| Project/Area Number |
09555267
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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 | 展開研究 |
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| Research Field |
工業分析化学
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| Research Institution | Keio University |
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Principal Investigator |
SUZUKI Koji Keio University, Fac. Sci & Tech, Professor, 理工学部, 教授 (80154540)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMORI Shinji Nippon koden Kogyo Co., R & D Division, Manager, 開発部, 課長(研究職)
SHICHI Yushi Nissan Arc Co., R & D Division, Manager, 研究部, 表面分析室長(研究職)
KOIKE Yasuhiro Keio University, Fac. Sci & Tech, Professor, 理工学部, 教授 (60161840)
HISAMOTO Hideaki Keio University, Fac. Sci & Tech, Research Associate (00286642)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥13,300,000 (Direct Cost: ¥13,300,000)
Fiscal Year 1999: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 1998: ¥4,300,000 (Direct Cost: ¥4,300,000)
Fiscal Year 1997: ¥4,800,000 (Direct Cost: ¥4,800,000)
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| Keywords | ionophore / medical sensor device / optode probe / chemical sensor / ion-sensing / sensing dye / fiber-optic sensor / オプト-ドプローブ / 光学色素分子 / 微細化光ファイバー |
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| Research Abstract |
There has been interest in developing fiber optical chemical sensors (optodes) that have several advantages over eletroochemical sensors (eletrode) with respect to sensitivity and miniaturization. With the progress in the fibrication techniques of the ultrasmall optical fiber probe tip for NSOM (Near-field Scanning Optical Microscopy), optical fiber chemical sensors with micron or submicron sized sensing probes have been developed in recent years. On the other hand, the development of an ion selective optode device based on a plasticized PVC membrane incorporating sensing materials have attracted much attention, and its response mechanism has also been established by us. The major objective of this study is the fabrication of a miniature chemical sensor probe by coating the optode membrane on the submicron sized tapered probe tips, for application to ion sensing in the medical field. By using this small sensor, the measurement of intracellular chemical concentration gradients of many c
… More
hemical species are possible in biological areas.
Single mode all-silica fibers were tapered to submicron sized tips using a micropipette puller. The pulled fiber probe tips were inserted in the capillary tube, which was filled with tetrahydrofuran (THF) solution of the plasticized PVC membrane components co ィイD1nィエD1taining lipophilic anionic fluorescence dye and neutral ionophore (ex. NaィイD1+ィエD1) using a micromanipulator system. The probe tips were then coated with the optode membrane of a few micron thickness. The 4',5'-dibromofluorescein octadecyl ester and 4-heptadecyl-7-hydroxycoumarin were selected as the lipophilic anionic fluorescence dyes. When the caumarin derivative was used, ratiometric measurements were made using two emission peaks which appeared on each side of the isosbestic point. The argon ion laser was used as the excitation source and fluorescence emissions were detected by the photon counting method. Sample solutions were prepared using chloride salts and buffered using a Na salt or buffered using tris (hydroxymethyl) aminomethane and hydrochloric acid to the appropriate pH values. Using a few micrometer-sized Na+ sensing probe, the fluorescence intensity or fluorescence intensity ratio change upon changing the NaィイD1+ィエD1 concentrations was measured.
In the case where the fluorescein derivative was used, miniaturization of the sensing probe to a 3-micrometer size, which showed a stable response to NaィイD1+ィエD1 ion, was successfully achieved. Compared with the result from the bulk optode (used with a fluorescence spectrophotometer), the dynamic range and detection limit were almost equal to the micrometer-sized optode, and miniaturization of the sensing probe did not affect the response of the sensor. In ratiometry using a coumarin derivative, several problems came from miniaturization such as photobleaching, laser power drift and change in the emission collection efficiency were clearly solved using the dual-emission wavelength ratio. In this case, a sensing probe miniaturized to a 5-micrometer size showed a stable response. The smallest probe size prepared in this study was 1.5 micrometers using a fluorescein derivative. In this case, detection of changes in the fluorescence intensity to NiィイD1+ィエD1 ion was achieved. Less
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