A magnetic-acoustic combined cell separation microfluidic chip and method thereof

Abstract

The invention relates to the technical field of cell screening, and discloses a magnetic-acoustic combined cell separation microfluidic chip and a method thereof, comprising a chip bottom plate, a cell cache box, a first sorting channel, a second sorting channel, a semicircular channel, a switch mechanism, an output mechanism, a main channel, a first transducer, a second transducer and a magnet, wherein a first liquid inlet is connected with a first liquid outlet through a semicircular channel, a second liquid inlet is arranged on the cell cache box, one end of the cell cache box is connected with the semicircular channel, the semicircular channel is connected with the first liquid inlet, the other end of the cell cache box is connected with the switch mechanism, the switch mechanism is connected with the output mechanism through the main channel, the main channel is connected with the second liquid outlet and the third liquid outlet through the output mechanism, a magnet is located between the output mechanism and the chip bottom plate, the first and second transducers generate body sound waves, the operating frequency is low, high temperature is not easily generated, and cells will not be damaged, and a combination of acoustic field and magnetic field is adopted to improve separation purity and efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of cell screening, and in particular to a magnetic-acoustic combined cell separation microfluidic chip and a method thereof. Background Art

[0002] There are many kinds of cells in the body, such as blood cells, lymphocytes, germ cells, etc. The rapidly developing field of cell medicine also requires efficient and simple cell separation technology. For example, the use of pure red blood cells, platelets and plasma transfusions for blood component therapy has more advantages than the use of whole blood; pure white blood cells are also often used for transplantation, so the rapid separation of red blood cells, white blood cells and platelets from whole blood solutions is crucial for accurate and rapid medical diagnosis. At present, there are two commonly used cell separation methods: contact and non-contact. Among them, non-contact methods can avoid contamination, maintain cell activity and operate continuously. Non-contact separation technologies mainly include dielectric force, optical gradient force, magnetic force and acoustic radiation force. Ultrasonic separation methods mainly use the difference in cell size, density or compressibility, and the different acoustic flow and acoustic radiation force they are subjected to to separate cells. However, some existing cell separation methods are time-consuming and costly, and it is easy to activate platelets. Existing separation methods based on cell size differences are also difficult to separate red blood cells and white blood cells. Therefore, it is of great significance to find a cost-effective method with high purity and high yield that meets quality requirements. Microfluidic chips used for particle separation usually design a tip structure in the microchannel and use the acoustic flow phenomenon generated at the tip to capture microparticles, which makes the microchannel processing difficult. Traditional microfluidic ultrasonic separation chips usually distinguish the particles based on their different acoustic contrast coefficients to achieve separation, but the acoustic contrast coefficients of red blood cells and white blood cells are both positive, so this principle cannot be used to achieve separation. Traditional cell separation methods such as wall adhesion and cold focusing are limited to separation using a single method, and the separation efficiency and purity need to be improved.

[0003] The prior art discloses a microfluidic whole blood cell multi-stage sorting chip and method based on surface acoustic wave. The chip includes a piezoelectric substrate, on which two groups of interdigital transducers are sputtered, and a PDMS microfluidic system is bonded on the piezoelectric substrate and on one side of the two groups of interdigital transducers. The method utilizes two groups of interdigital transducers, combined with two-stage sorting microfluidics, to achieve sequential sorting of white blood cells, red blood cells and platelets by applying different frequencies and voltages. This technology uses a blood cell sorting method based on surface acoustic wave. When the transducer is working, the output frequency is too high, which can easily lead to high temperature and damage cells. Summary of the invention

[0004] The purpose of the present invention is to provide a magnetic-acoustic combined cell separation microfluidic chip and a method thereof. The present invention has a low operating frequency, is not easy to generate high temperature, and will not damage cells. In addition, the present invention adopts a separation method that combines acoustic field and magnetic field to improve the purity and efficiency of cell separation.

[0005] In order to achieve the above-mentioned objectives, the present invention provides a magnetic-acoustic combined cell separation microfluidic chip, comprising a chip base plate, a cell cache box, a first sorting channel, a second sorting channel, a semicircular channel, a switch mechanism, an output mechanism, a main channel, a first transducer, a second transducer and a magnet, wherein the cell cache box, the first sorting channel, the second sorting channel, the semicircular channel, the switch mechanism, the output mechanism, the main channel and the magnet are all located on the chip base plate, a transducer bonding area is provided on the chip base plate, the first transducer is connected to the transducer bonding area, the chip base plate is also provided with a liquid outlet and a first liquid inlet, the liquid outlet comprises a first liquid outlet, a second liquid inlet and a second liquid inlet. two liquid outlets and a third liquid outlet, one end of the semicircular channel is connected to the first liquid inlet, the other end of the semicircular channel is connected to the first liquid outlet, the second liquid inlet is provided on the cell cache box, one end of the cell cache box is connected to the semicircular channel through the first sorting channel and the second sorting channel, the other end of the cell cache box is connected to the switch mechanism, one end of the main channel is connected to the output end of the switch mechanism, the other end of the main channel is connected to the second liquid outlet and the third liquid outlet through the output mechanism, the magnet is installed on the side of the output mechanism located at the third liquid outlet, and the second transducer is installed on the outside of the main channel.

[0006] Preferably, the number of the third liquid outlets is two, and the two third liquid outlets are respectively located on both sides of the second liquid outlet.

[0007] Preferably, the chip base plate is also provided with an air inlet, and the air inlet is connected to the cell cache box.

[0008] Preferably, it also includes an input channel, and the air inlet is connected to the cell cache box through the input channel.

[0009] Preferably, the cross section of the input channel is rectangular, and the cross section of the main channel is rectangular.

[0010] Preferably, the output mechanism includes an intermediate channel, a side channel and a star-shaped structure, the number of the side channels is two, one end of the intermediate channel is connected to the second liquid outlet, the other end of the intermediate channel is connected to the main channel through the star-shaped structure, one end of the two side channels are respectively connected to the two third liquid outlets, and the other end of the two side channels are respectively connected to the main channel through the star-shaped structure.

[0011] Preferably, a leukocyte adsorption chamber is provided between the star-shaped structure and the two side channels respectively, the liquid inlet of the leukocyte adsorption chamber is connected to the star-shaped structure, the liquid outlet of the leukocyte adsorption chamber is connected to the side channel, and the magnet is located outside the leukocyte adsorption chamber.

[0012] Preferably, the switching mechanism includes a sealing valve and a storage box, one end of the sealing valve is connected to the cell cache box, and the other end of the sealing valve is connected to the main channel, the sealing valve is used to open and close the cell cache box, and the storage box is used to store sealed materials.

[0013] Preferably, the sealing valve is a wax valve, the storage box is a wax storage box, and the first transducer and the second transducer are piezoelectric ceramic transducers.

[0014] A magnetic-acoustic combined cell separation method comprises the following steps:

[0015] S1. First, inject the whole blood solution sample from the first liquid inlet, adjust the frequency of the first transducer, generate an acoustic field effect, and when the whole blood solution sample passes through the semicircular channel, the red and white blood cells flow out of the semicircular channel from the first sorting channel and the second sorting channel and flow into the cell buffer box, and the platelets finally flow out of the chip through the first liquid outlet;

[0016] S2. Inject the medium density solution from the second liquid inlet, shake it by hand to fully mix it with the red blood cells and white blood cells in the cell buffer box, open the sealing valve, pump air at the air inlet with an air pump to push the liquid to flow, so that the mixed solution flows out of the main channel, adjust the frequency of the second transducer to generate an acoustic field effect on the mixed solution, and the red blood cells with higher density are focused in the middle of the channel, while the white blood cells with lower density are focused on both sides of the channel;

[0017] S3. When cells flow into the star-shaped channel, the white blood cells previously labeled with immunomagnetic beads are acted upon by the magnet and adsorbed into the white blood cell adsorption chamber, while the red blood cells pass through the middle channel and flow out of the chip from the second outlet. Finally, after the magnet is removed, the white blood cells pass through the side channel and flow out of the chip from the third outlet.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The whole blood solution sample is injected from the first liquid inlet, and the frequency of the first transducer is adjusted to generate an acoustic field effect. The whole blood solution sample is affected by the acoustic field in the semicircular channel. The red and white blood cells are focused and arranged at the sound pressure node under the effect of the acoustic radiation force in the acoustic field. Due to the use of a semicircular channel, they settle to the bottom after a period of time, and finally the red and white blood cells flow out from the first sorting channel and the second sorting channel and flow into the cell cache box. The platelets are less affected by the acoustic radiation force and flow out of the chip through the first liquid outlet. The intermediate density solution is injected from the second liquid inlet. After being fully mixed with the red blood cells and white blood cells in the cell cache box, the switch mechanism is turned on. The mixed solution flows out from the cell buffer box, and the frequency of the second transducer is adjusted to generate an acoustic field effect. The red blood cells with higher density are focused in the middle of the main channel, while the white blood cells with lower density are focused on both sides of the main channel. The white blood cells previously labeled with immunomagnetic beads are adsorbed in the output mechanism by the action of the magnet, while the red blood cells flow out of the chip from the second liquid outlet. After the magnet is removed, the white blood cells flow out of the chip from the third liquid outlet. Since the first transducer and the second transducer generate body sound waves with lower operating frequencies, high temperatures are not easily generated, and cells will not be damaged. In addition, a separation method combining acoustic and magnetic fields is adopted to improve separation purity and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the internal structure of a cell separation microfluidic chip according to an embodiment of the present invention;

[0021] Figure 2 is a side view of a cell separation microfluidic chip according to an embodiment of the present invention;

[0022] Figure 3 Schematic diagram of the external structure of the cell separation microfluidic chip according to an embodiment of the present invention.

[0023] In the figure, 1. chip base plate; 2. cell cache box; 3. transducer bonding area; 4. first liquid inlet; 5. first liquid outlet; 6. second liquid outlet; 7. third liquid outlet; 8. second liquid inlet; 9. first sorting channel; 10. second sorting channel; 11. semicircular channel; 12. air inlet; 13. input channel; 14. main channel; 15. side channel; 16. middle channel; 17. leukocyte adsorption chamber; 18. sealing valve; 19. storage box; 20. first transducer; 21. magnet; 22. star structure; 23. second transducer. DETAILED DESCRIPTION

[0024] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0025] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0028] Embodiment 1

[0029] like Figure 1-3As shown, a magnetic-acoustic combined cell separation microfluidic chip according to a preferred embodiment of the present invention comprises a chip base plate 1, a cell buffer box 2, a first sorting channel 9, a second sorting channel 10, a semicircular channel 11, a switch mechanism, an output mechanism, a main channel 14, a first transducer 20, a second transducer 23 and a magnet 21. The cell buffer box 2, the first sorting channel 9, the second sorting channel 10, the semicircular channel 11, the switch mechanism, the output mechanism, the main channel 14 and the magnet 21 are all located on the chip base plate 1. A transducer bonding area 3 is provided on the chip base plate 1. The first transducer 20 is connected to the transducer bonding area 3 so that the first transducer 20 is bonded to the chip base plate 1. The plate 1 is fixed and the first transducer 20 can be accurately located in the working area. The chip bottom plate 1 is also provided with a liquid outlet and a first liquid inlet 4. The liquid outlet includes a first liquid outlet 5, a second liquid outlet 6 and a third liquid outlet 7. One end of the semicircular channel 11 is connected to the first liquid inlet 4, and the other end of the semicircular channel 11 is connected to the first liquid outlet 5. The cell buffer box 2 is provided with a second liquid inlet 8 to facilitate the injection of an intermediate density solution to fully mix with red and white blood cells. One end of the cell buffer box 2 is connected to the semicircular channel 11 through a first sorting channel 9 and a second sorting channel 10, so that white blood cells and red blood cells can enter the cell buffer through the first sorting channel 9 and the second sorting channel 10. The cell buffer box 2 is connected to the switch mechanism at the other end, so that the cell buffer box 2 can be opened or closed by the switch mechanism. One end of the main channel 14 is connected to the output end of the switch mechanism, and the other end of the main channel 14 is connected to the second liquid outlet 6 and the third liquid outlet 7 through the output mechanism. The magnet 21 is installed on the side of the output mechanism located at the third liquid outlet 7. The second transducer 23 is installed on the outside of the main channel 14. The whole blood solution sample is injected from the first liquid inlet 4, and the frequency of the first transducer 20 is adjusted to generate an acoustic field effect. The whole blood solution sample is affected by the acoustic field in the semicircular channel 11, and the red and white blood cells are focused by the acoustic radiation force in the acoustic field. They are arranged at the sound pressure node. Due to the use of a semicircular channel 11, they settle to the bottom after a period of time. Finally, white blood cells and red blood cells flow out from the first sorting channel 9 and the second sorting channel 10 and flow into the cell buffer box 2. Platelets are less affected by the acoustic radiation force and flow out of the chip through the first liquid outlet 5. The intermediate density solution is injected from the second liquid inlet 8. After being fully mixed with the red blood cells and white blood cells in the cell buffer box 2, the switch mechanism is turned on to make the mixed solution flow out from the main channel 14. The frequency of the second transducer 23 is adjusted to generate an acoustic field effect. The red blood cells with a larger density are focused in the middle of the main channel, and the white blood cells with a smaller density are focused on both sides of the main channel.The white blood cells marked with immunomagnetic beads in advance are adsorbed in the output mechanism by the magnet 21, while the red blood cells flow out of the chip from the second liquid outlet 6. After the magnet 21 is removed, the white blood cells flow out of the chip from the third liquid outlet 7. Since the first transducer and the second transducer generate body sound waves, the operating frequency is low, it is not easy to generate high temperature, and the cells will not be damaged. In addition, the separation method combining the acoustic field and the magnetic field is adopted to improve the separation purity and efficiency. ;

[0030] Specifically, there are two third liquid outlets 7 , and the third liquid outlets 7 are symmetrical about the second liquid outlet 6 . Due to the effect of the magnetic field, the white blood cells previously labeled with immune magnetic beads are distributed on both sides and discharged from the third liquid outlets 7 on both sides.

[0031] Embodiment 2

[0032] The difference between this embodiment and the first embodiment is that the chip base plate 1 is further provided with an air inlet 12, which is connected to the cell buffer box 2, so that the liquid in the cell buffer box 2 can be pushed into the main channel 14 and pushed to the output mechanism by an air pump.

[0033] It also includes an input channel 13 , through which the gas inlet 12 is connected to the cell cache box 2 , so as to facilitate the injection of gas into the cell cache box 2 .

[0034] The cross section of the input channel 13 is rectangular, and the cross section of the main channel 14 is rectangular.

[0035] The other structures of this embodiment are the same as those of the first embodiment and will not be described again here.

[0036] Embodiment 3

[0037] The difference between this embodiment and the second embodiment is that the output mechanism includes an intermediate channel 16, a side channel 15 and a star-shaped structure 22. There are two side channels 15, and the side channels 15 are symmetrically arranged about the intermediate channel 16. One end of the intermediate channel 16 is connected to the second liquid outlet 6, and the other end of the intermediate channel 16 is connected to the main channel 14 through the star-shaped structure 22. One end of the two side channels 15 is respectively connected to the two third liquid outlets 7, and the other end of the two side channels 15 is respectively connected to the main channel 14 through the star-shaped structure 22, so that red and white blood cells can flow out from different channels and liquid outlets.

[0038] A leukocyte adsorption chamber 17 is provided between the star-shaped structure 22 and the two side channels 15 , respectively. The liquid inlet of the leukocyte adsorption chamber 17 is connected to the star-shaped structure 22 , the liquid outlet of the leukocyte adsorption chamber 17 is connected to the side channel 15 , and the magnet 21 is located outside the leukocyte adsorption chamber 17 .

[0039] The switching mechanism includes a sealing valve 18 and a storage box 19. One end of the sealing valve 18 is connected to the cell cache box 2, and the other end of the sealing valve 18 is connected to the main channel 14. The sealing valve 18 is used to open and close the cell cache box 2, and the storage box 19 is used to store sealed objects.

[0040] The sealing valve 18 is a wax valve, and the storage box 19 is a wax storage box, so as to seal the cell cache box 2 with wax. The cell cache box 2 can be opened after the wax is melted using a heating plate.

[0041] The first transducer 20 and the second transducer 23 are piezoelectric ceramic transducers.

[0042] The other structures of this embodiment are the same as those of the second embodiment and will not be described again here.

[0043] A magnetic-acoustic combined cell separation method comprises the following steps:

[0044] S1. First, inject the whole blood solution sample from the first liquid inlet 4, adjust the frequency of the first transducer 20 to generate an acoustic field effect, and when the whole blood solution sample passes through the semicircular channel 11, the red and white blood cells flow out of the semicircular channel 11 from the first sorting channel 9 and the second sorting channel 10, and flow into the cell buffer box 2, and the platelets finally flow out of the chip through the first liquid outlet 5;

[0045] S2. Inject the medium density solution from the second liquid inlet, and after fully mixing it with the red blood cells and white blood cells in the cell buffer box 2 by shaking it by hand, open the sealing valve 18, pump air at the air inlet 12 with an air pump to push the liquid to flow, so that the mixed solution flows through the main channel 14, and adjust the frequency of the second transducer 23 to generate an acoustic field effect on the mixed solution, so that the red blood cells with larger density are focused in the middle of the channel, and the white blood cells with smaller density are focused on both sides of the channel;

[0046] S3. When the cells flow into the star-shaped channel, the white blood cells previously labeled with the immunomagnetic beads are acted upon by the magnet 21 and adsorbed to the white blood cell adsorption chamber 17, while the red blood cells pass through the middle channel 16 and flow out of the chip from the second liquid outlet 6. Finally, after the magnet 21 is removed, the white blood cells pass through the side channel 15 and flow out of the chip from the third liquid outlet 7.

[0047] In summary, the embodiment of the present invention provides a magnetic-acoustic combined cell separation microfluidic chip, including a chip base plate 1, a cell cache box 2, a first sorting channel 9, a second sorting channel 10, a semicircular channel 11, a switch mechanism, an output mechanism, a main channel 14, a first transducer 20, a second transducer 23 and a magnet 21, the cell cache box 2, the first sorting channel 9, the second sorting channel 10, the semicircular channel 11, the switch mechanism, the output mechanism, the main channel 14 and the magnet 21 are all located on the chip base plate 1, and the chip The base plate 1 is provided with a transducer bonding area 3, and the first transducer 20 is connected to the transducer bonding area 3, so that the first transducer 20 is fixed to the chip base plate 1 and the first transducer 20 can be accurately located in the working area. The chip base plate 1 is also provided with a liquid outlet and a first liquid inlet 4, and the liquid outlet includes a first liquid outlet 5, a second liquid outlet 6 and a third liquid outlet 7. One end of the semicircular channel 11 is connected to the first liquid inlet 4, and the other end of the semicircular channel 11 is connected to the first liquid outlet 5. The cell cache box 2 is provided with a second liquid inlet 8, so that the intermediate density solution can be injected to fully mix with the red and white blood cells. One end of the cell cache box 2 is connected to the semicircular channel 11 through the first sorting channel 9 and the second sorting channel 10, so that the white blood cells and red blood cells can enter the cell cache box 2 through the first sorting channel 9 and the second sorting channel 10. The other end of the cell cache box 2 is connected to the switch mechanism, so that the cell cache box 2 can be opened or closed by the switch mechanism. One end of the main channel 14 is connected to the output end of the switch mechanism, and the other end of the main channel 14 is connected to the second liquid outlet 6 and the third liquid outlet 7 through the output mechanism. The magnet 21 is installed on the side of the output mechanism located at the third liquid outlet 7. The second transducer 23 is installed on the outside of the main channel 14. The whole blood solution sample is injected from the first liquid inlet 4, and the frequency of the first transducer 20 is adjusted to generate an acoustic field effect. Since the first transducer and the second transducer generate body acoustic waves, the operating frequency is low, it is not easy to generate high temperature, and it will not damage the cells. In addition, a separation method combining acoustic field and magnetic field is adopted to improve the separation purity and efficiency.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A magnetic-acoustic combined cell separation microfluidic chip, characterized in that: The invention comprises a chip base plate (1), a cell cache box (2), a first sorting channel (9), a second sorting channel (10), a semicircular channel (11), a switch mechanism, an output mechanism, a main channel (14), a first transducer (20), a second transducer (23) and a magnet (21), wherein the cell cache box (2), the first sorting channel (9), the second sorting channel (10), the semicircular channel (11), the switch mechanism, the output mechanism, the main channel (14) and the magnet (21) are all located on the chip base plate (1), a transducer bonding area (3) is provided on the chip base plate (1), the first transducer (20) is connected to the transducer bonding area (3), the chip base plate (1) is also provided with a liquid outlet and a first liquid inlet (4), the liquid outlet comprises a first liquid outlet (5), a second liquid outlet (6) and a third liquid outlet (7). A liquid port (7), one end of the semicircular channel (11) is connected to the first liquid inlet (4), the other end of the semicircular channel (11) is connected to the first liquid outlet (5), a second liquid inlet (8) is provided on the cell cache box (2), one end of the cell cache box (2) is connected to the semicircular channel (11) through the first sorting channel (9) and the second sorting channel (10), the other end of the cell cache box (2) is connected to the switch mechanism, one end of the main channel (14) is connected to the output end of the switch mechanism, the other end of the main channel (14) is connected to the second liquid outlet (6) and the third liquid outlet (7) through the output mechanism, the magnet (21) is installed on the side of the output mechanism located at the third liquid outlet (7), and the second transducer (23) is installed on the outside of the main channel (14).

2. The magnetic-acoustic combined cell separation microfluidic chip according to claim 1, characterized in that: The number of the third liquid outlets (7) is two, and the two third liquid outlets (7) are respectively located on both sides of the second liquid outlet (6).

3. The magnetic-acoustic combined cell separation microfluidic chip according to claim 2, characterized in that: The chip base plate (1) is also provided with an air inlet (12), and the air inlet (12) is connected to the cell cache box (2).

4. The magnetic-acoustic combined cell separation microfluidic chip according to claim 3, characterized in that: It also includes an input channel (13), and the air inlet (12) is connected to the cell cache box (2) through the input channel (13).

5. The magnetic-acoustic combined cell separation microfluidic chip according to claim 4, characterized in that: The cross section of the input channel (13) is rectangular, and the cross section of the main channel (14) is rectangular.

6. The magnetic-acoustic combined cell separation microfluidic chip according to claim 2, characterized in that: The output mechanism comprises an intermediate channel (16), a side channel (15) and a star-shaped structure (22); the number of the side channels (15) is two; one end of the intermediate channel (16) is connected to the second liquid outlet (6); the other end of the intermediate channel (16) is connected to the main channel (14) through the star-shaped structure (22); one end of the two side channels (15) is respectively connected to the two third liquid outlets (7); the other end of the two side channels (15) is respectively connected to the main channel (14) through the star-shaped structure (22).

7. The microfluidic chip for separating cells by combining magnetic and acoustic combination according to claim 6, characterized in that: A leukocyte adsorption chamber (17) is provided between the star-shaped structure (22) and the two side channels (15), respectively; a liquid inlet of the leukocyte adsorption chamber (17) is connected to the star-shaped structure (22); a liquid outlet of the leukocyte adsorption chamber (17) is connected to the side channel (15); and the magnet (21) is located outside the leukocyte adsorption chamber (17).

8. The magnetic-acoustic combined cell separation microfluidic chip according to claim 7, characterized in that: The switch mechanism includes a sealing valve (18) and a storage box (19), one end of the sealing valve (18) is connected to the cell cache box (2), and the other end of the sealing valve (18) is connected to the main channel (14), the sealing valve (18) is used to open and close the cell cache box (2), and the storage box (19) is used to store sealed materials.

9. The magnetic-acoustic combined cell separation microfluidic chip according to claim 8, characterized in that: The sealing valve (18) is a wax valve, the storage box (19) is a wax storage box, and the first transducer (20) and the second transducer (23) are piezoelectric ceramic transducers.

10. A method for separating cells by combining magnetic and acoustic methods, applied to the microfluidic chip for separating cells by combining magnetic and acoustic methods as claimed in claim 8, comprising the following steps: S1. First, a whole blood solution sample is injected from the first liquid inlet (4), and the frequency of the first transducer (20) is adjusted to generate an acoustic field effect. When the whole blood solution sample passes through the semicircular channel (11), red blood cells and white blood cells flow out of the semicircular channel (11) from the first sorting channel (9) and the second sorting channel (10), and flow into the cell buffer box (2), and platelets finally flow out of the chip through the first liquid outlet (5); S2. Inject the intermediate density solution from the second liquid inlet, and after fully mixing it with the red blood cells and white blood cells in the cell buffer box (2) by shaking it manually, open the sealing valve (18), pump air at the air inlet (12) with an air pump to push the liquid to flow, so that the mixed solution flows out from the main channel (14), and adjust the frequency of the second transducer (23) to generate an acoustic field effect on the mixed solution, so that the red blood cells with higher density are focused in the middle of the channel, and the white blood cells with lower density are focused on both sides of the channel; S3. When the cells flow into the star-shaped channel, the white blood cells previously labeled with immunomagnetic beads are acted upon by the magnet (21) and adsorbed to the white blood cell adsorption chamber (17), while the red blood cells pass through the middle channel (16) and flow out of the chip from the second liquid outlet (6). Finally, after the magnet (21) is removed, the white blood cells pass through the side channel (15) and flow out of the chip from the third liquid outlet (7).

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