bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Touch Sensor Using Ion Gel
Authors: Hara Yuta , Yoshida Kazunari , Ahmed Kumkum , Khosla Ajit , Kawakami Masaru , Furukawa Hidemitsu 
Published: February 2020

The polymer gel is composed of polymeric chains which are crosslinked in a three-dimensional (3D) network structure and liquid which is widely applied to tissue engineering, medical treatment, and solid state electrochemical devices. The gel contains a large amount of water inside the three-dimensional network structure. The human body is also mostly composed of water, hence, the percentage of water in human body is relatively high similar to hydrogel. However, water contained in the gel evaporates in the air atmosphere.
Among various kind of gel, ion gel possessing ionic liquid is beneficial for applications since ionic liquids are liquid salts at room temperature and have useful properties such as non-volatility, non-inflammability, electrochemical stability, thermal stability and high ionic conductivity. In this study, we investigated the piezoelectric properties of ion gels to apply them for touch and pressure sensors in soft-matter robotics.
In this study, the used ion gel was made utilizing thiol-ene reaction and was composed of thiol monomer. The thiol-ene reaction is hardly influenced by the surrounding environment, hence, we can easily make ion gel. In addition, it is possible to form any objects using a photopolymerization initiator and a 3D printer. The aim of this research is to develop a tactile sensor using ion gel having non-volatility, non-flammability, thermal stability, high conductivity and softness close to humans.
The sensor is composed of ion gel and silicone rubber. It was made by injecting an ion gel into silicone rubber. The changes of impedance is measured by the change of shape of the ion gel due to the pressure. The sensor was tested with a press tester and an LCR meter for pressure sensing. It shows 521 kPa in maximum pressure sensing.
Currently, we are working on three-dimensional modeling of the sensor by using an ion gel and an insulating gel instead of using a mold. The technique shown in this study is expected to be applied to soft robot and robot hand.
Wide Linear Range Detecting Non-Enzymatic Glucose Sensor Based on Cu-CuO Nanoparticles Decorated TiO2nanotubes
Authors: Zhou Zhiru , Zhou H. Susan 
Published: February 2020

We successfully fabricated Cu-CuO/TNT electrode by coating the Cu-CuO nanoparticles onto TiO2 nanotube arrays surface through electrochemical deposition method, which is easy to operate and fast procedure. After the electrochemical deposition, Cu-CuO nanoparticles with a diameter of ~200nm were well dispersed onto TNT surface, which then given a smooth interaction surface and a 3D nanostructure with high uniformity. The as prepared Cu-CuO/TNT electrode was then used for non-enzymatic in vitro detection of glucose in sodium hydroxide (NaOH) solution. The non-enzymatic glucose sensor exhibits great analytical performance with wide linear range between 0.2-90mM, high sensitivity of 234 μA mM-1cm-2and low limit of detection of 0.019. Other than that, it also shows great selectivity toward glucose in presence of other interference species such as ascorbic acid(AA), dopamine(DA), uric acid(UA), lactose, sucrose, and fructose.
The wide linear range between 0.2-90mM of the sensor is really potential to be used for clinical and biopharmaceutical application. For diabetic patient, blood glucose concentrations can increase up to 40mM after glucose intake. For biopharmaceutical industry, glucose concentration can increase up to 80mM in the cell culture bioreactor. Current sensing platform described in a large part of scientific publication have little if no chance for application as their linear range is often outside the physiological range. In light of this information, the proposed non-enzymatic glucose sensor can be used for continuous monitoring of glucose in most applications.

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Micro- and Nanoelectrodes: Fabrication, Characterization and Application. the Detection of Silver and ROS/Rns in Biological Buffer
Authors: Sidambaram Prabhakar , Colleran John 
Published: February 2020

The electrochemical determination of low concentrations of silver, and the short-lived highly reactive oxygen and nitrogen species (ROS/RNS), requires reliable, reproducible measurements with sensitive analytical methods. In this work, gold, platinum and platinum black micro and nanoelectrodes were fabricated. Characterisation revealed flat disk-shaped working areas of 20 - 25 µm (micro) and 1 - 10 nm (nano) in diameter, derived from steady-state limiting currents and validated using FE-SEM.[1] Reported studies on silver detection have been carried out under a myriad of conditions but, to date, electrochemical determination of silver in biological buffers and media has not been successful.[2] Ultra-low concentrations of silver (1 nM – 80 nM) were determined, by anodic stripping voltammetry (ASV) with Ag/AgBr as a reference electrode, using micro- and nanoelectrodes of platinum and gold in chloride-free phosphate buffer (PB, pH 7.4). Laser pulled electrodes exhibit highly reproducible stripping voltammetry data for the determination of silver and returned linear calibration curves. A low detection limit of 1.3 pM in this medium provides the ability to explore silver and silver-based bioinorganic drug uptake by tumour and microbial cells. [3]
This study also includes the fabrication of Pt/Pt-black nanoelectrodes for the detection of ROS/RNS in chloride-free PB (pH 7.4). These data should help with the identification and quantitation of cellular ROS/RNS release. In particular, monitoring oxidative stress, as a cellular response on exposure to bioinorganic drugs, should help to elucidate the interaction pathway of bioinorganic anti-cancer drugs. We envisage that electrochemical speciation studies will help to elucidate the mechanism of action and cellular uptake of bioinorganic silver-based anti-microbial and anti-cancer drugs in cell sustaining media for in vitro and, potentially, in vivo single cell analysis.
[1] Percival, S. J. et al., RSC Adv. 2014, 4 (21), 10491.
[2] Radulescu, M. C. et al., Sensors 2010, 10 (12), 11340.
[3] Prabhakar Sidambaram. et al., J. Electrochem. Soc. 2019, 166, 6, B532.
The Influences of Organic Matter Concentrations in Juices for Pathogen Detection Using Phage-Based Biosensors
Authors: Chen I-Hsuan , Zhang Zheye , Du Songtao , Liu Yuzhe , Huang Tung-Shi , Chin Bryan A. 
Published: February 2020

Fruit and vegetables are playing an important role of today’s healthy diet. Juices are the liquid extracts from fruit and vegetables, which contain lots of organic matters, such as vitamins, minerals and plant chemicals (phytonutrients). Commercial bottle juices usually contain different percentages of real juices in their juice products. Therefore, the amount of organic matter content in juices are different in various brands of juices.
The foodborne pathogen outbreaks through the consumption of fruit or vegetable juices continue to be reported (CDC, 2016). It indicates that pathogens like Salmonella can be packaged with juices even with current manufacture microbial-inactivation process. According to several studies, the acidity in tomatoes juice and the phyto-chemicals (like chlorophyll) from damage leaves in leafy greens samples can affect the sensitivity of pathogen detection in juices. For example, chlorophyll is one of the substances in leafy green juice that inhibits PCR reaction for pathogen detection. This made the pathogen detection in some juices a difficult task to achieve.
The phage magnetoelastic (ME) biosensors are wireless sensors, whose resonance oscillation and resonance frequency are actuated and detected through magnetic fields. These biosensors have been shown to be highly sensitive and specific in pathogen detection including Salmonella on various food surfaces or liquids (Li et al., 2010). Therefore, in this study, different concentrations of juices from tomatoes and spinach with artificially spiked Salmonella (at the concentration of 104 cfu/ml) was tested by ME biosensors. The influence of pathogen detection capability was then studied by comparing the bacterial capture rates on biosensors. In tomato juice, the results showed that the capture rate of Salmonella can be reached up to 90.68% by using 100 ME biosensors in a tube rocking experiment with 10% tomato juice content. In spinach juice, the capture rate of Salmonella showed similar results as 90.68% in the same 10% juice concentration. However, when the juice concentration of spinach went up to 15% and 20%, the bacterial capture rate slightly decreased. The Salmonella capture rate were shown as 89.82% and 89.065, respectively. The decreasing of capture rate was obvious by using 50 ME sensors for the 15% and 20% spinach juices.
In conclusion, by using 100 phage ME biosensors, the detection platform can detect as high as 89% Salmonella in high juice concentration (15 % and 20%) of both tomato and spinach juice samples. While in the moderate juice concentration zone (5-10%), the ME biosensors show very promising results of detecting 90% Salmonella in both juices.
Wireless, Soft, Low-Profile Bioelectronics for Quantitative Diagnostics of Cervical Dystonia
Authors: Kwon Young-Tae , Yeo Woon-Hong 
Published: February 2020

Cervical dystonia (CD) is one of the most chronic neurological syndromes, leading patients to repetitive movements and abnormal postures. CD patients suffer substantial decrease in function and quality of life including normal activities of daily living such as cooking, dressing, eating, and driving. The traditional methods for assessment of CD have involved clinical rating scales that is the Toronto Western Spasmodic Torticollis Rating-2 (TWSTRS-2) [1]. However, rating these scales based on visual observation is subject to change upon the level of training and expertise of the clinician, which significantly prevents rapid and accurate identification of CD.
Here, we introduce the first demonstration of a soft skin-like, wireless electronic system, referred to as “SKINTRONICS”, which can quantify 4 types of disorder (torticollis, laterocollis, retrocollis, and anterocollis) and the severity levels of symptoms. The ideas begin with the employment of a highly sensitive accelerometer for accurate recording of total head movements in a soft, ultrathin, conformal wearable platform. The soft-membrane construction allows the biopatch gently and seamlessly mounted on the forehead of a patient with negligible effects on natural head motions while supplying sufficient and reliable digital signals throughout the diagnostic process of CD. To validate the device accuracy, a direct comparison between SKINTRONICS-based assessment and TWSTRS-2 based manual assessment is provided from a clinical study with 5 patients and 5 healthy subjects. Collective results indicate the new class of technology platforms for wireless, diverse, accurate monitoring of abnormal head movements illuminates more effective and safe treatments to patients for improved CD healthcare.

Reference

[1] C. L. Comella et al., Mov. Disord. 2016, 31(4), 563-569.
Highly Accurate, Stable Solid-State Microelectrode for an Electrochemical Glucose Sensor
Authors: Lim Hyo-Ryoung , Hillman Nathan Patrick , Kim Yun-Soung , Yeo Woon-Hong 
Published: February 2020

Wearable glucose sensors offer the promise of determining necessary insulin doses by analyzing bodily fluids in a noninvasive and continuous manner. Beyond ionotropic and optical methods that are already commercially available, electrochemical sensors can offer a small form factor, low cost, and easy fabrication process, enabled by its two-electrode configuration. Recent works have demonstrated an enhancement of sensing capabilities in the working electrode regarding both enzymatic and non-enzymatic materials. However, a reference electrode that uses the well-known silver/silver chloride (Ag/AgCl), still requires a performance improvement, especially as a form of a low-profile, solid-state configuration. The design of a solid-state electrode has reliability issues, driven in part by the non-use of a liquid chloride-based solution where the existing sensors are stored. Therefore, it is urgently needed to develop a new sensor with higher sensitivity and durability, while covering a broader range of concentrations.
Here, this study reports a newly developed solid-state Ag/AgCl electrode that offers enhanced accuracy and long-term stability in a very small form factor. Ag-deposited Si wafer was annealed to address a delamination issue before anodic chlorination. Fast scan cyclic voltammetry was performed to make conformal AgCl film on the Ag, providing an intimate contact. The correlation between electrochemical variables and stability was analyzed by changing the voltage range and the number of cycles. The initial stage of nucleation, surface morphology and structure of the multilayer were also studied to validate the improved flexibility. The resultant electrode shows high stability in DI water, pH buffer, and saline solution after adopting Nafion as an uppermost membrane. Collectively, this work provides a long-term stable (> 1 week) solid-state reference electrode which can be used for developing a wearable electrochemical glucose sensor.

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Towards Closed Loop Control of Cell Production: Analysis of Volatile Organic Profiles in Stem Cells By Comprehensive Two-Dimensional Gas Chromatography with Time-of-Flight Mass Spectrometry
Authors: Heist Christopher A. , Dimandja Jean-Marie D. , Navaei Milad 
Published: February 2020

Personalized cell therapies have demonstrated clinical benefits and have shown great promise in solving monogenetic diseases. Despite these documented benefits, commercialization has been limited due to challenges including manufacturing, characterization, quality control, and stability. Previous work has demonstrated the potential of gas chromatography coupled with mass spectrometry to evaluate the volatile organic profiles of cell cultures. However, due to the complexity of the medium and the intensity of the identified peaks, the data has been limited. This work reports on the development of a method to investigate the volatile organic compound (VOC) profiles of stem cells using the increased resolution of comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC/TOF MS) for the purpose of stem cell characterization, growth status analysis, and identification of critical quality attributes.
Mesenchymal stem cells (MSCs), from a variety of sources, were cultured and analyzed throughout their growth process. Samples of spent cell culture media were collected during cell passaging and incubated prior to analyzing the headspace above the media. Solid phase microectraction (SPME) was used as to concentrate the VOCs present in the sample headspace. The use of SPME, in conjunction with GCxGC/TOF MS allowed for an expanded understanding of the MSC volatilome and the development of relevant VOC profiles. The effect of growth media, cell source, growth status, and confluency on the chemicals identified in the VOC profiles was studied. Non-targeted analysis revealed more than 100 compounds of potential interest identified through spectral deconvolution and the NIST library of electron impact spectra. The identities of the compounds of interest was validated through the use of analytical standards. Principal component analysis (PCA) was used to reduce dimensionally and visualize variance in the data. Hierarchical clustering analysis was employed to assess relatedness between samples based on their volatile organic profiles. The distinct variations between the volatilomes is able to distinguish different cell sources and growth statuses.
While this work is in its preliminary stage, it lays the foundation for closed loop control of cell manufacturing. The identification of critical quality attributes and their associated VOC profiles, using powerful laboratory equipment is the first step in closing the manufacturing loop. With the newfound knowledge, miniaturized in-line sensors can be developed to allow for complete control of the cell manufacturing process, assuring not only a high quality product, but an efficient manufacturing process as well.

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Development of Low Power Micro Preconcentrator (μPC) for Chemical Sensing Applications
Authors: Lotfi Ardalan , Heist Christopher A. , Navaei Milad 
Published: February 2020

In recent years, there is a growing need for environmental monitoring systems that can reliably trace contaminants that affect human health and environmental safety. These systems comprise of three main sub-systems: the detector(s), separation columns, and pre-concentrators. The pre-concentrator is the vital part of any systems. The pre-concentrator is used to purify a sample that increases the concentration of the targeted analytes in a range of detection limit of the detector. The ideal pre-concentrator has high adsorption capacity and desorption efficiency [1]. In this work, we have optimized the pre-concentrator’s geometry by maximizing the active surface to volume ratio while improving the desorption efficiency. These optimizations reduce the power consumption, pressure drop across the channel while shortening desorption time.
The fabrication process starts with transfer of mask pattern on to a silicon wafer using photolithography and etching the silicon using Deep Reactive Ion Etching (DRIE) for 360 µm. Next, a double sided polished silicon wafer is used to seal the pre-concentrator by gold eutectic fusion bonding [2]. The last step is to deposit the heater on the backside of the wafer using the lift-off process. The advantage, of DRIE over wet etch, is to have a high aspect ratio structure and low surface roughness level. The low surface roughness is essential for the uniform coating of the adsorbing material. The positive photoresist SPR 220 is used as the soft mask for DRIE process to reduce fabrication steps. The pre-concentrator has pillars with 50 µm in diameter and 25 µm in spacing. Other critical dimensions have been shown in Figure 1(a). The total surface to volume ratio of the pre-concentrator is 58,000 m-1 with the total volume of 13.8 µL. To optimize the geometry of the pre-concentrator, a COMSOL model was developed to calculate the pressure drop across the preconcentrator while evaluating the heater performance. The preconcentrator ramp rate is 47.5 °C/second and the average power consumption is, Figure 1(b). The pressure drop across the pre-concentrator is 1.2 kPa for the air flow of 40 sccm.

Voiculescu, I., M. Zaghloul, and N. Narasimhan, Microfabricated chemical preconcentrators for gas-phase microanalytical detection systems. TrAC Trends in Analytical Chemistry, 2008. 27(4): p. 327-343.

Navaei, M., et al., Micro-Fabrication of All Silicon 3 Meter GC Columns Using Gold Eutectic Fusion Bonding. ECS Journal of Solid State Science and Technology, 2015. 4(10): p. S3011-S3015.

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Polyaniline Based Ternary Hierarchical Microspheres for Supercapacitor Application
Authors: Jeyaranjan Aadithya , Sakthivel Tamil Selvan , Seal Sudipta 
Published: February 2020

With rapid advancements in renewable energy harvesters and flexible electronics, there is a dire need to develop energy storage devices (EEDs) that respond well to these applications. Supercapacitors are a type of EEDs with higher energy and power densities. This, combined with their ultra high cycle life makes them an attractive candidate to be used both as a standalone or coupled with other EEDs.
The active material in supercapacitors can be broadly classified into three types: carbonaceous, conductive polymer, and metal oxides. Each category of materials has its own advantages and drawbacks. It is reasonable to formulate a ternary composite such that the advantage of one material effectively suppresses the drawback of the other. Herein, a ternary hierarchical microsphere (TMS) composed of polyaniline nanofibers, CeO2 nanorods, and reduced graphene is obtained through a simple and highly scalable spray-drying technique.
The synthesized TMS was physiochemically characterized using XRD, FTIR, SEM, XPS, and gas adsorption surface analysis. Electrochemical analysis revealed that the optimized TMS possess high specific capacity (685 F g-1), good rate performance and excellent cycle life (~90% capacitance retention after 6000 cycles). An asymmetric device constructed using the TMS and rGO revealed a high specific energy density (46.3 W h kg-1) at a power density of 850 W kg-1 with a very stable cyclic performance. Thus, we demonstrate a simple yet effective strategy to produce high-performance supercapacitor material, which is highly scalable for industrial-scale production.
Stretchable and Thermally Stable Cellulose Film
Authors: Oh Jee Eun , Park Nae-Man , Choi Sukyung 
Published: February 2020

Glass has been widely used as a substrate for display, because of its high transparency and low thermal expansion coefficient. However, glass is not suitable for stretchable displays because it is easily broken and has no ductility. Instead of glass, synthetic polymers can be alternative. However, most synthetic polymers have low transparency and high thermal expansion coefficient. Therefore, as a substitute for glass or synthetic polymer, cellulose nano-fiber was used to make transparent, stretchable and thermally stable film.1
Cellulose is composed of β-(1,4) linked D-glucose unit. Glucose has three hydroxyl groups on surfaces and it can form hydrogen bonds with Nitrogen, Oxygen and Fluorine. Cellulose composed of glucose has many hydroxyl groups. Due to these hydroxyl groups, they are dense with strong hydrogen bonds between the fibers. The cellulose is formed by bundles of many nano-fibers. And it can be used to make a flexible film like paper. However, there is no elasticity because of the intense hydrogen bonding between the molecules.2
In order to impart elasticity to the cellulose, it is necessary to loosen the molecular structure and a network structure. Loosening the molecular structure is possible by modifying the hydroxyl group to another functional group so that the cellulose does not allow hydrogen bonding, or by using a solvent that interrupts and breaks hydrogen bonds between molecules. It is not enough to break hydrogen bonds to give elasticity, so that cross-linking was used to form a network structure.
Prior to cross-linking, cellulose fiber was treated by homogenizer to increase the surface area and reaction efficiency of the cellulose. In this process, cellulose are nano fibrillized. Then, polymeric aldehyde was added as a cross-linking agent to the cellulose nano fiber.
In this work, the properties of the stretchable cellulose will be presented. To investigate thermal stability, DSC and TGA analyzes were performed. Tg was measured by DSC analysis and thermal decomposition temperature of cellulose film was measured by TGA anaylsis. Transparency was measured by the transmittance at various wavelengths. To determine the strength and elongation, tensile strength and strain were also measured.
REFERENCES
(1) Nogi, M; Iwamoto, S; Nakagaito, A; Yano, H. Optically Transparent Nanofiber Paper. 2009, Adv. Mater. 21, 1595–1598
(2) Striegel, A. Theory and applications of DMAc/LiCl in the analysis of polysaccharides. 1997, Carbohydrate Polymers 34, 267-214