• Title, Summary, Keyword: enzyme electrode

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A Spontaneous Growth of a Diaphorase Enzyme Layer over a Gold Electrode for the Catalytic Reduction of $NAD^+$

  • Kim, So Hyeong;Yun, Se Ok;Gang, Chan
    • Bulletin of the Korean Chemical Society
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    • v.22 no.11
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    • pp.1192-1196
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    • 2001
  • A diaphorase enzyme electrode for the catalytic reduction of NAD+ , the oxidized form of nicotinamide adenine dinucleotide, has been prepared. The enzyme layer grew spontaneously over an aminoethanethiol self assembled monolayer on a go ld plate electrode. The growth was accomplished by simply dipping the electrode covered by the aminoethanethiol monolayer into a solution containing both glutaraldehyde and diaphorase. We suggested that the glutaraldehyde as a cross-linking reagent was attached to the amino groups of the aminoethanethiol monolayer and the diaphorase enzyme molecules were bound to free aldehyde groups of the glutaraldehyde. Further attachments of the enzyme molecules over the bound enzyme molecules continued with the bridging of the glutaraldehyde. In frequency measurements with a quartz crystal microbalance, the frequency decrease was much more than it was for that of the enzyme monolayer formation, and an enzyme layer thicker than a monolayer was formed. The modified electrode was employed to reduce NAD+ , using diffusional methyl viologen as an electron transfer mediator. The NAD+ was electrocatalytically reduced, and the catalytic current was almost equivalent to that with the multilayered electrode of ten enzyme layers.

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Electrochemical Properties of Polypyrrole-Glucose Oxidase Enzyme Electrode: 1. An Influence of Glucose Oxidase on Redox Behavior of Enzyme Electrode (Polypyrrole-Glucose Oxidase 효소전극의 전기화학적 특서: 1. 효소전극의 산화환원에 대한 Glucose Oxidase의 영향)

  • 김현철;구할본;사공건
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.6
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    • pp.520-525
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    • 2000
  • Glucose oxidase was immobilized in polypyrrole by electrosynthesis. The enzyme had an influence on the redox properties of a complex enzyme electrode. In the cyclic voltammograms of the enazyme electrode new peaks were appeared at the potential around 0.7V vs. Ag/AgCl in additional to the typical peaks for polypyrrole. The more immobilized the stronger the peaks became. During the cycling the pH of electrolyte solution was decreased to about 4.4 The reason for that is to be the proton released from the carboxyl in the glucose oxidase in order to keep on a charge neutrality of the oxidized enzyme. This fact suggests that the new peaks in the voltammograms are caused by the redox of glucose oxidase. In the AC impedance spectrum analysis of the electrode the diffusion of electrolyte anion was limited because of chained structure of the enzyme. The faradic impedance was large since the glucose oxidase is an insulator. Therefore when glucose oxidase is entrapped the enzyme should be limited in amount. Because the growth of the polypyrrole is accompanied both charge transfer and mass transport. For the traditional electrosynthesis that means amount of enzyme present in the electrode is limited to as much as film growable.

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Development of the disposable glucose sensor using Cu/Ni/Au electrode (Cu/Ni/Au 전극을 이용한 일회용 포도당 센서 개발)

  • Lee, Young-Tae;Lee, Seung-Ro
    • Journal of Sensor Science and Technology
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    • v.15 no.5
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    • pp.352-356
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    • 2006
  • In this paper, we developed enzyme electrode of a new form to improve performance of disposable glucose sensor. We could fabricate electrode of Cu/Ni/Au structure which has very low electrical resistance (0.1 $\Omega$) by sticking copper film to plastic film with laminating method and electro-plated nickle and gold on it. The enzyme electrode was completed by immobilizing enzyme on the fabricated electrode. The fabricated glucose sensor has very quick sensing time as 3 seconds, and excellent reproducibility, fabrication yield as well.

Enzyme Sensors Modified with Avidin/Biotin Systembased Protein Multilayers

  • Anzai, Jun-Ichi;Du, Xiao-Yan;Hoshi, Tomonori;Suzuki, Yasuhiro;Takeshita, Hiroki;Osa, Tetsuo
    • Analytical Science and Technology
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    • v.8 no.4
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    • pp.591-596
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    • 1995
  • Enzyme multilayers composed of avidin and biotin-labeled enzymes were prepared on the surface of electrode, through a strong affinity between avidin and biotin (binding constant: ca $10^{15} M^{-1}$). The enzyme multilayers were useful for the improvement of the performance characteristies of enzyme sensors. The output current of the enzyme sensors depended linearly on the number of enzyme layers deposited. Thus, lactate oxidase (LOx) and alcohol oxidase (AlOx) were deposited after being modified with biotin for constructing enzyme sensors sensitive to L-lactate and ethanol respectively. It was also possible to deposit two different kinds of enzymes successively in a single multilayer. The glucose oxidase (GOx) and ascorbate oxidase (AsOx) were built into a multilayer structure on a Platinum electrode. The GOx, AsOx multilayer-modified electrode was useful for the elimination of ascorbic acid interference of the glucose sensor.

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A Sensing of Glucose Solution and Diabetic Serum using Polypyrrole Nanotubules Enzyme Electrode Immobilized Glucose Oxidase (포도당 산화효소를 고정화한 Polypyrrole 나노튜뷸 효소전극의 포도당 용액 및 당뇨병 혈청에 대한 감응특성)

  • Kim, Hyun-Cheol;Gu, Hal-Bon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.6-10
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    • 2001
  • We synthesized polypyrrole (PPy) nanotubules by oxidative polymerization of the pyrrole monomer on the pore of a polycarbonate membrane. The electrochemical behavior was investigated using cyclic voltammetry and AC impedance. The redox potential was about -0.5 V vs. Ag/AgCl reference electrode, while the potential was about 0 V for electro-synthesized PPy film. It is considered as the backbone grows according to the pore wall. Therefore, it is possible to be arranged regularly. That leads to improvement in the electron hopping. The AC impedance plot gave a hint of betterment of mass transport. PPy nanotubules have improved in mass transport, or diffusion. That is because the diffusion occurs through a thin pore wall of PPy nanotubules. The kinetic parameter of PPy nanotubules enzyme electrode with glucose solution was evaluated. The formal Michaelis constant and maximum current calculated by computer were about 23.8 mmol $dm^{-3}$ and $440\;{\mu}A$ respectively. Obviously, an affinity for the substrate and current response of the PPy nanotubules enzyme electrode are rather good, comparing with that of PPy film. What is more, the enzyme electrode is sensitive to blood sugar of a diabetic serum despite an obstruction of ascorbic acid, oxygen, some protein and/or hormone.

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Electrochemical Properties of Polypyrrole Nanotubules Enzyme Electrode Immobilized with Glucose Oxidase (포도당 산화효소가 고정화된 Popyrrole Nanotubules 효소전극의 전기화학적 특성)

  • 김현철;구할본;사공건
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.909-912
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    • 2000
  • We synthesized polypyrrole (PPy) nanotubules by oxidative polymerization of the pyrrole monomer within the pores of a polycarbonate template. The electrochemical behavior was investigated using cyclic voltammetry. The redox potential was about -0.5 V vs. Ag/AgCl reference electrode, while the potential was about 0 V for PPy film. It is considered as the backbone grows according to the pore wall. Therefore, it is possible to be arranged regularly. That leads to improvement in the electron hopping. By electrochemical doping of glucose oxidase (GOx) on PPy nanotubules, an enzyme electrode has been fabricated. The kinetic parameter of biochemical reaction with glucose was evaluated. The formal Michaelis constant and maximum current calculated by computer were about 11.4 mmol $dm^3$ and 170.85 A respectively. Obviously, an affinity for the substrate and current response of the PPy nanotubules enzyme electrode are rather good, comparing with that of PPy film.

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Electrochemical Properties of Tobacco Peroxidase Incorporated Enzyme Electrode Bound with CSM Rubber (CSM 고무로 결합된 담배 과산화효소 고정 효소전극의 전기화학적 특성)

  • Yoon, Kil Joong
    • Applied Chemistry for Engineering
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    • v.25 no.5
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    • pp.538-543
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    • 2014
  • In order to substitute for the marketed horseradish peroxidase, a hydrogen peroxide sensor embedded with tobacco leaf in carbon pastes was constructed and its sensing ability was electrochemically evaluated. Ten and more electrode parameters obtained implied that the enzyme electrode exerts its remarkable specificity quantitatively in the experimental range of potential. Especially the small symmetry factor (${\alpha}$, 0.21) showed that the electrode kinetics is very sensitive to the change of electrode potential. The experimental facts above suggested that our enzyme electrode functions as a hydrogen peroxide sensor normally and tobacco peroxidase can be used in the place of the marketed one as an alternative to marketed ones.

Potentiometric Determination of L-Malate Using Ion-Selective Electrode in Flow Injection Analysis Syste

  • Kwun, In-Sook;Lee, Hye-Sung;Kim, Meera
    • Preventive Nutrition and Food Science
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    • v.4 no.1
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    • pp.79-83
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    • 1999
  • A potentiometric biosensor employing a CO3-2 ion-selective electrode(ISE) and malic enzyme immobilization in al flow injection analysis (FIA) system was constructed. Analytical parameters were optimized for L-malate determination . The CO3-2 -ISE-FIA system was composed of a pump, an injector, a malic enzyme (EC1.1.1.40) reactor, a CO3-2 ion-selective electrode, a pH/mV meter and a recorder. Cofactor NADP was also injected with substrate for theenzyme reaction into the system. Optimized analytical parameters for L-malate determination in the CO3-2 ISE-FIA system were as follows ; flow rate, 14.5ml/hr ; sample injection volume, 100ul; enzyme loading in the reactor, 20 units ; length of the enzyme reactor , 7 cm ; tubing length form the enzyme reactor to the detector as a geometric factor in FIA, 15 cm . The response time for measuring the entire L-malate concentration range (10-2 ~10-5 mol/L ; 4 injections )was <15minutes . In this CO3-2 -ISE-FIA system, the potential differences due to th eformation of CO3-2 by the reaction of malic enzyme on L-malate were correlated to L-malate concentration in the range of 10-2 ~10-5mol/L ; the detection limit was 10-5 mol/L. This potentionmetric CO3-2 ISE--FIA system was found to be useful for L-malate measurement.

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A rapid and easy fabrication of plant-tissue biosensor using rubber binder and its practicability test (고무 결합재를 이용한 식물조직 바이오센서의 간편한 제작과 응용성)

  • Lee, Beom-Gyu;Rhyu, Keun-Bae;Yoon, Kil-Joong
    • Analytical Science and Technology
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    • v.22 no.5
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    • pp.355-359
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    • 2009
  • An enzyme electrode bound by rubber solution was newly constructed and the test of its practicability were carried out. The binder of carbon powder was styrene-butadiene rubber dissolved in toluene and enzyme source was ground tissue of cabbage root. Volatilization of the solvent made the electrode material possess a mechanical robustness and a fast signal appearance. The electrode showed electrochemically irreversible characteristics and a powerful catalytic power (detection limit=$5.0{\times}10^{-5}M$, S/N=2). The double reciprocal plot of signal current and substrate concentration was ideally linear and the symmetry factor and exchange current density of the electrode used in this work were 0.35 and $4.93{\times}10^{-5}Acm^{-2}$ respectively.

Current Characteristics of a Flow Injection Type Enzyme-Sensor as the Variables of a Buffer Velocity, an Enzyme-Substrate Reaction and an Electrode for the Control of a Fermentation Process (완충용액유속, 효소.기질 반응 및 전극봉 요인에 따른 발효공정 제어용 흐름주입식 효소센서의 전류값 특성)

  • Song, Dae-Bin;Jung, Hyo-Seok;Kim, Sung-Tae
    • Journal of Biosystems Engineering
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    • v.32 no.6
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    • pp.455-461
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    • 2007
  • The electric current of a flow injection type enzyme-sensor was measured to confirm the stable operating conditions of the sensor. The current of the sensor was decreased as the buffer solution velocity increased. Under the limitation of the cycle time to be below 10 minutes, the effective ranges of the buffer solution velocity were suggested $0.10{\sim}0.26$, $0.12{\sim}0.24$, $0.1{\sim}0.25$ and $0.05{\sim}0.10\;cm/s$ of 1.0, 1.4, 2.4 and 3.4 mm of the electrode diameters, respectively. As the reaction time of the enzyme and the substrate was increased, the current was decreased because of the dilution between the sample and buffer solution. Therefore, it could be recommended that the reaction time was able to be selected as shortly as possible in consideration of the total cycle time. As the result of the experiments using a different volume ratio of the enzyme to substrate, it was concluded that the substrate had to be mixed with the same amount of the enzyme. The current have increased remarkably in proportion to the electrode diameter under 0.1 cm/s of the buffer solution velocity but there was no difference over 0.1 cm/s of the buffer solution velocity. The cross type arrangement of the electrode was highly suggested for application and machining of the sensor.