bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlating Materials Degradation Trends to Electrochemical Indicators in Systematic Long-Term Cycling of Commercial Li-Ion Batteries
Authors: Wittman Reed M , Preger Yuliya , Fresquez Armando , Ivanov Sergei , Chalamala Babu R.
Published: May 2020

In order to improve the operation of Li-ion batteries the long-term performance is the subject of much research. Of particular importance is understanding systematic trends in degradation through a broad range of operating conditions. Over the course of the last few years, researchers at Sandia National Labs have conducted a systematic study of battery cycling behavior. In this study, dozens of commercial NCA (LiNixCoyAl1-x-yO2) and NMC (LiNixMnyCo1-x-yO2) cells were cycled to 80% capacity and end of life across a range of temperatures, discharge rates, and depth of discharge windows. Analysis of both in situelectrochemical data and postmortem materials degradation was done.

During cycling, cell resistance (IR), Electrochemical Impedance Spectroscopy (EIS), and differential capacity (dQ/dV) experiments were conducted periodically. The data from these experiments were used to understand the state of health (SoH) of cycling cells, including SEI formation and Li plating, as well as general mass transport and kinetic properties.

For the postmortem analysis cells in pristine condition, 80% capacity, and end of life were disassembled, and their electrodes were analyzed with X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), and Brunauer-Emmett-Teller Isotherms (BET). These techniques analyzed different aspects of the electrodes’ physical and chemical properties, including Li plating, micro-cracking, SEI layer formation, and phase changes in cathode materials. BET and DSC measurements also provided insight into changes in the degree to which aged electrodes undergo thermal runaway events.

Correlation of the postmortem materials analysis with the in situ electrochemical analysis gave an in-depth understanding of the origins of performance fade during cycling. The scale of this electrochemical and materials evaluation fills in gaps in the literature about battery performance and degradation beyond 80% capacity.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
Characterizing Coupled Transport Phenomena of Large-Format Lithium-Ion Pouch Cells Using Lock-in Thermography and Laser Scanning
Authors: Chu Howie N. , Monroe Charles W.
Published: May 2020

Management of battery systems is difficult due to the variety of physical processes that occur when a battery is put under an electrical load. These processes produce macroscopic side effects, such as stress/strain and temperature evolution, which originate at the electrode level. The electrochemical-thermal-mechanical phenomena in battery cells are highly coupled in applications such as electric vehicles. Because microscopic effects in battery electrodes can propagate into larger length scales such as the cell and pack levels, there are changes on the outside that can be observed.

Contact-free, non-destructive methods for measuring changes in battery temperature and strain could serve as tools to determine a battery’s second-life prospects, and could also aid early fault detection. The lock-in thermography technique has been used to determine faults and locate defects within cells.1 It has also been shown that mechanical stresses can be used to monitor state of health (SOH) and state of charge (SOC).2,3 Laser scanning has also been implemented to generate strain distributions showing local mechanical effects during electrochemical cycling.4

A first step in understanding highly coupled systems is to characterize the individual phenomena in isolation. Figure 1 presents a contour plot that shows the result of a zero-displacement experiment, where the evolution of equilibrium stress within a constrained 3-cell battery pack is measured at various SOCs and at various ambient temperatures. This experiment has shown that thermally induced volume change can contribute as much to mechanical forces within a cell as intercalation/deintercalation stresses. In high-power applications such as electric vehicles, we expect to see consequences from both of these factors. So, we will be developing an experimental set-up that combines the techniques of lock-in thermography and laser scanning to simultaneously capture 2D strain and temperature distributions that arise in response to different current input signals. Data from the individual techniques, plus the combined experiment, can be used to see how a battery’s response changes as a consequence of its thermal and mechanical state, and how the relative contributions of temperature and strain can affect battery operation.

Figure 1
A Self Powered Solid-Liquid Contact Electrification Based Nanosensor for Chemically Enhanced Detection of Catechin
Authors: Chatterjee Subhodeep , Lin Zong-Hong
Published: May 2020

The harvesting of mechanical energy based on triboelectric effect between solid-solid material and utilizing it for chemical sensing, have been proved to be simple, cost effective and robust. However, it suffers from several drawbacks such as surface instability and drift in output voltage due to several environmental factors like humidity. In this study, a self-powered triboelectric nanosensor (TENS) based on chemically enhanced solid-liquid contact electrification has been demonstrated. The TiO2 nanosheet (NS) array, grown over Ti by two-step hydrothermal process is employed as solid triboelectric material. On the other side, volatile organic solvent acetone is utilized as contact liquid to obtain higher triboelectric performance. A periodic contact separation between TiO2 NS and acetone generates a series of contact frequency independent output voltage cycles with long term stability in comparison to solid-solid contact electrification earlier. When TiO2 NS surface is forced to make a full contact with acetone, the ionization of surface groups on the TiO2 NS surface causes TiO2 NS to be fully positively charged, creating a negatively charged electrical double-layer on the contact surface of acetone to maintain the charge neutrality. As the TiO2 NS surface is moving off the acetone solution, the emerging part of its surface remains positively charged, leaving the negative electrical double-layer in the acetone solution. As a result, a potential difference is developed between TiO2 NS and acetone. Thus, it leads to transfer of electrons from ground to Ti electrode until TiO2 NS is entirely emerged from acetone, reaching an equilibrium state. The chemical modification of TiO2 NS surface with catechin promotes enhanced response voltage due to ligand to metal charge transfer complex between Ti molecules and enediol ligands of catechin, exhibiting 1 nM limit of detection(LOD) and wide linear range (1 µM to 100 µM). The output voltage has been chemically enhanced 1.59 times for 10 mM catechin concentration. Therefore, the study not only demonstrates a self-powered cost-effective nano-sensor but also explores the possibility to improve the electrical performance of solid-liquid based contact electrification through surface chemical environment engineering and through utilizing volatile organic solvents as contact liquid.
Contact Electrification of Surface Attached E.coli in Liquids As a Fast-Response Bacterial Sensor
Authors: Lin Zong-Hong , Pao Yu-Ping
Published: May 2020

Bacteria is present everywhere in our daily lives, and bacterial assays have become a topic of constant concern in the world. Common urinary tract pathogenic Escherichia coli (UPEC) which has type 1 pili, easily attaches to the epithelial cells of the human body, causing urinary tract infections, cystitis, or inflammatory bowel disease. Type 1 pili are found in more than 95% of E. coli isolates of intestinal and extraintestinal infections (eg, urine infections). There are many studies on type 1 pili, which are mainly composed of proteins, and the most significant is the terminal fim H protein, which can specifically bind to D-mannose. This research is dedicated to the development of a rapid-responding E. coli sensor that uses mannose to capture bacteria. Based on the principle of contact-electrification, as the E. coli attached to the surface of the sample is in contact with a liquid, the concentration of the bacteria can be detected in a short time by measuring the voltage output. For the first time, a simple, rapid and low-cost E. coli sensor was developed as a triboelectric system.
(Invited) 2D Tellurene for Novel Electronics and Sensors
Authors: Wu Wenzhuo
Published: May 2020

In this talk, I will discuss our recent progress in controllable synthesis of tellurene for electronics and sensor applications. The solution-synthesized tellurene crystals exhibit process-tunable thickness from a monolayer to tens of nanometers, lateral sizes ~ 100 mm, and can be transferred to designer substrates. I will further discuss our findings in 2-D tellurene’s material properties, as well as our efforts in the prototypical device explorations with the acquired fundamental understandings of tellurene’s properties. Our results show that the air-stable tellurene, as an emerging 2-D material, exhibits a plethora of intriguing physical properties appealing for applications in electronics, optoelectronics, energy, sensors, and quantum devices.
Investigation of Highly Sensitive Cadmium Ion Selective FET Sensors with AC Impedance Analysis
Authors: Wang Shin-Li , Hsieh Ching-Yen , Wang Yu-Lin
Published: May 2020

In this study, we developed a cadmium ion selective sensor which can detect cadmium ion in water, in the convenience of home/office. The ion selective membrane (ISM) FET sensor combines novel extended gate FET structure and cadmium ion selective membrane. The AC impedance measurement result is also analyzed in this research. There is an electrode pair on the epoxy substrate. One is the reference electrode (RE) and another one is the extended electrode (EE). Gate voltage is applied on the reference electrode and the extended electrode is connected to the gate of the FET. The voltage change caused by ions will be amplified by the FET. The cadmium ISM is immobilized on the electrode pair. A narrow gap between the two electrodes leads to the high sensitivity and, as well as the high gate voltage. Figure 1 shows the electrical characteristic of Cd-ISFET. From the figure we can find out that as the cadmium ion concentration increases, the drain current will also increase. The response time of the Cd-ISFET sensor only needs 15 minutes and detection limit can reach 10-11M which is comparable with laboratory based instrument like ICP-MS. This Cd-ISFET sensor has high sensitivity (71 mV/ decade [Cd2+]) which is beyond ideal Nernst sensitivity (29 mV /decade [Cd2+]). A portable device is developed in this research and makes the operation method easy, friendly and convenient in contrast with ICP-MS. We first demonstrate the methodology of our sensor and we will apply our sensor on drinking water, tea, Chinese herbal medicine, and milk etc.

Figure 1
(Invited) Electrochemical Energy Harvesters Based on Stress-Composition Coupling in Li Alloys
Authors: Kim Sangtae
Published: May 2020

Efforts to harvest human-induced energies into electricity has garnered a significant amount of research attention, with potential applications in powering wireless sensors or Internet of Things (IoT) devices. Successful integration of energy harvesters into small-scale sensor systems may operate sensors without battery exchange for years or in remote environments where battery charging is not applicable. Energy harvesters may also provide additional efficiency to the overall electric grid, since the amount of generated electricity scales directly with human activities; providing electricity at the peak time and location where electricity is needed the most alleviates the burden from the electric grid.

To realize successful energy harvesters, researchers have developed energy harvesters from different sources such as thermal, vibrational, acoustic or contact electrification-based energies. Many of these types, however, face severe challenges to commercialization due to the limited efficiencies linked to their fundamental working mechanisms. For instance, piezoelectric and triboelectric generators suffer from the mismatch between their natural output frequencies and human motion timescales. The generated electricity from these two types often has current peak widths below 100 msec, making them limited in the human activities timescales of 0.55 Hz[1,2].

In this talk, we develop and demonstrate an electrochemically driven mechanical energy harvesters based on stress-composition coupling in Li binary alloys[3]. We first demonstrate the presence of stress-composition coupling among Li-alloys, by using in situ graphene liquid cell electron microscopy.[3] With the unveiled stress-composition coupling, we demonstrate two distinct device concepts utilizing this stress-composition coupling, with Li
x
Si thin films and yolk-shell nanoparticles[4].

[1] Chun J., Ye B. U., Lee J. W., Choi D., Kang C.-Y., Kim S.-W., Wang Z. L., Baik J. M., “Boosted output performance of triboelectric nanogenerator via electric double layer effect” Nature Communications 7, 12985 2016.

[2] Hwang G.-T., Park H., Lee J.-H., Oh S., Park K.-I., Byun M., Park H., Ahn G., Jeong C. K., No K., Kwon H., Lee S.-G., Joung B., Lee K. J., “Self-powered cardiac pacemaker enabled by flexible single crystalline PMN-PT piezoelectric energy harvester” Advanced Materials 26, 4880 2014.

[3] Seo H., Park J.Y., Chang J.H., Dae K.S., Noh M.S., Kim S.S., Kang C.-Y., Zhao K., Kim S., Yuk J., "Strong stress composition coupling in Lithium alloy nanoparticles" Nature Communications 10, 3428 2019

[4] Kim S., Choi S.J., Zhao K., Yang H., Gobbi G., Zhang S., Li J., “Electrochemically driven mechanical energy harvesting” Nature Communications 7, 10146 2016
(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)
Mining Nanopore Big Data to Reveal the Single Molecule Heterogeneity
Authors: Ying Yi-Lun , Li Xin-Yi , Long Yi-Tao
Published: May 2020

The recent development of nanopore techniques pushes the envelope in precision and complexity to maximize the information content. However, uncovering the interaction and kinetics of single molecules acquires statistical datasets by thousands of single molecule information. 1-2 The challenge still exists from effectively grouping the time-dependent ionic current trace into subpopulations. In this study, we applied the modified Hidden Markov Model to identify the ionic blockage merging inside current noise, which increase the temporal resolution and current resolution for nanopore techniques.3-4 Then, we traced the multi-level current variations inside a blockade event by using Markov Chain Model, which reveals the dynamic kinetics for the conversion of multi-intermediates.5 Since the ions migrate at different frequency inside nanopore, it acts as the smallest sensor to perceive and feedback the non-covalent interaction into the of ionic current frequency. We further employed Hilbert-Huang transform (HHT) to uncover these varied ionic frequencies which buried in the noise of the ionic current traces.6 The HHT-based frequency analysis arises a two-dimension signal from time domain (time and current) into a three-dimension spectrum of energy-frequency-time distribution. The frequency-energy spectrum represents the fingerprint spectra for the characterization of non-covalent interaction due to the interaction between residues inside nanopore and the analyte. The very beginning frequency analysis let us mine more information from the data, which could help to unravel different hierarchical pathways and enables to discovery the subpopulations and hidden kinetic during the dynamic motion of single molecules.

REFERENCES

1. Yi-Lun Ying, and Yi-Tao Long; Nanopore-Based Single-Biomolecule Interfaces: From Information to Knowledge. J. Am Chem. Soc. 2019, 10.1021/jacs.8b11970.

2. R.-J. Yu, Y.-L. Ying, R. Gao, Y.-T. Long, Confined Nanopipette Sensing: From Single Molecules, Single Nanoparticles to Single Cells, Angew. Chem. Inter. Ed., 2019, 10.1002/anie.201803229.

3. J. Zhang, X. Liu, Y.-L. Ying, Z. Gu, F.-N. Meng, Y.-T. Long, High-bandwidth nanopore data analysis by using a modified hidden Markov model, Nanoscale, 2018, 3458-3465.

4. J. Zhang, X. Liu, Z. Hu, Y.-L. Ying, Y.-T. Long, Intelligent identification of multi-level nanopore signatures for accurate detection of cancer biomarkers, Chem. Commun., 2017, 10176-10179.

5. Y.-L. Ying, S. Liu, X. Shi, W. Li, Y. Wan, Y.-T. Long, The Hidden Transition Paths During the Unfolding of Individual Peptides with a Confined Nanopore. 2018, ChemRxiv. https://doi.org/10.26434/chemrxiv.6394925.v1

6. S. Liu, M. Li, M. Li, Y. Wang, Y.-L. Ying, Y.-J. Wan, Y.-T. Long, Measuring a Frequency Spectrum for the Single-Molecule Interactions with A Confined Nanopore, Faraday Discuss., 2018, 210, 97-99.

Figure 1
Implantable Smart Stent with Nanomembrane Soft Sensors for Wireless Monitoring of Hemodynamics
Authors: Herbert Robert , Lim Hyo-Ryoung , Yeo Woon-Hong
Published: May 2020

Cardiovascular diseases, including hypertension and atherosclerosis, account for over 30% of deaths worldwide. To diagnose and monitor these diseases, hemodynamic parameters, such as pressures, flow rates, and flow resistances, are measured. Current measurement techniques include expensive imaging processes and repetitive invasive catheterizations. These methods provide a narrow view of hemodynamics that may fail to capture significant abnormalities and may be inaccurate due to patient discomfort. Continuous monitoring would offer distinct advantages for clinical and research applications. However, implantable hemodynamic sensors are lacking due to stringent mechanical and electrical requirements. Wireless communication through tissue is required for noninvasive monitoring, but narrow blood vessels (<5 mm-diameter) with tortuous geometries prevent the use of conventional rigid electronic components. Additionally, implantable vascular sensors should be compatible with conventional catheter deployment procedures, which require mechanical stability under crimping, sheath introduction, and expansion. The only commercially available implantable sensor is a bulky, rigid package restricted for blood pressure monitoring in larger vessels. Existing research works are severely limited by short wireless communication distances and fragile designs.

Here, we introduce a low-profile, wireless biosensor system comprised of an inductive medical stent and capacitive pressure sensor. The smart stent is designed and fabricated to maximize inductance to achieve functional readout distances, while maintaining its medical purpose. Analytical and experimental study optimizes the stent design for wireless communication via inductive coupling. The low-profile capacitive sensor is fabricated via aerosol jet printing, an additive manufacturing process. The sensor employs a microstructured PDMS layer as the dielectric of a highly flexible parallel-plate structure to achieve high pressure sensitivity (6 fF/mmHg). Experimental study optimizes the printed PDMS structures to maximize sensitivity. The capacitive sensor is integrated with the inductive stent to form an LC circuit with a resonant frequency dependent on pressure. The device is experimentally proven to be readily expandable by balloon catheter to allow for compatibility with existing catheter and stent placement procedures. The low-profile biosensor system is also shown to minimize disruption to normal hemodynamics compared to available commercial devices. Quantitative analysis of transient sensor signals identifies resonant frequency to allow for wireless monitoring of hemodynamics. Sensor functionality is displayed in mock blood vessels with pulsatile flow, which will enable continuous, wireless monitoring of hemodynamics throughout the vascular system.

Figure 1
The Exploration of a New Stable G-Triplex DNA and its Novel Function in Electrochemical Biosensing
Authors: Zhao Ling-Li , Cao Ting , Zhou Qian-Yu , Zhang Xiao-Hui , Zhou Ying-Lin , Yang Lijiang , Zhang Xin-Xiang
Published: May 2020

A G-triplex, a new kind of DNA structure, has been identified as an intermediate in the folding of G-quadruplexes. However, the studies on G-triplexes are still very limited, and the functions and applications of G-triplexes are further to be developed. In this paper, a new G-triplex sequence (5'-CTGGGAGGGAGGGA-3', G3), obtained by truncating four bases (GGGA) from the 3' end of an 18-base G-quadruplex sequence (G4), was found to significantly decrease the diffusion current of methylene blue (MB). In particular, we proved that a) MB stabilized the structure of G3 and increased the Tm of G3 considerably based on circular dichroism; and b) MB formed a 1:1 non-covalent complex with G3 based on electrospray ionization mass spectrometry. Moreover, molecular dynamics simulations established reliable speculation in the folding topology of G3 and interaction sites between G3 and MB. Based on the strong affinity of G3 with MB, we further developed a novel function of G3 as an electrochemical signal read-out and applied it in the fabrication of a sensitive homogeneous electrochemical aptasensor for cocaine. The features we observed in the G3/MB complex will serve as a new inspiring guideline for developing functional short G-rich ligands.
Exosomal Biomarkers-Based Biosensors for the Noninvasive Early Cancer Detection
Authors: Stobiecka Magdalena , Ratajczak Katarzyna , Jakiela Slawomir
Published: May 2020

Exosomes are extracellular vesicles released from cells, which contain in their membranes many ligands/receptors and membrane proteins, such as tetraspanins or major histocompatibility complex (MHC), that characterize the cell of origin. They can also carry various biomarkers depending on the type and state of the originating cell (proteins, mRNA, miRNA).

Recently, it has been found, that the serum-derived exosomes from patients with malignant gliomas contain survivin protein (Sur) on their surface [1]. Survivin is the smallest member of the inhibitor of apoptosis proteins (IAP) family. It is strongly expressed in embryos and malignant tumors but very weakly in the normal cells. Due to its active role in tumor growth and metastasis, Sur became a prime cancer biomarker [2].

It was also found by Li at al. [3] that the exosomal programmed cell death ligand 1 (Exo-PD-L1) level was correlated with non-small cell lung cancer (NSCLC) disease progression. The programmed cell-death ligand 1 (PD-L1) is an immuno-suppressive molecule commonly upregulated on the surface of tumor cells.

In this work, we have investigated the interactions of proteins expressed on the surface of exosomes with the anti-CD274 and anti-survivin antibodies immobilized on a gold piezoelectrode using the electrochemical quartz crystal nanobalance (EQCN) technique.

The biosensors developed in this work have enabled gaining further insides into the peculiar nature of the exosomes and their great potential for enhancing clinical diagnostics and therapy by identifying cancer biomarkers for early cancer detection without any invasive biopsies.

We would like to thank for financial support from the National Science Centre (NCN), Poland: Program OPUS Grant No. 2017/25/B/ST4/01362.

References:

[1] P.M. Galbo Jr., M.J. Ciesielski, S. Figel, O. Maguire, J. Qiu, L. Wiltsie, H. Minderman, R.A. Fenstermaker, 2017, Oncotarget, 8, 114722–114735.

[2] M. Stobiecka, K. Ratajczak, S. Jakiela, 2019, Biosens. Bioelectron., 137, 58–71.

[3] C. Li, C. Li, C. Zhi, W. Liang, X. Wang, X. Chen, T. Lv, Q. Shen,Y. Song, D. Lin, H. Liu, 2019, J. Transl. Med., 17, 355.