ALBERT

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Nohora Caicedo, Renaud Leturcq, Jean-Pierre Raskin, Denis Flandre, Damien Lenoble〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Metal-oxide nanowires are showing a great interest in the domain of gas sensing due to their large response even at a low temperature, enabling low-power gas sensors. However their response is still not fully understood, and mainly restricted to the linear response regime, which limits the design of appropriate sensors for specific applications. Here we analyse the non-linear response of a sensor based on ZnO nanowires network, both as a function of the device geometry and as a response to oxygen exposure. Using an appropriate model, we disentangle the contribution of the nanowire resistance and of the junctions between nanowires in the network. The applied model shows a very good consistency with the experimental data, allowing us to demonstrate that the response to oxygen at room temperature is dominated by the barrier potential at low bias voltage, and that the nanowire resistance starts to play a role at higher bias voltage. This analysis allows us to find the appropriate device geometry and working point in order to optimize the sensitivity. Such analysis is important for providing design rules, not only for sensing devices, but also for applications in electronics and opto-electronics using nanostructures networks with different materials and geometries.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Gang Xu, Chen Cheng, Wei Yuan, Zhaoyang Liu, Lihang Zhu, Xintong Li, Yanli Lu, Zetao Chen, Jinglong Liu, Zheng Cui, Jingjing Liu, Hong Men, Qingjun Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Last decade has seen a growing trend toward smartphone-based biochemical sensing systems. Meanwhile, flexible electrochemical sensing devices like wristbands, patches, and tattoos have been widely developed for 〈em〉in situ〈/em〉 detections of analytes in accessible biofluids. For these devices, the connectivity with smartphone and the flexibility of the whole device are hard to achieve at the same time, due to the need for rigid batteries or wired connections. Here, a smartphone-based battery-free and flexible electrochemical patch is developed for real-time calcium and chloride ions detections in various biofluids. The patch is integrated with near field communication (NFC) module, on-site signal processing circuitry, and an all-printed stretchable electrode array which can maintain stable conductivity during stretching, without the need for serpentine designs. The device enables wireless power harvesting, on-site signal processing, and wireless data transmission capabilities. NFC-enabled smartphones can wirelessly power the patch and get the detection results through inductive coupling between antennas. The calcium and chloride sensors showed good sensitivity, repeatability, selectivity, and stability in quantitative detections of target ions. 〈em〉Ex situ〈/em〉 measurements in serum, urine, tear, and sweat demonstrated good consistency with specialized instrument. Real-time on-body sweat analysis with the patch was also performed, which further indicated the usability and stability of the device in wearable applications. This platform provides a battery-free, wireless, and flexible solution for smartphone-based electrochemical sensing systems, which can be applied to rapid analysis of various biofluids.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092540051930944X-ga1.jpg" width="354" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Shuangming Wang, Jing Cao, Wen Cui, Longlong Fan, Xifei Li, Dejun Li, Tong Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉One dimensional porous Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 rectangular microrods (MR) are designed and successfully prepared by a distinctive electrospun precursor-hydrothermal regulation-annealing treatment strategy while Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanofibers (NF) are also synthesized for comparison by directly calcining precursors without hydrothermal treatment. The hydrothermal treatment before annealing process results in morphology and structure transition of Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 products from compact solid nanofibers to porous rods. When applied as a gas sensing material, Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 porous rods based sensors exhibit enhanced gas sensing properties in terms of rapid response time (3 s), recovery time (5 s), good selectivity and stability towards 100 ppm acetone gas at a relatively low working temperature of 200 °C. Meanwhile, the response of Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 porous rods toward 100 ppm acetone reaches approximately 5 times higher than that of solid Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanofibers. The enhanced acetone gas sensing properties of Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 rectangular porous rods are believed to originate from its porous structure and large surface area, facilitating gas adsorption and surface reaction and causing significant change in the thickness of holes accumulation layer (HAL). Feasible morphology-adjusting strategy and enhanced acetone gas sensing performances further highlight the advantage of as-prepared Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 porous rods in future acetone real-time monitoring.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Xiuyu Wang, Heng Li, Xuantong Zhu, Mengzhen Xia, Tao Tao, Binxin Leng, Wen Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A kind of ZnSn(OH)〈sub〉6〈/sub〉 crystalline precursor composed of micro- and nano-sized particles with two different morphologies was synthesized by co-precipitation method with the presence of triethanolamine (TEOA) as functional reagent. Zn〈sub〉1-〈/sub〉〈em〉〈sub〉x〈/sub〉〈/em〉Mg〈em〉〈sub〉x〈/sub〉〈/em〉Sn(OH)〈sub〉6〈/sub〉 samples (0≤〈em〉x〈/em〉≤0.5) were prepared by doping Mg〈sup〉2+〈/sup〉 ions in the synthesis process of ZnSn(OH)〈sub〉6〈/sub〉 precursor. Experimental results reveal that both the morphology and size of ZnSn(OH)〈sub〉6〈/sub〉 particles can be changed by TEOA and Mg〈sup〉2+〈/sup〉 ions, but not changed by dehydration at high temperature with the formation of Zn〈sub〉1-〈/sub〉〈em〉〈sub〉x〈/sub〉〈/em〉Mg〈em〉〈sub〉x〈/sub〉〈/em〉SnO〈sub〉3〈/sub〉 samples. When 〈em〉x〈/em〉 is 0.1, the effect of Mg〈sup〉2+〈/sup〉 ions on the morphology and size of ZnSn(OH)〈sub〉6〈/sub〉 particles is not remarkable, but the ethanol sensitivity of the resulting ZnSnO〈sub〉3〈/sub〉 sample at a low temperature of 80 °C is significantly improved by Mg〈sup〉2+〈/sup〉 ions at the conditions of nano-TiO〈sub〉2〈/sub〉 decoration and UV radiation. The ethanol response of the composite sample (ZM〈sub〉0.1〈/sub〉SO–T〈sub〉10〈/sub〉) is as high as ca. 149 at 500 ppm concentration, and its corresponding response and recovery time is about 4 s and 80 s, respectively. Furthermore, the sensor with ZM〈sub〉0.1〈/sub〉SO–T〈sub〉10〈/sub〉 also shows a good selectivity and long-term stability. Possible reasons for the superior ethanol sensitivity at low temperature were discussed.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉*Here ZnSnO〈sub〉3〈/sub〉 without Mg doping and Zn〈sub〉0.9〈/sub〉Mg〈sub〉0.1〈/sub〉SnO〈sub〉3〈/sub〉 with10% TiO〈sub〉2〈/sub〉 decoration samples prepared by this study are denoted as ZM〈sub〉0〈/sub〉SO and ZM0.1SO, respectively.〈/p〉 〈p〉In this study ZnSn(OH)〈sub〉6〈/sub〉 crystalline precursor composed of micro- and nano-sized particles with two different morphologies in (a) was synthesized by the control of the amount of triethanolamine (TEOA) as functional additive based on co-precipitation method. The −OH groups in TEOA can make ZnSn(OH)〈sub〉6〈/sub〉 cubic crystal nuclei adsorbed and connected together, resulting in the formation of a micro-sized cluster with cubic corners exposed (a). Usually, the cubic corners are corroded in the etching process [46], but those cubic corners of the micro-sized clusters in (a) are not corroded when nano-sized particles exist with them. However, Mg〈sup〉2+〈/sup〉 ions used for substitute for Zn〈sup〉2+〈/sup〉 ions by doping can counteract the role of TEOA in the synthesis of ZnSn(OH)〈sub〉6〈/sub〉 precursor. The cubic corners of the micro-sized clusters in (a) begin to be corroded when ZnSn(OH)〈sub〉6〈/sub〉 precursor is synthesized with the presence of a small number of Mg2+ ions (b), and no micro-sized clusters are formed if there are more Mg2+ ions in the synthesizing process. After dehydration of Zn〈sub〉1-〈/sub〉〈em〉〈sub〉x〈/sub〉〈/em〉Mg〈em〉〈sub〉x〈/sub〉〈/em〉Sn(OH)〈sub〉6〈/sub〉 precursor at high temperature, Zn〈sub〉1-〈/sub〉〈em〉〈sub〉x〈/sub〉〈/em〉Mg〈em〉〈sub〉x〈/sub〉〈/em〉SnO〈sub〉3〈/sub〉 was formed.〈/p〉 〈p〉Gas-sensing test reveals the following results: (1) The ZnSnO〈sub〉3〈/sub〉 (ZM〈sub〉0〈/sub〉SO) and Zn〈sub〉0.9〈/sub〉Mg〈sub〉0.1〈/sub〉SnO3 (ZM〈sub〉0.1〈/sub〉SO) samples, originating from the dehydration of samples in (a) and (b), respectively, have a high response to ethanol at a high temperature of 220 °C. The gas-sensing activity of ZnSnO〈sub〉3〈/sub〉 is greatly enhanced by Mg〈sup〉2+〈/sup〉 doping, as can be inferred from the gas response value of the two samples. (2) When nano-TiO〈sub〉2〈/sub〉 was used to decorate ZM〈sub〉0.1〈/sub〉SO, the resulting sensor under UV irradiation has a low operating temperature at a maximum gas response of 149, which is far more than that of our previous study [46].〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519309463-ga1.jpg" width="126" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Peng Lei, Ying Zhou, Ruiqi Zhu, Yang Liu, Chuan Dong, Shaomin Shuang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Iron phthalocyanine (FePc) functionalized nitrogen, boron–doped reduced graphene oxide (N,B–rGO) nanocomposite (FePc/N,B–rGO) was facilely fabricated for the first time as a electrochemical platform for sensitive detection of glutathione (GSH). FePc was immobilized on N,B–rGO substrate through π–π interaction, and N,B–rGO provided FePc with a large specific surface area to improve electron transfer and maintain its electrocatalytic activity. Cyclic voltammetric measurements showed that FePc and N,B–rGO triggered the synergistic effect and exhibited a satisfactory electrocatalytic activity. By integration of FePc and N,B–rGO, the FePc/N,B–rGO/GCE sensor displayed a wide linear dynamic range from 5.0 × 10〈sup〉–8〈/sup〉 M to 1.6 × 10〈sup〉–3〈/sup〉 M with a low detection limit of 7.1 × 10〈sup〉–9〈/sup〉 M. Besides, the electrochemical sensor presented satisfiable reproducibility, excellent anti–interference performance and long–term stability. The method was further expanded to determinate GSH in human serum sample with the recoveries between 95.0–109.0%.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519309578-ga1.jpg" width="378" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Bradley Ledden, Joe Bruton〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We developed a ring electrode sensor for down-stream electrochemical sensing of microfluidic ELISA assay. The sensor is designed to easily integrate into the flow environment. Noble metal inks on Low Temperature Co-fired Ceramic provide straight forward fabrication at the mesoscale yielding robust sensors with very low sensing volumes. Two different sensor geometries were modeled. The best design was fabricated and tested in both static and flowing solutions. The sensor exhibits both macroelectrode and microelectrode behavior depending on fluid flow rate. Sensors of this type may be ideal for applications where electrochemical detection is desired in a flowing solution since the ring electrode has low propensity for bubble trapping.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Nada F. Atta, Ahmed Galal, Yousef M. Ahmed, Ekram H. El-Ads〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cardiovascular disease is a class of diseases that involves the heart or blood vessels. It includes coronary artery diseases such as angina and myocardial infarction. In addition, hypertension is quantitatively the most important risk factor for premature cardiovascular disease. Dobutamine (DB) and amlodipine (AM) are medications commonly used for treating these diseases. Therefore, simultaneous determination of these drugs in presence of interfering compounds in biological fluids; paracetamol (PA), and ascorbic acid (AA) is essential for patients under medical treatment by these drugs. An innovative strategy is introduced for fabrication of a novel layered composite based on layer-by-layer modification of a glassy carbon electrode surface (GC) with multi-walled carbon nanotubes (CNT), ionic liquid crystal (ILC), graphene (RGO) and 18-Crown-6 (CW); (GC/CNT/ILC/RGO/CW). The layered sensor exhibited excellent electro-catalytic activity for determination of AA in the drugs mixture and simultaneous determination of DB, PA, and AM in human serum in linear dynamic ranges; 0.4 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mo〉→〈/mo〉〈/math〉 40 μM, 0.02 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mo〉→〈/mo〉〈/math〉 40 μM, 0.001 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mo〉→〈/mo〉〈/math〉 20 μM and 0.008 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mtext〉 〈/mtext〉〈mo〉→〈/mo〉〈/math〉 30 μM with low detection limit values; 9.24 nM, 0.497 nM, 0.0906 nM and 0.139 nM, respectively and low quantification limit values; 30.8 nM, 1.66 nM, 0.302 nM and 0.463 nM, respectively. Further practical application was performed for quantitative analysis of AA, DB, PA and AM in their pharmaceutical formulations.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519308482-ga1.jpg" width="392" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Xiangmei Li, Xinze Wu, Jin Wang, Qicheng Hua, Jinxiao Wu, Xing Shen, Yuanming Sun, Hongtao Lei〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, colloidal gold (CG), latex microspheres (LM), and time-resolved fluorescent microsphere (TrFM), were utilized as the antibody labeled tracers in three kinds of lateral flow immunochromatographic assays (LFIAs), which were established to detect tylosin (TYL) and tilmicosin (TIM) residues in milk and pork. The cut-off values of the CG-LFIA, LM-LFIA, and TrFM-LFIA for TYL in milk were 8, 4, and 2 ng/mL, respectively, and that for pork were 15, 8, and 4 μg/kg, respectively. The sample preparation of the three LFIAs is simple and fast, and the results can be acquired within 5-8 min. The three LFIAs have a strong cross-reaction to TIM and can be applied to simultaneously detect TIM. Forty milk samples were analyzed by both the three LFIAs and LC-MS/MS, the results showed a good correlation between the four methods, and no false positive or false negative results were found, indicating that the developed three assays could provide rapid, reliable, and multi-selective technical support for the on-site determination of macrolide antibiotics or other pollutants residues in a considerable amount of samples.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519312584-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Mohammad Khavani, Mohammad Izadyar, Mohammad Reza Housaindokht〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Different sensors composed of aptasensor have been largely designed for detection of many analytes recently due to the ease of detection, high sensitivity, and potential for high-throughput analysis. In this article, a joint theoretical and experimental study was performed to design new gold nanoparticle based colorimetric aptasensor. At the first step, by employing molecular dynamic (MD) simulations, twenty new RNA aptamers for detection of neomycin B (NB) were theoretically designed. The sensing ability and their binding affinity of these aptamers toward NB were investigated from the theoretical viewpoint and the predicted behaviors were compared with that of the wild type aptamer (AP-W). Theoretical results indicated that two aptamers of AP-M18 and AP-M20 have a greater affinity toward NB in comparison with AP-W. At the next step, AP-M18, AP-M20 and AP-W were synthesized and their affinity and selectivity toward NB were investigated by gold nanoparticles (AuNPs) based colorimetric method. On the basis of experimental results, the calculated limit of detection (LOD) values of AP-M18 and AP-M20 are 27 and 360 nM, respectively, which are lower than that of AP-W (470 nM). Moreover, quantum chemistry calculations indicated that van der Waals and electrostatic interactions may be the driving force of the NB complexation. A greater affinity of AP-M18 against NB can be explained by the possible stronger donor-acceptor interactions. A good agreement between different predicted properties with the experimental results suggests the ability of the theoretical methods to design new aptamers for detection of various targets.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311463-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈p〉Experimental investigation indicates that the theoretical methods have an interesting ability for designing new aptasensors for detection of different targets.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Xiaohui Lu, Jin Wang, Guodong Lu, Bo Lin, Meizhuo Chang, Wei He〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉China grows and consumes numerous types of tea, which have diverse processing techniques. West Lake Longjing Tea is one of the most famous and popular varieties of tea in China. It is difficult for consumers to assess the quality of Longjing green tea, as it usually requires well-trained experts to make the judgement based on colour, aroma, and taste. To this end, we propose a quality identification system consisting of a self-developed electronic nose and a data analysis algorithm to assess the quality of West Lake Longjing Tea based on its aroma. The equipment was tested extensively in experiments conducted on real-world data. The results show that the proposed system is capable of distinguishing the tea grades accurately. Furthermore, we studied the quality specifications of Longjing tea sold by different brands and found that standard certified brands have more accurate quality identification criteria than non-standard certified brands. Our findings will assist customers and tea factories in evaluating the quality of Longjing Tea and guide the optimisation of quality standards.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 300〈/p〉 〈p〉Author(s): Hao Guo, Kun Qian, Anjiang Cai, Jun Tang, Jun Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We demonstrate a method for fabricating nanoparticles in a line at the top of silver wrinkled structures by tilting the substrate. The center of gravity of the colloidal droplets was moved backward, resulting in a small volume of droplets at the front of the colloidal droplet. The droplet rapidly evaporated, and the nanoparticles that remained formed lines of highly ordered nanoparticles. The distance between the nanoparticles changed after stretching the PDMS substrate due to the Poisson effect. An optimal plasma effect was achieved by controlling the distance between the nanoparticles. Finally, the Surface-Enhanced Raman Scattering (SERS) effects of CV and R6G molecules in water were determined, and the detection limit was 10〈sup〉−20〈/sup〉 M. This method provides an extremely high sensitivity SERS substrate for the detection of biomolecules.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Jin Her, Hunho Jo, Changill Ban〈/p〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Gao-Chao Fan, Zimeng Li, Yanwei Lu, Linzheng Ma, Huan Zhao, Xiliang Luo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Resulting from nonspecific adsorption or obvious biofouling, target detection in real biological media is a potential challenge for most of the biosensors. Herein, we first report an antifouling photoelectrochemical (PEC) cytosensor by using zwitterionic peptide. The typical cervical carcinoma Henrietta Lacks (HeLa) cell was chosen as a target model and the aptamer AS1411 was used as its recognition element. TiO〈sub〉2〈/sub〉 nanoparticles (NPs) and ZnIn〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 nanocrystals (NCs) were modified in order on a bare indium–tin oxide (ITO), forming ITO/TiO〈sub〉2〈/sub〉/ZnIn〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 electrode as the PEC matrix to immobilize aptamer AS1411 and zwitterionic peptide. The fabricated PEC cytosensor exhibited a high sensitivity toward HeLa cell detection, with the detection limit of 34 cells/mL. Besides, owning to excellent antifouling property of the zwitterionic peptide, evidently reduced nonspecific adsorption of the cytosensor was realized in the biological media.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉An efficient but general strategy for antifouling photoelectrochemical cytosensor was proposed by introducing zwitterionic peptide. The cytosensor demonstrated the distinct merits of high sensitivity and low fouling in the biological media.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311955-ga1.jpg" width="283" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Xiang Tao, Tan Dai Nguyen, Hao Jin, Ran Tao, Jingting Luo, Xin Yang, Hamdi Torun, Jian Zhou, Shuyi Huang, Lin Shi, Des Gibson, Michael Cooke, Hejun Du, Shurong Dong, Jikui Luo, YongQing Fu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Manipulating biological cells or microparticles in three dimensions (3D) is invaluable for many biomedical applications, and recently effective and rapid manipulations of microparticles in 2D and 3D within microchannels or chambers using surface acoustic waves (SAWs) with bulk piezoelectric materials have been reported. However, these are generally expensive, or brittle and cannot be easily integrated into a single lab-on-chip. In this paper, we realized microparticle/cell patterning and 3D manipulation of yeast cells inside a chamber with a height of 1 mm using thin film ZnO/Si SAW devices. Effects of SAW frequency, channel width and thickness on alignment of microparticles were firstly investigated, and positions of the microparticles in the direction of SAW propagation can be controlled precisely by changing the phase angle of the acoustic waves from the ZnO/Si SAW device. A numerical model has been developed to investigate the SAW acoustic field and the resulted 3D motions of microparticles under the acoustic radiation forces within the microchamber. Finally, we realized and observed the 3D patterning of yeast cells within the microchannel. Our work shows a great potential for acoustofluidic, neural network research and biomedical applications using the ZnO/Si SAW devices.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Oleg Lupan, Vasile Postica, Thierry Pauporté, Bruno Viana, Maik-Ivo Terasa, Rainer Adelung〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we investigated performances of individual and multiple networked Au nanoparticles (NPs)-functionalized ZnO nanowires (NWs) integrated into nanosensor devices using dual beam focused ion beam/scanning electron microscopy (FIB/SEM) and tested them as gas sensors at room temperature. Such important parameters as diameter and relative humidity (RH) on the gas sensing properties were investigated in detail. The presented results demonstrate that thin Au/ZnO NWs (radius of 60 nm) have a gas response of 〈em〉I〈sub〉gas〈/sub〉/I〈sub〉air〈/sub〉〈/em〉 of about 7.5–100 ppm of H〈sub〉2〈/sub〉 gas which is higher compared to 〈em〉I〈sub〉gas〈/sub〉/I〈sub〉air〈/sub〉〈/em〉 of about 1.2 for NWs with a radius of 140 nm. They have a low dependence of electrical parameters on water vapors presence in environment, which is very important for practical and real time applications in ambient atmosphere. Also, the devices based on multiple networked Au/ZnO NWs demonstrated a higher gas response of 〈em〉I〈sub〉gas〈/sub〉/I〈sub〉air〈/sub〉〈/em〉 about 40 and a lower theoretical detection limit below 1 ppm compared to devices based on an individual NW due to the presence of multiple potential barriers between the NWs. The corresponding gas sensing mechanisms are tentatively proposed. The proposed concept and models of nanosensors are essential for further understanding the role of noble metal nanoclusters on semiconducting oxide nanowires and contribute for a design of new room-temperature gas sensors.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311761-ga1.jpg" width="265" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Ye Liu, Fei Zhou, Hongcheng Wang, Xiaoyuan Huang, Dongxiong Ling〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Coffee-ring structures, which are easy to prepare, have many hotspots for surface-enhanced Raman scattering (SERS). However, the inhomogeneous distribution of hotspots causes very poor SERS detection reproducibility, which strongly restricts their practical applications. In this paper, by combining a coffee-ring structure with the waveguide effect of optical fibers, we propose novel micro-coffee-ring-patterned fiber SERS probes fabricated by a laboratory-developed laser-induced dynamic dip-coating method. The mechanisms of micro-coffee-ring formation on fiber facet are analyzed in detail. With the help of a programmable dip-coater, micro-coffee-ring-patterned fiber SERS probes can be automatically and reproducibly fabricated, and they simultaneously show high sensitivity and good reproducibility in SERS detections. A detection limit lower than 10〈sup〉−8〈/sup〉 M in aqueous solvent for thiram and methyl parathion (MP) is achieved, and the relative standard deviation (RSD) of the SERS peaks is less than 6%. In addition, benefiting from numerous hotspots provided by micro-coffee rings, this micro-coffee-ring-patterned fiber SERS probe presents superior performance in 〈em〉in-situ〈/em〉 trace detection of target molecules in complex liquid environments. Detection sensitivities of 10〈sup〉−7〈/sup〉 M for thiram in lake water and in orange juice and 10〈sup〉−6〈/sup〉 M for melamine and tetracycline in liquid milk are achieved.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Xiaofang Qiao, Zhiming Ma, Lihui Si, Wei Ding, Guangmeng Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, a lanthanide cation, Eu(III), was firstly coordinated with a series of organic antenna ligands and then doped into bio-MOF-1 via cation exchange for O〈sub〉2〈/sub〉 optical sensing. These organic ligands were supposed to increase dynamic collision probability between O〈sub〉2〈/sub〉 molecules and excited probe molecules, so that sensitivity could be increased and response time could be decreased. These composite samples were firstly identified using SEM, XRD, N〈sub〉2〈/sub〉 adsorption/desorption and ICP measurement to confirm their microstructure. Then their absorption spectra, emission spectra and emission lifetimes were discussed. It was found that these composite samples showed long emission lifetime up to 595 μs, which ensured enough time for O〈sub〉2〈/sub〉 collision. Their O〈sub〉2〈/sub〉 sensing performance was discussed via their emission spectra under increasing O〈sub〉2〈/sub〉 concentrations. Linear sensing curves were observed for all samples. It was found that a large conjugation plane improved sensitivity and decreased response time since this large conjugation plane increased dynamic collision probability. The sensing mechanism was confirmed as the O〈sub〉2〈/sub〉 quenching on long-range energy roll-back from ligand triplet state to bio-MOF-1. The highest sensitivity and the shortest response time were obtained as 6.96, three times higher than literature values, and 12 s, respectively.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311773-ga1.jpg" width="276" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Naveen Kumar Sompalli, Akhila Maheswari Mohan, C.V.S. Brahmananda Rao, Sivaraman Nagarajan, Prabhakaran Deivasigamani〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present a facile approach towards the fabrication of solid state optical sensors for the naked-eye sensing of carcinogenic Cr〈sup〉6+〈/sup〉 ions, using porous polymer and silica monoliths, as probe anchoring templates. The monoliths proffer superior structural properties of high surface area and capacious pore size for the uniform and voluminous probe anchoring. The surface morphology and structural features of the monoliths are analyzed using various surface and structural characterization techniques. The solid-state optical sensors are concocted by the transmogrification of monoliths through impregnation of an amphipathic chromoionophore 〈em〉i.e.〈/em〉, 〈em〉1,5〈/em〉-bis-(〈em〉4〈/em〉-butylphenyl)carbazone (BBPC), as the ion-sensing probe. The sensors offer long-term stability and rapid response kinetics (〈 10 min) with superior ion-selectivity for ultra-trace Cr〈sup〉6+〈/sup〉 ions. The ascendancy of physicochemical parameters with reference to solution pH, probe concentration, response kinetics, medium temperature, sensor capacity, linear signal response, selectivity, and sensitivity has been optimized. The sensors exhibit a linear signal response for Cr〈sup〉6+〈/sup〉 ions in the concentration range of 5–125 ppb and 3–150 ppb, for silica and polymer sensors, respectively. The solid-state sensor systems exhibit excellent data reliability and reproducibility (RSD ≤ 2.85%), with an L〈sub〉D〈/sub〉 of 1.87 and 0.41 ppb, and an L〈sub〉Q〈/sub〉 of 6.23 and 1.36 ppb, for silica and polymer sensors, respectively.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310950-ga1.jpg" width="461" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Xiaowei Li, Chaohan Han, Dongxiao Lu, Changlu Shao, Xinghua Li, Yichun Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The size of sensing materials matters a lot to the performance of gas sensors. Herein, size-controlled three-component ZnO/ZnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/Au nanomeshes were elaborately prepared by combining electrospinning, atomic layer deposition and room-temperature solution reaction methods. The as-prepared ZnO/ZnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/Au is characterized by uniform ZnO nanotube skeletons (˜50 nm), ultrathin ZnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 nanosheets (˜10 nm) and well-dispersed Au nanoparticles. To demonstrate the superiority of such ultrafine ZnO/ZnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/Au nanomeshes, a comparison of sensing performance between the gas sensors fabricated by pristine ZnO, ZnO/ZnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 and ZnO/ZnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/Au was carried out. Results of the measurement evidence that the sensor based on ZnO/ZnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/Au nanomeshes exhibited the highest sensing response, significantly enhanced selectivity, and faster response/recover speed compared with the other two reference counterparts. The response of ZnO/ZnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/Au towards acetone was improved about 3-fold versus the ZnO/ZnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 composites and 5.5-fold versus pristine ZnO. The enhanced gas sensing performance was found to be closely related to the highly electron-depleted layer derived from the small material size and the interfacial heterojunctions as well as the sensitization effect endowed by the Au nanoparticles. This study shows the great potential of ZnO/ZnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/Au nanomeshes on acetone detection and provides a promising mean for the rational design of high-performance gas sensor.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Mingquan Pi, Chuantao Zheng, Ran Bi, Huan Zhao, Lei Liang, Yu Zhang, Yiding Wang, Frank K. Tittel〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The reported chalcogenide (ChG) waveguide sensor mainly focuses on rectangular waveguide with a small evanescent field for light-gas interaction. In order to improve the sensing performance in the mid-infrared spectral range and ease wavguide fabrication, a suspended ChG/silica-on-silicon slot-waveguide gas sensor was proposed, where ChG was used as the core layer, silica was adopted as the lower buffer as well as a support layer with the silica under the waveguide core removed. The new sensor structure resulted in an increased light-gas interaction, a decreased waveguide loss in the mid-infrared and a small depth-to-width ratio for feasible slot fabrication. The optimized suspended slot waveguide reveals a large power confinement factor (PCF) of 85.77% at 3291 nm. CH〈sub〉4〈/sub〉 was adopted as the target gas for performance evaluation of the ChG/silica-on-silicon slot-waveguide sensor at the absorption line of 3038.5 cm〈sup〉−1〈/sup〉. An optimal waveguide length of 1.45 cm was determined with a waveguide loss of 3 dB/cm for maximizing the sensitivity. The response time is as short as 〈3 μs due to the exposure of the waveguide sensing area to the atmosphere. The limit of detection (LoD) was decided to be 1.70 parts-per-million (ppm) for a minimum detectable signal-to-noise ratio of 10. Effects of ambient temperature/pressure change and fabrication error on the sensor performance were discussed. The proposed suspended ChG/silica-on-silicon slot-waveguide sensor possesses a ∼ 10 times larger PCF than other reported ChG rectangular waveguide sensors in the mid-infrared and reveals an improved performance for potential environmental monitoring and wearable gas sensing applications.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Thitarat Prathumsuwan, Panichakorn Jaiyong, Insik In, Peerasak Paoprasert〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, we reported a simple strategy for the synthesis of highly fluorescent carbon-based nanomaterials from one of the world’s most invasive aquatic plants and investigated their uses as practical, low-cost borax sensors, which have not been reported elsewhere to date. The carbon dots (CDs) were synthesized through acid-treatment-assisted pyrolysis with water hyacinth leaves as a precursor. Quasi-spherical CDs in solution were shown to produce blue emission, at a relatively high quantum yield of 27%. Their use as a borax probe was demonstrated with a detection limit of 1.5 μM. The selectivity and sensitivity of CDs toward borax in the presence of interferences confirmed their unique and selective sensing properties. A portable paper-based device was fabricated for use in on-site borax detection and was shown to have a detection limit 11.85 μM. Real fish ball samples were tested, and the CDs exhibited excellent borax recovery, in the range 98.8–101.8%. Our computational findings based upon density functional theory (DFT) and time-dependent density functional theory (TD-DFT) suggested that selective fluorescence quenching arose from charge transfer between the CDs and borax 〈em〉via〈/em〉 their favorable lowest unoccupied molecular orbitals. Both experimental and computational findings therefore confirmed the novel sensing properties of the CDs.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311359-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): XinXin He, Shwu Jen Chang, Kalpana Settu, Ching-Jung Chen, Jen-Tsai Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As the number of diabetic patients increases year by year, the demand for a self-monitoring blood glucose test also increases. Additionally, more in-depth studies of blood glucose biosensors have led to increasing accuracy requirements. However, at present, most enzyme glucose sensors have difficulty solving issues related to hematocrit (HCT) interference. Most studies on anti-HCT interference in blood glucose sensing have mainly focused on correction factors, such as glucose correction, and electrical impedance or resistivity characteristics to correct the impact of HCT. In this work, we developed an anti-HCT-interference blood glucose sensor based on a fiber paper-based screen-printed carbon electrode with a mediator (potassium ferricyanide) and glucose oxidase (GOD), which were fixed through inkjet printing. When testing whole blood samples with HCT levels of 20%–70% and a fluid dropping method, the results of a consensus error grid analysis showed that 91% of the data points lied within zones A and B. The glucose sensor was exclusively designed with a 16 μL chamber in the working area of the sensor. When the testing fluid was taken in by capillary sucking, the effect of HCT was further reduced, and 95% of the data points lied within zones A and B in the consensus error grid.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Hongye Yan, Lei Jiao, Hengjia Wang, Weiqing Xu, Yu Wu, Wenling Gu, Dan Du, Yuehe Lin, Chengzhou Zhu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Enzyme-linked immunosorbent assay (ELISA) has been widely used in the area of biological analysis, while there are still some challenges getting in the way to ensure both excellent sensitivity and reliable accuracy. To overcome these obstacles, we simulated the “smart” sense-and-treat carriers in a drug delivery system to fabricate an improved ELISA, employing zeolitic imidazolate framework-8 (ZIF-8) as the carrier to deliver the tracer agent carbon dots (CDs) and the “drug” thymolphthalein (TP), which was referred to as a “sense-and-treat” ELISA. In the “sense” part, the strong fluorescence intensity of CDs could be observed directly to achieve the sensitive detection of the target. In the “treat” part, after stimulation of alkaline solution, TP was released from ZIF-8 carriers and generated a color change with an obvious absorption, which was beneficial for increasing the sensitivity of this ELISA due to the high loading of the TP. Finally, we took carcinoembryonic antigen (CEA) as a model and performed dual-modal detection using this improved “sense-and-treat” ELISA to accomplish quantitative determinations sensitively and accurately. In addition, the results indicated by the two parts kept good concordance, which could demonstrate the reliable accuracy of this ELISA.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Priyan Weerappuli, Taisuke Kojima, Shuichi Takayama, Amar Basu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The use of monolithic normally-closed (NC) valves within microfluidic systems is currently limited by the poor scalability of mitigation strategies developed to prevent the formation of a permanent bond between the valve ‘seat’ and elastomeric membrane during fabrication. Herein we report the highly-scalable design and characterization of a slightly-open doormat (SOD) valve that exhibits properties traditionally associated with NC valves including operability at low actuation pressures, and the capacity to produce a complete seal. In addition, these valves are comparable in their scalability and in responsiveness, and exhibit a capacity to eliminate resting channel resistance that is absent in their NC counterparts. We demonstrate the utility of this novel valve design through the design and operation of a gas-on-gas multiplexer containing 32 device valves controlled by a multiplexer containing 160 SOD valves using only 10 external solenoid valves and a single common pressure source.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519309761-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 297〈/p〉 〈p〉Author(s): Yueying Zhang, Ce Ma, Xinyu Yang, Yang Song, Xishuang Liang, Xu Zhao, Yilin Wang, Yuan Gao, Fengmin Liu, Fangmeng Liu, Peng Sun, Geyu Lu〈/p〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Daiki Kawasaki, Kenichi Maeno, Hirotaka Yamada, Kenji Sueyoshi, Hideaki Hisamoto, Tatsuro Endo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Metal nanostructures have great potential for optical label-free biosensors based on localized surface plasmon resonance (LSPR). The sensitivity of a metal nanostructure-based label-free biosensor (i.e., plasmonic sensor) depends on its plasmonic properties, which suffer a decrease in sensitivity by energy losses in the metal material. Here, we demonstrate an approach to improve the plasmonic properties of metal nanostructures by controlling the carrier density in the base polymer material using titanium nitride (TiN). It is expected that the light energy absorbed by TiN is converted into excitons, and it will assist LSPs in the metal nanostructure; thus, the losses of the metal material are compensated by the excitons excited in TiN. We designed a TiN-contained polymer-metal/core-shell structured nanocone array (NCA), comprising TiN nanoparticles (NPs) in a polymer core and metal shell (Au or Ag), and realized improvement of the refractive index (RI) sensitivity of a label-free biosensor by optimizing the TiN-contained polymer composition. As a result, the TiN-contained polymer-metal NCA, with a TiN NP concentration of 10 wt% in the polymer core, had a 1.5-fold higher RI sensitivity than that of the same NCA without TiN NPs. The results of the resistance measurement of the metal surface with the TiN NP-contained polymer (10 wt%) under light exposure suggest the conversion of exposed light into LSPs of metal via TiN. It is suggested that plasmonic properties and sensor performances can be improved by the presented approach. Moreover, in DNA hybridization detection, an extremely low limit of detection of 117.5 fM was achieved.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311311-ga1.jpg" width="436" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Jin-Young Kim, Jae-Hyoung Lee, Jae-Hun Kim, Ali Mirzaei, Hyoun Woo Kim, Sang Sub Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we fabricated pristine and Pd-functionalized CuO nanowires (NWs) for H〈sub〉2〈/sub〉S gas sensing. The CuO NWs were synthesized using a vapor–liquid–solid method and the Pd functionalization was achieved by ultraviolet irradiation of a Pd precursor solution in the presence of the CuO NWs. The characterization results confirmed the formation of pristine and Pd-functionalized CuO NWs with favorable compositions and morphologies. The gas-sensing response of the NWs towards H〈sub〉2〈/sub〉S was enhanced by the Pd functionalization, at 25–100 °C. Moreover, self-heating tests showed that the Pd-functionalized gas sensors exhibited a selective response to H〈sub〉2〈/sub〉S gas when a low voltage (5 V) was applied. The superior performance of the Pd-functionalized gas sensor was attributable to not only the catalytic effects of both CuS and Pd but also the CuO/Pd heterostructures. The results demonstrate that the fabricated H〈sub〉2〈/sub〉S sensors are energy-efficient and could be used in various electronic devices.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Schematic of sensing mechanisms in Pd-decorated CuO nanowires〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311645-ga1.jpg" width="295" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Min Sun Park, Jun Ho Lee, Yunji Park, Ran Yoo, Seungryol Park, Hwaebong Jung, Wonkyung Kim, Hyun-Sook Lee, Wooyoung Lee〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report on the doping effect on the sensing properties of ZnO quantum dots (QDs) for the detection of acetylene. We found that In-doped ZnO (IZO) QDs exhibited a better sensing performance to 10 ppm acetylene than undoped ZnO (ZO) QDs and Al-doped ZnO (AZO) QDs. The higher sensing response of IZO QDs can be attributed to a greater number of reactive sites for detecting acetylene, which is likely to originate from the increased number of oxygen vacancies, and the larger optical band gap and surface area of IZO. This is due to a higher valence dopant and a smaller particle size. The sensing properties of IZO QDs to 10 ppm acetylene was also found to be superior to previously reported acetylene sensors that are based on semiconducting metal oxides. Furthermore, we demonstrated that 10 ppm of acetylene can be selectively detected in air within ∼100 s using a recently developed miniaturized gas chromatography (GC) integrated with the IZO QDs sensor. In addition, we found that the device can detect the major fault gases of hydrogen and acetylene separately within ∼100 s. Our study demonstrates that the device can be utilized in the GC-based on-line dissolved gas analysis to detect small amounts of acetylene gas in transformer oil.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Lintao Zeng, Xiaoli Wu, Qiao Hu, Hou-Qun Yuan, Guang-Ming Bao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The abuse of bisulfite and benzoyl peroxide (BPO) in food can cause serious damage to humans, hence, it is necessary to determine bisulfite and BPO in food. In this paper, we presented a fluorescence chemosensor (〈strong〉PTCA〈/strong〉) for discriminative detection of bisulfite and BPO with differential fluorescence based on different chemical reactions. 〈strong〉PTCA〈/strong〉 exhibited blue fluorescence turn-on response towards bisulfite with good selectivity, fast response (〈 5 min) and a low detection limit (288 nM). By contrast, 〈strong〉PTCA〈/strong〉 displayed an obvious green fluorescence enhancement in response to BPO with good selectivity, fast response (〈 8 min), as well as a low detection limit (34 nM). This chemosensor was successfully demonstrated for determining HSO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 and BPO in several food samples with good recoveries (90∼111%). Furthermore, 〈strong〉PTCA〈/strong〉 was fabricated into paper-based test stripes for visual determination of HSO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 and BPO in food.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311931-ga1.jpg" width="337" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Mengqi Zou, Xia Li, Daxiu Li, Ruo Yuan, Yun Xiang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The interactions between proteins and DNA play critical roles in numerous essential cellular activities. Therefore, sensitive investigation of these interactions is crucial for the study of different biological activities. Hence, a convenient and enzyme-free sensing approach for homogeneous and ultra-sensitive assay of transcription factors was explored based on the steric hindrance-protected Mg〈sup〉2+〈/sup〉-DNAzyme amplification strategy. The target proteins can specifically bind the unique sequences of the Y-shaped DNA probes with strong affinity to form the protein/DNA complexes and to protect them from being disrupted by the external invading DNA. The target-protected and intact Mg〈sup〉2+〈/sup〉-DNAzymes further hybridize with the fluorescently quenched DNA hairpin substrate sequences and cleave them cyclically to yield substantially enhanced fluorescence response for amplified detection of transcription factors. Using nuclear factor kappa B p50 as the example target, a low detection limit down to 2.8 pM can be achieved. Besides, the approach also exhibits excellent selectivity due to the high specificity of the recognition regions and can be further applied in human serums. This sensing platform thus can expect to be a promising alternative for the sensitive analysis of multiple DNA-binding proteins by changing the corresponding recognition units.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310640-ga1.jpg" width="291" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Wangchi Zhou, Zhiheng Xu, Danny Ross, James Dignan, Yingzheng Fan, Yuankai Huang, Guiling Wang, Amvrossios C. Bagtzoglou, Yu Lei, Baikun Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study examined flat thin mm-sized soil moisture sensors (MSMS) fabricated using thermal press technology on thin compact disc (CD) to solve the long-standing problems of soil moisture profiling. The 10-month field tests conducted at a farm site compared three groups of MSMS with commercial capacitance-type soil moisture sensors (SMS) in terms of accuracy, sensitivity to environmental variations (e.g. water shock, temperatures, dry/wet seasons) and long-term stability. MSMS sensors were mounted on the shallow, middle and deep locations of a hollow plastic rod (length: 1.1 m) and installed along the soil depth to profile the soil moisture variation. The resistance readings of MSMS sensors along soil depth were recorded in a real-time mode. Due to soil settlement over time after installation, the MSMS sensors in the shallow soil suffered from unstable readings, while the MSMS sensors in the middle and deep soil exhibited high stability and had the best correlation with water content values of commercial sensors (R〈sup〉2〈/sup〉 value: 0.6264). The contact between MSMS surface and soil particles appeared to be a critical factor determining the stability of MSMS readings. In addition, MSMS sensors showed a prompt response to the sharp change of soil moisture in the water shock tests. The soil moisture profiles collected from MSMS sensors captured the spatiotemporal variation of soil moisture, which enabled the simultaneous profiling at multiple locations. This field study demonstrated the great potential of mass deployment of low-cost but accurate MSMS sensors to achieve high resolution profiling for water-saving irrigation.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310561-ga1.jpg" width="340" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Ainhoa Gonzalez-Pujana, Edorta Santos-Vizcaino, Maite García-Hernando, Beatriz Hernaez-Estrada, Marian M. de Pancorbo, Fernando Benito-Lopez, Manoli Igartua, Lourdes Basabe-Desmonts, Rosa Maria Hernandez〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the search of biomaterials that promote cell adhesion, it is crucial to explore the integrin-substrate dynamic interactions given in a certain cell type to design successful biofunctionalization strategies. Here, we use a microarray platform for a thorough characterization of cell adhesion to a particular substrate. A biosensor based on an array of 20 μm fibronectin circular isles was adapted to tissue culture treated plates to facilitate the performance of cell adhesion assays and the posterior affinity analyses. This sensitive analytical tool enables not only the evaluation of the cell adhesion kinetics, but also the integrin profiling and their contribution to cell attachment and adhesion strengthening via clustering. In particular, the biosensor was able to detect a significantly slower adhesion kinetics in fibroblasts, namely Baby Hamster Kidney Fibroblasts (BHK) and Human Dermal Fibroblasts (hDF), in comparison to other cell types such as C〈sub〉2〈/sub〉C〈sub〉12〈/sub〉 Mouse Myoblasts (C〈sub〉2〈/sub〉C〈sub〉12〈/sub〉) or Human Mesenchymal Stem Cells (hMSCa). When directly comparing hDF and hMSCa, the analysis determined that the differing kinetics were caused by a distinct integrin expression profile. Whereas β〈sub〉1〈/sub〉-presenting integrins were the major responsible for hDF attachment, hMSCa adherence was importantly dependent on β〈sub〉1〈/sub〉 but also on other integrin classes. Additionally, results revealed that concerning cell adhesion consolidation, in hMSCa, both α〈sub〉v〈/sub〉β〈sub〉3〈/sub〉 and β〈sub〉1〈/sub〉-subunit-presenting integrins contributed similarly; whereas in hDF, the latter played a more important role. Hence, our biosensor provided crucial information for the development of new cell-adhesive biomaterials, which are key in multiple biomedical fields including cell therapy or tissue engineering.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311530-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Jianhua Sun, Lixia Sun, Ning Han, Haomiao Chu, Shouli Bai, Xin Shu, Ruixian Luo, Aifan Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The novel sensing materials of rGO decorated CdS/CdO heterojunction have been synthesized successfully for the first time by a facile one-step hydrothermal method combining with calcination treatment. The structure, morphology, composition, and specific surface of the composite were characterized by XRD, SEM, XPS spectra and BET analysis, respectively. The gas sensing properties to 2 ppm of NO〈sub〉2〈/sub〉 were examined. The results show that the 4.0 wt % rGO/CdS/CdO composite not only exhibits 9 times higher response and 4.75 times lower detection limit than that of pristine CdS, but also owns rapid response and recovery, indicating the composite is a promising novel sensing material for detecting of low-concentration NO〈sub〉2〈/sub〉. The enhancement mechanism was also discussed in detail, which benefits from the formation of the heterojunctions between CdS and CdO and the decoration of rGO. rGO also as an efficient electron mediator increases gas adsorption and accelerates electron transfer of the composite.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉The composites of CdS/CdO/rGO have been successfully synthesized by one step hydrothermal method. The 4.0 wt% rGO decorated composite not only enhances the response compared with the CdS and CdS/CdO, but also shows rapid response and stability to 2 ppm NO2 at operating temperature of 125 °C. The mechanism of enhancing NO2 sensing performance can be attributed to the formation of heterojunction and the decoration of rGO.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310317-ga1.jpg" width="200" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Hao Wan, Ying Gan, Jiadi Sun, Tao Liang, Shuqi Zhou, Ping Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Gas sensors have received extensive attractions due to their critical roles in environmental monitoring, industry manufacture and human safety. This paper for the first time introduces carbon-gold nanocomposites on a reduced graphene oxide based electrochemical gas sensor for high sensitive gas detection. Carbon-gold nanocomposites (CGNs) were synthesized by glucose carbonization and gold nanoparticles deposition using the hydrothermal method. Reduced graphene oxide (RGO) was electrochemically deposited on a screen-printed gold electrode with subsequent modification of CGNs. To achieve long lifetime and good stability, thin-film room temperature ionic liquid (RTIL) was utilized as the electrolyte featuring negligible evaporation and large potential window, thus implementing the high sensitive RTIL-based electrochemical gas sensor. The amplification effect of RGO and CGNs modification was investigated using cyclic voltammetry, chronoamperometry and transient double potential amperometry (DPA), which reveals the significant enhancement of sensor performance by synergic application of RGO and CGNs. The sensor was calibrated for oxygen detection from 0.42% to 21% with good sensitivity and linearity. The reproducibility of the sensor using chronoamperometry and transient DPA was also studied with excellent reproducibility. The study paves a new way to implementing high sensitive electrochemical gas sensors for rapid monitoring of gas exposure.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A reduced graphene oxide and carbon-gold nanocomposite modified room temperature ionic liquid based electrochemical gas sensor for high sensitive gas detection.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311517-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Chao Wang, Bin Yang, Jinlong Xu, Feng Xia, Jianzhong Xiao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The influences of sensing electrode morphology, operating temperature and the oxygen content on NH〈sub〉3〈/sub〉 sensing properties for the potentiometric gas sensor attached with CeVO〈sub〉4〈/sub〉 sensing electrode were studied. With the increase of electrode sintering temperature, CeVO〈sub〉4〈/sub〉 grains grow up gradually. The response/recovery time shows a decreasing trend, but the NH〈sub〉3〈/sub〉 sensitivity reaches the highest when the sintering temperature reaches 1000 °C, this was determined by the amount of TPB and the ammonia concentration involved in the electrode electrochemical reactions. The NH〈sub〉3〈/sub〉 sensitivity enhances with the increase of operating temperature in the range of 450–550 °C and presents the mixed-potential characteristic. When the temperature exceeds 600 °C, the curve between ΔV and logarithm of NH〈sub〉3〈/sub〉 concentration presents a broken line relationship, and the concentration corresponding to the inflection point increases with the increase of operating temperature. The response and recovery rates accelerate but the NH〈sub〉3〈/sub〉 sensitivity decreases with the increase of oxygen content in testing gas. When the oxygen is above 10 vol.% and NH〈sub〉3〈/sub〉 is below 80 ppm, the response value is almost unaffected by the change of oxygen concentration. The broken line feature of the sensitivity curve under high operating temperatures and oxygen concentrations is mainly related to the gas phase catalytic reaction of NH〈sub〉3〈/sub〉 by oxygen.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Tihana Mudrinić, Sanja Marinović, Aleksandra Milutinović-Nikolić, Nataša Jović-Jovičić, Marija Ajduković, Zorica Mojović, Predrag Banković〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cobalt oxide supported on pillared clay was synthesized and used as modifier of carbon paste electrode. Cyclic Voltammetry and Impedance Spectroscopy were employed to evaluate the performance of investigated electrode in NaOH solution with and without glucose. The experimental conditions such as concentration of OH〈sup〉−〈/sup〉 ion and the amount of modifier in carbon paste electrode were optimized in order to achieve the highest response for the investigated electrode material. The results showed that the catalytic activity toward glucose increased with the increase of OH- concentration up to the highest investigated concentration (1 M). The highest sensitivity and lowest detection limit were obtained for carbon paste electrodes modified with the equal amounts of carbon black and modifier. Under optimal conditions chronoamperometric measurements revealed that investigated electrode has two linear dynamic ranges. In the first range up to 1.5 mM sensitivity was 71.96 μAmM〈sup〉-1〈/sup〉 cm〈sup〉-2〈/sup〉 with LOD = 2.13 μM, while in the second range (2–10 mM) approx. two times lower sensitivity and higher LOD were found. The electrode exhibited excellent reproducibility, repeatability and long term stability. The high quality electrochemical performances together with low cost and easiness of synthesis makes cobalt oxide supported on pillared clay appealing sensing material for enzyme-free glucose detection.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Bolun Li, Qi Tian, Hongxin Su, Xingwei Wang, Tianen Wang, Dongzhi Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Portable humidity sensors fabricated in wearable devices have promising application in disease diagnostics and personal health monitoring. In this work, a capacitive humidity sensor based on indium oxide (In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉) nanocubes/graphene oxide (GO) nanosheets hybrid film was developed with Cu/Ni electrodes on an epoxy substrate. The In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/GO composite was analyzed through XRD, SEM, TEM and XPS for its composition, morphology and structure. The In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/GO film sensor was exposed to a wide range of relative humidity and its characteristics of capacitance performance with humidity were found to be better than humidity sensors based on pristine In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 or GO in terms of sensitivity, stability, response and recovery times. Meanwhile, a low-cost humidity and respiration monitoring system was developed on a print circuit board (PCB) based on STM32F405RGT6 microcontroller and Android Mobile APP. The curve of humidity and capacitance value can be shown on the smartphone, which can distinguish whether a person is breathing normally. The respiration detector designed holds great potential in the monitoring of asthma and irregular respiratory diseases due to its portability, instantaneity, accuracy and low power consumption.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Zhejia Gu, Simin Zhao, Gaolian Xu, Cang Chen, Yao Wang, Hongchen Gu, Yi Sun, Hong Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Multiplexed detection of nucleic acids is important for pathogen identification and disease diagnosis. Though real-time quantitative PCR allows for simultaneous amplification of different genes in a single test, the interferences between various primers inevitably cause difficulty in assay design, and pose limitation on multiplexing degree. Conventional solid-phase PCR (SP-PCR) on plenary microarrays can assess more targets than real-time quantitative PCR. However, they are suffering from low reaction efficiency, high background noise, and requiring special equipment and expertise for reliable analysis. Here, we addressed the challenges by performing multiplex PCR on thermostable, tailor-made host-guest encoded magnetic microspheres (Beads based PCR, BB-PCR), which were constructed by coupling magnetic host microspheres with fluorescent guest nanoparticles. As proof of concept, a 3-plex barcoded microbeads with high thermostability and low non-specific fluorescence absorption were selected as model BB-PCR carriers to amplify and detect three gene targets in Salmonella Enteritidis. After BB-PCR reaction, the barcoding and reporting signals were easily identified through flow cytometry. Attributed to the effective interactions between reagents and microspheres during PCR reaction, this method showed high sensitivity of 10 copies/reaction, which was comparable to that of liquid PCR. Thus, BB-PCR developed here allowed for simple, rapid, highly sensitive and high throughput detection of nucleic acid targets, which paves the way for routine multiplexed molecular diagnostics in clinical laboratories.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Xuerong Chen, Xiaoman He, Juan Gao, Jizhou Jiang, Xuanfeng Jiang, Can Wu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Carbon materials have received intensive attention due to their unique property in the field of electrochemical analysis. As transition metallic heteroatom and nitrogen-codoped carbon (M-N-C) materials commonly exhibit enhanced electrochemical activity for the tuned electronic structure, therefore, fabricating a novel structure of M-N-C material for electrochemical analysis is highly pursued. Herein, an 〈em〉in-situ〈/em〉 self-growth NaCl-templated strategy is proposed to fabricate three-dimensional porous Ni, N-codoped carbon material (3D Ni-N-C). The as-obtained 3D Ni-N-C demonstrates superior electrochemical performance toward glucose oxidation and sensing, and a highly sensitive and selective non-enzymatic glucose sensor is subsequently developed for human serums with a wide linear range of 0.001–1.20 mM, low detection limit of 0.15 μM, and high sensitivity of 1181.0 μA mM〈sup〉−1〈/sup〉 cm〈sup〉-2〈/sup〉. It is believed that the unique structural properties of 3D Ni-N-C (abundant N-doped and Ni-N coordinated active sites, large surface area, open micro-porous structure) are conducive to the formation and exposure of highly catalytic centers and improvement of electron-transfer rate.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092540051931144X-ga1.jpg" width="205" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 11 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Katarzyna Smolinska-Kempisty, Antonio Guerreiro, Joanna Czulak, Sergey Piletsky〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The solid-phase imprinting method was used to prepare particles imprinted against glycated haemoglobin by using the whole protein as a template. Obtained MIPs were then treated through a negative selection process to obtain high affinity MIPs able to recognize glycated haemoglobin but without any cross-reactivity towards non-glycated haemoglobin. Both, bulk and selected particles were tested in competitive 〈em〉pseudo-〈/em〉ELISA assays with haemoglobin and glycated haemoglobin as free targets. In both cases, a linear response was observed from 10〈sup〉-3〈/sup〉 nM to 1 nM. After negative selection, MIPs showed no response to non-glycated haemoglobin together with an improved of the linear range of the assay. It also allowed quantification of glycated haemoglobin in human serum with recoveries above 95 %.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Wei Liu, Yuelin Xie, Tingxuan Chen, Qixiao Lu, Shafiq Ur Rehman, Ling Zhu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Here, we demonstrate a facile design and simple fabrication of acetone gas sensors based on one-dimensional (1D) porous platinum (Pt)-doped In2O3 nanofiber structure. Be first to try to immerse electrospun polystyrene (PS) nanofibers (NFs) into a precursor solution followed by an annealing process, the as-prepared composite NFs can readily turn into Pt-In2O3 porous NFs. The obtained Pt-In2O3 porous NFs exhibit the mesoporous size of 4–6 nm and high specific surface area of 212.3 m2 g-1. We observed that the spillover effect of Pt nanoparticles and the large-surface-area of the porous structure can effectively enhance catalytic sensing response to acetone with a lower limit of 10 part-per-billion (ppb) at a low working temperature of 180 °C. More importantly, the proposed NFs-based sensor shows rapid response and recovery time (6/9 s), higher selectivity toward acetone against other interfering gases, reversibility and time stability (50 days) compared to its counterparts. In addition, the proposed sensor shows a fast response and recovery time, maintaining 70% of the initial response even in 85% relative humidity (RH) environment. These results demonstrate the potential feasibility that the Pt-In2O3 porous NFs act as a promising sensing platform for monitoring acetone at ppb levels in human breath.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310706-ga1.jpg" width="462" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Mrinmoy Maiti, Vishnu Priya Murali, Deepika Selvakumar, Arup Podder, Kaustabh Kumar Maiti, Sankarprasad Bhuniya〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein we describe the NADH tracking ability of “kick-on” self-immolative fluorescent probe (P〈sub〉NADH〈/sub〉) in live cells. The probe (〈strong〉P〈sub〉NADH〈/sub〉〈/strong〉) showed selective fluorescence emission at 552 nm in the presence of NADH upon excitation at 510 nm. The fluorescence intensity of probe 〈strong〉P〈sub〉NADH〈/sub〉〈/strong〉was ˜10-fold increased in the presence of 80 equivalents (400 μM) of NADH in PBS buffer at physiological condition. The probe 〈strong〉P〈sub〉NADH〈/sub〉〈/strong〉 is highly chemoselective toward NADH over the other competitive analytes. The probe 〈strong〉P〈sub〉NADH〈/sub〉〈/strong〉 has provided information of NADH in cancer cells such as HeLa, MDA-MB 231, and human normal fibroblast WI-38 cells. The biocompatible probe 〈strong〉P〈sub〉NADH〈/sub〉〈/strong〉 visualized dynamic changes of NADH attributed to the fluctuation of the specific substrates such as glucose, pyruvate and lactate in the glycolysis pathway. The first time we noticed that the extent of NADH-expression is decreased with upregulation of GSH in the live cells. The report on persistent crosstalk between NADH with redox regulator GSH motivate to search an antagonist for diseases associated with oxidative stress.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311633-ga1.jpg" width="289" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Sandeep Choudhary, Bhavana Joshi, Gaurav Pandey, Abhijeet Joshi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Milk is a high nutrient value food substance consumed by the entire population in several forms. Spoilage and degradation of milk and its products during transportation, processing and packaging are some of the major losses by dairy industries. The change in milk pH with time is an indicating factor of milk degradation. This research reports a rapid, sensitive and facile fluorescence-based technique to study the time-based milk degradation at room temperature. Fluorescein isothiocyanate (FITC)/ FITC-dextran (FITC-dex) and Tris (2, 2′-bipyridyl) dichloro ruthenium (II) hexahydrate (Ru-bpy) were used to develop solution phase and immobilized phase pH sensors. Immobilized phase sensors constituted of alginate microspheres (5 ± 3 μm) produced using an air driven atomizer. The pH sensor works in a linear range of 3–8 pH units with a quick response time of 30 s. The percentage recovery of the system lay in the range of 89.23%–101.28% for detection of milk pH. Accurate detection was possible during entire shelf life of milk (˜24 h) and Inter-sample and inter-day reproducibility was checked over 10 days duration. The results clearly indicate that both single and dual fluorophore-based assay in solution phase and immobilized phases can predict milk pH with good accuracy.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉pH sensors for milk quality and shelf life determination.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311244-ga1.jpg" width="360" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Sumit Kumar Das, Kunal Pal, Tara Shankar Bhattacharya, Parimal Karmakar, Joydeep Chowdhury〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper reports fabrication of efficient and reproducible Surface Enhance Raman Scattering active substrate through integration of self-assembly and Langmuir-Blodgett technique for the detection of normal and cancerous cell lines associated with prostate and breast cancers. Morphology of the substrate has been visualized using FESEM and AFM images. 〈em〉In vitro〈/em〉 cytotoxicity test was performed to check the biocompatibility of the substrate. SERS sensing ability of the substrate has been tested with the probe 4-Mercaptopyridine molecule. The as-prepared substrate has been employed for the first time to detect normal and cancerous cell lines linked with prostate and breast cancers. Multivariate statistical approaches like principal component analysis (PCA) and loading spectra were further explored for segregation and identification of the cancer cells from their normal counterparts. Intriguingly, the peak positions of the loading spectra nearly correspond to the difference SERS spectra between the normal and cancerous cell lines of prostate and breast cancers. To our knowledge, such one to one correspondence between the peak positions of loading and differences in the SERS spectra has been noticed for the first time and can act as a diagnostic platform to identify the biomarkers for cancerous cell lines in the molecular scale.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092540051931161X-ga1.jpg" width="415" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): S. Veerabuthiran, A.K. Razdan, M.K. Jindal, Girraj Prasad〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A tunable mid-infrared differential absorption lidar (DIAL) mounted on a mobile platform has been built for long range remote detection of thiodiglycol (TDG) vapor plumes. The IR spectra of TDG have been analyzed from available spectroscopy database and from the laboratory measurement. Based on the analysis, laser wavelengths at 3.190 and 3.300 μm have been selected as λ〈sub〉on〈/sub〉 (strong absorption) and λ〈sub〉off〈/sub〉 (weak absorption) in the measurements. The influence of interfering molecules at these wavelengths has been also studied. The lidar return signal and sensitivity of the system have been numerically simulated based on the system parameters. The experimental DIAL system has been built using an optical parametric oscillator (OPO) based tunable laser operating in the wavelength band 3.0–3.45 μm as a transmitter and Cassegrain telescope having 200 mm diameter mirror integrated with thermoelectric cooled mercury cadmium telluride (MCT) detector as a receiver. The trans-receiver system is mounted on a pan-tilt that enables the aerial scanning operations. The lidar subsystems have been assembled and integrated on a mobile platform for conducting field experiments. An initial field testing of the system has been carried out at a remote site using the enclosed chamber containing the TDG vapor. The chamber was erected at a distance of about 950 m acted as a topographic target that reflected the laser radiation. The differential absorption signal in terms of signal ratio has been monitored continuously in real time during the trial period. The varying column content ranging from 10 to 200 ppm × m under dynamic atmospheric conditions has been calculated and discussed in this paper.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Kanishk Singh, Bih-Show Lou, Jim-Long Her, See-Tong Pang, Tung-Ming Pan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we fabricated a sol-gel derived RuO〈sub〉x〈/sub〉, with low-temperature thermal oxidation, on polyethylene terephthalate (PET) flexible based extended-gate field-effect transistor (EGFET) as a pH sensor for the assessment of glucose for the first time. Structural identification, surface morphology, and film composition of the sensing membrane were investigated by X-ray diffraction, atomic force microscopy, and X-ray photoelectron microscopy, respectively. The RuO〈sub〉x〈/sub〉 on PET based EGFET sensor exhibited a pH sensitivity of 65.11 mV/pH in the wide range of pH 2–12 with an excellent linearity of 0.999. This sensor showed good reversibility in terms of a lower hysteresis voltage of ∼1 mV and a better stability for 12 h named as drift rate ∼2.08 mV/h. The RuO〈sub〉x〈/sub〉-based EGFET sensor also demonstrated a high selective response towards H〈sup〉+〈/sup〉. In addition, the pH performace of this RuOx EGFET flexible sensor kept unchanged after 500 repeated bending cycles. Subsequently, the RuO〈sub〉x〈/sub〉 on PET based EGFET was functionalized by 4-carboxyphenyl boronic acid (4-CPBA), which is a synthetic receptor for covalent attachment of glucose on the sensing surface. The sensitivity of glucose was 6.89 mV/mM with the linearity of 0.993 within the glucose concentration from 1 to 8 mM. The concentration of serum glucose measured by our 4-CPBA functionalized RuO〈sub〉x〈/sub〉 EGFET biosensor is comparable to that determined by commercial blood glucose monitoring system. In addition, this RuO〈sub〉x〈/sub〉 EGFET biosensor exhibited an elevated reference voltage shift response to glucose compared with other saccharides (e.g. fructose, sucrose and mannose).〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Yonghao Wang, Dengwang Luo, Yao Fang, Wanhao Wu, Yongjing Wang, Yaokun Xia, Fang Wu, Chunyan Li, Jianming Lan, Jinghua Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Exosomes may be used as a crucial medium for the early diagnosis and potential therapy of tumors because of containing a variety of biological information. Therefore, the accurate quantitative analysis of exosomes is especially important in the biomedical field. Herein, we proposed a washing-free aptasensor based on luminescence resonance energy transfer (LRET) between rare-earth doped upconversion nanoparticles (UCNPs) donor and tetramethyl rhodamine (TAMRA) acceptor for highly sensitive detection of exosomes. Therein, the combination of UCNPs and TAMRA can be achieved through the coupling of aptamers to the epithelial cell adhesion molecule (EpCAM), the highly expressed surface proteins of the exosomes. Therefore, when the system of UCNPs-TAMRA in the presence of exosomes is excited by near-infrared light at 980 nm, TAMRA emits yellow fluorescence at 585 nm due to LRET. As a result, the fluorescence intensity at 585 nm is linearly correlated to the concentration of exosomes, which is available for the detection and quantification of exosomes. Under optimal conditions, the proposed approach can reach a low limit of detection (LOD) of 80 particles/μL, and effectively reduce the background signal by using UCNPs as an energy donor. Moreover, this proposed aptasensor can be universally applied to the detection of other targets by strictly screening the aptamers.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A washing-free aptasensor based on LRET between upconversion nanoparticles (UCNPs) donor and tetramethyl rhodamine (TAMRA) acceptor for highly sensitive detection of exosomes was proposed, which could significantly simplify the testing process and shorten the detection time.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310998-ga1.jpg" width="340" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Javad Yoosefian, Naader Alizadeh〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Since the simple and accurate quantification of 2,4,6-trinitrotoluene (TNT) traces is still a challenge for analytical chemists, we employed a recently developed crossed-beam photothermal lens spectrometer for highly sensitive and selective determination of TNT through a well-known Meisenheimer complexation with n-butylamine (nBA). The colorless solution of TNT in dimethyl sulfoxide (DMSO) was changed to deep-red after the addition of nBA. Hence, we used a 532 nm diode laser as excitation source in photothermal lens investigations. All the instrumental parameters and chemical conditions such as chopper frequency, sample flow velocity, amine concentration and etc. were optimized. Photothermal lens measurements yielded a linear signal dependence on TNT quantity from 5 to 100 nM. The limit of detection (LOD) was 1.6 nM (˜5 fmol). The method was successfully carried out for determination of the TNT vapor extracted into the 300 μL dimethyl sulfoxide (DMSO).〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310810-ga1.jpg" width="263" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Menghan Dun, Jianfeng Tan, Wenhu Tan, Meihui Tang, Xintang Huang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With the urgent need to improve societal security, semiconductor-based gas sensors have received substantial attention for their efficiency and accuracy in the detection of harmful gases. However, challenging existed to develop sensors that exhibit both high response and rapid response/recovery rates at room temperature. Herein, we present a simple and energy-efficient room-temperature in situ growth strategy to prepare CdS quantum dots supported by ultrathin porous nanosheets assembled into hollowed-out Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 microspheres (CdS QD/Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 HMSs). XRD, EDX, BET, SEM, TEM and HRTEM analysis confirmed that the interconnected CdS QDs (˜4.5 nm) were well dispersed on the ultrathin porous nanosheet of Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 HMSs. The fabricated CdS QD/Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 HMS sensor exhibited high response (12.7) and ultra-fast response/recovery rates (0.6/1.0 s) to 100 ppm H〈sub〉2〈/sub〉S at 25 °C, which is ascribed to high active quantum dots and hollowed-out nanostructure. In addition, the sensor exhibited a low detection limit (1–5 ppm), good reversibility and exceptional long-term stability. This work explores an efficient way to fabricate high-response and ultra-fast response/recovery room-temperature gas sensors by integrating quantum dots with hollowed-out nanostructures.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Li-Hong Ma, Hai-Bo Wang, Ting Zhang, Yang Xuan, Cheng Li, Wei Chen, Bo Liu, Yuan-Di Zhao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Liver cancer is one of the most common cancers in the world. The gene CYP1A1 is closely related to the occurrence of cancer, and the tumor marker alpha-fetoprotein (AFP) is also one of the important indicators for liver cancer screening. Therefore, detection of these two substances is of great significance. In this paper, a test strip biosensor capable of simultaneously detecting cancer susceptibility gene CYP1A1 and AFP has been established. There were two detection lines in the strip biosensor, one was used for qualitative detection of susceptible gene by base complementary pairing, and the other was used for semi-quantitative detection of AFP by antigen-antibody reaction. Finally, signal amplification was achieved by horseradish peroxidase catalyzing substrate 3-amino-9-ethylcarbazole. Results showed that under the optimized conditions, the strip biosensor had a good linear relationship (R〈sup〉2〈/sup〉 = 0.987) when AFP concentration was in the range of 20–250 ng/mL, and the other hundred times of proteins had no obvious interference to the detection, indicating that the method presented good selectivity. The detection of susceptibility gene CYP1A1 and AFP in real blood samples by the strip was in accordance the standard method, which showed that the method had good accuracy and could be used for qualitative judgment of SNP locus base type of susceptibility gene and semi-quantitative detection of tumor marker in real sample, so it had a good application potential.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Èric Navarrete, Carla Bittencourt, Xavier Noirfalise, Polona Umek, Ernesto González, Frank Güell, Eduard Llobet〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A two-step procedure was implemented to obtain tungsten oxide nanowires (WO〈sub〉3〈/sub〉) doped with cobalt oxide nanoparticles employing W(CO)〈sub〉6〈/sub〉 and the metal-organic precursor Co(acac)〈sub〉2〈/sub〉. In the first step, tungsten oxide nanowires were grown at 400 °C using an aerosol assisted chemical vapor deposition system (AA-CVD) and subsequently annealed at 500 ºC for 2 h in dry air. Then, cobalt oxide loading (at different dose levels) of the nanowires was performed via a second AA-CVD process. These hybrid nanomaterials were grown on top of commercial alumina substrates that comprised interdigitated electrodes and a heating element. The response of these nanomaterials toward H〈sub〉2〈/sub〉S, ethanol H〈sub〉2〈/sub〉 and ammonia is investigated and discussed. Co-loaded tungsten oxide is well suited for detecting ammonia under dry conditions and hydrogen sulfide in humid environments.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310676-ga1.jpg" width="412" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Chu Hongxia, Hu Ji, Li Zaijun, Li Ruiyi, Yang Yongqiang, Sun Xiulan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Glutamic acid-functionalized graphene quantum dots (Glu-GQD) was prepared by pyrolysis of citric acid and glutamic acid and used as reducing agent and stabilizer to produce Glu-GQD/Au in the presence of tannic acid. The resulting Glu-GQD/Au was covalently connected with aptamer (Apt) of acetamiprid to obtain one redox probe with catalyst. The study shows that Glu-GQD/Au offers nanostar-like structure with average particle size of 102.5 nm, composing of several nanometer-sized gold nanocrystals with the rich of sharp edges and corners. The unique structure makes gold nanostars good electrocatalytic activity, which was further improved by combination with Glu-GQD. In the redox probe, Glu-GQD can carry out reversible redox reaction on the electrode surface due to its high electroactivity. Gold nanostars in-situ catalyzes redox reactions of Glu-GQD and leads to an improved electrochemical behavior. Aptamer can specifically bind with acetamiprid and produce sensitive and selective electrochemical response. The electrochemical aptasensor based on Glu-GQD/Au-Apt/graphene aerogel exhibits ultrahigh sensitivity and selectivity for detection of acetamiprid. The differential pulse voltammetric signal linearly decreases with increasing acetamiprid concentration in the range from 1.0 fM to 1 × 10〈sup〉5〈/sup〉 fM with detection limit of 0.37 fM (S/N = 3). The aptasensor has been successfully applied in electrochemical detection of acetamiprid in vegetables.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉The study reported one concept for fabrication of glutamic acid functionalized graphene quantum dot-gold hybrid. The hybrid exhibits nanostar-like structure, excellent redox behaviors and was successfully applied in fabrication of electrochemical aptasensor for detection of acetamiprid with ultrahigh sensitivity and selectivity.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310652-ga1.jpg" width="481" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Ting Huang, Jingjing Yang, Wanqing Zhou, Xinli Liu, Yongchun Pan, Yujun Song〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rapid and accurate detection of bacteria in urine is the key to improving the diagnostic efficiency of urinary tract infections. In this work, a microfluidic device was developed for visually quantifying pathogenic bacteria in urine without any external equipment. This pioneering strategy has high sensitivity, selectivity and accuracy for rapid detection of 〈em〉Escherichia coli〈/em〉 and 〈em〉Staphylococcus aureus〈/em〉 simultaneously. It not only shortens the entire test time to 1.5 h, but also successfully reduces the detection limit to 1 CFU/mL, which significantly improves the early diagnosis rate of bacterial infections. Due to the strong affinity of aptamers to target bacteria and the amplification of signals by platinum nanoparticle probes (Pt NP probes) with high catalytic activity, the sensitivity of the device has reached 1 CFU/mL. Moreover, the detection results of UTIs in clinical specimens were consistent with the gold standard, which not only verifies the good accuracy and reliability of the method in such a complex liquid environment, but also implies that the application of the device is paving a new path for biomarker detection and disease diagnosis.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310846-ga1.jpg" width="204" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Zhipeng Zhang, Jiayu Feng, Pengcheng Huang, Sha Li, Fang-Ying Wu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report a new fluorescent nanoprobe simply constructed by the surface modification of positively charged polyethylenimine (PEI)-coated gold nanoclusters (AuNCs) with 8-hydroxyquinoline-5-sulfonate (8Q5S) through electrostatic interaction. This nanoprobe showed the intrinsic emission of AuNCs at 650 nm and a weak emission at 490 nm from 8Q5S. Based on chelation-enhanced fluorescence of 8Q5S induced by its specific and high affinity for phosphate upon binding Mg〈sup〉2+〈/sup〉 and the stable fluorescence of AuNCs as the reference, this nanoprobe was demonstrated to exhibit highly sensitive, selective, and reliable detection of phosphate in the linear range from 0 to 50 μM with a low detection limit of 0.14 μM. Furthermore, the presented ratiometric fluorescent sensor was successfully employed for accurate quantitation of phosphate in complex human serum samples with satisfactory results.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310901-ga1.jpg" width="321" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Qingyun Li, Zhencao Wang, Meng Zhao, Yanping Hong, Qiwei Jin, Shenyan Yao, Cailin Zheng, Yun-Yun Quan, Xiaoxia Ye, Zu-Sheng Huang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrogen sulfide (H〈sub〉2〈/sub〉S) plays a significant role in many pathological and physiological processes in living system. It is of great importance to develop effective fluorescent probes for H〈sub〉2〈/sub〉S detection with good sensitivity and high selectivity. In this work, we developed a new near-infrared (NIR) fluorescent probe 〈strong〉DBT〈/strong〉 for H〈sub〉2〈/sub〉S detection with fluorescence turn-on performance. For probe 〈strong〉DBT〈/strong〉, triphenylamine combined with BODIPY is used as the fluorophore and 2, 4-dinitrophenylsulfonyl group is acted as the reaction site. The results show that 〈strong〉DBT〈/strong〉 exhibits excellent sensing characters toward H〈sub〉2〈/sub〉S with rapid response (within 150 s), excellent sensitivity (detection limit of 6.74 nM) and good selectivity. Importantly, this probe is also successfully applied in the fluorescent imaging of endogenous H〈sub〉2〈/sub〉S in HCT116 cells. The outcomes indicate that the probe 〈strong〉DBT〈/strong〉 is a valuable tool for H〈sub〉2〈/sub〉S detection in solution and living cells.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310974-ga1.jpg" width="227" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Shuyao Wu, Jinyu Hao, Shaojun Yang, Ying Sun, Yulu Wang, Wei Zhang, Hui Mao, Xi-Ming Song〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel electrochemical platform composed of water soluble polyethylene imine-reduced graphene oxide (PEI-rGO) composites and cholesterol oxidase (ChOx) based on layer-by-layer (LBL) technique has been triumphantly developed. The PEI-rGO composites could effectively improve the electron transfer ability between the assembled enzyme and the surface of electrode. Furthermore, LBL technique could immobilize more enzyme under mild conditions, which was benefit to keep the bioactivity of redox enzyme. TEM, UV–vis and FT-IR showed that the PEI-rGO composites behaved as individual nanosheet structure and were successfully prepared. The self-assembly process of (ChOx/PEI-rGO)〈sub〉n〈/sub〉 film was monitored by UV–vis spectroscopy, demonstrating that the ChOx had been immobilized orderly without denaturation. Owing to the good conductivity of the PEI-rGO composites, the electron transfer ability of the immobilized ChOx was greatly improved on glassy carbon electrode (GCE). The PEI/(ChOx/PEI-rGO)〈sub〉3〈/sub〉/GCE showed excellent electrochemical performances toward the detection of cholesterol. Under optimized conditions, the fabricated electrode exhibited a wide linear range in the cholesterol concentration from 0.10 × 10〈sup〉−6〈/sup〉 to 9.331 × 10〈sup〉−3〈/sup〉 mol L〈sup〉−1〈/sup〉 with a detection limit of 0.021 μmol L〈sup〉−1〈/sup〉 estimated at a signal-to-noise ratio of 3. The apparent Michaelis-Menten constant (〈em〉K〈sub〉m〈/sub〉〈/em〉) was 0.0431 mmol L〈sup〉−1〈/sup〉. This result indicated that a good affinity between the immobilized ChOx and the cholesterol. Meanwhile, the biosensor presented good stability, reproducibility and anti-interference ability with good recoveries for real sample detection.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Lavanya L. Mittapelli, Ganesh N. Nawale, Sachin P. Gholap, Oommen P. Varghese, Kiran R. Gore〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrogen sulphide is a gaseous neurotransmitter responsible for neuronal function and controls vast range of physiological functions. Herein, we report the synthesis and evaluation of novel Green Fluorescent Protein (GFP) chromophore analog, acryloyl-4-(p-hydroxybenzylidene)-5-imidazolidinone (〈strong〉AHBI〈/strong〉) for turn-on fluorescent detection of H〈sub〉2〈/sub〉S over wide range of anions and various biologically important competitive thiols. 〈strong〉AHBI〈/strong〉 probe exhibited high selectivity and sensitivity, high fluorescence stability, large stokes shift and lower detection limit (15.85 ppb) for H〈sub〉2〈/sub〉S in complete water medium. Cell imaging studies in human colon cancer cells (HCT116) and normal human dermal fibroblasts (HDF) confirmed the compatibility and versatility of 〈strong〉AHBI〈/strong〉 probe at micromolar level. Overall, we believe the 〈strong〉AHBI〈/strong〉, as an optical probe will be useful to investigate the role of H〈sub〉2〈/sub〉S in various physiological processes, regulation of cancer cell growth, and in pathogenic events.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310743-ga1.jpg" width="274" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Dan-bi Myung, Saddam Hussain, Soo-Young Park〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ion and humidity sensor array films have been developed using an interpenetrating polymeric network (IPN) of photonic networked cholesteric liquid crystals (CLCs) intertwined with network-structured poly(acrylic acid). Selective curing of a photonic CLC network film infiltrated with an acrylic acid/tri(propylene glycol) diacrylate mixture produced an array film of dots with photonic IPN structures on a simple photonic CLC background. Water isolation by individual hydrophilic dots against a hydrophobic background allowed testing of small sample amounts. Subsequent acetone/KOH treatments of the IPN film (IPN〈sub〉acetone/KOH〈/sub〉 film) prevented hydrogen bonding between carboxylic groups, maximized swelling of the film with water, and increased the speed of photonic color change. A full range of reflected colors, i.e., blue (dry) to red (humid), allows this film to act as an optical humidity sensor. The replacement of K〈sup〉+〈/sup〉 with divalent ions that bridge the carboxylic groups prevented film swelling. Given that the photonic band gap wavelength is inversely proportional to the CaCl〈sub〉2〈/sub〉 concentration, the amount of Ca〈sup〉2+〈/sup〉 can be determined from the reflected color by the naked eye. This cost-effective, convenient IPN〈sub〉acetone/KOH〈/sub〉 film has been successfully applied as a biosensor for detecting Ca〈sup〉2+〈/sup〉 in human blood serum and saliva and as an anti-counterfeiting label that reveals a colorful image under humid conditions.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310937-ga1.jpg" width="463" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Yifan Jin, Jingyi Wang, Yuanyu Wu, Xinrui Fu, Wei Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A smart DNA tweezer was constructed for universal proximity assay and logic building. In this tweezer, the set strand was designed as recognition module, and the ends of two motifs were ingeniously designed as toehold domain (TD) and branch migration domain (BMD). As the recognition of set strand and target, the set strand could be dismantled from the tweezer, resulting in a proximity binding of TD and BMD. Then, the proximal TD and BMD could initiate the dynamic assembly of two complementary hairpins, yeilding a long double-stranded polymer with multiple G-quadruplexes. By inserting fluorescent dye, enhanced fluorescent response could be observed. Universal and sensitive assay of miRNA and thrombin were achieved by altering the sequence of set strand. The corresponding detection limits were 9.4 fM and 0.35 pM. Moreover, quantitative analysis of miRNA in clinical serum sample was also performed, suggesting the feasibility of this proximity assay in clinical application. What’s more, based on the proposed DNA tweezer, a Boolean logic operation platform was fabricated, and systematic logic operations were also achieved. Therefore, this work provided a reliable strategy for universal proximity assay and logic operation, which could be further used in biomedical research and clinical diagnosis.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Min Zhang, Chaoqi Wang, Zeyuan Zhang, Jing Ye, Piaopiao Fang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel carbon paste electrode (CPE) modified with three-dimensional graphene (3D-GN) has been developed for sensitive, selective and rapid determination of chloride ion (Cl〈sup〉−〈/sup〉) for the first time. Compared with bare carbon paste electrode (CPE) and graphene nanosheets modified CPE (GN/CPE), the peak current of Cl〈sup〉−〈/sup〉 on 3D-GN/CPE was sharply increased. The sensitivity achieved 0.156 μA mM〈sup〉−1〈/sup〉 cm〈sup〉−2〈/sup〉, which was nearly 1500-fold than bare CPE. The response time was less than 30 s and steady till 120 s. Using differential pulse voltammetry (DPV), the peak current at around 0.05 V was linear with the concentration of Cl〈sup〉−〈/sup〉 from 0.5 to 1000 mM, and the limit of detection was calculated to be 0.2 mM (S/N = 3). After 100 test using a same electrode, the peak current of Cl〈sup〉−〈/sup〉 was still 90–110% of the first time, showing the outstanding reusability. The proposed sensor was successfully applied in real water samples.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311505-ga1.jpg" width="286" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Mohammad Bagher Gholivand, Elahe Ahmadi, Maryamosadat Mavaei〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a novel electrochemical sensor for the detection of cisplatin, an anti-cancer drug, was introduced. Graphene quantum dots (GQDs) modified with thionine were synthesised for the first time and immobilised as a suitable nanostructure modifier on the nano-porous glassy carbon electrode (npGCE) for selective and sensitive determination of cisplatin. The morphology of the GQDs-thio/npGCE surface was specified by electrochemical impedance spectroscopy (EIS) and the field-emission scanning electron microscopy (FE-SEM). The linear range of anodic stripping response to drug concentration was 0.2–110 μM with the detection limit (S/N = 3) of 90 nM, compared with previous studies, the lowest LOD for cisplatin has been obtained. The proposed electrode was sensitive, selective, and its applicability was tested by analysing cisplatin in biological fluids, including blood serum and urine samples. The recovery experiments were performed with both real samples spiked with the drug at different concentration levels and resulted in almost quantitative recoveries (between 98 and 104%). Fluorescence spectroscopic and electrochemical methods examined the interaction of cisplatin-thionine.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311748-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Július Gajdár, Jiří Barek, Jan Fischer〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study presents an application of a non-toxic mercury meniscus modified silver solid amalgam electrode as a reliable, user-friendly and sensitive sensor for the determination of herbicide difenzoquat as a model pollutant in micro volumes of samples. Difenzoquat gave one cathodic peak at around –1.4 V (vs. Ag/AgCl/3 mol L〈sup〉–1〈/sup〉 KCl reference electrode) independent on pH (in the range 8–12). Sharp maxima greatly influenced the peak of the analyte and they were eliminated by the addition of gelatine as a surface-active compound. The optimal supporting electrolyte was found to be Britton-Robinson (BR) buffer with pH 12. Determination of the analyte in the 10 μL volume was carried out in a newly developed simple microcell with the amalgam working electrode. A procedure for fast and reliable removal of dissolved oxygen was used. Difenzoquat was therefore successfully determined by differential pulse voltammetry in BR buffer pH 12 and in model river water samples with addition of gelatine with limits of quantification 0.41 and 0.45 μmol L〈sup〉–1〈/sup〉, respectively. It was proved that this sensor can be directly used for monitoring of pollutants in volumes of tens of microliters of various samples with similar parameters as the determination in larger volumes.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Francisco Pena-Pereira, Nerea Capón, Inmaculada de la Calle, Isela Lavilla, Carlos Bendicho〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Poly(vinylpyrrolidone)-supported copper nanoclusters (CuNCs) are employed in the present work as luminescent probes for iodide determination in water samples. The method involves the combination of two miniaturized analytical systems, namely nanoparticle-enhanced liquid-phase microextraction and microvolume fluorospectrometry. The proposed method is based on the 〈em〉in situ〈/em〉 generation of iodine and trapping of the evolved volatile into a CuNCs-containing aqueous microdrop, thus leading to fluorescence quenching. The fluorescence quenching mechanism for iodine sensing can be presumably ascribed to a ‘sphere of action’ static quenching model. Instrumental conditions, as well as a number of experimental parameters affecting extractant phase composition, iodine generation conditions and mass transfer of the volatile, have been evaluated. An outstanding enrichment factor of 〈em〉ca.〈/em〉 1100 was achieved under optimal conditions, yielding limits of detection and quantification of 1.0 ng/mL and 3.4 ng/mL, respectively. The repeatability, expressed as relative standard deviation, was found to be 7.4% (N = 7). The method was validated against a certified reference material and successfully applied to the analysis of different water samples. Furthermore, paper-based analytical devices containing CuNCs have been evaluated for the non-instrumental sensing of iodine generated 〈em〉in situ〈/em〉, showing promise as an inexpensive and portable alternative for iodide determination.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311785-ga1.jpg" width="369" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): V. Serafín, B. Arévalo, G. Martínez-García, J. Aznar-Poveda, J.A. Lopez-Pastor, J.F. Beltrán-Sánchez, A.J. Garcia-Sanchez, J. Garcia-Haro, S. Campuzano, P. Yáñez-Sedeño, J.M. Pingarrón〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This work describes a new electroanalytical device for the simultaneous and reliable determination of two fertility relevant hormones (luteinizing hormone, LH, and progesterone, P4) in saliva. The device is constructed using a custom designed and field-portable potentiostat where dual disposable immunosensing platform are connected. The immunosensors are based on sandwich-type and competitive immunoassays implemented onto magnetic microbeads (MBs) functionalized with Neutravidin and Protein G for the determination of LH and P4, respectively. Amperometric detection performed at −0.20 V vs the Ag pseudo-reference electrode using the H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉/hydroquinone (HQ) system was employed as the transduction technique after placing the MBs with immunocomplexes for each target hormone on the appropriate working electrode of screen-printed dual carbon electrodes (SPdCEs). The method exhibits high sensitivity and selectivity for the target hormones providing detection limits of 1.7 pg mL〈sup〉−1〈/sup〉 and 0.10 mIU mL〈sup〉−1〈/sup〉 for P4 and LH, respectively, with a 1 h test time. The applicability of the method was confirmed by determining both hormones in saliva samples from different volunteers providing results comparable to those obtained using amperometric transduction with a commercial potentiostat and with ELISA methodologies involving the same immunoreagents for each target hormone.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Simultaneous determination of fertility hormones in saliva using disposable immunosensing platforms and a custom designed field-portable dual potentiostat.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311335-ga1.jpg" width="450" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Gayan Premaratne, Asantha C. Dharmaratne, Zainab H. Al Mubarak, Farshid Mohammadparast, Marimuthu Andiappan, Sadagopan Krishnan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nano-biosensors that are not only sensitive and selective, but also enable multiplex detection of ultra-low levels of both large and small biomolecules in clinical sample matrices are essential for 〈em〉in vitro〈/em〉 diagnostics. We present herein a multiplex surface plasmon microarray design that employs citrate-stabilized Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@Au core/shell nanoparticles (NPs) as the plasmon signal amplification label for combined detection of serum proteins and nucleotide markers. The multiplex sensing is demonstrated using two interleukins (IL-6 and IL-8) and two microRNAs (miRNA-21 and miRNA-155) in 10% serum, which is clinically relevant than simple buffer solution based biosensors. We observed that the surface plasmon signal change for larger proteins even at higher concentrations was less than the relatively smaller miRNA molecules. We draw two conclusions from this result: 〈strong〉(i)〈/strong〉 the number of selectively bound analytes onto the sensor (i.e., antigen for an antibody or miRNA for a capture nucleotide) influences the signal change, and 〈strong〉(ii)〈/strong〉 the extent of interaction of the detection probe carrying core/shell NP labels with the sensor surface plasmons influences the amount of signal change. Results indicate that both factors, (i) and (ii), are greater for small oligonucleotide hybridization assembly than a large sandwich protein immunoassembly. The core/shell NPs offered several fold enhanced sensitivity and wider dynamic range of detection over assays without using them. With recently growing attention on 〈em〉in vitro〈/em〉 diagnostics for painless/minimally-invasive detection of diseases and abnormalities, findings presented herein are important for designing novel multiplex biosensors for real sample analysis in complex matrices.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311554-ga1.jpg" width="230" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Anh Duy Duong Le, Juil Hwang, Mohammad Yusuf, Kang Hyun Park, Sungkyun Park, Jaeyong Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A polymer-overlaid two-mode microfiber knot resonator (TMM-KR) was designed to measure relative humidity (RH) and temperature simultaneously in a living condition. The device is composed of two main optical features: two-mode microfiber (TMM, slow-varying term) and two-mode knot resonator (TM〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉KR, fast-varying term). After fabricating a TMM by non-adiabatically tapering a conventional single mode fiber (SMF), we designed C-rGO-overlaid TMM as a polymer-overlaid optical sensor to evaluate the response and recovery times. The effective group refractive index between fundamental and cladding modes, HE〈sub〉11〈/sub〉 and HE〈sub〉12〈/sub〉, respectively, of the TMM-KR reduced to nearly zero by optimizing the waist diameter of the optical microfiber, and the sensitivities of the proposed sensor remarkably enhanced to 0.603 nm/%, and -0.79 nm/〈sup〉o〈/sup〉C, for RH and temperature, respectively. Our calculated and experimental results demonstrated that the proposed micro-structure of the C-rGO-overlaid TMM-KR will provide optical properties that can be applied for practical use of environment sensing.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Highlights〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310408-ga1.jpg" width="244" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Yonghai Song, Jiajia Han, Lijuan Xu, Longfei Miao, Canwei Peng, Li Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Dopamine (DA) is a nerve-transducing chemical that helps cells transmit pulses. Too high or too low concentration of DA is detrimental to human health. Therefore, finding a fast, efficient and sensitive method for detecting DA is of great significance. Here, a DA-imprinted chitosan (CS) film/ZnO nanoparticles (NPs)@carbon (C)/three-dimensional kenaf stem-derived macroporous carbon (3D-KSC) was prepared for electrochemical detection of DA. The DA-imprinted CS film/ZnO NPs @C/3D-KSC was prepared by growing zeolite imidazole framework-8 (ZIF-8) on 3D-KSC, carbonizing under N〈sub〉2〈/sub〉 atmosphere, electrodepositing AA-CS on ZnO NPs@C/3D-KSC and eluting template AA molecules. The results showed that ZIF-8 derived porous ZnO NPs@C nanospheres were arranged evenly on 3D-KSC surface to form a monolayer. The diameter of nanospheres was approximately 500–600 nm, and the nanospheres were composed of ZnO NPs embedded in porous carbon. A layer of CS with DA-imprinted pores was covered on the ZnO NPs@C nanospheres, so the DA-imprinted CS film/ZnO NPs@C/3D-KSC integrated electrode exhibited better selectivity for DA detection. The linear range was 0.12 nM-152 μM, the detection limit was 0.039 nM, and the sensitivity was 757 μA mM〈sup〉−1〈/sup〉 cm〈sup〉-2〈/sup〉. The DA-imprinted CS film/ZnO NPs@C/3D-KSC integrated electrode also showed higher stability.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311487-ga1.jpg" width="411" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): S. Sajed, F. Arefi, M. Kolahdouz, M.A. Sadeghi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Detection of various contaminations in drinking water such as heavy metal ions and toxic chemicals is costly, time-consuming and requires an accompanying computing device to capture and analyze the data. Hence, there is an extensive need for a rapid, user-friendly, cost-effective, sensitive and ubiquitous detection technique. Smartphones are an effective means to measure, analyze and share the results. In this work, a gadget was designed and printed using a lightweight 3D material, which can be attached to any smartphone and integrated with optical components. A full color TFT LCD display was used as the uniform source of any color of light. Aptamer conjugated gold nanoparticles were employed to determine the concentration of Hg〈sup〉2+〈/sup〉 as the basis of a colorimetric sensor. Interaction between the aptamer and the analytes leads to a color change in the solution due to aggregation of gold nanoparticles. For the corresponding color change detection, a novel image processing protocol using RGB value was introduced for each captured image. Multiple linear regression analysis was also exploited to achieve a better sensor response model. Light source enhancement, colorimetry at more points of visible spectrum (470, 540, 640 nm) and a powerful post process technique including machine learning made it possible to obtain an excellent level of sensitivity (1 nM–0.2 ppb).〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311414-ga1.jpg" width="212" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Xiaopan Song, Li Li, Xin Chen, Qi Xu, Bao Song, Ziyu Pan, Yining Liu, Fangying Juan, Fan Xu, Bingqiang Cao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Chemiresistive gas sensor with high sensitivity, selectivity and fast response for specific target gas has many applications from environmental monitor to internet of things. Herein, a highly sensitive and selective nanostructured triethylamine (TEA) gas sensor is fabricated successfully by designing semiconductor heterostructures consisting of ZnO nanorods and α-Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanoparticles. ZnO nanorods grow directly on flat Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 electrodes and α-Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanoparticles are deposited onto ZnO nanorods by pulsed laser deposition (PLD). Such α-Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/ZnO sensor has larger specific surface area (20.79 m〈sup〉2〈/sup〉/g), adsorbs more oxygen ions and exhibits higher response (63 to 50 ppm TEA), lower detection concentration (˜1 ppm), and shorter response time (4 s), which are all much better than the controlled ZnO nanorods sensor. Besides the interface depletion layer at the α-Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/ZnO interface, we find that the surface depletion layer due to oxygen absorption is also very important for the sensor performance. Moreover, more surface adsorbed oxygen in the α-Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/ZnO sensor is proved by both XPS analysis and density functional theory (DFT) simulation, which highlights the significance of gas sensing mechanism study for such composite heterojunction structure.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311165-ga1.jpg" width="280" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Huiling Tai, Zaihua Duan, Zaizhou He, Xian Li, Jianglong Xu, Bohao Liu, Yadong Jiang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a novel 2D material, Ti〈sub〉3〈/sub〉C〈sub〉2〈/sub〉T〈em〉〈sub〉x〈/sub〉〈/em〉 has been proved to be promising in the field of room temperature ammonia (NH〈sub〉3〈/sub〉) sensors by theoretical calculation and experimental testing. However, its NH〈sub〉3〈/sub〉 sensing properties still need to be enhanced. In this short communication, the gas sensor based on TiO〈sub〉2〈/sub〉/Ti〈sub〉3〈/sub〉C〈sub〉2〈/sub〉T〈em〉〈sub〉x〈/sub〉〈/em〉 bilayer film is fabricated for enhancing the NH〈sub〉3〈/sub〉 sensing properties of pure Ti〈sub〉3〈/sub〉C〈sub〉2〈/sub〉T〈em〉〈sub〉x〈/sub〉〈/em〉. The results show that the TiO〈sub〉2〈/sub〉/Ti〈sub〉3〈/sub〉C〈sub〉2〈/sub〉T〈em〉〈sub〉x〈/sub〉〈/em〉 sensor exhibits larger response value (1.63 times) and shorter response/recovery times (0.65/0.52 times) that of pure Ti〈sub〉3〈/sub〉C〈sub〉2〈/sub〉T〈em〉〈sub〉x〈/sub〉〈/em〉 sensor to 10 ppm NH〈sub〉3〈/sub〉 at room temperature of 25 °C (60.8% relative humidity). Meanwhile, the TiO〈sub〉2〈/sub〉/Ti〈sub〉3〈/sub〉C〈sub〉2〈/sub〉T〈em〉〈sub〉x〈/sub〉〈/em〉 sensor is of good linear response (R〈sup〉2〈/sup〉 = 0.95596) at 2–10 ppm NH〈sub〉3〈/sub〉 and can respond to NH〈sub〉3〈/sub〉 as low as 0.5 ppm. This work is expected to provide useful reference for the development of high performance Ti〈sub〉3〈/sub〉C〈sub〉2〈/sub〉T〈em〉〈sub〉x〈/sub〉〈/em〉-based NH〈sub〉3〈/sub〉 sensors.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Taoping Liu, Wentian Zhang, Lin Ye, Maiken Ueland, Shari L. Forbes, Steven W. Su〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The electronic nose (e-nose) is an olfaction system that consists of an array of chemical sensors and effective machine learning algorithms for the detection of various target odours. Feature extraction and classification methods are of great importance in improving the performance of the e-nose system. In this paper, a novel odour identification method is presented. Firstly, we use the kernel-based system modelling approach to extract odour features. Its solution is a series of finite impulse responses which containing discriminant information of different odours. In addition, a parameter optimisation method based on normalised mean square error and information entropy is proposed to optimise the kernel function. The entropy is effective in preventing the finite impulse responses from overfitting. Multi-odour classification is achieved based on Gaussian mixture density hidden Markov model (GMM-HMM) considering the characteristic of the extracted features. Also, parameter selection for GMM-HMM is realised according to BIC index and cross-validation. Then, we validate the performance of the proposed feature extraction method in resistance to noise and compare it with other existed features. The modelling-based feature reached the highest performance even without applying any filtering or smoothing techniques. Finally, we compare the proposed combination of feature extraction and classification algorithms with other approaches. The proposed method outperformed other approaches reaching 93.56% in sensitivity and 98.71% in specificity. The results demonstrate that the proposed method is applicable in e-nose-based odour identification.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Gisela Ruiz-Vega, Teresa Garcia-Berrocoso, Joan Montaner, Eva Baldrich〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Using magnetic beads (MB) allows producing relatively fast and simple electrochemical magneto-immunosensors. However, this type of sensor implies carrying out serial MB incubation and washing steps in tubes using external magnets, a procedure that requires user training and is tedious and time consuming. In this work, a paper device has been developed that allows performing MB washing and electrochemical detection on-chip with less intervention of the user.〈/p〉 〈p〉In order to achieve this goal, we optimized a single-step magneto-immunoassay for matrix metalloproteinase 9 (MMP-9) detection. Electrochemical detection was then carried out using a customized multiplexed holder that incorporated 8 screen-printed carbon electrodes (SPCE) and a movable multiplexed fluidic module. This paper device provided along the assay sequential MB confinement under static conditions, reagent adsorption and MB washing under flow conditions, and electrochemical detection under static conditions. As we show, the sensor produced in this way achieved detection of MMP-9 in about 10 min, with lineal response spanning 0.03–2 ng mL〈sup〉−1〈/sup〉, detection limit of 0.01 ng mL〈sup〉−1〈/sup〉 and quantification limit of 0.09 ng mL〈sup〉−1〈/sup〉. Furthermore, MMP-9 quantification in 18 plasma samples from patients correlated linearly with the estimates of a reference ELISA that took 〉5 h. These results demonstrate that paper microfluidics can be exploited to simplify magneto-immunosensor manipulation, providing fast, simple and sensitive assay formats.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310962-ga1.jpg" width="337" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Hao Yuan, Yi Pan, Jingxuan Tian, Youchuang Chao, Jingmei Li, Ho Cheung Shum〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Using droplet microfluidic picoinjection as a reactant dosing technique is of great importance in assembling artificial cells and performing multistep reactions. However, the utilization of electricity in the existing picoinjection complicates the device fabrication and operation, and compromises the bioactivity of the encapsulated bio-ingredients. In this work, we propose an electricity-free picoinjection technique as an alternative to address these issues. Specifically, by precisely controlling the pressures inside the microfluidic channel, we can inject one reactant into the flowing droplets that contain another reactant without applying the electric field. Furthermore, the dosed volumes can be tuned by controlling the value of external pressure or the ratio of flow rates between the continuous and droplet phases. To demonstrate the robustness of the proposed picoinjection, we apply it to synthesize crystals and nanoparticles. In the synthesis of crystals, the proposed picoinjection eliminates the problem of device fouling that occurs in the current reactant dosing devices. In the synthesis of nanoparticles, the proposed picoinjection generates nanoparticles that are highly monodispersed. As a result, this simplified picoinjection potentially extends the application of droplet microfluidics to investigate reaction dynamics or biochemical processes in cells. Besides, by eliminating the electricity, the proposed picoinjection avoids the usages of large equipment such as large power supplies or complicate devices, enhancing the accessibility of the proposed picoinjection.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): D. Grondin, P. Breuil, J.P. Viricelle, P. Vernoux〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Resistive soot sensors capable of measuring the mass concentration of particles in an exhaust pipe have been developed in a previous work. In particular, it has been shown that these sensors have an optimal sensitivity for a certain polarization voltage depending on the nature of the particles.〈/p〉 〈p〉This work shows that this effect can be explained by an equilibrium between the creation of soot bridges between the two collecting electrodes and their destruction initiated by Joule effect due to the polarization voltage. Based on this assumption, a model is proposed to predict the load curve (response versus time) of the sensor.〈/p〉 〈p〉In addition, the high frequency sampling of the sensor response has revealed some jumps of the sensor response (electrical conductance), which are exploited through a statistical approach to obtain additional information on the nature of the collected particles.〈/p〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Xuechao Xu, Linjie Wang, Xiaobo Zou, Shuwen Wu, Jianming Pan, Xin Li, Xiangheng Niu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Given that hypertoxic arsenite (As〈sup〉3+〈/sup〉) poses a serious threat to the environment and global health, developing high-performance, low-cost and easy-to-use approaches to specifically monitor As〈sup〉3+〈/sup〉 in environmental matrices turns to be of great importance. In the present work, we reported a novel colorimetric assay of As〈sup〉3+〈/sup〉 based on the reassembly-induced oxidase-like activity inhibition of dithiothreitol-capped Pd nanoparticles (Pd-DTT). The Pd-DTT nanozyme exhibits good oxidase-like catalytic activity to trigger the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of O〈sub〉2〈/sub〉, forming a blue product TMBox. When As〈sup〉3+〈/sup〉 exists, it can chelate the sulfydryl groups in DTT more strongly, leading to a reassembly of Pd-DTT. Compared with the original nanozyme, the reassembled one has much less oxidase-like activity, resulting in the significantly suppressed TMB reaction. Based on this principle, highly sensitive detection of As〈sup〉3+〈/sup〉 was achieved, providing a wide linear range from 33 ng L〈sup〉−1〈/sup〉 to 333.3 μg L〈sup〉−1〈/sup〉 and an ultralow detection limit of 35 ng L〈sup〉−1〈/sup〉. With the help of EDTA as a chelating agent, the method could also offer excellent selectivity for the determination of As〈sup〉3+〈/sup〉 against other metal ions. Besides, our colorimetric assay was employed to accurately measure the analyte in spiked drinking and river water, revealing its great promise in environmental analysis application.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Li Wang, Huihui Liang, Mengli Xu, Linyu Wang, Yi Xie, Yonghai Song〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, a covalent organic framework with dual-pore sizes prepared by ammonia-aldehyde condensation reaction (COFETTA-TPAL) was proposed to load microperoxidase-11 (MP-11) and glucose oxidase (GOD) for ratiometric electrochemical glucose biosensing. The COFETTA-TPAL were flexible two-dimensional (2D) nanosheets with highly ordered crystalline conjugated structure and dual-pores of 3.06 nm and 0.87 nm. The size of MP-11 and GOD matched with its large and small pore well and accordingly they could be embedded into the pores of COFETTA-TPAL through pore encapsulation and hydrogen bond between N-doped skeleton of COFETTA-TPAL and −COOH of MP-11 and GOD. The good flexibility allowed them to be firmly attached to the electrode surface, just like chitosan and nafion which were usually used to modify electrode. The GOD-MP-11−COFETTA-TPAL modified electrode exhibited the reduction peak of COFETTA-TPAL near 0.15 V (〈em〉j〈/em〉0.15 V) and the reduction peak of MP−11 at −0.4 V (〈em〉j〈/em〉−0.4 V). The 〈em〉j〈/em〉−0.4 V was decreased gradually and the 〈em〉j〈/em〉 0.15 V was kept constant with the adding of glucose. The 〈em〉j〈/em〉−0.4 V/〈em〉j〈/em〉0.15 V linearly reduced with the glucose concentration varied from 0.017 mM to 3 mM, and the detection limit was 4.97 μM. The biosensor also displayed good selectivity, stability and reproducibilty. The work successfully proved the application of COF as support platform to load enzymes/proteins for electrochemical biosensors.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310585-ga1.jpg" width="266" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Peng Yu, Yuanming Zhai, Rui-Ying Bao, Zheng-Ying Liu, Ming-Bo Yang, Wei Yang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In chemical industry, elemental sulfur (S) is widely used and always causes environmental and pollution concerns. Hence, the rapid and simple detection of S has become an important issue. In this work, we report an effective approach for visible determination of S. The color of the detection reagent, which was readily prepared by mixing N, N-Dimethylformamide and hydrazine hydrate in a certain ratio, changes from colorless to blue and gradually fades after getting in contact with trace S. The detection reagent can be used for repeated S detection because of the color fading behavior. By measuring the characteristic absorption intensity during detection or the fading time of the mixture, the content of S in the sample can be readily determined and the detection limit can be as low as 0.32 mg/L. An unstable chromogenic organic clathrate generated during detection was found to be responsible for the chromogenic reaction, as revealed by UV–vis, FTIR, NMR, high resolution mass spectrometry measurements and simulation. Thus, this work presents a simple, fast and device-independent approach that can realize semi-quantitative detection of trace S in water, alcohol, food and environmental samples.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311475-ga1.jpg" width="263" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Oksana V. Monogarova, Aleksandr A. Chaplenko, Kirill V. Oskolok〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The original approach was developed and used for screening analysis of more than 40 pharmaceuticals (nonsteroidal analgesics and anti-inflammatory drugs, β-adrenoblockers, secretolytics, fluoroquinolones, metabolic stimulants and others) by digital colorimetry with the use of office flatbed scanner. The proposed technique is based on the simultaneous several colorimetric reactions with different molecular sensors placed in a 96-well plate, and its subsequent optical scanning. Computer processing of the bitmap image and multisensory signal discretization allows to obtain a unique barcode suitable for identification and determination of active substances in drugs. This approach can be used for testing the quality of pharmaceuticals.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311086-ga1.jpg" width="369" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Mickaël Mateos, Rita Meunier-Prest, Jean-Moïse Suisse, Marcel Bouvet〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The energy barrier of an organic heterojunction built on ITO electrodes and made from a low conductive sublayer (Cu(F〈sub〉16〈/sub〉Pc)) covered by a highly conductive semiconductor (LuPc〈sub〉2〈/sub〉) is modulated by electrografting of organic layers before depositing the sublayer. Impedance spectroscopy clearly demonstrates the increase of the energy barrier at the ITO – sublayer interface. Additionally, the electrografting is a versatile and promising method for the tuning of heterojunctions. The I(V) characteristics of the heterojunctions are highly modified by the electrografting. The same electromodifications of electrodes carried out on LuPc〈sub〉2〈/sub〉 resistors lead to a modification of their transport properties too. The effect of the grafting of four different aromatic moieties bearing electron-donating and electron-withdrawing substituents is studied. One important feature is that the sensing properties are highly improved compared to the unmodified devices. Thus, the electrografting of dimethoxybenzene doubles the relative response of the heterojunction towards 90 ppm NH〈sub〉3〈/sub〉, as well as the sensitivity in the range 1–9 ppm. This electrografting allows attaining a limit of detection as good as 140 ppb. The modified heterojunctions favorably compete other conductometric transducers for the detection of ammonia, at room temperature and in a broad range of relative humidity.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311670-ga1.jpg" width="227" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Jae-Hun Kim, Ali Mirzaei, Jae Hoon Bang, Hyoun Woo Kim, Sang Sub Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Future gas sensors require minimal power consumption to enable their integration into portable electronics such as smart mobile phones. We developed H〈sub〉2〈/sub〉S gas sensors based on a self-heating effect using metal oxide nanowires (NWs). We fabricated bare SnO〈sub〉2〈/sub〉 NWs, CuO functionalized SnO〈sub〉2〈/sub〉 NWs, and a CuO functionalized SnO〈sub〉2〈/sub〉-ZnO core-shell (C-S) NW sensor, and tested their sensor response towards H〈sub〉2〈/sub〉S gas by applying different external voltages at room temperature. It was found that the CuO functionalized SnO〈sub〉2〈/sub〉-ZnO C-S NW gas sensor had higher response to H〈sub〉2〈/sub〉S gas relative to other tested sensors due to higher self-heating effect, formation of heterojunctions, phase transformation, and spillover effects of CuO nanoparticles. Without external heat, the selective H〈sub〉2〈/sub〉S detection obtained in this work demonstrates the possibility of embedding low power consumption gas sensors in portable devices for detection of H〈sub〉2〈/sub〉S as a biomarker for early diagnosis of diseases.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311803-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Xinyu Yang, Weijia Li, Yueying Zhang, Tong Liu, Xidong Hao, Ri Zhou, Xishuang Liang, Fengmin Liu, Fangmeng Liu, Yuan Gao, Xu Yan, Geyu Lu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A Nafion-based amperometric sensor utilizing Pt-Sn/C sensing electrode was developed to realize the effective detection of H〈sub〉2〈/sub〉S at room temperature. We compared the morphology and gas-sensing properties of two kinds of Pt/C materials prepared by the sodium borohydride reduction method and the ethylene glycol method and found that the latter was significantly better. Pt-Sn/C prepared by the latter method has a uniform morphology and high catalytic activity and achieves efficient detection of H〈sub〉2〈/sub〉S. The sensor could detect 0.2–100 ppm H〈sub〉2〈/sub〉S linearly with a sensitivity of 0.276 μA/ppm. More importantly, the response-recovery time to 50 ppm H〈sub〉2〈/sub〉S was 10 s and 8 s, which signified a very fast rate. Furthermore, the device also exhibited superior selectivity and long-term stability. Such a device has a good application prospect because of its many advantages.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Guojun Weng, Xinju Zhao, Jing Zhao, Jianjun Li, Jian Zhu, Junwu Zhao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The plasmonic spectral sensing method based on the etching of gold nanorods has been a powerful tool in the field of biomedical detection. Among the plasmonic etching sensors, the most popular sensing strategy is the “positive oxidative etching” plasmonic sensor that is based on plasmon blue-shifting due to nanorod shortening. In this study, we proposed a nanoplasmonic detection of dihydronicotinamide adenine dinucleotide (NADH) based on negative oxidative etching: NADH-mediated inhibition of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 induced gold nanorods etching. In the presence of NADH, the bromine intermediates (Br〈sub〉3〈/sub〉〈sup〉−〈/sup〉 and Br〈sub〉2〈/sub〉) used for etching gold nanorods were reduced and consumed, inhibiting the etching rate and resulting in a small blue-shift of the longitudinal plasmon band (LPB). This shift can be utilized to sense the presence of NADH. Under the optimal reaction conditions, the LPB difference (Δλ) of etched gold nanorods and the concentration of NADH had a good linear relationship in the range of 0–4.9 × 10〈sup〉−6〈/sup〉 mol/L. The nanoplasmonic sensing showed a satisfactory preference for NADH over other common substances tested. It was successfully applied to the detection of NADH in PBS solution. This system provides a platform for the detection of targets in NADH-generated enzyme catalysis.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Michael Munther, Dong-Il Moon, Beomseok Kim, Jin-Woo Han, Keivan Davami, M. Meyyappan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The use of printed electronics in conjunction with nanomaterials such as carbon nanotubes (CNTs) proves to be an effective means for simple, efficient and cost-effective chemical and bio sensing applications due to their high surface area to volume ratio and other attractive properties. However, successful commercial implementation of nanosensors has been elusive due to inconsistent performance across the sensors, which translates to decreased credibility and reproducibility. Furthermore, the process uniformity in printed electronics is inferior to solid-state microfabrication technology as printed sensors suffer from material and process-induced variability at the current level of maturity. In order to take advantage of the promise of nanotechnology driven sensors, we herein propose an array of chemiresistors formed on one substrate as a single input multiple output (SIMO) sensor. Then, individual responses from sub-sensors in a SIMO sensor are aggregated and result in a statistical mean response to overcome variability issues. Random sampling was performed in this work from a sufficiently large population of CNT-based sub-sensors to define a representative set whose behavior closely mimics a larger array. The convergence of the population mean is proven from randomly chosen samples beyond a certain number of sub-sensors. An optimal strategy including sensor layout and power consumption is provided based on the resulting data analysis.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Siqi Li, Ao Liu, Zijie Yang, Junming He, Jing Wang, Fangmeng Liu, Huiying Lu, Xu Yan, Peng Sun, Xishuang Liang, Yuan Gao, Geyu Lu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The SnO〈sub〉2〈/sub〉@ Polyaniline (PANI) nanocomposites were successfully synthesized via a combined approach of hydrothermal and 〈em〉in-situ〈/em〉 polymerization. The morphology and structure of the materials were characterized using SEM and TEM. The specific surface area was analyzed by the Brunauer-Emmett-Teller (BET) equation. The results showed that the materials had micro-structure and large specific surface area. The prepared materials were loaded on flexible polyethylene terephthalate (PET) substrate and their gas sensing properties were investigated at room temperature. Comparing with PANI sensor, the 20 mol% SnO〈sub〉2〈/sub〉@ Polyaniline (PASn20) sensor exhibited 6.2 times higher response (R〈sub〉gas〈/sub〉/R〈sub〉air〈/sub〉 = 29.8) to 100 ppm NH〈sub〉3〈/sub〉 at room temperature. Furthermore, the PASn20 sensor possessed the ability to detect low NH〈sub〉3〈/sub〉 concentrations of 10–200 ppb and outstanding selectivity. The enhanced sensing performance was attributed to the micro-structure with large specific surface area and the formation of p-n heterojunctions at the surface between PANI and SnO〈sub〉2〈/sub〉.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Tong Bu, Meng Zhang, Xinyu Sun, Yongming Tian, Feier Bai, Pei Jia, Yaowen Bai, Taotao Zhe, Li Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A simple and novel immunochromatographic assay (ICA) was developed for specific and sensitive determination of ochratoxin A (OTA) employing microorganism (MO) as reducers and carriers. In this work, microorganism loaded gold nanoparticles (MO@AuNPs) composites were synthesized by reacting Yeast/Lactobacillus (LAB) with HAuCl〈sub〉4〈/sub〉 via biosorption and subsequent bioreduction. The synthesis conditions (pH and reaction time) and main parameters (morphology, diameter and functional groups) of MO@AuNPs were investigated. Owing to the large sizes (about 2 μm) and high adsorption abilities of MO@AuNPs, the few antibodies were labeled, resulting a lower detection limit for ICA. After optimization, the linear detection of OTA using MO@AuNPs-based immunoassay ranged from 0.1 to 1.6 ng/mL, and the visual limit of detection (vLOD) was 0.1 ng/mL, which was nearly 8-fold lower than traditional AuNPs-ICA. Meanwhile, the proposed strategy also possessed high specificity for OTA against other mycotoxins. The applicability of the platform was successfully assessed through the detection of OTA in rice, corn, ginger and green bean samples. The results indicated that these creative sensing elements are promising alternatives and bring an innovative inspiration for biological detections.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311682-ga1.jpg" width="280" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Paramasivam Balasubramanian, Muthaiah Annalakshmi, Shen-Ming Chen, Tse-Wei Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Exploration of rapid, low-cost and more efficient glucose sensing systems has becoming a hot research topic to inspire researchers to discover new electrocatalyst with excellent electrocatalytic sensing performance. Herein, we used a simple hydrothermal method for the preparation of ilmenite-type of NiMnO〈sub〉3〈/sub〉 (NMO) nanostructure. Results of surface morphological analysis reveals that the NMO appeared as interconnected ultrathin nanosheets-like (particle size=∼15 nm) structure, which helps to promote the diffusion of ions into the electrode surface, thus can get improved electrocatalysis. Further the successful formation of NMO was confirmed by X-ray diffraction and X-ray photoelectron microscopic measurements. After these surface analysis, as-synthesized NMO nanosheets were utilized as an electrocatalyst for enzymeless glucose sensing. As-fabricated sensor realized a broad dynamic range (0.00005–1.01 mM and 1.01–13.2 mM) and a lower detection limit as 14 nM with an excellent sensitivity of 7560.8 μA mM〈sup〉−1〈/sup〉 cm〈sup〉-2〈/sup〉. We also demonstrated the practicality of the developed sensor in determination of glucose in human blood serum, and some noninvasive samples such as saliva, and sweat samples and recoveries were reliable with the commercial glucose sensor. These results demonstrate that the present work could lead to a new generation of enzyme-less glucose sensor for clinical analysis and biochemical industries.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311736-ga1.jpg" width="343" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Xiaodan Zhang, Ai Yuan, Xuanxiang Mao, Qiumeng Chen, Yuming Huang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report that the Co/Mn oxides nanocomposite, obtained by directly pyrolying cobalt doped Mn-BTC precursor, is a new oxidase mimetic for colorimetric sensing of acid phosphatase (ACP). By tuning the molar ratios of cobalt ions to Mn-BTC (BTC = 1,3,5-benzenetricarboxylate) precursor, four bimetal Co/Mn-BTCs and their derivatives were obtained. These Co/Mn oxides showed 1.4-fold to 2.6-fold higher oxidase-like activity than that of Mn〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 derived from Mn-BTC, indicating that Co-doping is an effective way for improving and tuning oxidase-like activity of manganese oxides. The rambutan-like Co/Mn oxides with Co/Mn molar ratio of 0.33 (denoted CMO-0.33) in the MOFs precursors exhibited the highest oxidase-like activity. The estimated Michaelis constant for 3,3′,5,5′-tetramethylbenzidine (TMB) was 2.26-fold lower than that of Mn〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, indicating its stronger affinity to TMB. Based on the inhibitory effect of ascorbic acid (AA) on the TMB-CMO-0.33 system, a new colorimetric strategy was paved for screening ACP activity when coupled with L-ascorbic acid 2-phosphate trisodium salt (AAP) because ACP could catalyze hydrolysis of AAP to generate AA. The proposed colorimetric biosensor allows detection of ACP in the range 0.02–1.0 U/L with a limit of detection of 8.2 mU/L. Its potential utilization in ACP assay in human serum samples is successfully demonstrated.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A new oxidase mimetic was developed based on the derivatives of cobalt-doped Mn MOFs for the sensitive acid phosphatase assay.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092540051931127X-ga1.jpg" width="373" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Shuzhi Liu, Di Yang, Yijiang Liu, Hua Pan, Hongbiao Chen, Xiaozhong Qu, Huaming Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, a novel water-soluble fluorescent probe (BODIPY-P) was designed and synthesized for HClO detection. The probe exhibited ratiometric fluorescence variation with rapid response upon addition of NaClO in deionized water (PBS buffer, pH 7.4) and the change of fluorescence color from red to orange was distinguishable by the naked eyes. The ratio of fluorescence intensity (F〈sub〉567〈/sub〉/F〈sub〉629〈/sub〉) gradually increased and showed a good linear correlation with HClO concentration in the range of 0–5 eq. The detection limit was estimated to be 31.6 nM, which enables the quantitative detection of trace amount of HClO realizable. Fluorescence titration experiments demonstrated that the probe was highly selective and competitive over other ROS, biothiols, common anions, physiological relevant cations. The recognition mechanism of the probe towards HClO was proved to be HClO-promoted oxidative cleavage of olefinic C〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/dbnd"〉C double bond. Most importantly, the fluorescence imaging of BODIPY-P in L929 cells suggested that the probe was cell membrane permeable and low toxic, which was capable of monitoring exogenous and endogenous HClO within a few seconds.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311360-ga1.jpg" width="457" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 299〈/p〉 〈p〉Author(s): Xingxing Jiang, Shuping Liu, Minghui Yang, Avraham Rasooly〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bacterial plate count for general assessment of water quality requires lengthy bacterial culturing. We report here a new DNA induced current genosensor for culture independent total bacteria determination. Since the amount of bacterial DNA is correlated to the number of bacteria, the genosensor measures the amount of bacterial DNA to determine bacterial count. The approach relies on bacteria lysis to release DNA which can react with molybdate to form redox molybdophosphate and measured electrochemically. Analysis of 〈em〉E. coli〈/em〉 and 〈em〉S. aureus〈/em〉 demonstrated that the DNA generated current is highly correlated with the level of bacteria lysis which was confirmed by spectrometric measurement. Culture independent measurement of 〈em〉S. aureus〈/em〉 bacterial load suggests limit of detection is 21.9 CFU/mL, with linear range from 3 × 10〈sup〉2〈/sup〉 to 3 × 10〈sup〉7〈/sup〉 CFU/mL and correlation coefficient of 0.992. For 〈em〉E. coli〈/em〉 analysis, the detection limit is 25.1 CFU/mL with the same linear range. The use of electrochemical microbial DNA quantitation for culture independent bacterial count is a new approach, the genosensor measurement is rapid (within 1 h) and has potential use for analysis of broad-spectrum bacteria for various applications.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉By combining microbial cell lysis and DNA induced current detection, we develop a new genosensor for culture independent total bacteria determination.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311438-ga1.jpg" width="333" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Amirmohammad Seif, Alireza Nikfarjam, Hassan Haj ghassem〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉TiO〈sub〉2〈/sub〉/PANI core-shell nanofiber thin film sensors are fabricated by in-situ chemical polymerization on electrospun TiO〈sub〉2〈/sub〉 nanofibers, and evaluated for NH〈sub〉3〈/sub〉 gas sensing application with UV irradiation at room temperature (25 °C). Fully rutile and 30% anatase-70% rutile mixed phase TiO〈sub〉2〈/sub〉 nanofibers are used as n-type core material. PANI as a p-type shell has porous morphology and FE-SEM results reveal that the average thickness of PANI shell is about 20 nm, which is in the order of Debye length resulting a higher sensitivity. Experimental result reveals that the sensor with combined phase core has a higher photo-assisted response. Moreover, the effect of various UV light intensities on TiO〈sub〉2〈/sub〉/PANI core-shell nanofiber show maximum response at intermediate UV light intensity. Besides, UV light exposure led to a considerable reduction in recovery and response times to approximately one-fifth of their value. Ammonia sensing property is also evaluated at different humidity levels upon exposure to UV light and shows that higher humidity content leads to increase in sensor response. High sensitivity and low detection limit as low as 50 ppb under high humidity condition and excellent selectivity for various VOCs make the proposed sensor to be a good candidate for breath analysis applications.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311050-ga1.jpg" width="382" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Nan Zhang, Shengping Ruan, Fengdong Qu, Yanyang Yin, Xin Li, Shanpeng Wen, Samira Adimi, Jingzhi Yin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Constructing complex interior nanostructures by metal-organic framework (MOF)-assisted strategy have attracted tremendous attention in the field of material science. Herein, the Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉/CoFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 double-shell nanocubes (CCFO DSNCs) were synthesized by a metal–organic framework (MOF) route. The approach included the formation of a zeolite imidazolate framework-67 (ZIF-67)/Co–Fe Prussian blue analogue (PBA) core–shell nanocubes (CSNCs) precursor and then transformation to CCFO DSNCs by thermal annealing in air. A series of techniques were employed in order to investigate the morphology and structure of the CCFO DSNCs. The gas sensing properties of CCFO DSNCs were studied systematically. The results showed that the CCFO1 DSNCs sensor showed a high response toward formaldehyde with fast response and recovery speeds, and low detection limit (300 ppb). The enhanced properties were attributed to the double-shell nanostructure and the heterojunction between Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 and CoFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092540051931086X-ga1.jpg" width="353" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Zhen Yang, Ning Wang, Hao Wen, Ruiming Cui, Jia Yu, Shuo Yang, Tongtong Qu, Xueting Wang, Songlin He, Jun Qi, Jin Wang, Qing Ye, Yin Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sensitive and specific identification of pathogen is in great demand but remains challenging. Herein, we developed an endonuclease dependence molecular beacon assay (DEMBA). We firstly labeled the DEMBA probes by a 6-Carboxyfluorescein at the 5’-end as the fluorophore and a black hole quencher at the 3’-end. Then we recorded the fluorescence signals for analyzation. In addition, the lateral flow dipstick (LFD) DEMBA probes are labeled with fluorescein isothiocyanate (FITC) at the 5’‑end, and biotin at the 3’-end. The digested LFD DEMBA probes can be detected by visual inspection of a colorimetric signal on a lateral flow dipstick. In fluorescence method, we detected ssDNA molecules down to 1 pM and ssRNA to 10 pM within 10 min. Meanwhile, in lateral flow dipstick method, the ssDNA and ssRNA molecules detection limits are 10 pM. Successfully, we also detected the single nucleotide spot mutation (SNP) without false positive or false negative interpretation. Furthermore, the DEMBA is an amplification-free method, which can avoid the aerosol pollution and be easy-to-perform. In conclusion, the DEMBA is an isothermal detection method with simple design, high sensitivity, wide-ranged application, easy operation and time saving.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311001-ga1.jpg" width="266" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Yu Cheng, Kai Ren, Chao Huang, Jie Wei〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Light-driven hydrogel actuators show increasing advantages in flowing control, soft robot and microreactor. Herein, we proposed one photothermal responsive and self-healing nanocomposite hydrogel containing poly(N-isopropylacrylamide) (PNIPAM) and poly(N,N-dimethylacrylamide) (PDMAA) to serve as light-driven valves by stimulating the bilayer and “hinge-type” hydrogel composites. With graphene oxide (GO) and clay, the hydrogels possess good mechanical property and near-infrared (NIR)-driven self-healing behavior because of the non-covalent bonding between the polymer chains and clay. Such bilayer-type hydrogels present local folding with the guide of NIR laser and can realize solid/liquid transportation and controllable trigger of the reaction. We proposed the integration of inhomogeneous structure via NIR light healing to form “hinge-type” hydrogel, consisting of one bilayer hydrogel as the “hinge” section and two PDMAA hydrogels as the “blade” section. The “hinge-type” hydrogel presents repeatable and obvious deformation with irradiation. Thus, the photothermal responsive and self-healing hydrogel may have potential applications in soft actuator, microfluidic, and microreactor.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉One photothermal responsive and self-healing nanocomposite hydrogel serves as flowing valve by stimulating the bilayer and “hinge-type” hydrogel composites.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311074-ga1.jpg" width="384" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Sumei Wang, Yichen Guo, Yanjun Xue, Xinzhen Wang, Hongzhi Cui, Jian Tian〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The widespread heterophase structure or p-n junction strategies fabricated between different semiconductors are generally used to promote the charge separation in gas-sensing and photocatalysis, which originated from the principle that the composites possess totally different crystalline and energy structures. A vagarious and supreme challenge remained as to whether a junction could be formed between the identical composites with the same semiconductors and the crystalline phases. Herein, a homophase nanostructure is fabricated between the same crystalline phases of SnO〈sub〉2〈/sub〉 with nanosheets and nanoparticles. Excellent sensitivity (602.1 at 100 ppm), broad detection range, low detection limit (ppb-level), selectivity toward ethanol and stability, can be remarkably achieved using such homophase structure strategy. The high gas sensing activities are proposed to be attributed to the different surface band bending inducing the formation of a built-in electric field at the interface of nanosheets and nanoparticles, which facilitates the electrons transfer from SnO〈sub〉2〈/sub〉 nanosheets to SnO〈sub〉2〈/sub〉 nanoparticles, enabling effective electron exchange between the composite and external ethanol gas. Furthermore, the abundant active sites induced by the small and well-dispersed SnO〈sub〉2〈/sub〉 nanoparticles on the surface of SnO〈sub〉2〈/sub〉 nanosheets and the increase of oxygen adsorption also improve the sensing performance. Our work provides a strategy for charge separation in constructing highly efficient gas sensing systems, which is differentiated from the traditional junction strategies.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519311396-ga1.jpg" width="220" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Chao Yuan, Alexander Bowler, Jonathan Gareth Davies, Buddhika Hewakandamby, Georgios Dimitrakis〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Measurements of the composition of multiphase flows, especially water-cut in oil-water flow, is a frequently encountered problem in the petroleum industry. New techniques that can offer improvements towards that are continuously sought and the use of microwave sensors is considered very promising. The current paper reports on the performance of a microwave cylindrical resonator, integrated into a multiphase flow experimental facility, used to determine water-cut in an upward flowing oil-water mixture. The performance and suitability of two microwave resonant modes (TM〈sub〉010〈/sub〉 and TM〈sub〉110〈/sub〉) was studied. The TM〈sub〉110〈/sub〉 mode was found to be less dependent on the spatial phase distribution of the oil-water flowing mixture and provided more consistent results across a broader flow regime. The relative errors between the predicted and actual water-cut were from −6.53% to 9.16% and relative errors of 78% of the total data points were inside −5% to 5%. The results suggest that appropriate sensor design and careful selection of the operating frequency/resonant pattern can offer a powerful technique for real time, on-line and non-destructive determination of water-cut in multiphase flow systems.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Tong Sun, FengChun Tian, YuTian Bi, XiaoZheng Zhong, Jiao He, TaiCong Yang, QingShan Guo, Ying Lei, YanYi Lu, Lin Zeng, QingHua He〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Infections have long been a thorny problem that severely threatened public health and resulted in tremendous economic losses worldwide. Current detection methods for wound infection do not fully meet the requirements of preventing and treating this disease. Therefore, people are looking for better alternatives, wherein FAIMS (Field Asymmetric Ion Mobility Spectrometry) technology, by virtue of its high sensitivity, rapid response and noninvasive operation, is a promising candidate. This paper aims to investigate the possibility of FAIMS technology in detecting wound infections quickly and accurately. For this purpose, we gathered an odor dataset of clinical wound samples with the employment of a FAIMS instrument, the Lonestar (Owlstone, UK) analyzer. To enhance detectability, we proposed a novel algorithm framework, i.e., Local Warning integrated with Global Feature (LWGF), which is verified on distinguishment between twenty patients with single or mixed infection of 〈em〉Escherichia coli〈/em〉 (〈em〉E. coli〈/em〉) and six wounded patients without infection. Experimental results showed that the LWGF successfully identified the patients with the best average AUC of 0.98, and the best recognition rate of 96.15%, which are much higher than the conventional methods.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Vitaly Panchuk, Valentin Semenov, Julia Ashina, Andrey Legin, Konstantin Mikhelson, Dmitry Kirsanov〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉There is a serious lack of instrumental studies of polymeric membrane ion sensors that would give reliable information on the chemistry behind the sensor response. These types of studies are quite challenging due to the low content of species of interest in the membrane material and due to specific features of plasticized polymeric sensor membranes. Mössbauer spectroscopy is a powerful tool for studying local chemical environment of the probe atom. In this research we explored the forms of iron existence in different PVC-plasticized membranes containing Fe-binding ligand and cation-exchanger. In order to be able to observe Mössbauer effect we employed 〈sup〉57〈/sup〉Fe-enriched sample solutions to soak the membranes and performed the measurements at 80 K to increase the recoil-free factor. It was found that the chemical forms of iron are different in membranes containing the ion-exchanger and those containing both ion-exchanger and the ligand. The relative content of iron in various forms was estimated. It was also observed that iron ions enter into the «dummy» membranes with no ligand and ion-exchanger, however in very small amounts.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Rebeca Jiménez-Pérez, José González-Rodríguez, María-Isabel González-Sánchez, Beatriz Gómez-Monedero, Edelmira Valero〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The sensitive determination of hydrogen peroxide has broad analytical applications. In this work, a novel non-enzymatic hydrogen peroxide sensor based on Pt nanoparticles (PtNPs) electrochemically deposited on previously modified and activated screen-printed carbon electrodes (aSPCEs) was constructed. The pretreatment consisted of subjecting the electrodes to a surface activation treatment with hydrogen peroxide followed by the electrodeposition of poly(azure A) films (PAA) in a sodium dodecyl sulfate micellar aqueous solution. The PtNPs/PAA/aSPCEs were characterized by scanning electron microscope, X-Ray photoelectron spectrometry, linear scan voltammetry and electrochemical impedance spectroscopy. Linear sweep voltammograms showed that the oxidation peak potential of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 shifts from ˜1 V at SPCEs to ˜0.1 V at PtNPs/PAA/aSPCEs. The fabricated electrodes showed excellent electrocatalytic activity towards H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 oxidation, making its detection possible at 0.1 V. The detection limit was 51.6 nM, which is significantly lower than other modified electrodes found in the literature, and the linear range ranging from 0 to 300 μM. The proposed electrode was successfully applied to the determination of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 in real samples in different areas. Additional experiments against common interfering agents (ascorbic acid, dehydroascorbic acid, glucose, salicylic acid, among other compounds) showed no increase in the current signal and only in the case of ascorbic acid a small interference, not greater than 10% is observed, which indicates high specificity of the sensor. These electrodes open up alternative avenues for the development of highly sensitive, robust and low cost electrochemical H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 sensors for field tests.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Manuel Izquierdo, Alberto Villa-Martínez, Miguel Lastra-Mejías, Regina Aroca-Santos, John C. Cancilla, José S. Torrecilla〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A computerized approach to quickly, easily, and efficiently detect discharged sewage of the cheese sector into rivers or reservoirs has been presented in this work. It is based on developing and/or training linear regression, linear multiple regression, and multilayer perceptron-based models using the data obtained from measuring different contaminated waters with a portable digital refractometer. This equipment measures the refractive index, Brix degrees, and salinity of aqueous samples. To carry it out, 451 samples were made by mixing five different waters with cheese whey from the Spanish “Fábrica de quesos de Villalón de Campos S.L.”. The water samples used were distilled water and four non-drinkable waters taken from four different Spanish locations (the Valmayor Reservoir, the Mari Pascuala Lagoon, the Manzanares River and the Guadarrama River). The lowest mean absolute percentage error (0.79%) was achieved using three independent variables and a multilayer perceptron-based model. The validation of this approach has been done in two ways: k-fold cross-validation and internal validation. The outcome of this research is a new method for a fast detection of waste spillages into rivers and reservoirs.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310949-ga1.jpg" width="339" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 298〈/p〉 〈p〉Author(s): Dorota Zembrzuska, Jakub Kalecki, Maciej Cieplak, Wojciech Lisowski, Pawel Borowicz, Krzysztof Noworyta, Piyush Sindhu Sharma〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, we report an electrochemically initiated co-polymerization of two electroactive monomers of different oxidation potentials. The molar ratio of low oxidation potential monomer in the solution for electropolymerization was optimized to find condition suitable for co-polymerization of high-oxidation potential monomer effectively at lower oxidation potential. The XPS analysis confirmed successful co-polymerization. This co-polymerization condition was further used in imprinting of melatonin, an electroactive compound. Entrapment of melatonin in the polymer matrix was confirmed by measuring electroactivity of melatonin in the 0.1 M KCl−HCl solution (pH 1.6). This MIP based electrochemical sensor determined melatonin in the linear dynamic concentration range 10–80 μM. Detectability of proposed chemosensor was 0.14 μM (S/N = 3). The mean RSD for the concentration range studied was ∼20%. Selectivity of the chemosensor was satisfactory towards common structural analogues and biomolecules. Furthermore, the chemosensor was successfully used to determine melatonin in real samples. The sensitivity in the presence of matrix components and that for the KCl−HCl solution were quite similar. The results obtained indicate the suitability of the devised chemosensor for practical applications.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400519310834-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉