode and acted as both the bio-recognition element and the signal-amplification platform. MB was then intercalated into the aptamer and acted as the signaling probe. The intercalated MB was liberated upon interaction with BPA due to DNA conformational change, thereby resulting in the reduction of electrochemical response. The proposed sensors in the intermediate and final stages were carefully characterized. Under optimal conditions, a good linear relationship was presented with the logarithm of BPA concentrations in the range of 0.001–100 μg/L, and a detection limit of 0.4 ng/L was obtained. This proposed sensor was applied to detect BPA in real samples and achieved satisfying results.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): Keyuan Liu, Ganhong Du, Long Ye, Liming Jiang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Histidine is one of the essential amino acids in the human body, and the variation of its concentration 〈em〉in vivo〈/em〉 has shown it to align with some liver and kidney diseases. In this work, a series of novel poly(2-oxazoline) derivatives bearing chiral pyrrolidine–triazole moieties in the side chain were designed and synthesized to serve as chemical sensors for histidine. The results demonstrated that the homopolymer 〈strong〉HPOx2〈/strong〉 is capable of selectively binding optically active histidine through nitrogen/Cu〈sup〉2+〈/sup〉 coordination to form complexes exhibiting induced circular dichroism (ICD) signals with signs related to the absolute configuration of the guest compound. Interestingly, the micelle-type nanoparticles assembled from the corresponding amphiphilic copolymer (〈strong〉CPOx2〈/strong〉) gave a much stronger CD response, with an intensity five times that of its small molecule- or homopolymer counterparts. The proposed method, based on the chiroptical probe, allows for enantioselective detection of histidine in aqueous media, showing potential application in the field of biomedical assay and chiral drug synthesis.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Konstantinos Petropoulos, Sergio F. Bodini, Laura Fabiani, Laura Micheli, Alessandro Porchetta, Silvia Piermarini, Giulia Volpe, Fabio Massimo Pasquazzi, Luca Sanfilippo, Pompeo Moscetta, Salvatore Chiavarini, Giuseppe Palleschi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The increasing demand by citizens and environmental organization for the protection, preservation, and possible restoration of the marine environment has made seawater protection one of the urgent priorities of the European Union. In this contest, extensive monitoring and surveillance are required to correctly assess the current status of marine environment, paying attention not only to traditional chemical parameters, but also to the so-called “emerging pollutants”. Among these, marine biotoxins represent a serious hazard, because they can accumulate in fish and mussels and enter the food chain. The detection of marine toxins released by algae has mostly been directed on the analysis of fish/shellfish homogenate rather than seawater samples. To fill this gap, in this work, we propose the re-modeling of ELISA kits to set-up non-automated direct competitive ELIMC (Enzyme-Linked Immuno-Magnetic Colorimetric) assays for the detection of Domoic Acid (DA), Okadaic Acid (OA) and Saxitoxin (STX) in seawater.〈/p〉 〈p〉For each toxin, linear working range, sensitivity and detection limit (0.03, 0.05, 0.01 ng/mL for DA, OA and STX, respectively) of the ELIMC assays were calculated. After evaluation of seawater matrix effect and recovery study, ELIMC assays were integrated within a novel automated networked system (ASMAT - Analytical System for Marine Algal Toxins) based on the micro Loop Flow Reactor (μLFR) technology, suitable for on-line monitoring of marine toxins. Once established the best operational conditions, ASMAT was calibrated towards DA, OA and STX verifying its capability to detect sub-ppb levels of the target toxins. Analysis of DA, OA and STX in real samples of marine water, sampled in Alonnisos (Greece) were carried out in laboratory using ELIMC assays, ASMAT and ELISA Kits, for a comparative evaluation. Finally, on-line suitability of ASMAT as an early warning alarm system was demonstrated by a field installation within a floating platform in the port of La Spezia (Italy).〈/p〉 〈/div〉

Description: 〈p〉Publication date: 1 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 284〈/p〉 〈p〉Author(s): M.K. Filippidou, M. Chatzichristidi, S. Chatzandroulis〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A versatile, two-step, lift-off method, for the fabrication of flexible capacitive chemical sensors based on interdigitated electrodes (IDEs) is presented. A Polyimide (PI) foil whose one side is coated with a thin Aluminum (Al) film is used as the sensor substrate. The IDEs are then formed on the Al film using conventional semiconductor processes. Precise patterning of the sensor sensing layer, on the surface of the Al IDEs, is achieved using a two-step lift-off process which involves a first lift-off during which a Polyvinyl alcohol (PVA) film is spin-coated and patterned, followed by the deposition or spin coating of the sensing layer and a second lift-off to pattern it on the IDEs area and form the final sensor. The process allows for upscaling when a single sensing layer is deposited and patterned in batch over the whole wafer or for the easy fabrication of chemical sensor arrays when depositing and precisely patterning different sensing layers on an array of IDEs. Showcasing the first approach, PHITA copolymer (a methacrylate tertrapolymer) is deposited and patterned over sensors with varying electrode gaps in order to fabricate simple humidity sensors, while in a following experiment, Poly(2-hydroxyethyl methacrylate) (PHEMA), Epoxy novolac resin (EPN), Poly(methyl methacrylate) (PMMA) and Poly(hydroxy styrene) PHS are patterned on the IDEs in order to form a sensor array. The different sensor configurations realized are evaluated when exposed to water, methanol and ethanol vapors with PHS sensor exhibiting a capacitance change of 44 fF (sensitivity: 1.87 fF / %RH), 7.4 fF and 4.6 fF at 10,000 ppm respectively.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322147-ga1.jpg" width="221" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Xinwei Wei, Chenlei Gu, Hongbo Li, Yuxiang Pan, Bin Zhang, Liujing Zhuang, Hao Wan, Ning Hu, Ping Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cancer significantly threatens human life, and the chemotherapy drugs are developed and widely used in the cancer treatment. However, the side effects of drugs on heart cause other serious problems. In this study, a dual functional cell-based biosensor integrating interdigitated electrodes (IDEs, monitoring cell viability) and microelectrodes (monitoring electrophysiology) is developed to comprehensively evaluate the efficacy and cardiotoxicity of anticancer drugs. Hela cells and cardiomyocytes of neonatal rats were cultured on this cell-based biosensor. Taxol (TAX) and vinblastine (VBL) were utilized to verify the performance of this platform. The efficacy of TAX and VBL were verified by comparing the results of traditional method and this method. As for cardiotoxicity, TAX showed little effect on cell viability, and slightly influenced the electrophysiological activity of cardiomyocytes at the range of 50–800 nM (with the sensitivity of -13.48%/lg TAX (nM) in field potential amplitude (FPA)) and 7.12%/lg TAX (nM) in firing rate (FR)). By contrast, VBL presented a relatively strong effect on both cell viability and electrophysiological activity of cardiomyocytes, which show a dose-dependent manner within a certain concentration range (with the sensitivity of -41.86%/lg VBL (nM) in FPA and -30.45%/lg VBL (nM) in FR). Owing to its simultaneously monitoring cell viability and electrophysiological activity of cells in a real-time and dynamic way, the dual functional cell-based biosensors will be a utility platform to evaluate the efficacy and cardiotoxicity of candidate compounds in new drug development.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518322056-ga1.jpg" width="266" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Paramasivam Balasubramanian, T.S.T. Balamurugan, Shen-Ming Chen, Tse-Wei Chen, Pei-Hung Lin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉At present, B/N co-doped mesoporous carbon (BNDC) have been synthesized in one-step and employed for high sensitive electrochemical detection of Isoniazid (INZ). The synthetic procedure was simple and produced homogenous doping of heteroatoms with high elemental purity and mesoporous surface. Further, the surface and physiochemical properties of synthesized BNDC was analysis by Nitrogen (N〈sub〉2〈/sub〉) adsorption-desorption analysis, and spectroscopic studies. A high sensitive amperometric sensor of BNDC film modified electrode, towards INZ, delivered superior analytical performance with a broad dynamic range 0.02–1783 μM and detection limit of 1.5 nM. Excellency of electrochemical sensor can be attributed to the large surface area, low pore size, abundant active sites, and enhanced electrical conductivity of synthesized BNDC electrocatalyst. Furthermore, the excellent chemical stability of BNDC advocates the long-term stability and reproducibility of the fabricated electrochemical assay. The practical applicability of the proposed sensor was assessed by detection of INZ in physiological fluids.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321397-ga1.jpg" width="404" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Diandian Deng, Hong Yang, Chang Liu, Kang Zhao, Jianguo Li, Anping Deng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the last years, surface-enhanced Raman scattering based immunochromatographic assay (SERS-ICA) has been getting great attention and been applied for the detection of different target analytes. In this study, a novel SERS-ICA using Ag〈sup〉MBA〈/sup〉@SiO〈sub〉2〈/sub〉-Ab as an immunoprobe has been developed for rapid, quantitative and ultrasensitive detection of a pharmaceutical diclofenac (DCF) residue in water samples. Ag, Ag@SiO〈sub〉2〈/sub〉 and Ag〈sup〉MBA〈/sup〉@SiO〈sub〉2〈/sub〉 nanoparticles (NPs) were synthesized and characterized. The immunoprobe was prepared by sandwiching the Raman reporter mercaptobenzoic acid (MBA) between the core-shell layers and immobilizing the monoclonal antibody (mAb) against DCF on the surface of the Ag@SiO〈sub〉2〈/sub〉 NPs. Under optimal conditions, the sensitivity and limit of detection (LOD) of the SERS-ICA for DCF were found to be 9 pg mL〈sup〉−1〈/sup〉 and 0.07 pg mL〈sup〉-1〈/sup〉, respectively. The detection of the SERS-ICA for DCF was completed within 15 min. Ag〈sup〉MBA〈/sup〉@SiO〈sub〉2〈/sub〉-Ab was stable within four months without significant loss of SERS intensity. The key to success of the SERS-ICA was the employment of the Ag@SiO〈sub〉2〈/sub〉 NPs as the SERS substrate, which possessed gorgeous SERS enhancement capability, predominant biocompatibility and excellent stability. This SERS-ICA is potential as an ultrasensitive analytical method in point-of-care testing, clinical diagnosis, food inspecting and environmental monitoring.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321956-ga1.jpg" width="230" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Jiuyang Zhang, Yuhua Zhen, Haoyue Xue, Xiaoxin Gao, Wenxin Wang, Yingda Li, Tasawar Hayat, Njud S. Alharbi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An urchin-like nano-composite of SnO〈sub〉2〈/sub〉/NaNbO〈sub〉3〈/sub〉 was fabricated by the hydrothermal method and the influence of the Sn/Nb ratio in the samples on their humidity-sensing properties was investigated. The phases and morphologies of these composites and their elemental distributions were analyzed by X-ray diffraction scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The sensor based on the optimum Sn/Nb ratio of 1:0.4 exhibited remarkable humidity-sensing properties, including a good response (〈em〉S〈/em〉 = 4823.8) that was 8.72 times higher than that of the pure SnO〈sub〉2〈/sub〉 sensor (〈em〉S〈/em〉 = 553.01). The composites showed rapid response and recovery times (3/9 s), as well as good stability, linearity, and excellent selectivity. The fabrication and humidity-sensing mechanisms were systematically analyzed using analog computations and Nyquist diagrams, respectively. Compared with pure NaNbO〈sub〉3〈/sub〉 and SnO〈sub〉2〈/sub〉 sensors, our easily prepared SnO〈sub〉2〈/sub〉/NaNbO〈sub〉3〈/sub〉 sensor demonstrates good sensing properties and holds great promise for use in humidity-sensing applications.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Zhuangzhi Sun, Lu Yang, Dan Zhang, Wenlong Song〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A flexible nano-biocomposite artificial muscle based on a mesoporous renewable cellulose/ionic liquid (IL-Cel) electrolyte membrane with high porosity of 91.31% was developed in this paper. The IL-Cel electrolyte membrane, fabricated by a solution-phase separation process, exhibited absolute advantages in flexibility and ion transfer efficiency, so IL-Cel regenerated actuators exhibited significant enhancement in the deflection displacement and force, which were 4 and 2 times greater than traditional DMAC/Li-dissolved cellulose (Dm-Cel)-based actuators. Good flexibility (from the tensile test) and low surface resistance (within 100 Ω, from SEM) were also attained by actuators composed of an IL-Cel electrolyte membrane without regenerated substances (from FT-IR and XRD). Actuators with a solid-state electric double layer capacitor using multi-wall carbon nanotubes as electrodes and [Emim]Ac-Cel as the polymer electrolyte, exhibited the highest specific capacitance of 890 mF g〈sup〉−1〈/sup〉 at 20 mV s〈sup〉−1〈/sup〉, a lower internal resistance (0.098 Ω g〈sup〉−1〈/sup〉) at range of 10〈sup〉5〈/sup〉 Hz–0.01 Hz, and the lowest power density (149 W kg〈sup〉−1〈/sup〉) at 10 A g〈sup〉−1〈/sup〉. Results indicated that cathode deflection was achieved by the action of van der Waals force and anion volumetric strain. These findings suggest that the developed mesoporous IL-Cel based actuators hold great promise in the further study of high-performance actuators.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321920-ga1.jpg" width="317" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Po-Yu Chu, Chia-Jung Liao, Chia-Hsun Hsieh, Hung-Ming Wang, Wen-Pin Chou, Ping-Hei Chen, Min-Hsien Wu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The heterogeneity of the drug resistance of cancer cells in a tumor is regarded as an important cause of therapeutic resistance and thus treatment failure. An understanding of the heterogeneity of cancer cells in a tumor in terms of their anti-cancer drug resistance is of great value for clinical applications or fundamental studies. To achieve this goal, a combination of cell-based drug testing and optically induced dielectrophoresis (ODEP)-based cell manipulation for sorting, separation, and isolation of drug-treated cells with various degrees of cell viability is proposed. For the latter, the key working principle is based on the difference in the ODEP force generated on the cells with various degrees of viability. To test the proposed idea, an ODEP microfluidic system was designed and fabricated in which two types of ODEP-based cell manipulation schemes were tested. The results successfully demonstrated that the proof-of-concept and practical application schemes were capable of effectively sorting, separating, and isolating doxorubicin-treated Dx5 (i.e., cells with drug resistance) and MES-SA (i.e., cells without drug resistance) cells that exhibited various degrees of viability and levels of anti-cancer drug resistance gene (i.e., 〈em〉ABCB1〈/em〉) expression. Moreover, the results also demonstrated that the proposed technique was capable of sorting and separating cell of the same type (i.e., drug-treated Dx5 cells) but different degrees of viability and anti-cancer drug resistance gene expression levels. Overall, this study presents a technique that is able to effectively sort, separate, and isolate drug-treated cancer cells with phenotypic heterogeneity for subsequent clinical applications or fundamental studies.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 283〈/p〉 〈p〉Author(s): Liangliang Huang, Yuanyuan Cao, Dongfeng Diao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, the graphene sheets embedded carbon (GSEC) film was modified with surface N-doping for highly selective ascorbic acid (AA) sensing. We found that the N-doped graphene sheets formed in-situ at the carbon film surface and induced high electrocatalytic activity for AA oxidation. Although surface N-doping slightly decreased the I〈sub〉D〈/sub〉/I〈sub〉G〈/sub〉 and surface roughness of carbon film, the graphene sheets embedded in amorphous were preserved. With surface N-doping, the charge-transfer resistance was reduced from 22.5 Ω cm〈sup〉2〈/sup〉 to 3.9 Ω cm〈sup〉2〈/sup〉, the oxidation-reduction peak separation decreased to a low value of 65.7 mV in Fe(CN)〈sub〉6〈/sub〉〈sup〉4−/3−〈/sup〉 redox system, and the standard rate constant was increased from 0.24×10〈sup〉-2〈/sup〉 to 1.36×10〈sup〉-2〈/sup〉 cm·s〈sup〉-1〈/sup〉. The surface N-doped graphene sheets embedded carbon (SN-GSEC) decreased the oxidation potential of AA from 0.186 V to 0.025 V (vs. Ag/AgCl) and realized selective detecting of AA. The mechanism may be that the surface N-doping induce the adjacent carbon in graphene sheets to obtain a higher partial density of states and more positive compensating charge. This study provides a simple method for preparing high performance electrochemical biosensor.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400518321981-ga1.jpg" width="361" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉