Microfluidic device

Abstract

The present application relates to a microfluidic device, comprising: an opening for receiving a test liquid; a main flow path in communication with the opening; and a recovery section provided at an outlet-side end portion of the main flow path. The recovery section comprises: a pool for storing the test liquid; a connecting flow path connecting the pool and the outlet-side end portion; and a protrusion provided in the connecting flow path so as to receive the test liquid discharged from the main flow path and generate a bubble that blocks the connecting flow path between the protrusion and an inner wall of the connecting flow path.

Description

Technical Field

[0001] This disclosure relates to a plate-shaped microfluidic device used in a test in which a test solution containing a sample reacts with a pharmaceutical agent. Background Technology

[0002] For testing the susceptibility of bacteria to antibiotics, methods using microfluidic devices are known. For example, in Japanese Patent Application Publication No. 2017-67620, a microfluidic device is described, comprising an inlet and an outlet connected to the outside, and a flow path for flowing test solution supplied from the inlet towards the outlet. Air is forced into the flow path from the inlet to push the previously introduced test solution into the fine flow path. A reaction section is provided in the flow path to store the test solution supplied from the inlet, and an agent disposed in this reaction section acts on the bacteria.

[0003] Japanese Patent Application Publication No. 2022-044563 discloses a test apparatus in which test liquid is injected into multiple microfluidic paths, and after the test liquid is injected into the microfluidic paths, air pressure is applied to the recovery unit to recover the test liquid in the main flow path connected to the multiple microfluidic paths. Summary of the Invention

[0004] According to the test apparatus disclosed in Japanese Patent Application Publication No. 2022-044563, by discharging the test liquid remaining in the main flow path to the recovery section, multiple microflow paths can be made independent, suppressing the flow of test liquid generated within the flow path. That is, in order to make the multiple microflow paths independent, it is required that the test liquid be reliably discharged from the main flow path to the recovery section, so that the test liquid recovered by the recovery section remains within the recovery section.

[0005] This disclosure was made to solve this technical problem, and its purpose is to keep the test liquid discharged to the recovery section within the recovery section.

[0006] The microfluidic device disclosed herein is a plate-shaped microfluidic device used in tests in which a test solution containing a sample reacts with a reagent. The microfluidic device includes: an opening for receiving the test solution; a main flow path communicating with the opening; multiple microflow paths, each communicating with the main flow path; and a recovery section disposed in the main flow path at an outlet end opposite to the inlet end communicating with the opening, for recovering a portion of the test solution. The recovery section includes: a pool for storing the test solution discharged from the main flow path; a connecting flow path connecting the pool to the outlet end; and a protrusion disposed in the connecting flow path to receive the test solution discharged from the main flow path and to generate air bubbles that block the connecting flow path between the protrusion and the inner wall of the connecting flow path.

[0007] The foregoing description, as well as other objects, features, solutions, and advantages of the present invention, will become clear from the following detailed description relating to the invention, which will be understood in conjunction with the accompanying drawings. Attached Figure Description

[0008] Figure 1 This is a diagram showing an example of the overall configuration of the experimental setup.

[0009] Figure 2 It is a block diagram used to illustrate the control of the experimental apparatus.

[0010] Figure 3 This is a top view of a microflow circuit device.

[0011] Figure 4 This is a flowchart illustrating the pressing method of the test apparatus.

[0012] Figure 5 It is a diagram used to illustrate the flow of the test liquid when it is injected through the test apparatus.

[0013] Figure 6 This is a 3D view of the recycling department.

[0014] Figure 7 This is a cross-sectional view of the recycling section.

[0015] Figure 8 This is a top view of the recycling section.

[0016] Figure 9 It is a diagram schematically showing the state of the recovery section before and after the test solution is discharged.

[0017] Figure 10 This is an image showing the state after the test solution has been drained into the recovery section.

[0018] Figure 11 This is an image showing the state of the test solution after it was drained into the recovery section in the comparative example.

[0019] Figure 12 This is a cross-sectional view of the recycling section in a modified example. Detailed Implementation

[0020] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts in the drawings will be labeled with the same reference numerals, and their descriptions will not be repeated.

[0021] [Test Apparatus Configuration]

[0022] Reference Figure 1 and Figure 2 The test apparatus 100 for injecting test fluid into microfluidic devices is described. Figure 1 This is a diagram showing an example of the overall configuration of the experimental setup. Figure 2This is a block diagram illustrating the control of the test apparatus. Furthermore, the test apparatus of this embodiment is a device for measuring the test solution by injecting a test solution containing a sample into the microfluidic path of a microfluidic device. As an example, the following describes an example of injecting a test solution into the microfluidic path to measure the sensitivity of bacteria to an antibacterial agent (pharmaceutical). The test solution contains a sample. The sample can be a bacterium (in this specific example, a pathogenic bacterium). In this specific example, the test solution can also be a bacterial suspension. Of course, the test solution is not limited to the above-described test solution, as long as it is injected into the microfluidic path of the microfluidic device by the test apparatus.

[0023] Reference Figures 1-2 The test apparatus 100 includes a test liquid setting unit 10, a pipette nozzle driving unit 12, a worktable driving unit 13, a pump 14, a pipette nozzle 15, a worktable 16, an opening and closing unit 30, an opening and closing driving unit 31, a coating unit 32, a pump 33, a coating driving unit 34, and a control unit 50.

[0024] The test solution setting section 10 is a bracket capable of arranging multiple test solution containers 5 containing test solutions. The test solution setting section 10 can arrange multiple test solution containers 5 relative to the test apparatus 100 on a bracket basis.

[0025] The pipette nozzle 15 is equipped with a detachable pipette tip 1, through which the test liquid is drawn from or discharged from the test liquid container 5.

[0026] The pipette nozzle drive unit 12 horizontally moves the pipette nozzle 15, the pump 14 connected to the pipette nozzle 15, the opening / closing part 30, the coating part 32, and the pump 33 connected to the coating part 32. Furthermore, the pipette nozzle drive unit 12 vertically moves the pipette nozzle 15 and the pump 14 connected to the pipette nozzle 15. The pipette nozzle drive unit 12 can, for example, move the pipette nozzle 15 freely via a solenoid actuator or a stepper motor.

[0027] The stage 16 is used to mount the microfluidic device 2 (see reference). Figure 3 The stage 16 is formed as a flat plate, and the microfluidic device 2 is fixed on its upper surface. The stage drive 13 enables the stage 16 to move horizontally. The stage drive 13 can move the stage 16 freely, for example, by means of a solenoid actuator or a stepper motor. Of course, the stage drive 13 can also move the stage 16 up and down, instead of moving the pipette nozzle 15 up and down. In addition, at least the pipette nozzle drive 12 and the stage drive 13 are moving mechanisms for changing the relative position of the pipette nozzle 15 and the microfluidic device 2.

[0028] Although not shown, pump 14 includes, for example, a syringe, a plunger that reciprocates within the syringe, and a drive motor for driving the plunger. When connected to the pipette nozzle 15 via tubing, pump 14, by reciprocating the plunger, can adjust the air pressure within the pipette tip 1, thereby drawing the test solution into the pipette tip 1 or expelling the test solution from the pipette tip 1. Furthermore, while expelling the test solution from the pipette tip 1, pump 14 can further move the plunger towards the syringe, thereby expelling air from the pipette tip 1.

[0029] The opening / closing part 30 is the opening 29 formed in the microfluidic device 2 (see below) described later. Figure 3 The opening and closing mechanism 30 includes an elastic member 30a disposed at the front end of a rod-shaped support portion. The elastic member 30a is, for example, silicone resin. The opening and closing drive unit 31 drives the opening and closing unit 30, causing the elastic member 30a to move up and down. The opening and closing drive unit 31 moves the elastic member 30a, which is positioned directly above the opening 29, up and down, thereby pressing or separating the elastic member 30a from the gas-permeable membrane 27a covering the opening 29. Thus, the opening and closing unit 30, equipped with the elastic member 30a, opens and closes the opening 29. Figure 1 The diagram shows a configuration in which the opening and closing part 30 is provided in the same moving mechanism as the pipette nozzle 15. However, the opening and closing part 30 can also be provided in a different moving mechanism than the pipette nozzle 15, and the opening and closing part 30 can be moved by the opening and closing drive part 31.

[0030] The coating section 32 applies a sealing material to openings or other openings formed in the microfluidic device 2. The coating section 32 may be, for example, a nozzle that discharges a sealing material such as silicone oil into the openings or other openings, and a pump 33 applies the sealing material to the openings or other openings through this nozzle. The configuration of the coating section 32 is not limited to this; it may also be a mechanism that applies the sealing material to the openings or other openings using a brush or the like.

[0031] The coating drive unit 34 moves the coating unit 32 to the position where the sealing material is coated, and drives the pump 33. Figure 1 The diagram shows a configuration in which the coating section 32 is mounted on the same moving mechanism as the pipette nozzle 15. However, the coating section 32 can also be mounted on a different moving mechanism than the pipette nozzle 15, and the coating section 32 can be moved by the coating drive section 34.

[0032] The control unit 50 controls the operation of the test apparatus 100. The control unit 50 includes a processor such as a CPU (Central Processing Unit), and memory such as ROM (Read Only Memory) and RAM (Random Access Memory). The memory stores the control program. The processor controls the operation of the test apparatus 100 by executing the control program. Alternatively, the memory of the control unit 50 may also include an HDD (Hard Disk Drive).

[0033] like Figure 2 As shown, the control unit 50 controls the test liquid setting unit 10, the pipette nozzle drive unit 12, the worktable drive unit 13, the pump 14, the opening and closing drive unit 31, the pump 33, and the coating drive unit 34. The control unit 50 controls these components, thereby injecting the test liquid into the microfluidic device 2 placed on the worktable 16, or applying sealing material to openings formed in the microfluidic device 2. Furthermore, the specific operation of the test apparatus 100 will be explained with reference to... Figure 4 As will be described below.

[0034] Alternatively, a computing device such as a computer used by the user to manage the testing apparatus 100 can be connected to the control unit 50. The computing device may receive inputs such as the amount of movement of the stage 16 and the amount of test liquid injected into the microfluidic device 2.

[0035] [The structure of microflow circuit devices]

[0036] Figure 3 This is a top view of the microfluidic device. The microfluidic device 2 is placed on the worktable 16 of the experimental apparatus 100. Furthermore, in the following description, the surface of the microfluidic device 2 with the opening 22 is referred to as the XY plane, and the axis orthogonal to the XY plane is referred to as the Z-axis. Additionally, the surface with the opening 22 is sometimes referred to as the upper surface, and the surface opposite to this upper surface is referred to as the bottom surface; the positive direction of the Z-axis is called "up," and the negative direction is called "down."

[0037] The microfluidic device 2 is placed on the worktable 16 with its bottom surface, which does not have the opening 22, as the mounting surface. For example... Figure 3 As shown, the microflow device 2 includes a plate-shaped component 20 and a flow path structure. The flow path structure includes an opening 22, a main flow path 23, a microflow path 24, a storage section 25, an opening 26, and a recovery section 40 with an opening 29.

[0038] The opening 22 is connected to the inlet-side end 23a, which serves as one end of the main flow path 23, and is thus in communication with the main flow path 23. Fluid pressure is used to force the test liquid from the opening 22 into the main flow path 23. The test liquid forced into the main flow path 23 is further forced into the microflow path 24. In this embodiment, air pressure is used as the fluid pressure. The opening 22 is, for example, circular in cross-section. The diameter of the opening 22 is, for example, 5 μm to 5 mm. In this embodiment, one main flow path 23 is connected to the opening 22. The main flow path 23 is positioned outside the plurality of microflow paths 24.

[0039] The main flow path 23 has an inlet-side end 23a communicating with the opening 22 and an outlet-side end 23b located on the opposite side of the inlet-side end 23a. Extending from the opening 22, the main flow path 23 further branches into multiple microflow paths 24. The main flow path 23 connects to the multiple microflow paths 24, allowing the test liquid to flow. The test liquid flowing in from the opening 22 flows through the main flow path 23 to the branched microflow paths 24. The cross-section of the main flow path 23 and the microflow paths 24 is rectangular, and their widths are, for example, 1 μm to 1 mm. However, the depths (heights) of the main flow path 23 and the microflow paths 24 differ. For example, the depth of the main flow path 23 is 0.5 mm, while the depth of the microflow path 24 is smaller, at 0.025 mm. Therefore, the flow resistance of the microflow path 24 is greater than that of the main flow path 23. By increasing the flow resistance of the microflow path 24 compared to the main flow path 23, as described later, the test liquid flowing in from the opening 22 can flow in almost simultaneously relative to the multiple microflow paths 24 after temporarily filling the main flow path 23.

[0040] In this embodiment, the 32 microflow paths 24 arranged in the X-axis direction are designated as one group, and two groups are arranged in the Y-axis direction. That is, the microflow path device 2 has a first group on the positive Y-axis side and a second group on the negative Y-axis side. Each of the multiple microflow paths 24 has a first side end 24a that communicates with the main flow path 23, and a second side end 24b located on the opposite side of the first side end 24a.

[0041] The multiple microfluidic paths 24 included in the first group are connected to the main flow path 23 disposed on the positive Y-axis side of the microfluidic path device 2. Furthermore, the multiple microfluidic paths 24 included in the first group are connected to the main flow path 23 with their first end 24a located on the positive Y-axis side and their second end 24b located on the negative Y-axis side. Therefore, the test liquid flowing from the main flow path 23 to the branches of the multiple microfluidic paths 24 included in the first group flows in the negative Y-axis direction.

[0042] On the other hand, the multiple microfluidic paths 24 included in the second group are each connected to the main flow path 23 disposed on the negative Y-axis side of the microfluidic device 2. Furthermore, the multiple microfluidic paths 24 included in the second group are connected to the main flow path 23 with their first end 24a located on the negative Y-axis side and their second end 24b located on the positive Y-axis side. Therefore, the test liquid flowing from the main flow path 23 to the branches of the multiple microfluidic paths 24 included in the second group flows in the positive Y-axis direction.

[0043] After branching from the main flow path 23 into multiple microflow paths 24, storage sections 25 are provided in the middle of each microflow path 24. Therefore, the test liquid flowing in from the opening 22 flows through the main flow path 23 and the microflow paths 24 to each storage section 25.

[0044] The storage section 25 contains a reagent and is connected to the opening 22 via the main flow path 23 and the microflow path 24, storing the test solution flowing in from the opening 22. In the storage section 25, the test solution reacts with the reagent. The reagent is, for example, an antibacterial agent. The reagent can be solid or liquid. The reagent is pre-loaded into the storage section 25. That is, the reagent is placed in the storage section 25 before the test solution flows into it. In this embodiment, the reagent is coated throughout the storage section 25.

[0045] The storage section 25 is formed in a cuboid shape. The length of one side of the storage section 25 is, for example, 10 μm to 10 mm.

[0046] exist Figure 3 In this design, 64 (32 x 2) storage compartments 25 are formed in the plate-shaped component 20. The test solution stored in each of the 64 storage compartments 25 has the same capacity. On the other hand, the types and amounts of the reagents placed in the 64 storage compartments 25 can be the same or different from each other.

[0047] A microflow path 24 is provided between the storage section 25 and the opening 26. The microflow path 24 is arranged along the Y-axis, with one end connected to the storage section 25 and the other end (second side end 24b) connected to the opening 26. The microflow path 24 allows the test liquid flowing into the storage section 25 to flow further to the opening 26.

[0048] The opening 26 is connected to the other end (second side end 24b) of the microflow path 24. The opening 26 has a circular cross-section, for example. The diameter of the opening 26 is, for example, 5 μm to 5 mm.

[0049] Opening 26 is covered by gas-permeable membrane 27. Specifically, in Figure 3In the microfluidic device 2, 32 openings 26 connected to the first group of microfluidic paths 24 arranged on the positive Y-axis side and 32 openings 26 connected to the second group of microfluidic paths 24 arranged on the negative Y-axis side are respectively arranged in a relative manner. Therefore, 64 (=32 × 2) openings 26 are arranged along the X-axis in the central portion of the microfluidic device 2. These 64 openings 26 are covered by a gas-permeable membrane 27. Alternatively, instead of using only one gas-permeable membrane 27 to cover the 64 openings 26, two gas-permeable membranes 27 may be used to cover the 32 openings 26 in the first group and the 32 openings 26 in the second group, respectively. Furthermore, the gas-permeable membrane 27 may also cover at least one of the 64 openings 26.

[0050] The gas permeable membrane 27 has the function of allowing gas to pass through but preventing liquid from passing through. Examples of materials for the gas permeable membrane 27 include polytetrafluoroethylene (PTFE). The gas permeable membrane 27 preferably has water-repellent properties. The thickness of the gas permeable membrane 27 is 1 mm or less.

[0051] The gas-permeable membrane 27 is fixed to the plate-shaped component 20 by bonding with an adhesive, ultrasonic welding, or other means. Examples of adhesives include photocurable resins, thermocurable resins, and pressure-sensitive resins.

[0052] A recovery unit 40 is provided at the outlet end 23b of the main flow path 23. The recovery unit 40 recovers a portion of the test liquid flowing into the main flow path 23 from the opening 22.

[0053] An opening 29 is provided at the upper part of the recovery section 40. The opening 29 is covered by a gas permeable membrane 27a. The structure from the opening 22 to the recovery section 40 is configured such that the test liquid can flow through the main flow path 23. The opening 29 can be opened or closed by pressing or separating the elastic member 30a of the opening / closing section 30 of the test apparatus 100 from above the gas permeable membrane 27a.

[0054] The connection flow path 44 provided in the recycling section 40 (see reference) Figure 7 The cross-sectional area of ​​the recovery section 40 is larger than that of each flow path in the microflow path 24 and the main flow path 23. Therefore, the flow resistance of the recovery section 40 is smaller compared to the microflow path 24 and the main flow path 23. By reducing the flow resistance of the recovery section 40 compared to the microflow path 24 and the main flow path 23, if air is introduced from the opening 22 with the opening 29 open, the test liquid remaining in the main flow path 23 will be discharged into the recovery section 40.

[0055] That is, by closing the opening 29, the test device 100 prevents the test liquid flowing into the main flow path 23 from being discharged to the recovery section 40; by opening the opening 29, the test liquid remaining in the main flow path 23 is discharged to the recovery section 40 and recovered.

[0056] The gas-permeable membrane 27a can be made of the same material as the gas-permeable membrane 27 covering the opening 26, or it can be made of a different material, as long as it has the function of allowing gas to pass through while preventing liquid from passing through. Examples of materials for the gas-permeable membrane 27a include polytetrafluoroethylene (PTFE). The gas-permeable membrane 27a preferably has water-repellent properties. The thickness of the gas-permeable membrane 27a is 1 mm or less. The gas-permeable membrane 27a is fixed to the plate-shaped component 20 by bonding with an adhesive, ultrasonic welding, or the like. Examples of adhesives include photocurable resins, thermocurable resins, and pressure-sensitive resins.

[0057] By providing the gas-permeable membrane 27a, the risk of test liquid overflowing from the opening 29 can be reduced when the test liquid is discharged to the recovery section 40. Alternatively, if the size of the recovery section 40 is sufficiently ensured to minimize the possibility of test liquid overflowing from the opening 29, the gas-permeable membrane 27a may not be required.

[0058] Furthermore, the main flow path 23 has a sealing portion 28 between the connecting portion 24c and the outlet end 23b. This connecting portion 24c is connected to the microflow path 24 located closest to the outlet end 23b among the plurality of microflow paths 24. After the test liquid is discharged into the recovery section 40, the sealing portion 28 is sealed. Thus, the main flow path 23 and the recovery section 40 are physically blocked and made independent of each other, thereby reliably preventing the test liquid discharged into the recovery section 40 from flowing back into the main flow path 23 (microflow path 24). There is no particular limitation on the method of sealing the sealing portion 28. For example, it can be sealed by injecting silicone oil as a sealing material, or it can be sealed by embedding a sealing component into the sealing portion 28. In this embodiment, as an example, the sealing material coated by the coating portion 32 is injected into the sealing portion 28. In addition, when the method of sealing the opening 22, etc., is different from the method of sealing the sealing portion 28, the test apparatus 100 has the function of implementing each sealing method.

[0059] Furthermore, the main flow path 23 may also have a sealing portion between the connection portion and the inlet-side end 23a, which is a connection portion that connects to the microflow path 24 located closest to the inlet-side end 23a among the plurality of microflow paths 24. Similar to the sealing portion 28, the sealing portion located near the inlet-side end 23a is sealed after the test liquid is discharged to the recovery portion 40. This physically blocks the opening 22 from the main flow path 23, making them independent of each other, thereby reliably preventing the test liquid in the main flow path 23 from flowing into the opening 22. Furthermore, the sealing method is not particularly limited.

[0060] [Method for pressing in the test apparatus]

[0061] Figure 4 This is a flowchart illustrating the pressing method of the test apparatus. (Refer to...) Figure 4 The pressing method of the test apparatus 100 in this embodiment will be described. First, the control unit 50 of the test apparatus 100 controls the motor of the pipette nozzle drive unit 12 to move the pipette nozzle 15 to the position of the predetermined test liquid container 5, and controls the pump 14 to draw the test liquid from the front end of the pipette tip 1 into the test liquid container 5 (step S11). The control unit 50 controls the motor of the pipette nozzle drive unit 12 to move the pipette nozzle 15 to the position of the opening 22 of the microfluidic device 2 (step S12).

[0062] Here, the position of the opening / closing part 30 relative to the pipette nozzle 15 is predetermined based on the position of the opening 29 of the recovery part 40 relative to the opening 22 of the microfluidic device 2. More specifically, the position of the opening / closing part 30 is predetermined such that when the pipette nozzle 15 is moved to the position of the opening 22, the elastic member 30a of the opening / closing part 30 is located above the opening 29. Therefore, when the pipette nozzle 15 is aligned with the opening 22 of the microfluidic device 2 in step S12, the elastic member 30a of the opening / closing part 30 moves to a position directly above the opening 29 of the recovery part 40. Alternatively, the opening / closing part 30 can be moved by a different moving mechanism than the moving mechanism (pipette nozzle drive part 12) that moves the pipette nozzle 15.

[0063] The control unit 50 controls the opening / closing drive unit 31 to move the elastic member 30a to the position of the opening 29 of the blocking and recovery unit 40 (step S13). More specifically, the control unit 50 presses the elastic member 30a against the gas permeable membrane 27a, thereby blocking the entire opening 29 with the elastic member 30a.

[0064] After closing the opening 29, the control unit 50 controls the pump 14 to discharge the test liquid from the front end of the pipette tip 1 and press the test liquid into the flow path (main flow path 23, micro flow path 24) of the microflow device 2 (step S14).

[0065] The control unit 50 determines whether the test liquid has been injected into all the flow paths of the microfluidic devices 2 (step S15). Furthermore, the control unit 50 determines whether the test liquid has been injected into all the flow paths of the microfluidic devices 2 based, for example, on the time it took to inject the test liquid into the flow paths of the microfluidic devices 2 and the remaining amount of test liquid in the pipette tip 1. If the test liquid has not been injected into all the flow paths of the microfluidic devices 2 (no in step S15), the control unit 50 returns the process to step S14.

[0066] When the test liquid has been injected into all the flow paths of the microfluidic device 2 (yes in step S15), the control unit 50 controls the opening / closing drive unit 31 to move the elastic member 30a from the position of the blocked opening 29, opening the opening 29 (step S16). The control unit 50 controls the pump 14 to discharge air from the front end of the pipette tip 1, discharging the test liquid remaining in the main flow path 23 to the recovery unit 40 (step S17).

[0067] The control unit 50 controls the pipette nozzle drive unit 12 and the coating drive unit 34 to inject sealing material into the sealing part 28 (step S18). More specifically, the control unit 50 controls the pipette nozzle drive unit 12 to move the coating part 32 directly above the sealing part 28. Then, the control unit 50 controls the coating drive unit 34 to move the coating part 32 to a position where sealing material can be injected into the sealing part 28. Then, the control unit 50 drives the pump 33 to inject sealing material into the sealing part 28.

[0068] The control unit 50 controls the pipette nozzle drive unit 12 to move the coating unit 32 to the positions of the openings 22, 26, and 29, and controls the coating drive unit 34 to apply sealing material to the openings 22, 26, and 29 (step S19).

[0069] By controlling the process as described above, the test apparatus 100 presses the test liquid into the microfluidic device 2 and discharges the test liquid into the recovery section 40, and applies sealing material to the openings formed in the microfluidic device 2.

[0070] Figure 5 This diagram illustrates the flow of the test liquid when it is injected through the test apparatus. With opening 29 closed and opening 26 open, the test apparatus 100 injects the test liquid through opening 22 into the main flow path 23. As the test liquid flows into the main flow path 23, the flow resistance of each microflow path 24 is greater than that of the main flow path 23; therefore, as... Figure 5 As shown in the upper section, firstly, the main flow path 23 is filled with the test solution. After the main flow path 23 is completely filled with the test solution, as... Figure 5 As shown in the middle section, the test liquid flows into each microfluidic path 24. At this time, since the opening 26 is open and the opening 29 is closed, the test liquid does not flow into the recovery section 40, but flows into each microfluidic path 24 and the storage section 25.

[0071] After each microfluidic path 24 and the storage section 25 is filled with the test liquid, the test apparatus 100 removes the elastic member 30a that blocks the opening / closing section 30 of the opening 29, and air is introduced through the opening 22 with the opening 29 open. The result is as follows: Figure 5 As shown in the lower section, the test liquid remaining in the main flow path 23 is discharged to the recovery section 40. In addition, the air introduced from the opening 22 can utilize the air discharged from the pipette tip 1 for pressing in the test liquid.

[0072] Here, although the opening 26 is open, the test liquid in the main flow path 23 will not be pushed out to the microflow path 24, but will be discharged to the recovery section 40 because the flow resistance of the microflow path 24 is greater than that of the recovery section 40.

[0073] In the microfluidic device 2, the test liquid flowing in from the pipette tip 1 passes through the opening 22 and the main flow path 23, filling the microfluidic path 24, the storage section 25, and the opening 26. The multiple microfluidic paths 24 of the microfluidic device 2 are connected via the main flow path 23. Therefore, when the test liquid is injected, if there is a difference in the liquid level (liquid head) between the flow paths or at the portion from the opening 22 to each flow path, the test liquid will flow within each flow path due to this difference. For example, if there is a difference in liquid head between the multiple microfluidic paths 24, the test liquid will flow between the flow paths to eliminate this difference. As a result, the test liquid flows within the storage section 25 of the microfluidic path 24, which may prevent the observation of accurate results.

[0074] In this embodiment, the test apparatus 100, after pumping the test liquid into the flow path (main flow path 23, micro flow path 24) of the microflow device 2, discharges the test liquid remaining in the main flow path 23 to the recovery section 40. This allows each of the multiple microflow paths 24 to operate independently. As a result, even if a height difference in liquid level occurs between the multiple microflow paths 24, the flow of the test liquid caused by this height difference can be prevented.

[0075] [Structure of the Recycling Department]

[0076] Figure 6 This is a 3D view of the recycling department. Figure 7 This is a cross-sectional view of the recycling section. Figure 8 This is a top view of the recovery section. (See reference) Figures 6-8 The structure of the recycling unit 40 will be explained. Figure 6 This refers to the component whose bottom surface, which forms the flow path, is opposite to the surface with the opening, after removal. Figure 7 A perspective view of the retraction section 40 viewed from the bottom side, showing the second plate-shaped member 20b) in its current state. Furthermore, in Figure 8 For convenience, the description of gas permeable membrane 27a has been omitted.

[0077] The recovery unit 40 includes a tank 42 for storing the test liquid, a connecting flow path 44 connecting the tank 42 to the outlet end 23b, and a protrusion 46 provided in the connecting flow path 44.

[0078] An opening 29 is provided at the top of the pool 42. The opening 29 is covered by a gas-permeable membrane 27a. The pool 42 is a space for storing the test liquid discharged from the main flow path 23. The volume of the pool 42 is larger than the overall volume of the main flow path 23. Therefore, all the test liquid remaining in the main flow path 23 can be recovered into the pool 42. For example, when the depth of the main flow path 23 is 0.01 mm to 0.05 mm and the width is 0.1 mm to 1 mm, the diameter of the pool 42 is 10 mm to 15 mm and the depth is 1 mm to 5 mm. As an example, when the depth of the main flow path 23 is 0.03 mm and the width is 0.5 mm, the diameter of the pool 42 is 8 mm and the depth is 2.5 mm.

[0079] The connecting flow path 44 includes a straight flow path 450 extending from the outlet end 23b and an inclined flow path 440 communicating with the straight flow path 450. The inclined flow path 440 is configured such that the cross-sectional area of ​​the flow path increases from the straight flow path 450 toward the pool 42, that is, from the outlet end 23b toward the pool 42.

[0080] At least one inclined surface 442 is formed in the inclined flow path 440, which is inclined toward the outside of the inclined flow path 440. In this embodiment, three inclined surfaces 442 are formed in the inclined flow path 440. More specifically, the inclined surfaces 442 are formed on two surfaces constituting the side of the inclined flow path 440 and on the side surface where the openings 29 and 22 are formed.

[0081] More specifically, a first inclined surface 444, a second inclined surface 446, and a third inclined surface 448 are formed in the inclined flow path 440. The first inclined surface 444 is formed on the side where the openings 29 and 22 are formed. The second inclined surface 446 and the third inclined surface 448 constitute a tapered portion where the width of the flow path widens from the outlet end 23b toward the pool 42. For example, for the inclined flow path 440, the width of the end on the straight flow path 450 side is 0.1 mm to 1 mm, and the depth is 0.01 mm to 0.05 mm. The width of the end on the pool 42 side is 5 mm to 6 mm, and the depth is 1 mm to 5 mm. The length from the end on the main flow path 23 side to the end on the pool 42 side is 2 mm to 6 mm.

[0082] The angle of inclination θa relative to the flow path extending from the inclined surface 442 is less than 90 degrees. More specifically, the angle of inclination θ1 of the first inclined surface 444 relative to the horizontal surface 452 is less than 90 degrees. The angle of inclination θ2 of the second inclined surface 446 relative to the first side surface 454 is less than 90 degrees. Furthermore, the angle of inclination θ3 of the third inclined surface 448 relative to the second side surface 456 is less than 90 degrees. In addition, the cone angle θb of the cone formed by the second inclined surface 446 and the third inclined surface 448 is less than 180 degrees. The angle of inclination θa is, for example, 15 degrees to 45 degrees. Furthermore, the angles of inclination θ1, θ2, and θ3 can be the same angle or different angles.

[0083] The protrusion 46 is disposed in the connecting flow path 44 to receive the test liquid discharged from the main flow path 23 and to generate air bubbles that block the connecting flow path 44 between itself and the inner wall of the connecting flow path 44. If air is introduced from the opening 22, the test liquid remaining in the main flow path 23 is discharged to the recovery section 40. The test liquid and air collide with the protrusion 46, and air bubbles are generated between the inner wall of the connecting flow path 44 and the protrusion 46 at the boundary between the test liquid and air in the connecting flow path 44. Since the cross-sectional area of ​​the flow path between the protrusion 46 and the inner wall of the connecting flow path 44 is small, the connecting flow path 44 is blocked by the air bubbles. In addition, the air bubbles remain in the connecting flow path 44 due to surface tension. As a result, the discharged test liquid is prevented from flowing back into the main flow path 23 by the air bubbles.

[0084] In this embodiment, the protrusion 46 is disposed in the inclined flow path 440 with the inclined surface 442 as the disposed surface. More specifically, the disposed surface of the protrusion 46 is the first inclined surface 444. When viewed from above, the protrusion 46 has a shape that tapers towards the tip of the outlet-side end 23b. The protrusion 46 has a degree to which it does not completely block the flow path of the inclined flow path 440.

[0085] For example, when viewed from above, the protrusion 46 has a size such that a flow path with a width similar to that of the straight flow path 450 or the main flow path 23 is formed on both sides of the protrusion 46. For example, when viewed from above, the protrusion 46 has a size such that the distance between the protrusion 46 and the inner wall of the inclined flow path 440 is 0.1 mm to 1 mm. More specifically, for the inclined flow path 440, if the width at the end on the main flow path 23 side is 0.5 mm and the depth is 0.03 mm, the width at the end on the pool 42 side is 5.5 mm and the depth is 2.5 mm, and the length from the end on the main flow path 23 side to the end on the pool 42 side is 4 mm, the size of the protrusion 46 is as follows. The protrusion 46 is a square pyramidal shaped like an equilateral triangle with one side of 1 mm when viewed from above. In this case, when viewed from above, the microflow path device 2 has flow paths with a width of 0.5 mm on both sides of the protrusion 46.

[0086] By providing the protrusion 46, sufficiently large bubbles can be generated. In addition, by making the flow path cross-sectional area around the protrusion 46 and the flow path cross-sectional area of ​​the straight flow path 450 sufficiently small, the bubbles generated by the protrusion 46 can block the connecting flow path 44 and remain in the connecting flow path 44 due to surface tension.

[0087] The plate-shaped component 20 includes a first plate-shaped component 20a having multiple openings and flow paths, and a second plate-shaped component 20b stacked on top of the first plate-shaped component 20a. The thickness of the first plate-shaped component 20a and the second plate-shaped component 20b is not particularly limited, and is set to, for example, 0.5 mm to 3 mm. In addition, the second plate-shaped component 20b is directly fixed to the first plate-shaped component 20a by ultrasonic melting, but it can also be fixed by adhesive.

[0088] The first plate-shaped component 20a and the second plate-shaped component 20b are formed of a transparent material and are rectangular plates when viewed from above. Examples of materials for the first plate-shaped component 20a and the second plate-shaped component 20b include acrylic resins such as polymethyl methacrylate resin and glass.

[0089] An opening and flow path structure are formed in the first plate-shaped member 20a. More specifically, the first plate-shaped member 20a has an opening 22, a main flow path 23, a micro flow path 24, a storage section 25, an opening 26, and a recovery section 40 with an opening 29.

[0090] The second plate-shaped component 20b is a flat component and functions as the bottom surface of each flow path. More specifically, it functions as the lower surface of the opening 22, the main flow path 23, the microflow path 24, the storage section 25, the opening 26, and the recovery section 40. Specifically, the surface opposite to the surface where the opening 22 is formed (the surface formed by the second plate-shaped component 20b) of the wall surface constituting each flow path of the microflow path device 2 is flat.

[0091] Figure 9 It is a diagram schematically showing the state of the recovery section before and after the test solution is discharged. Figure 10 This is an image showing the state after the test solution has been drained into the recovery section. Figure 11 This image shows the state of the test solution after it has been discharged into the recovery section in the comparative example. No protrusions are provided in the connecting flow path 90 of the comparative example.

[0092] The test apparatus 100 discharges air from the front end of the pipette tip 1 to discharge the test liquid remaining in the main flow path 23 to the recovery section 40. If the air pressure applied during the discharge of the test liquid is released, the test liquid in the connecting flow path 44 may sometimes flow back into the main flow path 23 through capillary action, requiring the test liquid to remain in the recovery section 40.

[0093] When air is introduced through opening 22 to discharge the test liquid remaining in the main flow path 23 into the pool 42, the air and test liquid introduced through opening 22 collide with the protrusion 46, thereby generating bubbles A at the boundary between the test liquid and air. Figure 9 As shown in the lower section, the generated bubble A has the size to block the connecting flow path 44. More specifically, as Figure 10 As shown, a large bubble A is generated in the connecting flow path 44 where the protrusion 46 is provided, to the extent of blocking the connecting flow path 44. On the other hand, as... Figure 11 As shown, in the connecting flow path 90 without protrusions, although small air bubbles are generated, no bubbles are generated as shown in the diagram. Figure 10 The large bubble A is shown as representing a blockage in the flow path 44. Furthermore, as... Figure 10 As shown, since the protrusion 46 is disposed on the connecting flow path 44, the flow path cross-sectional area is small, and the flow path between the protrusion 46 and the inner wall of the connecting flow path 44 is blocked by the generated air bubbles.

[0094] In this way, when the test liquid is discharged from the main flow path 23, bubbles A are generated by the protrusions 46, which can block the connecting flow path 44. The generated bubbles A remain in the connecting flow path 44 due to surface tension. By the bubbles A remaining in the connecting flow path 44, backflow of the test liquid from the recovery section 40 to the main flow path 23 can be prevented, and as a result, the test liquid can be retained in the recovery section 40.

[0095] While bubble A remains within the connecting flow path 44, backflow of the test liquid can be prevented. However, if bubble A moves from the connecting flow path 44 to the pool 42 or the main flow path 23, this effect will not be achieved. In this embodiment, after the test liquid is discharged to the recovery section 40, the test apparatus 100 injects sealing material into the sealing section 28 as early as possible, before applying sealing material to the openings 26 and 29 respectively. This reliably prevents backflow of the test liquid into the main flow path 23.

[0096] Furthermore, in order to achieve the purpose of recovering the test liquid from the main flow path 23, the recovery unit 40 has a pool 42 with a volume larger than that of the main flow path 23. When it is desired to form a pool 42 with a volume larger than that of the main flow path 23 within the plate-shaped component 20, it is necessary to increase the cross-sectional area of ​​the pool 42 in order to achieve miniaturization of the microflow path device 2 and reduce flow path resistance. Therefore, the connecting flow path 44 is shaped to expand the flow path in either the depth or width direction. In this embodiment, the recovery unit 40 has an inclined flow path 440 with an inclined surface 442 having an inclination angle θa of less than 90 degrees, thereby expanding the flow path cross-sectional area from the outlet end 23b toward the pool 42.

[0097] Here, when the inclination angle θ1 of the first inclined surface 444 relative to the horizontal surface 452 is 90 degrees or more, the angle formed by the first inclined surface 444 and the upper surface of the flow path becomes less than 90 degrees. Therefore, the distance between the first inclined surface 444 and the upper surface of the flow path becomes closer. As a result, the test liquid sometimes remains at the boundary between the first inclined surface 444 and the upper surface of the flow path. In this embodiment, the inclination angle θa is less than 90 degrees. Therefore, it is possible to prevent the test liquid from remaining at the boundary between the inclined surface 442 and the flow path extending from the inclined surface 442. That is, it is possible to prevent test liquid from remaining in the connecting flow path 44, and as a result, it is possible to prevent the backflow of test liquid from the recovery section 40 to the main flow path 23.

[0098] Furthermore, in this embodiment, the protrusion 46 has a shape that tapers towards the tip of the outlet-side end 23b. As a result, it is possible to prevent the test liquid from remaining at the boundary between the protrusion 46 and the surface on which the protrusion 46 is disposed. That is, it is possible to prevent the test liquid from remaining in the connecting flow path 44, and as a result, it is possible to prevent the backflow of the test liquid from the recovery section 40 to the main flow path 23.

[0099] Furthermore, in this embodiment, the protrusion 46 is provided in the inclined flow path 440, which has an inclined surface 442, within the connecting flow path 44. The inclined flow path 440 is a flow path with an enlarged cross-sectional area. Therefore, the protrusion 46 can be easily provided.

[0100] The second plate-shaped component 20b is a flat component, serving as the bottom surface of each flow path. That is, among the wall surfaces of each flow path constituting the microfluidic device 2, the surface opposite to the surface where the opening 22 is formed, i.e., the surface formed by the second plate-shaped component 20b, is flat. Therefore, the flow path structure can be simplified, and the microfluidic device 2 can be easily manufactured.

[0101] Furthermore, the connecting flow path 44 according to this embodiment includes a cone formed by a second inclined surface 446 and a third inclined surface 448. Since the cone angle θb of the cone is less than 180 degrees, it is possible to prevent the test liquid from remaining at the boundary between the cone and the flow path extending from the cone, that is, the boundary between the second inclined surface 446 and the flow path extending from the second inclined surface 446, and the boundary between the third inclined surface 448 and the flow path extending from the third inclined surface 448. In other words, it is possible to prevent the test liquid from remaining in the connecting flow path 44, and as a result, it is possible to prevent the backflow of the test liquid from the recovery section 40 to the main flow path 23.

[0102] Furthermore, in this embodiment, by further providing a tapered portion in the inclined flow path 440 where the first inclined surface 444 is formed, the cross-sectional area of ​​the flow path can be drastically increased. Therefore, the length of the connecting flow path 44 can be shortened, which helps to achieve miniaturization of the microflow path device 2.

[0103] [Variation Example]

[0104] In the above embodiment, an inclined surface 442 with an inclination angle θa less than 90 degrees is formed in the connecting flow path 44. Alternatively, the connecting flow path 44 may also have an inclined surface with an inclination angle θa of 90 degrees. Figure 12 This is a cross-sectional view of the recovery section in a modified example. The recovery section 40a may also have an inclined surface 442a with an inclination angle θa of 90 degrees. Even with an inclination angle θa of 90 degrees, bubbles can be formed by providing protrusions 46, and the flow path between the main flow path 23 and the pool 42 is blocked by the generated bubbles, preventing the backflow of the test liquid from the recovery section 40 to the main flow path 23.

[0105] In the above embodiment, the protrusion 46 is formed on the inclined surface 442. In addition, the protrusion 46 can be provided only in the connecting flow path 44 between the pool 42 and the outlet side end 23b, for example, it can also be provided in the straight flow path 450.

[0106] In this embodiment, the inclined flow path 440 includes a tapered portion formed by a second inclined surface 446 and a third inclined surface 448. Alternatively, the inclined flow path 440 may not include the tapered portion.

[0107] In the above embodiment, the opening 29 is provided at the upper part of the pool 42. Alternatively, the pool 42 may be further connected to another flow path, with the opening 29 provided in that flow path. Furthermore, in this case, the opening 29 is preferably covered by a gas-permeable membrane 27a.

[0108] [plan]

[0109] Those skilled in the art will understand that the above-described embodiments are specific examples of the following solutions.

[0110] (Item 1) A microfluidic device according to one embodiment is a plate-shaped microfluidic device used in a test in which a test solution containing a sample reacts with a reagent. The microfluidic device includes: an opening for receiving the test solution; a main flow path communicating with the opening; a plurality of microflow paths, each communicating with the main flow path; and a recovery section disposed in the main flow path at an outlet end opposite to the inlet end communicating with the opening, for recovering a portion of the test solution. The recovery section includes: a pool for storing the test solution discharged from the main flow path; a connecting flow path connecting the pool to the outlet end; and a protrusion disposed in the connecting flow path to receive the test solution discharged from the main flow path and to generate air bubbles that block the connecting flow path between the protrusion and the inner wall of the connecting flow path.

[0111] According to the microfluidic device described in item 1, by utilizing the air bubbles generated by setting protrusions, it is possible to prevent the backflow of the test liquid from the recovery section to the main flow path, resulting in the test liquid being able to remain in the recovery section.

[0112] (Item 2) In the microflow device described in Item 1, the connecting flow path includes an inclined flow path having an inclined surface that is inclined toward the outside of the connecting flow path. The inclination angle of the inclined surface relative to the flow path extending from the inclined surface is less than 90 degrees.

[0113] According to the microflow path device described in item 2, since the tilt angle is less than 90 degrees, it is possible to prevent the test liquid from remaining at the boundary between the tilted surface and the flow path extending from the tilted surface. That is, it is possible to prevent the test liquid from remaining in the connecting flow path, and as a result, it is possible to prevent the backflow of the test liquid from the recovery section to the main flow path.

[0114] (Item 3) In the microflow device described in Item 2, the surface opposite to the surface with the opening in the wall that constitutes each flow path is flat.

[0115] The microflow path device described in item 3 simplifies the flow path structure and makes it easy to manufacture the microflow path device.

[0116] (Item 4) In the microflow device described in Item 2 or Item 3, an inclined surface is formed on the side of the wall that forms the connecting flow path and has an opening.

[0117] According to the microflow path device described in item 4, it is possible to prevent the test liquid from remaining at the boundary between the inclined surface and the flow path extending from the inclined surface. That is, it is possible to prevent the test liquid from remaining in the connecting flow path, and as a result, it is possible to prevent the backflow of the test liquid from the recovery section to the main flow path.

[0118] (Item 5) The microflow path device according to any one of items 2 to 4, wherein the protrusion is disposed in the inclined flow path.

[0119] According to the microflow path device described in item 5, since the inclined flow path is a flow path with an enlarged cross-sectional area, protrusions can be easily provided.

[0120] (Item 6) In any one of the microfluidic devices described in items 1 to 5, the protrusion has a shape that tapers toward the tip of the outlet side end.

[0121] According to the microfluidic device described in item 6, it is possible to prevent the test liquid from remaining at the boundary between the protrusions and the protrusion mounting surfaces. That is, it is possible to prevent the test liquid from remaining in the connecting flow path, and as a result, it is possible to prevent the backflow of the test liquid from the recovery section to the main flow path.

[0122] (Item 7) In any one of items 1 to 6, the connecting flow path includes a tapered portion whose width increases from the outlet end toward the pool. The tapered angle of the tapered portion is less than 180 degrees.

[0123] According to the microflow path device described in item 7, it is possible to prevent the test liquid from remaining at the boundary between the cone and the flow path extending from the cone. That is, it is possible to prevent the test liquid from remaining in the connecting flow path, and as a result, it is possible to prevent the backflow of the test liquid from the recovery section to the main flow path.

[0124] The embodiments of the present invention have been described above, but it should be considered that the embodiments disclosed herein are illustrative rather than restrictive in all respects. The scope of the invention is set forth in the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A microfluidic device, a plate-shaped microfluidic device used in a test in which a test solution containing a sample reacts with a pharmaceutical agent, characterized in that, have: Open the container to receive the test solution; The main path is connected to the opening; Multiple microflow paths are connected to the main flow path, respectively; A recovery section, located at the outlet end opposite to the inlet end communicating with the opening in the main flow path, recovers a portion of the test solution. The recycling unit includes: A pool for storing the test solution discharged from the main flow path; Connect the flow path to connect the pool to the outlet end; A protrusion is disposed in the connecting flow path to receive the test liquid discharged from the main flow path and to generate air bubbles that block the connecting flow path between the protrusion and the inner wall of the connecting flow path.

2. The microfluidic device as described in claim 1, characterized in that, The connecting flow path has an inclined flow path with an inclined surface that slopes outwards towards the outside of the connecting flow path. The angle of inclination of the inclined surface relative to the flow path extending from the inclined surface is less than 90 degrees.

3. The microfluidic device as described in claim 2, characterized in that, In the wall that forms each flow path, the surface opposite to the surface where the opening is located is flat.

4. The microfluidic device as described in claim 2 or 3, characterized in that, The inclined surface is formed on the side of the wall that forms the connecting flow path, on the side where the opening is provided.

5. The microfluidic device as described in claim 2 or 3, characterized in that, The protrusion is disposed in the inclined flow path.

6. The microfluidic device as described in claim 1 or 2, characterized in that, The protrusion has a shape that tapers towards the tip of the outlet side end.

7. The microfluidic device according to any one of claims 1 to 3, characterized in that, The connecting flow path has a tapered portion whose flow path width increases from the outlet end toward the pool. The cone angle of the cone is less than 180 degrees.

8. The microfluidic device according to any one of claims 1 to 3, characterized in that, When viewed from a direction orthogonal to the surface in which the opening is provided, the protrusion has a size that forms a flow path between the protrusion and the inner wall of the connecting flow path.

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