A microfluidic chip with a flow channel switching valve

Abstract

The present invention belongs to the field of immunology and detection technology, and specifically relates to a microfluidic chip with a flow channel switching valve. The chip comprises a cleaning liquid flow channel, a buffer flow channel, a waste liquid flow channel, a first mixing flow channel, a second mixing flow channel, a flow channel switching valve, a detection zone, a first waste liquid tank, a second waste liquid tank, a sample well, an immunomagnetic bead injection device, and a fluorescent antibody injection device. The cleaning liquid flow channel, the buffer flow channel, the waste liquid flow channel, the first mixing flow channel, and the second mixing flow channel are respectively connected to the flow channel switching valve, the second end of the second mixing flow channel is connected to the inlet of the detection zone, and the outlet of the detection zone is connected to the second waste liquid tank. The height of the detection zone is less than the spacing between adjacent magnetic bead, sample, and antibody mixed microspheres. Using the microfluidic chip of the present invention for antigen concentration detection can simplify the operating steps of the entire process, improve the efficiency of antigen concentration detection, and greatly save the production cost of the microfluidic chip.

Description

Technical Field

[0001] The present invention belongs to the field of immunity and detection technology, and particularly relates to a microfluidic chip with a flow channel switching valve. Background Art

[0002] The application of protein detection technologies such as immunohistochemistry and ELISA is very extensive, and it has realized the detection of thousands of protein biomarkers. Single-molecule immunoassay technology has higher detection sensitivity and wider detection range. One of the core technologies in single-molecule immunoassay is antigen conjugate coplanar technology, which requires antigen conjugates such as magnetic bead solutions to be sucked into the detection area by positive pressure or negative pressure, and it is necessary to ensure that all particles are coplanar and evenly dispersed. The US patent application publication number US20100075407A1 discloses a chip that uses centrifugal method to inject magnetic bead solution into the detection area. Microwells are set in the area, and each particle needs to fall into a microwell to achieve coplanarity and uniform dispersion of particles. The Chinese invention patent specification with application publication number CN111735964A discloses a magnetic bead tile chip that uses positive pressure to inject magnetic beads and sets probes to graft magnetic beads in the detection area. The coplanarity and uniformity of the probes ensure the coplanarity and uniformity of the magnetic beads. In these two chips, the production process of the chip is complicated due to the setting of micro-wells or probes. Correspondingly, the precision requirements of its production equipment are also high, the cost is high, and during the detection process, the magnetic beads have a low hole-falling rate and binding rate, and need to be rinsed with oil layers or other reagents. The steps are cumbersome and wasteful of reagents. The Chinese utility model patent specification with authorization announcement number CN217910491U discloses a magnetic bead tile chip, which uses positive pressure to inject magnetic beads and designs the depth of the detection area to be small enough to ensure the coplanarity and uniformity of the magnetic beads. However, the pretreatment process needs to be carried out outside the chip. The whole process is time-consuming and complicated, and it is not easy to avoid aerosol contamination. Summary of the Invention

[0003] The purpose of the present invention is to provide a microfluidic chip with a flow channel switching valve to solve the technical problem that the existing microfluidic chip has a low hole-falling rate and needs to be flushed with an oil layer or other reagents, which is cumbersome and wastes reagents. It also solves the technical problem that when detecting antigen concentration, the process of generating magnetic bead sample antibody mixed microspheres and cleaning the mixed microspheres is time-consuming and complicated and may cause aerosol pollution.

[0004] In order to solve the above technical problems, the present invention provides a microfluidic chip with a flow channel switching valve, comprising a cleaning liquid flow channel, a buffer flow channel, a waste liquid flow channel, a first mixing flow channel, a second mixing flow channel and a flow channel switching valve; one end of the cleaning liquid flow channel, one end of the buffer flow channel, one end of the waste liquid flow channel, one end of the first mixing flow channel and one end of the second mixing flow channel are respectively connected to the flow channel switching valve, the other end of the cleaning liquid flow channel is connected to a cleaning liquid injection device, the other end of the buffer flow channel is connected to a buffer injection device, the other end of the waste liquid flow channel is connected to a first waste liquid tank, and the first mixing channel is connected to a second mixing channel. The other end of the confluence channel is connected to the sample hole, the immunomagnetic bead injection device and the fluorescent antibody injection device, the second end of the second mixing channel is connected to the inlet of the detection area, and the outlet of the detection area is connected to the second waste liquid bin; the height of the detection area is less than the spacing between adjacent magnetic bead sample antibody mixed microspheres; the channel switching valve has a valve cavity and has four working states, in the first state, the cleaning liquid flow channel is connected to the waste liquid flow channel through the valve cavity, in the second state, the buffer flow channel is connected to the second mixing flow channel through the valve cavity, in the third state, the first mixing flow channel is connected to the air hole connecting pipe through the valve cavity; in the fourth state, any two flow channels are not connected.

[0005] The beneficial effects are as follows: since the height of the detection zone is less than the spacing between adjacent magnetic bead sample antibody mixed microspheres, the magnetic beads can be automatically flattened in a focal plane, which can avoid the problem of mixed microspheres overlapping up and down in the detection zone and affecting the counting. There is no need to set multiple microwells in the chip and drop the mixed microspheres into them, and there is no need to use oil layers or other reagents to flush the mixed microspheres after they enter the detection zone; the flow channel switching valve has a valve cavity, which can serve as a double antibody sandwich incubation area and a position for washing excess microspheres; in the third state, the mixed microspheres in the first mixing flow channel can be allowed to enter the valve cavity for incubation; in the first state, the incubated mixed microspheres can be washed with a cleaning liquid, and the waste liquid can be flowed into the waste liquid tank through the waste liquid pipeline; after the cleaning is completed, the second state is switched to inject a buffer solution into the valve cavity to flush the mixed microspheres into the detection zone through the second mixing flow channel for counting. Using the microfluidic chip of the present invention for antigen concentration detection can make the operating steps of the entire process simpler, improve the efficiency of antigen concentration detection, and greatly save the production cost of the microfluidic chip.

[0006] Preferably, the flow channel switching valve includes a cylindrical valve body and a torque valve slot fixedly connected to the valve body for driving the valve body to rotate, the valve cavity is located inside the valve body, and the outer surface of the valve body is slidingly and sealingly connected to the flow channel openings of the pore connecting pipe, the cleaning liquid flow channel, the buffer flow channel, the waste liquid flow channel, the first mixing flow channel and the second mixing flow channel, respectively. The valve body is respectively provided with a first valve port for connecting the cleaning liquid flow channel and the valve cavity or connecting the dilution liquid flow channel and the valve cavity, a second valve port for connecting the second mixing flow channel and the valve cavity or connecting the waste liquid flow channel and the valve cavity, a third valve port for connecting the first mixing flow channel and the valve cavity, and a fourth valve port for connecting the valve cavity and the pore connecting pipe; and when the first valve port is located in a position connected to the cleaning liquid flow channel, the second valve port is located in a position connected to the waste liquid flow channel; when the first valve port is located in a position connected to the buffer flow channel, the second valve port is located in a position connected to the second mixing flow channel; when the third valve port is located in a position connected to the first mixing flow channel, the fourth valve port is located in a position connected to the pore connecting pipe.

[0007] Its beneficial effects are: by setting a valve slot and inserting an external column, the working state of the flow channel switching valve can be easily switched; by setting a gas connecting pipe, the valve cavity can be connected to the external atmosphere, making it easier for the mixed solution in the first mixing flow channel to enter the valve cavity for incubation.

[0008] Preferably, the other end of the first mixing channel is also connected to a gas injection device.

[0009] The beneficial effect is that by connecting the first mixing flow channel to the gas injection device, the liquid in the first mixing flow channel can be flowed into the valve cavity by injecting gas into the first mixing flow channel using gas pressure.

[0010] Preferably, it further comprises a valve column fixedly connected to the top of the valve body, and the torque valve groove is opened inside the valve column.

[0011] Preferably, the first valve port, the second valve port, the third valve port and the fourth valve port are all opened on the side of the valve body or the first valve port and the third valve port are opened on the top of the valve body, and the second valve port and the fourth valve port are opened at the bottom of the valve body.

[0012] Preferably, the gas injection device, the cleaning liquid injection device, the buffer injection device, the immunomagnetic bead injection device and the fluorescent antibody injection device all use vesicles, and a vesicle puncture needle is provided at the bottom of the vesicles.

[0013] Preferably, the microfluidic chip is formed by stacking at least two layers of plates, adjacent plates are sealed and fitted together, and the cleaning liquid flow channel, buffer flow channel, waste liquid flow channel, first mixing flow channel and second mixing flow channel are all opened on the plates.

[0014] Preferably, a sealing strip interface for installing a sealing strip is provided on the outermost plate, and the sealing strip is used to prevent liquid on the contact surface between the valve body of the channel switching valve and the channel opening from leaking to the outside of the microfluidic chip.

[0015] Preferably, the microfluidic chip is composed of four layers of first layer boards, second layer boards, third layer boards and fourth layer boards stacked in sequence, wherein the first layer is provided with positioning holes, exhaust holes, sealing strip interfaces, sample holes and five liquid capsule mounting holes, the second layer is provided with positioning holes, gas connecting pipes, valve pits for installing flow channel switching valves and five liquid capsule mounting holes, the third layer is provided with positioning holes, first mixing flow channels, second mixing flow channels, valve pits for installing flow channel switching valves, cleaning liquid flow channels, buffer flow channels, the upper half of the waste liquid flow channels, the detection area, the upper half of the first waste liquid bin and the upper half of the second waste liquid bin, the fourth layer is provided with positioning holes, the second part of the waste liquid flow channels, the lower half of the first waste liquid bin and the lower half of the second waste liquid bin.

[0016] Preferably, the microfluidic chip is composed of four layers of first layer boards, second layer boards, third layer boards and fourth layer boards stacked in sequence, wherein the first layer is provided with positioning holes, exhaust holes, valve holes, sample holes and five liquid capsule mounting holes, the second layer is provided with positioning holes, valve holes, a first mixing flow channel, a cleaning liquid flow channel, a buffer flow channel and five liquid capsule mounting holes, the third layer is provided with valve pits, positioning holes, the upper half of the waste liquid flow channel, the second mixing flow channel, the detection area, the upper half of the first waste liquid bin and the upper half of the second waste liquid bin, and the fourth layer is provided with positioning holes, the lower half of the waste liquid flow channel, the lower half of the first waste liquid bin and the lower half of the second waste liquid bin. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a bottom view of the flow channel switching valve of the first structure;

[0018] Figure 2 This is a three-dimensional diagram of the flow channel switching valve of the first structure;

[0019] Figure 3 Schematic diagram of the valve cavity structure of the flow channel switching valve of the first structure;

[0020] Figure 4 This is a schematic diagram of the layered structure of the microfluidic chip of the first structure A;

[0021] Figure 5 This is a schematic diagram of the layered structure of the microfluidic chip of the first structure B;

[0022] Figure 6 is a three-dimensional diagram of the flow channel switching valve of the second structure;

[0023] Figure 71 is a top view of the flow channel switching valve of the second structure;

[0024] Figure 8 This is a schematic diagram of the layered structure of the microfluidic chip of the second structure A;

[0025] Figure 9 This is a schematic diagram B of the layered structure of the microfluidic chip of the second structure.

[0026] Explanation of the figure marks: 1 is the torque valve slot; 2 is the valve column; 3 is the valve cavity; 4 is the first valve port; 5 is the second valve port; 6 is the third valve port; 7 is the fourth valve port; 8 is the cleaning liquid vesicle; 9 is the buffer vesicle; 10 is the immunomagnetic bead vesicle; 11 is the empty vesicle; 12 is the fluorescent antibody vesicle; 13 is the positioning hole; 14 is the exhaust hole; 15 is the sealing strip interface; 16 is the liquid capsule installation hole; 17 is the sample hole; 18 is the gas connecting pipe; 19 is the flow channel switching valve; 20 is the liquid capsule puncture needle; 21 is the waste liquid flow channel; 22 is the first waste liquid tank; 23 is the second waste liquid tank; 24 is the first mixing flow channel; 25 is the second mixing flow channel; 26 is the cleaning liquid flow channel; 27 is the buffer flow channel; 28 is the sealing strip; 29 is the detection area; 30 is the valve pit. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0028] Example 1 of a microfluidic chip with a flow channel switching valve:

[0029] like Figures 1 to 3As shown, the flow channel switching valve of this embodiment includes a cylindrical valve body and a valve column 2 fixedly connected to the valve body, a torque valve groove 1 for driving the valve body to rotate is provided on the valve column 2, the valve cavity 3 is located inside the valve body, and the outer surface of the valve body is used for sliding and sealing connection with the flow channel openings of the air hole connecting pipe 18, the cleaning liquid flow channel 26, the buffer flow channel 27, the waste liquid flow channel 21, the first mixing flow channel 24 and the second mixing flow channel 25 respectively, and the valve body is provided with a first valve port 4 for connecting the cleaning liquid flow channel 26 and the valve cavity 3 or connecting the diluent flow channel and the valve cavity 3, a valve port 4 for connecting the second mixing flow channel 25 and the valve cavity 3 or connecting the waste liquid flow channel The first valve port 4, the second valve port 5, the third valve port 6, the fourth valve port 7, the fourth valve port 7, the fourth valve port 7, and the fourth valve port 18 are all located on the side of the valve body. The size of each valve port is adapted to the size of the flow channel port to which it is connected. The first valve port 4, the second valve port 5, the third valve port 6, the fourth valve port 7, and the fourth valve port 7 are all located on the side of the valve body.

[0030] By setting a valve slot and inserting an external column, the working state of the flow channel switching valve 19 can be easily switched; by setting a gas connecting pipe, the valve cavity 3 can be connected to the external atmosphere, so that the mixed solution in the first mixing channel 24 can enter the valve cavity 3 for incubation.

[0031] like Figure 4 and Figure 5As shown, the microfluidic chip with a flow channel switching valve of this embodiment includes a cleaning liquid flow channel 26, a buffer flow channel 27, a waste liquid flow channel 21, a first mixing flow channel 24, a second mixing flow channel 25 and a flow channel switching valve 19; one end of the cleaning liquid flow channel 26, one end of the buffer flow channel 27, one end of the waste liquid flow channel 21, one end of the first mixing flow channel 24 and one end of the second mixing flow channel 25 are respectively connected to the flow channel switching valve 19, the other end of the cleaning liquid flow channel 26 is connected to the cleaning liquid injection device, the other end of the buffer flow channel 27 is connected to the buffer injection device, the other end of the waste liquid flow channel 21 is connected to the first waste liquid tank 22, and the other end of the first mixing flow channel 24 is connected to the sample hole, the immunomagnetic bead injection device, the gas injection device and the fluorescent antibody injection device. By connecting the first mixing flow channel 24 to the gas injection device and injecting gas into the first mixing flow channel 24, the liquid therein can flow into the valve chamber 3 under the action of air pressure. The second end of the second mixing channel 25 is connected to the inlet of the detection zone 29, and the outlet of the detection zone 29 is connected to the second waste liquid reservoir 23. The height of the detection zone 29 is less than the spacing between adjacent magnetic bead sample-antibody mixed microspheres. The channel switching valve 19 has a valve chamber 3 and has four operating states. In the first state, the cleaning liquid channel 26 is connected to the waste liquid channel 21 through the valve chamber 3. In the second state, the buffer channel 27 is connected to the second mixing channel 25 through the valve chamber 3. In the third state, the first mixing channel 24 is connected to the air vent connection tube 18 through the valve chamber 3. In the fourth state, no two channels are connected. The channel switching valve 19 is initially in the third operating state. To prevent the seal between the outer side of the valve chamber 3 and the channel from leaking liquid, a sealing strip 28 is provided on the upper layer of the channel switching valve 19 at the top edge of the valve chamber 3 to seal the valve body and the side, preventing liquid from leaking out of the microfluidic chip. The sealing strip 28 can be made of a soft, sealable material such as silicone or PDMS. The gas injection device, the cleaning liquid injection device, the buffer injection device, the immunomagnetic bead injection device and the fluorescent antibody injection device respectively use an empty vesicle 11, a cleaning liquid vesicle 8 filled with cleaning liquid, a buffer vesicle filled with buffer, an immunomagnetic bead vesicle 10 filled with immunomagnetic beads and a fluorescent antibody vesicle 12 filled with fluorescent antibodies, and a vesicle puncture needle 20 is provided at the bottom of each vesicle.

[0032] The microfluidic chip with a flow channel switching valve of the present invention is composed of a first layer of boards, a second layer of boards, a third layer of boards, and a fourth layer of boards stacked in sequence, namely layer a, layer b, layer c, and layer d, with adjacent boards sealed and fitted together. The upper half of the waste liquid flow channel 21 is provided on layer c, and the lower half is provided on layer d. The sac is punctured on layer c. The upper half of the second waste liquid bin 23 and the upper half of the first waste liquid bin 22 are provided on layer c, while the lower half of the first waste liquid bin and the lower half of the second waste liquid bin are provided on layer d. Five sac mounting holes 16, a sealing strip interface 15 for installing a sealing strip 28, a positioning hole 13, a sample hole 17, and two exhaust holes 14 are provided on layer a. The right side of layer a can press against the sac sealing edge to ensure that no liquid leaks when the sac is punctured and squeezed. The b-layer board is provided with a valve pit 30 for installing the flow channel switching valve, a positioning hole 13, and five liquid sac mounting holes 16. It is also provided with an air hole connecting tube 18. One end of the air hole connecting tube 18 is used to connect to the exhaust hole 14 of the a-layer, and the other end is slidingly and sealingly connected to the side wall of the flow channel switching valve. The c-layer board is provided with a positioning hole 13, a first mixing flow channel 24, a second mixing flow channel 25, a valve pit 30 for installing the flow channel switching valve, a cleaning liquid flow channel 26, a buffer flow channel 27, the upper half of the waste liquid flow channel, a detection area 29, the upper half of the first waste liquid tank 22, and the upper half of the second waste liquid tank 23. The d-layer board is provided with a positioning hole, the lower half of the waste liquid flow channel, the lower half of the first waste liquid tank, and the lower half of the second waste liquid tank.

[0033] The working process of the microfluidic chip with a flow channel switching valve of the present invention is as follows:

[0034] 1) Inject the sample into the first mixing channel 24 through the syringe and the sample hole, and squeeze the immunomagnetic bead vesicles 10 and the fluorescent antibody vesicles 12 at the same time so that the sample, immunomagnetic beads and fluorescent antibodies all enter the first mixing channel 24. After the sample is injected, the needle tip of the syringe does not move away.

[0035] The sample, immunomagnetic beads and fluorescent antibodies begin to mix in the first mixing channel 24 .

[0036] 2) After the sample, immune magnetic beads and fluorescent antibodies are mixed, the empty vesicle 11 is squeezed to allow the mixed solution to enter the valve chamber 3 and the flow channel switching valve is twisted to put the flow channel switching valve in the fourth working state.

[0037] After the mixed solution enters the valve chamber 3, it begins to incubate and generate magnetic bead sample antibody mixed microspheres.

[0038] 3) After the incubation is completed, the magnetic bead sample antibody mixed microspheres in the valve chamber 3 are fixed by a magnet, the flow channel switching valve is twisted to put the flow channel switching valve in the first working state, and the cleaning liquid vesicles 8 are squeezed to clean the mixed microspheres.

[0039] The washing can remove excess unbound secondary antibodies, antigen impurities, etc. The waste liquid generated by the washing will flow into the first waste liquid tank 22 through the waste liquid channel.

[0040] 4) After the washing is completed, the magnetic bead sample-antibody mixed microspheres are released, and the flow channel switching valve is twisted to put the flow channel switching valve into the second working state to squeeze the buffer vesicles.

[0041] As the buffer enters the second cleaning chamber 10, the resulting magnetic bead, sample, and antibody mixed microsphere solution flows through the second mixing channel 25 into the detection zone 29. Because the depth of the detection zone 29 is less than the spacing between adjacent magnetic bead, sample, and antibody mixed microspheres, once the magnetic bead, sample, and antibody mixed microspheres and the buffer fill the detection zone 29, the magnetic beads will be spread evenly in the detection zone 29. Excess liquid will flow into the second waste liquid chamber 23.

[0042] 5) After the detection area 29 is filled with the magnetic bead sample antibody mixed microsphere solution, the magnetic beads and microspheres in the detection area 29 are counted to obtain the concentration of the antigen in the sample.

[0043] The detection area 29 can be photographed by a camera and the magnetic beads and microspheres can be counted using image recognition technology.

[0044] Because the height of the detection area 29 is less than the spacing between adjacent magnetic bead sample antibody mixed microspheres, the magnetic beads can be automatically flattened in a focal plane, avoiding the problem of mixed microspheres overlapping up and down in the detection area 29 and affecting the counting. There is no need to set up multiple microwells in the chip and drop the mixed microspheres into them, and there is no need to use oil layers or other reagents to flush the mixed microspheres after entering the detection area 29. The flow channel switching valve has a valve cavity 3, which can serve as a double antibody sandwich incubation area and a position for washing excess microspheres. In the third state, the mixed microspheres in the first mixing channel 24 can be allowed to enter the valve cavity 3 for incubation. In the first state, the incubated mixed microspheres can be washed with a cleaning liquid, and the waste liquid can be flowed into the waste liquid tank through the waste liquid pipeline. After the cleaning is completed, the second state is switched to inject a buffer solution into the valve cavity 3 to flush the mixed microspheres into the detection area 29 through the second mixing channel 25 for counting. Using the microfluidic chip of the present invention for antigen concentration detection can make the operating steps of the entire process simpler, improve the efficiency of antigen concentration detection, and greatly save the production cost of the microfluidic chip.

[0045] Example 2 of a microfluidic chip with a flow channel switching valve:

[0046] like Figure 6 and Figure 7 As shown, the difference between the channel switching valve in this embodiment and the channel switching valve in the microfluidic chip embodiment 1 with a channel switching valve is that the first valve port 4 and the third valve port 6 are opened at the top of the valve body, and the second valve port 5 and the fourth valve port are opened at the bottom of the valve body.

[0047] like Figure 8 and Figure 9 As shown, the microfluidic chip with a flow channel switching valve in this embodiment differs from the microfluidic chip with a flow channel switching valve in Example 1 in that the valve pit 30 for mounting the flow channel switching valve body is located on layer c, the sac puncture needle 20 is located on layer b, and layer b also has a valve hole for mounting the flow channel switching valve column 2. The waste liquid channel 21 and the lower half of the first waste liquid reservoir are located on layer d and the upper half is located on layer c. The lower half of the second waste liquid reservoir 23 is located on layer d and the upper half is located on layer c. The cleaning liquid channel 26, the buffer channel 27, and the first mixing channel 24 are all located on the board on layer b. The second mixing channel 25 is located on layer c.

[0048] The working principle of the microfluidic chip with a flow channel switching valve in this embodiment is the same as the working principle of the microfluidic chip with a flow channel switching valve in Example 1 of the microfluidic chip with a flow channel switching valve, and will not be repeated here.

Claims

1. A microfluidic chip with a flow channel switching valve, characterized in that: The device comprises a cleaning liquid flow channel, a buffer flow channel, a waste liquid flow channel, a first mixing flow channel, a second mixing flow channel and a flow channel switching valve; one end of the cleaning liquid flow channel, the buffer flow channel, the waste liquid flow channel, the first mixing flow channel and the second mixing flow channel are respectively connected to the flow channel switching valve, the other end of the cleaning liquid flow channel is connected to the cleaning liquid injection device, the other end of the buffer flow channel is connected to the buffer injection device, the other end of the waste liquid flow channel is connected to the first waste liquid tank, the other end of the first mixing flow channel is connected to the gas injection device, the sample well, the immunomagnetic bead injection device and the fluorescent antibody injection device, the second end of the second mixing flow channel is connected to the inlet of the detection zone, and the outlet of the detection zone is connected to the second waste liquid tank; the height of the detection zone is less than the spacing between adjacent magnetic bead sample antibody mixed microspheres; The flow channel switching valve has a valve cavity and has the following four working states: the cleaning liquid flow channel is connected to the waste liquid flow channel through the valve cavity, the buffer flow channel is connected to the second mixing flow channel through the valve cavity, the first mixing flow channel is connected to the air hole connecting pipe through the valve cavity, and any two flow channels are not connected; The flow channel switching valve includes a cylindrical valve body, a torque valve groove fixedly connected to the valve body for driving the valve body to rotate, and a valve column fixedly connected to the top of the valve body. The valve cavity is located inside the valve body, and the outer surface of the valve body is slidingly and sealingly connected to the flow channel openings of the pore connecting pipe, the cleaning liquid flow channel, the buffer flow channel, the waste liquid flow channel, the first mixing flow channel and the second mixing flow channel respectively. The valve body is respectively provided with a first valve port for connecting the cleaning liquid flow channel and the valve cavity or connecting the buffer flow channel and the valve cavity, a second valve port for connecting the second mixing flow channel and the valve cavity or connecting the waste liquid flow channel and the valve cavity, a third valve port for connecting the first mixing flow channel and the valve cavity, and a fourth valve port for connecting the valve cavity and the pore connecting pipe; the positions of the four valve ports must ensure that when the first valve port is in a position connected to the cleaning liquid flow channel, the second valve port is in a position connected to the waste liquid flow channel; when the first valve port is in a position connected to the buffer flow channel, the second valve port is in a position connected to the second mixing flow channel; when the third valve port is in a position connected to the first mixing flow channel, the fourth valve port is in a position connected to the pore connecting pipe.

2. The microfluidic chip with a flow channel switching valve according to claim 1, wherein: The torque valve slot is arranged inside the valve column.

3. The microfluidic chip with a flow channel switching valve according to claim 1, wherein: The positions of the first valve port, the second valve port, the third valve port and the fourth valve port are such that all four are opened on the side of the valve body or the first valve port and the third valve port are opened on the top of the valve body, and the second valve port and the fourth valve port are opened on the bottom of the valve body.

4. The microfluidic chip with a flow channel switching valve according to claim 1, wherein: The gas injection device, the cleaning liquid injection device, the buffer solution injection device, the immunomagnetic bead injection device and the fluorescent antibody injection device all use vesicles, and a vesicle puncture needle is arranged at the bottom of the vesicles.

5. The microfluidic chip with a flow channel switching valve according to any one of claims 1 to 4, characterized in that: The microfluidic chip is formed by stacking at least two layers of plates, and adjacent plates are sealed and fitted together. The cleaning liquid flow channel, buffer flow channel, waste liquid flow channel, first mixing flow channel and second mixing flow channel are all opened on the plates.

6. The microfluidic chip with a flow channel switching valve according to claim 5, characterized in that: A sealing strip interface for installing a sealing strip is provided on the outermost plate. The sealing strip is used to prevent liquid on the contact surface between the valve body of the channel switching valve and the channel opening from leaking to the outside of the microfluidic chip.

7. The microfluidic chip with a flow channel switching valve according to claim 5, characterized in that: The microfluidic chip is composed of a first layer of boards, a second layer of boards, a third layer of boards and a fourth layer of boards stacked in sequence, wherein the first layer is provided with a positioning hole, an exhaust hole, a sealing strip interface, a sample hole and five liquid capsule mounting holes, the second layer is provided with a positioning hole, a gas connecting pipe, a valve pit for installing a flow channel switching valve and five liquid capsule mounting holes, the third layer is provided with a positioning hole, a first mixing flow channel, a second mixing flow channel, a valve pit for installing a flow channel switching valve, a cleaning liquid flow channel, a buffer flow channel, the upper half of the waste liquid flow channel, a detection area, the upper half of the first waste liquid bin and the upper half of the second waste liquid bin, the fourth layer is provided with a positioning hole, the lower half of the waste liquid flow channel, the lower half of the first waste liquid bin and the lower half of the second waste liquid bin.

8. The microfluidic chip with a flow channel switching valve according to claim 5, characterized in that: The microfluidic chip is composed of a first layer of boards, a second layer of boards, a third layer of boards and a fourth layer of boards stacked in sequence, wherein the first layer is provided with a positioning hole, an exhaust hole, a sample hole and five liquid capsule mounting holes, the second layer is provided with a positioning hole, a valve hole, a first mixing flow channel, a cleaning liquid flow channel, a buffer flow channel and five liquid capsule mounting holes, the third layer is provided with a valve pit, a positioning hole, the upper half of the waste liquid flow channel, the second mixing flow channel, the detection area, the upper half of the first waste liquid bin and the upper half of the second waste liquid bin, the fourth layer is provided with a positioning hole, the lower half of the waste liquid flow channel, the lower half of the first waste liquid bin and the lower half of the second waste liquid bin.

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