CN211947024U - PCR test tube - Google Patents

Abstract

The utility model provides a lumen volume is little, can reduce the reaction system, simultaneously can the contact heat transfer of large tracts of land, and the fast PCR test tube of alternating temperature, its whole is the platykurtic, including upper end open-ended body and be used for shutoff open-ended tube cap, the lower part has the communicating lumen with the opening in the body. Two channels are arranged in the tube body; the lower ends of the two channels are communicated with the tube cavity, but the positions of the lower ends of the two channels communicated with the tube cavity are different; the channel at the higher position of the position communicated with the tube cavity is an air inlet channel, and the channel at the lower position of the position communicated with the tube cavity is a reflux channel; the outlet at the upper end of the air inlet channel and the inlet at the upper end of the backflow channel are both positioned on the surface of the pipe body contacted with the pipe cover.

Description

PCR test tube

Technical Field

The application relates to experimental equipment in the technical field of biology, in particular to a PCR instrument and a PCR test tube.

Background

Currently, in the field of molecular biology, PCR is a commonly used experimental technique, and PCR, i.e., Polymerase Chain Reaction (PCR), is a method for in vitro enzymatic synthesis of specific DNA fragments.

The PCR (thermal cycle) instrument manufactured based on polymerase is actually a temperature control device, a PCR test tube (an amplification tube, a thin-wall tube and a reaction tube) is a reaction vessel commonly used in the PCR instrument, a typical PCR amplification reaction is completed by repeatedly heating and cooling the PCR test tube placed in the PCR instrument through the PCR instrument, and in the process, the temperature conduction is realized by heating a metal block by the PCR instrument and transferring the metal block to the PCR test tube placed in the PCR instrument, and then transferring the metal block to PCR reaction liquid in the tube through the tube wall of the PCR test tube, so that the amplification reaction is initiated.

CN201611132547.2 discloses a PCR test tube, includes at least one end open-ended body, be provided with the heat-transfer portion on some pipe walls of body. It prevents the excessive temperature reduction in the pipe that test tube calorific loss leads to through reducing heat conduction portion area. However, the PCR tube still has a large volume, the sample usage amount is at least hundreds of microliters, the PCR tube has certain thermal inertia, and the heating or cooling needs to be long.

CN201710061407.9 discloses a portable microfluidic PCR instrument, which can perform polymerase chain reaction, and can realize fluorescent quantitative detection of gene samples by collecting reaction cycle fluorescent images through a fluorescent signal collecting unit. The device comprises a control unit, a PCR chip (equivalent to a PCR test tube), a temperature control unit and a fluorescence signal acquisition unit, wherein the temperature control unit and the fluorescence signal acquisition unit are connected with the control unit; the PCR chip comprises a substrate, wherein a reaction chamber is formed on one side end face of the substrate, a sealing cover plate is covered on the reaction chamber, and the reaction chamber is communicated with the outside through capillary-shaped sample inlet and outlet holes arranged on the substrate; the temperature control unit comprises a temperature detector, a heating part and a refrigerating part which form heating or refrigerating for the base body in the PCR chip; the acquisition end of the fluorescence signal acquisition unit is arranged corresponding to one side of the sealing cover plate of the PCR chip so as to acquire a fluorescence image in the reaction chamber.

Because the reaction chamber is communicated with the outside through the capillary-shaped sample inlet hole and the sample outlet hole on the substrate (so as to realize the sample loading in the reaction chamber), the reaction chamber is difficult to process, has high cost even if the processing can be realized, and is not suitable for popularization.

Disclosure of Invention

The application aims to provide the PCR test tube which has small tube cavity volume, can reduce a reaction system, can transfer heat in a large-area contact manner and has high temperature change speed.

The technical scheme for realizing the purpose is as follows: a PCR test tube is flat as a whole and comprises a tube body with an opening at the upper end and a tube cover for plugging the opening, wherein a tube cavity communicated with the opening is arranged at the lower part in the tube body;

two channels are arranged in the tube body; the lower ends of the two channels are communicated with the tube cavity, but the positions of the lower ends of the two channels communicated with the tube cavity are different; the channel at the higher position of the position communicated with the tube cavity is an air inlet channel, and the channel at the lower position of the position communicated with the tube cavity is a reflux channel; the outlet at the upper end of the air inlet channel and the inlet at the upper end of the backflow channel are both positioned on the surface of the pipe body contacted with the pipe cover.

In the PCR test tube, a transition channel is arranged in the tube cover; when the opening is plugged by the pipe cover, the air inlet channel is communicated with the backflow channel through the transition channel.

The PCR tube has a flange on the outer edge of the flat tube, and the thickness of the flange is smaller than that of the flat tube.

In the PCR tube, the flanges are located on the left and right sides of the flat tube.

Foretell PCR test tube, one side lower part and the body of tube cap become the upset and are connected.

The PCR tube described above, the PCR tube is made of a light-transmitting material.

This application provides a PCR appearance simultaneously, and it can accomplish the heating and cooling to the PCR test tube fast for PCR reaction rate promotes by a wide margin.

The PCR instrument comprises two hot plates which are opposite left and right, are provided with heating devices and are heated by the heating devices, and a support is arranged between the left hot plate and the right hot plate; at least one PCR test tube is arranged on the bracket; the bracket is connected with a left-right driving device which drives the bracket to move left and right; the bracket can move leftwards or rightwards under the driving of the left and right driving devices until the left side surface of the flat PCR test tube is respectively contacted with the left hot plate surface, or the right side surface of the PCR test tube is contacted with the right hot plate surface.

As a further improvement to the PCR instrument, when the left side surface of the PCR tube is contacted with the left hot plate, a right air channel is formed between the right side surface of the PCR tube and the right hot plate, so that the right side surface of the PCR tube and the right hot plate are insulated; when the right side of the PCR test tube is contacted with the right hot plate, a left air channel is formed between the left side of the PCR test tube and the left hot plate, so that the heat insulation is realized between the left side of the PCR test tube and the left hot plate. Preferably, it comprises blowing means for causing air to flow through either the left air passage or the right air passage.

As a further improvement to the PCR instrument, the PCR tubes on the bracket have m rows and n columns, wherein m and n are natural numbers larger than 1; the left side of each PCR tube was coplanar and the right side of each PCR tube was coplanar.

As a further improvement of the PCR instrument, the two hot plates are both provided with light through holes opposite to the tube cavity of the PCR test tube, and the left side and the right side of the two opposite hot plates are respectively provided with a fluorescence excitation module and a fluorescence receiving module; the fluorescence excitation module emits excitation light which passes through a light through hole on one hot plate to irradiate the PCR test tube, and the fluorescence emitted by some substances in the reaction liquid in the tube cavity of the irradiated PCR test tube after excitation passes through a light through hole on the other hot plate to be received by the fluorescence receiving module.

As a further improvement to the PCR instrument, the hot plate is made of a light-transmitting material; the left side and the right side of the two opposite hot plates are respectively provided with a fluorescence excitation module and a fluorescence receiving module; the fluorescence that the fluorescence excitation module sent sees through a hot plate and shines the PCR test tube, and the fluorescence that some materials in the reaction solution in the PCR test tube lumen that is shone after arousing is received by fluorescence receiving module behind another hot plate.

As a further improvement to the PCR instrument, the fluorescence excitation module comprises a light source, a first light collecting mirror, an excitation light filter and a second light collecting mirror; the fluorescence receiving module comprises a third light collecting mirror, a fluorescence filter, an imaging lens and a camera; light emitted by the light source is emitted as parallel light after passing through the first light collecting mirror, and then is irradiated to each PCR test tube through the exciting light filter, the second light collecting mirror and the hot plate; fluorescence emitted by the excited substances in the reaction solution in each PCR test tube enters the imaging lens through the third light collecting mirror and the fluorescent filter and is converged on the target surface of the camera. Preferably, the excitation light filter comprises a plurality of excitation light filters capable of transmitting different wavelengths, and each excitation light filter is uniformly distributed on the rotating first disc; the fluorescent filters comprise fluorescent filters which correspond to different exciting light filters and can transmit different wavelengths; all the fluorescent filters are uniformly distributed on the rotating second disk; the first disk and the second disk rotate synchronously.

As a further improvement to the PCR instrument, the fluorescence excitation module comprises a light source, a collimating lens and an excitation light filter; the fluorescence receiving module comprises a fluorescence filter and a light collecting lens; the light emitted by the light source is emitted as parallel light after passing through the collimating lens, and then the reaction solution in the PCR test tube is irradiated by the exciting light filter; the fluorescence emitted by some substances in the reaction liquid after excitation is observed by people or converged on a photoelectric sensor after passing through a fluorescence filter and then a light collecting lens.

The beneficial effect of this patent:

the thin sheet test tube has small tube cavity volume, can reduce the reaction system and can transfer heat in a large area by contact.

The left channel and the right channel of the test tube are communicated with the transition channel to form an internal circulation channel. When the sample is heated and reacted, the evaporated sample enters the air inlet channel from the lower port of the right channel, and flows back to the tube cavity through the transition channel and the backflow channel to form circulation.

The test tube adopts the insertion mode on the support, inserts the after-poppet and can stabilize the centre gripping test tube to guarantee that the both sides surface of support all is less than the left and right sides face of test tube, can guarantee like this that the support compresses tightly the left and right sides face of test tube on the surface of two hot plates steadily, make heat transfer that can be good between hot plate and the test tube.

The plug-in structure on the bracket in the PCR instrument can ensure that the test tube can be plugged in and participate in the reaction, has the characteristic of plug-in and reaction, and is particularly suitable for emergency treatment.

The air passage in the PCR instrument can ensure that the temperature of the hot plate which is not in contact with the test tube does not have great influence on the temperature of the test tube.

For a constant-temperature hot plate type second-order rapid PCR instrument, the two hot plates are in a constant-temperature state, and the process of temperature rise and drop is avoided, so that the reaction speed is greatly improved.

For a three-order rapid PCR instrument, reaction and temperature rise/fall are synchronously overlapped at the same time, so that the reaction time is saved, and the testing speed is improved.

In the process of heating and reacting of each test tube in the PCR instrument, the fluorescence excitation module can emit excitation light in real time, and the fluorescence receiving module can receive fluorescence in real time, so that the real-time fluorescence PCR detector is provided.

The PCR instrument adopts a transmission type fluorescent module system, so that higher excitation energy, higher excitation sensitivity and higher signal-to-noise ratio can be obtained.

Drawings

FIG. 1 is a front view of a PCR apparatus of example 1;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a schematic diagram of a PCR tube;

FIG. 4 is a cross-sectional view C-C of FIG. 3;

FIG. 5 is a cross-sectional view B-B of FIG. 4; (ii) a

FIG. 6 is a schematic diagram of a PCR tube;

FIG. 7 is a top view of a PCR tube attached to a holder;

FIG. 8 is a front view of the PCR apparatus of example 2 (sectional view A-A in FIG. 9);

FIG. 9 is a top view of FIG. 8;

FIG. 10 is a schematic view of a fluorescence excitation module;

FIG. 11 is a schematic view of a fluorescence receiving module;

FIG. 12 is a schematic view of a PCR apparatus in example 3;

FIG. 13 is a schematic diagram of a transmissive phosphor module system;

FIG. 14 is a schematic diagram of a reflective fluorescence module system.

Detailed Description

The technical solution will be described clearly and completely with reference to the accompanying drawings in the embodiments, and it is obvious that the described embodiments are only a part of the embodiments, not all of the embodiments. Based on these embodiments, all other embodiments obtained by a person of ordinary skill in the art without any creative effort belong to the protection scope of the patent.

Example 1: PCR instrument

The PCR instrument as shown in FIGS. 1 and 2 comprises a left hot plate 1 and a right hot plate 2 which are opposite to each other, have an electric heating device (not shown) inside, and are heated by the heating device, and a support 3 is arranged between the left hot plate 1 and the right hot plate 2; the bracket 3 is provided with 5 vertical slots 32, and two opposite side walls of the slots are provided with grooves 31. Into each slot 4 PCR tubes 4 are inserted. 4 rows and 5 columns of flat PCR tubes 4 are inserted into the whole rack 3. The bracket 3 is connected with a left-right driving device (belonging to the prior art) 5 which drives the bracket to move left and right; the bracket can move leftwards or rightwards under the drive of the left and right driving device until the coplanar left side surface of each PCR test tube is contacted with the surface of the left hot plate 1 or the coplanar right side surface of each PCR test tube is contacted with the surface of the right hot plate 2.

When the left side surface of each PCR test tube is contacted with the left hot plate, a right air channel 12 is formed between the right side surface of each PCR test tube and the right hot plate, so that the heat insulation between the right side surface of each PCR test tube and the right hot plate is realized; when the right side of each PCR test tube is contacted with the right hot plate, a left air channel 11 is formed between the left side of each PCR test tube and the left hot plate, so that the heat insulation between the left side of each PCR test tube and the left hot plate is realized.

When the left side of the test tube is in contact with the left hot plate, the right air channel 12 can ensure that the temperature of the right hot plate does not have great influence on the temperature of the test tube in contact with the left hot plate; when the test tube right side contacts with the right hot plate, left air passageway 11 can guarantee that the temperature of left hot plate can not cause big influence to the temperature of the test tube with the contact of right hot plate. In order to further reduce the influence of the heat radiation on the test tube by the hot plate which is not in contact with the test tube, air in the air passage may be blown by a blowing device such as a fan, so that a minute amount of air convection is generated in the air passage.

Referring to fig. 3-7, the PCR tube 4 is made of transparent material, and is flat, and includes a tube 41 with an opening 411 at the top and a cap 42 for sealing the opening 411, and the lower part of the left side of the cap is connected to the tube in a flip manner. The middle of the tube cover is provided with an opening plug 421 which protrudes downwards, and when the opening plug 421 extends into the opening 411 on the tube body, the opening can be blocked. Flanges 43 are provided on the outer edges of the left and right sides of the flat test tube, and the thickness of the flanges is smaller than that of the flat test tube. When the PCR tube 4 is mounted on the holder 3, the flanges 43 at both sides thereof are inserted into the grooves 31 of the holder 3, thereby facilitating the mounting or removal of the PCR tube from the holder. This structure, test tube adopt the insertion mode on the support, insert the after-poppet and can stabilize the centre gripping test tube to guarantee that the both sides surface of support all is less than the left and right sides face of test tube, can guarantee like this that the support compresses tightly the left and right sides face of test tube on the surface of two hot plates steadily, make heat transfer that can be good between hot plate and the test tube.

The lower part of the tube body is provided with a tube cavity 44 communicated with the opening.

The left and right sides in the tube body 41 are provided with a left channel 45 and a right channel 46, the lower ends of the two channels are communicated with the tube cavity, but the positions of the lower ends of the two channels communicated with the tube cavity are different. The right channel 46 with a higher position of 461 (a lower port of the right channel) is an air inlet channel, and the left channel with a lower position 451 (a lower port of the left channel) is a return channel 45; the outlet 48 at the upper end of the inlet channel and the inlet 47 at the upper end of the return channel are located on the surface of the body that is in contact with the cap.

A transition passage 49 is arranged in the pipe cover; when the opening plug 421 plugs the opening, the air inlet channel is communicated with the return channel through the transition channel.

The lumen 44 of each PCR tube contains a sample (reaction solution) 100.

When the PCR test tube is used, the tube cover 42 is opened, the sample is added to the test tube by the sample adding gun, the sample (reaction solution) is added into the tube cavity 44 through the opening 411, and at the moment, the left channel 45 and the right channel 46 are communicated with the atmosphere, so that the sample adding to the tube cavity is not blocked due to air compression in the tube cavity. After the sample is added, the liquid level 101 of the sample is higher than the communicating part of the left channel and the tube cavity (the lower port of the left channel)

451 but below the point 461 where the right channel 46 communicates with the lumen (the lower port of the right channel). Then the tube cover is closed, the opening plug 421 blocks the opening, and the left channel 45 and the right channel 46 are communicated with the transition channel 49 to form an internal circulation channel. When the sample is heated and reacted, the evaporated sample enters the air inlet channel from the lower port of the right channel, and flows back to the tube cavity through the transition channel and the backflow channel to form circulation.

Example 2: PCR instrument

Referring to the PCR instrument of embodiment 2 shown in fig. 8 and 9, a fluorescence excitation module 6 and a fluorescence receiving module 7 are added to the PCR instrument of embodiment 1.

The left hot plate 1 and the right hot plate 2 are respectively provided with a light through hole 13 opposite to the lower part of the tube cavity 44 of each PCR test tube 4, each light through hole of the right hot plate 2 is provided with a fluorescence excitation module 6 for emitting excitation light, and each light through hole of the left hot plate 1 is provided with a fluorescence receiving module 7.

Referring to fig. 10 and 11, the fluorescence excitation module 6 belongs to the prior art, and mainly includes an LED light source 61, a collimating lens 62, and an excitation light filter 63; the fluorescence receiving module 7 belongs to the prior art, and mainly comprises a fluorescence filter 71, a collecting lens 72 and a photoelectric sensor 73; the light emitted by the LED light source is emitted as parallel light after passing through the collimating lens, then passes through the light through hole on the right hot plate after passing through the excitation light filter to irradiate the PCR test tube, and the fluorescence emitted by some substances in the reaction solution 100 in the PCR test tube after being excited passes through the light through hole on the left hot plate, then passes through the fluorescence filter and then is converged on the photoelectric sensor through the light collecting lens.

Example 3: PCR instrument

Referring to the PCR instrument of embodiment 3 shown in FIG. 12, the fluorescence excitation module 8 and the fluorescence receiving module 9 are added to the PCR instrument of embodiment 1, and the left hot plate 1 and the right hot plate 2 are made of transparent materials.

A fluorescence excitation module 8 for emitting excitation light is arranged on the left side of the left hot plate, and a fluorescence receiving module 9 is arranged on the right side of the right hot plate.

The fluorescence excitation module 8 comprises a light source 81, a first light collecting mirror 82, a reflective mirror 83, a plurality of excitation light filters 85 which are uniformly distributed on the circumferential direction of a rotating first disc 84 and can transmit different wavelengths, and a second light collecting mirror 86; the fluorescence receiving module 9 comprises a third light collecting mirror 91, fluorescence filters 93 which are uniformly distributed on the circumferential direction of a rotating second disk 92, correspond to different excitation light filters and can transmit different wavelengths, an imaging lens 94 and a camera 95; the first disc and the second disc have the same size and rotate coaxially and synchronously.

The light emitted by the light source is emitted as parallel light after passing through the first light collecting mirror, then is reflected by the reflecting mirror to enter the exciting light filter, and then passes through the second light collecting mirror and irradiates each PCR test tube 4 through the left hot plate; the fluorescence emitted by the excited substances in the reaction solution in each PCR test tube passes through the right hot plate, the third condenser lens and the fluorescence filter, enters the imaging lens and is converged on the target surface of the camera.

Example 4: constant temperature hot plate type second-order rapid PCR instrument

The PCR apparatus shown in example 1, 2 or 3 was used in such a manner that the left hot plate and the right hot plate were kept (constant) at two different reaction temperatures T1 and T2 required for the reaction solution in the PCR tube, respectively; the test tubes are inserted into the support, the left and right driving devices drive the support to move towards the left side, so that the left side surface of each PCR test tube on the support is tightly attached to the left hot plate, after the test tubes are stopped for a preset reaction time, the left and right driving devices drive the support to move towards the right, so that the right side surface of each PCR test tube is tightly attached to the right hot plate, after the test tubes are stopped for a preset reaction time, the left and right driving devices drive the support to move towards the left, so that the left side surface of each PCR test tube is tightly attached to the left hot plate. In this case, the PCR instrument of examples 1 to 3 can be said to be a thermostatic hot plate type second-order rapid PCR instrument.

Example 5: three-order rapid PCR instrument

Another use of the PCR machine of example 1, 2 or 3 comprises the steps of:

1) the left hot plate reaches the first reaction temperature required by the reaction solution in the PCR test tube;

2) moving the support to the left hot plate reaching the first reaction temperature to enable the left side surface of the PCR test tube to be in contact with the left hot plate, staying for a certain reaction time, and simultaneously, starting to change the temperature of the right hot plate to a second reaction temperature required by the reaction solution;

3) then the bracket moves towards the right hot plate reaching the second reaction temperature, so that the right side surface of the PCR test tube is contacted with the right hot plate reaching the second reaction temperature, the reaction time is kept for a certain time, and meanwhile, the left hot plate reaching the first reaction temperature is changed to a third reaction temperature required by the reaction solution;

4) then, moving the bracket to a left hot plate reaching a third reaction temperature, so that the left side surface of the PCR left test tube is contacted with the left hot plate reaching the third reaction temperature, staying for a certain reaction time, and simultaneously, changing the temperature of the right hot plate reaching the second reaction temperature to the first reaction temperature required by the reaction solution;

5) moving the support to the right hot plate reaching the first reaction temperature to enable the right side surface of the PCR test tube to be in contact with the right hot plate reaching the first reaction temperature, staying for a certain reaction time, and simultaneously changing the temperature of the left hot plate reaching the third reaction temperature to a second reaction temperature required by the reaction solution;

6) then the bracket moves towards the left hot plate reaching the second reaction temperature, so that the left side surface of the PCR test tube is contacted with the left hot plate reaching the second reaction temperature, the reaction time is kept for a certain time, and meanwhile, the right hot plate reaching the first reaction temperature is changed to a third reaction temperature required by the reaction solution;

7) moving the support to a right hot plate reaching a third reaction temperature, so that the right side surface of the PCR left test tube is contacted with the right hot plate reaching the third reaction temperature, staying for a certain reaction time, and simultaneously, changing the temperature of the left hot plate reaching the second reaction temperature to the first reaction temperature required by the reaction solution;

and (4) repeating the steps 2) to 7) until the whole PCR reaction is completed.

In this case, the PCR apparatus of examples 1 to 3 can be said to be a three-stage rapid PCR apparatus.

For examples 1-5, the insertion of the holder allows the cuvette to be inserted, i.e. to participate in the reaction, and the PCR apparatus to be in operation at all times. Different tubes may be inserted into the holder at different times, the insertion taking part in the reaction. The operator records or automatically records the insertion time of each test tube through related control software, and displays the reaction state of each test tube on a related display screen, and the state of the test tube for prompting the reaction is set. So to speak, it has the characteristic of plug-and-play reaction and is particularly suitable for emergency treatment.

For examples 1 to 5, the test tube in the form of a sheet has a small lumen volume, and can reduce the reaction system while allowing large-area contact heat transfer.

For the constant-temperature hot plate type second-order rapid PCR instrument in example 4, the two hot plates are in a constant-temperature state, and a temperature raising and lowering process is not required, so that the reaction speed can be greatly increased.

For the third-order rapid PCR instrument of embodiment 5, one hot plate is in contact with the test tube, and when the sample in the test tube reacts, the other hot plate completes the temperature rise or the temperature reduction, that is, the reaction and the temperature rise/reduction can be synchronously overlapped at the same time, thereby saving the reaction time and improving the test speed.

For embodiments 2 to 5, during the heating and reaction processes of the test tubes, the fluorescence excitation module can emit excitation light in real time, the fluorescence receiving module can receive fluorescence in real time, and the real-time detection of the states of the test tubes is realized, so that the real-time fluorescence PCR detector is provided.

For examples 2-5, the thin plate-like tubes, with a larger side area, increased the clear aperture of the reaction sample and improved the sensitivity of real-time fluorescent PCR detection.

For examples 2-5, the system of the transmissive fluorescence module shown in fig. 13 is adopted in this patent, that is, the excitation light emitted by the fluorescence excitation module 6 and the fluorescence excitation module 8 directly penetrates the test tube 4, and the fluorescence emitted after some substances in the test tube are excited penetrates the test tube and is received by the fluorescence receiving module 7 and the fluorescence receiving module 9. Compared with a reflection type fluorescent module system, the transmission type fluorescent module system can obtain larger excitation energy, higher excitation sensitivity and higher signal to noise ratio. Referring to fig. 14, excitation light emitted by the fluorescence excitation module 6 and the fluorescence excitation module 8 enters the test tube 4 through reflection of the spectroscope 14, and fluorescence emitted by some substances in the test tube after being excited passes through the test tube, passes through the spectroscope 14, and is received by the fluorescence receiving module 7 and the fluorescence receiving module 9.

Claims (6)

1. A PCR test tube is characterized in that the whole body is flat and comprises a tube body with an opening at the upper end and a tube cover for plugging the opening, and a tube cavity communicated with the opening is arranged at the lower part in the tube body;

two channels are arranged in the tube body; the lower ends of the two channels are communicated with the tube cavity, but the positions of the lower ends of the two channels communicated with the tube cavity are different;

the channel at the higher position of the position communicated with the tube cavity is an air inlet channel, and the channel at the lower position of the position communicated with the tube cavity is a reflux channel;

the outlet at the upper end of the air inlet channel and the inlet at the upper end of the backflow channel are both positioned on the surface of the pipe body contacted with the pipe cover.

2. The PCR cuvette of claim 1, wherein a transition channel is formed in the cover; when the opening is plugged by the pipe cover, the air inlet channel is communicated with the backflow channel through the transition channel.

3. The PCR cuvette of claim 1, wherein a flange is provided on an outer edge of the flat cuvette, and a thickness of the flange is smaller than that of the flat cuvette.

4. The PCR tube of claim 3, wherein the flanges are located on the left and right sides of the flat tube.

5. The PCR cuvette according to claim 1, wherein a lower portion of one side of the cap is connected to the body in a reversed state.

6. The PCR cuvette according to claim 1, wherein the PCR cuvette is made of a light-transmitting material.

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