A centrifugal microfluidic nucleic acid detection chip

Abstract

The present invention provides a centrifugal microfluidic nucleic acid detection chip, belonging to the field of microfluidic technology, comprising: a chip body; a biochemical reaction module, the biochemical reaction module including a purification module, a liquid control cavity, a reaction cavity and a flow channel switching part which is arranged downstream of the purification module and away from the rotation center; the liquid control cavity is communicated with the flow channel switching part through a first flow channel, and the middle part of the first flow channel is bent towards the rotation center direction; 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 rotation center direction; the closest distance between the first flow channel and the rotation center is less than the closest distance between the second flow channel and the rotation center; under the conditions of changing centrifugal force and heating, the flow channel switching part can repeatedly and selectively communicate the purification module with the liquid control cavity or communicate the purification module, the liquid control cavity and the reaction cavity. The present invention can realize stable control of liquid only through the design of the chip pipeline structure, and has the advantages of simple structure, high reliability, etc.

Description

Technical Field

[0001] This application relates to the field of microfluidic technology, and particularly to a centrifugal microfluidic nucleic acid detection chip. Background Art

[0002] Due to characteristics such as miniaturization, integration, and high automation, microfluidic chip technology has been widely used in the field of biomedical detection (including biochemical, immunological, and molecular diagnostics, etc.). Microfluidic chip kits for loading and running various detection reagents are gradually becoming the most effective carrier form for realizing "point-of-care testing" (POCT) at the bedside.

[0003] In order to meet the detection requirements, a fully integrated nucleic acid detection chip that integrates nucleic acid extraction and amplification detection has the advantages of fully automatic detection process, fully enclosed detection process, and simple manual operation, and is very suitable for realizing on-site rapid nucleic acid detection. However, an integrated microfluidic chip needs to perform various treatments on liquids, including liquid sealing and isolation, fluid direction control and sorting, and precise flow control. The implementation of these operations often requires the design of various valves including rotary valves, Coriolis valves, mechanical valves, and paraffin valves, and requires the cooperation of instruments to achieve the above functions. In addition, dynamic balance during centrifugation is crucial for the reliability of the microfluidic chip. Therefore, integrated chips often have a very complex structure and are difficult to be used on a large scale.

[0004] The Chinese utility model patent with the publication number CN220071688U proposes a centrifugal microfluidic chip and a detection device, which discloses the use of a paraffin valve to seal the fluid pipeline of the chip. When it needs to be opened, only heat the chip, 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 group 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 its control method, which can not only achieve the sequential connection of multiple pipelines but also achieve the sealing between each pipeline. Its valve body structure consists of a valve seat, a rotor, a gasket, a valve body, etc., with a complex structure, high cost, and requires an instrument to rotate the rotor to achieve. The Chinese invention patent with the publication number CN111218395B proposes a full-process biological detection device, which discloses a Coriolis valve structure. The deflection of the liquid is achieved by using the Coriolis force generated during the rotation of the chip, so as to control the direction of the liquid. However, 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 deflects under the action of the Coriolis force, but in the actual rotation start and stop processes, the imbalance of the fluid inside the chip causes vibrations, which will have a very large impact on the deflection of the liquid flow, resulting in easy misdirection of the liquid flow and unstable flow control; 3. The Coriolis valve structure is in a fully open state, so it can only achieve the control of the liquid direction and cannot achieve the sealing of the liquid path.

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

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

[0007] The present invention adopts the following technical solutions:

[0008] A centrifugal microfluidic nucleic acid detection chip, comprising: a chip body; a biochemical reaction module, at least one biochemical reaction module is provided on the chip body; the biochemical reaction module includes a purification module, a liquid control cavity, a reaction cavity and a flow path switching part which are arranged downstream of the purification module and away from the rotation center; the liquid control cavity is communicated with the flow path switching part through a first flow path, and the middle part of the first flow path is bent towards the rotation center direction; the reaction cavity is communicated with the flow path switching part through a second flow path, and the middle part of the second flow path is bent towards the rotation center direction; the closest distance of the first flow path from the rotation center is less than the closest distance of the second flow path from the rotation center; under the conditions of changing centrifugal force and heating, the flow path switching part can repeatedly and selectively communicate the purification module with the liquid control cavity or communicate the purification module, the liquid control cavity and the reaction cavity.

[0009] Further, the flow path switching part includes: a switching pipeline, the switching pipeline is gradually arranged away from the rotation center, the proximal end of the switching pipeline is connected with 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 pipeline is connected with the energy storage chamber.

[0010] Further, the flow path switching part further includes a bent connecting pipeline, one end of the connecting pipeline is communicated with the distal end of the switching pipeline, and the other end of the connecting pipeline is connected with the side of the energy storage chamber away from the rotation center.

[0011] Further, different heating conditions are set for different parts of the flow path switching part.

[0012] Further, the heating part includes: a heat-conducting copper plate, the heat-conducting copper plate has a slow-heating area and a heat-uniforming area, the slow-heating area is located on the side of the phase change material away from the energy storage chamber and close to the first flow path; a heating source, the heating source is located in the heat-uniforming area and close to the side away from the rotation center.

[0013] Further, the heat-uniforming area and the slow-heating area 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 area on the switching pipeline is to the end sealing point, the farther its distance from the switching pipeline is.

[0014] Further, the length of the slow-heating area is 2-4 times the diameter of the switching pipeline, and the projection of the end of the slow-heating area away from the heat-uniforming area on the heat exchange pipeline completely covers the end sealing point; the included angle α between the heat-uniforming area and the slow-heating area is related to the diameter D of the switching pipeline,

[0015] ;

[0016] where is the reference diameter, and the value range is 0.5-1.0mm, 。

[0017] Furthermore, the soaking zone and the slow heating zone are made of an integral copper plate. The soaking zone and the slow heating zone are located on the same plane. The slow heating zone includes heat conduction parts arranged on both sides of the end of the soaking zone near the end sealing point. The width of the heat conduction part becomes narrower as it gets closer to the end sealing point. The heat conduction parts are located on both sides of the switching pipeline. The inner edges of the heat conduction parts on both sides are open and face the proximal end.

[0018] Furthermore, the first flow channel and the second flow channel are located on the same side of the switching pipeline.

[0019] Furthermore, the switching pipeline includes a first switching pipeline and a second switching pipeline. The first switching pipeline extends radially along the rotation center, and its upper end is connected to the purification module and its lower end is connected to the second switching pipeline. A first flow channel is arranged above the interface between the first switching pipeline and the second switching pipeline. The opening of the first flow channel is arranged to communicate with the side wall of the first switching pipeline. Compared with the interface between the first switching pipeline and the second switching pipeline, the opening is closer to the rotation center radially along the rotation center.

[0020] The present invention provides a centrifugal microfluidic nucleic acid detection chip, which has the following beneficial technical effects compared with the prior art:

[0021] (1) For the centrifugal microfluidic nucleic acid detection chip provided by the present invention, at least two valve groups are controlled by controlling two conditions of centrifugal force and heating, eliminating manual operation, reducing labor intensity and the possibility of operation errors. Secondly, at least two valve groups achieve at least three working states, improving the application scenarios of the product. The application scenarios include: (1) When the purification module is working normally, the purification module is not connected to the liquid control cavity (at this time, the purification module, the liquid control cavity and the reaction cavity are not connected either), ensuring the normal operation of the purification module; (2) Waste liquid is discharged, and at this time the purification module is connected to the liquid control cavity; (3) The nucleic acid after cleaning is transported to the reaction pool, and at this time the purification module, the liquid control cavity and the reaction cavity are connected; (4) During the reaction process, the purification module, the liquid control cavity and the reaction cavity are not connected, and the reaction environment is sealed to prevent inaccurate detection results caused by environmental pollution of the reaction.

[0022] (2) High reliability. The fluid structure of the chip is simple. Except for the chip body, there are no other redundant moving and mating parts. Secondly, low cost. The chip has few structural parts and low cost. The fluid structure of the chip is simple and the manufacturing cost is low. The chip has low requirements for supporting instruments, and the instrument structure is simple and the cost is low. Finally, miniaturization is achieved. The circumferential arrangement of the liquid control cavity can minimize the size of the liquid control cavity occupying the radial direction of the chip radius, thereby reducing the chip area. The design of the flow control pipeline can not only achieve the sorting of liquids, but also achieve the sealing of multiple chambers, reducing the fluid structure design, thereby achieving the miniaturization of the chip. Description of the Drawings

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 Structural diagram of a centrifugal microfluidic nucleic acid detection chip provided by an embodiment of the present invention;

[0025] Figure 2 Schematic structural diagram of a purification module provided by an embodiment of the present invention;

[0026] Figure 3 Specific structure of a pipeline switching part provided by an embodiment of the present invention;

[0027] Figure 4 Schematic structural diagram of a heating part provided by an embodiment of the present invention;

[0028] Figure 5 For Figure 4 A - A cross-sectional view of;

[0029] Figure 6 Another schematic structural diagram of a heating part provided by an embodiment of the present invention;

[0030] Figure 7 Another schematic principle diagram of a heating part provided by an embodiment of the present invention;

[0031] Figure 8 Another structural diagram of a centrifugal microfluidic nucleic acid detection chip provided by an embodiment of the present invention;

[0032] Figure 9 Enlarged partial view of a switching pipeline provided by an embodiment of the present invention;

[0033] Figure 10 First working state of a pipeline switching part provided by an embodiment of the present invention;

[0034] Figure 11 Second working state of a pipeline switching part provided by an embodiment of the present invention;

[0035] Figure 12 Third working state of a pipeline switching part provided by an embodiment of the present invention;

[0036] Figure 13 Fourth working state of a pipeline switching part provided by an embodiment of the present invention.

[0037] Reference 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 cavity; 2310, piston; 232, phase change material; 2321, liquid material; 2320, solid material; 233, end sealing point; 234, connecting pipeline; 30, heat conducting copper plate; 300, slow heat area; 3000, inner edge of heat conducting part; 301, heat equalizing area; 40, gas exchange chamber. Detailed implementation manners

[0038] To make the objectives, 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 with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. The components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0039] 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 claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0040] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0041] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0042] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and defined, the terms "arrangement", "installation", "connection", and "coupling" 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 an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] An embodiment of the present invention discloses a centrifugal microfluidic nucleic acid detection chip, as Figure 1 shown, including: a chip body 1; a biochemical reaction module 2, where the biochemical reaction module 2 is at least one, and the biochemical reaction module 2 is arranged on the chip body 1; the biochemical reaction module 2 includes a purification module 20, a liquid control cavity 21, a reaction cavity 22, and a flow path switching part 23 that are arranged downstream of the purification module 20 and away from the rotation center; the liquid control cavity 21 is communicated with the flow path switching part 23 through a first flow path 210, and the middle part of the first flow path 210 is bent towards the rotation center O direction; the reaction cavity 22 is communicated with the flow path switching part 23 through a second flow path 220, and the middle part of the second flow path 220 is bent towards the rotation center O direction; the closest distance between the first flow path 210 and the rotation center O is less than the closest distance between the second flow path 220 and the rotation center O; under the conditions of changing centrifugal force and heating, the flow path switching part 23 can repeatedly and selectively connect the purification module 20 with the liquid control cavity 21 or connect the purification module 20, the liquid control cavity 21, and the reaction cavity 22.

[0044] Specifically, the liquid control cavity 21 can be any one of the steps required for the biochemical reaction, and is used for the transfer or reaction of the liquid. In the embodiment of the present invention, the liquid control cavity 21 is a chamber for collecting waste liquid. The purification module 20 is used for the purification of nucleic acids, and the nucleic acids are washed with a washing solution, and the washed waste liquid is discharged into the liquid control cavity 21. The reaction cavity 22 is a functional cavity in the biochemical reaction module 2, and corresponding reagents or magnetic beads for accelerating the reaction can be arranged inside according to the selection of functions.

[0045] The centrifugal microfluidic nucleic acid detection chip provided by the present invention, firstly, realizes the automatic control of at least two valve groups by controlling two conditions of centrifugal force and heating, eliminating manual operation, reducing labor intensity and the possibility of operation errors; secondly, realizes three valve functions: a. realizes the mutual sealing and isolation of each chamber; b. realizes the selective connection of each chamber; c. realizes the repeated switching function; in addition, at least two valve groups realize at least three working states, improving the application scenarios of the product. The application scenarios include: (1) when the purification module 20 is working 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) discharging waste liquid, at this time the purification module 20 is connected to the liquid control chamber 21; (3) delivering the nucleic acid after washing 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, and the reaction environment is sealed to prevent inaccurate detection results caused by environmental pollution of the reaction.

[0046] Specifically, as Figure 2 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 the circumferential direction with the rotation center O as the center of the circle, 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, which is respectively connected to the sample chamber 202, the cleaning chamber 200 and the elution chamber 201, 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, so as to prevent some nucleic acid substances from adhering to the flow channel.

[0047] The cleaning chamber 200, the elution chamber 201, the sample chamber 202, the buffer chamber 203 and the nucleic acid extraction chamber 204 are respectively functional chambers. The cleaning chamber 200 stores cleaning liquid, the elution chamber 201 stores elution liquid, a sample adding hole is arranged on the sample chamber 202, and the sample to be detected is added into the sample chamber 202 through the sample adding hole. The nucleic acid extraction chamber 204 has materials for adsorbing nucleic acid inside, such as porous biopolymer adsorption materials. The porous biopolymer adsorption materials are: silica fiber or particles or loose film, ion exchange resin, silica nanoparticles, magnetic particle materials with silica on the surface, porous materials coated with silica nanoparticles on the surface, porous materials coated with chitosan on the surface, or other various porous materials with silanol modification on the surface.

[0048] The shape of the above-mentioned porous biomacromolecule adsorption material is a loose film shape, a sheet shape or a granular shape. Among them, the loose film can be a single-layer film or a multi-layer film, and can include sheets of different sizes or particles of different particle sizes; the fluid cavity can be filled with the same kind of porous biomacromolecule adsorption material, or can be filled with different kinds of porous biomacromolecule adsorption materials.

[0049] The far center end of the nucleic acid extraction cavity 204 has a contraction structure, which can be but is 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 has a rhombus structure.

[0050] It should be noted that the closest distance of the first flow channel 210 from the rotation center is less than the closest distance of the second flow channel 220 from the rotation center. As Figure 2 shown, the closest distance of the first flow channel 210 from the rotation center O is S1, and the closest distance of the second flow channel 220 from the rotation center O is S2, S1 < S2. Through the above settings, when the purification module 20, the liquid control cavity 21 and the reaction cavity 22 are connected, it is ensured that after the washed nucleic acid flows out of the purification module 20, it flows into the reaction cavity 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 control of the subsequent rotation speed.

[0051] In the embodiment of the present invention, six reaction cavities 22 are provided, and the number of reaction cavities 22 can be reduced or increased based on the test requirements.

[0052] Specifically, as Figure 3 shown, the flow channel switching part 23 includes: a switching pipeline 230, the switching pipeline 230 is gradually away from the rotation center O, the proximal end of the switching pipeline 230 is connected to the purification module 20, and a phase change material 232 is arranged in the switching pipeline 230, and the phase change material 232 becomes liquid after being heated; an energy storage chamber 231, the distal end of the switching pipeline 230 is connected to the energy storage chamber 231.

[0053] In the present invention, the energy storage chamber 231 is an energy storage structure. Its function is that when the phase change material 232 changes into a liquid state after being heated, it can be extruded by the centrifugal force to form potential energy. When the rotation speed of the microfluidic detection chip decreases, the potential energy of the energy storage chamber 231 is released to push the liquid phase change material 232 to move towards the direction close to the rotation center O. It should be noted 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 situation shown by the phase change material 232 in

[0054] Specifically, as Figure 3As shown in the figure, the energy storage chamber 231 includes an energy storage cavity 2311 and a piston 2310 that can be slidably and sealedly connected to the energy storage cavity 2311. Under the action of centrifugal force, the liquid phase change material 232 presses the piston 2310, thereby compressing the sealed space formed by the energy storage cavity 2311 and the piston 2310 to form potential energy.

[0055] In another embodiment, as Figure 2 shown, the flow path switching portion 23 further includes a bent connecting pipe 234. One end of the connecting pipe 234 communicates with the distal end of the switching pipe 230, and the other end of the connecting pipe 234 is connected to the side of the energy storage chamber 231 away from the rotation center O. At this time, 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, forms a sealed cavity with the energy storage chamber 231, and compresses the energy storage chamber 231 under the action of centrifugal force to store energy.

[0056] The phase change material 232 in the present invention can be wax. For example, the wax can be paraffin wax, 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. The thermoplastic resin can be cyclic olefin copolymer (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 polyvinylidene fluoride (PVDF), etc.

[0057] The above solution can be used for the detection of biological information, but there is still room for optimization. For example, when the first flow path 210 and the switching pipe 230 are opened, the purification module 20 is connected to the liquid control chamber 21 at this time. Under the action of centrifugal force, there is a possibility that part of the waste liquid rushes into the liquid phase change material 232 under the action of centrifugal force, so that the liquid phase change material 232 is contaminated. When the purified nucleic acid flows through the switching pipe 230 and the second flow path 220 and flows 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 is contaminated. In order to further improve the accuracy of the detection result, the present invention also proposes the following solution.

[0058] Specifically, different heating conditions are set for different parts of the flow path switching portion 23. The phase change material 232 near the first flow path 210 is slowly heated to prevent its viscosity from being too low, so that the waste liquid is easy to rush into the phase change material 232, and the other areas are evenly heated to facilitate flow.

[0059] Specifically, as Figure 4 shown, the heating part includes: a heat-conducting copper plate 30, the heat-conducting copper plate 30 has a slow-heating area 300 and a heat-uniforming area 301, the slow-heating area 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 heat-uniforming area 301 and close to the side away from the rotation center. The slow-heating area 300 heats slowly, so the viscosity of the phase-change material 232 at this place is relatively large, and the waste liquid is difficult to flush into the liquid phase-change material 232, preventing the pollution of the phase-change material 232.

[0060] As Figure 5 shown, the heat-uniforming area 301 and the slow-heating area 300 are made of an integral copper plate and are located below the phase-change material 232; the projection of the copper plate in the slow-heating area 300 on the switching pipeline 230 is closer to the end-sealing point 233, and the distance from it to the switching pipeline 230 is farther. The end-sealing point 233 is the end point of the phase-change material 232 in the switching pipeline 230. Since the closer to the end-sealing point 233, the farther the copper plate is from the phase-change material 232, the heating ability of the phase-change material 232 corresponding to the slow-heating area 300 will be weakened, and the viscosity of the phase-change material 232 corresponding to the slow-heating area 300 is relatively large, and the waste liquid is less likely to pollute the phase-change material.

[0061] As Figure 5 shown, the length L of the slow-heating area 300 is 2-4 times the diameter of the switching pipeline 230, and the projection of the end of the slow-heating area 300 away from the heat-uniforming area 301 on the heat exchange pipeline completely covers the end-sealing point 233; the included angle α between the heat-uniforming area 301 and the slow-heating area 300 is related to the diameter D of the switching pipeline 230,

[0062] ;

[0063] wherein is the reference diameter, and the value range is 0.5-1.0mm, .

[0064] It should be noted that when the cross-section of the switching pipeline 230 is not circular, the equivalent diameter can be calculated through its cross-sectional area.

[0065] Another preferred embodiment of the present invention, as Figure 6As shown, the soaking zone 301 and the slow-heating zone 300 are made of an integral copper plate. The soaking zone 301 and the slow-heating zone 300 are located on the same plane. The slow-heating zone 300 includes heat-conducting parts arranged on both sides of the end of the soaking zone 301 near the end sealing point 233. The closer the heat-conducting part is to the end sealing point 233, the narrower its width. The heat-conducting parts are located on both sides of the switching pipeline 230. The inner edges 3000 of the heat-conducting parts on both sides are in an open shape and face the proximal end. Through the above settings, slow heating of the phase change material 232 in the slow-heating zone 300 is ensured. On the other hand, the inner edges 3000 of the heat-conducting parts on both sides are in an open shape and face the proximal end. On the one hand, the flow rate of the liquid phase change material 232 is increased. On the other hand, the existence of a part of the solid state is ensured, so that the waste liquid cannot contaminate the paraffin wax.

[0066] The principle is as Figure 7 As shown, since the inner edges 3000 of the heat-conducting parts on both sides are in an open shape and face the proximal end, part of the phase change material 232 is in a solid phase, that is, the liquid material 2321 and the solid material 2320. And the inner edges 3000 of the heat-conducting parts being in an open shape makes the lower part of the solid material 2320 in a "V" shape. Since the contact area between the two sides of the solid material 2320 and the switching pipeline 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.

[0067] In another preferred embodiment, as Figure 8 shown, the first flow channel 210 and the second flow channel 220 are located on the same side of the switching pipeline 230. The size of the biochemical reaction module 2 is further reduced, so that more biochemical reaction modules 2 can be carried on the chip body 1.

[0068] When the purification module 20, the liquid control cavity 21 and the reaction cavity 22 are connected, if the rotation speed is not appropriate, there is a possibility that the purified nucleic acid enters the liquid control cavity 21. To prevent the above problems, as Figure 9 shown, the switching pipeline 230 includes a first switching pipeline 2300 and a second switching pipeline 2301. The first switching pipeline 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 pipeline 2301. A first flow channel 210 is arranged above the interface 2302 between the first switching pipeline 2300 and the second switching pipeline 2301. The opening of the first flow channel 210 is communicated with the side wall of the first switching pipeline 2300. Compared with the interface 2302 between the first switching pipeline 2300 and the second switching pipeline 2301, the opening is closer to the rotation center along the radial direction of the rotation center.

[0069] The nucleic acid detection chip proposed by the present invention is also provided with a gas exchange system, as Figure 1As shown, the gas exchange system includes a gas exchange chamber 40, which is divided into two connected parts, located between the cleaning chamber 200 and the sample chamber 202, and between the elution chamber 201 and the sample chamber 202 respectively. 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.

[0070] The working principle of the above centrifugal microfluidic nucleic acid detection chip is as follows: As Figure 10 shown, before the experiment starts, a phase change material 232 (black) is arranged in the switching pipeline 230 of the flow path switching part 23, realizing the sealing of the purification module 20, the liquid control chamber 21 and the reaction chamber 22. After the experiment starts, heating is started, the phase change material 232 in the switching pipeline 230 melts (becomes gray), centrifugation is started, a centrifugal speed V1 is applied, and the melted phase change material 232 in the switching pipeline 230 enters the energy storage chamber 231 under the action of centrifugal force, and squeezes the space in the energy storage chamber 231. As Figure 11 shown, the first flow path 210 connecting 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 path 210. When the liquid in the purification module 20 is completely centrifuged into the liquid control chamber 21, centrifugation is stopped, and the compressed gas in the energy storage chamber 231 pushes out the melted liquid phase change material 232, closing the first flow path 210 again, and realizing sealing again after cooling. As Figure 12 shown. Similarly, heating is started again, the phase change material 232 in the flow control pipeline is melted, a centrifugal speed V2 is applied, and the melted phase change material 232 enters the energy storage chamber 231 again under the action of centrifugal force. The first flow path 210 connecting the liquid control chamber 21 and the second flow path 220 connecting the reaction chamber 22 are opened. Since the liquid outlet of the second flow path 220 is farther from the rotation center than the liquid outlet of the first flow path 210, and the highest point of the second flow path 220 is farther from the rotation center than the highest point of the first flow path 210, the liquid in the purification module 20 enters the reaction chamber 22 through the second flow path 220. As Figure 13 shown. When the liquid in the purification module 20 is completely transferred to the reaction chamber 22, centrifugation is stopped, and the compressed gas in the energy storage chamber 231 pushes out the melted liquid phase change material 232, closing the first flow path 210 and the second flow path 220 again, and realizing sealing again after cooling. As Figure 12 shown.

[0071] It should be noted that in the above working principle, melting is carried out first and then centrifugation operation is performed. It is also possible to adopt centrifugation operation first, and heating is carried out during the centrifugation process. In this way, without all the phase change material 232 being melted, the corresponding flow paths can also be connected under the action of centrifugal force. And based on the heating part proposed in this application, the effect of heating during centrifugation is better.

[0072] The specific experimental procedure is as follows:

[0073] 1. Add a nucleic acid sample into the sample chamber 202 through the sample inlet.

[0074] 2. Start centrifugation at 2000 rpm. The sample enters the nucleic acid extraction chamber 204 through the buffer chamber 203, and the nucleic acid sample is fully mixed with the magnetic beads pre-stored in the nucleic acid extraction chamber 204. After the magnetic beads complete nucleic acid adsorption, stop centrifugation.

[0075] 3. Start heating to melt the phase change material 232 in the switching pipeline 230, and at the same time start centrifugation at 2200 rpm. The melted phase change material 232 in the flow control pipeline enters the energy storage chamber 231 under the action of centrifugal force. 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 down. The phase change material 232 re-completes the sealing between the nucleic acid extraction chamber 204 and the liquid control chamber 21.

[0076] 4. Start centrifugation at 2600 rpm again. 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 centrifugation.

[0077] 5. Repeat step 3. The waste liquid after magnetic bead cleaning enters the liquid control chamber 21, then stop centrifugation and cool down. The phase change material 232 re-completes the sealing between the nucleic acid extraction chamber 204 and the liquid control chamber 21.

[0078] 6. Start centrifugation at 3200 rpm again. The liquid in the elution chamber 201 enters the nucleic acid extraction chamber 204 through the buffer chamber 203. After the eluent elutes the nucleic acid adsorbed on the surface of the magnetic beads in the nucleic acid extraction chamber 204, stop centrifugation.

[0079] 7. Start heating to melt the phase change material 232 in the switching pipeline 230 again, and at the same time start centrifugation at 3000 rpm. The melted phase change material 232 in the flow control pipeline enters the energy storage chamber 231 more under the action of centrifugal force. The pipelines between the nucleic acid extraction chamber 204 and the liquid control chamber 21 and the reaction chamber 22 are connected simultaneously. However, since the outlet pipe inlet connected to the reaction chamber 22 is farther from the rotation center than the outlet pipe inlet connected to the liquid control chamber 21, the nucleic acid eluate enters each reaction chamber 22 under the action of centrifugal force. Then stop centrifugation and cool down. The phase change material 232 re-completes the sealing of the nucleic acid extraction chamber 204, the liquid control chamber 21 and the reaction chamber 22.

[0080] 8. Perform nucleic acid amplification and collect the real-time fluorescence curve.

[0081] The above are only embodiments of the present application and are not intended to limit the protection scope of the present application. For those skilled in the art, various modifications and changes can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope 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; 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.

2. The centrifugal microfluidic nucleic acid detection chip according to claim 1, 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.

3. The centrifugal microfluidic nucleic acid detection chip according to claim 1 or 2, characterized in that: Different heating conditions are set for different parts of the flow channel switching part.

4. The centrifugal microfluidic nucleic acid detection chip according to claim 3, 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.

5. The centrifugal microfluidic nucleic acid detection chip according to claim 4, 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.

6. The centrifugal microfluidic nucleic acid detection chip according to claim 5, 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 heat-averaging zone on the switching 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. Where D0 is the reference diameter, the value range is 0.5-1.0mm, D0<D<2D0.

7. The centrifugal microfluidic nucleic acid detection chip according to claim 4, 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.

8. The centrifugal microfluidic nucleic acid detection chip according to claim 1, characterized in that: The first flow channel and the second flow channel are located on the same side of the switching pipe.

9. The centrifugal microfluidic nucleic acid detection chip according to claim 1, 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 of the first flow channel is closer to the rotation center along the radial direction of the rotation center.

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