bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wireless Zero-Power Air Quality Electrochemical Sensor Card for Iot Applications
Authors: Stetter Joseph R , Peaslee David , Patel Vinay , Meulendyk Bennett J. 
Published: February 2020

A new business card size very low cost wireless electrochemical sensor device for use with smartphones and connection to the IoT has been developed. The gas sensor platform uses amperometric gas sensors, AGS, herein demonstrated for CO but easily expanded to many other important airborne contaminants. The NFC based communication could revolutionize low cost personal monitoring of environmental air quality. The technology is based on a 2-electrode electrochemical gas sensor, and can be adapted to a 3-electrode configuration as well. The platform is adaptable to other electrochemically active gases including but not limited to formaldehyde, H2, H2S, alcohol, NO2, CL2, O3 or SO2.
The application enables NFC equipped mobile phones and devices to communicate wirelessly with the sensor on demand. The phone app NFC provides all the power necessary to read the signal from the sensor and communicate the data to the smartphone. In this configuration the sensor needs no warm-up or stabilization time and has no need for a battery or power supply. By tailoring the electro-chemistry of the sensor, a zero external bias can be used and still maintain an effective response to the target analyte. For instance, testing has been performed using composite printed Pt electrodes and an aqueous electrolyte, packaged in a small cell (roughly 15mm x 15mm x 3.8mm). Properties such as stability and linearity have been studied and will yield a device with years of service in indoor, outdoor and workplace environments. A lower detection limit of about 200 ppb CO has been achieved making ambient air quality monitoring possible as well as CO alarms. We envision that this platform will be useful for many types of AGSs with differing electrode and electrolyte configurations for other gases.
The sensor module’s electronics consist of a few passive components, an NFC communications chip with analog or digital inputs, and a low power instrumentation amplifier. With modern flexible electronics, and engineered antennae, the device can be reduced in size for embedding into just about anything. Including a printed battery enables the device to log in real time, and allows for a 3 electrode sensor configuration in a postage stamp size.
Combining techniques such as screen printing of electrodes and electronics, reel to reel manufacturing, and conformal packaging, the cost to produce a complete gas detector can be less than a dollar each! This new capability allows widespread use in studies from environmental air quality to personal health and asset protection.

Figure 1
Sensitivity to Acetone By Epsilon-Phase Tungsten Trioxide Films Produced By Reactive Spray Deposition Technology
Authors: Ouimet Ryan J. , Ebaugh Thomas Allen , Bonville Leonard J. , Maric Radenka 
Published: February 2020

Studies have shown that when an individual with diabetes has low insulin levels, the body is unable to burn glucose and converts those molecules into ketones, predominantly acetone. That acetone then transfers into the blood stream before being exhaled by an individual’s breath. Rather than using current methods to monitor diabetes, such as a blood test conducted by a finger prick, some researchers have suggested measuring the acetone in exhaled breath as a noninvasive method to monitor diabetes [1].
This noninvasive diabetes monitoring method is made possible by using resistive sensors that utilize a thin-film deposited on interdigitated electrodes. While healthy individuals will exhale 300-900ppb acetone, individuals suffering from diabetes may exhale up to 1800ppb acetone [2]. Recent studies have shown an ability of these sensors to reach the sensitivity required to sense acetone in these diabetic cases. When the sensor is heated, the conductivity of the film increases and allows for the flow of electrons between digits of the sensor. When acetone is present, the acetone adsorbs onto the acetone-sensitive material causing a noticeable change in resistance. As the concentration of acetone increases, the amount of acetone adsorbed on the film increases, causing a change in resistance which allows researchers to correlate acetone concentration with a sensor resistance.
One acetone-sensitive material that researchers are studying is epsilon-phase tungsten trioxide. While other forms of tungsten trioxide, such as the gamma-phase, can also sense acetone, the specific structure and surface dipole of the epsilon-phase allows for a particular sensitivity to high dipole moment compounds such as acetone [2]. Unfortunately, this material is prohibitive to use, as the epsilon-phase tungsten trioxide is not the thermodynamically preferred structure at the operating temperature [1]. Some researchers have used dopants, such as silicon or chromium to stabilize the epsilon-phase. However, past research has shown that by using Reactive Spray Deposition Technology (RSDT), it is possible to directly deposit tungsten trioxide onto sensors and anneal the material to achieve the epsilon-phase [3]. Using these undoped epsilon-phase tungsten trioxide sensors, as seen in the scanning electron micrograph in Figure 1, we are able to achieve a sensitive and durable film which can be used to detect the concentrations of interest for diabetes monitoring. This work will examine the acetone sensitivity of the undoped epsilon-phase tungsten trioxide films developed using RSDT and compare them to other research.
References:
[1] L. Wang, A. Teleki, S.E. Pratsinis, P.I. Gouma. Chem. Mater. 20 (2008) 4794-4796.
[2] M. Righettoni, A. Tricoli, S.E. Pratsinis. Chem. Mater. 22 (2010) 3152-3157.
[3] R. Jain, Y. Wang, R. Maric. J. Nanotech. Smart Mater. 1 (2014) 1-7.

Figure 1
Electric Field Induced Melting: Effect of Non-Specifically Absorbed DNA
Authors: West Ryan M , Hetrick Wesley 
Published: February 2020

Electric-field induced melting of surface-bound DNA can be carried out using electrochemical detection without parallel spectroscopic monitoring. With proper selection of applied potentials, ionic strength, and DNA coverage, discrimination of single mismatches based on the kinetics of DNA melting can be carried out quickly and reproducibly. Electrodes are prepared by the sequential exposure to thiol-modified oligonucleotides, mercaptohexanol, and finally hybridization with complimentary target oligonucleotides. The target is subsequently melted off the electrode by applying a sufficiently negative potential. The mechanism of e-melting is up for debate but likely involves the electrostatic repulsion between DNA’s phosphate backbone and the electrode surface, destabilization of the base pair hydrogen bonding or pi stacking, or some combination of these effects and others.
The mercaptohexanol passivation layer plays an important role for electrochemical DNA sensing, particularly when the effects of electric field are crucial to the detection scheme as is the case in electrochemical melting. The mercaptohexanol layer, or some other alkyl thiol layer is almost universally used to remove non-specifically absorbed DNA from the surface and prevent further non-specific absorption. Physisorbed oligonucleotides that are not removed by the passivation layer are expected to have ill-defined interaction energies with the surface and will be expelled from the surface at potentials and rates different than the hybridized target oligonucleotides. Additionally, a uniform mercaptohexanol layer is necessary for a uniform electric field. In this work, we examine the extent to which non-specific absorption occurs even when the mercaptohexanol layer is present. We examine how non-specific absorption effects the melting behavior, including the melting potential, melting rate, and the reproducibility. Finally, we compare various methods for mitigating non-specific absorption. These methods include the use of surfactants during electrode modification, applications of potential pulse sequences to destabilize and remove physisorbed oligomers, and the use of elevated temperatures.
Easy Monitoring of L-Lactic Acid in Wine Samples Using Disposable Electrochemical Enzymatic Sensors
Authors: Fanjul Bolado Pablo , Pereira Silva Neves Marta Maria , González García María Begoña , Hernández Santos David 
Published: February 2020

In wine industry, the malolactic fermentation, employed to lower the overall tartness of wine, is usually monitored by following the diminishing level of L-malic acid and the increasing level of L-lactic acid. Consequently, the monitoring of L-lactic acid levels in the course of the fermentation plays an important role in wine quality testing [1-2]. L-lactic acid is typically determined using chromatography based techniques. However, although these methods are precise, require bulky instrumentation, trained personnel and are costly. Therefore, electrochemical biosensors appear as promising alternative for the development of simple, fast, low-cost and portable platforms for in situ L-lactic acid analysis.
In this work, an enzymatic electrochemical sensor for the determination of L- lactic acid in wine samples has been developed. These single-use, small sized, sensors allowed the specific determination of L-lactic acid between 0.02 mM and 0.3 mM. Different wine samples were assayed with the proposed sensors and the obtained results indicate that the developed methodology has an accurate performance.
In summary, these enzymatic electrochemical sensors revealed to be robust, highly stable, user-friendly and time-saving, demonstrating the possibility of being used for the decentralized monitoring of L-Lactic acid in wine samples as an analytical trustful tool.

References

[1] Analytical and Bioanalytical Chemistry (2014) 406:123–137.
[2] Biochemistry and Biophysics Reports (2016) 5:35–54.
Increasing the Efficiency of Amino Acids Detection By Electrochemical Methods on Amorphous Carbon Nitride a-CNx Electrodes
Authors: Faure Mathilde , Billon Florence , Le Potier Isabelle , Haghiri-Gosnet Anne-Marie , Tribollet Bernard , Deslouis Claude , Pailleret Alain , Gamby Jean 
Published: February 2020

The naphthalene-2,3-dicarboxyaldehyde (NDA) label is widely used for the derivatization of amino acids (AAs) to form N-2-substituted-1-cyanobenz-[f]-isoindole derivatives (CBI) which are both fluorescent and electroactive. [1],[2] Optimal conditions for labeling were previously obtained when [NDA]tot/[CN-] ratio =1 and [NDA]tot /[amino acid or peptide]=40 with a buffer pH of 10. [3],[4] The detection step was achieved by using a carbon reference material (glassy carbon electrode ) exhibiting an obvious oxidation peak for CBI-AA observed at 0.5V/SCE [1]. These experiments confirmed that NDA can by used as a derivative agent for non electroactive AA, allowing for simultaneous electrochemical and fluorescence detections. In this work, amorphous carbon nitride a-CN0.26 thin films were elaborated on transparent and conductive glass/indium-tin oxide (ITO) wafers to improve the electroanalytical detection of AAs. The results obtained on as-grown a-CN0.26 were compared to the glassy carbon (GC). It was shown that a soft anodic pre-treatment protocol on glass/ITO/a-CN0.26 electrode in KCl solution drastically improved the CBI-AA oxidation peak performances. The oxidation peak potential for all CBI derivatives varied in the same range that those on GC and pre-treated glass/ITO/a-CN0.26, while no discrimination could be obtained for as-grown glass/ITO/a-CN0.26. For almost all the tested CBI derivatives, the electrochemical properties determined by electrochemical impedance spectroscopy (R
ct, charge transfert resistance) and by differential pulse voltammetry (peak areas, full-widths at peak mid-height, peak current density and their SD values) were improved on pre-treated a-CN0.26 in comparison with GC.

[1] M. Faure, S. Korchane, I. Le Potier, A. Pallandre, C. Deslouis, A.-M. Haghiri-Gosnet, J. Gamby, Investigating of labeling and detection of transthyretin synthetic peptide derivatized with naphthalene-2,3-dicarboxaldehyde, Talanta, 116 (2013) 8-13.
[2] M. Faure, A. Pallandre, S. Chebil, I. Le Potier, M. Taverna, B. Tribollet, C. Deslouis, A.-M. Haghiri-Gosnet, J. Gamby, Improved electrochemical detection of a transthyretin synthetic peptide in the nanomolar range with a two-electrode system integrated in a glass/PDMS microchip, Lab Chip, 14 (2014) 2800-2805.
[3] S. Korchane, A. Pallandre, C. Przybylski, C. Poas, F. Gonnet, M. Taverna, R. Daniel, I. Le Potier, Derivatization strategies for CE-LIF analysis of biomarkers: Toward a clinical diagnostic of familial transthyretin amyloidosis, Electrophoresis, 35 (2014) 1050-1059.
[4] M. Faure, I. Le Potier, A. Pallandre, S. Chebil, A.-M. Haghiri-Gosnet, C. Deslouis, E. Maisonhaute, J. Gamby, Determination of the isomeric forms proportion of fluorogenic naphthalene-2,3-dicarboxaldehyde in a binary mixture of water:methanol using electrochemical methods, Talanta, 148 (2016) 494-501.
Simultaneous Electrochemical Determination of Purine and Pyrimidine Bases Using Cu Doped CeO2 Nanoparticles Modified Glassy Carbon Electrode
Authors: Lavanya Nehru , Sekar Chinnathambi , Neri Giovanni 
Published: February 2020

Deoxyribonucleic acid (DNA) is an important hereditary substance in humans and in almost all other living organisms. It plays a vital role in the storage of genetic information and instructs the biological synthesis of proteins and enzymes through the process of replication and transcription of heritage information Thus, the identification and quantification of either individual and/or group of purine and pyrimidine bases are important for diagnosis of certain diseases and genetic disorders. Though there exits quite a few methods for such sensing, there is a great demand for a cheap, sensitive and interference free electrode for simultaneous determination of all the four neuclobases due to their important role in medical diagnosis, crime detection and biocomputing.
In the present work, an efficient electrochemical sensor has been fabricated for simultaneous determination of purine bases adenine (AD), guanine (GU) and pyrimidines bases thymine (TY), cytosine (CY) using Cu doped CeO2 nanoparticles modified glassy carbon electrode (Cu-CeO2/GCE). Direct electrocatalytic activities of DNA bases have been studied in phosphate buffer solution (PBS, pH 7.0) without any enzyme using voltammetric techniques. 3 wt% Cu doped CeO2 modified GCE showed two well defined anodic peaks each corresponding to the oxidation of purine (AD, GU) and pyrimidine (TY, CY) bases with significant peak to peak potential separation of 312 mV (AD-GU) and 200 mV (TY-CY) which were large enough for the selective and simultaneous determination of these bases in their mixture. Under optimum conditions, calibration plots for the simultaneous detection of the purine and pyrimidine bases were linear in the concentration range of 0.1– 500 μM for AD, 1–650 μM for GU, 1-300 μM for TY and 1-250 for CY with detection limit values of 0.021, 0.031, 0.024 and 0.038 μM respectively. Additionally the developed sensor exhibited good repeatability, reproducibility, sufficient stability and good anti-interference ability and was successfully applied for simultaneous detection of AD, GU, TY and CY in denatured DNA sample with satisfactory results.

References

Y. Deng, Y.L. Xia, C.H. Xiao, Biosens. Bioelectron. 31 (2012) 469–474.

N. Lavanya, C. Sekar, R. Murugan, G. Ravi, Mater. Sci. Engg. C 65 (2016) 278–286.
Electrodeposition of Both Carbon Nanotube and Glucose Oxidase on Pt Eectrode Using a Dispersed Electrolytic Solution
Authors: Yasuzawa Mikito , Uchimaru Masahiro , Jhong Huan-Ping , Kurashina Masashi , Wang Chen-Hao , Fuchiwaki Yusuke , Harada Toshihiko 
Published: February 2020

Immobilization of the enzyme is one of the most critical processes for the fabrication of an enzyme sensor, since it will highly influence properties of the obtained sensor. Various procedure have been proposed for a the preparation of glucose sensor, such as covalent attachment, cross-linking, hydrogel entrapment, polymer film entrapment, and the combination of two or more methods. Among the various techniques, the electrodeposition method is interesting owing to its simple preparation, miniaturization, and precise localization of enzyme.
On the other hand, nanocarbons (NCs), such as carbon nanotubes (CNTs) and graphenes, are extremely attractive in biosensor application, since they can combine properties of the high surface area, high stability and good electrical conductivity. However, NCs is not soluble in aqueous solution, which is the least media to dissolve enzyme without reducing its activity. The use of surfactants is a candidate to preparer a disperse NCs in enzyme solution, while this may also reduce the enzyme activity. Therefore, processes of enzyme immobilization and NCs immobilization are commonly performed separately using different solutions.
In this study, stable dispersed solutions of glucose oxidase (GOx) and multi-walled CNT were developed using gellan gum, which is a polysaccharide manufactured by microbial fermentation used widely as a gelling agents. By using this CNT/GOx dispersed solution, both CNT and GOx were successfully immobilized on Pt-Ir electrode by a simple step of applying a constant potential of 1.3 V（vs. Ag/AgCl) to the electrode in this solution. The electropolymerization of o-phenylenediamine was followed in order to increase the stability of enzyme-immobilized electrode. The CNT/GOx immobilized electrode performed as a glucose sensor with a high sensor sensitivity. This indicate that the introduction of CNT in GOx-immobilized film increased the efficiency of electron transfer between the electrode and generated hydrogen peroxide. In addition, the reproducibility of electrode fabrication was satisfactorily improved by the use of gellan gum compared with that using Triton X-100 as a dispersing agent.
Suspended Graphene-Based Electrochemical Sensor for Ultra-Sensitive Detection of Electroactive Dopamine (neurotransmitter) Signals
Authors: Kumar Rakesh , Dang Caroline , Hadi Faisal , Dawood Omar , Sexton James , Missous Mohmad , Jackson Dean , Young R , Koehne Jessica E. , Boult Stephen , Dixon Neil , Migliorato Max 
Published: February 2020

Graphene – a single atom thick 2D material, has demonstrated extraordinary potential as ultrasensitive and specific biological and chemical sensors1,2. This is because every carbon atom in suspended graphene is a surface atom which can be covalently/non-covalently interfaced with a wide range of chemical/biological species3 for detection at the single molecule level. Additionally, the charge transport through graphene can be modified via liquid gating, which forms a sensitive electrochemical method of detecting signals from charged species bonded to the graphene surface. Recently, graphene has demonstrated selective detection of electroactive signals from dopamine-a catecholamine neurotransmitters, which are found in the mammalian central nervous system4. Pristine graphene’s superior electronic and electrochemical properties can be exploited as analytical electrochemical sensors for measuring exocytosis during communication between cells under in vitro conditions, thereby monitoring cognitive and behavioural functions of living organisms
We have developed a 3 mm X 3 mm graphene chip with an array of two terminal devices, connected in parallel, in which each individual device consists of a monolayer graphene suspended over multiple cavities and clamped by two metal contacts. Suspended graphene, as opposed to substrate-based graphene, significantly reduces the surface charge hindrances and allows for ultrasensitive detection of electroactive signals. The fabricated graphene chip has been successfully tested as a VOC and electrochemical sensor. Currently, testing is underway to use the device as an electrochemical dopamine sensor. We intend to discuss initial electrochemical dopamine sensing results as well as to explore possible collaborations with research groups for testing the graphene chip as an in-vitro neurotransmitter sensor.
References:
1. Yuan, Wenjing, and Gaoquan Shi. "Graphene-based gas sensors." Journal of Materials Chemistry A 1.35 (2013): 10078-10091.
2. Kuila, Tapas, et al. "Recent advances in graphene-based biosensors." Biosensors and Bioelectronics 26.12 (2011): 4637-4648.
3. Shao, Yuyan, et al. "Graphene based electrochemical sensors and biosensors: a review." Electroanalysis 22.10 (2010): 1027-1036.
4. Jackowska, Krystyna, and Pawel Krysinski. "New trends in the electrochemical sensing of dopamine." Analytical and bioanalytical chemistry 405.11 (2013): 3753-3771.
High Throughput Droplet Microfluidic Platform for Single-Cell Lipid Analysis of Human Breast Cancer Cell Lines
Authors: Fernandez Renny Edwin , Monshi Md Monirojjaman , Bhushan Pulak , Bhansali Shekhar 
Published: February 2020

Lipid metabolism has been viewed as an indicator of breast cancer. We report a single cell high throughput droplet microfluidic platform for lipid profiling of cells. Breast cancer cell lines (MCF7 and LLC1) are individually trapped in nanoliter droplets containing enzyme microbeads. Subsequently, the lipid contents of individual cells are hydrolyzed by the microbeads in the droplet followed by electrochemical detection using a microelectrode array. Our droplet-based microfluidic platform integrates cell lysis and localized hydrolysis within a micron sized aqueous drops (40 µm) in an inert carrier oil (Fig. 1). The quantity of the hydrolyzed products in each droplet correspond to the lipid profile of individual cells. The magnitude of electrochemical impedance variations are characterized and related to tumor progression. The cellular heterogeneity of an apparently homogenous cell population has been identified. The change in electrochemical signals is correlated to the amounts and types of lipids in breast cancer cell lines.
Preliminary studies reveal the potential of our droplet microfluidic platform in comparing the chemical composition between cell types and even between individual cells. Cell-to-cell variability, which is not reflected in the ensemble profiles, was preserved in the proposed method. The microfluidic platform is also being integrated with bioimpedance analysis for advanced bioimpedance profiling. We identified that this approach leads to (a) functional identification of lipid variation in cancer cell lines during various stages of growth, (b) Tumor progression related to lipogenesis and fatty acid synthesis. The platform is also being extended to pathogenesis and drug-discovery

Figure 1