scholarly journals Electrochemical DNA sensors based on spatially distributed redox mediators: challenges and promises

2017 ◽  
Vol 89 (10) ◽  
pp. 1471-1490 ◽  
Author(s):  
Gennady A. Evtugyn ◽  
Anna V. Porfireva ◽  
Ivan I. Stoikov
Keyword(s):  
Conductive Polymers ◽  
Signal Generation ◽  
Dna Aptamers ◽  
Dna Sensors ◽  
Redox Mediators ◽  
Disease Biomarkers ◽  
Redox Active ◽  
Reliable Detection ◽  
Spatially Distributed ◽  
Biomedical Diagnostics

AbstractDNA and aptasensors are widely used for fast and reliable detection of disease biomarkers, pharmaceuticals, toxins, metabolites and other species necessary for biomedical diagnostics. In the overview, the concept of spatially distributed redox mediators is considered with particular emphasis to the signal generation and biospecific layer assembling. The application of non-conductive polymers bearing redox labels, supramolecular carriers with attached DNA aptamers and redox active dyes and E-sensor concept are considered as examples of the approach announced.

Electromechanical Coupling and Signal Distribution of a Circular Cylindrical Shell Coupled With Segmented Sensors

2008 ◽  
Author(s):  
Shih-Lin Huang ◽  
Chin-Chou Chu ◽  
Chien C. Chang ◽  
H. S. Tzou
Keyword(s):  
Cylindrical Shell ◽  
Large Scale ◽  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Circular Cylindrical Shell ◽  
Open Circuit ◽  
Signal Generation ◽  
Signal Distribution ◽  
Shear Design ◽  
Spatially Distributed

The direct piezoelectric effect has long been recognized as an effective electromechanical coupling effect applied to designs of various transducers. Conventional sensor design usually follows three design principles: 1) the tension/compression design, 2) the bending or flexible design and 3) the shear design. These are mostly point-type transducers monitoring responses of discrete locations and, thus, they are not suitable to dynamic spatial monitoring of large-scale distributed structures, such as shells and plates. Accordingly, distributed designs and configurations, such as the segmentation and shaping techniques, have been proposed and evaluated in the last two decades. This study is to evaluate electromechanical coupling and signal generations of a coupled piezoelectric/elastic circular shell structure. A generic open-circuit signal equation of electromechanical coupling and signal generation is presented first, followed by a simplification to signal generation of a circular cylindrical shell case. The total signal generation and its contributing components are analyzed in the modal domain. Spatially distributed modal signals of various shell modes are calculated and the spatial signal distribution illustrates distinct modal characteristics resulting from microscopic modal strain behaviors. Thus, the optimal sensor location(s) for specific shell modes can be identified from the modal signal distribution plots.

Hierarchical bicontinuous structure of redox-active organic composites and their enhanced electrochemical properties

2017 ◽  
Vol 53 (53) ◽  
pp. 7329-7332 ◽  
Author(s):  
Kosuke Sato ◽  
Mirei Arayasu ◽  
Hirotaka Masaki ◽  
Hiroaki Imai ◽  
Yuya Oaki
Keyword(s):  
Electrochemical Properties ◽  
Conductive Polymers ◽  
Redox Active ◽  
Organic Composites ◽  
Bicontinuous Structure

The hierarchical bicontinuous structure of redox-active organic composites of crystalline quinone derivatives and conductive polymers was generated through simultaneous etching of the crystal and polymerization of the monomer.

Enzymes hosted in redox-active ionically cross-linked polyelectrolyte networks enable more efficient biofuel cells

Soft Matter ◽  
2021 ◽  
Author(s):  
Lucy Linders L. Coria Oriundo ◽  
María Lorena Cortez ◽  
Omar Azzaroni ◽  
Fernando Battaglini
Keyword(s):  
Electron Transfer ◽  
Transfer Process ◽  
Biofuel Cells ◽  
Redox Mediators ◽  
Electron Transfer Process ◽  
Redox Active ◽  
Alternative Approach

Redox mediators are pivotal players in the electron transfer process between enzymes and electrodes. We present an alternative approach for redox mediation based on branched polyethyleneimine (BPEI) modified with an...

scholarly journals Recent Achievements in Electrochemical and Surface Plasmon Resonance Aptasensors for Mycotoxins Detection

Chemosensors ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 180
Author(s):  
Gennady Evtugyn ◽  
Anna Porfireva ◽  
Tatjana Kulikova ◽  
Tibor Hianik
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Signal Generation ◽  
Sample Treatment ◽  
Future Trends ◽  
Severe Damage ◽  
Reliable Detection ◽  
Agriculture Products ◽  
Transducer Surface

Mycotoxins are secondary metabolites of fungi that contaminate agriculture products. Their release in the environment can cause severe damage to human health. Aptasensors are compact analytical devices that are intended for the fast and reliable detection of various species able to specifically interact with aptamers attached to the transducer surface. In this review, assembly of electrochemical and surface plasmon resonance (SPR) aptasensors are considered with emphasis on the mechanism of signal generation. Moreover, the properties of mycotoxins and the aptamers selected for their recognition are briefly considered. The analytical performance of biosensors developed within last three years makes it possible to determine mycotoxin residues in water and agriculture/food products on the levels below their maximal admissible concentrations. Requirements for the development of sample treatment and future trends in aptasensors are also discussed.

scholarly journals A Metal Chelator as a Plasmonic Signal-Generation Superregulator for Ultrasensitive Colorimetric Bioassays of Disease Biomarkers

2018 ◽  
Vol 5 (7) ◽  
pp. 1800295 ◽  
Author(s):  
Qian Zhao ◽  
Jiafang Piao ◽  
Weipan Peng ◽  
Jun wang ◽  
Weichen Gao ◽  
...  
Keyword(s):  
Signal Generation ◽  
Disease Biomarkers ◽  
Metal Chelator

scholarly journals Antibody-Electroactive Probe Conjugates Based Electrochemical Immunosensors

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2014 ◽  
Author(s):  
Mateusz Kondzior ◽  
Iwona Grabowska
Keyword(s):  
Horseradish Peroxidase ◽  
Electrochemical Immunosensor ◽  
Signal Generation ◽  
Sensor Signal ◽  
Redox Probe ◽  
Direct Signal ◽  
Redox Active ◽  
Electrochemical Immunosensors ◽  
Analyte Detection ◽  
Transducer Surface

Suitable immobilization of a biorecognition element, such as an antigen or antibody, on a transducer surface is essential for development of sensitive and analytically reliable immunosensors. In this review, we report on (1) methods of antibody prefunctionalization using electroactive probes, (2) methods for immobilization of such conjugates on the surfaces of electrodes in electrochemical immunosensor construction and (3) the use of antibody-electroactive probe conjugates as bioreceptors and sensor signal generators. We focus on different strategies of antibody functionalization using the redox active probes ferrocene (Fc), anthraquinone (AQ), thionine (Thi), cobalt(III) bipyridine (Co(bpy)33+), Ru(bpy)32+ and horseradish peroxidase (HRP). In addition, new possibilities for antibody functionalization based on bioconjugation techniques are presented. We discuss strategies of specific, quantitative antigen detection based on (i) a sandwich format and (ii) a direct signal generation scheme. Further, the integration of different nanomaterials in the construction of these immunosensors is presented. Lastly, we report the use of a redox probe strategy in multiplexed analyte detection.

Common modifications of selenocysteine in selenoproteins

2019 ◽  
Vol 64 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Elias S.J. Arnér
Keyword(s):  
Amino Acids ◽  
Covalent Binding ◽  
Physicochemical Characteristics ◽  
Redox Active

Abstract Selenocysteine (Sec), the sulfur-to-selenium substituted variant of cysteine (Cys), is the defining entity of selenoproteins. These are naturally expressed in many diverse organisms and constitute a unique class of proteins. As a result of the physicochemical characteristics of selenium when compared with sulfur, Sec is typically more reactive than Cys while participating in similar reactions, and there are also some qualitative differences in the reactivities between the two amino acids. This minireview discusses the types of modifications of Sec in selenoproteins that have thus far been experimentally validated. These modifications include direct covalent binding through the Se atom of Sec to other chalcogen atoms (S, O and Se) as present in redox active molecular motifs, derivatization of Sec via the direct covalent binding to non-chalcogen elements (Ni, Mb, N, Au and C), and the loss of Se from Sec resulting in formation of dehydroalanine. To understand the nature of these Sec modifications is crucial for an understanding of selenoprotein reactivities in biological, physiological and pathophysiological contexts.

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