| Project/Area Number |
08458282
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biomedical engineering/Biological material science
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| Research Institution | Tohoku University |
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Principal Investigator |
ANZAI Jun-ichi Tohoku University, Faculty of Pharmaceutical Sciences, Professor, 薬学部, 教授 (40159520)
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| Co-Investigator(Kenkyū-buntansha) |
MAEHARA Kazuhira Fukushima Medical College, School of Medicine, Associate Professor, 医学部, 助教授 (90181817)
KASHIWAGI Yoshitomo Tohoku University, Faculty of Pharmaceutical Sciences, Lecturer, 薬学部, 助手 (50204384)
SUZUKI Iwao Tohoku University, Faculty of Pharmaceutical Sciences, Assistant Professor, 薬学部, 講師 (30226493)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥7,800,000 (Direct Cost: ¥7,800,000)
Fiscal Year 1997: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1996: ¥5,300,000 (Direct Cost: ¥5,300,000)
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| Keywords | composite membrane / multilayr membrane / biosensor / platinum electrode / enzyme membrane / biotin / avidin / 水晶振動子 |
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| Research Abstract |
It is important to develop interference-free biosensors for their medical applications. In this study, the elimination of ascorbate (Vitamin C) interference of lactate biosensors was examined based on composite enzyme membranes. In order to prepare the composite membranes, lactate oxidase (LOx) and ascorbate oxidase (AOx) were first modified with biotion and the modified enzymes were built into the multilayr membranes together with avidin by depositing the enzyme and avidin alternately. The multilayr structure of the enzymes was characterized based on spectrophotometry and microgravimetry.
The optimum loading of LOx and AOx and the effects of the deposition sequence were elucidated. Since ascorbate can be oxidized easily at the electrode surface (+0.6V), the lactate sensor equipped with only LOx suffered from the disturbance originating from 0.1 mM ascorbate (i.e., physiological level in blood) significantly (ca.20%). In other words, it is impossible to determine lactate in human blood with this sensor. In contrast, the lactate sensors modified with the composite membrane of LOx and AOx were not sensitive to 0.1 mM ascorbate in the concentration range of 0.1 mM lactate or higher. The ratio of LOx : AOx=10 : 1 was enough for the elimination of ascorbate interference. Because of low stability of AOx, it is realistic to use the composite membrane of LOx : AOx=1 : 1. Virtually no effect was observed for the deposition sequence of LOx and AOx. It became clear the lactate sensors modified with LOx and AOx composite membrane can be used for the determination of lactate in blood. Streptavidin and deglycosylated avidin can be also used for the construction of the composite membranes.
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