• Journal of Sensor Science and Technology
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• v.24 no.2
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• pp.83-87
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• 2015

In this paper, we fabricated a low-cost glucose sensor with a simpler structure and fabrication process than the existing glucose sensor. The currently used glucose sensor has a three-layer structure with upper, middle, and bottom plates; here, we fabricated a single-layer glucose sensor using only a printing and dispensing process. We successfully fabricated the glucose sensor using a simple method involving the formation of an electrode and insulator layer through a 2- or 3-step printing process on plastic or paper film, followed by the dispensing of glucose oxidase solution on the electrode. Cyclic voltammetry (CV) and cyclic amperometry (CA) measurements were used to evaluate the characteristics of the fabricated single-layer glucose sensor. Also, its sensitivity was analyzed through glucose-controlled blood measurements. Hence, a low-cost single-layer glucose sensor was fabricated with evaluation of its characteristics demonstrating that it has useful application in medicine.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05a
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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.

• BMB Reports
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• v.34 no.5
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• pp.463-471
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• 2001

The bark of Ulmus darvidiana var. japonica Nakai (UDN) has been used for a long time to cure inflammation in oriental medicine. In the present study, two types of extracts, Ulmus water-eluted fraction (UWF) and Ulmus ethanol-eluted fraction (UEF), were prepared from the UDN stem bark, and employed to test the extracts to see if they had anti-oxidative properties against hydroxyl radicals that could alter immune reactivity in mouse immune cells. Deoxyribose assay, DNA nicking assay, and glucose/glucose oxidase assay showed that both fractions had scavenging activity against oxygen free radicals at 50 mg/ml. In addition, hydroxyl radical-mediated apoptosis in mouse thymocytes was not protected by UEF treatment, but the apoptosis was protected by UWF at the same concentration. DNA synthesis and cytokine production that were induced in splenocytes by mitogens (Concanavalin A and lipopolysaccharide) were reduced by the addition of both fractions. These results indicate that both extracts that were prepared from the UDN stem bark have anti-oxidative activities, anti-apoptotic effects, and inhibitory effects on DNA synthesis and cytokine production in mouse immune cell cultures.

• Journal of the Korean Chemical Society
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• v.23 no.3
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• pp.165-174
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• 1979

A purification technique of glucose oxidase was developed. Using the gluconyl-${\omega}$-aminohexyl Sepharose affinity chromatography, it was partially purified 14.6 folds with 79.7% yield. With the combination of the affinity chromatography and Sepharose 6B gel filtration, the enzyme was purified 27.2 folds from the broth with 74.1% yield. The final purified preparation showed 90.83 U of glucose oxidase activity per mg of protein and a single band by 7% polyacrylamide gel electrophoresis. The absorption spectrum and substrate specificity of the enzyme were studied and the fianal preparation showed the optimal pH between 5.6 and 6.0, the optimal temperature at $40^{\circ}C$, $8.5{\times}10^{-3}M$ of $K_m$ for D-glucose, and 3.43 kcal/mole of the activation energy.

• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.778-789
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• 2021

The objective of this study is to investigate the effect of dietary glucose oxidase (GOx) supplementation on the reproductive performance, litter performance, total tract digestibility, and blood profile of lactating sows fed corn- wheat-based diet. A total of twenty multiparous sows (Landrace × Yorkshire) were allocated into one of four treatments with five replicates per treatment. The dietary treatments were as follows: CON (Basal diet), GO1 (basal diet + 200 U GOx/kg), GO2 (basal diet + 300 U GOx/kg), GO3 (basal diet + 400 U Gox/kg). Dietary GOx supplementation did not affect lactating sow's reproduction performance as well as body weight, backfat thickness, and body condition score during pre and post farrowing, and at weaning (p > 0.05). However, after farrowing to weaning period lactating sow's fed GOx supplement has linearly (p = 0.0196) decreased the bodyweight loss. While, there were no effects (p > 0.05) observed on sows backfat thickness loss, average daily feed intake, and estrus interval among treatment groups. Dietary supplementation of GOx has linearly improved the body weight gain (p = 0.049) and average daily gain (p = 0.040) of suckling piglets. The total tract digestibility of dry matter and nitrogen was linearly increased with the graded level of GOx supplement. Also, a linear effect was observed on the glucose and superoxide dismutase of blood profile with the dietary inclusion of GOx. In summary, our finding indicates that the dietary inclusion of GOx supplement with corn- wheat-based diet had a beneficial effect on the nutrient digestibility and blood profile of lactating sows and improved the growth performance of suckling piglets.

• Journal of the Semiconductor & Display Technology
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• v.19 no.4
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• pp.116-120
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• 2020

In this paper, we developed an electrochemical glucose sensor strip using a paper substrate. The paper glucose sensor strip is eco-friendly because it uses paper as a substrate, and it has the advantage that it can be manufactured only with four printing, drying and cutting processes. The paper glucose sensor is significantly simplified by the production process than the conventional glucose sensors because the production of only four printing on the paper substrate. In this paper, eco-friendly tracing paper was used to develop a paper glucose sensor strip, and screen-printing technology was used to form a carbon/silver electrode, insulating layer and glucose oxidase(GOD) layer. The developed paper glucose sensor strip has a flat structure with a size of 30 × 4.6 ㎟, and blood injection is a type of direct contact with the exposed enzyme layer above the strip. In this paper, the performance of paper glucose sensor strips was evaluated by analyzing the cyclic voltammetry(CV) and chronoamperometry(CA) characteristics.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.248-253
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• 2004

To scrutinize the physiological diversity by BIOLOG microplate, the carbon source utilization patterns of 168 strains of oligotrophic bacteria and 132 strains of psychrotrophic bacteria isolated from Lake Baikal during 2000 and 2002 were investigated. Eighty-six percent (56 strains) of oxidase test positive group (GN-NENT group) and 89 % (92 strains) of oxidase test negative group (GN-ENT group) among oligotrophic bacteria, and 82% (85 strains) of oxidase test negative group among psychrotrophic bacteria were able to utilize $\alpha$-D-glucose as a sole-carbon-source, and 93% (26 strains) of oxidase test positive group among psychrotrophic bacteria were able to utilize bromosuccinic acid as a sole-carbon-source. However, most strains except few oligotrophic bacteria with oxidase test negative group were not able to utilize $\alpha$-D-lactose as a sole-carbon-source. Most dominant genus among 300 strains was Pseudomonas (49 strains). Other dominant genera belonged to Salmonella, Serratia, Buttiauxella, Pantoea, Yersinia, Brevundimonas, Hydrogenophaga, Photorhabdus, Sphingomonas, and Xenorhabdus. Our results by BIOLOG identification system were able to provide basic data to determine community-level carbon source utilization patterns and to accomplish the efficient and reliable identification for microbial community structure in Lake Baikal.

• Journal of Sensor Science and Technology
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• v.27 no.3
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• pp.156-159
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• 2018

We developed a glucose sensor using glucose dehydrogenase flavin adenine dinucleotide (GDH-FAD). The structure of the three-layer glucose sensor was simplified, in which a single-layer design was used to lower the unit cost, and GDH-FAD was used to increase the measurement reliability. GDH-FAD has less impact on the 20 interfering substances that affect blood glucose measurement, such as galactose and maltose compared to glucose oxidase (GOD), and is not affected by the oxygen saturation; therefore, it is possible to measure both arterial or venous blood and thus less susceptibility to hematocrit. In this study, we developed a single-layer glucose sensor strip with low hematocrit effect using the GDH-FAD enzyme, and measured and evaluated the performance.

• Journal of the Korean Electrochemical Society
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• v.23 no.3
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• pp.66-72
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• 2020

In this study, the development of biosensors capable of bi-enzyme reactions by including Horseradish peroxidase and glucose oxidase was carried out for detection of glucose. The sensors were manufactured using electro deposition method to reduce production time, and screen printed electrodes (SPE) were used to produce economical sensors. To check the bienzyme effect, the sensor was compared and analyzed with single enzyme biosensor. The characteristics of the sensor were evaluated using scanning electron microscopy(SEM), cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), chronoamperometry(CA), and flow injection analysis(FIA). Analysis results from SEM, CV and EIS confirmed that the enzymes are well fixed to the electrode surface. In addition, it was confirmed that bi-enzyme biosensors manufactured from the CA method improved signal performance by 200% compared to single enzyme biosensors. From this results, we were able to explain that HRP and GOD react catalyzed to each other. And the results of FIA showed that the intensity of each current signal was constant when the same concentration of glucose was injected four times. In addition, by analyzing the intensity of current signals for glucose concentrations, the biosensors manufactured in this study showed excellent trends in signal sensitivity, reproducibility and stability.

• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.68-75
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• 1998

The overproduction and high level secretion of Glucose Oxidase (GOD) from A. niger in S. cerevisiae was carried out by cloning GOD gene. For this purpose, using two different strong promoters (ADH1 promoter, GAL10 promoter) and signal sequences (${alpha}$-MF signal sequence of S. cerevisiae and ${alpha}$-amylase signal sequence of A. oryzae) and GAL7- and GOD terminator, four expression vectors were constructed. All the expression vectors were transformed in S. cerevisiae 2805 using auxotroph method. By the flask culture, transformants of pGAL expression vector series containing GAL 10 promotor showed much higher GOD productivity than transformants of pADH expression vector series containing ADH1 promoter Transformants of pGALGO2 containing GAL10 promotor and ${alpha}$-amylase signal sequence has shown the best productivity of GOD ($GOD_{total}$: 10.3 unit/mL, $GOD_{ex}$: 8.7 unit/mL) at 115 hr. This value was three fold higher than that of pGALGO1 containing GAL 10 promotor and ${alpha}$-MF signal sequence, even if the same promotor was involved. Through the ${alpha}$-amylase signal sequence of A. oryzae, GOD was secreted much more than the case of ${alpha}$-MF signal sequence from S. cerevisiae. These results suggest that signal sequence may play a important roles in not only the secretion but also the overproduction of foreign protein. Secretion rate of GOD in pGALGO1 and pGALGO2 was 89% and 84%, respectively, Because of the overglycosylation in S. cerevisiae the molecular weight of recombinant GOD in S. cerevisiae was much larger (250 kDa) than that of nature GOD in A. niger (170 kDa).