Microfluidic device capable of removing microbubbles in channel by using porous thin film, sample injection device for preventing inflow of bubbles, and method for bonding panel of microfluidic element by using mold-releasing film

1. A sample injection device for preventing inflow of bubbles, the device comprising:

a sample inlet into which a sample is injected;

an upper panel formed with a microfluidic channel including a sample injection channel connecting a main channel to the sample inlet;

a bubble inflow-preventing means formed in a portion of the microfluidic channel to be capable of holding bubbles included in the fluid;

a porous thin film attached to a bottom surface of the microfluidic channel to remove bubbles included in the fluid passing through the microfluidic channel;

a lower panel contacting the upper panel and a bottom surface of the porous thin film and having a path for discharging bubbles, which pass through the porous thin film, to the outside; and

a vacuum-suctioning means for vacuum-suctioning the upper panel and the lower panel such that the microfluidic channel, to which the porous thin film is attached, is attached to the lower panel in a vacuum state, wherein the vacuum-suctioning means comprises a vacuum groove formed on a bottom surface of the upper panel, and a vacuum-suctioning hole communicating with the vacuum groove to apply a vacuum to the vacuum groove so that the microfluidic channel, to which the porous thin film is attached, is attached to the lower panel in a vacuum state,

wherein the bubble inflow-preventing means includes a pillar in the sample injection channel to hold bubbles so as to prevent the bubbles contained in the sample from entering into the main channel, and a bypass channel in front of the pillar in the sample injection channel to bypass the sample so as to introduce the sample into the main channel, and

wherein the bypass channel is located closer to the sample inlet than the pillar in the sample injection channel.

2. The sample injection device of claim 1 , wherein the bypass channel is formed to connect the front and the rear of the pillar-formed sample injection channel.

3. The sample injection device of claim 1 , wherein a plurality of pillars is formed in the width direction or the fluid flow direction of the sample injection channel, and

wherein the sample can flow in the gap between the pillars while bubbles are caught by the pillars.

4. The sample injection device of claim 1 , wherein the pillar is installed at a point at which the bypass channel starts to prevent bubbles from introducing into the bypass channel.

5. The sample injection device of claim 1 , wherein the bypass channel is formed of a curved portion so as to induce the direction of the sample to the bypass channel.

6. The sample injection device of claim 1 , wherein a plurality of the bypass channels are formed in parallel in the sample injection channel.

7. The sample injection device of claim 1 , wherein the microfluidic channel further includes a buffer solution inlet for the injecting a buffer solution and a buffer solution channel connecting the main channel to the buffer solution inlet,

wherein a second pillar is additionally formed in the buffer solution channel, and

wherein a bypass channel is formed in front of the second pillar in the buffer solution channel so as to allow that the buffer solution is bypassed to be introduced into the main channel.

8. The sample injection device of claim 1 , wherein a pattern protrudes from the surface of the lower panel so that a path for discharging the bubbles coming out through the porous thin film to the outside is provided.

9. The sample injection device of claim 8 , wherein the pattern is formed integrally on a surface of the lower panel or by attaching a patterned thin film thereon.

10. The sample injection device of claim 1 , wherein the porous thin film has hydrophobicity so as to block the fluid flowing through the microfluidic channel to pass through the microfluidic channel, but so as to allow only the microbubbles included in the fluid to pass through the microfluidic channel to the lower panel.

11. The sample injection device of claim 10 , wherein the porous thin film is made of a hydrophobic material or has hydrophobicity on a surface of the porous thin film by treatment of a hydrophobic material.

12. The sample injection device of claim 11 , wherein the material of the porous thin film includes at least one selected from the group consisting of polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyimide (PI), polypropylene (PP), poly(methyl methacrylate) (PMMA), polycaprolactone, polystyrene, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, polymer plastic, glass, paper and ceramic.

13. The sample injection device of claim 1 , wherein the vacuum groove is formed to surround the periphery of the microfluidic channel and the porous thin film, and

wherein the vacuum-suctioning hole is formed to communicate with a top surface or a side surface of the upper panel.