A digital PCR instrument for trace nucleic acid detection

Abstract

The application relates to a digital PCR instrument for trace nucleic acid detection, mainly comprising an instrument body, a placing groove, a bearing table, a reaction chip and an optical cover plate, the bearing table is fixed in the placing groove arranged on the instrument body, the reaction chip is detachably installed on the bearing table, and the optical cover plate and the reaction chip form a cooperation structure which can be pressed and separated. Rapid positioning is realized through cooperation of a conical positioning column and a positioning hole, horizontal rotation is prevented through cooperation of an anti-rotation positioning column and a prism hole, a sealing mechanism comprises a sealing gasket arranged at the bottom of the optical cover plate and an annular convex rib on the reaction chip, and the annular convex rib and the annular groove at the bottom of the optical cover plate form a labyrinth sealing structure; the structure guarantees sealing reliability in the detection process through double sealing, simultaneously ensures assembly repeatability through multi-point positioning, and effectively improves the accuracy and operation convenience of trace nucleic acid detection.

Description

Technical Field

[0001] This utility model relates to the field of digital PCR instrument technology, and in particular to a digital PCR instrument for trace nucleic acid detection. Background Technology

[0002] In the field of trace nucleic acid detection, digital PCR technology is widely used because it can achieve absolute quantification of nucleic acid molecules. This technology divides the reaction system into a large number of independent micro-units for amplification reaction, and then achieves accurate quantification through fluorescence signal statistics. Currently, digital PCR instruments on the market usually contain core components such as reaction chips and optical detection systems.

[0003] However, in actual use, the reliability of the seal between the reaction chip and the optical system has always affected the detection accuracy. Common sealing methods often use a single sealing ring structure, which is prone to deterioration in sealing performance due to material aging after multiple thermal cycles. Pressure fluctuations caused by temperature changes can cause trace evaporation of the reaction liquid, changing the concentration of the reaction system and thus affecting the final quantitative results. In addition, insufficient positioning accuracy of the reaction chip can lead to incomplete signal acquisition during optical detection. These factors restrict the accuracy and repeatability of the detection results. In terms of sealing, simply relying on increasing the pre-tightening force of the sealing ring can cause deformation of the reaction chip, affecting the integrity of the micro-chamber structure.

[0004] Therefore, a structural solution is needed that can ensure both accurate positioning and reliable sealing. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of existing digital PCR instruments for trace nucleic acid detection, which rely solely on increasing the pre-tightening force of the sealing ring, causing deformation of the reaction chip and affecting the integrity of the microchamber structure. Therefore, this invention proposes a digital PCR instrument for trace nucleic acid detection.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A digital PCR instrument for trace nucleic acid detection includes an instrument body, a placement slot on the instrument body, a support platform fixed in the placement slot, a reaction chip detachably connected to the support platform, and an optical cover plate detachably pressed onto the reaction chip. A sealing mechanism is provided between the reaction chip and the optical cover to prevent the detection accuracy from being affected by sealing problems during the detection process.

[0007] Furthermore, the sealing mechanism includes a sealing gasket fixed to the bottom of the optical cover plate. When the optical cover plate and the reaction chip are pressed together, the bottom of the sealing gasket and the bottom of the reaction chip are sealed and fitted together, and the optical cover plate and the reaction chip do not come into contact.

[0008] Furthermore, the sealing mechanism also includes two annular ribs fixedly disposed on the top of the reaction chip, and two annular groove plates disposed on the bottom of the optical cover plate, with annular grooves adapted to the corresponding annular ribs on the bottom of the two annular groove plates. On the one hand, it can play a certain positioning role, and on the other hand, it can still ensure the sealing performance when the sealing gasket ages.

[0009] Furthermore, the top of the support platform is fixed with two symmetrically arranged conical positioning posts, and the top of the reaction chip and the optical cover plate are both provided with positioning holes that are symmetrically arranged and correspond to the conical positioning posts for positioning.

[0010] Furthermore, the top of the support platform is fixed with anti-rotation positioning posts arranged in a triangle with the two conical positioning posts, and the top of the reaction chip and the optical cover plate are both provided with prism holes that cooperate with the anti-rotation positioning posts.

[0011] Furthermore, a rotating cover is mounted on the instrument body via a rotating shaft. The rotating cover can seal the opening of the placement slot to prevent external interference from entering the interior of the placement slot and affecting the test results.

[0012] In this invention, a digital PCR instrument for trace nucleic acid detection uses a conical positioning post and a beveled positioning hole to automatically orient the reaction chip during placement. This allows the operator to quickly complete the positioning without repeated adjustments. The square fit between the anti-rotation positioning post and the prism hole effectively prevents the chip from rotating slightly during thermal cycling, thus avoiding optical detection errors caused by positional shifts. The dual-sealing structure significantly improves the reliability of the equipment. The upper silicone gasket achieves initial sealing through elastic deformation during compression, while the lower labyrinth seal forms secondary protection through the cooperation of annular ribs and annular grooves. Even if the gasket ages slightly after a long period of use, this design can still maintain a good overall sealing effect and reduce changes in the concentration of the reaction liquid caused by evaporation. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the front view of a digital PCR instrument for trace nucleic acid detection proposed in this utility model; Figure 2 This is a schematic diagram of the reaction chip and optical cover plate of a digital PCR instrument for trace nucleic acid detection proposed in this utility model, in a pressed state. Figure 3 This is a schematic diagram of the separation state structure of the reaction chip and optical cover plate of a digital PCR instrument for trace nucleic acid detection proposed in this utility model; Figure 4This invention proposes a digital PCR instrument for trace nucleic acid detection. Figure 1 Enlarged schematic diagram of part A in the middle.

[0014] In the diagram: 1. Instrument body; 2. Placement slot; 3. Rotating cover; 4. Support platform; 5. Conical positioning post; 6. Anti-rotation positioning post; 7. Reaction chip; 8. Optical cover plate; 9. Positioning hole; 10. Prismatic hole; 11. Sealing gasket; 12. Annular rib; 13. Annular groove plate. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0016] In one embodiment Reference Figure 1-4 A digital PCR instrument for trace nucleic acid detection includes an instrument body 1, which is made of ABS engineering plastic and has sufficient structural strength and dimensional stability. The placement slot 2 on the instrument body 1 is used to accommodate the entire core detection component. The inner surface of the slot is smoothed for easy cleaning. Before starting the test, open the rotating cover 3. The rotating cover 3 is installed on the instrument body 1 through a stainless steel rotating shaft, which can rotate the opening of the placement slot 2. The operator takes out the disposable reaction chip 7 from the packaging. The reaction chip 7 is injection molded from medical grade polycarbonate and has excellent optical transparency and biocompatibility. Place it on the support stage 4. The support stage 4 is made of aluminum alloy and the surface is anodized, which has good thermal conductivity and corrosion resistance. When placing the chip, make sure to align the positioning hole 9 at the bottom of the reaction chip 7 with the conical positioning post 5 on the support platform 4. The conical positioning post 5 is made of zirconia ceramic material, which has high hardness and low coefficient of thermal expansion. Due to the inclined guide of the conical positioning post 5, even if there is a small positional deviation, the chip can automatically slide into the correct position under the action of gravity. At the same time, the prism hole 10 on the reaction chip 7 will cooperate with the anti-rotation positioning post 6. The anti-rotation positioning post 6 is also made of zirconia ceramic material, and its cross-section is square, which can effectively prevent the chip from rotating in the horizontal plane. After placing the reaction chip 7, use a micropipette to add the prepared PCR reaction solution to the designated sample application area of ​​the reaction chip 7. The reaction solution will automatically fill each microreaction chamber through the microchannels inside the chip. After completion, remove the optical cover plate 8. The main body of the optical cover plate 8 is made of polymethyl methacrylate and has good optical properties. Align it with the reaction chip 7 below. The positioning hole 9 at the bottom of the optical cover plate 8 also needs to be aligned with the conical positioning post 5 and the anti-rotation positioning post 6 on the support stage 4. When the optical cover plate 8 is slowly pressed down, the sealing gasket 11 fixed at the bottom of the optical cover plate 8 will first contact the upper surface of the reaction chip 7. The sealing gasket 11 is made of medical-grade silicone material. Under pressure, it will deform appropriately and fit tightly against the chip surface, forming the first sealing barrier. As the optical cover plate 8 continues to be pressed down, the annular rib 12 on the top of the reaction chip 7 will gradually embed into the annular groove on the annular groove plate 13 at the bottom of the optical cover plate 8. The annular rib 12 and the annular groove plate 13 are both made of the same polycarbonate material as the reaction chip 7 to ensure that the coefficient of thermal expansion is consistent. The cross-section of these annular ribs 12 is semi-circular and the height is about 0.5 mm. The contour of the annular groove matches the shape of the rib, but leaves a 0.1 mm fitting gap. This labyrinthine fit forms the second sealing barrier. After the pressure is applied, the rotating cover 3 is closed. The rotating cover 3 is lined with polyurethane foam material, which will not apply excessive pressure to the optical cover plate 8 below when it is closed. At this time, the detection system is in a completely sealed state. When the detection begins, the temperature control system is activated and the heating and cooling elements inside the stage 4 start to work. Through precise temperature control, the nucleic acid sample in the reaction chip 7 is amplified. The optical detection system is located above the optical cover plate 8 and collects the fluorescence signal of each microchamber through the transparent window on the cover plate. After the test, open the rotating cover 3 and gently lift the optical cover 8 to separate it from the reaction chip 7. The used reaction chip 7 can be disposed of as medical waste. The optical cover 8 can be reused after being wiped and disinfected with 75% ethanol. Practical application shows that after 100 reuses, the sealing gasket 11 still maintains good elasticity, and the mating parts of the annular rib 12 and the annular groove do not show obvious wear, thus continuing to ensure reliable sealing performance.

[0017] However, as is well known to those skilled in the art, the working principles and wiring methods of the instrument body 1, the reaction chip 7, and the optical cover plate 8 are all conventional means or common knowledge, and will not be described in detail here. Those skilled in the art can make any selections according to their needs or convenience.

[0018] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A digital PCR instrument for trace nucleic acid detection, used in trace nucleic acid detection operations, characterized in that, Includes an instrument body (1), the instrument body (1) is provided with a placement groove (2), a support platform (4) is fixedly provided in the placement groove (2), a reaction chip (7) is detachably connected to the support platform (4), and an optical cover plate (8) is detachably pressed onto the reaction chip (7). A sealing mechanism is provided between the reaction chip (7) and the optical cover plate (8) to prevent the detection accuracy from being affected by sealing problems during the detection process.

2. The digital PCR instrument for trace nucleic acid detection according to claim 1, characterized in that, The sealing mechanism includes a sealing gasket (11) fixed to the bottom of the optical cover plate (8). When the optical cover plate (8) and the reaction chip (7) are pressed together, the bottom of the sealing gasket (11) and the bottom of the reaction chip (7) are sealed and fitted together, and the optical cover plate (8) and the reaction chip (7) do not contact each other.

3. A digital PCR instrument for trace nucleic acid detection according to claim 1, characterized in that, The sealing mechanism also includes two annular ribs (12) fixedly disposed on the top of the reaction chip (7) in an inner and outer manner. The bottom of the optical cover plate (8) is fixedly provided with two annular groove plates (13) arranged in an inner and outer manner. The bottom of the two annular groove plates (13) is provided with annular grooves that are adapted to the corresponding annular ribs (12). On the one hand, it can play a certain positioning role, and on the other hand, it can still ensure the sealing performance when the sealing gasket (11) ages.

4. A digital PCR instrument for trace nucleic acid detection according to claim 1, characterized in that, The top of the support platform (4) is fixed with two symmetrically arranged conical positioning posts (5), and the top of the reaction chip (7) and the optical cover plate (8) are both provided with symmetrically arranged positioning holes (9) for positioning in conjunction with the corresponding conical positioning posts (5).

5. A digital PCR instrument for trace nucleic acid detection according to claim 4, characterized in that, The top of the support platform (4) is fixed with an anti-rotation positioning post (6) arranged in a triangle with the two conical positioning posts (5). The top of the reaction chip (7) and the optical cover plate (8) are both provided with prism holes (10) that cooperate with the anti-rotation positioning post (6).

6. A digital PCR instrument for trace nucleic acid detection according to claim 1, characterized in that, The instrument body (1) is equipped with a rotating cover (3) which is rotated on a shaft. The rotating cover (3) can seal the opening of the placement slot (2) to prevent external interference from entering the interior of the placement slot (2) and affecting the detection results.

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