2005 Fiscal Year Final Research Report Summary
Atomic Force Acoustic Microscopy for Imaging and Characterizing Biological Molecules
| Project/Area Number |
16560058
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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 |
Materials/Mechanics of materials
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| Research Institution | Akita University |
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Principal Investigator |
MURAOKA Mikio Akita University, Faculty of Engineering and Resource Science, Associate Professor, 工学資源学部, 助教授 (50190872)
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| Co-Investigator(Kenkyū-buntansha) |
OKUYAMA Eiki Akita University, Faculty of Engineering and Resource Science, Associate Professor, 工学資源学部, 助教授 (80177188)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Atomic force acoustic microscopy / DNA molecules / DNA chips for genetic diagnoses / Adhesion force / Energy release rate / Concentrated-mass cantilever / Shear force control / Silicon tip |
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| Research Abstract |
The purpose of this study is to develop atomic force acoustic microscopy for detecting mechanical properties of biological molecules together with imaging the molecules. The results are summarized as follows :
1. Immobilization of probe DNA molecules on chips is important in a view point of reliability of genetic diagnoses using DNA chips. Optimization of process of DNA chips requires evaluation of DNA chips for how strong the molecules are fixed on a substrate. As a preliminary research, we developed a method of measuring the bond strength between a DNA molecule and a substrate. Hydrogen bonds stick DNA molecules to silicon tips in water. Therefore silicon tips can pick up and tear the molecules from plastic substrates such polycarbonate chips. The force curve revealed long-range attractive force with roughly constant values at retraction of a cantilever from the substrate. The long-range force reflects the tearing process of molecules. We introduced an energy release rate for the tearing process to determine the adhesion energy per a unit length of a DNA molecule. The analysis clarified the chemical bonding between a polycarbonate substrate and a DNA molecule is mainly hydrogen bonding.
2. In contrast to the measurement in water (result 1), the adhesion between a silicone tip and a DNA molecule on a polycarbonate substrate is weak in air. DNA molecules shield the strong attractive force between a silicon tip and a polycarbonate. This finding can be used for imaging a DNA molecule on a polycarbonate substrate with a surface roughness as a candidate of commercial DNA chips.
3. We developed atomic force acoustic microscopy (AFAM) under a shear force control for imaging of biological molecules. A rod-like gold rod is utilized as a concentrated-mass (CM) for a cantilever. The CM cantilever is efficiently excited to produce a shear force mode of vibration.
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Research Products
(12 results)
