Centrifugal microfluidic nucleic acid detection chip

Abstract

The invention provides a centrifugal microfluidic nucleic acid detection chip, which belongs to the technical field of microfluidics, and comprises: a chip body; the biochemical reaction module comprises a purification module, a liquid control cavity, a reaction cavity and a flow channel switching part, wherein the liquid control cavity is formed in the downstream of the purification module and is far away from the rotating center; the liquid control cavity communicates with the flow channel switching part through a first flow channel, and the middle of the first flow channel is bent towards the rotation center. The reaction cavity is communicated with the flow channel switching part through a second flow channel, and the middle part of the second flow channel is bent towards the direction of the rotating center; the nearest distance between the first flow channel and the rotating center is smaller than that between the second flow channel and the rotating center; and the flow channel switching part can be repeatedly and selectively communicated with the purification module and the liquid control cavity or communicated with the purification module, the liquid control cavity and the reaction cavity under the condition of changing centrifugal force and heating. Stable control of liquid can be achieved only through chip pipeline structure design, and the device has the advantages of being simple in structure, high in reliability and the like.

Description

Technical Field

[0001] The present application relates to the field of microfluidics technology, and in particular to a centrifugal microfluidics nucleic acid detection chip. Background Art

[0002] Due to its miniaturization, integration and high automation, microfluidic chip technology has been widely used in the field of biomedical testing (including biochemistry, immunology and molecular diagnosis). Microfluidic chip kits used to load and run various detection reagents are gradually becoming the most effective carrier form for bedside "point-of-care testing" (POCT).

[0003] In order to meet the detection needs, a fully integrated nucleic acid detection chip that integrates nucleic acid extraction and amplification detection has the advantages of fully automatic detection process, fully closed detection process, and simple manual operation. It is very suitable for realizing rapid on-site nucleic acid detection. However, the integrated microfluidic chip needs to implement various treatments of liquids, including sealed isolation of liquids, control and sorting of fluid direction, and precise flow control. The implementation of these operations often requires the design of multiple valves including rotary valves, Coriolis valves, mechanical valves, and paraffin valves, and the instruments need to cooperate to operate in order to achieve the above functions. In addition, the dynamic balance during the centrifugation process is crucial to the reliability of the microfluidic chip. Therefore, the integrated chip is often very complex in structure and difficult to use on a large scale.

[0004] The Chinese utility model patent with the announcement number CN220071688U proposes a centrifugal microfluidic chip and detection equipment, which discloses the use of paraffin valves to achieve the sealing of the chip fluid pipeline. When it needs to be opened, the chip only needs to be heated, and the valve can be opened after the paraffin melts. However, it can only control the on and off of the fluid, and can only achieve on and off once; in addition, a set of paraffin valves cannot achieve the switching and diversion of multiple liquids. The Chinese invention patent with the publication number CN116532174A proposes a microfluidic chip with a rotary valve and a control method thereof, which can not only achieve the sequential connection of multiple pipelines, but also achieve the sealing between each pipeline. Its valve body structure is composed of valve seat, rotor, sealing gasket, valve body and other structures. The structure is complex and the cost is high, and it requires the instrument to rotate the rotor to achieve it. The Chinese invention patent with announcement number CN111218395B proposes a full-process biological detection device, which discloses a Coriolis valve structure and uses the Coriolis force generated during the rotation of the chip to achieve liquid deflection, thereby controlling the direction of the liquid, but it has the following problems: 1. It can only control the liquid flow to deflect in two directions, to the left or to the right, so its use is limited; 2. Under theoretical conditions, the liquid is deflected by the Coriolis force, but during the actual rotation start and stop process, the imbalance of the fluid inside the chip causes vibration, which will have a very large impact on the deflection of the liquid flow, resulting in easy misalignment of the liquid flow and unstable flow control; 3. The Coriolis valve structure is in a fully open state, so it can only control the direction of the liquid, and cannot achieve sealing of the liquid path.

[0005] Therefore, for centrifugal microfluidic chips, the following problems need to be solved urgently: how to achieve precise flow control of liquid without valve control during the centrifugation process of the chip while achieving fluid sealing and selection of liquid flow direction. Summary of the invention

[0006] The purpose of the present invention is to provide a centrifugal microfluidic nucleic acid detection chip, which can achieve stable control of liquid only by chip pipeline structure design, and has the advantages of simple structure, low cost, high reliability, etc.

[0007] The present invention adopts the following technical solution: A centrifugal microfluidic nucleic acid detection chip comprises: a chip body; a biochemical reaction module, wherein the biochemical reaction module is at least one and is arranged on the chip body; the biochemical reaction module comprises a purification module, a liquid control chamber, a reaction chamber and a flow channel switching part which are arranged downstream of the purification module and away from a rotation center; the liquid control chamber is connected to the flow channel switching part through a first flow channel, and the middle part of the first flow channel is bent toward the rotation center; the reaction chamber is connected to the flow channel switching part through a second flow channel, and the middle part of the second flow channel is bent toward the rotation center; the closest distance between the first flow channel and the rotation center is smaller than the closest distance between the second flow channel and the rotation center; the flow channel switching part can repeatedly and selectively connect the purification module with the liquid control chamber or connect the purification module, the liquid control chamber and the reaction chamber under the conditions of changing centrifugal force and heating.

[0008] Furthermore, the flow channel switching part includes: a switching pipe, which is arranged gradually away from the rotation center, the proximal end of the switching pipe is connected to the purification module, a phase change material is arranged in the switching pipe, and the phase change material becomes a liquid after heating; an energy storage chamber, the distal end of the switching pipe is connected to the energy storage chamber.

[0009] Furthermore, the flow channel switching portion also includes a bent connecting pipe, one end of which is connected to the distal end of the switching pipe, and the other end of which is connected to a side of the energy storage chamber away from the rotation center.

[0010] Furthermore, different heating conditions are set for different parts of the flow channel switching portion.

[0011] Furthermore, the heating part includes: a heat-conducting copper plate, which has a slow heating zone and a uniform heating zone, and the slow heating zone is located on the side of the phase change material away from the energy storage chamber and close to the first flow channel; a heating source, which is located in the uniform heating zone and close to the side away from the rotation center.

[0012] Furthermore, the heat-averaging zone and the slow-heating zone are made of an integral copper plate and are located below the phase change material; the closer the projection of the copper plate in the slow-heating zone on the switching pipe is to the end sealing point, the farther it is from the switching pipe.

[0013] Furthermore, the length of the slow heating zone is 2-4 times the diameter of the switching pipe, and the projection of one end of the slow heating zone away from the uniform heating zone on the heat exchange pipe completely covers the end sealing point; the angle α between the uniform heating zone and the slow heating zone is related to the diameter D of the switching pipe, ; in is the reference diameter, the value range is 0.5-1.0mm, .

[0014] Furthermore, the heat-averaging zone and the slow-heating zone are made of an integral copper plate, the heat-averaging zone and the slow-heating zone are located on the same plane, the slow-heating zone includes a heat-conducting portion arranged on both sides of the end of the heat-averaging zone close to the end sealing point, and the closer the heat-conducting portion is to the end sealing point, the narrower its width; the heat-conducting portion is located on both sides of the switching pipe, and the inner edges of the heat-conducting portions on both sides are open and face the proximal end.

[0015] Furthermore, the first flow channel and the second flow channel are located on the same side of the switching pipe.

[0016] Furthermore, the switching pipe includes a first switching pipe and a second switching pipe, the first switching pipe extends radially along the rotation center, and the upper end is connected to the purification module, and the lower end is connected to the second switching pipe; a first flow channel is provided at the upper part of the interface between the first switching pipe and the second switching pipe, and the opening of the first flow channel is provided and connected to the side wall of the first switching pipe; compared with the interface between the first switching pipe and the second switching pipe, the opening is closer to the rotation center along the radial direction of the rotation center.

[0017] The present invention provides a centrifugal microfluidic nucleic acid detection chip, which has the following beneficial technical effects compared with the prior art: (1) The centrifugal microfluidic nucleic acid detection chip provided by the present invention realizes the control of at least two valve groups by controlling the two conditions of centrifugal force and heating, thereby eliminating manual operation, reducing labor intensity and the possibility of operational errors; secondly, at least two valve groups realize at least three working states, thereby improving the application scenarios of the product, and the application scenarios include: (1) when the purification module is working normally, the purification module is not connected to the liquid control chamber (at this time, the purification module, the liquid control chamber and the reaction chamber are also not connected), thereby ensuring the normal operation of the purification module; (2) waste liquid is discharged, at this time the purification module is connected to the liquid control chamber; (3) the cleaned nucleic acid is transported to the reaction pool, at this time the purification module, the liquid control chamber and the reaction chamber are connected; (4) during the reaction process, the purification module, the liquid control chamber and the reaction chamber are not connected, and the reaction environment is sealed to prevent pollution of the reaction environment and cause inaccurate detection results.

[0018] (2) High reliability. The chip fluid structure is simple, and there are no other redundant moving parts except the chip body. Secondly, the cost is low. The chip has few structural parts and low cost. The chip fluid structure is simple and the manufacturing cost is low. The chip has low requirements for supporting instruments, and the instrument structure is simple and low cost. Finally, miniaturization is achieved. The arrangement of the liquid control cavity along the circumference can minimize the size of the liquid control cavity in the radial direction of the chip, thereby reducing the chip area. The design of the flow control pipeline can not only realize the sorting of liquids, but also realize the sealing of multiple chambers, reducing the fluid structure design, thereby realizing the miniaturization of the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 A structural diagram of a centrifugal microfluidic nucleic acid detection chip provided by an embodiment of the present invention; Figure 2 A schematic diagram of the purification module structure provided in an embodiment of the present invention; Figure 3 The specific structure of the pipeline switching unit provided by the embodiment of the present invention; Figure 4 A schematic diagram of the structure of a heating unit provided by an embodiment of the present invention; Figure 5 for Figure 4 AA section view; Figure 6 A schematic diagram of another heating unit structure provided by an embodiment of the present invention; Figure 7 Another schematic diagram of a heating unit provided by an embodiment of the present invention; Figure 8 A structural diagram of another centrifugal microfluidic nucleic acid detection chip provided by an embodiment of the present invention; Fig. 9 A partial enlarged view of a switching pipeline provided in an embodiment of the present invention; Fig.10 The first working state of the pipeline switching unit provided in the embodiment of the present invention; Fig.11 The second working state of the pipeline switching unit provided in the embodiment of the present invention; Fig.12 The third working state of the pipeline switching unit provided in the embodiment of the present invention; Fig.13 This is the fourth working state of the pipeline switching unit provided in the embodiment of the present invention.

[0021] Figure numerals: 1. chip body; 2. biochemical reaction module; 20. purification module; 200. cleaning chamber; 201. elution chamber; 202. sample chamber; 203. buffer chamber; 204. nucleic acid extraction chamber; 21. liquid control chamber; 210. first flow channel; 22. reaction chamber; 220. second flow channel; 23. flow channel switching part; 230. switching pipeline; 2300. first switching pipeline; 2301. second switching pipeline; 2302. interface; 231. energy storage chamber; 2311. energy storage chamber; 2310. piston; 232. phase change material; 2321. liquid material; 2320. solid material; 233. end sealing point; 234. connecting pipeline; 30. thermal conductive copper plate; 300. slow heating zone; 3000. inner edge of thermal conductive part; 301. heat equalization zone; 40. gas exchange chamber. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0025] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

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

[0027] The embodiment of the present invention discloses a centrifugal microfluidic nucleic acid detection chip, such as Figure 1 As shown, it includes: a chip body 1; a biochemical reaction module 2, at least one of which is arranged on the chip body 1; the biochemical reaction module 2 includes a purification module 20, a liquid control chamber 21, a reaction chamber 22 and a flow channel switching part 23 arranged downstream of the purification module 20 and away from the rotation center; the liquid control chamber 21 is connected to the flow channel switching part 23 through a first flow channel 210, and the middle part of the first flow channel 210 is bent toward the rotation center O; the reaction chamber 22 is connected to the flow channel switching part 23 through a second flow channel 220, and the middle part of the second flow channel 220 is bent toward the rotation center O; the closest distance between the first flow channel 210 and the rotation center O is smaller than the closest distance between the second flow channel 220 and the rotation center O; the flow channel switching part 23 can repeatedly and selectively connect the purification module 20 with the liquid control chamber 21 or connect the purification module 20, the liquid control chamber 21 and the reaction chamber 22 under the conditions of changing centrifugal force and heating.

[0028] Specifically, the liquid control chamber 21 can be any one of the steps required for the biochemical reaction, and is used for liquid transfer or reaction. In the embodiment of the present invention, the liquid control chamber 21 is a chamber for collecting waste liquid. The purification module 20 is used for nucleic acid purification, and the nucleic acid is cleaned by a cleaning liquid, and the cleaned waste liquid is discharged into the liquid control chamber 21. The reaction chamber 22 is a functional cavity in the biochemical reaction module 2, and corresponding reagents or magnetic beads for accelerating the reaction can be set inside it based on the function selection.

[0029] The centrifugal microfluidic nucleic acid detection chip provided by the present invention, firstly, realizes automatic control of at least two valve groups by controlling the two conditions of centrifugal force and heating, thereby eliminating manual operation, reducing labor intensity and the possibility of operating errors; secondly, realizes three valve functions: a. realizes mutual sealing and isolation of each chamber; b. realizes selective connection of each chamber; c. realizes repeated switching function; in addition, at least two valve groups realize at least three working states, thereby improving the application scenarios of the product, and the application scenarios include: (1) when the purification module 20 works normally, the purification module 20 is not connected to the liquid control chamber 21 (at this time, the purification module 20, the liquid control chamber 21 and the reaction chamber 22 are also not connected), ensuring the normal operation of the purification module 20; (2) waste liquid is discharged, at this time the purification module 20 is connected to the liquid control chamber 21; (3) the cleaned nucleic acid is transported to the reaction pool, at this time the purification module 20, the liquid control chamber 21 and the reaction chamber 22 are connected; (4) during the reaction process, the purification module 20, the liquid control chamber 21 and the reaction chamber 22 are not connected, the reaction environment is sealed, and the pollution of the reaction environment is prevented to prevent inaccurate detection results.

[0030] Specifically, Figure 2 As shown, the purification module 20 in the present invention includes a cleaning chamber 200, an elution chamber 201, a sample chamber 202, a buffer chamber 203 and a nucleic acid extraction chamber 204; the cleaning chamber 200, the elution chamber 201 and the sample chamber 202 are arranged in a circumferential direction with the rotation center O as the center, the sample chamber 202 is located between the cleaning chamber 200 and the elution chamber 201, a buffer chamber 203 is arranged below the sample chamber 202, and is connected to the sample chamber 202, the cleaning chamber 200 and the elution chamber 201 respectively, and a nucleic acid extraction chamber 204 is arranged downstream of the buffer chamber 203. The buffer chamber 203 is arranged below the sample chamber 202, shortening the distance between the sample chamber 202 and the buffer chamber 203, ensuring that the flow channel connecting the two is short, so that as much nucleic acid in the sample as possible is retained to prevent some nucleic acid substances from adhering to the flow channel.

[0031] The cleaning chamber 200, elution chamber 201, sample chamber 202, buffer chamber 203 and nucleic acid extraction chamber 204 are functional chambers respectively. The cleaning chamber 200 stores cleaning solution, the elution chamber 201 stores elution solution, the sample chamber 202 is provided with a sample addition hole, and the sample to be detected is added to the sample chamber 202 through the sample addition hole. The nucleic acid extraction chamber 204 has a material for nucleic acid adsorption, such as a porous biomacromolecule adsorption material. The porous biomacromolecule adsorption material is: silicon oxide fibers or particles or loose membranes, ion exchange resins, silicon oxide nanoparticles, magnetic particle materials with silicon oxide on the surface, porous materials coated with silicon oxide nanomaterials on the surface, porous materials coated with chitosan on the surface, or other various porous materials with silicon hydroxyl modification on the surface.

[0032] The above-mentioned porous biomacromolecule adsorption material is in the shape of a loose film, a sheet or a particle, wherein the loose film can be a single-layer film or a multi-layer film, and can contain sheets of different sizes or particles of different particle sizes; the fluid cavity can be filled with the same type of porous biomacromolecule adsorption material, or it can be filled with different types of porous biomacromolecule adsorption materials.

[0033] The distal end of the nucleic acid extraction cavity 204 is in a contracted structure, which may be, but not limited to, a triangle, a circle, an inverted trapezoid, a rhombus, etc. In the embodiment of the present invention, the nucleic acid extraction cavity 204 is in a rhombus structure.

[0034] It should be noted that the closest distance between the first flow channel 210 and the rotation center is smaller than the closest distance between the second flow channel 220 and the rotation center. Figure 2 As shown, the shortest distance between the first flow channel 210 and the rotation center O is S1, and the shortest distance between the second flow channel 220 and the rotation center O is S2, S1<S2. Through the above arrangement, when the purification module 20, the liquid control chamber 21 and the reaction chamber 22 are connected, it is ensured that the cleaned nucleic acid flows out of the purification module 20 and then flows into the reaction chamber 22 through the flow channel switching part 23 and the second flow channel 220. For the convenience of control, the distance difference between S1 and S2 can be increased to facilitate the subsequent control of the rotation speed.

[0035] In the embodiment of the present invention, six reaction chambers 22 are provided, and the number of reaction chambers 22 can be reduced or increased based on test requirements.

[0036] Specifically, Figure 3 As shown, the flow channel switching part 23 includes: a switching pipe 230, the switching pipe 230 is arranged gradually away from the rotation center O, the proximal end of the switching pipe 230 is connected to the purification module 20, a phase change material 232 is arranged in the switching pipe 230, and the phase change material 232 becomes liquid after heating; an energy storage chamber 231, the distal end of the switching pipe 230 is connected to the energy storage chamber 231.

[0037] In the present invention, the energy storage chamber 231 is an energy storage structure, and its function is that when the phase change material 232 is converted into a liquid state after being heated, it can squeeze the energy storage chamber 231 under the action of centrifugal force to form potential energy. When the rotation speed of the microfluidic detection chip is reduced, the potential energy of the energy storage chamber 231 is released to push the liquid phase change material 232 to move in a direction close to the rotation center O. It should be pointed out that when the energy storage chamber 231 stores energy, the liquid phase change material 232 can partially enter the energy storage chamber 231 or not enter the energy storage chamber 231. Figure 3 The phase change material 232 in FIG. 2 shows a situation in which the phase change material 232 enters the energy storage chamber 231 .

[0038] Specifically, Figure 3As shown, the energy storage chamber 231 includes an energy storage chamber 2311 and a piston 2310 that can be slidably and sealedly connected to the energy storage chamber 2311. Under the action of centrifugal force, the liquid phase change material 232 squeezes the piston 2310, thereby compressing the sealed space formed by the energy storage chamber 2311 and the piston 2310 to form potential energy.

[0039] In another embodiment, if Figure 2 The flow channel switching portion 23 shown in the figure also includes a bent connecting pipe 234, one end of which is connected to the distal end of the switching pipe 230, and the other end of which is connected to the side of the energy storage chamber 231 away from the rotation center O. In this case, there is no need to set a piston in the energy storage chamber 231, the structure is simple, and the manufacturing cost is saved. Under the action of centrifugal force, the liquid phase change material 232 enters the energy storage chamber 231, and forms a sealed cavity with the energy storage chamber 231. Under the action of centrifugal force, the energy storage chamber 231 is compressed to store energy.

[0040] The phase change material 232 in the present invention can be a wax, for example, the wax can be paraffin, microcrystalline wax, synthetic wax or natural wax. Alternatively, the phase change material 232 can also be a gel or a thermoplastic resin. The gel can be polyacrylamide, polyacrylate, polymethacrylate, or polyvinylamine. Thermoplastic resins can be cyclic olefin copolymers (COC), polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), polyoxymethylene (POM), perfluoroalkoxy (PFA), polyvinyl chloride (PVC), polypropylene (PP), polyethylene terephthalate (PET), polyetheretherketone (PEEK), polyacrylate (PA), polysulfone (PSU) or polyethylene diene fluoride (PVDF), etc.

[0041] The above scheme can be used for the detection of biological information, but there is still room for optimization. For example, when the first flow channel 210 and the switching pipe 230 are opened, the purification module 20 is connected to the liquid control chamber 21. Under the action of centrifugal force, there is a possibility that the waste liquid is partially rushed into the liquid phase change material 232 under the action of centrifugal force, causing the liquid phase change material 232 to be contaminated. When the purified nucleic acid flows through the switching pipe 230 and the second flow channel 220 into the reaction chamber 22, the nucleic acid contacts the contaminated phase change material 232, and there is a possibility that the purified nucleic acid may be contaminated. In order to further improve the accuracy of the detection results, the present invention also proposes the following scheme.

[0042] Specifically, different heating conditions are set for different parts of the flow channel switching part 23. The phase change material 232 near the first flow channel 210 is slowly heated to prevent its viscosity from being too low, so that the waste liquid can easily rush into the phase change material 232, and other areas are uniformly heated to facilitate flow.

[0043] Specifically, Figure 4 As shown, the heating part includes: a heat-conducting copper plate 30, the heat-conducting copper plate 30 has a slow-heating zone 300 and a uniform heat zone 301, the slow-heating zone 300 is located on the side of the phase change material 232 away from the energy storage chamber 231 and close to the first flow channel 210; a heating source, the heating source is located in the uniform heat zone 301 and close to the side away from the rotation center. The slow-heating zone 300 is slow-heating, so the viscosity of the phase change material 232 there is relatively large, and it is difficult for waste liquid to rush into the liquid phase change material 232, thereby preventing contamination of the phase change material 232.

[0044] like Figure 5 As shown, the heat-averaging zone 301 and the slow-heating zone 300 are made of an integral copper plate, which is located below the phase-change material 232; the closer the projection of the copper plate located in the slow-heating zone 300 on the switching pipe 230 is to the end seal point 233, the farther it is from the switching pipe 230. The end seal point 233 is the end point of the phase-change material 232 in the switching pipe 230. Since the closer to the end seal point 233, the farther the distance between the copper plate and the phase-change material 232, the heating capacity of the phase-change material 232 corresponding to the slow-heating zone 300 will be weakened, the viscosity of the phase-change material 232 corresponding to the slow-heating zone 300 is relatively large, and the waste liquid is less likely to contaminate the phase-change material.

[0045] like Figure 5 As shown, the length L of the slow heating zone 300 is 2-4 times the diameter of the switching pipe 230, and the projection of one end of the slow heating zone 300 away from the uniform heating zone 301 on the heat exchange pipe completely covers the end sealing point 233; the angle α between the uniform heating zone 301 and the slow heating zone 300 is related to the diameter D of the switching pipe 230, ; in is the reference diameter, the value range is 0.5-1.0mm, .

[0046] It should be noted that when the cross section of the switching pipe 230 is not circular, the equivalent diameter can be calculated by the cross-sectional area thereof.

[0047] Another preferred embodiment of the present invention is as follows Figure 6As shown, the heat-averaging zone 301 and the slow-heating zone 300 are made of an integral copper plate, and the heat-averaging zone 301 and the slow-heating zone 300 are located on the same plane. The slow-heating zone 300 includes a heat-conducting portion arranged on both sides of the end of the heat-averaging zone 301 near the end seal point 233, and the closer the heat-conducting portion is to the end seal point 233, the narrower its width; the heat-conducting portion is located on both sides of the switching pipe 230, and the inner edges 3000 of the heat-conducting portions on both sides are open and face the proximal end. The above-mentioned arrangement ensures that the phase change material 232 of the slow-heating zone 300 is slowly heated. On the other hand, the inner edges 3000 of the heat-conducting portions on both sides are open and face the proximal end, which, on the one hand, increases the circulation speed of the liquid phase change material 232, and on the other hand, ensures the existence of part of the solid state, so that the waste liquid cannot contaminate the paraffin.

[0048] Its principle is as follows Figure 7 As shown, since the inner edge 3000 of the heat conducting portion on both sides is open and toward the proximal end, part of the phase change material 232 is in a solid phase, that is, liquid material 2321 and solid material 2320, and the inner edge 3000 of the heat conducting portion is open so that the lower part of the solid material 2320 is "V" shaped. Since the contact area between the two sides of the solid material 2320 and the switching pipe 230 is small, the resistance value is small. On the other hand, the solid material further prevents the waste liquid from contaminating it, making the detection result more accurate.

[0049] In another preferred embodiment, Figure 8 As shown, the first flow channel 210 and the second flow channel 220 are located on the same side of the switching pipe 230. The size of the biochemical reaction module 2 is further reduced, so that the chip body 1 can carry more biochemical reaction modules 2.

[0050] When the purification module 20, the liquid control chamber 21 and the reaction chamber 22 are connected, if the rotation speed is not appropriate, there is a possibility that the purified nucleic acid enters the liquid control chamber 21. In order to prevent the above problem, Fig. 9 As shown, the switching pipe 230 includes a first switching pipe 2300 and a second switching pipe 2301, the first switching pipe 2300 extends along the radial direction R of the rotation center, the upper end is connected to the purification device, and the lower end is connected to the second switching pipe 2301; a first flow channel 210 is arranged on the upper part of the interface 2302 between the first switching pipe 2300 and the second switching pipe 2301, and the opening of the first flow channel 210 is connected to the side wall of the first switching pipe 2300; compared with the interface 2302 between the first switching pipe 2300 and the second switching pipe 2301, the opening is closer to the rotation center along the radial direction of the rotation center.

[0051] The nucleic acid detection chip proposed in the present invention is also provided with a gas exchange system, such as Figure 1As shown, the gas exchange system includes a gas exchange chamber 40, and the gas exchange chamber 40 is divided into two connected parts, which are respectively located between the cleaning chamber 200 and the sample chamber 202, and between the elution chamber 201 and the sample chamber 202. The lower part of the gas exchange chamber 40 is respectively connected to the delivery channels of the cleaning chamber 200 and the elution chamber 201; the upper part of the gas exchange chamber 40 is respectively connected to the proximal ends of the reaction chamber 22 and the liquid control chamber 21 through channels.

[0052] The working principle of the centrifugal microfluidic nucleic acid detection chip is as follows: Fig.10 As shown, before the experiment begins, a phase change material 232 (black) is provided in the switching pipe 230 of the flow channel switching part 23, so as to achieve the sealing of the purification module 20, the liquid control chamber 21 and the reaction chamber 22. After the experiment begins, the heating is started, the phase change material 232 in the switching pipe 230 melts (turns gray), the centrifugation is started, and the centrifugal speed V1 is applied. The melted phase change material 232 in the switching pipe 230 enters the energy storage chamber 231 under the action of the centrifugal force and squeezes the space in the energy storage chamber 231, as shown in FIG. Fig.11 As shown, the first flow channel 210 connected to the liquid control chamber 21 is opened, and the liquid in the purification module 20 enters the liquid control chamber 21 through the first flow channel 210. When the liquid in the purification module 20 is completely centrifuged to the liquid control chamber 21, the centrifugation is stopped, and the compressed gas in the energy storage chamber 231 pushes out the melted liquid phase change material 232, and the first flow channel 210 is closed again. After cooling, the seal is achieved again, as shown in FIG. Fig.12 Similarly, the heating is started again to melt the phase change material 232 in the flow control pipe, and the centrifugal speed V2 is applied. The melted phase change material 232 enters the energy storage chamber 231 again under the action of centrifugal force, and the first flow channel 210 connected to the liquid control chamber 21 and the second flow channel 220 connected to the reaction chamber 22 are opened. Since the liquid outlet of the second flow channel 220 is farther away from the rotation center than the liquid outlet of the first flow channel 210, and the highest point of the second flow channel 220 is farther away from the rotation center than the highest point of the first flow channel 210, the liquid in the purification module 20 enters the reaction chamber 22 through the second flow channel 220, as shown in FIG. Fig.13 When the liquid in the purification module 20 is completely transferred to the reaction chamber 22, the centrifugation is stopped, and the compressed gas in the energy storage chamber 231 pushes out the melted liquid phase change material 232, re-sealing the first flow channel 210 and the second flow channel 220, and sealing is achieved again after cooling, as shown. Fig.12 shown.

[0053] It should be pointed out that the above working principles are all about melting first and then centrifugation. Centrifugation can also be performed first and heating can be performed during the centrifugation process. This method does not require the phase change material 232 to be completely melted, and the corresponding flow channels can be connected under the action of centrifugal force. Based on the heating unit proposed in this application, the effect of heating during the centrifugation process is better.

[0054] The specific experimental process is: 1. Add nucleic acid sample into the sample chamber 202 through the sample adding port; 2. Start centrifugation at 2000 rpm, the sample enters the nucleic acid extraction chamber 204 through the buffer chamber 203, the nucleic acid sample and the magnetic beads pre-stored in the nucleic acid extraction chamber 204 are fully mixed, and the centrifugation is stopped after the magnetic beads complete the nucleic acid adsorption; 3. Start heating until the phase change material 232 in the switching pipe 230 melts, and start centrifugation at 2200rpm at the same time. The melted phase change material 232 in the flow control pipe enters the energy storage chamber 231 under the action of centrifugal force, and the pipeline between the nucleic acid extraction chamber 204 and the liquid control chamber 21 is connected. The waste liquid in the nucleic acid extraction chamber 204 enters the liquid control chamber 21 under the action of centrifugal force, and then stop centrifugation and cool. The phase change material 232 completes the sealing of the nucleic acid extraction chamber 204 and the liquid control chamber 21 again.

[0055] 4. Start the centrifugation again at 2600 rpm. The cleaning solution in the cleaning chamber 200 enters the nucleic acid extraction chamber 204 through the buffer chamber 203. After the cleaning solution fully cleans the magnetic beads in the nucleic acid extraction chamber 204, stop the centrifugation. 5. Repeat step 3, and the waste liquid after the magnetic bead washing enters the liquid control chamber 21, then stop centrifugation and cool, and the phase change material 232 completes the sealing of the nucleic acid extraction chamber 204 and the liquid control chamber 21 again.

[0056] 6. Start centrifugation again at 3200 rpm. The liquid in the elution chamber 201 enters the nucleic acid extraction chamber 204 through the buffer chamber 203. The eluent completes elution of the nucleic acid adsorbed on the surface of the magnetic beads in the nucleic acid extraction chamber 204 and then stops centrifugation. 7. Start heating again until the phase change material 232 in the switching pipe 230 melts, and start centrifugation at 3000rpm. The melted phase change material 232 in the flow control pipe enters the energy storage chamber 231 more under the action of centrifugal force, and the pipes between the nucleic acid extraction chamber 204 and the liquid control chamber 21 and the reaction chamber 22 are connected at the same time. However, since the inlet of the liquid outlet pipe connected to the reaction chamber 22 is farther away from the rotation center than the inlet of the liquid outlet pipe connected to the liquid control chamber 21, the nucleic acid eluent enters each reaction chamber 22 in turn under the action of centrifugal force. Then stop the centrifugation and cool, and the phase change material 232 completes the sealing of the nucleic acid extraction chamber 204, the liquid control chamber 21 and the reaction chamber 22 again.

[0057] 8. Nucleic acid amplification, collecting real-time fluorescence curves.

[0058] The above description is only an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A centrifugal microfluidic nucleic acid detection chip, characterized in that: include: Chip body; A biochemical reaction module, the number of the biochemical reaction module is at least one and the biochemical reaction module is arranged on the chip body; The biochemical reaction module includes a purification module, a liquid control chamber, a reaction chamber and a flow channel switching part arranged downstream of the purification module and away from the rotation center; the liquid control chamber is connected to the flow channel switching part through a first flow channel, and the middle part of the first flow channel is bent toward the rotation center; the reaction chamber is connected to the flow channel switching part through a second flow channel, and the middle part of the second flow channel is bent toward the rotation center; the shortest distance between the first flow channel and the rotation center is smaller than the shortest distance between the second flow channel and the rotation center; The flow channel switching part can repeatedly and selectively connect the purification module with the liquid control chamber or connect the purification module, the liquid control chamber and the reaction chamber under the conditions of changing the centrifugal force and heating.

2. The centrifugal microfluidic nucleic acid detection chip according to claim 1, characterized in that: The flow channel switching unit includes: A switching pipeline, wherein the switching pipeline is gradually arranged away from the rotation center, the proximal end of the switching pipeline is connected to the purification module, and a phase change material is arranged in the switching pipeline, and the phase change material becomes liquid after being heated; An energy storage chamber, the distal end of the switching pipe is connected to the energy storage chamber.

3. The centrifugal microfluidic nucleic acid detection chip according to claim 2, characterized in that: The flow channel switching part also includes a bent connecting pipe, one end of which is connected to the distal end of the switching pipe, and the other end of which is connected to a side of the energy storage chamber away from the rotation center.

4. The centrifugal microfluidic nucleic acid detection chip according to claim 2 or 3, characterized in that: Different heating conditions are set for different parts of the flow channel switching part.

5. The centrifugal microfluidic nucleic acid detection chip according to claim 4, characterized in that: The heating section includes: A heat-conducting copper plate, wherein the heat-conducting copper plate has a slow-heating zone and a heat-averaging zone, wherein the slow-heating zone is located on a side of the phase change material away from the energy storage chamber and close to the first flow channel; A heating source is located in the heat-averaging zone and close to a side away from the rotation center.

6. The centrifugal microfluidic nucleic acid detection chip according to claim 5, characterized in that: The heat-saturating zone and the slow-heating zone are made of an integrated copper plate and are located below the phase change material; The closer the projection of the copper plate located in the slow heating zone on the switching pipe is to the end sealing point, the farther it is from the switching pipe.

7. The centrifugal microfluidic nucleic acid detection chip according to claim 6, characterized in that: The length of the slow heating zone is 2-4 times the diameter of the switching pipe, and the projection of one end of the slow heating zone away from the uniform heating zone on the heat exchange pipe completely covers the end sealing point; The angle α between the uniform heating zone and the slow heating zone is related to the diameter D of the switching pipe. ； in is the reference diameter, the value range is 0.5-1.0mm, .

8. The centrifugal microfluidic nucleic acid detection chip according to claim 5, characterized in that: The heat-saturating zone and the slow-heating zone are made of an integral copper plate. The heat-saturating zone and the slow-heating zone are located on the same plane. The slow-heating zone includes a heat-conducting portion arranged on both sides of the end of the heat-saturating zone near the end sealing point. The closer the heat-conducting portion is to the end sealing point, the narrower its width; The heat conducting parts are located at two sides of the switching pipe, and the inner edges of the heat conducting parts at the two sides are open and face the proximal end.

9. The centrifugal microfluidic nucleic acid detection chip according to claim 2, characterized in that: The first flow channel and the second flow channel are located on the same side of the switching pipe.

10. The centrifugal microfluidic nucleic acid detection chip according to claim 2, characterized in that: The switching pipeline includes a first switching pipeline and a second switching pipeline, wherein the first switching pipeline extends radially along the rotation center, and the upper end of the first switching pipeline is connected to the purification module, and the lower end of the first switching pipeline is connected to the second switching pipeline; A first flow channel is arranged at the upper part of the interface between the first switching pipe and the second switching pipe, and the opening of the first flow channel is arranged to be connected to the side wall of the first switching pipe; compared with the interface between the first switching pipe and the second switching pipe, the opening is closer to the rotation center along the radial direction of the rotation center.

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