2006 Fiscal Year Final Research Report Summary
Study on the flow behavior of DNA polymer dispersion
| Project/Area Number |
17360078
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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 |
Fluid engineering
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| Research Institution | Niigata University |
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Principal Investigator |
HASEGAWA Tomiichi Niigata University, Institute of Science and Technology, Professor (80016592)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRAKASHI Masataka Nagaoka University of Technology, Faculty of Engineering, Professor (60115110)
NARUMI Takatsune Niigata University, Institute of Science and Technology, Associate Professor (20143753)
TAKAHASHI Tsutomu Nagaoka University of Technology, Faculty of Engineering, Associate Professor (20216732)
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| Project Period (FY) |
2005 – 2006
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| Keywords | DNA Polymer / Biomaterial / Micro Flow / Elongational Flow / Fluid Engineering |
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| Research Abstract |
We have investigated elongational or aligning behaviors of DNA polymers in micro flows related to molecular manipulations for DNA analysis. Applicability of DNA polymer dispersions as a functional fluid is also examined in this project. Moreover, it was expected to obtain elemental data for the modeling of molecular motions in polymer dynamics simulations.
In these view points, we have mainly conducted studies with micro flows. Deformation behaviors of DNA polymers in micro channels with an abrupt contraction, an L-shaped corner or a T-shaped joint have been directly observed using a fluorescence microscope. Various deformation or elongation patterns were clarified in such complex flow fields. It was also clarified that more effective extension of DNA polymers was obtained in combined elongational and shear flows than in purely elongational flows. Moreover, since the T-shaped joined channel generates a flow with higher elongational rate than that in the L-shaped corner flow, the T-shaped channel was helpful for the DNA polymer extension. The behaviors of DNA polymers in micro Couette flow were also observed with the same microscope. Polymer extending patterns in a start up flow and relaxation process of DNA polymers after cessation of the flow were observed. It is clarified that the length of DNA polymers decreases exponentially with time in the relaxation process.
Macroscopic properties of DNA polymer solution were also measured utilizing rheometers with mechanical and optical devices. In the measurement of birefringence in steady shear flows, the increase in birefringence and decrease in orientation angle with shear rate increase were obtained. It is considered that these tendency would be related to the extension and alignment of DNA polymers.
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