bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Alternating Current Sensors, Memories and Displays with Ferroelectric Sound
Authors: Park Cheolmin 
Published: May 2020

Visualization of human senses has been of great interest for developing an emerging interactive display that can artificially stimulate synesthesia with numerous unprecedented applications. Especially, visualization of various daily sound and music in a form of flexible thin film devices can be a great challenge. In this presentation, we first present flexible artificial synesthesia devices that visualize continuous and complicated sounds [1]. The device is made of a thin composite film of a piezoelectric polymer for sound generation and inorganic electroluminescence (EL) microparticles for direct visualization of input sound signals. Field-induced EL of the microparticles in the device depends upon the source sound wave, making their EL synchronized with sound arising from the piezoelectric actuation. We also demonstrate that piezo and ferroelectric sound is capable of sensing, monitoring, and storing the information of various liquids. Our platform utilises sound arising from liquid-interactive ferroelectric actuation, which is dependent upon the polarity of the liquid [2]. Liquid-interactive ferroelectric sound (LIFS) is successfully developed when a liquid droplet is placed on a ferroelectric polymer layer across two in-plane electrodes underneath the ferroelectric layer under an external in-plane AC field. An AC field built up vertically between one of the electrodes and the liquid results in ferroelectric vibration of the device, leading to sound. The sound pressure level (SPL) of the device depends upon the polarity of the liquid, allowing for facile liquid sensing and identification. More importantly, as the SPL arising from LIFS of a liquid is correlated with non-volatile remnant polarisation of the ferroelectric layer, the information of a liquid is readily stored and retrieved even after the liquid is removed, resulting in a sensing memory of the liquid. By programming different LIFSs on a thin film pad, we can also identify the 2D position of a liquid droplet on the pad. Moreover, our device successfully monitored the flow of a human serum liquid passing through channels with their diameters ranging from millimetres to tens of microns and determined its velocity. Mechanically flexible and optically transparent tube-type LIFS AC devices allow for in situ analysis of the flow of a liquid in terms of SPL.
References:
[1] J. S. Kim, C. Park et al. Nano Energy 59, 773 (2019)
[2] J. S. Kim, C. Park et al. Nat. Comm. 10, 3575 (2019)
Improvement in NO2 Gas Sensing Performance Using Igzo Film Sensor
Authors: Eadi Sunil Babu , Jeong Jun-Kyo , Song Hyeong-Sub , Lee Ga-Won , Lee Hi-Deok 
Published: May 2020

Nitrogen dioxide (NO2) and many other nitrogen oxides species (NOx) have an adverse health effect on human health. Exposure to these gases for a long time can alter the lung function as well as other respiratory conditions. Globally, it is estimated that 13% of children’s under 1-18 years have a new asthma related respiratory problem due to NO2 gas pollution [1]. Further, NO2 related health effect occurs where the concentration of NO2 are higher than 21 ppb according to WHO guidelines. Therefore, detection and monitoring of NO2 gas are very essential.
In this study, Indium-Gallium-Zinc-Oxide (IGZO) films are grown using magnetron sputtering process for the detection NO2 gas. The IGZO films with a thickness of 50 nm were deposited on interdigitated electrode substrates in IGZO with 2:2:7 ratios sputtering target and annealed at 300 °C for 1 hr in O2 atmosphere. The sensor characteristics were studied at room temperature and higher working temperatures in NO2 environment with various concentrations. The sensor response (Rair/Rgas) of 1114 % was obtained for 100ppm NO2 concentration at 150 °C operating temperature as shown in Fig.1. Further to investigate the temperature effect on sensor properties, the sensor was annealed at 400 and 500 °C and also the selectivity of the sensor were examined with various gases.
Reference :
1. P. Achakulwisut, M. Brauer, P. Hystad, S. C. Anenberg, Global, national, and urban burdens of paediatric asthma incidence attributable to ambient NO₂ pollution: estimates from global datasets, Lancet Planet Health 3, 166–78, (2019).

Acknowledgment

This research was supported by the MOTIE (Ministry of Trade, Industry & Energy (10048536) and the KSRC (Korea Semiconductor Research Consortium) support program for the development of future semiconductor devices. This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT & Future Planning(NRF-2015M3A7B7045563).

Figure 1
Ultrasensitive Electrochemical Dnazyme Based Sensing Platform for Clinical Detection of Uropathogenic Escherichia coli
Authors: Pandey Richa , Chang Dingran , Li Yingfu , Soleymani Leyla 
Published: May 2020

Urinary tract infections (UTIs) are one of the most ubiquitous bacterial infection diseases affecting half of the global population at least once in their lifetime. Given the occurrence of the false positive result in Dipstics and the time-consuming identification of bacteria using culturing method to detect UroPathogenic Escherichia coli (UPEC), there is the need for a point-of-care diagnostic platform that is reliable, sensitive, specific, cost-effective, fast and easy to use. With the advent electrochemical methods coupled with the specific biorecognition elements, the detection of any biomarker has become possible with one touch. Among many biorecognition molecules, DNAzymes are gaining attention due to their robustness, stability, specificity, and the ease of selection without prior knowledge of the biomarker. Their structure switching and functionality (RNA cleaving) can be utilized with redox active species (like methylene blue) to design highly sensitive and selective electrochemical assays for pathogen detection.
In this work, we have developed a dual signaling electrochemical DNAzyme based platform for specific and sensitive detection of Escherichia coli (E.coli) in UTI patient urine samples. The two on-chip working electrodes named as release channel and capture channel are integrated with DNAzyme-redox barcode and DNA probe respectively. In the presence of the bacterial target the DNAzyme catalyzes the cleavage of the redox DNA barcode in the release channel, which is subsequently translated into a redox signal upon hybridization with the probe on the capture channel. The differential signal generated by the two channels in the sensor demonstrated the sensitive detection of 10 CFU for E.coli in buffer and urine. Additionally, the sensor specifically detected E. coli in the presence of a panel of other gram positive and negative bacteria. Clinical validation of the assay was performed using 40 E.coli+ and E.coli- patient urine delineating a clinical sensitivity of 100% and specificity of 78% in a 30 minute testing time. This cost effective, reagent-free, time-efficient, and amplification-free electrochemical assay is suitable for detecting a wide range of pathogens, also alleviates the additional knowledge requirement of the biomarker as compared to other protein and aptamer-based assay. With the advancement in the chip fabrication and microfluidics, this assay can also be multiplexed with other pathogen for simultaneous detection of multiple pathogens in a single urine sample.
Probing DNA Stability in High Electric Fields: Electrochemical Melting Analysis
Authors: West Ryan M 
Published: May 2020

Here we present our results on the electric field-induced melting of surface-bound DNA (i.e. electrochemical melting). In particular, we examine the effects of DNA-binding compounds, such as cisplatin, on the stability of DNA within high electric fields. Cisplatin is an anticancer drug that has been used to successfully treat testicular, ovarian, and bladder cancers, among others [1]. It crosslinks DNA between the N7 atoms of purine bases, resulting in changes in structure and stability, ultimately interfering with vital cellular processes in vivo. Self-assembled monolayers (SAMs) of thiol-modified oligonucleotides on gold electrodes provide selective and sensitive interfaces for the development of chemical and biological sensors [2]. While many transduction mechanisms have been utilized (including electrochemical, optical, and gravimetric) and many analytes targeted (e.g. small DNA-binding molecules, heavy metals, and specific DNA sequences), the unique steric and electrostatic environment of the crowded DNA in the electrical double-layer complicates the behavior of these biosensors [3]. Electrical potentials applied at the DNA-SAM have been shown to modulate the behavior of these monolayers [4]. Here, we utilize the electric field-effect to induce melting of the bound double-stranded DNA, and we monitor the kinetics of the melting process using square wave voltammetry [5]. We find that the effect of cisplatin on the melting behavior depends on the method used to the prepare the monolayer, in particular the surface-coverage and heterogeneity of the resulting layers. In some instances, cisplatin results in a stabilization of the DNA-SAM and in others a destabilization. Significant differences in the resulting melting curves imply that the mode of cisplatin-DNA binding varies depending on the preparation method. This methodology has the potential of (1) providing an electrochemical approach for studying the interaction between DNA and small molecules, and (2) providing a method for indirectly assessing the heterogeneity of DNA-SAMs via electrochemical melting in the presence of cross-linking agents.
[1] R. A. Alderden, M. D. Hall, T. W. Hambley, The discovery and development of cisplatin, Journal of chemical education, 83(5), (2006) 728.
[2] J. J. Gooding and N. Darwish, The rise of self‐assembled monolayers for fabricating electrochemical biosensors—an interfacial perspective, The Chemical Record, 12, (2012) 92.
[3] Gong and R. Levicky, DNA surface hybridization regimes, Proceedings of the National Academy of Sciences, 105, (2008) 5301.
[4] U. Rant, K. Arinaga, S. Fujita, N. Yokoyama, G. Abstreiter, M. Tornow, Electrical manipulation of oligonucleotides grafted to charged surfaces, Organic & Biomolecular Chemistry
4 (2006) 3448.
[5] D. Ho, W. Hetrick, N. Le, A. Chin, R. M. West, Electric Field Induced DNA Melting with Detection by Square Wave Voltammetry, Journal of the Electrochemical Society,
166, (2019) B236.
Binary MnO2/Co3O4 @ Well-aligned Electrospun Carbon Nanofibers for Sensitive, Nonenzymatic Glucose Sensing
Authors: Wei Jianjun , Yin Ziyu , Zeng Xinping , Allado Kokougan , Ji Zuowei , Sheardy Alex , Arvapalli Durga 
Published: May 2020

A binary metal oxide composite, manganese oxide/cobalt oxide (MnO2
/Co3O4), on a well-aligned electrospun carbon nanofibers (MnO2/Co3O4@ECNFs) mat was synthesized via a simple one-step template-free electrodeposition process at a constant low-current (60 μA) for hours. The MnO2/Co3O4@ECNFs nanocomposite mat show excellent electrocatalytic activity towards sensitive and selective non-enzymatic glucose sensing. The MnO2/Co3O4@ECNFs nanocomposite were tested and characterized thoroughly by high resolution imaging and spectroscopic techniques. The results reveal that the binary metal oxides are uniformly deposited on the well-aligned ECNFs mat with high porosity, effective interconnectivity and large number of extended conducting channels. The electrochemical impedance spectroscopy (EIS) of the nanocomposite mat electrode show very good conductivity in 0.1 M KCl containing 5 mM [Fe(CN)6]3-/4-. The electrocatalytic activity of as-prepared MnO2/Co3O4@ECNFs for oxidation of glucose were performed by cyclic voltammetry (CV) and chronoamperometry (CA); and the experimental results demonstrate a superior sensing performance for glucose detection, including a rapid response (5 seconds), a wide dynamic range (up to 10.9 mM), excellent sensitivity of 973.91 μA mM-1 cm-2 and a detection limit of 0.02 μM (S/N=3) with satisfactory selectivity, reproducibility and stability. The plausible reactions involved for the electrocatalytic oxidation of glucose by the binary metal oxides are as follows.1

2Co02
+ C6H1206
(glucose) -> 2Co00H + C6H1006
(gluconolactone) (1)
2Mn0
2 + C6H1206
(glucose) -> 2Mn00H + C6H1006
(gluconolactone) (2)
Finally, the nanocomposite electrode was tested in glucose spiked human serum samples. The recovery rates of a series of standard glucose solutions are nearly 100%, suggesting the excellent performance and potential towards development of a nonenzymatic glucose biosensor for practical applications.

Reference

1. Han, L.; Yang, D.-P.; Liu, A., Leaf-Templated Synthesis of 3d Hierarchical Porous Cobalt Oxide Nanostructure as Direct Electrochemical Biosensing Interface with Enhanced Electrocatalysis. Biosensors and Bioelectronics
2015, 63, 145-152.
Superhydrophobic Hierarchical Porous Divinylbenzene Polymer for BTEX Sensing and Toluene/Water Selective Detection
Authors: Chen Yang , Xu Jiaqiang , Kong Jiawei , Shen Bing 
Published: May 2020

As shown in the Fig.1, this work reports a superhydrophobic divinylbenzene polymer with hierarchical porous structure as sensing material to modify the quartz crystal microbalance (QCM) to detect benzene, toluene, ethylbenzene, and xylene (BTEX) vapor. Notably, sensing results toward toluene vapor in different relative humidities indicates that this superhydrophobic polymer has favorable toluene/water selective detection performance. Besides, the limit of detection toward toluene is lower than 1 ppm.
Introduction
As typical hazardous chemicals, benzene series, especially BTEX, are easily dispersed in the air because of their extremely easy volatile nature. BTEX can paralyze the central nervous system of humans, causing neurasthenia, liver disease, and even cancer. Therefore, using gas sensor for real-time detection of BTEX is necessary.
Compared with other sensors, QCM sensor has the advantages of low cost and working at room temperature. By modifying sensitive materials on the surface of QCM, the target gas can be adsorbed and the surface quality of QCM changes. This change can be further transformed into frequency shift by Sauerbrey equation, and recorded by computer. Based on QCM platform, some benzene sensors have been reported. For example, Kumar et al. used tetra-tert-butyl copper phthalocyanine to realize the sensing of BTEX. The response to 500 ppm of toluene can reach 60 Hz. But none of these reports discussed the effect of humidity on the sensor response. Our research group detected the BTEX vapor via using superhydrophobic polyoctadecylsiloxane (PODS) based on QCM. Besides, PODS can stably detect toluene vapor under different relative humidities. However, when the concentration of toluene is 20 ppm, the response value is only about 7 Hz. It is indicating that the detection limit of PODS to toluene cannot be less than 20 ppm.

Figure 1
(Invited) Electrochemistry Confined Nanopore: Design and Application in Single Molecule Sensing
Authors: Long Yi-Tao 
Published: May 2020

Single-molecule sensing is key to deep understanding of elemental biological processes and complex bioreactions. Nanopore-based single-molecule method, a unique technique based on the modulation in ionic current, provides a high temporal-spatial resolution for single molecule sensing. To achieve a high selectivity and sensitivity of biological nanopore, the modification of specific group presenting in the whole region of Aerolysin nanopore was successfully designed, and every single molecule forms a whole sensing interface.1,2 As a reasonable model, a single membrane protein which is assembled from several monomers is regarded as a single molecule interface Therefore, the side chain of every single amino acid groups could be designed respectively by single site mutation.3 The single molecule interface has been achieved in biological nanopore sensors. A single membrane protein molecule could be regarded as a single molecule interface. Single molecule interface facilities the design of single sensing zone which ensures high spatial- and temporal resolution towards single molecule analysis. The single-site modification along the single molecule interface manipulates each site of interface for the precise responses which meet the multiple sensing requirement. More importantly, single molecule interface provides a confinement for the single molecule reaction which offers the possibility to study reaction kinetics in high temporal resolution. These advances provide a new concept in designing advanced sensors. Moreover, by combining with other single molecule methods such as fluorescence or plasmonic technology, it is possible to construct an integrated single molecule interface for multi-element readouts, which is expected to further provide the rich structural information of a single molecule.

Figure 1. Single-molecule music. A single-molecule interface likes a tuba. As each molecule flows through the single-molecule interface, one can control the ‘button’ along the ‘tuba’ to organize a beautiful rhythm for single-molecule music.

Keywords: Nanopore; Aerolysin nanopore, Single biomolecule interface, Site Mutation, Single molecule sensing.

References:

[1] Y. L. Ying, C Chao, Y. X. Hu and Y. T. Long*. Natl. Sci. Rev., 2018, 5 (4), 450-452.
[2] Y. L. Ying and Y. T. Long*. J. Am. Chem. Soc., 2019, 141 (15), 15720-15729.
[3] Y. Q. Wang, C Cao, Y. L. Ying, S Li, M. B Wang, J Huang, Y. T. Long*. ACS Sens., 2018, 3 (4), 779–783.

Figure 1
Catechol-O-Methyl Transferase (COMT) Activity Detection Using Metal OXIDE Electrodes
Authors: Göbel Gero , Lisdat Fred 
Published: May 2020

Parkinson’s disease is one of the most frequent diseases of the central nervous system with rather severe consequences for patients. Since the disorder can not be cured, the dopamine level in the brain needs to adjusted. Here several key enzymes of the dopamine metabolism [e. g. catechol-O-methyl transferase (COMT)] are targets for administered drugs. However, the efficiency of the treatment is decreasing with time. Consequently a monitoring of the actual activity of these enezmyes and an adjustment of the pharmaceutical treatment would be beneficial to prolong the treatment effects.
In this study, an electrochemical approach is introduced for activity determination of the COMT enzyme. As detection method differential pulse voltammetry (DPV) has been used exploiting an improved signal to noise ratio. Activity determination is based on the selective detection of one substance in the reaction scheme of the enzyme – here dopamine. As electrode material fluorine doped tin oxide (FTO) has been elucidated since it is characterized by a clear discrimination between the substrate and the product of the COMT [1]. This can be achieved without additional layers on top of the electrode. The response is characterized by a rather high stability of the dopamine signal during consecutive measurements and a linear dependency of the peak currents on the dopamine concentration in the range of the maximum reaction rate of COMT [2]. Furthermore it has been detected that redox active interferences such as ascorbic acid do not disturb the analysis.
Despite these advantageous results, it has been found that the electrochemical dopamine oxidation in the complete activity assay is influenced by each of the added essential assay components, even though none of the added components reveal a current signal at the FTO electrode itself. After adjusting the potential range of the electrochemical analysis and the solution composition, these effects can be circumvented.
Consequently, by following the dopamine concentrations during COMT action, it can be shown that the
activity of the enzyme can be detected by using DPV at a FTO electrode. Experiments with different amounts of the enzyme further demonstrate that activity quantification is feasible.
References
[1] G. Göbel, A. Talke, F. Lisdat, Electroanalysis, 2018, Vol. 30 (2), p. 225-229
[2] G. Göbel, A. Talke, U. Ahnert, F. Lisdat, ChemElectroChem, 2019, Vol. 6 (17)
DT-Diaphorase As a Promising Catalytic Label for Rapid and Sensitive Immunosensors
Authors: Yang Haesik 
Published: May 2020

The most common enzyme labels in biosensors are alkaline phosphatase (ALP) and horseradish peroxidase (HRP), which, however, have some limitations for use in electrochemical immunosensors. DT-diaphorase (DT-D) is a redox enzyme that catalyzes a two-electron reduction of quinone in the presence of NADH or NADPH. Importantly, DT-D from Bacillus stearothermophilus (EC 1.6.99.-) has a low molecular weight (30 kDa) and high thermal and long-term stability. Nevertheless, DT-D has never been employed as a catalytic label in biosensors. In this presentation, we report that DT-D can be used as a bifunctional enzyme label for rapid and sensitive electrochemical immunosensors: DT-D can convert an electrochemically inactive substrate into an electrochemically active product and DT-D can participate in electrochemical-chemical (EC) and electrochemical-enzymatic (EN) redox cycling induced by the product. We found that DT-D has high catalytic activities for nitroso reduction, phosphoester hydrolysis, and carboxyl ester hydrolysis as well as quinone reduction in the presence of NADH. 4-Nitroso-1-naphthol, 1-amino-2-naphthyl phosphate, and 4-aminonaphthalene-1-yl acetate are used as electrochemically inactive substrates for corresponding enzymatic reactions, which are converted into electrochemically active aminohydroxy-naphthalenes. This combination of DT-D and the substrates allows for high electrochemical signal-to-background ratios, because (i) the catalytic reaction by DT-D is fast, (ii) the electrochemical oxidation of the aminohydroxy-naphthalenes is rapid, even at an indium-tin oxide electrode, and (iii) two redox cycling processes significantly increase the electrochemical signal. The electrochemical immunosensor using DT-D and 4-nitroso-1-naphthol detects parathyroid hormone with a low detection limit of 2 pg/mL, the immunosensor using DT-D and 1-amino-2-naphthyl phosphate detects outer membrane vesicles from Escherichia coli with a detection limit of 8 ng/mL, and the immunosensor using DT-D and 4-aminonaphthalene-1-yl acetate detects thyroid-stimulating hormone with a detection limit of ~2 pg/mL. DT-D may be used as a catalytic label in sensitive and stable bioassays instead of common ALP and HRP.
References
1. P. Nandhakumar, A. M. Ichzan, N.-S. Lee, Y. H. Yoon, S. Ma, S. Kim, H. Yang, ACS Sens. in press.
2. A. Bhatia, P. Nandhakumar, G. Kim, J. Kim, N.-S. Lee, Y. H. Yoon, H. Yang, ACS Sens. 4, 1641 (2019)
3. A. M. Ichzan, S. Lee, C. S. Fang, P. Nandhakumar, H. Ha, J. M. Joo, K. Kim, H. Yang, Anal. Chem. 91, 4680 (2019)
4. P. Nandhakumar, A.-M. J. Haque, N.-S. Lee, Y. H. Yoon, H. Yang, Anal. Chem. 90, 10982 (2018)
5. C. Kang, J. Kang, N.-S. Lee, Y. H. Yoon, H. Yang, Anal. Chem. 89, 7974 (2017)