A nucleic acid processing closed cartridge and method

Abstract

The present invention relates to a nucleic acid processing closed cartridge and method, including a base disposed in the cartridge, a pipette tip placement structure, a pipette tip adapter supporting at least three degrees of freedom of displacement, and at least two pipette tips, which ensure the accuracy of liquid transfer, improve the applicable range of the cartridge, and further realize the replacement operation of the pipette tip by utilizing the movement action of the pipette tip in the closed cartridge and the structure of the cartridge itself. Correspondingly, the sealing structure between the pipette tip and the pipette tip adapter is optimized to reduce the force required for the installation and detachment of the pipette tip, having the advantages of simple structure, low cost, and strong operability.

Description

Technical Field

[0001] The present invention relates to the technical field of nucleic acid detection experimental instruments, and particularly to a nucleic acid processing closed cartridge and method. Background Art

[0002] During the nucleic acid detection experiment process, a pipette with a sampling tip is required for reagent transfer operations. In the prior art (such as the invention patent with publication number CN102482696B), in order to ensure that the experimental process is not contaminated and the experimental results are accurate, various reagents used in nucleic acid detection are arranged in a relatively closed cartridge. Similarly, the reagent transfer operation also needs to be carried out in the cartridge. When switching to aspirate different reagents, usually an additional cleaning step of the sampling tip is adopted to avoid contamination of the subsequent reagent transfer process by the prior operation. However, since the experimental process involves the transfer of reagents with different volumes, using a unified sampling tip needs to take into account both large-volume and small-volume reagent transfers simultaneously, and targeted configuration cannot be achieved. Inevitably, some pipetting accuracy will be sacrificed, and it cannot meet the experimental processes with higher accuracy requirements such as nucleic acid extraction and library preparation. On the other hand, when the sampling tip is contaminated with reagents or pollutants that are difficult to clean (for example, when dewaxing nucleic acid extraction from FFPE causes some wax to adhere to the sampling tip), simply performing the cleaning step may not be able to completely remove it. Therefore, in some specific usage scenarios, the existing closed cartridges are difficult to apply.

[0003] Therefore, there is an urgent need for a closed cartridge that can provide multiple different sampling tips for replacement use to ensure the accuracy of pipetting and expand the applicable range.

[0004] In the existing pipetting and dispensing workstations for biochemical analysis or medical detection, the sampling tips are placed in a sampling tip box. The pipette moves to the corresponding sampling tip position, and by moving the Z-axis of the pipette downward, the sampling tip is installed on the sampling tip adapter of the pipette to achieve the installation of the sampling tip. The sampling tip on the pipette is pushed down by using the de-sampling tip mechanism of the pipette itself to complete the de-sampling tip action. This mechanism can perform the required sampling tip replacement operation more efficiently, but it requires an additional de-sampling tip mechanism. The overall structure is relatively complex and large in size, and a large external force needs to be provided when replacing the sampling tip. Due to the limited volume inside the cartridge, it is difficult to set up a large and complex replacement structure or provide a large external force. Currently, there is no relevant technical solution for replacing sampling tips in a closed cartridge. Therefore, there is also an urgent need to design a simple mechanism that can replace sampling tips inside a closed cartridge with a compact space. Summary of the Invention

[0005] To address the deficiencies of the prior art, the present invention proposes a nucleic acid processing closed cartridge and method, which ensures the accuracy of pipetting, expands the applicable range of the cartridge, and further realizes the replacement operation of the pipette tip by utilizing the movement of the pipette tip in the closed cartridge and the structure of the cartridge itself. Correspondingly, the sealing structure between the pipette tip and the pipette tip adapter is optimized to reduce the force required for the installation and detachment of the pipette tip, having the advantages of simple structure, low cost, and strong operability.

[0006] To achieve the above objectives, the technical solutions adopted by the present invention include:

[0007] A nucleic acid processing closed cartridge, characterized in that it includes a base, a pipette tip placement structure, a pipette tip adapter that supports at least three degrees of freedom of displacement, and at least two pipette tips disposed within the cartridge;

[0008] The base includes a reaction area and a non-reaction area;

[0009] The pipette tip placement structure is correspondingly disposed at the non-reaction area position of the base, and the pipette tip placement structure includes at least two pipette tip replacement positions;

[0010] The pipette tip adapter is displaced to replace the pipette tip at the pipette tip placement structure, and after the pipette tip adapter is assembled with the pipette tip, it is moved to the reaction area for pipetting operation.

[0011] Further, the non-reaction area of the base is disposed close to the inner wall of the cartridge, and the pipette tip placement structure is fixedly disposed at the position corresponding to the non-reaction area on the inner wall of the cartridge.

[0012] Further, the pipette tip placement structure includes a first baffle and a second baffle disposed in sequence from top to bottom. The height difference between the first baffle and the second baffle allows at least the connection end of the pipette tip to be accommodated. The first baffle is provided with at least two juxtaposed first U-shaped openings, and the second baffle is provided with at least two second U-shaped openings respectively corresponding to the first U-shaped openings. Each set of corresponding first U-shaped openings and second U-shaped openings on the first baffle and the second baffle independently form a pipette tip replacement position;

[0013] The pipette tip adapter is fixedly disposed on a driving mechanism that supports at least three degrees of freedom of displacement. The driving mechanism supports at least vertical displacement, horizontal left-right displacement approaching / away from the pipette tip placement structure, and horizontal depth displacement for switching the pipette tip adapter to point to the pipette tip replacement position;

[0014] The size of the first U-shaped opening allows at least the vertical passage of the pipette tip adapter; the size of the second U-shaped opening allows at least the main body of the pipette tip to enter; the sizes of the first U-shaped opening and the second U-shaped opening do not allow the vertical passage of the connection end of the pipette tip.

[0015] Further, the pipette tip placement structure further includes a fixing block made of an elastic material. The fixing block is provided with at least two C-shaped limiting grooves corresponding to the first U-shaped openings respectively. The C-shaped limiting grooves surround and fasten the main body of the pipette tip, so that each group of corresponding first U-shaped openings, second U-shaped openings and C-shaped limiting grooves on the first baffle, the second baffle and the fixing block independently form a pipette tip replacement position.

[0016] Further, at least one O-ring is provided on the outer surface of the pipette tip adapter, and the O-ring is installed in the installation groove on the outer surface of the pipette tip adapter.

[0017] Further, the pipette tip adapter is further provided with an installation limiting structure, and the installation limiting structure contacts the upper surface of the pipette tip connection end when the pipette tip adapter vertically moves downward to limit the vertical displacement position of the pipette tip adapter.

[0018] Further, the horizontal depth displacement is a linear displacement of the pipette tip adapter in the depth direction, or the horizontal depth displacement is a swinging displacement of the pipette tip adapter.

[0019] The present invention also relates to a nucleic acid processing method, characterized in that a pipette tip replacement operation is performed using the closed cartridge as described above.

[0020] Further, the method includes:

[0021] Setting a first working height and a second working height of the pipette tip adapter. The first working height is the working position where the pipette tip adapter is completely separated from the pipette tip, and the second working height is the working position where the pipette tip adapter is adaptively installed with the pipette tip.

[0022] Further, the method further includes that when the pipette tip adapter needs to replace the currently adaptively installed pipette tip, the following steps are performed:

[0023] S1. Keep the pipette tip adapter at the second working height through vertical displacement;

[0024] S2. Switch the pipette tip adapter to the pipette tip replacement position corresponding to the pipette tip to be separated through horizontal depth displacement;

[0025] S3. Make the pipette tip adapter approach the pipette tip placement structure through horizontal left-right displacement until the main body of the currently adaptively installed pipette tip is surrounded and fastened by the C-shaped limiting groove;

[0026] S4. Make the pipette tip adapter rise to the first working height through vertical displacement to be completely separated from the currently adaptively installed pipette tip;

[0027] S5. Switch the pipette tip adapter to point to the pipette tip replacement position where the pipette tip to be replaced and installed is located by horizontal depth displacement;

[0028] S6. Lower the pipette tip adapter to the second working height by vertical displacement to adapt and install it with the pipette tip to be replaced and installed;

[0029] S7. Move the pipette tip adapter horizontally to the left and right to move it away from the pipette tip placement structure, and the main body of the replaced and installed pipette tip is disengaged from the C-shaped limit groove for clamping and fastening.

[0030] Furthermore, step S5 further includes:

[0031] Move the pipette tip adapter horizontally to the left and right to move it away from the pipette tip placement structure, then switch the pipette tip adapter to point to the pipette tip replacement position where the pipette tip to be replaced and installed is located by horizontal depth displacement, and move the pipette tip adapter horizontally to the left and right to approach the pipette tip placement structure until the pipette tip adapter is vertically aligned with the pipette tip to be replaced and installed.

[0032] The beneficial effects of the present invention are:

[0033] By using the nucleic acid processing closed cartridge and method of the present invention, the accuracy of pipetting is ensured by increasing the replaceable pipette tip, the applicable range of the cartridge is improved, and further, the replacement operation of the pipette tip is realized by using the pipette tip movement action in the closed cartridge and the structure of the cartridge itself. The complete installation and separation operations of the pipette tip are realized in the very limited internal space of the closed cartridge. Compared with various existing pipette tip replacement schemes, the device has a very significant volume advantage and a simple structure. The relatively low cost also makes it particularly suitable for disposable use scenarios such as nucleic acid processing cartridges, and will not cause an obvious burden on the experimental cost; the corresponding optimized sealing structure between the pipette tip and the pipette tip adapter reduces the force required for pipette tip installation and detachment, and has strong operability. Description of the Drawings

[0034] Figure 1 It is a schematic structural diagram of a preferred embodiment of the nucleic acid processing closed cartridge of the present invention.

[0035] Figure 2 It is a schematic diagram of the first position of the pipette tip adapter of the preferred embodiment of the present invention.

[0036] Figure 3 It is a schematic diagram of the second position of the pipette tip adapter of the preferred embodiment of the present invention.

[0037] Figure 4 It is a partial schematic diagram of the combination of the pipette tip adapter and the pipette tip of the preferred embodiment of the present invention.

[0038] Figure 5 This is a schematic diagram of the main structure of the pipette tip adapter body in the preferred embodiment of the present invention.

[0039] Figure 6 This is a schematic diagram of the fixing block in the preferred embodiment of the present invention.

[0040] Explanation of the drawing reference numbers: 1 - base, 11 - reaction area, 12 - non-reaction area, 2 - pipette tip placement structure, 21 - first baffle, 211 - first U-shaped opening, 22 - second baffle, 221 - second U-shaped opening, 23 - fixing block, 231 - C-shaped limiting groove, 3 - pipette tip adapter, 31 - driving mechanism, 32 - O-ring, 33 - installation limiting structure, 4 - pipette tip. Detailed implementation manners

[0041] In order to understand the content of the present invention more clearly, it will be described in detail in combination with the drawings and embodiments.

[0042] As Figures 1 to 3 shown in the figure is a schematic diagram of a preferred embodiment of the nucleic acid processing closed cartridge of the present invention. By hiding part of the cartridge wall surface, the relevant structures inside the closed cartridge are shown. The main components include a base 1, a pipette tip placement structure 2, and a pipette tip adapter 3.

[0043] Among them, the base 1 refers to the reagent holes or reaction hole tray structure in the closed cartridge mainly used for containing reaction reagents, etc. In the preferred embodiment, the main function of the base 1 is the same as that of the prior art. However, in order to better support the replacement operation of the pipette tip 4, a non-reaction area 12 is provided at a position close to one side wall of the cartridge, so that the temporarily unused pipette tip 4 can be safely stored without affecting the normal progress of the experiment in the cartridge. Preferably, no reagent holes or reaction holes are provided in the non-reaction area 12, making it clearly distinguishable from the reaction area 11 of the base 1 provided with a number of reagent holes or reaction holes. Of course, it is easy for those skilled in the art to understand that the setting of the non-reaction area 12 and the reaction area 11 can be merely a logical division of the relevant functional areas of the base 1, rather than any significant difference in the necessary structure. For example, the unused reagent holes or reaction holes at the edge position of the base 1 or close to the edge that do not undertake experimental functions can be used as the non-reaction area 12 to safely store the pipette tip 4.

[0044] Excluding the base 1 part, the main innovation point of the preferred embodiment is the design of the pipette tip placement structure 2, which combines with the original driving mechanism 31 of the closed cartridge to drive the pipette tip adapter 3 to perform corresponding displacement operations to achieve the required pipette tip 4 installation and separation effects. As Figure 2The diagram shows a schematic diagram of the pipette adapter 3 in the first position, which refers to a position of the pipette adapter 3 away from the pipette placement structure 2 (non-reaction area 12), for example, a normal working position for performing pipetting operation at the reaction area 11 of the base 1. In the first position, the pipette placement structure 2 disposed on the inner wall of the cartridge and the pipette 4 temporarily stored on the pipette placement structure 2 will not affect the various normal displacement operations of the pipette adapter 3, so that the pipette adapter 3 assembled with the pipette 4 can provide all necessary functions of the pipette in combination with other cartridge components ( Figure 2 In order to facilitate the display of the pipette tip adapter 3, the pipette tip 4 which can be optionally installed on the pipette tip adapter 3 is hidden.

[0045] The sample pipette tip placement structure 2 mainly includes a first baffle 21, a second baffle 22 and a fixing block 23 which are arranged in sequence from top to bottom. The positions where the first baffle 21 and the second baffle 22 are arranged have a certain height apart, and a reserved position for accommodating the sample pipette tip 4 is formed by combining a plurality of first U-shaped openings 211 and second U-shaped openings 221 (in the preferred embodiment, there are three first U-shaped openings 211 and second U-shaped openings 221, respectively) which are arranged correspondingly on the first baffle 21 and the second baffle 22. The connecting end of the sample pipette tip 4 is the part with the largest diameter at the top of the sample pipette tip 4. By adjusting the size of the first U-shaped opening 211 and the second U-shaped opening 221, the main part of the sample pipette tip 4 below the connecting end can be embedded in the second U-shaped opening 221, and the connecting end will be vertically limited by the second U-shaped opening 221 and the first U-shaped opening 211, forming a hanging type of sample pipette tip 4 placement method. The sizes of the first U-shaped opening 211 and the second U-shaped opening 221 are constant, that is, the first baffle 21 and the second baffle 22 are made of stable hard materials, so that they can withstand a certain external force without changing their shapes, thereby ensuring that the temporarily stored sample pipette tips 4 cannot enter or leave the sample pipette tip placement structure 2 upward or downward by vertical displacement, but must adopt horizontal linear displacement to enter or leave the sample pipette tip placement structure 2 from the opening pointing direction of the first U-shaped opening 211 and the second U-shaped opening 221.

[0046] The fixing block 23 is a deformable component made of elastic material, preferably arranged close to the lower surface of the second baffle 22, and is provided with a corresponding number of C-shaped limiting grooves 231 (such as Figure 6 The size of the C-shaped limiting groove 231 matches the main body of the sample pipette tip 4, so that when the sample pipette tip 4 is placed, the fixing block 23 elastically embraces and tightens the main body of the sample pipette tip 4, which can limit the shaking of the sample pipette tip 4 and ensure that the end opening position of the sample pipette tip 4 is fixed, so that the sample pipette tip adapter 3 is easy to align with the sample pipette tip 4 that needs to be replaced.

[0047] Overall, each set of corresponding first U-shaped openings 211, second U-shaped openings 221, and C-shaped limiting grooves 231 on the first baffle 21, second baffle 22, and fixing block 23 independently form a pipette tip replacement position. In a preferred embodiment, three pipette tip replacement positions are arranged side by side to support three replaceable pipette tips 4 in the closed cassette. When one pipette tip 4 is installed on the pipette tip adapter 3 for experimental operations, the pipette tip placement structure 2 temporarily stores the other two pipette tips 4, leaving one pipette tip replacement position vacant. It is easy to understand that for pipette tips 4 of different specifications and sizes, the sizes of the first U-shaped opening 211, second U-shaped opening 221, and C-shaped limiting groove 231 can be simply changed so that the pipette tip placement structure 2 can match and accommodate them. Correspondingly, when programming the control program of the closed cassette, the pipette tip replacement position corresponding to each pipette tip 4 should be calibrated at the same time so that it can be correctly stored in the pipette tip placement structure 2.

[0048] As Figure 3 shown is a schematic diagram of the pipette tip adapter 3 in the second position. The second position refers to the position where the pipette tip adapter 3 aligns with a specific pipette tip replacement position on the pipette tip placement structure 2 for pipette tip 4 placement or installation operations. The displacement of the pipette tip adapter 3 is driven by a drive mechanism 31 that supports at least three degrees of freedom of displacement. The drive structure preferably uses the commonly used lead screw drive method in the closed cassette, which is driven by a power source outside the cassette to rotate to achieve the corresponding displacement operation. The specific structure has been publicly disclosed in some prior arts and will not be elaborated here. The combination of the pipette tip adapter 3 and the pipette tip 4 of the present invention can be understood as being equivalent to the closed cassette pipettor in the prior art in terms of experimental function, except that the replacement of the pipette tip 4 is achieved through the three degrees of freedom displacement of the drive mechanism 31. It should be noted that the three degrees of freedom displacement of the drive mechanism 31 is not deliberately set to achieve the replacement of the pipette tip 4. There already exists a similar drive displacement form in the prior art. The innovation of the present invention lies in the use of the existing three degrees of freedom displacement ability to achieve an additional pipette tip 4 replacement function.

[0049] The specific implementation method is to achieve the matching alignment of the pipette tip adapter 3 and the pipette tip 4 (pipette tip replacement position) by calibrating the horizontal left and right displacement approaching / away from the pipette tip placement structure 2 and the horizontal depth displacement that switches the pipette tip adapter 3 to point to the pipette tip replacement position, and then achieve the assembly or separation operation between the pipette tip adapter 3 and the pipette tip 4 by calibrating the vertical displacement.

[0050] Thus, it can be seen that the pipette tip adapter 3 is displaced from the first position shown in Figure 2 to the one shown in Figure 3The second position shown (the pipette tip 4 in the attached drawing is only for illustrative purposes), a horizontal in-depth displacement alignment is required to match the replacement position of the pipette tip to be replaced, and then it is moved to the corresponding position (non-reaction zone 12) through horizontal left and right displacement, so that the pipette tip adapter 3 accurately aligns with the pipette tip 4 (pipette tip replacement position). Preferably, the horizontal in-depth displacement can be the linear displacement of the pipette tip adapter 3 in the in-depth direction, or the swinging displacement of the pipette tip adapter 3.

[0051] For the assembly and disassembly operations between the pipette tip adapter 3 and the pipette tip 4, they are realized by inserting and pulling out the end of the pipette tip adapter 3 into and out of the opening of the pipette tip 4. The downward force generated during insertion is borne by the second baffle 22, and the upward force generated during pulling out is borne by the first baffle 21. Preferably, the pipette tip adapter 3 is also provided with an installation limit structure 33, such as Figure 5 As shown in the schematic diagram of the main structure of the pipette tip adapter 3, the installation limit structure 33 is a protruding fixing piece. When the pipette tip adapter 3 vertically moves downward, the position of the installation limit structure 33 is at the opening of the first U-shaped opening 211, so that it will first contact the upper surface of the connection end of the pipette tip 4 to ensure that the overall height after the connection between the pipette tip adapter 3 and the pipette tip 4 is consistent.

[0052] Preferably, at least one O-ring 32 is provided on the outer surface of the pipette tip adapter 3, and the O-ring 32 is installed in the installation groove on the outer surface of the pipette tip adapter 3 to ensure the airtightness between the pipette tip 4 and the pipette tip adapter 3. The structure after the combination of the pipette tip adapter 3 and the pipette tip 4 is as Figure 4 shown, in Figure 4 the state shown, the pipette tip adapter 3 and the pipette tip 4 have been completely matched and combined, the installation limit structure 33 contacts the upper surface of the connection end of the pipette tip 4, but the pipette tip 4 is still placed on the pipette tip placement structure 2 and has not been removed. In this state, it can be seen that the end of the pipette tip adapter 3 has been inserted into the opening of the pipette tip 4, and at the same time, the O-ring 32 ensures the airtightness between the two.

[0053] When specifically replacing the pipette tip 4 using the above-described preferred embodiment, first set the first working height and the second working height of the pipette tip adapter 3. The first working height is the working position where the pipette tip adapter 3 is completely separated from the pipette tip 4, and the second working height is the working position where the pipette tip adapter 3 is adaptively installed with the pipette tip 4, and the following steps are performed:

[0054] S1. Keep the pipette tip adapter 3 at the second working height through vertical displacement;

[0055] S2. Switch the tip adapter to the tip replacement position corresponding to the pipetting tip 4 to be separated by horizontal depth displacement;

[0056] S3. Make the pipetting tip adapter 3 approach the pipetting tip placement structure 2 by horizontal left - right displacement until the main body of the currently adaptively installed pipetting tip 4 is surrounded and fastened by the C - shaped limiting groove 231;

[0057] S4. Make the pipetting tip adapter 3 rise to the first working height by vertical displacement to completely separate from the currently adaptively installed pipetting tip 4;

[0058] S5. Switch the tip adapter to the tip replacement position where the pipetting tip 4 to be replaced is located by horizontal depth displacement. In particular, before performing the horizontal depth displacement, first make the pipetting tip adapter 3 move away from the pipetting tip placement structure 2 by horizontal left - right displacement to avoid limited horizontal depth displacement;

[0059] S6. Make the pipetting tip adapter 3 descend to the second working height by vertical displacement to be adaptively installed with the pipetting tip 4 to be replaced;

[0060] S7. Make the pipetting tip adapter 3 move away from the pipetting tip placement structure 2 by horizontal left - right displacement, so that the main body of the replaced pipetting tip 4 is disengaged from the surrounding and fastening of the C - shaped limiting groove 231, and the pipetting tip adapter 3 drives the pipetting tip 4 to move horizontally along the opening direction of the U - shaped opening, so that the pipetting tip 4 moves out from the U - shaped opening on the side wall.

[0061] It is easy to think that the putting - back operation of the pipetting tip 4 can be completed by performing a part of the above steps, so that the pipetting tip adapter 3 is vacant, or a specific pipetting tip 4 can be selected for installation on the vacant pipetting tip adapter 3.

[0062] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A nucleic acid processing closed cartridge, characterized in that, It includes a base, a pipette tip placement structure, a pipette tip adapter that supports at least three - degree - of - freedom displacement, and at least two pipette tips, which are arranged inside the cartridge; The base includes a reaction area and a non - reaction area; The pipette tip placement structure is correspondingly arranged at the non - reaction area position of the base. The pipette tip placement structure includes at least two pipette tip replacement positions; The pipette tip adapter displaces and replaces the pipette tip at the pipette tip placement structure. After the pipette tip adapter is assembled with the pipette tip, it moves to the reaction area for pipetting operation; The pipette tip placement structure includes a first baffle and a second baffle arranged in sequence from top to bottom. The height between the first baffle and the second baffle allows at least the connection end of the pipette tip to be accommodated. The first baffle is provided with at least two juxtaposed first U - shaped openings, and the second baffle is provided with at least two second U - shaped openings corresponding to the first U - shaped openings respectively. Each group of corresponding first U - shaped openings and second U - shaped openings on the first baffle and the second baffle independently form a pipette tip replacement position; The pipette tip adapter is fixedly arranged on a driving mechanism that supports at least three - degree - of - freedom displacement. The driving mechanism supports at least vertical displacement, horizontal left - right displacement for approaching / leaving the pipette tip placement structure, and horizontal depth displacement for switching the pipette tip adapter to point to the pipette tip replacement position; The size of the first U - shaped opening allows at least the vertical passage of the pipette tip adapter; the size of the second U - shaped opening allows at least the body of the pipette tip to enter; the sizes of the first U - shaped opening and the second U - shaped opening do not allow the vertical passage of the connection end of the pipette tip; The downward force generated when the pipette tip adapter inserts into the pipette tip is borne by the second baffle, and the upward force generated when the pipette tip adapter pulls out the pipette tip is borne by the first baffle.

2. The enclosed card case according to claim 1, characterized in that, The non - reaction area of the base is arranged close to the inner wall of the cartridge, and the pipette tip placement structure is fixedly arranged at the position of the inner wall of the cartridge corresponding to the non - reaction area.

3. The enclosed card case according to claim 1, wherein The pipette tip placement structure further includes fixing blocks. The fixing blocks are made of elastic materials. The fixing blocks are provided with at least two C - shaped limiting grooves corresponding to the first U - shaped openings respectively. The C - shaped limiting grooves surround and fasten the body of the pipette tip, so that each group of corresponding first U - shaped openings, second U - shaped openings and C - shaped limiting grooves on the first baffle, the second baffle and the fixing blocks independently form a pipette tip replacement position.

4. The enclosed card case according to claim 1, wherein At least one O - ring is arranged on the outer surface of the pipette tip adapter, and the O - ring is installed in the installation groove on the outer surface of the pipette tip adapter.

5. The enclosed card case according to claim 3, characterized in that, The pipette tip adapter is further provided with an installation limiting structure. The installation limiting structure contacts the upper surface of the connection end of the pipette tip when the pipette tip adapter vertically displaces downward to limit the vertical displacement position of the pipette tip adapter.

6. The enclosed card case according to claim 1, wherein The horizontal depth displacement is a linear displacement of the pipette tip adapter in the depth direction, or the horizontal depth displacement is a swinging displacement of the pipette tip adapter.

7. A nucleic acid processing method, characterized in that, Perform a pipette tip replacement operation using the closed - type cartridge according to any one of claims 1 to 5.

8. The method according to claim 7, wherein The method includes: Set the first working height and the second working height of the pipette tip adapter. The first working height is the working position where the pipette tip adapter is completely separated from the pipette tip, and the second working height is the working position where the pipette tip adapter is adaptively installed with the pipette tip.

9. The method according to claim 8, wherein The method further includes, when the pipette tip adapter needs to replace the currently adaptively installed pipette tip, performing the following steps: S1. Keep the pipette tip adapter at the second working height through vertical displacement; S2. Switch the tip adapter to the pipette tip replacement position corresponding to the pipette tip to be separated through horizontal depth displacement; S3. Make the pipette tip adapter approach the pipette tip placement structure through horizontal left - right displacement until the body of the currently adaptively installed pipette tip is tightly held by the C - shaped limiting groove; S4. Make the pipette tip adapter rise to the first working height through vertical displacement to be completely separated from the currently adaptively installed pipette tip; S5. Switch the tip adapter to the pipette tip replacement position where the pipette tip to be replaced and installed is located through horizontal depth displacement; S6. Make the pipette tip adapter descend to the second working height through vertical displacement to be adaptively installed with the pipette tip to be replaced and installed; S7. Make the pipette tip adapter move away from the pipette tip placement structure through horizontal left - right displacement so that the body of the replaced and installed pipette tip is disengaged from the tight holding of the C - shaped limiting groove.

10. The method according to claim 9, wherein The step S5 further includes: Make the pipette tip adapter move away from the pipette tip placement structure through horizontal left - right displacement, then switch the tip adapter to the pipette tip replacement position where the pipette tip to be replaced and installed is located through horizontal depth displacement, and make the pipette tip adapter approach the pipette tip placement structure through horizontal left - right displacement until the tip adapter is vertically aligned with the pipette tip to be replaced and installed.

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