Microfluidic device

Abstract

The present invention relates to a microfluidic device capable of rapidly separating high-flow particles by using a simple method of flowing fluid without using external forces such as electric force, magnetic force, or acoustic waves, unlike conventional microfluidic devices.

Description

Technology Field

[0001] The present invention relates to a microfluidic device capable of separating particles in a fluid according to their size. Background Technology

[0003] Microparticles in the blood consist of red blood cells, white blood cells, bacteria, and cancer cells.

[0004] Among them, red blood cells are an essential component of blood transfusions that enables life to be sustained. On the other hand, white blood cells, bacteria, and cancer cells can cause immune system abnormalities or rejection reactions in the recipient during transfusion, leading to serious side effects.

[0005] Accordingly, there have been various attempts to utilize microfluidic devices to separate only red blood cells from blood. However, conventional microfluidic devices separate microparticles using external forces such as electric force, magnetic force, and acoustic force, which results in complex product design; furthermore, they are unsuitable for blood transfusions as they can only process blood under low flow rate conditions.

[0006] Considering the above points, there is currently a need for the development of microfluidic devices capable of processing high-flow blood without using external forces. The problem to be solved

[0008] The present invention aims to selectively separate particles in a fluid according to size through the structure of a channel without using external force.

[0009] The objects of the present invention are not limited to those mentioned above, and other unmentioned objects and advantages of the present invention may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. means of solving the problem

[0011] A microfluidic device according to one embodiment of the present invention includes a first channel extending in the longitudinal direction and a second channel extending parallel to the first channel above the first channel and communicating vertically with the first channel, wherein the width of the second channel gradually narrows along the direction of fluid flow. Effects of the invention

[0013] Unlike conventional microfluidic devices, the present invention can separate particles according to size in a simple manner by flowing fluid without using external forces such as electric force, magnetic force, and acoustic waves, thereby enabling rapid separation of high flow rates. Accordingly, it has the advantage of being applicable in various fields such as rapid diagnosis using blood, fluid purification, microplastic removal, and blood transfusion.

[0014] In addition to the effects described above, the specific effects of the present invention are described together with the specific details for implementing the invention below. Brief explanation of the drawing

[0016] FIG. 1 is a perspective view of a microfluidic device according to one embodiment of the present invention. Figure 2 is a cross-sectional view of a microfluidic device. FIG. 3 is a cross-sectional view AA' illustrating fluid velocity and microparticle movement. Fig. 4 is a cross-sectional view of BB' illustrating fluid velocity and microparticle movement. Fig. 5 is a cross-sectional view of CC' illustrating fluid velocity and microparticle movement. Figure 6 is a diagram illustrating the movement of the fluid in the CC' cross-section. FIG. 7 is a perspective view of a microfluidic device according to another embodiment. Specific details for implementing the invention

[0017] The aforementioned objectives, features, and advantages are described in detail below with reference to the attached drawings, thereby enabling those skilled in the art to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions would unnecessarily obscure the essence of the invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0018] In this specification, terms such as "first," "second," etc. are used to describe various components, but these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may be the second component.

[0019] Additionally, in this specification, the statement that any configuration is disposed on the "upper (or lower)" or "upper (or lower)" of a component may mean not only that any configuration is disposed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration disposed on (or below) said component.

[0020] Furthermore, where it is stated in this specification that one component is "connected," "coupled," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "coupled," or "connected" through another component.

[0021] Additionally, singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may not be included, or that additional components or steps may be included.

[0022] Additionally, in this specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less unless specifically stated otherwise.

[0024] The present invention relates to a microfluidic device capable of separating particles in a fluid according to their size. Hereinafter, the microfluidic device of the present invention will be described in detail with reference to the drawings.

[0025] First, we will explain the structure of the microfluidic device in detail, and then explain the fluid flow generated by that structure.

[0026] Referring to FIG. 1, the microfluidic element (1) may include first and second channels (100, 200), an inlet (10) and a plurality of outlets (20) formed on one side and the other side of the first and second channels (100, 200), respectively.

[0027] However, the microfluidic element (1) shown in FIG. 1 is according to one embodiment, and the structure of the invention is not limited to the embodiment shown in FIG. 1, and some components may be added, changed, or deleted as needed.

[0028] The first channel (100) may be extended in the longitudinal direction, that is, in the z-axis direction. The second channel (200) may be extended parallel to the first channel (100) on the upper side of the first channel (100).

[0029] At this time, referring to FIG. 2, one side wall of the first channel (100) can be aligned in a straight line with one side wall of the second channel (200).

[0030] The first channel (100) and the second channel (200) can be connected vertically, and accordingly, the first and second channels (200) can form an internal space.

[0031] Meanwhile, the width of the second channel (200) may gradually narrow along the direction of fluid flow, and may gradually narrow toward one side wall of the first channel (100). Accordingly, changes may occur in the internal space of the first and second channels (100, 200).

[0032] Specifically, referring to the AA' cross-section of FIG. 2, the widths (w1, w2) of the first and second channels (100, 200) may each be the same.

[0033] Next, referring to the BB' and CC' cross-sections of FIG. 2, the width of the second channel can gradually narrow in the x-axis direction as the fluid flows in the z-axis direction of FIG. 1.

[0034] Accordingly, the internal space enclosed by the first and second channels (100, 200) may include a first region (R1) having the sum of the heights (h1+h2) of the first and second channels (100, 200) and a second region (R2) having only the height (h1) of the first channel (100). The area of ​​the first region (R1) may gradually decrease, and the area of ​​the second region (R2) may gradually increase.

[0035] The change in area of ​​the first and second regions (R1, R2) described with reference to FIG. 2 can affect the fluid flow, and this will be described later.

[0036] Referring again to FIG. 1, a plurality of outlets (20) may include first and second outlets (22, 24) for separating and discharging particles in a fluid according to their size. The first and second outlets (22, 24) may each be connected to the aforementioned first region (R1) and second region (R2).

[0038] Previously, the structure of a microfluidic element (1) according to one embodiment of the invention was described, and next, the flow of fluid within the microfluidic element (1) will be described in detail.

[0039] The fluid may be various types of fluids containing microparticles, such as blood, seawater, freshwater, and contaminated water. However, in this invention, the fluid will be referred to as blood. The blood may contain red blood cells and white blood cells, as well as foreign substances such as bacteria or cancer cells. Meanwhile, the foreign substances may be smaller in size than red blood cells.

[0040] Referring to FIG. 3, blood is injected into the internal space through the inlet (10) and can flow in the direction of blood flow, i.e., the Z-axis direction, and the speed can increase gradually at the inlet (10) side. Red blood cells (5) and foreign substances (7) in the blood can flow freely in the x-axis direction, which is the transverse direction.

[0041] Next, referring to FIGS. 4 and FIGS. 5, as blood flows in the z-axis direction, the width (W2) of the second channel (200) may gradually decrease, and fluid resistance may decrease in the second region (R2) and fluid resistance may increase in the first region (R1) depending on the change in the cross-sectional area of ​​the space inside the channel.

[0042] However, assuming that the height of the first region (R1) is n times higher than the height of the second region (R2), the width of the second region (R2) is n times the width of the first region (R1). 3 In the case where it is smaller than the ship, the fluid resistance of the first region (R1) has a smaller value than the fluid resistance of the second region (R2).

[0043] Accordingly, the flow rate and movement speed of blood may increase in the first region (R1), which has lower fluid resistance, compared to the second region (R2), which has higher fluid resistance, and as a result, a secondary flow may occur in which blood attempts to move from the second region (R2) to the first region (R1). The secondary flow may increase as the width (W2) of the second channel (200) gradually decreases, and may induce a vortex in the first region (R1) as shown in FIG. 6.

[0044] Meanwhile, red blood cells (5) and foreign substances (7) in the blood can move to the first region (R1) according to the secondary flow. Accordingly, red blood cells (5) and foreign substances (7) can be affected by the vortex. At this time, red blood cells (5), which have a relatively large size and inertia, can be trapped within the first region (R1) by the vortex, or concentrated at a point where the net lift force of the wall-induced lift force (fw) generated between the inner wall of the channel within the first region (R1) and the red blood cells, and the drag force generated by the secondary flow are in equilibrium, that is, at a point where the total net force becomes zero. On the other hand, foreign substances (7), which have a relatively small size and inertia, can circulate along the vortex generated by the secondary flow and flow to the second region (R).

[0045] In this way, red blood cells (5) and foreign substances (7) of different sizes within the blood can be separated according to the flow of fluid and can finally be separated through outlets (20) connected to the first and second regions (R1, R2), respectively. Specifically, blood containing red blood cells (5) can be discharged only through the first outlet (22) connected to the first region (R1), and blood containing foreign substances (7) can be discharged to the outside through the first outlet (22) connected to the first region (R1) and the second outlet (24) connected to the second region (R2).

[0046] Accordingly, unlike conventional microfluidic devices, the present invention can separate particles within a fluid according to size in a simple manner by flowing the fluid without using external forces such as electric force, magnetic force, or acoustic waves, thereby enabling rapid separation of high flow rates. Accordingly, it has the advantage of being applicable in various fields such as rapid diagnosis using blood, fluid purification, microplastic removal, and blood transfusion.

[0048] Previously, the structure and fluid flow of a microfluidic device (1) according to one embodiment of the present invention were described in detail, and next, the components of a microfluidic device (2) of another embodiment will be described.

[0049] Since other embodiments are similar in structure to one embodiment, they will be described by referring again to the drawings referenced earlier; similarly, since the fluid flow according to the structure of other embodiments is the same as that of one embodiment, a description regarding this will be omitted.

[0050] Referring to FIG. 7, a microfluidic element (2) of another embodiment may include first and second channels (100, 200), an inlet (10) and a plurality of outlets (20) formed on one side and the other side of the first and second channels (100, 200), respectively.

[0051] The first channel (100) may be extended in a spiral shape with increasing radius along the direction of fluid flow. In the embodiment illustrated in FIG. 7, the direction of fluid flow may be a circumferential direction in which the fluid travels from the inlet (10) to the outlet (20).

[0052] The second channel (200) can be extended alongside the first channel (100) on the upper side of the first channel (100).

[0053] At this time, referring again to FIG. 2, the inner wall of the first channel (100) can be aligned in a straight line with the inner wall of the second channel (200).

[0054] The first channel (100) and the second channel (200) can be connected vertically, and accordingly, the first and second channels (200) can form an internal space.

[0055] Meanwhile, the width of the second channel (200) may gradually narrow according to the direction of fluid flow, and may gradually narrow toward the inner wall of the first channel (100) where the centrifugal force is minimal. Accordingly, a change may occur in the internal space of the first and second channels (100, 200).

[0056] Specifically, referring again to the AA' cross-section of FIG. 2, the widths (w1, w2) of the first and second channels (100, 200) may each be the same.

[0057] Next, referring again to the BB' and CC' cross-sections of FIG. 2, the width (w2) of the second channel (200) may gradually narrow according to the direction of fluid flow. Accordingly, the internal space enclosed by the first and second channels (100, 200) may include a first region (R1) having the sum of the heights (h1+h2) of the first and second channels (100, 200) and a second region (R2) having only the height (h1) of the first channel (100). The area of ​​the first region (R1) may gradually decrease, and the area of ​​the second region (R2) may gradually increase.

[0058] Referring again to FIG. 7, a plurality of outlets (20) may include first and second outlets (22, 24) that separate and discharge particles in the fluid according to their size. The first and second outlets (22, 24) may each be connected to a first region (R1) and a second region (R2), respectively.

[0060] The process of particle separation due to changes in the cross-sectional area of ​​the first and second regions (R1, R2) is the same as described with reference to FIGS. 3 to 5, so a detailed explanation is omitted here.

[0061] However, in the embodiment illustrated in FIG. 7, due to the difference in centrifugal force applied to the inner wall and the outer wall, the magnitude of the secondary flow may be stronger than in the embodiment illustrated in FIG. 1, and accordingly, the particle separation efficiency may be higher.

[0063] Although the present invention has been described above with reference to the illustrated drawings, the present invention is not limited by the embodiments and drawings disclosed in this specification, and it is obvious that various modifications can be made by a person skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention were not explicitly described while explaining the embodiments of the present invention above, it is natural to acknowledge that the effects predictable by said configuration should also be recognized.

Claims

Claim 1 A microfluidic element comprising: a first channel extending in the longitudinal direction; and a second channel extending parallel to the first channel above the first channel and communicating vertically with the first channel, wherein the width of the second channel is continuously narrowed along the direction of fluid flow. Claim 2 A microfluidic device according to claim 1, wherein one side wall of the first channel and one side wall of the second channel are arranged in a straight line. Claim 3 A microfluidic device according to claim 1, wherein the first and second channels are interconnected to form an internal space, and the internal space includes a first region having the sum of the heights of the first and second channels and a second region having the height of the first channel. Claim 4 In claim 3, a microfluidic device in which, as the width of the second channel narrows, the microparticles in the fluid move toward the first region as the particle size increases. Claim 5 A microfluidic device according to claim 1, further comprising first and second outlets on the other side of the first and second channels for separating and discharging particles in the fluid according to size. Claim 6 A microfluidic element according to claim 3, further comprising first and second outlets connected to the first and second regions. Claim 7 A first channel extending in a spiral shape with increasing radius according to the direction of fluid flow; and a second channel extending parallel to the first channel above the first channel and communicating vertically with the first channel; a microfluidic element in which the width of the second channel continuously narrows according to the direction of fluid flow. Claim 8 A microfluidic device according to claim 7, wherein the width of the second channel gradually narrows toward the inner wall of the first channel where the centrifugal force is minimum, and the inner wall of the first channel and the inner wall of the second channel are aligned in a straight line. Claim 9 A microfluidic device according to claim 7, wherein the first and second channels are interconnected to form an internal space, and the internal space comprises a first region having the sum of the heights of the first and second channels and in contact with the inner walls of the first and second channels, and a second region having the height of the first channel and in contact with the outer walls of the first channel. Claim 10 In claim 9, a microfluidic device in which, as the width of the second channel narrows, the microparticles in the fluid move toward the first region as the particle size increases. Claim 11 A microfluidic device according to claim 7, further comprising first and second outlets on the other side of the first and second channels for separating and discharging particles in the fluid according to size. Claim 12 A microfluidic element according to claim 9, further comprising first and second outlets connected to the first and second regions.

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