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Electrochemical Biosensors (electrochemical + biosensor)

Distribution by Scientific Domains

Chemistry	94%

Selected Abstracts

Electrochemical Biosensor for the Detection of Interaction Between Arsenic Trioxide and DNA Based on Guanine Signal

ELECTROANALYSIS, Issue 7 2003
Mehmet Ozsoz
Abstract The interaction of arsenic trioxide (As2O3) with calf thymus double-stranded DNA (dsDNA), calf thymus single-stranded DNA (ssDNA) and also 17-mer short oligonucleotide (Probe,A) was studied electrochemically by using differential pulse voltammetry (DPV) with carbon paste electrode (CPE) at the surface and also in solution. Potentiometric stripping analysis (PSA) was employed to monitor the interaction of As2O3 with dsDNA in solution phase by using a renewable pencil graphite electrode (PGE). The changes in the experimental parameters such as the concentration of As2O3, and the accumulation time of As2O3 were studied by using DPV; in addition, the reproducibility data for the interaction between DNA and As2O3 was determined by using both electrochemical techniques. After the interaction of As2O3 with dsDNA, the DPV signal of guanine was found to be decreasing when the accumulation time and the concentration of As2O3 were increased. Similar DPV results were also found with ssDNA and oligonucleotide. PSA results observed at a low DNA concentration such as 1,ppm and a different working electrode such as PGE showed that there could be damage to guanine bases. The partition coefficients of As2O3 after interaction with dsDNA and ssDNA in solution by using CPE were calculated. Similarly, the partition coefficients (PC) of As2O3 after interaction with dsDNA in solution was also calculated by PSA at PGE. The features of this proposed method for the detection of DNA damage by As2O3 are discussed and compared with those methods previously reported for the other type of DNA targeted agents in the literature. [source]

Multianalyte Electrochemical Biosensor Based on Aptamer- and Nanoparticle-Integrated Bio-Barcode Amplification

CHEMISTRY - AN ASIAN JOURNAL, Issue 2 2010
Xuemei Li Dr.
Abstract In the present work, a signal-on electrochemical sensing strategy for the simultaneous detection of adenosine and thrombin is developed based on switching structures of aptamers. An Au electrode as the sensing surface is modified with two kinds of thiolated capture probes complementary to the linker DNA that contains either an adenosine aptamer or thrombin aptamer. The capture probes hybridize with their corresponding linker DNA, which has prehybridized with the reporter DNA loaded onto the gold nanoparticles (AuNPs). The AuNP contained two kinds of bio-barcode DNA: one is complementary to the linker DNA (reporter), whereas the other is not (signal) and is tagged with different metal sulfide nanoparticles. Thus a "sandwich-type" sensing interface is fabricated for adenosine and thrombin. With the introduction of adenosine and thrombin, the aptamer parts bind with their targets and fold to form the complex structures. As a result, the bio-barcoded AuNPs are released into solution. The metal sulfide nanoparticles are measured by anodic stripping voltammetry (ASV), and the concentrations of adenosine and thrombin are proportional to the signal of either metal ion. With the dual amplification of the bio-barcoded AuNP and the preconcentration of metal ions through ASV technology, detection limits as low as 6.6×10,12,M for adenosine and 1.0×10,12,M for thrombin are achieved. The sensor exhibits excellent selectivity and detectability in biological samples. [source]

Electrochemical Biosensors Based on Layer-by-Layer Assemblies

ELECTROANALYSIS, Issue 18 2006
Wei Zhao
Abstract Layer-by-layer (LBL) assemblies, which have undergone great progress in the past decades, have been used widely in the construction of electrochemical biosensors. The LBL assemblies provide a strategy to rationally design the properties of immobilized films and enhance the performance of biosensors. The following review focuses on the application of LBL assembly technique on electrochemical enzyme biosensors, immunosensors and DNA sensors. [source]

Nanowire-Based Electrochemical Biosensors

ELECTROANALYSIS, Issue 6 2006

Abstract We review recent advances in biosensors based on one-dimensional (1-D) nanostructure field-effect transistors (FET). Specifically, we address the fabrication, functionalization, assembly/alignment and sensing applications of FET based on carbon nanotubes, silicon nanowires and conducting polymer nanowires. The advantages and disadvantages of various fabrication, functionalization, and assembling procedures of these nanosensors are reviewed and discussed. We evaluate how they have been used for detection of various biological molecules and how such devices have enabled the achievement of high sensitivity and selectivity with low detection limits. Finally, we conclude by highlighting some of the challenges researchers face in the 1-D nanostructures research arena and also predict the direction toward which future research in this area might be directed. [source]

Carbon-Nanotube Based Electrochemical Biosensors: A Review

ELECTROANALYSIS, Issue 1 2005
Joseph Wang
Abstract This review addresses recent advances in carbon-nanotubes (CNT) based electrochemical biosensors. The unique chemical and physical properties of CNT have paved the way to new and improved sensing devices, in general, and electrochemical biosensors, in particular. CNT-based electrochemical transducers offer substantial improvements in the performance of amperometric enzyme electrodes, immunosensors and nucleic-acid sensing devices. The greatly enhanced electrochemical reactivity of hydrogen peroxide and NADH at CNT-modified electrodes makes these nanomaterials extremely attractive for numerous oxidase- and dehydrogenase-based amperometric biosensors. Aligned CNT "forests" can act as molecular wires to allow efficient electron transfer between the underlying electrode and the redox centers of enzymes. Bioaffinity devices utilizing enzyme tags can greatly benefit from the enhanced response of the biocatalytic-reaction product at the CNT transducer and from CNT amplification platforms carrying multiple tags. Common designs of CNT-based biosensors are discussed, along with practical examples of such devices. The successful realization of CNT-based biosensors requires proper control of their chemical and physical properties, as well as their functionalization and surface immobilization. [source]

Electrochemical Biosensors for Detection of Biological Warfare Agents

ELECTROANALYSIS, Issue 3 2003
Jasmin Shah
Abstract This review discusses current development in electrochemical biosensors for detection of biological warfare agents. This could include bacteria, viruses and toxins that are aerosoled deliberately in air, food or water to spread terrorism and cause disease or death to humans, animals or plants. The rapid and unequivocal detection and identification of biological warfare agents is a major challenge for any government including military, health and other government agents. Reliable, specific characterization and identification of the microorganism from sampling location, either air, water, soil or others is required. This review will survey different types of electrochemical biosensors has been developed based on the following: i),Immunosensors ii),PCR (DNA base Sensor) iii),Bacteria or whole cell sensor and iv),Enzyme sensor. This article gives an overview of electrochemical biosensor for detection of biological warfare agents. Electrochemical biosensors have the advantages of sensitivity, selectivity, to operate in turbid media, and amenable to miniaturization. Recent developments in immunofiltration, flow injection, and flow-through electrochemical biosensors for bacteria, viruses, and toxin detection are reviewed. The current research and development in biosensors for biological warfare agents detection is of interest to the public as well as to the defense is also discussed. [source]

Protein-based electrochemical biosensor for detection of silver(I) ions,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2010
Sona Krizkova
Abstract Silver(I) ions are extremely toxic to aquatic animals. Hence, monitoring of these ions in the environment is needed. The aim of the present study was to suggest a simple biosensor for silver(I) ions detection. The suggested biosensor is based on the modification of a hanging mercury drop electrode (HMDE) by the heavy metal binding protein metallothionein (MT) for silver(I) ions detection. Metallothionein accumulated for 120 s onto the HMDE surface. After rinsing the electrode, the biosensor (MT modified HMDE) was prepared prior to detection of silver(I) ions. The biosensor was immersed in a solution containing silver(I) ions. These ions were bound to the MT structure. Furthermore, the electrode was rinsed and transferred to a pure supporting electrolyte solution, in which no interference was present. Under these experimental conditions, other signals relating to heavy metals naturally occurring in MT were not detected. This phenomenon confirms the strong affinity of silver(I) ions for MT. The suggested biosensor responded well to higher silver(I) ion concentrations. The relative standard deviation for measurements of concentrations higher than 50,µM was approximately 2% (n,=,8). In the case of concentrations lower than 10,µM, the relative standard deviation increased to 10% (n,=,8). The detection limit (3,signal/noise) for silver(I) ions was estimated as 500,nM. Environ. Toxicol. Chem. 2010;29:492,496. © 2009 SETAC [source]

Platform for Highly Sensitive Alkaline Phosphatase-Based Immunosensors Using 1-Naphthyl Phosphate and an Avidin-Modified Indium Tin Oxide Electrode

ELECTROANALYSIS, Issue 19 2009
Abdul Aziz
Abstract We report a versatile platform for highly sensitive alkaline phosphatase (ALP)-based electrochemical biosensors that uses an avidin-modified indium tin oxide (ITO) electrode as a sensing electrode and 1-naphthyl phosphate (NPP) as an ALP substrate. Almost no electrocatalytic activity of NPP and good electrocatalytic activity of 1-naphthol (ALP product) on the ITO electrodes allow a high signal-to-background ratio. The effective surface covering of avidin on the ITO electrodes allows very low levels of nonspecific binding of proteins to the sensing electrodes. The platform technology is used to detect mouse IgG with a detection limit of 1.0,pg/mL. [source]

DNA Aptamers that Bind to PQQGDH as an Electrochemical Labeling Tool

ELECTROANALYSIS, Issue 11 2009
Yuko Osawa
Abstract We screened DNA aptamers that bind to pyrroquinoline quinone glucose dehydrogenase (PQQGDH) for the development of an electrochemical labeling tool. PQQGDH is an excellent enzyme for the signal amplification of biosensors. We focused on DNA aptamers as labeling agents and tried to select those DNA aptamers that bind to PQQGDH without affecting its enzymatic activity. After 7 rounds of screening, one aptamer was obtained: ,PGa4'. It bound to PQQGDH with specificity and showed no effect on the glucose dehydrogenase (GDH) activity. Moreover, beads labeled with PQQGDH via PGa4 generated an electrical current upon glucose addition. Therefore, we believe that the PGa4 aptamer against PQQGDH may become a powerful labeling tool for electrochemical biosensors. [source]

Poly(neutral red): Electrosynthesis, Characterization, and Application as a Redox Mediator

ELECTROANALYSIS, Issue 12 2008
Rasa Pauliukaite
Abstract The synthesis by electropolymerization, the characterization, and applications of poly(neutral red) (PNR), including as a redox mediator, are reviewed. PNR's high electrical conductivity and its redox characteristics have led to special applications of the polymer, and it has been used for the development of electrochemical and optical sensors. Moreover, the attractive properties of PNR allow it to be applied in the development of electrochemical biosensors. Future perspectives are indicated. [source]

The NADH Electrochemical Detection Performed at Carbon Nanofibers Modified Glassy Carbon Electrode

ELECTROANALYSIS, Issue 14 2007
Adina Arvinte
Abstract In this work, the capability of carbon nanofibers to be used for the design of catalytic electrochemical biosensors is demonstrated. The direct electrochemistry of NADH was studied at a glassy carbon electrode modified using carbon nanofibers. A decrease of the oxidation potential of NADH by more than 300,mV is observed in the case of the assembled carbon nanofiber-glassy carbon electrode comparing with a bare glassy carbon electrode. The carbon nanofiber-modified electrode exhibited a wide linear response range of 3×10,5 to 2.1×10,3,mol L,1 with a correlation coefficient of 0.997 for the detection of NADH, a high specific sensitivity of 3637.65 (,A/M cm2), a low detection of limit (LOD=3,) of 11,,M, and a fast response time (3,s). These results have confirmed the fact that the carbon nanofibers represent a promising material to assemble electrochemical sensors and biosensors. [source]