KR20070099752A - Device for delaying capillary flow and method for delaying capillary flow using the same - Google Patents

Abstract

A device for delaying a capillary flow and a method for delaying the capillary flow using the same are provided to adjust the delay time of capillary flow by adjusting the pattern shape and ratio of material having different chemical attraction from water in a part of a micro channel. In a device for delaying a capillary flow, hydrophilic surfaces(30) and hydrophobic surface(40) are repeatedly and alternately arranged in a micro channel(10) by patterning hydrophobic materials in a part of the micro channel. The hydrophilic micro channel is made of plastic, glass, silicon, metal, and the like. The hydrophobic materials are patterned by a method of photo-depositing self-assembled monolayer with a mask, a method of depositing plasma, a method of transferring hydrophobic ink with a printer, or a method of micro contact printing. The pressure of fluid is adjusted by adjusting the ratio of hydrophobic materials in the hydrophobic channel, and the whole flow speed is lowered by inducing the pressure close to zero.

Description

Device for Delaying Capillary Flow and Method for Delaying Capillary Flow Using the Same

1 is a schematic diagram illustrating a capillary flow retardation device in which a hydrophobic pattern is formed.

2 is a graph showing the pressure change in the capillary flow retardation device according to the present invention.

3 is a cross-sectional view of the microchannel in which the hydrophobic pattern is inserted.

4 is a schematic diagram of a hydrophobic pattern according to Example 1 of the present invention.

5 is a schematic diagram of a microfluidic device according to Embodiment 1 of the present invention.

6 is a view showing a method of manufacturing a hydrophobic pattern according to Example 1 of the present invention.

7 is a graph showing the delay time of capillary flow according to the shape of the hydrophobic pattern in the capillary flow delay device according to the present invention.

8 is a view showing a change in capillary flow according to Example 1 of the present invention.

9 is a view showing a microfluidic device according to a second embodiment of the present invention.

10 is an optical micrograph of the hydrophobic pattern of the microfluidic device according to Example 2 of the present invention.

11 is a view showing a change in capillary flow according to the second embodiment of the present invention.

The present invention relates to a capillary flow retardation device and a capillary flow retardation method using the same. More specifically, the hydrophobic surface and the hydrophilic surface are repeatedly arranged by repeatedly patterning a material having different affinity with water in a part of the microchannel. It relates to a capillary flow delay device and a capillary flow delay method using the same.

Control of microfluidic flow in microchannels is an essential element in various microfluidic systems, and various methods such as mechanical pumps and valves, electroosmotic and electrochemical methods are currently being studied. In particular, David J. Beebe et al. Proposed a method to control the flow of flow by patterning hydrophobic self-assembled monolayers (SAMs) into microchannels through photopatterning (Zhao, B. et. al ., Science , 1023 (291), 2001), MA Burns, et al ., proposed a method for patterning hydrophobic materials on one side of microchannels to stop flow and meter nanoliter fluids (Handique, K). et al., Anal.Chem., 4100 (72), 2000). In addition, Korean Patent Publication No. 2004-013731 discloses a fluid control element capable of locally regulating the speed of a fluid by partially forming a hydrophobic material pattern on a capillary tube wall of a hydrophilic material.

However, the above studies are meaningful in that they suggest a method of controlling the flow by appropriately patterning various surface energies on the surface of the microchannel, but external pressure must be applied to resume the flow stopped by the hydrophobic pattern. There is a problem that additional operation such as is required.

Further, Japanese Patent Application Laid-open No. Hei 10-311827 discloses a test tool provided with a hydrophobic region between the first and second hydrophilic regions to move blood to a reagent for reaction. There is a problem that it is difficult to control a variety of capillary flow.

On the other hand, US Patent 6,271,040 discloses a method for delaying capillary flow by a hydrophobic material, but according to the patent, the protein in the sample is adsorbed on the hydrophobic surface, the surface is changed to hydrophilic, wherein the protein is hydrophobic surface The reaction time of the sample is determined by the degree of adsorption and the degree of hydrophobicity of the surface. However, the above method has a problem in that a sample such as a protein for changing the hydrophobic surface to be hydrophilic must be included in the fluid.

Therefore, in the art, there is an urgent need for the development of a capillary flow delay method, which is simpler than the conventional capillary flow control method and which can freely adjust the capillary flow delay time.

Accordingly, the present inventors have made intensive efforts to develop a capillary flow control method capable of freely and conveniently adjusting the capillary flow delay time, and thus, the present invention has been completed.

After all, the main object of the present invention is to provide a capillary flow retardation device and a method of manufacturing the same, which can easily and freely adjust the delay time of capillary flow.

Another object of the present invention is to provide a microfluidic device manufactured using the capillary flow retardation device.

In order to achieve the above object, in the first embodiment, the hydrophobic material is repeatedly patterned such that the hydrophilic surface and the hydrophobic surface are alternately arranged at the center of the microchannel of the hydrophilic material. Provide (device).

In the first embodiment of the present invention, the hydrophilic material microchannel may be characterized in that the glass or polymethymethacrylate (PMMA), the hydrophobic material may be characterized in that the PDMS (polydimethylsiloxane). In addition, in order to form a virtual wall surface, the hydrophobic material may be additionally patterned on the outer portion of the microchannel.

The present invention also provides a capillary flow retardation device according to a first embodiment of the present invention comprising the step of repeatedly patterning a hydrophobic material such that the hydrophilic surface and the hydrophobic surface are alternately arranged at the center of the microchannel of the hydrophilic material. It provides a method of manufacturing).

In the first embodiment of the present invention, in order to variously control the capillary flow delay time, it is characterized in that the patterning ratio of the hydrophobic material may be changed, the patterning method of the hydrophobic material is a light deposition method, plasma deposition It can be characterized in that it is selected from the group consisting of a method, a transfer method of the ink using a printer, and a micro contact printing method.

In another aspect, the present invention provides a capillary flow retardation device characterized in that a hydrophilic material is repeatedly patterned so that a hydrophilic surface and a hydrophobic surface are alternately arranged at a central portion of a microchannel of a hydrophobic material. to provide.

In a second embodiment of the present invention, in order to form a virtual wall surface, it may be characterized in that the hydrophilic material is additionally patterned on the outer portion of the micro-channel.

The present invention also provides a capillary flow retardation device according to a second embodiment of the present invention comprising the step of repeatedly patterning a hydrophilic material such that the hydrophilic surface and the hydrophobic surface are alternately arranged at the center of the microchannel of the hydrophobic material. It provides a method for manufacturing a device).

According to a second embodiment of the present invention, in order to variously control the capillary flow delay time, the patterning ratio of the hydrophilic material may be changed, and the patterning method of the hydrophilic material may be a photodeposition method or a plasma deposition method. It can be characterized in that it is selected from the group consisting of a method, a transfer method of the ink using a printer, and a micro contact printing method.

In the capillary flow delay device according to the first and second embodiments of the present invention, the patterning shape may be arranged in the flow direction of the fluid, wherein the patterning shape is in a direction perpendicular to the flow of the fluid. It may be characterized as being arranged. In addition, the material of the microchannel may be selected from the group consisting of polymer, glass, quartz, silicon, metal, ceramic, porous membrane and the like.

The present invention also provides a method for delaying capillary flow, using the capillary flow delay device according to the first or second embodiment.

The present invention also has a hydrophilic or hydrophobic cover substrate attached to the capillary flow delay device according to the first embodiment, and a spacer for adjusting the depth of the microchannel between the capillary flow delay device and the hydrophilic or hydrophobic cover substrate. Provides a Microfluidic Device

The present invention also has a hydrophilic or hydrophobic cover substrate attached to the capillary flow delay device according to the second embodiment, and a spacer for controlling the depth of the microchannel between the capillary flow delay device and the hydrophilic or hydrophobic cover substrate is provided. Provided is a microfluidic device mounted.

In the present invention, the material of the hydrophilic cover substrate may be any one or more selected from the group consisting of polymer, glass, quartz, silicon, metal, ceramic, porous membrane and the like.

Hereinafter, the present invention will be described in detail.

The capillary flow retardation device of the present invention can be manufactured by patterning a material having a different affinity with water on a part of the microchannel so that the hydrophilic surface and the hydrophobic surface are repeatedly arranged. Hereinafter, although only a method of manufacturing a capillary flow retardation device by patterning a hydrophobic material in a hydrophilic microchannel, it can be applied to the case where the microchannel is hydrophobic and the material to be patterned is hydrophilic. Will be self-evident.

1 shows a capillary flow retardation device characterized in that the hydrophobic surface 30 and the hydrophilic surface 40 are repeatedly arranged in the channel by repeatedly patterning the hydrophobic material 30 in the hydrophilic microchannel portion 10. will be.

The hydrophilic microchannels can be a variety of materials such as plastic, glass, silicon, metal, and the like. On the other hand, as a method of patterning the hydrophobic material, a method of photodepositing a SAM (self-assembled monolayer) using a mask, plasma deposition of the hydrophobic material, transfer of the hydrophobic ink using a printing machine, or patterning of the hydrophobic material by micro contact printing Various methods are possible.

In general, when a fluid enters a microchannel consisting of a hydrophilic surface, positive pressure is generated inside the fluid due to surface tension, and capillary flow occurs naturally. However, patterning the hydrophobic material in a portion of the hydrophilic channel, as shown in FIG. 1, lowers the pressure in the fluid. At this time, depending on the ratio of the hydrophobic material occupies the circumference of the channel, the pressure in the fluid may be close to zero, if the hydrophobic material occupies more than a certain ratio, the pressure in the fluid becomes negative (-) to stop the flow . Thus, by controlling the proportion of the pattern of hydrophobic material in the hydrophilic channel, the pressure in the fluid can be controlled, and inducing a pressure close to zero but greater than zero can reduce the speed of the overall flow.

FIG. 2 is a graph showing the pressure change in the capillary flow when the fluid moves in the manufactured microchannel as shown in FIG. 1. As shown in FIG. 2, the fluid moving through the hydrophilic channel has a positive pressure, but when it encounters a pattern of hydrophobic material, the pressure in the fluid decreases to near zero. However, since the pressure in the fluid is still positive, the velocity of the flow decreases significantly but does not stop.If it passes through the pattern of hydrophobic material after a certain time, it recovers to the previous pressure and the velocity of the flow also moves before the pattern of hydrophobic material. Return to

This phenomenon can be explained by the change of energy at the liquid-gas-solid interface. The interfacial energy of the system can be expressed as Equation 1 below.

In Equation 1, A _sl , A _sa , and A _la are the area of a solid-liquid, solid-gas, and liquid-gas interface, and γ _sl , γ _sa , γ _la represent surface energy per unit area corresponding thereto.

When the channel surface is made of various kinds of materials, the equation (1) is modified to the following equation (2).

In Equation 2, S _i means the i-th solid surface. When the equilibrium contact angle of the liquid at the i-th solid surface is θ _si , the following equation (3) can be obtained by Young's formula.

Therefore, the pressure in the fluid is as follows.

In Equation 4, V _| represents the volume of the introduced fluid.

Equation 4 expressed using Equations 1 to 3 represents an internal pressure of capillary flow in a microchannel composed of various kinds of materials. According to Equation 4, when a particular portion of the surface of the i-th channel is made of a hydrophobic material, cosθ _si becomes negative, thereby reducing the pressure in the flow. Thus, if the hydrophobic material is properly patterned on the channel surface, capillary flow can be controlled.

The capillary flow delay method as described above may be used to secure reaction time in chemical and biological reactions. For example, in a microfluidics system such as Lab-on-a-Chip, when inducing an antigen-antibody reaction or an enzyme reaction, a constant reaction time is required to increase the reaction efficiency. It can be used to secure.

3 illustrates a cross-sectional shape of various types of microchannels implemented by the present invention. 3 (a) and 3 (b) form a microchannel by bonding a flat substrate 11 to a substrate 12 on which a channel is formed. In the above case, as shown in FIG. 3A, the hydrophobic pattern 30 may be inserted into the flat substrate 11, and as shown in FIG. 3B, the hydrophobic pattern 30 is inserted into the microchannel. Hydrophobic patterns can be inserted both on the flat substrate and inside the microchannel.

On the other hand, Figure 3 (c) is a microchannel formed by separating the wall surface 15 of the microchannel from the upper 14, the lower substrate 13, and then laminated, in this case, the upper and lower substrates Optionally, the hydrophobic pattern 30 can be inserted.

3 (d) is a case where there is no wall of the microchannel, unlike FIGS. 3 (a), (b) and (c), and the channel form is formed on one or both of the upper 17 and the lower 16 substrates. By inserting the hydrophobic pattern 30 of the fluid so that the fluid flows only on the hydrophilic surface, in this case, the channel-type hydrophobic pattern serves as a virtual wall. 3 (d) illustrates a case in which a microchannel is formed by inserting the hydrophobic pattern 30 into the hydrophilic substrate 16 and then covering the hydrophobic substrate 17. FIG. This is a case where a hydrophobic pattern 30 having a channel shape is manufactured on the substrate 18, and a hydrophobic pattern 30 for delaying flow is inserted into only one substrate. In addition, FIG. 3 (f) illustrates a case in which channel-type hydrophobic patterns and hydrophobic patterns for flow retardation are inserted into both the upper and lower substrates 18. As shown in FIG. 3, the capillary flow delay device of the present invention may be variously modified according to the desired delay time and application method.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention, it will be apparent to those skilled in the art that the scope of the present invention is not to be construed as being limited by these examples.

Example 1 Observation of Capillary Flow Delay According to Shape of Hydrophobic Pattern

The delay time of the capillary flow was observed according to the shape of the hydrophobic pattern. 4 shows the hydrophobic pattern 210 for retardation of capillary flow. Delay in capillary flow when the width of the entire channel 230 is w ₀ , the spacing between the hydrophobic pattern and the hydrophobic pattern is w ₁ , the number of hydrophilic patterns between the hydrophobic patterns is n, and the channel direction length of the hydrophobic pattern is L. The time is inversely proportional to (w ₁ × n) / w ₀ . That is, the delay time of the capillary flow increases in proportion to the ratio of the hydrophobic pattern to the total channel width. In this example, after w ₀ was fixed at 1 mm and n was 5, the delay time of capillary flow was observed according to w ₁ and L.

5 is a schematic diagram of a microfluidic device 100 patterned with a hydrophobic material for retardation of capillary flow. The hydrophobic material 150 was patterned on the hydrophilic substrate 110 as shown in FIG. 3, and the substrate 120 having relatively hydrophobicity was bonded to the upper surface of the microchannel compared to the lower substrate. At this time, by using a spacer 140 made of an adhesive to secure a space between the upper and lower substrates to control the depth of the micro channel. The microchannel of the present invention creates a virtual wall surface by the hydrophobic pattern 150, so that the fluid injected at the inlet 130 can move along a path defined by the surface tension by the hydrophilic surface.

6 illustrates a method of patterning hydrophobic material. Polydimethylsoloxane (PDMS) 210 dissolved in chloroform was poured onto the glass substrate 200, spin-coated at 4500 rpm for 30 seconds, and then the PDMS stamp 220 having an embossed pattern was formed on the coated glass substrate. PDMS dissolved in chloroform was transcribed. After the stamp was bonded onto the glass substrate 230, the stamp 220 was removed and cured at 70 ° C. for about 10 minutes to complete the pattern 210 of hydrophobic material. The PMMA substrate was bonded to the completed substrate using a 50 μm thick spacer (3M adhesive) as shown in FIG. 5.

10 μl of distilled water was dropped into the inlet 130 of the microfluidic device manufactured as described in FIG. 5 to measure the delay time in the hydrophobic pattern 160. 7 is a graph showing the measured delay time. The horizontal axis of the graph represents the ratio of the hydrophobic pattern to the total channel width, and the vertical axis represents the delay time due to the hydrophobic pattern. As can be seen from the graph, the delay time of the capillary flow increases as w ₁ decreases, that is, as the proportion of the hydrophobic pattern in the total channel width increases, and as the channel length of the hydrophobic pattern increases, It can be seen that the delay time increases. Therefore, it was confirmed that the repetitive patterning of the hydrophobic material presented by the present invention can control the delay time of the natural capillary flow.

8 is a view showing capillary flow when w ₁ is 75 μm and L is 500 μm, and a dotted line shows a channel formed by a hydrophobic pattern. As shown in FIG. 7 (a), the fluid rapidly flows when it meets the hydrophobic pattern as shown in FIG. 7 (b). As described above, when a predetermined time elapses according to the shape of the hydrophobic pattern, the capillary flow reaches the end of the hydrophobic pattern as shown in FIG. 7 (c) and resumes the flow as shown in FIG. 7 (a). Figure 7 (d) is a view of the microfluidic device of the present embodiment filled with fluid by capillary flow.

Example 2: Preparation of Capillary Flow Delay Devices with Hydrophobic Pattern

A microchannel including a hydrophobic pattern was manufactured in the same manner as in FIG. 3 (a). The hydrophobic material was patterned on the flat PMMA substrate using the same method as in Example 1. In this case, as the hydrophobic material, PDMS was dissolved in toluene, and a mass ratio of PDMS and toluene was 1:25. Figure 9 shows the state of the microfluidic device of the present invention, after patterning the liquid PDMS on the PMMA substrate using a PDMS stamp embossed, such as a gray pattern 310 is virtually displayed, at about 10 ℃ 70 Cured for minutes. 10 is an optical microscope to observe the hydrophobic pattern of the microfluidic device according to the present invention. As shown in FIG. 10, the hydrophobic material 310 patterned on the hydrophilic substrate 330 could be clearly distinguished. The microchannel formed PMMA was produced by injection molding using a metal mold made by the UV-LIGA method, and the PMMA substrate including the hydrophobic pattern and the PMMA substrate formed with the microchannel were bonded using a UV adhesive.

In the above method, when 10 μl of distilled water was dropped at the inlet of the manufactured microfluidic device, it was found that capillary flow occurred due to the surface tension as shown in FIG. As a result, the time that the fluid moves from Fig. 11 (a) to Fig. 11 (b) is about 1.5 seconds, while the time the fluid moves from Fig. 11 (b) to Fig. 11 (c) is about 4.5 seconds. Therefore, it was confirmed that the flow was further delayed by the hydrophobic pattern while traveling two similar distances.

As described above in detail a specific part of the content of the present invention, for those of ordinary skill in the art, such a specific description is only a preferred embodiment, which is not limited by the scope of the present invention Will be obvious. Therefore, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

As described in detail above, according to the present invention, a capillary flow retardation device, characterized in that it is possible to control the delay time of capillary flow by adjusting the pattern shape and the ratio of materials having different affinity with water in a part of the microchannel ( device) and a capillary flow delay device, and a microfluidic device manufactured using the same.

According to the capillary flow delay device of the present invention, it is possible to adjust the delay time of the capillary flow, it can be applied to ensure the reaction time required in chemical and biological reactions.

Claims (19)

A capillary flow retardation device characterized in that the hydrophobic material is repeatedly patterned so that the hydrophilic surface and the hydrophobic surface are alternately arranged at the center of the microchannel of the hydrophilic material. 2. The capillary flow retardation device of claim 1, wherein the hydrophilic microchannel is glass or polymethylmethacrylate (PMMA). The device of claim 1, wherein the hydrophobic material is polydimethylsiloxane (PDMS). 2. The capillary flow retardation device of claim 1, wherein hydrophobic material is additionally patterned on the periphery of the microchannel to form a virtual wall. A capillary flow retardation device characterized in that the hydrophilic material is repeatedly patterned so that the hydrophilic surface and the hydrophobic surface are alternately arranged at the center of the microchannel of the hydrophobic material. 6. The capillary flow retardation device of claim 5, wherein a hydrophilic material is additionally patterned on the periphery of the microchannel to form a virtual wall surface. 6. The capillary flow retardation device of claim 1 or 5, wherein the patterning shape is arranged in the flow direction of the fluid. 6. The capillary flow retardation device of claim 1 or 5, wherein the patterning shape is arranged in a direction perpendicular to the flow of the fluid. 6. The capillary flow retardation device of claim 1 or 5, wherein the microchannel material is selected from the group consisting of polymer, glass, quartz, silicon, metal, ceramic, porous membrane, and the like. A method for delaying capillary flow, comprising using the capillary flow delay device of claim 1. And repeating patterning the hydrophobic material such that the hydrophilic surface and the hydrophobic surface are alternately arranged at the center of the microchannel of the hydrophilic material. 12. The method of claim 11, wherein the patterning ratio of the hydrophobic material is varied to vary the capillary flow delay time. The method according to claim 11 or 12, wherein the method for patterning the hydrophobic material is selected from the group consisting of a light deposition method, a plasma deposition method, an ink transfer method using a printer, and a micro contact printing method. And repeating patterning the hydrophilic material such that the hydrophilic surface and the hydrophobic surface are alternately arranged at the center of the microchannel of the hydrophobic material. 15. The method of claim 14, wherein the patterning ratio of the hydrophilic material is varied to vary the capillary flow delay time. 16. The method of claim 14 or 15, wherein the method of patterning the hydrophilic material is selected from the group consisting of a light deposition method, a plasma deposition method, a transfer method of ink using a printing press, and a micro contact printing method. The capillary flow retardation device of any one of claims 1 to 4 is attached with a hydrophilic or hydrophobic cover substrate, and a spacer for controlling the depth of the microchannel between the capillary flow retardation device and the hydrophilic or hydrophobic cover substrate is mounted. Microfluidic elements. A microfluidic device having a hydrophilic or hydrophobic cover substrate attached to the capillary flow delay device of claim 5 or 6, and a spacer for controlling the depth of the microchannel between the capillary flow delay device and the hydrophilic or hydrophobic cover substrate. . 19. The microfluidic device of claim 18, wherein the hydrophilic cover substrate is made of at least one selected from the group consisting of polymer, glass, quartz, silicon, metal, ceramic, porous membrane, and the like.

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