CN217868871U - Circulating micro-fluidic PCR chip structure - Google Patents

Abstract

The utility model discloses a circulating microfluidic PCR chip structure, which relates to the technical field of PCR amplification reaction devices and comprises a low-temperature constant-temperature area, a medium-temperature constant-temperature area, a high-temperature constant-temperature area, a circulating flow passage and a circulating power device; the circulating flow channel comprises a first flow channel, a second flow channel and a third flow channel, the first flow channel is arranged in the low-temperature constant-temperature area, the second flow channel is arranged in the medium-temperature constant-temperature area, the third flow channel is arranged in the high-temperature constant-temperature area, one end of the first flow channel is communicated with one end of the second flow channel, the other end of the second flow channel is communicated with one end of the third flow channel, and the other end of the third flow channel is communicated with one end, far away from the second flow channel, of the first flow channel; the circulating power device can be used for driving the materials in the circulating flow channel to circularly flow. The circulating microfluidic PCR chip structure has high space utilization rate, can be universally used for different PCR amplification projects, can accurately control the time of each single cycle and the time of each reaction step in each cycle, and optimizes the reaction effect.

Description

Circulating micro-fluidic PCR chip structure

Technical Field

The utility model relates to a PCR amplification reaction technical field specifically is a circulating micro-fluidic PCR chip structure.

Background

The Polymerase Chain Reaction (PCR) is a molecular biology technique for amplifying specific DNA fragments, and consists of three basic reaction steps of denaturation-annealing-extension: wherein, the denaturation refers to the dissociation of a DNA double strand or a double strand DNA formed by PCR amplification after the template DNA is heated to about 95 ℃ for a certain time so as to make the DNA double strand or the double strand DNA become a single strand; annealing means that the single strand formed in the denaturation process is cooled to about 55 ℃ so that the primer is matched and combined with the complementary sequence of the template DNA single strand; extension refers to the synthesis of a new, semi-preserved, replicated strand complementary to the template DNA strand by the DNA template and primer combination according to the base pairing and semi-preserved replication principles at a specific temperature (typically around 72 ℃). Repeating the three steps of denaturation, annealing and extension to obtain more semi-preserved copy strands, wherein the new strands can become templates for the next cycle, thereby finally realizing the amplification of the DNA fragments.

The micro-fluidic PCR chip is a PCR amplification reaction device for realizing the in-vitro efficient amplification of DNA fragments by completing the circulation steps, the structure of the PCR amplification reaction device generally comprises three constant temperature areas, a micro-channel and the like, the micro-channel is circularly arranged in the three constant temperature areas for many times according to the reaction requirement, and a sample and reaction liquid are injected into an inlet of the micro-channel, circularly pass through the three constant temperature areas when flowing in the micro-channel to complete the circulation process, and are finally discharged from an outlet of the micro-channel.

In the prior art, a microchannel in a microfluidic PCR chip is usually a single channel, that is, a single channel circulates through three constant temperature regions to realize the three basic reaction cycles, and in practical application, the following disadvantages mainly exist:

first, different amplification items differ in the number of cycles in the reaction. The microfluidic PCR chip in the prior art needs to customize the times of the microfluidic PCR chip circulating through three constant temperature reaction areas according to projects, and PCR chips of different projects cannot be used universally. For projects with many requirements on cycle times, the whole volume of the customized microfluidic PCR chip is relatively large, the space utilization rate is low, the design of a constant temperature area is also relatively large and complex, and the constant temperature control of the constant temperature area and the temperature isolation of different constant temperature areas are also relatively difficult.

Secondly, the microfluidic PCR chip in the prior art is in a form that a single microchannel circularly penetrates through three constant temperature areas, the circulating power of the microfluidic PCR chip is from the injection of the inlet of the microchannel, the whole circulating time is determined by the injection power, the precise control of each single circulating time cannot be carried out, and the reaction effect cannot be optimized by controlling the reaction time.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art's is not enough, provides a circulating micro-fluidic PCR chip structure, and it sets up the microchannel respectively in three constant temperature area, and the amplification of DNA fragment is realized to sample and reaction liquid in the mode of microchannel inner loop flow, and it can be general in different PCR amplification projects, and can carry out accurate control to the time of each reaction step in every single cycle time and at every turn circulation, optimizes the reaction effect.

The purpose of the utility model is realized through the following technical scheme:

a circulating microfluidic PCR chip structure comprises a low-temperature constant-temperature area, a medium-temperature constant-temperature area, a high-temperature constant-temperature area, a circulating flow channel and a circulating power device;

the circulating flow channel comprises a first flow channel, a second flow channel and a third flow channel, the first flow channel is arranged in the low-temperature constant-temperature area, the second flow channel is arranged in the medium-temperature constant-temperature area, the third flow channel is arranged in the high-temperature constant-temperature area, one end of the first flow channel is communicated with one end of the second flow channel, the other end of the second flow channel is communicated with one end of the third flow channel, and the other end of the third flow channel is communicated with one end, far away from the second flow channel, of the first flow channel; the circulating power device can be used for driving the materials in the circulating flow channel to circularly flow.

Furthermore, the device also comprises a sample adding channel, an air exhaust channel and a discharge channel; one end of the sample adding channel is communicated with the first flow channel, and a first opening and closing device is arranged on the sample adding channel; one end of the exhaust channel is communicated with the first flow channel, and a second opening and closing device is arranged on the exhaust channel; a third opening and closing device is arranged between the first flow channel and the third flow channel; one end of the discharging channel is communicated with the third flow channel, and a fourth closing device is arranged on the discharging channel; the circulating power device can drive the materials in the circulating flow channel to flow forwards or reversely.

Specifically, the circulating microfluidic PCR chip structure comprises a cover plate and a base plate, wherein a groove is processed at the bottom of the cover plate, and the cover plate is buckled with the base plate to enable the groove to form the circulating flow channel, the sample adding channel, the exhaust channel and the discharge channel.

Furthermore, the first opening and closing device, the second opening and closing device, the third opening and closing device and the fourth opening and closing device all adopt a membrane pump structure.

Furthermore, the chip structure is basically disc-shaped, and further comprises a heat insulation layer, the heat insulation layer equally divides the chip structure into a first sector, a second sector, a third sector and a fourth sector which are sequentially arranged by taking the circle center of the chip structure as the center, the first flow channel is arranged in the first sector, the second flow channel is arranged in the second sector, the third flow channel is arranged in the third sector, and the second opening and closing device, the third opening and closing device and the fourth opening and closing device are all arranged in the fourth sector.

The circulating power device has the following realization forms:

the circulating flow passage is provided with two power holes, the circulating power device adopts an external power device, and the external power device is communicated with the two power holes.

Preferably, the external power device is a peristaltic pump.

Preferably, the two power holes are both arranged between the first flow channel and the third flow channel.

And secondly, the circulating power device is composed of a plurality of membrane pump structures, and the membrane pump structures of the circulating power device are arranged on the circulating flow channel.

Preferably, the circulating power device comprises a fifth membrane pump and a sixth membrane pump, the fifth membrane pump is arranged at a position where the first flow passage is communicated with the second flow passage, and the sixth membrane pump is arranged at a position where the second flow passage is communicated with the third flow passage.

The utility model has the advantages that:

the circulating type microfluidic PCR chip structure is provided with three constant temperature areas, a circulating flow channel and a circulating power device, and materials in the circulating flow channel are driven to circularly flow by the circulating power device during PCR reaction, so that the PCR reaction process is completed by circularly passing through the three constant temperature areas. Compared with the prior art, the liquid is circulated for multiple times through the same circulation flow channel, the space utilization rate is high, the miniaturization of a chip structure is favorably realized, and the constant temperature control is more favorably realized to ensure the reaction effect; meanwhile, the chip has strong structural universality and can be applied to PCR reaction projects with different cycle times and cycle times; and high-precision cycle control can be realized, each single cycle time is accurately controlled, and the reaction effect is optimized by controlling the reaction time.

The circulating type micro-fluidic PCR chip structure can be preheated in a low-temperature constant-temperature area firstly when in use, then enters a high-temperature constant-temperature area to increase the temperature, and then enters a normal circulating process, so that the temperature can be kept stable and excessive, and the reaction effect is improved.

The whole chip structure is made by buckling the cover plate and the base plate, the innovative membrane-pressing pump structure of each opening and closing device is directly made, the whole structure is easy and convenient to manufacture, the integration level is high, the space utilization rate is high, and the requirement of miniaturization of the chip structure is met.

The above-described circulating power plant provides two preferred forms: firstly, a plurality of membrane pump structures are directly arranged on a circulating flow channel, the sequential control of each membrane pump structure is utilized to realize the continuous conveying of materials, the manufacturing is convenient, the integration level is high, the space utilization rate is high, and the device has the advantages of being used in the scene that the external power cannot be arranged due to the narrow space caused by the limitation of equipment; and secondly, two power holes are formed in the circulation flow channel, and a power device such as an external precision peristaltic pump is communicated with the two power holes to provide circulation power, so that the accurate control of the circulation power can be realized, the accurate control of each single circulation time is facilitated, and the reaction effect is optimized through the accurate control of the reaction time.

The circulating type microfluidic PCR chip structure is basically disc-shaped in an overall mode, the overall chip structure is equally divided into four sectors through a heat insulation layer, a low-temperature constant-temperature area, a medium-temperature constant-temperature area and a high-temperature constant-temperature area are arranged in three sectors which are sequentially adjacent, and a power hole and a related opening and closing device are arranged in a fourth sector. According to the arrangement, each constant temperature area can be conveniently separated by the heat insulation layer, so that heat conduction can be effectively reduced, and temperature control of each constant temperature area is facilitated; the opening and closing device, the power hole and the related external power device arranged in the fourth sector cause temperature reduction which is beneficial to the PCR reaction process.

Drawings

FIG. 1 is a schematic view of a flow channel structure in a circulating microfluidic PCR chip structure according to the present invention;

FIG. 2 is a schematic diagram of an embodiment 1 of a structure of a circulating microfluidic PCR chip according to the present invention;

FIG. 3 is a schematic diagram of a cover plate according to embodiment 1 of the present invention;

FIG. 4 is a schematic diagram of a bottom plate in structural example 1 of a circulating microfluidic PCR chip according to the present invention;

FIG. 5 is a schematic structural diagram of a structural example 2 of a circulating microfluidic PCR chip according to the present invention;

FIG. 6 is a schematic diagram of a cover plate according to embodiment 2 of the present invention;

FIG. 7 is a schematic structural diagram of a bottom plate in structural embodiment 2 of a circulating microfluidic PCR chip according to the present invention;

FIG. 8 is a schematic diagram of a membrane pump configuration;

fig. 9 is a schematic diagram of the continuous delivery principle of the membrane pump structure.

In the figure, 1-a low-temperature constant-temperature area, 2-a medium-temperature constant-temperature area, 3-a high-temperature constant-temperature area, 4-a first flow channel, 5-a second flow channel, 6-a third flow channel, 7-a sample adding channel, 8-an exhaust channel, 9-a discharge channel, 10-a first opening and closing device, 11-a second opening and closing device, 12-a third opening and closing device, 13-a fourth opening and closing device, 14-a cover plate, 15-a base plate, 16-a membrane, 17-a fifth membrane pump, 18-a sixth membrane pump, 19-an external power device, 20-a power hole and 21-a heat insulation layer.

Detailed Description

The technical solution of the present invention is described in further detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following description.

As shown in FIG. 1, a structure of a circulating microfluidic PCR chip comprises a low-temperature constant-temperature region 1, a medium-temperature constant-temperature region 2, a high-temperature constant-temperature region 3, a circulating flow channel and a circulating power device.

The three constant temperature regions respectively correspond to three basic reaction steps of 'denaturation-annealing-extension' of PCR, wherein the set temperature of the low-temperature constant temperature region 1 is 45-55 ℃, the set temperature of the medium-temperature constant temperature region 2 is about 72 ℃, and the set temperature of the high-temperature constant temperature region 3 is about 95 ℃. The circulating flow channel comprises a first flow channel 4, a second flow channel 5 and a third flow channel 6, the first flow channel 4 is arranged in the low-temperature constant-temperature area 1, the second flow channel 5 is arranged in the medium-temperature constant-temperature area 2, the third flow channel 6 is arranged in the high-temperature constant-temperature area 3, one end of the first flow channel 4 is communicated with one end of the second flow channel 5, the other end of the second flow channel 5 is communicated with one end of the third flow channel 6, and the other end of the third flow channel 6 is communicated with one end, far away from the second flow channel 5, of the first flow channel 4. The circulating power device can be used for driving the materials in the circulating flow channel to circularly flow.

After a sample and reaction liquid are injected into the circulating flow channel, the circulating flow power device can drive the circulating flow channel to circularly flow in the direction of 'a first flow channel 4-a second flow channel 5-a third flow channel 6-a first flow channel 4 \8230 \ 8230;' and circularly complete three reaction steps of 'denaturation-annealing-extension' in three constant temperature areas, so that the amplification of DNA fragments is realized.

In the PCR amplification project, different projects require different cycles depending on the single cycle time. For example, the shortest single cycle time of pathogenic vibrio, food-borne pathogenic bacteria, diarrheagenic microorganisms (bacteria), diarrheagenic colon typing is 60 seconds, while the longest single cycle time of diarrheagenic microorganisms (viruses), instant fruits and vegetables, genital tract pathogenic bacteria is 90 seconds; the minimum cycle times of pathogenic vibrios, food-borne pathogenic bacteria, diarrheagenic microorganisms (bacteria), 11 animal-derived, non-prepackaged foods, food-borne plant allergens and transgenes (soybean, rice, corn and rape) are 30, and the maximum cycle times of the genital tract pathogenic bacteria are 40. The single channel adopted by the microfluidic PCR chip in the prior art circularly passes through the three constant temperature areas, the number of the circulating times which can be realized is determined at the beginning of the design, and the existing PCR chip cannot be used universally for items with different circulating times requirements, and needs to be customized in production practice. Particularly for items with more requirements on cycle times, the micro-channel needs to pass through each constant temperature area more times, so that the whole volume of the whole micro-fluidic PCR chip is increased, the space utilization rate is low, and pain points exist on the structural design of the miniature chip all the time. Meanwhile, the constant temperature area of the large chip structure is relatively large and complex in design, constant temperature control of the constant temperature area and temperature isolation of different constant temperature areas are relatively difficult, and adverse effects are often caused on reaction effects. In practical application, the temperature of each constant temperature region often fluctuates in a certain range to affect the reaction effect, because the microfluidic PCR chip in the prior art is usually in a form that a single microchannel circularly passes through three constant temperature regions, the circulating power of the microfluidic PCR chip is from the injection of the inlet of the microchannel, the circulating time is determined by the injection power, the single circulating time tends to be the same (if the circulating time is adjusted by changing the injection power, the influence on each section of material in the microchannel is caused), the single circulating time cannot be accurately controlled independently, and the reaction effect cannot be optimized by the accurate control of the reaction time.

In the structure of the circulating microfluidic PCR chip, the reaction process is driven by the circulating power device, so that materials circularly flow in the same circulating flow channel, the structure is simple and compact, the space utilization rate is high, and the miniaturization design requirement is met; the circulation times and the single circulation time can be freely selected according to the requirements, the method can be suitable for projects with different circulation times and circulation speeds, and the universality is strong; and each circulation time can be independently controlled, the temperature fluctuation of the constant temperature area can be compensated through the control of the reaction time, and the reaction effect is optimized.

Furthermore, the structure of the circulating microfluidic PCR chip also comprises a sample adding channel 7, an exhaust channel 8 and a discharge channel 9; one end of the sample adding channel 7 is communicated with the first flow channel 4, and a first opening and closing device 10 is arranged on the sample adding channel 7; one end of the exhaust passage 8 is communicated with the first flow passage 4, and the exhaust passage 8 is provided with a second opening and closing device 11; a third opening and closing device 12 is arranged between the first flow passage 4 and the third flow passage 6; one end of the discharging channel 9 is communicated with the third flow channel 6, and a fourth closing device 13 is arranged on the discharging channel 9; the circulating power device can drive the materials in the circulating flow channel to flow forwards or reversely.

When in use, the circulating microfluidic PCR chip structure is carried out according to the following steps:

s1, opening the first opening and closing device 10 and the fourth opening and closing device 13, pushing the sample and the multiple PCR reaction solution into the first flow channel 4 by using an instrument pipeline and a liquid transfer arm (air in the circulating flow channel is discharged through the discharge channel 9 and the fourth opening and closing device 13 after sample adding is finished). The sample and the multiplex PCR reaction solution were preheated in the low-temperature constant-temperature region 1.

S2, opening the third opening and closing device 12, starting the circulating power device to make the circulating power device move reversely, driving the sample and the multiple PCR reaction liquid to enter the third flow channel 6 in the high-temperature constant-temperature area 3, and waiting for a specific time; then the circulating power device moves forward to drive the liquid in the circulating flow channel to circularly flow in the directions of 'a first flow channel 4, a second flow channel 5, a third flow channel 6 and the first flow channel 4', 8230. After completing the PCR reaction for a certain number of cycles, the third opening and closing means 12 and the cycling power means are closed.

And S3, opening the fourth opening and closing device 13 and the second opening and closing device 11, opening the circulating power device, and driving the reacted liquid in the circulating flow channel to be discharged through the discharge channel 9 (in the liquid discharging process, outside air enters the circulating flow channel through the second opening and closing device 11 and the exhaust channel 8).

In the prior art, the circulation process is usually directly carried out, the circulation process is generally carried out from a low-temperature constant-temperature area 1, the temperature required by the reaction is difficult to be quickly reached by external materials at the initial stage of entering, and if the circulation process is directly carried out from other constant-temperature areas, a quick temperature rise process exists, so that the reaction is unfavorable. The utility model discloses a circulating micro-fluidic PCR chip structure can be preheated through low temperature constant temperature district 1 earlier when using, and 3 lifting temperature in reentrant high temperature constant temperature district, reentrant normal cycle process thereafter is favorable to keeping the temperature steady excessive, promotes the reaction effect.

In specific implementation, as shown in fig. 2-7, the structure of the circulating microfluidic PCR chip includes a cover plate 14 and a substrate 15, a groove is formed in the bottom of the cover plate 14, the shape of the groove corresponds to the shape of the circulating flow channel, the sample loading channel 7, the exhaust channel 8 and the discharge channel 9, and after the cover plate 14 is fastened to the substrate 15, the groove directly forms the circulating flow channel, the sample loading channel 7, the exhaust channel 8 and the discharge channel 9, which is relatively convenient in the manufacturing process.

The first opening/closing device 10, the second opening/closing device 11, the third opening/closing device 12, and the fourth opening/closing device 13 may be any device structure capable of switching the on/off state of the passage. In this embodiment, each of the opening/closing devices is of a membrane pump structure.

The membrane pump structure utilizes the positive and negative pressure switching of the membrane to realize the disconnection and connection of the channel, and the structure is shown in fig. 8. At the position of the membrane pump structure, the groove on the cover plate 14 is processed into a disconnected state, a through hole is processed on the base plate 15 at the position corresponding to the groove in the disconnected state, and a membrane 16 is arranged between the cover plate 14 and the base plate 15 when the cover plate and the base plate are buckled. When positive pressure is applied to the membrane 16 through the through holes (for example, air is inflated to the membrane direction through the through holes), the middle part of the membrane 16 is pressed against the bottom surface of the cover plate 14, and the channel formed by the grooves on the cover plate 14 is in a disconnected state; when negative pressure is applied to the membrane 16 through the through hole (for example, the membrane is sucked through the through hole), the middle part of the membrane 16 is sucked toward the through hole, so that a gap is formed between the middle part of the top surface of the membrane 16 and the bottom surface of the cover plate 14, and the broken groove on the cover plate 14 is communicated through the gap.

In this embodiment, the first opening/closing device 10, the second opening/closing device 11, the third opening/closing device 12, and the fourth opening/closing device 13 are all directly fabricated according to the above-mentioned membrane pump structure, that is, the groove on the cover plate 14 is cut off at the corresponding position, the base plate 15 is provided with a through hole, and the membrane 16 is disposed between the cover plate 14 and the base plate 15 at the corresponding position. The opening and closing device is directly formed in the above mode, the whole manufacturing process is simple and convenient, the opening and closing device does not need to be additionally configured, and the space utilization rate is improved. Meanwhile, the membrane pump is consistent in structure, a suction device (such as a cylinder piston type suction cylinder) can be arranged outside the membrane pump, the pipeline with the control valve is communicated with the through holes of the substrate 15 respectively, each opening and closing device is controlled, the integrated characteristic is embodied, automatic control is realized, and the whole control process is relatively simple and convenient.

The circulating power device can be selected from various structural forms, and two preferable implementation modes are provided in the embodiment:

example 1, as shown in fig. 2-4:

the circulating power device is composed of a plurality of membrane pump structures, the membrane pump structures of the circulating power device are all arranged on the circulating flow channel, continuous transportation of fluid in two directions can be realized through matching control of the membrane pumps, and the principle of the circulating power device is shown in fig. 9. The diagrams a-f are schematic states of the three membrane pumps in continuous transportation, arrows indicate the conditions that the three membrane pumps are subjected to positive pressure or negative pressure (the arrows are upward positive pressure and downward negative pressure), and the shading is the position of the material in the flow channel. As can be seen from the figure, when the positive pressure or negative pressure state of each membrane pump is controlled in sequence, the continuous conveying of the materials in the flow channel can be realized.

The circulation power device is directly manufactured by the membrane pump structure, has the advantages of simple and convenient manufacture, does not need to be externally connected with other power equipment, simultaneously, each membrane pump structure for continuous conveying in the circulation power device can also adopt a suction device to directly realize automatic control according to the mode, has high integration level and high space utilization rate, and has particular advantages in use under the scene that external power cannot be set due to the limitation of equipment and the narrow space.

In specific implementation, in order to avoid the influence of a membrane pump structure serving as a circulating power device on temperature control of a constant temperature area, the circulating power device comprises a fifth membrane pump 17 and a sixth membrane pump 18, the fifth membrane pump 17 is arranged at a position where the first flow passage is communicated with the second flow passage, and the sixth membrane pump 18 is arranged at a position where the second flow passage is communicated with the third flow passage. In this case, the membrane pump structure of the third opening/closing device 12 also participates in providing the circulating power, and the three components form a three-membrane pump structure as shown in fig. 9.

Example 2, as shown in fig. 5-7:

the circulating power device is an external power device 19. At this time, two power holes 20 are formed in the circulating flow channel, the external power device 19 is communicated with the two power holes 20, and the external power device 19 extracts materials in the circulating flow channel from one power hole 20 and discharges the materials into the circulating flow channel from the other power hole 20, so that circulating power is provided. In theory, any device with the above functions can be selected as the external power device 19, and in this embodiment, the external power device 19 is a peristaltic pump which operates continuously and can provide continuous circulating power. The optimized precise peristaltic pump can realize precise control of circulating power, is beneficial to precisely controlling each single circulating time, and optimizes the reaction effect through precise control of the reaction time.

In specific implementation, the two power holes 20 are both arranged between the first flow channel 4 and the third flow channel 6, power is pumped from the third flow channel 6 to the first flow channel 4 in a circulating reaction, when the reaction process shows that the material enters the low-temperature constant-temperature area 1 from the high-temperature constant-temperature area 3, the material belongs to a cooling process, the power holes 20 are arranged at the position, and the temperature reduction of the material caused by the external power device 19 does not cause adverse effects on a PCR process, but is beneficial to the PCR circulating process.

Furthermore, in the specific implementation, the whole structure of the circulating microfluidic PCR chip is basically disc-shaped, the whole structure is sealed on the reaction temperature control part of the instrument when the circulating microfluidic PCR chip is applied, and the upper surface and the lower surface of the circulating microfluidic PCR chip are both provided with high-efficiency constant-temperature-control metal conductors for forming each constant-temperature area. The heat insulation structure comprises a heat insulation layer 21, wherein the heat insulation layer 21 equally divides the whole chip structure into a first sector, a second sector, a third sector and a fourth sector which are sequentially arranged by taking the circle center as the center, a first flow channel 4 is arranged in the first sector, a second flow channel 5 is arranged in the second sector, a third flow channel 6 is arranged in the third sector, and a second opening and closing device 11, a third opening and closing device 12 and a fourth opening and closing device 13 are all arranged in the fourth sector. The first sector, the second sector and the third sector respectively correspond to the low-temperature constant-temperature area 1, the medium-temperature constant-temperature area 2 and the high-temperature constant-temperature area 3, the sectors are arranged in a mode that each constant-temperature area can be conveniently separated through the heat insulation layer 21, and meanwhile, the characteristics of PCR reaction are fully considered when the constant-temperature areas are separated, so that the constant-temperature areas with close temperatures are separated through the heat insulation layer 21, and the fourth sector is arranged between the low-temperature constant-temperature area 1 with large temperature difference and the high-temperature constant-temperature area 3 except the heat insulation layer 21 for isolation. Therefore, the heat conduction can be effectively reduced, and the temperature control of each constant temperature area is facilitated.

The foregoing is illustrative of the preferred embodiments of the present invention, and it is to be understood that the invention is not limited to the precise forms disclosed herein and that the invention is not to be considered as limited to the disclosed embodiments, but is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. But that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. A circulating microfluidic PCR chip structure comprises a low-temperature constant-temperature area, a medium-temperature constant-temperature area and a high-temperature constant-temperature area, and is characterized by also comprising a circulating flow channel and a circulating power device;

the circulating flow channel comprises a first flow channel, a second flow channel and a third flow channel, the first flow channel is arranged in the low-temperature constant-temperature area, the second flow channel is arranged in the medium-temperature constant-temperature area, the third flow channel is arranged in the high-temperature constant-temperature area, one end of the first flow channel is communicated with one end of the second flow channel, the other end of the second flow channel is communicated with one end of the third flow channel, and the other end of the third flow channel is communicated with one end, far away from the second flow channel, of the first flow channel; the circulating power device can be used for driving the materials in the circulating flow channel to circularly flow.

2. The structure of the circulating microfluidic PCR chip of claim 1, further comprising a sample loading channel, an exhaust channel and a discharge channel;

one end of the sample adding channel is communicated with the first flow channel, and a first opening and closing device is arranged on the sample adding channel;

one end of the exhaust channel is communicated with the first flow channel, and a second opening and closing device is arranged on the exhaust channel;

a third opening and closing device is arranged between the first flow channel and the third flow channel;

one end of the discharging channel is communicated with the third flow channel, and a fourth closing device is arranged on the discharging channel;

the circulating power device can drive the materials in the circulating flow channel to flow forwards or reversely.

3. The structure of claim 2, comprising a cover plate and a substrate, wherein the bottom of the cover plate is provided with a groove, and the cover plate is fastened to the substrate to form the groove into the circulating channel, the sample loading channel, the exhaust channel and the discharge channel.

4. A circulating microfluidic PCR chip structure according to claim 3, wherein the first, second, third and fourth opening/closing devices are membrane pump structures.

5. A circulating microfluidic PCR chip structure according to any of claims 2-4, wherein the chip structure is substantially disc-shaped, further comprising a thermal insulation layer, the thermal insulation layer equally divides the chip structure into a first sector, a second sector, a third sector and a fourth sector which are sequentially arranged around the center of the circle, the first flow channel is disposed in the first sector, the second flow channel is disposed in the second sector, the third flow channel is disposed in the third sector, and the second, third and fourth opening/closing devices are disposed in the fourth sector.

6. The structure of a circulating microfluidic PCR chip according to any one of claims 1-4, wherein the circulating flow channel is provided with two power holes, the circulating power device is an external power device, and the external power device is communicated with both of the two power holes.

7. The structure of the cycling microfluidic PCR chip of claim 6, wherein the external power device is a peristaltic pump.

8. The structure of the circulating microfluidic PCR chip of claim 6, wherein the two power holes are disposed between the first flow channel and the third flow channel.

9. The structure of any one of claims 1 to 4, wherein the cycling power device comprises a plurality of membrane pump structures, and the membrane pump structures of the cycling power device are all disposed on the cycling flow channel.

10. The structure of a circulating microfluidic PCR chip according to claim 9, wherein the circulating power device comprises a fifth membrane pump and a sixth membrane pump, the fifth membrane pump is disposed at a position where the first flow channel is communicated with the second flow channel, and the sixth membrane pump is disposed at a position where the second flow channel is communicated with the third flow channel.

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