KR100806568B1 - Microfluidic Device and Apparatus for Diagnosing and Analyzing Having the Same - Google Patents

Abstract

The present invention relates to a microfluidic device and a diagnostic and analysis device having the same, wherein the microfluidic device according to the present invention is a microfluidic device having a microchannel through which a microfluid flows, wherein the microfluidic device has a first flow through which the microfluid flows. An inlet having a cross section; A microfluidic discharged from the inlet, and having a predetermined length extending from the first end face to a second end face having an area larger than that of the first end face; And a flow accelerator having a cross section substantially the same as the second cross section. Thereby, through the shape design of the flow path in the natural flow by capillary force, not only does it need to increase the flow rate at a specific point in time for the washing effect for the selectivity of the reaction without additional manipulation and energy, but it is also easy to manufacture. Simple to use.

Microfluidics, microchannels, capillary flow, diagnostic devices, analytical devices

Description

Microfluidic Device and Apparatus for Diagnosing and Analyzing Having the Same}

1 is a schematic diagram of a typical microchannel;

2 is a graph showing the change over time of the pressure distribution of the capillary flow,

3A is a schematic representation of a flow acceleration model,

FIG. 3b is a schematic diagram of a flow acceleration model in which an inner wall is inserted into an area where an interface is located in FIG. 3a;

Figure 4a is a graph showing the change over time of the pressure distribution in the case of expanding the flow passage cross-sectional area,

Figure 4b is a graph showing the change in speed for each section in the case of flow passage cross-sectional area enlargement,

Figure 4c is a graph showing the results of the change over time of the D ₁ zone velocity for the case where the wall is inserted into the flow acceleration model to increase the size of the interfacial pressure,

4d is a graph showing the effect of the number of internal walls inserted on the velocity;

5A is a schematic diagram of a microfluidic device of the flow acceleration model according to the first embodiment of the present invention;

5b to 5c are schematic views of a flow acceleration model according to the second and third embodiments of the present invention, including structures of various shapes for increasing capillary force;

Figure 6 is a schematic diagram of a diagnostic and analysis device according to an embodiment of the present invention applying the flow acceleration model according to the present invention.

* Explanation of symbols for main parts of the drawings

      1: Diagnostic and analysis device with microfluidic device

     20 microfluidic element 21 inlet

     22: cross-sectional expansion portion 23: flow acceleration portion

     24: acceleration wall 25: tip of acceleration wall

     26: acceleration passage 101: sample introduction portion

    102 reaction unit 103 detection unit

104, 105: flow delay model 110: flow acceleration model

The present invention relates to a microfluidic device and a diagnostic and analysis device having the same, and more particularly, to a microfluidic device capable of quantitatively controlling the flow of a very small amount of fluid in a natural capillary flow by capillary force. (microfluidic device) and a diagnostic and analysis device having the same.

The microfluidic technology of flow generation and control, which transfers and controls very small amounts of fluid, is a key element that enables the operation of diagnostic and analytical devices, which can be implemented with various driving principles. Among them, a pressure-driven method for applying pressure to the fluid injection portion, an electrophoretic method for transferring fluid by applying a voltage between the microchannels, an electroosmotic method, and a capillary force The capillary flow method used is representative.

A representative example of a microfluidic device of a pressure-driven microfluidic device by artificial pressure is U.S. Patent No. 6,296,020. U.S. Patent No. 6,296,020 uses a manual valve such as control of a cross-sectional area of a hydrophobic fluid element and hydrophobic control of a flow path. A fluid circuit element is disclosed. In addition, U.S. Patent No. 6,637,463 discloses a microfluidic device for uniformly distributing fluid into a plurality of flow paths by designing a flow path having a pressure gradient.

On the other hand, the capillary flow method takes advantage of the capillary phenomenon that occurs naturally in the micro-channel, so that an extremely small amount of fluid placed in the fluid injection portion without additional device moves naturally and immediately along a given channel, which is currently utilized. There is an active research on the design of a microfluidic system. U.S. Patent No. 6,271,040 discloses a diagnostic biochip that detects a specific substance in a sample by an optical method by transferring the sample using a natural capillary flow in a microchannel without using a porous material and causing a reaction of the sample. It is starting. In addition, US Patent No. 6,113,855 discloses a device for generating capillary force by properly arranging hexagonal pillars for the transfer of samples between two points away from the diagnostic device.

However, in the conventional microfluidic device and the diagnostic and analysis device having the same, the flow rate is increased only at a specific time point for the washing effect for the selectiveness of the reaction while minimizing the overall time required in the diagnostic and analysis device. Although the design of the flow path in the form of a key is important, there is a problem that there is little research on such technology. In consideration of these problems, a method of changing the equilibrium contact angle by partially changing the interfacial tension or partially changing the surface energy of the capillary wall may be considered, but such a method requires a further device or additional work.

Therefore, the object of the present invention is to solve this problem of the prior art, only through a specific design for the cleaning effect for the selective selectivity of the reaction without the need for additional manipulation and energy through the shape design of the flow path in the natural flow by capillary force It is to provide a microfluidic device capable of increasing the flow rate as well as being easy to manufacture and simple to use, and a diagnostic and analysis device having the same.

The object is, according to the present invention, in the microfluidic device having a microchannel through which the microfluid flows, an inlet having a first cross section through which the microfluid flows; A microfluidic discharged from the inlet, and having a predetermined length extending from the first end face to a second end face having an area larger than that of the first end face; And a flow accelerator having a cross section substantially the same as the second cross section.

Here, the flow acceleration unit, it is preferable to have at least one acceleration wall arranged in the longitudinal direction at a predetermined interval horizontally in the longitudinal direction in which the microfluid flows to form a plurality of flow paths therein.

In addition, it is preferable that the end portion of the cross-sectional extension part side of the acceleration wall is pointed so that the fine liquid flowing into the flow acceleration part from the cross-sectional extension part flows separately into the plurality of flow paths.

And, the acceleration wall may be a thin plate formed in the longitudinal direction of the flow acceleration portion.

In addition, the surface of the flow path of the flow acceleration portion is preferably hydrophilic treatment.

The inlet may be a flow path connected to a detection unit in which the microfluid reacts with the immobilized antibody present therein.

In addition, according to the present invention, there is provided a diagnostic and analysis device having the aforementioned microfluidic device.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention effectively increases the velocity of a fluid flowing through a capillary effect in a specific region. First, a flow acceleration module for arranging model equations for pressure difference and contact angle at the interface, which is the root cause of capillary flow, and for accelerating the flow using the capillary effect The design principle of the circuit will be described.                     

Capillary flow generation is due to a discontinuous change in pressure occurring at the gas-liquid interface and is manifested when the interface is curved and curved. The cause of the interfacial curvature is the contact angle (θ) between the interface and the wall at the triple point where the gas-liquid interface and the solid wall meet. In general, the contact angle is defined as the angle toward the liquid at the interface between the wall and the surface, where 0 <θ <π / 2 if the wall is more intimate with the liquid than gas, and vice versa π / 2 <θ <π. Neglecting the edge effect of the tube in the case where the cross section of the fluid flow path is rectangular, the pressure change excluding the flow effect can be expressed as follows.

------ (수학식 1)

------ (Equation 1)

FIG. 1 is a schematic diagram of a general microchannel, as shown here, where the general microchannel is manufactured to have a depth and width of several tens to hundreds of micrometers (μm). In Equation 1, depth is represented by b and width is represented by c. In most cases, it is manufactured under the condition of b <c. Therefore, b may be referred to as primary length and c as secondary length according to the contribution to ΔP generation. The pressure change occurring at the interface is connected to the position (a) of the interface to generate a pressure gradient of ΔP / a, which produces the motion of the fluid. The generated flow is included in the laminar flow region, and the resistive terms (?) And the flow rate (v) due to the pressure gradient term and the flow path wall surface have the following relationship.

---------- (수학식 2)

---------- (Equation 2)

In the case of a rectangular flow passage cross section, the resistive term is given as follows for the primary length (b) and the secondary length (c) of FIG.                     

------- (수학식 3)

------- (Equation 3)

Assuming a pseudo steady state, the following ordinary differential equation for the interface position can be obtained.

--------- (수학식 4)

--------- (Equation 4)

As shown in FIG. 1, if the flow passage cross section is rectangular and constant, a theoretical solution regarding the interface position, flow velocity, and pressure distribution can be obtained. In FIG. 2, the time-dependent change in the pressure distribution of the capillary flow is shown when 2b = 50 μm, 2c = 200 μm, Υ = 0.07 N / m, and θ = π / 3. In FIG. 2, a negative pressure gradient is a liquid phase region, a pressure free interval is a gas phase region, and a sudden change in slope corresponds to a position of an interface. The flow generated by the amount of pressure change in the liquid phase region shifts the position of the interface, and as the position of the interface moves, the slope of the pressure change gradually decreases, and thus the speed of the interface movement decreases with time.

The present invention provides a flow acceleration model that increases the flow rate of capillary flow in a particular region. As can be seen from Equation 2, the capillary flow velocity increases at the position (a) of the interface as the flow proceeds. Therefore, when ΔP is fixed, the moving speed of the interface decreases with time, and the only way to accelerate it again is to increase ΔP as a increases, but the implementation thereof is very limited. However, when it is necessary to accelerate the speed of a specific position inside the flow path rather than the moving speed of the interface in the flow path design of the diagnostic apparatus, the flow acceleration model developed in the present invention has a powerful effect. The flow relation formula utilized in the present invention is the following mass conservation formula for the case where two flow paths having different fluid passage cross sections are connected.

-------------- (수학식 5)

-------------- (Equation 5)

In Equation 5, V ₁ is the velocity of the region D ₁ to be accelerated and V ₂ corresponds to the flow velocity of the region D _{2 at} which the interface is located. In Equation 5, it can be seen that the method of increasing V _{1 is} to increase V ₂ or increase the ratio of the capillary primary length (b ₂ / b ₁ ) or the ratio of the secondary length (c ₂ / c ₁ ). have. At this time, since V ₂ is a variable controlled by Equation 2, it is very limited to increase it, but the ratio of the capillary primary or secondary lengths can be changed relatively freely. A feature of the design of the flow acceleration model of the present invention is the intensive use of the effect of b ₂ / b ₁ or c ₂ / c ₁ on V ₁ .

3A is a schematic diagram of a flow acceleration model when the capillary primary length is kept constant and the ratio of the secondary lengths is increased. The reason for keeping the capillary primary length constant is to minimize the flow retardation effect experienced by the interface at the moment the position of the interface moves to the secondary length increasing region. It should be noted that the capillary pressure at the interface decreases due to an increase in c ₂ / c ₁ , which causes a flow rate reducing effect. In the present invention, as a countermeasure, a flow acceleration model in which an inner wall is inserted into a region where an interface is located is illustrated and illustrated in FIG. 3B. At this time, the increase in the number of the inner wall inserted in Figure 3b increases the flow rate by the effect of increasing ΔP, but the inner wall inserted in any number of more increases the wall resistance force to reduce the flow rate. In other words, there is an optimal number of walls to maximize V ₁ for the thickness of the inner wall to be inserted. In this case, using Equation 5 can theoretically predict the optimal number of walls according to the thickness of the wall to be inserted.

In FIG. 4A, the change over time of the pressure distribution when a ₁ = 2000 μm, 2b ₁ = 50 μm, 2c ₁ = 200 μm, 2b ₂ = 50 μm, 2c ₂ = 2000 μm, Υ = 0.07 N / m, θ = π / 3 Indicated. That is, it corresponds to a condition in which the calculation condition of FIG. 2 for the simple straight flow path is maintained up to a ₁ = 2000 μm and the length is increased ten times in the capillary secondary length direction. In FIG. 4A, the pressure rapidly changes in a region D ₁ having a small fluid passage cross-sectional area, and changes with a gentle slope in the region D ₂ having a large cross-sectional area. The ratio of the slope of the pressure change in the two regions D ₁ and D ₂ is inversely proportional to the ratio of the cross-sectional area of the fluid passage and the ratio of the resistive term. The calculation condition of FIG. 4A corresponds to a case where the change in the resistive term is relatively small, so that the ratio of the gradient of the pressure change is given by approximately 10: 1. Since the velocity ratio of the two regions is inversely proportional to the area ratio, the velocity of the region D ₁ having a small cross-sectional area is maintained at ten times the velocity of the region D ₂ having a large cross-sectional area. Compared with the results of FIG. 2, the size of the interfacial pressure was reduced due to the expansion of the fluid passage cross-sectional area under the conditions of FIG. 4a, and the slope of the pressure change was smoothed at D ₂ , but the slope of the pressure change was rapidly increased at D ₁ . Can be.

4B is a result of time-dependent change in velocity for each region. The dotted line in the figure is the calculation result for the condition of FIG. 2 with no change in the cross-sectional area of the fluid passage, and the solid line is the result for the condition of FIG. 4A with a 10 times larger cross-sectional area. Therefore, the cross-sectional area enlargement reduces the moving speed (V ₂₎ of the surface speed (V ₁₎ of the D ₁ can know the clearance made relative to the effect of maintaining a large value. In other words, the flow passage cross-sectional enlargement effect in the capillary flow can be said to suppress the decrease of the small cross-sectional area velocity.

Figure 4c is a graph showing the results of the change over time of the D ₁ zone speed for the case where the wall is inserted into the flow acceleration model to increase the size of the interfacial pressure. Calculation conditions are the same as in the case of FIG. 4A, and n inner wall surfaces having a thickness of 10 μm are inserted in the region D ₂ . In FIG. 4C, it can be seen that the insertion of the inner wall increases the magnitude of the interface generating pressure and increases the speed V ₁ of the D ₁ region. In the case of excessive insertion of the inner wall, the resistance of the wall increases and thus the capillary flow rate decreases. As can be seen in FIG. 8C, the insertion of 20 inner walls increases the speed of all time intervals, while the 40 insertions of the inner walls increase the initial velocity at which the interface enters the flow acceleration model, but the speed is increased due to the increase of internal wall resistance. Suddenly decreasing again, the velocity at t = 1 [s] is smaller than without the inner wall.

In the present invention, using the mathematical model used, the optimum value of the number of interior walls to be inserted under a given condition can be calculated, and the results are shown in FIG. 4D. The calculation condition used is the same as that of FIG. 4C and corresponds to the result of t = 1 [s]. In FIG. 4D, there is an optimal number of walls to maximize V ₁ for each inner wall thickness, and as the thickness of the inserted wall is thinner, the effect of increasing the velocity increases. From the theoretical analysis results of the present invention, it can be seen that the insertion of the inner wall having the thinnest thickness possible is the most effective in accelerating the flow because it increases the amount of interfacial pressure and minimizes the internal resistance. However, since the production of a thin wall is limited according to the fabrication method, the present invention designed a flow acceleration model in consideration of the ease of fabrication of the actual microchannel.

Figure 5a is a schematic diagram of a microfluidic device of the flow acceleration model according to the first embodiment of the present invention, as shown in the microfluidic device 10 of the flow acceleration module according to the present invention, the An inlet portion 11 having a first cross section and a microfluid discharged from the inlet portion 11 flow in and gradually extend from the first cross section to a second cross section having an area larger than that of the first cross section. At least one having a cross-sectional extension 12 and a cross-section substantially the same as the second cross-section and are arranged along the longitudinal direction at predetermined intervals in a horizontal direction in the longitudinal direction in which the microfluid flows, thereby forming a plurality of flow paths therein. It has a flow acceleration portion 13 having an acceleration wall (14) of.

Here, the front end portion 15 of the cross-sectional extension portion 12 side of the acceleration wall 14 has a pointed shape so that the fine liquid of the cross-sectional extension portion 12 is separated into a plurality of flow paths, and the acceleration for increasing the capillary force is increased. The wall 14 is a thin plate formed long in the longitudinal direction of the flow acceleration part 13. In addition, the acceleration accelerator 13 forms the at least two acceleration passages 16 by the acceleration walls 14. On the other hand, the surface of the flow path of the flow acceleration part 13 can be hydrophilic.

In such a configuration, the capillary flow supplied to the inlet 11 is transferred to the plurality of acceleration passages 16 through the cross-sectional extension 12. One acceleration flow path has a large capillary force because of its small cross-sectional area, and by arranging a plurality of acceleration flow paths, the cross-sectional area through which the entire flow moves increases and capillary force increases. Therefore, the flow transferred from the cross-sectional extension 12 to the acceleration passage 16 increases the flow rate compared to the case without the acceleration passage 16, which significantly increases the flow velocity of the inlet portion (11).

 On the other hand, the thinner the thickness of the acceleration wall 14 inserted in order to minimize the resistance to capillary flow is better, the tip portion 15 of the wall at the point where the cross-sectional extension 12 and the acceleration flow path 16 is connected Maintaining a pointed triangular shape is effective. In addition, the point where the inlet portion 11 and the cross-sectional extension portion 12 are connected, and the point where the cross-sectional extension portion 12 and the acceleration passage 16 are connected to each other are manufactured in a curved line so as not to give resistance to the capillary flow.

5B and 5C are schematic diagrams of a flow acceleration model according to the second and third embodiments of the present invention including structures of various shapes to increase capillary force. The components corresponding to the first embodiment of FIG. 5A are indicated by adding 'a' and 'b', respectively, as shown in these figures, in place of the acceleration wall 14 of FIG. Increase the capillary force of the flow acceleration model by inserting the various structures of. In this case, the structure may be manufactured by selecting a suitable height from the bottom surface of the flow path to the top or a height between the top surface and the bottom surface of the flow path.

Figure 6 is a schematic diagram of a diagnostic and analysis device according to an embodiment of the present invention applying the flow acceleration model according to the present invention, the diagnostic and analysis device 1 according to an embodiment of the present invention to be diagnosed from the outside The sample introduction part 101 to which a sample is supplied, the reaction part 102, the flow delay models 104 and 105, the detection part 103, and the flow acceleration model 110 are provided. Here, the flow retardation model uses a method of reducing ΔP. The flow retardation model retards the flow in a specific region by effectively adjusting the interface curvature by bending the wall with respect to the primary length or the secondary length.

The reaction unit 102 includes a combination of a detection antibody and a fluorescent dye in advance, and the detection unit 103 is fixed to the surface in advance. The sample supplied through the sample introduction unit of the diagnostic and analysis device 1 is transferred to the reaction unit 102 through the microchannel. In the reaction unit 102, an antigen in a sample reacts with a combination of a detection antibody and a fluorophore to form an antigen-antibody-fluorescence chromophore conjugate. At this time, the flow delay models 104 and 105 are introduced to secure the reaction time, and the reaction time in the reaction unit 102 may be adjusted according to the design of the flow delay models 104 and 105. Since the detection antibody-fluorescence chromophore conjugate previously included in the reaction unit 102 is not fixed to this device, the antigen-antibody-fluorescence chromophore conjugate in the reaction unit 102 is transferred to the detection unit 103 through the microchannel. . The immobilized antibody is immobilized on the surface of the detector 103 so that the antigen-antibody-fluorescent chromophore conjugate reacts with the immobilized antibody of the detector 103 and is immobilized to the detector 103. At this time, the reaction time of the detector 103 is adjusted using the flow delay models 104 and 015. After the reaction in the detector 103 is completed, the sample moves to the flow acceleration model 110. The flow rate of the sample in the microchannel before the flow acceleration model 110 is increased by the action of the flow acceleration model 110, through which the unnecessary substance or non-specifically bound antigen-antibody-fluorescence present in the detector 103 is increased. The chromophore conjugate is removed.

The micro-channel manufactured in the present invention is formed by covering the plate including the pattern of the intaglio flat or embossed or the plate containing the intaglio. The plate may be made of various materials such as polymer, metal, silicon, glass, printed circuit board (PCB), and preferably includes a polymer material. For example, PMMA (polymethylmethacrylate), PC (polycarbonate), COC (cycloolefin copolymer), PDMS (polydimethylsiloxane), PA (polyamide), PE (polyethylene), PP (polypropylene), PPE (polyphenylene ether), PS (polystyrene), It refers to plastics such as polyoxymethylene (POM), polyetherketone (PEEK), polytetrafluoroethylene (PTFE), polyvinylchloride (PVC), polyvinylidene fluoride (PVDF), polybutyleneterephthalate (PBT), and fluorinated ethylenepropylene (FEP). Such materials are widely used in mold molding such as injection molding, hot embossing or casting. In particular, such materials are generally inert and are preferred for the gastric flow path due to their ease of manufacture, low cost and one-off.                     

According to the present invention, a method for manufacturing a micro-channel includes manufacturing a mold plate formed with an embossed shape corresponding to the micro-channel, and imitating a negative plate on the template, and then adjusting the hydrophilicity of the surface of each plate and the second plate. And, the negative plate is bonded to the second plate.

In the above-described embodiments, the acceleration wall is provided in the flow acceleration section, but the acceleration wall is not installed in the flow acceleration section if the flow velocity of the inflow section can be sufficiently increased by extending the cross-sectional area of the flow acceleration section than the inflow section. Of course it can.

 In addition, in the above-described embodiments, the cross-sectional shape of the microfluidic device has been described above as a quadrangular shape. However, the cross-sectional shape of the microfluidic device may be various shapes such as a circular shape.

As described above, according to the present invention, through the shape design of the flow path in the natural flow by the capillary force, it is possible to increase the flow rate only at a certain time point for the washing effect for the selectivity of the reaction without the need for additional manipulation and energy. In addition, there is also provided a microfluidic device that is easy to manufacture and simple to use, and a diagnostic and analysis device having the same.

Claims (7)

A microfluidic device having a microchannel through which microfluids flow, an inlet having a first cross section through which the microfluid flows; A microscopic fluid flowing in from the inlet, and having a predetermined length extending from the first cross-section to a second cross-section having an area larger than that of the first cross-section; And It has the same cross section as the second cross section so as to accelerate the flow rate at the inlet by capillary flow, and is aligned along the length direction at a predetermined interval in the horizontal direction in which the microfluid flows therein. A flow acceleration part having at least one acceleration wall forming a plurality of flow paths in the flow path; Microfluidic device comprising a. delete The microfluidic device of claim 1, wherein the end surface of the accelerated wall has a pointed end portion such that the microfluidic liquid flowing from the cross-sectional extension part to the flow acceleration part is separated into the plurality of flow paths. The microfluidic device of claim 1, wherein the acceleration wall is a thin plate formed to extend in the longitudinal direction of the flow acceleration part. The method of claim 1, The surface of the flow path of the flow acceleration portion is a microfluidic device, characterized in that the hydrophilic treatment. In claim 1, The inlet is a microfluidic device, characterized in that the flow path is connected to the detection unit for the microfluid reacts with the immobilized antibody present therein. A diagnostic and analysis device comprising the microfluidic device according to any one of claims 1 and 3 to 6.

Images