Microfluidic devices and methods of using the same

Abstract

The present disclosure belongs to the technical field of microfluidics, and discloses a microfluidic device and a method for using the same. The microfluidic device comprises a rotating mechanism, a rotating assembly and a microfluidic assembly. The rotating assembly is rotationally connected to the microfluidic assembly through the rotating mechanism. The rotating assembly comprises a first limiting mechanism, a rotating assembly body and a sealing layer. The first limiting mechanism is detachably fixedly connected to the rotating assembly body. The microfluidic assembly comprises a cover plate and a flow channel plate. The cover plate is connected to the flow channel plate. The cover plate is provided with a flow channel port, a second limiting mechanism and a liquid passing hole. The flow channel plate is provided with a plurality of flow channel segments. Each flow channel port is in communication with one end of a flow channel segment, serving as a liquid injection hole or a liquid outlet hole. The first limiting mechanism and the second limiting mechanism cooperate to limit the relative position of the rotating assembly and the microfluidic assembly. The microfluidic device of the present disclosure can control, sense and temporarily store microfluids, and the operation process is simple and convenient.

Description

Technical Field

[0001] This disclosure belongs to the field of microfluidics technology, and more specifically, this disclosure provides a microfluidic device and a method for using it. Background Technology

[0002] Microfluidics is the science and technology involved in systems that use microchannels to process or manipulate tiny fluids. It is an emerging interdisciplinary field involving chemistry, physics, microelectronics, new materials, biology, and biomedical engineering. Due to its miniaturization and integration characteristics, microfluidics is widely used in fields such as chemistry, medicine, and life sciences.

[0003] Microfluidic valves can be categorized into: rotary valves, paraffin valves, paraffin melt valves, magnetic actuation valves, pneumatic valves, and mechanical valves. Rotary valves close when a rotor's micropillar contacts a micro-hole in the base. Paraffin valves are typically used within chips where liquids are centrifugally driven; the centrifugal force forces the paraffin open. Paraffin melt valves use heat sources like lasers to directionally heat the valve area, melting it and opening the valve. Magnetic actuation valves open and close using the movement of a magnet in a magnetic environment. Pneumatic valves use gas to inflate and fill a portion containing an elastic component, achieving a valve-like effect. Mechanical valves work by the device and chip working together; the device extends and retracts to compress a portion of the chip, achieving a valve-like effect.

[0004] The aforementioned microfluidic valves only control a single flow channel. When it is necessary to control dual or multiple flow channels, multiple valves need to be installed for separate control, which will result in a complex structure and high cost for the microfluidic device. Summary of the Invention

[0005] One of the objectives of this disclosure is to design an improved microfluidic device for controlling dual-channel or multi-channel flow.

[0006] Therefore, in a first aspect, this disclosure provides a microfluidic device, which includes a rotating mechanism, a rotating assembly, and a microfluidic assembly, wherein the rotating assembly and the microfluidic assembly are rotatably connected via the rotating mechanism.

[0007] The rotating assembly includes a first limiting mechanism, a rotating assembly body, and a sealing layer. The first limiting mechanism is detachably and fixedly connected to the rotating assembly body. The sealing layer is fitted to the rotating assembly body. The lower surface of the sealing layer is provided with microchannel grooves for fluid passage.

[0008] The microfluidic assembly includes a cover plate and a flow channel plate, with the cover plate connected to the flow channel plate. The cover plate is provided with a flow channel opening, a second limiting mechanism, and a liquid passage hole. The flow channel plate is provided with multiple flow channel segments. Each flow channel opening is connected to one end of a flow channel segment, serving as an injection hole or an outlet hole. Each liquid passage hole is connected to one end of a flow channel segment. A group of liquid passage holes consisting of two or more liquid passage holes can cooperate with the microfluidic grooves on the sealing layer, so that the corresponding flow channel segments are connected.

[0009] The first limiting mechanism and the second limiting mechanism cooperate to limit the relative position of the rotating component and the microfluidic component;

[0010] The rotating component rotates relative to the microfluidic component to a first position, and one or more sets of liquid passage holes are connected through microchannel grooves to connect the corresponding flow channel segments, forming a through first flow channel. The two ends of the first flow channel have flow channel openings, which serve as injection holes and liquid outlet holes, respectively. The rotating component rotates relative to the microfluidic component to a second position, and one or more sets of liquid passage holes are connected through microchannel grooves to connect the corresponding flow channel segments, forming a through second flow channel. The two ends of the second flow channel have flow channel openings, which serve as injection holes and liquid outlet holes, respectively.

[0011] Preferably, the rotating component rotates to a third position relative to the microfluidic component, with no flow channel segments connected, thus no through flow channel is formed.

[0012] Preferably, the through flow channel includes three flow channel sections. The two ends of the middle flow channel section are connected to liquid passage holes, and the two ends of the two side flow channel sections are respectively connected to flow channel openings and liquid passage holes. The liquid passage holes connected to the middle flow channel section and the liquid passage holes connected to the two side flow channel sections form a liquid passage hole group.

[0013] Preferably, the first limiting mechanism is a limiting pin, and the second limiting mechanism is a limiting groove or a limiting hole. The limiting pin can move in the limiting groove to limit the relative position of the rotating component and the microfluidic component; or it can be fixed in the limiting hole to lock the relative position of the rotating component and the microfluidic component.

[0014] Preferably, different flow channel sections and / or different parts of the same flow channel section are located at different depths of the flow channel plate.

[0015] Preferably, the microfluidic component includes a sealing gasket and a sensing device located under the flow channel plate, and preferably the sealing gasket and the sensing device are detachable from the flow channel plate.

[0016] Preferably, the rotating mechanism is a fixed shaft.

[0017] Preferably, the cover plate is provided with two sets of flow channels and four pairs of liquid passage holes, and is provided with limiting grooves and limiting holes; the limiting pin moves in the limiting groove to control the first set of flow channels to communicate through the flow channels, the first pair of liquid passage holes and the second pair of liquid passage holes on the flow channel plate; the limiting pin corresponds to the limiting hole so that the second set of flow channels to communicate through the flow channels, the third pair of liquid passage holes and the fourth pair of liquid passage holes on the flow channel plate.

[0018] Preferably, when the limiting pin is at one end of the limiting groove, the first pair of liquid passage holes and the second pair of liquid passage holes are connected; when the limiting pin is at the other end of the limiting groove, the first pair of liquid passage holes and the second pair of liquid passage holes are not connected.

[0019] Preferably, the sealing layer is bonded to the rotating component body by means of hot melting, ultrasonic welding, laser welding, adhesive bonding, etc.

[0020] Preferably, the cover plate is a transparent cover plate.

[0021] Preferably, the cover plate is attached to the flow channel plate by bonding, ultrasonic welding, laser welding, adhesive bonding, or other methods.

[0022] In a second aspect, this disclosure provides a method of using the microfluidic device of the first aspect, the method comprising:

[0023] 1) Remove the fixing between the first limiting mechanism and the second limiting mechanism;

[0024] 2) Perform one or more of the following:

[0025] i) The rotating component rotates around the rotating mechanism relative to the microfluidic component to a first position, and one or more sets of liquid passage holes are connected through the microchannel groove to connect the corresponding flow channel segments to form a through first flow channel. The two ends of the first flow channel have flow channel openings, which serve as liquid injection holes and liquid outlet holes, respectively.

[0026] ii) The rotating component rotates about the rotating mechanism relative to the microfluidic component to a second position, and one or more sets of liquid passage holes are connected through the microchannel groove to connect the corresponding flow channel segments to form a through second flow channel. The two ends of the second flow channel have flow channel openings, which serve as liquid injection holes and liquid outlet holes, respectively.

[0027] 3) The first limiting mechanism and the second limiting mechanism cooperate to limit the relative positions of the rotating component and the microfluidic component.

[0028] Preferably, 2) further includes: iii) the rotating component rotates about the rotating mechanism relative to the microfluidic component to a third position, with no flow channel segment connected, and therefore no through flow channel is formed.

[0029] Preferably, the cover plate is provided with two sets of flow channels and four pairs of liquid passage holes, as well as limiting grooves and limiting holes;

[0030] In i), the limiting pin moves in the limiting groove to control the first set of flow channel openings to form a passage with the first flow channel on the flow channel plate. The first pair of liquid passage holes and the second pair of liquid passage holes on the first flow channel are connected or closed through the corresponding micro-flow channel grooves on the lower surface of the sealing layer, thereby controlling the first flow channel to be connected or closed.

[0031] In ii), the limiting pin corresponds to the limiting hole so that the second set of flow channel openings and the second flow channel on the flow channel plate form a passage. The third pair of liquid passage holes and the fourth pair of liquid passage holes on the second flow channel are connected through the corresponding microchannel grooves on the lower surface of the sealing layer, thereby controlling the connection of the second flow channel.

[0032] This disclosure enables the control, sensing, and temporary storage of trace fluids, and the operation process is simple and convenient. Attached Figure Description

[0033] The technical and industrial significance of the disclosed features, advantages, and exemplary embodiments will now be described with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same elements, and wherein:

[0034] Figure 1 A schematic diagram of a microfluidic device containing a three-position valve according to one embodiment of the present disclosure is shown.

[0035] Figure 2 A schematic diagram of a rotating assembly according to one embodiment of the present disclosure is shown, where A shows the lower surface of the rotating assembly; and B shows an exploded view of the rotating assembly.

[0036] Figure 3 A schematic diagram of a microfluidic assembly according to one embodiment of the present disclosure is shown, with A showing an exploded view; B showing a top view of the cover plate; and C showing a top view of the flow channel plate.

[0037] Figure 4 The diagram shows a microchannel groove with the liquid passages closed (the liquid passages are separated) (A), and a microchannel groove with the liquid passages open (the liquid passages are connected) (B).

[0038] Figure 5 The diagram illustrates two states of a microfluidic assembly with a three-position valve according to one embodiment of the present disclosure, with A showing the user mode in the open state and B showing the user mode in the closed state.

[0039] Figure 6A schematic diagram of the administrator mode of a microfluidic assembly with a three-position valve according to one embodiment of the present disclosure is shown. A shows a top perspective view of the administrator mode; B shows a flow diagram of the internal portion of the flow channel plate in the administrator mode; C shows an exploded view of the administrator mode. Detailed Implementation

[0040] To make the above and other features and advantages of this disclosure clearer, the disclosure is further described below in conjunction with the accompanying drawings. The drawings form part of this application and, together with embodiments of the disclosure, serve to illustrate the disclosure. For clarity and simplicity, detailed descriptions of the known functions and structures of the devices described herein will be omitted where they might obscure the subject matter of the disclosure. It should be understood that the specific embodiments given herein are for the purpose of explanation to those skilled in the art and are exemplary only, not restrictive.

[0041] In the following description, numerous specific details are set forth to provide a thorough understanding of this disclosure. However, it will be apparent to those skilled in the art that these specific details are not required to practice this disclosure. In other instances, well-known steps or operations have not been described in detail to avoid obscuring this disclosure.

[0042] Figure 1 The configuration of a microfluidic device with a three-position valve according to one embodiment of the present disclosure is shown, such as... Figure 1 As shown, the microfluidic device with a three-position valve disclosed herein may include a rotating mechanism 1, a rotating assembly 2, and a microfluidic assembly 3. In this disclosure, the rotating mechanism 1 can be a rotating shaft, but this disclosure does not exclude the possibility that the rotating mechanism 1 can be in other forms, such as through gears. The rotating assembly 2 is rotatably connected to the microfluidic assembly 3 via the rotating mechanism 1, and the rotating assembly 2 can rotate relative to the microfluidic assembly 3 via the rotating mechanism 1. In this disclosure, a microchannel groove is provided at the bottom of the rotating assembly 2, and a liquid passage is provided at the top of the microfluidic assembly 3. By rotating the rotating assembly 2 relative to the microfluidic assembly 3, the microchannel groove selectively connects to the liquid passage, thereby connecting the flow channel sections in the microfluidic assembly 3 to form a continuous flow channel.

[0043] In this disclosure, the rotating component 2 rotates relative to the microfluidic component 3 to multiple preset positions. At each preset position, multiple through-flow channels or non-through-flow channels can be formed. At each preset position, a limiting mechanism can limit the relative position of the rotating component 2 and the microfluidic component 3. The through-flow channels typically include three flow channel segments. The two ends of the middle flow channel segment are connected to through-holes, and the two ends of the side flow channel segments are respectively connected to flow outlets and through-holes. The through-holes connected to the middle flow channel segment, together with the through-holes connected to the side flow channel segments, form through-hole groups. The side flow channel segments are generally shorter than the middle flow channel segment, while the middle flow channel segment is usually longer and can be made into different shapes and have different volumes for various purposes. For example, different parts of the middle flow channel segment can be located at different depths of the flow channel plate, and some parts may have larger apertures, for example, to form a larger sealed chamber to seal more pre-stored liquid. In this disclosure, the continuous flow channel is not limited to three flow channel segments; it can have 4, 5, 6, 7, 8, 10, or even more flow channel segments, simply by increasing the number of intermediate flow channel segments. Those skilled in the art will understand that to form a continuous flow channel, multiple flow channel segments need to be connected end-to-end. In this disclosure, multiple flow channel segments can be connected in series through liquid passage holes at the ends of the flow channel segments. This requires the rotating component 2 to rotate relative to the microfluidic component 3 to a preset position, where corresponding microchannel grooves connect the corresponding liquid passage hole groups.

[0044] In this disclosure, two flow channel segments can be connected by liquid passage holes at their ends. Generally, one liquid passage hole on each flow channel segment is sufficient to connect the two flow channel segments. However, this disclosure does not exclude the possibility of connecting two flow channel segments by three or more liquid passage holes, for example, a flow channel segment with two or more liquid passage holes at its end. Furthermore, although this disclosure illustrates a single flow channel, one injection hole, and one outlet hole, it does not exclude the possibility of a branched flow channel, or a flow channel with two or more injection holes and outlet holes. For example, a continuous flow channel may branch in the middle and then rejoin, or it may not rejoin but be connected to outlet holes separately. As another example, flow channel segments connected by multiple injection holes may rejoin to connect to a single outlet hole. Those skilled in the art should understand that such embodiments are within the scope of this disclosure.

[0045] The composition and connection method of the rotating component 2 and the microfluidic component 3 of this device are described below.

[0046] Figure 2A schematic diagram of a rotating assembly according to one embodiment of this disclosure is shown. A shows the lower surface of the rotating assembly 2; B shows an exploded view of the rotating assembly 2. As shown, the rotating assembly 2 includes a first limiting mechanism 22, such as a limiting pin, a rotating assembly body 23, and a sealing layer 24. The rotating assembly 2 may also include a label 21 affixed to the upper surface of the first limiting mechanism 22. The label may be printed with text or images for warning or prompting the user (e.g., "Tear off and it's invalid"). The content printed on the label 21 is changeable. The first limiting mechanism 22 is fixed to the rotating assembly body 23, for example, by bolts, and can be removed by tools when needed. The sealing layer 24 can be bonded to the rotating assembly body 23 by means of heat fusion, ultrasonic welding, laser welding, adhesive bonding, etc. The sealing layer 24 can be peeled off from the rotating assembly body 23, and the sealing layer 24 can be replaced and re-bonded to the rotating assembly body 23 when needed. The sealing layer 24 is provided with microchannel grooves 71-74 for fluid passage. The microchannel groove is a short strip-shaped groove whose size and orientation are adapted to the liquid passage pair described later, and is used to adjust the connection of the liquid passage pair.

[0047] Figure 3 A schematic diagram of a microfluidic assembly according to one embodiment of the present disclosure is shown. A shows an exploded view of the microfluidic assembly. As shown in A, the microfluidic assembly 3 includes a cover plate 31, such as a transparent cover plate, a flow channel plate 32, a sealing gasket 33, and a sensing device 34. Typically, the cover plate 31 and the flow channel plate 32 are fixedly joined together, and the joining method can be bonding, ultrasonic welding, laser welding, adhesive bonding, etc. The sealing gasket 33 and the sensing device 34 are typically removable. B shows a top view of the cover plate 31, showing the various holes and slots. C shows a top view of the flow channel plate 32, which has multiple flow channel segments, which may be discontinuous. As shown in B, the cover plate 31 has flow channel openings 41-44, in pairs. Flow channel openings 41-44 are respectively connected to one end of a flow channel segment and can serve as injection or outlet holes for the flow channel. The transparent cover plate 31 also has pairs of liquid passage holes 61-64. The liquid passage holes 61-64 are located at the ends of the two flow channel sections, respectively, connecting the two flow channel sections. Each pair of liquid passage holes 61-64 corresponds to a microchannel groove 71-74 of the sealing layer 24 of the rotating assembly mentioned above. By adjusting the relative position of the liquid passage holes 61-64 and the microchannel groove 71-74, the connection or disconnection of the liquid passage holes 61-64 can be adjusted, thereby controlling the connection or disconnection of the flow channel sections. For example, adjusting the direction of the microchannel groove to be consistent with the direction of the liquid passage hole pair makes the liquid passage hole pair connected; adjusting the liquid passage hole to not be on the microchannel groove makes the liquid passage hole pair disconnected. Figure 4Figures A and B illustrate the states where the microchannel groove closes the liquid passage pair (the liquid passages are separated) and the states where the microchannel groove opens the liquid passage pair (the liquid passages are connected), respectively. As exemplarily shown in Figure A, the sealing layer 24 disconnects the liquid passage pair 61; as exemplarily shown in Figure B, the microchannel groove 72 connects the liquid passage pair 61.

[0048] In one specific implementation, to facilitate the differentiation of the application scenarios of the microfluidic component, the application scenarios of the microfluidic component can be divided into user mode and administrator mode. In administrator mode, the microfluidic component is pre-packaged with the reaction solution at the factory. Users cannot use administrator mode; after use, the component is returned to the factory, and the reaction solution can be added again. Flow channels 41 and 44 are the injection or outlet ports used in user mode. Flow channels 41 and 44 are located at opposite ends of a through-channel; when one is an injection port, the other is an outlet port, and the two can be used interchangeably. Flow channels 42 and 43 are the injection or outlet ports used in administrator mode. Flow channels 42 and 43 are located at opposite ends of a through-channel; when one is an injection port, the other is an outlet port, and the two can be used interchangeably. The cover plate includes a second limiting mechanism, which, together with the first limiting mechanism, limits the relative position of the rotating component and the microfluidic component. Here, the first limiting mechanism is the limiting pin 22, and the second limiting mechanism includes a limiting groove 50 and a limiting hole 51. The limiting groove 50 is used to limit the range of motion of the limiting pin 22, and is used in user mode in this example. The limiting hole 51 is used to limit the position of the limiting pin 22, and is used in administrator mode in this example. In different modes, i.e., when the rotating component 2 is at different angles, the four pairs of liquid passage holes 61-64 can achieve connection and isolation.

[0049] The following is passed Figure 5 and 6 An exemplary description illustrates a specific implementation of a microfluidic device with a three-position valve according to one embodiment of this disclosure. For clarity, only the rotating assembly, cover plate, and flow channel plate are shown in the figures. Figure 5 As shown, a microfluidic assembly with a three-position valve according to one embodiment of the present disclosure includes two user mode states: A shows the user mode open state; B shows the user mode closed state.

[0050] When the rotating component 2 is in Figure 5 In position A (this position is user mode 1, where both pairs of liquid passages are open, allowing for liquid injection or drainage), the two pairs of liquid passages 62 and 64 are connected through microchannel grooves 74 and 73, respectively, forming a flow channel in the direction indicated by the arrow. Liquid injection or drainage can be performed through flow channel openings 41 or 44. Figure 5The arrow A indicates the fluid direction when 44 is the injection port and 41 is the drain port. When 41 is the injection port and 44 is the drain port, the fluid movement direction is opposite to the arrow direction. In this case, the flow channels 42 and 43 are blocked by the rotating assembly body 23 to prevent user misoperation.

[0051] When the rotating component 2 is in Figure 5 In position B (this is user mode 2, where all liquid passage pairs are closed and liquid injection or drainage operations cannot be performed), at this time, none of the liquid passage pairs are connected by the microchannels at the sealing layer. Furthermore, each flow channel opening is blocked by the rotating component body 23, preventing the user from performing liquid injection or drainage operations.

[0052] like Figure 6 As shown, the administrator mode state of a microfluidic assembly with a three-position valve according to one embodiment of this disclosure is represented by AC. Wherein, A shows a top perspective view of the administrator mode; B shows a partial flow diagram within the flow channel plate in the administrator mode; C shows an exploded view showing the administrator mode. When the rotating assembly 2 is in... Figure 6 In the administrator mode, the two pairs of liquid passages, 61 and 63, are connected through microchannel grooves 72 and 71, respectively. Liquid injection or drainage operations can be performed through the flow channel ports 42 or 43. Figure 6 The arrow A indicates the fluid direction when 43 is the injection hole and 42 is the drain hole. When 42 is the injection hole and 43 is the drain hole, the fluid movement direction is opposite to the arrow direction; at this time, the flow channels 41 and 44 are blocked by the rotating component body 23 to prevent user misoperation.

[0053] The following is passed Figure 6 The AC section describes the flow path under administrator mode with and without it enabled. As shown in the diagram, the pre-stored liquid is injected through injection hole 43, passing through arrows 1 and 2; through liquid hole pair 63; sinking into arrow 3; then flowing through arrows 4, 5, and 6; flowing upwards through arrow 7; sequentially through arrows 8, 9, 10, 11, and 12; then through liquid hole pair 61; through arrows 13 and 14; and finally flowing out from outlet hole 42 after filling. When administrator mode is disabled, liquid holes 63 and 61 are closed, forming a sealed chamber to store the pre-stored liquid. Administrator mode allows specific operators to add or replace solution within the sealed chamber formed by liquid holes 63 and 61.

[0054] In this disclosure, an administrator or user with administrative privileges can allow the rotating component 2 to rotate 360° by peeling off the label 21 and removing the limiting pin 22. Figure 6 When positioning, install the upper limit pin 22 so that the tail of the upper limit pin engages with the lower limit hole 51. At this time, the rotating assembly is limited to... Figure 6The position is shown. After completing the injection or drainage operation, the limit pin 22 can be removed to allow the rotating assembly to return to its original position. Figure 5 The position indicated by A or B is fitted with a limit pin 22, so that the tail of the limit pin is engaged in the arc groove 50.

[0055] This disclosure allows the connection and isolation of the first flow channel (the flow channel connecting flow channels 41 and 44) ​​to be achieved by positioning the limiting pin 22 at two positions within the arc-shaped groove (while the second flow channel is isolated at this time); when the limiting pin is within the limiting hole 51, the connection of the second flow channel (the flow channel connecting flow channels 42 and 43) can be achieved (while the first flow channel is isolated at this time). Regardless of the state, the rotating component body can block other unused flow channel openings to avoid problems caused by user misoperation.

[0056] This disclosure provides a three-position valve capable of controlling the on / off state of two flow channels. Based on this valve, both user mode and administrator mode can be implemented. This design effectively avoids the cumbersome process of using multiple valves to control two flow channels.

[0057] The technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification, provided that such combination does not contain contradictions.

[0058] Although this disclosure has been described in conjunction with embodiments, those skilled in the art will understand that the foregoing description and drawings are exemplary and not restrictive, and that this disclosure is not limited to the disclosed embodiments. Various modifications and variations are possible without departing from the spirit of this disclosure.

Claims

1. A microfluidic device, characterized in that, It includes a rotating mechanism, a rotating assembly, and a microfluidic assembly, wherein the rotating assembly and the microfluidic assembly are rotatably connected via the rotating mechanism. The rotating assembly includes a first limiting mechanism, a rotating assembly body, and a sealing layer. The limiting mechanism is detachably and fixedly connected to the rotating assembly body. The sealing layer is fitted to the rotating assembly body. The lower surface of the sealing layer is provided with microchannel grooves for fluid passage. The microfluidic assembly includes a cover plate and a flow channel plate, with the cover plate connected to the flow channel plate. The cover plate is provided with a flow channel opening, a second limiting mechanism, and a liquid passage hole. The flow channel plate is provided with multiple flow channel segments. Each flow channel opening is connected to one end of a flow channel segment, serving as an injection hole or an outlet hole. Each liquid passage hole is connected to one end of a flow channel segment. A group of liquid passage holes consisting of two or more liquid passage holes can cooperate with the microfluidic grooves on the sealing layer, so that the corresponding flow channel segments are connected. The first limiting mechanism and the second limiting mechanism cooperate to limit the relative position of the rotating component and the microfluidic component; When the rotating component rotates relative to the microfluidic component to a first position, one or more sets of liquid passage holes are connected through microchannel grooves to connect the corresponding flow channel segments, forming a through first flow channel. The two ends of the first flow channel have flow channel openings, which serve as injection holes and liquid outlet holes, respectively. When the rotating component rotates relative to the microfluidic component to a second position, one or more sets of liquid passage holes are connected through microchannel grooves to connect the corresponding flow channel segments, forming a through second flow channel. The two ends of the second flow channel have flow channel openings, which serve as injection holes and liquid outlet holes, respectively. The plurality of flow channel segments are discontinuous, including two side flow channel segments and a middle flow channel segment. The two ends of the middle flow channel segment are respectively connected to two liquid passage holes. When the rotating component is in the first position, at least one of the liquid passage holes at both ends of the middle flow channel segment is not connected by the microchannel groove, so that the middle flow channel segment forms a sealed chamber for storing the pre-stored liquid. When the rotating component is in the second position, the liquid passage holes at both ends of the middle flow channel segment are connected by the microchannel groove to form a through flow channel, so that the pre-stored liquid can be injected into or flow out of the middle flow channel segment.

2. The microfluidic device according to claim 1, characterized in that, The rotating component rotates to a third position relative to the microfluidic component, with no flow channel segments connected, thus no through flow channel is formed.

3. The microfluidic device according to claim 1 or 2, characterized in that, The through-channel includes three channel sections. The two ends of the middle channel section are connected to liquid passage holes, and the two ends of the two side channel sections are respectively connected to channel openings and liquid passage holes. The liquid passage holes connected to the middle channel section and the liquid passage holes connected to the two side channel sections form a liquid passage hole group.

4. The microfluidic device according to claim 1 or 2, characterized in that, Different flow channel sections and / or different parts of the same flow channel section are located at different depths in the flow channel plate.

5. The microfluidic device according to claim 1 or 2, characterized in that, The first limiting mechanism is a limiting pin, and the second limiting mechanism is a limiting groove or a limiting hole. The limiting pin can move in the limiting groove to limit the relative position of the rotating component and the microfluidic component; or it can be fixed in the limiting hole to lock the relative position of the rotating component and the microfluidic component.

6. The microfluidic device according to claim 1 or 2, characterized in that, The microfluidic assembly includes a sealing gasket and a sensing device located under the flow channel plate.

7. The microfluidic device according to claim 1 or 2, characterized in that, The rotating mechanism has a fixed shaft.

8. The microfluidic device according to claim 5, characterized in that, The cover plate is provided with two sets of flow channels and four pairs of liquid passage holes, and is also provided with limiting grooves and limiting holes; the limiting pin moves in the limiting groove to control the first set of flow channels to communicate through the flow channels, the first pair of liquid passage holes and the second pair of liquid passage holes on the flow channel plate; the limiting pin corresponds to the limiting hole so that the second set of flow channels to communicate through the flow channels, the third pair of liquid passage holes and the fourth pair of liquid passage holes on the flow channel plate.

9. The microfluidic device according to claim 8, characterized in that, When the limiting pin is at one end of the limiting groove, the first pair of liquid passage holes and the second pair of liquid passage holes are connected; when the limiting pin is at the other end of the limiting groove, the first pair of liquid passage holes and the second pair of liquid passage holes are not connected.

10. The microfluidic device according to claim 1 or 2, characterized in that, The sealing layer is bonded to the rotating component body by hot melting, ultrasonic welding, laser welding, or adhesive bonding.

11. The microfluidic device according to claim 1 or 2, characterized in that, The cover plate is a transparent cover plate.

12. The microfluidic device according to claim 1 or 2, characterized in that, The cover plate is attached to the flow channel plate by bonding, ultrasonic welding, laser welding, or adhesive bonding.

13. The method of using the microfluidic device according to claims 1-12, characterized in that, The method includes: 1) Remove the fixing between the first limiting mechanism and the second limiting mechanism; 2) Perform one or more of the following: i) The rotating component rotates around the rotating mechanism relative to the microfluidic component to a first position, and one or more sets of liquid passage holes are connected through the first microchannel groove to connect the corresponding flow channel segments to form a through first flow channel. The two ends of the first flow channel have flow channel openings, which serve as liquid injection holes and liquid outlet holes, respectively. ii) The rotating component rotates about the rotating mechanism relative to the microfluidic component to a second position, and one or more sets of liquid passage holes are connected through the second microchannel groove to connect the corresponding flow channel segments to form a through second flow channel. The two ends of the second flow channel have flow channel openings, which serve as liquid injection holes and liquid outlet holes, respectively. 3) The first limiting mechanism and the second limiting mechanism cooperate to limit the relative positions of the rotating component and the microfluidic component.

14. The method according to claim 13, characterized in that, 2) further includes: iii) the rotating component rotates about the rotating mechanism relative to the microfluidic component to a third position, with no flow channel segment connected, and therefore no through flow channel is formed.

15. The method according to claim 13 or 14, characterized in that, The cover plate is provided with two sets of flow channels and four pairs of liquid passage holes, as well as limiting grooves and limiting holes; In i), the limiting pin moves in the limiting groove to control the first set of flow channel openings to form a passage with the first flow channel on the flow channel plate. The first pair of liquid passage holes and the second pair of liquid passage holes on the first flow channel are connected or closed through the corresponding micro-flow channel grooves on the lower surface of the sealing layer, thereby controlling the first flow channel to be connected or closed. In ii), the limiting pin corresponds to the limiting hole so that the second set of flow channel openings and the second flow channel on the flow channel plate form a passage. The third pair of liquid passage holes and the fourth pair of liquid passage holes on the second flow channel are connected through the corresponding microchannel grooves on the lower surface of the sealing layer, thereby controlling the connection of the second flow channel.

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