| Budget Amount *help |
¥10,600,000 (Direct Cost: ¥10,600,000)
Fiscal Year 1998: ¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 1997: ¥6,800,000 (Direct Cost: ¥6,800,000)
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| Research Abstract |
1. Scanning electrochemical microscopy (SECM) was used for localized electrogeneration of hydroxyl radical to create patterns with diaphorase on glass substrates with self-assembled mono-layers (SAMs) of different alkylsilane derivatives. The electrogenerated hydroxyl radical from the probe (microelectrode) of SECM diffused onto the SAM surfaces and degraded the SAMs and removed them from the glass surfaces. When the SAM was hydrophobic, diaphorase patterns were formed on the substrates by dipping the resulting substrate into a diaphorase solution. A SAM with functional terminal groups was also used to immobilize diaphorase via chemical linkage, giving a diaphorase pattern on the substrate.
2. SECM was used for imaging of cellular activity at the single cell level. SECM measurements of SW-480 based on the reduction current of oxygen gave images of respiration activity. The SECM measurements of living cells are particularly suitable to clarify the influence of chemical and physical stimu
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lation at a single cell level. When cyanide ion or nitrophenol was added to the culture medium, the SECM image of the cell became pale, indicating that these species lowers the respiration activity. The permeation of the cellular membrane to cyanide ion was evaluated by the quantitative analysis of the change in the cellular activity. Similarly, SECM was used for estimating the respiration and photosynthetic activity of a single plant cell.
3. SECM was used for estimation of permeation of several redox species through a cell membrane of a single algal protoplast. When the microelectrode is placed close to a membrane which influences the formation of the semi-spherical diffusion region, the redox current becomes lower than that observed in the bulk solution. Since the decrease in the redox current correlates with the permeability of the membrane to redox species, the quantitative analysis of the phenomena affords the permeation coefficient (Pm) for redox species to pass through the membrane. The Pm values for Fe(CN)_6^<-4>, Fe(CN)63-, Co(phen)32_3^<+2>, FMA and hydroquinone were <1x10-4, <1x10-4, 1x10^<-3>, 5x10^<-3> and 2x10^<-2> cm/sec, respectively. Less
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