Liquid injection device, liquid injection method and micro-fluidic system

Abstract

A liquid injection device, a liquid injection method, and a micro-fluidic system. The liquid injection device (100) has a liquid injection mode and a liquid supplement mode; in the liquid injection mode, a transmission liquid is injected into a first cavity (111), and then the transmission liquid acts on a first surface (311) and drives, by means of a first connecting part (33), a second sliding part (32) to slide, so that a reaction liquid in a fourth cavity (212) or the downstream section of the fourth cavity (212) is injected into a reaction device (200); and in the liquid supplementing mode, the transmission liquid is injected into a second cavity (112), and then the transmission liquid acts on a second surface (312) and drives, by means of the first connecting part (33), the second sliding part (32) to slide, so that the fourth cavity (212) or the downstream section of the fourth cavity (212) accommodates the injected reaction liquid. The area of the transmission liquid acting on the first surface (311) is greater than the area of the transmission liquid acting on the second surface (312), so that slow liquid injection and rapid liquid supplementation can be realized, and the slow liquid injection is beneficial to accurately and slightly controlling the liquid injection amount.

Description

Liquid injection device, liquid injection method and microfluidic system Technical Field

[0001] The present application relates to the field of liquid injection, and in particular to a liquid injection device, a liquid injection method and a microfluidic system. Background Art

[0002] When injecting liquids in fields such as biology, medicine, and chemical engineering, precise and minute control of the injection volume and speed is often required to ensure uniform quantitative distribution of the injected liquid. Slightly larger errors can directly impact test results. For example, microfluidic chips integrate conventional biochemical reactions into a chip measuring just a few square centimeters. For microfluidic chips, precise injection of microliter-scale liquids is a fundamental step before sample and reagent mixing and biochemical reactions can complete, directly impacting the chip's detection accuracy.

[0003] However, in the related art, the injection pump used to achieve trace liquid injection is expensive and has low adjustment accuracy.

[0004] Summary of the Invention

[0005] In view of this, it is necessary to provide a liquid injection device and method.

[0006] In addition, it is also necessary to provide a microfluidic system having the above-mentioned liquid injection device.

[0007] In a first aspect, the present application provides a liquid injection device for connecting to at least one reaction device. The liquid injection device includes a first container, a second container, and a first connector. The first container defines a first accommodating chamber. The second container defines a second accommodating chamber. The first connector includes a first sliding portion, a second sliding portion, and a first connector connected between the first and second sliding portions. The first sliding portion includes a first surface and a second surface disposed opposite each other, with the first connector connected to the second surface. The first sliding portion slides within the first accommodating chamber and divides the first accommodating chamber into a first cavity and a second cavity, each isolated from each other. The first surface faces the first cavity, and the second surface faces the second cavity. Both the first cavity and the second cavity are used to hold transmission liquid. The second sliding portion slides within the second accommodating chamber and divides the second cavity into a third cavity and a fourth cavity, each isolated from each other. The fourth cavity or a downstream section of the fourth cavity is used to hold reaction liquid supplied to the reaction device. The liquid injection device has an injection mode and a refill mode. In the injection mode, the transmission fluid injected into the first cavity acts on the first surface and drives the second sliding portion to slide via the first connecting portion, thereby injecting the reaction fluid in the fourth cavity or the downstream section of the fourth cavity into the reaction device. In the replenishment mode, the transmission fluid injected into the second cavity acts on the second surface and drives the second sliding portion to slide via the first connecting portion, thereby accommodating the injected reaction fluid in the fourth cavity or the downstream section of the fourth cavity. The area of ​​the transmission fluid acting on the first surface is greater than the area of ​​the transmission fluid acting on the second surface.

[0008] A second aspect of the present application provides a liquid injection method applied to the above liquid injection device, comprising the following steps: switching the liquid injection device to the liquid injection mode; injecting the transmission liquid into the first cavity, causing the transmission liquid to act on the first surface and drive the second sliding part to slide through the first connecting part, so that the reaction liquid in the fourth cavity or the downstream section of the fourth cavity is injected into the reaction device; switching the liquid injection device to the liquid replenishment mode; injecting the transmission liquid into the second cavity, causing the transmission liquid to act on the second surface and drive the second sliding part to slide through the first connecting part, so that the fourth cavity or the downstream section of the fourth cavity accommodates the reaction liquid injected therein.

[0009] A third aspect of the present application provides a microfluidic system comprising a reaction device, wherein the reaction device is a microfluidic chip. The microfluidic system further comprises the liquid injection device as described above, wherein the fourth cavity of the liquid injection device is in communication with the microfluidic chip.

[0010] The present application constructs a liquid injection device through conventional liquid path components, which has a simple structure and is conducive to reducing costs. When the transmission liquid drives the first sliding part to slide in the first accommodating chamber in the injection mode, the transmission liquid acts on the first surface; when the transmission liquid drives the first sliding part to slide in the opposite direction in the first accommodating chamber in the replenishment mode, the transmission liquid acts on the second surface. The area of ​​the transmission liquid acting on the first surface in the injection mode is larger than the area of ​​the transmission liquid acting on the second surface in the replenishment mode, so that the sliding speed of the second sliding part in the injection mode is smaller than the sliding speed of the second sliding part in the replenishment mode. Therefore, the present application can realize slow injection and fast replenishment. Slow injection is conducive to precise and micro-control of the injection volume, while fast replenishment is conducive to improving work efficiency. When it is necessary to further slow down the injection speed, the effective area of ​​the transmission liquid in the injection mode can be further reduced. Therefore, the present application can adjust the injection speed and injection volume according to actual needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG1 is a schematic diagram of the three-dimensional structure of a liquid injection device provided in one embodiment of the present application.

[0012] FIG2 is a schematic diagram showing the connection of various components in the liquid injection device shown in FIG1 .

[0013] FIG3 is a schematic diagram of liquid flow direction of the liquid injection device shown in FIG2 in the liquid injection mode.

[0014] FIG4 is a schematic diagram of liquid flow direction of the liquid injection device shown in FIG2 in a liquid infusion mode.

[0015] FIG5 is a schematic diagram showing the connection of various components in a liquid injection device in other embodiments.

[0016] FIG6 is a schematic diagram showing the connection of various components in the liquid injection device in some other embodiments.

[0017] FIG7 is a schematic diagram showing the connections of the components of a liquid injection device according to another embodiment of the present application.

[0018] FIG8 is a flow chart of a liquid injection method provided in one embodiment of the present application.

[0019] FIG9 is a module architecture diagram of a microfluidic system provided in one embodiment of the present application.

[0020] Description of Main Component Symbols Microfluidic System 1 First Container 10 First Accommodation Chamber 11 First Inlet 12 Second Inlet 13 Second Accommodation Chamber 20 Second Accommodation Chamber 21 Outlet 22, 402 Third Inlet 23, 403 First Connector 30 First Sliding Portion 31 Second Sliding Portion 32 First Connector 33 Transmission Liquid Source 40 First Storage Module 41 Second Storage Module 42 Reaction Liquid Source 50 Power Source 60 First Pipe 61 Second Pipe 62 Third Pipe 63 Fourth Pipe 64 First Valve 65 Second Valve 70 Fifth Pipe 71 Bifurcation 71a Third Valve 80 Sixth Pipe 81 Fixing Frame 90 First Baffle 91 Second Baffle 92 Third Baffle 93Liquid injection device 100, 100a First cavity 111 Second cavity 112 Reaction device 200 Third cavity 211 Third accommodating member 300 First surface 311 Second surface 312 Third surface 321 Fourth surface 322 First connecting section 331 Second connecting section 332 Fourth accommodating member 400 Third sliding portion 501 Fourth sliding portion 502 Second connecting portion 503 Fifth cavity 3011 Sixth cavity 3012 Seventh cavity 4011 Eighth cavity 4012 Fifth surface 5011 Sixth surface 5012 Seventh surface 5021 Eighth surface 5022 Liquid injection mode M1 Liquid replenishment mode M2 ​​First direction X Primary injection mechanism L1 Secondary injection mechanism L2 Connection port O

[0021] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present application in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0023] It should be noted that when a component is referred to as being "fixed to" or "mounted on" another component, it may be directly on the other component or there may be a central component. When a component is referred to as being "disposed on" another component, it may be directly on the other component or there may be a central component. As used herein, the term "and / or" includes all and any combinations of one or more of the relevant listed items.

[0024] It should be noted that, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in an order different from that in the flowchart. The method disclosed in the embodiments of the present application includes one or more steps or actions for implementing the method. The method steps and / or actions may be interchangeable with each other without departing from the scope of the claims. Unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the claims.

[0025] Please refer to Figures 1 and 2. One embodiment of the present application provides a liquid injection device 100 for connecting to at least one reaction device 200. Please refer to Figures 3 and 4. The liquid injection device 100 can switch between an injection mode M1 and a rehydration mode M2. In the injection mode M1, the liquid injection device 100 injects the reaction liquid into the reaction device 200. The rehydration mode M2 ​​is that the liquid injection device 100 replenishes the reaction liquid to facilitate the next injection of the reaction liquid. In some embodiments, the reaction device 200 is a microfluidic chip, and can also be a reaction device for chemical reactions in the fields of biology, medicine, chemical industry, etc.

[0026] As shown in FIG. 1 and FIG. 2 , the liquid injection device 100 includes a first container 10 , a second container 20 , a first connecting member 30 , a transmission liquid source 40 , and a reaction liquid source 50 .

[0027] Both the first container 10 and the second container 20 are hollow structures. The first container 10 defines a first accommodating cavity 11, and the second container 20 defines a second accommodating cavity 21. The first connector 30 includes a first sliding portion 31, a second sliding portion 32, and a first connecting portion 33 connected between the first and second sliding portions 31, 32. The first sliding portion 31 slides within the first accommodating cavity 11, and the second sliding portion 32 slides within the second accommodating cavity 21. The first sliding portion 31 includes a first surface 311 and a second surface 312 disposed opposite each other, and the areas of the first and second surfaces 311, 312 may be the same. One end of the first connecting portion 33 is fixed to a portion of the second surface 312. The second sliding portion 32 includes a third surface 321 and a fourth surface 322 disposed opposite each other, and the areas of the third and fourth surfaces 321, 322 may be the same. The other end of the first connecting portion 33 is fixed to the third surface 321. In some embodiments, the first and second sliding portions 31, 32 may both be plunger structures, with the first connecting portion 33 being a plunger rod. The first connecting portion 33 may be made of a rigid material, thereby increasing its service life.

[0028] The first sliding portion 31 divides the first accommodating chamber 11 into a first cavity 111 and a second cavity 112, which are isolated from each other. The first surface 311 faces the first cavity 111, while the second surface 312 faces the second cavity 112. The first cavity 111 is farther from the second accommodating member 20 than the second cavity 112. One end of the first connecting portion 33 is fixed to the second surface 312, allowing it to pass through the second cavity 112. Both the first cavity 111 and the second cavity 112 are used to hold transmission fluid. The sizes of the first and second cavities 111 and 112 are variable. For example, when the first sliding portion 31 slides in the first accommodating cavity 11 along the first direction X (i.e., toward the second accommodating member 20), the space of the first cavity 111 becomes larger and the space of the second cavity 112 becomes smaller; for another example, when the first sliding portion 31 slides in the first accommodating cavity 11 along the opposite direction of the first direction X (i.e., away from the second accommodating member 20), the space of the first cavity 111 becomes smaller and the space of the second cavity 112 becomes larger.

[0029] The second sliding portion 32 divides the second accommodating chamber 21 into a third cavity 211 and a fourth cavity 212, which are isolated from each other. The third surface 321 faces the third cavity 211, while the fourth surface 322 faces the fourth cavity 212. The fourth cavity 212 is further away from the first accommodating member 10 than the third cavity 211. Because one end of the first connecting portion 33 is fixed to the third surface 321, the first connecting portion 33 can pass through the third cavity 211. The third cavity 211 contains air, while the fourth cavity 212 is used to hold the reaction liquid. The sizes of the third and fourth cavities 211, 212 are variable. For example, when the second sliding portion 32 slides within the second accommodating chamber 21 along the first direction X, the space in the third cavity 211 increases, while the space in the fourth cavity 212 decreases. Alternatively, when the second sliding portion 32 slides within the second accommodating chamber 21 in a direction opposite to the first direction X, the space in the third cavity 211 decreases, while the space in the fourth cavity 212 increases.

[0030] The first container 10 is further provided with a first inlet 12 and a second inlet 13. The first inlet 12 communicates with the first cavity 111, and the second inlet 13 communicates with the second cavity 112. The first inlet 12 and the second inlet 13 are also connected to a transmission fluid source 40, respectively. The transmission fluid source 40 is used to contain transmission fluid. The transmission fluid in the transmission fluid source 40 can be injected into the first cavity 111 through the first inlet 12 and can also be injected into the second cavity 112 through the second inlet 13.

[0031] The second container 20 further defines an outlet 22 and a third inlet 23, both of which communicate with the fourth chamber 212. The outlet 22 is configured to communicate with at least one reaction device 200, allowing the reaction liquid in the fourth chamber 212 to be injected into the reaction device 200 via the outlet 22. The third inlet 23 is configured to communicate with a reaction liquid source 50. The reaction liquid source 50 is configured to hold the reaction liquid, allowing the reaction liquid in the reaction liquid source 50 to be injected into the fourth chamber 212 via the third inlet 23. In FIG2 , the outlet 22 communicates with only one reaction device 200. As shown in FIG5 , when the outlet 22 communicates with multiple reaction devices 200, the multiple reaction devices 200 can be arranged in parallel, thereby improving injection efficiency and reaction throughput.

[0032] During operation, the first and second cavities 111 and 112 can each be filled with a transmission liquid, which can be supplied from a transmission liquid source 40. As shown in FIG3 , when the liquid injection device 100 is in injection mode M1, transmission liquid from the transmission liquid source 40 continues to be injected into the first cavity 111 via the first inlet 12. The pressure within the first cavity 111 increases, and the transmission liquid within the first cavity 111 acts on the first surface 311, driving the first sliding portion 31 to slide along the first direction X within the first accommodating cavity 11. This in turn drives the second sliding portion 32 to slide along the first direction X within the second accommodating cavity 21 via the first connecting portion 33, resulting in a smaller space within the fourth cavity 212 and an increased pressure. Consequently, the reaction liquid within the fourth cavity 212 can be squeezed and injected into the reaction device 200. In this application, the transmission liquid driving the first sliding portion 31 to slide along the first direction X can specifically be the transmission liquid pushing the first sliding portion 31 to slide along the first direction X. The first connecting portion 33 drives the second sliding portion 32 to slide along the first direction X. Specifically, the first connecting portion 33 pushes the second sliding portion 32 to slide along the first direction X.

[0033] As shown in FIG4 , when the liquid injection device 100 is in the liquid replenishment mode M2, the transmission liquid from the transmission liquid source 40 is injected into the second cavity 112 via the second inlet 13. The pressure within the second cavity 112 increases. Therefore, the transmission liquid within the second cavity 112 acts on the second surface 312 and drives the first sliding portion 31 to slide within the first accommodating cavity 11 in the direction opposite to the first direction X. Furthermore, the first connecting portion 33 drives the second sliding portion 32 to slide within the second accommodating cavity 21 in the direction opposite to the first direction X, thereby increasing the volume of the fourth cavity 212 and reducing the pressure. Therefore, the reaction liquid from the reaction liquid source 50 can be injected into the fourth cavity 212 via the third inlet 23, thereby replenishing the reaction liquid within the fourth cavity 212. In this application, the transmission liquid drives the first sliding portion 31 to slide in the opposite direction, specifically, the transmission liquid can push the first sliding portion 31 to slide in the opposite direction. The first connecting portion 33 drives the second sliding portion 32 to slide in the opposite direction, specifically, the first connecting portion 33 can pull the second sliding portion 32 to slide in the opposite direction.

[0034] Among them, the transmission liquid refers to a working medium that can transfer kinetic energy to the first sliding part 31, thereby driving the first sliding part 31 to slide. The transmission liquid can be transmission oil or any other suitable working medium. The reaction liquid can refer to a reaction reagent that participates in a chemical reaction. The transmission liquid source 40 and the reaction liquid source 50 can be containers suitable for storing and containing liquids, respectively. For example, the transmission liquid source 40 is an oil tank for containing transmission oil, and the reaction liquid source 50 is a reagent pack for containing reaction reagents. This application is not limited to this. In other embodiments, the transmission liquid source 40 and the reaction liquid source 50 can be components independent of the liquid injection device 100. When in use, the transmission liquid source 40 and the reaction liquid source 50 are respectively connected to the corresponding pipes of the liquid injection device 100.

[0035] The present application utilizes conventional fluid path components to construct a liquid injection device 100, resulting in a simple structure and reduced costs. In the injection mode M1, when the transmission liquid drives the first sliding portion 31 to slide within the first accommodating chamber 11 along the first direction X, the transmission liquid acts on the first surface 311. In the refill mode M2, when the transmission liquid drives the first sliding portion 31 to slide within the first accommodating chamber 11 in the opposite direction of the first direction X, the transmission liquid acts on the second surface 312. Because the first connecting portion 33 is connected to the second surface 312, the transmission liquid actually acts only on the area of ​​the second surface 312 excluding the first connecting portion 33. This means that the area affected by the transmission liquid in the injection mode M1 is greater than the area affected by the transmission liquid in the refill mode M2. Therefore, the sliding speed of the first sliding portion 31 in the injection mode M1 is less than the sliding speed of the first sliding portion 31 in the refill mode M2. Since the sliding speed of the first sliding portion 31 is equal to the sliding speed of the second sliding portion 32, the sliding speed of the second sliding portion 32 in the injection mode M1 is less than that in the refill mode M2. Therefore, the present application can achieve slow injection and rapid fluid replenishment. Slow injection is conducive to precise and minute control of the injection volume, while rapid fluid replenishment is conducive to improving work efficiency. Through rapid fluid replenishment, the present application can achieve microliter-level fluid injection for up to several hours. When it is necessary to further slow down the injection speed, the effective area of ​​the transmission liquid under the injection mode M1 can be further increased (for example, increasing the area of ​​the first surface 311). When it is necessary to further speed up the fluid replenishment speed, the effective area of ​​the transmission liquid under the fluid replenishment mode M2 ​​can be further reduced (for example, increasing the diameter of the part of the first connecting portion 33 connected to the second surface 312). Therefore, the present application can adjust the injection speed and fluid replenishment speed according to actual needs.

[0036] Among them, as shown in Figures 1 and 2, the diameter of the end of the first connecting part 33 close to the first sliding part 31 (that is, the diameter of the part of the first connecting part 33 connected to the second surface 312) is larger than the diameter of the end of the first connecting part 33 close to the second sliding part 32. That is, the first connecting part 33 can be a special-shaped rod. In this way, while ensuring that the effective area of ​​the transmission liquid is small under the fluid replenishment mode M2, it can also avoid the overall increase of the second accommodating chamber 21 due to the need to adapt to the larger diameter of the first connecting part 33, resulting in an increase in the volume or weight of the liquid injection device 100. In other embodiments, the first connecting part 33 can also be set to have the same diameter from the end close to the first sliding part 31 to the end close to the second sliding part 32.

[0037] In some embodiments, the liquid injection device 100 further includes a power source 60, a first valve 65, a first pipe 61, a second pipe 62, a third pipe 63, and a fourth pipe 64. The first valve 65 has four interfaces (not shown), which are respectively connected to one end of the first pipe 61, one end of the second pipe 62, one end of the third pipe 63, and one end of the fourth pipe 64. The other end of the first pipe 61 away from the first valve 65 and the other end of the second pipe 62 away from the first valve 65 are both connected to the transmission liquid source 40. The other end of the third pipe 63 away from the first valve 65 is connected to the first inlet 12, and the other end of the fourth pipe 64 away from the first valve 65 is connected to the second inlet 13. The power source 60 is provided on the first pipe 61.

[0038] As shown in FIG3 , the first valve 65 connects the first conduit 61 to the third conduit 63 and the second conduit 62 to the fourth conduit 64, thereby switching the liquid injection device 100 to the injection mode M1. Therefore, in the injection mode M1, the power source 60 can drive the transmission liquid in the transmission liquid source 40 through the first conduit 61 and the third conduit 63 and into the first inlet 12. Specifically, the power source 60 provides power for the transmission liquid to flow into the first cavity 111. After the transmission liquid enters the first cavity 111, it drives the first sliding portion 31 to slide along the first direction X within the first accommodating chamber 11, causing the space in the second cavity 112 to decrease and forcing the transmission liquid in the second cavity 112 back into the transmission liquid source 40 through the fourth conduit 64 and the second conduit 62. As shown in FIG4 , the first valve 65 connects the first conduit 61 to the fourth conduit 64 and the second conduit 62 to the third conduit 63, thereby switching the liquid injection device 100 to the liquid replenishment mode M2. Therefore, in fluid replenishment mode M2, the power source 60 can drive the transmission fluid in the transmission fluid source 40 through the first conduit 61 and the fourth conduit 64 into the second inlet 13. Specifically, the power source 60 provides power for the transmission fluid to flow into the second cavity 112. After entering the second cavity 112, the transmission fluid drives the first sliding portion 31 to slide within the first accommodating cavity 11 in a direction opposite to the first direction X, thereby reducing the volume of the first cavity 111 and forcing the transmission fluid within the first cavity 111 back into the transmission fluid source 40 through the third conduit 63 and the second conduit 62. In some embodiments, the first valve 65 can be a two-position, four-way solenoid valve, which switches the liquid injection device 100 between the fluid replenishment mode M1 and the fluid replenishment mode M2 ​​by shifting the valve core.

[0039] Furthermore, the transmission liquid source 40 is divided into a first storage module 41 and a second storage module 42, which are independent of each other. The end of the first pipe 61 facing away from the first valve 65 is connected to the first storage module 41, and the end of the second pipe 62 facing away from the first valve 65 is connected to the second storage module 42. As shown in FIG3 , when the liquid injection device 100 is in injection mode M1, the power source 60 drives the transmission liquid in the first storage module 41 into the first inlet 12, while the transmission liquid in the second cavity 112 returns to the second storage module 42. As shown in FIG4 , when the liquid injection device 100 is in refill mode M2, the power source 60 drives the transmission liquid in the first storage module 41 into the second inlet 13, while the transmission liquid in the first cavity 111 returns to the second storage module 42.

[0040] Among them, the power source 60 can be various types of pumps for driving liquid movement, such as a syringe pump, a plunger pump, a diaphragm pump, a gear pump, and a peristaltic pump. In some embodiments, when the liquid injection device 100 is in the injection mode M1, the pumping speed of the power source 60 is less than the pumping speed of the power source 60 when the liquid injection device 100 is in the rehydration mode M2, that is, when the liquid injection device 100 is in the injection mode M1, the flow rate of the power source 60 is less than the flow rate of the power source 60 when the liquid injection device 100 is in the rehydration mode M2. Therefore, the flow rate of the transmission liquid in the first storage module 41 entering the first inlet 12 is less than the flow rate of the transmission liquid in the first storage module 41 entering the second inlet 13. Therefore, the injection speed can be further reduced to facilitate precise and micro-control of the injection amount. Specifically, the area of ​​the transmission liquid acting on the first surface 311 is defined as S1 (m 2 ), the area of ​​the transmission liquid acting on the second surface 312 is S2 (m 2 ), the flow rate of power source 60 in injection mode M1 is Q1 (m3 / s), and the flow rate of power source 60 in refill mode M2 ​​is Q2 (m3 / s). Therefore, the sliding speed of the second sliding portion 32 in injection mode M1 is V1 = Q1 / S1, and the sliding speed of the second sliding portion 32 in refill mode M2 ​​is V2 = Q2 / S2. Calculation shows that the ratio of the injection speed to the refill speed is V1 / V2 = Q1S2 / Q2S1. Therefore, reducing the flow rate of power source 60 in injection mode M1 can further reduce the injection speed. Power source 60 is a bidirectional variable pump. Adjusting the angle of the swash plate can change the pump's output flow rate and pressure, thereby varying the pumping speed. In other embodiments, the pumping speed of the power source 60 when the liquid injection device 100 is in the injection mode M1 is equal to the pumping speed of the power source 60 when the liquid injection device 100 is in the refill mode M2. That is, the flow rate of the power source 60 when the liquid injection device 100 is in the injection mode M1 is equal to the flow rate of the power source 60 when the liquid injection device 100 is in the refill mode M2. Therefore, the flow rate of the transmission fluid in the first storage module 41 entering the first inlet 12 is equal to the flow rate of the transmission fluid in the first storage module 41 entering the second inlet 13. Because the effective area of ​​the transmission fluid in the injection mode M1 is smaller than the effective area of ​​the transmission fluid in the refill mode M2, the same pumping speed can still achieve slow injection and fast refill. Furthermore, since frequent adjustment of the pumping speed is not required, operation is simplified (in this case, the ratio of the injection speed to the refill speed, V1 / V2 = S2 / S1 > 1).

[0041] Furthermore, the area of ​​the fourth surface 322 is defined as S3 (m 2), the liquid flow rate injected into the reaction device 200 through the outlet 22 in the injection mode M2 ​​is Q3 (m3 / s). Therefore, the flow rate reduction ratio Q3 / Q2 = (V1×S3) / (V1×S1) = S3 / S1. Therefore, the area of ​​the fourth surface 322 can be set smaller than that of the first surface 311, thereby further reducing the injection speed. Furthermore, the first connecting portion 33 is configured as a shaped rod, which not only helps reduce the overall volume of the second accommodating chamber 21, but also helps reduce the area of ​​the fourth surface 322.

[0042] In some embodiments, the liquid injection device 100 further includes a fifth conduit 71 connecting the outlet 22 and the reaction device 200, a second valve 70 disposed on the fifth conduit 71, a sixth conduit 81 connecting the third inlet 23 and the reaction liquid source 50, and a third valve 80 disposed on the sixth conduit 81. As shown in FIG3 , when the liquid injection device 100 is in the liquid injection mode M1, the second valve 70 connects the outlet 22 and the reaction device 200, allowing the reaction liquid in the fourth cavity 212 to be injected into the reaction device 200. At this time, the third valve 80 disconnects the third inlet 23 from the reaction liquid source 50. As shown in FIG4 , when the liquid injection device 100 is in the liquid replenishment mode M2, the third valve 80 connects the third inlet 23 and the reaction liquid source 50, allowing the reaction liquid in the reaction liquid source 50 to be injected into the fourth cavity 212 through the third inlet 23. At this time, the second valve 70 disconnects the outlet 22 from the reaction device 200. In some embodiments, both the second valve 70 and the third valve 80 are one-way valves. The second valve 70 only allows the reaction liquid to flow from the outlet 22 to the reaction device 200 and prevents the reaction liquid from flowing back from the reaction device 200 to the outlet 22. The third valve 80 only allows the reaction liquid to flow from the reaction liquid source 50 to the third inlet 23 and prevents the reaction liquid from flowing back from the third inlet 23 to the reaction liquid source 50.

[0043] As shown in FIG5 , in other embodiments, the outlet 22 of the fourth chamber 212 is connected to multiple reaction devices 200. Specifically, the tail of the fifth conduit 71 can be provided with multiple bifurcations 71 a to respectively connect to the multiple reaction devices 200. In this case, a second valve 70 can be provided upstream of each bifurcations 71 a, i.e., there can be multiple second valves 70.

[0044] As shown in FIG6 , in some other embodiments, the structure of the first connector 30 can also be modified to connect multiple reaction devices 200. Specifically, the first connector 30 includes a first sliding portion 31, multiple second sliding portions 32, and a first connector 33. The first connector 33 includes a first connecting subsection 331 and multiple second connecting subsections 332. FIG6 shows that the first connector 33 includes two second connecting subsections 332. Each second connecting subsection 332 is connected to the first connecting subsection 331. The first connecting subsection 331 is connected to the first sliding portion 31, and each second connecting subsection 332 is connected to a second sliding portion 32, i.e., each second sliding portion 32 corresponds to a second connecting subsection 332. Since the second sliding portion 32 is slidably disposed within the second accommodating chamber 21, this embodiment includes multiple second accommodating chambers 21, and the outlet 22 corresponding to each second accommodating chamber 21 is connected to a reaction device 200. Among them, although this application only shows a schematic diagram of the liquid flow direction of the liquid injection device 100 shown in Figure 2 in the injection mode M1 and the replenishment mode M2 ​​(i.e., Figures 3 and 4), the liquid flow direction of the liquid injection device 100 in Figures 5 and 6 in the injection mode M1 and the replenishment mode M2 ​​can also be easily derived based on Figures 3 and 4.

[0045] The liquid injection device 100 may also include a processor (not shown). The processor is used to control the corresponding operation of the power source 60 and each valve. The processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0046] As shown in FIG1 , the liquid injection device 100 may further include a hollow fixed frame 90, within which are disposed a first partition 91, a second partition 92, and a third partition 93 spaced apart from each other. The second partition 92 is disposed between the first partition 91 and the third partition 93. The first container 10 may be fixed to the first partition 91, and the second container 20 may be simultaneously fixed to at least one of the second partition 92 and the third partition 93. The power source 60 and the transmission liquid source 40 may be disposed in the space between the first partition 91 and the second partition 92. The reaction liquid source 50 may be disposed in the space on the side of the third partition 93 facing away from the second partition 92. The reaction device 200 is disposed outside the fixed frame 90, and the sixth pipeline 81 may pass through the fixed frame 90 and connect to the reaction device 200.

[0047] As shown in Figure 7, another embodiment of the present application also provides a liquid injection device 100a. The difference from the above-mentioned liquid injection device 100 is that if the first container 10, the second container 20 and the first connecting member 30 are collectively used as the primary injection mechanism L1, the liquid injection device 100a also includes at least one secondary injection mechanism L2 located in the downstream section of the primary injection mechanism L1. Figure 7 takes the liquid injection device 100a including a secondary injection mechanism L2 as an example to illustrate the specific structure of the secondary injection mechanism L2. Among them, in the second container 20 of the primary injection mechanism L1, the fourth cavity 212 is used to accommodate the transmission liquid instead of the reaction liquid. Moreover, the third inlet 23 and the outlet 22 can be integrated into the same connection port O, and the connection port O is not directly connected to the reaction device 200 and the reaction liquid source 50.

[0048] The secondary injection mechanism L2 is located in the third container 300, the fourth container 400, and the second connecting member 500 in the downstream section of the fourth cavity 212. In the first direction X, the third container 300 is arranged between the second container 20 and the fourth container 400. A third accommodating chamber 301 is defined in the third container 300, and a fourth accommodating chamber 401 is defined in the fourth container 400. The second connecting member 500 includes a third sliding portion 501, a fourth sliding portion 502, and a second connecting portion 503 connected between the third sliding portion 501 and the fourth sliding portion 502. The third sliding portion 501 is slidably disposed in the third accommodating chamber 301, and the fourth sliding portion 502 is slidably disposed in the fourth accommodating chamber 401. The third sliding portion 501 includes a fifth surface 5011 and a sixth surface 5012 disposed opposite to each other, and one end of the second connecting portion 503 is fixed to the sixth surface 5012. The fourth sliding portion 502 includes a seventh surface 5021 and an eighth surface 5022 disposed opposite each other, and the other end of the second connecting portion 503 is fixed to the seventh surface 5021. The structure of the second connecting member 500 can be similar to that of the first connecting member 30, and the configurations of the third accommodating cavity 301 and the fourth accommodating cavity 401 can be the same as those of the first accommodating cavity 11 and the second accommodating cavity 21, respectively.

[0049] The third sliding portion 501 divides the third accommodating chamber 301 into a fifth chamber 3011 and a sixth chamber 3012, which are isolated from each other. The fifth surface 5011 faces the fifth chamber 3011, and the sixth surface 5012 faces the sixth chamber 3012. The fifth chamber 3011 is further away from the fourth accommodating member 400 than the sixth chamber 3012. The fifth chamber 3011 is used to hold transmission fluid and is connected to the connection port O of the fourth chamber 212 via a conduit (e.g., a hose). The sixth chamber 3012 contains air.

[0050] The fourth sliding portion 502 divides the fourth accommodating chamber 401 into a seventh chamber 4011 and an eighth chamber 4012, which are isolated from each other. The seventh surface 5021 faces the seventh chamber 4011, and the eighth surface 5022 faces the eighth chamber 4012. The eighth chamber 4012 is farther away from the third accommodating member 300 than the seventh chamber 4011. The seventh chamber 4011 contains air, and the eighth chamber 4012 is used to hold a reaction liquid.

[0051] The fourth container 400 further defines an outlet 402 and a third inlet 403, both of which communicate with the eighth chamber 4012. The outlet 402 is configured to communicate with at least one reaction device 200, allowing the reaction liquid in the eighth chamber 4012 to be injected into the reaction device 200 via the outlet 402. The third inlet 403 is configured to communicate with the reaction liquid source 50, allowing the reaction liquid in the reaction liquid source 50 to be injected into the eighth chamber 4012 via the third inlet 403.

[0052] During operation, the first cavity 111, the second cavity 112, the fourth cavity 212, and the fifth cavity 3011 are each filled with transmission liquid. When the liquid injection device 100a is in injection mode M1, transmission liquid from the transmission liquid source 40 continues to be injected into the first cavity 111 through the first inlet 12. The pressure in the first cavity 111 increases, and the transmission liquid in the first cavity 111 acts on the first surface 311, driving the first sliding portion 31 to slide along the first direction X within the first accommodating cavity 11. This, in turn, drives the second sliding portion 32 to slide along the first direction X within the second accommodating cavity 21 via the first connecting portion 33, resulting in a smaller space in the fourth cavity 212 and an increased pressure. Consequently, the transmission liquid in the fourth cavity 212 is squeezed and injected into the fifth cavity 3011 through the connecting port O. Similarly, the pressure in the fifth cavity 3011 increases, so the transmission fluid in the fifth cavity 3011 can act on the fifth surface 5011 and drive the third sliding portion 501 to slide along the first direction X within the third accommodating cavity 301. This, in turn, drives the fourth sliding portion 502 to slide along the first direction X within the fourth accommodating cavity 401 via the second connecting portion 503. This reduces the space in the eighth cavity 4012 and increases the pressure. Consequently, the reaction liquid in the eighth cavity 4012 can be squeezed and injected into the reaction device 200.

[0053] When the liquid injection device 100a is in the liquid replenishment mode M2, transmission liquid from the transmission liquid source 40 is injected into the second chamber 112 via the second inlet 13. The pressure within the second chamber 112 increases. Consequently, the transmission liquid within the second chamber 112 acts on the second surface 312, driving the first sliding portion 31 to slide within the first accommodating chamber 11 in the direction opposite to the first direction X. This, in turn, drives the second sliding portion 32 to slide within the second accommodating chamber 21 in the direction opposite to the first direction X via the first connecting portion 33, thereby increasing the volume of the fourth chamber 212 and reducing the pressure. Consequently, the transmission liquid in the fifth chamber 3011 is injected into the fourth chamber 212 via the connecting port O under the pressure differential. Similarly, the pressure within the fifth chamber 3011 decreases, causing the fourth sliding portion 502, via the second connecting portion 503, to drive the third sliding portion 501 to slide within the third accommodating chamber 301 in the direction opposite to the first direction X, thereby increasing the volume of the eighth chamber 4012 and reducing the pressure. Therefore, the reaction liquid in the reaction liquid source 50 is injected into the eighth cavity 4012 through the third inlet 403 , thereby replenishing the reaction liquid in the eighth cavity 4012 .

[0054] Similar to the liquid injection device 100, when the liquid injection device 100a is in the injection mode M1, the transmission liquid drives the first sliding portion 31 to slide within the first accommodating chamber 11 along the first direction X. The transmission liquid acts on the first surface 311, resulting in a larger effective area. Therefore, the sliding speed of the first sliding portion 31 is relatively low. However, compared to the liquid injection device 100, in the liquid injection device 100a, the transmission liquid is further injected into the fifth cavity 3011 through the connection port O and then acts on the fifth surface 5011, resulting in a larger effective area (the area of ​​the fifth surface 5011 is larger than the area of ​​the fourth surface 322). Therefore, the sliding speed of the third sliding portion 501 can be further reduced compared to the sliding speed of the first sliding portion 31. Since the sliding speed of the third sliding portion 501 is equal to the sliding speed of the fourth sliding portion 502, this embodiment can further reduce the injection speed.

[0055] When the liquid injection device 100a includes multiple secondary injection mechanisms L2, the multiple secondary injection mechanisms L2 are sequentially connected in series in the first direction X. Among the multiple secondary injection mechanisms L2, there is one secondary injection mechanism L2 closest to the primary injection mechanism L1 in the first direction X, and there is also one secondary injection mechanism L2 farthest from the primary injection mechanism L1 in the first direction X. The multiple secondary injection mechanisms L2 can be substantially identical in structure, except that, in the secondary injection mechanism L2 farthest from the primary injection mechanism L1 in the first direction X, the eighth cavity 4012 is used to hold the reaction liquid and has an outlet 402 and a third inlet 403; in the remaining secondary injection mechanisms L2, the eighth cavity 4012 is used to hold the transmission liquid and is connected to the fifth cavity 3011 of the next secondary injection mechanism L2 via a pipe (such as a hose). Because the transmission liquid in the eighth cavity 4012 of the previous secondary injection mechanism L2 is further injected into the fifth cavity 3011 of the next secondary injection mechanism L2 and acts on the fifth surface 5011, the effective area is larger (the area of ​​the fifth surface 5011 is larger than the area of ​​the eighth surface 5022 of the previous secondary injection mechanism L2). Therefore, the sliding speed of the third sliding portion 501 of the next secondary injection mechanism L2 can be further reduced compared to the sliding speed of the third sliding portion 501 of the previous secondary injection mechanism L2. Therefore, providing multiple secondary injection mechanisms L2 can further reduce the injection speed.

[0056] Referring to FIG8 , one embodiment of the present application further provides a liquid injection method, which can be applied to the liquid injection device 100 or 100a described above. The order of the steps in the method described above can be changed according to different requirements, and some steps can be omitted or combined. The liquid injection method described above includes the following steps:

[0057] In step S1 , the liquid injection device 100 is switched to the liquid injection mode M1 .

[0058] In some embodiments, the first valve 65 is controlled to connect the first pipe 61 to the third pipe 63 and the second pipe 62 to the fourth pipe 64 , thereby switching the liquid injection device 100 or 100 a to the liquid injection mode M1 .

[0059] Before switching the liquid injection device 100 or 100a to the liquid injection mode M1, the first inlet 12 and the second inlet 13 can be connected to the transmission liquid source 40, respectively, to facilitate the subsequent injection of transmission liquid through the first inlet 12 and the second inlet 13. Furthermore, the third inlet 23 can be connected to the reaction liquid source 50 to facilitate the subsequent replenishment of reaction liquid through the third inlet 23.

[0060] In step S2, a transmission liquid is injected into the first cavity 111 through the first inlet 12, so that the transmission liquid acts on the first surface 311 and drives the second sliding portion 32 to slide through the first connecting portion 33, so that the space of the fourth cavity 212 is reduced and the reaction liquid in the fourth cavity 212 or the downstream section of the fourth cavity 212 is injected into the reaction device 200 through the outlet 22 (or outlet 402).

[0061] In some embodiments, the transmission liquid in the transmission liquid source 40 is injected into the first inlet 12, and the transmission liquid in the second cavity 112 is returned to the transmission liquid source 40 through the second inlet 13. Furthermore, the power source 60 can be turned on, thereby providing power for the transmission liquid in the transmission liquid source 40 to flow through the first conduit 61 and the third conduit 63, so that the transmission liquid is injected into the first cavity 111 through the first inlet 12.

[0062] As shown in FIG3 , in the liquid injection device 100, the fourth chamber 212 is directly connected to the reaction device 200 via the outlet 22. Therefore, in the injection mode M1, the reaction liquid in the fourth chamber 212 is directly injected into the reaction device 200 via the outlet 22. As shown in FIG7 , in the liquid injection device 100a, at least one secondary injection mechanism L2 is further provided in the downstream section of the fourth chamber 212. Each secondary injection mechanism L2 comprises a third container 300, a fourth container 400, and a second connector 500. When one secondary injection mechanism L2 is present, in the injection mode M1, the transmission liquid in the fourth chamber 212 is injected into the fifth chamber 3011. The transmission liquid in the fifth chamber 3011 acts on the fifth surface 5011 and drives the fourth sliding portion 502 to slide via the second connector 503, thereby injecting the reaction liquid in the eighth chamber 4012 into the reaction device 200. When there are multiple secondary injection mechanisms L2, the transmission liquid in the fourth cavity 212 is injected into the fifth cavity 3011 in the secondary injection mechanism L2 closest to the fourth cavity 212. The transmission liquid in the fifth cavity 3011 acts on the fifth surface 5011 and drives the fourth sliding part 502 to slide through the second connecting part 503, so that the transmission liquid in the eighth cavity 4012 is injected into the fifth cavity 3011 of the next secondary injection mechanism L2, until the reaction liquid in the eighth cavity 4012 in the secondary injection mechanism L2 farthest from the fourth cavity 212 is injected into the reaction device 200.

[0063] Step S3: Switch the liquid injection device 100 or 100a to the liquid replenishment mode M2.

[0064] In some embodiments, the first valve 65 is controlled to connect the first pipe 61 to the fourth pipe 64 and the second pipe 62 to the third pipe 63 , thereby switching the liquid injection device 100 or 100 a to the liquid infusion mode M2 ​​.

[0065] In step S4, a transmission liquid is injected into the second cavity 112 through the second inlet 13, so that the transmission liquid acts on the second surface 312 and drives the second sliding portion 32 to slide through the first connecting portion 33, thereby increasing the space of the fourth cavity 212 and injecting the reaction liquid into the fourth cavity 212 or the downstream section of the fourth cavity 212 through the third inlet 23 (or the third inlet 403).

[0066] In some embodiments, the power source 60 remains on, thereby providing power for the transmission fluid in the transmission fluid source 40 to flow through the first conduit 61 and the fourth conduit 64 , such that the transmission fluid is injected into the second cavity 112 through the second inlet 13 .

[0067] As shown in FIG4 , in the liquid injection device 100, the fourth chamber 212 is directly connected to the reaction liquid source 50 via the third inlet 23. Therefore, in the liquid replenishment mode M2, the reaction liquid in the reaction liquid source 50 is directly injected into the fourth chamber 212 via the third inlet 23. As shown in FIG7 , in the liquid injection device 100a, at least one secondary injection mechanism L2 is further provided downstream of the fourth chamber 212. Each secondary injection mechanism L2 includes a third accommodating member 300, a fourth accommodating member 400, and a second connecting member 500. When only one secondary injection mechanism L2 is present, in the liquid replenishment mode M2, the transmission liquid in the fifth chamber 3011 is injected into the fourth chamber 212, causing the fourth sliding portion 502 to slide the third sliding portion 501 via the second connecting portion 503, causing the reaction liquid in the reaction liquid source 50 to be injected into the eighth chamber 4012 via the third inlet 403. When there are multiple secondary injection mechanisms L2, the transmission liquid in the fifth cavity 3011 of the secondary injection mechanism L2 closest to the fourth cavity 212 is injected into the fourth cavity 212. The specific movement mode of each component in each secondary injection mechanism L2 is opposite to the movement mode of the component under the injection mode M1, which will not be repeated here.

[0068] In this application, the liquid injection device 100 or 100a can be repeatedly switched between the liquid injection mode M1 and the liquid replenishment mode M2, thereby increasing the injection volume.

[0069] Referring to FIG. 9 , one embodiment of the present application further provides a microfluidic system 1 comprising a reaction device 200 and at least one liquid injection device 100 or 100a. The reaction device 200 is specifically a microfluidic chip. Each liquid injection device 100 or 100a is used to inject a liquid (e.g., a reagent) into the microfluidic chip to promote or facilitate biochemical reactions within the microfluidic chip.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A liquid injection device for connecting to at least one reaction device, characterized in that, The liquid injection device includes: a first accommodating member having a first accommodating cavity; a second accommodating member having a second accommodating cavity; and a first connecting member including a first sliding portion, a second sliding portion, and a first connecting portion connecting between the first sliding portion and the second sliding portion. The first sliding portion includes a first surface and a second surface disposed opposite to each other. The first connecting portion is connected to the second surface. The first sliding portion is slidably disposed in the first accommodating cavity and divides the first accommodating cavity into a first cavity and a second cavity that are isolated from each other. The first surface faces the first cavity, and the second surface faces the second cavity. Both the first cavity and the second cavity are used to accommodate transmission liquid. The second sliding portion is slidably disposed in the second accommodating cavity and divides the second accommodating cavity into a third cavity and a fourth cavity that are isolated from each other. The fourth cavity or a downstream section of the fourth cavity is used to accommodate reaction liquid supplied to the reaction device; The liquid injection device has a liquid injection mode and a liquid replenishment mode. In the liquid injection mode, the transmission liquid injected into the first cavity acts on the first surface and drives the second sliding portion to slide through the first connecting portion, so that the reaction liquid in the fourth cavity or the downstream section of the fourth cavity is injected into the reaction device. In the liquid replenishment mode, the transmission liquid injected into the second cavity acts on the second surface and drives the second sliding portion to slide through the first connecting portion, so that the fourth cavity or the downstream section of the fourth cavity accommodates the reaction liquid injected therein. The area of the transmission liquid acting on the first surface is larger than the area of the transmission liquid acting on the second surface.

2. The liquid injection device according to claim 1, wherein The liquid injection device further includes a transmission liquid source for storing the transmission liquid. The first cavity and the second cavity are respectively connected to the transmission liquid source, so that the transmission liquid in the transmission liquid source can be injected into the first cavity and the second cavity.

3. The liquid injection device according to claim 2, wherein The transmission liquid source includes an independent first storage module and a second storage module. The liquid injection device further includes a power source and a first valve. The power source is connected to the first storage module. The first valve is used to connect the first storage module to the first cavity and connect the second storage module to the second cavity, thereby switching the liquid injection device to the liquid injection mode. The first valve is further used to connect the first storage module to the second cavity and connect the second storage module to the first cavity, thereby switching the liquid injection device to the liquid replenishment mode. The power source is used to provide power for the transmission liquid in the transmission liquid source to flow into the first cavity or the second cavity.

4. The liquid injection device according to claim 3, wherein The liquid pumping speed of the power source in the liquid injection mode is less than the liquid pumping speed of the power source in the liquid replenishment mode.

5. The liquid injection device according to claim 3, characterized in that, The liquid pumping speed of the power source in the liquid injection mode is equal to the liquid pumping speed of the power source in the liquid replenishment mode.

6. The liquid injection device according to claim 1, wherein, The fourth cavity is connected to the reaction device. The liquid injection device further includes a reaction liquid source for storing the reaction liquid. The fourth cavity is also connected to the reaction liquid source, so that the reaction liquid in the reaction liquid source can be injected into the fourth cavity.

7. The liquid injection device according to claim 6, wherein The liquid injection device further includes a second valve and a third valve. The second valve is connected between the fourth cavity and the reaction device, and the third valve is connected between the fourth cavity and the reaction liquid source. In the liquid injection mode, the second valve conducts the fourth cavity and the reaction device, and the third valve blocks the reaction liquid source from the fourth cavity. In the liquid replenishment mode, the third valve conducts the fourth cavity and the reaction liquid source, and the second valve blocks the fourth cavity from the reaction device.

8. The liquid injection device according to claim 7, wherein, The number of the second valves is multiple, and each second valve is used to connect a reaction device to the fourth cavity.

9. The liquid injection device according to claim 1, wherein, The number of the second receiving members and the second sliding portions is multiple. Each second sliding portion is slidably disposed in the second receiving cavity of a second receiving member. The fourth cavity of each second receiving cavity is connected to a reaction device. The first connecting portion includes a first connecting sub-portion and a plurality of second connecting sub-portions connected to the first connecting sub-portion. The first connecting sub-portion is connected to the first sliding portion, and each second connecting sub-portion is respectively connected to a second sliding portion.

10. The liquid injection device according to claim 1, wherein The second sliding portion includes a third surface facing the third cavity and a fourth surface facing the fourth cavity. The area of the fourth surface is smaller than the area of the first surface.

11. The liquid injection device according to claim 10, wherein, The liquid injection device further includes: a third receiving member having a third receiving cavity; a fourth receiving member having a fourth receiving cavity; and a second connecting member including a third sliding portion, a fourth sliding portion, and a second connecting portion connected between the third sliding portion and the fourth sliding portion. The third sliding portion includes a fifth surface and a sixth surface disposed opposite to each other. The second connecting portion is connected to the sixth surface. The third sliding portion is slidably disposed in the third receiving cavity and divides the third receiving cavity into a mutually isolated fifth cavity and a sixth cavity. The fifth surface faces the fifth cavity, and the area of the fifth surface is larger than the area of the fourth surface. The sixth surface faces the sixth cavity. The fifth cavity is located in the downstream section of the fourth cavity. The fifth cavity and the fourth cavity are in communication with each other and are both used to accommodate the transmission liquid. The fourth sliding portion is slidably disposed in the fourth receiving cavity and divides the fourth receiving cavity into a mutually isolated seventh cavity and an eighth cavity. The eighth cavity is connected to the reaction device and is used to accommodate the reaction liquid supplied to the reaction device.

12. The liquid injection device according to claim 11, wherein The sixth cavity is used to accommodate air.

13. The liquid injection device according to claim 10, characterized in that, The fourth cavity is used to accommodate the transmission liquid. The liquid injection device further includes a plurality of secondary injection mechanisms located in the downstream section of the fourth cavity and connected in series in sequence. Each secondary injection structure includes: a third receiving member having a third receiving cavity; A fourth accommodating member, which is provided with a fourth accommodating cavity; and A second connecting member, including a third sliding portion, a fourth sliding portion, and a second connecting portion connecting between the third sliding portion and the fourth sliding portion. The third sliding portion includes a fifth surface and a sixth surface arranged oppositely, the second connecting portion is connected to the sixth surface, the third sliding portion is slidably arranged in the third accommodating cavity and divides the third accommodating cavity into a mutually isolated fifth cavity and a sixth cavity. The fifth surface faces the fifth cavity, the area of the fifth surface is larger than the area of the fourth surface, the sixth surface faces the sixth cavity, the fourth sliding portion is slidably arranged in the fourth accommodating cavity and divides the fourth accommodating cavity into a mutually isolated seventh cavity and an eighth cavity; The fifth cavity of each of the secondary injection mechanisms is used to accommodate the transmission liquid; in the secondary injection mechanism closest to the fourth cavity, the fifth cavity communicates with the fourth cavity, and the eighth cavity is used to accommodate the transmission liquid; in two adjacent secondary injection mechanisms, the eighth cavity of the previous secondary injection mechanism communicates with the fifth cavity of the next secondary injection mechanism; in the secondary injection mechanism farthest from the fourth cavity, the eighth cavity is connected to the reaction device and is used to accommodate the reaction liquid supplied to the reaction device.

14. The liquid injection device according to claim 13, wherein, In two adjacent secondary injection mechanisms, the eighth cavity of the previous secondary injection mechanism communicates with the fifth cavity of the next secondary injection mechanism through a pipeline.

15. The liquid injection device according to claim 13, wherein, The fourth sliding portion includes a seventh surface and an eighth surface arranged oppositely, the second connecting portion is connected to the seventh surface, and in two adjacent secondary injection mechanisms, the area of the eighth surface of the previous secondary injection mechanism is smaller than the area of the fifth surface of the next secondary injection mechanism.

16. The liquid injection device according to claim 1, wherein, The diameter of one end of the first connecting portion close to the first sliding portion is larger than the diameter of the other end of the first connecting portion close to the second sliding portion.

17. The liquid injection device according to claim 1, wherein, The first connecting portion is made of a rigid material.

18. A liquid injection method applied to the liquid injection device as described in claim 1, characterized in that, Including the following steps: Switch the liquid injection device to the liquid injection mode; Inject the transmission liquid into the first cavity, so that the transmission liquid acts on the first surface and drives the second sliding portion to slide through the first connecting portion, so that the reaction liquid in the fourth cavity or the downstream section of the fourth cavity is injected into the reaction device; Switch the liquid injection device to the liquid replenishment mode; And Inject the transmission liquid into the second cavity, so that the transmission liquid acts on the second surface and drives the second sliding portion to slide through the first connecting portion, so that the fourth cavity or the downstream section of the fourth cavity accommodates the reaction liquid injected therein.

19. The liquid injection method according to claim 18, characterized in that, The liquid injection method repeatedly switches the liquid injection device between the liquid injection mode and the liquid replenishment mode.

20. The liquid injection method according to claim 19, characterized in that, The liquid injection device further includes a transmission liquid source. Before the liquid injection device is first switched to the liquid injection mode, the liquid injection method further includes: Connect the first cavity and the second cavity to the transmission liquid source respectively, so that the transmission liquid in the transmission liquid source is injected into the first cavity in the liquid injection mode, and the transmission liquid in the transmission liquid source is injected into the second cavity in the liquid replenishment mode.

21. The liquid injection method according to claim 20, wherein, The transmission liquid source includes an independent first storage module and a second storage module. The liquid injection device further includes a power source and a first valve. The power source is connected to the first storage module. Specifically, switching the liquid injection device to the liquid injection mode includes: The first valve connects the first storage module to the first cavity and connects the second storage module to the second cavity, and turns on the power source to provide power for the transmission liquid in the transmission liquid source to flow to the first cavity; Specifically, switching the liquid injection device to the liquid replenishment mode includes: The first valve connects the first storage module to the second cavity and connects the second storage module to the first cavity, so that the power source provides power for the transmission liquid in the transmission liquid source to flow to the second cavity.

22. The liquid injection method according to claim 21, wherein The liquid pumping speed of the power source in the liquid injection mode is less than the liquid pumping speed of the power source in the liquid replenishment mode.

23. The liquid injection method according to claim 21, wherein The liquid pumping speed of the power source in the liquid injection mode is equal to the liquid pumping speed of the power source in the liquid replenishment mode.

24. The liquid injection method according to claim 18, characterized in that, The fourth cavity is connected to the reaction device. The liquid injection device further includes a reaction liquid source. Before the liquid injection device is first switched to the liquid injection mode, the liquid injection method further includes: Connect the fourth cavity to the reaction liquid source, so that the reaction liquid in the reaction liquid source is injected into the fourth cavity in the liquid replenishment mode.

25. The liquid injection method according to claim 18, wherein The liquid injection device further includes a third accommodating member, a fourth accommodating member and a second connecting member. The third accommodating member is provided with a third accommodating cavity, the fourth accommodating member is provided with a fourth accommodating cavity. The second connecting member includes a third sliding portion, a fourth sliding portion, and a second connecting portion connected between the third sliding portion and the fourth sliding portion. The third sliding portion includes a fifth surface and a sixth surface arranged opposite to each other. The second connecting portion is connected to the sixth surface. The third sliding portion is slidably arranged in the third accommodating cavity and divides the third accommodating cavity into a fifth cavity and a sixth cavity that are isolated from each other. The fifth surface faces the fifth cavity, and the sixth surface faces the sixth cavity. The fifth cavity is located in the downstream section of the fourth cavity. The fifth cavity is communicated with the fourth cavity and is both used to accommodate the transmission liquid. The fourth sliding portion is slidably arranged in the fourth accommodating cavity and divides the fourth accommodating cavity into a seventh cavity and an eighth cavity that are isolated from each other. The eighth cavity is connected to the reaction device and is used to accommodate the reaction liquid supplied to the reaction device; After injecting the transmission liquid into the first cavity, the transmission liquid in the fourth cavity is injected into the fifth cavity. The transmission liquid in the fifth cavity acts on the fifth surface and drives the fourth sliding part to slide through the second connecting part, so that the reaction liquid in the eighth cavity is injected into the reaction device. After injecting the transmission liquid into the second cavity, the transmission liquid in the fifth cavity is injected into the fourth cavity, so that the fourth sliding part drives the third sliding part to slide through the second connecting part, and the eighth cavity accommodates the reaction liquid injected therein.

26. The liquid injection method according to claim 25, characterized in that, The sixth cavity is used to accommodate air.

27. The liquid injection method according to claim 18, wherein The liquid injection device further includes a plurality of secondary injection mechanisms located in the downstream section of the fourth cavity and connected in series in sequence. Each secondary injection structure includes a third accommodating member, a fourth accommodating member, and a second connecting member. The third accommodating member is provided with a third accommodating cavity, the fourth accommodating member is provided with a fourth accommodating cavity, the second connecting member includes a third sliding part, a fourth sliding part, and a second connecting part connected between the third sliding part and the fourth sliding part. The third sliding part includes a fifth surface and a sixth surface arranged oppositely, the second connecting part is connected to the sixth surface, the third sliding part is slidably arranged in the third accommodating cavity and divides the third accommodating cavity into a fifth cavity and a sixth cavity that are isolated from each other. The fifth surface faces the fifth cavity, the sixth surface faces the sixth cavity, and the fourth sliding part is slidably arranged in the fourth accommodating cavity and divides the fourth accommodating cavity into a seventh cavity and an eighth cavity that are isolated from each other; the fifth cavity of each secondary injection mechanism is used to accommodate the transmission liquid; in the secondary injection mechanism closest to the fourth cavity, the fifth cavity communicates with the fourth cavity, and the eighth cavity is used to accommodate the transmission liquid; In two adjacent secondary injection mechanisms, the eighth cavity of the previous secondary injection mechanism communicates with the fifth cavity of the next secondary injection mechanism; in the secondary injection mechanism farthest from the fourth cavity, the eighth cavity is connected to the reaction device and is used to accommodate the reaction liquid supplied to the reaction device; After injecting the transmission liquid into the first cavity, the transmission liquid in the fourth cavity is injected into the fifth cavity of the secondary injection mechanism closest to the fourth cavity. The transmission liquid in the fifth cavity acts on the fifth surface and drives the fourth sliding part to slide through the second connecting part, so that the transmission liquid in the eighth cavity is injected into the fifth cavity of the next secondary injection mechanism until the reaction liquid in the eighth cavity is injected into the reaction device.

28. The liquid injection method according to claim 27, wherein The fourth sliding part includes a seventh surface and an eighth surface arranged oppositely, the second connecting part is connected to the seventh surface, and in two adjacent secondary injection mechanisms, the area of the eighth surface of the previous secondary injection mechanism is smaller than the area of the fifth surface of the next secondary injection mechanism.

29. A microfluidic system, comprising a reaction device, wherein the reaction device is a microfluidic chip, characterized in that, The microfluidic system further includes the liquid injection device as described in any one of claims 1 to 17, and the fourth cavity of the liquid injection device is in communication with the microfluidic chip.

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