2001 Fiscal Year Final Research Report Summary
Bio-impedance imaging by scanning dielectric microscopy
| Project/Area Number |
12680829
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
ASAMI Koji Inst. Chem. Res., Kyoto University Associate Professor, 化学研究所, 助教授 (90127936)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Scanning dielectric microscope / Bio-impedance / Dielectric relaxation / interfacial polarization / biological cell / Cell membrane |
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| Research Abstract |
In this research project, I have improved the scanning dielectric microscope (SDM) for impedance (ordielectric) imaging of biological cells and tissues. Since dielectric images of biological cells and tissues are closely related to their morphology, it is important to compare dielectric images with optical ones directly. Hence, a scanning probe unit was assembled on an inverted optical microscope.
The scanning probe unit consisted of an X-Y stage controlled by a computer and a fine probe electrode attached to the condenser lens unit of the optical microscope. A chamber for samples that had an ITO glass electrode at the bottom was placed on the X-Y stage. For the probe electrode we used a coaxial electrode that was a syringe needle including a Teflon coated Pt wire inside. Impedance measurement was made by the three terminal method that can restrict the measurement to a small area owing to eliminating fringing fields, i.e., the needle (as a guard electrode) and the inner Pt wire (measurement electrode) both have the same potential against the ITO glass (counter electrode).
The performance of the system was tested with well-defined nylon and stainless steel meshes in water, the lateral resolution being around 10 μm using a probe with a Pt wire of 25 μm diameter. As a test biological tissue we measured epithelia of plant leaves including guard cells forming stomata that control gas and water vapor exchange. The results showed that the impedance of guard cells differed from that of the surrounding epithelium cells and that some stomata had high conductance probably due to their opening.
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Research Products
(12 results)
