A microfluidic chip

Abstract

The present invention provides a microfluidic chip, which includes, from top to bottom, a top cover plate, an upper flow channel structure layer, a lower flow channel structure layer, and a bottom cover plate, wherein the upper surface of the upper flow channel structure layer is provided with a liquid reservoir, a liquid input flow channel, a detection chamber, and a waste liquid discharge flow channel, and the two ends of the detection chamber are respectively connected to the liquid input flow channel and the waste liquid discharge flow channel; the top cover plate is provided with a sample addition hole connected to the liquid reservoir and a waste liquid hole connected to the waste liquid discharge flow channel; wherein the microfluidic chip also includes a piezoelectric micropump for unidirectionally transmitting liquid from the liquid reservoir to the liquid input flow channel, the piezoelectric micropump includes piezoelectric micropump flow channels located in the upper and lower flow channel structure layers and respectively connected to the liquid reservoir and the liquid input flow channel, and a piezoelectric film located on the lower surface of the bottom cover plate and aligned with the piezoelectric micropump flow channels. The microfluidic chip of the present invention integrates a piezoelectric micropump, can realize active fluid control from the liquid reservoir to the detection chamber, and can realize multi-liquid path switching.

Description

Technical Field

[0001] The invention belongs to the fields of microfluidics and medical diagnosis, and relates to a microfluidics chip. Background Art

[0002] The immunosorbent assay (ELISA) based on antigen-antibody reaction is widely used in medical diagnosis and biological research in colleges and universities. Current immunosorbent reaction consumables include ELISA plates, paper chromatography and passive laminar flow. These methods have room for improvement in terms of large reagent usage or uncontrollable reagent loading. Active liquid delivery using a microfluidic integrated flow pump is one of the solutions to reduce reagent usage and control reagent loading. However, most of the flow pumps used in microfluidics are large in size, such as syringe pumps and compressed air pumps. Although there are many micropump solutions on the market, especially micropumps based on thermal bubble and piezoelectric principles, the structural integration solution of microfluidic chips cannot well integrate the two. Summary of the Invention

[0003] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a microfluidic chip for solving the problem of large flow pump volume in active liquid transportation of microfluidic chips in the prior art.

[0004] To achieve the above-mentioned and other related purposes, the present invention provides a microfluidic chip, comprising:

[0005] An upper flow channel structure layer, wherein the upper surface of the upper flow channel structure layer is provided with a liquid storage tank, a liquid input flow channel, a detection chamber and a waste liquid discharge flow channel, and the two ends of the detection chamber are respectively connected to the liquid input flow channel and the waste liquid discharge flow channel;

[0006] A top cover plate is located above the upper flow channel structure layer, and is provided with a sample addition hole and a waste liquid hole in the top cover plate, wherein the sample addition hole is connected to the liquid reservoir, and the waste liquid hole is connected to the waste liquid discharge flow channel;

[0007] A lower flow channel structure layer, located below the upper flow channel structure layer;

[0008] A bottom cover plate, located below the lower flow channel structure layer;

[0009] A piezoelectric micropump includes a piezoelectric micropump channel and a piezoelectric film. The piezoelectric micropump channel is located in the upper channel structure layer and the lower channel structure layer, and is connected to the liquid reservoir and the liquid input channel respectively. The piezoelectric film is located on the lower surface of the bottom cover plate and is aligned with the piezoelectric micropump channel. The piezoelectric micropump is used to unidirectionally transmit liquid from the liquid reservoir to the liquid input channel.

[0010] Optionally, a first concave cavity and a second concave cavity are provided on the lower surface of the upper flow channel structure layer, the liquid reservoir is connected to the first concave cavity via a first through hole penetrating the upper flow channel structure layer, the second concave cavity is connected to the liquid input flow channel via a second through hole penetrating the upper flow channel structure layer, and a first diaphragm is placed in the first concave cavity;

[0011] A third concave cavity aligned with the first concave cavity and a fourth concave cavity aligned with the second concave cavity are provided on the upper surface of the lower flow channel structure layer, a second diaphragm is placed in the fourth concave cavity, a fifth concave cavity is provided on the lower surface of the lower flow channel structure layer, a piezoelectric film is placed in the fifth concave cavity, and a lower transmission flow channel, a sixth concave cavity aligned with the third concave cavity and a seventh concave cavity aligned with the fourth concave cavity are provided at the bottom of the fifth concave cavity, both ends of the lower transmission flow channel are communicated with the sixth concave cavity and the seventh concave cavity respectively, the third concave cavity is communicated with the sixth concave cavity via a third through hole penetrating the lower flow channel structure layer, and the fourth concave cavity is communicated with the seventh concave cavity via a fourth through hole penetrating the lower flow channel structure layer;

[0012] Among them, the first through hole, the first concave cavity, the first diaphragm, the third concave cavity, the third through hole and the sixth concave cavity together constitute a first piezoelectric micropump one-way valve, the second through hole, the second concave cavity, the second diaphragm, the fourth concave cavity, the fourth through hole and the seventh concave cavity together constitute a second piezoelectric micropump one-way valve, and the first piezoelectric micropump one-way valve, the lower transmission channel, the fifth concave cavity, the second piezoelectric micropump one-way valve and the piezoelectric film together constitute the piezoelectric micropump.

[0013] Optionally, the opening area of ​​the first cavity is larger than the opening area of ​​the third cavity, the first diaphragm includes a suspension portion, the suspension portion is suspended above the third cavity and covers the bottom of the first through hole, and the opening area of ​​the third cavity is larger than the area of ​​the portion of the suspension portion suspended above the third cavity.

[0014] Optionally, a groove surrounding or partially surrounding the first through hole is provided at the bottom of the first cavity.

[0015] Optionally, at least one boss is provided at the bottom of the third cavity, the surface of the boss is lower than the top surface of the lower flow channel structure layer, and the boss is close to one end where the suspension portion is anchored.

[0016] Optionally, the first diaphragm and the second diaphragm are made of flexible material.

[0017] Optionally, the top cover plate, the upper flow channel structure layer and the lower flow channel structure layer are made of any one of glass, silicon and plastic, and the bottom cover plate is made of a flexible material, or the bottom cover plate is made of hard plastic with a thickness of less than 2 mm.

[0018] Optionally, the top cover plate, the upper flow channel structure layer, the lower flow channel structure layer and the bottom cover plate are connected by any one of gluing, chemical bonding and hot pressing bonding.

[0019] Optionally, the microfluidic chip comprises at least two sample addition holes, at least two liquid reservoirs and at least two piezoelectric micropumps, and each liquid reservoir transmits liquid to the detection chamber in a unidirectional manner through a different piezoelectric micropump.

[0020] Optionally, the microfluidic chip includes at least two reaction chambers.

[0021] Optionally, the microfluidic chip is used for immunoadsorption reaction or gene probe reaction.

[0022] As described above, the microfluidic chip of the present invention integrates a piezoelectric micropump, enabling active fluid control from the liquid reservoir to the detection chamber and preventing backflow. When the microfluidic chip includes multiple liquid reservoirs and multiple piezoelectric micropumps, multiple fluid path switching can also be achieved. The microfluidic chip of the present invention can be applied to a variety of reactions, including but not limited to immunosorbent reactions and gene probe reactions, by simply adding the desired samples and reagents to the liquid reservoir based on the desired reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is a schematic structural diagram of the microfluidic chip of the present invention.

[0024] Figure 2 Shown is a schematic diagram of the three-dimensional structure of the upper flow channel structure layer.

[0025] Figure 3 Shown is a top view of the upper flow channel structure layer.

[0026] Figure 4 Shown is a bottom view of the upper flow channel structure layer.

[0027] Figure 5 Shown is a three-dimensional structural diagram of the top cover plate.

[0028] Figure 6 Shown is a top view of the top cover plate.

[0029] Figure 7 Shown is a schematic diagram of the three-dimensional structure of the lower flow channel structure layer.

[0030] Figure 8 Shown is a top view of the lower flow channel structure layer.

[0031] Figure 9 Shown is a bottom view of the lower runner structure layer.

[0032] Figure 10 Shown is a three-dimensional diagram of the cross-sectional structure of the first piezoelectric micropump one-way valve (including the invisible part).

[0033] Figure 11 Shown is a three-dimensional diagram of the cross-sectional structure of the first piezoelectric micropump one-way valve (visible part).

[0034] Figure 12 Shown is a schematic diagram of the exploded structure of the cross-sectional structure of the first piezoelectric micropump one-way valve.

[0035] Figure 13 Shown is a schematic diagram of the exploded structure of the cross-sectional structure of the first piezoelectric micropump one-way valve at another angle.

[0036] Component number description

[0037] 100 top cover

[0038] 101 sample wells

[0039] 102 waste liquid hole

[0040] 200 Upper flow channel structure layer

[0041] 201 Reservoir

[0042] 202 liquid input channel

[0043] 203 Detection Chamber

[0044] 204 Waste liquid discharge channel

[0045] 205 First cavity

[0046] 206 Second cavity

[0047] 207 First through hole

[0048] 208 Second through hole

[0049] 209 First diaphragm

[0050] 209a Suspension

[0051] 210 grooves

[0052] 300 Lower flow channel structure layer

[0053] 301 lower transmission channel

[0054] 302 third cavity

[0055] 303 Fourth cavity

[0056] 304 Fifth Cavity

[0057] 305 Sixth Cavity

[0058] 306 Seventh Concave

[0059] 307 third through hole

[0060] 308 fourth through hole

[0061] 309 boss

[0062] 400 bottom cover DETAILED DESCRIPTION

[0063] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0064] See also Figures 1 to 13 It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0065] Example 1

[0066] The present invention provides a microfluidic chip, please refer to Figure 1 , which is a schematic structural diagram of the microfluidic chip, includes a top cover plate 100, an upper flow channel structure layer 200, a lower flow channel structure layer 300 and a bottom cover plate 400 arranged in sequence from top to bottom, and the microfluidic chip also includes a piezoelectric micropump.

[0067] For details, please refer to Figures 2 to 4 ,in, Figure 2 It is a schematic diagram of the three-dimensional structure of the upper flow channel structure layer 200. Figure 3 Shown is a top view of the upper flow channel structure layer, Figure 4It shows an overhead view of the upper flow channel structure layer. It can be seen that the upper surface of the upper flow channel structure layer 200 is provided with a liquid storage tank 201, a liquid input flow channel 202, a detection chamber 203 and a waste liquid discharge flow channel 204, and the two ends of the detection chamber 203 are respectively connected to the liquid input flow channel 202 and the waste liquid discharge flow channel 204.

[0068] As an example, the opening area of ​​one end of the detection chamber 203 connected to the liquid input channel 202 gradually expands from the liquid input channel 202 to the detection chamber 203, and the opening area of ​​one end of the detection chamber 204 connected to the waste liquid discharge channel 204 gradually shrinks from the detection chamber 203 to the waste liquid discharge channel 204, so as to reduce the flow rate of the liquid in the detection chamber 203.

[0069] See also Figure 5 and Figure 6 , respectively showing a three-dimensional structure diagram and a top view of the top cover plate 100 , wherein the top cover plate 100 is provided with a sample addition hole 101 and a waste liquid hole 102 , wherein the sample addition hole 101 is connected to the liquid storage tank 201 , and the waste liquid hole 102 is connected to the waste liquid discharge channel 204 .

[0070] See also Figures 7 to 9 ,in, Figure 7 It is a schematic diagram of the three-dimensional structure of the lower flow channel structure layer 300. Figure 8 It is a top view of the lower channel structure layer 300. Figure 9 A bottom view of the lower flow channel structure layer 300 is shown.

[0071] Specifically, the top cover plate 100 is used to close the open flow channels of the upper flow channel structure layer 200 and reserve external openings for the flow channels of the upper flow channel structure layer, and the bottom cover plate 400 (not shown separately) is used to close the open flow channels of the lower flow channel layer 300.

[0072] Specifically, the piezoelectric micropump includes a piezoelectric micropump channel and a piezoelectric film (not shown). The piezoelectric micropump channel is located in the upper channel structure layer 200 and the lower channel structure layer 300, and is connected to the liquid reservoir 201 and the liquid input channel 202 respectively. The piezoelectric film is located on the lower surface of the bottom cover plate 400 and is aligned with the piezoelectric micropump channel. The piezoelectric micropump is used to unidirectionally transmit liquid from the liquid reservoir 201 to the liquid input channel 202.

[0073] As an example, see Figure 4The lower surface of the upper channel structure layer 200 is provided with a first concave cavity 205 and a second concave cavity 206. The liquid reservoir 201 is connected to the first concave cavity 205 via a first through hole 207 penetrating the upper channel structure layer 200. The second concave cavity 206 is connected to the liquid input channel 202 via a second through hole 208 penetrating the upper channel structure layer. A first diaphragm 209 is placed in the first concave cavity (see the following). Figures 10 to 13 ); please refer back to Figure 7 and Figure 8 The upper surface of the lower flow channel structure layer 300 is provided with a third cavity 302 aligned with the first cavity 205 and a fourth cavity 303 aligned with the second cavity 206, and a second diaphragm (not shown) is placed in the fourth cavity 303; please refer back to Figure 9 A fifth cavity 304 is provided on the lower surface of the lower flow channel structure layer 300, in which a piezoelectric film (not shown) is placed, and a lower transmission flow channel 301, a sixth cavity 305 aligned with the third cavity 302, and a seventh cavity 306 aligned with the fourth cavity 303 are provided at the bottom of the fifth cavity 304. Both ends of the lower transmission flow channel 301 are connected with the sixth cavity 305 and the seventh cavity 306 respectively. The third cavity 302 is connected with the sixth cavity 305 through a third through hole 307 penetrating the lower flow channel structure layer 300, and the fourth cavity 303 is connected with the seventh cavity 306 through a fourth through hole 308 penetrating the lower flow channel structure layer 300.

[0074] Among them, the first through hole 207, the first concave cavity 205, the third concave cavity 302, the third through hole 307, the sixth concave cavity 305, the lower layer transmission channel 301, the fifth concave cavity 304, the second through hole 208, the second concave cavity 206, the fourth concave cavity 303, the fourth through hole 308 and the seventh concave cavity 306 together constitute the piezoelectric micropump channel.

[0075] In particular, the first through hole 207, the first concave cavity 205, the first diaphragm 209, the third concave cavity 302, the third through hole 307, and the sixth concave cavity 305 together constitute a first piezoelectric micropump one-way valve for unidirectionally transmitting liquid from the liquid reservoir 201 to the lower transmission channel 301. The second through hole 208, the second concave cavity 206, the second diaphragm, the fourth concave cavity 303, the fourth through hole 308, and the seventh concave cavity 306 together constitute a second piezoelectric micropump one-way valve for unidirectionally transmitting liquid from the lower transmission channel 301 to the liquid input channel 202. The first piezoelectric micropump one-way valve, the lower transmission channel 301, the fifth concave cavity 304, the second piezoelectric micropump one-way valve, and the piezoelectric film together constitute the piezoelectric micropump.

[0076] In this embodiment, the fifth cavity 304 and the piezoelectric film are circular as an example. In other embodiments, the fifth cavity 304 and the piezoelectric film may also be in other shapes, which should not overly limit the scope of protection of the present invention.

[0077] See also Figures 10 to 13 , which is a schematic diagram of the enlarged structure of the first piezoelectric micropump one-way valve, wherein: Figure 10 Shown is a three-dimensional diagram of the cross-sectional structure of the first piezoelectric micropump one-way valve (including the invisible part), Figure 11 Shown is a cross-sectional structural stereogram of the first piezoelectric micropump one-way valve (visible part), Figure 12 The figure shows an exploded structural diagram of the cross-sectional structure of the first piezoelectric micropump one-way valve. Figure 13 Shown is a schematic diagram of the exploded structure of the cross-sectional structure of the first piezoelectric micropump one-way valve at another angle.

[0078] Specifically, the internal flow channel of the first piezoelectric micropump one-way valve is composed of the first through hole 207, the first concave cavity 205, the third concave cavity 302, the third through hole 307 and the sixth concave cavity 305, and the internal flow channel of the second piezoelectric micropump one-way valve is composed of the second through hole 208, the second concave cavity 206, the fourth concave cavity 303, the fourth through hole 308 and the seventh concave cavity 306.

[0079] As an example, the opening area of ​​the first concave cavity 205 is larger than the opening area of ​​the third concave cavity 302, and the first diaphragm 209 includes a suspension portion 209a, which is suspended above the third concave cavity 302 and covers the bottom of the first through hole 207 to realize the one-way valve function, and the opening area of ​​the third concave cavity 302 is larger than the area of ​​the part of the suspension portion 209a suspended above the third concave cavity 302 to avoid the opening of the third concave cavity 302 being completely blocked by the suspension portion 209a and preventing the liquid from flowing out toward the third through hole 307.

[0080] As an example, a groove 210 surrounding or partially surrounding the first through hole 207 is provided at the bottom of the first cavity 205 to more effectively prevent liquid backflow, and a distance is provided between the groove 210 and the first through hole 207 .

[0081] As an example, at least one boss 309 is provided at the bottom of the third concave cavity 302. The boss's surface is lower than the top surface of the lower flow channel structure layer 300, and the boss 309 is located near one end of the anchoring portion 209a. The third concave cavity 302 is primarily used to provide deformation space for the first diaphragm 209. The boss 309 can buffer the deformation of the suspension portion 209a of the first diaphragm 209, preventing the suspension portion 209a from completely blocking the third through hole 307, thereby preventing the liquid from flowing out of the third through hole 307.

[0082] It should be pointed out that, in the second piezoelectric micropump one-way valve, the fourth cavity 303 located on the upper surface of the lower channel structure layer 300 can adopt the same structure as the first cavity 205 located on the lower surface of the upper channel structure layer 200, and the second cavity 206 located on the lower surface of the upper channel structure layer 200 can adopt the same structure as the third cavity 302 located on the upper surface of the lower channel layer 300, and the second diaphragm is placed in the fourth cavity 303 to achieve a one-way transmission direction opposite to that of the first piezoelectric micropump one-way valve.

[0083] As an example, the first diaphragm 209 and the second diaphragm are made of flexible materials, including but not limited to silicone, polydimethylsiloxane (PDMS) and other materials.

[0084] As an example, to enable the addition of different liquids and multi-liquid path switching, the microfluidic chip may include at least two sample loading ports, at least two liquid reservoirs, and at least two piezoelectric micropumps, with each liquid reservoir transmitting liquid unidirectionally to the detection chamber via a different piezoelectric micropump. In this embodiment, one detection chamber corresponds to three liquid reservoirs. In other embodiments, the number of liquid reservoirs may not be limited to three, and the number of detection chambers may not be limited to one. This should not unduly limit the scope of the present invention.

[0085] Specifically, the top cover plate 100, the upper flow channel structure layer 200 and the lower flow channel structure layer 300 can be made of transparent or opaque solid materials, including but not limited to glass, silicon, plastic and other materials. The bottom cover plate 400 is preferably made of a flexible material so that it can bend with the bending of the piezoelectric film. Of course, the bottom cover plate 400 can also be made of a thinner hard material, which can also play a certain deformation role, such as using a hard plastic with a thickness of less than 2 mm. The top cover plate 100, the upper flow channel structure layer 200, the lower flow channel structure layer 300 and the bottom cover plate 400 can be assembled and connected by gluing (such as double-sided tape), chemical bonding, hot pressing bonding and the like.

[0086] Specifically, the working principle of the piezoelectric micropump is as follows:

[0087] (1) When the piezoelectric film bends downward under the action of the electrical signal, the volume of the piezoelectric micropump flow channel increases, and the third concave cavity 302 of the first piezoelectric micropump one-way valve generates a negative pressure, causing the suspended portion of the first diaphragm 209 to move toward the third concave cavity 302 and separate from the bottom of the first through hole 207. The liquid in the liquid reservoir 201 flows from the first through hole 207 into the third concave cavity 302 and then into the lower transmission channel 301 through the third through hole 307. At the same time, the fourth through hole 308 of the second piezoelectric micropump one-way valve also generates a negative pressure, causing the suspended portion of the second diaphragm to be in close contact with the outlet of the fourth through hole 308, and preventing the liquid from flowing into the second concave cavity 206 through the fourth through hole 308.

[0088] (2) When the piezoelectric film bends upward under the action of the electrical signal, causing the volume of the piezoelectric micropump flow channel to decrease, the third concave cavity 302 of the first piezoelectric micropump one-way valve generates positive pressure, causing the suspended portion 209a of the first diaphragm 209 to cling to the bottom of the first through hole 207, preventing liquid backflow. At the same time, the fourth through hole 308 of the second piezoelectric micropump one-way valve also generates positive pressure, causing the suspended portion of the second diaphragm to separate from the outlet of the fourth through hole 308. The liquid in the lower transmission channel 301 flows through the fourth through hole 308 to the second concave cavity 206, and then flows through the second through hole 208 to the liquid input channel 202, and finally enters the detection chamber 203.

[0089] The microfluidic chip of this embodiment integrates a piezoelectric micropump, enabling active fluid control from the liquid reservoir to the detection chamber and preventing backflow. When the microfluidic chip includes multiple liquid reservoirs and multiple piezoelectric micropumps, multiple fluid path switching can also be achieved. The microfluidic chip of the present invention can be applied to a variety of reactions, including but not limited to immunosorbent reactions and gene probe reactions. Based on the desired reaction, the desired sample and reagent can be added to the liquid reservoir.

[0090] Example 2

[0091] In this embodiment, the microfluidic chip described in the first embodiment is used, and the detection chamber of the microfluidic chip is coated with an antibody for detecting a specific substance to be detected to detect the content of the substance to be detected in a liquid sample.

[0092] As an example, the microfluidic chip can be used by injecting different samples or reagents into different reservoirs through the sample injection holes before the experiment begins. The piezoelectric micropumps are then operated sequentially to pump the samples or reagents into the detection chambers and complete the reaction.

[0093] Specifically, by using multiple sample addition wells, multiple liquids can be added sequentially. For example, the first liquid reservoir can deliver the sample liquid to the detection chamber. After a certain amount of sample liquid has been delivered, the second liquid reservoir can deliver a certain amount of detection liquid to the detection area to generate a signal. Then, the third liquid reservoir can deliver a certain amount of cleaning liquid to the detection chamber to wash away unreacted liquid, and the waste liquid is discharged through the waste liquid well.

[0094] In summary, the microfluidic chip of the present invention integrates a piezoelectric micropump, which can achieve active fluid control from the liquid reservoir to the detection chamber and prevent backflow. When the microfluidic chip includes multiple liquid reservoirs and multiple piezoelectric micropumps, multiple liquid path switching can also be achieved. The microfluidic chip of the present invention can be applied to a variety of reactions, including but not limited to immunosorbent reactions, gene probe reactions, etc., and the required samples and reagents can be added to the liquid reservoir based on the required reaction. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0095] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A microfluidic chip, characterized in that: include: An upper flow channel structure layer, wherein the upper surface of the upper flow channel structure layer is provided with a liquid storage tank, a liquid input flow channel, a detection chamber and a waste liquid discharge flow channel, and the two ends of the detection chamber are respectively connected to the liquid input flow channel and the waste liquid discharge flow channel; A top cover plate is located above the upper flow channel structure layer, and is provided with a sample addition hole and a waste liquid hole in the top cover plate, wherein the sample addition hole is connected to the liquid reservoir, and the waste liquid hole is connected to the waste liquid discharge flow channel; A lower flow channel structure layer, located below the upper flow channel structure layer; A bottom cover plate, located below the lower flow channel structure layer; A piezoelectric micropump, comprising a piezoelectric micropump flow channel and a piezoelectric film, wherein the piezoelectric micropump flow channel is located in the upper flow channel structure layer and the lower flow channel structure layer and is in communication with the liquid reservoir and the liquid input flow channel, respectively; the piezoelectric film is located on the lower surface of the bottom cover plate and is aligned with the piezoelectric micropump flow channel; the piezoelectric micropump is used to unidirectionally transport liquid from the liquid reservoir to the liquid input flow channel; A first concave cavity is provided on the lower surface of the upper flow channel structure layer, the liquid reservoir is connected to the first concave cavity via a first through hole penetrating the upper flow channel structure layer, and a first diaphragm is placed in the first concave cavity; The upper surface of the lower flow channel structure layer is provided with a third cavity aligned with the first cavity; A sixth concave cavity is provided on the lower surface of the lower flow channel structure layer, which is aligned with the third concave cavity, and the third concave cavity is connected to the sixth concave cavity via a third through hole penetrating the lower flow channel structure layer; Wherein, the first through hole, the first concave cavity, the first diaphragm, the third concave cavity, the third through hole and the sixth concave cavity together constitute a first piezoelectric micro-pump one-way valve; The opening area of ​​the first concave cavity is larger than the opening area of ​​the third concave cavity. The first diaphragm includes a suspension portion, which is suspended above the third concave cavity and covers the bottom of the first through hole. The opening area of ​​the third concave cavity is larger than the area of ​​the portion of the suspension portion suspended above the third concave cavity. The first diaphragm is made of flexible material.

2. The microfluidic chip according to claim 1, wherein: The lower surface of the upper flow channel structure layer is further provided with a second concave cavity, and the second concave cavity is connected to the liquid input flow channel via a second through hole penetrating the upper flow channel structure layer; The upper surface of the lower flow channel structure layer is further provided with a fourth cavity aligned with the second cavity, and a second diaphragm is placed in the fourth cavity. A fifth cavity is provided on the lower surface of the lower flow channel structure layer, a piezoelectric film is placed in the fifth cavity, and the sixth cavity is provided at the bottom of the fifth cavity; a lower transmission flow channel and a seventh cavity aligned with the fourth cavity are also provided at the bottom of the fifth cavity, the two ends of the lower transmission flow channel are respectively connected to the sixth cavity and the seventh cavity, and the fourth cavity is connected to the seventh cavity via a fourth through hole penetrating the lower flow channel structure layer; The second through hole, the second cavity, the second diaphragm, the fourth cavity, the fourth through hole and the seventh cavity together constitute a second piezoelectric micro-pump one-way valve. The first piezoelectric micropump one-way valve, the lower transmission channel, the fifth cavity, the second piezoelectric micropump one-way valve and the piezoelectric film together constitute the piezoelectric micropump.

3. The microfluidic chip according to claim 1, wherein: A groove surrounding the first through hole is formed at the bottom of the first cavity.

4. The microfluidic chip according to claim 1, wherein: At least one boss is provided at the bottom of the third cavity, the surface of the boss is lower than the top surface of the lower flow channel structure layer, and the boss is close to one end where the suspension portion is anchored.

5. The microfluidic chip according to claim 2, characterized in that: The second diaphragm is made of flexible material.

6. The microfluidic chip according to claim 1 or 2, characterized in that: The material of the top cover plate, the upper flow channel structure layer and the lower flow channel structure layer includes any one of glass, silicon and plastic. The bottom cover plate adopts a flexible material, or the bottom cover plate adopts a hard plastic with a thickness of less than 2 mm.

7. The microfluidic chip according to claim 1 or 2, characterized in that: The top cover plate, the upper flow channel structure layer, the lower flow channel structure layer and the bottom cover plate are connected by any one of gluing, chemical bonding and hot pressing bonding.

8. The microfluidic chip according to claim 1 or 2, characterized in that: The microfluidic chip comprises at least two sample addition holes, at least two liquid storage tanks and at least two piezoelectric micro pumps. Each liquid storage tank transmits liquid to the detection chamber in a unidirectional manner through a different piezoelectric micro pump.

9. The microfluidic chip according to claim 1, characterized in that: The microfluidic chip includes at least two detection chambers.

10. The microfluidic chip according to claim 1 or 2, characterized in that: The microfluidic chip is used for immunoadsorption reaction or gene probe reaction.

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