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electrochemical sensor

Walter A Braun, Bruna C Horn, Lucélia Hoehne, Simone Stülp, Marcelo B DA Rosa, Maurício Hilgemann
A new modified electrode for indirect sensing of OH· and radical scavengers was described. The electrochemical polymerization of methylene blue in aqueous solutions and the properties of the resulting films on a glassy carbon electrode were carried out using cyclic voltammetry. A surface coverage of 1.11 × 109mol cm2 was obtained, revealing a complete surface coverage of the polymeric film on the electrode surface. OH· was able to destroy the poly(methylene blue) film by exposure to a Fenton solution. The loss of the electrochemical signal of the residual polymeric film attached to the electrode surface was related to the extent of its dissolution...
August 14, 2017: Anais da Academia Brasileira de Ciências
Bin Fan, Yan Zhu, Robert Rechenberg, Cory A Rusinek, Michael F Becker, Wen Li
Boron-doped diamond (BDD) has superior electrochemical properties for bioelectronic systems. However, due to its high synthesis temperature, traditional microfabrication methods have limits to integrating BDD with emerging classes of flexible, polymer-based bioelectronic systems. This paper introduces a novel fabrication solution to this challenge, which features (i) a wafer-scale substrate transfer process with all diamond structures transferred onto a flexible Parylene-C substrate and (ii) Parylene anchors introduced to strengthen the bonding between BDD and Parylene substrates, as demonstrated by a peeling test...
August 16, 2017: Lab on a Chip
Dongmei Wang, Xiaoqing Xiao, Shen Xu, Yong Liu, Yongxin Li
In this work, single Au nanowire electrodes (AuNWEs) were fabricated by laser-assisted pulling/hydrofluoric acid (HF) etching process, which then were characterized by transmission electron microscopy (TEM), electrochemical method and finite-element simulation. The as-prepared single AuNWEs were used to construct electrochemical aptamer-based nanosensors (E-AB nanosensors) based on the formation of Au-S bond that duplex DNA tagged with methylene blue (MB) was modified on the surface of electrode. In the presence of adenosine triphosphate (ATP), the MB-labeled aptamer dissociated from the duplex DNA due to the strong specific affinity between aptamer and target, which lead to the reduction of MB electrochemical signals...
August 9, 2017: Biosensors & Bioelectronics
Can Wu, Yuhang Zhang, Duo Dong, Haiming Xie, Jinghong Li
To promote the practical application of electrochemical energy storage and conversion systems, nonprecious electrocatalysts of low cost and with highly efficient performance in oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are highly desired. In this work, a cubic sodium chloride (NaCl) crystal-templated strategy is proposed for coupling Co9S8 nanoparticles to nitrogen- and sulfur-doped carbon nanosheets (Co9S8/N,S-CNS) by facile pyrolysis. The nitrogen and sulfur dual-doped carbon nanosheets can effectively prevent the aggregation of Co9S8 nanoparticles and greatly improve the conductivity of the hybrid structure...
August 15, 2017: Nanoscale
Liqi Dong, Youshan Zhang, Xuemin Duan, Xiaofei Zhu, Hui Sun, Jingkun Xu
The development of electrochemical methods for enantioselective recognition is a focus of research in pharmaceuticals and biotechnology. In this study, a pair of water-soluble chiral 3,4-ethylenedioxythiophene (EDOT) derivatives-(R)-2'-hydroxymethyl-3,4-ethylenedioxythiophene ((R)-EDTM) and (S)-2'-hydroxymethyl-3,4-ethylenedioxythiophene ((S)-EDTM)-were synthesized and electrodeposited on the surface of a glassy carbon electrode (GCE) via current-time (I-t) polymerization in an aqueous LiClO4 electrolyte. These chiral PEDOT polymers were used to fabricate chiral sensors and to investigate the enantioselective recognition of D-/L-3,4-dihydroxyphenylalanine, D-/L-tryptophan and (R)-/(S)-propranolol enantiomers, respectively...
August 15, 2017: Analytical Chemistry
Jonathan S McQuillan, Andrew K Morris, Martin Arundell, Robin Pascal, Matthew C Mowlem
An electrochemical anti-fouling method, based upon the generation of chlorine from seawater, was applied to a proprietary design of Lab on a Chip conductivity, temperature and dissolved oxygen sensor. The method was evaluated using PCR after a six-week field trial in which it significantly reduced the burden of bacterial biofouling.
August 10, 2017: Journal of Microbiological Methods
Alain Walcarius
The past decade has seen an increasing number of extensive studies devoted to the exploitation of ordered mesoporous carbon (OMC) materials in electrochemistry, notably in the fields of energy and sensing. The present review summarizes the recent achievements made in field of electroanalysis using electrodes modified with such nanomaterials. On the basis of comprehensive tables, the interest in OMC for designing electrochemical sensors is illustrated through the various applications developed to date. They include voltammetric detection after preconcentration, electrocatalysis (intrinsically due to OMC or based on suitable catalysts deposited onto OMC), electrochemical biosensors, as well as electrochemiluminescence and potentiometric sensors...
August 11, 2017: Sensors
Yao Wu, Rebecca Y Lai
We report the first electrochemical cisplatin sensor fabricated with a thiolated and methylene blue (MB)-modified oligo-adenine(A)-guanine(G) DNA probe. Depending on the probe coverage, the sensor can behave as a "signal-off" or "signal-on" sensor. For the high-coverage sensor, formation of intrastrand Pt(II)-AG adducts rigidifies the oligo-AG probe, resulting in a concentration-dependent decrease in the MB signal. For the low-coverage sensor, the increase in probe-to-probe spacing enables binding of cisplatin via the intrastrand GNG motif (N = A), generating a bend in the probe which results in an increase in the MB current...
August 11, 2017: Analytical Chemistry
Sixing Li, Fen Ma, Hunter Bachman, Craig E Cameron, Xiangqun Zeng, Tony Jun Huang
Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate E. coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells (RBCs) shows a purity of more than 96%...
January 1, 2017: Journal of Micromechanics and Microengineering: Structures, Devices, and Systems
Kevin Klunder, Zach Nilsson, Justin Sambur, Charles S Henry
Since their invention in the 1950's, composite carbon electrodes have been employed in a wide variety of applications, ranging from batteries and fuel cells to chemical sensors because they are easy to make and pattern at millimeter scales. Despite their widespread use, traditional carbon composite electrodes have substandard electrochemistry relative to metallic and glassy carbon electrodes. As a result, there is a critical need for new composite carbon electrodes that are highly electrochemically active, have universal and easy fabrication into complex geometries, are highly conductive, and are low cost...
August 10, 2017: Journal of the American Chemical Society
Gangbing Zhu, Heng Sun, Junjuan Qian, Xiangyang Wu, Yinhui Yi
The simultaneous and sensitive electrochemical detection of dihydroxybenzene isomers (hydroquinone, HQ; catechol, CC; resorcinol, RS) is of great significance because such isomers can be awfully harmful to the environment and human health. In this paper, by preparing poly(L-arginine) modified glassy carbon electrode (P-L-Arg/GCE) with a simple method, a highly sensitive electrochemical sensor for simultaneously detecting HQ, CC and RS was constructed successfully due to the large surface area, good electronic properties and catalytic ability of P-L-Arg/GCE and the electrostatic action between P-L-Arg (positive) and targets (negative)...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Ryo Matsuoka, Chihiro Kobayashi, Atsushi Nakagawa, Shigeo Aoyagi, Tatsuo Aikawa, Takeshi Kondo, Shigenobu Kasai, Makoto Yuasa
We have developed an electrochemical reactive oxygen/nitrogen species sensor that can detect superoxide anion radicals (O2(-•)) and nitric oxide (NO). The reactive oxygen/nitrogen species sensor was fabricated by surface modification of an electrode with polymerized iron tetrakis(3-thienyl)porphyrin (FeT3ThP), and it can detect either O2(-•) or NO by switching the applied potential. Furthermore, we fabricated a sensor with improved selectivity by coating a Nafion(®) film onto the poly(FeT3ThP)-modified electrode...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
GeonHui Lee, JuKyung Lee, JeongHoon Kim, Hak Soo Choi, Jonghan Kim, SangHoon Lee, HeaYeon Lee
Miniaturized microfluidic biosensors have recently been advanced for portable point-of-care diagnostics by integrating lab-on-a-chip technology and electrochemical analysis. However, the design of a small, integrated, and reliable biosensor for multiple and simultaneous electrochemical analyses in a single device remains a challenge. Here, we present a simultaneous microfluidic electrochemical biosensing system to detect multiple biomarkers of pulmonary hypertension diseases in a single device. The miniaturized biosensor, which is composed of five chambers, is precisely and individually controlled using in-house-built pneumatic microvalves to manipulate the flow pathway...
August 8, 2017: Scientific Reports
Di Kang, Sheng Sun, Martin Kurnik, Demosthenes P Morales, Frederick Willis Dahlquist, Kevin W Plaxco
Here we demonstrate a new class of reagentless, single-step sensors for the detection of proteins and peptides that is the electro-chemical analog of fluorescence polarization (fluorescence anisotropy), a versatile optical approach widely employed to this same end. Our electrochemical sensors consist of a redox-reporter-modified protein (the "receptor") site-specifically anchored to an electrode via a short, flexible polypeptide linker. Interaction of the receptor with its binding partner alters the efficiency with which the reporter approaches the electrode surface, thus causing a change in redox current upon voltammetric interrogation...
August 8, 2017: Journal of the American Chemical Society
Jayoung Kim, Itthipon Jeerapan, Bianca Ciui, Martin C Hartel, Aida Martin, Joseph Wang
This study demonstrates the first example of completely food-based edible electrochemical sensors. The new edible composite electrodes consist of food materials and supplements serving as the edible conductor, corn, and olive oils as edible binders, vegetables as biocatalysts, and food-based packing sleeves. These edible composite electrodes are systematically characterized for their attractive electrochemical properties, such as potential window, capacitance, redox activity using various electrochemical techniques...
August 7, 2017: Advanced Healthcare Materials
Yajun Pang, Guangqing Xu, Qiang Feng, Jiaqin Liu, Jun Lv, Yong Zhang, Yucheng Wu
One-dimensional anodic TiO2 nanotube arrays hold great potential as photoelectrochemical sensor for the determination of chemical oxygen demand (COD). In this work, we report a warm synthesis of modified TiO2 nanotube arrays with enhanced photoelectrochemical determination performance. Herein, a bismuth-based semiconductor (-Bi2Mo3O12) was introduced to TiO2 nanotube arrays by sequential chemical bath deposition at room temperature. The structures, elemental compositions and morphologies of the products were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy, respectively...
August 7, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Sevinc Kurbanoglu, Sibel A Ozkan
Nanotechnology has become very popular in the sensor fields in recent times. It is thought that the utilization of such technologies, as well as the use of nanosized materials, could well have beneficial effects for the performance of sensors. Nano-sized materials have been shown to have a number of novel and interesting physical and chemical properties. Low-dimensional nanometer-sized materials and systems have defined a new research area in condensed-matter physics within past decades. Apart from the aforesaid categories of materials, there exist various materials of different types for fabricating nanosensors...
June 28, 2017: Journal of Pharmaceutical and Biomedical Analysis
Reginald M Penner
Hydrogen gas (H2) is odorless and flammable at concentrations above 4% (v/v) in air. Sensors capable of detecting it rapidly at lower concentrations are needed to "sniff" for leaked H2 wherever it is used. Electrical H2 sensors are attractive because of their simplicity and low cost: Such sensors consist of a metal (usually palladium, Pd) resistor. Exposure to H2 causes a resistance increase, as Pd metal is converted into more resistive palladium hydride (PdHx). Sensors based upon Pd alloy films, developed in the early 1990s, were both too slow and too insensitive to meet the requirements of H2 safety sensing...
August 4, 2017: Accounts of Chemical Research
Hua Lin, Jun Yi
Glycated hemoglobin (HbA1c) is formed via non-enzymatic glycosylation reactions at the α-amino group of βVal1 residues in the tetrameric Hb, and it can reflect the ambient glycemic level over the past two to three months. A variety of HbA1c detection methods, including chromatography, immunoassay, enzymatic measurement, electrochemical sensor and capillary electrophoresis have been developed and used in research laboratories and in clinics as well. In this review, we summarize the current status of HbA1c biosensors based on the recognition of the sugar moiety on the protein and also their applications in the whole blood sample measurements...
August 4, 2017: Sensors
Dhiman Bhattacharyya, Pankaj Kumar, Swomitra K Mohanty, York R Smith, Mano Misra
Screening of colorectal cancer is crucial for early stage diagnosis and treatment. Detection of volatile organic compounds (VOCs) of the metabolome present in exhaled breath is a promising approach to screen colorectal cancer (CRC). Various forms of volatile organic compounds (VOCs) that show the definitive signature for the different diseases including cancers are present in exhale breathe. Among all the reported CRC VOCs, cyclohexane, methylcyclohexane, 1,3-dimethyl- benzene and decanal are identified as the prominent ones that can be used as the signature for CRC screening...
August 4, 2017: Sensors
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