• Membrane Journal
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• v.3 no.2
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• pp.70-78
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• 1993

The permeation of insulin was conducted through glucose oxidase(GOD) immobilized composite membrane composed of poly(vinyl akohol)/chitosan blend and porous polyamide membrane. The permeation coefficient of insulin through GOD-immobilized membrane was in the order of $10^{-6}{\sim}10^{-7}\textrm{cm}^3cm/\textrm{cm}^2sec$. The sensitivity of the composite membrane to the glucose concentration was high in a low glucose concentration resulting from the oxygen depletion from the membrane. The permeation of insulin through composite membrane made of PVA/chitosan and porous polyamide membrane was changed by pH and glucose concentration. The permeability was progressively increasing with the glucose concentration at least up to 500mg%.

• KSBB Journal
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• v.16 no.5
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• pp.459-465
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• 2001

The on-line monitoring technique for the concentrations fo glucose and starch by FIA(Flow Injection Analysis)system was studied. Glucose oxidase(GOD) and amyloglucosidase(AMG) were immboilized on VA-Fpoxy carrier and integrated into the FLA system. The pH, buffer flow rate and temperature were optimized and the effects of salts and metabolites dissolved in the sample on the activity of immobilized enzyme were investigated. GOD-FIA and AMG/GOD-FIA were applied for the on-line monitoring of the glucose and starch in a simulated bioprocess. The on-line measurements of glucose concentrations by GOD-FIA agreed with off-line data well and the AMG/GOD-FIA with single cartidge system took and advantage over the FIA system with two separated cartridges for the on-line monitoring of starch concentrations.

• Journal of Electrical Engineering and Technology
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• v.4 no.1
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• pp.106-110
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• 2009

An amperometric glucose biosensor has been developed using viologen derivatives as a charge transfer mediator between a glucose oxidase (GOD) and a gold electrode. A highly stable self-assembled monolayer (SAM) of thiol-based viologen was immobilized onto the gold electrode of a quartz crystal microbalance (QCM) and GOD was immobilized onto the viologen modified electrode. This biosensor response to glucose was evaluated amperometrically in the potential of -300mV. Upon immobilization of the glucose oxidase onto the viologen modified electrode, the biosensor showed rapid response towards glucose. Experimental conditions influencing the biosensor performance, such as pH potential, were optimized and assessed. This biosensor offered excellent electrochemical responses for glucose concentration below ${\mu}$ mol level with high sensitivity and selectivity and short response time. The levels of the RSDs (<5%) for the entire analyses reflected the highly reproducible sensor performance. A linear calibration range between the current and the glucose concentration was obtained up to $4.5{\times}10^{-4}M$. The detection limit was determined to be $3.0{\times}10^{-6}M$.

• Microbiology and Biotechnology Letters
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• v.7 no.1
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• pp.1-8
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• 1979

A new method for immobilization of glucose oxidate by the aerobic gamma radiation of synthetic monomers was developed. The radiocopolymerization was conducted aerobically at -70 to -8$0^{\circ}C$ with the mixture of several polyfunctional esters, acrylates and native enzyme. The retained activity of immobilized glucose oxidase was about 50 to 55％ when a NK 23G ester, acrylamide-bis and water mixture (1:1:2) in cold toluene treated with 450 krad of gam-ma radiation. The radiation dose did not influence significantly to the enzyme activity. The solvents used to prepare the beads of glucose oxidase and monomers were toluene, n-hexane, petoleum ether and chloroform. 0.05M tris-gycerol (pH 7.0) was a more suitable bugger solution for immobilizing the enzyme than was 0.02M phosphate. Immobilization of glucose oxidase shifted the optimum pH for its reaction from 6.0 to 6.5. The pH profile for the immobilized enzyme showed a broad range of optimum activity while the native enzyme gave a sharp pick for its optimum pH value. The immobilized enzyme reaction temperature was at the range of 30~4$0^{\circ}C$.

• KSBB Journal
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• v.10 no.4
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• pp.468-474
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• 1995

The disposable glucose bio-sensor using composite of CTA and PCL membrane was developed for measurement of glucose. The most effective membrane was composed of CTA/PCL(80/20, w/w) and glutaraldehyde one-step immobilization method ($10{\mu}m$ thickness) for glucose sensor gave the best result among various methods, considering oxygen permeability and electronic sensitivity. A scanning electron micrograph of the cross-section of a typical asymmetric CTA/PCL composite membrane showed that the membrane fused with a dense layer covered with a GOD-glutaraldehyde. Glucose oxidase immoblilized on the membrane showed the linearity between difference of absolute amperometric values and glucose concentrations within 7mM when the GOD immobilized electrode was used. About 35% of activity was remained after 8 days when the tyrosinase was immobilized on CTA/PCL (80/20) membrane.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.47-52
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• 2015

To improve both the GOD immobilization capability and sensitivity of MWCNTs-based biosensor electrode, the electrode was prepared by adding different quantities of GO. The addition of GO increased hydrophilicity and the surface free energy of electrodes for glucose sensing as well as the dispersion of MWCNTs. In addition, the GOD immobilization capability was enhanced and the sensitivity was improved up to $121{\mu}A\;mM^{-1}$ even though having a high $K_m$ value (0.105) when adding 0.05 g GO to 0.05 g MWCNTs. These experimental results were attributed to the fact that the improvement in dispersion stability for MWCNTs, hydrophilicity, and surface free energy of electrode surface due to the addition of GO affected GOD immobilization capability.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.86-87
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• 2007

An amperometric glucose biosensor has been developed using viologen derivatives as electron mediator of glucose oxidase (GOD) at Au electrode. Highly stable self assembled monolayer (SAM) of thiol-based viologen is immobilized onto the Au electrode followed byGOD is immobilized onto the viologen modified electrode. This biosensor response to glucose was evaluated amperometrically in the potential of -300 mV. Upon immobilization of glucose oxidase onto the viologen modified-electrode, the biosensor showed rapid response towards glucose. Experimental conditions influencing the biosensor performance such as, pH, potential were optimized and assessed. This biosensor offered an excellent electrochemical response for glucose concentration below ${\mu}mol$ level with high sensitivity and selectivity and short response time. The levels of the RSD's (< 5 %) for the entire analyses reflected the highly reproducible sensor performance. Using the optimized a linear relationship between current and glucose concentration was obtained up to $4.5{\times}10^{-4}$ M. In addition, this biosensor showed well reproducibility and stability.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.191-194
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• 2004

A novel type of intelligent microcapsule reactor system was prepared. The reactor can recognize pH change in the medea and control reaction rate by itself. For the reactor system, acrylic acid (AA), N-isopropylacrylamide (NIPAM), and glucose oxidase (GOD) were selected as a pH-responsive device, a gating device according and a reaction device, respectively. Poly(NIPAM-co-AA) (P-NIPAM-co-AA) are known to change its hydrophilicity-hydrophobicity due to pH change. They were integrated in a core-shell microcapsule space. GOD was loaded inside the core space and the pores in the outside shell layer were filled with P-NIPAM-co-AA linear grafted chains as pH-responsive gates by plasma graft filling polymerization method. When P-NIPAM-co-AA gates are hydrophilic at high pH value, this microcapsule permits glucose penetration into the core space and GOD reaction proceeds. However, when P-NIPAM-co-AA gates are hydrophobic at low pH value, this microcapsule forbids glucose penetration and GOD reaction will not occur. The accuracy of this concept was examined.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.627-629
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• 2003

In this work fiber-optic biosensor that has been used in medical applications was developed. And we can monitored the concentration of glucose and lactate in blood sample by using developed fiber-optic glucose and lactate sensor. Glucose oxidase(GOD) and Lactate oxidase(LOD) were immobilized by using acrylamide adhesive and zeolite on the tip of the optic fiber.

• KSBB Journal
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• v.32 no.1
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• pp.35-45
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• 2017

In this work the optical fiber glucose and lactate biosensors were developed by using fluorescent dye and enzyme immobilized on the end tip of an optical fiber. 3-Glycidyloxypropyl)methyldiethoxysilane (GPTMS), (3-Aminopropyl) trimethoxysilane (APTMS) and Methyltrimethoxysilane (MTMS) were used to immobilize glucose oxidase (GOD), lactate oxidase (LOD) and ruthenium(II) complex (tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II), $Ru(dpp)_3^{2+}$) as oxygen sensitive fluorescent dye. MTMS sol-gel was an excellent supporting material for the immobilization of $Ru(dpp)_3^{2+}$, GOD, and LOD on the optical fiber. Storage stability of the optical fiber glucose sensor was kept constant over 20 days, while the optical fiber lactate sensor had constant storage stability over 17 days. The optical fiber glucose and lactate biosensors also maintained good operational stability for 20 hours and 14 hours, respectively. The activities of the immobilized enzymes were most excellent at pH 7 and at $25^{\circ}C$. On-line monitoring of glucose and lactate in a simulated process was performed with the optical fiber glucose and lactate biosensors. On-line monitoring results were agreed with those of off-line data measured with high performance liquid chromatography (HPLC).