scholarly journals The Effect of Multilayer Gold Nanoparticles on the Electrochemical Response of Ammonium Ion Biosensor Based on Alanine Dehydrogenase Enzyme

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Tan Ling Ling ◽  
Musa Ahmad ◽  
Lee Yook Heng ◽  
Toh Chee Seng
Keyword(s):  
Gold Nanoparticles ◽  
Electrode Surface ◽  
Linear Response ◽  
Gold Electrode ◽  
Thiol Group ◽  
Ion Concentration ◽  
Ammonium Ion ◽  
Current Response ◽  
Alanine Dehydrogenase ◽  
Response Range

The use of multilayer of gold nanoparticles (AuNPs) attached on gold electrode surface via thiol chemistry to fabricate an ammonium (NH4+) ion biosensor based on alanine dehydrogenase (AlaDH) was investigated. The approach of the study was based on construction of biosensor by direct deposition of AuNPs and 1,8-octanedithiol (C8-DT) onto the gold electrode surface. For the immobilisation of enzyme, 2-mercaptoethanol (2BME) was first covalently attached to AlaDH via esther bonding and then followed by chemically attached the 2BME-modified AlaDH (2BME-AlaDH) moiety onto the AuNPs electrode via the exposed thiol group of 2BME. The resulting biosensor response was examined by means of amperometry for the quantification ofNH4+ion. In the absence of enzyme attachment, the use of three layers of AuNPs was found to improve the electrochemistry of the gold electrode when compared with no AuNPs was coated. However, when more than three layers of AuNPs were coated, the electrode response deteriorated due to excessive deposition of C8-DT. When AlaDH was incoporated into the AuNPs modified electrode, a linear response toNH4+ion over the concentration range of 0.1–0.5 mM with a detection limit of 0.01 mM was obtained. In the absence of AuNPs, theNH4+ion biosensor did not exhibit any good linear response range although the current response was observed to be higher. This work demonstrated that the incorporation of AuNPs could lead to the detection of higherNH4+ion concentration without the need of dilution for highNH4+ion concentration samples with a rapid response time of <1 min.

scholarly journals An Amperometric Biosensor Based on Alanine Dehydrogenase for the Determination of Low Level of Ammonium Ion in Water

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Tan Ling Ling ◽  
Musa Ahmad ◽  
Lee Yook Heng
Keyword(s):  
Linear Response ◽  
Limit Of Detection ◽  
Colorimetric Method ◽  
Ion Concentration ◽  
Ammonium Ion ◽  
Carbon Paste ◽  
Alanine Dehydrogenase ◽  
Response Range ◽  
Paste Electrode

An amperometric electrochemical biosensor has been developed for ammonium (NH4+) ion detection by immobilising alanine dehydrogenase (AlaDH) enzyme in a photocurable methacrylic membrane made up of poly(2-hydroxyethyl methacrylate) (pHEMA) on a screen-printed carbon paste electrode (SPE). The current detected was based on the electrocatalytic oxidation of nicotinamide adenine dinucleotide reduced (NADH) that is proportional to the consumption ofNH4+ion whilst enzymatic amination of AlaDH and pyruvate is taking place. The biosensor was operated amperometrically at a potential of +0.6 V and optimum pH 7. TheNH4+biosensor demonstrated linear response toNH4+ion concentration in the range of 0.03–1.02 mg/L with a limit of detection (LOD) of 8.52 μg/L. The proposed method has been successfully applied to the determination ofNH4+ion in river water samples without any pretreatment. The levels of possible interferents in the waters were negligible to cause any interference on the proposed method. The analytical performance of the biosensor was comparable to the colorimetric method using Nesslerisation but with much lower detection limit and linear response range at ppb level.

In Operando Detection of the Physical Properties Change of the Interfacial Electrolyte during Li-Metal Electrode Reaction by Atomic Force Microscopy

2020 ◽  
Author(s):  
Mitsunori Kitta
Keyword(s):  
Atomic Force Microscopy ◽  
Energy Dissipation ◽  
Physical Properties ◽  
Electrode Surface ◽  
Electrode Reaction ◽  
Metal Electrode ◽  
Ion Concentration ◽  
Force Microscopy ◽  
Atomic Force ◽  
Discharge Reaction

This manuscript propose the operando detection technique of the physical properties change of electrolyte during Li-metal battery operation.The physical properties of electrolyte solution such as viscosity (η) and mass densities (ρ) highly affect the feature of electrochemical Li-metal deposition on the Li-metal electrode surface. Therefore, the operando technique for detection these properties change near the electrode surface is highly needed to investigate the true reaction of Li-metal electrode. Here, this study proved that one of the atomic force microscopy based analysis, energy dissipation analysis of cantilever during force curve motion, was really promising for the direct investigation of that. The solution drag of electrolyte, which is controlled by the physical properties, is directly concern the energy dissipation of cantilever motion. In the experiment, increasing the energy dissipation was really observed during the Li-metal dissolution (discharge) reaction, understanding as the increment of η and ρ of electrolyte via increasing of Li-ion concentration. Further, the dissipation energy change was well synchronized to the charge-discharge reaction of Li-metal electrode.This study is the first report for direct observation of the physical properties change of electrolyte on Li-metal electrode reaction, and proposed technique should be widely interesting to the basic interfacial electrochemistry, fundamental researches of solid-liquid interface, as well as the battery researches.

scholarly journals Surface Adsorption of the Cancer Biomarker Lysophosphatidic Acid in Serum Studied by Acoustic Wave Biosensor

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4158
Author(s):  
Brian De La Franier ◽  
Michael Thompson
Keyword(s):  
Acoustic Wave ◽  
Lysophosphatidic Acid ◽  
Electrode Surface ◽  
Biological Fluids ◽  
Thiol Group ◽  
Cancer Biomarker ◽  
Specific Adsorption ◽  
Shear Mode ◽  
Serum Samples ◽  
Fouling Reduction

The thickness shear mode acoustic wave device is of interest for the sensing of biomarkers for diseases in various biological fluids, but suffers from the issue of non-specific adsorption of compounds other than those of interest to the electrode surface, thus affecting the device’s output. The aim of this present study was to determine the level of non-specific adsorption on gold electrodes from serum samples with added ovarian cancer biomarker lysophosphatidic acid in the presence of a surface anti-fouling layer. The latter was an oligoethylene molecule with thiol group for attachment to the electrode surface. It was found that the anti-fouling layer had a minimal effect on the level of both adsorption of components from serum and the marker. This result stands in sharp contrast to the analogous monolayer employed for anti-fouling reduction on silica.

Pollen-Shaped Hierarchical Structure for Pressure Sensors with High Sensitivity in an Ultrabroad Linear Response Range

2020 ◽  
Vol 12 (49) ◽  
pp. 55362-55371
Author(s):  
Tingting Zhao ◽  
Li Yuan ◽  
Tongkuai Li ◽  
Longlong Chen ◽  
Xifeng Li ◽  
...  
Keyword(s):  
Hierarchical Structure ◽  
Linear Response ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Response Range ◽  
Linear Response Range

scholarly journals Kinetic studies of HRP adsorption on ds-DNA immobilized on gold electrode surface by EIS and SPR

2010 ◽  
Vol 21 (9) ◽  
pp. 1648-1655 ◽  
Author(s):  
Danielle C. M Ferreira ◽  
Renata K Mendes ◽  
Lauro T Kubota
Keyword(s):  
Electrode Surface ◽  
Gold Electrode ◽  
Kinetic Studies

Effect of surfactants and halide ions on the adsorption and oxidation of homocysteine at the gold electrode

RSC Advances ◽  
2016 ◽  
Vol 6 (55) ◽  
pp. 50315-50321
Author(s):  
Jianying Wang ◽  
Shangshang Zuo ◽  
Cui Lu ◽  
Yanbing Zu ◽  
Zuofeng Chen
Keyword(s):  
Electrode Surface ◽  
Gold Electrode ◽  
Halide Ions

This study demonstrates how adsorptive species including a series of surfactants and halide ions affect the adsorption of Hcy on the electrode surface, as well as how the change of Hcy adsorption affects the oxidation of Hcy.

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