2007 Fiscal Year Final Research Report Summary
Function of DNA/Conducting Polymer Complex Single Molecules with Highly Ordered Structure
| Project/Area Number |
17350089
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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 |
Functional materials/Devices
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| Research Institution | Chiba University |
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Principal Investigator |
KOBAYASHI Norihisa Chiba University, Grtaduate School of Advanced Intagration Science, Professor (50195799)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Nanomaterials / Polymer Structure Property / Conjugated Polymer / Polyaniline / DNA / Single Chain |
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| Research Abstract |
We successfully prepared a DNA/conducting polymer complex with highly-ordered structure. The highly-ordered structure complex showed unique opt-electronic function. It was found that organic light emitting diode (OLED) was successfully demonstrated with this complex. In this research, in ordered to explore innovative function of the complex in a single macromolecular level and to apply a functional molecular wire, we analyzed the molecular structure of DNA highly ordered structure complex with AFM technique and summarized the relation between the molecular structure and electronic properties of the single macromolecular complex.
Before tackling DNA/conducting polymer (polyaniline; PAn) complex, the macromolecular structure of DNA/Ru(bpy)_3^<2+> complex, where lower molar mass Ru(bpy)_3^<2+> was associated with DNA via non-covalent bond, was studied with AFM. A dilute solution of the complex was prepared and cast on mica surface flat in atomic level. From the AFM images of the DNA molecu
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les containing Ru(bpy)_3^<2+> with DNA (phosphate)/ Ru(bpy)_3^<2+> concentration ratio up to 1/1, the DNA complex molecules were entangled to each other forming network structure which could be commonly seen for plain DNA molecules. The height of each fiber was less than 1 nm, indicating the network was formed by single macromolecular DNA complex. Such a kind of networks was not observed in dye-intercalated DNA molecules which formed thick rod and cluster structure. Since DNA/Ru(bpy)_3^<2+> complex shows opt-electronic functions, DNA/Ru(bpy)32+ complex is expected to be a material for functional molecular wire.
With the aim of opt-electronic functional molecular wire, bridging of DNA/Ru(bpy)_3^<2+> and DNA/PAn complex molecules between a pair of electrodes was carried out with dielectrophoretic stretching technique. It is well-known that DNA molecule can be stretched between electrodes by applying high-frequency (>1 MHz) and high-voltage (>1MV/m) ac electric fields to the DNA solution. By modifying the technique and coupling other techniques, we succeeded the bridging of DNA/Ru(bpy)_3^<2+> and DNA/PAn complex molecules between a pair of electrodes. Particularly for DNA/PAn complex, the current between electrodes under a certain bias electric field was higher in DNA/PAn complex than in plain DNA. This result clearly indicates that DNA/conducting polymer complex with highly-ordered structure has unique function in single molecular level and is a potent candidate to realize opt-electronic functional molecular wire. Less
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Research Products
(44 results)
