ALBERT

Beschreibung: 〈p〉Publication date: Available online 27 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Fares Zouaoui, Saliha Bourouina-Bacha, Mustapha Bourouina, Imad Abroa-Nemeir, Hamdi Ben Halima, Juan Gallardo-Gonzalez, Nadia El Alami El Hassani, Albert Alcacer, Joan Bausells, Nicole Jaffrezic-Renault, Nadia Zine, Abdelhamid Errachid〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The toxicological and environmental damage caused by glyphosate [N-(phosphonomethyl) glycine] (GLY) has been well documented, however, limited efforts have been made to detect it in the environment. In response to that, we report the development of an extremely sensitive electrochemical sensor for GLY detection in water. This novel concept of glyphosate sensor is based on molecularly imprinted polymer (MIPs) made of chitosan (CS) biopolymer electrochemically deposited onto a gold microelectrode. Electrochemical Impedance Spectroscopy (EIS) was used for the label free detection of GLY in a linear range from 0.31 pg/ml to 50 ng/ml with a low detection limit of 0.001 pg/ml (S/N = 3). Moreover, the success of the MIPs layer affinity to GLY was confirmed through detection of GLY with non-imprinted CS (NIPs); a good imprinting factor of 14.5 was obtained. The selectivity of the MIPs was verified with the detection of different pesticides as interferences. Very high selectivity factors (SF) were obtained: 7.9 for glyfosinate, 43.5 for chlorpyrifos and 14.5 for phosmet.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520301003-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 27 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Meiling Tian, Wenyue Xie, Ting Zhang, Yang Liu, Zhisong Lu, Chang Ming Li, Yingshuai Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This work reports a low-cost, fast and highly sensitive lateral flow immunoassay (LFIA) platform with Prussian blue nanoparticle (PBNP) as a new reporter, which efficiently mediates an on-demand cascade signal amplification by catalyzing oxidation of chromogenic reagent 3,3’,5,5’-tetramethylbenzidine (TMB). In this case, PBNPs are accumulated on the test line through the specific immune interaction, resulting in a blue-colored line. The colorimetric signal can be further amplified via the peroxidase mimic PBNP-catalyzed TMB oxidation to produce an insoluble blue-violet precipitate. Under an optimal condition, a limit of detection (LOD) at 10 pg mL〈sup〉-1〈/sup〉is achieved for rabbit IgG (RIgG) detection, which is 2-3 orders of magnitude better than the conventional LFIA strip using colloidal gold nanoparticle as a label. A macromolecular RIgG and a small molecular mycotoxin ochratoxin A (OTA) are also successfully analyzed in mimicking samples, demonstrating its good practicability of the proposed platform in a variety of fields.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520300757-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 27 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): M. Carmen Gonzalez-Garcia, Tomas Peña-Ruiz, Pilar Herrero-Foncubierta, Delia Miguel, Maria D. Giron, Rafael Salto, Juan M. Cuerva, Amparo Navarro, Emilio Garcia-Fernandez, Angel Orte〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The cellular microenvironment is a complex medium due to high concentrations of proteins and an intertwined framework of cellular organelles. In particular, cellular micro-polarity controls several biological processes, since it modulates hydrophobic/hydrophilic interactions and, hence, recognition, signalling and binding events.〈/p〉 〈p〉In this work, we have developed an unprecedented methodology to construct accurate environment polarity images using multiparametric fluorescence microscopy, via a multi-linear calibration of orthogonal parameters: the fluorescence lifetime and the spectral shift of a series of solvatochromic dyes. For this approach, we have synthesized and fully characterized N-substituted 2-methoxy-9-acridone dyes as suitable bioimaging polarity probes. However, to fully comprehend the complex links between microenvironment polarity and the dyes’ properties, we have endeavoured a multidisciplinary approach, in which we have studied the photophysics of our fluorophores using spectroscopic tools and state-of-the-art computational chemistry. This profound knowledge permitted to use these dyes as intracellular polarity probes, quantitatively and robustly probing the microenvironment of different cellular compartments.〈/p〉 〈p〉Our new methodology may pave the way to further developments in accurate sensing of cellular microenvironment parameters.〈/p〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Xuejing Wu, Qinghua Meng, Qiang Zhang, Liuyin Fan, Hua Xiao, Chengxi Cao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we proposed the concept of fluorescent speed sensing (FSS) of glycoprotein in chip supramolecular electrophoresis (CSE). To achieve a stable FSS run, we firstly synthesized a novel boronic acid-based diben-zoxanthene receptor (Rp3) by a simple one-pot reaction and the complex probe of F1@Rp3 containing Rp3 and fluorescein (F1), and performed a series of experiments to assess the complex probe's ability for recognition of saccharides and glycoproteins. Secondly, we revealed the mechanism of 'balance electromigration of supramolecular complex probe' in FSS and developed the relevant theory of FSS via a series of theoretical derivation. The FSS theory showed that the moving speed of F1 was a function of glycoprotein content, indicating a novel model of glycoprotein sensing. To demonstrate the validity and utility of developed model and theory, IgG and ovalbumin were selected as model glycoproteins for the relevant experiments. The results verified the validity of FSS concept to glycoprotein assay with good accuracy (less than 6.33% difference from standard HPLC method), stability (less than 6.04% RSD) and linearity (higher than 〈em〉R〈sup〉2〈/sup〉〈/em〉 = 0.99) as well as fair sensitivity (8.48 ng). Finally, the FSS was successfully used for the analysis of HbA〈sub〉1c〈/sub〉 (a key biomarker in diabetes blood). The developed FSS concept and complex probe have great potential for glycoprotein sensing, particularly for the diagnosis of diabetes.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 22 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Li Jiang, Caileng Wang, Jing Wang, Fangmeng Liu, Rui You, Siyuan Lv, Guoyan Zeng, Zijie Yang, Junming He, Ao Liu, Xu Yan, Peng Sun, Jie Zheng, Geyu Lu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Solid state electrolyte type formaldehyde (HCHO) gas sensors based on a novel pyrochlore structure Gd〈sub〉2〈/sub〉Zr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 solid electrolyte coupled with rod-shaped ZnO sensing electrode (SE) were initially designed and fabricated in this paper. The incorporation of alkaline-earth metal Ca can significantly improve sensing performance of the Gd〈sub〉2〈/sub〉Zr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 based sensors to HCHO. The response value (ΔV) of the sensors based on Gd〈sub〉2-x〈/sub〉Ca〈sub〉x〈/sub〉Zr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 (x = 0, 0.02, 0.05 and 0.1) varied approximately linear with the logarithm of HCHO concentration in the range of 1-100 ppm at 600 °C, with sensitivities of -25, -30, -15 and -5 mV/decade, respectively. The optimal sensor based on Gd〈sub〉1.98〈/sub〉Ca〈sub〉0.02〈/sub〉Zr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 (GCZ(0.02)) exhibited the excellent sensing characteristics with maximum response value (-61.3 mV) and extremely short response time (3 s) to 100 ppm HCHO. In addition, the GCZ(0.02) sensor also showed good selectivity and stability within 20-day period of continuous high-temperature aging under high-humidity condition. Conclusively, the sensing behavior and mechanism based on mixed potential were investigated and demonstrated by the mearsurement of the polarization curves.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Lorena Biondi, Marcus Perry, Jack McAlorum, Christos Vlachakis, Andrea Hamilton〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Moisture plays a critical role in reinforced concrete corrosion, underpinning structural degradation which costs the global economy a staggering $350 bn per year (0.5% GDP). Both moisture sensors and repair materials that limit water ingress are required, but monitoring and maintenance are often viewed as separate challenges. This paper outlines a first-time demonstration of moisture sensors based on low calcium fly ash geopolymers — a class of cementitious, electrolytically conductive repair materials. Electrochemical impedance spectroscopy and equivalent circuit models are used to understand and optimize the electrical response of geopolymer sensors to water content and temperature. Moisture and temperature precisions of 0.1 wt% and 0.1 ° C are demonstrated respectively, and sensor drifts over 20 minute periods were found to be within 1–3%. Sensor responses were also shown to be repeatable to within 3% between wetting and thermal cycles. Results from spectrometry and chromatography analyses link this repeatability to the minimal ion leaching from the sensors. The study demonstrates the feasibility of moisture sensing using geopolymers, and furthers our current understanding of the role of moisture in the ionic conductivity of alkali-activated materials. This work is anticipated to be the first stage in developing 2D, distributed sensor-repairs for concrete structures, and other chemical sensors that support concrete structural health monitoring and prognostics.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Mingshun Li, Yanlong Xing, Yuxia Zou, Guang Chen, Jinmao You, Fabiao Yu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The homeostatic disorder of intracellular Zn〈sup〉2+〈/sup〉 pool is closely associated with severe diseases. It has been reported that the high level of free Zn〈sup〉2+〈/sup〉 during ischemia/reperfusion (I/R) process can result in oxidative stress damage on nerve cells. Given that nitrosyl (HNO) can aggravate the nerve injury during cerebral I/R process, we assume that there may exist a mutual regulation between Zn〈sup〉2+〈/sup〉 and HNO under certain physiological conditions. To reveal this potential small-signaling-molecule crosstalk, we synthesized two-photon fluorescent probes 〈strong〉CHP-H〈/strong〉 and 〈strong〉CHP-CH〈sub〉3〈/sub〉〈/strong〉 to monitor intracellular Zn〈sup〉2+〈/sup〉 in cell and mice hippocampus I/R models. The probes consist of two moieties: coumarin derivative as the two-photon fluorescence transducer, 2-hydrazino pyridine as the fluorescence modulator and Zn〈sup〉2+〈/sup〉 chelator. Both probes exhibit excellent analytical properties for Zn〈sup〉2+〈/sup〉 detection in simulated physiological systems. Utilizing 〈strong〉CHP-H〈/strong〉 and an HNO probe 〈strong〉Cyto-JN〈/strong〉, we perform fluorescent imaging of cell I/R models. The results confirm that HNO can stimulate Zn〈sup〉2+〈/sup〉 release from labile Zn〈sup〉2+〈/sup〉 pool, whereas, the increase of intracellular Zn〈sup〉2+〈/sup〉 cannot upregulate the level of HNO. Combining with the deep tissue imaging of mice hippocampus tissues, our probes may provide potential approaches for the medical diagnostic assessment of HNO regulation effect on Zn〈sup〉2+〈/sup〉 release in clinical cerebral I/R-related diseases.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520301192-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈p〉Two-photon fluorescent probes 〈strong〉CHP-H〈/strong〉 and 〈strong〉CHP-CH〈sub〉3〈/sub〉〈/strong〉 were synthesized and applied to explore the mutual regulation between Zn〈sup〉2+〈/sup〉 and nitrosyl (HNO) in cells and 〈em〉in vivo〈/em〉 models. The probes consist of two moieties: coumarin derivative as the two-photon fluorescence transducer, 2-hydrazino pyridine as the fluorescence modulator and Zn〈sup〉2+〈/sup〉 chelator. Both probes exhibit excellent analytical properties for Zn〈sup〉2+〈/sup〉 detection in simulated physiological systems. Utilizing 〈strong〉CHP-H〈/strong〉 and an HNO probe 〈strong〉Cyto-JN〈/strong〉, we perform fluorescent imaging of cell I/R models. The results confirm that HNO can stimulate Zn〈sup〉2+〈/sup〉 release from labile Zn〈sup〉2+〈/sup〉 pool, whereas, the increase of intracellular Zn〈sup〉2+〈/sup〉 cannot upregulate the level of HNO. Combining with the deep tissue imaging of mice hippocampus tissues, our probes may provide potential approaches for the medical diagnostic assessment of HNO regulation effect on Zn〈sup〉2+〈/sup〉 release in clinical cerebral I/R-related diseases.〈/p〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 309〈/p〉 〈p〉Author(s): Xinrong Guo, Jianzhi Huang, Min Wang, Lishi Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, a new dual-emission water soluble graphitic carbon nitride@gold nanoclusters (WS-GCN@AuNCs) nanocomposite is synthesized by a simple method that AuNCs are in-situ grown on the surface of WS-GCN. This composite material emits yellow fluorescence with two emission wavelengths locating at 430 and 520 nm, and of which direct band gap is different from individual WS-GCN. Its fluorescence intensity at 520 nm is quenched rapidly in the presence of ferrous (Fe〈sup〉2+〈/sup〉) and copper ions (Cu〈sup〉2+〈/sup〉), and relevant fluorescent color changes from yellow to blue, ascribing to the photo-induced electron transfer (PET) mechanism. Furthermore, a reduction strategy of cysteine can be used to distinguish Fe〈sup〉2+〈/sup〉 and Cu〈sup〉2+〈/sup〉. According to this, a new dual-emission WS-GCN@AuNCs-based fluorescent sensor is constructed to detect Fe〈sup〉2+〈/sup〉 and Cu〈sup〉2+〈/sup〉 with the detection limit of 1.73 and 3.63 nmol L〈sup〉−1〈/sup〉, respectively. This proposed method not only exhibits highly selective and sensitive for analysis of Fe〈sup〉2+〈/sup〉 and Cu〈sup〉2+〈/sup〉 under existence of interfering cations, but possesses excellent performance for detection of trace amounts of Fe〈sup〉2+〈/sup〉 and Cu〈sup〉2+〈/sup〉 in environmental water.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Dual-emission WS-GCN@AuNCs-based fluorescent material is synthesized and applied for〈/p〉 〈p〉trace analysis of Fe2+ and Cu2+ in water based on the PET mechanism.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520301131-ga1.jpg" width="257" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 22 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Ming-Chung Wu, Chih-Kunag Kao, Tz-Feng Lin, Shun-Hsiang Chan, Shih-Hsuan Chen, Chi-Hung Lin, Yu-Ching Huang, Ziming Zhou, Kai Wang, Chao-Sung Lai〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Volatile organic compounds (VOCs) are potentially dangerous to the environment and human health. The developed sensing template in this study was prepared by a one-step process on a glass substrate using the electrospinning technique. The sensing material made of the uniaxial aligned CdSe-CdS/Ag/PMMA composite scaffold consists of CdSe-CdS core-shell quantum rods, silver nanoparticles (Ag NPs), and poly(methyl methacrylate) (PMMA) nanofibers. Increasing the specific surface area is beneficial for VOCs harvesting; therefore, the uniaxial aligned CdSe-CdS/Ag/PMMA composite scaffold was slightly treated with UV-ozone etching, and thus efficiently enhancing the extinction changes of VOCs. Also, a high VOC detection capability was demonstrated by the polarization response and Ag surface plasmon resonance of the nanocomposite. A series of typical VOCs and alcoholic VOCs were used for the VOCs sensor practical tests. This VOC sensor achieved a spectacular detection limit of 100 ppm for butanol and 500 ppm for chlorobenzene. The uniaxial aligned CdSe-CdS/Ag/PMMA composite scaffold is a newly designed nanocomposite and can reach the market demands comparing to other commercial high sensitive VOC sensors.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520301076-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 309〈/p〉 〈p〉Author(s): Giulia Barzan, Alessio Sacco, Luisa Mandrile, Andrea M. Giovannozzi, James Brown, Chiara Portesi, Morgan R. Alexander, Paul Williams, Kim R. Hardie, Andrea M. Rossi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To overcome the widespread misuse of antibiotics and reduce the growing problem of multidrug resistance, rapid, sensitive and specific novel methods to determine bacterial antibiotic susceptibility are needed. This study presents a combined dielectrophoresis (DEP) - Raman Spectroscopy (RS) method to obtain direct, real-time measurements of the susceptibility of a suspension of planktonic bacteria without labelling or other time-consuming and intrusive sample preparation processes. Using an in-house constructed DEP-Raman device, we demonstrated the susceptibility of 〈em〉Escherichia coli〈/em〉 MG1655 towards the second-generation fluoroquinolone antibiotic ciprofloxacin (CP) after only 1 h of treatment, by monitoring spectral changes in the chemical fingerprint of bacteria related to the mode of action of the drug. Spectral variance was modelled by multivariate techniques and a classification model was calculated to determine bacterial viability in the exponential growth phase at the minimum bactericidal concentration (MBC) over a 3 h time span. Further tests at a sub-minimum inhibitory concentration (MIC) and with a CP-resistant 〈em〉E. coli〈/em〉 were carried out to validate the model. The method was then successfully applied for class prediction in a biocide cross-induced tolerance assay that involved pre-treating 〈em〉E. coli〈/em〉 with triclosan (TCS), an antimicrobial used in many consumer products. High specificity and adequate sensitivity of the proposed method was thereby demonstrated. Simultaneously, standard microbiological assays based on cell viability, turbidity and fluorescence microscopy, were carried out as reference methods to confirm the observed Raman response.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 309〈/p〉 〈p〉Author(s): Yong Zhang, Jianxu Ren, Yiwei Wu, Xiangli Zhong, Tao Luo, Juexian Cao, Mengqi Yin, Mingpeng Huang, Zhiyong Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ultra-low humidity detection is significant in some important industrial fields, such as integrated circuit manufacturing, chip packaging. However, the traditional ionic-type humidity sensor is not competent for the detection of ultra-low humidity, but can only realize the detection of medium humidity to high humidity. Here, moisture-induced discoloration material Nickel(II) iodide (NiI〈sub〉2〈/sub〉) is found to be highly sensitive to moisture, and both its electrical properties and color will change with environmental humidity variation. Especially, NiI〈sub〉2〈/sub〉 exhibits the largest impedance change to date in the ultra-low humidity range compared with state of the art. The impedance variation is up to 2 orders of magnitude in the range of 0.4 %–11 % RH, which means that NiI〈sub〉2〈/sub〉 can realize the detection of ultra-low humidity. The excellent performance of NiI〈sub〉2〈/sub〉 in ultra-low humidity is attributed to the material transition characteristics susceptible to humidity rather than the traditional surface mechanism of water adsorption. Moreover, combining the reversible black-to-transparency moisture-induced discoloration behavior with humidity sensing properties, a flexible wristband based on NiI〈sub〉2〈/sub〉 is developed to realize the dual-mode detection of wide range environmental humidity. These results demonstrate that NiI〈sub〉2〈/sub〉 has great application prospects in professional ultra-low humidity detection and wearable humidity detection equipment.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 309〈/p〉 〈p〉Author(s): Mingyu Cheng, Fan Zhang, Aonan Zhu, Xiaolong Zhang, Yaxin Wang, Xiaoyu Zhao, Lei Chen, Zhong Hua, Yongjun Zhang, Xuefeng Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Detecting biomarkers with high sensitivity is key for the early diagnosis of hepatocellular carcinoma (HCC). Nanostructure units with knobby surface are bridged to obtain significant surface-enhanced Raman scattering (SERS) signals. This changes the plasma coupling mode and the hotspots distribution between neighboring units as confirmed by finite-difference time-domain simulations. These arrays of bridged knobby units are used to quantitatively analyze the concentrations of α-Fetoprotein (AFP) and AFP-L3 by immunoanalysis using a combination of frequency shifts and intensity changes of SERS. By using these arrays of bridged knobby units as SERS immunochips, the detection limits of AFP and AFP-L3 decrease to 3 pg/mL. This immunoanalytic method has potential value for the diagnosis of early liver cancer in patients, offering advantages of convenience, time saving, low detection limit, and high precision.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Jong Pil Lee, Fadilatul Jannah, Kwangmin Bae, Jong-Man Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Biothiols such as cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) participate in numerous cellular functions and physiological processes. Because changes in the levels of these biological important substances are associated with various clinical disorders and diseases, methods for their selective sensitive and quantitative detection are in high demand. In the current study, we developed a new, selective and sensitive colorimetric and fluorometric biothiol chemosensor that is comprised of a mercury-complexed, pyridine-containing polydiacetylene (PDA). Owing to its high affinity toward sulfur, biothiols promote decomposition of the pyridine-mercury complex in the PDA in conjunction with colorimetric and fluorescence changes. Specifically, upon addition of biothiols the new chemosensor undergoes a blue-to-red color transition and generates red fluorescence. Moreover, incorporation of the chemosensor in electrospun PEO nanofibers leads to an enhanced sensitivity for biothiol detection. The strategy developed in this study should be applicable to the design of other thiol-specific sensors that utilize pyridine-containing conjugated molecules.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 309〈/p〉 〈p〉Author(s): Minggang Zhao, Zhengming Li, Xiaomin Zhang, Jiatuo Yu, Yu Ding, Hui Li, Ye Ma〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electrochemical sensing signal is easily interfered by substance with similar redox, which is difficult to be eliminated. The adjusting effect of interfacial barrier on electrochemical response was proposed to suppress this interference. Porous reduced graphene oxide encapsulated ZnO microspheres were prepared and used for detecting dopamine. The response to dopamine is enhanced and the responses to ascorbic acid and uric acid are decreased by changing the barrier height. An ultrahigh sensitivity (1240.74 μA mM〈sup〉−1〈/sup〉 cm〈sup〉-2〈/sup〉) with a wide linear range is 1−600 μM and excellent selectivity to dopamine is achieved. Employing the interfacial barrier to adjust electrochemical response is a promising approach to improve the specificity and sensitivity of electrochemical sensors.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Xia Cheng, Yuying Chai, Jian Xu, Lin Wang, Fangdi Wei, Guanhong Xu, Yong Sun, Qin Hu, Yao Cen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Inspired by the intrinsic catalytic properties of alkaline phosphatase (ALP) and tyrosinase (TYR) as well as the fluorogenic reaction between levodopa and resorcinol, a ratiometric fluorescent probe based on the CdTe/CdS/ZnS/SiO〈sub〉2〈/sub〉 QDs for visual monitoring the activity of ALP was developed. Phosphotyrosine was catalyzed into tyrosine by ALP, and then tyrosine was catalyzed into levodopa by TYR. Carboxyazamonardine, the reactive product of levodopa and resorcinol, gave rise to a strong blue fluorescence at 470 nm and quenched the red fluorescence of CdTe/CdS/ZnS/SiO〈sub〉2〈/sub〉 QDs at 620 nm due to their inner filter effect. Thus, the resulting ratiometric fluorescence acted as the signal output for quantitative ALP detection, accompanying with the fluorescence color changing from red to purple and finally blue for semiquantitative ALP detection. A good linear relationship was obtained ranging from 0.08-500 U L〈sup〉-1〈/sup〉 with the detection limit of 0.02 U L〈sup〉-1〈/sup〉. Moreover, the probe was successfully applied to monitoring ALP activity in human serum samples without any pretreatment, and also used to screen ALP inhibitors. These results suggested that the developed method offered a highly sensitive and promising analytical platform for ALP in clinical diagnostics and paved a new way for monitoring enzymes activity visually for point-of-care diagnosis.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 309〈/p〉 〈p〉Author(s): Chen Wang, Yu Chen, Zhizhong Xu, Binbin Chen, Yan Zhang, Xue Yi, Jinming Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, an innovative drug delivery system based on cyclic RGD-modified (as the targeting agent) and doxorubicin-loaded graphene quantum dots (R–GQDs@DOX) was fabricated for chemo-photothermal combination therapy. These tasks include drug loading capacity, photothermal efficiency, cellular uptake and combination therapeutic effect of R–GQDs@DOX. The structure of R–GQDs@DOX was characterized by FT-IR spectrum, UV–vis spectrum and AFM. The results indicated that the doxorubicin (DOX) could be loaded onto graphene quantum dots (GQDs) via van der Waals interaction (π–π stacking) and the drug loading capacity was 96.6 % (〈em〉wt〈/em〉). The R–GQDs@DOX not only showed obvious pH-responsive release of DOX, but also exhibited great photothermal efficacy for cancer cells. The fluorescence intensity indicated that R–GQDs@DOX was effectively taken up by SK–mel–5 and H460 cells. The combination of chemotherapy and photothermal therapy could more effectively inhibit growth of tumor cells, compared to photothermal therapy or chemotherapy alone.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520300794-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Zhiheng Ma, Tongwei Yuan, Yu Fan, Luyu Wang, Zhiming Duan, Wei Du, Dan Zhang, Jiaqiang Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As one of the BTEX (benzene, toluene, ethylbenzene, xylene) from living environment, benzene has the greatest carcinogenic, anesthetic and neurotoxic effects. At the same time, due to its chemical inertness and nonpolar characteristics, benzene is also the most difficult to detect in BTEX. Herein, based on QCM (quartz crystal microbalance) platform, MOF-14, a metal-organic framework, is first employed to detect benzene vapor by the host − guest interaction of MOF with benzene molecule, as well as Lewis acid-base interaction. By comparing with other three types of MOF materials, it was found that the effect of the ligand on the adsorption is greater than that of the metal point of junction. On the other hand, the different steric hindrance effects in BTEX restrict their adsorption capacity. Thus, the MOF-14 modified QCM sensor exhibits high sensing performance to benzene vapor with a detection limit at the level of 150 ppb. Our studies also indicate that the sensor shows good selectivity to oppose various kinds of interfering gases. Even toluene has a structure similar to that of benzene, it also can be distinguished. And the measurements on repeatability and long-term stability are both approved for the excellent reliability of the MOF-14 modified QCM sensor. By using computational simulation, we explored that why benzene and toluene can be distinguished by MOF-14 modified QCM sensor. This work extended the usages of MOF based QCM for high performance benzene sensing.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 309〈/p〉 〈p〉Author(s): Yujiao Sun, Hui Jin, Xiaowen Jiang, Rijun Gui〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Novel two-dimensional (2D) metal-organic frameworks (MOF) were one-pot prepared by solvothermal reaction, using copper nitrate and 4,4’,4’’,4’’’-(porphine-5,10,15,20-tetrayl)tetrakis benzoic acid as precursors and thionine (TH) as the doping component. Black phosphorus nanosheets (BPNSs) were prepared by liquid-phase exfoliation of bulk crystals and were adhered to TH-doped 2D MOF (TH/Cu-MOF) to produce BPNSs/TH/Cu-MOF complex. The complex was drop-casted on glassy carbon electrode (GCE) to construct BPNSs/TH/Cu-MOF/GCE, followed by combining ferrocene (Fc)-labeled single-strand DNA aptamer to form aptamer-BPNSs/TH/Cu-MOF nanohybrid on GCE. The formation process of nanohybrid was characterized and experiment conditions were optimized. Under optimal conditions, the aptamer-BPNSs/TH/Cu-MOF/GCE platform served as a smart ratiometric electrochemical aptasensor that can accurately capture and detect microRNA (miR3123). With increase of miR3123 concentration (〈strong〉〈em〉C〈/em〉〈/strong〉〈sub〉miR3123〈/sub〉), the redox peak current of Fc (〈strong〉I〈/strong〉〈sub〉Fc〈/sub〉) decreased, because special combination of Fc-aptamer with miR3123 led to Fc away from GCE surface. TH was doped into 2D MOF and its peak current (〈strong〉I〈/strong〉〈sub〉TH〈/sub〉) had negligible changes. TH and Fc acted as reference signal and response signal, respectively. There is a plotted linear relationship between (〈strong〉I〈/strong〉〈sub〉Fc〈/sub〉/〈strong〉I〈/strong〉〈sub〉TH〈/sub〉) and logarithm of 〈strong〉〈em〉C〈/em〉〈/strong〉〈sub〉miR3123〈/sub〉 in the range from 2 pM to 2 μM, together with a low limit of detection of 0.3 pM. The aptasensor had high sensitivity, selectivity and stability, and was applied to accurate detection of miR3123 in practical samples, showing high practicability.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520301246-ga1.jpg" width="271" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 22 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Anran Gao, Yi Wang, Dongwei Zhang, Yunqian He, Lei Zhang, Yanxiang Liu, Yuelin Wang, Haifeng Song, Tie Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we report the real-time, ultrasensitive, reproducible detection of volatile odorant molecules emitted by human based on free-standing silicon nanowire (SiNW) array functionalized with 〈em〉Anopheles gambiae〈/em〉 odorant binding protein (〈em〉Ag〈/em〉OBP). Highly responsive SiNW array was fabricated with a novel low-cost top-down fabrication approach. The free-standing and triangular cross sectional structure allowed efficient sensing of 〈em〉Ag〈/em〉OBP conformational change induced by odorant binding. The resulting bioelectronic nose (B-nose) possessed high sensitivity down to several ppb, and outstanding size and functional group selectivity. The device showed reproducible and long-lasting performances. We also demonstrated the multiplex detection of various odorants with a sensor array functionalized with three different 〈em〉Ag〈/em〉OBPs. The 〈em〉Ag〈/em〉OBP-SiNW B-nose reported herein provides a powerful and effective platform for future development of multiplexed human body odor sensor arrays.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 309〈/p〉 〈p〉Author(s): Tinnlea Uen, Keiichiro Kushiro, Hiroshi Hibino, Madoka Takai〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electrochemical biosensors have been widely applied to elucidate various information on pharmaceutically important neurotransmitters such as dopamine (DA). However, the biofouling of electrodes has been a critical issue for electrochemical measurements performed in physiological environments. In this study, highly biocompatible polymer brush made of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was employed to modify carbon-based sensors to prevent biofouling. The PMPC brushes with thicknesses ranging from 15 to 30 nm on top of glassy carbon surfaces successfully suppressed protein adsorption in serum environments, and the polymer modification remained stable for at least 8 h in such conditions. The PMPC-modified glassy carbon electrode (GCE) achieved a limit of detection (LOD) as low as 1.8 μM for DA, as determined from cyclic voltammetry (CV), which exhibited better performance than the bovine serum albumin (BSA)-coated GCE with a LOD of 3.9 μM. The results from this study open new avenues for drug discovery and pharmacokinetics by enabling carbon-based biosensors to accurately and sensitively detect pharmaceuticals in protein-rich environments for an extensive period of time.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Zhenhe Wang, Wei Chen, Shuang Gu, Jun Wang, Yongwei Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Trunk borers infestation is difficult to detect because larvae always mine inside trees. However, plants volatile organic compounds (PVOCs) usually change markedly after pests damage which provide us an opportunity to identify trunk borers infestation. Herein, a four-element quartz crystal microbalance (QCM) gas sensor array based on molecularly imprinted polymers (MIPs) was reported for the discrimination of 〈em〉Semanotus bifasciatus〈/em〉 (Motschulsky) and 〈em〉Phloeosinus aubei Perris〈/em〉 (Coleoptera: Scolytidae) infested 〈em〉Platycladus orientalis〈/em〉 (L.) Franco trunks. MIPs were prepared using the methacrylic acid (MAA) polymer matrix and four characteristic PVOCs (α-pinene, β-phellandrene, 3-carene and cis-thujopsene) as templates molecules, repectively. The amounts of MIPs dropped on the QCM chips were investigated and optimized according to the sensitivities and response times. Finally, the sensor array was applied to detect PVOCs of 〈em〉P. orientalis〈/em〉 trunks with 〈em〉S. bifasciatus〈/em〉 and 〈em〉P. aubei〈/em〉 infestation, and the response matrix were processed with principal component analysis (PCA) and linear discrimination analysis (LDA) for visualization, and further discrimination was performed by k-nearest neighbor (KNN), probabilistic neural network (PNN) and support vector machine (SVM). SVM exhibited satisfying identification accuracy rates in both calibration set (97.62%) and validation set (93.75%). This study may contribute to gas sensor arrays development in areas of pest control and forest protection.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520301143-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Guanghui Yang, Jinlai Zhao, Shaozhen Yi, Xuejuan Wan, Jiaoning Tang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Conventional fluorescent probes are either easily photobleached or non-biodegradable, which often leads to the unstable fluorescence signal output and long-term biological toxicity. Therefore, the development of novel fluorescent materials with both excellent photostability and biodegradability is of great significance for further broadening their application in numerous research fields. In this work, Nb〈sub〉2〈/sub〉C quantum dots (Nb〈sub〉2〈/sub〉C QDs) with pristine crystallographic structures of Nb〈sub〉2〈/sub〉C MXene phases and surface oxygen-containing species are synthesized by an ultrasound assisted physicochemical exfoliation in tetrapropylammonium hydroxide. Detailed analyses indicate that the Nb〈sub〉2〈/sub〉C QDs not only possess excellent chemical- and photo-stable fluorescence emission but also achieve successful application in fluorescence sensing of heavy metal ions and fluorescence imaging. More importantly, it is confirmed that the Nb〈sub〉2〈/sub〉C QDs present high biocompatibility and unique biodegradation property responsive to human myeloperoxidase, implying the application safety of Nb〈sub〉2〈/sub〉C QDs 〈em〉in vivo〈/em〉. Under the background of ever-growing and stringent requirements for biosafety and technical stability, the chemical- and photo-stability, biocompatibility, biodegradability, and most importantly the promising fluorescence sensing/imaging characteristic of the obtained Nb〈sub〉2〈/sub〉C QDs may argue well for their future applications in environmental monitoring, biomedical diagnosis, visual display, and anti-counterfeiting.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520300824-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 309〈/p〉 〈p〉Author(s): Nicholas J. Goddard, Ruchi Gupta〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report a very simple biosensor based on the direct observation of leaky waveguide (LW) modes as exponentially decaying interference fringes in the reflectivity curve. This phenomenon was only observed when the refractive index contrast between the waveguide and sample was low (0.002–0.005) and the LW was illuminated with a range of angles of incidence simultaneously. The LW acts as a phase object in angle space, resulting in Fresnel diffraction and formation of interference fringes for each waveguide mode. We present theory, a qualitative explanation and a mathematical model governing the formation of these fringes. The binding of an analyte to recognition elements immobilised in the LW changes its refractive index and thus the angular position of the fringes, which provides the biosensing mechanism. The reported LWs comprised a film of polyacrylamide and copolymers on glass slides, and provided high sensitivity, mass manufacturability and simple instrumentation.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 21 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Jaehyun Park, Bumhee Lim, Na Keum Lee, Ji Hye Lee, Kyungkuk Jang, San Won Kang, Suzi Kim, Ikyon Kim, Hyonseok Hwang, Jeeyeon Lee〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Current fluorescent probes for lysosomes have practical limits due to their pH sensitivity, which makes them unsuitable for long-term tracking of lysosomes in live cell imaging. In addition, viscosity probes are also responsive to polarity, which imposes considerable challenges in cellular imaging. Here, we report 〈strong〉IQ-LV〈/strong〉s, which can serve as viscosity sensors at the lysosomal pH. In contrast to the majority of current molecular rotors that exhibit blue and green emission, 〈strong〉IQ-LV〈/strong〉s showed red-shifted emission (∼95 nm) upon increasing the viscosity at pH 4.5. Among the synthesized viscosity sensors, 〈strong〉IQ-LV57〈/strong〉 and 〈strong〉IQ-LV70〈/strong〉 lacking an aromatic ring at R〈sub〉1〈/sub〉 displayed 15-fold and 116-fold enhancement of red-shifted emission, respectively, upon changes in viscosity. They showed negligible polarity dependency, while the pH sensitivity was minimized by tuning R〈sub〉2〈/sub〉 as we envisioned. Our 1D 〈sup〉1〈/sup〉H-NMR titrations along with TCSPC analysis revealed that 〈strong〉IQ-LV〈/strong〉s exhibit two emissions in lysosomes, viscosity-insensitive green emission (〈sup〉+〈/sup〉HA’-IQH〈sup〉+〈/sup〉) and viscosity-sensitive red-shifted emission (A’-IQH〈sup〉+〈/sup〉), which enabled live cell imaging for tracking lysosomes during the autophagy process. In fluorescence confocal imaging, the red emission was enhanced upon the increase in lysosomal viscosity in HeLa and MCF7 cells, and the observed emission from 〈strong〉IQ-LV57〈/strong〉 and 〈strong〉IQ-LV70〈/strong〉 had a longer duration than that of LysoTracker™ Deep Red in time-lapse images of live MCF7 cells. Furthermore, treatment of 〈strong〉IQ-LV37〈/strong〉 in MCF7 cells resulted in increased autophagosomes and autolysosomes during the autophagy process. Further western blot analysis revealed that 〈strong〉IQ-LV37〈/strong〉 and 〈strong〉IQ-LV57〈/strong〉 block the degradation of autophagosomes, serving as autophagy inhibitors.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520301118-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 308〈/p〉 〈p〉Author(s): Qiao Wang, Jinglong Bai, Qiang Hu, Jiaxin Hao, Xu Cheng, Jianpeng Li, Erqing Xie, Yanrong Wang, Xiaojun Pan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉W-doped NiO nanotubes (NTs) were successfully synthesized for efficient sensing of ethanol vapor using a low cost and economical electrospinning method. The response (resistance ratio) of sensor based on 4 % W-NiO NTs to100 ppm ethanol is as high as 40.56 at 200 °C, which is 10 times higher than that of pure NiO sensor. This significant enhancement in sensor response can be attributed to the change in morphology, increase in oxygen vacancies, and the decrease in hole concentration in NiO by W doping. Based on the adsorption and desorption theory of oxygen, we also demonstrated that the atmospheric oxygen content can improve the sensor response and shorten the response time by increasing the amount of adsorbed oxygen.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 20 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical〈/p〉 〈p〉Author(s): Tianchu Gu, Shanyan Mo, Yingqi Mu, Xin Huang, Liming Hu〈/p〉 〈h5〉ABSTRACT〈/h5〉 〈div〉〈p〉Hydrogen peroxide (H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉) is a small molecule of reactive oxygen species, mainly produced by cell mitochondria, which plays an important role in physiological processes. Excess of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 in normal cells could causes a variety of diseases. For that reason, it is very significant to emerge a detection method with high-precision for H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉. Herein, we reported a structurally novel fluorescent probe, 〈em〉para〈/em〉-nitrophenyl oxoacetyl rhodamine (〈strong〉RhB-NIR〈/strong〉) for the detection of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 levels in living cells. The results show that the Stokes shift for 〈strong〉RhB-NIR〈/strong〉 is 140 nm, much larger than those for other reported rodamine derivatives. 〈strong〉RhB-NIR〈/strong〉 shows satisfactory specificity and high sensitivity for the detection of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉. Excellent linear relationship with H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 within a certain concentration range (0 - 10 μM) was displayed, and the limit of detection (LOD) is 61 nM. More importantly, 〈strong〉RhB-NIR〈/strong〉 realized fluorescence imaging of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 in living cells. In addition, 〈strong〉RhB-NIR〈/strong〉 also shows great potential for targeting mitochondria in cell colocalization experiments, in which the Pearson's coefficient is 0.91 using Rhodamine 123 as a reference. This probe will be a promising tool for detecting H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 in the future research.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520300782-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 308〈/p〉 〈p〉Author(s): Xueqing Gao, Jia Liu, Xuming Zhuang, Chunyuan Tian, Feng Luan, Huitao Liu, Yuan Xiong〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Based on the encapsulation of copper nanoclusters (CuNCs) mixed with Al〈sup〉3+〈/sup〉 into a zeolitic imidazole framework-90 (ZIF-90) to form CuNCs-Al〈sup〉3+〈/sup〉/ZIF-90 composites, a novel, simple and sensitive fluorescent sensor was developed to detect adenosine triphosphate (ATP) and then evaluate the freshness of aquatic products by determining the changes in the level of ATP. Encapsulated CuNCs could be released from the ZIF-90 after their addition to ATP, resulting in the fluorescence quenching of this system. Based on this phenomenon, the sensitive detection of ATP was realized with a detection limit of 0.67 μM, and a good linear relationship was observed between the fluorescence quenching ratios of the CuNCs-Al〈sup〉3+〈/sup〉/ZIF-90 composites and ATP in the concentration range from 1 to 2000 μM. Moreover, satisfactory results were obtained when the proposed ATP detection method was applied to real samples to evaluate the freshness of aquatic products.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Schematic illustration of the synthesis CuNCs-Al〈sup〉3+〈/sup〉/ZIF-90 composites for ATP sensing.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520300678-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Beschreibung: 〈p〉Publication date: 1 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 308〈/p〉 〈p〉Author(s): Huan Xu, Anyue Xia, Jie Luo, Mingxuan Gao, Renkuan Liao, Fake Li, Qiu Zhong, Wenqing Zhang, Yang Wang, Jinhui Cui, Weiling Fu, Kai Chang, Mingzhe Gan, Wenbin Jiang, Ming Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Point-of-care quantitative detection of biochemical markers has broad applications in resource-limited settings. However, current challenges including difficulty in sample preparation and limitation in result quantitation make point-of-care detection platforms failed to achieve fully sample-to-answer detection or meet the clinical quantitative demands. Here, we developed a novel point-of-care platform to realize fully sample-to-answer biochemical marker quantitation in whole blood. Our platform integrated a plasma separation module and a detection module. The plasma separation module contained a plasma separation strip could rapidly separate the plasma from whole blood samples by lateral flow. The detection module generated a colorimetric signal which could be quantified by the smartphone ambient light sensor (ALS) in an equipment-free manner. As a proof-of-concept, two hepatobiliary disease-associated markers, total bilirubin (TBil) and direct bilirubin (DBil), were detected from whole blood to quantitative result. The quantitative performance for clinical samples was highly consistent with the well-established clinical chemistry analyzer. Our platform exhibited remarkable advantages of significant portability (〈 40 g), low cost (〈 $5), rapidity (〈 5 min), instrument-free, high sensitivity (〈 1 μM), and accuracy (89.5 % for TBil, 94.7 % for DBil), which showed up a great potential for biochemical markers detection in resource-limited settings.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 308〈/p〉 〈p〉Author(s): Shifen Xu, Linghong Zhan, Chengyi Hong, Xiaomei Chen, Xi Chen, Munetaka Oyama〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Lead ion (Pb(II)) has emerged as a major mussel pollutant in recent decades, thus the development of sensors capable of detecting Pb(II) is of considerable interest. In this work, a novel, rapid, and “turn-on” phosphorescent sensor was developed to monitor Pb(II) using metal-organic framework-5 (MOF-5, Zn〈sub〉4〈/sub〉O(TPA)〈sub〉3〈/sub〉, TPA: terephthalic acid) as a highly selective and sensitive luminescent probe. A mechanism describing the leaching of Zn(II) from Zn〈sub〉4〈/sub〉O complexes and self-assembly of TPA after Pb(II) coordination is proposed for the MOF-5-Pb(II) system. Using enhanced phosphorescence, the sensor displays a wide linear detection range of 0.01−10 μmol/L and a low detection limit of 2 nmol/L for the determination of Pb(II). Moreover, it is noteworthy that when immobilized in a polyethylene glycol (PEG) film, the MOF-5 probe exhibited a visually distinct color change at 1.0 μmol/L Pb(II) under 365 nm UV light. From these results, a test strip was prepared for semi-quantitative analysis of Pb(II) content. Finally, the proposed phosphorescent sensor was successfully utilized to detect Pb(II) content in mussel. This study demonstrates the first MOF-based “turn-on” phosphorescent sensor for monitoring Pb(II), from which future high-performance phosphorescent sensors to determine food pollutants may be developed.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520300800-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 308〈/p〉 〈p〉Author(s): Kaixin Chen, Huan Lu, Gang Li, Jinniu Zhang, Yonghong Tian, Ying Gao, Quanmin Guo, Hongbing Lu, Jianzhi Gao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Different from the dominant method of surface modification of metal oxide sensing materials with noble metals, a simple and low-cost method is developed by using Zn nanoparticles as a surface modifier in this work. The first step involves the fabrication of porous In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanofibers by an electrospinning technique, and then Zn nanoparticles decorated In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanofibers are constructed by a simple thermal evaporation method. An increase in surface 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈msubsup〉〈mtext〉O〈/mtext〉〈mn〉2〈/mn〉〈mo〉-〈/mo〉〈/msubsup〉〈/math〉 species absorbing capability and a decrease in sensor resistance are observed by surface modification of In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanofibers with Zn nanoparticles. In comparison with pure In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanofibers, this kind of Zn–In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 composite nanofibers display higher response and better selectivity to NO〈sub〉2〈/sub〉. The response of Zn–In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanofibers is up to 130.00–5 ppm NO〈sub〉2〈/sub〉 at 50 °C, which is 13.7 times higher than that of pure In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉. From our perspective, the improved NO〈sub〉2〈/sub〉 sensing performances of Zn–In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 composite nanofibers are mainly attributed to the enhanced resistance modulation because of the formation of ohmic contacts between Zn nanoparticles and In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanoparticles.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Highly sensitive NO〈sub〉2〈/sub〉 sensor was constructed using porous In〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanofibers functionalized with metal Zn nanoparticles.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925400520300630-ga1.jpg" width="264" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Beschreibung: 〈p〉Publication date: 1 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 308〈/p〉 〈p〉Author(s): Sze Shin Low, Yixin Pan, Daizong Ji, Yaru Li, Yanli Lu, Yan He, Qingmei Chen, Qingjun Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Circulating microRNAs (miRNAs) are effective cancer biomarkers that are highly stable in body fluids enabling noninvasive detection. Portable, low-cost and efficient biosensing systems is crucial for early on-site diagnosis, especially in resource-limited settings. Present work deals with the development of a smartphone-based biosensing system for electrochemical detection of circulating microRNA-21 (miR-21) biomarker in saliva as a proof-of-concept. The smartphone-based biosensing system composed of a disposable screen-printed biosensor modified with reduced graphene oxide/gold (rGO/Au) composite, a circuit board for detection and a Bluetooth-enabled smartphone equipped with specially designed Android application. The hybridization between miR-21 target and ssDNA probe on the rGO/Au-modified electrode resulted in the decrease in peak current with increase in miR-21 target concentration. The smartphone-based biosensing system showed comparable performance with commercial electrochemical workstation, for miR-21 detection in the concentration range of 1 × 10〈sup〉−4〈/sup〉 M to 1 × 10〈sup〉-12〈/sup〉 M with correlation coefficient (r〈sup〉2〈/sup〉) of 0.99. In addition to good selectivity in discriminating mismatched and non-target sequences, the biosensing system also showed acceptable recovery rate ranging from 96.2%–107.2 % in spiked artificial saliva. The smartphone-based biosensing system is envisioned to be able to realize rapid and highly sensitive detection of circulating miRNA biomarker in body fluid for point-of-care testing in remote areas.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 308〈/p〉 〈p〉Author(s): Da Meng, Shendan Zhang, Tiju Thomas, Ruiyang Zhao, Ying Shi, Fengdong Qu, Minghui Yang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, a novel fuel cell-type methanol gas sensor based on platinized mesoporous titanium nitride is fabricated. Mesoporous TiN, synthesized from ammonolysis of Zn-containing oxide precursor, is utilized as a support for platinum for both anode and cathode. Its performance is compared to that of Vulcan XC-72R carbon blacks. Hot press method is used for the fabrication of the sensor device. The results for methanol gas detection at room temperature reveal that Pt/TiN sensor has enhanced sensitivity. The response current towards 50 ppm methanol reaches 9.68 μA, which is ∼20 times higher than that of Pt/C sensor (0.41 μA). The Pt/TiN sensor also exhibits excellent repeatability, selectivity and long-term stability. This work reveals the potential of titanium nitride as support materials for gas sensing technologies.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 308〈/p〉 〈p〉Author(s): Yong Kyoung Yoo, Gangeun Kim, Dongsung Park, Jinsik Kim, YoungSoo Kim, Hye Yun Kim, Seung Hoon Yang, Jeong Hoon Lee, Kyo Seon Hwang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Amyloid-β (Aβ) is a peptide that is produced in the brain and carried across the blood brain barrier to the blood. It is an important biomarker for the blood-based diagnosis of early stage Alzheimer's disease (AD). However, the challenges of using blood Aβ are that there are several isoforms of the peptide and that the difference in concentration of the peptide in the blood between AD patient and normal individual is extremely low. Here, we developed interdigitated microelectrodes (IMEs) as an impedance biosensor for the blood-based Aβ detection using gold nanoparticles (AuNPs) sandwich assay. It provided logarithmically linear sensitivity and enhancements in the detection limits of approximately 2.87-fold and 74.84 %, respectively. We prepared mouse plasma sample from the blood of double-mutated APP/PS1 transgenic (TG) and wild-type (WT) mouse group, and AD diagnostic ability was tested by Aβ detection in the plasma samples. Our results showed that AuNPs sandwich assay assisted Aβ detection successfully discriminated TG and WT mouse groups. Thus, with this sensing system, we detected Aβ with high sensitivity and selectivity. This Aβ sensing system with AuNPs sandwich assay could lead to a significant advance in human blood sample based clinical diagnosis.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 308〈/p〉 〈p〉Author(s): Songlin Liu, Hao Ma, Jinyu Zhu, Xiao Xia Han, Bing Zhao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Protein S-nitrosylation is an important post-translational modification, which has important effect on protein functions and is relevant to various diseases. For quantification of the S-nitrosated proteins, it is still challenging to establish a detection method in combination of fast and one-step determination, highly sensitivity and accuracy. Here, we develop a label-free, direct detection method for S-nitrosated proteins based on resonance Raman scattering of ferrous cytochrome c. The laser source of the Raman spectrometer is utilized both for inducing NO leakage and for Raman scattering excitation. The heme ligation alteration and oxidation enable fast quantification of the released NO by the resonance Raman spectroscopy of the cytochrome c. All the results shown in this study demonstrate the great potential of the proposed method for fast, sensitive and reliable assessment of total S-nitrosated proteins in the clinical applications.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Sensors and Actuators B: Chemical, Volume 308〈/p〉 〈p〉Author(s): Guojun Weng, Yao Feng, Jing Zhao, Jianjun Li, Jian Zhu, Junwu Zhao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we developed a simple and sensitive surface-enhanced Raman scattering (SERS) technique for the detection of choline in infant formulas based on a filter-based flexible substrate. The flexible substrate with excellent SERS activity and reproducibility was fabricated using a syringe filter and Ag triangular nanoplates. The Raman marker, 3-mercaptophenylboronic acid, was oxidised to 3-hydroxythiophenol in the presence of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉, which caused a decrease in the SERS peak intensity ratio (I〈sub〉1021 cm〈/sub〉〈sup〉−1〈/sup〉: I〈sub〉996 cm〈/sub〉〈sup〉−1〈/sup〉). Utilising the enhanced flexible substrate, a quantitative detection method for H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 was developed. Additionally, choline could be hydrolysed by choline oxidase to generate betaine and H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉. Thus, the SERS method was successfully applied to detect choline in the concentration range of 10〈sup〉-3〈/sup〉–10〈sup〉-7〈/sup〉 M with a beneficial limit of detection as low as 8.36 nM. Importantly, the recovery of choline from infant formula milk powder was approximately 99 %. The excellent performance of the flexible substrate-based SERS method demonstrated its potential for application in H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉-generated oxidase-based biosensing.〈/p〉〈/div〉