52300

Sensing and Actuation in Miniaturized Systems

Professor ： Cheng-Hsien  Liu

Students ： Den-Hua Lee

Topics ： Trap DNA/RNA in Microfluidic

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Outline

• The goal• Introduction• Experiments• Results and discussion• Conlusion

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The goal

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What happened in nearing the narrowest part of taper shape microfluidic channel

• The accumulation of flowing DNA Observed near the narrowest part of taper shape microfluidic channel• Both hydro pressure and electric field are applied in the opposite direction• The position and the shape of the accumulated DNA are changed with increasing the electric force and decreasing the hydro pressure

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Shape and size of narrowest part of taper shape channel for DNA/RNA trap.

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Reference 1

Three forces act on DNA

• dc dielectric force

• hydro drag force

• Lorentz force

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Using this technique

The DNA, RNA, Protein, organelles can be trapped, concentrated, and extracted in mixed solution

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Introduction

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Experimental set up

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Reference 2

Structure of the taper shape microchannel

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bovine serum albumin (BSA)

Reference 2

Fluorescence image of nuclei trapping

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Reference 2

Trapping condition of organelles

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Reference 2

Fluorescence image of protein trapping

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Reference 2

Experiments

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The micro channel

• Was made of polydimethylsiloxane (PDMS)

• Long ： 30 mm

• Wide ： 100μm

• Deep ： 10μm

• At the center of the channel, a narrow part of

10μm wide

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The micro channel

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Reference 1

Typical photograph of trap DNA

It shows mode transition with increasing applied voltage.

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Reference 1

Condition map for each trap pattern

• The trap pattern is approximately depend on the ratio of pressure and voltage• The same ratio shows the same pattern

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Reference 1

Numerical simulation of the total force act on each DNA molecule

• Gray area shows the position where the hydro drag force and electric force is nearly balanced• Using the COMSOL Multiphysics software

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Reference 1

Results and Discussion

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The results of three force acted

• The three force ： dc dielectric force, hydro

drag force, Lorentz force.

• The result ： the DEP force is 10-4 times smaller

than the other Lorentz force and hydro drag

force

• The condition for the mode transition was

investigated at various pressure and voltage2008/11/11 21

Actual motion of the trapped DNA

• The dynamic motion of trap molecule

around the balanced position of the two

forces, dc electric force and hydro drag force

• The trap position ： located near the area where

the two forces are balanced

• The balanced position ： move as changing the

ratio of the two forces2008/11/11 22

Conclusion

• The position and shape of trapped DNA by hydro drag force and electric force in taper shape channel was investigated at various condition• The position and the shape changed as a function of the ratio of the electric force and the hydro drag force• The dielectric force is 10-4 times smaller than the other forces, and hydro drag force and Lorentz force were major forces in this trap.

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Reference1 、 Yuzuru Takamura1, Wako Nagasaka1, Kunimitsu Ueno1,Yuichi Tomizawa1, and Eiichi Tamiya1,2 “ MODE TRANSITION & ITS MECHANISM OF RNA/DNA TRAP BY ELECTRIC AND HYDRAULIC FORCE FIELD IN MICROFLUIDIC TAPER SHAPE CHANNEL” uTAS proceeding, p1429-1431 (2007)

2 、 Yuichi Tomizawa, Hiroaki Oose, Kunimitsu Ueno, Md Shameen Ahsans,

Naoki Nagatani, Wako Nagasaka, Eiichi Tamiya, and Yuzuru Takamura, “BIOMOLECULE AND ORGANELLE TRAP USING ELECTRIC AND HYDRODRAG FORCE FIELDS IN TAPER SHAPED MICROCHANNEL”, uTAS proceeding,, p900-902 (2006)

3 、 Carlos Bustamante, Steven B Smith, Jan Liphardt, Doug Smith, “Single-molecule studies of DNA mechanics”, Structural Biology 2000, 10:p279–285

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Thank you