A control valve and a centrifugal microfluidic chip

Abstract

The present invention belongs to the technical field of microfluidic chips, and discloses a control valve which is arranged on a microfluidic channel (2) of a microfluidic chip. The microfluidic chip comprises a chip body (1). The control valve comprises a valve cavity (3) and a reversible water absorption mechanism (4), and the reversible water absorption mechanism (4) is arranged in the valve cavity (3). Also disclosed is a centrifugal microfluidic chip, which comprises a chip body (1), a liquid inlet (7), a reaction chamber (8), and a microfluidic channel (2), and further comprises a control valve arranged between the liquid inlet (7) and the reaction chamber (8), and the control valve is the above-mentioned control valve. The present invention provides a control valve and a centrifugal microfluidic chip, which are simple to process, do not require complex treatment, can realize the step-by-step release of a solution by changing the centrifugal speed, and are convenient to use.

Description

Technical Field

[0001] The present invention relates to the technical field of microfluidic chips, and particularly to a control valve and a centrifugal microfluidic chip. Background Art

[0002] Microfluidics technology integrates basic operation units such as sample preparation, reaction, separation, and detection in the analysis processes of biology, chemistry, and medicine onto a chip at the micron scale, and automatically completes the entire analysis process. Due to its great potential in the fields of biology, chemistry, medicine, etc., it has developed into a brand-new research field that intersects multiple disciplines such as biology, chemistry, medicine, fluid, electronics, materials, and machinery. Due to the advantages of microfluidic chips such as small sample consumption, fast reaction time, high detection throughput, and good integration performance, they are increasingly being applied in fields such as portable detection.

[0003] Centrifugal microfluidic chips, that is, using centrifugal force as the driving force to achieve fluid flow and unit operations on the chip, thereby completing various biochemical reactions and detection processes, are a relatively popular product form at present. Its advantage lies in controlling the rotation of the chip through a centrifuge, avoiding the need for large driving devices such as injection pumps in planar chips, with simple and portable equipment, meeting the current trend of miniaturization of detection equipment.

[0004] Conventional biochemical reactions usually involve multiple fluids and multiple reaction steps. The addition and reaction of fluids require strict sequence and time, so it is necessary to build a control valve on the centrifugal chip to complete the above functions.

[0005] At present, the control valves on centrifugal chips are mainly divided into active and passive types. Among them, the active type requires additional control devices besides centrifugal force, while the passive type does not require additional control devices and only relies on centrifugal force. Since the active control valve needs to add control devices such as heating, cooling, and lighting, it increases the complexity and cost of the equipment. Most commercial products and academic research choose passive control valves. Currently, passive control valves mainly include capillary valves, hydrophilic-hydrophobic valves, structure-breaking valves, and some pneumatic valves. The above various control valves require high processing precision (capillary valves, pneumatic breaking valves) or additional processing means (hydrophilic-hydrophobic valves, structure-breaking valves). For complex biochemical reactions involving multiple fluids or multiple reaction steps, it is difficult to integrate multiple control valves on the same chip with the above control valves. For example, for capillary valves, as the capillary valve is far from the center of the chip, if a capillary valve needs to be used, the size of the capillary structure needs to be significantly reduced, which has exceeded the conventional processing limit. The processing process of hydrophilic-hydrophobic valves is difficult to precisely control. Therefore, a large margin is required for speed control. For example, a difference of 1500 rpm needs to be ensured between two hydrophobic valves to ensure the smooth implementation of sequential reactions, which greatly improves the requirements for the centrifuge. In addition, the introduction of hydrophilic-hydrophobic reagents may affect the reagent system of biochemical reactions. In short, the existing control valves on centrifugal chips cannot quickly and simply integrate multiple control valves and cannot meet the complex biochemical reaction process, so it is necessary to develop new control valves for supplementation.

[0006] Based on the above situation, it is necessary for us to design a control valve for a centrifugal microfluidic chip that can solve the above problems. Summary of the Invention

[0007] The purpose of the present invention is to provide a control valve that is simple to process, does not require complex treatment, can realize the step-by-step release of solutions by changing the centrifugal speed, and is convenient to use.

[0008] Another purpose of the present invention is to provide a centrifugal microfluidic chip that is simple to process, does not require complex treatment, can realize the step-by-step release of solutions by changing the centrifugal speed, and is convenient to use.

[0009] To achieve this purpose, the present invention adopts the following technical solutions:

[0010] On the one hand, a control valve is provided, which is arranged on the microfluidic channel of the microfluidic chip. The microfluidic chip includes a chip body. The control valve includes a valve cavity and a reversible water absorption mechanism, and the reversible water absorption mechanism is arranged in the valve cavity.

[0011] Specifically, the reversible water absorption mechanism is made of a porous material with water absorption and water release functions. The reversible water absorption mechanism is filled in the valve cavity. After the reversible water absorption mechanism absorbs water, under the action of centrifugal force, the solution can be released again. Moreover, by changing the centrifugal speed, the step-by-step release of the solution can be achieved, playing the role of controlling the valve.

[0012] As a preferred technical solution, the reversible water absorption mechanism is encapsulated in an anti-deformation packaging film.

[0013] Specifically, the anti-deformation packaging film is a porous water-permeable film. Using the anti-deformation packaging film can, to a certain extent, limit the deformation of the reversible water absorption mechanism and avoid affecting the chip sealing process. The anti-deformation packaging film is required to be a film that does not affect biochemical reactions and water absorption capacity.

[0014] As a preferred technical solution, the reversible water absorption mechanism is one or more of sponge, foam, and water-absorbing fiber.

[0015] Specifically, the reversible water absorption mechanism is required to have the following properties: the reversible water absorption mechanism does not adsorb or adsorbs less of the active ingredients (such as proteins, etc.) in the biochemical reagent. For example, the reversible water absorption mechanism can be subjected to a sealing treatment to inhibit the adsorption of proteins in the reagent by the reversible water absorption mechanism; the pore sizes of the porous material of the reversible water absorption mechanism are as uniform as possible. Under the same conditions, the adsorption and release amounts of the reagent can be reproduced; after the reversible water absorption mechanism absorbs water, its volume does not change significantly. Different from the porous material of chemical adsorption, after the porous material of chemical adsorption is saturated with water, its volume can be enlarged by dozens of times.

[0016] As a preferred technical solution, the anti-deformation packaging film is gauze.

[0017] As a preferred technical solution, the chip body includes an upper chip plate and a lower chip plate, and the microfluidic channel and the valve cavity are arranged between the upper chip plate and the lower chip plate.

[0018] Specifically, the material of the chip body includes silicon wafers, glass, PDMS, metals, and hard polymer materials represented by PMMA / PC / PS, etc. The processing means of the chip body can include processing means such as photolithography, soft injection molding, wet etching, laser processing, numerical control machine tools, and injection molding.

[0019] Since in the processing of the control valve of the present invention, it is necessary to place the reversible water absorption mechanism in the valve cavity, and then seal the upper chip plate and the lower chip plate by conventional sealing means, and the conventional sealing means include means such as gluing, thermocompression sealing, ultrasonic sealing, and laser sealing.

[0020] As a preferred technical solution, a sealing mechanism is provided on the upper chip board and the lower chip board, and the sealing mechanism is located outside the edge of the valve cavity.

[0021] Specifically, since the reversible water absorption mechanism is compressible and prone to expansion, when the reversible water absorption mechanism is placed in the valve cavity, it is easy for the reversible water absorption mechanism to protrude in the valve cavity, resulting in a gap easily appearing between the upper chip board and the lower chip board during the sealing process. The existence of this gap may cause the failure of the control valve, that is, the liquid will flow into the next structure of the chip body through this gap instead of passing through the reversible water absorption mechanism. Setting the sealing mechanism outside the edge of the valve cavity can effectively limit the reversible water absorption mechanism in the valve cavity during assembly, avoiding a large amount of the reversible water absorption mechanism remaining between the upper chip board and the lower chip board due to the easily deformable characteristics of the reversible water absorption mechanism, forming a gap and affecting the sealing effect, resulting in the failure of the control valve of the present invention.

[0022] As a preferred technical solution, the sealing mechanism includes a cooperating sealing boss and a sealing groove;

[0023] The sealing boss is provided on the upper chip board, and the sealing groove is provided on the lower chip board;

[0024] Alternatively, the sealing boss is provided on the lower chip board, and the sealing groove is provided on the upper chip board.

[0025] Specifically, this sealing mechanism can not only serve as the sealing line and sealing groove for the ultrasonic sealing method, but also play the role of restricting the position of the reversible water absorption mechanism when using other sealing methods, avoiding the gap between the upper chip board and the lower chip board caused by the reversible water absorption mechanism being squeezed during the chip sealing process and affecting the sealing effect.

[0026] As a preferred technical solution, the cross-sectional shape of the sealing boss is trapezoidal, and the cross-sectional shape of the sealing groove is trapezoidal or rectangular.

[0027] Specifically, the cross-sectional area of the sealing boss is larger than that of the sealing groove, which can ensure the sealing and assembly effects. If ultrasonic sealing is used, the sealing boss structure serves as the energy guiding rib, and the sealing groove structure serves as the sealing groove to achieve sealing; if adhesive bonding is used, the area between the sealing groove and the valve cavity can play a sufficient sealing role; if laser sealing is used, the area between the sealing groove and the valve cavity is sufficient for laser sealing the upper chip board and the lower chip board to play a sealing role.

[0028] Another invention provides a centrifugal microfluidic chip, which includes a chip body, a liquid inlet, a reaction chamber, and a microfluidic channel. It further includes a control valve disposed between the liquid inlet and the reaction chamber, and the control valve is the above-mentioned control valve.

[0029] The beneficial effects of the present invention are as follows: A control valve is provided, which is simple to process and does not require complex treatment. The step-by-step release of the solution can be achieved by changing the centrifugal speed, and it is convenient to use. This control valve functions as a control valve and can be used alone or in combination with other conventional control valves to complete complex biochemical reactions on the centrifugal microfluidic chip. At the same time, a centrifugal microfluidic chip is provided, which is simple to process and does not require complex treatment. The step-by-step release of the solution can be achieved by changing the centrifugal speed, and it is convenient to use. Description of the Drawings

[0030] Figure 1 It is a schematic structural diagram of Embodiment 1 of the present invention;

[0031] Figure 2a It is a schematic side view of the chip body before sealing in Embodiment 1 of the present invention;

[0032] Figure 2b It is a schematic side view of the chip body after sealing in Embodiment 1 of the present invention;

[0033] Figure 3 It is a schematic side view of Embodiment 2 of the present invention;

[0034] Figure 4 It is a schematic diagram of the sealing mechanism in Embodiment 2 of the present invention;

[0035] Figure 5 It is a schematic structural diagram of Embodiment 3 of the present invention;

[0036] Figure 6 It is a schematic structural diagram of Embodiment 4 of the present invention.

[0037] Wherein:

[0038] Chip body 1, chip upper plate 11, chip lower plate 12, microfluidic channel 2, valve cavity 3, reversible water absorption mechanism 4, sealing boss 5, sealing groove 6, liquid inlet 7, reaction chamber 8, exhaust port 9, liquid storage pool 10, chip fixing hole 13;

[0039] Washing pool 80;

[0040] Sample injection port 14, first magnetic bead transfer channel 15, second magnetic bead transfer channel 16, hydrophobic valve 17, gap 18;

[0041] First microfluidic channel 21, second microfluidic channel 22, third microfluidic channel 23;

[0042] The first valve cavity 31, the second valve cavity 32, the third valve cavity 33;

[0043] The first liquid inlet 71, the second liquid inlet 72, the third liquid inlet 73;

[0044] The first reaction chamber 81, the second reaction chamber 82, the third reaction chamber 83;

[0045] The first exhaust port 91, the second exhaust port 92, the third exhaust port 93;

[0046] The first liquid storage tank 101, the second liquid storage tank 102, the third liquid storage tank 103. Detailed implementation mode

[0047] To have a further understanding and recognition of the structural features and achieved effects of the present invention, the following is a detailed description with preferred embodiments and accompanying drawings:

[0048] Embodiment 1:

[0049] As Figure 1 shown, the present invention provides a control valve disposed on the microfluidic channel 2 of a microfluidic chip. The microfluidic chip includes a chip body 1. As an improvement of the present invention, the control valve includes a valve cavity 3 and a reversible water absorption mechanism 4, and the reversible water absorption mechanism 4 is disposed within the valve cavity 3.

[0050] As a further improvement of the present invention, the reversible water absorption mechanism 4 is encapsulated within a deformation-proof packaging film (not shown in the figure). The reversible water absorption mechanism 4 is one or more of sponge, foam, and water-absorbing fiber. The deformation-proof packaging film is gauze. As Figure 2a and 2b shown, the chip body 1 includes a chip upper plate 11 and a chip lower plate 12, and the microfluidic channel 2 and the valve cavity 3 are disposed between the chip upper plate 11 and the chip lower plate 12.

[0051] The present invention also provides a centrifugal microfluidic chip, including a chip body 1, a liquid inlet 7, a reaction chamber 8, a microfluidic channel 2. An exhaust port 9 is disposed on one side of the liquid inlet 7, and both the liquid inlet 7 and the exhaust port 9 are in communication with a liquid storage tank 10. A chip fixing hole 13 is disposed at the center of the chip body 1. The chip also includes a control valve disposed between the liquid inlet 7 and the reaction chamber 8, and the control valve is the above-mentioned control valve.

[0052] During the assembly process, first, an appropriate amount of the reversible water absorption mechanism (0.2 - 20 g) is encapsulated within the gauze to prevent the reversible water absorption mechanism from being too fluffy and affecting the chip sealing. The amount of the reversible water absorption mechanism is selected according to the amount of reagents required for the biochemical reaction. Since the water absorption and water release data of a specific reversible water absorption mechanism can be determined, the amount of the reversible water absorption mechanism can be determined based on the material type and the amount of reagents of the reversible water absorption mechanism.

[0053] The above anti-deformation packaging film is not limited to gauze, and any film that does not affect the biochemical reaction and the water absorption of the reagent can be used. The purpose is to limit the deformation of the porous material to a certain extent and avoid affecting the chip sealing process.

[0054] Place the reversibly water-absorbing mechanism wrapped with gauze in the valve cavity, and then seal the upper chip plate and the lower chip plate together by conventional means.

[0055] After the above centrifugal microfluidic chip with a control valve structure is processed, during use, first fix the chip body 1 on the centrifuge, then add the test solution into the liquid storage pool 10 through the liquid inlet 7, and then control the centrifuge to start rotating. The reagent enters the control valve. Due to the action of the reversibly water-absorbing mechanism 4, at a certain rotational speed (ω), the solution does not release from the control valve. Only after the rotational speed of the centrifuge exceeds ωc (the turning speed), the solution begins to release from the control valve, thus playing the role of a control valve.

[0056] By changing the type of the reversibly water-absorbing mechanism and the distance between the control valve and the center of the chip (different distances result in different centrifugal forces), ωc is in the range of 400 - 3000 rpm, which can meet the requirements of the centrifugal microfluidic chip for the control valve.

[0057] In addition, when the reversibly water-absorbing mechanism selects a highly water-absorbing material, the water release amount is proportional to the rotational speed and time. Using this result, while increasing the rotational speed and holding time step by step, the liquid in the control valve can be released step by step, which is very helpful for processes such as multiple cleaning of biochemical reactions.

[0058] Through experimental comparison, it is found that the water release and water absorption ratio of the control valve of the present invention is as high as over 95% (3000 rpm, 45 s). Further increasing the rotational speed and time can continue to increase this ratio.

[0059] Example Two:

[0060] The difference between this example and Example One is as follows:

[0061] As Figure 3 shown, a sealing mechanism is provided on the upper chip plate 11 and the lower chip plate 12, and the sealing mechanism is located outside the edge of the valve cavity 3.

[0062] The sealing mechanism includes a cooperating sealing boss 5 and a sealing groove 6; the sealing boss 5 is provided on the upper chip plate 11, and the sealing groove 6 is provided on the lower chip plate 12. It should be noted that the sealing boss 5 can also be provided on the lower chip plate 12, and the sealing groove 6 is provided on the upper chip plate 11.

[0063] The cross-sectional shape of the sealing boss 5 is trapezoidal, and the cross-sectional shape of the sealing groove 6 is trapezoidal or rectangular.

[0064] When there is no sealing mechanism between the chip upper plate 11 and the chip lower plate 12, as Figure 2a and 2b shown, when the reversible water absorption mechanism 4 is placed in the valve cavity 3, the reversible water absorption mechanism 4 may protrude in the valve cavity 3, resulting in a gap 18 between the chip upper plate 11 and the chip lower plate 12 during the sealing process. The existence of this gap 18 may cause the failure of the control valve, that is, the liquid will flow into the next structure of the chip body 1 through this gap 18 instead of passing through the reversible water absorption mechanism 4. Therefore, setting a sealing mechanism outside the edge of the valve cavity 3 can effectively limit the reversible water absorption mechanism 4 in the valve cavity 3 during assembly, avoiding a large amount of the reversible water absorption mechanism 4 being left between the chip upper plate 11 and the chip lower plate 12 due to the easily deformable characteristics of the reversible water absorption mechanism 4, forming a gap and affecting the sealing effect, resulting in the failure of the control valve of the present invention.

[0065] The dimensional requirements of the sealing boss 5 and the sealing groove 6 are as Figure 4 shown. To ensure the sealing and assembly effects and considering the difficulty of processing, it is required that W1 > W3 > W2 and W3 ≥ W4. According to the processing ability and the chip material, the dimensional range of W1 - W4 is between 0.5 - 10 mm, and W5 is set to 0.4 - 2 mm according to the processing ability. To ensure the sealing and assembly effects and considering the difficulty of processing, the dimensions of H1 and H2 are between 0.2 - 1.0 mm, and it is required that H3 ≥ H4. It is necessary to ensure that the cross-sectional area of the sealing boss 5 is larger than the cross-sectional area of the sealing groove 6, so as to ensure that the sealing boss 5 can seal the sealing groove 6 during ultrasonic sealing. If ultrasonic sealing is used, the sealing boss 5 acts as a energy guiding rib and the sealing groove 6 acts as a sealing groove to achieve sealing; if an adhesive method is used, the area of the W5 part can play a role in sufficient sealing; if laser seam sealing is used, the area of W5 is large enough, and the width should be above 0.3 mm to meet the area requirement of laser sealing and play a sealing role.

[0066] Embodiment 3:

[0067] This embodiment takes the magnetic bead cleaning in the chemiluminescence reaction process as an example. Generally, the chemiluminescence kit requires cleaning the magnetic beads 2 - 3 times. Through the device of the present invention, after adding a cleaning solution once, the cleaning solution can be released quantitatively one by one to realize the process of magnetic bead cleaning.

[0068] Considering the reagent ratio of chemiluminescence and the characteristics of the centrifugal microfluidic chip, in this embodiment, a total of 60 μL of cleaning solution is released in three times.

[0069] As Figure 5 shown, the centrifugal microfluidic chip structure adopted in this embodiment is the same as the centrifugal microfluidic chip structure in Embodiment 1 or Embodiment 2, and the reaction cavity is the cleaning pool 80.

[0070] The reversible water absorption mechanism selects the highly water-absorbent and moisture-absorbent fiber "Hygra" porous material developed by Unitika Ltd. of Japan. According to the test results, 20-25 g of the above material is sealed in the valve cavity of the centrifugal microfluidic chip.

[0071] The usage process is as follows:

[0072] 65 μL of cleaning solution is added to the liquid inlet 1 of the centrifugal microfluidic chip through a pipette, and then the cleaning solution is completely released into the valve cavity 3 at a rotational speed of 300 rpm. At this time, all the cleaning solution is stored in the valve cavity 3.

[0073] The rotational speed is increased to 500-800 rpm and maintained for 3-6 s, and 20 μL of the cleaning solution is released into the cleaning pool 80.

[0074] Next, the rotational speed is increased to 1200-1400 rpm and maintained for 3-6 s, and 20 μL of the cleaning solution is released into the cleaning pool 80.

[0075] Finally, the rotational speed is increased to above 1800 rpm and maintained for more than 5 s, and 20 μL of the cleaning solution is released into the cleaning pool 80.

[0076] The present invention can perform the functions of liquid storage, control valve, and multi-stage release, and is particularly suitable for application fields such as chemiluminescence and molecular diagnosis that involve multiple solution reaction systems and steps, which is beneficial to the application of the centrifugal microfluidic chip in the field of biochemical detection.

[0077] Example 4:

[0078] Taking the magnetic bead method double-antibody sandwich chemiluminescence system as an example, this example realizes the detection of the content of alpha-fetoprotein in serum by chemiluminescence method.

[0079] The centrifugal microfluidic chip of this example includes the control valve structure in Example 1 or Example 2, and its specific structure is as Figure 6 shown, including a chip body 1. At the center of the chip body 1 is a chip fixing hole 13. Three microfluidic channels are arranged in the chip body 1, namely a first microfluidic channel 21, a second microfluidic channel 22, and a third microfluidic channel 23;

[0080] On the first microfluidic channel 21, a first liquid storage pool 101, a first valve cavity 31, and a first reaction cavity 81 are sequentially arranged from the front end to the end. A first liquid inlet 71 and a first exhaust port 91 are arranged on the first liquid storage pool 101;

[0081] On the second microfluidic channel 22, a second liquid storage pool 102, a second valve cavity 32, and a second reaction cavity 82 are sequentially arranged from the front end to the end. A second liquid inlet 72 and a second exhaust port 92 are arranged on the second liquid storage pool 102;

[0082] On the third microfluidic channel 23, a third liquid storage pool 103, a third valve cavity 33, a hydrophobic valve 17, and a third reaction cavity 83 are sequentially arranged from the front end to the end. A third liquid inlet 73 and a third exhaust port 93 are provided on the third liquid storage pool 103;

[0083] The distance between the first valve cavity 31 and the center of the chip body 1 is less than the distance between the second valve cavity 32 and the center of the chip body 1, and the distance between the second valve cavity 32 and the center of the chip body 1 is less than the distance between the third valve cavity 33 and the center of the chip body 1;

[0084] A sample injection port 14 is provided on the first reaction cavity 81. The first reaction cavity 81 is communicated with the second reaction cavity 82 through a first magnetic bead transfer channel 15, and the second reaction cavity 82 is communicated with the third reaction cavity 83 through a second magnetic bead transfer channel 16. Reaction cavity exhaust ports are provided on the first reaction cavity 81, the second reaction cavity 82, and the third reaction cavity 83;

[0085] Reversible water absorption mechanisms are fixedly filled in the first valve cavity 31, the second valve cavity 32, and the third valve cavity 33.

[0086] The reversible water absorption mechanism in this embodiment selects the highly water-absorbent and moisture-absorbent fiber "Hygra" porous material developed by Unitika Ltd. of Japan.

[0087] The specific implementation steps are as follows:

[0088] Add an appropriate amount of serum sample and magnetic bead solution into the reaction cavity on the chip through the sample injection port 14;

[0089] Add the antibody solution into the chip body 1 through the first liquid inlet 71;

[0090] Add the cleaning solution into the chip body 1 through the second liquid inlet 72;

[0091] Add the light-emitting substrate solution into the chip body 1 through the third liquid inlet 73;

[0092] Fix the chip on the centrifuge through the chip fixing hole 13;

[0093] Control the centrifugal microfluidic chip to rotate at a first rotation speed (ω1) through the centrifuge, so that the antibody solution, the cleaning solution, and the light-emitting substrate solution enter the first valve cavity 31, the second valve cavity 32, and the third valve cavity 33 respectively. ω1 is between 50 - 300 rpm, depending on the solution volume, the amount of water-absorbent fiber, and the distance from each valve cavity to the center of the chip body 1;

[0094] The centrifuge is used to control the centrifugal microfluidic chip to rotate at a second rotational speed (ω2, ω2 > ω1). The antibody solution in the first valve chamber 31 is gradually released into the first reaction chamber 81. The magnetic beads are controlled to move in the first reaction chamber 81 by oscillating the chip clockwise / counterclockwise or using a magnet, so as to form a double-antibody sandwich structure.

[0095] The magnet is used to control the magnetic beads to enter the second reaction chamber 82 through the first magnetic bead transfer channel 15.

[0096] The centrifuge is used to control the centrifugal microfluidic chip to rotate at a third rotational speed (ω3, ω3 > ω2). The cleaning solution in the second valve chamber 32 is gradually released into the second reaction chamber 82. The magnetic beads are controlled to move in the second reaction chamber 82 by oscillating the chip clockwise / counterclockwise or using a magnet, which can better achieve the cleaning of the magnetic beads. In addition, the cleaning solution can be released step by step by gradually increasing the rotational speed. For example, a part of the cleaning solution is released at ω3-1, and all the cleaning solution in the second valve chamber 32 is released at ω3-2, so as to achieve the effect of step-by-step cleaning, where ω3-2 > ω3-1.

[0097] The magnet is used to control the magnetic beads to enter the third reaction chamber 83 through the second magnetic bead transfer channel 16.

[0098] The centrifuge is used to control the centrifugal microfluidic chip to rotate at a fourth rotational speed (ω4, ω4 > ω3). The luminescent substrate solution in the third valve chamber 33 is gradually released into the third reaction chamber 83. The double-antibody sandwich structure on the magnetic beads reacts with the luminescent substrate to release photons, which can be detected by a detection device, so as to detect the content of alpha-fetoprotein in the sample to be tested.

[0099] In addition, since the rotational speed ω2 or ω3 may be relatively high during the process of releasing the solution from the first valve chamber 31 and the second valve chamber 32, a hydrophobic valve 17 is added at the rear end of the third valve chamber 33 to ensure that the solution in the third valve chamber 33 will not be released into the third reaction chamber 83 when rotating at the rotational speed ω2 or ω3.

[0100] ω1 is between 50 - 300 rpm, and the magnitude of the release rotational speeds ω2 < ω3 < ω4 is related to the distance from the corresponding valve chamber to the center of the circle.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A control valve is disposed on a microfluidic channel (2) of a microfluidic chip, and the microfluidic chip includes a chip body (1). Characterized in that the control valve includes a valve cavity (3) and a reversible water absorption mechanism (4), and the reversible water absorption mechanism (4) is disposed in the valve cavity (3); the reversible water absorption mechanism (4) is encapsulated in gauze; the reversible water absorption mechanism (4) is one or more of sponge, foam, and water absorption fiber; the chip body (1) includes a chip upper plate (11) and a chip lower plate (12), and the microfluidic channel (2) and the valve cavity (3) are disposed between the chip upper plate (11) and the chip lower plate (12); sealing mechanisms are disposed on the chip upper plate (11) and the chip lower plate (12), and the sealing mechanisms are located outside the edge of the valve cavity (3); the sealing mechanisms include a matching sealing boss (5) and a sealing groove (6); the sealing boss (5) is disposed on the chip upper plate (11), and the sealing groove (6) is disposed on the chip lower plate (12); or, the sealing boss (5) is disposed on the chip lower plate (12), and the sealing groove (6) is disposed on the chip upper plate (11).

2. A control valve according to claim 1, Characterized in that the cross-sectional shape of the sealing boss (5) is trapezoidal, and the cross-sectional shape of the sealing groove (6) is trapezoidal or rectangular.

3. A centrifugal microfluidic chip includes a chip body (1), a liquid inlet (7), a reaction chamber (8), and a microfluidic channel (2). Characterized in that it further includes a control valve disposed between the liquid inlet (7) and the reaction chamber (8), and the control valve is the control valve according to any one of claims 1 to 2.

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