WorldWideScience

Sample records for electrochemical sensing applications

  1. Fabrication strategies, sensing modes and analytical applications of ratiometric electrochemical biosensors.

    Science.gov (United States)

    Jin, Hui; Gui, Rijun; Yu, Jianbo; Lv, Wei; Wang, Zonghua

    2017-05-15

    Previously developed electrochemical biosensors with single-electric signal output are probably affected by intrinsic and extrinsic factors. In contrast, the ratiometric electrochemical biosensors (RECBSs) with dual-electric signal outputs have an intrinsic built-in correction to the effects from system or background electric signals, and therefore exhibit a significant potential to improve the accuracy and sensitivity in electrochemical sensing applications. In this review, we systematically summarize the fabrication strategies, sensing modes and analytical applications of RECBSs. First, the different fabrication strategies of RECBSs were introduced, referring to the analytes-induced single- and dual-dependent electrochemical signal strategies for RECBSs. Second, the different sensing modes of RECBSs were illustrated, such as differential pulse voltammetry, square wave voltammetry, cyclic voltammetry, alternating current voltammetry, electrochemiluminescence, and so forth. Third, the analytical applications of RECBSs were discussed based on the types of target analytes. Finally, the forthcoming development and future prospects in the research field of RECBSs were also highlighted. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Advances in electrospun carbon fiber-based electrochemical sensing platforms for bioanalytical applications.

    Science.gov (United States)

    Mao, Xianwen; Tian, Wenda; Hatton, T Alan; Rutledge, Gregory C

    2016-02-01

    Electrochemical sensing is an efficient and inexpensive method for detection of a range of chemicals of biological, clinical, and environmental interest. Carbon materials-based electrodes are commonly employed for the development of electrochemical sensors because of their low cost, biocompatibility, and facile electron transfer kinetics. Electrospun carbon fibers (ECFs), prepared by electrospinning of a polymeric precursor and subsequent thermal treatment, have emerged as promising carbon systems for biosensing applications since the electrochemical properties of these carbon fibers can be easily modified by processing conditions and post-treatment. This review addresses recent progress in the use of ECFs for sensor fabrication and analyte detection. We focus on the modification strategies of ECFs and identification of the key components that impart the bioelectroanalytical activities, and point out the future challenges that must be addressed in order to advance the fundamental understanding of the ECF electrochemistry and to realize the practical applications of ECF-based sensing devices.

  3. Application of ionic liquids in electrochemical sensing systems.

    Science.gov (United States)

    Shiddiky, Muhammad J A; Torriero, Angel A J

    2011-01-15

    Since 1992, when the room temperature ionic liquids (ILs) based on the 1-alkyl-3-methylimidazolium cation were reported to provide an attractive combination of an electrochemical solvent and electrolyte, ILs have been widely used in electrodeposition, electrosynthesis, electrocatalysis, electrochemical capacitor, and lithium batteries. However, it has only been in the last few years that electrochemical biosensors based on carbon ionic liquid electrodes (CILEs) and IL-modified macrodisk electrodes have been reported. However, there are still a lot of challenges in achieving IL-based sensitive, selective, and reproducible biosensors for high speed analysis of biological and environmental compounds of interest. This review discusses the principles of operation of electrochemical biosensors based on CILEs and IL/composite-modified macrodisk electrodes. Subsequently, recent developments and major strategies for enhancing sensing performance are discussed. Key challenges and opportunities of IL-based biosensors to further development and use are considered. Emphasis is given to direct electron-transfer reaction and electrocatalysis of hemeproteins and enzyme-modified composite electrodes. Copyright © 2010 Elsevier B.V. All rights reserved.

  4. Recent advances in the use of ionic liquids for electrochemical sensing.

    Science.gov (United States)

    Silvester, Debbie S

    2011-12-07

    Ionic Liquids are salts that are liquid at (or just above) room temperature. They possess several advantageous properties (e.g. high intrinsic conductivity, wide electrochemical windows, low volatility, high thermal stability and good solvating ability), which make them ideal as non-volatile electrolytes in electrochemical sensors. This mini-review article describes the recent uses of ionic liquids in electrochemical sensing applications (covering the last 3 years) in the context of voltammetric sensing at solid/liquid, liquid/liquid interfaces and carbon paste electrodes, as well as their use in gas sensing, ion-selective electrodes, and for detecting biological molecules, explosives and chemical warfare agents. A comment on the future direction and challenges in this field is also presented.

  5. Ordered mesoporous carbon for electrochemical sensing: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ndamanisha, Jean Chrysostome [Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China); Universite du Burundi, Institut de pedagogie appliquee, B.P. 5223, Bujumbura (Burundi); Guo Liping, E-mail: guolp078@nenu.edu.cn [Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China)

    2012-10-17

    Highlights: Black-Right-Pointing-Pointer The preparation and functionalization of ordered mesoporous carbon. Black-Right-Pointing-Pointer Their applications as electrochemical sensors with high electrocatalytic activity. Black-Right-Pointing-Pointer A promising electrode material based on its interesting properties. - Abstract: With its well-ordered pore structure, high specific surface area and tunable pore diameters in the mesopore range, ordered mesoporous carbon (OMC) is suitable for applications in catalysis and sensing. We report recent applications of OMC in electrochemical sensors and biosensors. After a brief description of the electrochemical properties, the functionalization of the OMC for improvement of the electrocatalytic properties is then presented. We show how the ordered mesostructure of OMC is very important in those applications. The high density of edge plane-like defective sites (EDSs), oxygen-containing groups and a large surface area on OMC may provide many favorable sites for electron transfer to compounds, which makes OMC a potential novel material for an investigation of the electrochemical behavior of substances. Moreover, the structural capabilities of OMC at the scale of a few nanometers agree with immobilization of other electrocataytic substances. Interesting properties of this material may open up a new approach to study the electrochemical determination of other biomolecules.

  6. One pot synthesis of dandelion-like polyaniline coated gold nanoparticles composites for electrochemical sensing applications.

    Science.gov (United States)

    Lu, Zhiwei; Dai, Wanlin; Liu, Baichen; Mo, Guangquan; Zhang, Junjun; Ye, Jiaping; Ye, Jianshan

    2018-04-18

    In this work, we report a facile and green strategy for one pot and in-situ synthesis of a dandelion-like conductive polyaniline coated gold nanoparticle nanocomposites (Au@PANI). The Au@PANI was characterized by SEM, TEM, XRD, TGA, FTIR, UV-vis and conductivity measurement, respectively. Newly-designed Au@PANI materials possessed a significantly high conductivity and strong adsorption capability. Thus, the Au@PANI modified glassy carbon electrode (GCE) was utilized for construct a novel electrochemical sensor for the simultaneous assay of Pb 2+ and Cu 2+ using square wave anodic stripping voltammetry (SWASV). Under the optimized conditions, an excellent electrochemical response in the simultaneous of Pb 2+ and Cu 2+ with detection limit of 0.003 and 0.008 μM (S/N = 3), respectively. Moreover, the prepared sensors realized an excellent reproducibility, repeatability and long term stability, as well as reliable practical assays in real water samples. Besides, the possible formation mechanism and sensing mechanism of Au@PANI nanocomposites have been discussed in detail. We believe this study provides a novel method of fabrication of noble metal nanoparticles decorated conducting polymer materials for the electrochemical sensing applications. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Layered Metal Nanoparticle Structures on Electrodes for Sensing, Switchable Controlled Uptake/Release, and Photo-electrochemical Applications.

    Science.gov (United States)

    Tel-Vered, Ran; Kahn, Jason S; Willner, Itamar

    2016-01-06

    Layered metal nanoparticle (NP) assemblies provide highly porous and conductive composites of unique electrical and optical (plasmonic) properties. Two methods to construct layered metal NP matrices are described, and these include the layer-by-layer deposition of NPs, or the electropolymerization of monolayer-functionalized NPs, specifically thioaniline-modified metal NPs. The layered NP composites are used as sensing matrices through the use of electrochemistry or surface plasmon resonance (SPR) as transduction signals. The crosslinking of the metal NP composites with molecular receptors, or the imprinting of molecular recognition sites into the electropolymerized NP matrices lead to selective and chiroselective sensing interfaces. Furthermore, the electrosynthesis of redox-active, imprinted, bis-aniline bridged Au NP composites yields electrochemically triggered "sponges" for the switchable uptake and release of electron-acceptor substrates, and results in conductive surfaces of electrochemically controlled wettability. Also, photosensitizer-relay-crosslinked Au NP composites, or electrochemically polymerized layered semiconductor quantum dot/metal NP matrices on electrodes, are demonstrated as functional nanostructures for photoelectrochemical applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Electrochemical structure-switching sensing using nanoplasmonic devices

    Energy Technology Data Exchange (ETDEWEB)

    Patskovsky, Sergiy; Dallaire, Anne-Marie; Blanchard-Dionne, Andre-Pierre; Meunier, Michel [Department of Engineering Physics, Laser Processing and Plasmonics Laboratory, Polytechnique, Montreal, Station Centre-ville, QC (Canada); Vallee-Belisle, Alexis [Laboratory of Biosensors and Nanomachines, Departement de Chimie, Universite de Montreal, QC (Canada)

    2015-12-15

    In this article, the implementation of electrochemical plasmonic nanostructures functionalized with DNA-based structure-switching sensors is presented. eNanoSPR devices with open and microfluidic measurement cells are developed on the base of nanohole arrays in 100 nm gold film and applied for combined microscopic and electrochemical surface plasmon (eSPR) visualization. eSPR voltammograms and spectroscopy are performed using planar three electrode schematic with plasmonic nanostructure operated as working electrode. Limit of detection of eNanoSPR devices for oligonucleotide hybridization is estimated in the low nanomolar and applications for structure-switching electro-plasmonic sensing in complex liquids are discussed. (copyright 2015 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. One-step and low-temperature synthesis of iodine-doped graphene and its multifunctional applications for hydrogen evolution reaction and electrochemical sensing

    International Nuclear Information System (INIS)

    Chu, Ke; Wang, Fan; Zhao, Xiao-lin; Wei, Xiao-ping; Wang, Xin-wei; Tian, Ye

    2017-01-01

    Iodine (I) has emerged as a powerful heteroatom dopant for efficiently tailoring the electrocatalytic properties of graphene. However, the preparation methods of I-doped graphene (I-G) and its electrocatalysis applications remain largely unexplored. Herein, a one-step and low-temperature hydrothermal approach was developed for the successful synthesis of I-G with a high I-doping level (0.52 at.%). The resulting I-G was then applied as a metal-free catalyst for hydrogen evolution reaction (HER) and electrochemical sensing. It was shown that the I-G exhibited a dramatically enhanced HER activity compared to undoped graphene, attributed to the critical role of I-doping in offering large exposed active sites and high electron transfer capability. Furthermore, I-G also displayed attractive sensing performances for highly sensitive and selective detection of dopamine. These findings demonstrate that the hydrothermally synthesized I-G can be a promising electrocatalyst for multifunctional applications in water-splitting and electrochemical sensing.

  10. A Paper-Based Electrochromic Array for Visualized Electrochemical Sensing

    OpenAIRE

    Fengling Zhang; Tianyi Cai; Liang Ma; Liyuan Zhan; Hong Liu

    2017-01-01

    We report a battery-powered, paper-based electrochromic array for visualized electrochemical sensing. The paper-based sensing system consists of six parallel electrochemical cells, which are powered by an aluminum-air battery. Each single electrochemical cell uses a Prussian Blue spot electrodeposited on an indium-doped tin oxide thin film as the electrochromic indicator. Each electrochemical cell is preloaded with increasing amounts of analyte. The sample activates the battery for the sensin...

  11. A Paper-Based Electrochromic Array for Visualized Electrochemical Sensing.

    Science.gov (United States)

    Zhang, Fengling; Cai, Tianyi; Ma, Liang; Zhan, Liyuan; Liu, Hong

    2017-01-31

    We report a battery-powered, paper-based electrochromic array for visualized electrochemical sensing. The paper-based sensing system consists of six parallel electrochemical cells, which are powered by an aluminum-air battery. Each single electrochemical cell uses a Prussian Blue spot electrodeposited on an indium-doped tin oxide thin film as the electrochromic indicator. Each electrochemical cell is preloaded with increasing amounts of analyte. The sample activates the battery for the sensing. Both the preloaded analyte and the analyte in the sample initiate the color change of Prussian Blue to Prussian White. With a reaction time of 60 s, the number of electrochemical cells with complete color changes is correlated to the concentration of analyte in the sample. As a proof-of-concept analyte, lactic acid was detected semi-quantitatively using the naked eye.

  12. A Paper-Based Electrochromic Array for Visualized Electrochemical Sensing

    Directory of Open Access Journals (Sweden)

    Fengling Zhang

    2017-01-01

    Full Text Available We report a battery-powered, paper-based electrochromic array for visualized electrochemical sensing. The paper-based sensing system consists of six parallel electrochemical cells, which are powered by an aluminum-air battery. Each single electrochemical cell uses a Prussian Blue spot electrodeposited on an indium-doped tin oxide thin film as the electrochromic indicator. Each electrochemical cell is preloaded with increasing amounts of analyte. The sample activates the battery for the sensing. Both the preloaded analyte and the analyte in the sample initiate the color change of Prussian Blue to Prussian White. With a reaction time of 60 s, the number of electrochemical cells with complete color changes is correlated to the concentration of analyte in the sample. As a proof-of-concept analyte, lactic acid was detected semi-quantitatively using the naked eye.

  13. Nanomaterials application in electrochemical detection of heavy metals

    International Nuclear Information System (INIS)

    Aragay, Gemma; Merkoçi, Arben

    2012-01-01

    Highlights: ► We review the recent trends in the application of nanomaterials for electrochemical detection of heavy metals. ► Different types of nanomaterials including metal nanoparticles, different carbon nanomaterials or nanochannels have been applied on the electrochemical analysis of heavy metals in various sensing formats/configurations. ► The great properties of nanomaterials allow the new devices to show advantages in terms of sensing performance (i.e. increase the sensitivity, decrease the detection limits and improve the stability). ► Between the various electrochemical techniques, voltammetric and potentiometric based ones are particularly taking interesting advantages by the incorporation of new nanomaterials due to the improved electrocatalytic properties beside the increase of the sensor's transducing area. - Abstract: Recent trends in the application of nanomaterials for electrochemical detection of heavy metals are shown. Various nanomaterials such as nanoparticles, nanowires, nanotubes, nanochannels, graphene, etc. have been explored either as modifiers of electrodes or as new electrode materials with interest to be applied in electrochemical stripping analysis, ion-selective detection, field-effect transistors or other indirect heavy metals (bio)detection alternatives. The developed devices have shown increased sensitivity and decreased detection limits between other improvements of analytical performance data. The phenomena behind nanomaterials responses are also discussed and some typical responses data of the developed systems either in standard solutions or in real samples are given. The developed nanomaterials based electrochemical systems are giving new inputs to the existing devices or leading to the development of novel heavy metal detection tools with interest for applications in field such as diagnostics, environmental and safety and security controls or other industries.

  14. Electrochemical sensing carcinogens in beverages

    CERN Document Server

    Zia, Asif Iqbal

    2016-01-01

    This book describes a robust, low-cost electrochemical sensing system that is able to detect hormones and phthalates – the most ubiquitous endocrine disruptor compounds – in beverages and is sufficiently flexible to be readily coupled with any existing chemical or biochemical sensing system. A novel type of silicon substrate-based smart interdigital transducer, developed using MEMS semiconductor fabrication technology, is employed in conjunction with electrochemical impedance spectroscopy to allow real-time detection and analysis. Furthermore, the presented interdigital capacitive sensor design offers a sufficient penetration depth of the fringing electric field to permit bulk sample testing. The authors address all aspects of the development of the system and fully explain its benefits. The book will be of wide interest to engineers, scientists, and researchers working in the fields of physical electrochemistry and biochemistry at the undergraduate, postgraduate, and research levels. It will also be high...

  15. 3D printed stretchable capacitive sensors for highly sensitive tactile and electrochemical sensing

    Science.gov (United States)

    Li, Kai; Wei, Hong; Liu, Wenguang; Meng, Hong; Zhang, Peixin; Yan, Chaoyi

    2018-05-01

    Developments of innovative strategies for the fabrication of stretchable sensors are of crucial importance for their applications in wearable electronic systems. In this work, we report the successful fabrication of stretchable capacitive sensors using a novel 3D printing method for highly sensitive tactile and electrochemical sensing applications. Unlike conventional lithographic or templated methods, the programmable 3D printing technique can fabricate complex device structures in a cost-effective and facile manner. We designed and fabricated stretchable capacitive sensors with interdigital and double-vortex designs and demonstrated their successful applications as tactile and electrochemical sensors. Especially, our stretchable sensors exhibited a detection limit as low as 1 × 10-6 M for NaCl aqueous solution, which could have significant potential applications when integrated in electronics skins.

  16. Phosphorus doped and defects engineered graphene for improved electrochemical sensing: synergistic effect of dopants and defects

    International Nuclear Information System (INIS)

    Chu, Ke; Wang, Fan; Tian, Ye; Wei, Zhen

    2017-01-01

    Heteroatom-doped graphene materials emerged as promising metal-free catalysts have recently attracted a growing interest in electrochemical sensing applications. However, their catalytic activity and sensing performances still need to be further improved. Herein, we reported the development of unique phosphorus (P)-doped and plasma-etched graphene (denoted as PG-E) as an efficient metal-free electrocatalyst for dopamine (DA) sensing. It was demonstrated that introducing both P-dopants and plasma-engineered defects in graphene could synergistically improve the activity toward electrocatalytic oxidation of DA by increasing the accessible active sites and promoting the electron transport capability. The resulting PG-E modified electrode showed exceptional DA sensing performances with low detection limit, high selectivity and good stability. These results suggested that the synergistic effect of dopants and defects might be an important factor for developing the advanced graphene-based metal-free catalysts for electrochemical sensing.

  17. Nanostructured layer-by-layer films containing phaeophytin-b: Electrochemical characterization for sensing purposes

    International Nuclear Information System (INIS)

    Nunes Pauli, Gisele Elias; Araruna, Felipe B.; Eiras, Carla; Leite, José Roberto S.A.; Chaves, Otemberg Souza; Filho, Severino Gonçalves Brito; Vanderlei de Souza, Maria de Fátima; Chavero, Lucas Natálio; Sartorelli, Maria Luisa

    2015-01-01

    This paper reports the study and characterization of a new platform for practical applications, where the use of phaeophytin-b (phaeo-b), a compound derived from chlorophyll, was characterized and investigated for sensing purposes. Modified electrodes with nanostructured phaeo-b films were fabricated via the layer-by-layer (LbL) technique, where phaeo-b was assembled with cashew gum, a polysaccharide, or with poly(allylamine) hydrochloride (PAH). The multilayer formation was investigated with UV–Vis spectroscopy by monitoring the absorption band associated to phaeo-b at approximately 410 nm, where distinct molecular interactions between the materials were verified. The morphology of the films was analyzed by atomic force microscopy (AFM). The electrochemical properties through redox behavior of phaeo-b were studied with cyclic voltammetry. The produced films were applied as sensors for hydrogen peroxide (H 2 O 2 ) detection. In terms of sensing, the cashew/phaeo-b film exhibited the most promising result, with a fast response and broad linear range upon the addition of H 2 O 2 . This approach provides a simple and inexpensive method for development of a nonenzymatic electrochemical sensor for H 2 O 2 . - Highlights: • Potential applications of phaeophytin-b • Low-cost method to produce sensitive nanostructured films • Electrochemical sensor based on phaeophytin-b and cashew gum

  18. Aptamer-Based Electrochemical Sensing of Lysozyme

    Directory of Open Access Journals (Sweden)

    Alina Vasilescu

    2016-06-01

    Full Text Available Protein analysis and quantification are required daily by thousands of laboratories worldwide for activities ranging from protein characterization to clinical diagnostics. Multiple factors have to be considered when selecting the best detection and quantification assay, including the amount of protein available, its concentration, the presence of interfering molecules, as well as costs and rapidity. This is also the case for lysozyme, a 14.3-kDa protein ubiquitously present in many organisms, that has been identified with a variety of functions: antibacterial activity, a biomarker of several serious medical conditions, a potential allergen in foods or a model of amyloid-type protein aggregation. Since the design of the first lysozyme aptamer in 2001, lysozyme became one of the most intensively-investigated biological target analytes for the design of novel biosensing concepts, particularly with regards to electrochemical aptasensors. In this review, we discuss the state of the art of aptamer-based electrochemical sensing of lysozyme, with emphasis on sensing in serum and real samples.

  19. The Binding Effect of Proteins on Medications and Its Impact on Electrochemical Sensing: Antipsychotic Clozapine as a Case Study

    Directory of Open Access Journals (Sweden)

    George E. Banis

    2017-08-01

    Full Text Available Clozapine (CLZ, a dibenzodiazepine, is demonstrated as the optimal antipsychotic for patients suffering from treatment-resistant schizophrenia. Like many other drugs, understanding the concentration of CLZ in a patient’s blood is critical for managing the patients’ symptoms, side effects, and overall treatment efficacy. To that end, various electrochemical techniques have been adapted due to their capabilities in concentration-dependent sensing. An open question associated with electrochemical CLZ monitoring is whether drug–protein complexes (i.e., CLZ bound to native blood proteins, such as serum albumin (SA or alpha-1 acid-glycoprotein (AAG contribute to electrochemical redox signals. Here, we investigate CLZ-sensing performance using fundamental electrochemical methods with respect to the impact of protein binding. Specifically, we test the activity of bound and free fractions of a mixture of CLZ and either bovine SA or human AAG. Results suggest that bound complexes do not significantly contribute to the electrochemical signal for mixtures of CLZ with AAG or SA. Moreover, the fraction of CLZ bound to protein is relatively constant at 31% (AAG and 73% (SA in isolation with varying concentrations of CLZ. Thus, electrochemical sensing can enable direct monitoring of only the unbound CLZ, previously only accessible via equilibrium dialysis. The methods utilized in this work offer potential as a blueprint in developing electrochemical sensors for application to other redox-active medications with high protein binding more generally. This demonstrates that electrochemical sensing can be a new tool in accessing information not easily available previously, useful toward optimizing treatment regimens.

  20. Nanostructured layer-by-layer films containing phaeophytin-b: Electrochemical characterization for sensing purposes

    Energy Technology Data Exchange (ETDEWEB)

    Nunes Pauli, Gisele Elias [Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, SC 88040900 (Brazil); Araruna, Felipe B. [Núcleo de Pesquisa em Biodiversidade e Biotecnologia, BIOTEC, Campus Ministro Reis Velloso, CMRV, Universidade Federal do Piauí, UFPI, Parnaíba (Brazil); Eiras, Carla [Núcleo de Pesquisa em Biodiversidade e Biotecnologia, BIOTEC, Campus Ministro Reis Velloso, CMRV, Universidade Federal do Piauí, UFPI, Parnaíba (Brazil); Laboratório Interdisciplinar de Materiais Avançados, LIMAV, CCN, UFPI, Teresina, PI 64049-550 (Brazil); Leite, José Roberto S.A. [Núcleo de Pesquisa em Biodiversidade e Biotecnologia, BIOTEC, Campus Ministro Reis Velloso, CMRV, Universidade Federal do Piauí, UFPI, Parnaíba (Brazil); Chaves, Otemberg Souza; Filho, Severino Gonçalves Brito; Vanderlei de Souza, Maria de Fátima [Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Universidade Federal da Paraíba, 58051-970 João Pessoa, Paraíba (Brazil); Chavero, Lucas Natálio; Sartorelli, Maria Luisa [Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, SC 88040900 (Brazil); and others

    2015-02-01

    This paper reports the study and characterization of a new platform for practical applications, where the use of phaeophytin-b (phaeo-b), a compound derived from chlorophyll, was characterized and investigated for sensing purposes. Modified electrodes with nanostructured phaeo-b films were fabricated via the layer-by-layer (LbL) technique, where phaeo-b was assembled with cashew gum, a polysaccharide, or with poly(allylamine) hydrochloride (PAH). The multilayer formation was investigated with UV–Vis spectroscopy by monitoring the absorption band associated to phaeo-b at approximately 410 nm, where distinct molecular interactions between the materials were verified. The morphology of the films was analyzed by atomic force microscopy (AFM). The electrochemical properties through redox behavior of phaeo-b were studied with cyclic voltammetry. The produced films were applied as sensors for hydrogen peroxide (H{sub 2}O{sub 2}) detection. In terms of sensing, the cashew/phaeo-b film exhibited the most promising result, with a fast response and broad linear range upon the addition of H{sub 2}O{sub 2}. This approach provides a simple and inexpensive method for development of a nonenzymatic electrochemical sensor for H{sub 2}O{sub 2}. - Highlights: • Potential applications of phaeophytin-b • Low-cost method to produce sensitive nanostructured films • Electrochemical sensor based on phaeophytin-b and cashew gum.

  1. Electrochemical Fabrication of Nanostructures on Porous Silicon for Biochemical Sensing Platforms.

    Science.gov (United States)

    Ko, Euna; Hwang, Joonki; Kim, Ji Hye; Lee, Joo Heon; Lee, Sung Hwan; Tran, Van-Khue; Chung, Woo Sung; Park, Chan Ho; Choo, Jaebum; Seong, Gi Hun

    2016-01-01

    We present a method for the electrochemical patterning of gold nanoparticles (AuNPs) or silver nanoparticles (AgNPs) on porous silicon, and explore their applications in: (1) the quantitative analysis of hydroxylamine as a chemical sensing electrode and (2) as a highly sensitive surface-enhanced Raman spectroscopy (SERS) substrate for Rhodamine 6G. For hydroxylamine detection, AuNPs-porous silicon can enhance the electrochemical oxidation of hydroxylamine. The current changed linearly for concentrations ranging from 100 μM to 1.32 mM (R(2) = 0.995), and the detection limit was determined to be as low as 55 μM. When used as SERS substrates, these materials also showed that nanoparticles decorated on porous silicon substrates have more SERS hot spots than those decorated on crystalline silicon substrates, resulting in a larger SERS signal. Moreover, AgNPs-porous silicon provided five-times higher signal compared to AuNPs-porous silicon. From these results, we expect that nanoparticles decorated on porous silicon substrates can be used in various types of biochemical sensing platforms.

  2. Preparation, Modification, Characterization, and Biosensing Application of Nanoporous Gold Using Electrochemical Techniques.

    Science.gov (United States)

    Bhattarai, Jay K; Neupane, Dharmendra; Nepal, Bishal; Mikhaylov, Vasilii; Demchenko, Alexei V; Stine, Keith J

    2018-03-16

    Nanoporous gold (np-Au), because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, drug delivery, biomolecules separation and purification, fuel cell development, surface-chemistry-driven actuation, and supercapacitor design. Many chemical and electrochemical procedures are known for the preparation of np-Au. Recently, researchers are focusing on easier and controlled ways to tune the pores and ligaments size of np-Au for its use in different applications. Electrochemical methods have good control over fine-tuning pore and ligament sizes. The np-Au electrodes that are prepared using electrochemical techniques are robust and are easier to handle for their use in electrochemical biosensing. Here, we review different electrochemical strategies for the preparation, post-modification, and characterization of np-Au along with the synergistic use of both electrochemistry and np-Au for applications in biosensing.

  3. Chemical Sensing Applications of ZnO Nanomaterials

    Science.gov (United States)

    Chaudhary, Savita; Umar, Ahmad; Bhasin, K. K.

    2018-01-01

    Recent advancement in nanoscience and nanotechnology has witnessed numerous triumphs of zinc oxide (ZnO) nanomaterials due to their various exotic and multifunctional properties and wide applications. As a remarkable and functional material, ZnO has attracted extensive scientific and technological attention, as it combines different properties such as high specific surface area, biocompatibility, electrochemical activities, chemical and photochemical stability, high-electron communicating features, non-toxicity, ease of syntheses, and so on. Because of its various interesting properties, ZnO nanomaterials have been used for various applications ranging from electronics to optoelectronics, sensing to biomedical and environmental applications. Further, due to the high electrochemical activities and electron communication features, ZnO nanomaterials are considered as excellent candidates for electrochemical sensors. The present review meticulously introduces the current advancements of ZnO nanomaterial-based chemical sensors. Various operational factors such as the effect of size, morphologies, compositions and their respective working mechanisms along with the selectivity, sensitivity, detection limit, stability, etc., are discussed in this article. PMID:29439528

  4. High-Resolution Graphene Films for Electrochemical Sensing via Inkjet Maskless Lithography.

    Science.gov (United States)

    Hondred, John A; Stromberg, Loreen R; Mosher, Curtis L; Claussen, Jonathan C

    2017-10-24

    Solution-phase printing of nanomaterial-based graphene inks are rapidly gaining interest for fabrication of flexible electronics. However, scalable manufacturing techniques for high-resolution printed graphene circuits are still lacking. Here, we report a patterning technique [i.e., inkjet maskless lithography (IML)] to form high-resolution, flexible, graphene films (line widths down to 20 μm) that significantly exceed the current inkjet printing resolution of graphene (line widths ∼60 μm). IML uses an inkjet printed polymer lacquer as a sacrificial pattern, viscous spin-coated graphene, and a subsequent graphene lift-off to pattern films without the need for prefabricated stencils, templates, or cleanroom technology (e.g., photolithography). Laser annealing is employed to increase conductivity on thermally sensitive, flexible substrates [polyethylene terephthalate (PET)]. Laser annealing and subsequent platinum nanoparticle deposition substantially increases the electroactive nature of graphene as illustrated by electrochemical hydrogen peroxide (H 2 O 2 ) sensing [rapid response (5 s), broad linear sensing range (0.1-550 μm), high sensitivity (0.21 μM/μA), and low detection limit (0.21 μM)]. Moreover, high-resolution, complex graphene circuits [i.e., interdigitated electrodes (IDE) with varying finger width and spacing] were created with IML and characterized via potassium chloride (KCl) electrochemical impedance spectroscopy (EIS). Results indicated that sensitivity directly correlates to electrode feature size as the IDE with the smallest finger width and spacing (50 and 50 μm) displayed the largest response to changes in KCl concentration (∼21 kΩ). These results indicate that the developed IML patterning technique is well-suited for rapid, solution-phase graphene film prototyping on flexible substrates for numerous applications including electrochemical sensing.

  5. Graphene-Paper Based Electrochemical Sensors

    DEFF Research Database (Denmark)

    Zhang, Minwei; Halder, Arnab; Cao, Xianyi

    2017-01-01

    in electrochemical sensors and energy technologies amongothers. In this chapter, we present some examples to overview recent advances in theresearch and development of two-dimensional (2D) graphene papers as new materialsfor electrochemical sensors. The chapter covers the design, fabrication, functionalizationand...... functionalization ofgraphene papers with polymer and nanoscale functional building blocks for electrochemical-sensing purposes. In terms of electrochemical-sensing applications, the emphasis ison enzyme-graphene and nanoparticle-graphene paper-based systems for the detectionof glucose. We finally conclude...

  6. Current trends in electrochemical sensing and biosensing of DNA methylation.

    Science.gov (United States)

    Krejcova, Ludmila; Richtera, Lukas; Hynek, David; Labuda, Jan; Adam, Vojtech

    2017-11-15

    DNA methylation plays an important role in physiological and pathological processes. Several genetic diseases and most malignancies tend to be associated with aberrant DNA methylation. Among other analytical methods, electrochemical approaches have been successfully employed for characterisation of DNA methylation patterns that are essential for the diagnosis and treatment of particular diseases. This article discusses current trends in the electrochemical sensing and biosensing of DNA methylation. Particularly, it provides an overview of applied electrode materials, electrode modifications and biorecognition elements applications with an emphasis on strategies that form the core DNA methylation detection approaches. The three main strategies as (i) bisulfite treatment, (ii) cleavage by restriction endonucleases, and (iii) immuno/affinity reaction were described in greater detail. Additionally, the availability of the reviewed platforms for early cancer diagnosis and the approval of methylation inhibitors for anticancer therapy were discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Preparation, Modification, Characterization, and Biosensing Application of Nanoporous Gold Using Electrochemical Techniques

    Directory of Open Access Journals (Sweden)

    Jay K. Bhattarai

    2018-03-01

    Full Text Available Nanoporous gold (np-Au, because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, drug delivery, biomolecules separation and purification, fuel cell development, surface-chemistry-driven actuation, and supercapacitor design. Many chemical and electrochemical procedures are known for the preparation of np-Au. Recently, researchers are focusing on easier and controlled ways to tune the pores and ligaments size of np-Au for its use in different applications. Electrochemical methods have good control over fine-tuning pore and ligament sizes. The np-Au electrodes that are prepared using electrochemical techniques are robust and are easier to handle for their use in electrochemical biosensing. Here, we review different electrochemical strategies for the preparation, post-modification, and characterization of np-Au along with the synergistic use of both electrochemistry and np-Au for applications in biosensing.

  8. Graphene oxide directed in-situ deposition of electroactive silver nanoparticles and its electrochemical sensing application for DNA analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Ningning [College of Chemistry and Environment, Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000 (China); Gao, Feng, E-mail: fgao1981@mnnu.edu.cn [College of Chemistry and Environment, Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000 (China); Department of Chemistry, Graduate School of Science and Engineering, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504 (Japan); He, Suyu; Zhu, Qionghua; Huang, Jiafu [College of Chemistry and Environment, Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000 (China); Tanaka, Hidekazu [Department of Chemistry, Graduate School of Science and Engineering, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504 (Japan); Wang, Qingxiang, E-mail: axiang236@126.com [College of Chemistry and Environment, Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000 (China)

    2017-01-25

    The development of high-performance biosensing platform is heavily dependent on the recognition property of the sensing layer and the output intensity of the signal probe. Herein, we present a simple and highly sensitive biosensing interface for DNA detection on the basis of graphene oxide nanosheets (GONs) directed in-situ deposition of silver nanoparticles (AgNPs). The fabrication process and electrochemical properties of the biosensing interface were probed by electrochemical techniques and scanning electron microscopy. The results indicate that GONs can specifically adsorb at the single-stranded DNA probe surface, and induces the deposition of highly electroactive AgNPs. Upon hybridization with complementary oligonucleotides to generate the duplex DNA on the electrode surface, the GONs with the deposited AgNPs will be liberated from the sensing interface due to the inferior affinity of GONs and duplex DNA, resulting in the reduction of the electrochemical signal. Such a strategy combines the superior recognition of GONs toward single-stranded DNA and double-stranded DNA, and the strong electrochemical response of in-situ deposited AgNPs. Under optimal conditions, the biosensor can detect target DNA over a wide range from 10 fM to 10 nM with a detection limit of 7.6 fM. Also, the developed biosensor shows outstanding discriminating ability toward oligonucleotides with different mismatching degrees. - Highlights: • An novel DNA biosensor was constructed based on GONs with deposited AgNPs. • GONs catalyze the in-situ deposition of AgNPs on the sensing interface. • Unique π-stacking of GONs with probe DNA contributes high selectivity of the biosensor. • High electroactivity of AgNPs leads to low detection limit (7.6 fM) for target DNA.

  9. Tunnelling conductive hybrid films of gold nanoparticles and cellulose and their applications as electrochemical electrodes

    International Nuclear Information System (INIS)

    Liu, Zhiming; Wang, Xuefeng; Wu, Wenjian; Li, Mei

    2015-01-01

    Conductive hybrid films of metal nanoparticles and polymers have practical applications in the fields of sensing, microelectronics and catalysis, etc. Herein, we present the electrochemical availability of tunnelling conductive hybrid films of gold nanoparticles (GNPs) and cellulose. The hybrid films were provided with stable tunnelling conductive properties with 12 nm GNPs of 12.7% (in weight). For the first time, the conductive hybrid films were used as substrates of electrochemical electrodes to load calmodulin (CaM) proteins for sensing of calcium cations. The electrodes of hybrid films with 20 nm GNPs of 46.7% (in weight) exhibited stable electrochemical properties, and showed significant responses to calcium cations with concentrations as low as 10 −9 M after being loaded with CaM proteins. (paper)

  10. EDTA assisted synthesis of hydroxyapatite nanoparticles for electrochemical sensing of uric acid.

    Science.gov (United States)

    Kanchana, P; Sekar, C

    2014-09-01

    Hydroxyapatite nanoparticles have been synthesized using EDTA as organic modifier by a simple microwave irradiation method and its application for the selective determination of uric acid (UA) has been demonstrated. Electrochemical behavior of uric acid at HA nanoparticle modified glassy carbon electrode (E-HA/GCE) has been investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and amperometry. The E-HA modified electrode exhibits efficient electrochemical activity towards uric acid sensing without requiring enzyme or electron mediator. Amperometry studies revealed that the fabricated electrode has excellent sensitivity for uric acid with the lowest detection limit of 142 nM over a wide concentration range from 1 × 10(-7) to 3 × 10(-5)M. Moreover, the studied E-HA modified GC electrode exhibits a good reproducibility and long-term stability and an admirable selectivity towards the determination of UA even in the presence of potential interferents. The analytical performance of this sensor was evaluated for the detection of uric acid in human urine and blood serum samples. Copyright © 2014. Published by Elsevier B.V.

  11. An electrochemical-cantilever platform for hybrid sensing applications

    DEFF Research Database (Denmark)

    Fischer, Lee MacKenzie; Dohn, Søren; Boisen, Anja

    2011-01-01

    This work presents a fully-functional, microfabricated electrochemical-cantilever hybrid platform with flow control. A new cantilever chip format is designed, fabricated, and mounted in a custom polymer flow cell. Issues such as leakage and optical/electrical access are addressed, and combined...... mechanical and electrochemical performance is investigated. Lastly, a cantilever is “defunctionalized” in situ to create a reference cantilever for differential measurements in detection of Cu2+ ions at concentrations of 10 μM and 100 nM....

  12. Synthesis of binary bismuth-cadmium oxide nanorods with sensitive electrochemical sensing performance

    International Nuclear Information System (INIS)

    Wen, Yong; Pei, Lizhai; Wei, Tian

    2017-01-01

    Binary bismuth-cadmium oxide nanorods have been synthesized by a simple hydrothermal process without templates and additives. X-ray diffraction and high-resolution transmission electron microscopy reveal that the nanorods possess single crystalline tetragonal Bi 2 CdO 4 phase. Scanning electron microscopy and transmission electron microscopy images show that the length and diameter of the nanorods are 20-300 nm and 5-10 μm, respectively. The formation of the binary bismuth-cadmium oxide nanorods is closely related to the hydrothermal parameters. The electrochemical sensing performance of the binary bismuth-cadmium oxide nanorods has been investigated using the nanorods as glassy carbon electrode modifiers. The detection limit is 0.19 μM with a linear range of 0.0005-2 mM. The nanorod-modified glassy carbon electrode exhibits good electrocatalytic activity toward L-cysteine and great application potential for electrochemical sensors.

  13. Fabrication and electrochemical characterization of multi-walled carbon nanotube electrodes for applications to nano-electrochemical sensing

    International Nuclear Information System (INIS)

    Hwang, Sookhyun; Choi, Hyonkwang; Jeon, Minhyon; Vedala, Harindra; Kim, Taehyung; Choi, Wonbong

    2010-01-01

    In this study, we fabricated and electrochemically characterized two types of individual carbon nanotube electrodes: an as-produced multi-walled carbon nanotube (MWNT) electrode and a modified MWNT electrode. As-produced MWNTs were electrically contacted with Au/Ti layers by using nanolithography and RF magnetron sputtering. Open-ended modified MWNT electrodes were fabricated by using a reactive ion etching treatment under an oxygen atmosphere. We also performed cyclic voltammetry measurements to detect aqueous dopamine solutions with different concentrations. We found that an individual MWNT electrode, which had a small effective area, showed good electrochemical performance. The electrocatalytic behavior of the modified electrode, which had 'broken' open ends were better than that of the as-produced electrode with respect to sensitivity. The modified electrode was capable of detecting dopamine at the picomolar level. Therefore, an individual modified MWNT electrode has potential for applications to active components in nanobiosensors.

  14. Sensing Properties of Multiwalled Carbon Nanotubes Grown in MW Plasma Torch: Electronic and Electrochemical Behavior, Gas Sensing, Field Emission, IR Absorption

    Directory of Open Access Journals (Sweden)

    Petra Majzlíková

    2015-01-01

    Full Text Available Vertically aligned multi-walled carbon nanotubes (VA-MWCNTs with an average diameter below 80 nm and a thickness of the uniform VA-MWCNT layer of about 16 µm were grown in microwave plasma torch and tested for selected functional properties. IR absorption important for a construction of bolometers was studied by Fourier transform infrared spectroscopy. Basic electrochemical characterization was performed by cyclic voltammetry. Comparing the obtained results with the standard or MWCNT‑modified screen-printed electrodes, the prepared VA-MWCNT electrodes indicated their high potential for the construction of electrochemical sensors. Resistive CNT gas sensor revealed a good sensitivity to ammonia taking into account room temperature operation. Field emission detected from CNTs was suitable for the pressure sensing application based on the measurement of emission current in the diode structure with bending diaphragm. The advantages of microwave plasma torch growth of CNTs, i.e., fast processing and versatility of the process, can be therefore fully exploited for the integration of surface-bound grown CNTs into various sensing structures.

  15. Paper-based electrochemical sensing platform with integral battery and electrochromic read-out.

    Science.gov (United States)

    Liu, Hong; Crooks, Richard M

    2012-03-06

    We report a battery-powered, microelectrochemical sensing platform that reports its output using an electrochromic display. The platform is fabricated based on paper fluidics and uses a Prussian blue spot electrodeposited on an indium-doped tin oxide thin film as the electrochromic indicator. The integrated metal/air battery powers both the electrochemical sensor and the electrochromic read-out, which are in electrical contact via a paper reservoir. The sample activates the battery and the presence of analyte in the sample initiates the color change of the Prussian blue spot. The entire system is assembled on the lab bench, without the need for cleanroom facilities. The applicability of the device to point-of-care sensing is demonstrated by qualitative detection of 0.1 mM glucose and H(2)O(2) in artificial urine samples.

  16. Synthesis of binary bismuth-cadmium oxide nanorods with sensitive electrochemical sensing performance

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Yong [Xinjiang Univ., Xinjiang (China). School of Civil Engineering and Architecture; Pei, Lizhai; Wei, Tian [Anhui Univ. of Technology, Anhui (China). School of Materials Science and Engineering

    2017-07-15

    Binary bismuth-cadmium oxide nanorods have been synthesized by a simple hydrothermal process without templates and additives. X-ray diffraction and high-resolution transmission electron microscopy reveal that the nanorods possess single crystalline tetragonal Bi{sub 2}CdO{sub 4} phase. Scanning electron microscopy and transmission electron microscopy images show that the length and diameter of the nanorods are 20-300 nm and 5-10 μm, respectively. The formation of the binary bismuth-cadmium oxide nanorods is closely related to the hydrothermal parameters. The electrochemical sensing performance of the binary bismuth-cadmium oxide nanorods has been investigated using the nanorods as glassy carbon electrode modifiers. The detection limit is 0.19 μM with a linear range of 0.0005-2 mM. The nanorod-modified glassy carbon electrode exhibits good electrocatalytic activity toward L-cysteine and great application potential for electrochemical sensors.

  17. Rapid and molecular selective electrochemical sensing of phthalates in aqueous solution

    KAUST Repository

    Zia, Asif I.

    2015-05-01

    Reported research work presents real time non-invasive detection of phthalates in spiked aqueous samples by employing electrochemical impedance spectroscopy (EIS) technique incorporating a novel interdigital capacitive sensor with multiple sensing thin film gold micro-electrodes fabricated on native silicon dioxide layer grown on semiconducting single crystal silicon wafer. The sensing surface was functionalized by a self-assembled monolayer of 3-aminopropyltrietoxysilane (APTES) with embedded molecular imprinted polymer (MIP) to introduce selectivity for the di(2-ethylhexyl) phthalate (DEHP) molecule. Various concentrations (1-100. ppm) of DEHP in deionized MilliQ water were tested using the functionalized sensing surface to capture the analyte. Frequency response analyzer (FRA) algorithm was used to obtain impedance spectra so as to determine sample conductance and capacitance for evaluation of phthalate concentration in the sample solution. Spectrum analysis algorithm interpreted the experimentally obtained impedance spectra by applying complex nonlinear least square (CNLS) curve fitting in order to obtain electrochemical equivalent circuit and corresponding circuit parameters describing the kinetics of the electrochemical cell. Principal component analysis was applied to deduce the effects of surface immobilized molecular imprinted polymer layer on the evaluated circuit parameters and its electrical response. The results obtained by the testing system were validated using commercially available high performance liquid chromatography diode array detector system.

  18. Molecularly engineered graphene surfaces for sensing applications: A review

    International Nuclear Information System (INIS)

    Liu, Jingquan; Liu, Zhen; Barrow, Colin J.; Yang, Wenrong

    2015-01-01

    Highlights: • The importance of surface chemistry of graphene materials is clearly described. • We discuss molecularly engineered graphene surfaces for sensing applications. • We describe the latest developments of these materials for sensing technology. - Abstract: Graphene is scientifically and commercially important because of its unique molecular structure which is monoatomic in thickness, rigorously two-dimensional and highly conjugated. Consequently, graphene exhibits exceptional electrical, optical, thermal and mechanical properties. Herein, we critically discuss the surface modification of graphene, the specific advantages that graphene-based materials can provide over other materials in sensor research and their related chemical and electrochemical properties. Furthermore, we describe the latest developments in the use of these materials for sensing technology, including chemical sensors and biosensors and their applications in security, environmental safety and diseases detection and diagnosis

  19. Molecularly engineered graphene surfaces for sensing applications: A review

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jingquan, E-mail: jliu@qdu.edu.cn [College of Chemical Science and Engineering, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao (China); Liu, Zhen; Barrow, Colin J. [Centre for Chemistry and Biotechnology, Deakin University, Geelong, VIC 3217 (Australia); Yang, Wenrong, E-mail: wenrong.yang@deakin.edu.au [Centre for Chemistry and Biotechnology, Deakin University, Geelong, VIC 3217 (Australia)

    2015-02-15

    Highlights: • The importance of surface chemistry of graphene materials is clearly described. • We discuss molecularly engineered graphene surfaces for sensing applications. • We describe the latest developments of these materials for sensing technology. - Abstract: Graphene is scientifically and commercially important because of its unique molecular structure which is monoatomic in thickness, rigorously two-dimensional and highly conjugated. Consequently, graphene exhibits exceptional electrical, optical, thermal and mechanical properties. Herein, we critically discuss the surface modification of graphene, the specific advantages that graphene-based materials can provide over other materials in sensor research and their related chemical and electrochemical properties. Furthermore, we describe the latest developments in the use of these materials for sensing technology, including chemical sensors and biosensors and their applications in security, environmental safety and diseases detection and diagnosis.

  20. A facile electrochemical intercalation and microwave assisted exfoliation methodology applied to screen-printed electrochemical-based sensing platforms to impart improved electroanalytical outputs.

    Science.gov (United States)

    Pierini, Gastón D; Foster, Christopher W; Rowley-Neale, Samuel J; Fernández, Héctor; Banks, Craig E

    2018-06-12

    Screen-printed electrodes (SPEs) are ubiquitous with the field of electrochemistry allowing researchers to translate sensors from the laboratory to the field. In this paper, we report an electrochemically driven intercalation process where an electrochemical reaction uses an electrolyte as a conductive medium as well as the intercalation source, which is followed by exfoliation and heating/drying via microwave irradiation, and applied to the working electrode of screen-printed electrodes/sensors (termed EDI-SPEs) for the first time. This novel methodology results in an increase of up to 85% of the sensor area (electrochemically active surface area, as evaluated using an outer-sphere redox probe). Upon further investigation, it is found that an increase in the electroactive area of the EDI-screen-printed based electrochemical sensing platforms is critically dependent upon the analyte and its associated electrochemical mechanism (i.e. adsorption vs. diffusion). Proof-of-concept for the electrochemical sensing of capsaicin, a measure of the hotness of chillies and chilli sauce, within both model aqueous solutions and a real sample (Tabasco sauce) is demonstrated in which the electroanalytical sensitivity (a plot of signal vs. concentration) is doubled when utilising EDI-SPEs over that of SPEs.

  1. Design and Electrochemical Study of Platinum-Based Nanomaterials for Sensitive Detection of Nitric Oxide in Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Maduraiveeran Govindhan

    2016-11-01

    Full Text Available The extensive physiological and regulatory roles of nitric oxide (NO have spurred the development of NO sensors, which are of critical importance in neuroscience and various medical applications. The development of electrochemical NO sensors is of significant importance, and has garnered a tremendous amount of attention due to their high sensitivity and selectivity, rapid response, low cost, miniaturization, and the possibility of real-time monitoring. Nanostructured platinum (Pt-based materials have attracted considerable interest regarding their use in the design of electrochemical sensors for the detection of NO, due to their unique properties and the potential for new and innovative applications. This review focuses primarily on advances and insights into the utilization of nanostructured Pt-based electrode materials, such as nanoporous Pt, Pt and PtAu nanoparticles, PtAu nanoparticle/reduced graphene oxide (rGO, and PtW nanoparticle/rGO-ionic liquid (IL nanocomposites, for the detection of NO. The design, fabrication, characterization, and integration of electrochemical NO sensing performance, selectivity, and durability are addressed. The attractive electrochemical properties of Pt-based nanomaterials have great potential for increasing the competitiveness of these new sensors and open up new opportunities in the creation of novel NO-sensing technologies for biological and medical applications.

  2. Graphene-based hybrid for enantioselective sensing applications.

    Science.gov (United States)

    Zor, Erhan; Morales-Narváez, Eden; Alpaydin, Sabri; Bingol, Haluk; Ersoz, Mustafa; Merkoçi, Arben

    2017-01-15

    Chirality is a major field of research of chemical biology and is essential in pharmacology. Accordingly, approaches for distinguishing between different chiral forms of a compound are of great interest. We report on an efficient and generic enantioselective sensor that is achieved by coupling reduced graphene oxide with γ-cyclodextrin (rGO/γ-CD). The enantioselective sensing capability of the resulting structure was operated in both electrical and optical mode for of tryptophan enantiomers (D-/L-Trp). In this sense, voltammetric and photoluminescence measurements were conducted and the experimental results were compared to molecular docking method. We gain insight into the occurring recognition mechanism with selectivity toward D- and L-Trp as shown in voltammetric, photoluminescence and molecular docking responses. As an enantioselective solid phase on an electrochemical transducer, thanks to the different dimensional interaction of enantiomers with hybrid material, a discrepancy occurs in the Gibbs free energy leading to a difference in oxidation peak potential as observed in electrochemical measurements. The optical sensing principle is based on the energy transfer phenomenon that occurs between photoexcited D-/L-Trp enantiomers and rGO/γ-CD giving rise to an enantioselective photoluminescence quenching due to the tendency of chiral enantiomers to form complexes with γ-CD in different molecular orientations as demonstrated by molecular docking studies. The approach, which is the first demonstration of applicability of molecular docking to show both enantioselective electrochemical and photoluminescence quenching capabilities of a graphene-related hybrid material, is truly new and may have broad interest in combination of experimental and computational methods for enantiosensing of chiral molecules. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Highly-sensitive electrochemical sensing platforms for food colourants based on the property-tuning of porous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Qin [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China); Xia, Shanhong; Tong, Jianhua [State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Science, Beijing, 100190 (China); Wu, Kangbing, E-mail: kbwu@hust.edu.cn [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China)

    2015-08-05

    It is very challenging to develop highly-sensitive analytical platforms for toxic synthetic colourants that widely added in food samples. Herein, a series of porous carbon (PC) was prepared using CaCO{sub 3} nanoparticles (nano-CaCO{sub 3}) as the hard template and starch as the carbon precursor. Characterizations of scanning electron microscopy and transmission electron microscopy indicated that the morphology and porous structure were controlled by the weight ratio of starch and nano-CaCO{sub 3}. The electrochemical behaviours of four kinds of widely-used food colourants, Sunset yellow, Tartrazine, Ponceau 4R and Allura red, were studied. On the surface of PC samples, the oxidation signals of colourants enhanced obviously, and more importantly, the signal enhancement abilities of PC were also dependent on the starch/nano-CaCO{sub 3} weight ratio. The greatly-increased electron transfer ability and accumulation efficiency were the main reason for the enhanced signals of colourants, as confirmed by electrochemical impedance spectroscopy and chronocoulometry. The prepared PC-2 sample by 1:1 starch/nano-CaCO{sub 3} weight ratio was more active for the oxidation of food colourtants, and increased the signals by 89.4-fold, 79.3-fold, 47.3-fold and 50.7-fold for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. As a result, a highly-sensitive electrochemical sensing platform was developed, and the detection limits were 1.4, 3.5, 2.1 and 1.7 μg L{sup −1} for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. The practical application of this new sensing platform was demonstrated using drink samples, and the detected results consisted with the values that obtained by high-performance liquid chromatography. - Highlights: • PC samples with different morphology and electrochemical activities were prepared. • Highly sensitive electrochemical sensing platform was developed for food colourants. • The accuracy and practicability was testified to be good by HPLC.

  4. Highly-sensitive electrochemical sensing platforms for food colourants based on the property-tuning of porous carbon

    International Nuclear Information System (INIS)

    Cheng, Qin; Xia, Shanhong; Tong, Jianhua; Wu, Kangbing

    2015-01-01

    It is very challenging to develop highly-sensitive analytical platforms for toxic synthetic colourants that widely added in food samples. Herein, a series of porous carbon (PC) was prepared using CaCO 3 nanoparticles (nano-CaCO 3 ) as the hard template and starch as the carbon precursor. Characterizations of scanning electron microscopy and transmission electron microscopy indicated that the morphology and porous structure were controlled by the weight ratio of starch and nano-CaCO 3 . The electrochemical behaviours of four kinds of widely-used food colourants, Sunset yellow, Tartrazine, Ponceau 4R and Allura red, were studied. On the surface of PC samples, the oxidation signals of colourants enhanced obviously, and more importantly, the signal enhancement abilities of PC were also dependent on the starch/nano-CaCO 3 weight ratio. The greatly-increased electron transfer ability and accumulation efficiency were the main reason for the enhanced signals of colourants, as confirmed by electrochemical impedance spectroscopy and chronocoulometry. The prepared PC-2 sample by 1:1 starch/nano-CaCO 3 weight ratio was more active for the oxidation of food colourtants, and increased the signals by 89.4-fold, 79.3-fold, 47.3-fold and 50.7-fold for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. As a result, a highly-sensitive electrochemical sensing platform was developed, and the detection limits were 1.4, 3.5, 2.1 and 1.7 μg L −1 for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. The practical application of this new sensing platform was demonstrated using drink samples, and the detected results consisted with the values that obtained by high-performance liquid chromatography. - Highlights: • PC samples with different morphology and electrochemical activities were prepared. • Highly sensitive electrochemical sensing platform was developed for food colourants. • The accuracy and practicability was testified to be good by HPLC

  5. Graphene prepared by one-pot solvent exfoliation as a highly sensitive platform for electrochemical sensing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Can; Cheng, Qin [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Wu, Kangbing, E-mail: kbwu@hust.edu.cn [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Wu, Gang [Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Li, Qing, E-mail: qing_li_2@brown.edu [Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-05-01

    Highlights: • Graphene was prepared by one-step solvent exfoliation as superior electrode material. • Compared with RGO, prepared graphene exhibited stronger signal enhancement. • A widespread and highly-sensitive electrochemical sensing platform was constructed. - Abstract: Graphene was easily obtained via one-step ultrasonic exfoliation of graphite powder in N-methyl-2-pyrrolidone. Scanning electron microscopy, transmission electron microscopy, Raman and particle size measurements indicated that the exfoliation efficiency and the amount of produced graphene increased with ultrasonic time. The electrochemical properties and analytical applications of the resulting graphene were systematically studied. Compared with the predominantly-used reduced graphene oxides, the obtained graphene by one-step solvent exfoliation greatly enhanced the oxidation signals of various analytes, such as ascorbic acid (AA), dopamine (DA), uric acid (UA), xanthine (XA), hypoxanthine (HXA), bisphenol A (BPA), ponceau 4R, and sunset yellow. The detection limits of AA, DA, UA, XA, HXA, BPA, ponceau 4R, and sunset yellow were evaluated to be 0.8 μM, 7.5 nM, 2.5 nM, 4 nM, 10 nM, 20 nM, 2 nM, and 1 nM, which are much lower than the reported values. Thus, the prepared graphene via solvent exfoliation strategy displays strong signal amplification ability and holds great promise in constructing a universal and sensitive electrochemical sensing platform.

  6. Nitrogen-Doped Three Dimensional Graphene for Electrochemical Sensing.

    Science.gov (United States)

    Yan, Jing; Chen, Ruwen; Liang, Qionglin; Li, Jinghong

    2015-07-01

    The rational assembly and doping of graphene play an crucial role in the improvement of electrochemical performance for analytical applications. Covalent assembly of graphene into ordered hierarchical structure provides an interconnected three dimensional conductive network and large specific area beneficial to electrolyte transfer on the electrode surface. Chemical doping with heteroatom is a powerful tool to intrinsically modify the electronic properties of graphene due to the increased free charge-carrier densities. By incorporating covalent assembly and nitrogen doping strategy, a novel nitrogen doped three dimensional reduced graphene oxide nanostructure (3D-N-RGO) was developed with synergetic enhancement in electrochemical behaviors. The as prepared 3D-N-RGO was further applied for catechol detection by differential pulse voltammetry. It exhibits much higher electrocatalytic activity towards catechol with increased peak current and decreased potential difference between the oxidation and reduction peaks. Owing to the improved electro-chemical properties, the response of the electrochemical sensor varies linearly with the catechol concentrations ranging from 5 µM to 100 µM with a detection limit of 2 µM (S/N = 3). This work is promising to open new possibilities in the study of novel graphene nanostructure and promote its potential electrochemical applications.

  7. Molybdenum disulfide nanoflower-chitosan-Au nanoparticles composites based electrochemical sensing platform for bisphenol A determination

    International Nuclear Information System (INIS)

    Huang, Ke-Jing; Liu, Yu-Jie; Liu, Yan-Ming; Wang, Ling-Ling

    2014-01-01

    Highlights: • This work constructs a novel electrochemical biosensor for bisphenol A detection. • Flower-like MoS 2 are prepared by a simple hydrothermal procedure. • AuNPs are assembled on MoS 2 nanoflowers modified electrode for signal amplification. • The developed sensor exhibits low detection limit and wide linear range. - Abstract: Two-dimensional transition metal dichalcogenide are attracting increasing attention in electrochemical sensing due to their unique electronic properties. In this work, flower-like molybdenum disulfide (MoS 2 ) was prepared by a simple hydrothermal method. The scanning electron microscopy and transmission electron microscopy images showed the MoS 2 nanoflower had sizes with diameter of about 200 nm and was constructed with many irregular sheets as a petal-like structure with thickness of several nanometers. A novel electrochemical sensor was constructed for the determination of bisphenol A (BPA) based on MoS 2 and chitosan-gold nanoparticles composites modified electrode. The sensor showed an efficient electrocatalytic role for the oxidation of BPA, and the oxidation overpotentials of BPA decreased significantly and the peak current increased greatly compared with bare GCE and other modified electrode. A good linear relationship between the oxidation peak current and BPA concentration was obtained in the range from 0.05 to 100 μM with a detection limit of 5.0 × 10 −9 M (S/N = 3). The developed sensor exhibited high sensitivity and long-term stability, and it was successfully applied for the determination of BPA in different samples. This work indicated MoS 2 nanoflowers were promising in electrochemical sensing and catalytic applications

  8. Electrochemical Sensing toward Trace As(III) Based on Mesoporous MnFe₂O₄/Au Hybrid Nanospheres Modified Glass Carbon Electrode.

    Science.gov (United States)

    Zhou, Shaofeng; Han, Xiaojuan; Fan, Honglei; Liu, Yaqing

    2016-06-22

    Au nanoparticles decorated mesoporous MnFe₂O₄ nanocrystal clusters (MnFe₂O₄/Au hybrid nanospheres) were used for the electrochemical sensing of As(III) by square wave anodic stripping voltammetry (SWASV). Modified on a cheap glass carbon electrode, these MnFe₂O₄/Au hybrid nanospheres show favorable sensitivity (0.315 μA/ppb) and limit of detection (LOD) (3.37 ppb) toward As(III) under the optimized conditions in 0.1 M NaAc-HAc (pH 5.0) by depositing for 150 s at the deposition potential of -0.9 V. No obvious interference from Cd(II) and Hg(II) was recognized during the detection of As(III). Additionally, the developed electrode displayed good reproducibility, stability, and repeatability, and offered potential practical applicability for electrochemical detection of As(III) in real water samples. The present work provides a potential method for the design of new and cheap sensors in the application of electrochemical determination toward trace As(III) and other toxic metal ions.

  9. Integrated Electrochemical Analysis System with Microfluidic and Sensing Functions

    Directory of Open Access Journals (Sweden)

    Hiroaki Suzuki

    2008-02-01

    Full Text Available An integrated device that carries out the timely transport of solutions andconducts electroanalysis was constructed. The transport of solutions was based oncapillary action in overall hydrophilic flow channels and control by valves that operateon the basis of electrowetting. Electrochemical sensors including glucose, lactate,glutamic oxaloacetic transaminase (GOT, glutamic pyruvic transaminase (GPT, pH,ammonia, urea, and creatinine were integrated. An air gap structure was used for theammonia, urea, and creatinine sensors to realize a rapid response. To enhance thetransport of ammonia that existed or was produced by the enzymatic reactions, the pHof the solution was elevated by mixing it with a NaOH solution using a valve based onelectrowetting. The sensors for GOT and GPT used a freeze-dried substrate matrix torealize rapid mixing. The sample solution was transported to required sensing sites atdesired times. The integrated sensors showed distinct responses when a sample solutionreached the respective sensing sites. Linear relationships were observed between theoutput signals and the concentration or the logarithm of the concentration of theanalytes. An interferent, L-ascorbic acid, could be eliminated electrochemically in thesample injection port.

  10. EDTA assisted synthesis of hydroxyapatite nanoparticles for electrochemical sensing of uric acid

    International Nuclear Information System (INIS)

    Kanchana, P.; Sekar, C.

    2014-01-01

    Hydroxyapatite nanoparticles have been synthesized using EDTA as organic modifier by a simple microwave irradiation method and its application for the selective determination of uric acid (UA) has been demonstrated. Electrochemical behavior of uric acid at HA nanoparticle modified glassy carbon electrode (E-HA/GCE) has been investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and amperometry. The E-HA modified electrode exhibits efficient electrochemical activity towards uric acid sensing without requiring enzyme or electron mediator. Amperometry studies revealed that the fabricated electrode has excellent sensitivity for uric acid with the lowest detection limit of 142 nM over a wide concentration range from 1 × 10 −7 to 3 × 10 −5 M. Moreover, the studied E-HA modified GC electrode exhibits a good reproducibility and long-term stability and an admirable selectivity towards the determination of UA even in the presence of potential interferents. The analytical performance of this sensor was evaluated for the detection of uric acid in human urine and blood serum samples. - Highlights: • EDTA- hydroxyapatite (HA) nanoparticles have been synthesized by microwave irradiation method. • A novel amperometric Uric Acid biosensor has been fabricated using E-HA/GCE. • The fabricated sensor exhibits a wide linear range, good stability and high reproducibility. • The sensor was applied for the detection of UA in human blood serum and urine

  11. Novel redox species polyaniline derivative-Au/Pt as sensing platform for label-free electrochemical immunoassay of carbohydrate antigen 199

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liyuan; Shan, Jiao; Feng, Feng; Ma, Zhanfang, E-mail: mazhanfang@cnu.edu.cn

    2016-03-10

    A novel electrochemical redox-active nanocomposite was synthesized by a one-pot method using N,N′-diphenyl-p-phenylediamine as monomer, and HAuCl{sub 4} and K{sub 2}PtCl{sub 4} as co-oxidizing agents. The as-prepared poly(N,N′-diphenyl-p-phenylediamine)-Au/Pt exhibited admirable electrochemical redox activity at 0.15 V, excellent H{sub 2}O{sub 2} electrocatalytic ability and favorable electron transfer ability. Based on these, the evaluation of the composite as sensing substrate for label-free electrochemical immunosensing to the sensitive detection of carbohydrate antigen 199 was described. This technique proved to be a prospective detection tool with a wide liner range from 0.001 U mL{sup −1} to 40 U mL{sup −1}, and a low detection limit of 2.3 × 10{sup −4} U mL{sup −1} (S/N = 3). In addition, this method was used for the analysis of human serum sample, and good agreement was obtained between the values and those of enzyme-linked immunosorbent assay, implying the potential application in clinical research. Importantly, the strategy of the present substrate could be extended to other polymer-based nanocomposites such as polypyrrole derivatives or polythiophene derivatives, and this could be of great significance for the electrochemical immunoassay. - Highlights: • A novel electrochemical redox composite PPPD-Au/Pt was synthesized by one-pot method. • PPPD-Au/Pt was used as sensing substrate for label-free electrochemical immunosensor. • The immunosensor showed wide detection range and ultralow detection limit for the detection of CA199.

  12. Polymer multilevel lab-on-chip systems for electrochemical sensing

    DEFF Research Database (Denmark)

    Matteucci, Marco; Larsen, Simon Tylsgaard; Garau, Alessandro

    2013-01-01

    with depths as small as tens of nanometers and as big as hundreds of microns on the same polymer chip. The authors also describe in detail the fabrication procedure of polymer substrates with embedded Au and pedot:tosylate electrodes for electrochemical applications. The electrode fabrication process...... is simple and fit for integration in a production scheme. The electrode–substrates are then bonded to injection molded counterparts to be used for electrochemical applications. A dimensional and functional characterization of the electrodes is also presented here....

  13. EDTA assisted synthesis of hydroxyapatite nanoparticles for electrochemical sensing of uric acid

    Energy Technology Data Exchange (ETDEWEB)

    Kanchana, P.; Sekar, C., E-mail: Sekar2025@gmail.com

    2014-09-01

    Hydroxyapatite nanoparticles have been synthesized using EDTA as organic modifier by a simple microwave irradiation method and its application for the selective determination of uric acid (UA) has been demonstrated. Electrochemical behavior of uric acid at HA nanoparticle modified glassy carbon electrode (E-HA/GCE) has been investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and amperometry. The E-HA modified electrode exhibits efficient electrochemical activity towards uric acid sensing without requiring enzyme or electron mediator. Amperometry studies revealed that the fabricated electrode has excellent sensitivity for uric acid with the lowest detection limit of 142 nM over a wide concentration range from 1 × 10{sup −7} to 3 × 10{sup −5} M. Moreover, the studied E-HA modified GC electrode exhibits a good reproducibility and long-term stability and an admirable selectivity towards the determination of UA even in the presence of potential interferents. The analytical performance of this sensor was evaluated for the detection of uric acid in human urine and blood serum samples. - Highlights: • EDTA- hydroxyapatite (HA) nanoparticles have been synthesized by microwave irradiation method. • A novel amperometric Uric Acid biosensor has been fabricated using E-HA/GCE. • The fabricated sensor exhibits a wide linear range, good stability and high reproducibility. • The sensor was applied for the detection of UA in human blood serum and urine.

  14. Nitrogen-doped graphene: effect of graphite oxide precursors and nitrogen content on the electrochemical sensing properties.

    Science.gov (United States)

    Megawati, Monica; Chua, Chun Kiang; Sofer, Zdenek; Klímová, Kateřina; Pumera, Martin

    2017-06-21

    Graphene, produced via chemical methods, has been widely applied for electrochemical sensing due to its structural and electrochemical properties as well as its ease of production in large quantity. While nitrogen-doped graphenes are widely studied materials, the literature showing an effect of graphene oxide preparation methods on nitrogen quantity and chemical states as well as on defects and, in turn, on electrochemical sensing is non-existent. In this study, the properties of nitrogen-doped graphene materials, prepared via hydrothermal synthesis using graphite oxide produced by various classical methods using permanganate or chlorate oxidants Staudenmaier, Hummers, Hofmann and Brodie oxidation methods, were studied; the resulting nitrogen-doped graphene oxides were labeled as ST-GO, HU-GO, HO-GO and BR-GO, respectively. The electrochemical oxidation of biomolecules, such as ascorbic acid, uric acid, dopamine, nicotinamide adenine nucleotide and DNA free bases, was carried out using cyclic voltammetry and differential pulse voltammetry techniques. The nitrogen content in doped graphene oxides increased in the order ST-GO graphene followed this trend, as shown in the cyclic voltammograms. This is a very important finding that provides insight into the electrocatalytic effect of N-doped graphene. The nitrogen-doped graphene materials exhibited improved sensitivity over bare glassy carbon for ascorbic acid, uric acid and dopamine detection. These studies will enhance our understanding of the effects of graphite oxide precursors on the electrochemical sensing properties of nitrogen-doped graphene materials.

  15. Concentric-Electrode Organic Electrochemical Transistors: Case Study for Selective Hydrazine Sensing

    Directory of Open Access Journals (Sweden)

    Sébastien Pecqueur

    2017-03-01

    Full Text Available We report on hydrazine-sensing organic electrochemical transistors (OECTs with a design consisting of concentric annular electrodes. The design engineering of these OECTs was motivated by the great potential of using OECT sensing arrays in fields such as bioelectronics. In this work, poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate (PEDOT:PSS-based OECTs have been studied as aqueous sensors that are specifically sensitive to the lethal hydrazine molecule. These amperometric sensors have many relevant features for the development of hydrazine sensors, such as a sensitivity down to 10−5 M of hydrazine in water, an order of magnitude higher selectivity for hydrazine than for nine other water-soluble common analytes, the capability to entirely recover its base signal after water flushing, and a very low operation voltage. The specificity for hydrazine to be sensed by our OECTs is caused by its catalytic oxidation at the gate electrode, and enables an increase in the output current modulation of the devices. This has permitted the device-geometry study of the whole series of 80 micrometric OECT devices with sub-20-nm PEDOT:PSS layers, channel lengths down to 1 µm, and a specific device geometry of coplanar and concentric electrodes. The numerous geometries unravel new aspects of the OECT mechanisms governing the electrochemical sensing behaviours of the device—more particularly the effect of the contacts which are inherent at the micro-scale. By lowering the device cross-talk, micrometric gate-integrated radial OECTs shall contribute to the diminishing of the readout invasiveness and therefore further promote the development of OECT biosensors.

  16. Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors

    OpenAIRE

    Kamalakanta Behera; Shubha Pandey; Anu Kadyan; Siddharth Pandey

    2015-01-01

    Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, ...

  17. Versatile charge transfer through anthraquinone films for electrochemical sensing applications

    International Nuclear Information System (INIS)

    Venarusso, Luna B.; Tammeveski, Kaido; Maia, Gilberto

    2011-01-01

    Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to study the effect of anthraquinone (AQ) films on the charge transfer rate of β-nicotinamide adenine dinucleotide (NAD + ), dopamine (DA), and ferricyanide on glassy carbon (GC) electrodes in solutions of different pH. Maximum blocking action on the Fe(CN) 6 3- redox probe was observed at pH 7 and open-circuit potential (OCP). However, maximum electron hopping effect was observed at pH 9 at both -0.58 V and -0.85 V for Fe(CN) 6 3- , pH 7 at -0.58 V for NAD + , and pH 9 at -0.58 V for DA, suggesting that electron hopping in AQ films on a GC surface is dependent on both pH and electrode potential. These findings lend support for the application of these films in the detection of soluble redox probes such as NAD + and DA at biological pH values (from 7 to 9).

  18. Current Progress of Nanomaterials in Molecularly Imprinted Electrochemical Sensing.

    Science.gov (United States)

    Zhong, Chunju; Yang, Bin; Jiang, Xinxin; Li, Jianping

    2018-01-02

    Nanomaterials have received much attention during the past decade because of their excellent optical, electronic, and catalytic properties. Nanomaterials possess high chemical reactivity, also high surface energy. Thus, provide a stable immobilization platform for biomolecules, while preserving their reactivity. Due to the conductive and catalytic properties, nanomaterials can also enhance the sensitivity of molecularly imprinted electrochemical sensors by amplifying the electrode surface, increasing the electron transfer, and catalyzing the electrochemical reactions. Molecularly imprinted polymers that contain specific molecular recognition sites can be designed for a particular target analyte. Incorporating nanomaterials into molecularly imprinted polymers is important because nanomaterials can improve the response signal, increase the sensitivity, and decrease the detection limit of the sensors. This study describes the classification of nanomaterials in molecularly imprinted polymers, their analytical properties, and their applications in the electrochemical sensors. The progress of the research on nanomaterials in molecularly imprinted polymers and the application of nanomaterials in molecularly imprinted polymers is also reviewed.

  19. Universal mobile electrochemical detector designed for use in resource-limited applications.

    Science.gov (United States)

    Nemiroski, Alex; Christodouleas, Dionysios C; Hennek, Jonathan W; Kumar, Ashok A; Maxwell, E Jane; Fernández-Abedul, Maria Teresa; Whitesides, George M

    2014-08-19

    This paper describes an inexpensive, handheld device that couples the most common forms of electrochemical analysis directly to "the cloud" using any mobile phone, for use in resource-limited settings. The device is designed to operate with a wide range of electrode formats, performs on-board mixing of samples by vibration, and transmits data over voice using audio--an approach that guarantees broad compatibility with any available mobile phone (from low-end phones to smartphones) or cellular network (second, third, and fourth generation). The electrochemical methods that we demonstrate enable quantitative, broadly applicable, and inexpensive sensing with flexibility based on a wide variety of important electroanalytical techniques (chronoamperometry, cyclic voltammetry, differential pulse voltammetry, square wave voltammetry, and potentiometry), each with different uses. Four applications demonstrate the analytical performance of the device: these involve the detection of (i) glucose in the blood for personal health, (ii) trace heavy metals (lead, cadmium, and zinc) in water for in-field environmental monitoring, (iii) sodium in urine for clinical analysis, and (iv) a malarial antigen (Plasmodium falciparum histidine-rich protein 2) for clinical research. The combination of these electrochemical capabilities in an affordable, handheld format that is compatible with any mobile phone or network worldwide guarantees that sophisticated diagnostic testing can be performed by users with a broad spectrum of needs, resources, and levels of technical expertise.

  20. Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors

    Science.gov (United States)

    Behera, Kamalakanta; Pandey, Shubha; Kadyan, Anu; Pandey, Siddharth

    2015-01-01

    Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, are currently being explored by researchers worldwide. The use of ionic liquids for the detection of carbon dioxide (CO2) gas is currently a major topic of research due to the associated importance of this gas with daily human life. This review focuses on the application of ionic liquids in optical and electrochemical CO2 sensors. The design, mechanism, sensitivity and detection limit of each type of sensor are highlighted in this review. PMID:26690155

  1. Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors.

    Science.gov (United States)

    Behera, Kamalakanta; Pandey, Shubha; Kadyan, Anu; Pandey, Siddharth

    2015-12-04

    Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, are currently being explored by researchers worldwide. The use of ionic liquids for the detection of carbon dioxide (CO₂) gas is currently a major topic of research due to the associated importance of this gas with daily human life. This review focuses on the application of ionic liquids in optical and electrochemical CO₂ sensors. The design, mechanism, sensitivity and detection limit of each type of sensor are highlighted in this review.

  2. Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors

    Directory of Open Access Journals (Sweden)

    Kamalakanta Behera

    2015-12-01

    Full Text Available Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability, ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, are currently being explored by researchers worldwide. The use of ionic liquids for the detection of carbon dioxide (CO2 gas is currently a major topic of research due to the associated importance of this gas with daily human life. This review focuses on the application of ionic liquids in optical and electrochemical CO2 sensors. The design, mechanism, sensitivity and detection limit of each type of sensor are highlighted in this review.

  3. Electrodeposition of gold-platinum alloy nanoparticles on carbon nanotubes as electrochemical sensing interface for sensitive detection of tumor marker

    Energy Technology Data Exchange (ETDEWEB)

    Li Ya [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Yuan Ruo, E-mail: yuanruo@swu.edu.cn [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Chai Yaqin; Song Zhongju [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)

    2011-07-30

    Graphical abstract: Electrodeposition of gold-platinum alloy (Au-PtNPs) on carbon nanotubes as electrochemical sensing interface and HRP as blocking agent for the fabrication of high sensitive immunosensor. Display Omitted Highlights: > In this work, we proposed a novel electrochemical sensing surface. > The sensing surface possessed larger electro-active areas and higher conductivity due to the introduction of MWCNTs. > The signal could be amplified effectively by synergetic catalysis effect of Au-PtNPs and HRP towards the reduction of H{sub 2}O{sub 2}. > Biomolecules could be immobilized on the surface of Au-PtNPs tightly with the bioactivity kept well. > The simple fabrication method provided a new potential for the future development of practical devices for clinical diagnosis application. - Abstract: A novel electrochemical sensing interface, electrodeposition of gold-platinum alloy nanoparticles (Au-PtNPs) on carbon nanotubes, was proposed and used to fabricate a label-free amperometric immunosensor. On the one hand, the multiwalled carbon nanotubes (MWCNTs) could increase active area of the electrode and enhance the electron transfer ability between the electrode and redox probe; on the other hand, the Au-PtNPs not only could be used to assemble biomolecules with bioactivity kept well, but also could further facilitate the shuttle of electrons. In the meanwhile, horseradish peroxidase (HRP) instead of bovine serum albumin (BSA) was employed to block the possible remaining active sites and avoid the nonspecific adsorption. With the synergetic catalysis effect of Au-PtNPs and HRP towards the reduction of hydrogen peroxide (H{sub 2}O{sub 2}), the signal could be amplified and the sensitivity could be enhanced. Using alpha-fetoprotein (AFP) as model analyte, the fabricated immunosensor exhibited two wide linear ranges in the concentration ranges of 0.5-20 ng mL{sup -1} and 20-200 ng mL{sup -1} with a detection limit of 0.17 ng mL{sup -1} at a signal-to-noise of

  4. Fabrication of three-dimensional carbon microelectrodes for electrochemical sensing

    DEFF Research Database (Denmark)

    Hemanth, Suhith

    Carbon microelectrodes have a wide range of applications because of their unique material properties and biocompatibility. The aim of the research work carried out in this thesis was to develop three-dimensional (3D) carbon microelectrodes for electrochemical applications. Three different fabrica...

  5. Electrochemical Sensing toward Trace As(III Based on Mesoporous MnFe2O4/Au Hybrid Nanospheres Modified Glass Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Shaofeng Zhou

    2016-06-01

    Full Text Available Au nanoparticles decorated mesoporous MnFe2O4 nanocrystal clusters (MnFe2O4/Au hybrid nanospheres were used for the electrochemical sensing of As(III by square wave anodic stripping voltammetry (SWASV. Modified on a cheap glass carbon electrode, these MnFe2O4/Au hybrid nanospheres show favorable sensitivity (0.315 μA/ppb and limit of detection (LOD (3.37 ppb toward As(III under the optimized conditions in 0.1 M NaAc-HAc (pH 5.0 by depositing for 150 s at the deposition potential of −0.9 V. No obvious interference from Cd(II and Hg(II was recognized during the detection of As(III. Additionally, the developed electrode displayed good reproducibility, stability, and repeatability, and offered potential practical applicability for electrochemical detection of As(III in real water samples. The present work provides a potential method for the design of new and cheap sensors in the application of electrochemical determination toward trace As(III and other toxic metal ions.

  6. Carbon nanotubes modified with antimony nanoparticles: A novel material for electrochemical sensing

    International Nuclear Information System (INIS)

    Moraes, Fernando C.; Cesarino, Ivana; Cesarino, Vivian; Mascaro, Lucia H.; Machado, Sergio A.S.

    2012-01-01

    Highlights: ► A novel material for the electrochemical sensing was developed. ► Sensor based CNTs modified with Sb-nanoparticles was characterised and applied. ► The proposed sensor was suitable and sensitive for the determination of bisphenol A. - Abstract: In this study, a novel material for the electrochemical determination of bisphenol A using a nanocomposite based on multi-walled carbon nanotubes modified with antimony nanoparticles has been investigated. The morphology, structure, and electrochemical performance of the nanocomposite electrodes were characterised by field emission gun scanning electron microscopy, energy-dispersive X-ray spectroscopy, and cyclic voltammetry. A scan rate study and electrochemical impedance spectroscopy showed that the bisphenol A oxidation product is adsorbed on nanocomposite electrode surface. Differential pulse voltammetry in phosphate buffer solution at pH 6, allowed the development of a method to determine bisphenol A levels in the range of 0.5–5.0 μmol L −1 , with a detection limit of 5.24 nmol L −1 (1.19 μg L −1 ).

  7. Versatile charge transfer through anthraquinone films for electrochemical sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Venarusso, Luna B. [Department of Chemistry, Universidade Federal de Mato Grosso do Sul, Caixa Postal 549, Campo Grande, MS 79070-900 (Brazil); Tammeveski, Kaido [Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu (Estonia); Maia, Gilberto, E-mail: gilberto.maia@ufms.br [Department of Chemistry, Universidade Federal de Mato Grosso do Sul, Caixa Postal 549, Campo Grande, MS 79070-900 (Brazil)

    2011-10-01

    Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to study the effect of anthraquinone (AQ) films on the charge transfer rate of {beta}-nicotinamide adenine dinucleotide (NAD{sup +}), dopamine (DA), and ferricyanide on glassy carbon (GC) electrodes in solutions of different pH. Maximum blocking action on the Fe(CN){sub 6}{sup 3-} redox probe was observed at pH 7 and open-circuit potential (OCP). However, maximum electron hopping effect was observed at pH 9 at both -0.58 V and -0.85 V for Fe(CN){sub 6}{sup 3-}, pH 7 at -0.58 V for NAD{sup +}, and pH 9 at -0.58 V for DA, suggesting that electron hopping in AQ films on a GC surface is dependent on both pH and electrode potential. These findings lend support for the application of these films in the detection of soluble redox probes such as NAD{sup +} and DA at biological pH values (from 7 to 9).

  8. Extraordinary tunable dynamic range of electrochemical aptasensor for accurate detection of ochratoxin A in food samples

    Directory of Open Access Journals (Sweden)

    Lin Cheng

    2017-06-01

    Full Text Available We report the design of a sensitive, electrochemical aptasensor for detection of ochratoxin A (OTA with an extraordinary tunable dynamic sensing range. This electrochemical aptasensor is constructed based on the target induced aptamer-folding detection mechanism and the recognition between OTA and its aptamers results in the conformational change of the aptamer probe and thus signal changes for measurement. The dynamic sensing range of the electrochemical aptasensor is successfully tuned by introduction of free assistant aptamer probes in the sensing system. Our electrochemical aptasensor shows an extraordinary dynamic sensing range of 11-order magnitude of OTA concentration from 10−8 to 102 ng/g. Of great significance, the signal response in all OTA concentration ranges is at the same current scale, demonstrating that our sensing protocol in this research could be applied for accurate detections of OTA in a broad range without using any complicated treatment of signal amplification. Finally, OTA spiked red wine and maize samples in different dynamic sensing ranges are determined with the electrochemical aptasensor under optimized sensing conditions. This tuning strategy of dynamic sensing range may offer a promising platform for electrochemical aptasensor optimizations in practical applications.

  9. Localized Electrochemiluminescence from Nanoneedle Electrodes for Very-high-density Electrochemical Sensing

    KAUST Repository

    Zhang, Jingjing

    2017-09-28

    In this paper, localized electrochemiluminescence (ECL) was visualized from nanoneedle electrodes that achieved very-high-density electrochemical sensing. The localized luminescence at the nanometer-sized tip observed was ascribed to enhanced mass transfer of the luminescence probe at the tip than on the planar surface surrounding the tip, which provided higher luminescence at the tip. The size of the luminescence spots was restricted to 15 μm permitting the electrochemical analysis with a density over 4 × 103 spots/mm2. The positive correlation between the luminescence intensity at the tips and the concentration of hydrogen peroxide supported the quantitative ECL analysis using nanoneedle electrodes. The further modification of glucose oxidase at the electrode surface conceptually demonstrated that the concentration of glucose ranging from 0.5 to 5 mM could be quantified using the luminescence at the tips, which could be further applied for the detection of multiple molecules in the complex biosystem. This successful localized ECL offers a specific strategy for the development of very-high-density electrochemical arrays without the complicated chip design.

  10. Electrochemical Sensors Based on Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Md. Aminur Rahman

    2009-03-01

    Full Text Available This review focuses on recent contributions in the development of the electrochemical sensors based on carbon nanotubes (CNTs. CNTs have unique mechanical and electronic properties, combined with chemical stability, and behave electrically as a metal or semiconductor, depending on their structure. For sensing applications, CNTs have many advantages such as small size with larger surface area, excellent electron transfer promoting ability when used as electrodes modifier in electrochemical reactions, and easy protein immobilization with retention of its activity for potential biosensors. CNTs play an important role in the performance of electrochemical biosensors, immunosensors, and DNA biosensors. Various methods have been developed for the design of sensors using CNTs in recent years. Herein we summarize the applications of CNTs in the construction of electrochemical sensors and biosensors along with other nanomaterials and conducting polymers.

  11. Fabrication of a Microneedle/CNT Hierarchical Micro/Nano Surface Electrochemical Sensor and Its In-Vitro Glucose Sensing Characterization

    Directory of Open Access Journals (Sweden)

    Youngsam Yoon

    2013-12-01

    Full Text Available We report fabrication of a microneedle-based three-electrode integrated electrochemical sensor and in-vitro characterization of this sensor for glucose sensing applications. A piece of silicon was sequentially dry and wet etched to form a 15 × 15 array of tall (approximately 380 µm sharp silicon microneedles. Iron catalyst was deposited through a SU-8 shadow mask to form the working electrode and counter electrode. A multi-walled carbon nanotube forest was grown directly on the silicon microneedle array and platinum nano-particles were electrodeposited. Silver was deposited on the Si microneedle array through another shadow mask and chlorinated to form a Ag/AgCl reference electrode. The 3-electrode electrochemical sensor was tested for various glucose concentrations in the range of 3~20 mM in 0.01 M phosphate buffered saline (PBS solution. The sensor’s amperometric response to the glucose concentration is linear and its sensitivity was found to be 17.73 ± 3 μA/mM-cm2. This microneedle-based sensor has a potential to be used for painless diabetes testing applications.

  12. Functionalization of single-walled carbon nanotubes with protein by click chemistry as sensing platform for sensitized electrochemical immunoassay

    International Nuclear Information System (INIS)

    Qi Honglan; Ling Chen; Huang Ru; Qiu Xiaoying; Shangguan Li; Gao Qiang; Zhang Chengxiao

    2012-01-01

    Highlights: ► Single-walled carbon nanotubes were functionalized with protein by click chemistry. ► The SWNTs conjugated with protein showed excellent dispersion in water and kept good bioacitvity. ► A competitive electrochemical immunoassay for the determination of anti-IgG was developed with high sensitivity and good stability. - Abstract: The application of the Cu(I)-catalyzed [3 + 2] Huisgen cycloaddition to the functionalization of single-walled carbon nanotubes (SWNTs) with the protein and the use of the artificial SWNTs as a sensing platform for sensitive immunoassay were reported. Covalent functionalization of azide decorated SWNTs with alkyne modified protein was firstly accomplished by the Cu(I)-catalyzed [3 + 2] Huisgen cycloaddition. FT-IR spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron micrograph were used to characterize the protein-functionalized SWNTs. It was found that the SWNTs conjugated with the proteins showed excellent dispersion in water and kept good bioacitivity when immunoglobulin (IgG) and horseradish peroxidase (HRP) were chosen as model proteins. As a proof-of-concept, IgG-functionalized SWNTs were immobilized onto the surface of a glassy carbon electrode by simple casting method as immunosensing platform and a sensitive competitive electrochemical immunoassay was developed for the determination of anti-immunoglobulin (anti-IgG) using HRP as enzyme label. The fabrication of the immunosensor were characterized by cyclic voltammetry and electrochemical impedance spectroscopy with the redox probe [Fe(CN) 6 ] 3−/4− . The SWNTs as immobilization platform showed better sensitizing effect, a detection limit of 30 pg mL −1 (S/N = 3) was obtained for anti-IgG. The proposed strategy provided a stable immobilization method and sensitized recognition platform for analytes. This work demonstrated that the click coupling of SWNTs with protein was an effective

  13. Electrochemical surface plasmon spectroscopy-Recent developments and applications

    International Nuclear Information System (INIS)

    Zhang, Nan; Schweiss, Ruediger; Zong, Yun; Knoll, Wolfgang

    2007-01-01

    A survey is given on recent developments and applications of electrochemical techniques combined with surface plasmon resonance (SPR) spectroscopy. Surface plasmon spectroscopy (SPS) and optical waveguide mode spectroscopy make use of evanescent waves on metal-dielectric interfaces and can be conveniently combined with electrochemical methods. Selected examples of applications of high-pressure surface electrochemical plasmon resonance spectroscopy to study supramolecular architectures such as layer-by-layer films of conducting polymers or thin composite films will be presented. Then a combination of SPS with the electrochemical quartz crystal microbalance (EQCM) will be introduced and illustrated with a study on doping/de-doping process of a conducting polymer. This combination allows for simultaneous electrochemical, optical and microgravimetric characterization of interfaces. Finally, new technical developments including integration of SPS into microfluidic devices using a grating coupler and surface plasmon enhanced diffraction will be discussed

  14. Electrochemical synthesis of poly(aniline-co-fluoroaniline) films and their application as humidity sensing material

    International Nuclear Information System (INIS)

    Sharma, Amit L.

    2009-01-01

    In the present manuscript, humidity sensing properties of a copolymer, poly(aniline-co-fluoroaniline) have been reported. The copolymer was prepared on indium-tin-oxide coated glass plates as well as platinum surface in the form of films using electrochemical technique (versus standard calomel electrode) in acidic medium. Synthesis of copolymer films was supported by Fourier transform infra-red, ultraviolet-visible, scanning electron microscope and cyclic voltammetry techniques. Molecular weight and electrical conductivity of these films were measured at different temperature. Polyaniline and poly(2-fluoroaniline) films were also synthesized using the same technique to compare the data with copolymer film. On exposure to humid atmosphere, the response behaviour of copolymer film exhibited a change in resistance with respect to relative humidity (RH). This copolymer film was found to be most sensitive in the 30-65% RH range and shows a linear behaviour with in this range.

  15. Highly-sensitive electrochemical sensing platforms for food colourants based on the property-tuning of porous carbon.

    Science.gov (United States)

    Cheng, Qin; Xia, Shanhong; Tong, Jianhua; Wu, Kangbing

    2015-08-05

    It is very challenging to develop highly-sensitive analytical platforms for toxic synthetic colourants that widely added in food samples. Herein, a series of porous carbon (PC) was prepared using CaCO3 nanoparticles (nano-CaCO3) as the hard template and starch as the carbon precursor. Characterizations of scanning electron microscopy and transmission electron microscopy indicated that the morphology and porous structure were controlled by the weight ratio of starch and nano-CaCO3. The electrochemical behaviours of four kinds of widely-used food colourants, Sunset yellow, Tartrazine, Ponceau 4R and Allura red, were studied. On the surface of PC samples, the oxidation signals of colourants enhanced obviously, and more importantly, the signal enhancement abilities of PC were also dependent on the starch/nano-CaCO3 weight ratio. The greatly-increased electron transfer ability and accumulation efficiency were the main reason for the enhanced signals of colourants, as confirmed by electrochemical impedance spectroscopy and chronocoulometry. The prepared PC-2 sample by 1:1 starch/nano-CaCO3 weight ratio was more active for the oxidation of food colourtants, and increased the signals by 89.4-fold, 79.3-fold, 47.3-fold and 50.7-fold for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. As a result, a highly-sensitive electrochemical sensing platform was developed, and the detection limits were 1.4, 3.5, 2.1 and 1.7 μg L(-1) for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. The practical application of this new sensing platform was demonstrated using drink samples, and the detected results consisted with the values that obtained by high-performance liquid chromatography. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Electrochemical immunosensors - A powerful tool for analytical applications.

    Science.gov (United States)

    Felix, Fabiana S; Angnes, Lúcio

    2018-04-15

    Immunosensors are biosensors based on interactions between an antibody and antigen on a transducer surface. Either antibody or antigen can be the species immobilized on the transducer to detect antigen or antibody, respectively. Because of the strong binding forces between these biomolecules, immunosensors present high selectivity and very high sensitivity, making them very attractive for many applications in different science fields. Electrochemical immunosensors explore measurements of an electrical signal produced on an electrochemical transductor. This signal can be voltammetric, potentiometric, conductometric or impedimetric. Immunosensors utilizing electrochemical detection have been explored in several analyses since they are specific, simple, portable, and generally disposable and can carry out in situ or automated detection. This review addresses the potential of immunosensors destined for application in food and environmental analysis, and cancer biomarker diagnosis. Emphasis is given to the approaches that have been used for construction of electrochemical immunosensors. Additionally, the fundamentals of immunosensors, technology of transducers and nanomaterials and a general overview of the possible applications of electrochemical immunosensors to the food, environmental and diseases analysis fields are described. Copyright © 2017. Published by Elsevier B.V.

  17. Improved in vivo performance of amperometric oxygen (PO2) sensing catheters via electrochemical nitric oxide generation/release.

    Science.gov (United States)

    Ren, Hang; Coughlin, Megan A; Major, Terry C; Aiello, Salvatore; Rojas Pena, Alvaro; Bartlett, Robert H; Meyerhoff, Mark E

    2015-08-18

    A novel electrochemically controlled release method for nitric oxide (NO) (based on electrochemical reduction of nitrite ions) is combined with an amperometric oxygen sensor within a dual lumen catheter configuration for the continuous in vivo sensing of the partial pressure of oxygen (PO2) in blood. The on-demand electrochemical NO generation/release method is shown to be fully compatible with amperometric PO2 sensing. The performance of the sensors is evaluated in rabbit veins and pig arteries for 7 and 21 h, respectively. Overall, the NO releasing sensors measure both venous and arterial PO2 values more accurately with an average deviation of -2 ± 11% and good correlation (R(2) = 0.97) with in vitro blood measurements, whereas the corresponding control sensors without NO release show an average deviation of -31 ± 28% and poor correlation (R(2) = 0.43) at time points >4 h after implantation in veins and >6 h in arteries. The NO releasing sensors induce less thrombus formation on the catheter surface in both veins and arteries (p < 0.05). This electrochemical NO generation/release method could offer a new and attractive means to improve the biocompatibility and performance of implantable chemical sensors.

  18. Nanomaterial-based electrochemical sensing of neurological drugs and neurotransmitters

    International Nuclear Information System (INIS)

    Sanghavi, Bankim J.; Swami, Nathan S.; Wolfbeis, Otto S.; Hirsch, Thomas

    2015-01-01

    Nanomaterial-modified detection systems represent a chief driver towards the adoption of electrochemical methods, since nanomaterials enable functional tunability, ability to self-assemble, and novel electrical, optical and catalytic properties that emerge at this scale. This results in tremendous gains in terms of sensitivity, selectivity and versatility. We review the electrochemical methods and mechanisms that may be applied to the detection of neurological drugs. We focus on understanding how specific nano-sized modifiers may be applied to influence the electron transfer event to result in gains in sensitivity, selectivity and versatility of the detection system. This critical review is structured on the basis of the Anatomical Therapeutic Chemical (ATC) Classification System, specifically ATC Code N (neurotransmitters). Specific sections are dedicated to the widely used electrodes based on the carbon materials, supporting electrolytes, and on electrochemical detection paradigms for neurological drugs and neurotransmitters within the groups referred to as ATC codes N01 to N07. We finally discuss emerging trends and future challenges such as the development of strategies for simultaneous detection of multiple targets with high spatial and temporal resolutions, the integration of microfluidic strategies for selective and localized analyte pre-concentration, the real-time monitoring of neurotransmitter secretions from active cell cultures under electro- and chemotactic cues, aptamer-based biosensors, and the miniaturization of the sensing system for detection in small sample volumes and for enabling cost savings due to manufacturing scale-up. The Electronic Supporting Material (ESM) includes review articles dealing with the review topic in last 40 years, as well as key properties of the analytes, viz., pK a values, half-life of drugs and their electrochemical mechanisms. The ESM also defines analytical figures of merit of the drugs and neurotransmitters. The

  19. Application of electrochemical techniques in fuel reprocessing- an overview

    Energy Technology Data Exchange (ETDEWEB)

    Rao, M K; Bajpai, D D; Singh, R K [Power Reactor Fuel Reprocessing Plant, Tarapur (India)

    1994-06-01

    The operating experience and development work over the past several years have considerably improved the wet chemical fuel reprocessing PUREX process and have brought the reprocessing to a stage where it is ready to adopt the introduction of electrochemical technology. Electrochemical processes offer advantages like simplification of reprocessing operation, improved performance of the plant and reduction in waste volume. At Power Reactor Fuel Reprocessing plant, Tarapur, work on development and application of electrochemical processes has been carried out in stages. To achieve plant scale application of these developments, a new electrochemical cycle is being added to PUREX process at PREFRE. This paper describes the electrochemical and membrane cell development activities carried out at PREFRE and their current status. (author). 5 refs., 4 tabs.

  20. Nanodiamond Films for Applications in Electrochemical Systems

    Directory of Open Access Journals (Sweden)

    A. F. Azevedo

    2012-01-01

    Full Text Available The purpose of the present paper is to give an overview on the current development status of nanocrystalline diamond electrodes for electrochemical applications. Firstly, we describe a brief comparison between the general properties of nanocrystalline diamond (undoped and boron-doped and boron-doped microcrystalline diamond films. This is followed by a summary of the nanodiamond preparation methods. Finally, we present a discussion about the undoped and boron-doped nanocrystalline diamond and their characteristics, electrochemical properties, and practical applications.

  1. Electrochemical and AFM Characterization of G-Quadruplex Electrochemical Biosensors and Applications

    Science.gov (United States)

    2018-01-01

    Guanine-rich DNA sequences are able to form G-quadruplexes, being involved in important biological processes and representing smart self-assembling nanomaterials that are increasingly used in DNA nanotechnology and biosensor technology. G-quadruplex electrochemical biosensors have received particular attention, since the electrochemical response is particularly sensitive to the DNA structural changes from single-stranded, double-stranded, or hairpin into a G-quadruplex configuration. Furthermore, the development of an increased number of G-quadruplex aptamers that combine the G-quadruplex stiffness and self-assembling versatility with the aptamer high specificity of binding to a variety of molecular targets allowed the construction of biosensors with increased selectivity and sensitivity. This review discusses the recent advances on the electrochemical characterization, design, and applications of G-quadruplex electrochemical biosensors in the evaluation of metal ions, G-quadruplex ligands, and other small organic molecules, proteins, and cells. The electrochemical and atomic force microscopy characterization of G-quadruplexes is presented. The incubation time and cations concentration dependence in controlling the G-quadruplex folding, stability, and nanostructures formation at carbon electrodes are discussed. Different G-quadruplex electrochemical biosensors design strategies, based on the DNA folding into a G-quadruplex, the use of G-quadruplex aptamers, or the use of hemin/G-quadruplex DNAzymes, are revisited. PMID:29666699

  2. Electrochemical Applications in Metal Bioleaching.

    Science.gov (United States)

    Tanne, Christoph Kurt; Schippers, Axel

    2017-12-10

    Biohydrometallurgy comprises the recovery of metals by biologically catalyzed metal dissolution from solids in an aqueous solution. The application of this kind of bioprocessing is described as "biomining," referring to either bioleaching or biooxidation of sulfide metal ores. Acidophilic iron- and sulfur-oxidizing microorganisms are the key to successful biomining. However, minerals such as primary copper sulfides are recalcitrant to dissolution, which is probably due to their semiconductivity or passivation effects, resulting in low reaction rates. Thus, further improvements of the bioleaching process are recommendable. Mineral sulfide dissolution is based on redox reactions and can be accomplished by electrochemical technologies. The impact of electrochemistry on biohydrometallurgy affects processing as well as analytics. Electroanalysis is still the most widely used electrochemical application in mineralogical research. Electrochemical processing can contribute to bioleaching in two ways. The first approach is the coupling of a mineral sulfide to a galvanic partner or electrocatalyst (spontaneous electron transfer). This approach requires only low energy consumption and takes place without technical installations by the addition of higher redox potential minerals (mostly pyrite), carbonic material, or electrocatalytic ions (mostly silver ions). Consequently, the processed mineral (often chalcopyrite) is preferentially dissolved. The second approach is the application of electrolytic bioreactors (controlled electron transfer). The electrochemical regulation of electrolyte properties by such reactors has found most consideration. It implies the regulation of ferrous and ferric ion ratios, which further results in optimized solution redox potential, less passivation effects, and promotion of microbial activity. However, many questions remain open and it is recommended that reactor and electrode designs are improved, with the aim of finding options for simplified

  3. Organic electrochemical transistors for cell-based impedance sensing

    International Nuclear Information System (INIS)

    Rivnay, Jonathan; Ramuz, Marc; Hama, Adel; Huerta, Miriam; Owens, Roisin M.; Leleux, Pierre

    2015-01-01

    Electrical impedance sensing of biological systems, especially cultured epithelial cell layers, is now a common technique to monitor cell motion, morphology, and cell layer/tissue integrity for high throughput toxicology screening. Existing methods to measure electrical impedance most often rely on a two electrode configuration, where low frequency signals are challenging to obtain for small devices and for tissues with high resistance, due to low current. Organic electrochemical transistors (OECTs) are conducting polymer-based devices, which have been shown to efficiently transduce and amplify low-level ionic fluxes in biological systems into electronic output signals. In this work, we combine OECT-based drain current measurements with simultaneous measurement of more traditional impedance sensing using the gate current to produce complex impedance traces, which show low error at both low and high frequencies. We apply this technique in vitro to a model epithelial tissue layer and show that the data can be fit to an equivalent circuit model yielding trans-epithelial resistance and cell layer capacitance values in agreement with literature. Importantly, the combined measurement allows for low biases across the cell layer, while still maintaining good broadband signal

  4. Aggregation of Individual Sensing Units for Signal Accumulation: Conversion of Liquid-Phase Colorimetric Assay into Enhanced Surface-Tethered Electrochemical Analysis.

    Science.gov (United States)

    Wei, Tianxiang; Dong, Tingting; Wang, Zhaoyin; Bao, Jianchun; Tu, Wenwen; Dai, Zhihui

    2015-07-22

    A novel concept is proposed for converting liquid-phase colorimetric assay into enhanced surface-tethered electrochemical analysis, which is based on the analyte-induced formation of a network architecture of metal nanoparticles (MNs). In a proof-of-concept trial, thymine-functionalized silver nanoparticle (Ag-T) is designed as the sensing unit for Hg(2+) determination. Through a specific T-Hg(2+)-T coordination, the validation system based on functionalized sensing units not only can perform well in a colorimetric Hg(2+) assay, but also can be developed into a more sensitive and stable electrochemical Hg(2+) sensor. In electrochemical analysis, the simple principle of analyte-induced aggregation of MNs can be used as a dual signal amplification strategy for significantly improving the detection sensitivity. More importantly, those numerous and diverse colorimetric assays that rely on the target-induced aggregation of MNs can be augmented to satisfy the ambitious demands of sensitive analysis by converting them into electrochemical assays via this approach.

  5. The Current Status of Hydrogen Storage Alloy Development for Electrochemical Applications

    Science.gov (United States)

    Young, Kwo-hsiung; Nei, Jean

    2013-01-01

    In this review article, the fundamentals of electrochemical reactions involving metal hydrides are explained, followed by a report of recent progress in hydrogen storage alloys for electrochemical applications. The status of various alloy systems, including AB5, AB2, A2B7-type, Ti-Ni-based, Mg-Ni-based, BCC, and Zr-Ni-based metal hydride alloys, for their most important electrochemical application, the nickel metal hydride battery, is summarized. Other electrochemical applications, such as Ni-hydrogen, fuel cell, Li-ion battery, air-metal hydride, and hybrid battery systems, also have been mentioned. PMID:28788349

  6. Surface functionalization of epitaxial graphene on SiC by ion irradiation for gas sensing application

    Energy Technology Data Exchange (ETDEWEB)

    Kaushik, Priya Darshni, E-mail: kaushik.priyadarshni@gmail.com [Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping (Sweden); Department of Physics, Jamia Millia Islamia, New Delhi, 110025 (India); Ivanov, Ivan G.; Lin, Pin-Cheng [Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping (Sweden); Kaur, Gurpreet [Department of Physics and Astrophysics, University of Delhi, Delhi, 110007 (India); Eriksson, Jens [Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping (Sweden); Lakshmi, G.B.V.S. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi, 110067 (India); Avasthi, D.K. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi, 110067 (India); Amity Institute of Nanotechnology, Noida 201313 (India); Gupta, Vinay [Department of Physics and Astrophysics, University of Delhi, Delhi, 110007 (India); Aziz, Anver; Siddiqui, Azher M. [Department of Physics, Jamia Millia Islamia, New Delhi, 110025 (India); Syväjärvi, Mikael [Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping (Sweden); Yazdi, G. Reza, E-mail: yazdi@ifm.liu.se [Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping (Sweden)

    2017-05-01

    Highlights: • For the first time the gas sensing application of SHI irradiated epitaxial graphene on SiC is explored. • Surface morphology of irradiated graphene layers showed graphene folding, hillocks, and formation of wrinkles. • Existence of an optimal fluence which maximize the gas sensing response towards NO{sub 2} and NH{sub 3} gases. - Abstract: In this work, surface functionalization of epitaxial graphene grown on silicon carbide was performed by ion irradiation to investigate their gas sensing capabilities. Swift heavy ion irradiation using 100 MeV silver ions at four varying fluences was implemented on epitaxial graphene to investigate morphological and structural changes and their effects on the gas sensing capabilities of graphene. Sensing devices are expected as one of the first electronic applications using graphene and most of them use functionalized surfaces to tailor a certain function. In our case, we have studied irradiation as a tool to achieve functionalization. Morphological and structural changes on epitaxial graphene layers were investigated by atomic force microscopy, Raman spectroscopy, Raman mapping and reflectance mapping. The surface morphology of irradiated graphene layers showed graphene folding, hillocks, and formation of wrinkles at highest fluence (2 × 10{sup 13} ions/cm{sup 2}). Raman spectra analysis shows that the graphene defect density is increased with increasing fluence, while Raman mapping and reflectance mapping show that there is also a reduction of monolayer graphene coverage. The samples were investigated for ammonia and nitrogen dioxide gas sensing applications. Sensors fabricated on pristine and irradiated samples showed highest gas sensing response at an optimal fluence. Our work provides new pathways for introducing defects in controlled manner in epitaxial graphene, which can be used not only for gas sensing application but also for other applications, such as electrochemical, biosensing, magnetosensing and

  7. Surface functionalization of epitaxial graphene on SiC by ion irradiation for gas sensing application

    International Nuclear Information System (INIS)

    Kaushik, Priya Darshni; Ivanov, Ivan G.; Lin, Pin-Cheng; Kaur, Gurpreet; Eriksson, Jens; Lakshmi, G.B.V.S.; Avasthi, D.K.; Gupta, Vinay; Aziz, Anver; Siddiqui, Azher M.; Syväjärvi, Mikael; Yazdi, G. Reza

    2017-01-01

    Highlights: • For the first time the gas sensing application of SHI irradiated epitaxial graphene on SiC is explored. • Surface morphology of irradiated graphene layers showed graphene folding, hillocks, and formation of wrinkles. • Existence of an optimal fluence which maximize the gas sensing response towards NO_2 and NH_3 gases. - Abstract: In this work, surface functionalization of epitaxial graphene grown on silicon carbide was performed by ion irradiation to investigate their gas sensing capabilities. Swift heavy ion irradiation using 100 MeV silver ions at four varying fluences was implemented on epitaxial graphene to investigate morphological and structural changes and their effects on the gas sensing capabilities of graphene. Sensing devices are expected as one of the first electronic applications using graphene and most of them use functionalized surfaces to tailor a certain function. In our case, we have studied irradiation as a tool to achieve functionalization. Morphological and structural changes on epitaxial graphene layers were investigated by atomic force microscopy, Raman spectroscopy, Raman mapping and reflectance mapping. The surface morphology of irradiated graphene layers showed graphene folding, hillocks, and formation of wrinkles at highest fluence (2 × 10"1"3 ions/cm"2). Raman spectra analysis shows that the graphene defect density is increased with increasing fluence, while Raman mapping and reflectance mapping show that there is also a reduction of monolayer graphene coverage. The samples were investigated for ammonia and nitrogen dioxide gas sensing applications. Sensors fabricated on pristine and irradiated samples showed highest gas sensing response at an optimal fluence. Our work provides new pathways for introducing defects in controlled manner in epitaxial graphene, which can be used not only for gas sensing application but also for other applications, such as electrochemical, biosensing, magnetosensing and spintronic

  8. A novel electrochemical sensing strategy for rapid and ultrasensitive detection of Salmonella by rolling circle amplification and DNA–AuNPs probe

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Dan; Yan, Yurong; Lei, Pinhua; Shen, Bo [Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016 (China); Cheng, Wei [Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016 (China); The Center for Clinical Molecular Medical detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Ju, Huangxian [Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016 (China); State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China); Ding, Shijia, E-mail: dingshijia@163.com [Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016 (China)

    2014-10-10

    A novel electrochemical sensing strategy was developed for ultrasensitive and rapid detection of Salmonella by combining the rolling circle amplification with DNA–AuNPs probe. - Highlights: • This paper presented a novel sensing strategy for the rapid and ultrasensitive detection for Salmonella. • Combination of rolling circle amplification and DNA–AuNPs probe is the first time for Salmonella electrochemical detection. • The method displayed excellent sensitivity and specificity for detection of Salmonella. • The fabricated biosensor was successfully applied to detect Salmonella in milk samples. - Abstract: A novel electrochemical sensing strategy was developed for ultrasensitive and rapid detection of Salmonella by combining the rolling circle amplification with DNA–AuNPs probe. The target DNA could be specifically captured by probe 1 on the sensing interface. Then the circularization mixture was added to form a typical sandwich structure. In the presence of dNTPs and phi29 DNA polymerase, the RCA was initiated to produce micrometer-long single-strand DNA. Finally, the detection probe (DNA–AuNPs) could recognize RCA product to produce enzymatic electrochemical signal. Under optimal conditions, the calibration curve of synthetic target DNA had good linearity from 10 aM to 10 pM with a detection limit of 6.76 aM (S/N = 3). The developed method had been successfully applied to detect Salmonella as low as 6 CFU mL{sup −1} in real milk sample. This proposed strategy showed great potential for clinical diagnosis, food safety and environmental monitoring.

  9. A novel electrochemical sensing strategy for rapid and ultrasensitive detection of Salmonella by rolling circle amplification and DNA–AuNPs probe

    International Nuclear Information System (INIS)

    Zhu, Dan; Yan, Yurong; Lei, Pinhua; Shen, Bo; Cheng, Wei; Ju, Huangxian; Ding, Shijia

    2014-01-01

    A novel electrochemical sensing strategy was developed for ultrasensitive and rapid detection of Salmonella by combining the rolling circle amplification with DNA–AuNPs probe. - Highlights: • This paper presented a novel sensing strategy for the rapid and ultrasensitive detection for Salmonella. • Combination of rolling circle amplification and DNA–AuNPs probe is the first time for Salmonella electrochemical detection. • The method displayed excellent sensitivity and specificity for detection of Salmonella. • The fabricated biosensor was successfully applied to detect Salmonella in milk samples. - Abstract: A novel electrochemical sensing strategy was developed for ultrasensitive and rapid detection of Salmonella by combining the rolling circle amplification with DNA–AuNPs probe. The target DNA could be specifically captured by probe 1 on the sensing interface. Then the circularization mixture was added to form a typical sandwich structure. In the presence of dNTPs and phi29 DNA polymerase, the RCA was initiated to produce micrometer-long single-strand DNA. Finally, the detection probe (DNA–AuNPs) could recognize RCA product to produce enzymatic electrochemical signal. Under optimal conditions, the calibration curve of synthetic target DNA had good linearity from 10 aM to 10 pM with a detection limit of 6.76 aM (S/N = 3). The developed method had been successfully applied to detect Salmonella as low as 6 CFU mL −1 in real milk sample. This proposed strategy showed great potential for clinical diagnosis, food safety and environmental monitoring

  10. Electrochemical Sensing, Photocatalytic and Biological Activities of ZnO Nanoparticles: Synthesis via Green Chemistry Route

    Science.gov (United States)

    Yadav, L. S. Reddy; Archana, B.; Lingaraju, K.; Kavitha, C.; Suresh, D.; Nagabhushana, H.; Nagaraju, G.

    2016-05-01

    In this paper, we have successfully synthesized ZnO nanoparticles (Nps) via solution combustion method using sugarcane juice as the novel fuel. The structure and morphology of the synthesized ZnO Nps have been analyzed using various analytical tools. The synthesized ZnO Nps exhibit excellent photocatalytic activity for the degradation of methylene blue dye, indicating that the ZnO Nps are potential photocatalytic semiconductor materials. The synthesized ZnO Nps also show good electrochemical sensing of dopamine. ZnO Nps exhibit significant bactericidal activity against Klebsiella aerogenes, Pseudomonas aeruginosa, Eschesichia coli and Staphylococcus aureus using agar well diffusion method. Furthermore, the ZnO Nps show good antioxidant activity by potentially scavenging 1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The above studies clearly demonstrate versatile applications of ZnO synthesized by simple eco-friendly route.

  11. Progress in the electrochemical modification of graphene-based materials and their applications

    International Nuclear Information System (INIS)

    Chakrabarti, M.H.; Low, C.T.J.; Brandon, N.P.; Yufit, V.; Hashim, M.A.; Irfan, M.F.; Akhtar, J.; Ruiz-Trejo, E.; Hussain, M.A.

    2013-01-01

    Highlights: • Six means of functionalizing graphene electrochemically is reviewed. • Electrochemical functionalization is relatively new to other standard methods. • The technique is expected to improve graphene's application range considerably. -- Abstract: Graphene is a 2D allotrope of carbon with exciting properties such as extremely high electronic conductivity and superior mechanical strength. It has considerable potential for applications in fields such as bio-sensors, electrochemical energy storage and electronics. In most cases, graphene has been functionalized and modified with other materials to prepare composites. This work reviews the electrochemical modification of graphene. Commencing with a brief history, a summary of several different means of modifying graphene to effect diverse applications is provided. This is followed by a discussion on different composite materials that have been prepared with reduced graphene oxide prior to moving onto a detailed consideration of six different methods of electrochemically modifying graphene to prepare composite materials. These methods involve cathodic reduction of graphene oxide, electrophoretic deposition, electro-deposition techniques, electrospinning, electrochemical doping and electrochemical polymerization. Finally a consideration on the applications of electrochemically modified graphene composite materials in various fields is presented prior to discussing some prospects in enhancing the electrochemical process to realize excellent and economic composite materials in bulk

  12. Electrochemical behaviour of carbon paste electrodes enriched with tin oxide nanoparticles using voltammetry and electrochemical impedance spectroscopy.

    Science.gov (United States)

    Muti, Mihrican; Erdem, Arzum; Caliskan, Ayfer; Sınag, Ali; Yumak, Tugrul

    2011-08-01

    The effect of the SnO(2) nanoparticles (SNPs) on the behaviour of voltammetric carbon paste electrodes were studied for possible use of this material in biosensor development. The electrochemical behaviour of SNP modified carbon paste electrodes (CPE) was first investigated by using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques. The performance of the SNP modified electrodes were compared to those of unmodified ones and the parameters affecting the response of the modified electrode were optimized. The SNP modified electrodes were then tested for the electrochemical sensing of DNA purine base adenine to explore their further development in biosensor applications. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. A review on various electrochemical techniques for heavy metal ions detection with different sensing platforms.

    Science.gov (United States)

    Bansod, BabanKumar; Kumar, Tejinder; Thakur, Ritula; Rana, Shakshi; Singh, Inderbir

    2017-08-15

    Heavy metal ions are non-biodegradable and contaminate most of the natural resources occurring in the environment including water. Some of the heavy metals including Lead (Pb), Mercury (Hg), Arsenic (As), Chromium (Cr) and Cadmium (Cd) are considered to be highly toxic and hazardous to human health even at trace levels. This leads to the requirement of fast, accurate and reliable techniques for the detection of heavy metal ions. This review presents various electrochemical detection techniques for heavy metal ions those are user friendly, low cost, provides on-site and real time monitoring as compared to other spectroscopic and optical techniques. The categorization of different electrochemical techniques is done on the basis of different types of detection signals generated due to presence of heavy metal ions in the solution matrix like current, potential, conductivity, electrochemical impedance, and electrochemiluminescence. Also, the recent trends in electrochemical detection of heavy metal ions with various types of sensing platforms including metals, metal films, metal oxides, nanomaterials, carbon nano tubes, polymers, microspheres and biomaterials have been evoked. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Nanorods of a new metal-biomolecule coordination polymer showing novel bidirectional electrocatalytic activity and excellent performance in electrochemical sensing.

    Science.gov (United States)

    Yang, Jiao; Zhou, Bo; Yao, Jie; Jiang, Xiao-Qing

    2015-05-15

    Metal organic coordination polymers (CPs), as most attractive multifunctional materials, have been studied extensively in many fields. However, metal-biomolecule CPs and CPs' electrochemical properties and applications were studied much less. We focus on this topic aiming at electrochemical biosensors with excellent performance and high biocompatibility. A new nanoscaled metal-biomolecule CP, Mn-tyr, containing manganese and tyrosine, was synthesized hydrothermally and characterized by various techniques, including XRD, TEM, EDS, EDX mapping, elemental analysis, XPS, and IR. Electrode modified with Mn-tyr showed novel bidirectional electrocatalytic ability toward both reduction and oxidation of H2O2, which might be due to Mn. With the assistance of CNTs, the sensing performance of Mn-tyr/CNTs/GCE was improved to a much higher level, with high sensitivity of 543 mA mol(-1) L cm(-2) in linear range of 1.00×10(-6)-1.02×10(-4) mol L(-1), and detection limit of 3.8×10(-7) mol L(-1). Mn-tyr/CNTs/GCE also showed fast response, high selectivity, high steadiness and reproducibility. The excellent performance implies that the metal-biomolecule CPs are promising candidates for using in enzyme-free electrochemical biosensing. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Symbiotic Sensing for Energy-Intensive Tasks in Large-Scale Mobile Sensing Applications.

    Science.gov (United States)

    Le, Duc V; Nguyen, Thuong; Scholten, Hans; Havinga, Paul J M

    2017-11-29

    Energy consumption is a critical performance and user experience metric when developing mobile sensing applications, especially with the significantly growing number of sensing applications in recent years. As proposed a decade ago when mobile applications were still not popular and most mobile operating systems were single-tasking, conventional sensing paradigms such as opportunistic sensing and participatory sensing do not explore the relationship among concurrent applications for energy-intensive tasks. In this paper, inspired by social relationships among living creatures in nature, we propose a symbiotic sensing paradigm that can conserve energy, while maintaining equivalent performance to existing paradigms. The key idea is that sensing applications should cooperatively perform common tasks to avoid acquiring the same resources multiple times. By doing so, this sensing paradigm executes sensing tasks with very little extra resource consumption and, consequently, extends battery life. To evaluate and compare the symbiotic sensing paradigm with the existing ones, we develop mathematical models in terms of the completion probability and estimated energy consumption. The quantitative evaluation results using various parameters obtained from real datasets indicate that symbiotic sensing performs better than opportunistic sensing and participatory sensing in large-scale sensing applications, such as road condition monitoring, air pollution monitoring, and city noise monitoring.

  16. Symbiotic Sensing for Energy-Intensive Tasks in Large-Scale Mobile Sensing Applications

    Science.gov (United States)

    Scholten, Hans; Havinga, Paul J. M.

    2017-01-01

    Energy consumption is a critical performance and user experience metric when developing mobile sensing applications, especially with the significantly growing number of sensing applications in recent years. As proposed a decade ago when mobile applications were still not popular and most mobile operating systems were single-tasking, conventional sensing paradigms such as opportunistic sensing and participatory sensing do not explore the relationship among concurrent applications for energy-intensive tasks. In this paper, inspired by social relationships among living creatures in nature, we propose a symbiotic sensing paradigm that can conserve energy, while maintaining equivalent performance to existing paradigms. The key idea is that sensing applications should cooperatively perform common tasks to avoid acquiring the same resources multiple times. By doing so, this sensing paradigm executes sensing tasks with very little extra resource consumption and, consequently, extends battery life. To evaluate and compare the symbiotic sensing paradigm with the existing ones, we develop mathematical models in terms of the completion probability and estimated energy consumption. The quantitative evaluation results using various parameters obtained from real datasets indicate that symbiotic sensing performs better than opportunistic sensing and participatory sensing in large-scale sensing applications, such as road condition monitoring, air pollution monitoring, and city noise monitoring. PMID:29186037

  17. Symbiotic Sensing for Energy-Intensive Tasks in Large-Scale Mobile Sensing Applications

    Directory of Open Access Journals (Sweden)

    Duc V. Le

    2017-11-01

    Full Text Available Energy consumption is a critical performance and user experience metric when developing mobile sensing applications, especially with the significantly growing number of sensing applications in recent years. As proposed a decade ago when mobile applications were still not popular and most mobile operating systems were single-tasking, conventional sensing paradigms such as opportunistic sensing and participatory sensing do not explore the relationship among concurrent applications for energy-intensive tasks. In this paper, inspired by social relationships among living creatures in nature, we propose a symbiotic sensing paradigm that can conserve energy, while maintaining equivalent performance to existing paradigms. The key idea is that sensing applications should cooperatively perform common tasks to avoid acquiring the same resources multiple times. By doing so, this sensing paradigm executes sensing tasks with very little extra resource consumption and, consequently, extends battery life. To evaluate and compare the symbiotic sensing paradigm with the existing ones, we develop mathematical models in terms of the completion probability and estimated energy consumption. The quantitative evaluation results using various parameters obtained from real datasets indicate that symbiotic sensing performs better than opportunistic sensing and participatory sensing in large-scale sensing applications, such as road condition monitoring, air pollution monitoring, and city noise monitoring.

  18. Nanomaterials for electrochemical sensing and biosensing

    CERN Document Server

    Pumera, Martin

    2014-01-01

    Part 1: Nanomaterial-Based ElectrodesCarbon Nanotube-Based Electrochemical Sensors and Biosensors, Martin Pumera, National Institute for Materials Science, JapanElectrochemistry on Single Carbon Nanotube, Pat Collier, Caltech, USATheory of Voltammetry at Nanoparticle-Modified Electrodes, Richard G. Compton, Oxford University, UKMetal Oxide Nanoparticle-Modified Electrodes, Frank Marken, University of Bath, UKSemiconductor Quantum Dots for Electrochemical Bioanalysis, Eugenii Katz, Clarkson University, USAN

  19. Detection of Hepatitis C core antibody by dual-affinity yeast chimera and smartphone-based electrochemical sensing.

    Science.gov (United States)

    Aronoff-Spencer, Eliah; Venkatesh, A G; Sun, Alex; Brickner, Howard; Looney, David; Hall, Drew A

    2016-12-15

    Yeast cell lines were genetically engineered to display Hepatitis C virus (HCV) core antigen linked to gold binding peptide (GBP) as a dual-affinity biobrick chimera. These multifunctional yeast cells adhere to the gold sensor surface while simultaneously acting as a "renewable" capture reagent for anti-HCV core antibody. This streamlined functionalization and detection strategy removes the need for traditional purification and immobilization techniques. With this biobrick construct, both optical and electrochemical immunoassays were developed. The optical immunoassays demonstrated detection of anti-HCV core antibody down to 12.3pM concentrations while the electrochemical assay demonstrated higher binding constants and dynamic range. The electrochemical format and a custom, low-cost smartphone-based potentiostat ($20 USD) yielded comparable results to assays performed on a state-of-the-art electrochemical workstation. We propose this combination of synthetic biology and scalable, point-of-care sensing has potential to provide low-cost, cutting edge diagnostic capability for many pathogens in a variety of settings. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Development and characterization of electrochemical cantilever sensor for bio/chemical sensing applications

    DEFF Research Database (Denmark)

    Quan, Xueling; Fischer, Lee MacKenzie; Boisen, Anja

    2011-01-01

    We report the improvements made to our previously developed electrochemical cantilever (EC) sensor, where nanoporous gold material is employed as working electrodes in microcantilever arrays, while combined counter-reference electrodes are integrated on the chip. For a surface stress change of 1m...

  1. Forensic electrochemistry: indirect electrochemical sensing of the components of the new psychoactive substance "Synthacaine".

    Science.gov (United States)

    Cumba, Loanda R; Kolliopoulos, Athanasios V; Smith, Jamie P; Thompson, Paul D; Evans, Peter R; Sutcliffe, Oliver B; do Carmo, Devaney R; Banks, Craig E

    2015-08-21

    "Synthacaine" is a New Psychoactive Substance which is, due to its inherent psychoactive properties, reported to imitate the effects of cocaine and is therefore consequently branded as "legal cocaine". The only analytical approach reported to date for the sensing of "Synthacaine" is mass spectrometry. In this paper, we explore and evaluate a range of potential analytical techniques for its quantification and potential use in the field screening "Synthacaine" using Raman spectroscopy, presumptive (colour) testing, High Performance Liquid Chromatography (HPLC) and electrochemistry. HPLC analysis of street samples reveals that "Synthacaine" comprises a mixture of methiopropamine (MPA) and 2-aminoindane (2-AI). Raman spectroscopy and presumptive (colour) tests, the Marquis, Mandelin, Simon's and Robadope test, are evaluated towards a potential in-the-field screening approach but are found to not be able to discriminate between the two when they are both present in the same sample, as is the case in the real street samples. We report for the first time a novel indirect electrochemical protocol for the sensing of MPA and 2-AI which is independently validated in street samples with HPLC. This novel electrochemical approach based upon one-shot disposable cost effective screen-printed graphite macroelectrodes holds potential for in-the-field screening for "Synthacaine".

  2. Electrochemical characterization of hydrogels for biomimetic applications

    DEFF Research Database (Denmark)

    Peláez, L.; Romero, V.; Escalera, S.

    2011-01-01

    ) or a photoinitiator (P) to encapsulate and stabilize biomimetic membranes for novel separation technologies or biosensor applications. In this paper, we have investigated the electrochemical properties of the hydrogels used for membrane encapsulation. Specifically, we studied the crosslinked hydrogels by using...... electrochemical impedance spectroscopy (EIS), and we demonstrated that chemically crosslinked hydrogels had lower values for the effective electrical resistance and higher values for the electrical capacitance compared with hydrogels with photoinitiated crosslinking. Transport numbers were obtained using......〉 and 〈Pw〉 values than PEG‐1000‐DMA‐P and PEG‐400‐DA‐P hydrogels. In conclusion, our results show that hydrogel electrochemical properties can be controlled by the choice of polymer and type of crosslinking used and that their water and salt permeability properties are congruent with the use of hydrogels...

  3. Electrochemical Sensing and Assessment of Parabens in Hydro- Alcoholic Solutions and Water Using a Boron-Doped Diamond Electrode

    Directory of Open Access Journals (Sweden)

    Vasile Ostafe

    2008-07-01

    Full Text Available In this paper, the electrochemical behaviour of several parabens preservatives, i.e. esters of p-hydroxybenzoic acid, methyl-, ethyl- and propyl-4-hydroxybenzoates as methyl-, ethyl- and propyl-parabens (MB, EB, and PB, has been investigated at a commercial boron-doped diamond electrode (BDDE, especially in the anodic potential range, in both hydro-alcoholic and aqueous media. The cyclic voltammetric and chronoamperometric measurements yielded calibration plots with very good linearity (R2 between 0.990 and 0.998 and high sensitivity, useful for detection and analytical applications. The determination of the characteristics of individual compounds, of an “overall paraben index”, the assessment of the stability and the saturation solubility in water, and the amperometric sensing and determination in double distilled, tap and river water matrix of the relatively slightly soluble investigated parabens have been carried out using electrochemical alternative. Estimated water solubility was correlated with the octanol-water partition coefficient. Several ideas regarding stability and persistence of the presumptive eco-toxic investigated preservatives in the environment or water systems have been adjacently discussed.

  4. Advancement in Sensing Technology New Developments and Practical Applications

    CERN Document Server

    Jayasundera, Krishanthi; Fuchs, Anton

    2013-01-01

    The book presents the recent advancements in the area of sensors and sensing technology, specifically in environmental monitoring, structural health monitoring, dielectric, magnetic, electrochemical, ultrasonic, microfluidic, flow, surface acoustic wave, gas, cloud computing and bio-medical.   This book will be useful to a variety of readers, namely, Master and PhD degree students, researchers, practitioners, working on sensors and sensing technology. The book will provide an opportunity of a dedicated and a deep approach in order to improve their knowledge in this specific field.

  5. Fabrication of a miniaturized cell using microsystem technologies for electrochemical applications

    International Nuclear Information System (INIS)

    Lakard, Boris; Jeannot, Jean-Claude; Spajer, Michel; Herlem, Guillaume; Labachelerie, Michel de; Blind, Pascal; Fahys, Bernard

    2005-01-01

    A new type of electrochemical cell has been developed for use in electrochemical, chemical and biological applications. Using a platinum microelectrode as working electrode, this cell incorporates a silver microelectrode as reference electrode. These microelectrodes, whose area is equal to 1 μm 2 , were fabricated using photolithography, sputtering, and focused ion beam (FIB) technologies since these micro-fabrication techniques allow us to develop miniaturized electrochemical cells useful either for nanoelectrochemistry or biosensors applications. In this study, we show it is possible to coat a surface by chemical or biological compounds by immersing the microelectrodes in a solution, then setting a difference of potential between the two microelectrodes of the cell. For example, we used this miniaturized cell to realize the electrochemical polymerization of aniline into polyaniline to show that this electrochemical cell is efficient to coat a surface with a thin film of polymer

  6. Modulation of nitrogen vacancy charge state and fluorescence in nanodiamonds using electrochemical potential.

    Science.gov (United States)

    Karaveli, Sinan; Gaathon, Ophir; Wolcott, Abraham; Sakakibara, Reyu; Shemesh, Or A; Peterka, Darcy S; Boyden, Edward S; Owen, Jonathan S; Yuste, Rafael; Englund, Dirk

    2016-04-12

    The negatively charged nitrogen vacancy (NV(-)) center in diamond has attracted strong interest for a wide range of sensing and quantum information processing applications. To this end, recent work has focused on controlling the NV charge state, whose stability strongly depends on its electrostatic environment. Here, we demonstrate that the charge state and fluorescence dynamics of single NV centers in nanodiamonds with different surface terminations can be controlled by an externally applied potential difference in an electrochemical cell. The voltage dependence of the NV charge state can be used to stabilize the NV(-) state for spin-based sensing protocols and provides a method of charge state-dependent fluorescence sensing of electrochemical potentials. We detect clear NV fluorescence modulation for voltage changes down to 100 mV, with a single NV and down to 20 mV with multiple NV centers in a wide-field imaging mode. These results suggest that NV centers in nanodiamonds could enable parallel optical detection of biologically relevant electrochemical potentials.

  7. Modulation of nitrogen vacancy charge state and fluorescence in nanodiamonds using electrochemical potential

    Science.gov (United States)

    Karaveli, Sinan; Gaathon, Ophir; Wolcott, Abraham; Sakakibara, Reyu; Shemesh, Or A.; Peterka, Darcy S.; Boyden, Edward S.; Owen, Jonathan S.; Yuste, Rafael; Englund, Dirk

    2016-04-01

    The negatively charged nitrogen vacancy (NV-) center in diamond has attracted strong interest for a wide range of sensing and quantum information processing applications. To this end, recent work has focused on controlling the NV charge state, whose stability strongly depends on its electrostatic environment. Here, we demonstrate that the charge state and fluorescence dynamics of single NV centers in nanodiamonds with different surface terminations can be controlled by an externally applied potential difference in an electrochemical cell. The voltage dependence of the NV charge state can be used to stabilize the NV- state for spin-based sensing protocols and provides a method of charge state-dependent fluorescence sensing of electrochemical potentials. We detect clear NV fluorescence modulation for voltage changes down to 100 mV, with a single NV and down to 20 mV with multiple NV centers in a wide-field imaging mode. These results suggest that NV centers in nanodiamonds could enable parallel optical detection of biologically relevant electrochemical potentials.

  8. A green synthetic strategy of nickel hexacyanoferrate nanoparticals supported on the graphene substrate and its non-enzymatic amperometric sensing application

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Zhonghua, E-mail: xzh@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); He, Nan [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Rao, Honghong [College of Chemistry and Chemical Engineering, Lanzhou City University, Lanzhou, 730070 (China); Hu, Chenxian; Wang, Xiaofen; Wang, Hui; Liu, Xiuhui [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Lu, Xiaoquan, E-mail: luxq@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2017-02-28

    Highlights: • A sensitive non-enzymatic glucose sensor was explored by using a facile and green strategy. • Well dispersed and uniform NiHCF nanoparticles can be effectively produced by the introduction of electrochemical reduction graphene oxide films. • Metal hexacyanoferrate as a potential electron mediator was proposed and applied into non-enzymatic sensing. - Abstract: Rapid glucose detection is a key requirement for both diagnosis and treatment of diabetes. A facile and green strategy to achieve spherical-shaped nickel hexacyanoferrate (NiHCF) nanoparticals supported on electrochemical reduction graphene oxide by using electrochemical cyclic voltammetry is explored. As a sensing substrate, electrochemical reduction graphene oxide deposited on a glassy carbon electrode surface exhibited obvious positive effect on the electrodeposition of NiHCF nanoparticals with spherical structure and thus effectively improved the electrical conductivity and electrochemical sensing of the proposed amperometric sensor. Proof-concept experiments demonstrated that the proposed nanocomposites modified electrode exhibited excellent sensitivity toward glucose oxidation as well as with a satisfying detection limit of 0.11 μM. More importantly, we also explore that as a simple, green and facile method, electrochemical technology can be employed and provide a new strategy for developing GO and metal hexacyanoferrate based amperometric sensing platform toward glucose and other biomolecules.

  9. A green synthetic strategy of nickel hexacyanoferrate nanoparticals supported on the graphene substrate and its non-enzymatic amperometric sensing application

    International Nuclear Information System (INIS)

    Xue, Zhonghua; He, Nan; Rao, Honghong; Hu, Chenxian; Wang, Xiaofen; Wang, Hui; Liu, Xiuhui; Lu, Xiaoquan

    2017-01-01

    Highlights: • A sensitive non-enzymatic glucose sensor was explored by using a facile and green strategy. • Well dispersed and uniform NiHCF nanoparticles can be effectively produced by the introduction of electrochemical reduction graphene oxide films. • Metal hexacyanoferrate as a potential electron mediator was proposed and applied into non-enzymatic sensing. - Abstract: Rapid glucose detection is a key requirement for both diagnosis and treatment of diabetes. A facile and green strategy to achieve spherical-shaped nickel hexacyanoferrate (NiHCF) nanoparticals supported on electrochemical reduction graphene oxide by using electrochemical cyclic voltammetry is explored. As a sensing substrate, electrochemical reduction graphene oxide deposited on a glassy carbon electrode surface exhibited obvious positive effect on the electrodeposition of NiHCF nanoparticals with spherical structure and thus effectively improved the electrical conductivity and electrochemical sensing of the proposed amperometric sensor. Proof-concept experiments demonstrated that the proposed nanocomposites modified electrode exhibited excellent sensitivity toward glucose oxidation as well as with a satisfying detection limit of 0.11 μM. More importantly, we also explore that as a simple, green and facile method, electrochemical technology can be employed and provide a new strategy for developing GO and metal hexacyanoferrate based amperometric sensing platform toward glucose and other biomolecules.

  10. Printable Electrochemical Biosensors: A Focus on Screen-Printed Electrodes and Their Application

    Directory of Open Access Journals (Sweden)

    Keiichiro Yamanaka

    2016-10-01

    Full Text Available In this review we present electrochemical biosensor developments, focusing on screen-printed electrodes (SPEs and their applications. In particular, we discuss how SPEs enable simple integration, and the portability needed for on-field applications. First, we briefly discuss the general concept of biosensors and quickly move on to electrochemical biosensors. Drawing from research undertaken in this area, we cover the development of electrochemical DNA biosensors in great detail. Through specific examples, we describe the fabrication and surface modification of printed electrodes for sensitive and selective detection of targeted DNA sequences, as well as integration with reverse transcription-polymerase chain reaction (RT-PCR. For a more rounded approach, we also touch on electrochemical immunosensors and enzyme-based biosensors. Last, we present some electrochemical devices specifically developed for use with SPEs, including USB-powered compact mini potentiostat. The coupling demonstrates the practical use of printable electrode technologies for application at point-of-use. Although tremendous advances have indeed been made in this area, a few challenges remain. One of the main challenges is application of these technologies for on-field analysis, which involves complicated sample matrices.

  11. New Optical Sensing Materials for Application in Marine Research

    Science.gov (United States)

    Borisov, S.; Klimant, I.

    2012-04-01

    Optical chemosensors are versatile analytical tools which find application in numerous fields of science and technology. They proved to be a promising alternative to electrochemical methods and are applied increasingly often in marine research. However, not all state-of-the- art optical chemosensors are suitable for these demanding applications since they do not fully fulfil the requirements of high luminescence brightness, high chemical- and photochemical stability or their spectral properties are not adequate. Therefore, development of new advanced sensing materials is still of utmost importance. Here we present a set of novel optical sensing materials recently developed in the Institute of Analytical Chemistry and Food Chemistry which are optimized for marine applications. Particularly, we present new NIR indicators and sensors for oxygen and pH which feature high brightness and low level of autofluorescence. The oxygen sensors rely on highly photostable metal complexes of benzoporphyrins and azabenzoporphyrins and enable several important applications such as simultaneous monitoring of oxygen and chlorophyll or ultra-fast oxygen monitoring (Eddy correlation). We also developed ulta-sensitive oxygen optodes which enable monitoring in nM range and are primary designed for investigation of oxygen minimum zones. The dynamic range of our new NIR pH indicators based on aza-BODIPY dyes is optimized for the marine environment. A highly sensitive NIR luminescent phosphor (chromium(III) doped yttrium aluminium borate) can be used for non-invasive temperature measurements. Notably, the oxygen, pH sensors and temperature sensors are fully compatible with the commercially available fiber-optic readers (Firesting from PyroScience). An optical CO2 sensor for marine applications employs novel diketopyrrolopyrrol indicators and enables ratiometric imaging using a CCD camera. Oxygen, pH and temperature sensors suitable for lifetime and ratiometric imaging of analytes

  12. A green synthetic strategy of nickel hexacyanoferrate nanoparticals supported on the graphene substrate and its non-enzymatic amperometric sensing application

    Science.gov (United States)

    xue, Zhonghua; He, Nan; Rao, Honghong; Hu, Chenxian; Wang, Xiaofen; Wang, Hui; Liu, Xiuhui; Lu, Xiaoquan

    2017-02-01

    Rapid glucose detection is a key requirement for both diagnosis and treatment of diabetes. A facile and green strategy to achieve spherical-shaped nickel hexacyanoferrate (NiHCF) nanoparticals supported on electrochemical reduction graphene oxide by using electrochemical cyclic voltammetry is explored. As a sensing substrate, electrochemical reduction graphene oxide deposited on a glassy carbon electrode surface exhibited obvious positive effect on the electrodeposition of NiHCF nanoparticals with spherical structure and thus effectively improved the electrical conductivity and electrochemical sensing of the proposed amperometric sensor. Proof-concept experiments demonstrated that the proposed nanocomposites modified electrode exhibited excellent sensitivity toward glucose oxidation as well as with a satisfying detection limit of 0.11 μM. More importantly, we also explore that as a simple, green and facile method, electrochemical technology can be employed and provide a new strategy for developing GO and metal hexacyanoferrate based amperometric sensing platform toward glucose and other biomolecules.

  13. Electrochemical sensing of glucose by reduced graphene oxide-zinc ferrospinels

    Energy Technology Data Exchange (ETDEWEB)

    Shahnavaz, Zohreh, E-mail: zohreh.shahnavaz@siswa.um.edu.my [Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Woi, Pei Meng, E-mail: pmwoi@um.edu.my [Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Center of Ionic Liquids, University of Malaya, 50603 Kuala Lumpur (Malaysia); Alias, Yatimah, E-mail: yatimah70@um.edu.my [Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Center of Ionic Liquids, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2016-08-30

    Highlights: • A facile in situ hydrothermal method for ZnFe{sub 2}O{sub 4} nanoparticles incorporation into graphene oxide sheets. • Excellent selectivity, reproducibility and stability properties compared to others Zn-based glucose sensor. • Amount of reduced graphene oxide directly affected the electro-catalytic activity of ZnFe{sub 2}O{sub 4}/rGO nanocomposite towards glucose detection. - Abstract: We have developed ZnFe{sub 2}O{sub 4} magnetic nanoparticles/reduced graphene oxide nanosheets modified glassy carbon (ZnFe{sub 2}O{sub 4}/rGO/GCE) electrode as a novel system for the electrochemical glucose sensing. Via a facile in situ hydrothermal route, the reduction of GO and the formation of ZnFe{sub 2}O{sub 4} nanoparticles occurred simultaneously. This enables the ZnFe{sub 2}O{sub 4} nanoparticles dispersed on the reduced graphene sheet. Characterization of nanocomposite by X-ray diffraction (XRD) and transmission electron microscopy (TEM) clearly demonstrate the successful attachment of ZnFe{sub 2}O{sub 4} nanoparticles to graphene sheets. Electrochemical studies revealed that the ZnFe{sub 2}O{sub 4}/rGO/GCE possess excellent electrocatalytic activities toward the oxidation of glucose and the performance of sensor is enhanced by integration of graphene nanosheets with ZnFe{sub 2}O{sub 4} nanoparticles.

  14. Electrochemical dopamine sensor based on P-doped graphene: Highly active metal-free catalyst and metal catalyst support.

    Science.gov (United States)

    Chu, Ke; Wang, Fan; Zhao, Xiao-Lin; Wang, Xin-Wei; Tian, Ye

    2017-12-01

    Heteroatom doping is an effective strategy to enhance the catalytic activity of graphene and its hybrid materials. Despite a growing interest of P-doped graphene (P-G) in energy storage/generation applications, P-G has rarely been investigated for electrochemical sensing. Herein, we reported the employment of P-G as both metal-free catalyst and metal catalyst support for electrochemical detection of dopamine (DA). As a metal-free catalyst, P-G exhibited prominent DA sensing performances due to the important role of P doping in improving the electrocatalytic activity of graphene toward DA oxidation. Furthermore, P-G could be an efficient supporting material for loading Au nanoparticles, and resulting Au/P-G hybrid showed a dramatically enhanced electrocatalytic activity and extraordinary sensing performances with a wide linear range of 0.1-180μM and a low detection limit of 0.002μM. All these results demonstrated that P-G might be a very promising electrode material for electrochemical sensor applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Cu-Hemin Metal-Organic-Frameworks/Chitosan-Reduced Graphene Oxide Nanocomposites with Peroxidase-Like Bioactivity for Electrochemical Sensing

    International Nuclear Information System (INIS)

    Wang, Li; Yang, Han; He, Juan; Zhang, Yayun; Yu, Jie; Song, Yonghai

    2016-01-01

    Graphical abstract: A simple, sensitive and effective method to detect hydrogen peroxide based on a hybrid Cu-hemin metal-organic-frameworks (MOFs)/chitosan-functionalized reduced graphene oxide (CS-rGO) nanocomposite was achieved via Cu-hemin MOFs constructing with CS-rGO in room temperature. The Cu-hemin MOFs/CS-rGO nanomaterials exhibited a unique peroxidase-like activity and good electrical conductivity as well as some novel properties. And the as-prepared electrode resulted in a perfect electrochemical performance towards reduction of hydrogen peroxide which was superior to natural enzymes and some inorganic mimic enzymes. - Highlights: • A hybrid Cu-hemin MOF/CS-rGO with a unique peroxidase-like activity was prepared. • The CS-rGO improved electrical conductivity of the nanocomposites greatly. • The 3D porous structure enhanced the catalytic activity of hemin for H 2 O 2 . • A novel sensitive electrochemical biosensing for H 2 O 2 detection was achieved. - Abstract: Herein, a Cu-hemin metal-organic-frameworks (MOFs)/chitosan (CS)-reduced graphene oxide (CS-rGO) nanocomposite with unique peroxidase-like bioactivity and good electrical conductivity was prepared for electrochemical H 2 O 2 sensing for the first time. The prepared Cu-hemin MOFs/CS-rGO nanocomposites were well characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray powder diffraction, UV–vis spectroscopy and electrochemical techniques. The results showed that after the Cu-hemin MOFs were formed on the CS-rGO surface, the crystalline structure of the Cu-hemin MOFs was kept while the size of Cu-hemin MOFs was decreased and the electrical conductivity of the nanocomposites was enhanced greatly as compared with that of Cu-hemin MOFs. The unique peroxidase-like bioactivity and good electrical conductivity as well as some novel properties of Cu-hemin MOFs/CS-rGO nanocomposites resulted in

  16. Biomimetic supercontainers for size-selective electrochemical sensing of molecular ions

    Science.gov (United States)

    Netzer, Nathan L.; Must, Indrek; Qiao, Yupu; Zhang, Shi-Li; Wang, Zhenqiang; Zhang, Zhen

    2017-04-01

    New ionophores are essential for advancing the art of selective ion sensing. Metal-organic supercontainers (MOSCs), a new family of biomimetic coordination capsules designed using sulfonylcalix[4]arenes as container precursors, are known for their tunable molecular recognition capabilities towards an array of guests. Herein, we demonstrate the use of MOSCs as a new class of size-selective ionophores dedicated to electrochemical sensing of molecular ions. Specifically, a MOSC molecule with its cavities matching the size of methylene blue (MB+), a versatile organic molecule used for bio-recognition, was incorporated into a polymeric mixed-matrix membrane and used as an ion-selective electrode. This MOSC-incorporated electrode showed a near-Nernstian potentiometric response to MB+ in the nano- to micro-molar range. The exceptional size-selectivity was also evident through contrast studies. To demonstrate the practical utility of our approach, a simulated wastewater experiment was conducted using water from the Fyris River (Sweden). It not only showed a near-Nernstian response to MB+ but also revealed a possible method for potentiometric titration of the redox indicator. Our study thus represents a new paradigm for the rational design of ionophores that can rapidly and precisely monitor molecular ions relevant to environmental, biomedical, and other related areas.

  17. pH-switchable electrochemical sensing platform based on chitosan-reduced graphene oxide/concanavalin a layer for assay of glucose and urea.

    Science.gov (United States)

    Song, Yonghai; Liu, Hongyu; Tan, Hongliang; Xu, Fugang; Jia, Jianbo; Zhang, Lixue; Li, Zhuang; Wang, Li

    2014-02-18

    A facile and effective electrochemical sensing platform for the detection of glucose and urea in one sample without separation was developed using chitosan-reduced graphene oxide (CS-rGO)/concanavalin A (Con A) as a sensing layer. The CS-rGO/Con A with pH-dependent surface net charges exhibited pH-switchable response to negatively charged Fe(CN)6(3-). The principle for glucose and urea detection was essentially based on in situ pH-switchable enzyme-catalyzed reaction in which the oxidation of glucose catalyzed by glucose oxidase or the hydrolyzation of urea catalyzed by urease resulted in a pH change of electrolyte solution to give different electrochemical responses toward Fe(CN)6(3-). It was verified by cyclic voltammograms, differential pulse voltammograms, and electrochemical impedance spectroscopy. The resistance to charge transfer or amperometric current changed proportionally toward glucose concentration from 1.0 to 10.0 mM and urea concentration from 1.0 to 7.0 mM. On the basis of human serum experiments, the sensing platform was proved to be suitable for simultaneous assay of glucose and urea in a practical biosystem. This work not only gives a way to detect glucose and urea in one sample without separation but also provides a potential strategy for the detection of nonelectroactive species based on the enzyme-catalyzed reaction and pH-switchable biosensor.

  18. Electrochemical sensing of tumor suppressor protein p53-deoxyribonucleic acid complex stability at an electrified interface

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Černocká, Hana; Ostatná, Veronika; Navrátilová, Lucie; Brázdová, Marie

    2014-01-01

    Roč. 828, MAY2014 (2014), s. 1-8 ISSN 0003-2670 R&D Projects: GA ČR(CZ) GAP301/11/2055; GA ČR(CZ) GA13-00956S; GA ČR(CZ) GA13-36108S Institutional support: RVO:68081707 Keywords : Deoxyribonucleic acid-protein binding * Tumor suppressor protein p53 * Electrochemical sensing Subject RIV: BO - Biophysics Impact factor: 4.513, year: 2014

  19. Electrochemical non-enzymatic glucose sensors

    International Nuclear Information System (INIS)

    Park, Sejin; Boo, Hankil; Chung, Taek Dong

    2006-01-01

    The electrochemical determination of glucose concentration without using enzyme is one of the dreams that many researchers have been trying to make come true. As new materials have been reported and more knowledge on detailed mechanism of glucose oxidation has been unveiled, the non-enzymatic glucose sensor keeps coming closer to practical applications. Recent reports strongly imply that this progress will be accelerated in 'nanoera'. This article reviews the history of unraveling the mechanism of direct electrochemical oxidation of glucose and making attempts to develop successful electrochemical glucose sensors. The electrochemical oxidation of glucose molecules involves complex processes of adsorption, electron transfer, and subsequent chemical rearrangement, which are combined with the surface reactions on the metal surfaces. The information about the direct oxidation of glucose on solid-state surfaces as well as new electrode materials will lead us to possible breakthroughs in designing the enzymeless glucose sensing devices that realize innovative and powerful detection. An example of those is to introduce nanoporous platinum as an electrode, on which glucose is oxidized electrochemically with remarkable sensitivity and selectivity. Better model of such glucose sensors is sought by summarizing and revisiting the previous reports on the electrochemistry of glucose itself and new electrode materials

  20. Strategies in electro-chemical machining of tungsten for divertor application

    International Nuclear Information System (INIS)

    Krauss, W.; Holstein, N.; Konys, J.

    2007-01-01

    For future application in a fusion power system a modular structured He cooled divertor concept is investigated under the framework of EFDA which is based on the use of pure W or W alloys for the thermally highly loaded parts. Due to the underlying physico-chemical principles electro-chemical machining (ECM) is the only shaping process which will not introduce microstructural defects, e.g. microcracks into work pieces as known by example from electro-discharge machining (EDM). However, ECM processes have no industrial application in W machining up to yet due to passivation effects using standard electrolytes known from steel working. Therefore, a systematical electrochemical development program was launched, and the electrochemical behavior of W was examined and passivation effects could be eliminated, successfully. The electrochemical shaping processes can be divided into two main categories. The first one is M-ECM, which represents the lithographic route based on structured anode masks, and the other is C-ECM, working with a negatively structured cathode as tool which is copied by electro-chemical dissolution. Both ECM branches are discussed on base of first machined structured parts, showing their process depending advantages and potential enhancements are revealed by applying pulsed currents instead of DC dissolution technique

  1. Chemical modification of graphene aerogels for electrochemical capacitor applications.

    Science.gov (United States)

    Hong, Jin-Yong; Wie, Jeong Jae; Xu, Yu; Park, Ho Seok

    2015-12-14

    Graphene aerogel is a relatively new type of aerogel that is ideal for energy storage applications because of its large surface area, high electrical conductivity and good chemical stability. Also, three dimensional interconnected macropores offer many advantages such as low density, fast ion and mass transfer, and easy access to storage sites. Such features allow graphene aerogels to be intensively applied for electrochemical capacitor applications. Despite the growing interest in graphene aerogel-based electrochemical capacitors, however, the graphene aerogels still suffer from their low capacitive performances and high fragility. Both relatively low capacitance and brittleness of physically crosslinked graphene aerogels remain a critical challenge. Until now, a number of alternative attempts have been devoted to overcome these shortcomings. In this perspective, we summarize the recent research progress towards the development of advanced graphene aerogel-based electrochemical capacitors according to the different approaches (e.g. porosity, composition and structure controls). Then, the recently proposed chemical strategies to improve the capacitive performances and mechanical durability of graphene aerogels for practical applications are highlighted. Finally, the current challenges and perspectives in this emerging material are also discussed.

  2. Pyrolytic carbon microelectrodes for impedance based cell sensing

    DEFF Research Database (Denmark)

    Hassan, Yasmin Mohamed; Caviglia, Claudia; Hemanth, Suhith

    2016-01-01

    Electrically conductive glass-like carbon structures can be obtained from a polymer template through a pyrolysis process. These structures can be used as electrodes for bio sensing applications such as electrochemical evaluation of cell adhesion and proliferation. This study focuses on the optimi...... to decrease the resistivity of the resulting carbon material and improve the performance in cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Finally, EIS was used to monitor adhesion and proliferation of HeLa cells....

  3. CMOS Electrochemical Instrumentation for Biosensor Microsystems: A Review

    Directory of Open Access Journals (Sweden)

    Haitao Li

    2016-12-01

    Full Text Available Modern biosensors play a critical role in healthcare and have a quickly growing commercial market. Compared to traditional optical-based sensing, electrochemical biosensors are attractive due to superior performance in response time, cost, complexity and potential for miniaturization. To address the shortcomings of traditional benchtop electrochemical instruments, in recent years, many complementary metal oxide semiconductor (CMOS instrumentation circuits have been reported for electrochemical biosensors. This paper provides a review and analysis of CMOS electrochemical instrumentation circuits. First, important concepts in electrochemical sensing are presented from an instrumentation point of view. Then, electrochemical instrumentation circuits are organized into functional classes, and reported CMOS circuits are reviewed and analyzed to illuminate design options and performance tradeoffs. Finally, recent trends and challenges toward on-CMOS sensor integration that could enable highly miniaturized electrochemical biosensor microsystems are discussed. The information in the paper can guide next generation electrochemical sensor design.

  4. Electrochemical Machining – Special Equipment and Applications in Aircraft Industry

    Directory of Open Access Journals (Sweden)

    Ruszaj Adam

    2016-06-01

    Full Text Available Electrochemical machining is an unique method of shaping in which, for optimal parameters tool has no wear, surface layer properties after machining are similar to the core material and surface quality and accuracy increase together with material removal rate increase. Such advantages of electrochemical machining, besides of some ecological problems, create industry interest in the range of manufacturing elements made of materials with special properties (i.e. turbine blades of flow aircrafts engines. In the paper the nowadays possibilities and recent practical application of electrochemical machining in aircraft have been presented.

  5. Graphene nanoflakes on transparent glass electrode sensor for electrochemical sensing of anti-diabetic drug.

    Science.gov (United States)

    Narang, Jagriti; Malhotra, Nitesh; Singhal, Chaitali; Bhatia, Rishabh; Kathuria, Vikas; Jain, Manan

    2017-04-01

    Metformin (Mf) plays a major role in controlling insulin level of individuals at risk of developing diabetes mellitus. Overdose of Mf can cause lactic acidosis, diarrhoea, cough, or hoarseness, etc. These particulars point out the identification for selective and sensitive methods of Mf determination. In the present work, graphene nanoflakes-polymethylene blue (GNF-PMB) nano-composites were developed onto fluorine-doped tin oxide (SnO 2 /F) coated glass substrates for electrochemical sensing of Mf using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The developed sensor shows quick response time (10 s), linearity as 10-10 3  µM, LOD (0.1 nM), and good shelf life (10 weeks). Attempts have been made to utilize this electrode for estimation of Mf in urine samples. Configured as a highly responsive, reproducible Mf sensor, it combines the electrical properties of GNF and stable electron transfer of PMB. The newly developed Mf sensor presents a promising candidate in point-of-care diagnosis.

  6. Applications of Ionic Liquids in Electrochemical Sensors and Biosensors

    Directory of Open Access Journals (Sweden)

    Virendra V. Singh

    2012-01-01

    Full Text Available Ionic liquids (ILs are salt that exist in the liquid phase at and around 298 K and are comprised of a bulky, asymmetric organic cation and the anion usually inorganic ion but some ILs also with organic anion. ILs have attracted much attention as a replacement for traditional organic solvents as they possess many attractive properties. Among these properties, intrinsic ion conductivity, low volatility, high chemical and thermal stability, low combustibility, and wide electrochemical windows are few. Due to negligible or nonzero volatility of these solvents, they are considered “greener” for the environment as they do not evaporate like volatile organic compounds (VOCs. ILs have been widely used in electrodeposition, electrosynthesis, electrocatalysis, electrochemical capacitor, lubricants, plasticizers, solvent, lithium batteries, solvents to manufacture nanomaterials, extraction, gas absorption agents, and so forth. Besides a brief discussion of the introduction, history, and properties of ILs the major purpose of this review paper is to provide an overview on the advantages of ILs for the synthesis of conducting polymer and nanoparticle when compared to conventional media and also to focus on the electrochemical sensors and biosensors based on IL/composite modified macrodisk electrodes. Subsequently, recent developments and major strategies for enhancing sensing performance are discussed.

  7. Preparation of copper (I) oxide nanohexagon decorated reduced graphene oxide nanocomposite and its application in electrochemical sensing of dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Sivasubramanian, R., E-mail: rss@psgias.ac.in; Biji, P.

    2016-08-15

    Highlights: • Cu{sub 2}O nanohexagon–reduced graphene oxide (rGO) nanocomposite has been prepared by in-situ reduction method. • The rGO-Cu{sub 2}O/GCE exhibited excellent catalytic properties for dopamine due to the synergistic action of the nanocomposite. • The proposed sensor is highly selective toward dopamine in the presence of ascorbic acid and uric acid. - Graphical Abstract: - Abstract: An electrochemical sensor using copper (I) oxide nanostructure decorated reduced graphene oxide (rGO) nanocomposite has been proposed for selective detection of dopamine. The rGO–Cu{sub 2}O nanocomposite was synthesized by in-situ chemical reduction method and was characterized using Transmission Electron Microscope (TEM), Energy Dispersive X-ray (EDX) analysis, X-ray Diffraction (XRD) patterns, Fourier Transform Infrared (FTIR), UV–vis and Raman Spectroscopy, respectively. From Cyclic Voltammetric (CV) studies, it was inferred that rGO–Cu{sub 2}O/GCE exhibits excellent electrocatalytic activity toward dopamine, which is attributed to the enhanced conductivity as well as the synergistic effect of the nanocomposite. The sensing was carried out using Differential Pulse Voltammetry (DPV) wherefrom a Limit of Detection (LOD) of 50 nM with a linear range from 10 µM to 900 µM was estimated. The effect of potential interfering agents such as Uric Acid (UA), Ascorbic Acid (AA), glucose, K{sup +}, Na{sup +}, Cl{sup −}, and SO{sub 4}{sup −} ions toward sensing were investigated. The performance of the sensor toward the estimation of dopamine in human blood and urine samples were analyzed. The facile method for the preparation of a nanocomposite in conjunction with the low detection limit and the wide linear range for dopamine sensing is the advantage of this present study.

  8. All-Carbon Electrode Consisting of Carbon Nanotubes on Graphite Foil for Flexible Electrochemical Applications

    Directory of Open Access Journals (Sweden)

    Je-Hwang Ryu

    2014-03-01

    Full Text Available We demonstrate the fabrication of an all-carbon electrode by plasma-enhanced chemical vapor deposition for use in flexible electrochemical applications. The electrode is composed of vertically aligned carbon nanotubes that are grown directly on a flexible graphite foil. Being all-carbon, the simple fabrication process and the excellent electrochemical characteristics present an approach through which high-performance, highly-stable and cost-effective electrochemical applications can be achieved.

  9. Templated synthesis, characterization, and sensing application of macroscopic platinum nanowire network electrodes

    DEFF Research Database (Denmark)

    Wang, D. H.; Kou, R.; Gil, M. P.

    2005-01-01

    properties of the electrodes, such as electrochemical active area and methanol oxidation, have also been studied. Compared with conventional polycrystalline Pt electrodes, these novel nanowire network electrodes possess high electrochemical active areas and demonstrate higher current densities and a lower...... onset potential for methanol electro-oxidation. Enzymatic Pt nanowire-network-based sensors show higher sensitivity for glucose detection than that using conventional polycrystalline Pt electrode. Such macroscopic nanowire network electrodes provide ideal platforms for sensing and other device......Abstract: Novel platinum nanowire network electrodes have been fabricated through electrodeposition using mesoporous silica thin films as templates. These electrodes were characterized by X-ray diffraction, transmission electron microscope, and scanning electron microscope. The electrochemical...

  10. Ion sensors based on novel fiber organic electrochemical transistors for lead ion detection.

    Science.gov (United States)

    Wang, Yuedan; Zhou, Zhou; Qing, Xing; Zhong, Weibing; Liu, Qiongzhen; Wang, Wenwen; Li, Mufang; Liu, Ke; Wang, Dong

    2016-08-01

    Fiber organic electrochemical transistors (FECTs) based on polypyrrole and nanofibers have been prepared for the first time. FECTs exhibited excellent electrical performances, on/off ratios up to 10(4) and low applied voltages below 2 V. The ion sensitivity behavior of the fiber organic electrochemical transistors was investigated. It exhibited that the transfer curve of FECTs shifted to lower gate voltage with increasing cations concentration, the sensitivity reached to 446 μA/dec in the 10(-5)-10(-2) M Pb(2+) concentration range. The ion selective properties of the FECTs have also been systematically studied for the detection of potassium, calcium, aluminum, and lead ions. The devices with different cations showed great difference in response curves. It was suitable for selectively monitoring Pb(2+) with respect to other cations. The results indicated FECTs were very effective for electrochemical sensing of lead ion, which opened a promising perspective for wearable electronics in healthcare and biological application. Graphical Abstract The schematic diagram of fiber organic electrochemical transistors based on polypyrrole and nanofibers for ion sensing.

  11. Electrochemical Biosensors - Sensor Principles and Architectures

    Science.gov (United States)

    Grieshaber, Dorothee; MacKenzie, Robert; Vörös, Janos; Reimhult, Erik

    2008-01-01

    Quantification of biological or biochemical processes are of utmost importance for medical, biological and biotechnological applications. However, converting the biological information to an easily processed electronic signal is challenging due to the complexity of connecting an electronic device directly to a biological environment. Electrochemical biosensors provide an attractive means to analyze the content of a biological sample due to the direct conversion of a biological event to an electronic signal. Over the past decades several sensing concepts and related devices have been developed. In this review, the most common traditional techniques, such as cyclic voltammetry, chronoamperometry, chronopotentiometry, impedance spectroscopy, and various field-effect transistor based methods are presented along with selected promising novel approaches, such as nanowire or magnetic nanoparticle-based biosensing. Additional measurement techniques, which have been shown useful in combination with electrochemical detection, are also summarized, such as the electrochemical versions of surface plasmon resonance, optical waveguide lightmode spectroscopy, ellipsometry, quartz crystal microbalance, and scanning probe microscopy. The signal transduction and the general performance of electrochemical sensors are often determined by the surface architectures that connect the sensing element to the biological sample at the nanometer scale. The most common surface modification techniques, the various electrochemical transduction mechanisms, and the choice of the recognition receptor molecules all influence the ultimate sensitivity of the sensor. New nanotechnology-based approaches, such as the use of engineered ion-channels in lipid bilayers, the encapsulation of enzymes into vesicles, polymersomes, or polyelectrolyte capsules provide additional possibilities for signal amplification. In particular, this review highlights the importance of the precise control over the delicate

  12. Retrieval operators of remote sensing applications

    International Nuclear Information System (INIS)

    Ahmad, T.; Shah, A.

    2014-01-01

    A set of operators of remote sensing applications have been proposed to fulfill most of the Functional Requirements (FR). These operators capture the functions of the applications, which can be considered as the services provided by the applications. In general, a good application meets maximum FR from user. In this paper, we have defined a remote sensing application by a set, having all images created at dissimilar time instances, and each image is categorized into set of different layers. (author)

  13. Melt quenched vanadium oxide embedded in graphene oxide sheets as composite electrodes for amperometric dopamine sensing and lithium ion battery applications

    Science.gov (United States)

    Sreejesh, M.; Shenoy, Sulakshana; Sridharan, Kishore; Kufian, D.; Arof, A. K.; Nagaraja, H. S.

    2017-07-01

    Electrochemical sensors and lithium-ion batteries are two important topics in electrochemistry that have attracted much attention owing to their extensive applications in enzyme-free biosensors and portable electronic devices. Herein, we report a simple hydrothermal approach for synthesizing composites of melt quenched vanadium oxide embedded on graphene oxide of equal proportion (MVGO50) for the fabrication of electrodes for nonenzymatic amperometic dopamine sensor and lithium-ion battery applications. The sensing performance of MVGO50 electrodes through chronoamperometry studies in 0.1 M PBS solution (at pH 7) over a wide range of dopamine concentration exhibited a highest sensitivity of 25.02 μA mM-1 cm-2 with the lowest detection limit of 0.07 μM. In addition, the selective sensing capability of MVGO50 was also tested through chronoamperometry studies by the addition of a very small concentration of dopamine (10 μM) in the presence of a fairly higher concentration of uric acid (10 mM) as the interfering species. Furthermore, the reversible lithium cycling properties of MVGO50 are evaluated by galvanostatic charge-discharge cycling studies. MVGO50 electrodes exhibited enhanced rate capacity of up to 200 mAhg-1 at a current of 0.1C rate and remained stable during cycling. These results indicate that MVGO composites are potential candidates for electrochemical device applications.

  14. MnWO{sub 4} nanocapsules: Synthesis, characterization and its electrochemical sensing property

    Energy Technology Data Exchange (ETDEWEB)

    Muthamizh, Selvamani; Suresh, Ranganathan; Giribabu, Krishnamoorthy; Manigandan, Ramadoss; Praveen Kumar, Sivakumar; Munusamy, Settu; Narayanan, Vengidusamy, E-mail: vnnara@yahoo.co.in

    2015-01-15

    Highlights: • Synthesis of MnWO{sub 4} nanocapsules without use of any other external reagent. • High crystalline MnWO{sub 4} was obtained with phase purity. • Electrochemical sensing platform based on MnWO{sub 4} for sensing quercetin. • Micromolar detection ability of MnWO{sub 4} modified GCE. - Abstract: Manganese tungstate (MnWO{sub 4}) was synthesized by surfactant free precipitation method. MnWO{sub 4} was characterized by using various spectroscopic techniques. The phase, crystalline nature and the morphological analysis were carried out using XRD, scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HR-TEM). Further, FT-IR, Raman, and DRS-UV–Vis spectral analysis were carried out in order to ascertain the optical property and the presence of functional groups. From the analysis, the morphology of the MnWO{sub 4} was observed to be in capsules with breadth and thickness were in nm range. The oxidation state of tungsten (W), and manganese (Mn) were investigated using X-ray photo electron spectroscopy (XPS) and electron paramagnetic resonance spectroscopy (EPR). The synthesized MnWO{sub 4} nanocapsules were used to modify glassy carbon electrode (GCE) to detect quercetin.

  15. Electroactive monolithic μchip for electrochemically-responsive chromatography

    OpenAIRE

    Power, Aoife

    2013-01-01

    The EMμ project’s focus is ultimately, the development of an electroactive monolith that can be incorporated into a microfluidic system for electroanalytical applications such as sensing and electrochemically-controlled extractions and separations. To date our have made several significant advances to achieving this end goal. Firstly a facile fabrication method which allows for the production of fully disposable, gasket–free thin–layer cells suitable for EMμ was developed. A polydimethylsilox...

  16. Acetaminophen and acetone sensing capabilities of nickel ferrite nanostructures

    Science.gov (United States)

    Mondal, Shrabani; Kumari, Manisha; Madhuri, Rashmi; Sharma, Prashant K.

    2017-07-01

    Present work elucidates the gas sensing and electrochemical sensing capabilities of sol-gel-derived nickel ferrite (NF) nanostructures based on the electrical and electrochemical properties. In current work, the choices of target species (acetone and acetaminophen) are strictly governed by their practical utility and concerning the safety measures. Acetone, the target analyte for gas sensing measurement is a common chemical used in varieties of application as well as provides an indirect way to monitor diabetes. The gas sensing experiments were performed within a homemade sensing chamber designed by our group. Acetone gas sensor (NF pellet sensor) response was monitored by tracking the change in resistance both in the presence and absence of acetone. At optimum operating temperature 300 °C, NF pellet sensor exhibits selective response for acetone in the presence of other common interfering gases like ethanol, benzene, and toluene. The electrochemical sensor fabricated to determine acetaminophen is prepared by coating NF onto the surface of pre-treated/cleaned pencil graphite electrode (NF-PGE). The common name of target analyte acetaminophen is paracetamol (PC), which is widespread worldwide as a well-known pain killer. Overdose of PC can cause renal failure even fatal diseases in children and demand accurate monitoring. Under optimal conditions NF-PGE shows a detection limit as low as 0.106 μM with selective detection ability towards acetaminophen in the presence of ascorbic acid (AA), which co-exists in our body. Use of cheap and abundant PGE instead of other electrodes (gold/Pt/glassy carbon electrode) can effectively reduce the cost barrier of such sensors. The obtained results elucidate an ample appeal of NF-sensors in real analytical applications viz. in environmental monitoring, pharmaceutical industry, drug detection, and health monitoring.

  17. Electrochemically Active Biofilms Assisted Nanomaterial Synthesis for Environmental Applications

    KAUST Repository

    Ahmed, Elaf

    2017-01-01

    Nanomaterials have a great potential for environmental applications due to their high surface areas and high reactivity. This dissertation investigated the use of electrochemically active biofilms (EABs) as a synthesis approach for the fabrication

  18. Chip cleaning and regeneration for electrochemical sensor arrays

    Energy Technology Data Exchange (ETDEWEB)

    Bhalla, Vijayender [Biochemistry Department ' G.Moruzzi' , University of Bologna, Via Irnerio 48, 40126 Bologna (Italy); Carrara, Sandro, E-mail: sandro.carrara@epfl.c [Biochemistry Department ' G.Moruzzi' , University of Bologna, Via Irnerio 48, 40126 Bologna (Italy); Stagni, Claudio [Department DEIS, University of Bologna, viale Risorgimento 2, 40136 Bologna (Italy); Samori, Bruno [Biochemistry Department ' G.Moruzzi' , University of Bologna, Via Irnerio 48, 40126 Bologna (Italy)

    2010-04-02

    Sensing systems based on electrochemical detection have generated great interest because electronic readout may replace conventional optical readout in microarray. Moreover, they offer the possibility to avoid labelling for target molecules. A typical electrochemical array consists of many sensing sites. An ideal micro-fabricated sensor-chip should have the same measured values for all the equivalent sensing sites (or spots). To achieve high reliability in electrochemical measurements, high quality in functionalization of the electrodes surface is essential. Molecular probes are often immobilized by using alkanethiols onto gold electrodes. Applying effective cleaning methods on the chip is a fundamental requirement for the formation of densely-packed and stable self-assembly monolayers. However, the available well-known techniques for chip cleaning may not be so reliable. Furthermore, it could be necessary to recycle the chip for reuse. Also in this case, an effective recycling technique is required to re-obtain well cleaned sensing surfaces on the chip. This paper presents experimental results on the efficacy and efficiency of the available techniques for initial cleaning and further recycling of micro-fabricated chips. Piranha, plasma, reductive and oxidative cleaning methods were applied and the obtained results were critically compared. Some interesting results were attained by using commonly considered cleaning methodologies. This study outlines oxidative electrochemical cleaning and recycling as the more efficient cleaning procedure for electrochemical based sensor arrays.

  19. Self-Assembled Nanorod Structures on Nanofibers for Textile Electrochemical Capacitor Electrodes with Intrinsic Tactile Sensing Capabilities.

    Science.gov (United States)

    Shi, HaoTian H; Khalili, Nazanin; Morrison, Taylor; Naguib, Hani E

    2018-05-21

    A novel polyaniline nanorod (PAniNR) three-dimensional structure was successfully grown on flexible polyacrylonitrile (PAN) nanofiber substrate as the electrode material for electrochemical capacitors (ECs), constructed via self-stabilized dispersion polymerization process. The electrode offered desired mechanical properties such as flexibility and bendability, whereas it maintained optimal electrochemical characteristics. The electrode and the assembled EC cell also achieved intrinsic piezoresistive sensing properties, leading to real-time monitoring of excess mechanical pressure and bending during cell operations. The PAniNR@PAN electrodes show an average diameter of 173.6 nm, with the PAniNR growth of 50.7 nm in length. Compared to the electrodes made from pristine PAni, the gravimetric capacitance increased by 39.8% to 629.6 F/g with aqueous acidic electrolyte. The electrode and the assembled EC cell with gel electrolyte were responsive to tensile, compressive, and bending stresses with a sensitivity of 0.95 MPa -1 .

  20. Electrochemical sensing behaviour of Ni doped Fe{sub 3}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Suresh, R.; Giribabu, K.; Manigandan, R.; Narayanan, V., E-mail: vnnara@yahoo.co.in [Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai 600 025 (India); Vijayalakshmi, L. [Annai Veilankanni' s College for Women (Arts and Science), Saidapet, Chennai 600015 (India); Stephen, A. [Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600 025 (India)

    2014-01-28

    Ni doped Fe{sub 3}O{sub 4} nanoparticles were synthesized by simple hydrothermal method. The prepared nanomaterials were characterized by X-ray diffraction analysis, DRS-UV-Visible spectroscopy and field emission scanning electron microscopy. The XRD confirms the phase purity of the synthesized Ni doped Fe{sub 3}O{sub 4} nanoparticles. The optical property of Ni doped Fe{sub 3}O{sub 4} nanoparticles were studied by DRS UV-Visible analysis. The electrochemical sensing property of pure and Ni doped Fe{sub 3}O{sub 4} nanoparticles were examined using uric acid as an analyte. The obtained results indicated that the Ni doped Fe{sub 3}O{sub 4} nanoparticles exhibited higher electrocatalytic activity towards uric acid.

  1. Graphene Ink Film Based Electrochemical Detector for Paracetamol Analysis

    Directory of Open Access Journals (Sweden)

    Li Fu

    2018-01-01

    Full Text Available Graphene ink is a commercialized product in the graphene industry with promising potential application in electronic device design. However, the limitation of the graphene ink is its low electronic performance due to the ink preparation protocol. In this work, we proposed a simple post-treatment of graphene ink coating via electrochemical oxidation. The electronic conductivity of the graphene ink coating was enhanced as expected after the treatment. The proposed electrochemical oxidation treatment also exposes the defects of graphene and triggered an electrocatalytic reaction during the sensing of paracetamol (PA. The overpotential of redox is much lower than conventional PA redox potential, which is favorable for avoiding the interference species. Under optimum conditions, the graphene ink-based electrochemical sensor could linearly detect PA from 10 to 500 micro molar (μM, with a limit of detection of 2.7 μM.

  2. LPG and NH3 sensing characteristics of DC electrochemically deposited Co3O4 films

    Science.gov (United States)

    Shelke, P. N.; Khollam, Y. B.; Gunjal, S. D.; Koinkar, P. M.; Jadkar, S. R.; Mohite, K. C.

    2015-03-01

    Present communication reports the LPG and NH3 sensing properties of Co3O4 films prepared on throughly cleaned stainless steel (SS) and copper (CU) substrates by using DC electrochemical deposition method followed by air annealing at 350°C/2 h. The resultant films are characterized by using X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The LPG and NH3 gas sensing properties of these films are measured at room temperature (RT) by using static gas sensing system at different concentrations of test gas ranging from 25 ppm to 350 ppm. The XRD and Raman spectroscopy studies clearly indicated the formation of pure cubic spinel Co3O4 in all films. The LPG and NH3 gas sensing properties of films showed (i) the increase in sensitivity factor (S.F.) with gas concentrations and (ii) more sensibility to LPG as compared to NH3 gas. In case of NH3 gas (conc. 150 ppm) and LPG gas (conc. 60 ppm) sensing, the maximum S.F. = 270 and 258 are found for the films deposited on CU substrates, respectively. For all films, the response time (3-5 min.) is found to be much higher than the recovery time (30-50 sec). For all films, the response and recovery time are found to be higher for LPG as compared to NH3 gas. Further, repeatability-reproducibility in gas sensing properties is clearly noted by analysis of data for number of cycles recorded for all films from different set of depositions.

  3. New advance in the research of post-remote sensing application technology. Series of 'proposition and consideration of post-remote sensing application technology'

    International Nuclear Information System (INIS)

    Liu Dechang; Ye Fawang

    2005-01-01

    Based on deep consideration in post-remote sensing application technology, this article pays more attention to its technological meaning. The application idea of post-remote sensing application technology to uranium exploration is also discussed. The proposition and research on new concept of post-remote sensing application technology is an important search and of important theoretical and practical significance to uranium exploration. (authors)

  4. Microfabricated Electrochemical Cell-Based Biosensors for Analysis of Living Cells In Vitro

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2012-04-01

    Full Text Available Cellular biochemical parameters can be used to reveal the physiological and functional information of various cells. Due to demonstrated high accuracy and non-invasiveness, electrochemical detection methods have been used for cell-based investigation. When combined with improved biosensor design and advanced measurement systems, the on-line biochemical analysis of living cells in vitro has been applied for biological mechanism study, drug screening and even environmental monitoring. In recent decades, new types of miniaturized electrochemical biosensor are emerging with the development of microfabrication technology. This review aims to give an overview of the microfabricated electrochemical cell-based biosensors, such as microelectrode arrays (MEA, the electric cell-substrate impedance sensing (ECIS technique, and the light addressable potentiometric sensor (LAPS. The details in their working principles, measurement systems, and applications in cell monitoring are covered. Driven by the need for high throughput and multi-parameter detection proposed by biomedicine, the development trends of electrochemical cell-based biosensors are also introduced, including newly developed integrated biosensors, and the application of nanotechnology and microfluidic technology.

  5. Metal nanostructures for non-enzymatic glucose sensing

    International Nuclear Information System (INIS)

    Tee, Si Yin; Teng, Choon Peng; Ye, Enyi

    2017-01-01

    This review covers the recent development of metal nanostructures in electrochemical non-enzymatic glucose sensing. It highlights a variety of nanostructured materials including noble metals, other transition metals, bimetallic systems, and their hybrid with carbon-based nanomaterials. Particularly, attention is devoted to numerous approaches that have been implemented for improving the sensors performance by tailoring size, shape, composition, effective surface area, adsorption capability and electron-transfer properties. The correlation of the metal nanostructures to the glucose sensing performance is addressed with respect to the linear concentration range, sensitivity and detection limit. In overall, this review provides important clues from the recent scientific achievements of glucose sensor nanomaterials which will be essentially useful in designing better and more effective electrocatalysts for future electrochemical sensing industry. - Highlights: • Overview of recent development of metal nanostructures in electrochemical non-enzymatic glucose sensing. • Special attention is focussed on noble metals, other transition metals, bimetallic systems, and their hybrid with carbon-based nanomaterials. • Merits and limitations of various metal nanostructures in electrochemical non-enzymatic glucose sensing. • Strategies to improve the glucose sensing performance of metal nanostructures as electrocatalysts.

  6. Current status of environmental, health, and safety issues of electrochemical capacitors for advanced vehicle applications

    Energy Technology Data Exchange (ETDEWEB)

    Vimmerstedt, L J; Hammel, C J

    1997-04-01

    Electrochemical capacitors are a candidate for traction power assists in hybrid electric vehicles (HEVs). Other advanced automotive applications, while not the primary focus of current development efforts, are also possible. These include load leveling high-energy batteries, power conditioning electronics, electrically hated catalysts, electric power steering, and engine starter power. Higher power and longer cycle life are expected for electrochemical capacitors than for batteries. Evaluation of environmental, health, and safety (EH and S) issues of electrochemical capacitors is an essential part of the development and commercialization of electrochemical capacitors for advanced vehicles. This report provides an initial EH and S assessment. This report presents electrochemical capacitor electrochemistry, materials selection, intrinsic material hazards, mitigation of those hazards, environmental requirements, pollution control options, and shipping requirements. Most of the information available for this assessment pertains to commercial devices intended for application outside the advanced vehicle market and to experiment or prototype devices. Electrochemical capacitors for power assists in HEVs are not produced commercially now. Therefore, materials for advanced vehicle electrochemical capacitors may change, and so would the corresponding EH and S issues. Although changes are possible, this report describes issues for likely electrochemical capacitor designs.

  7. Nanometric MgFe2O4: Synthesis, characterization and its application towards supercapacitor and electrochemical uric acid sensor

    Science.gov (United States)

    Majumder, S.; Kumar, S.; Banerjee, S.

    2017-05-01

    In this paper, we have synthesized nanocrystalline MgFe2O4 (S1) by auto-combustion assisted sol-gel method. The structure and morphology and elemental study of S1 are examined by powder X-ray diffraction (PXRD), field emission scanning electron microscopic (FESEM) and energy dispersive X-ray spectroscopic (EDS) techniques. The FESEM images reveal that the morphology of the sample is rough and average particle size is 50 nm. The PXRD study indicates that the samples are well crystalline and single phase in nature. Moreover, we have performed supercapacitor study by electrochemical galvanostatic charge-discharge (GCD) measurement, which shows pseudo capacitive behavior. S1 contains a high specific capacitance of 428.9 Fg-1 at the current density 0.0625 Ag-1 and can deliver high energy and power density of 18.01 Wh kg-1 and 21468 Wkg-1 respectively. Moreover, uric acid (UA) sensing study has also been performed by cyclic voltmetry (CV) and electrochemical impedance spectroscopy measurement (EIS) of S1. We can use nanocrystalline MgFe2O4 as supercapacitor and UA sensor applications purpose.

  8. Polypyrrol/chitosan hydrogel hybrid microfiber as sensing artificial muscle

    Science.gov (United States)

    Ismail, Yahya A.; Martínez, Jose G.; Al Harrasi, Ahmad S.; Kim, Seon J.; Fernández Otero, Toribio F.

    2011-04-01

    An electrochemical actuator demands that it should act as a sensor of the working conditions for its efficient application in devices. Actuation and sensing characteristics of a biopolymer/conducting polymer hybrid microfiber artificial muscle fabricated through wet spinning of a chitosan solution followed by in situ chemical polymerization with pyrrol employing bis(triflouro methane sulfonyl) imide as dopant and ferric chloride as a catalyst is presented. The polypyrrol/chitosan hybrid microfiber was investigated by FTIR, scanning electron microscopy (SEM), electrical conductivity measurement, cyclic voltammetric and chronopotentiometric methods. The electrochemical measurements related to the sensing abilities were performed as a function of applied current, concentration and temperature keeping two of the variables constant at a given time using NaCl as electrolyte. Cyclic voltammograms confirmed that the electro activity is imparted by polypyrrol (pPy). The fiber showed an electrical conductivity of 3.21x10-1 Scm-1and an average linear electrochemical actuation strain of 0.54%. The chronopotentiometric responses during the oxidation/reduction processes of the microfiber for the different anodic/cathodic currents and the linear fit observed for the consumed electrical energy during the reaction for various applied currents suggested that it can act as a sensor of applied current. The chronopotentiometric responses and the linear fit of consumed electrical energy at different temperatures suggested that the actuator can act as a temperature sensor. Similarly a semi logarithmic dependence of the consumed electrical energy with concentration of the electrolyte during reaction is suggestive of its applicability as a concentration sensor. The demand that an electrochemical actuator to be a sensor of the working conditions, for its efficient application in devices is thus verified in this material.

  9. Optical Sensing with Simultaneous Electrochemical Control in Metal Nanowire Arrays

    Directory of Open Access Journals (Sweden)

    Janos Vörös

    2010-11-01

    Full Text Available This work explores the alternative use of noble metal nanowire systems in large-scale array configurations to exploit both the nanowires’ conductive nature and localized surface plasmon resonance (LSPR. The first known nanowire-based system has been constructed, with which optical signals are influenced by the simultaneous application of electrochemical potentials. Optical characterization of nanowire arrays was performed by measuring the bulk refractive index sensitivity and the limit of detection. The formation of an electrical double layer was controlled in NaCl solutions to study the effect of local refractive index changes on the spectral response. Resonance peak shifts of over 4 nm, a bulk refractive index sensitivity up to 115 nm/RIU and a limit of detection as low as 4.5 × 10−4 RIU were obtained for gold nanowire arrays. Simulations with the Multiple Multipole Program (MMP confirm such bulk refractive index sensitivities. Initial experiments demonstrated successful optical biosensing using a novel form of particle-based nanowire arrays. In addition, the formation of an ionic layer (Stern-layer upon applying an electrochemical potential was also monitored by the shift of the plasmon resonance.

  10. Electrochemical impedance spectroscopy versus cyclic voltammetry for the electroanalytical sensing of capsaicin utilising screen printed carbon nanotube electrodes.

    Science.gov (United States)

    Randviir, Edward P; Metters, Jonathan P; Stainton, John; Banks, Craig E

    2013-05-21

    Screen printed carbon nanotube electrodes (SPEs) are explored as electroanalytical sensing platforms for the detection of capsaicin in both synthetic capsaicin solutions and capsaicin extracted from chillies and chilli sauces utilising both cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is found that the technique which is most applicable to the electroanalytical detection of capsaicin depends upon the analyte concentration: for the case of low capsaicin concentrations, CV is a more appropriate method as capsaicin exhibits characteristic voltammetric waves of peak heights relevant to the capsaicin concentration; but for the case of high capsaicin concentrations where the voltammetric waves merge and migrate out of the potential window, EIS is shown to be a more appropriate technique, owing to the observed linear increases in R(ct) with increasing concentration. Furthermore, we explore different types of screen printed carbon nanotube electrodes, namely single- and multi- walled carbon nanotubes, finding that they are technique-specific: for the case of low capsaicin concentrations, single-walled carbon nanotube SPEs are preferable (SW-SPE); yet for the case of EIS at high capsaicin concentrations, multi-walled carbon nanotube SPEs (MW-SPE) are preferred, based upon analytical responses. The analytical performance of CV and EIS is applied to the sensing of capsaicin in grown chillies and chilli sauces and is critically compared to 'gold standard' HPLC analysis.

  11. A Review on the Electrochemical Sensors and Biosensors Composed of Nanowires as Sensing Material

    Directory of Open Access Journals (Sweden)

    Shen-Ming Chen

    2008-01-01

    Full Text Available The development and application of nanowires for electrochemical sensors and biosensors are reviewed in this article. Next generation sensor platforms will require significant improvements in sensitivity, specificity and parallelism in order to meet the future needs in variety of fields. Sensors made of nanowires exploit some fundamental nanoscopic effect in order to meet these requirements. Nanowires are new materials, which have the characteristic of low weight with extraordinary mechanical, electrical, thermal and multifunctional properties. The advantages such as size scale, aspect ratio and other properties of nanowires are especially apparent in the use of electrical sensors such as electrochemical sensors and in the use of field-effect transistors. The preparation methods of nanowires and their properties are discussed along with their advantages towards electrochemical sensors and biosensors. Some key results from each article are summarized, relating the concept and mechanism behind each sensor, with experimental conditions as well as their behavior at different conditions.

  12. Dual sensing-actuation artificial muscle based on polypyrrole-carbon nanotube composite

    Science.gov (United States)

    Schumacher, J.; Otero, Toribio F.; Pascual, Victor H.

    2017-04-01

    Dual sensing artificial muscles based on conducting polymer are faradaic motors driven by electrochemical reactions, which announce the development of proprioceptive devices. The applicability of different composites has been investigated with the aim to improve the performance. Addition of carbon nanotubes may reduce irreversible reactions. We present the testing of a dual sensing artificial muscle based on a conducting polymer and carbon nanotubes composite. Large bending motions (up to 127 degrees) in aqueous solution and simultaneously sensing abilities of the operation conditions are recorded. The sensing and actuation equations are derived for incorporation into a control system.

  13. Nitrogen-doped multiple graphene aerogel/gold nanostar as the electrochemical sensing platform for ultrasensitive detection of circulating free DNA in human serum.

    Science.gov (United States)

    Ruiyi, Li; Ling, Liu; Hongxia, Bei; Zaijun, Li

    2016-05-15

    Graphene aerogel has attracted increasing attention due to its large specific surface area, high-conductivity and electronic interaction. The paper reported a facile synthesis of nitrogen-doped multiple graphene aerogel/gold nanostar (termed as N-doped MGA/GNS) and its use as the electrochemical sensing platform for detection of double stranded (dsDNA). On the one hand, the N-doped MGA offers a much better electrochemical performance compared with classical graphene aerogel. Interestingly, the performance can be enhanced by only increasing the cycle number of graphene oxide gelation. On the other hand, the hybridization with GNS further enhances the electrocatalytic activity towards Fe(CN)6(3-/4-). In addition, the N-doped MGA/GNS provides a well-defined three-dimensional architecture. The unique structure make it is easy to combine with dsDNA to form the electroactive bioconjugate. The integration not only triggers an ultrafast DNA electron and charge transfer, but also realizes a significant synergy between N-doped MGA, GNS and dsDNA. As a result, the electrochemical sensor based on the hybrid exhibits highly sensitive differential pulse voltammetric response (DPV) towards dsDNA. The DPV signal linearly increases with the increase of dsDNA concentration in the range from 1.0×10(-)(21) g ml(-)(1) to 1.0×10(-16) g ml(-1) with the detection limit of 3.9×10(-22) g ml(-1) (S/N=3). The sensitivity is much more than that of all reported DNA sensors. The analytical method was successfully applied in the electrochemical detection of circulating free DNA in human serum. The study also opens a window on the electrical properties of multiple graphene aerogel and DNA as well their hybrids to meet the needs of further applications as special nanoelectronics in molecule diagnosis, bioanalysis and catalysis. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Evaluation of gas-sensing properties of ZnO nanostructures electrochemically doped with Au nanophases

    Directory of Open Access Journals (Sweden)

    Elena Dilonardo

    2016-01-01

    Full Text Available A one-step electrochemical method based on sacrificial anode electrolysis (SAE was used to deposit stabilized gold nanoparticles (Au NPs directly on the surface of nanostructured ZnO powders, previously synthesized through a sol–gel process. The effect of thermal annealing temperatures (300 and 550 °C on chemical, morphological, and structural properties of pristine and Au-doped ZnO nancomposites (Au@ZnO was investigated. Transmission and scanning electron microscopy (TEM and SEM, as well as X-ray photoelectron spectroscopy (XPS, revealed the successful deposition of nanoscale gold on the surface of spherical and rod-like ZnO nanostructures, obtained after annealing at 300 and 550 °C, respectively. The pristine ZnO and Au@ZnO nanocomposites are proposed as active layer in chemiresistive gas sensors for low-cost processing. Gas-sensing measurements towards NO2 were collected at 300 °C, evaluating not only the Au-doping effect, but also the influence of the different ZnO nanostructures on the gas-sensing properties.

  15. Facile synthesis of the necklace-like graphene oxide-multi-walled carbon nanotube nanohybrid and its application in electrochemical sensing of Azithromycin

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kaixin [Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Lu, Limin; Wen, Yangping [Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); College of Science, Jiangxi Agricultural University, Nanchang 330045 (China); Xu, Jingkun, E-mail: xujingkun@tsinghua.org.cn [Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Duan, Xuemin; Zhang, Long; Hu, Dufen [Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Nie, Tao [Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); College of Science, Jiangxi Agricultural University, Nanchang 330045 (China)

    2013-07-17

    Graphical abstract: -- Highlights: •The necklace-like GO-MWCNTs nanohybrid was facilely synthesized by ultrasonication. •The nanocomposites can be effectively used for the detection of Azithromycin. •Low detection limit with wide linear range could be obtained. •The method was applied to determine Azi in real samples. -- Abstract: A novel electrochemical platform was designed for the determination of Azithromycin (Azi), a widely used macrolide antibiotic, by combining the hydrophilic properties of graphene oxide (GO) and the excellent electronic and antifouling properties of multi-walled carbon nanotubes (MWCNTs). Stable MWCNTs aqueous dispersion has been prepared using GO nano-sheets as surfactant and the obtained GO-MWCNTs nanohybrid was characterized by UV–vis spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy and electrochemical impedance spectroscopy, which confirmed that GO nano-sheets were attached onto the wall of MWCNTs to form a necklace-like structure. Electrochemical results obviously reveal that the oxidation peak currents of Azi obtained at the GC electrode modified with GO-MWCNTs hybrid are much higher than those at the MWCNTs/GC, GO/GC and bare GC electrodes. Under optimized conditions, the anodic peak current was linear to the concentration of Azi in the range from 0.1 to 10 μM with the detection limit of 0.07 μM. To further validate its possible application, the proposed method was successfully used for the determination of Azi in pharmaceutical formulations with satisfactory results.

  16. Facile synthesis of the necklace-like graphene oxide-multi-walled carbon nanotube nanohybrid and its application in electrochemical sensing of Azithromycin

    International Nuclear Information System (INIS)

    Zhang, Kaixin; Lu, Limin; Wen, Yangping; Xu, Jingkun; Duan, Xuemin; Zhang, Long; Hu, Dufen; Nie, Tao

    2013-01-01

    Graphical abstract: -- Highlights: •The necklace-like GO-MWCNTs nanohybrid was facilely synthesized by ultrasonication. •The nanocomposites can be effectively used for the detection of Azithromycin. •Low detection limit with wide linear range could be obtained. •The method was applied to determine Azi in real samples. -- Abstract: A novel electrochemical platform was designed for the determination of Azithromycin (Azi), a widely used macrolide antibiotic, by combining the hydrophilic properties of graphene oxide (GO) and the excellent electronic and antifouling properties of multi-walled carbon nanotubes (MWCNTs). Stable MWCNTs aqueous dispersion has been prepared using GO nano-sheets as surfactant and the obtained GO-MWCNTs nanohybrid was characterized by UV–vis spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy and electrochemical impedance spectroscopy, which confirmed that GO nano-sheets were attached onto the wall of MWCNTs to form a necklace-like structure. Electrochemical results obviously reveal that the oxidation peak currents of Azi obtained at the GC electrode modified with GO-MWCNTs hybrid are much higher than those at the MWCNTs/GC, GO/GC and bare GC electrodes. Under optimized conditions, the anodic peak current was linear to the concentration of Azi in the range from 0.1 to 10 μM with the detection limit of 0.07 μM. To further validate its possible application, the proposed method was successfully used for the determination of Azi in pharmaceutical formulations with satisfactory results

  17. Study on Electrochemical Insulin Sensing Utilizing a DNA Aptamer-Immobilized Gold Electrode

    Directory of Open Access Journals (Sweden)

    Izumi Kubo

    2015-07-01

    Full Text Available We investigated an insulin-sensing method by utilizing an insulin-binding aptamer IGA3, which forms an anti-parallel G-quadruplex with folded single strands. Spectroscopic observation indicates that some anti-parallel G-quadruplex bind hemin and show peroxidase activity. In this study, the peroxidase activity of IGA3 with hemin was confirmed by spectrophotometric measurements, i.e., the activity was three-times higher than hemin itself. IGA3 was then immobilized onto a gold electrode to determine its electrochemical activity. The peroxidase activity of the immobilized IGA3-hemin complex was determined by cyclic voltammetry, and a cathodic peak current of the electrode showed a dependence on the concentration of H2O2. The cathodic peak current of the IGA3-hemin complex decreased by binding it to insulin, and this decrease depended on the concentration of insulin.

  18. Electrochemical sensors and biosensors based on redox polymer/carbon nanotube modified electrodes: a review.

    Science.gov (United States)

    Barsan, Madalina M; Ghica, M Emilia; Brett, Christopher M A

    2015-06-30

    The aim of this review is to present the contributions to the development of electrochemical sensors and biosensors based on polyphenazine or polytriphenylmethane redox polymers together with carbon nanotubes (CNT) during recent years. Phenazine polymers have been widely used in analytical applications due to their inherent charge transport properties and electrocatalytic effects. At the same time, since the first report on a CNT-based sensor, their application in the electroanalytical chemistry field has demonstrated that the unique structure and properties of CNT are ideal for the design of electrochemical (bio)sensors. We describe here that the specific combination of phenazine/triphenylmethane polymers with CNT leads to an improved performance of the resulting sensing devices, because of their complementary electrical, electrochemical and mechanical properties, and also due to synergistic effects. The preparation of polymer/CNT modified electrodes will be presented together with their electrochemical and surface characterization, with emphasis on the contribution of each component on the overall properties of the modified electrodes. Their importance in analytical chemistry is demonstrated by the numerous applications based on polymer/CNT-driven electrocatalytic effects, and their analytical performance as (bio) sensors is discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Preparation and Characterization of a PEDOT-Manganese Oxide Composite, and Its Application to Electrochemical Sensing

    International Nuclear Information System (INIS)

    Arena, A.

    2016-01-01

    Stable and transparent aqueous dispersions of a hybrid organic-inorganic composite, are prepared by electrochemically doping Manganese Oxide into Polyethylendioxythiophene (PEDOT). Films deposited from the PEDOT-MnOx dispersions, are characterized by means of electrical and optical measurements, and by means of Atomic Force Microscopy (AFM) investigations. The PEDOT-MnOx composite is then used to modify one of the gold electrodes of a simple electrochemical cell, in which Nafion is used as a solid electrolyte. The cell is characterized using time domain electrical measurements. It is found that distinguishable redox peaks arise in the current-voltage loops of the cell, as nanomolar amounts of either acetic acid and ammonia, are added to the deionized water into which the cell is immersed. The intensity of such current peaks, is linearly related to the concentration of the analytes, in the nanomolar range of concentrations. (paper)

  20. Synthesis of graphene nanomaterials and their application in electrochemical energy storage

    Science.gov (United States)

    Xiong, Guoping

    The need to store and use energy on diverse scales in a modern technological society necessitates the design of large and small energy systems, among which electrical energy storage systems such as batteries and capacitors have attracted much interest in the past several decades. Supercapacitors, also known as ultracapacitors, or electrochemical capacitors, with fast power delivery and long cycle life are complementing or even replacing batteries in many applications. The rapid development of miniaturized electronic devices has led to a growing need for rechargeable micro-power sources with high performance. Among different sources, electrochemical micro-capacitors or micro-supercapacitors provide higher power density than their counterparts and are gaining increased interest from the research and engineering communities. Rechargeable Li ion batteries with high energy and power density, long cycling life, high charge-discharge rate (1C - 3C) and safe operation are in high demand as power sources and power backup for hybrid electric vehicles and other applications. In the present work, graphene-based graphene materials have been designed and synthesized for electrochemical energy storage applications, e.g., conventional supercapacitors (macro-supercapacitors), microsupercapacitors and lithium ion batteries. Factors influencing the formation and structure of graphitic petals grown by microwave plasma-enhanced chemical vapor deposition on oxidized silicon substrates were investigated through process variation and materials analysis. Insights gained into the growth mechanism of these graphitic petals suggest a simple scribing method can be used to control both the location and formation of petals on flat Si substrates. Transitional metal oxides and conducting polymers have been coated on the graphitic petal-based electrodes by facile chemical methods for multifunctional energy storage applications. Detailed electrochemical characterization (e.g., cyclic voltammetry and

  1. Recent advances in transition-metal dichalcogenides based electrochemical biosensors: A review.

    Science.gov (United States)

    Wang, Yi-Han; Huang, Ke-Jing; Wu, Xu

    2017-11-15

    Layered transition metal dichalcogenides (TMDCs) comprise a category of two-dimensional (2D) materials that offer exciting properties, including large surface area, metallic and semi-conducting electrical capabilities, and intercalatable morphologies. Biosensors employ biological molecules to recognize the target and utilize output elements which can translate the biorecognition event into electrical, optical or mass-sensitive signals to determine the quantities of the target. TMDCs nanomaterials have been widely applied in various electrochemical biosensors with high sensitivity and selectivity. The marriage of TMDCs and electrochemical biosensors has created many productive sensing strategies for applications in the areas of clinical diagnosis, environmental monitoring and food safety. In recent years, an increasing number of TMDCs-based electrochemical biosensors are reported, suggesting TMDCs offers new possibilities of improving the performance of electrochemical biosensors. This review summarizes recent advances in electrochemical biosensors based on TMDCs for detection of various inorganic and organic analytes in the last five years, including glucose, proteins, DNA, heavy metal, etc. In addition, we also point out the challenges and future perspectives related to the material design and development of TMDCs-based electrochemical biosensors. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Sensing molecular properties by ATR-SPP Raman spectroscopy on electrochemically structured sensor chips

    International Nuclear Information System (INIS)

    Zerulla, D.; Isfort, G.; Koelbach, M.; Otto, A.; Schierbaum, K.

    2003-01-01

    The use of electrochemically structured Al surfaces as sensor arrays for combinatorial chemistry and its detection via microscopic laser techniques from very small volumes has been explored. The methodology is based on three different techniques which will be discussed separately: firstly, attenuated total reflection (ATR) is used in connection with surface-plasmon-polariton (SPP) excitation. A thin Al layer, evaporated on sapphire or quartz and covered with a naturally grown oxide layer, provides an optimum enhancement and confinement of the electrical field close to the surface. This is revealed by calculations and experimental data. Secondly, a Raman microscope is applied, enabling chemical spot analysis in the visible and UV range with a lateral resolution close to the diffraction limit. Finally, its application to investigate electrochemically structured Al films is discussed

  3. Developing status of satellite remote sensing and its application

    International Nuclear Information System (INIS)

    Zhang Wanliang; Liu Dechang

    2005-01-01

    This paper has discussed the latest development of satellite remote sensing in sensor resolutions, satellite motion models, load forms, data processing and its application. The authors consider that sensor resolutions of satellite remote sensing have increased largely. Valid integration of multisensors is a new idea and technology of satellite remote sensing in the 21st century, and post-remote sensing application technology is the important part of deeply applying remote sensing information and has great practical significance. (authors)

  4. Application of electrochemical optical waveguide lightmode spectroscopy for studying the effect of different stress factors on lactic acid bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Adanyi, Nora [Central Food Research Institute, H-1537 Budapest, P.O. Box 393 (Hungary)]. E-mail: n.adanyi@cfri.hu; Nemeth, Edina [Central Food Research Institute, H-1537 Budapest, P.O. Box 393 (Hungary); Halasz, Anna [Central Food Research Institute, H-1537 Budapest, P.O. Box 393 (Hungary); Szendro, Istvan [MicroVacuum Ltd., H-1147 Budapest, Kerekgyarto u. 10 (Hungary); Varadi, Maria [Central Food Research Institute, H-1537 Budapest, P.O. Box 393 (Hungary)

    2006-07-28

    Electrochemical optical waveguide lightmode spectroscopy (EC-OWLS) has been developed to combine evanescent-field optical sensing with electrochemical control of surface adsorption processes. For bioanalytical sensing, a layer of indium tin oxide (ITO) served as both a high-refractive index waveguide and a conductive electrode. In addition, an electrochemical flow-through fluid cuvette was applied, which incorporated working, reference, and counter electrodes, and was compatible with the constraints of optical sensing. The subject of our study was to monitor how the different stress factors (lactic acid, acetic acid and hydrogen peroxide) influence the survival of lactic acid bacteria. The advantage of EC-OWLS technique is that we could carry out kinetic studies on the behaviour of bacteria under stress conditions, and after exposure of lactobacilli to acid and oxidative stress we get faster results about the status of bacteria compared to the traditional quantitative methods. After optimization of the polarization potential used, calibration curve was determined and the sensor response of different rate of living and damaged cells was studied. The bacterial cells were adsorbed in native form on the surface of the sensor by ensuring polarizing potential (1 V) and were exposed to different concentration of acetic acid and hydrogen peroxide solution to 1 h, respectively and the behaviour of bacteria was monitored. Results were compared to traditional micro-assay method.

  5. Application of electrochemical optical waveguide lightmode spectroscopy for studying the effect of different stress factors on lactic acid bacteria

    International Nuclear Information System (INIS)

    Adanyi, Nora; Nemeth, Edina; Halasz, Anna; Szendro, Istvan; Varadi, Maria

    2006-01-01

    Electrochemical optical waveguide lightmode spectroscopy (EC-OWLS) has been developed to combine evanescent-field optical sensing with electrochemical control of surface adsorption processes. For bioanalytical sensing, a layer of indium tin oxide (ITO) served as both a high-refractive index waveguide and a conductive electrode. In addition, an electrochemical flow-through fluid cuvette was applied, which incorporated working, reference, and counter electrodes, and was compatible with the constraints of optical sensing. The subject of our study was to monitor how the different stress factors (lactic acid, acetic acid and hydrogen peroxide) influence the survival of lactic acid bacteria. The advantage of EC-OWLS technique is that we could carry out kinetic studies on the behaviour of bacteria under stress conditions, and after exposure of lactobacilli to acid and oxidative stress we get faster results about the status of bacteria compared to the traditional quantitative methods. After optimization of the polarization potential used, calibration curve was determined and the sensor response of different rate of living and damaged cells was studied. The bacterial cells were adsorbed in native form on the surface of the sensor by ensuring polarizing potential (1 V) and were exposed to different concentration of acetic acid and hydrogen peroxide solution to 1 h, respectively and the behaviour of bacteria was monitored. Results were compared to traditional micro-assay method

  6. Facile fabrication of nanoporous PdFe alloy for nonenzymatic electrochemical sensing of hydrogen peroxide and glucose

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jinping [Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Wang, Zhihong [School of Basic Medical Sciences, Shandong University of Traditional Chinese Medicine, Jinan 250355 (China); Zhao, Dianyun [Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Xu, Caixia, E-mail: chm_xucx@ujn.edu.cn [Key Laboratory of Chemical Sensing and Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China)

    2014-06-01

    Graphical abstract: Nanoporous PdFe alloy, characterized by open three-dimensional bicontinuous nanospongy architecture, was easily fabricated by selectively dealloying PdFeAl source alloys, which exhibits greatly enhanced sensing performance and structure stability towards H{sub 2}O{sub 2} and glucose compared with NP-Pd and Pd/C catalysts. - Highlights: • NP-PdFe alloy is fabricated by a simple dealloying method. • NP-PdFe possesses open three-dimensional bicontinuous spongy morphology. • NP-PdFe shows high electrochemical sensing activities towards H{sub 2}O{sub 2} and glucose. • NP-PdFe shows good long-term stability for H{sub 2}O{sub 2} and glucose detection. • NP-PdFe shows good reproducibility for H{sub 2}O{sub 2} and glucose detection. - Abstract: Nanoporous (NP) PdFe alloy is easily fabricated through one step mild dealloying of PdFeAl ternary source alloy in NaOH solution. Electron microscopy characterization demonstrates that selectively dissolving Al from PdFeAl alloy generates three-dimensional bicontinuous nanospongy architecture with the typical ligament size around 5 nm. Electrochemical measurements show that the NP-PdFe alloy exhibits the superior electrocatalytic activity and durability towards hydrogen peroxide (H{sub 2}O{sub 2}) detection compared with NP-Pd and commercial Pd/C catalysts. In addition, NP-PdFe performs high sensing performance towards H{sub 2}O{sub 2} in a wide linear range from 0.5 to 6 mM with a low detection limit of 2.1 μM. This nanoporous structure also can sensitively detect glucose over a wide concentration range (1–32 mM) with a low detection limit of 1.6 μM and high resistance against chloride ions. Along with these attractive features, the as-made NP-PdFe alloy also has a good anti-interference towards ascorbic acid, uric acid, and dopamine.

  7. Prussian Blue Modified Graphene Enable Multifunctional Electrochemical Application

    DEFF Research Database (Denmark)

    Zhang, Minwei; Halder, Arnab; Hou, Chengyi

    Graphene based nanomaterials have been a hot topic since 2004. These materials have shownsome notable advantages, including large surface areas, high flexibility and reasonably good conductivityand mechanical strength, suitable for a wide range of electrochemical applications from sensors to ener...

  8. Effect of Amine Adlayer on Electrochemical Uric Acid Sensor Conducted on Electrochemically Reduced Graphene Oxide

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sumi; Kim, Kyuwon [Incheon National University, Incheon (Korea, Republic of)

    2016-03-15

    The electrochemical biosensing efficiency of uric acid (UA) detection on an electrochemically reduced graphene oxide (ERGO)-decorated electrode surface was studied by using various amine linkers used to immobilize ERGO. The amine linkers aminoethylphenyldiazonium , 2,2'-(ethylenedioxy)bis(ethylamine), 3-aminopro-pyltriethoxysilane, and polyethyleneimine were coated on indium-tin-oxide electrode surfaces through chemical or electrochemical deposition methods. ERGO-decorated surfaces were prepared by the electrochemical reduction of graphene oxide (GO), which was immobilized on the amine-coated electrode surfaces through the electrostatic interaction between GO and the ammonium ion of the linker on the surface. We monitored the sensing results of electrochemical UA detection with differential pulse voltammetry. The ERGO-modified surface presented electrocatalytic oxidation of UA and ascorbic acid. Among the different amines tested, 3-aminopropyltriethoxysilane provided the best biosensing performance in terms of sensitivity and reproducibility.

  9. Effect of Amine Adlayer on Electrochemical Uric Acid Sensor Conducted on Electrochemically Reduced Graphene Oxide

    International Nuclear Information System (INIS)

    Park, Sumi; Kim, Kyuwon

    2016-01-01

    The electrochemical biosensing efficiency of uric acid (UA) detection on an electrochemically reduced graphene oxide (ERGO)-decorated electrode surface was studied by using various amine linkers used to immobilize ERGO. The amine linkers aminoethylphenyldiazonium , 2,2'-(ethylenedioxy)bis(ethylamine), 3-aminopro-pyltriethoxysilane, and polyethyleneimine were coated on indium-tin-oxide electrode surfaces through chemical or electrochemical deposition methods. ERGO-decorated surfaces were prepared by the electrochemical reduction of graphene oxide (GO), which was immobilized on the amine-coated electrode surfaces through the electrostatic interaction between GO and the ammonium ion of the linker on the surface. We monitored the sensing results of electrochemical UA detection with differential pulse voltammetry. The ERGO-modified surface presented electrocatalytic oxidation of UA and ascorbic acid. Among the different amines tested, 3-aminopropyltriethoxysilane provided the best biosensing performance in terms of sensitivity and reproducibility.

  10. Recent advances in synthesis of three-dimensional porous graphene and its applications in construction of electrochemical (bio)sensors for small biomolecules detection.

    Science.gov (United States)

    Lu, Lu

    2018-07-01

    Electrochemical (bio)sensors have attracted much attention due to their high sensitivity, fast response time, biocompatibility, low cost and easy miniaturization. Specially, ever-growing necessity and interest have given rise to the fast development of electrochemical (bio)sensors for the detection of small biomolecules. They play enormous roles in the life processes with various biological function, such as life signal transmission, genetic expression and metabolism. Moreover, their amount in body can be used as an indicator for diagnosis of many diseases. For example, an abnormal concentration of blood glucose can indicate hyperglycemia or hypoglycemia. Graphene (GR) shows great applications in electrochemical (bio)sensors. Compared with two-dimensional (2D) GR that is inclined to stack together due to the strong π-π interaction, monolithic 3D porous GR has larger specific area, superior mechanical strength, better stability, higher conductivity and electrocatalytic activity. So they attracted more and increasing attention as sensing materials for small biomolecules. This review focuses on the recent advances and strategies in the fabrication methods of 3D porous GR and the development of various electrochemical (bio)sensors based on porous GR and its nanocomposites for the detection of small biomolecules. The challenges and future efforts direction of high-performance electrochemical (bio)sensors based on 3D porous GR for more sensitive analysis of small biomolecules are discussed and proposed. It will give readers an overall understanding of their progress and provide some theoretical guidelines for their future efforts and development. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Fabrication of highly sensitive gold nanourchins based electrochemical sensor for nanomolar determination of primaquine

    International Nuclear Information System (INIS)

    Thapliyal, Neeta Bachheti; Chiwunze, Tirivashe Elton; Karpoormath, Rajshekhar; Cherukupalli, Srinivasulu

    2017-01-01

    A gold nanourchins modified glassy carbon electrode (AuNu/GCE) was developed for the determination of antimalarial drug, primaquine (PQ). The surface of AuNu/GCE was characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and cyclic voltammetry (CV). EIS results indicated that the electron transfer process at AuNu/GCE was faster as compared to the bare electrode. The SEM and TEM image confirmed the presence and uniform dispersion of gold nanourchins on the GCE surface. Upon investigating the electrochemical behavior of PQ at AuNu/GCE, the developed sensor was found to exhibit high electrocatalytic activity towards the oxidation of PQ. Under optimal experimental conditions, the sensor showed fast and sensitive current response to PQ over a linear concentration range of 0.01–1 μM and 0.001–1 μM with a detection limit of 3.5 nM and 0.9 nM using differential pulse voltammetry (DPV) and square wave voltammetry (SWV), respectively. The AuNu/GCE showed good selectivity, reproducibility and stability. Further, the developed sensor was successfully applied to determine the drug in human urine samples and pharmaceutical formulations demonstrating its analytical applicability in clinical analysis as well as quality control. The proposed method thus provides a promising alternative in routine sensing of PQ as well as promotes the application of gold nanourchins in electrochemical sensors. - Graphical abstract: A gold nanourchins modified glassy carbon electrode was fabricated and used as an electrochemical sensing platform for the determination of primaquine. Display Omitted - Highlights: • Gold nanourchins based electrochemical sensor for determination of primaquine • A detection limit of 0.9 nM was obtained using square wave voltammetry. • Proposed method was applied to quantify the drug in tablet and human urine samples. • Fast, simple and low-cost method for trace analysis of

  12. Fabrication of highly sensitive gold nanourchins based electrochemical sensor for nanomolar determination of primaquine

    Energy Technology Data Exchange (ETDEWEB)

    Thapliyal, Neeta Bachheti, E-mail: thapliyaln@ukzn.ac.za; Chiwunze, Tirivashe Elton; Karpoormath, Rajshekhar, E-mail: karpoormath@ukzn.ac.za; Cherukupalli, Srinivasulu

    2017-05-01

    A gold nanourchins modified glassy carbon electrode (AuNu/GCE) was developed for the determination of antimalarial drug, primaquine (PQ). The surface of AuNu/GCE was characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and cyclic voltammetry (CV). EIS results indicated that the electron transfer process at AuNu/GCE was faster as compared to the bare electrode. The SEM and TEM image confirmed the presence and uniform dispersion of gold nanourchins on the GCE surface. Upon investigating the electrochemical behavior of PQ at AuNu/GCE, the developed sensor was found to exhibit high electrocatalytic activity towards the oxidation of PQ. Under optimal experimental conditions, the sensor showed fast and sensitive current response to PQ over a linear concentration range of 0.01–1 μM and 0.001–1 μM with a detection limit of 3.5 nM and 0.9 nM using differential pulse voltammetry (DPV) and square wave voltammetry (SWV), respectively. The AuNu/GCE showed good selectivity, reproducibility and stability. Further, the developed sensor was successfully applied to determine the drug in human urine samples and pharmaceutical formulations demonstrating its analytical applicability in clinical analysis as well as quality control. The proposed method thus provides a promising alternative in routine sensing of PQ as well as promotes the application of gold nanourchins in electrochemical sensors. - Graphical abstract: A gold nanourchins modified glassy carbon electrode was fabricated and used as an electrochemical sensing platform for the determination of primaquine. Display Omitted - Highlights: • Gold nanourchins based electrochemical sensor for determination of primaquine • A detection limit of 0.9 nM was obtained using square wave voltammetry. • Proposed method was applied to quantify the drug in tablet and human urine samples. • Fast, simple and low-cost method for trace analysis of

  13. Pencil It in: Exploring the Feasibility of Hand-Drawn Pencil Electrochemical Sensors and Their Direct Comparison to Screen-Printed Electrodes

    Directory of Open Access Journals (Sweden)

    Elena Bernalte

    2016-08-01

    Full Text Available We explore the fabrication, physicochemical characterisation (SEM, Raman, EDX and XPS and electrochemical application of hand-drawn pencil electrodes (PDEs upon an ultra-flexible polyester substrate; investigating the number of draws (used for their fabrication, the pencil grade utilised (HB to 9B and the electrochemical properties of an array of batches (i.e, pencil boxes. Electrochemical characterisation of the PDEs, using different batches of HB grade pencils, is undertaken using several inner- and outer-sphere redox probes and is critically compared to screen-printed electrodes (SPEs. Proof-of-concept is demonstrated for the electrochemical sensing of dopamine and acetaminophen using PDEs, which are found to exhibit competitive limits of detection (3σ upon comparison to SPEs. Nonetheless, it is important to note that a clear lack of reproducibility was demonstrated when utilising these PDEs fabricated using the HB pencils from different batches. We also explore the suitability and feasibility of a pencil-drawn reference electrode compared to screen-printed alternatives, to see if one can draw the entire sensing platform. This article reports a critical assessment of these PDEs against that of its screen-printed competitors, questioning the overall feasibility of PDEs’ implementation as a sensing platform.

  14. Applications of polymers for biomolecule immobilization in electrochemical biosensors

    International Nuclear Information System (INIS)

    Teles, F.R.R.; Fonseca, L.P.

    2008-01-01

    Polymers are becoming inseparable from biomolecule immobilization strategies and biosensor platforms. Their original role as electrical insulators has been progressively substituted by their electrical conductive abilities, which opens a new and broad scope of applications. In addition, recent advances in diagnostic chips and microfluidic systems, together with the requirements of mass-production technologies, have raised the need to replace glass by polymeric materials, which are more suitable for production through simple manufacturing processes. Conducting polymers (CPs), in particular, are especially amenable for electrochemical biosensor development for providing biomolecule immobilization and for rapid electron transfer. It is expected that the combination of known polymer substrates, but also new transducing and biocompatible interfaces, with nanobiotechnological structures, like nanoparticles, carbon nanotubes (CNTs) and nanoengineered 'smart' polymers, may generate composites with new and interesting properties, providing higher sensitivity and stability of the immobilized molecules, thus constituting the basis for new and improved analytical devices for biomedical and other applications. This review covers the state-of-the-art and main novelties about the use of polymers for immobilization of biomolecules in electrochemical biosensor platforms

  15. Fully printed metabolite sensor using organic electrochemical transistor

    Science.gov (United States)

    Scheiblin, Gaëtan; Aliane, Abdelkader; Coppard, Romain; Owens, Róisín. M.; Mailley, Pascal; Malliaras, George G.

    2015-08-01

    As conducting polymer based devices, organic electrochemical transistors (OECTs) are suited for printing process. The convenience of the screen-printing techniques allowed us to design and fabricate OECTs with a selected design and using different gate material. Depending on the material used, we were able to tune the transistor for different biological application. Ag/AgCl gate provided transistor with good transconductance, and electrochemical sensitivity to pH was provided by polyaniline ink. Finally, we validate the enzymatic sensing of glucose and lactate with a Poly(3,4-ethylene dioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) gate often used due to its biocompatible properties. The screen-printing process allowed us to fabricate a large amount of devices in a short period of time, using only commercially available grades of ink, showing by this way the possible transfer to industrial purpose.

  16. Synthesis of palladium nanoparticle modified reduced graphene oxide and multi-walled carbon nanotube hybrid structures for electrochemical applications

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jie, E-mail: hujie@tyut.edu.cn [Micro and Nano System Research Center, Key Lab of Advanced Transducers and Intelligent Control System (Ministry of Education) & College of Information Engineering, Taiyuan University of Technology, Taiyuan, 030024, Shanxi (China); Zhao, Zhenting; Zhang, Jun; Li, Gang; Li, Pengwei; Zhang, Wendong [Micro and Nano System Research Center, Key Lab of Advanced Transducers and Intelligent Control System (Ministry of Education) & College of Information Engineering, Taiyuan University of Technology, Taiyuan, 030024, Shanxi (China); Lian, Kun, E-mail: liankun@tyut.edu.cn [Micro and Nano System Research Center, Key Lab of Advanced Transducers and Intelligent Control System (Ministry of Education) & College of Information Engineering, Taiyuan University of Technology, Taiyuan, 030024, Shanxi (China); School of Nano-Science and Nano-Engineering, Suzhou & Collaborative Innovation Center of Suzhou Nano Science and Technology, Xi' an Jiaotong University, Xi' an, 710049 (China); Center for Advanced Microstructures and Devices, Louisiana State University, LA, 70806 (United States)

    2017-02-28

    Graphical abstract: A sensitive hydrazine electrochemical sensor was fabricated by using palladium (Pd) nanoparticle functionalized reduced graphene oxide (rGO) and multi-walled carbon nanotube (MWCNTs) hybrid structures (Pd/rGO-MWCNTs). - Highlights: • rGO-MWCNTs hybrid structures and Pd nanoparticles are prepared using electrochemical methods. • rGO-MWCNTs hybrid films are used as supports and co-catalysts for Pd nanoparticles. • The Pd/rGO-MWCNTs hybrid structure based sensor shows an ultra-high sensitivity of 7.09 μA μM{sup −1} cm{sup −2} and a low detection limit of 0.15 μM. • The proposed electrochemical sensor exhibits excellent selectivity. - Abstract: In this work, palladium (Pd) nanoparticles functionalized reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) hybrid structures (Pd/rGO-MWCNTs) were successfully prepared by a combination of electrochemical reduction with electrodeposition method. The morphology, structure, and composition of the Pd/rGO-MWCNTs hybrid were characterized by scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy. The as-synthesized hybrid structures were modified on the glassy carbon electrode (GCE) and further utilized for hydrazine sensing. Electrochemical impedance spectroscopic, cyclic voltammetry and single-potential amperometry experiments were carried out on Pd/rGO-MWCNTs hybrid structures to investigate the interface properties and sensing performance. The measured results demonstrate that the fabricated Pd/rGO-MWCNTs/GCE sensor show a high sensitivity of 7.09 μA μM{sup −1} cm{sup −2} in a large concentration range of 1.0 to 1100 μM and a low detection limit of 0.15 μM. Moreover, the as-prepared sensor exhibits good selectivity and stability for the determination of hydrazine under interference conditions.

  17. Synthesis of palladium nanoparticle modified reduced graphene oxide and multi-walled carbon nanotube hybrid structures for electrochemical applications

    International Nuclear Information System (INIS)

    Hu, Jie; Zhao, Zhenting; Zhang, Jun; Li, Gang; Li, Pengwei; Zhang, Wendong; Lian, Kun

    2017-01-01

    Graphical abstract: A sensitive hydrazine electrochemical sensor was fabricated by using palladium (Pd) nanoparticle functionalized reduced graphene oxide (rGO) and multi-walled carbon nanotube (MWCNTs) hybrid structures (Pd/rGO-MWCNTs). - Highlights: • rGO-MWCNTs hybrid structures and Pd nanoparticles are prepared using electrochemical methods. • rGO-MWCNTs hybrid films are used as supports and co-catalysts for Pd nanoparticles. • The Pd/rGO-MWCNTs hybrid structure based sensor shows an ultra-high sensitivity of 7.09 μA μM"−"1 cm"−"2 and a low detection limit of 0.15 μM. • The proposed electrochemical sensor exhibits excellent selectivity. - Abstract: In this work, palladium (Pd) nanoparticles functionalized reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) hybrid structures (Pd/rGO-MWCNTs) were successfully prepared by a combination of electrochemical reduction with electrodeposition method. The morphology, structure, and composition of the Pd/rGO-MWCNTs hybrid were characterized by scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy. The as-synthesized hybrid structures were modified on the glassy carbon electrode (GCE) and further utilized for hydrazine sensing. Electrochemical impedance spectroscopic, cyclic voltammetry and single-potential amperometry experiments were carried out on Pd/rGO-MWCNTs hybrid structures to investigate the interface properties and sensing performance. The measured results demonstrate that the fabricated Pd/rGO-MWCNTs/GCE sensor show a high sensitivity of 7.09 μA μM"−"1 cm"−"2 in a large concentration range of 1.0 to 1100 μM and a low detection limit of 0.15 μM. Moreover, the as-prepared sensor exhibits good selectivity and stability for the determination of hydrazine under interference conditions.

  18. Nanomaterials-based electrochemical sensors for nitric oxide

    International Nuclear Information System (INIS)

    Dang, Xueping; Hu, Hui; Wang, Shengfu; Hu, Shengshui

    2015-01-01

    Electrochemical sensing has been demonstrated to represent an efficient way to quantify nitric oxide (NO) in challenging physiological environments. A sensing interface based on nanomaterials opens up new opportunities and broader prospects for electrochemical NO sensors. This review (with 141 refs.) gives a general view of recent advances in the development of electrochemical sensors based on nanomaterials. It is subdivided into sections on (i) carbon derived nanomaterials (such as carbon nanotubes, graphenes, fullerenes), (ii) metal nanoparticles (including gold, platinum and other metallic nanoparticles); (iii) semiconductor metal oxide nanomaterials (including the oxides of titanium, aluminum, iron, and ruthenium); and finally (iv) nanocomposites (such as those formed from carbon nanomaterials with nanoparticles of gold, platinum, NiO or TiO 2 ). The various strategies are discussed, and the advances of using nanomaterials and the trends in NO sensor technology are outlooked in the final section. (author)

  19. Morphology–dependent electrochemical sensing properties of manganese dioxide–graphene oxide hybrid for guaiacol and vanillin

    International Nuclear Information System (INIS)

    Gan, Tian; Shi, Zhaoxia; Deng, Yaping; Sun, Junyong; Wang, Haibo

    2014-01-01

    Highlights: • MnO 2 with different morphologies were prepared via facile methods. • MnO 2 are loaded on GO via simply grinding which have high solubility and stability. • MnO 2 –GO exhibit high electrocatalytic activities depending on their shapes. • MnO 2 –GO is first used to the determination of guaiacol and vanillin simultaneously. - Abstract: Various morphologies of manganese dioxide (MnO 2 ) electrocatalysts, including nanoflowers, nanorods, nanotubes, nanoplates, nanowires and microspheres were prepared via facile hydrothermal synthesis and precipitation methods. By simply grinding with graphene oxide (GO), MnO 2 could be readily dissolved in water with high solubility and stability. The structures and electrochemical performances of these as–prepared MnO 2 –GO hybrids were fully characterized by various techniques, and the properties were found to be strongly dependent on morphology. As sensing materials for the simultaneous determination of guaiacol and vanillin for the first time, the nanoflowers–like MnO 2 , coupled with GO, exhibited relatively high sensitivity. The enhanced electrocatalytic activity was ascribed to the high purity, good crystallinity, and unique porous microstructure, which were favorable for transfer of electrons. These results may provide valuable insights for the development of nanostructured modified electrodes for next–generation high–performance electrochemical sensors

  20. Remote sensing applications in environmental research

    CERN Document Server

    Srivastava, Prashant K; Gupta, Manika; Islam, Tanvir

    2014-01-01

    Remote Sensing Applications in Environmental Research is the basis for advanced Earth Observation (EO) datasets used in environmental monitoring and research. Now that there are a number of satellites in orbit, EO has become imperative in today's sciences, weather and natural disaster prediction. This highly interdisciplinary reference work brings together diverse studies on remote sensing and GIS, from a theoretical background to its applications, represented through various case studies and the findings of new models. The book offers a comprehensive range of contributions by well-known scientists from around the world and opens a new window for students in presenting interdisciplinary and methodological resources on the latest research. It explores various key aspects and offers state-of-the-art research in a simplified form, describing remote sensing and GIS studies for those who are new to the field, as well as for established researchers.

  1. Electrochemical Sensing of Neurotoxic Agents Based on Their Electron Transfer Promotion Effect on an Au Electrode.

    Science.gov (United States)

    Shimada, Hiroshi; Noguchi, Shiori; Yamamoto, Masahiro; Nishiyama, Katsuhiko; Kitamura, Yusuke; Ihara, Toshihiro

    2017-06-06

    An electrochemical molecular sensor based on a new principle is reported. Nereistoxin (NRT, 4-N,N-dimethylamino-1,2-dithiolane), a naturally occurring neurotoxin (nicotinic acetylcholine receptor agonist), was adsorbed on an Au electrode via Au-S covalent bonding and accelerated the electron transfer between the electrode and the marker, ferricyanide anion. The contrast between the electrochemical responses obtained with the bare and NRT-modified Au electrodes was more pronounced at a low ionic strength of the supporting electrolyte, KCl. In the presence of 1 mM KCl, almost a 0/1 contrast between the signals was obtained through electrostatic interaction between the protonated tertiary amino group of NRT and the anionic ferricyanide ion. No current was observed with an electrode modified with mercaptopropionic acid. An unusually low ionic strength thickened the electric double layer to the degree where current was not observed with the bare electrode. The effect of the electrostatic concentration of the marker ion becomes obvious under such conditions. Commercially available NRT-related pesticides such as Cartap and Bensultap were also detected using the same format after pretreatments by hydrolysis/reduction. The present sensing method was successfully applied to human serum with satisfactory sensitivity.

  2. Applications of Silver Nanowires on Transparent Conducting Film and Electrode of Electrochemical Capacitor

    Directory of Open Access Journals (Sweden)

    Yuan-Jun Song

    2014-01-01

    Full Text Available Silver nanowire has potential applications on transparent conducting film and electrode of electrochemical capacitor due to its excellent conductivity. Transparent conducting film (G-film was prepared by coating silver nanowires on glass substrate using Meyer rod method, which exhibited better performance than carbon nanotube and graphene. The conductivity of G-film can be improved by increasing sintering temperature. Electrode of electrochemical capacitor (I-film was fabricated through the same method with G-film on indium tin oxide (ITO. CV curves of I-film under different scanning rates had obvious redox peaks, which indicated that I-film exhibited excellent electrochemical pseudocapacitance performance and good reversibility during charge/discharge process. In addition, the specific capacitance of I-film was measured by galvanostatic charge/discharge experiments, indicating that I-film exhibits high special capacitance and excellent electrochemical stability.

  3. An Enhanced Sensing Application Based on a Flexible Projected Capacitive-Sensing Mattress

    Directory of Open Access Journals (Sweden)

    Wen-Ying Chang

    2014-04-01

    Full Text Available This paper presents a cost-effective sensor system for mattresses that can classify the sleeping posture of an individual and prevent pressure ulcers. This system applies projected capacitive sensing to the field of health care. The charge time (CT method was used to sensitively and accurately measure the capacitance of the projected electrodes. The required characteristics of the projected capacitor were identified to develop large-area applications for sensory mattresses. The area of the electrodes, the use of shielding, and the increased length of the transmission line were calibrated to more accurately measure the capacitance of the electrodes in large-size applications. To offer the users comfort in the prone position, a flexible substrate was selected and covered with 16 × 20 electrodes. Compared with the static charge sensitive bed (SCSB, our proposed system-flexible projected capacitive-sensing mattress (FPCSM comes with more electrodes to increase the resolution of posture identification. As for the body pressure system (BPS, the FPCSM has advantages such as lower cost, higher aging-resistance capability, and the ability to sense the capacitance of the covered regions without physical contact. The proposed guard ring design effectively absorbs the noise and interrupts leakage paths. The projected capacitive electrode is suitable for proximity-sensing applications and succeeds at quickly recognizing the sleeping pattern of the user.

  4. Remote Sensing Image in the Application of Agricultural Tourism Planning

    Directory of Open Access Journals (Sweden)

    Guojing Fan

    2013-06-01

    Full Text Available This paper introduces the processing technology of high resolution remote sensing image, the specific making process of tourism map and different remote sensing data in the key application of tourism planning and so on. Remote sensing extracts agricultural tourism planning information, improving the scientificalness and operability of agricultural tourism planning. Therefore remote sensing image in the application of agricultural tourism planning will be the inevitable trend of tourism development.

  5. A Differential Electrochemical Readout ASIC With Heterogeneous Integration of Bio-Nano Sensors for Amperometric Sensing.

    Science.gov (United States)

    Ghoreishizadeh, Sara S; Taurino, Irene; De Micheli, Giovanni; Carrara, Sandro; Georgiou, Pantelis

    2017-10-01

    A monolithic biosensing platform is presented for miniaturized amperometric electrochemical sensing in CMOS. The system consists of a fully integrated current readout circuit for differential current measurement as well as on-die sensors developed by growing platinum nanostructures (Pt-nanoS) on top of electrodes implemented with the top metal layer. The circuit is based on the switch-capacitor technique and includes pseudodifferential integrators for concurrent sampling of the differential sensor currents. The circuit further includes a differential to single converter and a programmable gain amplifier prior to an ADC. The system is fabricated in [Formula: see text] technology and measures current within [Formula: see text] with minimum input-referred noise of [Formula: see text] and consumes [Formula: see text] from a [Formula: see text] supply. Differential sensing for nanostructured sensors is proposed to build highly sensitive and offset-free sensors for metabolite detection. This is successfully tested for bio-nano-sensors for the measurement of glucose in submilli molar concentrations with the proposed readout IC. The on-die electrodes are nanostructured and cyclic voltammetry run successfully through the readout IC to demonstrate detection of [Formula: see text].

  6. Electrochemical Synthesis of Graphene/MnO2 Nano-Composite for Application to Supercapacitor Electrode.

    Science.gov (United States)

    Jeong, Kwang Ho; Lee, Hyeon Jeong; Simpson, Michael F; Jeong, Mun

    2016-05-01

    Graphene/MnO2 nano-composite was electrochemically synthesized for application to an electrode material for electrochemical supercapacitors. The nanosized needle-like MnO2 was obtained by use of a graphene substrate. The prepared composite exhibited an ideal supercapacitive behavior. A capacitance retention of 94% was achieved with a 4 h deposition time (an initial capacitance of 574 mF/cm2 at a scan rate of 20 mV/s) and the retention declined with further deposition time. The results demonstrate enhanced contact between the electrode and electrolyte and improved power density as an electrochemical capacitor.

  7. Electroanalytical Sensing of Flunitrazepam Based on Screen Printed Graphene Electrodes

    Directory of Open Access Journals (Sweden)

    Enriqueta Garcia-Gutierrez

    2013-12-01

    Full Text Available We present a new electrochemical sensor for Flunitrazepam using disposable and economic Screen Printed Graphene Electrodes. It was found that the electrochemical response of this sensor was improved compared to Screen Printed Graphite Electrodes and displayed an excellent analytical performance for the detection of Flunitrazepam. Those characteristics could be attributed to the high Flunitrazepam loading capacity on the electrode surface and the outstanding electric conductivity of graphene. The methodology is shown to be useful for quantifying low levels of Flunitrazepam in a buffer solution. The protocol is also shown to be applicable for the sensing of Flunitrazepam in an alcoholic beverage e.g., Gordon’s Gin & Tonic.

  8. Remote Sensing: Physics And Environmental Applications

    International Nuclear Information System (INIS)

    EI Raey, M.

    2007-01-01

    Full text: Basic principles of remote sensing of environment are outlined emphasizing inherent physical and target properties leading to proper identification and classification. Basic processing techniques are discussed. Applications of remote sensing techniques in various aspects of environmental monitoring and assessment is surveyed with emphasis on aspects of main concern to developing communities such as planning, sea level impacts, mine detection and earthquake prediction are all outlined and discussed

  9. Yeast surface displaying glucose oxidase as whole-cell biocatalyst: construction, characterization, and its electrochemical glucose sensing application.

    Science.gov (United States)

    Wang, Hongwei; Lang, Qiaolin; Li, Liang; Liang, Bo; Tang, Xiangjiang; Kong, Lingrang; Mascini, Marco; Liu, Aihua

    2013-06-18

    The display of glucose oxidase (GOx) on yeast cell surface using a-agglutinin as an anchor motif was successfully developed. Both the immunochemical analysis and enzymatic assay showed that active GOx was efficiently expressed and translocated on the cell surface. Compared with conventional GOx, the yeast cell surface that displayed GOx (GOx-yeast) demonstrated excellent enzyme properties, such as good stability within a wide pH range (pH 3.5-11.5), good thermostability (retaining over 94.8% enzyme activity at 52 °C and 84.2% enzyme activity at 56 °C), and high d-glucose specificity. In addition, direct electrochemistry was achieved at a GOx-yeast/multiwalled-carbon-nanotube modified electrode, suggesting that the host cell of yeast did not have any adverse effect on the electrocatalytic property of the recombinant GOx. Thus, a novel electrochemical glucose biosensor based on this GOx-yeast was developed. The as-prepared biosensor was linear with the concentration of d-glucose within the range of 0.1-14 mM and a low detection limit of 0.05 mM (signal-to-noise ratio of S/N = 3). Moreover, the as-prepared biosensor is stable, specific, reproducible, simple, and cost-effective, which can be applicable for real sample detection. The proposed strategy to construct robust GOx-yeast may be applied to explore other oxidase-displaying-system-based whole-cell biocatalysts, which can find broad potential application in biosensors, bioenergy, and industrial catalysis.

  10. High transconductance organic electrochemical transistors

    Science.gov (United States)

    Khodagholy, Dion; Rivnay, Jonathan; Sessolo, Michele; Gurfinkel, Moshe; Leleux, Pierre; Jimison, Leslie H.; Stavrinidou, Eleni; Herve, Thierry; Sanaur, Sébastien; Owens, Róisín M.; Malliaras, George G.

    2013-07-01

    The development of transistors with high gain is essential for applications ranging from switching elements and drivers to transducers for chemical and biological sensing. Organic transistors have become well-established based on their distinct advantages, including ease of fabrication, synthetic freedom for chemical functionalization, and the ability to take on unique form factors. These devices, however, are largely viewed as belonging to the low-end of the performance spectrum. Here we present organic electrochemical transistors with a transconductance in the mS range, outperforming transistors from both traditional and emerging semiconductors. The transconductance of these devices remains fairly constant from DC up to a frequency of the order of 1 kHz, a value determined by the process of ion transport between the electrolyte and the channel. These devices, which continue to work even after being crumpled, are predicted to be highly relevant as transducers in biosensing applications.

  11. High transconductance organic electrochemical transistors

    Science.gov (United States)

    Khodagholy, Dion; Rivnay, Jonathan; Sessolo, Michele; Gurfinkel, Moshe; Leleux, Pierre; Jimison, Leslie H.; Stavrinidou, Eleni; Herve, Thierry; Sanaur, Sébastien; Owens, Róisín M.; Malliaras, George G.

    2013-01-01

    The development of transistors with high gain is essential for applications ranging from switching elements and drivers to transducers for chemical and biological sensing. Organic transistors have become well-established based on their distinct advantages, including ease of fabrication, synthetic freedom for chemical functionalization, and the ability to take on unique form factors. These devices, however, are largely viewed as belonging to the low-end of the performance spectrum. Here we present organic electrochemical transistors with a transconductance in the mS range, outperforming transistors from both traditional and emerging semiconductors. The transconductance of these devices remains fairly constant from DC up to a frequency of the order of 1 kHz, a value determined by the process of ion transport between the electrolyte and the channel. These devices, which continue to work even after being crumpled, are predicted to be highly relevant as transducers in biosensing applications. PMID:23851620

  12. Toward selective electrochemical 'E-tongue': Potentiometric DO sensor based on sub-micron ZnO-RuO{sub 2} sensing electrode

    Energy Technology Data Exchange (ETDEWEB)

    Zhuiykov, Serge, E-mail: serge.zhuiykov@csiro.au [CSIRO, Materials Science and Engineering Division, 37 Graham Road, Highett, VIC 3190 (Australia); Kats, Eugene [CSIRO, Materials Science and Engineering Division, 37 Graham Road, Highett, VIC 3190 (Australia); Plashnitsa, Vladimir [Research and Education Centre of Carbon Resources, Kyushu University, Kasuga-shi, Fukuoka 816-8580 (Japan); Miura, Norio [KASTEC, Kyushu University, Kasuga-shi, Fukuoka 816-8580 (Japan)

    2011-06-01

    Highlights: > We examine ZnO-doped RuO{sub 2} sensing electrode of DO sensor. > Study of ZnO-RuO{sub 2} confirmed the development of high surface-to-volume ratio. > Developed sensing electrode is insensitive to the presence of various dissolved salts. > 20 mol% ZnO-doped RuO{sub 2} sensing electrode enables maximum DO sensitivity. > We conclude that DO sensor based on ZnO-RuO{sub 2} electrode can work at 11-30 deg. C. - Abstract: Planar dissolved oxygen (DO) sensors based on thick-film ZnO-RuO{sub 2} sensing electrodes (SEs) with different mol% of ZnO were prepared on the alumina substrates using a screen-printing method and their structural and electrochemical properties were closely studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), electrochemical impedance spectroscopy (EIS) and energy-dispersive spectroscopy (EDS) techniques. Structural and electrochemical properties of ZnO-RuO{sub 2}-SEs have been investigated. Interference testing ascertained that the DO sensor based on sub-micron ZnO-RuO{sub 2}-SE is insensitive to the presence of various dissolved ions including Cl{sup -}, Li{sup +}, SO{sub 4}{sup 2-}, NO{sup 3-}, Ca{sup 2+}, PO{sub 4}{sup 3-}, Mg{sup 2+}, Na{sup +} and K{sup +} within a concentration range of 10{sup -7} to 10{sup -1} mol/L for DO measurement from 0.5 to 8.0 ppm in the test solution at a temperature range of 11-30 deg. C. These dissolved salts had practically no effect on the sensor's output potential difference response, whereas Br{sup -} ions had some effects at concentration more than 10{sup -3} mol/L. The relationship between DO and the sensor's potential difference was found to be relatively linear with the maximum sensitivity of -50.6 mV per decade was achieved at 20 mol% ZnO at 7.35 pH. The response and recovery time to pH changes for the planar device based on 20 mol% ZnO-RuO{sub 2}-SE was found to be 10 and 25 s

  13. Melt quenched vanadium oxide embedded in graphene oxide sheets as composite electrodes for amperometric dopamine sensing and lithium ion battery applications

    Energy Technology Data Exchange (ETDEWEB)

    Sreejesh, M. [Materials Research Laboratory, Department of Physics, National Institute of Technology Karnataka, P.O. Srinivasnagar, Surathkal, Mangaluru 575 025 (India); Shenoy, Sulakshana [Functional Nanostructured Materials Research Laboratory, Department of Physics, National Institute of Technology Karnataka, P.O. Srinivasnagar, Surathkal, Mangaluru 575 025 (India); Sridharan, Kishore, E-mail: kishore@nitk.edu.in [Functional Nanostructured Materials Research Laboratory, Department of Physics, National Institute of Technology Karnataka, P.O. Srinivasnagar, Surathkal, Mangaluru 575 025 (India); Kufian, D.; Arof, A.K. [Centre for Ionics, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Nagaraja, H.S., E-mail: nagaraja@nitk.edu.in [Materials Research Laboratory, Department of Physics, National Institute of Technology Karnataka, P.O. Srinivasnagar, Surathkal, Mangaluru 575 025 (India)

    2017-07-15

    Highlights: • Layered vanadium oxides (MVO) are prepared through melt quenching process. • MVO is hydrothermally treated with graphene oxide to form MVGO composites. • Dopamine detection capacity using MVGO is 0.07 μM with good selectivity. • Sensitivity of dopamine detection is 25.02 μA mM{sup −1} cm{sup −2}. • Discharge capacity of MVGO electrode is 200 mAhg{sup −1} after 10 cycles. - Abstract: Electrochemical sensors and lithium-ion batteries are two important topics in electrochemistry that have attracted much attention owing to their extensive applications in enzyme-free biosensors and portable electronic devices. Herein, we report a simple hydrothermal approach for synthesizing composites of melt quenched vanadium oxide embedded on graphene oxide of equal proportion (MVGO50) for the fabrication of electrodes for nonenzymatic amperometic dopamine sensor and lithium-ion battery applications. The sensing performance of MVGO50 electrodes through chronoamperometry studies in 0.1 M PBS solution (at pH 7) over a wide range of dopamine concentration exhibited a highest sensitivity of 25.02 μA mM{sup −1} cm{sup −2} with the lowest detection limit of 0.07 μM. In addition, the selective sensing capability of MVGO50 was also tested through chronoamperometry studies by the addition of a very small concentration of dopamine (10 μM) in the presence of a fairly higher concentration of uric acid (10 mM) as the interfering species. Furthermore, the reversible lithium cycling properties of MVGO50 are evaluated by galvanostatic charge-discharge cycling studies. MVGO50 electrodes exhibited enhanced rate capacity of up to 200 mAhg{sup −1} at a current of 0.1C rate and remained stable during cycling. These results indicate that MVGO composites are potential candidates for electrochemical device applications.

  14. Growth, characterization and electrochemical properties of hierarchical CuO nanostructures for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Krishnamoorthy, Karthikeyan [Nanomaterials and System Laboratory, Department of Mechanical Engineering, Jeju National University, Jeju 690 756 (Korea, Republic of); Kim, Sang-Jae, E-mail: kimsangj@jejunu.ac.kr [Nanomaterials and System Laboratory, Department of Mechanical Engineering, Jeju National University, Jeju 690 756 (Korea, Republic of); Department of Mechatronics Engineering, Jeju National University, Jeju 690 756 (Korea, Republic of)

    2013-09-01

    Graphical abstract: - Highlights: • Hierarchical CuO nanostructures were grown on Cu foil. • Monoclinic phase of CuO was grown. • XPS analysis revealed the presence of Cu(2p{sub 3/2}) and Cu(2p{sub 1/2}) on the surfaces. • Specific capacitance of 94 F/g was achieved for the CuO using cyclic voltammetry. • Impedance spectra show their pseudo capacitor applications. - Abstract: In this paper, we have investigated the electrochemical properties of hierarchical CuO nanostructures for pseudo-supercapacitor device applications. Moreover, the CuO nanostructures were formed on Cu substrate by in situ crystallization process. The as-grown CuO nanostructures were characterized using X-ray diffraction (XRD), Fourier transform-infra red spectroscopy (FT-IR), X-ray photoelectron spectroscopy and field emission-scanning electron microscope (FE-SEM) analysis. The XRD and FT-IR analysis confirm the formation of monoclinic CuO nanostructures. FE-SEM analysis shows the formation of leave like hierarchical structures of CuO with high uniformity and controlled density. The electrochemical analysis such as cyclic voltammetry and electrochemical impedance spectroscopy studies confirms the pseudo-capacitive behavior of the CuO nanostructures. Our experimental results suggest that CuO nanostructures will create promising applications of CuO toward pseudo-supercapacitors.

  15. Growth, characterization and electrochemical properties of hierarchical CuO nanostructures for supercapacitor applications

    International Nuclear Information System (INIS)

    Krishnamoorthy, Karthikeyan; Kim, Sang-Jae

    2013-01-01

    Graphical abstract: - Highlights: • Hierarchical CuO nanostructures were grown on Cu foil. • Monoclinic phase of CuO was grown. • XPS analysis revealed the presence of Cu(2p 3/2 ) and Cu(2p 1/2 ) on the surfaces. • Specific capacitance of 94 F/g was achieved for the CuO using cyclic voltammetry. • Impedance spectra show their pseudo capacitor applications. - Abstract: In this paper, we have investigated the electrochemical properties of hierarchical CuO nanostructures for pseudo-supercapacitor device applications. Moreover, the CuO nanostructures were formed on Cu substrate by in situ crystallization process. The as-grown CuO nanostructures were characterized using X-ray diffraction (XRD), Fourier transform-infra red spectroscopy (FT-IR), X-ray photoelectron spectroscopy and field emission-scanning electron microscope (FE-SEM) analysis. The XRD and FT-IR analysis confirm the formation of monoclinic CuO nanostructures. FE-SEM analysis shows the formation of leave like hierarchical structures of CuO with high uniformity and controlled density. The electrochemical analysis such as cyclic voltammetry and electrochemical impedance spectroscopy studies confirms the pseudo-capacitive behavior of the CuO nanostructures. Our experimental results suggest that CuO nanostructures will create promising applications of CuO toward pseudo-supercapacitors

  16. Rotaxane and catenane host structures for sensing charged guest species.

    Science.gov (United States)

    Langton, Matthew J; Beer, Paul D

    2014-07-15

    CONSPECTUS: The promise of mechanically interlocked architectures, such as rotaxanes and catenanes, as prototypical molecular switches and shuttles for nanotechnological applications, has stimulated an ever increasing interest in their synthesis and function. The elaborate host cavities of interlocked structures, however, can also offer a novel approach toward molecular recognition: this Account describes the use of rotaxane and catenane host systems for binding charged guest species, and for providing sensing capability through an integrated optical or electrochemical reporter group. Particular attention is drawn to the exploitation of the unusual dynamic properties of interlocked molecules, such as guest-induced shuttling or conformational switching, as a sophisticated means of achieving a selective and functional sensor response. We initially survey interlocked host systems capable of sensing cationic guests, before focusing on our accomplishments in synthesizing rotaxanes and catenanes designed for the more challenging task of selective anion sensing. In our group, we have developed the use of discrete anionic templation to prepare mechanically interlocked structures for anion recognition applications. Removal of the anion template reveals an interlocked host system, possessing a unique three-dimensional geometrically restrained binding cavity formed between the interlocked components, which exhibits impressive selectivity toward complementary anionic guest species. By incorporating reporter groups within such systems, we have developed both electrochemical and optical anion sensors which can achieve highly selective sensing of anionic guests. Transition metals, lanthanides, and organic fluorophores integrated within the mechanically bonded structural framework of the receptor are perturbed by the binding of the guest, with a concomitant change in the emission profile. We have also exploited the unique dynamics of interlocked hosts by demonstrating that an

  17. Electrochemical sensing of etoposide using carbon quantum dot modified glassy carbon electrode.

    Science.gov (United States)

    Nguyen, Hoai Viet; Richtera, Lukas; Moulick, Amitava; Xhaxhiu, Kledi; Kudr, Jiri; Cernei, Natalia; Polanska, Hana; Heger, Zbynek; Masarik, Michal; Kopel, Pavel; Stiborova, Marie; Eckschlager, Tomas; Adam, Vojtech; Kizek, Rene

    2016-04-25

    In this study, enhancement of the electrochemical signals of etoposide (ETO) measured by differential pulse voltammetry (DPV) by modifying a glassy carbon electrode (GCE) with carbon quantum dots (CQDs) is demonstrated. In comparison with a bare GCE, the modified GCE exhibited a higher sensitivity towards electrochemical detection of ETO. The lowest limit of detection was observed to be 5 nM ETO. Furthermore, scanning electron microscopy (SEM), fluorescence microscopy (FM), and electrochemical impedance spectroscopy (EIS) were employed for the further study of the working electrode surface after the modification with CQDs. Finally, the GCE modified with CQDs under optimized conditions was used to analyse real samples of ETO in the prostate cancer cell line PC3. After different incubation times (1, 3, 6, 9, 12, 18 and 24 h), these samples were then prepared prior to electrochemical detection by the GCE modified with CQDs. High performance liquid chromatography with an electrochemical detection method was employed to verify the results from the GCE modified with CQDs.

  18. Droplet-based microfluidics for dose-response assay of enzyme inhibitors by electrochemical method.

    Science.gov (United States)

    Gu, Shuqing; Lu, Youlan; Ding, Yaping; Li, Li; Zhang, Fenfen; Wu, Qingsheng

    2013-09-24

    A simple but robust droplet-based microfluidic system was developed for dose-response enzyme inhibition assay by combining concentration gradient generation method with electrochemical detection method. A slotted-vials array and a tapered tip capillary were used for reagents introduction and concentration gradient generation, and a polydimethylsiloxane (PDMS) microfluidic chip integrated with microelectrodes was used for droplet generation and electrochemical detection. Effects of oil flow rate and surfactant on electrochemical sensing were investigated. This system was validated by measuring dose-response curves of three types of acetylcholinesterase (AChE) inhibitors, including carbamate pesticide, organophosphorus pesticide, and therapeutic drugs regulating Alzheimer's disease. Carbaryl, chlorpyrifos, and tacrine were used as model analytes, respectively, and their IC50 (half maximal inhibitory concentration) values were determined. A whole enzyme inhibition assay was completed in 6 min, and the total consumption of reagents was less than 5 μL. This microfluidic system is applicable to many biochemical reactions, such as drug screening and kinetic studies, as long as one of the reactants or products is electrochemically active. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Electrochemical Energy Storage Applications of CVD Grown Niobium Oxide Thin Films.

    Science.gov (United States)

    Fiz, Raquel; Appel, Linus; Gutiérrez-Pardo, Antonio; Ramírez-Rico, Joaquín; Mathur, Sanjay

    2016-08-24

    We report here on the controlled synthesis, characterization, and electrochemical properties of different polymorphs of niobium pentoxide grown by CVD of new single-source precursors. Nb2O5 films deposited at different temperatures showed systematic phase evolution from low-temperature tetragonal (TT-Nb2O5, T-Nb2O5) to high temperature monoclinic modifications (H-Nb2O5). Optimization of the precursor flux and substrate temperature enabled phase-selective growth of Nb2O5 nanorods and films on conductive mesoporous biomorphic carbon matrices (BioC). Nb2O5 thin films deposited on monolithic BioC scaffolds produced composite materials integrating the high surface area and conductivity of the carbonaceous matrix with the intrinsically high capacitance of nanostructured niobium oxide. Heterojunctions in Nb2O5/BioC composites were found to be beneficial in electrochemical capacitance. Electrochemical characterization of Nb2O5/BioC composites showed that small amounts of Nb2O5 (as low as 5%) in conjunction with BioCarbon resulted in a 7-fold increase in the electrode capacitance, from 15 to 104 F g(-1), while imparting good cycling stability, making these materials ideally suited for electrochemical energy storage applications.

  20. Quantitative Label-Free Cell Proliferation Tracking with a Versatile Electrochemical Impedance Detection Platform

    DEFF Research Database (Denmark)

    Caviglia, Claudia; Carminati, M; Heiskanen, Arto

    2012-01-01

    optimal detection strategies. Electrochemical Impedance Spectroscopy (EIS) has been used to monitor and compare adhesion of different cell lines. HeLa cells and 3T3 fibroblasts have been cultured for 12 hours on interdigitated electrode arrays integrated into a tailor-made cell culture platform. Both......Since the use of impedance measurements for label-free monitoring of cells has become widespread but still the choice of sensing configuration is not unique though crucial for a quantitative interpretation of data, we demonstrate the application of a novel custom multipotentiostat platform to study...... vertical and coplanar interdigitated sensing configuration approaches have been used and compared on the same cell populations....

  1. Aptamer based electrochemical sensors for emerging environmental pollutants

    Directory of Open Access Journals (Sweden)

    Akhtar eHAYAT

    2014-06-01

    Full Text Available Environmental contaminants monitoring is one of the key issues in understanding and managing hazards to human health and ecosystems. In this context, aptamer based electrochemical sensors have achieved intense significance because of their capability to resolve a potentially large number of problems and challenges in environmental contamination. An aptasensor is a compact analytical device incorporating an aptamer (oligonulceotide as the sensing element either integrated within or intimately associated with a physiochemical transducer surface. Nucleic acid is well known for the function of carrying and passing genetic information, however, it has found a key role in analytical monitoring during recent years. Aptamer based sensors represent a novelty in environmental analytical science and there are great expectations for their promising performance as alternative to conventional analytical tools. This review paper focuses on the recent advances in the development of aptamer based electrochemical sensors for environmental applications with special emphasis on emerging pollutants.

  2. Applications of Nonlinear Electrochemical Impedance Spectroscopy (NLEIS)

    KAUST Repository

    Adler, S. B.

    2013-08-31

    This paper reviews the use of nonlinear electrochemical impedance spectroscopy (NLEIS) in the analysis of SOFC electrode reactions. By combining EIS and NLEIS, as well as other independent information about an electrode material, it becomes possible to establish quantitative links between electrochemical kinetics and materials properties, even when systems are unstable with time. After a brief review of the method, this paper summarizes recent results analyzing the effects of Sr segregation in thin-film LSC electrodes. © The Electrochemical Society.

  3. A Printed Organic Amplification System for Wearable Potentiometric Electrochemical Sensors.

    Science.gov (United States)

    Shiwaku, Rei; Matsui, Hiroyuki; Nagamine, Kuniaki; Uematsu, Mayu; Mano, Taisei; Maruyama, Yuki; Nomura, Ayako; Tsuchiya, Kazuhiko; Hayasaka, Kazuma; Takeda, Yasunori; Fukuda, Takashi; Kumaki, Daisuke; Tokito, Shizuo

    2018-03-02

    Electrochemical sensor systems with integrated amplifier circuits play an important role in measuring physiological signals via in situ human perspiration analysis. Signal processing circuitry based on organic thin-film transistors (OTFTs) have significant potential in realizing wearable sensor devices due to their superior mechanical flexibility and biocompatibility. Here, we demonstrate a novel potentiometric electrochemical sensing system comprised of a potassium ion (K + ) sensor and amplifier circuits employing OTFT-based pseudo-CMOS inverters, which have a highly controllable switching voltage and closed-loop gain. The ion concentration sensitivity of the fabricated K + sensor was 34 mV/dec, which was amplified to 160 mV/dec (by a factor of 4.6) with high linearity. The developed system is expected to help further the realization of ultra-thin and flexible wearable sensor devices for healthcare applications.

  4. Electrochemical sensing platforms based on the different carbon derivative incorporated interface.

    Science.gov (United States)

    Dervisevic, Muamer; Çevik, Emre; Durmuş, Zehra; Şenel, Mehmet

    2016-01-01

    their effects on the properties of these biosensors. Biosensors were prepared by Horseradish peroxidase (HRP) immobilization on the composite electrodes composed of carbon black, carbon nanofiber (CNF), extended graphite, multiwalled carbon nanotube (MWCNT), reduced graphene oxide (REGO) and poly(glycidyl methacrylateco-vinylferrocene) (P(GMA-co-VFc)) as mediator, covalent linker, and host matrix for carbon derivatives. The modified pencil graphite electrode (PGE) was used for the detection of hydrogen peroxide and to follow electrochemical behavior of different carbon derivatives which were recorded. The electrochemical characterization was investigated by cyclic voltammetry and electrochemical impedance spectroscopy methods. Amperometric measurements showed that the REGO and MWCNT modified electrodes have excellent performance in comparison with other carbon derivatives studied.

  5. One-pot hydrothermal synthesis of zirconium dioxide nanoparticles decorated reduced graphene oxide composite as high performance electrochemical sensing and biosensing platform

    International Nuclear Information System (INIS)

    Teymourian, Hazhir; Salimi, Abdollah; Firoozi, Somayeh; Korani, Aazam; Soltanian, Saied

    2014-01-01

    Graphical abstract: - Highlights: • One pot hydrothermal synthesis used for preparing of ZrO 2 NPs reduced graphene oxide. • Electrocatalytic activity of ZrO 2 /rGO improved in compared to ZrO 2 based C- materials. • ZrO 2 NPs/rGO modified GCE was used for electrocatalytic reduction of O 2 and H 2 O 2 . • ZrO 2 NPs/rGO/GCE shows excellent ability to simultaneous detection of AA,UA and DP. • With immobilization of GOX onto ZrO 2 NPs/rGO a sensitive glucose biosensor fabricated. - Abstract: We report on the synthesis of zirconium dioxide-reduced graphene oxide composite (ZrO 2 -rGO) and its application as a novel architecture for electrochemical sensing and biosensing purposes. ZrO 2 -rGO hybrid is synthesized through a simple one-step hydrothermal route, where the reduction of GO and the in-situ generation of ZrO 2 nanoparticles (NPs) occurred simultaneously. Characterization of the resultant hybrid material using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy clearly indicated the homogeneous dispersion of ZrO 2 NPs with particle sizes of ∼5 nm on rGO sheets. The potential application of ZrO 2 -rGO modified glassy carbon electrode (ZrO 2 -rGO/GC) for electroanalytical purposes was demonstrated by using several important electroactive compounds as representative examples (i.e., O 2 , hydrogen peroxide (H 2 O 2 ), glucose, ascorbic acid (AA), dopamine (DA) and uric acid (UA)). Electrochemical control experiments by using different composites of ZrO 2 /graphite, ZrO 2 /Active Carbon and ZrO 2 electrodeposited on activated GC electrode revealed that the ZrO 2 -rGO composite possessed superior electrocatalytic activitiy towards the catalytic reduction of O 2 and H 2 O 2 at more reduced overpotentials. The linear range of H 2 O 2 concentration was from 0.10 to 1340 μM with the detection limit of 20 nM (S/N = 3). Furthermore, via immobilization of glucose oxidase (GOx) enzyme onto the

  6. DARLA: Data Assimilation and Remote Sensing for Littoral Applications

    Science.gov (United States)

    2017-03-01

    at reasonable logistical or financial costs . Remote sensing provides an attractive alternative. We discuss the range of different sensors that are...DARLA: Data Assimilation and Remote Sensing for Littoral Applications Final Report Award Number: N000141010932 Andrew T. Jessup Chris Chickadel...20. Radermacher, M., M. Wengrove, J. V. de Vries, and R. Holman (2014), Applicability of video-derived bathymetry estimates to nearshore current

  7. JEarth | Analytical Remote Sensing Imagery Application for Researchers and Practitioners

    Science.gov (United States)

    Prashad, L.; Christensen, P. R.; Anwar, S.; Dickenshied, S.; Engle, E.; Noss, D.

    2009-12-01

    The ASU 100 Cities Project and the ASU Mars Space Flight Facility (MSFF) present JEarth, a set of analytical Geographic Information System (GIS) tools for viewing and processing Earth-based remote sensing imagery and vectors, including high-resolution and hyperspectral imagery such as TIMS and MASTER. JEarth is useful for a wide range of researchers and practitioners who need to access, view, and analyze remote sensing imagery. JEarth stems from existing MSFF applications: the Java application JMars (Java Mission-planning and Analysis for Remote Sensing) for viewing and analyzing remote sensing imagery and THMPROC, a web-based, interactive tool for processing imagery to create band combinations, stretches, and other imagery products. JEarth users can run the application on their desktops by installing Java-based open source software on Windows, Mac, or Linux operating systems.

  8. Biophysical applications of satellite remote sensing

    CERN Document Server

    Hanes, Jonathan

    2014-01-01

    Including an introduction and historical overview of the field, this comprehensive synthesis of the major biophysical applications of satellite remote sensing includes in-depth discussion of satellite-sourced biophysical metrics such as leaf area index.

  9. Embroidered electrochemical sensors on gauze for rapid quantification of wound biomarkers.

    Science.gov (United States)

    Liu, Xiyuan; Lillehoj, Peter B

    2017-12-15

    Electrochemical sensors are an attractive platform for analytical measurements due to their high sensitivity, portability and fast response time. These attributes also make electrochemical sensors well suited for wearable applications which require excellent flexibility and durability. Towards this end, we have developed a robust electrochemical sensor on gauze via a unique embroidery fabrication process for quantitative measurements of wound biomarkers. For proof of principle, this biosensor was used to detect uric acid, a biomarker for wound severity and healing, in simulated wound fluid which exhibits high specificity, good linearly from 0 to 800µM, and excellent reproducibility. Continuous sensing of uric acid was also performed using this biosensor which reveals that it can generate consistent and accurate measurements for up to 7h. Experiments to evaluate the robustness of the embroidered gauze sensor demonstrate that it offers excellent resilience against mechanical stress and deformation, making it a promising wearable platform for assessing and monitoring wound status in situ. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Electrochemical and surface characterisation of carbon-film-coated piezoelectric quartz crystals

    International Nuclear Information System (INIS)

    Pinto, Edilson M.; Gouveia-Caridade, Carla; Soares, David M.; Brett, Christopher M.A.

    2009-01-01

    The electrochemical properties of carbon films, of thickness between 200 and 500 nm, sputter-coated on gold- and platinum-coated 6 MHz piezoelectric quartz crystal oscillators, as new electrode materials have been investigated. Comparative studies under the same experimental conditions were performed on bulk electrodes. Cyclic voltammetry was carried out in 0.1 M KCl electrolyte solution, and kinetic parameters of the model redox systems Fe(CN) 6 3-/4- and [Ru(NH 3 ) 6 ] 3+/2+ as well as the electroactive area of the electrodes were obtained. Atomic force microscopy was used in order to examine the surface morphology of the films, and the properties of the carbon films and the electrode-solution interface were studied by electrochemical impedance spectroscopy. The results obtained demonstrate the feasibility of the preparation and development of nanometer thick carbon film modified quartz crystals. Such modified crystals should open up new opportunities for the investigation of electrode processes at carbon electrodes and for the application of electrochemical sensing associated with the EQCM.

  11. Study of interfacial phenomena for bio/chemical sensing applications

    Science.gov (United States)

    Min, Hwall

    This work presents the fundamental study of biological and chemical interfacial phenomena and (bio)chemical sensing applications using high frequency resonator arrays. To realize a versatile (bio)chemical sensing system for the fundamental study as well as their practical applications, the following three distinct components were studied and developed: i) detection platforms with high sensitivity, ii) novel innovative sensing materials with high selectivity, iii) analytical model for data interpretation. 8-pixel micromachined quartz crystal resonator (muQCR) arrays with a fundamental resonance frequency of 60 ¡V 90 MHz have been used to provide a reliable detection platform with high sensitivity. Room temperature ionic liquid (RTIL) has been explored and integrated into the sensing system as a smart chemical sensing material. The use of nanoporous gold (np-Au) enables the combination of the resonator and surface-enhanced Raman spectroscopy for both quantitative and qualitative measurement. A statistical model for the characterization of resonator behavior to study the protein adsorption kinetics is developed by random sequential adsorption (RSA) approach with the integration of an effective surface depletion theory. The investigation of the adsorption kinetics of blood proteins is reported as the fundamental study of biological phenomena using the proposed sensing system. The aim of this work is to study different aspects of protein adsorption and kinetics of adsorption process with blood proteins on different surfaces. We specifically focus on surface depletion effect in conjunction with the RSA model to explain the observed adsorption isotherm characteristics. A number of case studies on protein adsorption conducted using the proposed sensing system has been discussed. Effort is specifically made to understand adsorption kinetics, and the effect of surface on the adsorption process as well as the properties of the adsorbed protein layer. The second half of the

  12. Synthesis and Characterization of PEDOT Derivative with Carboxyl Group and Its Chemo/Bio Sensing Application as Nanocomposite, Immobilized Biological and Enhanced Optical Materials

    International Nuclear Information System (INIS)

    Zhang, Long; Wen, Yangping; Yao, Yuanyuan; Xu, Jingkun; Duan, Xuemin; Zhang, Ge

    2014-01-01

    Graphical abstract: Electropolymerization of C4-EDOT-COOH and corresponding polymer's sensing application for environmental, pharmaceutical, biology and food. -- Highlights: •C4-EDOT-COOH monomer with good solubility in water was synthesized by an efficient five-step route. •That acidic conditions were favorable for the electropolymerization of C4-EDOT-COOH. •The resulting high-quality polymer film can be employed for the fabrication of chemo/bio-sensors and optical sensors. •These as-prepared sensors can be applied to the simple, fast and sensitive detection of different analytes. -- Abstract: Various electrochemical chemo/bio-sensors and optical sensors are facilely explored for the sensitive determination of biomolecules, drug molecules, environmental pollutants, and metal ions using a carboxylic-functionalized poly(3,4-ethylenedioxythiophene) derivative (PC4), which is easily obtained by the direct electropolymerization of a water-soluble 4-((2,3-dihydrothieno[3,4-b][1,4] dioxin-2-yl) methoxy)-4-oxobutanoic acid (C4-EDOT-COOH) monomer in a microemulsion system. The effect of different pH values on the electropolymerization of C4-EDOT-COOH monomer is investigated, and the as-prepared PC4 film is characterized by electrochemical method, infrared spectrum, and scanning electron microscope. The resulting high-quality PC4 film as a sensing material not only can combine with various biologically active species via covalent linkage and inorganic materials via layer-by-layer self-assembly for the construction of electrochemical chemo/bio-sensors, but also excellent optical performance of PC4 can be employed for the fabrication of optical sensors. These as-prepared chemo/bio-sensors can be applied to the simple, fast and sensitive detection of environmental pollutants, pharmaceuticals, hazardous substances, and biological active substance and nutrients present in food by means of electrochemistry, ultraviolet and fluorescence spectroscopy. Satisfactory results

  13. Highly sensitive electrochemical detection of methyl salicylate using electroactive gold nanoparticles.

    Science.gov (United States)

    Umasankar, Yogeswaran; Ramasamy, Ramaraja P

    2013-11-07

    Electrochemical sensing of methyl salicylate, a key plant volatile has been achieved using a gold nanoparticle (AuNP) modified screen printed carbon electrode (SPCE). The electrochemical response of planar gold electrodes, SPCE and AuNP-SPCE in alkaline electrolyte in the presence and absence of methyl salicylate were studied to understand the amperometric response of various electrochemical reactions. The reaction mechanism includes hydrolysis of methyl salicylate and the oxidation of negative species. The electrochemical responses were recorded using cyclic voltammetry and differential pulse voltammetry techniques, where the results showed characteristic signals for methyl salicylate oxidation. Among the examined electrodes, AuNP-SPCE possessed three fold better sensitivity than planar gold and 35 times better sensitivity than SPCE (at 0.5 V). The methyl salicylate sensing by AuNP-SPCE possessed 95% of its methyl salicylate response. The electroanalytical results of soybean extract showed that AuNP-SPCE can be employed for the determination of methyl salicylate in real samples.

  14. Electrochemical fabrication of a novel conducting metallopolymer nanoparticles and its electrocatalytic application

    International Nuclear Information System (INIS)

    Kazemi, Sayed Habib; Mohamadi, Rahim

    2013-01-01

    Graphical abstract: Nanoparticles of nickel-curcumin conducting polymer (Ni-Curc-NPs) were fabricated by a two steps electrochemical method. In the first step, nickel source was immobilized at the electrode surface in the form of nickel nanoparticles (NiNPs). Then, electropolymerization of Ni-curcumin was performed at the NiNPs modified electrode. These nanostructures were successfully employed for electrooxidative determination of glucose and significant increase in the electrochemical sensitivity and lower limit of detection were observed. -- Highlights: • A novel two steps method for fabrication of nickel-curcumin conducting polymer was described. • Nickel-curcumine nanoparticles were easily prepared instead of thin film. • Ni-Curc-NPs modified electrode was successfully employed for electrooxidation of glucose. • Significant improvement in the sensitivity and limit of detection was observed. -- Abstract: Present article is the first example of a novel two step electrochemical route for fabrication of nanoparticles of conducting metallopolymer of Ni-curcumin (Ni-Curc-NPs). Firstly, nickel nanoparticles (Ni-NPs) were electrochemically deposited on the electrode surface. Then, electropolymerization of Ni-Curc-NPs were performed at the electrode modified with Ni-NPs. These nanostructures were characterized using electrochemical methods including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and hydrodynamic amperometry, also surface analysis methods and electron microscopy including energy dispersive analysis of X-ray (EDAX), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Additionally, application of the Ni-Curc-NPs modified electrode toward glucose electrooxidation was examined. A lower limit of detection and enhanced dynamic linear range for determination of glucose were observed at Ni-Curc-NPs modified electrode compared to Ni-NPs modified electrode

  15. Porous One-Dimensional Nanomaterials: Design, Fabrication and Applications in Electrochemical Energy Storage.

    Science.gov (United States)

    Wei, Qiulong; Xiong, Fangyu; Tan, Shuangshuang; Huang, Lei; Lan, Esther H; Dunn, Bruce; Mai, Liqiang

    2017-05-01

    Electrochemical energy storage technology is of critical importance for portable electronics, transportation and large-scale energy storage systems. There is a growing demand for energy storage devices with high energy and high power densities, long-term stability, safety and low cost. To achieve these requirements, novel design structures and high performance electrode materials are needed. Porous 1D nanomaterials which combine the advantages of 1D nanoarchitectures and porous structures have had a significant impact in the field of electrochemical energy storage. This review presents an overview of porous 1D nanostructure research, from the synthesis by bottom-up and top-down approaches with rational and controllable structures, to several important electrochemical energy storage applications including lithium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, lithium-oxygen batteries and supercapacitors. Highlights of porous 1D nanostructures are described throughout the review and directions for future research in the field are discussed at the end. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Electrochemical Biosensors - Sensor Principles and Architectures

    Directory of Open Access Journals (Sweden)

    Erik Reimhult

    2008-03-01

    Full Text Available Quantification of biological or biochemical processes are of utmost importancefor medical, biological and biotechnological applications. However, converting the biologicalinformation to an easily processed electronic signal is challenging due to the complexity ofconnecting an electronic device directly to a biological environment. Electrochemical biosensorsprovide an attractive means to analyze the content of a biological sample due to thedirect conversion of a biological event to an electronic signal. Over the past decades severalsensing concepts and related devices have been developed. In this review, the most commontraditional techniques, such as cyclic voltammetry, chronoamperometry, chronopotentiometry,impedance spectroscopy, and various field-effect transistor based methods are presented alongwith selected promising novel approaches, such as nanowire or magnetic nanoparticle-basedbiosensing. Additional measurement techniques, which have been shown useful in combinationwith electrochemical detection, are also summarized, such as the electrochemical versionsof surface plasmon resonance, optical waveguide lightmode spectroscopy, ellipsometry,quartz crystal microbalance, and scanning probe microscopy.The signal transduction and the general performance of electrochemical sensors are often determinedby the surface architectures that connect the sensing element to the biological sampleat the nanometer scale. The most common surface modification techniques, the various electrochemicaltransduction mechanisms, and the choice of the recognition receptor moleculesall influence the ultimate sensitivity of the sensor. New nanotechnology-based approaches,such as the use of engineered ion-channels in lipid bilayers, the encapsulation of enzymesinto vesicles, polymersomes, or polyelectrolyte capsules provide additional possibilities forsignal amplification.In particular, this review highlights the importance of the precise control over the

  17. Exploring microdischarges for portable sensing applications.

    Science.gov (United States)

    Gianchandani, Y B; Wright, S A; Eun, C K; Wilson, C G; Mitra, B

    2009-10-01

    This paper describes the use of microdischarges as transducing elements in sensors and detectors. Chemical and physical sensing of gases, chemical sensing of liquids, and radiation detection are described. These applications are explored from the perspective of their use in portable microsystems, with emphasis on compactness, power consumption, the ability to operate at or near atmospheric pressure (to reduce pumping challenges), and the ability to operate in an air ambient (to reduce the need for reservoirs of carrier gases). Manufacturing methods and performance results are described for selected examples.

  18. Sensing and tactile artificial muscles from reactive materials.

    Science.gov (United States)

    Conzuelo, Laura Valero; Arias-Pardilla, Joaquín; Cauich-Rodríguez, Juan V; Smit, Mascha Afra; Otero, Toribio Fernández

    2010-01-01

    Films of conducting polymers can be oxidized and reduced in a reversible way. Any intermediate oxidation state determines an electrochemical equilibrium. Chemical or physical variables acting on the film may modify the equilibrium potential, so that the film acts as a sensor of the variable. The working potential of polypyrrole/DBSA (Dodecylbenzenesulfonic acid) films, oxidized or reduced under constant currents, changes as a function of the working conditions: electrolyte concentration, temperature or mechanical stress. During oxidation, the reactive material is a sensor of the ambient, the consumed electrical energy being the sensing magnitude. Devices based on any of the electrochemical properties of conducting polymers must act simultaneously as sensors of the working conditions. Artificial muscles, as electrochemical actuators constituted by reactive materials, respond to the ambient conditions during actuation. In this way, they can be used as actuators, sensing the surrounding conditions during actuation. Actuating and sensing signals are simultaneously included by the same two connecting wires.

  19. Sonochemically Fabricated Microelectrode Arrays for Use as Sensing Platforms

    Directory of Open Access Journals (Sweden)

    Stuart D. Collyer

    2010-05-01

    Full Text Available The development, manufacture, modification and subsequent utilisation of sonochemically-formed microelectrode arrays is described for a range of applications. Initial fabrication of the sensing platform utilises ultrasonic ablation of electrochemically insulating polymers deposited upon conductive carbon substrates, forming an array of up to 70,000 microelectrode pores cm–2. Electrochemical and optical analyses using these arrays, their enhanced signal response and stir-independence area are all discussed. The growth of conducting polymeric “mushroom” protrusion arrays with entrapped biological entities, thereby forming biosensors is detailed. The simplicity and inexpensiveness of this approach, lending itself ideally to mass fabrication coupled with unrivalled sensitivity and stir independence makes commercial viability of this process a reality. Application of microelectrode arrays as functional components within sensors include devices for detection of chlorine, glucose, ethanol and pesticides. Immunosensors based on microelectrode arrays are described within this monograph for antigens associated with prostate cancer and transient ischemic attacks (strokes.

  20. Terahertz Sensing, Imaging and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Otani, C.; Hoshing, H.; Sasaki, Y.; Maki, K.; Hayashi, A. [RIKEN Advanced Science Institute, Sendai (Japan)

    2008-11-15

    Diagnosis using terahertz (THz) wave holds a great potential for various applications in various fields because of its transmittance to many soft materials with the good spatial resolution. In addition, the presence of specific spectral absorption features of crystalline materials is also important for many applications. Such features are different from material to material to material and is applicable for identifying materials inside packages that are opaque to visible light. One of the most impressive examples of such applications is the detection of illicit drugs inside envelopes. In this talk, we will present our recent topics of THz sensing, imaging and applications including this example. We will also present the cancer diagnosis, an application of the photonic crystal to high sensitivity detection, and gas spectroscopy if we have enough time. We also would like to briefly review the recent topics related to THz applications.

  1. Terahertz Sensing, Imaging and Applications

    International Nuclear Information System (INIS)

    Otani, C.; Hoshing, H.; Sasaki, Y.; Maki, K.; Hayashi, A.

    2008-01-01

    Diagnosis using terahertz (THz) wave holds a great potential for various applications in various fields because of its transmittance to many soft materials with the good spatial resolution. In addition, the presence of specific spectral absorption features of crystalline materials is also important for many applications. Such features are different from material to material to material and is applicable for identifying materials inside packages that are opaque to visible light. One of the most impressive examples of such applications is the detection of illicit drugs inside envelopes. In this talk, we will present our recent topics of THz sensing, imaging and applications including this example. We will also present the cancer diagnosis, an application of the photonic crystal to high sensitivity detection, and gas spectroscopy if we have enough time. We also would like to briefly review the recent topics related to THz applications

  2. One-pot hydrothermal synthesis, characterization and electrochemical properties of CuS nanoparticles towards supercapacitor applications

    International Nuclear Information System (INIS)

    Krishnamoorthy, Karthikeyan; Rao, Alluri Nagamalleswara; Jae Kim, Sang; Kumar Veerasubramani, Ganesh

    2014-01-01

    In this article, we have investigated the electrochemical properties of CuS nanoparticles for supercapacitor applications. The CuS nanoparticles are prepared by a facile one-pot hydrothermal approach using copper nitrate and thiourea as starting materials. The x-ray diffraction study revealed the formation of covellite CuS. The field-emission scanning electron microscope studies suggested the formation of cubic shaped CuS nanoparticles. The electrochemical studies such as cyclic voltammetry, galvanostatic charge-discharge analysis and electrochemical impedance spectroscopy confirmed the pseudocapacitive nature of the CuS electrodes. The CuS electrode shows a specific capacitance of about 101.34 F g −1 from the cyclic voltammetry at a scan rate of 5 mV s −1 . The electrochemical impedance spectra analyzed using Nyquist plot confirmed the pseudocapacitive behavior of the CuS electrodes. (paper)

  3. Synthesis and Thermophysical Properties of Ether-Functionalized Sulfonium Ionic Liquids as Potential Electrolytes for Electrochemical Applications.

    Science.gov (United States)

    Coadou, Erwan; Goodrich, Peter; Neale, Alex R; Timperman, Laure; Hardacre, Christopher; Jacquemin, Johan; Anouti, Mérièm

    2016-12-05

    During this work, a novel series of hydrophobic room temperature ionic liquids (ILs) based on five ether functionalized sulfonium cations bearing the bis{(trifluoromethyl)sulfonyl}imide, [NTf 2 ] - anion were synthesized and characterized. Their physicochemical properties, such as density, viscosity and ionic conductivity, electrochemical window, along with thermal properties including phase transition behavior and decomposition temperature, have been measured. All of these ILs showed large liquid range temperature, low viscosity, and good conductivity. Additionally, by combining DFT calculations along with electrochemical characterization it appears that these novel ILs show good electrochemical stability windows, suitable for the potential application as electrolyte materials in electrochemical energy storage devices. ©2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  4. Landsat's role in ecological applications of remote sensing.

    Science.gov (United States)

    Warren B. Cohen; Samuel N. Goward

    2004-01-01

    Remote sensing, geographic information systems, and modeling have combined to produce a virtual explosion of growth in ecological investigations and applications that are explicitly spatial and temporal. Of all remotely sensed data, those acquired by landsat sensors have played the most pivotal role in spatial and temporal scaling. Modern terrestrial ecology relies on...

  5. One-pot preparation of PEDOT:PSS-reduced graphene decorated with Au nanoparticles for enzymatic electrochemical sensing of H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mercante, Luiza A., E-mail: lamercante@gmail.com [National Laboratory for Nanotechnology in Agribusiness (LNNA), Embrapa Instrumentation, 13560-970, São Carlos, SP (Brazil); Facure, Murilo H.M. [National Laboratory for Nanotechnology in Agribusiness (LNNA), Embrapa Instrumentation, 13560-970, São Carlos, SP (Brazil); Center for Exact Sciences and Technology, Federal University of São Carlos (UFSCar), 13565-905, São Carlos, SP (Brazil); Sanfelice, Rafaela C.; Migliorini, Fernanda L.; Mattoso, Luiz H.C. [National Laboratory for Nanotechnology in Agribusiness (LNNA), Embrapa Instrumentation, 13560-970, São Carlos, SP (Brazil); Correa, Daniel S., E-mail: daniel.correa@embrapa.br [National Laboratory for Nanotechnology in Agribusiness (LNNA), Embrapa Instrumentation, 13560-970, São Carlos, SP (Brazil); Center for Exact Sciences and Technology, Federal University of São Carlos (UFSCar), 13565-905, São Carlos, SP (Brazil)

    2017-06-15

    Highlights: • Hybrid ternary nanocomposite PEDOT:PSS-rGO-AuNPs is developed by a one-step approach. • Horseradish peroxidase is used to build a novel hybrid biomaterial. • The PEDOT:PSS-rGO-AuNPs-HRP displays excellent electrochemical activity toward the reduction of H{sub 2}O{sub 2}. • A significant low detection limit of 0.08 μM and wider linear range is achieved. • The constructed electrode is used detecting H{sub 2}O{sub 2} in real samples. - Abstract: The development of novel graphene-based nanocomposites is a hotspot in materials science due to their unique optical, electronic, thermal, mechanical and catalytic properties for varied applications. The present work reports on the development of a graphene-based ternary nanocomposite of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), reduced graphene oxide and gold nanoparticles (PEDOT:PSS-rGO-AuNPs) for the detection of hydrogen peroxide (H{sub 2}O{sub 2}). The hybrid nanocomposite showed superior electrochemical properties and higher stability compared to each individual component as electrode materials, showing a synergistic effect between PEDOT, rGO and AuNPs. The nanocomposite was obtained via a facile one-step approach and was assembly with horseradish peroxidase (HRP). The PEDOT:PSS-rGO-AuNPs-HRP modified electrode has been used for the amperometric detection of H{sub 2}O{sub 2} and exhibited a high sensitivity of up to 677 μA mM{sup −1} cm{sup −2}, with a wide linear range from 5 to 400 μM and a low detection limit of 0.08 μM (S/N = 3). This developed enzymatic biosensor showed to be highly stable and unresponsive to potentially interfering substances, and it could be used for sensing H{sub 2}O{sub 2} in real samples, including tap water and bovine milk samples. These enhanced sensing performance could be ascribed to the intimate contact of AuNPs onto the rough surface of the PEDOT:PSS-rGO nanocomposite, which has a high electrical conductivity and large surface area, providing

  6. Electrochemical, morphological and microstructural characterization of carbon film resistor electrodes for application in electrochemical sensors

    International Nuclear Information System (INIS)

    Gouveia-Caridade, Carla; Soares, David M.; Liess, Hans-Dieter; Brett, Christopher M.A.

    2008-01-01

    The electrochemical and microstructural properties of carbon film electrodes made from carbon film electrical resistors of 1.5, 15, 140 Ω and 2.0 kΩ nominal resistance have been investigated before and after electrochemical pre-treatment at +0.9 V vs SCE, in order to assess the potential use of these carbon film electrodes as electrochemical sensors and as substrates for sensors and biosensors. The results obtained are compared with those at electrodes made from previously investigated 2 Ω carbon film resistors. Cyclic voltammetry was performed in acetate buffer and phosphate buffer saline electrolytes and the kinetic parameters of the model redox system Fe(CN) 6 3-/4- obtained. The 1.5 Ω resistor electrodes show the best properties for sensor development with wide potential windows, similar electrochemical behaviour to those of 2 Ω and close-to-reversible kinetic parameters after electrochemical pre-treatment. The 15 and 140 Ω resistor electrodes show wide potential windows although with slower kinetics, whereas the 2.0 kΩ resistor electrodes show poor cyclic voltammetric profiles even after pre-treatment. Electrochemical impedance spectroscopy related these findings to the interfacial properties of the electrodes. Microstructural and morphological studies were carried out using contact mode Atomic Force Microscopy (AFM), Confocal Raman spectroscopy and X-ray diffraction. AFM showed more homogeneity of the films with lower nominal resistances, related to better electrochemical characteristics. X-ray diffraction and Confocal Raman spectroscopy indicate the existence of a graphitic structure in the carbon films

  7. Point of care with micro fluidic paper based device integrated with nano zeolite-graphene oxide nanoflakes for electrochemical sensing of ketamine.

    Science.gov (United States)

    Narang, Jagriti; Malhotra, Nitesh; Singhal, Chaitali; Mathur, Ashish; Chakraborty, Dhritiman; Anil, Anusree; Ingle, Aviraj; Pundir, Chandra S

    2017-02-15

    The present study was aimed to develop an ultrasensitive technique for electroanalysis of ketamine; a date rape drug. It involved the fabrication of nano-hybrid based electrochemical micro fluidic paper-based analytical device (EμPADs) for electrochemical sensing of ketamine. A paper chip was developed using zeolites nanoflakes and graphene-oxide nanocrystals (Zeo-GO). EμPAD offers many advantages such as facile approach, economical and potential for commercialization. Nanocrystal modified EμPAD showed wide linear range 0.001-5nM/mL and a very low detection limit of 0.001nM/mL. The developed sensor was tested in real time samples like alcoholic and non-alcoholic drinks and found good correlation (99%). The hyphenation of EμPAD integrated with nanocrystalline Zeo-GO for detection of ketamine has immense prospective for field-testing platforms. An extensive development could be made for industrial translation of this fabricated device. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Remote sensing of wetlands applications and advances

    CERN Document Server

    Tiner, Ralph W; Klemas, Victor V

    2015-01-01

    Effectively Manage Wetland Resources Using the Best Available Remote Sensing Techniques Utilizing top scientists in the wetland classification and mapping field, Remote Sensing of Wetlands: Applications and Advances covers the rapidly changing landscape of wetlands and describes the latest advances in remote sensing that have taken place over the past 30 years for use in mapping wetlands. Factoring in the impact of climate change, as well as a growing demand on wetlands for agriculture, aquaculture, forestry, and development, this text considers the challenges that wetlands pose for remote sensing and provides a thorough introduction on the use of remotely sensed data for wetland detection. Taking advantage of the experiences of more than 50 contributing authors, the book describes a variety of techniques for mapping and classifying wetlands in a multitude of environments ranging from tropical to arctic wetlands including coral reefs and submerged aquatic vegetation. The authors discuss the advantages and di...

  9. Electrochemical performance of porous diamond-like carbon electrodes for sensing hormones, neurotransmitters, and endocrine disruptors.

    Science.gov (United States)

    Silva, Tiago A; Zanin, Hudson; May, Paul W; Corat, Evaldo J; Fatibello-Filho, Orlando

    2014-12-10

    Porous diamond-like carbon (DLC) electrodes have been prepared, and their electrochemical performance was explored. For electrode preparation, a thin DLC film was deposited onto a densely packed forest of highly porous, vertically aligned multiwalled carbon nanotubes (VACNT). DLC deposition caused the tips of the carbon nanotubes to clump together to form a microstructured surface with an enlarged surface area. DLC:VACNT electrodes show fast charge transfer, which is promising for several electrochemical applications, including electroanalysis. DLC:VACNT electrodes were applied to the determination of targeted molecules such as dopamine (DA) and epinephrine (EP), which are neurotransmitters/hormones, and acetaminophen (AC), an endocrine disruptor. Using simple and low-cost techniques, such as cyclic voltammetry, analytical curves in the concentration range from 10 to 100 μmol L(-1) were obtained and excellent analytical parameters achieved, including high analytical sensitivity, good response stability, and low limits of detection of 2.9, 4.5, and 2.3 μmol L(-1) for DA, EP, and AC, respectively.

  10. Development and application of the electrochemical etching technique. Annual progress report

    International Nuclear Information System (INIS)

    1979-08-01

    This report documents advances in the development and application of the electrochemical etching technique for thermal and epithermal neutron dosimetry as well as track geometry determinations. The bulk and track etching rates were studied by evaluating the track geometry during electrochemical etching. The foil surface removed versus etching time for two different etchants at 1000 V, 2 kHz, and 22 0 C were studied. Results indicated that the bulk etching rates were constant for the two etchants, i.e. 45% KOH and 45% KOH mixed with an equal volume of C 2 H 5 OH 5 and were equal to 0.20 +- 0.14 μm/hr and 2.7 +- 0.27 μm/hr from each side of the foil. The track etching rate (as contrasted with the bulk etching rate) can be determined by the microscope focus at various depths. The increase of track depth values as a function of etching time for the two etchants are plotted. The track cone angles were determined and found to be much larger for electrochemically etched polycarbonate foils than for most plastics etched with passive chemical techniques

  11. Review of Remote Sensing Needs and Applications in Africa

    Science.gov (United States)

    Brown, Molly E.

    2007-01-01

    Remote sensing data has had an important role in identifying and responding to inter-annual variations in the African environment during the past three decades. As a largely agricultural region with diverse but generally limited government capacity to acquire and distribute ground observations of rainfall, temperature and other parameters, remote sensing is sometimes the only reliable measure of crop growing conditions in Africa. Thus, developing and maintaining the technical and scientific capacity to analyze and utilize satellite remote sensing data in Africa is critical to augmenting the continent's local weather/climate observation networks as well as its agricultural and natural resource development and management. The report Review of Remote Sensing Needs and Applications in Africa' has as its central goal to recommend to the US Agency for International Development an appropriate approach to support sustainable remote sensing applications at African regional remote sensing centers. The report focuses on "RS applications" to refer to the acquisition, maintenance and archiving, dissemination, distribution, analysis, and interpretation of remote sensing data, as well as the integration of interpreted data with other spatial data products. The report focuses on three primary remote sensing centers: (1) The AGRHYMET Regional Center in Niamey, Niger, created in 1974, is a specialized institute of the Permanent Interstate Committee for Drought Control in the Sahel (CILSS), with particular specialization in science and techniques applied to agricultural development, rural development, and natural resource management. (2) The Regional Centre for Maiming of Resources for Development (RCMRD) in Nairobi, Kenya, established in 1975 under the auspices of the United Nations Economic Commission for Africa and the Organization of African Unity (now the African Union), is an intergovernmental organization, with 15 member states from eastern and southern Africa. (3) The

  12. Surface holograms for sensing application

    Science.gov (United States)

    Zawadzka, M.; Naydenova, I.

    2018-01-01

    Surface gratings with periodicity of 2 μm and amplitude in the range of 175 and 240 nm were fabricated in a plasticized polyvinylchloride doped with a metalloporphyrin (ZnTPP), via a single laser pulse holographic ablation process. The effect of the laser pulse energy on the profiles of the fabricated surface structure was investigated. The sensing capabilities of the fabricated diffractive structures towards amines (triethylamine, diethylamine) and pyridine vapours were then explored; the holographic structures were exposed to the analyte vapours and changes in the intensity of the diffracted light were monitored in real time at 473 nm. It was demonstrated that surface structures, fabricated in a polymer doped with a metalloporphyrin which acts as analyte receptor, have a potential in sensing application.

  13. Printing graphene-carbon nanotube-ionic liquid gel on graphene paper: Towards flexible electrodes with efficient loading of PtAu alloy nanoparticles for electrochemical sensing of blood glucose.

    Science.gov (United States)

    He, Wenshan; Sun, Yimin; Xi, Jiangbo; Abdurhman, Abduraouf Alamer Mohamed; Ren, Jinghua; Duan, Hongwei

    2016-01-15

    The increasing demands for portable, wearable, and implantable sensing devices have stimulated growing interest in innovative electrode materials. In this work, we have demonstrated that printing a conductive ink formulated by blending three-dimensional (3D) porous graphene-carbon nanotube (CNT) assembly with ionic liquid (IL) on two-dimensional (2D) graphene paper (GP), leads to a freestanding GP supported graphene-CNT-IL nanocomposite (graphene-CNT-IL/GP). The incorporation of highly conductive CNTs into graphene assembly effectively increases its surface area and improves its electrical and mechanical properties. The graphene-CNT-IL/GP, as freestanding and flexible substrates, allows for efficient loading of PtAu alloy nanoparticles by means of ultrasonic-electrochemical deposition. Owing to the synergistic effect of PtAu alloy nanoparticles, 3D porous graphene-CNT scaffold, IL binder and 2D flexible GP substrate, the resultant lightweight nanohybrid paper electrode exhibits excellent sensing performances in nonenzymatic electrochemical detection of glucose in terms of sensitivity, selectivity, reproducibility and mechanical properties. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Remote sensing applications for the dam industry

    Energy Technology Data Exchange (ETDEWEB)

    Pryse-Phillips, A.; Woolgar, R. [Hatch Ltd., St. John' s, NL (Canada); Puestow, T.; Warren, S. [Memorial Univ. of Newfoundland, St. John' s, NL (Canada). C-Core; Rogers, K. [Nalcor Energy, St. John' s, NL (Canada); Khan, A. [Government of Newfoundland and Labrador, St. Johns, NL (Canada)

    2009-07-01

    There has been an increase in the earth observation missions providing satellite imagery for operational monitoring applications. This technique has been found to be especially useful for the surveillance of large, remote areas, which is challenging to achieve in a cost-effective manner by conventional field-based or aerial means. This paper discussed the utility of satellite-based monitoring for different applications relevant to hydrology and water resources management. Emphasis was placed on the monitoring of river ice covers in near, real-time and water resources management. The paper first outlined river ice monitoring using remote sensing on the Lower Churchill River. The benefits of remote sensing over traditional survey methods for the dam industry was then outlined. Satellite image acquisition and interpretation for the Churchill River was then presented. Several images were offered. Watershed physiographic characterization using remote sensing was also described. It was concluded that satellite imagery proved to be a useful tool to develop physiographic characteristics when conducting rainfall-runoff modelling. 3 refs., 1 tab., 11 figs.

  15. Novel synthesis of Prussian blue nanoparticles and nanocomposite sol: Electro-analytical application in hydrogen peroxide sensing

    International Nuclear Information System (INIS)

    Pandey, Prem C.; Pandey, Ashish K.

    2013-01-01

    Highlights: ► Novel process for the synthesis of PBNPs sol of 15.8 nm size is reported. ► The PBNPs sol shows the electron transfer rate constant to the order of 32.1 s −1 ► The PBNPs sol has shown the functional activity for making the nanocomposite. ► The nanocomposite with tris(2,2′-bipyridyl)ruthenium shows photoluminiscent ability. ► The PBNPs and its nanocomposite (PB-Rubpy) show high sensitivity for H 2 O 2 sensing. - Abstract: This paper reports a new method for the synthesis of Prussian blue nanoparticles (PBNPs) sol of homogeneous dispersion with average particle size to the order of 15.8 nm. The new method of PBNPs sol synthesis is based on the interaction of active concentrations of 3-aminopropylalkoxysilane, cyclohexanone and single precursor potassium ferricyanide under ambient conditions. The PBNPs sol shows excellent electrochemistry with electron transfer rate constant to the order of 32.1 s −1 . The resulting PBNPs sol has been found highly stable for practical applications and shows functional activity for making nanocomposite sol with tris(2,2′-bipyridyl) ruthenium (Rubpy). The PB-Rubpy nanocomposite shows high sensitivity for H 2 O 2 electrochemical sensing to the order of 1102.0 μA mM −1 cm −2 and storage stability of the materials for more than 3 months. In addition, these nanocomposite exhibits excellent electrocatalytic property for hydrogen peroxide (H 2 O 2 ) sensing with catalytic rate constant to the order of 3.14 × 10 3 M −1 s −1 . The PB-Rubpy nanocomposite sol, apart from electrocatalytic application, shows photoluminiscent ability for many opto-electroanalytical applications. In addition to that functional property of PBNPs sol for making nanodispersion with several known nanoparticles of gold, silver, palladium along with in situ synthesis of mixed metal hexacyanoferrate have also been observed.

  16. DFB laser diodes for sensing applications using photoacoustic spectroscopy

    International Nuclear Information System (INIS)

    Koeth, J; Fischer, M; Legge, M; Seufert, J; Roessner, K; Groninga, H

    2010-01-01

    We present typical device characteristics of novel DFB laser diodes which are employed in various sensing applications including high resolution photoacoustic spectroscopy. The laser diodes discussed are based on a genuine fabrication technology which allows for the production of ultra stable devices within a broad spectral range from 760 nm up to 3000 nm wavelength. The devices exhibit narrow linewidths down to <1 MHz which makes them ideally suited for all photoacoustic sensing applications where a high spectral purity is required. As an example we will focus on a typical medical application where these diodes are used for breath analysis using photoacoustic spectroscopy.

  17. MOSDEN: A Scalable Mobile Collaborative Platform for Opportunistic Sensing Applications

    Directory of Open Access Journals (Sweden)

    Prem Prakash Jayaraman

    2014-05-01

    Full Text Available Mobile smartphones along with embedded sensors have become an efficient enabler for various mobile applications including opportunistic sensing. The hi-tech advances in smartphones are opening up a world of possibilities. This paper proposes a mobile collaborative platform called MOSDEN that enables and supports opportunistic sensing at run time. MOSDEN captures and shares sensor data acrossmultiple apps, smartphones and users. MOSDEN supports the emerging trend of separating sensors from application-specific processing, storing and sharing. MOSDEN promotes reuse and re-purposing of sensor data hence reducing the efforts in developing novel opportunistic sensing applications. MOSDEN has been implemented on Android-based smartphones and tablets. Experimental evaluations validate the scalability and energy efficiency of MOSDEN and its suitability towards real world applications. The results of evaluation and lessons learned are presented and discussed in this paper.

  18. Electrochemical Analysis of Neurotransmitters

    Science.gov (United States)

    Bucher, Elizabeth S.; Wightman, R. Mark

    2015-07-01

    Chemical signaling through the release of neurotransmitters into the extracellular space is the primary means of communication between neurons. More than four decades ago, Ralph Adams and his colleagues realized the utility of electrochemical methods for the study of easily oxidizable neurotransmitters, such as dopamine, norepinephrine, and serotonin and their metabolites. Today, electrochemical techniques are frequently coupled to microelectrodes to enable spatially resolved recordings of rapid neurotransmitter dynamics in a variety of biological preparations spanning from single cells to the intact brain of behaving animals. In this review, we provide a basic overview of the principles underlying constant-potential amperometry and fast-scan cyclic voltammetry, the most commonly employed electrochemical techniques, and the general application of these methods to the study of neurotransmission. We thereafter discuss several recent developments in sensor design and experimental methodology that are challenging the current limitations defining the application of electrochemical methods to neurotransmitter measurements.

  19. Application of electrochemical processes to membrane bioreactors for improving nutrient removal and fouling control.

    Science.gov (United States)

    Borea, Laura; Naddeo, Vincenzo; Belgiorno, Vincenzo

    2017-01-01

    Membrane bioreactor (MBR) technology is becoming increasingly popular as wastewater treatment due to the unique advantages it offers. However, membrane fouling is being given a great deal of attention so as to improve the performance of this type of technology. Recent studies have proven that the application of electrochemical processes to MBR represents a promising technological approach for membrane fouling control. In this work, two intermittent voltage gradients of 1 and 3 V/cm were applied between two cylindrical perforated electrodes, immersed around a membrane module, at laboratory scale with the aim of investigating the treatment performance and membrane fouling formation. For comparison purposes, the reactor also operated as a conventional MBR. Mechanisms of nutrient removal were studied and membrane fouling formation evaluated in terms of transmembrane pressure variation over time and sludge relative hydrophobicity. Furthermore, the impact of electrochemical processes on transparent exopolymeric particles (TEP), proposed as a new membrane fouling precursor, was investigated in addition to conventional fouling precursors such as bound extracellular polymeric substances (bEPS) and soluble microbial products (SMP). All the results indicate that the integration of electrochemical processes into a MBR has the advantage of improving the treatment performance especially in terms of nutrient removal, with an enhancement of orthophosphate (PO 4 -P) and ammonia nitrogen (NH 4 -N) removal efficiencies up to 96.06 and 69.34 %, respectively. A reduction of membrane fouling was also observed with an increase of floc hydrophobicity to 71.72 %, a decrease of membrane fouling precursor concentrations, and, thus, of membrane fouling rates up to 54.33 %. The relationship found between TEP concentration and membrane fouling rate after the application of electrochemical processes confirms the applicability of this parameter as a new membrane fouling indicator.

  20. Target-induced formation of gold amalgamation on DNA-based sensing platform for electrochemical monitoring of mercury ion coupling with cycling signal amplification strategy

    International Nuclear Information System (INIS)

    Chen, Jinfeng; Tang, Juan; Zhou, Jun; Zhang, Lan; Chen, Guonan; Tang, Dianping

    2014-01-01

    Graphical abstract: -- Highlights: •We report a new electrochemical sensing protocol for the detection of mercury ion. •Gold amalgamation on DNA-based sensing platform was used as nanocatalyst. •The signal was amplified by cycling signal amplification strategy. -- Abstract: Heavy metal ion pollution poses severe risks in human health and environmental pollutant, because of the likelihood of bioaccumulation and toxicity. Driven by the requirement to monitor trace-level mercury ion (Hg 2+ ), herein we construct a new DNA-based sensor for sensitive electrochemical monitoring of Hg 2+ by coupling target-induced formation of gold amalgamation on DNA-based sensing platform with gold amalgamation-catalyzed cycling signal amplification strategy. The sensor was simply prepared by covalent conjugation of aminated poly-T (25) oligonucleotide onto the glassy carbon electrode by typical carbodiimide coupling. Upon introduction of target analyte, Hg 2+ ion was intercalated into the DNA polyion complex membrane based on T–Hg 2+ –T coordination chemistry. The chelated Hg 2+ ion could induce the formation of gold amalgamation, which could catalyze the p-nitrophenol with the aid of NaBH 4 and Ru(NH 3 ) 6 3+ for cycling signal amplification. Experimental results indicated that the electronic signal of our system increased with the increasing Hg 2+ level in the sample, and has a detection limit of 0.02 nM with a dynamic range of up to 1000 nM Hg 2+ . The strategy afforded exquisite selectivity for Hg 2+ against other environmentally related metal ions. In addition, the methodology was evaluated for the analysis of Hg 2+ in spiked tap-water samples, and the recovery was 87.9–113.8%

  1. A silicon-based electrochemical sensor for highly sensitive, specific, label-free and real-time DNA detection

    International Nuclear Information System (INIS)

    Guo, Yuanyuan; Su, Shao; Wei, Xinpan; Zhong, Yiling; Su, Yuanyuan; He, Yao; Huang, Qing; Fan, Chunhai

    2013-01-01

    We herein present a new kind of silicon-based electrochemical sensor using a gold nanoparticles-decorated silicon wafer (AuNPs@Si) as a high-performance electrode, which is facilely prepared via in situ AuNPs growth on a silicon wafer. Particularly significantly, the resultant electrochemical sensor is efficacious for label-free DNA detection with high sensitivity due to the unique merits of the prepared silicon-based electrode. Typically, DNA at remarkably low concentrations (1–10 fM) could be readily detected without requiring additional signal-amplification procedures, which is better than or comparable to the lowest DNA concentration ever detected via well-studied signal-amplification-assisted electrochemical sensors. Moreover, the silicon-based sensor features high specificity, allowing unambiguous discrimination of single-based mismatches. We further show that real-time DNA assembly is readily monitored via recording the intensity changes of current signals due to the robust thermal stability of the silicon-based electrode. The unprecedented advantages of the silicon-based electrochemical sensor would offer new opportunities for myriad sensing applications. (paper)

  2. Advances on application of remote sensing technology to uranium prospecting in northwest of China

    International Nuclear Information System (INIS)

    Ye Fawang; Liu Dechang; Zhao Yingjun; Zhang Jielin; Fang Maolong

    2012-01-01

    Some advances on application of remote sensing technology to uranium prospecting in northwest of China since 21st century are presented in this paper. They included: (1) application of ETM multi-spectral remote sensing technology to identify the sandstone-type uranium ore-controlling structure in north of Ordos Basin and investigate the uranium metallogenetic geological conditions in Qiangtang Basin, Tibet, (2) application of ASTER multi-spectral and QuickBird high spatial resolution remote sensing technology to extract and analyze the oil-gas reduced alteration in Bashibulake uranium ore district, Xinjiang, (3) discovery of Salamubulake uranium metallogenetic belt in Keping, Xinjiang, using ASTER multi-spectral, QuickBird high spatial resolution, and CASI/SASI airborne hyper-spectral remote sensing comprehensively, and (4) application of CASI/SASI airborne hyper-spectral remote sensing technology to extract volcanicrock type uranium mineralization alteration in Baiyanghe area, Xinjiang. These application advances show the good application effects of remote sensing technology to uranium exploration in northwest of China, which provides important references for making further uranium prospecting using remote sensing technology. (authors)

  3. Synthesis and application of bismuth ferrite nanosheets supported functionalized carbon nanofiber for enhanced electrochemical detection of toxic organic compound in water samples.

    Science.gov (United States)

    Ramaraj, Sukanya; Mani, Sakthivel; Chen, Shen-Ming; Kokulnathan, Thangavelu; Lou, Bih-Show; Ali, M Ajmal; Hatamleh, A A; Al-Hemaid, Fahad M A

    2018-03-15

    Recently, the multiferroic material has fabulous attention in numerous applications owing to its excellent electronic conductivity, unique mechanical property, and higher electrocatalytic activity, etc. In this paper, we reported that the synthesis of bismuth ferrite (BiFeO 3 ) nanosheets integrated functionalized carbon nanofiber (BiFeO 3 NS/F-CNF) nanocomposite using a simple hydrothermal technique. Herein, the structural changes and crystalline property of prepared BiFeO 3 NS/F-CNF nanocomposite were characterized using Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). From this detailed structural evolution, the formation of nanosheets like BiFeO 3 and its nanocomposite with F-CNF were scrutinized and reported. Furthermore, the as-prepared BiFeO 3 NS/F-CNF nanocomposite modified glassy carbon electrode (GCE) was applied for electrochemical detection of catechol (CC). As expected, BiFeO 3 NS/F-CNF/GCE shows excellent electrocatalytic activity as well as 3.44 (F-CNF/GCE) and 7.92 (BiFeO 3 NS/GCE) fold higher electrochemical redox response for CC sensing. Moreover, the proposed sensor displays a wide linear range from 0.003 to 78.02 µM with a very low detection limit of 0.0015 µM. In addition, we have validated the real-time application of our developed CC sensor in different water samples. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Concatenation of electrochemical grafting with chemical or electrochemical modification for preparing electrodes with specific surface functionality

    International Nuclear Information System (INIS)

    Verma, Pallavi; Maire, Pascal; Novak, Petr

    2011-01-01

    Surface modified electrodes are used in electro-analysis, electro-catalysis, sensors, biomedical applications, etc. and could also be used in batteries. The properties of modified electrodes are determined by the surface functionality. Therefore, the steps involved in the surface modification of the electrodes to obtain specific functionality are of prime importance. We illustrate here bridging of two routes of surface modifications namely electrochemical grafting, and chemical or electrochemical reduction. First, by electrochemical grafting an organic moiety is covalently immobilized on the surface. Then, either by chemical or by electrochemical route the terminal functional group of the grafted moiety is transformed. Using the former route we prepared lithium alkyl carbonate (-O(CH 2 ) 3 OCO 2 Li) modified carbon with potential applications in batteries, and employing the latter we prepared phenyl hydroxyl amine (-C 6 H 4 NHOH) modified carbon which may find application in biosensors. Benzyl alcohol (-C 6 H 4 CH 2 OH) modified carbon was prepared by both chemical as well as electrochemical route. We report combinations of conjugating the two steps of surface modifications and show how the optimal route of terminal functional group modification depends on the chemical nature of the moiety attached to the surface in the electrochemical grafting step.

  5. Concatenation of electrochemical grafting with chemical or electrochemical modification for preparing electrodes with specific surface functionality

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Pallavi; Maire, Pascal [Paul Scherrer Institut, Electrochemistry Laboratory, Section Electrochemical Energy Storage, CH-5232 Villigen PSI (Switzerland); Novak, Petr, E-mail: petr.novak@psi.c [Paul Scherrer Institut, Electrochemistry Laboratory, Section Electrochemical Energy Storage, CH-5232 Villigen PSI (Switzerland)

    2011-04-01

    Surface modified electrodes are used in electro-analysis, electro-catalysis, sensors, biomedical applications, etc. and could also be used in batteries. The properties of modified electrodes are determined by the surface functionality. Therefore, the steps involved in the surface modification of the electrodes to obtain specific functionality are of prime importance. We illustrate here bridging of two routes of surface modifications namely electrochemical grafting, and chemical or electrochemical reduction. First, by electrochemical grafting an organic moiety is covalently immobilized on the surface. Then, either by chemical or by electrochemical route the terminal functional group of the grafted moiety is transformed. Using the former route we prepared lithium alkyl carbonate (-O(CH{sub 2}){sub 3}OCO{sub 2}Li) modified carbon with potential applications in batteries, and employing the latter we prepared phenyl hydroxyl amine (-C{sub 6}H{sub 4}NHOH) modified carbon which may find application in biosensors. Benzyl alcohol (-C{sub 6}H{sub 4}CH{sub 2}OH) modified carbon was prepared by both chemical as well as electrochemical route. We report combinations of conjugating the two steps of surface modifications and show how the optimal route of terminal functional group modification depends on the chemical nature of the moiety attached to the surface in the electrochemical grafting step.

  6. A review on the electrochemical applications of room temperature ionic liquids in nuclear fuel cycle

    International Nuclear Information System (INIS)

    Venkatesan, K.A.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2009-01-01

    A mini review on the electrochemical applications of room temperature ionic liquids (RTIL) in nuclear fuel cycle is presented. It is shown that how the fascinating properties of RTIL can be tuned to deliver desirable application in aqueous and non-aqueous reprocessing and in nuclear waste management. (author)

  7. Air Force electrochemical power research and technology program for space applications

    Science.gov (United States)

    Allen, Douglas

    1987-01-01

    An overview is presented of the existing Air Force electrochemical power, battery, and fuel cell programs for space application. Present thrusts are described along with anticipated technology availability dates. Critical problems to be solved before system applications occur are highlighted. Areas of needed performance improvement of batteries and fuel cells presently used are outlined including target dates for key demonstrations of advanced technology. Anticipated performance and current schedules for present technology programs are reviewed. Programs that support conventional military satellite power systems and special high power applications are reviewed. Battery types include bipolar lead-acid, nickel-cadmium, silver-zinc, nickel-hydrogen, sodium-sulfur, and some candidate advanced couples. Fuel cells for pulsed and transportation power applications are discussed as are some candidate advanced regenerative concepts.

  8. Electrochemical energy storage systems for solar thermal applications

    Science.gov (United States)

    Krauthamer, S.; Frank, H.

    1980-01-01

    Existing and advanced electrochemical storage and inversion/conversion systems that may be used with terrestrial solar-thermal power systems are evaluated. The status, cost and performance of existing storage systems are assessed, and the cost, performance, and availability of advanced systems are projected. A prime consideration is the cost of delivered energy from plants utilizing electrochemical storage. Results indicate that the five most attractive electrochemical storage systems are the: iron-chromium redox (NASA LeRC), zinc-bromine (Exxon), sodium-sulfur (Ford), sodium-sulfur (Dow), and zinc-chlorine (EDA).

  9. Simultaneous Voltammetric Determination of Acetaminophen and Isoniazid (Hepatotoxicity-Related Drugs) Utilizing Bismuth Oxide Nanorod Modified Screen-Printed Electrochemical Sensing Platforms.

    Science.gov (United States)

    Mahmoud, Bahaa G; Khairy, Mohamed; Rashwan, Farouk A; Banks, Craig E

    2017-02-07

    To overcome the recent outbreaks of hepatotoxicity-related drugs, a new analytical tool for the continuously determination of these drugs in human fluids is required. Electrochemical-based analytical methods offer an effective, rapid, and simple tool for on-site determination of various organic and inorganic species. However, the design of a sensitive, selective, stable, and reproducible sensor is still a major challenge. In the present manuscript, a facile, one-pot hydrothermal synthesis of bismuth oxide (Bi 2 O 2.33 ) nanostructures (nanorods) was developed. These BiO nanorods were cast onto mass disposable graphite screen-printed electrodes (BiO-SPEs), allowing the ultrasensitive determination of acetaminophen (APAP) in the presence of its common interference isoniazid (INH), which are both found in drug samples. The simultaneous electroanalytical sensing using BiO-SPEs exhibited strong electrocatalytic activity toward the sensing of APAP and INH with an enhanced analytical signal (voltammetric peak) over that achievable at unmodified (bare) SPEs. The electroanalytical sensing of APAP and INH are possible with accessible linear ranges from 0.5 to 1250 μM and 5 to 1760 μM with limits of detection (3σ) of 30 nM and 1.85 μM, respectively. The stability, reproducibility, and repeatability of BiO-SPE were also investigated. The BiO-SPEs were evaluated toward the sensing of APAP and INH in human serum, urine, saliva, and tablet samples. The results presented in this paper demonstrate that BiO-SPEs sensing platforms provide a potential candidate for the accurate determination of APAP and INH within human fluids and pharmaceutical formulations.

  10. Advanced Electrochemical Machining (ECM) for tungsten surface micro-structuring in blanket applications

    International Nuclear Information System (INIS)

    Holstein, Nils; Krauss, Wolfgang; Konys, Jürgen; Heuer, Simon; Weber, Thomas

    2016-01-01

    Highlights: • Electrochemical Machining is an appropriate tool for tungsten shaping. • Progress in shaping achieved by combination of ECM with advanced micro-lithography. • Application in First Wall for connection of plasma facing material to breeder blanket. • Successful development of adhesion promotors by ECM for plasma spraying interlayers. • Microstructure electrochemical manufacturing of tungsten in sizes of 100 μm achieved. - Abstract: Plasma facing components for fusion applications must have to exhibit long-term stability under extreme physical conditions, and therefore any material imperfections caused by mechanical and/or thermal stresses in the shaping processes cannot be tolerated due to a high risk of possible technical failures under fusion conditions. To avoid such defects, the method of Electrochemical Machining (ECM) enables a complete defect-free processing of removal of tungsten material during the desired shaping, also for high penetration depths. Furthermore, supported by lithographic mask pretreatment, three-dimensional distinct geometric structures can be positive-imaged via the directional galvanic dissolution applying M-ECM process into the tungsten bulk material. New required applications for tungsten components, e.g. as adhesion promotors in W-surfaces to enable sure grip and bonding of thick plasma-spraying layers for blanket components, will define the way of further miniaturization of well-established millimeter dimensioned M-ECM shaping processes to dimensions of 100 μm and furthermore down to 50 μm. Besides current M-ECM limits the article describes inevitable needs of further developments for mask resists, mask materials and the resulting ECM parameters, to reach the needed accuracy in tungsten microstructure. The achieved progress and observed correlations of processing parameters will be manifested by produced demonstrators made by the new “μM”-ECM process.

  11. Advanced Electrochemical Machining (ECM) for tungsten surface micro-structuring in blanket applications

    Energy Technology Data Exchange (ETDEWEB)

    Holstein, Nils, E-mail: nils.holstein@kit.edu [Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Baden-Württemberg (Germany); Krauss, Wolfgang; Konys, Jürgen [Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Baden-Württemberg (Germany); Heuer, Simon; Weber, Thomas [Research Center Jülich, Institute of Energy- and Climate Research – Plasma Physics (IEK-4), D-52425 Jülich (Germany)

    2016-11-01

    Highlights: • Electrochemical Machining is an appropriate tool for tungsten shaping. • Progress in shaping achieved by combination of ECM with advanced micro-lithography. • Application in First Wall for connection of plasma facing material to breeder blanket. • Successful development of adhesion promotors by ECM for plasma spraying interlayers. • Microstructure electrochemical manufacturing of tungsten in sizes of 100 μm achieved. - Abstract: Plasma facing components for fusion applications must have to exhibit long-term stability under extreme physical conditions, and therefore any material imperfections caused by mechanical and/or thermal stresses in the shaping processes cannot be tolerated due to a high risk of possible technical failures under fusion conditions. To avoid such defects, the method of Electrochemical Machining (ECM) enables a complete defect-free processing of removal of tungsten material during the desired shaping, also for high penetration depths. Furthermore, supported by lithographic mask pretreatment, three-dimensional distinct geometric structures can be positive-imaged via the directional galvanic dissolution applying M-ECM process into the tungsten bulk material. New required applications for tungsten components, e.g. as adhesion promotors in W-surfaces to enable sure grip and bonding of thick plasma-spraying layers for blanket components, will define the way of further miniaturization of well-established millimeter dimensioned M-ECM shaping processes to dimensions of 100 μm and furthermore down to 50 μm. Besides current M-ECM limits the article describes inevitable needs of further developments for mask resists, mask materials and the resulting ECM parameters, to reach the needed accuracy in tungsten microstructure. The achieved progress and observed correlations of processing parameters will be manifested by produced demonstrators made by the new “μM”-ECM process.

  12. Sensitive electrochemical sensing for polycyclic aromatic amines based on a novel core–shell multiwalled carbon nanotubes@ graphene oxide nanoribbons heterostructure

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Gangbing, E-mail: zhgb1030@ujs.edu.cn [School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013 (China); Yi, Yinhui; Han, Zhixiang [School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013 (China); Wang, Kun [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Wu, Xiangyang, E-mail: wuxy@ujs.edu.cn [School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2014-10-03

    Highlights: • A core–shell heterostructure MWCNTs@GONRs was produced from unzipping MWCNTs. • A new electrochemical sensor for PAAs was developed based on MWCNTs@GONRs hybrids. • The sensor shows good analytical performance for PAAs detection. - Abstract: Being awfully harmful to the environment and human health, the qualitative and quantitative determinations of polycyclic aromatic amines (PAAs) are of great significance. In this paper, a novel core–shell heterostructure of multiwalled carbon nanotubes (MWCNTs) as the core and graphene oxide nanoribbons (GONRs) as the shell (MWCNTs@GONRs) was produced from longitudinal partially unzipping of MWCNTs side walls using a simple wet chemical strategy and applied for electrochemical determination of three kinds of PAAs (1-aminopyrene (1-AP), 1-aminonaphthalene and 3,3′-diaminobiphenyl). Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis and electrochemical methods were used to characterize the as-prepared MWCNTs@GONRs. Due to the synergistic effects from MWCNTs and GONRs, the oxidation currents of PAAs at the MWCNTs@GONRs modified glassy carbon (GC) electrode are much higher than that at the MWCNTs/GC, graphene/GC and bare GC electrodes. 1-AP was used as the representative analyte to demonstrate the sensing performance of the MWCNTs@GONRs/GC electrode, and the proposed modified electrode has a linear response range of 8.0–500.0 nM with a detection limit of 1.5 nM towards 1-AP.

  13. Sensitive electrochemical sensing for polycyclic aromatic amines based on a novel core–shell multiwalled carbon nanotubes@ graphene oxide nanoribbons heterostructure

    International Nuclear Information System (INIS)

    Zhu, Gangbing; Yi, Yinhui; Han, Zhixiang; Wang, Kun; Wu, Xiangyang

    2014-01-01

    Highlights: • A core–shell heterostructure MWCNTs@GONRs was produced from unzipping MWCNTs. • A new electrochemical sensor for PAAs was developed based on MWCNTs@GONRs hybrids. • The sensor shows good analytical performance for PAAs detection. - Abstract: Being awfully harmful to the environment and human health, the qualitative and quantitative determinations of polycyclic aromatic amines (PAAs) are of great significance. In this paper, a novel core–shell heterostructure of multiwalled carbon nanotubes (MWCNTs) as the core and graphene oxide nanoribbons (GONRs) as the shell (MWCNTs@GONRs) was produced from longitudinal partially unzipping of MWCNTs side walls using a simple wet chemical strategy and applied for electrochemical determination of three kinds of PAAs (1-aminopyrene (1-AP), 1-aminonaphthalene and 3,3′-diaminobiphenyl). Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis and electrochemical methods were used to characterize the as-prepared MWCNTs@GONRs. Due to the synergistic effects from MWCNTs and GONRs, the oxidation currents of PAAs at the MWCNTs@GONRs modified glassy carbon (GC) electrode are much higher than that at the MWCNTs/GC, graphene/GC and bare GC electrodes. 1-AP was used as the representative analyte to demonstrate the sensing performance of the MWCNTs@GONRs/GC electrode, and the proposed modified electrode has a linear response range of 8.0–500.0 nM with a detection limit of 1.5 nM towards 1-AP

  14. Remote sensing sensors and applications in environmental resources mapping and modeling

    Science.gov (United States)

    Melesse, Assefa M.; Weng, Qihao; Thenkabail, Prasad S.; Senay, Gabriel B.

    2007-01-01

    The history of remote sensing and development of different sensors for environmental and natural resources mapping and data acquisition is reviewed and reported. Application examples in urban studies, hydrological modeling such as land-cover and floodplain mapping, fractional vegetation cover and impervious surface area mapping, surface energy flux and micro-topography correlation studies is discussed. The review also discusses the use of remotely sensed-based rainfall and potential evapotranspiration for estimating crop water requirement satisfaction index and hence provides early warning information for growers. The review is not an exhaustive application of the remote sensing techniques rather a summary of some important applications in environmental studies and modeling.

  15. Imparting improvements in electrochemical sensors: evaluation of different carbon blacks that give rise to significant improvement in the performance of electroanalytical sensing platforms

    International Nuclear Information System (INIS)

    Vicentini, Fernando Campanhã; Ravanini, Amanda E.; Figueiredo-Filho, Luiz C.S.; Iniesta, Jesús; Banks, Craig E.; Fatibello-Filho, Orlando

    2015-01-01

    Three different carbon black materials have been evaluated as a potential modifier, however, only one demonstrated an improvement in the electrochemical properties. The carbon black structures were characterised with SEM, XPS and Raman spectroscopy and found to be very similar to that of amorphous graphitic materials. The modifications utilised were constructed by three different strategies (using ultrapure water, chitosan and dihexadecylphosphate). The fabricated sensors are electrochemically characterised using N,N,N',N'-tetramethyl-para-phenylenediamine and both inner-sphere and outer-sphere redox probes, namely potassium ferrocyanide(II) and hexaammineruthenium(III) chloride, in addition to the biologically relevant and electroactive analytes, dopamine (DA) and acetaminophen (AP). Comparisons are made with an edge-plane pyrolytic graphite and glassy-carbon electrode and the benefits of carbon black implemented as a modifier for sensors within electrochemistry are explored, as well as the characterisation of their electroanalytical performances. We reveal significant improvements in the electrochemical performance (excellent sensitivity, faster heterogeneous electron transfer rate (HET)) over that of a bare glassy-carbon and edge-plane pyrolytic graphite electrode and thus suggest that there are substantial advantages of using carbon black as modifier in the fabrication of electrochemical based sensors. Such work is highly important and informative for those working in the field of electroanalysis where electrochemistry can provide portable, rapid, reliable and accurate sensing protocols (bringing the laboratory into the field), with particular relevance to those searching for new electrode materials

  16. 2nd International MATHEON Conference on Compressed Sensing and its Applications

    CERN Document Server

    Caire, Giuseppe; Calderbank, Robert; März, Maximilian; Kutyniok, Gitta; Mathar, Rudolf

    2017-01-01

    This contributed volume contains articles written by the plenary and invited speakers from the second international MATHEON Workshop 2015 that focus on applications of compressed sensing. Article authors address their techniques for solving the problems of compressed sensing, as well as connections to related areas like detecting community-like structures in graphs, curbatures on Grassmanians, and randomized tensor train singular value decompositions. Some of the novel applications covered include dimensionality reduction, information theory, random matrices, sparse approximation, and sparse recovery.  This book is aimed at both graduate students and researchers in the areas of applied mathematics, computer science, and engineering, as well as other applied scientists exploring the potential applications for the novel methodology of compressed sensing. An introduction to the subject of compressed sensing is also provided for researchers interested in the field who are not as familiar with it. .

  17. An electrochemical approach: Switching Structures of rare earth metal Praseodymium hexacyanoferrate and its application to sulfite sensor in Red Wine

    International Nuclear Information System (INIS)

    Devadas, Balamurugan; Sivakumar, Mani; Chen, Shen Ming; Cheemalapati, Srikanth

    2015-01-01

    Graphical abstract: Nucleation and growth of PrHCF and its application to sulfite oxidation in wine samples. - Highlights: • Electrochemical synthesis of PrHCF. • Switching structures of PrHCF. • Sulfite electrochemical sensor. • Wide linear range and low limit of detection. • Real sample application. - Abstract: Herein, we report a shape-controlled preparation of Praseodymium hexacyanoferrate (PrHCF) using a simple electrochemical technique. The electrochemically fabricated PrHCF modified glassy carbon electrodes (GCE) shows an excellent electrocatalytic activity towards sulfite oxidation. The morphology of PrHCF particles were controlled by carefully changing various synthesis conditions including electrochemical technique (cyclic voltammetry, amperometry and chemical), cations in the supporting electrolyte (K + , Na + , Li + and H + ), deposition cycles, molar ratio of precursors, and applied potential (-.2,0 and 0.2 V). The morphologies of the PrHCF was elucidated using scanning electron microscopy (SEM). The as-synthesized PrHCF was characterized using X-ray diffraction pattern (XRD), Infra-red (IR) and energy dispersive X-ray spectroscopy (EDX). The electrochemical oxidation of sulfite on PrHCF modified GCE was investigated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The sensitivity of the as-developed sulfite sensor was determined to be 0.036 μA μM −1 cm −2 . The low limit of detection was determined to be 2.15 μM. The real time application of PrHCF modified GCE was confirmed through the determination of sulfite from red wine and tap water samples

  18. Carbon Nanomaterials Based Electrochemical Sensors/Biosensors for the Sensitive Detection of Pharmaceutical and Biological Compounds

    Directory of Open Access Journals (Sweden)

    Bal-Ram Adhikari

    2015-09-01

    Full Text Available Electrochemical sensors and biosensors have attracted considerable attention for the sensitive detection of a variety of biological and pharmaceutical compounds. Since the discovery of carbon-based nanomaterials, including carbon nanotubes, C60 and graphene, they have garnered tremendous interest for their potential in the design of high-performance electrochemical sensor platforms due to their exceptional thermal, mechanical, electronic, and catalytic properties. Carbon nanomaterial-based electrochemical sensors have been employed for the detection of various analytes with rapid electron transfer kinetics. This feature article focuses on the recent design and use of carbon nanomaterials, primarily single-walled carbon nanotubes (SWCNTs, reduced graphene oxide (rGO, SWCNTs-rGO, Au nanoparticle-rGO nanocomposites, and buckypaper as sensing materials for the electrochemical detection of some representative biological and pharmaceutical compounds such as methylglyoxal, acetaminophen, valacyclovir, β-nicotinamide adenine dinucleotide hydrate (NADH, and glucose. Furthermore, the electrochemical performance of SWCNTs, rGO, and SWCNT-rGO for the detection of acetaminophen and valacyclovir was comparatively studied, revealing that SWCNT-rGO nanocomposites possess excellent electrocatalytic activity in comparison to individual SWCNT and rGO platforms. The sensitive, reliable and rapid analysis of critical disease biomarkers and globally emerging pharmaceutical compounds at carbon nanomaterials based electrochemical sensor platforms may enable an extensive range of applications in preemptive medical diagnostics.

  19. Technology development and application research of remote sensing in uranium geological prospecting

    International Nuclear Information System (INIS)

    Liu Dechang; Dong Xiuzhen; Wang Zitao

    2012-01-01

    From the application, the concept, the theory study and application effect, this article discusses technology development and application research of remote sensing in uranium geological prospecting. The prospecting way from 'information prospecting' to 'theoretical prospecting' to 'simulated prospecting' to 'technology prospecting' with remote sensing is provided and achieved significant prospecting effect. (authors)

  20. Ultra-sensitive detection of ibuprofen (IBP) by electrochemical aptasensor using the dendrimer-quantum dot (Den-QD) bioconjugate as an immobilization platform with special features

    Energy Technology Data Exchange (ETDEWEB)

    Roushani, Mahmoud, E-mail: m.roushani@ilam.ac.ir; Shahdost-fard, Faezeh

    2017-06-01

    This study describes a high-performance electrochemical aptasensor which is employed to detect Ibuprofen (IBP) as a painkiller drug by using a novel platform as an integrated sensing interface. In order to make the aptasensor, the Den-QD bioconjugate was immobilized on the surface of a GC electrode and followed the Apt was incubated on this surface. The incubation of the IBP on the aptasensor surface and the formation of the Apt/IBP complex, led to a hindered electron transfer reaction on the sensing surface, which decreased the peak current of the redox probe. Under the optimum condition, the assay had two dynamic ranges with a detection limit down to 333 fM. The developed aptasensor reliably detects IBP in a real sample. Our results demonstrated that the proposed strategy has many advantages and the Den-QD bioconjugate may become a promising nanocomposite for the electrochemical sensing applications. - Highlights: • Fabrication of an ultrasensitive electrochemical nanotool based on target-including conformational switching of an Apt. • The covalent attachment of a 5'-NH2-3'-AgNPs terminated Apt on the surface of a GCE electrode with CdTe QDs. • The use of CdTe QDs as a platform and the elimination of antibodies or enzymes are the advantages of this aptasensor.

  1. Application of Nanomaterials in Production of Self-Sensing Concretes: Contemporary Developments and Prospects

    OpenAIRE

    Horszczaruk E.; Sikora P.; Łukowski P.

    2016-01-01

    In the recent years structural health monitoring (SHM) has gathered spectacular attention in civil engineering applications. Application of such composites enable to improve the safety and performance of structures. Recent advances in nanotechnology have led to development of new family of sensors - self-sensing materials. These materials enable to create the so-called “smart concrete” exhibiting self-sensing ability. Application of self-sensing materials in cement-based materials enables to ...

  2. Six-Port Based Interferometry for Precise Radar and Sensing Applications

    Directory of Open Access Journals (Sweden)

    Alexander Koelpin

    2016-09-01

    Full Text Available Microwave technology plays a more important role in modern industrial sensing applications. Pushed by the significant progress in monolithic microwave integrated circuit technology over the past decades, complex sensing systems operating in the microwave and even millimeter-wave range are available for reasonable costs combined with exquisite performance. In the context of industrial sensing, this stimulates new approaches for metrology based on microwave technology. An old measurement principle nearly forgotten over the years has recently gained more and more attention in both academia and industry: the six-port interferometer. This paper reviews the basic concept, investigates promising applications in remote, as well as contact-based sensing and compares the system with state-of-the-art metrology. The significant advantages will be discussed just as the limitations of the six-port architecture. Particular attention will be paid to impairment effects and non-ideal behavior, as well as compensation and linearization concepts. It will be shown that in application fields, like remote distance sensing, precise alignment measurements, as well as interferometrically-evaluated mechanical strain analysis, the six-port architecture delivers extraordinary measurement results combined with high measurement data update rates for reasonable system costs. This makes the six-port architecture a promising candidate for industrial metrology.

  3. Host-Guest Recognition-Assisted Electrochemical Release: Its Reusable Sensing Application Based on DNA Cross Configuration-Fueled Target Cycling and Strand Displacement Reaction Amplification.

    Science.gov (United States)

    Chang, Yuanyuan; Zhuo, Ying; Chai, Yaqin; Yuan, Ruo

    2017-08-15

    In this work, an elegantly designed host-guest recognition-assisted electrochemical release was established and applied in a reusable electrochemical biosensor for the detection of microRNA-182-5p (miRNA-182-5p), a prostate cancer biomarker in prostate cancer, based on the DNA cross configuration-fueled target cycling and strand displacement reaction (SDR) amplification. With such a design, the single target miRNA input could be converted to large numbers of single-stranded DNA (S1-Trp and S2-Trp) output, which could be trapped by cucurbit[8]uril methyl viologen (CB-8-MV 2+ ) based on the host-guest recognition, significantly enhancing the sensitivity for miRNA detection. Moreover, the nucleic acids products obtained from the process of cycling amplification could be utilized sufficiently, avoiding the waste and saving the experiment cost. Impressively, by resetting a settled voltage, the proposed biosensor could release S1-Trp and S2-Trp from the electrode surface, attributing that the guest ion methyl viologen (MV 2+ ) was reduced to MV +· under this settled voltage and formed a more-stable CB-8-MV +· -MV +· complex. Once O 2 was introduced in this system, MV +· could be oxidized to MV 2+ , generating the complex of CB-8-MV 2+ for capturing S1-Trp and S2-Trp again in only 5 min. As a result, the simple and fast regeneration of biosensor for target detection was realized on the base of electrochemical redox-driven assembly and release, overcoming the challenges of time-consuming, burdensome operations and expensive experimental cost in traditional reusable biosensors and updating the construction method for a reusable bisensor. Furthermore, the biosensor could be reused for more than 10 times with a regeneration rate of 93.20%-102.24%. After all, the conception of this work provides a novel thought for the construction of effective reusable biosensor to detect miRNA and other biomarkers and has great potential application in the area requiring the release of

  4. Highly Efficient Laser Scribed Graphene Electrodes for On-Chip Electrochemical Sensing Applications

    KAUST Repository

    Nayak, Pranati

    2016-08-11

    This study reports the fabrication of flexible electrochemical sensors using a direct-write laser scribing process that transforms commercial polyimide sheet into graphitic carbon with self-standing porous 3D morphology, and abundant edge planes. The heterogeneous electron transfer rate (k0) of the laser scribed graphene (LSG) electrodes for both inner-sphere and outer-sphere redox mediators, ferrocyanide ([Fe(CN)6]4-) and hexaammineruthenium ([Ru(NH3)6]3+) are estimated to be 0.1150 and 0.0868 cm s-1, respectively. These values are significantly higher than those for similar carbon based materials, which this study ascribes to the binder free 3D porous network of LSG with enriched edge plane sites. Further, k0 is enhanced up to 0.2823 and 0.2312 cm s-1 for inner and outer-sphere redox mediators by selective anchoring of Pt nanoparticles over LSG. The LSG electrodes exhibit significantly improved electrocatalytic activity toward oxidation of ascorbic acid (AA), dopamine (DA), and uric acid (UA). Consequently, the detection of these biomarkers is achieved with high sensitivity of 237.76 and 250.69 μA mm-1 cm-2 (AA), 2259.9 and 6995.6 μA mm-1 cm-2 (DA) and 5405 and 8289 μA mm-1 cm-2 (UA) for LSG and Pt/LSG electrodes, respectively, in a wide concentration range. These results outperform previously reported 2D/3D graphene based electrodes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Carbon nanotubes--electronic/electrochemical properties and application for nanoelectronics and photonics.

    Science.gov (United States)

    Sgobba, Vito; Guldi, Dirk M

    2009-01-01

    The fundamental chemical, redox, electrochemical, photoelectrochemical, optical and optoelectronic features of carbon nanotubes are surveyed with particular emphasis on the most relevant applications as electron donor/electron acceptor or as electron conductor/hole conductor materials, in solutions and in the solid state. Methods that aim at p- and n-doping as a means to favor hole or electron injection/transport are covered as well (critical review, 208 references).

  6. Target-induced formation of gold amalgamation on DNA-based sensing platform for electrochemical monitoring of mercury ion coupling with cycling signal amplification strategy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jinfeng; Tang, Juan; Zhou, Jun; Zhang, Lan; Chen, Guonan; Tang, Dianping, E-mail: dianping.tang@fzu.edu.cn

    2014-01-31

    Graphical abstract: -- Highlights: •We report a new electrochemical sensing protocol for the detection of mercury ion. •Gold amalgamation on DNA-based sensing platform was used as nanocatalyst. •The signal was amplified by cycling signal amplification strategy. -- Abstract: Heavy metal ion pollution poses severe risks in human health and environmental pollutant, because of the likelihood of bioaccumulation and toxicity. Driven by the requirement to monitor trace-level mercury ion (Hg{sup 2+}), herein we construct a new DNA-based sensor for sensitive electrochemical monitoring of Hg{sup 2+} by coupling target-induced formation of gold amalgamation on DNA-based sensing platform with gold amalgamation-catalyzed cycling signal amplification strategy. The sensor was simply prepared by covalent conjugation of aminated poly-T{sub (25)} oligonucleotide onto the glassy carbon electrode by typical carbodiimide coupling. Upon introduction of target analyte, Hg{sup 2+} ion was intercalated into the DNA polyion complex membrane based on T–Hg{sup 2+}–T coordination chemistry. The chelated Hg{sup 2+} ion could induce the formation of gold amalgamation, which could catalyze the p-nitrophenol with the aid of NaBH{sub 4} and Ru(NH{sub 3}){sub 6}{sup 3+} for cycling signal amplification. Experimental results indicated that the electronic signal of our system increased with the increasing Hg{sup 2+} level in the sample, and has a detection limit of 0.02 nM with a dynamic range of up to 1000 nM Hg{sup 2+}. The strategy afforded exquisite selectivity for Hg{sup 2+} against other environmentally related metal ions. In addition, the methodology was evaluated for the analysis of Hg{sup 2+} in spiked tap-water samples, and the recovery was 87.9–113.8%.

  7. Design and fabrication of nanoelectrodes for applications with scanning electrochemical microscopy

    Science.gov (United States)

    Thakar, Rahul

    strategy to fabricate parylene based carbon electrodes Here, we have developed a unique strategy to obtain carbon based nanoelectrodes from vapor deposition of parylene over pulled glass nanopipettes. With this approach, multiple electrode geometries were constructed and the application of individual geomtery with SECM is demonstrated. In particular, enhanced spatial resolution and electrochemical information were obtained with the use of carbon ring/nanopore electrodes. Practical implications of edge-effects observed with carbon ring/nanopore electrodes is discussed with substrate generation tip collection (SG/TC) SECM Carbon ring/nanopore electrodes have also enabled the use of SECM in conjunction with ion conductance microscopy to alleviate the issue of poor feedback response. This has further helped in deconvolution of electrochemcial and topographical signals. Although, use of carbon nanoelectrodes is discussed with specific applications to electrochemcial microscopy, these probes have wide utility in electroanalytical applications. Initial proof-of-concept experiments along with future directions for this work are presented.

  8. GNSS remote sensing theory, methods and applications

    CERN Document Server

    Jin, Shuanggen; Xie, Feiqin

    2014-01-01

    This book presents the theory and methods of GNSS remote sensing as well as its applications in the atmosphere, oceans, land and hydrology. It contains detailed theory and study cases to help the reader put the material into practice.

  9. Remote Sensing Applications to Water Quality Management in Florida

    Science.gov (United States)

    Lehrter, J. C.; Schaeffer, B. A.; Hagy, J.; Spiering, B.; Barnes, B.; Hu, C.; Le, C.; McEachron, L.; Underwood, L. W.; Ellis, C.; Fisher, B.

    2013-12-01

    Optical datasets from estuarine and coastal systems are increasingly available for remote sensing algorithm development, validation, and application. With validated algorithms, the data streams from satellite sensors can provide unprecedented spatial and temporal data for local and regional coastal water quality management. Our presentation will highlight two recent applications of optical data and remote sensing to water quality decision-making in coastal regions of the state of Florida; (1) informing the development of estuarine and coastal nutrient criteria for the state of Florida and (2) informing the rezoning of the Florida Keys National Marine Sanctuary. These efforts involved building up the underlying science to demonstrate the applicability of satellite data as well as an outreach component to educate decision-makers about the use, utility, and uncertainties of remote sensing data products. Scientific developments included testing existing algorithms and generating new algorithms for water clarity and chlorophylla in case II (CDOM or turbidity dominated) estuarine and coastal waters and demonstrating the accuracy of remote sensing data products in comparison to traditional field based measurements. Including members from decision-making organizations on the research team and interacting with decision-makers early and often in the process were key factors for the success of the outreach efforts and the eventual adoption of satellite data into the data records and analyses used in decision-making. Florida coastal water bodies (black boxes) for which remote sensing imagery were applied to derive numeric nutrient criteria and in situ observations (black dots) used to validate imagery. Florida ocean color applied to development of numeric nutrient criteria

  10. A novel electrochemical sensor based on zirconia/ordered macroporous polyaniline for ultrasensitive detection of pesticides.

    Science.gov (United States)

    Wang, Yonglan; Jin, Jun; Yuan, Caixia; Zhang, Fan; Ma, Linlin; Qin, Dongdong; Shan, Duoliang; Lu, Xiaoquan

    2015-01-21

    A simple and mild strategy was proposed to develop a novel electrochemical sensor based on zirconia/ordered macroporous polyaniline (ZrO2/OMP) and further used for the detection of methyl parathion (MP), one of the organophosphate pesticides (OPPs). Due to the strong affinity of phosphate groups with ZrO2 and the advantages of OMP such as high catalytic activity and good conductivity, the developed sensor showed a limit of detection as low as 2.28 × 10(-10) mol L(-1) (S/N = 3) by square-wave voltammograms, and good selectivity, acceptable reproducibility and stability. Most importantly, this novel sensor was successfully applied to detect MP in real samples of apple and cabbage. It is expected that this method has potential applications in electrochemical sensing platforms with simple, sensitive, selective and fast analysis.

  11. Microfiber-Based Bragg Gratings for Sensing Applications: A Review

    Directory of Open Access Journals (Sweden)

    Jun-Long Kou

    2012-06-01

    Full Text Available Microfiber-based Bragg gratings (MFBGs are an emerging concept in ultra-small optical fiber sensors. They have attracted great attention among researchers in the fiber sensing area because of their large evanescent field and compactness. In this review, the basic techniques for the fabrication of MFBGs are introduced first. Then, the sensing properties and applications of MFBGs are discussed, including measurement of refractive index (RI, temperature, and strain/force. Finally a summary of selected MFBG sensing elements from previous literature are tabulated.

  12. Nanostructured carbon and carbon nanocomposites for electrochemical energy storage applications.

    Science.gov (United States)

    Su, Dang Sheng; Schlögl, Robert

    2010-02-22

    Electrochemical energy storage is one of the important technologies for a sustainable future of our society, in times of energy crisis. Lithium-ion batteries and supercapacitors with their high energy or power densities, portability, and promising cycling life are the cores of future technologies. This Review describes some materials science aspects on nanocarbon-based materials for these applications. Nanostructuring (decreasing dimensions) and nanoarchitecturing (combining or assembling several nanometer-scale building blocks) are landmarks in the development of high-performance electrodes for with long cycle lifes and high safety. Numerous works reviewed herein have shown higher performances for such electrodes, but mostly give diverse values that show no converging tendency towards future development. The lack of knowledge about interface processes and defect dynamics of electrodes, as well as the missing cooperation between material scientists, electrochemists, and battery engineers, are reasons for the currently widespread trial-and-error strategy of experiments. A concerted action between all of these disciplines is a prerequisite for the future development of electrochemical energy storage devices.

  13. Sensor Access to the Cellular Microenvironment Using the Sensing Cell Culture Flask.

    Science.gov (United States)

    Kieninger, Jochen; Tamari, Yaara; Enderle, Barbara; Jobst, Gerhard; Sandvik, Joe A; Pettersen, Erik O; Urban, Gerald A

    2018-04-26

    The Sensing Cell Culture Flask (SCCF) is a cell culture monitoring system accessing the cellular microenvironment in 2D cell culture using electrochemical microsensors. The system is based on microfabricated sensor chips embedded in standard cell culture flasks. Ideally, the sensor chips could be equipped with any electrochemical sensor. Its transparency allows optical inspection of the cells during measurement. The surface of the sensor chip is in-plane with the flask surface allowing undisturbed cell growth on the sensor chip. A custom developed rack system allows easy usage of multiple flasks in parallel within an incubator. The presented data demonstrates the application of the SCCF with brain tumor (T98G) and breast cancer (T-47D) cells. Amperometric oxygen sensors were used to monitor cellular respiration with different incubation conditions. Cellular acidification was accessed with potentiometric pH sensors using electrodeposited iridium oxide films. The system itself provides the foundation for electrochemical monitoring systems in 3D cell culture.

  14. Sensor Access to the Cellular Microenvironment Using the Sensing Cell Culture Flask

    Directory of Open Access Journals (Sweden)

    Jochen Kieninger

    2018-04-01

    Full Text Available The Sensing Cell Culture Flask (SCCF is a cell culture monitoring system accessing the cellular microenvironment in 2D cell culture using electrochemical microsensors. The system is based on microfabricated sensor chips embedded in standard cell culture flasks. Ideally, the sensor chips could be equipped with any electrochemical sensor. Its transparency allows optical inspection of the cells during measurement. The surface of the sensor chip is in-plane with the flask surface allowing undisturbed cell growth on the sensor chip. A custom developed rack system allows easy usage of multiple flasks in parallel within an incubator. The presented data demonstrates the application of the SCCF with brain tumor (T98G and breast cancer (T-47D cells. Amperometric oxygen sensors were used to monitor cellular respiration with different incubation conditions. Cellular acidification was accessed with potentiometric pH sensors using electrodeposited iridium oxide films. The system itself provides the foundation for electrochemical monitoring systems in 3D cell culture.

  15. Carbon Onions: Synthesis and Electrochemical Applications

    Energy Technology Data Exchange (ETDEWEB)

    McDonough, John K. [Drexel Univ., Philadelphia, PA (United States). Dept. of Materials Science and Engineering; Gogotsi, Y. [Drexel Univ., Philadelphia, PA (United States). Dept. of Materials Science and Engineering

    2013-01-01

    Onion-like carbon structures have been synthesized in many ways and large scale production is currently under study. The annealing method can satisfy the need for large scale production, though the ideal spherical shape is unachievable, and the temperature attainable in this method is not sufficient for treating the entire particle. The arc-discharge method provides an alternate pathway toward large scale synthesis. Due to its structure and electrochemical properties, carbon onions can be used as materials for electrochemical double layer capacitors (EDLC) and can be used to store energy across a much wider temperature range, which gives these materials advantages over conventional EDLCs. This and other aspects of carbon onions are discussed in this article.

  16. Preparation of iron-deposited graphite surface for application as cathode material during electrochemical vat-dyeing process

    International Nuclear Information System (INIS)

    Anbu Kulandainathan, M.; Kiruthika, K.; Christopher, G.; Babu, K. Firoz; Muthukumaran, A.; Noel, M.

    2008-01-01

    Iron-deposited graphite surfaces were prepared, characterized and employed as cathode materials for electrochemical vat-dyeing process containing very low concentration of sodium dithionite. The electrodeposition, in presence of ammonium thiocyanate and gelatin or animal glue as binding additives, were found to give finer iron deposits for improved electrochemical dyeing application. The electrodeposits were characterized using scanning electron microscopy, electron-dispersive X-ray spectroscopy and X-ray diffraction methods, before and after electrochemical dyeing process. The electrochemical activity of the iron-deposited graphite electrodes always stored in water seems to depend on the surface-bound Fe 3+ /Fe 2+ redox species. Vat dyes like C.I. Vat Violet 1, C.I. Vat Green 1 and C.I. Vat Blue 4 could be efficiently dyed employing these above electrode materials. The colour intensity and washing fastness of the dyed fabrics were found to be equal with conventionally dyed fabrics. The electrodes could also be reused for the dyeing process

  17. Molecularly imprinted electrochemical sensing interface based on in-situ-polymerization of amino-functionalized ionic liquid for specific recognition of bovine serum albumin.

    Science.gov (United States)

    Wang, Yanying; Han, Miao; Liu, Guishen; Hou, Xiaodong; Huang, Yina; Wu, Kangbing; Li, Chunya

    2015-12-15

    A molecularly imprinted polymer film was in situ polymerized on a carboxyl functionalized multi-walled carbon nanotubes modified glassy carbon electrode surface under room temperature. This technique provides a promising imprinting approach for protein in an aqueous solution using 3-(3-aminopropyl)-1-vinylimidazolium tetrafluoroborate ionic liquid as functional monomer, N, N'-methylenebisacrylamide as crossing linker, ammonium persulfate and N,N,N',N'-tetramethylethylenediamine as initiator, and bovine serum albumin (BSA) as template. The molecularly imprinted polymerized ionic liquid film shows enhanced accessibility, high specificity and sensitivity towards BSA. Electrochemical sensing performance of the imprinted sensor was thoroughly investigated using K3Fe[CN]6/K4Fe[CN]6 as electroactive probes. Under optimal conditions, the current difference before and after specific recognition of BSA was found linearly related to its concentration in the range from 1.50×10(-9) to 1.50×10(-6) mol L(-1). The detection limit was calculated to be 3.91×10(-10) mol L(-1) (S/N=3). The practical application of the imprinted sensor was demonstrated by determining BSA in liquid milk samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Graphene Nanosheets/Poly(3,4-ethylenedioxythiophene) Nanotubes Composite Materials for Electrochemical Biosensing Applications

    International Nuclear Information System (INIS)

    Huang, Tzu-Yen; Kung, Chung-Wei; Wang, Jen-Yuan; Lee, Min-Han; Chen, Lin-Chi; Chu, Chih-Wei; Ho, Kuo-Chuan

    2015-01-01

    Highlights: • Novel composite materials contain 2D rGO nanosheets and 1D PEDOT nanotubes. • 3D nanocomposite film effectively improved the sensitivity for analyte detection. • The rGO/PEDOT NTs film shows good catalytic activities toward hydrazine and H 2 O 2 . • The rGO/PEDOT NTs film also exhibits high selectivity from the interference test. -- Graphical abstract: Display Omitted -- Abstract: In this study, we developed the novel composite materials containing reduced graphene oxide (rGO) nanosheets and poly(3,4-ethylenedioxythiophene) nanotubes (PEDOT NTs) for electrochemical biosensing applications. Transmission electron microscopy, scanning electron microscopy and atomic force microscopy suggested that the rGO nanosheets cover the substrate uniformly, and the PEDOT NTs act as a conducting bridge to connect the rGO sheets. By combining the two materials, it's expected to enhance the conductivity of the film and improve the surface coverage. We applied the rGO/PEDOT NTs composite for electrochemical detection of hydrazine and hydrogen peroxide; noticeable improvements in electrochemical activity and reactivity were observed compared to those of the pristine rGO and PEDOT NTs electrodes. This may be attributed to the better surface coverage of the rGO/PEDOT NTs modified electrode with superior conductivity. Furthermore, interference tests indicate that the rGO/PEDOT NTs composite film exhibits high selectivity toward the analyte. The rGO/PEDOT NTs composite thus provides a potential platform for biosensing applications

  19. Science and Technology Text Mining: Electrochemical Power

    Science.gov (United States)

    2003-07-14

    electrodes) and improvements based on component materials (glassy carbon, carbon fibers, aerogels , thin films). A focal point of electrochemical capacitor...performance of carbon aerogels ; and the fabrication and application of Cu-carbon composite (prepared from sawdust) to electrochemical capacitor electrodes. xi...applications require decreases in size and weight, especially for space, aircraft , and individual soldier or small team applications. For large volumes

  20. Covalent attachment of aptamer onto nanocomposite as a high performance electrochemical sensing platform: Fabrication of an ultra-sensitive ibuprofen electrochemical aptasensor

    Energy Technology Data Exchange (ETDEWEB)

    Roushani, Mahmoud, E-mail: mahmoudroushani@yahoo.com; Shahdost-fard, Faezeh

    2016-11-01

    In the present study, we report a selective electrochemical aptasensor for the ultrasensitive detection of an anti-inflammatory drug, ibuprofen (IBP). The proposed system was achieved by the modification of a glassy carbon electrode (GCE) with multiwalled carbon nanotubes/ionic liquid/chitosan (MWCNTs/IL/Chit) nanocomposite and the covalent immobilization of the IBP specific aptamer (Apt) onto the modified electrode surface followed by methylene blue (MB) intercalated onto the Apt as the electrochemical redox marker. Upon the incubation of the IBP as a target in the proposed aptasensor, the peak current of MB decreases due to the formation of the Apt-IBP complex and the displacement of MB from the immobilized Apt onto the modified electrode surface. The nanocomposite not only increases the electrode surface area and accelerate the electron transfer kinetics but also it provides a highly stable matrix to enhance the loading amount of the Apt DNA sequence. Through differential pulse voltammetry (DPV) experiments, it was found that the proposed aptasensor could detect the IBP with a linear range (70 pM up to 6 μM) and the detection limit (LOD) as low as 20 pM. The results showed that the aptasensor had good sensitivity, stability, reproducibility, and specificity to detect the IBP. The proposed aptasensor was successfully applied for measuring the IBP concentration in real samples. Based on our experiments we can say that the present method proposes new horizons for the development of other aptasensors for diagnostic application in biosensing. - Highlights: • An electrochemical aptasensor is developed for ultrasensitive detection of IBP. • The aptasensor is made by covalent immobilization of aptamer on a modified GCE. • A nanocomposite as a modifier provides a specific surface with high conductivity. • This nanocomposite leads to a high density of the DNA sequence on the GCE surface. • This method proposes new horizons for development other aptasensors for

  1. Covalent attachment of aptamer onto nanocomposite as a high performance electrochemical sensing platform: Fabrication of an ultra-sensitive ibuprofen electrochemical aptasensor

    International Nuclear Information System (INIS)

    Roushani, Mahmoud; Shahdost-fard, Faezeh

    2016-01-01

    In the present study, we report a selective electrochemical aptasensor for the ultrasensitive detection of an anti-inflammatory drug, ibuprofen (IBP). The proposed system was achieved by the modification of a glassy carbon electrode (GCE) with multiwalled carbon nanotubes/ionic liquid/chitosan (MWCNTs/IL/Chit) nanocomposite and the covalent immobilization of the IBP specific aptamer (Apt) onto the modified electrode surface followed by methylene blue (MB) intercalated onto the Apt as the electrochemical redox marker. Upon the incubation of the IBP as a target in the proposed aptasensor, the peak current of MB decreases due to the formation of the Apt-IBP complex and the displacement of MB from the immobilized Apt onto the modified electrode surface. The nanocomposite not only increases the electrode surface area and accelerate the electron transfer kinetics but also it provides a highly stable matrix to enhance the loading amount of the Apt DNA sequence. Through differential pulse voltammetry (DPV) experiments, it was found that the proposed aptasensor could detect the IBP with a linear range (70 pM up to 6 μM) and the detection limit (LOD) as low as 20 pM. The results showed that the aptasensor had good sensitivity, stability, reproducibility, and specificity to detect the IBP. The proposed aptasensor was successfully applied for measuring the IBP concentration in real samples. Based on our experiments we can say that the present method proposes new horizons for the development of other aptasensors for diagnostic application in biosensing. - Highlights: • An electrochemical aptasensor is developed for ultrasensitive detection of IBP. • The aptasensor is made by covalent immobilization of aptamer on a modified GCE. • A nanocomposite as a modifier provides a specific surface with high conductivity. • This nanocomposite leads to a high density of the DNA sequence on the GCE surface. • This method proposes new horizons for development other aptasensors for

  2. A host-guest-recognition-based electrochemical aptasensor for thrombin detection.

    Science.gov (United States)

    Fan, Hao; Li, Hui; Wang, Qingjiang; He, Pingang; Fang, Yuzhi

    2012-05-15

    A sensitive electrochemical aptasensor for thrombin detection is presented based on the host-guest recognition technique. In this sensing protocol, a 15 based thrombin aptamer (ab. TBA) was dually labeled with a thiol at its 3' end and a 4-((4-(dimethylamino)phenyl)azo) benzoic acid (dabcyl) at its 5' end, respectively, which was previously immobilized on one Au electrode surface by AuS bond and used as the thrombin probe during the protein sensing procedure. One special electrochemical marker was prepared by modifying CdS nanoparticle with β-cyclodextrins (ab. CdS-CDs), which employed as electrochemical signal provider and would conjunct with the thrombin probe modified electrode through the host-guest recognition of CDs to dabcyl. In the absence of thrombin, the probe adopted linear structure to conjunct with CdS-CDs. In present of thrombin, the TBA bond with thrombin and transformed into its special G-quarter structure, which forced CdS-CDs into the solution. Therefore, the target-TBA binding event can be sensitively transduced via detecting the electrochemical oxidation current signal of Cd of CdS nanoparticles in the solution. Using this method, as low as 4.6 pM thrombin had been detected. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Carbon nanofiber vs. carbon microparticles as modifiers of glassy carbon and gold electrodes applied in electrochemical sensing of NADH.

    Science.gov (United States)

    Pérez, Briza; Del Valle, Manel; Alegret, Salvador; Merkoçi, Arben

    2007-12-15

    Carbon materials (CMs), such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), and carbon microparticles (CMPs) are used as doping materials for electrochemical sensors. The efficiency of these materials (either before or after acidic treatments) while being used as electrocatalysts in electrochemical sensors is discussed for beta-nicotinamide adenine dinucleotide (NADH) detection using cyclic voltammetry (CV). The sensitivity of the electrodes (glassy carbon (GC) and gold (Au)) modified with both treated and untreated materials have been deeply studied. The response efficiencies of the GC and Au electrodes modified with CNF and CMP, using dimethylformamide (DMF) as dispersing agent are significantly different due to the peculiar physical and chemical characteristics of each doping material. Several differences between the electrocatalytic activities of CMs modified electrodes upon NADH oxidation have been observed. The CNF film promotes better the electron transfer of NADH minimizing the oxidation potential at +0.352 V. Moreover higher currents for the NADH oxidation peak have been observed for these electrodes. The shown differences in the electrochemical reactivities of CNF and CMP modified electrodes should be with interest for future applications in biosensors.

  4. A framework for developing remote sensing applications

    International Nuclear Information System (INIS)

    Ahmad, T.; Hayat, M.F.; Afzal, M.; Asif, H.M.S.; Asif, K.H.

    2014-01-01

    Remote Sensing Application (RSA) is important as one of the critical enabler of e-systems such as e- governments, e-commerce, and e-sciences. In this study, we argued that owning to the specialized needs of RSA such as volatility and interactive nature, a customized Software Engineering (SE) approach should be adapted for their development. Based on this argument we have also identified the shortcomings of the conventional SE approaches and the classical waterfall software development life cycle model. In this study, we have proposed a modification to the classical waterfall software development life cycle model for proposing a customized software development Framework for RSAs. We have identified four (4) different types of changes that can occur to an already developed RS application. The proposed framework was capable to incorporate all four types of changes. Remote Sensing, software engineering, functional requirements, types of changes. (author)

  5. Synthesis and electrochemical properties of MnO2 nanorods/graphene composites for supercapacitor applications

    International Nuclear Information System (INIS)

    Deng, SiXu; Sun, Dan; Wu, ChunHui; Wang, Hao; Liu, JingBing; Sun, YuXiu; Yan, Hui

    2013-01-01

    MnO 2 nanorods/graphene composite materials have been fabricated using a facile hydrothermal method for supercapacitor applications. The prepared composite materials are characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscope (TEM). Electrochemical performances are evaluated using cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectrometry (EIS). It indicates that ratio of MnO 2 nanorods to graphene in composite materials has significant influence on the electrochemical performance of composite electrodes. We have achieved the maximum specific capacitance of 218 F g −1 at the scan rate of 5 mV s −1 in 1 M Na 2 SO 4 aqueous solution. Additionally, MnO 2 nanorods/graphene composite materials exhibit highest energy density of 16 Wh kg −1 at power density of 95 W kg −1 and excellent capacitance retention with no more than 6% capacitance loss after 1000 cycles at the most favorable composites ratio

  6. Estrone specific molecularly imprinted polymeric nanospheres: synthesis, characterization and applications for electrochemical sensor development.

    Science.gov (United States)

    Congur, Gulsah; Senay, Hilal; Turkcan, Ceren; Canavar, Ece; Erdem, Arzum; Akgol, Sinan

    2013-06-28

    The aim of this study is (i) to prepare estrone-imprinted nanospheres (nano-EST-MIPs) and (ii) to integrate them into the electrochemical sensor as a recognition layer. N-methacryloyl-(l)-phenylalanine (MAPA) was chosen as the complexing monomer. Firstly, estrone (EST) was complexed with MAPA and the EST-imprinted poly(2-hyroxyethylmethacrylate-co-N-methacryloyl-(l)-phenylalanine) [EST-imprinted poly(HEMA-MAPA)] nanospheres were synthesized by surfactant- free emulsion polymerization method. The specific surface area of the EST-imprinted poly(HEMA-MAPA) nanospheres was found to be 1275 m2/g with a size of 163.2 nm in diameter. According to the elemental analysis results, the nanospheres contained 95.3 mmole MAPA/g nanosphere. The application of EST specific MIP nanospheres for the development of an electrochemical biosensor was introduced for the first time in our study by using electrochemical impedance spectroscopy (EIS) technique. This nano-MIP based sensor presented a great specificity and selectivity for EST.

  7. Novel Ag@TiO2 nanocomposite synthesized by electrochemically active biofilm for nonenzymatic hydrogen peroxide sensor

    International Nuclear Information System (INIS)

    Khan, Mohammad Mansoob; Ansari, Sajid Ali; Lee, Jintae; Cho, Moo Hwan

    2013-01-01

    A novel nonenzymatic sensor for H 2 O 2 was developed based on an Ag@TiO 2 nanocomposite synthesized using a simple and cost effective approach with an electrochemically active biofilm. The optical, structural, morphological and electrochemical properties of the as-prepared Ag@TiO 2 nanocomposite were examined by UV–vis spectroscopy, X-ray diffraction, transmission electron microscopy and cyclic voltammetry (CV). The Ag@TiO 2 nanocomposite was fabricated on a glassy carbon electrode (GCE) and their electrochemical performance was analyzed by CV, differential pulse voltammetry and electrochemical impedance spectroscopy. The Ag@TiO 2 nanocomposite modified GCE (Ag@TiO 2 /GCE) displayed excellent performance towards H 2 O 2 sensing at − 0.73 V in the linear response range from 0.83 μM to 43.3 μM, within a detection limit and sensitivity of 0.83 μM and ∼ 65.2328 ± 0.01 μAμM −1 cm −2 , respectively. In addition, Ag@TiO 2 /GCE exhibited good operational reproducibility and long term stability. - Graphical abstract: Synthesis of Ag@TiO 2 nanocomposite by electrochemically active biofilm for H 2 O 2 sensing. - Highlights: • Electrochemically active biofilm (EAB) • EAB mediated synthesis of Ag@TiO 2 nanocomposite • Ag@TiO 2 nanocomposite modified glassy carbon electrode • Ag@TiO 2 /GCE for H 2 O 2 sensing • Nonenzymatic sensor for H 2 O 2

  8. Remote sensing science - new concepts and applications

    Energy Technology Data Exchange (ETDEWEB)

    Gerstl, S.A.; Cooke, B.J.; Henderson, B.G.; Love, S.P.; Zardecki, A.

    1996-10-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The science and technology of satellite remote sensing is an emerging interdisciplinary field that is growing rapidly with many global and regional applications requiring quantitative sensing of earth`s surface features as well as its atmosphere from space. It is possible today to resolve structures on the earth`s surface as small as one meter from space. If this high spatial resolution is coupled with high spectral resolution, instant object identification can also be achieved. To interpret these spectral signatures correctly, it is necessary to perform a computational correction on the satellite imagery that removes the distorting effects of the atmosphere. This project studied such new concepts and applied innovative new approaches in remote sensing science.

  9. Engineering the Surface/Interface Structures of Titanium Dioxide Micro and Nano Architectures towards Environmental and Electrochemical Applications

    DEFF Research Database (Denmark)

    Wang, Xiaoliang; Zhao, Yanyan; Mølhave, Kristian

    2017-01-01

    advances in the surface and interface engineering and applications in environmental and electrochemical applications. We analyze the advantages of surface/interface engineered TiO₂ micro and nano structures, and present the principles and growth mechanisms of TiO₂ nanostructures via different strategies...

  10. Electrochemical Sensors for Clinic Analysis

    Directory of Open Access Journals (Sweden)

    Guang Li

    2008-03-01

    Full Text Available Demanded by modern medical diagnosis, advances in microfabrication technology have led to the development of fast, sensitive and selective electrochemical sensors for clinic analysis. This review addresses the principles behind electrochemical sensor design and fabrication, and introduces recent progress in the application of electrochemical sensors to analysis of clinical chemicals such as blood gases, electrolytes, metabolites, DNA and antibodies, including basic and applied research. Miniaturized commercial electrochemical biosensors will form the basis of inexpensive and easy to use devices for acquiring chemical information to bring sophisticated analytical capabilities to the non-specialist and general public alike in the future.

  11. Carbon nanomaterial based electrochemical sensors for biogenic amines

    International Nuclear Information System (INIS)

    Yang, Xiao; He, Xiulan; Li, Fangping; Fei, Junjie; Feng, Bo; Ding, Yonglan

    2013-01-01

    This review describes recent advances in the use of carbon nanomaterials for electroanalytical detection of biogenic amines (BAs). It starts with a short introduction into carbon nanomaterials such as carbon nanotubes, graphene, nanodiamonds, carbon nanofibers, fullerenes, and their composites. Next, electrochemical sensing schemes are discussed for various BAs including dopamine, serotonin, epinephrine, norepinephrine, tyramine, histamine and putrescine. Examples are then given for methods for simultaneous detection of various BAs. Finally, we discuss the current and future challenges of carbon nanomaterial-based electrochemical sensors for BAs. The review contains 175 references. (author)

  12. Electrochemical Sensors Based on Screen-Printed Electrodes: The Use of Phthalocyanine Derivatives for Application in VFA Detection

    Directory of Open Access Journals (Sweden)

    Amadou L. Ndiaye

    2016-09-01

    Full Text Available Here, we report on the use of electrochemical methods for the detection of volatiles fatty acids (VFAs, namely acetic acid. We used tetra-tert-butyl phthalocyanine (PcH2-tBu as the sensing material and investigated its electroanalytical properties by means of cyclic voltammetry (CV and square wave voltammetry (SWV. To realize the electrochemical sensing system, the PcH2-tBu has been dropcast-deposited on carbon (C orgold (Auscreen-printed electrodes (SPEs and characterized by cyclic voltammetry and scanning electron microscopy (SEM. The SEM analysis reveals that the PcH2-tBu forms mainly aggregates on the SPEs. The modified electrodes are used for the detection of acetic acid and present a linear current increase when the acetic acid concentration increases. The Cmodified electrode presents a limit of detection (LOD of 25.77 mM in the range of 100 mM–400 mM, while the Aumodified electrode presents an LOD averaging 40.89 mM in the range of 50 mM–300 mM. When the experiment is realized in a buffered condition, theCmodified electrode presents a lower LOD, which averagesthe 7.76 mM. A pronounced signal decay attributed to an electrode alteration is observed in the case of the gold electrode. This electrode alteration severely affects the coating stability. This alteration is less perceptible in the case of the carbon electrode.

  13. Tunable electronic and magnetism of SrTiO{sub 3}/BiFeO{sub 3} (001) superlattice: For electrochemical applications

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qiang; Sopiha, Kostiantyn; Sobhan, Mushtaq; Anariba, Franklin; Wu, Ping, E-mail: wuping@sutd.edu.sg [Entropic Interface Group (EIG), Engineering Product Development, Singapore University of Technology and Design (SUTD), 8 Somapah Road, Singapore 487372 (Singapore); Ong, Khuong Phuong; Zheng, Jian Wei [Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research - A*Star, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632 (Singapore)

    2016-01-04

    Practical strategy in tuning the conductivity and magnetism of SrTiO{sub 3}/BiFeO{sub 3} (STO/BFO) (001) superlattice is investigated using the first-principles method based on density functional theory. Our calculated results show that both the conductivity and magnetism of this superlattice can be tuned via a control of its interface terminations. The STO layers maintain semiconducting, while the BFO layers demonstrate metallic character. Therefore, the conductivity of STO/BFO is controlled by the BFO layers. Furthermore, a magnetic STO/BFO (001) superlattice can be found in n-type TiO{sub 2}/BiO interface but with heavy electron carriers. The thickness of BFO does not change the electronic structure and character of STO/BFO (001) superlattice. This study provides a fundamental understanding of the chemically turned conductivity and magnetism of BFO thin films, which may further advance electrochemical applications like magnetic-field aided chemical gas sensing, solar cells, and photo-catalytic chemical reactions.

  14. Remote sensing applications for monitoring rangeland vegetation ...

    African Journals Online (AJOL)

    Remote sensing techniques hold considerable promise for the inventory and monitoring of natural resources on rangelands. A significant lack of information concerning basic spectral characteristics of range vegetation and soils has resulted in a lack of rangeland applications. The parameters of interest for range condition ...

  15. Binary CuO/Co3O4 nanofibers for ultrafast and amplified electrochemical sensing of fructose

    International Nuclear Information System (INIS)

    Wang Yang; Wang Wen; Song Wenbo

    2011-01-01

    Highlights: → Binary CuO/Co 3 O 4 nanofiber as active electrode material. → Dramatically enhanced catalytic activity and direct fructose detection. → Significantly lowered overpotential, ultrafast (1 s) and sensitive (18.988 μA mM -1 ) response. - Abstract: Cobalt oxide-doped copper oxide composite nanofibers (CCNFs) were successfully achieved via electrospinning followed by thermal treatment processes and then exploited as active electrode material for direct enzyme-free fructose detection. The morphology and the structure of as-prepared samples were investigated by X-ray diffraction spectrum (XRD) and scanning electron microscopy (SEM). The electrocatalytic activity of CCNFs films towards fructose oxidation and sensing performances were evaluated by conventional electrochemical techniques. Cyclic voltammetry (CV) and chronoamperometry (I-t) revealed the distinctly enhanced sensing properties towards fructose compared to pure copper oxide nanofibers (CNFs), i.e., showing significantly lowered overpotential of 0.30 V, ultrafast (1 s) and ultrasensitive (18.988 μA mM -1 ) current response in a wide linear range of 1.0 x 10 -5 M to 6.0 x 10 -3 M with satisfied reproducibility and stability, which could be ascribed to the synergic catalytic effect of the binary CuO/Co 3 O 4 composite nanofibers and the highly porous three-dimensional network films structure of the CCNFs. In addition, a good selectivity for fructose detection was achieved. Results in this work demonstrated that CCNFs is one of the promising catalytic electrode materials for enzymeless fructose sensor fabrication.

  16. Peptide-based biosensors: From self-assembled interfaces to molecular probes in electrochemical assays.

    Science.gov (United States)

    Puiu, Mihaela; Bala, Camelia

    2018-04-01

    Redox-tagged peptides have emerged as functional materials with multiple applications in the area of sensing and biosensing applications due to their high stability, excellent redox properties and versatility of biomolecular interactions. They allow direct observation of molecular interactions in a wide range of affinity and enzymatic assays and act as electron mediators. Short helical peptides possess the ability to self-assemble in specific configurations with the possibility to develop in highly-ordered, stable 1D, 2D and 3D architectures in a hierarchical controlled manner. We provide here a brief overview of the electrochemical techniques available to study the electron transfer in peptide films with particular interest in developing biosensors with immobilized peptide motifs, for biological and clinical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Building micro and nanosystems with electrochemical discharges

    International Nuclear Information System (INIS)

    Wuethrich, Rolf; Allagui, Anis

    2010-01-01

    Since the discovery of the electrochemical discharge phenomenon by Fizeau and Foucault, several contributions have expanded the wide range of applications associated with this high current density electrochemical process. The complexity of the phenomenon, from the macroscopic to the microscopic scales, led since then to experimental and theoretical studies from different research fields. This contribution reviews the chemical and electrochemical perspectives where a mechanistic model based on results from radiation chemistry of aqueous solutions is proposed. In addition applications to micro-machining and fabrication of nanoparticles are discussed.

  18. Building micro and nanosystems with electrochemical discharges

    Energy Technology Data Exchange (ETDEWEB)

    Wuethrich, Rolf, E-mail: wuthrich@encs.concordia.c [Department of Mechanical and Industrial Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montreal, QC (Canada); Allagui, Anis [Department of Mechanical and Industrial Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montreal, QC (Canada)

    2010-11-30

    Since the discovery of the electrochemical discharge phenomenon by Fizeau and Foucault, several contributions have expanded the wide range of applications associated with this high current density electrochemical process. The complexity of the phenomenon, from the macroscopic to the microscopic scales, led since then to experimental and theoretical studies from different research fields. This contribution reviews the chemical and electrochemical perspectives where a mechanistic model based on results from radiation chemistry of aqueous solutions is proposed. In addition applications to micro-machining and fabrication of nanoparticles are discussed.

  19. Electrochemical Detection in Stacked Paper Networks.

    Science.gov (United States)

    Liu, Xiyuan; Lillehoj, Peter B

    2015-08-01

    Paper-based electrochemical biosensors are a promising technology that enables rapid, quantitative measurements on an inexpensive platform. However, the control of liquids in paper networks is generally limited to a single sample delivery step. Here, we propose a simple method to automate the loading and delivery of liquid samples to sensing electrodes on paper networks by stacking multiple layers of paper. Using these stacked paper devices (SPDs), we demonstrate a unique strategy to fully immerse planar electrodes by aqueous liquids via capillary flow. Amperometric measurements of xanthine oxidase revealed that electrochemical sensors on four-layer SPDs generated detection signals up to 75% higher compared with those on single-layer paper devices. Furthermore, measurements could be performed with minimal user involvement and completed within 30 min. Due to its simplicity, enhanced automation, and capability for quantitative measurements, stacked paper electrochemical biosensors can be useful tools for point-of-care testing in resource-limited settings. © 2015 Society for Laboratory Automation and Screening.

  20. 3D-printing technologies for electrochemical applications.

    Science.gov (United States)

    Ambrosi, Adriano; Pumera, Martin

    2016-05-21

    Since its conception during the 80s, 3D-printing, also known as additive manufacturing, has been receiving unprecedented levels of attention and interest from industry and research laboratories. This is in addition to end users, who have benefited from the pervasiveness of desktop-size and relatively cheap printing machines available. 3D-printing enables almost infinite possibilities for rapid prototyping. Therefore, it has been considered for applications in numerous research fields, ranging from mechanical engineering, medicine, and materials science to chemistry. Electrochemistry is another branch of science that can certainly benefit from 3D-printing technologies, paving the way for the design and fabrication of cheaper, higher performing, and ubiquitously available electrochemical devices. Here, we aim to provide a general overview of the most commonly available 3D-printing methods along with a review of recent electrochemistry related studies adopting 3D-printing as a possible rapid prototyping fabrication tool.

  1. An Update of NASA Public Health Applications Projects using Remote Sensing Data

    Science.gov (United States)

    Estes, Sue M.; Haynes, J. A.

    2009-01-01

    Satellite earth observations present a unique vantage point of the earth s environment from space which offers a wealth of health applications for the imaginative investigator. The session will present research results of the remote sensing environmental observations of earth and health applications. This session will an overview of many of the NASA public health applications using Remote Sensing Data and will also discuss opportunities to become a research collaborator with NASA.

  2. Recent Advances in Metal Chalcogenides (MX; X = S, Se) Nanostructures for Electrochemical Supercapacitor Applications: A Brief Review

    Science.gov (United States)

    Theerthagiri, Jayaraman; Durai, Govindarajan; Rana, Abu ul Hassan Sarwar; Sangeetha, Kirubanandam; Kuppusami, Parasuraman; Kim, Hyun-Seok

    2018-01-01

    Supercapacitors (SCs) have received a great deal of attention and play an important role for future self-powered devices, mainly owing to their higher power density. Among all types of electrical energy storage devices, electrochemical supercapacitors are considered to be the most promising because of their superior performance characteristics, including short charging time, high power density, safety, easy fabrication procedures, and long operational life. An SC consists of two foremost components, namely electrode materials, and electrolyte. The selection of appropriate electrode materials with rational nanostructured designs has resulted in improved electrochemical properties for high performance and has reduced the cost of SCs. In this review, we mainly spotlight the non-metallic oxide, especially metal chalcogenides (MX; X = S, Se) based nanostructured electrode materials for electrochemical SCs. Different non-metallic oxide materials are highlighted in various categories, such as transition metal sulfides and selenides materials. Finally, the designing strategy and future improvements on metal chalcogenide materials for the application of electrochemical SCs are also discussed. PMID:29671823

  3. Sensitive electrochemical sensing for polycyclic aromatic amines based on a novel core-shell multiwalled carbon nanotubes@ graphene oxide nanoribbons heterostructure.

    Science.gov (United States)

    Zhu, Gangbing; Yi, Yinhui; Han, Zhixiang; Wang, Kun; Wu, Xiangyang

    2014-10-03

    Being awfully harmful to the environment and human health, the qualitative and quantitative determinations of polycyclic aromatic amines (PAAs) are of great significance. In this paper, a novel core-shell heterostructure of multiwalled carbon nanotubes (MWCNTs) as the core and graphene oxide nanoribbons (GONRs) as the shell (MWCNTs@GONRs) was produced from longitudinal partially unzipping of MWCNTs side walls using a simple wet chemical strategy and applied for electrochemical determination of three kinds of PAAs (1-aminopyrene (1-AP), 1-aminonaphthalene and 3,3'-diaminobiphenyl). Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis and electrochemical methods were used to characterize the as-prepared MWCNTs@GONRs. Due to the synergistic effects from MWCNTs and GONRs, the oxidation currents of PAAs at the MWCNTs@GONRs modified glassy carbon (GC) electrode are much higher than that at the MWCNTs/GC, graphene/GC and bare GC electrodes. 1-AP was used as the representative analyte to demonstrate the sensing performance of the MWCNTs@GONRs/GC electrode, and the proposed modified electrode has a linear response range of 8.0-500.0 nM with a detection limit of 1.5 nM towards 1-AP. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Phosphomolybdic acid functionalized graphene loading copper nanoparticles modified electrodes for non-enzymatic electrochemical sensing of glucose

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jiaoyan; Cao, Xiyue [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Xia, Jianfei, E-mail: xiajianfei@126.com [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Gong, Shida [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Wang, Zonghua, E-mail: wangzonghua@qdu.edu.cn [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Lu, Lin [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Zibo Normal College, Zibo, Shandong 255100 (China)

    2016-08-31

    A sensitive non-enzymatic glucose electrochemical biosensor (Cu/PMo{sub 12}-GR/GCE) was developed based on the combination of copper nanoparticles (CuNPs) and phosphomolybdic acid functionalized graphene (PMo{sub 12}-GR). PMo{sub 12}-GR films were modified on the surface of glassy carbon electrode (GCE) through electrostatic self-assembly with the aid of poly diallyl dimethyl ammonium chloride (PDDA). Then CuNPs were successfully decorated onto the PMo{sub 12}-GR modified GCE through electrodeposition. The morphology of Cu/PMo{sub 12}-GR/GCE was characterized by scanning electron microscope (SEM). Cyclic voltammetry (CV) and chronoamperometry were used to investigate the electrochemical performances of the biosensor. The results indicated that the modified electrode displayed a synergistic effect of PMo{sub 12}-GR sheets and CuNPs towards the electro-oxidation of glucose in the alkaline solution. At the optimal detection potential of 0.50 V, the response towards glucose presented a linear response ranging from 0.10 μM to 1.0 mM with a detection limit of 3.0 × 10{sup −2} μM (S/N = 3). In addition, Cu/PMo{sub 12}-GR/GCE possessed a high selectivity, good reproducibility, excellent stability and acceptable recovery, which indicating the potential application in clinical field. - Highlights: • Cu/PMo{sub 12}-GR/GCE as a non-enzymatic glucose electrochemical sensor. • PMo{sub 12} is efficient for the uniform growth of Cu-NPs and electron transport. • The sensor exhibits good sensitivity and specificity towards glucose.

  5. Advances in the development of remote sensing technology for agricultural applications

    Science.gov (United States)

    Powers, J. E.; Erb, R. B.; Hall, F. G.; Macdonald, R. B.

    1979-01-01

    The application of remote sensing technology to crop forecasting is discussed. The importance of crop forecasts to the world economy and agricultural management is explained, and the development of aerial and spaceborne remote sensing for global crop forecasting by the United States is outlined. The structure, goals and technical aspects of the Large Area Crop Inventory Experiment (LACIE) are presented, and main findings on the accuracy, efficiency, applicability and areas for further study of the LACIE procedure are reviewed. The current status of NASA crop forecasting activities in the United States and worldwide is discussed, and the objectives and organization of the newly created Agriculture and Resources Inventory Surveys through Aerospace Remote Sensing (AgRISTARS) program are presented.

  6. Fabrication and applications of copper sulfide (CuS) nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Shamraiz, Umair, E-mail: umairshamraiz@gmail.com; Hussain, Raja Azadar, E-mail: hussainazadar@gamil.com; Badshah, Amin, E-mail: aminbadshah@yahoo.com

    2016-06-15

    This review article presents different fabrication procedures (under the headlines of solvothermal routes, aerosol methods, solution methods and thermolysis), and applications (photocatalytic degradation, ablation of cancer cells, electrode material in lithium ion batteries and in gas sensing, organic solar cells, field emission properties, super capacitor applications, photoelectrochemical performance of QDSCs, photocatalytic reduction of organic pollutants, electrochemical bio sensing, enhanced PEC characteristics of pre-annealed CuS film electrodes) of copper sulfide (Covellite). - Highlights: • This review article presents the synthesis and applications of copper sulfide. • CuS has been used over the years for different applications in nanoscience. • Different synthetic protocols are followed for their preparation which help in the possible modifications in the morphology of CuS.

  7. NanoBiosensing Principles, Development and Application

    CERN Document Server

    Ju, Huangxian; Wang, Joseph

    2011-01-01

    This book will cover the full scope of nanobiosensing, which combines the newest research results in the cross-disciplines of chemistry, biology, and materials science with biosensing and bioanalysis to develop novel detection principles, sensing mechanisms, and device engineering methods. It not only covers the important types of nanomaterials for biosensing applications, including carbon nanotubes, carbon nanofiber, quantum dots, fullerenes, fluorescent and biological molecules, etc., but also illustrates a wide range of sensing principles, including electrochemical detection, fluorescence, chemiluminesence, antibody-antigen interactions, and magnetic detection. The book details novel developments in the methodology and devices of biosensing and bioanalysis combined with nanoscience and nanotechnology, as well as their applications in biomedicine and environmental monitoring. Furthermore, the reported works on the application and biofunction of nanoparticles have attracted extensive attention and interest, ...

  8. Application of Nanomaterials in Production of Self-Sensing Concretes: Contemporary Developments and Prospects

    Directory of Open Access Journals (Sweden)

    Horszczaruk E.

    2016-09-01

    Full Text Available In the recent years structural health monitoring (SHM has gathered spectacular attention in civil engineering applications. Application of such composites enable to improve the safety and performance of structures. Recent advances in nanotechnology have led to development of new family of sensors - self-sensing materials. These materials enable to create the so-called “smart concrete” exhibiting self-sensing ability. Application of self-sensing materials in cement-based materials enables to detect their own state of strain or stress reflected as a change in their electrical properties. The variation of strain or stress is associated with the variation in material’s electrical characteristics, such as resistance or impedance. Therefore, it is possible to efficiently detect and localize crack formation and propagation in selected concrete element. This review is devoted to present contemporary developments in application of nanomaterials in self-sensing cement-based composites and future directions in the field of smart structures.

  9. Multimodal Sensing Strategy Using pH Dependent Fluorescence Switchable System

    Science.gov (United States)

    Muthurasu, A.; Ganesh, V.

    2016-12-01

    Biomolecules assisted preparation of fluorescent gold nanoparticles (FL-Au NPs) has been reported in this work using glucose oxidase enzyme as both reducing and stabilizing agent and demonstrated their application through multimodal sensing strategy for selective detection of cysteine (Cys). Three different methods namely fluorescence turn OFF-ON strategy, naked eye detection and electrochemical methods are used for Cys detection by employing FL-Au NPs as a common probe. In case of fluorescence turn-OFF method a strong interaction between Au NPs and thiol results in quenching of fluorescence due to replacement of glucose oxidase by Cys at neutral pH. Second mode is based on fluorescence switch-ON strategy where initial fluorescence is significantly quenched by either excess acid or base and further addition of Cys results in appearance of rosy-red and green fluorescence respectively. Visual colour change and fluorescence emission arises due to etching of Au atoms on the surface by thiol leading to formation of Au nanoclusters. Finally, electrochemical sensing of Cys is also carried out using cyclic voltammetry in 0.1 M PBS solution. These findings provide a suitable platform for Cys detection over a wide range of pH and concentration levels and hence the sensitivity can also be tuned accordingly.

  10. Electrochemical impedance spectroscopy based MEMS sensors for phthalates detection in water and juices

    KAUST Repository

    Zia, Asif I

    2013-06-10

    Phthalate esters are ubiquitous environmental and food pollutants well known as endocrine disrupting compounds (EDCs). These developmental and reproductive toxicants pose a grave risk to the human health due to their unlimited use in consumer plastic industry. Detection of phthalates is strictly laboratory based time consuming and expensive process and requires expertise of highly qualified and skilled professionals. We present a real time, non-invasive, label free rapid detection technique to quantify phthalates\\' presence in deionized water and fruit juices. Electrochemical impedance spectroscopy (EIS) technique applied to a novel planar inter-digital (ID) capacitive sensor plays a vital role to explore the presence of phthalate esters in bulk fluid media. The ID sensor with multiple sensing gold electrodes was fabricated on silicon substrate using micro-electromechanical system (MEMS) device fabrication technology. A thin film of parylene C polymer was coated as a passivation layer to enhance the capacitive sensing capabilities of the sensor and to reduce the magnitude of Faradic current flowing through the sensor. Various concentrations, 0.002ppm through to 2ppm of di (2-ethylhexyl) phthalate (DEHP) in deionized water, were exposed to the sensing system by dip testing method. Impedance spectra obtained was analysed to determine sample conductance which led to consequent evaluation of its dielectric properties. Electro-chemical impedance spectrum analyser algorithm was employed to model the experimentally obtained impedance spectra. Curve fitting technique was applied to deduce constant phase element (CPE) equivalent circuit based on Randle\\'s equivalent circuit model. The sensing system was tested to detect different concentrations of DEHP in orange juice as a real world application. The result analysis indicated that our rapid testing technique is able to detect the presence of DEHP in all test samples distinctively.

  11. Electrochemical impedance spectroscopy based MEMS sensors for phthalates detection in water and juices

    International Nuclear Information System (INIS)

    Zia, Asif I; Syaifudin, A R Mohd; Mukhopadhyay, S C; Yu, P L; Al-Bahadly, I H; Gooneratne, Chinthaka P; Kosel, Juergen; Liao, Tai-Shan

    2013-01-01

    Phthalate esters are ubiquitous environmental and food pollutants well known as endocrine disrupting compounds (EDCs). These developmental and reproductive toxicants pose a grave risk to the human health due to their unlimited use in consumer plastic industry. Detection of phthalates is strictly laboratory based time consuming and expensive process and requires expertise of highly qualified and skilled professionals. We present a real time, non-invasive, label free rapid detection technique to quantify phthalates' presence in deionized water and fruit juices. Electrochemical impedance spectroscopy (EIS) technique applied to a novel planar inter-digital (ID) capacitive sensor plays a vital role to explore the presence of phthalate esters in bulk fluid media. The ID sensor with multiple sensing gold electrodes was fabricated on silicon substrate using micro-electromechanical system (MEMS) device fabrication technology. A thin film of parylene C polymer was coated as a passivation layer to enhance the capacitive sensing capabilities of the sensor and to reduce the magnitude of Faradic current flowing through the sensor. Various concentrations, 0.002ppm through to 2ppm of di (2-ethylhexyl) phthalate (DEHP) in deionized water, were exposed to the sensing system by dip testing method. Impedance spectra obtained was analysed to determine sample conductance which led to consequent evaluation of its dielectric properties. Electro-chemical impedance spectrum analyser algorithm was employed to model the experimentally obtained impedance spectra. Curve fitting technique was applied to deduce constant phase element (CPE) equivalent circuit based on Randle's equivalent circuit model. The sensing system was tested to detect different concentrations of DEHP in orange juice as a real world application. The result analysis indicated that our rapid testing technique is able to detect the presence of DEHP in all test samples distinctively.

  12. Portable Lock-in Amplifier-Based Electrochemical Method to Measure an Array of 64 Sensors for Point-of-Care Applications.

    Science.gov (United States)

    Hrdý, Radim; Kynclová, Hana; Klepáčová, Ivana; Bartošík, Martin; Neužil, Pavel

    2017-09-05

    We present a portable lock-in amplifier-based electrochemical sensing system. The basic unit (cluster) consists of four electrochemical cells (EC), each containing one pseudoreference electrode (PRE) and one working electrode (WE). All four ECs are simultaneously interrogated, each at different frequencies, with square wave pulses superposed on a sawtooth signal for cyclic voltammetry (CV). Lock-in amplification provides independent read-out of four signals, with excellent noise suppression. We expanded a single cluster system into an array of 16 clusters by using electronic switches. The chip with an array of ECs was fabricated using planar technology with a gap between a WE and a PRE of ≈2 μm, which results in partial microelectrode-type behavior. The basic electrode characterization was performed with the model case using a ferricyanide-ferrocyanide redox couple (Fe 2+ /Fe 3+ ) reaction, performing CV and differential pulse voltammetry (DPV). We then used this system to perform cyclic lock-in voltammetry (CLV) to measure concurrently responses of the four ECs. We repeated this method with all 64 ECs on the chip. The standard deviation of a peak oxidation and reduction current in a single channel consisting of 13 ECs was ≈7.46% and ≈5.6%, respectively. The four-EC configuration in each measured spot allows determination of nonperforming ECs and, thus, to eliminate potential false results. This system is built in a portable palm-size format suitable for point-of-care applications. It can perform either individual or multiple measurements of active compounds, such as biomarkers.

  13. Recent Advances in Electrochemical Biosensors Based on Fullerene-C60 Nano-Structured Platforms.

    Science.gov (United States)

    Pilehvar, Sanaz; De Wael, Karolien

    2015-11-23

    Nanotechnology is becoming increasingly important in the field of (bio)sensors. The performance and sensitivity of biosensors is greatly improved with the integration of nanomaterials into their construction. Since its first discovery, fullerene-C60 has been the object of extensive research. Its unique and favorable characteristics of easy chemical modification, conductivity, and electrochemical properties has led to its tremendous use in (bio)sensor applications. This paper provides a concise review of advances in fullerene-C60 research and its use as a nanomaterial for the development of biosensors. We examine the research work reported in the literature on the synthesis, functionalization, approaches to nanostructuring electrodes with fullerene, and outline some of the exciting applications in the field of (bio)sensing.

  14. High voltage electrophoretic deposition for electrochemical energy storage and other applications

    Science.gov (United States)

    Santhanagopalan, Sunand

    High voltage electrophoretic deposition (HVEPD) has been developed as a novel technique to obtain vertically aligned forests of one-dimensional nanomaterials for efficient energy storage. The ability to control and manipulate nanomaterials is critical for their effective usage in a variety of applications. Oriented structures of one-dimensional nanomaterials provide a unique opportunity to take full advantage of their excellent mechanical and electrochemical properties. However, it is still a significant challenge to obtain such oriented structures with great process flexibility, ease of processing under mild conditions and the capability to scale up, especially in context of efficient device fabrication and system packaging. This work presents HVEPD as a simple, versatile and generic technique to obtain vertically aligned forests of different one-dimensional nanomaterials on flexible, transparent and scalable substrates. Improvements on material chemistry and reduction of contact resistance have enabled the fabrication of high power supercapacitor electrodes using the HVEPD method. The investigations have also paved the way for further enhancements of performance by employing hybrid material systems and AC/DC pulsed deposition. Multi-walled carbon nanotubes (MWCNTs) were used as the starting material to demonstrate the HVEPD technique. A comprehensive study of the key parameters was conducted to better understand the working mechanism of the HVEPD process. It has been confirmed that HVEPD was enabled by three key factors: high deposition voltage for alignment, low dispersion concentration to avoid aggregation and simultaneous formation of holding layer by electrodeposition for reinforcement of nanoforests. A set of suitable parameters were found to obtain vertically aligned forests of MWCNTs. Compared with their randomly oriented counterparts, the aligned MWCNT forests showed better electrochemical performance, lower electrical resistance and a capability to

  15. Electrochemical performance of 3D porous Ni-Co oxide with electrochemically exfoliated graphene for asymmetric supercapacitor applications

    International Nuclear Information System (INIS)

    Kim, Dae Kyom; Hwang, Minsik; Ko, Dongjin; Kang, Jeongmin; Seong, Kwang-dong; Piao, Yuanzhe

    2017-01-01

    Graphical abstract: The paper reported the Ni-Co oxide/electrochemically exfoliated graphene nanocomposites with 3D porous nano-architectures (NC-EEG) using a simple low temperature solution method combined with a thermal annealing treatment. 3D porous architectures provide large surface areas and shorten electron diffusion pathways for high performance asymmetric supercapacitors. Display Omitted -- Highlights: •A simple low temperature solution method was used for preparing NC-EEG. •Graphene sheets were obtained by electrochemically exfoliation process. •A high capacity of NC-EEG in a three-electrode system, as high as 649 C g −1 , was recorded. •Asymmetric supercapacitor based on NC-EEG exhibited excellent energy density and power density. -- Abstract: Ni-Co oxide, one of the binary metal oxides, has many advantages for use in high-performance supercapacitor electrode materials due to its relatively high electronic conductivity and improved electrochemical performance. In this work, Ni-Co oxide/electrochemically exfoliated graphene nanocomposites (NC-EEG) are successfully synthesized using a simple low temperature solution method combined with a thermal annealing treatment. Graphene sheets are directly obtained by an electrochemical exfoliation process with graphite foil, which is very simple, environmentally friendly, and has a relatively short reaction time. This electrochemically exfoliated graphene (EEG) can improve the electrical conductivity of the Ni-Co oxide nanostructures. The as-prepared NC-EEG nanocomposites have 3D porous architectures that can provide large surface areas and shorten electron diffusion pathways. Electrochemical properties were performed by cyclic voltammetry and galvanostatic charge/discharge in a 6 M KOH electrolyte. The NC-EEG nanocomposites exhibited a high capacity value of 649 C g −1 at a current density of 1.0 A g −1 . The asymmetric supercapacitors, manufactured on the basis of NC-EEG nanocomposites as a positive

  16. Nanostructured Electrode Materials for Electrochemical Capacitor Applications.

    Science.gov (United States)

    Choi, Hojin; Yoon, Hyeonseok

    2015-06-02

    The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication of electrochemical capacitor electrodes and also give a brief overview of electric double-layer capacitors, pseudocapacitors, and hybrid capacitors. From a materials point of view, the latest trends in electrochemical capacitor research are also discussed through extensive analysis of the literature and by highlighting notable research examples (published mostly since 2013). Finally, a perspective on next-generation capacitor technology is also given, including the challenges that lie ahead.

  17. Electrochemical polymer electrolyte membranes

    CERN Document Server

    Fang, Jianhua; Wilkinson, David P

    2015-01-01

    Electrochemical Polymer Electrolyte Membranes covers PEMs from fundamentals to applications, describing their structure, properties, characterization, synthesis, and use in electrochemical energy storage and solar energy conversion technologies. Featuring chapters authored by leading experts from academia and industry, this authoritative text: Discusses cutting-edge methodologies in PEM material selection and fabricationPoints out important challenges in developing PEMs and recommends mitigation strategies to improve PEM performanceAnalyzes the cur

  18. Aptamer/quantum dot-based simultaneous electrochemical detection of multiple small molecules

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Haixia [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Jiang Bingying [School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400040 (China); Xiang Yun, E-mail: yunatswu@swu.edu.cn [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Zhang Yuyong; Chai Yaqin [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Yuan Ruo, E-mail: yuanruo@swu.edu.cn [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)

    2011-03-04

    A novel strategy for 'signal on' and sensitive one-spot simultaneous detection of multiple small molecular analytes based on electrochemically encoded barcode quantum dot (QD) tags is described. The target analytes, adenosine triphosphate (ATP) and cocaine, respectively, are sandwiched between the corresponding set of surface-immobilized primary binding aptamers and the secondary binding aptamer/QD bioconjugates. The captured QDs yield distinct electrochemical signatures after acid dissolution, whose position and size reflect the identity and level, respectively, of the corresponding target analytes. Due to the inherent amplification feature of the QD labels and the 'signal on' detection scheme, as well as the sensitive monitoring of the metal ions released upon acid dissolution of the QD labels, low detection limits of 30 nM and 50 nM were obtained for ATP and cocaine, respectively, in our assays. Our multi-analyte sensing system also shows high specificity to target analytes and promising applicability to complex sample matrix, which makes the proposed assay protocol an attractive route for screening of small molecules in clinical diagnosis.

  19. Nanostructure of highly aromatic graphene nanosheets -- From optoelectronics to electrochemical energy storage applications

    Science.gov (United States)

    Biswas, Sanjib

    The exceptional electrical properties along with intriguing physical and chemical aspects of graphene nanosheets can only be realized by nanostructuring these materials through the homogeneous and orderly distribution of these nanosheets without compromising the aromaticity of the native basal plane. Graphene nanosheets prepared by direct exfoliation as opposed to the graphene oxide route are necessary in order to preserve the native chemical properties of graphene basal planes. This research has been directed at optimally combining the diverse physical and chemical aspects of graphene nanosheets such as particle size, surface area and edge chemistry to fabricate nanostructured architectures for optoelectronics and high power electrochemical energy storage applications. In the first nanostructuring effort, a monolayer of these ultrathin, highly hydrophobic graphene nanosheets was prepared on a large area substrate via self-assembly at the liquid-liquid interface. Driven by the minimization of interfacial energy these planar graphene nanosheets produce a close packed monolayer structure at the liquid-liquid interface. The resulting monolayer film exhibits high electrical conductivity of more than 1000 S/cm and an optical transmission of more than 70-80% between wavelengths of 550 nm and 2000 nm making it an ideal candidate for optoelectronic applications. In the second part of this research, nanostructuring was used to create a configuration suitable for supercapacitor applications. A free standing, 100% binder free multilayer, flexible film consisting of monolayers of graphene nanosheets was prepared by utilizing the van der Waals forces of attraction between the basal plans of the graphene nanosheets coupled with capillary driven and drying-induced collapse. A major benefit in this approach is that the graphene nanosheet's attractive physical and chemical characteristics can be synthesized into an architecture consisting of large and small nanosheets to create an

  20. Preparation of Nickel Cobalt Sulfide Hollow Nanocolloids with Enhanced Electrochemical Property for Supercapacitors Application

    Science.gov (United States)

    Chen, Zhenhua; Wan, Zhanghui; Yang, Tiezhu; Zhao, Mengen; Lv, Xinyan; Wang, Hao; Ren, Xiuli; Mei, Xifan

    2016-01-01

    Nanostructured functional materials with hollow interiors are considered to be good candidates for a variety of advanced applications. However, synthesis of uniform hollow nanocolloids with porous texture via wet chemistry method is still challenging. In this work, nickel cobalt precursors (NCP) in sub-micron sized spheres have been synthesized by a facile solvothermal method. The subsequent sulfurization process in hydrothermal system has changed the NCP to nickel cobalt sulfide (NCS) with porous texture. Importantly, the hollow interiors can be tuned through the sulfurization process by employing different dosage of sulfur source. The derived NCS products have been fabricated into supercapacitor electrodes and their electrochemical performances are measured and compared, where promising results were found for the next-generation high-performance electrochemical capacitors. PMID:27114165

  1. Bio-Techniques in Electrochemical Transducers: an Overview

    Directory of Open Access Journals (Sweden)

    VIKAS

    2007-08-01

    Full Text Available Novelty in fabrication & designing of biosensors are being carried out at a high rate as these devices become increasingly popular in fields like environmental monitoring, bioterrorism, food analyses and most importantly in the area of health care and diagnostics. This rapidly expanding field has an annual growth rate of 65%, with major impetus from the health-care industry (30% of the world’s total analytical market supported with other analytical areas of food & environmental monitoring including defense needs. This context aims to highlight trends in practice for electrochemical biosensor design and construction. The availability and application of a vast range of polymers and copolymers associated with new sensing techniques have led to remarkable innovation in the design and construction of biosensors, significant improvements in sensor function and the emergence of new types of biosensor. Nevertheless, in vivo applications remain limited by functional deterioration due to surface fouling by biological components. However, use of new material and novelty in fabrication, raising hopes that the problems related to decreased functional of the bioanalytical layer be solved in time.

  2. Remote sensing applications for transportation and traffic engineering studies: A review of the literature

    Science.gov (United States)

    Epps, J. W.

    1973-01-01

    Current references were surveyed for the application of remote sensing to traffic and transportation studies. The major problems are presented that concern traffic engineers and transportation managers, and the literature references that discuss remote sensing applications are summarized.

  3. Development of electrochemical impedance spectroscopy based sensing system for DEHP detection

    KAUST Repository

    Zia, Asif I.; Mohd. Syaifudin, A. R.; Mukhopadhyay, Subhas Chandra; Al-Bahadly, Ibrahim H.; Yu, Paklam; Gooneratne, Chinthaka Pasan; Kosel, Jü rgen

    2011-01-01

    This research work presents a real time and non invasive technique to detect Di(2-ethylhexyl) phthalate (DEHP)content in purified water and quantify its concentration by Electrochemical Impedance Spectroscopy(E.I.S.). Planar Inter-digital capacitive

  4. Hematite Nanoparticles-Modified Electrode Based Electrochemical Sensing Platform for Dopamine

    Directory of Open Access Journals (Sweden)

    Khosro Zangeneh Kamali

    2014-01-01

    Full Text Available Hematite (α-Fe2O3 nanoparticles were synthesized by the solid transformation of ferrous hydroxide and ferrihydrite in hydrothermal condition. The as-prepared α-Fe2O3 nanoparticles were characterized by UV-vis, PL, XRD, Raman, TEM, AFM, FESEM, and EDX analysis. The experimental results indicated the formation of uniform hematite nanoparticles with an average size of 45 nm and perfect crystallinity. The electrochemical behavior of a GC/α-Fe2O3 electrode was studied using CV and EIS techniques with an electrochemical probe, [Fe(CN6]3−/4− redox couple. The electrocatalytic activity was investigated toward DA oxidation in a phosphate buffer solution (pH 6.8 by varying different experimental parameters. The chronoamperometric study showed a linear response in the range of 0–2 μM with LoD of 1.6 μM for DA. Square wave voltammetry showed a linear response in the range of 0–35 μM with LoD of 236 nM for DA.

  5. Hematite Nanoparticles-Modified Electrode Based Electrochemical Sensing Platform for Dopamine

    Science.gov (United States)

    Zangeneh Kamali, Khosro; Alagarsamy, Pandikumar; Huang, Nay Ming; Ong, Boon Hoong; Lim, Hong Ngee

    2014-01-01

    Hematite (α-Fe2O3) nanoparticles were synthesized by the solid transformation of ferrous hydroxide and ferrihydrite in hydrothermal condition. The as-prepared α-Fe2O3 nanoparticles were characterized by UV-vis, PL, XRD, Raman, TEM, AFM, FESEM, and EDX analysis. The experimental results indicated the formation of uniform hematite nanoparticles with an average size of 45 nm and perfect crystallinity. The electrochemical behavior of a GC/α-Fe2O3 electrode was studied using CV and EIS techniques with an electrochemical probe, [Fe(CN)6]3−/4− redox couple. The electrocatalytic activity was investigated toward DA oxidation in a phosphate buffer solution (pH 6.8) by varying different experimental parameters. The chronoamperometric study showed a linear response in the range of 0–2 μM with LoD of 1.6 μM for DA. Square wave voltammetry showed a linear response in the range of 0–35 μM with LoD of 236 nM for DA. PMID:25136664

  6. Electrochemical detection on electrowetting-on-dielectric digital microfluidic chip.

    Science.gov (United States)

    Karuwan, Chanpen; Sukthang, Kreeta; Wisitsoraat, Anurat; Phokharatkul, Ditsayut; Patthanasettakul, Viyapol; Wechsatol, Wishsanuruk; Tuantranont, Adisorn

    2011-06-15

    In this work, the use of three-electrode electrochemical sensing system with an electrowetting-on-dielectric (EWOD) digital microfluidic device is reported for quantitative analysis of iodide. T-junction EWOD mixer device was designed using arrays of 50-μm spaced square electrodes for mixing buffer reagent and analyte droplets. For fabrication of EWOD chips, 5-μm thick silver EWOD electrodes were formed on a glass substrate by means of sputtering and lift-off process. PDMS and Teflon thin films were then coated on the electrodes by spin coating to yield hydrophobic surface. An external three-electrode system consisting of Au working, Ag reference and Pt auxiliary wires were installed over EWOD electrodes at the end of T-junction mixer. In experiment, a few-microliter droplets of Tris buffer and iodide solutions were moved toward the mixing junction and transported toward electrochemical electrodes by EWOD process. A short processing time within seconds was achieved at EWOD applied voltage of 300V. The analyte droplets mixed with different concentrations were successfully analyzed by cyclic voltametry. Therefore, the combination of EWOD digital microfluidic and electrochemical sensing system has successfully been demonstrated for rapid chemical analysis with minimal reagent consumption. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Paper as a platform for sensing applications and other devices: a review.

    Science.gov (United States)

    Mahadeva, Suresha K; Walus, Konrad; Stoeber, Boris

    2015-04-29

    Paper is a ubiquitous material that has various applications in day to day life. A sheet of paper is produced by pressing moist wood cellulose fibers together. Paper offers unique properties: paper allows passive liquid transport, it is compatible with many chemical and biochemical moieties, it exhibits piezoelectricity, and it is biodegradable. Hence, paper is an attractive low-cost functional material for sensing devices. In recent years, researchers in the field of science and engineering have witnessed an exponential growth in the number of research contributions that focus on the development of cost-effective and scalable fabrication methods and new applications of paper-based devices. In this review article, we highlight recent advances in the development of paper-based sensing devices in the areas of electronics, energy storage, strain sensing, microfluidic devices, and biosensing, including piezoelectric paper. Additionally, this review includes current limitations of paper-based sensing devices and points out issues that have limited the commercialization of some of the paper-based sensing devices.

  8. Digital holography and wavefront sensing principles, techniques and applications

    CERN Document Server

    Schnars, Ulf; Watson, John; Jüptner, Werner

    2015-01-01

    This book presents a self-contained treatment of the principles and major applications of digital hologram recording and numerical reconstruction (Digital Holography). This second edition has been significantly revised and enlarged. The authors have extended the chapter on Digital Holographic Microscopy to incorporate new sections on particle sizing, particle image velocimetry and underwater holography. A new chapter now deals comprehensively and extensively with computational wave field sensing. These techniques represent a fascinating alternative to standard interferometry and Digital Holography. They enable wave field sensing without the requirement of a particular reference wave, thus allowing the use of low brilliance light sources and even liquid-crystal displays (LCD) for interferometric applications.              

  9. Diamond surface functionalization with biomimicry - Amine surface tether and thiol moiety for electrochemical sensors

    Science.gov (United States)

    Sund, James B.; Causey, Corey P.; Wolter, Scott D.; Parker, Charles B.; Stoner, Brian R.; Toone, Eric J.; Glass, Jeffrey T.

    2014-05-01

    The surface of conducting diamond was functionalized with a terminal thiol group that is capable of binding and detecting nitrogen-oxygen species. The functionalization process employed multiple steps starting with doped diamond films grown by plasma enhanced chemical vapor deposition followed by hydrogen termination and photochemical attachment of a chemically protected amine alkene. The surface tether was deprotected to reveal the amine functionality, which enabled the tether to be extended with surface chemistry to add a terminal thiol moiety for electrochemical sensing applications. Each step of the process was validated using X-ray photoelectron spectroscopy analysis.

  10. Apodization Optimization of FBG Strain Sensor for Quasi-Distributed Sensing Measurement Applications

    Directory of Open Access Journals (Sweden)

    Fahd Chaoui

    2016-01-01

    Full Text Available A novel optimized apodization of Fiber Bragg Grating Sensor (FBGS for quasi-distributed strain sensing applications is developed and introduced in this paper. The main objective of the proposed optimization is to obtain a reflectivity level higher than 90% and a side lobe level around −40 dB, which is suitable for use in quasi-distributed strain sensing application. For this purpose, different design parameters as apodization profile, grating length, and refractive index have been investigated to enhance and optimize the FBGS design. The performance of the proposed apodization has then been compared in terms of reflectivity, side lobe level (SLL, and full width at half maximum (FWHM with apodization profiles proposed by other authors. The optimized sensor is integrated on quasi-distributed sensing system of 8 sensors demonstrating high reliability. Wide strain sensitivity range for each channel has also been achieved in the quasi-distributed system. Results prove the efficiency of the proposed optimization which can be further implemented for any quasi-distributed sensing application.

  11. Nanostructured Electrode Materials for Electrochemical Capacitor Applications

    Directory of Open Access Journals (Sweden)

    Hojin Choi

    2015-06-01

    Full Text Available The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication of electrochemical capacitor electrodes and also give a brief overview of electric double-layer capacitors, pseudocapacitors, and hybrid capacitors. From a materials point of view, the latest trends in electrochemical capacitor research are also discussed through extensive analysis of the literature and by highlighting notable research examples (published mostly since 2013. Finally, a perspective on next-generation capacitor technology is also given, including the challenges that lie ahead.

  12. Materials for electrochemical capacitors

    Science.gov (United States)

    Simon, Patrice; Gogotsi, Yury

    2008-11-01

    Electrochemical capacitors, also called supercapacitors, store energy using either ion adsorption (electrochemical double layer capacitors) or fast surface redox reactions (pseudo-capacitors). They can complement or replace batteries in electrical energy storage and harvesting applications, when high power delivery or uptake is needed. A notable improvement in performance has been achieved through recent advances in understanding charge storage mechanisms and the development of advanced nanostructured materials. The discovery that ion desolvation occurs in pores smaller than the solvated ions has led to higher capacitance for electrochemical double layer capacitors using carbon electrodes with subnanometre pores, and opened the door to designing high-energy density devices using a variety of electrolytes. Combination of pseudo-capacitive nanomaterials, including oxides, nitrides and polymers, with the latest generation of nanostructured lithium electrodes has brought the energy density of electrochemical capacitors closer to that of batteries. The use of carbon nanotubes has further advanced micro-electrochemical capacitors, enabling flexible and adaptable devices to be made. Mathematical modelling and simulation will be the key to success in designing tomorrow's high-energy and high-power devices.

  13. Light-Regulated Electrochemical Sensor Array for Efficiently Discriminating Hazardous Gases.

    Science.gov (United States)

    Liang, Hongqiu; Zhang, Xin; Sun, Huihui; Jin, Han; Zhang, Xiaowei; Jin, Qinghui; Zou, Jie; Haick, Hossam; Jian, Jiawen

    2017-10-27

    Inadequate detection limit and unsatisfactory discrimination features remain the challenging issues for the widely applied electrochemical gas sensors. Quite recently, we confirmed that light-regulated electrochemical reaction significantly enhanced the electrocatalytic activity, and thereby can potentially extend the detection limit to the parts per billion (ppb) level. Nevertheless, impact of the light-regulated electrochemical reaction on response selectivity has been discussed less. Herein, we systematically report on the effect of illumination on discrimination features via design and fabrication of a light-regulated electrochemical sensor array. Upon illumination (light on), response signal to the examined gases (C 3 H 6 , NO, and CO) is selectively enhanced, resulting in the sensor array demonstrating disparate response patterns when compared with that of the sensor array operated at light off. Through processing all the response patterns derived from both light on and light off with a pattern recognition algorithm, a satisfactory discrimination feature is observed. In contrast, apparent mutual interference between NO and CO is found when the sensor array is solely operated without illumination. The impact mechanism of the illumination is studied and it is deduced that the effect of the illumination on the discriminating features can be mainly attributed to the competition of electrocatalytic activity and gas-phase reactivity. If the enhanced electrocatalytic activity (to specific gas) dominates the whole sensing progress, enhancements in the corresponding response signal would be observed upon illumination. Otherwise, illumination gives a negligible impact. Hence, the response signal to part of the examined gases is selectively enhanced by illumination. Conclusively, light-regulated electrochemical reaction would provide an efficient approach to designing future smart sensing devices.

  14. Deep reduced PEDOT films support electrochemical applications: Biomimetic color front.

    Directory of Open Access Journals (Sweden)

    Toribio Fernandez OTERO

    2015-02-01

    Full Text Available Most of the literature accepts, despite many controversial results, that during oxidation/reduction films of conducting polymers move from electronic conductors to insulators. Thus, engineers and device’s designers are forced to use metallic supports to reoxidize the material for reversible device work. Electrochromic front experiments appear as main visual support of the claimed insulating nature of reduced conducting polymers. Here we present a different design of the biomimetic electrochromic front that corroborates the electronic and ionic conducting nature of deep reduced films. The direct contact PEDOT metal/electrolyte and film/electrolyte was prevented from electrolyte contact until 1cm far from the metal contact with protecting Parafilm®. The deep reduced PEDOT film supports the flow of high currents promoting reaction induced electrochromic color changes beginning 1 cm far from the metal-polymer electrical contact and advancing, through the reduced film, towards the metal contact. Reverse color changes during oxidation/reduction always are initiated at the film/electrolyte contact advancing, under the protecting film, towards the film/metal contact. Both reduced and oxidized states of the film demonstrate electronic and ionic conductivities high enough to be used for electronic applications or, as self-supported electrodes, for electrochemical devices. The electrochemically stimulated conformational relaxation (ESCR model explains those results.

  15. Impact of carbon-fluorine doped titanium dioxide in the performance of an electrochemical sensing of dopamine and rosebengal sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Abinaya C

    2015-01-01

    Full Text Available The role of Fluorine and Carbon as dopants in the TiO2 based electrochemical sensor and DSSC were presented in this work. A series of Carbon nano-cones and disc doped TiO2 (TC, Fluorine doped TiO2 (FT and C & F co-doped TiO2 (CFT powdered samples were prepared via solid state synthesis. The CFT film showed excellent electrochemical sensitivity to the oxidation of dopamine in aqueous solution and could be employed as a dopamine sensor. The proposed sensor exhibited good linear response in the range of 10-820 μM with a detection limit of 3.6 μM under optimum conditions. The photovoltaic performances of Rose Bengal sensitized solar cells were assessed through I-V measurements. The CFT based DSSC shows a short-circuit current density and a power conversion efficiency (η of 0.908 mA/cm2 and 0.163% respectively, which is 35% and 38% greater than the performance of other PT based cells. The characterization studies such as UV-Visible spectroscopy, Photoluminescence, TEM and EPR spectroscopy were utilized for further investigation, which helps us to understand how fluorine and carbon play a part in dopamine sensing and solar energy conversion.

  16. Earth Remote Sensing for Weather Forecasting and Disaster Applications

    Science.gov (United States)

    Molthan, Andrew; Bell, Jordan; Case, Jonathan; Cole, Tony; Elmer, Nicholas; McGrath, Kevin; Schultz, Lori; Zavodsky, Brad

    2016-01-01

    NASA's constellation of current missions provide several opportunities to apply satellite remote sensing observations to weather forecasting and disaster response applications. Examples include: Using NASA's Terra and Aqua MODIS, and the NASA/NOAA Suomi-NPP VIIRS missions to prepare weather forecasters for capabilities of GOES-R; Incorporating other NASA remote sensing assets for improving aspects of numerical weather prediction; Using NASA, NOAA, and international partner resources (e.g. ESA/Sentinel Series); and commercial platforms (high-res, or UAV) to support disaster mapping.

  17. International Conference on Remote Sensing Applications for Archaeological Research and World Heritage Conservation

    Science.gov (United States)

    2002-01-01

    Contents include the following: Monitoring the Ancient Countryside: Remote Sensing and GIS at the Chora of Chersonesos (Crimea, Ukraine). Integration of Remote Sensing and GIS for Management Decision Support in the Pendjari Biosphere Reserve (Republic of Benin). Monitoring of deforestation invasion in natural reserves of northern Madagascar based on space imagery. Cartography of Kahuzi-Biega National Park. Cartography and Land Use Change of World Heritage Areas and the Benefits of Remote Sensing and GIS for Conservation. Assessing and Monitoring Vegetation in Nabq Protected Area, South Sinai, Egypt, using combine approach of Satellite Imagery and Land Surveys. Evaluation of forage resources in semi-arid savannah environments with satellite imagery: contribution to the management of a protected area (Nakuru National Park) in Kenya. SOGHA, the Surveillance of Gorilla Habitat in World Heritage sites using Space Technologies. Application of Remote Sensing to monitor the Mont-Saint-Michel Bay (France). Application of Remote Sensing & GIS for the Conservation of Natural and Cultural Heritage Sites of the Southern Province of Sri Lanka. Social and Environmental monitoring of a UNESCO Biosphere Reserve: Case Study over the Vosges du Nord and Pfalzerwald Parks using Corona and Spot Imagery. Satellite Remote Sensing as tool to Monitor Indian Reservation in the Brazilian Amazonia. Remote Sensing and GIS Technology for Monitoring UNESCO World Heritage Sites - A Pilot Project. Urban Green Spaces: Modern Heritage. Monitoring of the technical condition of the St. Sophia Cathedral and related monastic buildings in Kiev with Space Applications, geo-positioning systems and GIS tools. The Murghab delta palaeochannel Reconstruction on the Basis of Remote Sensing from Space. Acquisition, Registration and Application of IKONOS Space Imagery for the cultural World Heritage site at Mew, Turkmenistan. Remote Sensing and VR applications for the reconstruction of archaeological landscapes

  18. Biomolecule-embedded metal-organic frameworks as an innovative sensing platform.

    Science.gov (United States)

    Kempahanumakkagari, Sureshkumar; Kumar, Vanish; Samaddar, Pallabi; Kumar, Pawan; Ramakrishnappa, Thippeswamy; Kim, Ki-Hyun

    Technological advancements combined with materials research have led to the generation of enormous types of novel substrates and materials for use in various biological/medical, energy, and environmental applications. Lately, the embedding of biomolecules in novel and/or advanced materials (e.g., metal-organic frameworks (MOFs), nanoparticles, hydrogels, graphene, and their hybrid composites) has become a vital research area in the construction of an innovative platform for various applications including sensors (or biosensors), biofuel cells, and bioelectronic devices. Due to the intriguing properties of MOFs (e.g., framework architecture, topology, and optical properties), they have contributed considerably to recent progresses in enzymatic catalysis, antibody-antigen interactions, or many other related approaches. Here, we aim to describe the different strategies for the design and synthesis of diverse biomolecule-embedded MOFs for various sensing (e.g., optical, electrochemical, biological, and miscellaneous) techniques. Additionally, the benefits and future prospective of MOFs-based biomolecular immobilization as an innovative sensing platform are discussed along with the evaluation on their performance to seek for further development in this emerging research area. Copyright © 2018. Published by Elsevier Inc.

  19. A mobile-agent-based wireless sensing network for structural monitoring applications

    International Nuclear Information System (INIS)

    Taylor, Stuart G; Farinholt, Kevin M; Figueiredo, Eloi; Moro, Erik A; Park, Gyuhae; Farrar, Charles R; Flynn, Eric B; Mascarenas, David L; Todd, Michael D

    2009-01-01

    A new wireless sensing network paradigm is presented for structural monitoring applications. In this approach, both power and data interrogation commands are conveyed via a mobile agent that is sent to sensor nodes to perform intended interrogations, which can alleviate several limitations of the traditional sensing networks. Furthermore, the mobile agent provides computational power to make near real-time assessments on the structural conditions. This paper will discuss such prototype systems, which are used to interrogate impedance-based sensors for structural health monitoring applications. Our wireless sensor node is specifically designed to accept various energy sources, including wireless energy transmission, and to be wirelessly triggered on an as-needed basis by the mobile agent or other sensor nodes. The capabilities of this proposed sensing network paradigm are demonstrated in the laboratory and the field

  20. Electrochemical and Infrared Absorption Spectroscopy Detection of SF₆ Decomposition Products.

    Science.gov (United States)

    Dong, Ming; Zhang, Chongxing; Ren, Ming; Albarracín, Ricardo; Ye, Rixin

    2017-11-15

    Sulfur hexafluoride (SF₆) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF₆ decomposition and ultimately generates several types of decomposition products. These SF₆ decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF₆ decomposition products, and electrochemical sensing (ES) and infrared (IR) spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF₆ gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF₆ decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF₆ gas decomposition and is verified to reliably and accurately detect the gas components and concentrations.

  1. Enhanced electrocatalytic activity of graphene-gold nanoparticles hybrids for peroxynitrite electrochemical detection on hemin-based electrode.

    Science.gov (United States)

    Wang, Beibei; Ji, Xueping; Ren, Jujie; Ni, Ruixing; Wang, Lin

    2017-12-01

    A simple, ultrasensitive peroxynitrite anion (ONOO - ) electrochemical sensing platform was developed by immobilizing hemin on a density controllable electrochemically reduced graphene oxide-Au nanoparticles (ERGO-AuNPs) nanohybrids. The ERGO-AuNPs in situ nanohybrids were produced onto a glass carbon electrode (GCE) by one-step electrodeposition, the density of which could be easily controlled by electrodeposited time. The morphology of ERGO-AuNPs nanohybrids was characterized by a scanning electron microscope (SEM). The ERGO-AuNPs nanohybrids showed a high electrocatalytic activity for immobilized-hemin, because the nanostructures hybrids could effectively promote electron transfer rate between hemin and the electrode. Due to nanohybrids-enhanced catalytic effect for hemin, they were firstly selected for use as a highly sensitive electrochemical platform for ONOO - detection. The resulted sensor showed a high electrocatalytic activity toward ONOO - oxidation, being free from the electroactive interferents, including nitrite, nitrate, dopamine and uric acid at an applied potential of 0.7V. The sensor exhibited a high sensitivity of 123.1nAμM -1 and a lower detection limit of 0.1μM, and a wide linear range of 2.4×10 -6 to 5.5×10 -5 M, which could be attributed to the synergy between ERGO and AuNPs in hybrids. The nanohybrids in situ preparation and ONOO - detection methods would be beneficial to developing other sensing interface and have promising applications in biological molecules analysis and clinical diagnostic. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Research Update: Nanoscale electrochemical transistors in correlated oxides

    Directory of Open Access Journals (Sweden)

    Teruo Kanki

    2017-04-01

    Full Text Available Large reversible changes of the electronic transport properties of solid-state oxide materials induced by electrochemical fields have received much attention as a new research avenue in iontronics. In this research update, dramatic transport changes in vanadium dioxide (VO2 nanowires were demonstrated by electric field-induced hydrogenation at room temperature through the nanogaps separated by humid air in a field-effect transistor structure with planar-type gates. This unique structure allowed us to investigate hydrogen intercalation and diffusion behavior in VO2 channels with respect to both time and space. Our results will contribute to further strategic researches to examine fundamental chemical and physical properties of devices and develop iontronic applications, as well as offering new directions to explore emerging functions for sensing, energy, and neuromorphologic devices combining ionic and electronic behaviors in solid-state materials.

  3. Validation plays the role of a "bridge" in connecting remote sensing research and applications

    Science.gov (United States)

    Wang, Zhiqiang; Deng, Ying; Fan, Yida

    2018-07-01

    Remote sensing products contribute to improving earth observations over space and time. Uncertainties exist in products of different levels; thus, validation of these products before and during their applications is critical. This study discusses the meaning of validation in depth and proposes a new definition of reliability for use with such products. In this context, validation should include three aspects: a description of the relevant uncertainties, quantitative measurement results and a qualitative judgment that considers the needs of users. A literature overview is then presented evidencing improvements in the concepts associated with validation. It shows that the root mean squared error (RMSE) is widely used to express accuracy; increasing numbers of remote sensing products have been validated; research institutes contribute most validation efforts; and sufficient validation studies encourage the application of remote sensing products. Validation plays a connecting role in the distribution and application of remote sensing products. Validation connects simple remote sensing subjects with other disciplines, and it connects primary research with practical applications. Based on the above findings, it is suggested that validation efforts that include wider cooperation among research institutes and full consideration of the needs of users should be promoted.

  4. Low-dimensional carbon and MXene-based electrochemical capacitor electrodes.

    Science.gov (United States)

    Yoon, Yeoheung; Lee, Keunsik; Lee, Hyoyoung

    2016-04-29

    Due to their unique structure and outstanding intrinsic physical properties such as extraordinarily high electrical conductivity, large surface area, and various chemical functionalities, low-dimension-based materials exhibit great potential for application in electrochemical capacitors (ECs). The electrical properties of electrochemical capacitors are determined by the electrode materials. Because energy charge storage is a surface process, the surface properties of the electrode materials greatly influence the electrochemical performance of the cell. Recently, graphene, a single layer of sp(2)-bonded carbon atoms arrayed into two-dimensional carbon nanomaterial, has attracted wide interest as an electrode material for electrochemical capacitor applications due to its unique properties, including a high electrical conductivity and large surface area. Several low-dimensional materials with large surface areas and high conductivity such as onion-like carbons (OLCs), carbide-derived carbons (CDCs), carbon nanotubes (CNTs), graphene, metal hydroxide, transition metal dichalcogenides (TMDs), and most recently MXene, have been developed for electrochemical capacitors. Therefore, it is useful to understand the current issues of low-dimensional materials and their device applications.

  5. Low-dimensional carbon and MXene-based electrochemical capacitor electrodes

    International Nuclear Information System (INIS)

    Yoon, Yeoheung; Lee, Hyoyoung; Lee, Keunsik

    2016-01-01

    Due to their unique structure and outstanding intrinsic physical properties such as extraordinarily high electrical conductivity, large surface area, and various chemical functionalities, low-dimension-based materials exhibit great potential for application in electrochemical capacitors (ECs). The electrical properties of electrochemical capacitors are determined by the electrode materials. Because energy charge storage is a surface process, the surface properties of the electrode materials greatly influence the electrochemical performance of the cell. Recently, graphene, a single layer of sp 2 -bonded carbon atoms arrayed into two-dimensional carbon nanomaterial, has attracted wide interest as an electrode material for electrochemical capacitor applications due to its unique properties, including a high electrical conductivity and large surface area. Several low-dimensional materials with large surface areas and high conductivity such as onion-like carbons (OLCs), carbide-derived carbons (CDCs), carbon nanotubes (CNTs), graphene, metal hydroxide, transition metal dichalcogenides (TMDs), and most recently MXene, have been developed for electrochemical capacitors. Therefore, it is useful to understand the current issues of low-dimensional materials and their device applications. (topical review)

  6. Satellite Remote Sensing for Coastal Management: A Review of Successful Applications.

    Science.gov (United States)

    McCarthy, Matthew J; Colna, Kaitlyn E; El-Mezayen, Mahmoud M; Laureano-Rosario, Abdiel E; Méndez-Lázaro, Pablo; Otis, Daniel B; Toro-Farmer, Gerardo; Vega-Rodriguez, Maria; Muller-Karger, Frank E

    2017-08-01

    Management of coastal and marine natural resources presents a number of challenges as a growing global population and a changing climate require us to find better strategies to conserve the resources on which our health, economy, and overall well-being depend. To evaluate the status and trends in changing coastal resources over larger areas, managers in government agencies and private stakeholders around the world have increasingly turned to remote sensing technologies. A surge in collaborative and innovative efforts between resource managers, academic researchers, and industry partners is becoming increasingly vital to keep pace with evolving changes of our natural resources. Synoptic capabilities of remote sensing techniques allow assessments that are impossible to do with traditional methods. Sixty years of remote sensing research have paved the way for resource management applications, but uncertainties regarding the use of this technology have hampered its use in management fields. Here we review examples of remote sensing applications in the sectors of coral reefs, wetlands, water quality, public health, and fisheries and aquaculture that have successfully contributed to management and decision-making goals.

  7. Satellite Remote Sensing for Coastal Management: A Review of Successful Applications

    Science.gov (United States)

    McCarthy, Matthew J.; Colna, Kaitlyn E.; El-Mezayen, Mahmoud M.; Laureano-Rosario, Abdiel E.; Méndez-Lázaro, Pablo; Otis, Daniel B.; Toro-Farmer, Gerardo; Vega-Rodriguez, Maria; Muller-Karger, Frank E.

    2017-08-01

    Management of coastal and marine natural resources presents a number of challenges as a growing global population and a changing climate require us to find better strategies to conserve the resources on which our health, economy, and overall well-being depend. To evaluate the status and trends in changing coastal resources over larger areas, managers in government agencies and private stakeholders around the world have increasingly turned to remote sensing technologies. A surge in collaborative and innovative efforts between resource managers, academic researchers, and industry partners is becoming increasingly vital to keep pace with evolving changes of our natural resources. Synoptic capabilities of remote sensing techniques allow assessments that are impossible to do with traditional methods. Sixty years of remote sensing research have paved the way for resource management applications, but uncertainties regarding the use of this technology have hampered its use in management fields. Here we review examples of remote sensing applications in the sectors of coral reefs, wetlands, water quality, public health, and fisheries and aquaculture that have successfully contributed to management and decision-making goals.

  8. Carbon paste electrode with covalently immobilized thionine for electrochemical sensing of hydrogen peroxide

    Science.gov (United States)

    Thenmozhi, K.; Sriman Narayanan, S.

    2017-11-01

    A water-soluble redox mediator, thionin was covalently immobilized to the functionalized graphite powder and a carbon paste electrode was fabricated from this modified graphite powder. The immobilization procedure proved to be effective in anchoring the thionin mediator in the graphite electrode setup without any leakage problem during the electrochemical studies. The covalent immobilization of the thionin mediator was studied with FT-IR and the electrochemical response of the thionin carbon paste electrode was optimized on varying the supporting electrolyte, pH and scan rate. The modified electrode exhibited well-defined electrocatalytic activity towards the reduction of H2O2 at a lower potential of -0.266 V with good sensitivity. The developed amperometric sensor was efficient towards H2O2 in the linear range from 2.46 × 10-5 M to 4.76 × 10-3 M, with a detection limit of 1.47 × 10-5 M respectively. Important advantages of this sensor are its excellent electrochemical performance, simple fabrication, easy renewability, reproducible analytical results, acceptable accuracy and good operational and long-term stability.

  9. Surface Acoustic Wave (SAW for Chemical Sensing Applications of Recognition Layers

    Directory of Open Access Journals (Sweden)

    Adnan Mujahid

    2017-11-01

    Full Text Available Surface acoustic wave (SAW resonators represent some of the most prominent acoustic devices for chemical sensing applications. As their frequency ranges from several hundred MHz to GHz, therefore they can record remarkably diminutive frequency shifts resulting from exceptionally small mass loadings. Their miniaturized design, high thermal stability and possibility of wireless integration make these devices highly competitive. Owing to these special characteristics, they are widely accepted as smart transducers that can be combined with a variety of recognition layers based on host-guest interactions, metal oxide coatings, carbon nanotubes, graphene sheets, functional polymers and biological receptors. As a result of this, there is a broad spectrum of SAW sensors, i.e., having sensing applications ranging from small gas molecules to large bio-analytes or even whole cell structures. This review shall cover from the fundamentals to modern design developments in SAW devices with respect to interfacial receptor coatings for exemplary sensor applications. The related problems and their possible solutions shall also be covered, with a focus on emerging trends and future opportunities for making SAW as established sensing technology.

  10. Surface Acoustic Wave (SAW) for Chemical Sensing Applications of Recognition Layers.

    Science.gov (United States)

    Mujahid, Adnan; Dickert, Franz L

    2017-11-24

    Surface acoustic wave (SAW) resonators represent some of the most prominent acoustic devices for chemical sensing applications. As their frequency ranges from several hundred MHz to GHz, therefore they can record remarkably diminutive frequency shifts resulting from exceptionally small mass loadings. Their miniaturized design, high thermal stability and possibility of wireless integration make these devices highly competitive. Owing to these special characteristics, they are widely accepted as smart transducers that can be combined with a variety of recognition layers based on host-guest interactions, metal oxide coatings, carbon nanotubes, graphene sheets, functional polymers and biological receptors. As a result of this, there is a broad spectrum of SAW sensors, i.e., having sensing applications ranging from small gas molecules to large bio-analytes or even whole cell structures. This review shall cover from the fundamentals to modern design developments in SAW devices with respect to interfacial receptor coatings for exemplary sensor applications. The related problems and their possible solutions shall also be covered, with a focus on emerging trends and future opportunities for making SAW as established sensing technology.

  11. Electrochemical studies of Copper, Tantalum and Tantalum Nitride surfaces in aqueous solutions for applications in chemical-mechanical and electrochemical-mechanical planarization

    Science.gov (United States)

    Sulyma, Christopher Michael

    This report will investigate fundamental properties of materials involved in integrated circuit (IC) manufacturing. Individual materials (one at a time) are studied in different electrochemical environmental solutions to better understand the kinetics associated with the polishing process. Each system tries to simulate a real CMP environment in order to compare our findings with what is currently used in industry. To accomplish this, a variety of techniques are used. The voltage pulse modulation technique is useful for electrochemical processing of metal and alloy surfaces by utilizing faradaic reactions like electrodeposition and electrodissolution. A theoretical framework is presented in chapter 4 to facilitate quantitative analysis of experimental data (current transients) obtained in this approach. A typical application of this analysis is demonstrated for an experimental system involving electrochemical removal of copper surface layers, a relatively new process for abrasive-free electrochemical mechanical planarization of copper lines used in the fabrication of integrated circuits. Voltage pulse modulated electrodissolution of Cu in the absence of mechanical polishing is activated in an acidic solution of oxalic acid and hydrogen peroxide. The current generated by each applied voltage step shows a sharp spike, followed by a double-exponential decay, and eventually attains the rectangular shape of the potential pulses. For the second system in chapter 5, open-circuit potential measurements, cyclic voltammetry and Fourier transform impedance spectroscopy have been used to study pH dependent surface reactions of Cu and Ta rotating disc electrodes (RDEs) in aqueous solutions of succinic acid (SA, a complexing agent), hydrogen peroxide (an oxidizer), and ammonium dodecyl sulfate (ADS, a corrosion inhibitor for Cu). The surface chemistries of these systems are relevant for the development of a single-slurry approach to chemical mechanical planarization (CMP) of Cu

  12. Construction of a zinc porphyrin-fullerene-derivative based nonenzymatic electrochemical sensor for sensitive sensing of hydrogen peroxide and nitrite.

    Science.gov (United States)

    Wu, Hai; Fan, Suhua; Jin, Xiaoyan; Zhang, Hong; Chen, Hong; Dai, Zong; Zou, Xiaoyong

    2014-07-01

    Enzymatic sensors possess high selectivity but suffer from some limitations such as instability, complicated modified procedure, and critical environmental factors, which stimulate the development of more sensitive and stable nonenzymatic electrochemical sensors. Herein, a novel nonenzymatic electrochemical sensor is proposed based on a new zinc porphyrin-fullerene (C60) derivative (ZnP-C60), which was designed and synthesized according to the conformational calculations and the electronic structures of two typical ZnP-C60 derivatives of para-ZnP-C60 (ZnP(p)-C60) and ortho-ZnP-C60 (ZnP(o)-C60). The two derivatives were first investigated by density functional theory (DFT) and ZnP(p)-C60 with a bent conformation was verified to possess a smaller energy gap and better electron-transport ability. Then ZnP(p)-C60 was entrapped in tetraoctylammonium bromide (TOAB) film and modified on glassy carbon electrode (TOAB/ZnP(p)-C60/GCE). The TOAB/ZnP(p)-C60/GCE showed four well-defined quasi-reversible redox couples with extremely fast direct electron transfer and excellent nonenzymatic sensing ability. The electrocatalytic reduction of H2O2 showed a wide linear range from 0.035 to 3.40 mM, with a high sensitivity of 215.6 μA mM(-1) and a limit of detection (LOD) as low as 0.81 μM. The electrocatalytic oxidation of nitrite showed a linear range from 2.0 μM to 0.164 mM, with a sensitivity of 249.9 μA mM(-1) and a LOD down to 1.44 μM. Moreover, the TOAB/ZnP(p)-C60/GCE showed excellent stability and reproducibility, and good testing recoveries for analysis of the nitrite levels of river water and rainwater. The ZnP(p)-C60 can be used as a novel material for the fabrication of nonenzymatic electrochemical sensors.

  13. Wireless Sensing Opportunities for Aerospace Applications

    Directory of Open Access Journals (Sweden)

    William Wilson

    2008-07-01

    Full Text Available Wireless sensors and sensor networks is an emerging technology area with many applications within the aerospace industry. Integrated vehicle health monitoring (IVHM of aerospace vehicles is needed to ensure the safety of the crew and the vehicle, yet often high costs, weight, size and other constraints prevent the incorporation of instrumentation onto spacecraft. This paper presents a few of the areas such as IVHM, where new wireless sensing technology is needed on both existing vehicles as well as future spacecraft. From ground tests to inflatable structures to the International Space Station, many applications could receive benefits from small, low power, wireless sensors. This paper also highlights some of the challenges that need to overcome when implementing wireless sensor networks for aerospace vehicles.

  14. Electrochemical sensors: a powerful tool in analytical chemistry

    Directory of Open Access Journals (Sweden)

    Stradiotto Nelson R.

    2003-01-01

    Full Text Available Potentiometric, amperometric and conductometric electrochemical sensors have found a number of interesting applications in the areas of environmental, industrial, and clinical analyses. This review presents a general overview of the three main types of electrochemical sensors, describing fundamental aspects, developments and their contribution to the area of analytical chemistry, relating relevant aspects of the development of electrochemical sensors in Brazil.

  15. Development of remote electrochemical decontamination for hot cell applications

    International Nuclear Information System (INIS)

    Turner, A.D.; Pottinger, J.S.; Lain, M.J.; Dawson, R.K.; Neville, M.D.; Junkison, A.R.

    1988-01-01

    The paper concerns the development and evaluation of remote electrochemical decontamination systems for metal surfaces, in connection with the decommissioning of nuclear installations. Two types of technique based on the electrochemical dissolution of thin surface layers of the substrate were investigated: immersion of small items in tanks for electroetching and in situ electropolishing. A description is given of the work programme, the progress of work and the results obtained. (U.K.)

  16. Energy-efficient sensing in wireless sensor networks using compressed sensing.

    Science.gov (United States)

    Razzaque, Mohammad Abdur; Dobson, Simon

    2014-02-12

    Sensing of the application environment is the main purpose of a wireless sensor network. Most existing energy management strategies and compression techniques assume that the sensing operation consumes significantly less energy than radio transmission and reception. This assumption does not hold in a number of practical applications. Sensing energy consumption in these applications may be comparable to, or even greater than, that of the radio. In this work, we support this claim by a quantitative analysis of the main operational energy costs of popular sensors, radios and sensor motes. In light of the importance of sensing level energy costs, especially for power hungry sensors, we consider compressed sensing and distributed compressed sensing as potential approaches to provide energy efficient sensing in wireless sensor networks. Numerical experiments investigating the effectiveness of compressed sensing and distributed compressed sensing using real datasets show their potential for efficient utilization of sensing and overall energy costs in wireless sensor networks. It is shown that, for some applications, compressed sensing and distributed compressed sensing can provide greater energy efficiency than transform coding and model-based adaptive sensing in wireless sensor networks.

  17. Synthesis of multilayered structure of nano-dimensional silica glass/reduced graphene oxide for advanced electrochemical applications.

    Science.gov (United States)

    Ghosh, Arnab; Miah, Milon; Majumder, Chinmoy; Bag, Shekhar; Chakravorty, Dipankar; Saha, Shyamal Kumar

    2018-03-28

    During the past few years, intensive research has been carried out to design new functional materials for superior electrochemical applications. Due to low storage capacity and low charge transport, silica based glasses have not yet been investigated for their supercapacitive behavior. Therefore, in the present study, a multilayered structure of silica-based nanoglass and reduced graphene oxide has been designed to remarkably enhance the specific capacitance by exploiting the porosity, large surface area, sufficient dangling bonds in the nanoglass and high electrical conductivity of rGO. The charge transport in the composite structure is also investigated to understand the electrochemical properties. It is found that Simmons tunneling or direct tunneling is the dominant mechanism of charge conduction between the graphene layers via the potential barrier of silica nanoglass phase. We believe that this study will open up a new area in the design of glass-based two-dimensional nanocomposites for superior supercapacitor applications.

  18. Electrochemical preparation of self-doped poly(N-(3-sulfonicpropion) anilide) and its application in sensing ethanol

    International Nuclear Information System (INIS)

    Jiang Chunming; Chen Hui; Kong Jilie

    2009-01-01

    A novel containing sulfonic acid group aniline monomer, N-(3-sulfonicpropion) anilide, was synthesized in three steps and subsequently to be electropolymerized on a glassy carbon electrode (GCE). The resulting self-doped poly(N-(3-sulfonicpropion) anilide) (SPAN/GCE) held 79.5% electrochemical activity when transferred from 0.1 M pH 7.0 PBS to 0.1 M pH 10.0 PBS, indicating its remarkable extension of the redox activity. The SPAN/GCE was characterized by X-ray photoelectron spectroscopy (XPS) and found that 30% of the nitrogen atoms are sulfonated. Preliminary experimental results show that after the immobilization of alcohol dehydrogenase (ADH) on the SPAN/GCE (ADH/SPAN/GCE), the ADH/SPAN/GCE showed good electrocatalytic activity toward the oxidation of ethanol. These reveal that the SPAN/GCE is quite promising in the fields of biosensors, biofuel cells and other bioelectrochemical devices.

  19. A phase mask fiber grating and sensing applications

    Directory of Open Access Journals (Sweden)

    Preecha P. Yupapin

    2003-09-01

    Full Text Available This paper presents an investigation of a fabricated fiber grating device characteristics and its applications, using a phase mask writing technique. The use of a most common UV phase laser (KrF eximer laser, with high intensity light source was focussed to the phase mask for writing on a fiber optic sample. The device (i.e. grating characteristic especially, in sensing application, was investigated. The possibility of using such device for temperature and strain sensors is discussed.

  20. Electrochemical investigation of MoTe2/rGO composite materials for sodium-ion battery application

    Science.gov (United States)

    Panda, Manas Ranjan; Anish Raj, K.; Sarkar, Ananta; Bao, Qiaoliang; Mitra, Sagar

    2018-05-01

    2D layered materials are found to be promising anode materials for renewable energy storage devices like sodium and Li-ion batteries and have become attractive options due to their high specific capacity, abundance and low cost. In this work, we synthesized 2D MoTe2 layers embedded in reduced graphene oxide (rGO) anode material for sodium-ion battery applications. 2D MoTe2 was prepared by a solid-state reaction in vacuum at a temperature of 800 °C. The prepared composite material MoTe2/rGO showed excellent electrochemical performance against the sodium metal. The discharge capacity of MoTe2/rGO was observed to be 280 mAh g-1 at a current rate of 1.0 A g-1 for 100 cycles. rGO plays an important role in embedding the MoTe2 structure, thus improving the electrical and mechanical properties, leading to a superior cycling stability and excellent electrochemical performances of MoTe2 for sodium-ion battery applications.

  1. A review of remote sensing applications for oil palm studies

    Institute of Scientific and Technical Information of China (English)

    Khai Loong Chong; Kasturi Devi Kanniah; Christine Pohl; Kian Pang Tan

    2017-01-01

    Oil palm becomes an increasingly important source of vegetable oil for its production exceeds soybean,sunflower,and rapeseed.The growth of the oil palm industry causes degradation to the environment,especially when the expansion of plantations goes uncontrolled.Remote sensing is a useful tool to monitor the development of oil palm plantations.In order to promote the use of remote sensing in the oil palm industry to support their drive for sustainability,this paper provides an understanding toward the use of remote sensing and its applications to oil palm plantation monitoring.In addition,the existing knowledge gaps are identified and recommendations for further research are given.

  2. Microwave and millimeter-wave remote sensing for security applications

    CERN Document Server

    Nanzer, Jeffrey

    2012-01-01

    Microwave and millimeter-wave remote sensing techniques are fast becoming a necessity in many aspects of security as detection and classification of objects or intruders becomes more difficult. This groundbreaking resource offers you expert guidance in this burgeoning area. It provides you with a thorough treatment of the principles of microwave and millimeter-wave remote sensing for security applications, as well as practical coverage of the design of radiometer, radar, and imaging systems. You learn how to design active and passive sensors for intruder detection, concealed object detection,

  3. Water resources by orbital remote sensing: Examples of applications

    Science.gov (United States)

    Martini, P. R. (Principal Investigator)

    1984-01-01

    Selected applications of orbital remote sensing to water resources undertaken by INPE are described. General specifications of Earth application satellites and technical characteristics of LANDSAT 1, 2, 3, and 4 subsystems are described. Spatial, temporal and spectral image attributes of water as well as methods of image analysis for applications to water resources are discussed. Selected examples are referred to flood monitoring, analysis of water suspended sediments, spatial distribution of pollutants, inventory of surface water bodies and mapping of alluvial aquifers.

  4. Microwave propagation and remote sensing atmospheric influences with models and applications

    CERN Document Server

    Karmakar, Pranab Kumar

    2011-01-01

    Because prevailing atmospheric/troposcopic conditions greatly influence radio wave propagation above 10 GHz, the unguided propagation of microwaves in the neutral atmosphere can directly impact many vital applications in science and engineering. These include transmission of intelligence, and radar and radiometric applications used to probe the atmosphere, among others. Where most books address either one or the other, Microwave Propagation and Remote Sensing: Atmospheric Influences with Models and Applications melds coverage of these two subjects to help readers develop solutions to the problems they present. This reference offers a brief, elementary account of microwave propagation through the atmosphere and discusses radiometric applications in the microwave band used to characterize and model atmospheric constituents, which is also known as remote sensing. Summarizing the latest research results in the field, as well as radiometric models and measurement methods, this book covers topics including: Free sp...

  5. Buffer Film Assisted Growth of Dense MWCNTs on Copper Foils for Flexible Electrochemical Applications

    Directory of Open Access Journals (Sweden)

    Udomdej Pakdee

    2017-01-01

    Full Text Available The novel Inconel buffer films were prepared on copper foils using unbalance direct current (DC magnetron sputtering. These films were employed as buffer layers for supporting the dense growth of multiwalled carbon nanotubes (MWCNTs. Thermal chemical vapor deposition (CVD with metal alloys such as stainless steel (SS type 304 films was considered to synthesize MWCNTs. To understand the effectiveness of these buffer films, the MWCNTs grown on buffer-free layer were carried out as a comparison. The main problem such as the diffusion of catalysts into the oxide layer of metal substrate during the CVD process was solved together with a creation of good electrical contact between substrate and nanotubes. The morphologies, crystallinities, and electrochemical behaviors of MWCNTs grown on Inconel buffer films with 304 SS catalysts revealed the better results for applying in flexible electrochemical applications.

  6. Leveraging of remote sensing and GIS on mapping in urban and regional planning applications

    International Nuclear Information System (INIS)

    Noor, Norzailawati Mohd; Abdullah, Alias; Rosni, Nur Aulia

    2014-01-01

    While remote sensing applications represent a major though still underused source of urban data, the proposed combination between remote sensing and Geo-information System (GIS) in urban and regional planning is not fully explored. In order to measure changes in land use, the need of platform in monitoring, recording, and predicting the changes is necessary for planners and developers. In advance technology of mapping process, remote sensing and GIS as tools for urban planning are already recognised. But, due to lack of implementation and awareness about the benefits of these tools, these terms look unusual. Therefore, this paper reviews the history of remote sensing and GIS in urban applications, technical skills and the challenges, and future development of remote sensing and GIS especially for urban development particularly in developing countries

  7. Single-Molecule Sensing with Nanopore Confinement: from Chemical Reactions to Biological Interactions.

    Science.gov (United States)

    Lin, Yao; Ying, Yi-Lun; Gao, Rui; Long, Yi-Tao

    2018-03-25

    The nanopore can generate an electrochemical confinement for single-molecule sensing which help understand the fundamental chemical principle in nanoscale dimensions. By observing the generated ionic current, individual bond-making and bond-breaking steps, single biomolecule dynamic conformational changes and electron transfer processes that occur within pore can be monitored with high temporal and current resolution. These single-molecule studies in nanopore confinement are revealing information about the fundamental chemical and biological processes that cannot be extracted from ensemble measurements. In this concept, we introduce and discuss the electrochemical confinement effects on single-molecule covalent reactions, conformational dynamics of individual molecules and host-guest interactions in protein nanopores. Then, we extend the concept of nanopore confinement effects to confine electrochemical redox reactions in solid-state nanopores for developing new sensing mechanisms. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Bimetallic Ag-Pd nanoparticles-decorated graphene oxide: a fascinating three-dimensional nanohybrid as an efficient electrochemical sensing platform for vanillin determination

    International Nuclear Information System (INIS)

    Li, Junhua; Feng, Haibo; Li, Jun; Jiang, Jianbo; Feng, Yonglan; He, Lingzhi; Qian, Dong

    2015-01-01

    Highlights: • A 3D Ag-Pd/GO nanohybrid was fabricated via a green and in situ chemical route. • Ag-Pd/GO shows excellent electro-catalytic properties for the oxidation of vanillin. • The 3D hybrid-based sensor shows excellent performances for the vanillin detection. • This proposed method was successfully used to detect vanillin in children’s snacks. - Abstract: In this work, a fascinating hybrid based on Ag-Pd bimetallic nanoparticles-decorated graphene oxide (Ag-Pd/GO) has been successfully synthesized by a green and in situ chemical reduction strategy. The resultant hybrid was particularly characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, ultraviolet-visible spectroscopy and electrochemical techniques. The morphological results illustrate that Ag-Pd nanoparticles in microspheric appearances are highly dispersed and embedded on the GO layers, resulting in a rough surface and three-dimensional (3D) microstructure with a high Ag-Pd content in the matrix. The as-synthesized 3D Ag-Pd/GO hybrid displays distinctly enhanced electrocatalytic activity for the vanillin oxidation in comparison with that of the monometal-decorated GO, revealing a synergistic effect of the matrix GO and the doped bimetallic Ag-Pd. Therefore, the Ag-Pd/GO composite can be used as an enhanced electrochemical sensing platform for the sensitive determination of vanillin, and the fabricated sensor displays a wide detection range of 0.02–45 μmol dm −3 , low detection limit of 5 nmol dm −3 and satisfactory recoveries between 98.8 % and 103.5 %. All the results demonstrate that the 3D hybrids integrated graphene with bimetallic nanoparticles are promising candidates for the development of high-performance electrochemical sensors

  9. Quantitative remote sensing in thermal infrared theory and applications

    CERN Document Server

    Tang, Huajun

    2014-01-01

    This comprehensive technical overview of the core theory of thermal remote sensing and its applications in hydrology, agriculture, and forestry includes a host of illuminating examples and covers everything from the basics to likely future trends in the field.

  10. Liquid–Solid Dual-Gate Organic Transistors with Tunable Threshold Voltage for Cell Sensing

    KAUST Repository

    Zhang, Yu

    2017-10-17

    Liquid electrolyte-gated organic field effect transistors and organic electrochemical transistors have recently emerged as powerful technology platforms for sensing and simulation of living cells and organisms. For such applications, the transistors are operated at a gate voltage around or below 0.3 V because prolonged application of a higher voltage bias can lead to membrane rupturing and cell death. This constraint often prevents the operation of the transistors at their maximum transconductance or most sensitive regime. Here, we exploit a solid–liquid dual-gate organic transistor structure, where the threshold voltage of the liquid-gated conduction channel is controlled by an additional gate that is separated from the channel by a metal-oxide gate dielectric. With this design, the threshold voltage of the “sensing channel” can be linearly tuned in a voltage window exceeding 0.4 V. We have demonstrated that the dual-gate structure enables a much better sensor response to the detachment of human mesenchymal stem cells. In general, the capability of tuning the optimal sensing bias will not only improve the device performance but also broaden the material selection for cell-based organic bioelectronics.

  11. Liquid-Solid Dual-Gate Organic Transistors with Tunable Threshold Voltage for Cell Sensing.

    Science.gov (United States)

    Zhang, Yu; Li, Jun; Li, Rui; Sbircea, Dan-Tiberiu; Giovannitti, Alexander; Xu, Junling; Xu, Huihua; Zhou, Guodong; Bian, Liming; McCulloch, Iain; Zhao, Ni

    2017-11-08

    Liquid electrolyte-gated organic field effect transistors and organic electrochemical transistors have recently emerged as powerful technology platforms for sensing and simulation of living cells and organisms. For such applications, the transistors are operated at a gate voltage around or below 0.3 V because prolonged application of a higher voltage bias can lead to membrane rupturing and cell death. This constraint often prevents the operation of the transistors at their maximum transconductance or most sensitive regime. Here, we exploit a solid-liquid dual-gate organic transistor structure, where the threshold voltage of the liquid-gated conduction channel is controlled by an additional gate that is separated from the channel by a metal-oxide gate dielectric. With this design, the threshold voltage of the "sensing channel" can be linearly tuned in a voltage window exceeding 0.4 V. We have demonstrated that the dual-gate structure enables a much better sensor response to the detachment of human mesenchymal stem cells. In general, the capability of tuning the optimal sensing bias will not only improve the device performance but also broaden the material selection for cell-based organic bioelectronics.

  12. Two dimension (2-D) graphene-based nanomaterials as signal amplification elements in electrochemical microfluidic immune-devices: Recent advances

    Energy Technology Data Exchange (ETDEWEB)

    Hasanzadeh, Mohammad, E-mail: mhmmd_hasanzadeh@yahoo.com [Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz 51664 (Iran, Islamic Republic of); Pharmaceutical Analysis Research Center, Tabriz University of Medical Sciences, Tabriz 51664 (Iran, Islamic Republic of); Shadjou, Nasrin [Department of Nanochemistry, Nano Technology Center and Faculty of Chemistry, Urmia University, Urmia (Iran, Islamic Republic of); Mokhtarzadeh, Ahad [School of Medicine, Gonabad University of Medical Sciences, Gonabad (Iran, Islamic Republic of); Department of Biotechnology, Higher Education Institute of Rab-Rashid, Tabriz (Iran, Islamic Republic of); Pharmaceutical Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of); Ramezani, Mohammad [Pharmaceutical Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of)

    2016-11-01

    Graphene is a 2-D carbon nanomaterial with many distinctive properties that are electrochemically beneficial, such as large surface-to-volume ratio, lowered power usage, high conductivity and electron mobility. Graphene-based electrochemical immune-devices have recently gained much importance for detecting antigens and biomarkers responsible for cancer diagnosis. This review describes fabrication and chemical modification of the surfaces of graphene for immunesensing applications. We also present a comprehensive overview of current developments and key issues in the determination of some biological molecules with particular emphasis on evaluating the models. This review focuses mostly on new developments in the last 5 years in development of chip architecture and integration, different sensing modes that can be used in conjunction with microfluidics, and new applications that have emerged or have been demonstrated; it also aims to point out where future research can be directed to in these areas. - Highlights: • Graphene-based immune-devices have been used for biomedical testing. • Two dimension (2-D) graphene-based immune-devices were discussed. • Current state-of-the-art in graphene-based immune-devices was reflected.

  13. Two dimension (2-D) graphene-based nanomaterials as signal amplification elements in electrochemical microfluidic immune-devices: Recent advances

    International Nuclear Information System (INIS)

    Hasanzadeh, Mohammad; Shadjou, Nasrin; Mokhtarzadeh, Ahad; Ramezani, Mohammad

    2016-01-01

    Graphene is a 2-D carbon nanomaterial with many distinctive properties that are electrochemically beneficial, such as large surface-to-volume ratio, lowered power usage, high conductivity and electron mobility. Graphene-based electrochemical immune-devices have recently gained much importance for detecting antigens and biomarkers responsible for cancer diagnosis. This review describes fabrication and chemical modification of the surfaces of graphene for immunesensing applications. We also present a comprehensive overview of current developments and key issues in the determination of some biological molecules with particular emphasis on evaluating the models. This review focuses mostly on new developments in the last 5 years in development of chip architecture and integration, different sensing modes that can be used in conjunction with microfluidics, and new applications that have emerged or have been demonstrated; it also aims to point out where future research can be directed to in these areas. - Highlights: • Graphene-based immune-devices have been used for biomedical testing. • Two dimension (2-D) graphene-based immune-devices were discussed. • Current state-of-the-art in graphene-based immune-devices was reflected.

  14. Polypyrrole-poly(3,4-ethylenedioxythiophene)-Ag (PPy-PEDOT-Ag) nanocomposite films for label-free electrochemical DNA sensing.

    Science.gov (United States)

    Radhakrishnan, S; Sumathi, C; Umar, Ahmad; Jae Kim, Sang; Wilson, J; Dharuman, V

    2013-09-15

    The electrochemical DNA hybridization sensing of bipolymer polypyrrole and poly(3,4-ethylenedioxythiophene) (PPy-PEDOT) nanotubes functionalized with Ag nanoparticles has been investigated. The bipolymer nanotubes are prepared by simple chemical route and silver nanoparticles (Ag) further deposited over the PPy-PEDOT nanotubes to form PPy-PEDOT-Ag nanocomposite films. DNA labeled at 5'end using 6-mercapto-1-hexhane (HS-ssDNA) is immobilized on the PPy-PEDOT-Ag surface to form PPy-PEDOT-Ag-S-ssDNA and hybridization sensing is done in phosphate buffer. The presence of Ag nanoparticles (~28±5nm) well dispersed in the polymer composite with high surface area, high electrical conductivity and catalytic activity provides desirable microenvironment for the immobilization of probe DNA with controlled orientation leading to increased hybridization efficiency with target DNA. The morphological and structural characterizations by a scanning electron microscope (SEM) and X-ray diffraction (XRD) confirm the nanotube structure of composite polymer while Raman measurements indicate the efficient interactions between the PPy, PEDOT, Ag and HS-ssDNA. The sensor effectively discriminates different target DNA sequences with PPy-PEDOT-Ag-S-ssDNA substrate. The observed dynamic detection range is found between 1×10(-11)M and 1×10(-14)M with the lowest detection limit (3 σ/b) of 5.4×10(-15)M. This observed value is of higher sensitivity than that for MWCNT-Ag, PANi-Au, MWCNT-PPy-Au and PPy-PANi-Au composites reported previously. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Applications of Nonlinear Electrochemical Impedance Spectroscopy (NLEIS)

    KAUST Repository

    Adler, S. B.

    2013-01-01

    This paper reviews the use of nonlinear electrochemical impedance spectroscopy (NLEIS) in the analysis of SOFC electrode reactions. By combining EIS and NLEIS, as well as other independent information about an electrode material, it becomes possible

  16. The woven fiber organic electrochemical transistors based on polypyrrole nanowires/reduced graphene oxide composites for glucose sensing.

    Science.gov (United States)

    Wang, Yuedan; Qing, Xing; Zhou, Quan; Zhang, Yang; Liu, Qiongzhen; Liu, Ke; Wang, Wenwen; Li, Mufang; Lu, Zhentan; Chen, Yuanli; Wang, Dong

    2017-09-15

    Novel woven fiber organic electrochemical transistors based on polypyrrole (PPy) nanowires and reduced graphene oxide (rGO) have been prepared. SEM revealed that the introduction of rGO nanosheets could induce the growth and increase the amount of PPy nanowires. Moreover, it could enhance the electrical performance of fiber transistors. The hybrid transistors showed high on/off ratio of 10 2 , fast switch speed, and long cycling stability. The glucose sensors based on the fiber organic electrochemical transistors have also been investigated, which exhibited outstanding sensitivity, as high as 0.773 NCR/decade, with a response time as fast as 0.5s, a linear range of 1nM to 5μM, a low detection concentration as well as good repeatability. In addition, the glucose could be selectively detected in the presence of ascorbic acid and uric acid interferences. The reliability of the proposed glucose sensor was evaluated in real samples of rabbit blood. All the results indicate that the novel fiber transistors pave the way for portable and wearable electronics devices, which have a promising future for healthcare and biological applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Electrochemical hydrogen isotope sensor based on solid electrolytes

    International Nuclear Information System (INIS)

    Matsumoto, Hiroshige; Hayashi, Hiroyuki; Iwahara, Hiroyasu

    2002-01-01

    An electrochemical sensor of hydrogen isotopes based on solid electrolytes for determining the hydrogen isotope ratios and/or total hydrogen pressures in gases has been developed. This paper describes the methodology of the hydrogen isotope sensing together with experimental results. When hydrogen isotope gases are introduced to an electrochemical cell using a proton-conducting electrolyte (hydrogen isotope cell), the electromotive force (EMF) of the cell agrees with that theoretically estimated. The EMF signals can be used for the determination of the hydrogen isotope ratio in gases if the total hydrogen pressure is predetermined. By supplementary use of an oxide ion conductor cell, both the ratio and total pressure of the hydrogen isotopes can be simultaneously determined. (author)

  18. Graphene/Gold Nano composites-Based Thin Films as an Enhanced Sensing Platform for Voltammetric Detection of Cr(VI) Ions

    International Nuclear Information System (INIS)

    Santhosh, Ch.; Saranya, M.; Ramachandran, R.; Felix, S.; Velmurugan, V.; Grace, A.N.

    2014-01-01

    A highly sensitive and selective Cr(VI) sensor with graphene-based nano composites film as an enhanced sensing platform is reported. The detection of chromium species is a challenging task because of the different possible oxidation states in which the element can occur. The sensing film was developed by homogeneously distributing Au nanoparticles (AuNPs) onto the two-dimensional (2D) graphene nano sheet matrix by electrochemical method. Such nano structured composite film platforms combine the advantages of AuNPs and graph ene nano sheets because of the synergistic effect between them. This effect greatly facilitates the electron-transfer processes and the sensing behavior for Cr(VI) detection, leading to a remarkably improved sensitivity and selectivity. The interference from other heavy metal ions is studied in detail. Such sensing elements are very promising for practical environmental monitoring applications.

  19. Ultra-nanocrystalline diamond nanowires with enhanced electrochemical properties

    International Nuclear Information System (INIS)

    Shalini, Jayakumar; Lin, Yi-Chieh; Chang, Ting-Hsun; Sankaran, Kamatchi Jothiramalingam; Chen, Huang-Chin; Lin, I.-Nan; Lee, Chi-Young; Tai, Nyan-Hwa

    2013-01-01

    The effects of N 2 incorporation in Ar/CH 4 plasma on the electrochemical properties and microstructure of ultra-nanocrystalline diamond (UNCD) films are reported. While the electrical conductivity of the films increased monotonously with increasing N 2 content (up to 25%) in the plasma, the electrochemical behavior was optimized for UNCD films grown in (Ar–10% N 2 )/CH 4 plasma. Transmission electron microscopy showed that the main factor resulting in high conductivity in the films was the formation of needle-like nanodiamond grains and the induction graphite layer encapsulating these grains. The electrochemical process for N 2 -incorporated UNCD films can readily be activated due to the presence of nanographite along the grain boundaries of the films. The formation of needle-like diamond grains was presumably due to the presence of CN species that adhered to the existing nanodiamond clusters, which suppressed radial growth of the nanodiamond crystals, promoting anisotropic growth and the formation of needle-like nanodiamond. The N 2 -incorporated UNCD films outperformed other electrochemical electrode materials, such as boron-doped diamond and glassy carbon, in that the UNCD electrodes could sense dopamine, urea, and ascorbic acid simultaneously in the same mixture with clear resolution

  20. Ultraviolet sensing properties of polyvinyl alcohol-coated aluminium ...

    Indian Academy of Sciences (India)

    Electrochemical; aluminium-doped zinc oxide; PVA-coated; UV sensing. 1. Introduction ... Metal oxides having good optical and structural proper- ties also require good .... close to the calculated defect level due to zinc interstitial. PL spectra of ...

  1. Development of Polymethylmethacrylate Based Composite for Gas Sensing Application

    OpenAIRE

    Devikala, S.; Kamaraj, P.

    2011-01-01

    Gas detection instruments are increasingly needed for industrial health and safety, environmental monitoring and process control. Conductive polymer composites have various industrial applications. The composite prepared by mixing carbon black with polymethylmethacrylate (PMMA) has very good gas sensing applications. The gas sensors based on carbon nanotube/polymer, ceramic and metal oxide composites such as epoxy, polyimide, PMMA / Barium titanate and tin oxide have also been developed. In t...

  2. Development and application of the electrochemical etching technique

    International Nuclear Information System (INIS)

    Sanders, M.E.

    1984-07-01

    This report documents the advances achieved in the development and application of several etched damage track plastic dosimeters that can be used to measure dose-equivalent from neutrons with energies from thermal to 20 MeV. The project was initiated with the design of a rem-responding dosimeter that measured fast (> 1 MeV) neutron dose-equivalent as a function of the damage track density directly induced within the volume of polycarbonate foils amplified by electrochemical etching. Stillwagon (1978) adapted electrochemical etching of polycarbonate foils (ECEPF) to alpha dosimetry and used the technique to determine Pu-239 uptake in human bone. Su (1979) extended the usefulness of the ECEPF neutron dosimetry technique to encompass thermal neutron dose measurement. The thermal neutron dosimeter was composed of an external radiator tablet made of 7 LiF in contact with a polycarbonate foil and utilized the thermal neutron-induced 6 Li(n, α) 3 H reaction to give a dose-equivalent response as a function of alpha track density registered in the detector foil. An intermediate (1 eV-1 MeV) neutron dosimeter was developed and has been shown to give an approximately dose-equivalent response to neutrons with energies from 1 eV to 17 MeV. The intermediate neutron dosimeter consists of 6 LiF-Teflon/CR-39 Polymer foil assembly which is enclosed by a (Cd + In) neutron filter. The neutron dose-equivalent is measured as a variable function of the damage track density registered in the CR-39 detector foil due to alpha particles from the 1/v dependent 6 Li(n, α) 3 H reaction, recoil H, C, O nuclei from neutron-induced elastic scattering within the foil volume, and protons from the 6 Li(n, p) reaction for neutron energies above 2 MeV. 46 figs., 6 tabs

  3. A regenerated electrochemical biosensor for label-free detection of glucose and urea based on conformational switch of i-motif oligonucleotide probe

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhong Feng; Chen, Dong Mei [Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Lei, Jing Lei [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Luo, Hong Qun, E-mail: luohq@swu.edu.cn [Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Li, Nian Bing, E-mail: linb@swu.edu.cn [Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)

    2015-10-15

    Improving the reproducibility of electrochemical signal remains a great challenge over the past decades. In this work, i-motif oligonucleotide probe-based electrochemical DNA (E-DNA) sensor is introduced for the first time as a regenerated sensing platform, which enhances the reproducibility of electrochemical signal, for label-free detection of glucose and urea. The addition of glucose or urea is able to activate glucose oxidase-catalyzed or urease-catalyzed reaction, inducing or destroying the formation of i-motif oligonucleotide probe. The conformational switch of oligonucleotide probe can be recorded by electrochemical impedance spectroscopy. Thus, the difference of electron transfer resistance is utilized for the quantitative determination of glucose and urea. We further demonstrate that the E-DNA sensor exhibits high selectivity, excellent stability, and remarkable regenerated ability. The human serum analysis indicates that this simple and regenerated strategy holds promising potential in future biosensing applications. - Highlights: • Conformational switch of i-motif is used for the detection of glucose and urea. • The sensor can be regenerated. • The proposed method is successfully applied in real sample assay. • Our method is label-free and inexpensive.

  4. Commodity Cluster Computing for Remote Sensing Applications using Red Hat LINUX

    Science.gov (United States)

    Dorband, John

    2003-01-01

    Since 1994, we have been doing research at Goddard Space Flight Center on implementing a wide variety of applications on commodity based computing clusters. This talk is about these clusters and haw they are used on these applications including ones for remote sensing.

  5. Analysis on the status of the application of satellite remote sensing technology to nuclear safeguards

    International Nuclear Information System (INIS)

    Tao Zhangsheng; Zhao Yingjun

    2008-01-01

    Based on the application status of satellite remote sensing technology to nuclear safeguards, advantage of satellite remote sensing technology is analyzed, main types of satellite image used in nuclear safeguards are elaborated and the main application of satellite images is regarded to detect, verify and monitor nuclear activities; verify additional protocol declaration and design information, support performing complementary access inspections; investigate alleged undeclared activities based on open source or the third party information. Application examples of satellite image in nuclear safeguards to analyze nuclear facilities by other countries, the ability of remote sensing technology in nuclear safeguards is discussed. (authors)

  6. Graphene field-effect transistor application for flow sensing

    Directory of Open Access Journals (Sweden)

    Łuszczek Maciej

    2017-01-01

    Full Text Available Microflow sensors offer great potential for applications in microfluidics and lab-on-a-chip systems. However, thermal-based sensors, which are commonly used in modern flow sensing technology, are mainly made of materials with positive temperature coefficients (PTC and suffer from a self-heating effect and slow response time. Therefore, the design of novel devices and careful selection of materials are required to improve the overall flow sensor performance. In this work we propose graphene field-effect transistor (GFET to be used as microflow sensor. Temperature distribution in graphene channel was simulated and the analysis of heat convection was performed to establish the relation between the fluidic flow velocity and the temperature gradient. It was shown that the negative temperature coefficient (NTC of graphene could enable the self-protection of the device and should minimize sensing error from currentinduced heating. It was also argued that the planar design of the GFET sensor makes it suitable for the real application due to supposed mechanical stability of such a construction.

  7. Design of Cyclic Peptide Based Glucose Receptors and Their Application in Glucose Sensing.

    Science.gov (United States)

    Li, Chao; Chen, Xin; Zhang, Fuyuan; He, Xingxing; Fang, Guozhen; Liu, Jifeng; Wang, Shuo

    2017-10-03

    Glucose assay is of great scientific significance in clinical diagnostics and bioprocess monitoring, and to design a new glucose receptor is necessary for the development of more sensitive, selective, and robust glucose detection techniques. Herein, a series of cyclic peptide (CP) glucose receptors were designed to mimic the binding sites of glucose binding protein (GBP), and CPs' sequence contained amino acid sites Asp, Asn, His, Asp, and Arg, which constituted the first layer interactions of GBP. The properties of these CPs used as a glucose receptor or substitute for the GBP were studied by using a quartz crystal microbalance (QCM) technique. It was found that CPs can form a self-assembled monolayer at the Au quartz electrode surface, and the monolayer's properties were characterized by using cyclic voltammetry, electrochemical impedance spectroscopy, and atomic force microscopy. The CPs' binding affinity to saccharide (i.e., galactose, fructose, lactose, sucrose, and maltose) was investigated, and the CPs' sensitivity and selectivity toward glucose were found to be dependent upon the configuration,i.e., the amino acids sequence of the CPs. The cyclic unit with a cyclo[-CNDNHCRDNDC-] sequence gave the highest selectivity and sensitivity for glucose sensing. This work suggests that a synthetic peptide bearing a particular functional sequence could be applied for developing a new generation of glucose receptors and would find huge application in biological, life science, and clinical diagnostics fields.

  8. Novel electrochemical redox-active species: one-step synthesis of polyaniline derivative-Au/Pd and its application for multiplexed immunoassay

    Science.gov (United States)

    Wang, Liyuan; Feng, Feng; Ma, Zhanfang

    2015-11-01

    Electrochemical redox-active species play crucial role in electrochemically multiplexed immunoassays. A one-pot method for synthesizing four kinds of new electrochemical redox-active species was reported using HAuCl4 and Na2PdCl4 as dual oxidating agents and aniline derivatives as monomers. The synthesized polyaniline derivative-Au/Pd composites, namely poly(N-methyl-o-benzenediamine)-Au/Pd, poly(N-phenyl-o-phenylenediamine)-Au/Pd, poly(N-phenyl-p-phenylenediamine)-Au/Pd and poly(3,3’,5,5’-tetramethylbenzidine)-Au/Pd, exhibited electrochemical redox activity at -0.65 V, -0.3 V, 0.12 V, and 0.5 V, respectively. Meanwhile, these composites showed high H2O2 electrocatalytic activity because of the presence of Au/Pd. The as-prepared composites were used as electrochemical immunoprobes in simultaneous detection of four tumor biomarkers (carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA199), carbohydrate antigen 72-4 (CA724), and alpha fetoprotein (AFP)). This immunoassay shed light on potential applications in simultaneous gastric cancer (related biomarkers: CEA, CA199, CA724) and liver cancer diagnosis (related biomarkers: CEA, CA199, AFP). The present strategy to the synthesize redox species could be easily extended to other polymers such as polypyrrole derivatives and polythiophene derivatives. This would be of great significance in the electrochemical detection of more analytes.

  9. Nanostructured core-shell electrode materials for electrochemical capacitors

    Science.gov (United States)

    Jiang, Long-bo; Yuan, Xing-zhong; Liang, Jie; Zhang, Jin; Wang, Hou; Zeng, Guang-ming

    2016-11-01

    Core-shell nanostructure represents a unique system for applications in electrochemical energy storage devices. Owing to the unique characteristics featuring high power delivery and long-term cycling stability, electrochemical capacitors (ECs) have emerged as one of the most attractive electrochemical storage systems since they can complement or even replace batteries in the energy storage field, especially when high power delivery or uptake is needed. This review aims to summarize recent progress on core-shell nanostructures for advanced supercapacitor applications in view of their hierarchical architecture which not only create the desired hierarchical porous channels, but also possess higher electrical conductivity and better structural mechanical stability. The core-shell nanostructures include carbon/carbon, carbon/metal oxide, carbon/conducting polymer, metal oxide/metal oxide, metal oxide/conducting polymer, conducting polymer/conducting polymer, and even more complex ternary core-shell nanoparticles. The preparation strategies, electrochemical performances, and structural stabilities of core-shell materials for ECs are summarized. The relationship between core-shell nanostructure and electrochemical performance is discussed in detail. In addition, the challenges and new trends in core-shell nanomaterials development have also been proposed.

  10. Optical, Nanomechanical and Electrochemical Sensing on a DVD Disc

    DEFF Research Database (Denmark)

    Boisen, Anja

    2014-01-01

    platform in order to study and count larger objects such as cells. In this way it will be possible to analyze a given sample for several parameters simultaneously. Electrodes can also be integrated on the spinning platform [4] and hereby it is possible to perform electrochemical measurements at the same...... combined with sensitive and compact read-out possibilities from optical pick-up heads makes it possible to realize full sample pretreatment and read-out in a both fast and compact manner. References: 1. M. Madou et al., Lab on a CD, Annual Review of Biomedical Engineering, Vol. 8: 601-628, 2016 2. F...

  11. Ultrafast Laser-Based Spectroscopy and Sensing: Applications in LIBS, CARS, and THz Spectroscopy

    Science.gov (United States)

    Leahy-Hoppa, Megan R.; Miragliotta, Joseph; Osiander, Robert; Burnett, Jennifer; Dikmelik, Yamac; McEnnis, Caroline; Spicer, James B.

    2010-01-01

    Ultrafast pulsed lasers find application in a range of spectroscopy and sensing techniques including laser induced breakdown spectroscopy (LIBS), coherent Raman spectroscopy, and terahertz (THz) spectroscopy. Whether based on absorption or emission processes, the characteristics of these techniques are heavily influenced by the use of ultrafast pulses in the signal generation process. Depending on the energy of the pulses used, the essential laser interaction process can primarily involve lattice vibrations, molecular rotations, or a combination of excited states produced by laser heating. While some of these techniques are currently confined to sensing at close ranges, others can be implemented for remote spectroscopic sensing owing principally to the laser pulse duration. We present a review of ultrafast laser-based spectroscopy techniques and discuss the use of these techniques to current and potential chemical and environmental sensing applications. PMID:22399883

  12. Ultrafast Laser-Based Spectroscopy and Sensing: Applications in LIBS, CARS, and THz Spectroscopy

    Directory of Open Access Journals (Sweden)

    Megan R. Leahy-Hoppa

    2010-04-01

    Full Text Available Ultrafast pulsed lasers find application in a range of spectroscopy and sensing techniques including laser induced breakdown spectroscopy (LIBS, coherent Raman spectroscopy, and terahertz (THz spectroscopy. Whether based on absorption or emission processes, the characteristics of these techniques are heavily influenced by the use of ultrafast pulses in the signal generation process. Depending on the energy of the pulses used, the essential laser interaction process can primarily involve lattice vibrations, molecular rotations, or a combination of excited states produced by laser heating. While some of these techniques are currently confined to sensing at close ranges, others can be implemented for remote spectroscopic sensing owing principally to the laser pulse duration. We present a review of ultrafast laser-based spectroscopy techniques and discuss the use of these techniques to current and potential chemical and environmental sensing applications.

  13. Multi-signalling cation sensing behaviour of a bis(pyridin-2-yl methyl)aniline based hetarylazo dye

    International Nuclear Information System (INIS)

    Kaur, Paramjit; Sareen, Divya; Kaur, Mandeep; Singh, Kamaljit

    2013-01-01

    Graphical abstract: The chromogenic and electrochemical behaviour of bis(pyridine-2-yl methyl)aniline based hetarylazo dye gets perturbed in the presence of cations, most effective being Cu 2+ . The conversion of ICT to ICT/MLCT is witnessed by TD-DFT calculations. -- Highlights: •Cation sensing of hetarylazo dye based upon visual, absorption and electrochemical changes is described. •Sensing mechanism is based upon perturbation in intramolecular charge-transfer upon interaction with cations. •Sensing protocol is supported by 1 H NMR studies as well as theoretical calculations. •Hetarylazo dye acts as a multichannel sensor. •Response of the dye towards various cations has also been explored in acidic pH window. -- Abstract: We investigated the cation sensing behaviour of a bis(pyridin-2-yl methyl)aniline appended hetarylazo dye via chromogenic and electrochemical transduction channels. The binding pocket constituting both the pyridyl as well as aniline nitrogen atoms acts as recognition site for the cations and consequent perturbation in the intramolecular charge-transfer prevailing in the dye results in the chromogenic response manifested in the form of hypsochromic shift in the intramolecular charge-transfer band and the attendant naked-eye color changes. The dye exhibits significant changes in its electrochemical behaviour in the presence of cations. The experimental results are also rationalized by time-dependent density functional theory (TD-DFT) calculations

  14. Poly(dimethylsiloxane) cross-linked carbon paste electrodes for microfluidic electrochemical sensing.

    Science.gov (United States)

    Sameenoi, Yupaporn; Mensack, Meghan M; Boonsong, Kanokporn; Ewing, Rebecca; Dungchai, Wijitar; Chailapakul, Orawan; Cropek, Donald M; Henry, Charles S

    2011-08-07

    Recently, the development of electrochemical biosensors as part of microfluidic devices has garnered a great deal of attention because of the small instrument size and portability afforded by the integration of electrochemistry in microfluidic systems. Electrode fabrication, however, has proven to be a major obstacle in the field. Here, an alternative method to create integrated, low cost, robust, patternable carbon paste electrodes (CPEs) for microfluidic devices is presented. The new CPEs are composed of graphite powder and a binder consisting of a mixture of poly(dimethylsiloxane) (PDMS) and mineral oil. The electrodes are made by filling channels molded in previously cross-linked PDMS using a method analogous to screen printing. The optimal binder composition was investigated to obtain electrodes that were physically robust and performed well electrochemically. After studying the basic electrochemistry, the PDMS-oil CPEs were modified with multi-walled carbon nanotubes (MWCNT) and cobalt phthalocyanine (CoPC) for the detection of catecholamines and thiols, respectively, to demonstrate the ease of electrode chemical modification. Significant improvement of analyte signal detection was observed from both types of modified CPEs. A nearly 2-fold improvement in the electrochemical signal for 100 μM dithiothreitol (DTT) was observed when using a CoPC modified electrode (4.0 ± 0.2 nA (n = 3) versus 2.5 ± 0.2 nA (n = 3)). The improvement in signal was even more pronounced when looking at catecholamines, namely dopamine, using MWCNT modified CPEs. In this case, an order of magnitude improvement in limit of detection was observed for dopamine when using the MWCNT modified CPEs (50 nM versus 500 nM). CoPC modified CPEs were successfully used to detect thiols in red blood cell lysate while MWCNT modified CPEs were used to monitor temporal changes in catecholamine release from PC12 cells following stimulation with potassium.

  15. Discussion on the application potential of thermal infrared remote sensing technology in uranium deposits exploration

    International Nuclear Information System (INIS)

    Wang Junhu; Zhang Jielin; Liu Dechang

    2011-01-01

    With the continual development of new thermal infrared sensors and thermal radiation theory, the technology of thermal infrared remote sensing has shown great potential for applications in resources exploration, especially in the field of uranium exploration. The paper makes a systemic summary of the theoretical basis and research status of the thermal infrared remote sensing applications in resources exploration from the surface temperature, thermal inertia and thermal infrared spectrum. What's more, the research objective and the research content of thermal infrared remote sensing in the uranium deposits exploration applications are discussed in detail. Besides, based on the thermal infrared ASTER data, the paper applies this technology to the granite-type uranium deposits in South China and achieves good result. Above all, the practice proves that the thermal infrared remote sensing technology has a good application prospects and particular value in the field of uranium prospecting and will play an important role in the prospecting target of the uranium deposits. (authors)

  16. Femtosecond laser-ablated Fresnel zone plate fiber probe and sensing applications

    Science.gov (United States)

    Tan, Xiaoling; Geng, Youfu; Chen, Yan; Li, Shiguo; Wang, Xinzhong

    2018-02-01

    We investigate the Fresnel zone plate (FZP) inscribed on multimode fiber endface using femtosecond laser ablation and its application in sensing. The mode transmission through fiber tips with FZP is investigated both by the beam propagation method theoretically and by measuring the beam images with a charge-coupled device camera experimentally, which show a good agreement. Such devices are tested for surface-enhanced Raman scattering (SERS) using the aqueous solution of rhodamine 6G under a Raman spectroscopy. The experimental results demonstrate that the SERS signal is enhanced benefiting from focal ability of FZP, which is a promising method for the particular biochemical spectra sensing applications.

  17. Electrochemical applications of room temperature ionic liquids in nuclear fuel cycle

    International Nuclear Information System (INIS)

    Venkatesan, K.A.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2008-01-01

    Applications of room temperature ionic liquids (RTILs) have invaded all branches of science. They are also receiving an upsurge, in recent years, for possible applications in various stages of nuclear fuel cycle. Ionic liquids are compounds composed entirely of ions existing in liquid state and RTILs are ionic liquids molten at temperatures lower than 373 K. RTILs are generally made up of an organic cation and an inorganic or an organic anion. Room temperature ionic liquids have several fascinating properties, which are unique to a particular combination of cation and anion. The properties such as insignificant vapor pressure, amazing ability to dissolve organic and inorganic compounds, wide electrochemical window are the specific advantages when dealing with application of RTILs for reprocessing of spent nuclear fuel. The ionic liquids are regarded as designer or tailor-made solvents as their properties can be tuned for desired application by appropriate cation-anion combinations. An excellent review by Wilkes describes about the historical perspectives of room temperature ionic liquids, pioneers in that area, events and the products delivered till 2001. Furthermore, several comprehensive reviews have been made on room temperature ionic liquids by various authors

  18. TiO2 Nanotubes: Recent Advances in Synthesis and Gas Sensing Properties

    Directory of Open Access Journals (Sweden)

    Giorgio Sberveglieri

    2013-10-01

    Full Text Available Synthesis—particularly by electrochemical anodization-, growth mechanism and chemical sensing properties of pure, doped and mixed titania tubular arrays are reviewed. The first part deals on how anodization parameters affect the size, shape and morphology of titania nanotubes. In the second part fabrication of sensing devices based on titania nanotubes is presented, together with their most notable gas sensing performances. Doping largely improves conductivity and enhances gas sensing performances of TiO2 nanotubes

  19. Gold Cleaning Methods for Electrochemical Detection Applications

    DEFF Research Database (Denmark)

    Fischer, Lee MacKenzie; Tenje, Maria; Heiskanen, Arto

    2009-01-01

    ; hydrochloric acid potential cycling; dimethylamine borane reducing agent solutions at 25 and 65 degrees C; and a dilute form of Aqua Regia. Peak-current potential-differences obtained from cyclic voltammetry and charge transfer resistance obtained from electrochemical impedance spectroscopy, as well as X...

  20. Electrochemical properties of quaternary ammonium salts for electrochemical capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Ue, Makoto; Takeda, Masayuki; Takehara, Masahiro; Mori, Shoichiro [Mitsubishi Chemical Corp., Inashiki, Ibaraki (Japan). Tsukuba Research Center

    1997-08-01

    The limiting reduction and oxidation potentials and electrolytic conductivities of new quaternary ammonium salts were examined for electrochemical capacitor applications, whose anions have already been tested as lithium salts for lithium battery applications. The anodic stability was in the following order BR{sub 4}{sup {minus}} < ClO{sub 4}{sup {minus}} {le} CF{sub 3}SO{sub 3}{sup {minus}} < (CF{sub 3}SO{sub 2}){sub 2}N{sup {minus}} {le} C{sub 4}F{sub 9}SO{sub 3}{sup {minus}} < BF{sub 4}{sup {minus}} < PF{sub 6}{sup {minus}} {le} AsF{sub 6}{sup {minus}} < SbF{sub 6}{sup {minus}}. The electrolytic conductivities of Me{sub 4{minus}n}Et{sub n}N(CF{sub 3}SO{sub 2}){sub 2}N (n = 0--4) were examined in comparison with Me{sub 4{minus}n}Et{sub n}NBF{sub 4} counterparts. These imide salts showed good solubility, relatively high conductivity, and anodic stability in propylene carbonate. Et{sub 4}N(CF{sub 3}SO{sub 2}){sub 2}N was found to be a good supporting salt for low permittivity organic solvents, and it afforded a highly conductive electrolyte system based on the ethylene carbonate-dimethyl carbonate mixed solvent, which is useful for electrochemical capacitor applications.

  1. The Development of Wireless Body Area Network for Motion Sensing Application

    Science.gov (United States)

    Puspitaningayu, P.; Widodo, A.; Yundra, E.; Ramadhany, F.; Arianto, L.; Habibie, D.

    2018-04-01

    The information era has driven the society into the digitally-controlled lifestyle. Wireless body area networks (WBAN) as the specific scope of wireless sensor networks (WSN) is consistently growing into bigger applications. Currently, people are able to monitor their medical parameters by simply using small electronics devices attached to their body and connected to the authorities. On top of that, this time, smart phones are typically equipped with sensors such as accelerometer, gyroscope, barometric pressure, heart rate monitor, etc. It means that the sensing yet the signal processing can be performed by a single device. Moreover, Android opens lot wider opportunities for new applications as the most popular open-sourced smart phone platform. This paper is intended to show the development of motion sensing application which focused on analysing data from accelerometer and gyroscope. Beside reads the sensors, this application also has the ability to convert the sensors’ numerical value into graphs.

  2. REMOTE SENSING APPLICATIONS WITH HIGH RELIABILITY IN CHANGJIANG WATER RESOURCE MANAGEMENT

    Directory of Open Access Journals (Sweden)

    L. Ma

    2018-04-01

    Full Text Available Remote sensing technology has been widely used in many fields. But most of the applications cannot get the information with high reliability and high accuracy in large scale, especially for the applications using automatic interpretation methods. We have designed an application-oriented technology system (PIR composed of a series of accurate interpretation techniques,which can get over 85 % correctness in Water Resource Management from the view of photogrammetry and expert knowledge. The techniques compose of the spatial positioning techniques from the view of photogrammetry, the feature interpretation techniques from the view of expert knowledge, and the rationality analysis techniques from the view of data mining. Each interpreted polygon is accurate enough to be applied to the accuracy sensitive projects, such as the Three Gorge Project and the South - to - North Water Diversion Project. In this paper, we present several remote sensing applications with high reliability in Changjiang Water Resource Management,including water pollution investigation, illegal construction inspection, and water conservation monitoring, etc.

  3. Remote Sensing Applications with High Reliability in Changjiang Water Resource Management

    Science.gov (United States)

    Ma, L.; Gao, S.; Yang, A.

    2018-04-01

    Remote sensing technology has been widely used in many fields. But most of the applications cannot get the information with high reliability and high accuracy in large scale, especially for the applications using automatic interpretation methods. We have designed an application-oriented technology system (PIR) composed of a series of accurate interpretation techniques,which can get over 85 % correctness in Water Resource Management from the view of photogrammetry and expert knowledge. The techniques compose of the spatial positioning techniques from the view of photogrammetry, the feature interpretation techniques from the view of expert knowledge, and the rationality analysis techniques from the view of data mining. Each interpreted polygon is accurate enough to be applied to the accuracy sensitive projects, such as the Three Gorge Project and the South - to - North Water Diversion Project. In this paper, we present several remote sensing applications with high reliability in Changjiang Water Resource Management,including water pollution investigation, illegal construction inspection, and water conservation monitoring, etc.

  4. Electrochemical formation of InP porous nanostructures and its application to amperometric chemical sensors

    International Nuclear Information System (INIS)

    Sato, Taketomo; Mizohata, Akinori; Fujino, Toshiyuki; Hashizume, Tamotsu

    2008-01-01

    In this paper, we report the electrochemical formation of the InP porous nanostructures and their feasibility for the application to the amperometric chemical sensors. Our two step electrochemical process consists of the pore formation on a (001) n-type InP substrate and the subsequent etching of pore walls caused by changing the polarity of the InP electrode in a HCl-based electrolyte. By applying the anodic bias to the InP electrode, the high-density array of uniform nanopores was formed on the surface. Next, the cathodic bias was applied to the porous sample to reduce the wall thickness by cathodic decomposition of InP, where the thickness of InP nanowall decreased uniformly along the entire depth of the porous layer. From the amperometric measurements of the porous electrode, it was found that the electrocatalytic activity was much higher than that of the planar electrode. Furthermore, the current sensitivity for the H 2 O 2 detection was much enhanced after the cathodic decomposition process. The InP porous nanostructure formed by the present process is one of the promising structures for the application to the semiconductor-based bio/chemical sensors. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Application of alternating current for dimensionally electrochemical machining

    International Nuclear Information System (INIS)

    Kacheev, M.K.; Kovalev, L.M.

    1978-01-01

    The results of comparative experimental investigations in dimensionally electrochemical machining of 1Kh18N9T steel using alternating and direct currents are presented. The effect of the electrolyte rate in the inter-electrode clearance, electrode voltage and oscillation amplitude of the electrode-tool on the metal output from the electrodes and the relief of the machined surface is studied. It is shown that the a.c. electrochemical machining permits to achieve the greater dimensional accuracy than the d.c. machining when choosing the proper voltage and electrolyte composition. It is connected with the fact that the prevailing part of the metal output is obtained in the impulse-asymmetrical regime when the inter-electrode clearance is minimum

  6. Selective Electrochemical Detection of Epinephrine Using Gold Nanoporous Film

    Directory of Open Access Journals (Sweden)

    Dina M. Fouad

    2016-01-01

    Full Text Available Epinephrine (EP is one of the important catecholamine neurotransmitters that play an important role in the mammalian central nervous system. Therefore, it is necessary to determine the change of its concentrations. Nanoporous materials have wide applications that include catalysis, energy storages, environmental pollution control, wastewater treatment, and sensing applications. These unique properties could be attributable to their high surface area, a large pore volume, and uniform pore sizes. A gold nanoporous layer modified gold electrode was prepared and applied for the selective determination of epinephrine neurotransmitter at low concentration in the presence of several other substances including ascorbic acid (AA and uric acid (UA. The constructed electrode was characterized using scanning electron microscopy and cyclic voltammetry. The resulting electrode showed a selective detection of epinephrine with the interferences of dopamine and uric acid over a wide linear range (from 50 μM to 1 mM. The coverage of gold nanoporous on the surface of gold electrode represents a promising electrochemical sensor with high selectivity and sensitivity.

  7. Synthesis of new copper nanoparticle-decorated anchored type ligands: Applications as non-enzymatic electrochemical sensors for hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Ensafi, Ali A., E-mail: Ensafi@cc.iut.ac.ir; Zandi-Atashbar, N.; Ghiaci, M.; Taghizadeh, M.; Rezaei, B.

    2015-02-01

    In this work, copper nanoparticles (CuNPs) decorated on two new anchored type ligands were utilized to prepare two electrochemical sensors. These ligands are made from bonding amine chains to silica support including SiO{sub 2}–pro–NH{sub 2} (compound I) and SiO{sub 2}–pro–NH–cyanuric–NH{sub 2} (compound II). The morphology of synthesized CuNPs was characterized by transmission electron microscopy (TEM). The nano-particles were in the range of 13–37 nm with the average size of 23 nm. These materials were used to modify carbon paste electrode. Different electrochemical techniques, including cyclic voltammetry, electrochemical impedance spectroscopy and hydrodynamic chronoamperometry, were used to study the sensor behavior. These electrochemical sensors were used as a model for non-enzymatic detection of hydrogen peroxide (H{sub 2}O{sub 2}). To evaluate the abilities of the modified electrodes for H{sub 2}O{sub 2} detection, the electrochemical signals were compared in the absence and presence of H{sub 2}O{sub 2}. From them, two modified electrodes showed significant responses vs. H{sub 2}O{sub 2} addition. The amperograms illustrated that the sensors were selective for H{sub 2}O{sub 2} sensing with linear ranges of 5.14–1250 μmol L{sup −1} and 1.14–1120 μmol L{sup −1} with detection limits of 0.85 and 0.27 μmol L{sup −1} H{sub 2}O{sub 2}, sensitivities of 3545 and 11,293 μA mmol{sup −1} L and with response times less than 5 s for I/CPE and II/CPE, respectively. As further verification of the selected sensor, H{sub 2}O{sub 2} contained in milk sample was analyzed and the obtained results were comparable with the ones from classical control titration method. - Highlights: • Copper nanoparticles decorating on two new anchored type ligands were prepared. • Ligands are bonding to silica support as SiO{sub 2}–pro–NH{sub 2} and SiO{sub 2}–pro–NH–cyanuric–NH{sub 2}. • These materials were used as electrochemical sensors for H

  8. Thermophysical and Electrochemical Properties of Ethereal Functionalised Cyclic Alkylammonium-based Ionic Liquids as Potential Electrolytes for Electrochemical Applications.

    Science.gov (United States)

    Neale, Alex R; Murphy, Sinead; Goodrich, Peter; Hardacre, Christopher; Jacquemin, Johan

    2017-08-05

    A series of hydrophobic room temperature ionic liquids (ILs) based on ethereal functionalised pyrrolidinium, piperidinium and azepanium cations bearing the bis[(trifluoromethyl)sulfonyl]imide, [TFSI] - , anion were synthesized and characterized. Their physicochemical properties such as density, viscosity and electrolytic conductivity, and thermal properties including phase transition behaviour and decomposition temperature have been measured. All of the ILs showed low melting point, low viscosity and good conductivity and the latter properties have been discussed in terms of the IL fragility, an important electrolyte feature of the transport properties of glass-forming ILs. Furthermore, the studied [TFSI] - -based ILs generally exhibit good electrochemical stabilities and, by coupling electrochemical experiments and DFT calculations, the effect of ether functionalisation at the IL cation on the electrochemical stability of the IL is discussed. Preliminary investigations into the Li-redox chemistry at a Cu working electrode are also reported as a function of ether-functionality within the pyrrolidinium-based IL family. Overall, the results show that these ionic liquids are suitable for electrochemical devices such as battery systems, fuel cells or supercapacitors. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  9. Application of N-doped graphene modified carbon ionic liquid electrode for direct electrochemistry of hemoglobin.

    Science.gov (United States)

    Sun, Wei; Dong, Lifeng; Deng, Ying; Yu, Jianhua; Wang, Wencheng; Zhu, Qianqian

    2014-06-01

    Nitrogen-doped graphene (NG) was synthesized and used for the investigation on direct electrochemistry of hemoglobin (Hb) with a carbon ionic liquid electrode as the substrate electrode. Due to specific characteristics of NG such as excellent electrocatalytic property and large surface area, direct electron transfer of Hb was realized with enhanced electrochemical responses appearing. Electrochemical behaviors of Hb on the NG modified electrode were carefully investigated with the electrochemical parameters calculated. The Hb modified electrode exhibited excellent electrocatalytic reduction activity toward different substrates, such as trichloroacetic acid and H2O2, with wider dynamic range and lower detection limit. These findings show that NG can be used for the preparation of chemically modified electrodes with improved performance and has potential applications in electrochemical sensing. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Characterization of an electrochemical mercury sensor using alternating current, cyclic, square wave and differential pulse voltammetry

    Energy Technology Data Exchange (ETDEWEB)

    Guerreiro, Gabriela V.; Zaitouna, Anita J.; Lai, Rebecca Y., E-mail: rlai2@unl.edu

    2014-01-31

    Graphical abstract: -- Highlights: •An electrochemical Hg(II) sensor based on T–Hg(II)–T sensing motif was fabricated. •A methylene blue-modified DNA probe was used to fabricate the sensor. •Sensor performance was evaluated using ACV, CV, SWV, and DPV. •The sensor behaves as a “signal-off” sensor in ACV and CV. •The sensor behaves as either a “signal-on” or “signal-off” sensor in SWV and DPV. -- Abstract: Here we report the characterization of an electrochemical mercury (Hg{sup 2+}) sensor constructed with a methylene blue (MB)-modified and thymine-containing linear DNA probe. Similar to the linear probe electrochemical DNA sensor, the resultant sensor behaved as a “signal-off” sensor in alternating current voltammetry and cyclic voltammetry. However, depending on the applied frequency or pulse width, the sensor can behave as either a “signal-off” or “signal-on” sensor in square wave voltammetry (SWV) and differential pulse voltammetry (DPV). In SWV, the sensor showed “signal-on” behavior at low frequencies and “signal-off” behavior at high frequencies. In DPV, the sensor showed “signal-off” behavior at short pulse widths and “signal-on” behavior at long pulse widths. Independent of the sensor interrogation technique, the limit of detection was found to be 10 nM, with a linear dynamic range between 10 nM and 500 nM. In addition, the sensor responded to Hg{sup 2+} rather rapidly; majority of the signal change occurred in <20 min. Overall, the sensor retains all the characteristics of this class of sensors; it is reagentless, reusable, sensitive, specific and selective. This study also highlights the feasibility of using a MB-modified probe for real-time sensing of Hg{sup 2+}, which has not been previously reported. More importantly, the observed “switching” behavior in SWV and DPV is potentially generalizable and should be applicable to most sensors in this class of dynamics-based electrochemical biosensors.

  11. Grid workflow validation using ontology-based tacit knowledge: A case study for quantitative remote sensing applications

    Science.gov (United States)

    Liu, Jia; Liu, Longli; Xue, Yong; Dong, Jing; Hu, Yingcui; Hill, Richard; Guang, Jie; Li, Chi

    2017-01-01

    Workflow for remote sensing quantitative retrieval is the ;bridge; between Grid services and Grid-enabled application of remote sensing quantitative retrieval. Workflow averts low-level implementation details of the Grid and hence enables users to focus on higher levels of application. The workflow for remote sensing quantitative retrieval plays an important role in remote sensing Grid and Cloud computing services, which can support the modelling, construction and implementation of large-scale complicated applications of remote sensing science. The validation of workflow is important in order to support the large-scale sophisticated scientific computation processes with enhanced performance and to minimize potential waste of time and resources. To research the semantic correctness of user-defined workflows, in this paper, we propose a workflow validation method based on tacit knowledge research in the remote sensing domain. We first discuss the remote sensing model and metadata. Through detailed analysis, we then discuss the method of extracting the domain tacit knowledge and expressing the knowledge with ontology. Additionally, we construct the domain ontology with Protégé. Through our experimental study, we verify the validity of this method in two ways, namely data source consistency error validation and parameters matching error validation.

  12. Binary CuO/Co{sub 3}O{sub 4} nanofibers for ultrafast and amplified electrochemical sensing of fructose

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yang [College of Chemistry, Jilin University, Changchun 130012 (China); Wang Wen [Yantai Wanhua Polyurethanes Co., Ltd., Shandong 264002 (China); Song Wenbo, E-mail: wbsong@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130012 (China)

    2011-11-30

    Highlights: > Binary CuO/Co{sub 3}O{sub 4} nanofiber as active electrode material. > Dramatically enhanced catalytic activity and direct fructose detection. > Significantly lowered overpotential, ultrafast (1 s) and sensitive (18.988 {mu}A mM{sup -1}) response. - Abstract: Cobalt oxide-doped copper oxide composite nanofibers (CCNFs) were successfully achieved via electrospinning followed by thermal treatment processes and then exploited as active electrode material for direct enzyme-free fructose detection. The morphology and the structure of as-prepared samples were investigated by X-ray diffraction spectrum (XRD) and scanning electron microscopy (SEM). The electrocatalytic activity of CCNFs films towards fructose oxidation and sensing performances were evaluated by conventional electrochemical techniques. Cyclic voltammetry (CV) and chronoamperometry (I-t) revealed the distinctly enhanced sensing properties towards fructose compared to pure copper oxide nanofibers (CNFs), i.e., showing significantly lowered overpotential of 0.30 V, ultrafast (1 s) and ultrasensitive (18.988 {mu}A mM{sup -1}) current response in a wide linear range of 1.0 x 10{sup -5} M to 6.0 x 10{sup -3} M with satisfied reproducibility and stability, which could be ascribed to the synergic catalytic effect of the binary CuO/Co{sub 3}O{sub 4} composite nanofibers and the highly porous three-dimensional network films structure of the CCNFs. In addition, a good selectivity for fructose detection was achieved. Results in this work demonstrated that CCNFs is one of the promising catalytic electrode materials for enzymeless fructose sensor fabrication.

  13. Growth of 2D Materials and Application in Electrochemical Energy Conversion

    Science.gov (United States)

    Ye, Gonglan

    The discovery of graphene in 2004 has generated numerous interests among scientists for graphene's versatile potentials. The enthusiasm for graphene has recently been extended to other members of two-dimensional (2D) materials for applications in electronics, optoelectronics, and catalysis. Different from graphene, atomically-thin transition metal dichalcogenides (TMDs) have varied band gaps and would benefit for applications in the semiconductor industry. One of the promising applications of 2D TMDs is for 2D integrated circuits to replace current Si based electronics. In addition to electronic applications, 2D materials are also good candidates for electrochemical energy storage and conversion due to their large surface area and atomic thickness. This thesis mainly focuses on the synthesis of 2D materials and their application in energy conversion. Firstly, we focus on the synthesis of two-dimensional Tin Disulfide (SnS2). SnS2 is considered to be a novel material in 2D family. 2D SnS2 has a large band gap ( 2.8 eV) and high carrier mobility, which makes it a potential applicant for electronics. Monolayer SnS2 with large scale and high crystal quality was successfully synthesized by chemical vapor deposition (CVD), and its performance as a photodetector was examined. The next chapter demonstrated a generic method for growing millimeter-scale single crystals as well as wafer-scale thin films of TMDs. This generic method was obtained by studying the precursors' behavior and the flow dynamics during the CVD process of growing MoSe2, and was extended to other TMD layers such as millimeter-scale WSe2 single crystals. Understanding the growth processes of high quality large area monolayers of TMDs is crucial for further fundamental research as well as future development for scalable complex electronics. Besides the synthesis of 2D materials with high qualities, we further explored the relationship between defects and electrochemical properties. By directly observing

  14. Development of the electrochemically regenerable carbon dioxide absorber for portable life support system application

    Science.gov (United States)

    Woods, R. R.; Heppner, D. B.; Marshall, R. D.; Quattrone, P. D.

    1979-01-01

    As the length of manned space missions increase, more ambitious extravehicular activities (EVAs) are required. For the projected longer mission the use of expendables in the portable life support system (PLSS) will become prohibited due to high launch weight and volume requirements. Therefore, the development of a regenerable CO2 absorber for the PLSS application is highly desirable. The paper discusses the concept, regeneration mechanism, performance, system design, and absorption/regeneration cycle testing of a most promising concept known as ERCA (Electrochemically Regenerable CO2 Absorber). This concept is based on absorbing CO2 into an alkaline absorbent similar to LiOH. The absorbent is an aqueous solution supported in a porous matrix which can be electrochemically regenerated on board the primary space vehicle. With the metabolic CO2 recovery the ERCA concept results in a totally regenerable CO2 scrubber. The ERCA test hardware has passed 200 absorption/regeneration cycles without performance degradation.

  15. Photonic Crystal Fibers for Sensing Applications

    Directory of Open Access Journals (Sweden)

    Ana M. R. Pinto

    2012-01-01

    Full Text Available Photonic crystal fibers are a kind of fiber optics that present a diversity of new and improved features beyond what conventional optical fibers can offer. Due to their unique geometric structure, photonic crystal fibers present special properties and capabilities that lead to an outstanding potential for sensing applications. A review of photonic crystal fiber sensors is presented. Two different groups of sensors are detailed separately: physical and biochemical sensors, based on the sensor measured parameter. Several sensors have been reported until the date, and more are expected to be developed due to the remarkable characteristics such fibers can offer.

  16. Carbon nanotubes-functionalized urchin-like In2S3 nanostructure for sensitive and selective electrochemical sensing of dopamine

    International Nuclear Information System (INIS)

    Yang, Z.; Huang, X.; Li, J.; Zhang, Y.; Yu, S.; Xu, Q.; Hu, X.

    2012-01-01

    Urchin-like In 2 S 3 nanostructures were functionalized with multi-walled carbon nanotubes (MWCNTs) and deposited on a glassy carbon electrode (GCE) to obtain a new kind of sensor for dopamine (DA). The new electrode was characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, cyclic voltammetry and differential pulse voltammetry. It is found that the current response toward DA is significantly enhanced compared to that of a bare GCE or a GCE modified with MWCNTs. The peak separation between DA and ascorbic acid (AA) is up to 225 mV. The new electrode also has improved selectivity for DA over AA compared to the bare electrode. The new DA sensor has a wide linear range (0.5-300 μM), high sensitivity (594.9 μA mM -1 cm -2 ) and low detection limit (0.1 μM). CNTs wrapped on urchin-like nanostructures remarkable improve its electrocatalytic activity and thus provide a promising strategy to develop excellent composite materials for electrochemical sensing. (author)

  17. Enhanced catalytic and dopamine sensing properties of electrochemically reduced conducting polymer nanocomposite doped with pure graphene oxide.

    Science.gov (United States)

    Wang, Wenting; Xu, Guiyun; Cui, Xinyan Tracy; Sheng, Ge; Luo, Xiliang

    2014-08-15

    Significantly enhanced catalytic activity of a nanocomposite composed of conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) doped with graphene oxide (GO) was achieved through a simple electrochemical reduction process. The nanocomposite (PEDOT/GO) was electrodeposited on an electrode and followed by electrochemical reduction, and the obtained reduced nanocomposite (PEDOT/RGO) modified electrode exhibited lowered electrochemical impedance and excellent electrocatalytic activity towards the oxidation of dopamine. Based on the excellent catalytic property of PEDOT/RGO, an electrochemical sensor capable of sensitive and selective detection of DA was developed. The fabricated sensor can detect DA in a wide linear range from 0.1 to 175μM, with a detection limit of 39nM, and it is free from common interferences such as uric acid and ascorbic acid. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Synergetic enhancement of gold nanoparticles and 2-mercaptobenzothiazole as highly-sensitive sensing strategy for tetrabromobisphenol A

    Science.gov (United States)

    Chen, Xuerong; Ji, Liudi; Zhou, Yikai; Wu, Kangbing

    2016-05-01

    Various gold nanoparticles (AuNPs) were in-situ prepared on the electrode surface through electrochemical reduction under different potentials such as -0.60, -0.50, -0.40, -0.30 and -0.20 V. The reduction potentials heavily affect the surface morphology and electrochemical activity of AuNPs such as effective area and catalytic ability, as confirmed using atomic force microscopy and electrochemical impedance spectroscopy. The electrochemical behaviors of tetrabromobisphenol A (TBBPA), a widely-existed pollutant with severe adverse health effects, were studied. The oxidation activity of TBBPA enhances obviously on the surface of AuNPs, and the signal improvements of TBBPA show difference on the prepared AuNPs. Interestingly, the existence of 2-mercaptobenzothiazole (MBT) further improves the oxidation signals of TBBPA on AuNPs. The synergetic enhancement effects of AuNPs and MBT were studied using cyclic voltammetry and chronocoulometry. The numerous nano-scaled gold particles together with the strong hydrophobic interaction between TBBPA and the assembled MBT on AuNPs jointly provide highly-effective accumulation for TBBPA. As a result, a sensitive and simple electrochemical method was developed for the direct determination of TBBPA, with detection limit of 0.12 μg L-1 (0.22 nM). The practical applications in water samples manifest that this new sensing system is accurate and feasible.

  19. Gold/diamond nanohybrids for quantum sensing applications

    International Nuclear Information System (INIS)

    Tsai, Pei-Chang; Chen, Oliver Y.; Tzeng, Yan-Kai; Hui, Yuen Yung; Chang, Ming-Shien; Guo, Jiun You; Wu, Chih-Che; Chang, Huan-Cheng

    2015-01-01

    Recent advances in quantum technology have demonstrated the potential use of negatively charged nitrogen-vacancy (NV - ) centers in diamond for temperature and magnetic sensing at sub-cellular levels. Fluorescent nanodiamonds (FNDs) containing high-density ensembles of NV - centers are appealing for such applications because they are inherently biocompatible and non-toxic. Here, we show that FNDs conjugated with gold nanorods (GNRs) are useful as a combined nanoheater and nanothermometer for highly localized hyperthermia treatment using near-infrared (NIR) lasers as the heating source. A temperature rise of ∝10 K can be readily achieved at a NIR laser power of 0.4 mW in cells. The technique is compatible with the presence of static magnetic fields and allows for simultaneous temperature and magnetic sensing with nanometric spatial resolution. To elucidate the nanoscale heating process, numerical simulations are conducted with finite element analysis, providing an important guideline for the use of this new tool for active and high-precision control of temperature under diverse environmental conditions. (orig.)

  20. Application of Nd/sup 3+/-doped silica fibers to radiation sensing devices

    International Nuclear Information System (INIS)

    Imamura, K.; Suzuki, T.; Gozen, T.; Tanaka, H.; Okamoto, S.

    1987-01-01

    Applications of rare-earth-ion-doped optical fibers to radiation sensing devices have been studied. It was revealed that rare-earth-ion-doped optical fibers are highly sensitive to radioactive rays such as gamma ray and thermal neutron flux and that they have little dependence on ambient temperature and optical power. An experimental distributed radiation sensing system incorporating Nd/sup 3+/-doped optical fibers, radiation resistant optical fibers and an OTDR was made and tested. The results proved that the distributed sensing system is practically adaptable to the measurement of the radioactive rays

  1. Influence of electrochemical pre-treatment on highly reactive carbon nitride thin films deposited on stainless steel for electrochemical applications

    International Nuclear Information System (INIS)

    Benchikh, A.; Debiemme-Chouvy, C.; Cachet, H.; Pailleret, A.; Saidani, B.; Beaunier, L.; Berger, M.H.

    2012-01-01

    In this work, a-CNx films prepared by DC magnetron sputtering on stainless steel substrate have been investigated as electrode materials. While their wide potential window was confirmed as a property shared by boron doped diamond (BDD) electrodes, their electrochemical activity with respect to fast and reversible redox systems, [Ru(NH 3 ) 6 ] 3+/2+ , [Fe(CN) 6 ] 3−/4− and [IrCl 6 ] 2−/3− , was assessed by Electrochemical Impedance Spectroscopy (EIS) after cathodic or anodic electrochemical pre-treatments or for as grown samples. It was shown for the three systems that electrochemical reactivity of the a-CNx films was improved after the cathodic pre-treatment and degraded after the anodic one, the apparent heterogeneous rate constant k 0app being decreased by at least one order of magnitude for the latter case. A high k 0app value of 0.11 cm s −1 for [IrCl 6 ] 2−/3− was obtained, close to the highest values found for BDD electrodes.

  2. Introducing molecular selectivity in rapid impedimetric sensing of phthalates

    KAUST Repository

    Zia, Asif I.

    2014-05-01

    This research article reports a real-time and non-invasive detection technique for phthalates in liquids by Electrochemical Impedance Spectroscopy (EIS), incorporating molecular imprinting technique to introduce selectivity for the phthalate molecule in the detection system. A functional polymer with Bis (2-ethylhexyl) phthalate (DEHP) template was immobilized on the sensing surface of the inter-digital (ID) capacitive sensor with sputtered gold sensing electrodes fabricated over a native layer of silicon dioxide on a single crystal silicon substrate. Various concentrations (10 to 200 ppm) of DEHP in deionized MilliQ water were exposed to the sensor surface functionalized with molecular imprinted polymer (MIP) in order to capture the analyte molecule, hence introducing molecular selectivity to the testing system. Impedance spectra were obtained using EIS in order to determine sample conductance for evaluation of phthalate concentration in the solution. Electrochemical Spectrum Analyzer algorithm was used to deduce equivalent circuit and equivalent component parameters from the experimentally obtained impedance spectra employing Randle\\'s cell model curve fitting technique. Experimental results confirmed that the immobilization of the functional polymer on sensing surface introduces selectivity for phthalates in the sensing system. The results were validated by testing the samples using High Performance Liquid Chromatography (HPLC-DAD). © 2014 IEEE.

  3. Ultrasensitive molecularly imprinted electrochemical sensor based on magnetism graphene oxide/β-cyclodextrin/Au nanoparticles composites for chrysoidine analysis

    International Nuclear Information System (INIS)

    Wang, Xiaojiao; Li, Xiangjun; Luo, Chuannan; Sun, Min; Li, Leilei; Duan, Huimin

    2014-01-01

    Highlights: • Synthesis and application of MGO/β-CD@AuNPs as a sensor for chrysoidine analysis. • The synthesized polymer had a laminar structure with high surface. • The propose sensor showed high selectivity and good sensitivity. - Abstract: A imprinted electrochemical sensor based on glassy carbon electrode (GCE) for ultrasensitive detection of chrysoidine was fabricated. A GCE was modified by magnetic graphene oxide/β-cyclodextrin/gold nanoparticles composites (MGO/β-CD@AuNPs). The sensing surface area and electronic transmission rate were increased, which was benefited from the distribution property of MGO/β-CD@AuNPs. The MGO/β-CD@AuNPs composite improved electrochemical response and sensitivity of the sensor. The molecularly imprinted electrochemical sensor was prepared by electropolymerization on modified electrode. Chrysoidine and pyrrole were used as template molecule and functional monomer, respectively. Under the optimization experimental conditions, the electrochemical sensor exhibited excellent analytical performance: the detection of chrysoidine ranged from 5.0 × 10 −8 mol/L to 5.0 × 10 −6 mol/L with the detection limit of 1.7 × 10 −8 mol/L. The sensor was applied to determine chrysoidine in spiked water samples and showed high selectivity, good sensitivity and acceptable reproducibility. The proposed method provides a promising platform for trace amount detection of other food additives

  4. Electrochemical behaviour of titanium coated stainless steel by r.f. sputtering in synthetic sweat solutions for electrode applications

    International Nuclear Information System (INIS)

    Fonseca, C.; Vaz, F.; Barbosa, M.A.

    2004-01-01

    The r.f. sputtering technique was used to deposit titanium thin films on stainless steel substrates, aiming at the application of the coated samples as skin contact materials for 'dry' active electrodes. In this work the electrochemical behaviour of the coated samples was investigated in synthetic sweat solutions and their performance was compared with that of uncoated stainless steel and bulk titanium. The characterisation of the samples was carried out by electrochemical techniques and scanning electron microscopy. The coated samples displayed corrosion resistance values in synthetic sweat solutions much higher than stainless steel samples and of the same order of the values measured for bulk titanium in the same conditions

  5. China national space remote sensing infrastructure and its application

    Science.gov (United States)

    Li, Ming

    2016-07-01

    Space Infrastructure is a space system that provides communication, navigation and remote sensing service for broad users. China National Space Remote Sensing Infrastructure includes remote sensing satellites, ground system and related systems. According to the principle of multiple-function on one satellite, multiple satellites in one constellation and collaboration between constellations, series of land observation, ocean observation and atmosphere observation satellites have been suggested to have high, middle and low resolution and fly on different orbits and with different means of payloads to achieve a high ability for global synthetically observation. With such an infrastructure, we can carry out the research on climate change, geophysics global surveying and mapping, water resources management, safety and emergency management, and so on. I This paper gives a detailed introduction about the planning of this infrastructure and its application in different area, especially the international cooperation potential in the so called One Belt and One Road space information corridor.

  6. Electrochemical co-reduction synthesis of graphene/nano-gold composites and its application to electrochemical glucose biosensor

    International Nuclear Information System (INIS)

    Wang, Xiaolin; Zhang, Xiaoli

    2013-01-01

    Graphical abstract: - Highlights: • Graphene/nano-Au composite was synthesized by electrochemical co-reduction method in one step. • Glucose oxidase achieves direct electrochemistry on the graphene/nano-Au composite film. • The glucose biosensor shows a high sensitivity of 56.93 μA mM −1 cm −2 toward glucose. • Glucose was detected with a wide linear range and low detection limit. - Abstract: A simple, green and controllable approach was employed for electrochemical synthesize of the graphene/nano-Au composites. The process was that graphene oxide and HAuCl 4 was electrochemically co-reduced onto the glassy carbon electrode (GCE) by cyclic voltammetry in one step. The obtained graphene/nano-Au/GCE exhibited high electrocatalytic activity toward H 2 O 2 , which resulted in a remarkable decrease in the overpotential of H 2 O 2 electrochemical oxidation compared with bare GCE. Such electrocatalytic behavior of the graphene/nano-Au/GCE permitted effective low-potential amperometric biosensing of glucose via the incorporation of glucose oxidase (GOD) with graphene/nano-Au. An obvious advantage of this enzyme electrode (graphene/nano-Au/GOD/GCE) was that the graphene/nano-Au nanocomposites provided a favorable microenvironment for GOD and facilitated the electron transfer between the active center of GOD and electrode. The immobilized GOD showed a direct, reversible redox reaction. Furthermore, the graphene/nano-Au/GOD/GCE was used as a glucose biosensor, displaying a low detection limit of 17 μM (S/N = 3), a high sensitivity of 56.93 μA mM −1 cm −2 , acceptable reproducibility, very good stability, selectivity and anti-interference ability

  7. Target-responsive aptamer release from manganese dioxide nanosheets for electrochemical sensing of cocaine with target recycling amplification.

    Science.gov (United States)

    Chen, Zongbao; Lu, Minghua

    2016-11-01

    A novel electrochemical sensing platform based on manganese dioxide (MnO2) nanosheets was developed for sensitive screening of target cocaine with the signal amplification. Ferrocene-labeled cocaine aptamers were initially immobilized onto MnO2 nanosheets-modified screen-printed carbon electrode because of π-stacking interaction between nucleobases and nanosheets. The immobilized ferrocene-aptamer activated the electrical contact with the electrode, thereby resulting in the sensor circuit to switch on. Upon target cocaine introduction, the analyte reacted with the aptamer and caused the dissociation of ferrocene-aptamer from the electrode, thus giving rise to the detection circuit to switch off. The released aptamer was cleaved by DNase I with target recycling. Under optimal conditions, the decreasing percentage of the electronic signal relative to background current increased with the increasing cocaine concentration in the dynamic range of 0.1-20nM, and the detection limit was 32pM. The reproducibility, selectivity and method accuracy were acceptable. Importantly, this concept offers promise for rapid, simple, and cost-effective analysis of cocaine biological samples without the needs of sample separation and multiple washing steps. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Electrochemical detection of ultratrace nitroaromatic explosives using ordered mesoporous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Zang Jianfeng; Guo Chunxian; Hu Fengping [School of Chemical and Biomedical Engineering and Center for Advanced Bionanosystems, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457 (Singapore); Yu Lei [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, Storrs, CT 06269 (United States); Li Changming, E-mail: ecmli@ntu.edu.sg [School of Chemical and Biomedical Engineering and Center for Advanced Bionanosystems, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457 (Singapore)

    2011-01-10

    A sensitive electrochemical sensor has been fabricated to detect ultratrace nitroaromatic explosives using ordered mesoporus carbon (OMC). OMC was synthesized and characterized by scanning electron microscopy, transmission electron microscopy and nitrogen adsorption/desorption measurements. Glassy carbon electrodes functionalized with OMC show high sensitivity of 62.7 {mu}A cm{sup -2} per ppb towards 2,4,6-trinitrotoluene (TNT). By comparison with other materials such as carbon nanotubes and ordered mesoporous silica, it is found that the high performance of OMC toward sensing TNT is attributed to its large specific surface area and fast electron transfer capability. As low as 0.2 ppb TNT, 1 ppb 2,4-dinitrotoluene and 1 ppb 1,3-dinitrobenzene can be detected on OMC based electrodes. This work renders new opportunities to detect ultratrace explosives for applications of environment protections and home securities against chemical warfare agents.

  9. Bismuth chalcogenide compounds Bi 2 × 3 (X=O, S, Se): Applications in electrochemical energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Jiangfeng; Bi, Xuanxuan; Jiang, Yu; Li, Liang; Lu, Jun

    2017-04-01

    Bismuth chalcogenides Bi2×3 (X=O, S, Se) represent a unique type of materials in diverse polymorphs and configurations. Multiple intrinsic features of Bi2×3 such as narrow bandgap, ion conductivity, and environmental friendliness, have render them attractive materials for a wide array of energy applications. In particular, their rich structural voids and the alloying capability of Bi enable the chalcogenides to be alternative electrodes for energy storage such as hydrogen (H), lithium (Li), sodium (Na) storage and supercapacitors. However, the low conductivity and poor electrochemical cycling are two key challenges for the practical utilization of Bi2×3 electrodes. Great efforts have been devoted to mitigate these challenges and remarkable progresses have been achieved, mainly taking profit of nanotechnology and material compositing engineering. In this short review, we summarize state-of-the-art research advances in the rational design of diverse Bi2×3 electrodes and their electrochemical energy storage performance for H, Li, and Na and supercapacitors. We also highlight the key technical issues at present and provide insights for the future development of bismuth based materials in electrochemical energy storage devices.

  10. Real-time monitoring of quorum sensing in 3D-printed bacterial aggregates using scanning electrochemical microscopy.

    Science.gov (United States)

    Connell, Jodi L; Kim, Jiyeon; Shear, Jason B; Bard, Allen J; Whiteley, Marvin

    2014-12-23

    Microbes frequently live in nature as small, densely packed aggregates containing ∼10(1)-10(5) cells. These aggregates not only display distinct phenotypes, including resistance to antibiotics, but also, serve as building blocks for larger biofilm communities. Aggregates within these larger communities display nonrandom spatial organization, and recent evidence indicates that this spatial organization is critical for fitness. Studying single aggregates as well as spatially organized aggregates remains challenging because of the technical difficulties associated with manipulating small populations. Micro-3D printing is a lithographic technique capable of creating aggregates in situ by printing protein-based walls around individual cells or small populations. This 3D-printing strategy can organize bacteria in complex arrangements to investigate how spatial and environmental parameters influence social behaviors. Here, we combined micro-3D printing and scanning electrochemical microscopy (SECM) to probe quorum sensing (QS)-mediated communication in the bacterium Pseudomonas aeruginosa. Our results reveal that QS-dependent behaviors are observed within aggregates as small as 500 cells; however, aggregates larger than 2,000 bacteria are required to stimulate QS in neighboring aggregates positioned 8 μm away. These studies provide a powerful system to analyze the impact of spatial organization and aggregate size on microbial behaviors.

  11. Tin Oxide Nanorod Array-Based Electrochemical Hydrogen Peroxide Biosensor

    Directory of Open Access Journals (Sweden)

    Liu Jinping

    2010-01-01

    Full Text Available Abstract SnO2 nanorod array grown directly on alloy substrate has been employed as the working electrode of H2O2 biosensor. Single-crystalline SnO2 nanorods provide not only low isoelectric point and enough void spaces for facile horseradish peroxidase (HRP immobilization but also numerous conductive channels for electron transport to and from current collector; thus, leading to direct electrochemistry of HRP. The nanorod array-based biosensor demonstrates high H2O2 sensing performance in terms of excellent sensitivity (379 μA mM−1 cm−2, low detection limit (0.2 μM and high selectivity with the apparent Michaelis–Menten constant estimated to be as small as 33.9 μM. Our work further demonstrates the advantages of ordered array architecture in electrochemical device application and sheds light on the construction of other high-performance enzymatic biosensors.

  12. Metal-core@metal oxide-shell nanomaterials for gas-sensing applications: a review

    Energy Technology Data Exchange (ETDEWEB)

    Mirzaei, A.; Janghorban, K.; Hashemi, B. [Shiraz University, Department of Materials Science and Engineering (Iran, Islamic Republic of); Neri, G., E-mail: gneri@unime.it [University of Messina, Department of Electronic Engineering, Chemistry and Industrial Engineering (Italy)

    2015-09-15

    With an ever-increasing number of applications in many advanced fields, gas sensors are becoming indispensable devices in our daily life. Among different types of gas sensors, conductometric metal oxide semiconductor (MOS) gas sensors are found to be the most appealing for advanced applications in the automotive, biomedical, environmental, and safety sectors because of the their high sensitivity, reduced size, and low cost. To improve their sensing characteristics, new metal oxide-based nanostructures have thus been proposed in recent years as sensing materials. In this review, we extensively review gas-sensing properties of core@ shell nanocomposites in which metals as the core and metal oxides as the shell structure, both of nanometer sizes, are assembled into a single metal@metal oxide core–shell. These nanostructures not only combine the properties of both noble metals and metal oxides, but also bring unique synergetic functions in comparison with single-component materials. Up-dated achievements in the synthesis and characterization of metal@metal oxide core–shell nanostructures as well as their use in MOS sensors are here reported with the main objective of providing an overview about their gas-sensing properties.

  13. The Application of KINECT Motion Sensing Technology in Game-Oriented Study

    Directory of Open Access Journals (Sweden)

    Hui Yu Yang

    2014-03-01

    Full Text Available The learning environment based on the KINECT Motion Sensing technology is able to fully mobilize the learners' multi-sensory organs, closely combine study with sports and enhance human-computer interactions, which can be conducive to the learners' health, greatly increase the relishes of learning and promote effective learning in the game, and finally compensate for the shortage of human-computer interactions in the traditional mouse and keyboard mode. The article elaborates on the KINECT Motion Sensing Technology and its educational applications status by analyzing its effective supports for game-oriented studying environment, based on which the article establishes a game-oriented learning environment. Eventually the article reveals an applicable case of game-oriented teaching and learning as a reference for related researches.

  14. Palladium nanoparticles in electrochemical sensing of trace terazosin in human serum and pharmaceutical preparations

    Energy Technology Data Exchange (ETDEWEB)

    Sefid-sefidehkhan, Yasaman [Department of Chemistry, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of); Nekoueian, Khadijeh [Laboratory of Green Chemistry, Faculty of Technology, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Amiri, Mandana, E-mail: mandanaamiri@uma.ac.ir [Department of Chemistry, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of); Sillanpaa, Mika [Laboratory of Green Chemistry, Faculty of Technology, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Eskandari, Habibollah [Department of Chemistry, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of)

    2017-06-01

    In this approach, palladium nanoparticle film was simply fabricated on the surface of carbon paste electrode by electrochemical deposition method. The film was characterized using scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The prepared electrode exhibited an excellent electrocatalytic activity toward detection of trace amounts of terazosin, which is an antihypertensive drug. Under the optimum experimental conditions, a linear range of 1.0 × 10{sup −8}–1.0 × 10{sup −3} mol L{sup −1} with a detection limit of 1.9 × 10{sup −9} mol L{sup −1} was obtained for determination of terazosin using differential pulse voltammetry as a sensitive method. The efficiency of palladium nanoparticle film on the surface of carbon paste electrode successfully proved for determination of terazosin in pharmaceutical sample and human serum sample with promising recovery results. The effect of some foreign species has been studied. - Highlights: • PdNPs were simply fabricated by electrochemical deposition. • PdNPs exhibited an excellent electrocatalytic activity toward oxidation of terazosin. • Terazosin has been determined in pharmaceutical sample and human serum sample.

  15. Manganese oxide-based materials as electrochemical supercapacitor electrodes.

    Science.gov (United States)

    Wei, Weifeng; Cui, Xinwei; Chen, Weixing; Ivey, Douglas G

    2011-03-01

    Electrochemical supercapacitors (ECs), characteristic of high power and reasonably high energy densities, have become a versatile solution to various emerging energy applications. This critical review describes some materials science aspects on manganese oxide-based materials for these applications, primarily including the strategic design and fabrication of these electrode materials. Nanostructurization, chemical modification and incorporation with high surface area, conductive nanoarchitectures are the three major strategies in the development of high-performance manganese oxide-based electrodes for EC applications. Numerous works reviewed herein have shown enhanced electrochemical performance in the manganese oxide-based electrode materials. However, many fundamental questions remain unanswered, particularly with respect to characterization and understanding of electron transfer and atomic transport of the electrochemical interface processes within the manganese oxide-based electrodes. In order to fully exploit the potential of manganese oxide-based electrode materials, an unambiguous appreciation of these basic questions and optimization of synthesis parameters and material properties are critical for the further development of EC devices (233 references).

  16. Palladium nanoparticles decorated on activated fullerene modified screen printed carbon electrode for enhanced electrochemical sensing of dopamine.

    Science.gov (United States)

    Palanisamy, Selvakumar; Thirumalraj, Balamurugan; Chen, Shen-Ming; Ali, M Ajmal; Al-Hemaid, Fahad M A

    2015-06-15

    In the present work, an enhanced electrochemical sensor for dopamine (DA) was developed based on palladium nanoparticles decorated activated fullerene-C60 (AC60/PdNPs) composite modified screen printed carbon electrode (SPCE). The scanning electron microscopy and elemental analysis confirmed the formation of PdNPs on AC60. The fabricated AC60/PdNPs composite modified electrode exhibited an enhanced electrochemical response to DA with a lower oxidation potential than that of SPCE modified with PdNPs and C60, indicating the excellent electrooxidation behavior of the AC60/PdNPs composite modified electrode. The electrochemical studies confirmed that the electrooxidation of DA at the composite electrode is a diffusion controlled electrochemical process. The differential pulse voltammetry was employed for the determination of DA; under optimum conditions, the electrochemical oxidation signal of DA increased linearly at the AC60/PdNPs composite from 0.35 to 133.35 μM. The limit of detection was found as 0.056 μM with a sensitivity of 4.23 μA μM(-1) cm(-2). The good recovery of DA in the DA injection samples further revealed the good practicality of AC60/PdNPs modified electrode. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Electrochemical fabrication and electronic behavior of polypyrrole nano-fiber array devices

    International Nuclear Information System (INIS)

    Liu Ling; Zhao Yaomin; Jia Nengqin; Zhou Qin; Zhao Chongjun; Yan Manming; Jiang Zhiyu

    2006-01-01

    Electrochemically active Polypyrrole (PPy) nano-fiber array device was fabricated via electrochemical deposition method using aluminum anodic oxide (AAO) membrane as template. After alkaline treatment electrochemically active PPy nano-fiber lost electrochemical activity, and became electrochemically inactive PPy. The electronic properties of PPy nano-fiber array devices were measured by means of a simple method. It was found that for an indium-tin oxide/electrochemically inactive PPy nano-fiber device, the conductivity of nano-fiber increased with the increase of voltage applied on the two terminals of nano-fiber. The electrochemical inactive PPy nano-fiber might be used as a nano-fiber switching diode. Both Au/electrochemically active PPy and Au/electrochemically inactive PPy nano-fiber devices demonstrate rectifying behavior, and might have been used for further application as nano-rectifiers

  18. Electrochemical fabrication and electronic behavior of polypyrrole nano-fiber array devices

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Liu [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Yaomin, Zhao [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Nengqin, Jia [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Qin, Zhou [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Chongjun, Zhao [Photon Craft Project, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences and Japan Science and Technology Agency, Shanghai 201800 (China); Manming, Yan [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Zhiyu, Jiang [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China)

    2006-05-01

    Electrochemically active Polypyrrole (PPy) nano-fiber array device was fabricated via electrochemical deposition method using aluminum anodic oxide (AAO) membrane as template. After alkaline treatment electrochemically active PPy nano-fiber lost electrochemical activity, and became electrochemically inactive PPy. The electronic properties of PPy nano-fiber array devices were measured by means of a simple method. It was found that for an indium-tin oxide/electrochemically inactive PPy nano-fiber device, the conductivity of nano-fiber increased with the increase of voltage applied on the two terminals of nano-fiber. The electrochemical inactive PPy nano-fiber might be used as a nano-fiber switching diode. Both Au/electrochemically active PPy and Au/electrochemically inactive PPy nano-fiber devices demonstrate rectifying behavior, and might have been used for further application as nano-rectifiers.

  19. Fabrication of bismuth ferrite based hybrid nanostructures: Insight into a catalytic and sensing properties for the detection of biomolecules

    Science.gov (United States)

    Bharathkumar, S.; Sakar, M.; Balakumar, S.

    2018-04-01

    We made an attempt to construct a photocatalytic and biosensor platform by using bismuth ferrite (BiFeO3/BFO) particulates and fibers nanostructures towards the degradation of dye and electrochemical sensing of ascorbic acid. The crystal phase and morphology of the BFO nanostructures were confirmed using XRD and FESEM respectively. Further, their photocatalytic activity was tested under sunlight. The BFO fibers showed relatively an enhanced degradation property and an efficient electrochemical sensing property compared to the Particulates.

  20. Climate Literacy: STEM and Climate Change Education and Remote Sensing Applications

    Science.gov (United States)

    Reddy, S. R.

    2015-12-01

    NASA Innovations in Climate Education (NICE) is a competitive project to promote climate and Earth system science literacy and seeks to increase the access of underrepresented minority groups to science careers and educational opportunities. A three year funding was received from NASA to partnership with JSU and MSU under cooperative agreement "Strengthening Global Climate Change education through Remote Sensing Application in Coastal Environment using NASA Satellite Data and Models". The goal is to increase the number of highschool and undergraduate students at Jackson State University, a Historically Black University, who are prepared to pursue higher academic degrees and careers in STEM fields. A five Saturday course/workshop was held during March/April 2015 at JSU, focusing on historical and technical concepts of math, enginneering, technology and atmosphere and climate change and remote sensing technology and applications to weather and climate. Nine students from meteorology, biology, industrial technology and computer science/engineering of JSU and 19 high scool students from Jackson Public Schools participated in the course/workshop. The lecture topics include: introduction to remote sensing and GIS, introduction to atmospheric science, math and engineering, climate, introduction to NASA innovations in climate education, introduction to remote sensing technology for bio-geosphere, introduction to earth system science, principles of paleoclimatology and global change, daily weather briefing, satellite image interpretation and so on. In addition to lectures, lab sessions were held for hand-on experiences for remote sensing applications to atmosphere, biosphere, earth system science and climate change using ERDAS/ENVI GIS software and satellite tools. Field trip to Barnett reservoir and National weather Service (NWS) was part of the workshop. Basics of Earth System Science is a non-mathematical introductory course designed for high school seniors, high school

  1. Electrochemical and Infrared Absorption Spectroscopy Detection of SF6 Decomposition Products

    Directory of Open Access Journals (Sweden)

    Ming Dong

    2017-11-01

    Full Text Available Sulfur hexafluoride (SF6 gas-insulated electrical equipment is widely used in high-voltage (HV and extra-high-voltage (EHV power systems. Partial discharge (PD and local heating can occur in the electrical equipment because of insulation faults, which results in SF6 decomposition and ultimately generates several types of decomposition products. These SF6 decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF6 decomposition products, and electrochemical sensing (ES and infrared (IR spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF6 gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF6 decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF6 gas decomposition and is verified to reliably and accurately detect the gas components and concentrations.

  2. Electrochemical and Infrared Absorption Spectroscopy Detection of SF6 Decomposition Products

    Science.gov (United States)

    Dong, Ming; Ren, Ming; Ye, Rixin

    2017-01-01

    Sulfur hexafluoride (SF6) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF6 decomposition and ultimately generates several types of decomposition products. These SF6 decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF6 decomposition products, and electrochemical sensing (ES) and infrared (IR) spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF6 gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF6 decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF6 gas decomposition and is verified to reliably and accurately detect the gas components and concentrations. PMID:29140268

  3. Optimization of design parameters for bulk micromachined silicon membranes for piezoresistive pressure sensing application

    International Nuclear Information System (INIS)

    Belwanshi, Vinod; Topkar, Anita

    2016-01-01

    Finite element analysis study has been carried out to optimize the design parameters for bulk micro-machined silicon membranes for piezoresistive pressure sensing applications. The design is targeted for measurement of pressure up to 200 bar for nuclear reactor applications. The mechanical behavior of bulk micro-machined silicon membranes in terms of deflection and stress generation has been simulated. Based on the simulation results, optimization of the membrane design parameters in terms of length, width and thickness has been carried out. Subsequent to optimization of membrane geometrical parameters, the dimensions and location of the high stress concentration region for implantation of piezoresistors have been obtained for sensing of pressure using piezoresistive sensing technique.

  4. Optimization of design parameters for bulk micromachined silicon membranes for piezoresistive pressure sensing application

    Science.gov (United States)

    Belwanshi, Vinod; Topkar, Anita

    2016-05-01

    Finite element analysis study has been carried out to optimize the design parameters for bulk micro-machined silicon membranes for piezoresistive pressure sensing applications. The design is targeted for measurement of pressure up to 200 bar for nuclear reactor applications. The mechanical behavior of bulk micro-machined silicon membranes in terms of deflection and stress generation has been simulated. Based on the simulation results, optimization of the membrane design parameters in terms of length, width and thickness has been carried out. Subsequent to optimization of membrane geometrical parameters, the dimensions and location of the high stress concentration region for implantation of piezoresistors have been obtained for sensing of pressure using piezoresistive sensing technique.

  5. Undoped CVD diamond films for electrochemical applications

    International Nuclear Information System (INIS)

    Mosinska, Lidia; Fabisiak, Kazimierz; Paprocki, Kazimierz; Kowalska, Magdalena; Popielarski, Pawel; Szybowicz, Miroslaw

    2013-01-01

    By using different deposition conditions, the CVD diamond films with different qualities and orientation were grown by the hot-filament CVD technique. The object of this article is to summarize and discuss relation between structural, physical and electrochemical properties of different diamond electrodes. The physical properties of the Hot Filament CVD microcrystalline diamond films are analyzed by scanning electron microscopy and Raman spectroscopy. In presented studies two different electrodes were used of the diamond grain sizes around 200 nm and 10 μm, as it was estimated from SEM picture. The diamond layers quality was checked on basis of FWHM (Full width at Half Maximum) of 1332 cm −1 diamond Raman peak. The ratio of sp 3 /sp 2 carbon bonds was determined by 1550 cm −1 G band and 1350 cm −1 D band in the Raman spectrum. The electrochemical properties were analyzed using (CV) cyclic voltammetry measurements in aqueous solutions. The sensitivity of undoped diamond electrodes depends strongly on diamond film quality and concentration of amorphous carbon phase in the diamond layer

  6. POLARIZATION REMOTE SENSING PHYSICAL MECHANISM, KEY METHODS AND APPLICATION

    Directory of Open Access Journals (Sweden)

    B. Yang

    2017-09-01

    Full Text Available China's long-term planning major projects "high-resolution earth observation system" has been invested nearly 100 billion and the satellites will reach 100 to 2020. As to 2/3 of China's area covered by mountains,it has a higher demand for remote sensing. In addition to light intensity, frequency, phase, polarization is also the main physical characteristics of remote sensing electromagnetic waves. Polarization is an important component of the reflected information from the surface and the atmospheric information, and the polarization effect of the ground object reflection is the basis of the observation of polarization remote sensing. Therefore, the effect of eliminating the polarization effect is very important for remote sensing applications. The main innovations of this paper is as follows: (1 Remote sensing observation method. It is theoretically deduced and verified that the polarization can weaken the light in the strong light region, and then provide the polarization effective information. In turn, the polarization in the low light region can strengthen the weak light, the same can be obtained polarization effective information. (2 Polarization effect of vegetation. By analyzing the structure characteristics of vegetation, polarization information is obtained, then the vegetation structure information directly affects the absorption of biochemical components of leaves. (3 Atmospheric polarization neutral point observation method. It is proved to be effective to achieve the ground-gas separation, which can achieve the effect of eliminating the atmospheric polarization effect and enhancing the polarization effect of the object.

  7. Remote sensing and implications for variable-rate application using agricultural aircraft

    Science.gov (United States)

    Thomson, Steven J.; Smith, Lowrey A.; Ray, Jeffrey D.; Zimba, Paul V.

    2004-01-01

    Aircraft routinely used for agricultural spray application are finding utility for remote sensing. Data obtained from remote sensing can be used for prescription application of pesticides, fertilizers, cotton growth regulators, and water (the latter with the assistance of hyperspectral indices and thermal imaging). Digital video was used to detect weeds in early cotton, and preliminary data were obtained to see if nitrogen status could be detected in early soybeans. Weeds were differentiable from early cotton at very low altitudes (65-m), with the aid of supervised classification algorithms in the ENVI image analysis software. The camera was flown at very low altitude for acceptable pixel resolution. Nitrogen status was not detectable by statistical analysis of digital numbers (DNs) obtained from images, but soybean cultivar differences were statistically discernable (F=26, p=0.01). Spectroradiometer data are being analyzed to identify narrow spectral bands that might aid in selecting camera filters for determination of plant nitrogen status. Multiple camera configurations are proposed to allow vegetative indices to be developed more readily. Both remotely sensed field images and ground data are to be used for decision-making in a proposed variable-rate application system for agricultural aircraft. For this system, prescriptions generated from digital imagery and data will be coupled with GPS-based swath guidance and programmable flow control.

  8. Nanostructured Inorganic Materials at Work in Electrochemical Sensing and Biofuel Cells

    Directory of Open Access Journals (Sweden)

    Yaovi Holade

    2017-01-01

    Full Text Available The future of analytical devices, namely (biosensors, which are currently impacting our everyday life, relies on several metrics such as low cost, high sensitivity, good selectivity, rapid response, real-time monitoring, high-throughput, easy-to-make and easy-to-handle properties. Fortunately, they can be readily fulfilled by electrochemical methods. For decades, electrochemical sensors and biofuel cells operating in physiological conditions have concerned biomolecular science where enzymes act as biocatalysts. However, immobilizing them on a conducting substrate is tedious and the resulting bioelectrodes suffer from stability. In this contribution, we provide a comprehensive, authoritative, critical, and readable review of general interest that surveys interdisciplinary research involving materials science and (bioelectrocatalysis. Specifically, it recounts recent developments focused on the introduction of nanostructured metallic and carbon-based materials as robust “abiotic catalysts” or scaffolds in bioelectrochemistry to boost and increase the current and readout signals as well as the lifetime. Compared to biocatalysts, abiotic catalysts are in a better position to efficiently cope with fluctuations of temperature and pH since they possess high intrinsic thermal stability, exceptional chemical resistance and long-term stability, already highlighted in classical electrocatalysis. We also diagnosed their intrinsic bottlenecks and highlighted opportunities of unifying the materials science and bioelectrochemistry fields to design hybrid platforms with improved performance.

  9. Biomedical Probes Based on Inorganic Nanoparticles for Electrochemical and Optical Spectroscopy Applications

    Science.gov (United States)

    Yakoh, Abdulhadee; Pinyorospathum, Chanika; Siangproh, Weena; Chailapakul, Orawon

    2015-01-01

    Inorganic nanoparticles usually provide novel and unique physical properties as their size approaches nanometer scale dimensions. The unique physical and optical properties of nanoparticles may lead to applications in a variety of areas, including biomedical detection. Therefore, current research is now increasingly focused on the use of the high surface-to-volume ratios of nanoparticles to fabricate superb chemical- or biosensors for various detection applications. This article highlights various kinds of inorganic nanoparticles, including metal nanoparticles, magnetic nanoparticles, nanocomposites, and semiconductor nanoparticles that can be perceived as useful materials for biomedical probes and points to the outstanding results arising from their use in such probes. The progress in the use of inorganic nanoparticle-based electrochemical, colorimetric and spectrophotometric detection in recent applications, especially bioanalysis, and the main functions of inorganic nanoparticles in detection are reviewed. The article begins with a conceptual discussion of nanoparticles according to types, followed by numerous applications to analytes including biomolecules, disease markers, and pharmaceutical substances. Most of the references cited herein, dating from 2010 to 2015, generally mention one or more of the following characteristics: a low detection limit, good signal amplification and simultaneous detection capabilities. PMID:26343676

  10. A MEMS Electrochemical Bellows Actuator for Fluid Metering Applications

    Science.gov (United States)

    Sheybani, Roya; Gensler, Heidi; Meng, Ellis

    2013-01-01

    We present a high efficiency wireless MEMS electrochemical bellows actuator capable of rapid and repeatable delivery of boluses for fluid metering and drug delivery applications. Nafion®-coated Pt electrodes were combined with Parylene bellows filled with DI water to form the electrolysis-based actuator. The performance of actuators with several bellows configurations was compared for a range of applied currents (1-10 mA). Up to 75 boluses were delivered with an average pumping flow rate of 114.40 ± 1.63 μL/min. Recombination of gases into water, an important factor in repeatable and reliable actuation, was studied for uncoated and Nafion®-coated actuators. Real-time pressure measurements were conducted and the effects of temperature, physiological back pressure, and drug viscosity on delivery performance were investigated. Lastly, we present wireless powering of the actuator using a class D inductive powering system that allowed for repeatable delivery with less than 2% variation in flow rate values. PMID:22833156

  11. Preparation and electrochemical application of a new biosensor ...

    Indian Academy of Sciences (India)

    The electrocatalytic behaviour of oxidized acetaminophen was studied at the surface of the biosensor, using various electrochemical methods. The advantages of this ..... each case, a few ml of methanol was added to sample, and then it was ...

  12. Privacy Protection in Participatory Sensing Applications Requiring Fine-Grained Locations

    DEFF Research Database (Denmark)

    Dong, Kai; Gu, Tao; Tao, Xianping

    2010-01-01

    The emerging participatory sensing applications have brought a privacy risk where users expose their location information. Most of the existing solutions preserve location privacy by generalizing a precise user location to a coarse-grained location, and hence they cannot be applied in those appli...... provider is an trustworthy entity, making our solution more feasible to practical applications. We present and analyze our security model, and evaluate the performance and scalability of our system....

  13. Novel membrane-based electrochemical sensor for real-time bio-applications

    DEFF Research Database (Denmark)

    Al Atraktchi, Fatima Al-Zahraa; Bakmand, Tanya; Dimaki, Maria

    2014-01-01

    This article presents a novel membrane-based sensor for real-time electrochemical investigations of cellular- or tissue cultures. The membrane sensor enables recording of electrical signals from a cell culture without any signal dilution, thus avoiding loss of sensitivity. Moreover, the porosity...... of the membrane provides optimal culturing conditions similar to existing culturing techniques allowing more efficient nutrient uptake and molecule release. The patterned sensor electrodes were fabricated on a porous membrane by electron-beam evaporation. The electrochemical performance of the membrane electrodes...

  14. Proceedings of the Eleventh International Symposium on Remote Sensing of Environment, volume 2. [application and processing of remotely sensed data

    Science.gov (United States)

    1977-01-01

    Application and processing of remotely sensed data are discussed. Areas of application include: pollution monitoring, water quality, land use, marine resources, ocean surface properties, and agriculture. Image processing and scene analysis are described along with automated photointerpretation and classification techniques. Data from infrared and multispectral band scanners onboard LANDSAT satellites are emphasized.

  15. Recurrent potential pulse technique for improvement of glucose sensing ability of 3D polypyrrole

    Science.gov (United States)

    Cysewska, Karolina; Karczewski, Jakub; Jasiński, Piotr

    2017-07-01

    In this work, a new approach for using a 3D polypyrrole (PPy) conducting polymer as a sensing material for glucose detection is proposed. Polypyrrole is electrochemically polymerized on a platinum screen-printed electrode in an aqueous solution of lithium perchlorate and pyrrole. PPy exhibits a high electroactive surface area and high electrochemical stability, which results in it having excellent electrocatalytic properties. The studies show that using the recurrent potential pulse technique results in an increase in PPy sensing stability, compared to the amperometric approach. This is due to the fact that the technique, under certain parameters, allows the PPy redox properties to be fully utilized, whilst preventing its anodic degradation. Because of this, the 3D PPy presented here has become a very good candidate as a sensing material for glucose detection, and can work without any additional dopants, mediators or enzymes.

  16. Preparation and application of a novel electrochemical sensing material based on surface chemistry of polyhydroquinone

    International Nuclear Information System (INIS)

    Dang, Xueping; Wang, Yingkai; Hu, Chengguo; Huang, Jianlin; Chen, Huaixia; Wang, Shengfu; Hu, Shengshui

    2014-01-01

    A new analogue of polydopamine (PDA), i.e., polyhydroquinone (PH 2 Q), was polymerized and its surface chemistry was studied by different ways of characterization. PH 2 Q was produced by the self-polymerization of H 2 Q mediated by dissolved oxygen, and the self-polymerization process was strongly dependent on the type and the pH value of the buffer solutions. PH 2 Q can not only achieve surface hydrophilization of different substrates like polyethylene terephthalate (PET) film, graphite strip, C 12 SH/Au and wax slice, but also possess several unique properties like reversible adsorption, good solubility and low cost. These properties made PH 2 Q an ideal polymeric modifier for the noncovalent functionalization of some nanomaterials. By simply grinding with PH 2 Q, pristine multi-walled carbon nanotubes (MWNTs) can be readily dispersed in water with high solubility and good stability. The resulting MWNT–PH 2 Q composite exhibited excellent electrochemical performance, which was employed for the simultaneous determination of dopamine (DA) and uric acid (UA). - Highlights: • Polyhydroquinone (PH 2 Q) was produced by the self-polymerization of hydroquinone (H 2 Q) mediated by dissolved oxygen. • PH 2 Q can achieve surface hydrophilization of a variety of substrates. • PH 2 Q is an ideal polymeric modifier for the functionalization of multi-walled carbon nanotubes (MWNTs). • The MWNT–PH 2 Q composite can be employed for the simultaneous determination of dopamine (DA) and uric acid (UA)

  17. The electrochemical signature of functionalized single-walled carbon nanotubes bearing electroactive groups

    International Nuclear Information System (INIS)

    Le Floch, Fabien; Thuaire, Aurelie; Simonato, Jean-Pierre; Bidan, Gerard

    2009-01-01

    We report the modification and characterization of single-walled carbon nanotubes (SWCNTs) in view of molecular sensing applications. We found that ultrasonicated SWCNTs present sticking properties that make them adhere on electrode surfaces. This allows excellent characterization of SWCNTs by cyclic voltammetry (CV) before and after chemical functionalization with diazonium salts bearing electroactive groups. Bare SWCNTs presented distinct invariant shapes in CV, used as control curves, in comparison with functionalized SWCNTs for which specific signatures corresponding to the presence of grafted molecules were identified. According to the electronic substituents in the para position of the diazonium salts, divergent behaviours were observed for the grafting reactions. Diazonium salts having electrowithdrawing groups could be grafted without electrochemical induction whereas those bearing electron donating groups required a cathodic potential to generate the formation of the radical species.

  18. The electrochemical signature of functionalized single-walled carbon nanotubes bearing electroactive groups

    Energy Technology Data Exchange (ETDEWEB)

    Le Floch, Fabien; Thuaire, Aurelie; Simonato, Jean-Pierre [LITEN/DTNM/LCRE, CEA-Grenoble 17 rue des Martyrs, 38054 Grenoble cedex 9 (France); Bidan, Gerard [INAC/DIR, CEA-Grenoble 17 rue des Martyrs, 38054 Grenoble cedex 9 (France)], E-mail: jean-pierre.simonato@cea.fr

    2009-04-08

    We report the modification and characterization of single-walled carbon nanotubes (SWCNTs) in view of molecular sensing applications. We found that ultrasonicated SWCNTs present sticking properties that make them adhere on electrode surfaces. This allows excellent characterization of SWCNTs by cyclic voltammetry (CV) before and after chemical functionalization with diazonium salts bearing electroactive groups. Bare SWCNTs presented distinct invariant shapes in CV, used as control curves, in comparison with functionalized SWCNTs for which specific signatures corresponding to the presence of grafted molecules were identified. According to the electronic substituents in the para position of the diazonium salts, divergent behaviours were observed for the grafting reactions. Diazonium salts having electrowithdrawing groups could be grafted without electrochemical induction whereas those bearing electron donating groups required a cathodic potential to generate the formation of the radical species.

  19. Sensing at the nanoscale

    Science.gov (United States)

    Demming, Anna; Hierold, Christofer

    2013-11-01

    label-free detection of DNA at concentrations as low as 1-10 fM, a sensitivity comparable to the best signal amplification-assisted electrochemical sensors reported [12]. In another study actin-conjugated gold and silver nanorods are used to detect ATP, a common indicator of cell viability [13]. They show how aggregation induced by ATP-induced polymerization of the G-actin gives rise to a measurable change in the plasmon resonance absorbance of the nanorods. A review of the use of fluorescent silica nanoparticles for biomedical applications is provided by researchers at Dublin City University in Ireland [14]. The first scanning tunnelling microscope in the early 1980s and subsequent scanning probe developments brought the world of nanoscale structures into view in a manner that gorged the imaginations of scientists and the public. New ways of probing structures at this scale revealed a wealth of curious properties that triggered a surge of research activity in nanotechnology, now a multibillion dollar industry. One good turn deserves another and in fact nanostructures provide the perfect tools for the type of sensing and imaging applications that brought such widespread research interest to nanotechnology. This special issue highlights just how broad and innovative the range of sensing nanotechnologies has grown. References [1] Zappa D, Comini E and Sberveglieri G 2013 Thermally-oxidized zinc oxide nanowires chemical sensors Nanotechnology 24 444008 [2] Kemmler J A, Pokhrel S, Mädler L, Weimar U and Barsan N 2013 Flame spray pyrolysis for sensing at the nanoscale Nanotechnology 24 442001 [3] Bache M et al 2013 Nanomechanical recognition of prognostic biomarker suPAR with DVD-ROM optical technology Nanotechnology 24 444011 [4] Hu C-F, Wang J-Y, Liu Y-C, Tsai M-H and Fang W 2013 Development of 3D carbon nanotubes interdigitated finger electrodes on polymer substrate for flexible capacitive sensor application Nanotechnology 24 444006 [5] Neumann C, Volk C, Engels S and

  20. Evaluation and improvement of dynamic optimality in electrochemical reactors

    International Nuclear Information System (INIS)

    Vijayasekaran, B.; Basha, C. Ahmed

    2005-01-01

    A systematic approach for the dynamic optimization problem statement to improve the dynamic optimality in electrochemical reactors is presented in this paper. The formulation takes an account of the diffusion phenomenon in the electrode/electrolyte interface. To demonstrate the present methodology, the optimal time-varying electrode potential for a coupled chemical-electrochemical reaction scheme, that maximizes the production of the desired product in a batch electrochemical reactor with/without recirculation are determined. The dynamic optimization problem statement, based upon this approach, is a nonlinear differential algebraic system, and its solution provides information about the optimal policy. Optimal control policy at different conditions is evaluated using the best-known Pontryagin's maximum principle. The two-point boundary value problem resulting from the application of the maximum principle is then solved using the control vector iteration technique. These optimal time-varying profiles of electrode potential are then compared to the best uniform operation through the relative improvements of the performance index. The application of the proposed approach to two electrochemical systems, described by ordinary differential equations, shows that the existing electrochemical process control strategy could be improved considerably when the proposed method is incorporated

  1. Compressed-sensing application - Pre-stack kirchhoff migration

    KAUST Repository

    Aldawood, Ali; Hoteit, Ibrahim; Alkhalifah, Tariq Ali

    2013-01-01

    Least-squares migration is a linearized form of waveform inversion that aims to enhance the spatial resolution of the subsurface reflectivity distribution and reduce the migration artifacts due to limited recording aperture, coarse sampling of sources and receivers, and low subsurface illumination. Least-squares migration, however, due to the nature of its minimization process, tends to produce smoothed and dispersed versions of the reflectivity of the subsurface. Assuming that the subsurface reflectivity distribution is sparse, we propose the addition of a non-quadratic L1-norm penalty term on the model space in the objective function. This aims to preserve the sparse nature of the subsurface reflectivity series and enhance resolution. We further use a compressed-sensing algorithm to solve the linear system, which utilizes the sparsity assumption to produce highly resolved migrated images. Thus, the Kirchhoff migration implementation is formulated as a Basis Pursuit denoise (BPDN) problem to obtain the sparse reflectivity model. Applications on synthetic data show that reflectivity models obtained using this compressed-sensing algorithm are highly accurate with optimal resolution.

  2. Gold/diamond nanohybrids for quantum sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Pei-Chang; Chen, Oliver Y.; Tzeng, Yan-Kai; Hui, Yuen Yung; Chang, Ming-Shien [Academia Sinica, Institute of Atomic and Molecular Sciences, Taipei (China); Guo, Jiun You; Wu, Chih-Che [National Chi Nan University, Department of Applied Chemistry, Puli, Nantou (China); Chang, Huan-Cheng [Academia Sinica, Institute of Atomic and Molecular Sciences, Taipei (China); National Taiwan University of Science and Technology, Department of Chemical Engineering, Taipei (China)

    2015-12-15

    Recent advances in quantum technology have demonstrated the potential use of negatively charged nitrogen-vacancy (NV{sup -}) centers in diamond for temperature and magnetic sensing at sub-cellular levels. Fluorescent nanodiamonds (FNDs) containing high-density ensembles of NV{sup -} centers are appealing for such applications because they are inherently biocompatible and non-toxic. Here, we show that FNDs conjugated with gold nanorods (GNRs) are useful as a combined nanoheater and nanothermometer for highly localized hyperthermia treatment using near-infrared (NIR) lasers as the heating source. A temperature rise of ∝10 K can be readily achieved at a NIR laser power of 0.4 mW in cells. The technique is compatible with the presence of static magnetic fields and allows for simultaneous temperature and magnetic sensing with nanometric spatial resolution. To elucidate the nanoscale heating process, numerical simulations are conducted with finite element analysis, providing an important guideline for the use of this new tool for active and high-precision control of temperature under diverse environmental conditions. (orig.)

  3. Interpenetrating polyaniline-gold electrodes for SERS and electrochemical measurements

    Science.gov (United States)

    West, R. M.; Semancik, S.

    2016-11-01

    Facile fabrication of nanostructured electrode arrays is critical for development of bimodal SERS and electrochemical biosensors. In this paper, the variation of applied potential at a polyaniline-coated Pt electrode is used to selectivity deposit Au on the polyaniline amine sites or on the underlying Pt electrode. By alternating the applied potential, the Au is grown simultaneously from the top and the bottom of the polyaniline film, leading to an interpenetrated, nanostructured polymer-metal composite extending from the Pt electrode to the electrolyte solution. The resulting films have unique pH-dependent electrochemical properties, e.g. they retain electrochemical activity in both acidic and neutral solutions, and they also include SERS-active nanostructures. By varying the concentration of chloroaurate used during deposition, Au nanoparticles, nanodendrites, or nanosheets can be selectively grown. For the films deposited under optimal conditions, using 5 mmol/L chloroaurate, the SERS enhancement factor for Rhodamine 6G was found to be as high as 1.1 × 106 with spot-to-spot and electrode-to-electrode relative standard deviations as low as 8% and 12%, respectively. The advantages of the reported PANI-Au composite electrodes lie in their facile fabrication, enabling the targeted deposition of tunable nanostructures on sensing arrays, and their ability to produce orthogonal optical and electrochemical analytical results.

  4. Electron transport determines the electrochemical properties of tetrahedral amorphous carbon (ta-C) thin films

    International Nuclear Information System (INIS)

    Palomäki, Tommi; Wester, Niklas; Caro, Miguel A.; Sainio, Sami; Protopopova, Vera; Koskinen, Jari; Laurila, Tomi

    2017-01-01

    Amorphous carbon based electrodes are very promising for electrochemical sensing applications. In order to better understand their structure-function relationship, the effect of film thickness on the electrochemical properties of tetrahedral amorphous carbon (ta-C) electrodes was investigated. ta-C thin films of 7, 15, 30, 50 and 100 nm were characterized in detail with Raman spectroscopy, transmission electron microscopy (TEM), conductive atomic force microscopy (c-AFM), scanning tunneling spectroscopy (STS) and X-ray absorption spectroscopy (XAS) to assess (i) the surface properties of the films, (ii) the effect of film thickness on their structure and electrical properties and (iii) the subsequent correlation with their electrochemistry. The electrochemical properties were investigated by cyclic voltammetry (CV) using two different outer-sphere redox probes, Ru(NH 3 ) 6 3+/2+ and FcMeOH, and by electrochemical impedance spectroscopy (EIS). Computational simulations using density functional theory (DFT) were carried out to rationalize the experimental findings. The characterization results showed that the sp 2 /sp 3 ratio increased with decreasing ta-C film thickness. This correlated with a decrease in mobility gap value and an increase in the average current through the films, which was also consistent with the computational results. XAS indicated that the surface of the ta-C films was always identical and composed of a sp 2 -rich layer. The CV measurements indicated reversible reaction kinetics for both outer-sphere redox probes at 7 and 15 nm ta-C films with a change to quasi-reversible behavior at a thickness of around 30 nm. The charge transfer resistance, obtained from EIS measurements, decreased with decreasing film thickness in accordance with the CV results. Based on the characterization and electrochemical results, we conclude that the reaction kinetics in the case of outer-sphere redox systems is determined mainly by the electron transport through the

  5. Synthesis and Microstructural Characterization of Manganese Oxide Electrodes for Application as Electrochemical Supercapacitors

    Science.gov (United States)

    Babakhani, Banafsheh

    The aim of this thesis work was to synthesize Mn-based oxide electrodes with high surface area structures by anodic electrodeposition for application as electrochemical capacitors. Rod-like structures provide large surface areas leading to high specific capacitances. Since templated electrosynthesis of rods is not easy to use in practical applications, it is more desirable to form rod-like structures without using any templates. In this work, Mn oxide electrodes with rod-like structures (˜1.5 µm in diameter) were synthesized from a solution of 0.01 M Mn acetate under galvanostatic control without any templates, on Au coated Si substrates. The electrochemical properties of the synthesized nanocrystalline electrodes were investigated to determine the effect of morphology, chemistry and crystal structure on the corresponding electrochemical behavior of Mn oxide electrodes. Mn oxides prepared at different current densities showed a defective antifluoritetype crystal structure. The rod-like Mn oxide electrodes synthesized at low current densities (5 mAcm.2) exhibited a high specific capacitance due to their large surface areas. Also, specific capacity retention after 250 cycles in an aqueous solution of 0.5 M Na2SO4 at 100 mVs -1 was about 78% of the initial capacity (203 Fg-1 ). To improve the electrochemical capacitive behavior of Mn oxide electrodes, a sequential approach and a one-step method were adopted to synthesize Mn oxide/PEDOT electrodes through anodic deposition on Au coated Si substrates from aqueous solutions. In the former case, free standing Mn oxide rods (about 10 µm long and less than 1.5 µm in diameter) were first synthesized, then coated by electro-polymerization of a conducting polymer (PEDOT) giving coaxial rods. The one-step, co-electrodeposition method produced agglomerated Mn oxide/PEDOT particles. The electrochemical behavior of the deposits depended on the morphology and crystal structure of the fabricated electrodes, which were affected

  6. Thermal Infrared Remote Sensing for Analysis of Landscape Ecological Processes: Methods and Applications

    Science.gov (United States)

    Quattrochi, Dale A.; Luvall, Jeffrey C.

    1998-01-01

    Thermal Infrared (TIR) remote sensing data can provide important measurements of surface energy fluxes and temperatures, which are integral to understanding landscape processes and responses. One example of this is the successful application of TIR remote sensing data to estimate evapotranspiration and soil moisture, where results from a number of studies suggest that satellite-based measurements from TIR remote sensing data can lead to more accurate regional-scale estimates of daily evapotranspiration. With further refinement in analytical techniques and models, the use of TIR data from airborne and satellite sensors could be very useful for parameterizing surface moisture conditions and developing better simulations of landscape energy exchange over a variety of conditions and space and time scales. Thus, TIR remote sensing data can significantly contribute to the observation, measurement, and analysis of energy balance characteristics (i.e., the fluxes and redistribution of thermal energy within and across the land surface) as an implicit and important aspect of landscape dynamics and landscape functioning. The application of TIR remote sensing data in landscape ecological studies has been limited, however, for several fundamental reasons that relate primarily to the perceived difficulty in use and availability of these data by the landscape ecology community, and from the fragmentation of references on TIR remote sensing throughout the scientific literature. It is our purpose here to provide evidence from work that has employed TIR remote sensing for analysis of landscape characteristics to illustrate how these data can provide important data for the improved measurement of landscape energy response and energy flux relationships. We examine the direct or indirect use of TIR remote sensing data to analyze landscape biophysical characteristics, thereby offering some insight on how these data can be used more robustly to further the understanding and modeling of

  7. Forensic electrochemistry: the electroanalytical sensing of synthetic cathinone-derivatives and their accompanying adulterants in "legal high" products.

    Science.gov (United States)

    Smith, Jamie P; Metters, Jonathan P; Irving, Craig; Sutcliffe, Oliver B; Banks, Craig E

    2014-01-21

    The production and abuse of new psychoactive substances, known as "legal highs" which mimic traditional drugs of abuse is becoming a global epidemic. Traditional analytical methodologies exist which can provide confirmatory analysis but there is a requirement for an on-the-spot analytical screening tool that could be used to determine whether a substance, or sample matrix contains such legal, or formally "legal highs". In this paper the electrochemical sensing of (±)-methcathinone and related compounds at a range of commercially available electrode substrates is explored. We demonstrate for the first time that this class of "legal highs" are electrochemically active providing a novel sensing protocol based upon their electrochemical oxidation. Screen-printed graphite sensing platforms are favoured due to their proven ability to be mass-produced providing large numbers of reliable and reproducible electrode sensing platforms that preclude the requirement of surface pre-treatment such as mechanical polishing as is the case in the use of solid/re-usable electrode substrates. Additionally they hold potential to be used on-site potentially being the basis of an on-site legal high screening device. Consequently the electroanalytical sensing of (±)-methcathinone (3a), (±)-4′-methylmethcathinone [3b, 4-MMC, (±)-mephedrone] and (±)-4′-methyl-N-ethylcathinone (3c, 4-MEC) is explored using screen-printed sensing platforms with the effect of pH explored upon the analytical response with their analytical efficiency evaluated towards the target legal highs. Interesting at pH values below 6 the voltammetric response quantitatively changes from that of an electrochemically irreversible response to that of a quasi-reversible signature which can be used analytically. It is demonstrated for the first time that the electroanalytical sensing of (±)-methcathinone (3a), (±)-mephedrone (3b) and 4-MEC (3c) are possible with accessible linear ranges found to correspond to 16

  8. Noble metal nanoparticle-functionalized ZnO nanoflowers for photocatalytic degradation of RhB dye and electrochemical sensing of hydrogen peroxide

    International Nuclear Information System (INIS)

    Hussain, Muhammad; Sun, Hongyu; Karim, Shafqat; Nisar, Amjad; Khan, Maaz; Ul Haq, Anwar; Iqbal, Munawar; Ahmad, Mashkoor

    2016-01-01

    Flower-like hierarchical Zinc oxide nanostructures synthesized by co-precipitation method have been hydrothermally functionalized with 8 nm Au NPs and 15 nm Ag nanoparticles. The photocatalytic and electrochemical performance of these structures are investigated. XPS studies show that the composite exhibits a strong interaction between noble metal nanoparticles (NPs) and Zinc oxide nanoflowers. The PL spectra exhibit UV emission arising due to near band edge transition and show that the reduced PL intensities of Au–ZnO and Ag–ZnO composites are responsible for improved photocatalytic activity arising due to increase in defects. Moreover, the presence of Au NPs on ZnO surface remarkably enhances photocatalytic activity as compared to Ag–ZnO and pure ZnO due to the higher catalytic activity and stability of Au NPs. On the other hand, Ag–ZnO-modified glassy carbon electrode shows good amperometric response to hydrogen peroxide (H_2O_2), with linear range from 1 to 20 µM, and detection limit of 2.5 µM (S/N = 3). The sensor shows high and reproducible sensitivity of 50.8 μA cm"−"2 μM"−"1 with a fast response less than 3 s and good stability as compared to pure ZnO and Au–ZnO-based sensors. All these results show that noble metal NPs-functionalized ZnO base nanocomposites exhibit great prospects for developing efficient non-enzymatic biosensor and environmental remediators.Graphical abstractZnO nanoflowers functionalized with noble metal nanoparticles enhance photocatalytic degradation of RhB dye and electrochemical sensing of hydrogen peroxide.

  9. Noble metal nanoparticle-functionalized ZnO nanoflowers for photocatalytic degradation of RhB dye and electrochemical sensing of hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Muhammad [PINSTECH, Nanomaterials Research Group, Physics Division (Pakistan); Sun, Hongyu [Tsinghua University, Laboratory of Advanced Materials and The State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering Beijing, National Center for Electron Microscopy (China); Karim, Shafqat; Nisar, Amjad; Khan, Maaz [PINSTECH, Nanomaterials Research Group, Physics Division (Pakistan); Ul Haq, Anwar [PINSTECH, Non-destructive testing Group (Pakistan); Iqbal, Munawar [University of the Punjab, Centre for High Energy Physics (Pakistan); Ahmad, Mashkoor, E-mail: mashkoorahmad2003@yahoo.com [PINSTECH, Nanomaterials Research Group, Physics Division (Pakistan)

    2016-04-15

    Flower-like hierarchical Zinc oxide nanostructures synthesized by co-precipitation method have been hydrothermally functionalized with 8 nm Au NPs and 15 nm Ag nanoparticles. The photocatalytic and electrochemical performance of these structures are investigated. XPS studies show that the composite exhibits a strong interaction between noble metal nanoparticles (NPs) and Zinc oxide nanoflowers. The PL spectra exhibit UV emission arising due to near band edge transition and show that the reduced PL intensities of Au–ZnO and Ag–ZnO composites are responsible for improved photocatalytic activity arising due to increase in defects. Moreover, the presence of Au NPs on ZnO surface remarkably enhances photocatalytic activity as compared to Ag–ZnO and pure ZnO due to the higher catalytic activity and stability of Au NPs. On the other hand, Ag–ZnO-modified glassy carbon electrode shows good amperometric response to hydrogen peroxide (H{sub 2}O{sub 2}), with linear range from 1 to 20 µM, and detection limit of 2.5 µM (S/N = 3). The sensor shows high and reproducible sensitivity of 50.8 μA cm{sup −2} μM{sup −1} with a fast response less than 3 s and good stability as compared to pure ZnO and Au–ZnO-based sensors. All these results show that noble metal NPs-functionalized ZnO base nanocomposites exhibit great prospects for developing efficient non-enzymatic biosensor and environmental remediators.Graphical abstractZnO nanoflowers functionalized with noble metal nanoparticles enhance photocatalytic degradation of RhB dye and electrochemical sensing of hydrogen peroxide.

  10. Influence of disorder on transfer characteristics of organic electrochemical transistors

    KAUST Repository

    Friedlein, Jacob T.

    2017-07-13

    Organic electrochemical transistors (OECTs) are receiving a great deal of attention as transducers of biological signals due to their high transconductance. A ubiquitous property of these devices is the non-monotonic dependence of transconductance on gate voltage. However, this behavior is not described by existing models. Using OECTs made of materials with different chemical and electrical properties, we show that this behavior arises from the influence of disorder on the electronic transport properties of the organic semiconductor and occurs even in the absence of contact resistance. These results imply that the non-monotonic transconductance is an intrinsic property of OECTs and cannot be eliminated by device design or contact engineering. Finally, we present a model based on the physics of electronic conduction in disordered materials. This model fits experimental transconductance curves and describes strategies for rational material design to improve OECT performance in sensing applications.

  11. Influence of disorder on transfer characteristics of organic electrochemical transistors

    KAUST Repository

    Friedlein, Jacob T.; Rivnay, Jonathan; Dunlap, David H.; McCulloch, Iain; Shaheen, Sean E.; McLeod, Robert R.; Malliaras, George G.

    2017-01-01

    Organic electrochemical transistors (OECTs) are receiving a great deal of attention as transducers of biological signals due to their high transconductance. A ubiquitous property of these devices is the non-monotonic dependence of transconductance on gate voltage. However, this behavior is not described by existing models. Using OECTs made of materials with different chemical and electrical properties, we show that this behavior arises from the influence of disorder on the electronic transport properties of the organic semiconductor and occurs even in the absence of contact resistance. These results imply that the non-monotonic transconductance is an intrinsic property of OECTs and cannot be eliminated by device design or contact engineering. Finally, we present a model based on the physics of electronic conduction in disordered materials. This model fits experimental transconductance curves and describes strategies for rational material design to improve OECT performance in sensing applications.

  12. Influence of disorder on transfer characteristics of organic electrochemical transistors

    Science.gov (United States)

    Friedlein, Jacob T.; Rivnay, Jonathan; Dunlap, David H.; McCulloch, Iain; Shaheen, Sean E.; McLeod, Robert R.; Malliaras, George G.

    2017-07-01

    Organic electrochemical transistors (OECTs) are receiving a great deal of attention as transducers of biological signals due to their high transconductance. A ubiquitous property of these devices is the non-monotonic dependence of transconductance on gate voltage. However, this behavior is not described by existing models. Using OECTs made of materials with different chemical and electrical properties, we show that this behavior arises from the influence of disorder on the electronic transport properties of the organic semiconductor and occurs even in the absence of contact resistance. These results imply that the non-monotonic transconductance is an intrinsic property of OECTs and cannot be eliminated by device design or contact engineering. Finally, we present a model based on the physics of electronic conduction in disordered materials. This model fits experimental transconductance curves and describes strategies for rational material design to improve OECT performance in sensing applications.

  13. Polyelectrolyte Layer-by-Layer Assembly on Organic Electrochemical Transistors

    KAUST Repository

    Pappa, Anna-Maria

    2017-03-06

    Oppositely charged polyelectrolyte multilayers (PEMs) were built up in a layer-by-layer (LbL) assembly on top of the conducting polymer channel of an organic electrochemical transistor (OECT), aiming to combine the advantages of well-established PEMs with a high performance electronic transducer. The multilayered film is a model system to investigate the impact of biofunctionalization on the operation of OECTs comprising a poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) film as the electrically active layer. Understanding the mechanism of ion injection into the channel that is in direct contact with charged polymer films provides useful insights for novel biosensing applications such as nucleic acid sensing. Moreover, LbL is demonstrated to be a versatile electrode modification tool enabling tailored surface features in terms of thickness, softness, roughness, and charge. LbL assemblies built up on top of conducting polymers will aid the design of new bioelectronic platforms for drug delivery, tissue engineering, and medical diagnostics.

  14. Polyelectrolyte Layer-by-Layer Assembly on Organic Electrochemical Transistors

    KAUST Repository

    Pappa, Anna-Maria; Inal, Sahika; Roy, Kirsty; Zhang, Yi; Pitsalidis, Charalampos; Hama, Adel; Pas, Jolien; Malliaras, George G.; Owens, Roisin M.

    2017-01-01

    Oppositely charged polyelectrolyte multilayers (PEMs) were built up in a layer-by-layer (LbL) assembly on top of the conducting polymer channel of an organic electrochemical transistor (OECT), aiming to combine the advantages of well-established PEMs with a high performance electronic transducer. The multilayered film is a model system to investigate the impact of biofunctionalization on the operation of OECTs comprising a poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) film as the electrically active layer. Understanding the mechanism of ion injection into the channel that is in direct contact with charged polymer films provides useful insights for novel biosensing applications such as nucleic acid sensing. Moreover, LbL is demonstrated to be a versatile electrode modification tool enabling tailored surface features in terms of thickness, softness, roughness, and charge. LbL assemblies built up on top of conducting polymers will aid the design of new bioelectronic platforms for drug delivery, tissue engineering, and medical diagnostics.

  15. Electrochemical Synthesis of Polypyrrole, Reduced Graphene Oxide, and Gold Nanoparticles Composite and Its Application to Hydrogen Peroxide Biosensor

    Directory of Open Access Journals (Sweden)

    Baoyan Wu

    2016-11-01

    Full Text Available Here we report a facile eco-friendly one-step electrochemical approach for the fabrication of a polypyrrole (PPy, reduced graphene oxide (RGO, and gold nanoparticles (nanoAu biocomposite on a glassy carbon electrode (GCE. The electrochemical behaviors of PPy–RGO–nanoAu and its application to electrochemical detection of hydrogen peroxide were investigated by cyclic voltammetry. Graphene oxide and pyrrole monomer were first mixed and casted on the surface of a cleaned GCE. After an electrochemical processing consisting of the electrooxidation of pyrrole monomer and simultaneous electroreduction of graphene oxide and auric ions (Au3+ in aqueous solution, a PPy–RGO–nanoAu biocomposite was synthesized on GCE. Each component of PPy–RGO–nanoAu is electroactive without non-electroactive substance. The obtained PPy–RGO–nanoAu/GCE exhibited high electrocatalytic activity toward hydrogen peroxide, which allows the detection of hydrogen peroxide at a negative potential of about −0.62 V vs. SCE. The amperometric responses of the biosensor displayed a sensitivity of 40 µA/mM, a linear range of 32 µM–2 mM, and a detection limit of 2.7 µM (signal-to-noise ratio = 3 with good stability and acceptable reproducibility and selectivity. The results clearly demonstrate the potential of the as-prepared PPy–RGO–nanoAu biocomposite for use as a highly electroactive matrix for an amperometric biosensor.

  16. One-step electrochemical deposition of a graphene-ZrO2 nanocomposite: Preparation, characterization and application for detection of organophosphorus agents

    Energy Technology Data Exchange (ETDEWEB)

    Du, Dan; Liu, Juan; Zhang, Xiao-Yan; Cui, Xiao-Li; Lin, Yuehe

    2011-04-27

    This paper described the preparation, characterization, and electrochemical properties of a graphene-ZrO2 nanocomposite (GZN) and its application for both the enrichment and detection of methyl parathion (MP). GZN was fabricated using electrochemical deposition and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), which showed the successful formation of nanocomposites. Due to the strong affinity to the phosphoric group and the fast electron-transfer kinetics of GZN, both the extraction and electrochemical detection of organophosphorus (OP) agents at the same GZN modified electrochemical sensor was possible. The combination of solid-phase extraction and stripping voltammetric analysis allowed fast, sensitive, and selective determination of MP in garlic samples. The stripping response was highly linear over the MP concentrations ranging from 0.5 ng mL-1 to 100 ng mL-1, with a detection limit of 0.1 ng mL-1. This new nanocomposite-based electrochemical sensor provides an opportunity to develop a field-deployable, sensitive, and quantitative method for monitoring exposure to OPs.

  17. Real-Time and In-Flow Sensing Using a High Sensitivity Porous Silicon Microcavity-Based Sensor.

    Science.gov (United States)

    Caroselli, Raffaele; Martín Sánchez, David; Ponce Alcántara, Salvador; Prats Quilez, Francisco; Torrijos Morán, Luis; García-Rupérez, Jaime

    2017-12-05

    Porous silicon seems to be an appropriate material platform for the development of high-sensitivity and low-cost optical sensors, as their porous nature increases the interaction with the target substances, and their fabrication process is very simple and inexpensive. In this paper, we present the experimental development of a porous silicon microcavity sensor and its use for real-time in-flow sensing application. A high-sensitivity configuration was designed and then fabricated, by electrochemically etching a silicon wafer. Refractive index sensing experiments were realized by flowing several dilutions with decreasing refractive indices, and measuring the spectral shift in real-time. The porous silicon microcavity sensor showed a very linear response over a wide refractive index range, with a sensitivity around 1000 nm/refractive index unit (RIU), which allowed us to directly detect refractive index variations in the 10 -7 RIU range.

  18. Disease-Related Detection with Electrochemical Biosensors: A Review.

    Science.gov (United States)

    Huang, Ying; Xu, Jin; Liu, Junjie; Wang, Xiangyang; Chen, Bin

    2017-10-17

    Rapid diagnosis of diseases at their initial stage is critical for effective clinical outcomes and promotes general public health. Classical in vitro diagnostics require centralized laboratories, tedious work and large, expensive devices. In recent years, numerous electrochemical biosensors have been developed and proposed for detection of various diseases based on specific biomarkers taking advantage of their features, including sensitivity, selectivity, low cost and rapid response. This article reviews research trends in disease-related detection with electrochemical biosensors. Focus has been placed on the immobilization mechanism of electrochemical biosensors, and the techniques and materials used for the fabrication of biosensors are introduced in details. Various biomolecules used for different diseases have been listed. Besides, the advances and challenges of using electrochemical biosensors for disease-related applications are discussed.

  19. Gold nano particle decorated graphene core first generation PAMAM dendrimer for label free electrochemical DNA hybridization sensing.

    Science.gov (United States)

    Jayakumar, K; Rajesh, R; Dharuman, V; Venkatasan, R; Hahn, J H; Pandian, S Karutha

    2012-01-15

    A novel first generation (G1) poly(amidoamine) dendrimer (PAMAM) with graphene core (GG1PAMAM) was synthesized for the first time. Single layer of GG1PAMAM was immobilized covalently on mercaptopropionic acid (MPA) monolayer on Au transducer. This allows cost effective and easy deposition of single layer graphene on the Au transducer surface than the advanced vacuum techniques used in the literature. Au nano particles (17.5 nm) then decorated the GG1PAMAM and used for electrochemical DNA hybridization sensing. The sensor discriminates selectively and sensitively the complementary double stranded DNA (dsDNA, hybridized), non-complementary DNA (ssDNA, un-hybridized) and single nucleotide polymorphism (SNP) surfaces. Interactions of the MPA, GG1PAMAM and the Au nano particles were characterized by Ultra Violet (UV), Fourier Transform Infrared (FTIR), Raman spectroscopy (RS), Thermo gravimetric analysis (TGA), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Cyclic Voltmetric (CV), Impedance spectroscopy (IS) and Differntial Pulse Voltammetry (DPV) techniques. The sensor showed linear range 1×10(-6) to 1×10(-12) M with lowest detection limit 1 pM which is 1000 times lower than G1PAMAM without graphene core. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Preparation and application of a novel electrochemical sensing material based on surface chemistry of polyhydroquinone

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Xueping [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 10080 (China); Wang, Yingkai [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Hu, Chengguo, E-mail: cghu@whu.edu.cn [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 10080 (China); Huang, Jianlin; Chen, Huaixia; Wang, Shengfu [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062 (China); Hu, Shengshui, E-mail: sshu@whu.edu.cn [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 10080 (China)

    2014-07-01

    A new analogue of polydopamine (PDA), i.e., polyhydroquinone (PH{sub 2}Q), was polymerized and its surface chemistry was studied by different ways of characterization. PH{sub 2}Q was produced by the self-polymerization of H{sub 2}Q mediated by dissolved oxygen, and the self-polymerization process was strongly dependent on the type and the pH value of the buffer solutions. PH{sub 2}Q can not only achieve surface hydrophilization of different substrates like polyethylene terephthalate (PET) film, graphite strip, C{sub 12}SH/Au and wax slice, but also possess several unique properties like reversible adsorption, good solubility and low cost. These properties made PH{sub 2}Q an ideal polymeric modifier for the noncovalent functionalization of some nanomaterials. By simply grinding with PH{sub 2}Q, pristine multi-walled carbon nanotubes (MWNTs) can be readily dispersed in water with high solubility and good stability. The resulting MWNT–PH{sub 2}Q composite exhibited excellent electrochemical performance, which was employed for the simultaneous determination of dopamine (DA) and uric acid (UA). - Highlights: • Polyhydroquinone (PH{sub 2}Q) was produced by the self-polymerization of hydroquinone (H{sub 2}Q) mediated by dissolved oxygen. • PH{sub 2}Q can achieve surface hydrophilization of a variety of substrates. • PH{sub 2}Q is an ideal polymeric modifier for the functionalization of multi-walled carbon nanotubes (MWNTs). • The MWNT–PH{sub 2}Q composite can be employed for the simultaneous determination of dopamine (DA) and uric acid (UA)

  1. Electrochemical and spectroscopic study on thiolation of polyaniline

    International Nuclear Information System (INIS)

    Blomquist, Maija; Bobacka, Johan; Ivaska, Ari; Levon, Kalle

    2013-01-01

    Highlights: ► We have thiolated and characterized polyaniline films in order to verify that the thiolation process has taken place. ► Such extensive characterization of thiolation of polyaniline has not previously been reported. ► Thiolation alters the electrochemical properties of polyaniline and the process should be understood. ► Through thiolation many reactive groups may covalently be bound to the polymer backbone. ► Possibility of covalent binding makes polyaniline films an attractive substrate for, e.g., biosensors. -- Abstract: Polyaniline (PANI) is a conducting polymer, easily synthesized and lucrative for many electrochemical applications like ion-selective sensors and biosensors. Thiolated molecules, including biological ones, can be bound by nucleophilic attachment to the polyaniline backbone. These covalently bound thiols add functionality to PANI, but also cause changes in the electrochemical properties of PANI. Polyaniline studied in this work was electropolymerized on glassy carbon electrodes. 2-Mercaptoethanol (MCE) and 6-(ferrocenyl)hexanethiol (FCHT) were used as the thiols to form functionalized films. The films were characterized by cyclic voltammetry (CV), ex situ FTIR and Raman spectroscopies, electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The goal of this work was to confirm the thiolation by spectroscopic methods and to study the impact of thiolation on the electrochemical properties of PANI. Our study showed that thiolated PANI has different electrochemical properties than PANI. Although the thiolation partially reduced the PANI backbone it still remained conductive after the thiolation. Detailed understanding of the thiolation process can be very useful for future applications of PANI

  2. Remote Sensing of Water Quality in Multipurpose Reservoirs: Case Study Applications in Indonesia, Mexico, and Uruguay

    Science.gov (United States)

    Miralles-Wilhelm, F.; Serrat-Capdevila, A.; Rodriguez, D.

    2017-12-01

    This research is focused on development of remote sensing methods to assess surface water pollution issues, particularly in multipurpose reservoirs. Three case study applications are presented to comparatively analyze remote sensing techniquesforo detection of nutrient related pollution, i.e., Nitrogen, Phosphorus, Chlorophyll, as this is a major water quality issue that has been identified in terms of pollution of major water sources around the country. This assessment will contribute to a better understanding of options for nutrient remote sensing capabilities and needs and assist water agencies in identifying the appropriate remote sensing tools and devise an application strategy to provide information needed to support decision-making regarding the targeting and monitoring of nutrient pollution prevention and mitigation measures. A detailed review of the water quality data available from ground based measurements was conducted in order to determine their suitability for a case study application of remote sensing. In the first case study, the Valle de Bravo reservoir in Mexico City reservoir offers a larger database of water quality which may be used to better calibrate and validate the algorithms required to obtain water quality data from remote sensing raw data. In the second case study application, the relatively data scarce Lake Toba in Indonesia can be useful to illustrate the value added of remote sensing data in locations where water quality data is deficient or inexistent. The third case study in the Paso Severino reservoir in Uruguay offers a combination of data scarcity and persistent development of harmful algae blooms. Landsat-TM data was obteined for the 3 study sites and algorithms for three key water quality parameters that are related to nutrient pollution: Chlorophyll-a, Total Nitrogen, and Total Phosphorus were calibrated and validated at the study sites. The three case study applications were developed into capacity building/training workshops

  3. The fabrication, characterisation and electrochemical investigation of screen-printed graphene electrodes.

    Science.gov (United States)

    Randviir, Edward P; Brownson, Dale A C; Metters, Jonathan P; Kadara, Rashid O; Banks, Craig E

    2014-03-14

    We report the fabrication, characterisation (SEM, Raman spectroscopy, XPS and ATR) and electrochemical implementation of novel screen-printed graphene electrodes. Electrochemical characterisation of the fabricated graphene electrodes is undertaken using an array of electroactive redox probes and biologically relevant analytes, namely: potassium ferrocyanide(II), hexaammine-ruthenium(III) chloride, N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), β-nicotinamide adenine dinucleotide (NADH), L-ascorbic acid (AA), uric acid (UA) and dopamine hydrochloride (DA). The electroanalytical capabilities of the fabricated electrodes are also considered towards the sensing of AA and DA. The electrochemical and (electro)analytical performances of the fabricated screen-printed graphene electrodes are considered with respect to the relative surface morphologies and material compositions (elucidated via SEM, Raman, XPS and ATR spectroscopy), the density of electronic states (% global coverage of edge-plane like sites/defects) and the specific fabrication conditions utilised. Comparisons are made between two screen-printed graphene electrodes and alternative graphite based screen-printed electrodes. The graphene electrodes are fabricated utilising two different commercially prepared 'graphene' inks, which have long screen ink lifetimes (>3 hours), thus this is the first report of a true mass-reproducible screen-printable graphene ink. Through employment of appropriate controls/comparisons we are able to report a critical assessment of these screen-printed graphene electrodes. This work is of high importance and demonstrates a proof-of-concept approach to screen-printed graphene electrodes that are highly reproducible, paving the way for mass-producible graphene sensing platforms in the future.

  4. Flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen doped carbon nanotube arrays: In situ electrochemical detection in live cancer cells.

    Science.gov (United States)

    Zhang, Yan; Xiao, Jian; Sun, Yimin; Wang, Lu; Dong, Xulin; Ren, Jinghua; He, Wenshan; Xiao, Fei

    2018-02-15

    The rapidly growing demand for in situ real-time monitoring of chemical information in vitro and in vivo has attracted tremendous research efforts into the design and construction of high-performance biosensor devices. Herein, we develop a new type of flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen-doped carbon nanotube arrays, and explore its practical application in in situ electrochemical detection of cancer biomarker H 2 O 2 secreted from live cancer cells. Our results demonstrate that carbon fiber material with microscale size and fascinating mechanical properties can be used as a robust and flexible microelectrode substrate in the electrochemical biosensor system. And the highly ordered nitrogen-doped carbon nanotube arrays that grown on carbon fiber possess high surface area-to-volume ratio and abundant active sites, which facilitate the loading of high-density and uniformly dispersed gold nanoparticles on it. Benefited from the unique microstructure and excellent electrocatalytic properties of different components in the nanohybrid fiber microelectrode, an effective electrochemical sensing platform based on it has been built up for the sensitive and selective detection of H 2 O 2 , the detection limit is calculated to be 50nM when the signal-to-noise ratio is 3:1, and the linear dynamic range is up to 4.3mM, with a high sensitivity of 142µAcm -2 mM -1 . These good sensing performances, coupled with its intrinsic mechanical flexibility and biocompatibility, allow for its use in in situ real-time tracking H 2 O 2 secreted from breast cancer cell lines MCF-7 and MBA-MD-231, and evaluating the sensitivity of different cancer cells to chemotherapy or radiotherapy treatments, which hold great promise for clinic application in cancer diagnose and management. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. MIP sensors--the electrochemical approach.

    Science.gov (United States)

    Malitesta, Cosimino; Mazzotta, Elisabetta; Picca, Rosaria A; Poma, Alessandro; Chianella, Iva; Piletsky, Sergey A

    2012-02-01

    This review highlights the importance of coupling molecular imprinting technology with methodology based on electrochemical techniques for the development of advanced sensing devices. In recent years, growing interest in molecularly imprinted polymers (MIPs) in the preparation of recognition elements has led researchers to design novel formats for improvement of MIP sensors. Among possible approaches proposed in the literature on this topic, we will focus on the electrosynthesis of MIPs and on less common hybrid technology (e.g. based on electrochemistry and classical MIPs, or nanotechnology). Starting from the early work reported in this field, an overview of the most innovative and successful examples will be reviewed.

  6. Graphene-zinc oxide (G-ZnO nanocomposite for electrochemical supercapacitor applications

    Directory of Open Access Journals (Sweden)

    Murugan Saranya

    2016-12-01

    Full Text Available Graphene-ZnO nanocomposites (G-ZnO were prepared by a facile solvothermal approach. Well, crystalline ZnO nanoparticles with size in the range of 30–70 nm are uniformly deposited on the graphene sheets, as evidenced by different techniques. The electrochemical properties of the prepared nanocomposites were examined by measuring the specific capacitance in 6 M KOH solution using cyclic voltammetry and galvanostatic charge–discharge techniques. G-ZnO nanocomposites showed a good capacitive behavior with a specific capacitance of 122.4 F/g as compared to graphene oxide (2.13 F/g and rGO (102.5 F/g at 5 mV/s scan rate. Results demonstrated that such hybrid materials are promising electrode materials for high-performance supercapacitor applications.

  7. Electrochemical redox reactions in solvated silica sol-gel glass

    International Nuclear Information System (INIS)

    Opallo, M.

    2002-01-01

    The studies of electrochemical redox reactions in solvated silica sol-gel glass were reviewed. The methodology of the experiments with emphasis on the direct preparation of the solid electrolyte and the application ultra microelectrodes was described. Generally, the level of the electrochemical signal is not much below that observed in liquid electrolyte. The current depends on time elapsed after gelation, namely the longer time, the smaller current. The differences between electrochemical behaviour of the redox couples in monoliths and thin layers were described. (author)

  8. Fabrification of electroreduced graphene oxide–bentonite sodium composite modified electrode and its sensing application for linezolid

    International Nuclear Information System (INIS)

    Prashanth, S.N.; Teradal, Nagappa L.; Seetharamappa, J.; Satpati, Ashis K.; Reddy, A.V.R.

    2014-01-01

    Graphene and its composites have attracted considerable attention in synthesis and electrochemical applications. In the present work, we have synthesized and characterized graphene oxide-bentonite composite (GO-BEN) and utilized it to fabricate an electrochemical sensor. For this, the solution of GO-BEN cast on glassy carbon electrode (GCE) was reduced electrochemically in phosphate buffer solution of pH 6 to obtain electrochemically reduced graphene oxide-bentonite composite (ERGO-BEN-GCE). This ERGO-BEN film was used for electrochemical investigation of an oxazolidinone class of antibiotic, linezolid (LIN) for the first time. The electrochemical sensor showed excellent enhancement and adsorptive ability towards the electrooxidation of LIN. LIN exhibited two each of oxidation and reduction peaks on ERGO-BEN film in phosphate buffer of pH 7.0. Effects of accumulation time, pH of solution and scan rate were studied and various electrochemical parameters were evaluated. The plot of pH versus E p gave a slope of 26.2 mV/pH in the pH range of 4.2-8.0 indicating the participation of two electrons and one proton in the electrode process. An adsorptive stripping differential pulse voltammetric method (AdSDPV) was developed for the determination of LIN in bulk, pharmaceutical formulations and urine samples. Adsorptive stripping linear sweep voltammetric (AdSLSV) and differential pulse voltammetric (DPV) methods were also developed and the results were compared. LIN showed linear relationship between the current density and concentration in the range of 0.25 - 31.25 μM with a LOD of 0.0337 μM in AdSDPV method; 0.5 - 31.25 μM with a LOD of 0.100 μM in DPV method and 1.25 - 37.5 μM with a LOD of 0.5461 μM in AdSLSV method respectively. The proposed AdSDPV method was observed to be simple, fast and inexpensive and hence, could be readily adopted for quality control in pharmaceutical products

  9. Nano-bio-sensing

    CERN Document Server

    Carrara, Sandro

    2011-01-01

    This book examines state-of-the-art applications of nano-bio-sensing. It brings together researchers from nano-electronics and bio-technology, providing multidisciplinary content from nano-structures fabrication to bio-sensing applications.

  10. Engineering the bioelectrochemical interface using functional nanomaterials and microchip technique toward sensitive and portable electrochemical biosensors.

    Science.gov (United States)

    Jia, Xiaofang; Dong, Shaojun; Wang, Erkang

    2016-02-15

    Electrochemical biosensors have played active roles at the forefront of bioanalysis because they have the potential to achieve sensitive, specific and low-cost detection of biomolecules and many others. Engineering the electrochemical sensing interface with functional nanomaterials leads to novel electrochemical biosensors with improved performances in terms of sensitivity, selectivity, stability and simplicity. Functional nanomaterials possess good conductivity, catalytic activity, biocompatibility and high surface area. Coupled with bio-recognition elements, these features can amplify signal transduction and biorecognition events, resulting in highly sensitive biosensing. Additionally, microfluidic electrochemical biosensors have attracted considerable attention on account of their miniature, portable and low-cost systems as well as high fabrication throughput and ease of scaleup. For example, electrochemical enzymetic biosensors and aptamer biosensors (aptasensors) based on the integrated microchip can be used for portable point-of-care diagnostics and environmental monitoring. This review is a summary of our recent progress in the field of electrochemical biosensors, including aptasensors, cytosensors, enzymatic biosensors and self-powered biosensors based on biofuel cells. We presented the advantages that functional nanomaterials and microfluidic chip technology bring to the electrochemical biosensors, together with future prospects and possible challenges. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Affinity-Mediated Homogeneous Electrochemical Aptasensor on a Graphene Platform for Ultrasensitive Biomolecule Detection via Exonuclease-Assisted Target-Analog Recycling Amplification.

    Science.gov (United States)

    Ge, Lei; Wang, Wenxiao; Sun, Ximei; Hou, Ting; Li, Feng

    2016-02-16

    As is well-known, graphene shows a remarkable difference in affinity toward nonstructured single-stranded (ss) DNA and double-stranded (ds) DNA. This property makes it popular to prepare DNA-based optical sensors. In this work, taking this unique property of graphene in combination with the sensitive electrochemical transducer, we report a novel affinity-mediated homogeneous electrochemical aptasensor using graphene modified glassy carbon electrode (GCE) as the sensing platform. In this approach, the specific aptamer-target recognition is converted into an ultrasensitive electrochemical signal output with the aid of a novel T7 exonuclease (T7Exo)-assisted target-analog recycling amplification strategy, in which the ingeniously designed methylene blue (MB)-labeled hairpin DNA reporters are digested in the presence of target and, then, converted to numerous MB-labeled long ssDNAs. The distinct difference in differential pulse voltammetry response between the designed hairpin reporters and the generated long ssDNAs on the graphene/GCE allows ultrasensitive detection of target biomolecules. Herein, the design and working principle of this homogeneous electrochemical aptasensor were elucidated, and the working conditions were optimized. The gel electrophoresis results further demonstrate that the designed T7Exo-assisted target-analog recycling amplification strategy can work well. This electrochemical aptasensor realizes the detection of biomolecule in a homogeneous solution without immobilization of any bioprobe on electrode surface. Moreover, this versatile homogeneous electrochemical sensing system was used for the determination of biomolecules in real serum samples with satisfying results.

  12. Impedimetric Thiourea Sensing in Copper Electrorefining Bath based on DC Magnetron Sputtered Nanosilver as Highly Uniform Transducer

    International Nuclear Information System (INIS)

    Mozaffari, S.A.; Amoli, H. Salar; Simorgh, S.; Rahmanian, R.

    2015-01-01

    Highlights: • Fabrication of a novel disposable impedimetric thiourea sensor based on nanostructured Ag film transducer. • Exploiting sputtering as a high-tech method for preparation of highly uniform nanostructured Ag film. • A wonderful combination of nanostructured Ag film and carbon paper substrate as remarkably stable and reproducible sensor for thiourea detection in copper electrorefining bath. • Application of impedimetric assessment for thiourea monitoring due to its rapidity, sensitivity, and repeatability. - Abstract: Highly uniform sputtered nanostructured silver (Nano-Ag) film on the conductive carbon paper (CP) substrate (Nano-Ag/CP) was applied as a novel approach for thiourea (TU) measurement in copper electrorefining bath. Nano-Ag film was achieved by direct current (DC) magnetron sputtering system at the optimized instrumental deposition conditions. Characterization of the surface structure of Nano-Ag film by field emission-scanning electron microscopy (FE-SEM), exhibits uniform Nano-Ag film as an effective transducer for TU sensing. Step by step monitoring of Nano-Ag/CP electrode fabrication were performed using electrochemical methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Fabricated Nano-Ag/CP electrode was used for TU determination using EIS assessment. The impedimetric results show high sensitivity for TU sensing within 2.0–250 ppm.

  13. Electrochemical treatment of an oxide material, application to superconductors, and obtained superconductors

    International Nuclear Information System (INIS)

    Grenier, J.C.; Pouchard, M.; Wattiaux, A.

    1991-01-01

    The present invention describes the electrochemical treatment of a superconductor oxide so as to modify its stoichiometry. These materials comprise in their anionic lattice oxygenated and hydrogenated species. These treated materials are prepared by an electrochemical process in which the oxide is an electrode in a liquid electrolysis. 3 refs., 3 figs

  14. [An application of electrochemical detector to dental pharmacology].

    Science.gov (United States)

    Sakai, J

    1990-03-01

    The electrochemical detection (ECD) is highly sensitive and can distinguish selectively electrochemically active materials. A sensitive and selective ECD is widely used for high-performance liquid chromatography (HPLC) of phenolic compounds, such as catecholamines, indoleamines and phenolic steroids in biological materials. In the present study, the HPLC/ECD system was applied for the simultaneous determination of various dental drugs, such as phenol, guaiacol, m-cresol, o-chlorophenol, p-chlorophenol, m-chlorophenol, eugenol, pyrogallol and resorcin. As a compromise between sensitivity and stability, the applied voltage was set at 1.2 V vs the reference electrode. These drugs were rapidly and selectively separated on a reversed-phase column using 10 mM acetate buffer (pH 4.0)-methanol (7:3, v/v) as a mobile phase. The detection limits of these drugs were determined to be 0.25 pmol per injection. These results imply that the HPLC/ECD method should be capable of determining these dental drugs with high sensitivity. The ECD was also applied to determine the enzyme activity. A highly sensitive and specific assay for alkaline and acid phosphatases and N-acetyl-beta-glucosaminidase in biological materials, such as plasma, saliva and bone, has been established. Phenol, formed enzymatically from the substrate, was determined by HPLC/ECD. The retention time of phenol was 7 min and no other peaks were observed. The method is rapid and sensitive with a detection limit for phenol of as little as 0.5 pmol. Thus, as little as 0.5 microliters of rat plasma or 10 microliters of human saliva is all that is required for both alkaline and acid phosphatase assays. The assay is accurate and reproducible. Using this assay, alkaline and acid phosphatase activities in human saliva and in rat saliva elicited by pilocarpine and isoproterenol were determined. It will be possible to apply this new assay method to extremely small biological samples. Thus, the application of the HPLC

  15. Managing Electrochemical Noise Data by Exception Application of an On Line EN Data Analysis Technique to Data From a High Level Nuclear Waste Tank

    International Nuclear Information System (INIS)

    EDGEMON, G.L.

    2003-01-01

    Electrochemical noise has been used a t the Hanford Site for a number of years to monitor in real time for pitting corrosion and stress corrosion cracking (SCC) mechanisms in high level nuclear waste tanks. Currently the monitoring technique has only been implemented on three of the 177 underground storage tanks on the site. Widespread implementation of the technique has been held back for of a number of reasons, including issues around managing the large volume of data associated with electrochemical noise and the complexity of data analysis. Expert review of raw current and potential measurements is the primary form of data analysis currently used at the Hanford site. This paper demonstrates the application of an on-line data filtering and analysis technique that could allow data from field applications of electrochemical noise to be managed by exception, transforming electrochemical noise data into a process parameter and focusing data analysis efforts on the important data. Results of the analysis demonstrate a data compression rate of 95%; that is, only 5% of the data would require expert analysis if such a technique were implemented. It is also demonstrated that this technique is capable of identifying key periods where localized corrosion activity is apparent

  16. ELECTROCHEMICAL PROMOTED CATALYSIS: TOWARDS PRACTICAL UTILIZATION

    Directory of Open Access Journals (Sweden)

    DIMITRIOS TSIPLAKIDES

    2008-07-01

    Full Text Available Electrochemical promotion (EP of catalysis has already been recognized as “a valuable development in catalytic research” (J. Pritchard, 1990 and as “one of the most remarkable advances in electrochemistry since 1950” (J. O’M. Bockris, 1996. Laboratory studies have clearly elucidated the phenomenology of electrochemical promotion and have proven that EP is a general phenomenon at the interface of catalysis and electrochemistry. The major progress toward practical utilization of EP is surveyed in this paper. The focus is given on the electropromotion of industrial ammonia synthesis catalyst, the bipolar EP and the development of a novel monolithic electropromoted reactor (MEPR in conjunction with the electropromotion of thin sputtered metal films. Future perspectives of electrochemical promotion applications in the field of hydrogen technologies are discussed.

  17. Electrochemical Techniques in Textile Processes and Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Mireia Sala

    2012-01-01

    Full Text Available The textile industry uses the electrochemical techniques both in textile processes (such as manufacturing fibers, dyeing processes, and decolorizing fabrics and in wastewaters treatments (color removal. Electrochemical reduction reactions are mostly used in sulfur and vat dyeing, but in some cases, they are applied to effluents discoloration. However, the main applications of electrochemical treatments in the textile sector are based on oxidation reactions. Most of electrochemical oxidation processes involve indirect reactions which imply the generation of hypochlorite or hydroxyl radical in situ. These electrogenerated species are able to bleach indigo-dyed denim fabrics and to degrade dyes in wastewater in order to achieve the effluent color removal. The aim of this paper is to review the electrochemical techniques applied to textile industry. In particular, they are an efficient method to remove color of textile effluents. The reuse of the discolored effluent is possible, which implies an important saving of salt and water (i.e., by means of the “UVEC Cell”.

  18. Optic Fiber Sensing IOT Technology and Application Research

    Directory of Open Access Journals (Sweden)

    Wenjuan Zeng

    2014-10-01

    Full Text Available The growth of the Internet of Things (IOT industry has become a new mark of the communication domain. As the development of the technology of the IOT and the fiber-optical sensor, the combination of the both is a big question to be discussed, and the fiber-optical IOT also has a good development prospect. This article first introduces IOT’s current status, the key technology, the theoretical frame and the applications. Then, it discusses the classification of the optical fiber sensor as well as the development and its application’s situation. Lastly, it puts the optical fiber sensing technology into the IOT, and introduces a specific application which is used in the mine safety based on the fiber-optical IOT.

  19. Disease-Related Detection with Electrochemical Biosensors: A Review

    Directory of Open Access Journals (Sweden)

    Ying Huang

    2017-10-01

    Full Text Available Rapid diagnosis of diseases at their initial stage is critical for effective clinical outcomes and promotes general public health. Classical in vitro diagnostics require centralized laboratories, tedious work and large, expensive devices. In recent years, numerous electrochemical biosensors have been developed and proposed for detection of various diseases based on specific biomarkers taking advantage of their features, including sensitivity, selectivity, low cost and rapid response. This article reviews research trends in disease-related detection with electrochemical biosensors. Focus has been placed on the immobilization mechanism of electrochemical biosensors, and the techniques and materials used for the fabrication of biosensors are introduced in details. Various biomolecules used for different diseases have been listed. Besides, the advances and challenges of using electrochemical biosensors for disease-related applications are discussed.

  20. Hierarchical oxide-based composite nanostructures for energy, environmental, and sensing applications

    Science.gov (United States)

    Gao, Pu-Xian; Shimpi, Paresh; Cai, Wenjie; Gao, Haiyong; Jian, Dunliang; Wrobel, Gregory

    2011-02-01

    Self-assembled composite nanostructures integrate various basic nano-elements such as nanoparticles, nanofilms and nanowires toward realizing multifunctional characteristics, which promises an important route with potentially high reward for the fast evolving nanoscience and nanotechnology. A broad array of hierarchical metal oxide based nanostructures have been designed and fabricated in our research group, involving semiconductor metal oxides, ternary functional oxides such as perovskites and spinels and quaternary dielectric hydroxyl metal oxides with diverse applications in efficient energy harvesting/saving/utilization, environmental protection/control, chemical sensing and thus impacting major grand challenges in the area of materials and nanotechnology. Two of our latest research activities have been highlighted specifically in semiconductor oxide alloy nanowires and metal oxide/perovskite composite nanowires, which could impact the application sectors in ultraviolet/blue lighting, visible solar absorption, vehicle and industry emission control, chemical sensing and control for vehicle combustors and power plants.