Handheld convection PCR instrument

Abstract

The utility model discloses a handheld convection PCR instrument which comprises a shell, a constant-temperature heating module, a charging module, a power supply module, a touch screen module, a mainboard module, a fan, a cover body and a laminate, the charging module is connected with the power supply module, and the constant-temperature heating module, the power supply module and the touch screen module are respectively connected with the mainboard module; the power module is arranged at the bottom of the shell, the mainboard module is arranged above the power module and fixed in the shell, the laminate is fixed in the shell, the constant-temperature heating module is embedded in the laminate and fixed in the shell, the convection tube is inserted into the constant-temperature heating module, and the fan is installed on the laminate and located on one side of the constant-temperature heating module. The cover body is installed on the shell and located over the constant-temperature heating module. The constant-temperature heating module comprises two layers, the upper-layer constant-temperature heating module is sequentially provided with an annealing aluminum block, a heating piece, a temperature sensor and an extending aluminum block from top to bottom, and the lower-layer constant-temperature heating module is sequentially provided with a modified aluminum block, a heating piece, a temperature sensor and a polytetrafluoroethylene base plate from top to bottom.

Description

Technical Field

[0001] The utility model relates to the technical field of molecular diagnosis, and particularly to a handheld convection PCR instrument for nucleic acid amplification. Background Art

[0002] Polymerase chain reaction (PCR) is a nucleic acid synthesis technology that utilizes the principle of DNA double-strand replication to replicate specific DNA fragments in vitro. Traditional polymerase chain reaction technology needs to go through three stages: DNA denaturation, annealing, and extension. Each stage corresponds to a different temperature, usually requiring about 30 cycles, with a duration of 2 - 3 hours or longer. The process is time-consuming and the equipment is large.

[0003] Existing convection PCR instruments usually rely on the principle of thermal convection to cause thermal convection inside the capillary, stratifying the reaction into three stable temperature regions of denaturation, annealing, and extension, and completing the PCR process in a very short time to achieve DNA amplification. Convection PCR technology solves the problem of the long duration of the traditional PCR process. However, general convection PCR instruments are large in volume and high in cost. They need to be plugged in for use and are not easy to be taken outdoors for independent use. The operation is complex and requires trained operators. The thermal convection region is easily interfered by the outside world, resulting in uneven temperature and low temperature control accuracy. Summary of the Invention

[0004] The purpose of the utility model is to solve the problems of the existing convection PCR instrument, such as large volume, high cost, not easy to carry, complex operation, low heating efficiency, and uneven heating, and to provide a handheld convection PCR instrument with a simple structure, a concise operation interface, simple and convenient operation, which is conducive to large-scale application.

[0005] In order to achieve the above purpose, the technical solutions adopted by the utility model are as follows:

[0006] A handheld convection PCR instrument includes a housing, a constant temperature heating module, a charging module, a power supply module, a touch screen module, a main board module, a fan, a cover body, and a layer board. The charging module is connected to the power supply module, and the constant temperature heating module, the power supply module, and the touch screen module are respectively connected to the main board module;

[0007] The power supply module is arranged at the bottom of the housing. The main board module is arranged above the power supply module and fixed inside the housing. The layer board is fixed inside the housing. The constant temperature heating module is embedded in the layer board and fixed inside the housing. The convection tube is inserted into the constant temperature heating module. The fan is installed on the layer board and located on one side of the constant temperature heating module. The cover body is installed on the housing and located directly above the constant temperature heating module;

[0008] The constant temperature heating module includes an upper constant temperature heating module and a lower constant temperature heating module. The upper constant temperature heating module is sequentially provided with a constant temperature annealing aluminum block, an upper ceramic heating sheet, an upper temperature sensor, and a constant temperature extension aluminum block from top to bottom. The lower constant temperature heating module is sequentially provided with a constant temperature denaturation aluminum block, a lower ceramic heating sheet, a lower temperature sensor, and a PTFE backing plate from top to bottom.

[0009] Further, the upper constant temperature heating module and the lower constant temperature heating module are fixedly connected by a plurality of double-pass nylon studs. The height of the double-pass nylon studs is preferably 4 mm, and the shape of the double-pass nylon studs is preferably hexagonal.

[0010] Further, the charging module is provided with a USB Type-C interface. The charging module is used to convert the DC 5V voltage input by an external USB Type-C charger into a DC 12V voltage and supply it to the power module.

[0011] Further, the power module includes a DC 12V lithium battery. The charging input voltage and the discharging output voltage of the power module are both DC 12V. The power module is charged through the charging module.

[0012] Further, the touch screen module is a serial screen. The touch screen module communicates with the main board module through the USART protocol.

[0013] Further, the main board module is provided with a chip control circuit, a buck circuit, a serial communication circuit, a temperature acquisition circuit, a heating drive circuit, a fan control circuit, an input voltage protection circuit, a reset circuit, and a program debugging circuit. The buck circuit, the serial communication circuit, the temperature acquisition circuit, the heating drive circuit, the fan control circuit, the input voltage protection circuit, the reset circuit, and the program debugging circuit are respectively connected to the chip control circuit;

[0014] The serial communication circuit, the temperature acquisition circuit, the input voltage protection circuit, and the program debugging circuit are respectively connected to the buck circuit. The touch screen module is connected to the serial communication circuit. The upper temperature sensor and the lower temperature sensor are respectively connected to the temperature acquisition circuit. The upper ceramic heating sheet and the lower ceramic heating sheet are respectively connected to the heating drive circuit. The fan is connected to the fan control circuit. The power module is connected to the input voltage protection circuit.

[0015] Further, it further includes an air inlet and an air outlet. The air inlet is of a blade structure, and the air outlet is of a louver structure. The air inlet and the air outlet are embedded in the housing. The air inlet is arranged directly above the fan, and the air outlet is arranged at a 45-degree angle directly in front of the fan.

[0016] Further, the cover body includes a lid and a guide rail. The lid reciprocates on the guide rail to open and close the lid.

[0017] Furthermore, the layer plate includes a polytetrafluoroethylene partition plate and an aluminum plate, the aluminum plate is covered on the polytetrafluoroethylene partition plate, and the aluminum plate and the polytetrafluoroethylene partition plate are arranged opposite to each other.

[0018] Furthermore, the thickness of the aluminum plate is preferably 2 mm, and the thickness of the polytetrafluoroethylene separator is preferably 2 mm.

[0019] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0020] 1. The utility model adopts a ceramic heating plate and a thermistor sensor, which has the advantages of small size, high heating efficiency, and good sensing accuracy, and effectively overcomes the defects of uneven heating and inaccurate temperature reading of the traditional PCR instrument heating rod.

[0021] 2. In a traditional convection PCR instrument, the lower constant temperature heating module and the upper constant temperature heating module are connected by screws with high thermal conductivity, and the temperature of the lower constant temperature heating module has a greater influence on the temperature of the upper constant temperature heating module.

[0022] The utility model adopts a heat-insulating double-pass nylon stud connection between two constant temperature heating modules to separate the upper constant temperature heating module and the lower constant temperature heating module, thereby reducing the influence of the lower constant temperature heating module on the upper constant temperature heating module.

[0023] 3. The utility model is compact in size and has a built-in removable large-capacity lithium battery. It is charged using a USB Type-C charging head and can be used continuously for about 7 hours when fully charged. Compared with traditional PCR instruments, it has more application scenarios.

[0024] The utility model does not need to be connected to a computer, a mobile phone or other equipment, can be operated independently, does not require an expensive temperature-changing device, greatly reduces the instrument cost, has a simple instrument structure, and is easy to mass produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The utility model is a cross-sectional schematic diagram of a handheld convection PCR instrument.

[0026] Figure 2 This is a schematic diagram of the structure after the shell is visualized.

[0027] Figure 3 It is a schematic diagram of the combination of the constant temperature heating module.

[0028] Figure 4 It is a cross-sectional schematic diagram of the constant temperature heating module.

[0029] Figure 5 This is a schematic diagram of the decomposition of the constant temperature heating module.

[0030] Figure 6 It is a schematic diagram of the combination of the convection tube and the constant temperature heating module.

[0031] Figure 7 It is a three-dimensional schematic diagram of the charging module.

[0032] Figure 8 It is a three-dimensional schematic diagram of the power supply module.

[0033] Figure 9 It is a three-dimensional schematic diagram of the touch screen module.

[0034] Figure 10 It is a three-dimensional schematic diagram of the main board module.

[0035] Figure 11 It is the circuit diagram of the main board module.

[0036] Figure 12 It is a three-dimensional schematic diagram of the fan.

[0037] Figure 13 It is a three-dimensional schematic diagram of the laminate.

[0038] Figure 14 It is a three-dimensional schematic diagram of the button.

[0039] Figure 15 It is the gel electrophoresis diagram of the convection PCR amplification effect.

[0040] Explanation of the reference numerals in the attached drawings:

[0041] 1 - housing; 2 - constant temperature heating module; 21 - upper constant temperature heating module; 211 - constant temperature annealing aluminum block; 212 - upper ceramic heating sheet; 213 - upper temperature sensor; 214 - constant temperature extension aluminum block; 22 - lower constant temperature heating module; 221 - constant temperature denaturation aluminum block; 222 - lower ceramic heating sheet; 223 - lower temperature sensor; 224 - PTFE backing plate; 23 - double - through nylon hexagon stud; 3 - charging module; 4 - power supply module; 5 - touch screen module; 501 - display screen; 502 - serial port pin; 503 - touch screen positioning hole;

[0042] 6 - main board module; 601 - chip control circuit; 6011 - main control chip; 602 - buck circuit; 603 - serial port communication circuit; 6031 - communication power supply socket; 604 - temperature acquisition circuit; 6041 - first input socket; 6042 - second input socket; 605 - heating drive circuit; 6051 - first output terminal; 6052 - second output terminal; 606 - fan control circuit; 6061 - fan output terminal; 607 - input voltage protection circuit; 6071 - main board switch; 6072 - external input terminal; 608 - reset circuit; 6081 - reset switch; 609 - program debugging circuit; 6091 - program download terminal;

[0043] 7 - Air inlet; 8 - Fan; 9 - Air outlet; 10 - Cover body; 101 - Lid; 102 - Guide rail; 103 - Spacer; 104 - Button fixing hole; 105 - Charging module fixing hole; 106 - Heating module fixing part; 107 - Wire outlet hole; 108 - Limiting plate; 109 - Fixed backing plate; 110 - Touch screen fixing hole; 11 - Laminate; 1101 - Laminate positioning hole; 1102 - Teflon partition; 1103 - Aluminum plate; 1104 - Embedded hole; 12 - Button. Detailed implementation mode

[0044] The following further describes a handheld convection PCR instrument of the present utility model in conjunction with the accompanying drawings and specific embodiments.

[0045] Please refer to Figure 1 , the present utility model discloses a handheld convection PCR instrument, including a housing 1, a constant temperature heating module 2, a charging module 3, a power supply module 4, a touch screen module 5, a main board module 6, an air inlet 7, a fan 8, an air outlet 9, a cover body 10, a laminate 11 and a button 12. The charging module 3 is connected to the power supply module 4, and the constant temperature heating module 2, the power supply module 4 and the touch screen module 5 are respectively connected to the main board module 6.

[0046] Please refer to Figure 1 and Figure 2 , the charging module 3, the touch screen module 5, the cover body 10 and the button 12 are installed on the housing 1, and the constant temperature heating module 2, the power supply module 4, the main board module 6, the fan 8 and the laminate 11 are installed inside the housing 1. The charging module 3 is fixed in the charging module fixing hole 105 on the housing 1. The power supply module 4 is arranged at the bottom of the housing 1 and fixed by the limiting plate 108. The power supply module 4 is connected to the charging module 3 through a wire. The main board module 6 is arranged above the power supply module 4 and fixed inside the housing 1 by the fixed backing plate 109.

[0047] The laminate 11 is fixed inside the housing 1. The constant temperature heating module 2 is embedded in the laminate 11, and the convection tube is inserted into the constant temperature heating module 2. The fan 8 is installed on the laminate 11 and located on one side of the constant temperature heating module 2. The cover body 10 is located directly above the constant temperature heating module 2. The cover body 10 includes a lid 101 and a guide rail 102. The lid 101 reciprocates on the guide rail 102 to achieve the purpose of opening and closing the lid 101. The button 12 is fixed in the button fixing hole 104 of the housing 1, as Figure 1 and Figure 14 shown.

[0048] Please refer to Figure 3 , Figure 4 and Figure 5, the constant temperature heating module 2 includes an upper constant temperature heating module 21 and a lower constant temperature heating module 22. The upper constant temperature heating module 21 is provided with a constant temperature annealing aluminum block 211, an upper ceramic heating sheet 212, an upper temperature sensor 213, and a constant temperature extension aluminum block 214 from top to bottom in sequence. The lower constant temperature heating module is provided with a constant temperature denaturation aluminum block 221, a lower ceramic heating sheet 222, a lower temperature sensor 223, and a PTFE backing plate 224 from top to bottom in sequence.

[0049] The top of the upper constant temperature heating module 21 is embedded in the embedding hole 1104 of the layer board 11. The leads of the upper ceramic heating sheet 212, the upper temperature sensor 213, the lower ceramic heating sheet 222, the lower temperature sensor 223, and the fan 8 are connected from the wire outlet hole 107 in the housing 1 to the main board module 6. The lower constant temperature heating module 22 is fixed in the housing 1 through a heating module fixing part 106.

[0050] As Figure 3 shown, the upper constant temperature heating module 21 and the lower constant temperature heating module 22 are connected by four double-pass nylon hexagon studs 23 in the middle. The height of the double-pass nylon stud 23 is preferably 4 mm, and the shape is preferably hexagonal. The screws in the double-pass nylon hexagon stud 23 do not touch each other, and there is an air chamber in the middle, effectively reducing the influence of the high temperature of the lower layer on the low temperature of the upper layer. The convection tube is inserted into the constant temperature heating module 2, and the upper constant temperature heating module 21 and the lower constant temperature heating module 22 are used to realize the heat convection of the fluid therein, meeting the temperature requirements for DNA denaturation, annealing, and extension, and finally achieving the purpose of amplification.

[0051] Please refer to Figure 4 and Figure 5 , circular holes of different sizes are opened in the exact middle of the constant temperature annealing aluminum block 211, the upper ceramic heating sheet 212, the upper temperature sensor 213, the constant temperature extension aluminum block 214, the constant temperature denaturation aluminum block 221, the lower ceramic heating sheet 222, and the lower temperature sensor 223 for inserting the convection tube. The working position of the convection tube inserted into the constant temperature heating module 2 is as Figure 6 shown.

[0052] Preferably, the inner diameter of the upper hole of the constant temperature annealing aluminum block 211 is 2.55 mm, the inner diameter of the lower hole is 2.45 mm, the outer diameter of the lower hole is 2.84 mm, and the depth is 2 mm. The inner diameter of the hole of the constant temperature extension aluminum block 214 is 8 mm, and the depth is 4 mm. The inner diameter of the upper hole of the constant temperature denaturation aluminum block 221 is 1.58 mm, the inner diameter of the lower hole is 1.76 mm, and the depth is 2.1 mm. The inner diameter of the hole inside the upper ceramic heating sheet 212 and the lower ceramic heating sheet 222 is 3 mm. The inner diameter of the hole inside the upper temperature sensor 213 and the lower temperature sensor 223 is 8 mm.

[0053] As Figure 7 and Figure 8As shown, the charging module 3 is provided with a USB Type-C interface. The charging module 3 is used to convert the DC 5V voltage input by an external USB Type-C charger into a DC 12V voltage and supply it to the power module 4. The power module 4 and the charging module 3 are connected by wires. The power module 4 includes a DC 12V lithium battery. The charging input voltage and the discharging output voltage of the power module 4 are both DC 12V. The power module 4 is charged through the charging module 3.

[0054] When there is an external input to the power module 4, the gate G of the semiconductor field effect transistor conducts, and the P-channel semiconductor field effect transistor cuts off. The external input supplies power to both the main board module 6 and the power module 4 simultaneously. At this time, no current passes through the main board module 6 in the power module 4. When there is no external input to the power module 4, the gate G of the semiconductor field effect transistor closes, and the P-channel semiconductor field effect transistor turns on. The power module 4 supplies power to the main board module 6.

[0055] As Figure 9 shown, the touch screen module 5 is a serial screen and is fixed in the touch screen fixing hole 110 at the top of the housing 1 with M3.5*4 screws through the touch screen positioning hole 503 on the touch screen module 5. The touch screen module 5 is connected to the main board module 6 through the serial port pin 502 and communicates with the main board module 6 through the USART protocol. The touch screen module 5 is used to set the temperatures and heating times of the upper layer constant temperature heating module 21 and the lower layer constant temperature heating module 22, and generate a temperature curve in real time by receiving the temperatures of the upper layer temperature sensor 213 and the lower layer temperature sensor 223 read by the main board module 6. The display screen 501 of the touch screen module 5 also has interactive functions such as a user manual, brightness adjustment, and event reminder.

[0056] As Figure 10 and Figure 11 shown, the main board module 6 is provided with a chip control circuit 601, a buck circuit 602, a serial communication circuit 603, a temperature acquisition circuit 604, a heating drive circuit 605, a fan control circuit 606, an input voltage protection circuit 607, a reset circuit 608, and a program debugging circuit 609. The buck circuit 602, the serial communication circuit 603, the temperature acquisition circuit 604, the heating drive circuit 605, the fan control circuit 606, the input voltage protection circuit 607, the reset circuit 608, and the program debugging circuit 609 are respectively connected to the chip control circuit 601.

[0057] The serial communication circuit 603, the temperature acquisition circuit 604, the input voltage protection circuit 607, and the program debugging circuit 609 are respectively connected to the buck circuit 602. The touch screen module 5 is connected to the serial communication circuit 603. The upper temperature sensor 213 and the lower temperature sensor 223 are respectively connected to the temperature acquisition circuit 604. The upper ceramic heating sheet 212 and the lower ceramic heating sheet 222 are respectively connected to the heating drive circuit 605. The fan 8 is connected to the fan control circuit 606. The power supply module 4 is connected to the input voltage protection circuit 607.

[0058] The chip control circuit 601 uses the main control chip 6011 with the model of STM32F103C8T6. The chip control circuit 601 controls each lower computer hardware through the main control chip 6011. The serial communication circuit 603 and the touch screen module 5 perform data interaction. The temperature acquisition circuit 604 controls the upper temperature sensor 213 and the lower temperature sensor 223. The heating drive circuit 605 controls the upper ceramic heating sheet 212 and the lower ceramic heating sheet 222. The fan control circuit 606 controls the fan 8.

[0059] The buck circuit 602 converts the DC 12V voltage input by the input voltage protection circuit 607 into the DC 3.3V voltage required for the operation of the main control chip 6011, the temperature acquisition circuit 604, and the program debugging circuit 609, and the DC 5V voltage required for the operation of the serial communication circuit 603.

[0060] The temperature acquisition circuit 604 is provided with a first input socket 6041 and a second input socket 6042. The lower temperature sensor 223 of the lower layer constant temperature heating module 22 is connected to the interface of the first input socket 6041 of the temperature acquisition circuit 604. The upper temperature sensor 213 of the upper layer constant temperature heating module 21 is connected to the interface of the second input socket 6042 of the temperature acquisition circuit 604.

[0061] The heating drive circuit 605 is provided with a first output terminal 6051 and a second output terminal 6052. The lower ceramic heating sheet 222 of the lower layer constant temperature heating module 22 is connected to the interface of the first output terminal 6051 of the heating drive circuit 605. The upper ceramic heating sheet 212 of the upper layer constant temperature heating module 21 is connected to the interface of the second output terminal 6052 of the heating drive circuit 605. The working voltage of the heating drive circuit 605 is DC 0V - 12V.

[0062] The fan control circuit 606 is provided with a fan output terminal 6061. The fan 8 is connected to the fan output terminal 6061. The operating voltage of the fan control circuit 606 is 12V DC. The input voltage protection circuit 607 is provided with a main board switch 6071 and an external input terminal 6072. The power supply module 4 is connected to the external input terminal 6072 of the input voltage protection circuit 607. The reset circuit 608 is provided with a reset switch 6081. The reset switch 6081 is used to reset the program when the program accidentally gets stuck during operation. The program debugging circuit 609 is an SWD program debugging circuit. The program debugging circuit 609 is used to download the control program of the debugging instrument.

[0063] As Figure 1 、 Figure 2 and Figure 12 shown, the air inlet 7 is of a blade structure, the fan 8 is a side-outlet turbo fan, the air outlet 9 is of a louver structure, and the air inlet 7 and the air outlet 9 are embedded in the housing 1. The air inlet 7 is arranged directly above the fan 8, and the air outlet 9 is arranged at an angle of 45 degrees directly in front of the fan 8. The fan 8 sucks air from the air inlet 7 to form a vortex and outputs wind through centrifugal force, discharging the excess heat of the upper-layer constant-temperature heating module 21 to the outside of the instrument through the air outlet 9.

[0064] As Figure 13 shown, the laminate 11 includes an aluminum plate 1103 and a tetrafluoro separator 1102. The aluminum plate 1103 is laid on the tetrafluoro separator 1102, and the aluminum plate 1103 and the tetrafluoro separator 1102 are arranged opposite to each other. The thickness of the aluminum plate 1103 is preferably 2mm, and the thickness of the tetrafluoro separator 1102 is preferably 2mm. The laminate 11 is fixed to the cushion block 103 in the housing 1 through the laminate positioning hole 1101, so as to isolate the constant-temperature interval from the outside when the lid 101 is opened, and ensure the stable temperatures of the upper-layer constant-temperature heating module 21 and the lower-layer constant-temperature heating module 22.

[0065] The main board module 6 is the control core. The external USB Type-C charger is connected to the charging module 3 and is connected to the lithium battery of the power supply module 4 through a wire to supply power to the lithium battery and the main board module 6. The upper-layer temperature sensor 213 and the lower-layer temperature sensor 223 of the instrument respectively detect the internal temperatures of the upper-layer constant-temperature heating module 21 and the lower-layer constant-temperature heating module 22, and transmit the temperature data to the main board module 6. The touch screen module 5 communicates with the main board module 6 bidirectionally through the USART protocol. The fan 8 operates through the 12V DC circuit on the main board module 6 to achieve the purpose of dissipating heat from the upper-layer constant-temperature heating module 21.

[0066] The touch screen module 5 presets the temperature and sends it to the main board module 6. The main board module 6 calculates the error e and the error change rate ec in real time. Using the error e and the error change rate ec as input quantities, and the proportional adjustment coefficient Kp, integral adjustment coefficient Ki, and differential adjustment coefficient Kd after dynamic programming according to the domain and fuzzy rules as output quantities, the duty cycle (PWM) of the heating sheet is finally adjusted in real time through the adaptive fuzzy PID algorithm for temperature control.

[0067] The handheld convection PCR instrument provided by the present utility model has a size of 135mm×60mm×50mm and an overall weight of 330g, meeting the handheld conditions. The overall structure of the instrument is simple, which is conducive to large-scale application. The instrument is built-in with a 3400mAh lithium battery and is equipped with a USB Type-C charging port to meet the outdoor use conditions. The operation interface of the instrument is simple and easy to operate. It only requires three simple steps of "turning on the machine - setting parameters - confirming parameters" to complete the control of each temperature region for realizing convection PCR. Both the heating part and the sensing part of the instrument adopt sheet heating elements and sheet thermistors. The temperature sensor is fully attached to the heating element, and the adaptive fuzzy PID control algorithm is used to eliminate the disturbance of the external environment to the heating module.

[0068] For a handheld convection PCR instrument of the present utility model, multiple amplification experiments were carried out using the same target DNA and reagents to prove the stability of the instrument.

[0069] First, extract the target DNA from Escherichia coli and prepare the convection PCR amplification system: The reaction is carried out in a 20μL system, and the system contains 2μL of 10-fold diluted PCR buffer (containing Mg 2+ )2μL, dNTP 0.8μL, target DNA (4ng / μL) 1.6μL, primers (2.5μM) 1.6μL each, Taq DNA polymerase 0.16μL, and distilled water 12.24μL. After centrifuging the reaction vessel, 3μL of silicone oil is added to avoid solution evaporation.

[0070] The primer sequences are: forward primer 5'-CAGTTTACCAACCGTCAT-3', reverse primer 5'-GAGCAACCGTTCCATTAC-3'.

[0071] Secondly, turn on the switch to start the handheld convection PCR instrument. Set the temperatures of the upper layer constant temperature heating module and the lower layer constant temperature heating module through the touch screen module to make it heat up and complete the preheating of the heating module. Then insert the reaction vessel into the reaction hole.

[0072] Then, set the amplification time to 30min and conduct 4 repeated experiments using the same target DNA and reagents.

[0073] Then, after 30 minutes, the reaction container was taken out and cooled to allow the convection PCR amplification reaction to complete. Finally, the amplified product was taken out for agarose gel (2%) electrophoresis analysis. The analysis results were as follows: Figure 15 shown.

[0074] Figure 15 The experimental conditions of lanes 1 to 4 are: target DNA fragment length is 168 bp; target DNA concentration is 4 ng / μL; the upper constant temperature heating module and the lower constant temperature heating module are set to 52°C and 91°C respectively; and the amplification reaction time is 30 min.

[0075] In summary, the utility model has the following advantages and beneficial effects:

[0076] 1. The utility model adopts a ceramic heating plate and a thermistor sensor, which has the advantages of small size, high heating efficiency, and good sensing accuracy, and effectively overcomes the defects of uneven heating and inaccurate temperature reading of the traditional PCR instrument heating rod.

[0077] 2. In a traditional convection PCR instrument, the lower constant temperature heating module and the upper constant temperature heating module are connected by screws with high thermal conductivity, and the temperature of the lower constant temperature heating module has a great influence on the temperature of the upper constant temperature heating module.

[0078] The utility model adopts a heat-insulating double-pass nylon stud connection between two constant temperature heating modules to separate the upper constant temperature heating module and the lower constant temperature heating module, thereby reducing the influence of the lower constant temperature heating module on the upper constant temperature heating module.

[0079] 3. The utility model is compact in size and has a built-in removable large-capacity lithium battery. It is charged using a USB Type-C charging head and can be used continuously for about 7 hours when fully charged. Compared with traditional PCR instruments, it has more application scenarios.

[0080] The utility model does not need to be connected to a computer, a mobile phone or other equipment, can be operated independently, does not require an expensive temperature-changing device, greatly reduces the instrument cost, has a simple instrument structure, and is easy to mass produce.

[0081] The above description is a detailed description of the preferred feasible embodiments of the utility model, but the embodiments are not intended to limit the scope of the patent application of the utility model. All equivalent changes or modified changes completed under the technical spirit disclosed by the utility model should fall within the patent scope covered by the utility model.

Claims

1. A handheld convection PCR instrument, characterized in that, It includes a housing, a constant-temperature heating module, a charging module, a power supply module, a touch screen module, a main board module, a fan, a cover body and a laminate. The charging module is connected to the power supply module, and the constant-temperature heating module, the power supply module and the touch screen module are respectively connected to the main board module; The power supply module is arranged at the bottom of the housing. The main board module is arranged above the power supply module and fixed inside the housing. The laminate is fixed inside the housing. The constant-temperature heating module is embedded in the laminate and fixed inside the housing. The convection tube is inserted into the constant-temperature heating module. The fan is installed on the laminate and located on one side of the constant-temperature heating module. The cover body is installed on the housing and located directly above the constant-temperature heating module; The constant-temperature heating module includes an upper-layer constant-temperature heating module and a lower-layer constant-temperature heating module. The upper-layer constant-temperature heating module is sequentially provided with a constant-temperature annealing aluminum block, an upper-layer ceramic heating sheet, an upper-layer temperature sensor and a constant-temperature extension aluminum block from top to bottom. The lower-layer constant-temperature heating module is sequentially provided with a constant-temperature denaturing aluminum block, a lower-layer ceramic heating sheet, a lower-layer temperature sensor and a PTFE backing plate from top to bottom.

2. The hand-held convection PCR instrument according to claim 1, wherein The upper-layer constant-temperature heating module and the lower-layer constant-temperature heating module are fixedly connected by a plurality of double-pass nylon studs. The height of the double-pass nylon studs is preferably 4 mm, and the shape of the double-pass nylon studs is preferably hexagonal.

3. The hand-held convection PCR instrument according to claim 1, characterized in that, The charging module is provided with a USB Type-C interface. The charging module is used to convert the DC 5V voltage input by an external USB Type-C charger into a DC 12V voltage and supply it to the power supply module.

4. A handheld convection PCR instrument according to claim 1, characterized in that, The power supply module includes a DC 12V lithium battery. The charging input voltage and the discharging output voltage of the power supply module are both DC 12V. The power supply module is charged through the charging module.

5. The hand-held convection PCR instrument according to claim 1, characterized in that, The touch screen module is a serial port screen. The touch screen module communicates with the main board module through the USART protocol.

6. The hand-held convection PCR instrument according to claim 1, characterized in that, The main board module is provided with a chip control circuit, a buck circuit, a serial communication circuit, a temperature acquisition circuit, a heating drive circuit, a fan control circuit, an input voltage protection circuit, a reset circuit and a program debugging circuit. The buck circuit, the serial communication circuit, the temperature acquisition circuit, the heating drive circuit, the fan control circuit, the input voltage protection circuit, the reset circuit and the program debugging circuit are respectively connected to the chip control circuit; The serial communication circuit, the temperature acquisition circuit, the input voltage protection circuit and the program debugging circuit are respectively connected to the buck circuit. The touch screen module is connected to the serial communication circuit. The upper-layer temperature sensor and the lower-layer temperature sensor are respectively connected to the temperature acquisition circuit. The upper-layer ceramic heating sheet and the lower-layer ceramic heating sheet are respectively connected to the heating drive circuit. The fan is connected to the fan control circuit. The power supply module is connected to the input voltage protection circuit.

7. A handheld convection PCR instrument according to claim 1, wherein, It also includes an air inlet and an air outlet. The air inlet is of a blade structure, and the air outlet is of a louver structure. The air inlet and the air outlet are embedded in the housing. The air inlet is arranged directly above the fan, and the air outlet is arranged at an angle of 45 degrees directly in front of the fan.

8. A hand-held convection PCR instrument according to claim 1, characterized in that, The cover body includes a lid and a guide rail. The lid reciprocates on the guide rail to open and close the lid.

9. A hand-held convection PCR instrument according to claim 1, wherein, The laminate includes a PTFE partition and an aluminum plate. The aluminum plate is covered on the PTFE partition and is arranged opposite to the PTFE partition.

10. The hand-held convection PCR instrument according to claim 9, characterized in that, The thickness of the aluminum plate is preferably 2 mm, and the thickness of the PTFE partition is preferably 2 mm.

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