• 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).

• Journal of Sensor Science and Technology
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• v.15 no.1
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• pp.28-33
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• 2006

Optical-fiber sensors have been developed to determine the concentrations of glucose and lactic acid in blood samples. Fluorescence dye [tris(2,2'-biphenyridine)-ruthenium(II)-chloride (RuBPY)] was entrapped by using a silicon to the unclad tip of a glass optic fiber. Enzymes like glucose oxidase (GOD) and lactate oxidase (LOD) have been immobilized by acrylamide resin adhesive, adsorption with zeolite or covalent bonding with aminopropyl-triethoxysilan. The fiber-optic glucose/lactate sensor was then used to analyze the concentrations of glucose and lactate in blood samples. The results were compared with the results of HPLC analysis and their difference was in error by less then 5 %.

• 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.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.576-583
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• 2023

This study aimed to investigate the impact of enhancing the electrode conductivity and mitigating the production of hydrogen peroxide - a by-product arising from lactate oxidation - on the performance of lactate electrodes. The electrical conductivity of the electrode was improved by modifying the surface of carbon paper with single-walled carbon nanotubes. Catalase was introduced to effectively eliminate the hydrogen peroxide produced during the lactate oxidation reaction. The carbon paper electrode, with simultaneous immobilization of both lactate oxidase and catalase, yielded a current 1.7 times greater than the electrode where only lactate oxidase was immobilized. The electrode in which lactate oxidase and catalase were co-immobilized on the surface of carbon paper modified with single-walled carbon nanotubes, produced a current of 171 µA, which was more than twice as much current as the carbon paper with only lactate oxidase immobilized. The optimized electrode showed a linear response up to lactate concentration of 20 mM, confirming that it can be used as a sensor electrode.

• Analytical Science and Technology
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• v.19 no.6
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• pp.482-489
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• 2006

Two electrode-based lactate biosensor was prepared by immobilizing lactate oxidase (LOD) obtained from pediococcus species in a poly(vinyl alcohol). Hydrogen peroxide ($H_2O_2$) produced by the reaction of lactate and LOD was detected on the Pt-black that was electrochemically deposited on the Au electrode. Sensors fabricated with Pt-black deposited Au electrode provided a high current of $H_2O_2$ oxidation at a substantially lowered applied potential (+300 mV vs. Ag/AgCl), resulting in reduced interferences from easily oxidizable species such as ascorbic acid, acetaminophen, and uric acid. An outer membrane is formulated by adjusting water uptake of hydrophilic polyurethane (HPU). The sensor performance was evaluated in vitro with both flow-through arrangement and static mode. The sensor showed a linear range from 0.1 mM to about 9.0 mM in 0.05 M phosphate buffer (pH 7.6) containing 0.05 M NaCl. Storing the sensors prepared in this work at $4^{\circ}C$ buffer solution while not in use, they provided same electrochemical performance for more than 25 days.

• Journal of Microbiology and Biotechnology
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• v.9 no.3
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• pp.365-367
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• 1999

A fuel cell type biosensor for lactate was developed using a metal-reducing bacterium, Shewanella putrefaciens IR-1. Under the operational conditions, the bacterial cell suspension generated the current without an electrochemical mediator in the presence of lactate. The current was proportional to the lactate concentration up to 30 mM.

• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.238-245
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• 2024

The lactate electrode can be utilized either as an electrode for lactate sensor to monitor the patient's health status, stress level, and athlete's fatigue in real time or lactate fuel cell. In this study, we fabricated a high-performance electrode composed of lactate oxidase, catalase, and mitochondria, and investigated the surface analysis and electrochemical properties of this electrode. Carbon paper modified with single-walled carbon nanotubes (CP-SWCNT) had significantly improved electrical conductivity compared to before modification. The electrode to which lactate oxidase, catalase, and mitochondria were attached (CP-SWCNT-LOx-Cat-Mito) produced a higher current than the electrode to which lactate oxidase and catalase were attached. The amount of reduction current produced by the bilirubin oxidase (BOD)-attached electrode (CP-SWCNT-BOD) was greatly affected by the presence or absence of oxygen in the electrolyte. The fuel cell composed of CP-SWCNT-LOx-Cat-Mito (anode) and CP-SWCNT-BOD (cathode) produced maximum power (29 ㎼/cm²) at a discharge current density of 133 ㎂/cm². From this study, we had proved that mitochondria is essential for improving lactate sensor and fuel cell performance.

• 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.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.22-34
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• 1998

The purpose of this study is to develop biosensor for determination of glucose, lactate, and ethanol in foods and food-stuffs simultaneously. The multiple cathode system was prepared with an oxygen electrode having one anode and hexagonal cathode. Glucose oxidase, mutarotase, lactate oxidase, alcohol oxidase and catalase were used for immobilization to determine glucose, lactate, and ethanol. These components including ethanol were simultaneously determined by the immobilized enzymes in the multiple cathode system. The determination of the components by enzyme sensor was based on the maximum slope of oxygen consumption from enzyme reaction of each sensor part. The response time for analysis was 1 min. The optimum condition for glucose, lactate and ethanol sensor was found to be 0.1 M potassium phosphate buffer, pH 7.0 at $40^{\circ}C$. Interferences of various sugars and organic acids were investigated. Less than 10% of error was found in determination of the components except organic acids. This difference was compensated by the modified equation. This system was confirmed by conventional methods. It was concluded that the multiple cathode system of this study is for an effective method to determine sugar, organic acid, ethanol simultaneously in foods.

• Journal of Biosystems Engineering
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• v.30 no.4 s.111
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• pp.249-253
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• 2005

This study was carried out to develop enzyme biosensor for lactic acid bacteria. Lactic acids produced by lactic acid bacteria (LAB) was measured and good correlation $R^2=0.98$ between LAB count and lactic acids concentration was found. Hydrogen ion produced by L-lactate dehydrogenase (L-LDH) was measured by a potentiometer. Glutamic-pyruvic transminase (GPT) was used for eliminating inhibitor in the reaction. Polyacrylamide gel was used for immobilizing matrix of the sensor. The biosensor was tested and showed good feasibility with $R^2=0.99$ on validation.