Excrement nucleic acid extraction card box and nucleic acid extraction method using same

Abstract

The invention provides an excrement nucleic acid extraction card box and a nucleic acid extraction method using the same, the excrement nucleic acid extraction card box comprises a card box main body, a sample hole, a waste liquid bin, a binding liquid bin, a magnetic bead reaction bin, a first washing liquid bin, an eluent bin and an amplification bin are constructed on the top surface of the card box main body, and the sample hole is used for positioning and accommodating an excrement pretreatment pipe; the excrement pretreatment pipe is provided with an outer pipe body, an inner pipe body and a sealing cover, the inner pipe body can be inserted into the outer pipe body through a top pipe opening, a filtering structure is formed at the pipe bottom of the inner pipe body, and in the process that the inner pipe body is inserted into the outer pipe body, the filtering structure is sealed. The filtering structure can form solid-liquid separation on the excrement sample liquid contained in the outer tube body, so that supernate of the excrement sample liquid is located in the inner tube body. According to the invention, the automatic treatment of the fecal nucleic acid can be realized without greatly improving the structure of the existing nucleic acid extraction equipment, the dependence degree of fecal nucleic acid extraction on manual intervention is reduced, and the clinical high-throughput detection requirement is met.

Description

Technical Field

[0001] The present invention belongs to the technical field of nucleic acid extraction from biological samples, and particularly relates to a fecal nucleic acid extraction cartridge and a nucleic acid extraction method using the same. Background Art

[0002] As the core carrier of gastrointestinal pathogens, tumor markers and intestinal flora, fecal samples have irreplaceable value in clinical diagnosis and research. Although nucleic acid amplification testing technologies (NAATs) have been proven to have great clinical value in the application of fecal samples, their practical application is limited by the characteristics of high-concentration inhibitors (bile salts, phenols, lipids, etc.) and high viscosity in feces.

[0003] Existing automated nucleic acid extraction devices are mostly designed for homogeneous liquid samples such as blood and saliva, and their standardized processes cannot adapt to the complex matrix of fecal samples: 1) The precipitation of inhibitors relies on manual centrifugation (on average ≥2 times of opening the lid to transfer liquid), and the discrete operation causes psychological discomfort of operators and doubles the risk of aerosol contamination; 2) The adsorption efficiency of the traditional magnetic bead method drops sharply in viscous samples, and manual vortex mixing is required; 3) There are mechanical compatibility obstacles between the centrifugal device and the automated platform, and full-process automated processing cannot be achieved. The above technical defects result in that fecal nucleic acid extraction still heavily relies on manual intervention and is difficult to meet the requirements of clinical high-throughput detection. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a fecal nucleic acid extraction cartridge and a nucleic acid extraction method using the same, so as to solve the technical problem that in the prior art, a centrifugal separation device is required to achieve solid-liquid separation of the sample liquid during fecal nucleic acid extraction, making it difficult to be compatible with existing automated platforms (such as nucleic acid automated extractors), unable to achieve full-process automated processing of fecal nucleic acid extraction, resulting in that fecal nucleic acid extraction heavily relies on manual intervention and is difficult to meet the requirements of clinical high-throughput detection.

[0005] To solve the above problems, the present invention provides a fecal nucleic acid extraction cartridge, including a cartridge main body. On the top surface of the cartridge main body, a sample hole, a waste liquid chamber, a binding liquid chamber, a magnetic bead reaction chamber, a first washing liquid chamber, an elution liquid chamber, and an amplification chamber are constructed. The sample hole is used to position and accommodate a fecal pretreatment tube. The fecal pretreatment tube has an outer tube body, an inner tube body, and a sealing cap that can be detachably and sealingly connected to the top pipe orifice of the outer tube body. The inner tube body can be inserted into the outer tube body through the top pipe orifice. A filtering structure is formed at the bottom of the inner tube body, and when the inner tube body is inserted into the outer tube body, the filtering structure can perform solid-liquid separation on the fecal sample liquid contained in the outer tube body so that the supernatant of the fecal sample liquid is inside the inner tube body.

[0006] In some embodiments, a mineral oil reservoir is further formed on the top surface of the cartridge body; and / or, a second washing liquid reservoir is further formed on the top surface of the cartridge body; and / or, there are at least two amplification chambers.

[0007] In some embodiments, the bottom wall of the magnetic bead reaction chamber has an arc portion, and the arc portion can form a downward vortex when the pipette blows on the bottom wall of the magnetic bead reaction chamber.

[0008] In some embodiments, a bottom wall plate with a first through hole is formed on the bottom of the inner tube body, and a fixing pad with a second through hole connected to the outside of the bottom wall plate is provided. A filter membrane is clamped between the bottom wall plate and the fixing pad to form the filtering structure.

[0009] In some embodiments, the tube side wall of the inner tube body has an annular wall protruding outside the bottom wall plate. A plurality of protrusions are arranged around the tube center line of the inner tube body inside the annular wall, and the fixing pad is axially limited on the side of each protrusion facing the bottom wall plate.

[0010] In some embodiments, an annular groove is formed on the tube side wall around the tube center line of the inner tube body, and a sealing ring is clamped between the annular groove and the inner wall of the outer tube body.

[0011] In some embodiments, two buckles symmetrical about the tube center line of the outer tube body are provided on the outer surface of the tube side wall of the outer tube body, and two clamping grooves corresponding to the buckles one by one are formed on the inner wall of the orifice of the sample hole; and / or, the supporting part of the cartridge body is made of an anti-seismic and buffer material.

[0012] The present invention also provides a nucleic acid extraction method using the above-mentioned fecal nucleic acid extraction cartridge, including the following steps:

[0013] Fecal sample pretreatment step: Load the fecal sample into the outer tube body containing the sample pretreatment liquid and the crushing beads, seal the top orifice of the outer tube body with the sealing cover, and perform pretreatment on the fecal sample;

[0014] Pretreatment tube transfer step: Position and place the pretreated outer tube body in the sample hole of the fecal nucleic acid extraction cartridge, and place the fecal nucleic acid extraction cartridge into the fully automatic nucleic acid extraction detector;

[0015] Fully automatic nucleic acid extraction step: After controlling the robotic arm of the fully automatic nucleic acid extraction detector to remove the sealing cover sealed to the top orifice of the outer tube body, control the robotic arm to insert the inner tube body into the outer tube body from the top orifice of the outer tube body to achieve solid-liquid separation, and the sample supernatant is in the inner tube body;

[0016] Control the pipette to aspirate a preset amount of supernatant into the magnetic bead reaction chamber to achieve the binding of nucleic acid to the surface of the magnetic beads, and after completing the operations of magnetic bead washing and nucleic acid elution, transfer the eluted nucleic acid into the amplification chamber.

[0017] In some embodiments, in the fecal sample pretreatment step, the pretreatment of the fecal sample includes:

[0018] Manually mix the fecal sample contained in the outer tube body with the pretreatment solution to form a homogenate, and then place it on a metal bath or a shaking heater and heat it to a preset temperature.

[0019] In some embodiments, after the pipette aspirates a preset amount of supernatant into the magnetic bead reaction chamber, aspirate a preset amount of binding solution from the binding solution chamber into the magnetic bead reaction chamber to terminate the aluminum salt reaction and reduce the solubility of nucleic acid at the same time.

[0020] A fecal nucleic acid extraction cartridge provided by the present invention and a nucleic acid extraction method using the same form all the reagents related to fecal nucleic acid extraction on the cartridge body, enabling a physical structure basis for fully automated processing of fecal nucleic acid extraction. At the same time, the filtering structure at the bottom of the inner tube body of the fecal pretreatment tube can form solid-liquid separation of the solid-liquid mixed sample placed in the outer tube body during the process of inserting the inner tube body into the outer tube body, so that the supernatant of the fecal sample liquid is filtered and located in the inner tube body. In this way, the nucleic acid extraction device (i.e., the automated platform, such as a nucleic acid extraction detector) does not need to specifically configure a corresponding centrifugal device for the separation of the supernatant of the fecal sample liquid, that is, it can use the existing nucleic acid extraction device to achieve the automated processing of fecal nucleic acid without major structural improvements to the existing nucleic acid extraction device, reducing the dependence on manual intervention in fecal nucleic acid extraction and meeting the clinical high-throughput detection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic perspective view (appearance) of the fecal nucleic acid extraction cartridge according to an embodiment of the present invention;

[0022] Figure 2 is Figure 1 a longitudinal sectional view of the fecal nucleic acid extraction cartridge in

[0023] Figure 3 is Figure 1 a structural exploded view (three-dimensional) of the fecal pretreatment tube in

[0024] The reference numerals are shown as:

[0025] 1. Cartridge body; 11. Sample hole; 111. Card slot; 12. Waste liquid chamber; 13. Binding liquid chamber; 14. Magnetic bead reaction chamber; 151. First washing liquid chamber; 152. Second washing liquid chamber; 16. Elution liquid chamber; 17. Amplification chamber; 18. Mineral oil chamber; 2. Fecal pretreatment tube; 21. Outer tube body; 211. Buckle; 22. Inner tube body; 221. Bottom wall plate; 222. Fixed backing plate; 223. Protrusion; 224. Annular groove; 23. Sealing cover. Detailed implementation manner

[0026] With reference to Figures 1 to 3 As shown, according to an embodiment of the present invention, a fecal nucleic acid extraction cartridge is provided, including a cartridge body 1. On the top surface of the cartridge body 1, a sample hole 11, a waste liquid chamber 12 for storing waste liquid generated during the nucleic acid providing process, a binding liquid chamber 13 for storing binding liquid, a magnetic bead reaction chamber 14 for storing magnetic beads and performing magnetic bead adsorption, a first washing liquid chamber 151 for storing the first washing liquid, an elution liquid chamber 16 for storing elution liquid, and an amplification chamber 17 for performing nucleic acid amplification are constructed. The sample hole 11, the waste liquid chamber 12, the binding liquid chamber 13, the magnetic bead reaction chamber 14, the first washing liquid chamber 151, the elution liquid chamber 16, and the amplification chamber 17 are arranged in a substantially straight line along the longitudinal direction of the cartridge body 1 (specifically forming a boat-shaped cartridge structure). The sample hole 11 is used to position and accommodate the fecal pretreatment tube 2. Specifically, with reference to Figure 3 As shown, the fecal pretreatment tube 2 has an outer tube body 21, an inner tube body 22, and a sealing cover 23 that can be detachably and sealingly connected to the top pipe orifice of the outer tube body 21. The inner tube body 22 can be inserted into the outer tube body 21 through the top pipe orifice. A filtering structure (not labeled in the figure) is formed at the bottom of the inner tube body 22. And when the inner tube body 22 is inserted (along the coaxial axis direction of the two tube bodies) into the outer tube body 21, the filtering structure can perform solid-liquid separation on the fecal sample liquid contained in the outer tube body 21 so that the supernatant of the fecal sample liquid is inside the inner tube body 22.

[0027] In this technical solution, all reagents related to fecal nucleic acid extraction are formed on the cartridge body 1, so that the fecal nucleic acid extraction can have a physical structural basis for fully automated processing. At the same time, the filtering structure at the bottom of the inner tube body 22 of the fecal pretreatment tube 2 can separate the solid-liquid mixed sample contained in the outer tube body 21 during the process of the inner tube body 22 being inserted into the outer tube body 21, so that the supernatant of the fecal sample liquid is filtered and placed in the inner tube body 22. In this way, the nucleic acid extraction equipment (that is, the automated platform, such as the nucleic acid extraction detector) does not need to be specially configured with a corresponding centrifugal device for supernatant separation of the fecal sample liquid, that is, there is no need to make major structural improvements to the existing nucleic acid extraction equipment to achieve automated processing of fecal nucleic acid, reduce the degree of dependence of fecal nucleic acid extraction on manual intervention, and meet the clinical high-throughput detection needs.

[0028] In some embodiments, a mineral oil tank 18 is formed on the top surface of the cartridge body 1 for pre-storing mineral oil such as paraffin, so as to form an oil seal on the amplification sample liquid surface when amplifying nucleic acid to prevent evaporation and loss of the sample liquid. In a preferred embodiment, a second washing liquid tank 152 is also formed on the top surface of the cartridge body 1.

[0029] In order to achieve the purpose of detecting more targets simultaneously, the amplification chambers 17 have at least two.

[0030] See Figure 2 As shown, in some embodiments, the bottom wall of the magnetic bead reaction chamber 14 has an arc-shaped portion (not marked in the figure), and the arc-shaped portion can form a top-down vortex when the pipette (the structure configured in the nucleic acid extraction device) blows the bottom wall of the magnetic bead reaction chamber 14 to ensure that the magnetic beads are fully mixed. It can be understood that the arc-shaped bottom wall of the magnetic bead reaction chamber 14 also provides the required space for the magnetic collection step. In specific applications, the nucleic acid extraction device is also configured with a magnetic separation module (not shown in the figure), which includes a movable electromagnet device that can control the magnetic field strength and position according to the program to achieve accurate capture and release of magnetic beads, ensuring efficient recovery of nucleic acids during the extraction process.

[0031] See Figure 3As shown, in some embodiments, a bottom wall plate 221 having a first through hole (not labeled in the figure) is formed on the bottom of the inner tube body 22, and a fixing backing plate 222 having a second through hole (not labeled in the figure) is connected to the outside of the bottom wall plate 221. A filter membrane (not labeled in the figure) is clamped between the bottom wall plate 221 and the fixing backing plate 222 to form the filtering structure. Specifically, the filter membrane can be a filter screen, a filter membrane or a filter paper with a suitable mesh number according to actual requirements. In some specific embodiments, the filter membrane adopts a coarse filtering material (such as polypropylene non-woven fabric with a pore size of 10 μm) and a fine filtering material (polyethersulfone filter membrane with a pore size of 0.45 μm). When the inner tube body 22 and the outer tube body 21 are in an assembled state, the positions of the first through holes and the second through holes correspond to each other and are penetrated, so as to ensure the flow-through area of the filter membrane and further improve the solid-liquid separation effect.

[0032] In this technical solution, by clamping the filter membrane by the bottom wall plate 221 and the fixing backing plate 222, reliable support for the filter membrane can be ensured, thereby improving the filtering effect and service life of the filter membrane.

[0033] In a specific embodiment, the sizes and shapes of the first through hole and the second through hole correspond to each other one by one.

[0034] The outer tube body 21, the inner tube body 22 and the sealing cover 23 are specifically made of corrosion-resistant materials, and the corrosion-resistant materials are, for example, one of polyurethane, polytetrafluoroethylene, polyether ether ketone and polyphenylene sulfide.

[0035] In some embodiments, the tube side wall of the inner tube body 22 has an annular wall (not labeled in the figure) protruding outside the bottom wall plate 221. A plurality of protrusions 223 are arranged around the center line of the tube body of the inner tube body 22 inside the annular wall. The fixing backing plate 222 is axially limited to the side of each protrusion 223 facing the bottom wall plate 221. The axial direction of the fixing backing plate 222 is reliably limited by the plurality of protrusions 223, thereby ensuring reliable support of the fixing backing plate 222 for the filter membrane. In a specific embodiment, the number of the protrusions 223 is three.

[0036] In some embodiments, an annular groove 224 is formed on the tube side wall and arranged around the center line of the tube body of the inner tube body 22. A sealing ring (not shown and not labeled in the figure) is clamped between the annular groove 224 and the inner wall of the outer tube body 21. In a specific embodiment, the wire diameter of the sealing ring is 0.5 mm to 0.8 mm, and the inner diameter is 6 - 10 mm.

[0037] In this technical solution, an annular groove 224 with a trapezoidal cross-section is provided on the pipe side wall of the inner pipe body 22, so that the sealing ring can be reliably clamped in the gap between the inner pipe body 22 and the outer pipe body 21. During the process of inserting the inner pipe body 22 into the outer pipe body 21, it can ensure that the sample liquid can be sealed between the inner pipe body 22 and the outer pipe body 21 and the supernatant is filtered by the filter membrane to achieve solid-liquid separation, improving the separation effect and efficiency.

[0038] In a specific embodiment set, the volume of the outer pipe body 21 is ~7.0 mL (height-diameter ratio 2 - 7), and the volume of the inner pipe body 22 is ~5.5 mL (height-diameter ratio 2 - 7). The central diameters of the first through hole and the second through hole are 1 mm - 5 mm, and the periphery is fan-shapedly distributed to improve the rigidity of the filter membrane limiting structure.

[0039] In some embodiments, the bottom wall of the outer pipe body 21 is an inverted cone with a larger upper part and a smaller lower part. In a specific embodiment, the apex angle of the aforementioned inverted cone is 130° - 150°. In this way, it is beneficial for the solid components after solid-liquid separation to converge at the bottom, and can further improve the solid-liquid separation efficiency.

[0040] In some embodiments, the sealing cover 23 is threadedly connected to the outer wall surface of the pipe orifice of the outer pipe body 21, facilitating the convenient assembly between the sealing cover 23 and the outer pipe body 21.

[0041] In some embodiments, two buckles 211 symmetrical about the pipe center line of the outer pipe body 21 are provided on the outer surface of the pipe side wall of the outer pipe body 21, and two clamping grooves 111 corresponding to the buckles 211 one by one are formed on the inner wall of the orifice of the sample hole 11. That is, when the outer pipe body 21 is placed in the sample hole 11, the buckles 211 are correspondingly clamped in the corresponding clamping grooves 111 one by one. In this way, a reliable limit can be formed on the circumferential rotational displacement of the outer pipe body 21, which is beneficial for the manipulator in the nucleic acid extraction device to disassemble the aforementioned sealing cover 23.

[0042] The support part of the cartridge main body 1 is prepared from an anti-seismic and buffer material (such as a foam layer, a shock-absorbing sponge layer, etc.) to reduce the influence of external vibration on reagent mixing and improve system stability. A standard interface is provided at the bottom of the cartridge main body 1, which can be seamlessly docked with the track or platform in the nucleic acid extraction device to achieve efficient loading and unloading operations.

[0043] In a specific embodiment, the hole diameter of the aforementioned sample hole 11 is 10 - 20 mm.

[0044] According to an embodiment of the present invention, there is also provided a nucleic acid extraction method using the above-mentioned fecal nucleic acid extraction cartridge, including the following steps:

[0045] Fecal sample pretreatment step: Load the fecal sample into the outer tube body 21 containing the sample pretreatment solution and the bead, seal the top nozzle of the outer tube body 21 with the sealing cap 23, and perform pretreatment on the fecal sample;

[0046] Pretreatment tube transfer step: Position and place the pretreated outer tube body 21 in the sample well 11 of the fecal nucleic acid extraction cassette, and place the fecal nucleic acid extraction cassette into the automatic nucleic acid extraction detector;

[0047] Automatic nucleic acid extraction step: After controlling the robotic arm of the automatic nucleic acid extraction detector to remove the sealing cap 23 sealed to the top nozzle of the outer tube body 21, control the robotic arm to insert the inner tube body 22 into the outer tube body 21 from the top nozzle of the outer tube body 21 to achieve solid-liquid separation, and the sample supernatant is in the inner tube body 22;

[0048] Control the pipette to aspirate a preset amount of supernatant into the magnetic bead reaction chamber 14 to achieve the binding of nucleic acid to the surface of the magnetic beads, and after completing the magnetic bead washing (using the cleaning liquid stored in the first washing liquid chamber 151 and / or the second washing liquid chamber 152) and nucleic acid elution (using the elution liquid stored in the elution liquid chamber 16) operations, transfer the eluted nucleic acid to the amplification chamber 17. When multiple targets need to be detected simultaneously, transfer it to the corresponding number of amplification chambers 17. Then, perform the corresponding amplification reaction. As a preferred method, when there is also a mineral oil chamber 18 formed on the cassette body 1, use the pipette to aspirate a fixed amount of mineral oil and drop it onto the liquid surface of the amplification chamber 17 before performing the subsequent amplification PCR reaction.

[0049] In this technical solution, after the fecal sample is pretreated in the fecal pretreatment tube 2, it is directly placed in the sample well 11 of the cassette body 1 and sent into the nucleic acid extraction device along with the fecal nucleic acid extraction cassette. The robotic arm of the nucleic acid extraction device automatically opens the sealing cap 23 and inserts the inner tube body 22 along the axial direction of the outer tube body 21 into the outer tube body 21 to achieve solid-liquid separation of the sample liquid, facilitating the acquisition of the supernatant. The opening of the sealing cap 23 is automatically performed in the nucleic acid extraction detector, eliminating the need for manual opening and centrifugation steps, reducing clinical operations, and avoiding direct contact between clinical samples and contaminating components such as feces or fecal leachate.

[0050] In some embodiments, to ensure the full progress of sample pretreatment, in the fecal sample pretreatment step, the pretreatment of the fecal sample includes: manually mixing the fecal sample contained in the outer tube body 21 with the pretreatment solution to form a homogeneous slurry and then heating it to a preset temperature (70°C in one embodiment) on a metal bath or a shaking heater.

[0051] In some embodiments, after the pipette aspirates a preset amount of supernatant into the magnetic bead reaction chamber 14, a preset amount of binding solution is aspirated from the binding solution chamber 13 into the magnetic bead reaction chamber 14 to reduce the nucleic acid solubility while terminating the aluminum salt reaction.

[0052] The following further elaborates on the nucleic acid extraction process for fecal samples in conjunction with a specific embodiment:

[0053] (1) Clinical patient sampling: 200 - 500 mg of fecal sample is loaded into a first container (i.e., the aforementioned outer tube body 21) containing 2 mL of sample pretreatment solution and 100 mL of crushing beads, the sealing cap (i.e., the aforementioned sealing cap 23) is tightened, and it is placed at -20 °C for storage or transportation.

[0054] (2) Clinical laboratory personnel: Thaw the above sample tube, place it on a vortex mixer and mix thoroughly until the feces and pretreatment solution form a homogeneous slurry; place the above sample tube on a metal bath or shaking heater and heat it at 70 °C for 5 min; then place the heated sample tube into the sample well (i.e., the aforementioned sample well 11) of the boat-shaped cartridge (i.e., the aforementioned fecal nucleic acid extraction cartridge), and then place the cartridge into the corresponding fully automatic nucleic acid detector (i.e., the aforementioned nucleic acid extraction detector) for the subsequent nucleic acid extraction process.

[0055] (3) Fully automatic instrument: The instrument uses a robotic arm to open the lid of the sample tube. After opening the lid, the lid is placed in front of the cartridge, and the solid-liquid separation tube (i.e., the aforementioned inner tube body 22) pre-placed inside the instrument is picked up and inserted into the first container containing the sample suspension to achieve solid-liquid separation. Subsequently, the instrument aspirates 600 μL of the separated supernatant into the magnetic bead reaction well. Then, the instrument aspirates 600 μL of the binding solution into the magnetic bead reaction well to terminate the aluminum salt reaction, reduce the nucleic acid solubility, and promote its binding to the magnetic bead surface at the same time. Then, the instrument heats to 90 °C through a metal bath to perform magnetic bead binding; subsequently, the instrument sequentially adds the washing solution (i.e., the aforementioned cleaning solution) to wash the magnetic beads, and finally the instrument adds the elution solution, and performs nucleic acid elution at a temperature of 55 °C. The eluted nucleic acid is completely transferred into the amplification tube for subsequent nucleic acid amplification.

[0056] In the technical solution of the present invention, the fecal pretreatment tube optimizes the fecal sample pretreatment steps, adopts a filtration-based solid-liquid separation method, effectively reduces manual operations, avoids opening the lid and liquid transfer, greatly improves the nucleic acid extraction efficiency and extraction quality, and reduces the risk of cross-contamination at the same time. The invention combines with a fully automatic nucleic acid detection instrument and can be widely applied to medical institutions, disease control centers, and scientific research laboratories, providing an efficient and automated nucleic acid extraction solution in cooperation with corresponding reagents.

[0057] Those skilled in the art can easily understand that, on the premise of no conflict, the above-mentioned advantageous ways can be freely combined and superimposed.

[0058] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and variations can be made, and these improvements and variations should also be regarded as within the protection scope of the present invention.

Claims

1. A fecal nucleic acid extraction cartridge, characterized in that, It includes a cartridge body (1), on the top surface of which a sample hole (11), a waste liquid bin (12), a binding liquid bin (13), a magnetic bead reaction bin (14), a first washing liquid bin (151), an elution liquid bin (16), and an amplification bin (17) are constructed. The sample hole (11) is used to position and accommodate a fecal sample pretreatment tube (2). The fecal sample pretreatment tube (2) has an outer tube body (21), an inner tube body (22), and a sealing cap (23) that can be detachably and sealingly connected to the top pipe orifice of the outer tube body (21). The inner tube body (22) can be inserted into the outer tube body (21) through the top pipe orifice. A filtering structure is formed at the bottom of the inner tube body (22). And during the process of inserting the inner tube body (22) into the outer tube body (21), the filtering structure can perform solid-liquid separation on the fecal sample liquid contained in the outer tube body (21) so that the supernatant of the fecal sample liquid is inside the inner tube body (22).

2. The fecal nucleic acid extraction cartridge according to claim 1, wherein A mineral oil bin (18) is also formed on the top surface of the cartridge body (1); and / or, a second washing liquid bin (152) is also formed on the top surface of the cartridge body (1); and / or, there are at least two amplification bins (17).

3. The fecal nucleic acid extraction cartridge according to claim 1, wherein The bottom wall of the magnetic bead reaction bin (14) has an arc-shaped part, and the arc-shaped part can form a downward vortex when the pipette blows on the bottom wall of the magnetic bead reaction bin (14).

4. The fecal nucleic acid extraction cartridge according to claim 1, wherein A bottom wall plate (221) with a first through hole and a fixing backing plate (222) with a second through hole connected to the outside of the bottom wall plate (221) are formed on the bottom of the inner tube body (22). A filter membrane is clamped between the bottom wall plate (221) and the fixing backing plate (222) to form the filtering structure.

5. The fecal nucleic acid extraction cartridge according to claim 4, wherein The tube side wall of the inner tube body (22) has an annular wall protruding outside the bottom wall plate (221). Inside the annular wall, there are a plurality of protrusions (223) arranged around the tube center line of the inner tube body (22). The fixing backing plate (222) is axially limited on the side of each protrusion (223) facing the bottom wall plate (221).

6. The fecal nucleic acid extraction cartridge according to claim 5, wherein An annular groove (224) arranged around the tube center line of the inner tube body (22) is formed on the tube side wall. A sealing ring is clamped between the annular groove (224) and the inner wall of the outer tube body (21).

7. The fecal nucleic acid extraction cartridge according to claim 1, wherein Two buckles (211) symmetric about the tube center line of the outer tube body (21) are provided on the outer surface of the tube side wall of the outer tube body (21). Two clamping grooves (111) corresponding to the buckles (211) one by one are formed on the inner wall of the orifice of the sample hole (11); and / or, the support part of the cartridge body (1) is prepared from an earthquake-resistant and shock-absorbing material.

8. A nucleic acid extraction method using the fecal nucleic acid extraction cartridge according to any one of claims 1 to 7, characterized in that, It includes the following steps: Fecal sample pretreatment step: Load the fecal sample into the outer tube body (21) containing the sample pretreatment liquid and the crushing beads, seal the top pipe orifice of the outer tube body (21) with the sealing cap (23), and perform pretreatment on the fecal sample; Pre-treatment tube transfer step: Position and place the pre-treated outer tube body (21) in the sample well (11) of the fecal nucleic acid extraction cartridge, and place the fecal nucleic acid extraction cartridge into the fully automatic nucleic acid extraction detector; Fully automatic nucleic acid extraction step: After controlling the robotic arm of the fully automatic nucleic acid extraction detector to remove the sealing cap (23) sealed to the top nozzle of the outer tube body (21), control the robotic arm to insert the inner tube body (22) into the outer tube body (21) from the top nozzle of the outer tube body (21) to achieve solid-liquid separation, and the sample supernatant is in the inner tube body (22); Control the pipette to aspirate a preset amount of the supernatant into the magnetic bead reaction chamber (14) to achieve the binding of nucleic acid to the surface of the magnetic beads, and after completing the magnetic bead washing and nucleic acid elution operations, transfer the eluted nucleic acid to the amplification chamber (17).

9. The nucleic acid extraction method according to claim 8, wherein In the fecal sample pre-treatment step, the pre-treatment of the fecal sample includes: Manually mix the fecal sample contained in the outer tube body (21) with the pre-treatment solution to form a homogenate, and then place it on a metal bath or a shaking heater and heat it to a preset temperature.

10. The nucleic acid extraction method according to claim 8, wherein, After the pipette aspirates a preset amount of the supernatant into the magnetic bead reaction chamber (14), aspirate a preset amount of the binding solution from the binding solution chamber (13) into the magnetic bead reaction chamber (14) to terminate the aluminum salt reaction and reduce the nucleic acid solubility at the same time.

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