Portable visual liquid droplet microreactor thermal stability experiment platform and application method thereof

Abstract

The application relates to a portable visual droplet microreactor thermal stability experiment platform and an application method thereof, and relates to the technical field of microfluidic instruments and equipment. Method: first, a heating module is started to preheat the equipment; after a temperature threshold is reached, a liquid droplet is sucked by using a liquid transfer gun, and the liquid droplet is diluted by using a 5% polyvinyl alcohol aqueous solution; then, the diluted liquid droplet is dropped into a channel of a PDMS chip; and finally, constant temperature thermal stability experiments of the diluted liquid droplet are carried out at three temperature thresholds of 55 DEG C, 75 DEG C and 95 DEG C, and the state of the liquid droplet in the PDMS chip is observed in real time. The application can obtain the portable visual droplet microreactor thermal stability experiment platform and the application method thereof.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microfluidic instrument equipment, and particularly relates to a portable visual liquid droplet microreactor thermal stability experiment platform and an application method thereof. BACKGROUND

[0002] A liquid droplet is a kind of multi-phase flow system formed by dispersing one or more small liquid in other incompatible (or immiscible) solutions, mainly including single emulsion droplets (such as oil-in-water or water-in-oil) and double emulsion droplets (such as water-in-oil-in-water forming a core-shell structure). With the development of liquid droplet microfluidic technology, the generated liquid droplets have the unique advantages of uniform size and isolation of internal and external environment. Therefore, the small liquid droplets become an excellent microreactor, which has important application prospects in the fields of chemical reactions, material synthesis and protein crystallization.

[0003] In these applications, the stability of the liquid droplet microreactor without fusion and rupture is a prerequisite to ensure the accuracy of analysis and detection results. Due to the action of surfactants, the single and double emulsion droplets prepared at present can maintain a stable state for a long time at room temperature, and researchers can use the liquid droplet microreactor to conveniently and efficiently carry out reactions and detection at room temperature. However, in addition to room temperature reactions, a large number of biochemical and material synthesis reactions need to be triggered under heating conditions, such as identification of reducing sugar and polymerase chain reaction. Moreover, the stability of the liquid droplet is related to the activity of the surfactant, the viscosity and density of the solution and other parameters, and the temperature will cause the activity of the surfactant, the density and viscosity of the solution to change, thereby affecting the stability of the liquid droplet. That is, the liquid droplet that can maintain stability at room temperature will often rupture or fuse at high temperature. In order to make the liquid droplet microreactor be used for the analysis of heat-triggered reactions, it is necessary to carry out liquid droplet thermal stability research to determine reasonable liquid droplet material parameters that can ensure the thermal stability of the liquid droplet. So far, there is still a lack of unified and referenceable rules for the thermal stability of the liquid droplet. The liquid droplet thermal stability experiment platform is designed for exploring the thermal stability of single or composite liquid droplets of various sizes and materials at different temperatures, which provides convenience for exploring the influence of different parameters on the thermal stability of the liquid droplet, thereby further promoting the application of the liquid droplet microreactor in the heating environment, such as PCR detection.

[0004] At present, researchers generally use water bath heating or direct heating to explore the stability of liquid droplets with micron-level diameter in a thermal field. Such methods need to use large equipment such as heating plates, microscopes and computers in the laboratory, and the overall energy utilization rate of the experiment is low and the flexibility is poor. The working conditions of different experiments cannot be accurately simulated, and the state change of the liquid droplets in the heating process cannot be observed in real time. In view of the above problems, it is necessary to provide a portable, integrated and low-cost visual liquid droplet thermal stability experiment platform to provide convenience for related thermal stability experiments and promote the early application of the technology in practice. SUMMARY

[0005] The purpose of the present application is to solve the above technical problems, and provide a portable visual liquid droplet microreactor thermal stability experiment platform and its application method.

[0006] A portable visual liquid droplet microreactor thermal stability experiment platform, comprising a shell 1, a heating module, a refrigeration module, an electronic micro-observation module, a PDMS chip 3, an auxiliary module and a control module.

[0007] The heating and heat dissipation module is composed of a heating area cover plate 2, a heating sheet 4, a red copper heat dissipation sheet 5 and a No. 1 fan 6.

[0008] The refrigeration module is composed of a No. 2 fan 15, a No. 3 fan 17, a No. 1 heat conducting block 18, a semiconductor refrigeration sheet 19, a No. 2 heat conducting block 20, a No. 4 fan 21 and a cold air flow channel 22.

[0009] The small electronic microscope 10 is composed of a CMOS camera 27, a conductive copper column 28, a lens 29 and an LED fill light 30.

[0010] The auxiliary module is composed of a sliding cover 7, a glass sheet 8, a button 12, a boat-shaped switch 13, an OLED display screen 16, a metal switch 31 and a power supply interface 32.

[0011] The inside of the shell 1 is provided with a recess, and the recess is sequentially provided with a red copper heat dissipation sheet 5, a heating sheet 4, a heating area cover plate 2 and a PDMS chip 3 from bottom to top, and the lower surface of the red copper heat dissipation sheet 5 is provided with a No. 1 fan 6.

[0012] The top of the recess of the shell 1 is provided with a sliding cover 7, and the shell 1 is provided with a sliding channel, and the sliding cover 7 is slidingly connected with the shell 1 through the sliding channel. The middle of the sliding cover 7 is provided with a glass sheet 8, and the glass sheet 8 is arranged directly above the PDMS chip 3.

[0013] The small electron microscope 10 is arranged above the glass sheet 8, and the small electron microscope 10 is connected with the side of the shell 1 through a transmission mechanism, the transmission mechanism controls the small electron microscope 10 to move in the horizontal or vertical direction of the glass sheet 8, and controls the small electron microscope 10 to be at an angle of 0-90° with the glass sheet 8; the top of the LED light supplement lamp 30 is provided with a lens 29, the top of the lens 29 is provided with a CMOS camera 27, and the CMOS camera 27 and the LED light supplement lamp 30 are electrically connected with the power supply through the conductive copper column 28;

[0014] The side of the shell 1 is provided with a semiconductor refrigerating sheet 19, the semiconductor refrigerating sheet 19 is divided into a heating surface and a refrigerating surface, the heating surface is connected with the No. 1 heat conduction block 18, and the side of the No. 1 heat conduction block 18 is provided with the No. 3 fan 17; the refrigerating surface is connected with the No. 2 heat conduction block 20, and the side of the No. 2 heat conduction block 20 is provided with the No. 4 fan 21, and the No. 4 fan 21 is arranged at the air inlet of the cold air flow channel 22, and the air outlet of the cold air flow channel 22 is arranged at the upper surface of the PDMS chip 3; and the No. 2 fan 15 is arranged at the side of the circuit board 33;

[0015] The upper surface of the shell 1 is respectively provided with an OLED display screen 16, a button 12 and a ship-shaped switch 13, and the side of the shell 1 is respectively provided with a metal switch 31 and a power supply interface 32;

[0016] The control module comprises an information processing module, a heating sheet driving circuit, a semiconductor refrigerating sheet driving circuit, a fan driving circuit 1, a fan driving circuit 2, a temperature data acquisition circuit, a CMOS driving circuit and an OLED display screen circuit, and the heating sheet driving circuit, the semiconductor refrigerating sheet driving circuit, the fan driving circuit 1, the fan driving circuit 2, the temperature data acquisition circuit, the CMOS driving circuit and the OLED display screen circuit are all arranged on the circuit board 33;

[0017] The heating control signal output end of the information processing module is connected with the heating control signal input end of the heating sheet driving circuit, and the heating control signal output end of the heating sheet driving circuit is connected with the heating control signal input end of the heating sheet 4;

[0018] The refrigerating control signal output end of the information processing module is connected with the refrigerating control signal input end of the semiconductor refrigerating sheet driving circuit, and the refrigerating control signal output end of the semiconductor refrigerating sheet driving circuit is connected with the refrigerating control signal input end of the semiconductor refrigerating sheet 19;

[0019] The control signal output end of the information processing module is connected with the control signal input end of the fan driving circuit 1 and the fan driving circuit 2 respectively, the control signal output end of the fan driving circuit 1 is connected with the control signal input end of the No.2 fan 15 and the No.3 fan 17 respectively, and the control signal output end of the fan driving circuit 2 is connected with the control signal input end of the No.1 fan 6 and the No.4 fan 21 respectively.

[0020] The temperature data output end of the temperature data acquisition circuit is connected with the temperature data input end of the information processing module, and the temperature data output end of the information processing module is connected with the temperature data input end of the heating sheet 4 and the semiconductor refrigeration sheet 19.

[0021] The control signal output end of the information processing module is connected with the control signal input end of the CMOS driving circuit, and the control signal output end of the CMOS driving circuit is connected with the control signal input end of the CMOS camera 27.

[0022] The display control signal output end of the information processing module is connected with the display control signal input end of the OLED display screen circuit, and the display control signal output end of the OLED display screen circuit is connected with the display control signal input end of the CMOS camera 27.

[0023] The application method of the portable visual liquid droplet micro-reactor thermal stability experiment platform is carried out according to the following steps:

[0024] First, the heating module is started to preheat the equipment, after reaching the temperature threshold, the liquid droplet is sucked by using a pipette, and then diluted by using a polyvinyl alcohol aqueous solution with a mass fraction of 5%, and then dropped into the channel of the PDMS chip 3, and then the diluted liquid droplet is subjected to constant temperature thermal stability experiment at three temperature thresholds of 55 DEG C, 75 DEG C and 95 DEG C, and the state of the liquid droplet in the PDMS chip 3 is observed in real time.

[0025] The beneficial effects of the present application are as follows:

[0026] The application firstly integrates the direct current driving circuit and the temperature data acquisition circuit to the control unit, to drive the heating sheet, the fan and the semiconductor refrigeration sheet to work, realize the temperature rising, falling and self-stabilizing functions; secondly, the small electronic microscope is integrated with the CMOS camera, the lens and the LED light supplement lamp as the core, has the functions of magnifying the image and transmitting to the upper computer for observation through WIFI, can clearly present the micron level droplets or silica particles, and can realize the telescopic mirror arm and the adjustable focal length by fixing the microscope with the mirror arm; thirdly, the WIFI communication function is integrated, the image can be transmitted in real time, the temperature sensor data can be read and sent to the upper computer to draw the temperature-time change curve; fourthly, the heating area is designed as the four-layer stacking structure of PDMS chip-heating sheet-heat dissipation red copper sheet-heat dissipation fan, which can ensure the efficiency of temperature transmission and the safety of heat dissipation; finally, in order to ensure the experimental efficiency and the accuracy of the results, such as the cooling rate of PCR temperature change, the semiconductor refrigeration sheet is specially installed on the side of the experimental platform, and when cooling is needed, the refrigeration surface fan starts to blow low-temperature gas into the reaction area.

[0027] The application can flexibly control the temperature, has the ability to carry out a series of micro thermal catalysis and thermal reactions taking droplets as the carrier, can also observe the process and effect of the micro thermal catalysis and thermal reactions in real time under the small electronic microscope, in addition, the thermal stability of single emulsion and double emulsion droplets generated by different materials, different sizes and different surfactants can be evaluated, and the transport taking droplets as the carrier and the PCR technology can be provided with parameter reference and technical support.

[0028] The application has important application prospects in the research of the thermal stability of single emulsion and double emulsion droplet microreactor and the thermal triggering reaction characteristics in the droplets (for example, the generation of nano cuprous oxide particle materials under the heating condition of Fehling reagent and reducing sugar in the droplets; the polymerase chain reaction in the droplets is used for the amplification detection of DNA).

[0029] The application can obtain a portable visual droplet microreactor thermal stability experimental platform and the application method thereof. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a three-dimensional side view of a portable visual droplet microreactor thermal stability experimental platform, 1 represents a shell, 2 represents a heating area cover plate, 3 represents a PDMS chip, 7 represents a sliding cover, 8 represents a glass sheet, 10 represents a small electronic microscope, 11 represents a mirror arm, 12 represents a button, 13 represents a boat-shaped switch, 14 represents an LED indicator light, 15 represents a No. 2 fan, 16 represents an OLED display screen;

[0031] Figure 2Figure 9 shows a three-dimensional side view of the portable visual liquid droplet microreactor thermal stability experiment platform of the present application, 9 represents a pressing sheet, 17 represents a No. 3 fan, 23 represents a knob, 24 represents a No. 1 set screw, 31 represents a metal switch, and 32 represents a power supply interface;

[0032] Figure 3 Figure 10 shows a three-dimensional cross-sectional view of the portable visual liquid droplet microreactor thermal stability experiment platform of the present application, 4 represents a heating sheet, 5 represents a red copper heat dissipation sheet, 6 represents a No. 1 fan, 17 represents a No. 3 fan, 18 represents a No. 1 heat conduction block, 19 represents a semiconductor refrigeration sheet, 20 represents a No. 2 heat conduction block, 21 represents a No. 4 fan, 22 represents a cold air flow channel, 25 represents a No. 2 set screw, 26 represents a gear, 27 represents a CMOS camera, 28 represents a conductive copper column, 29 represents a lens, 30 represents an LED fill light, 33 represents a circuit board, and 34 represents a single-chip microcomputer;

[0033] Figure 4 Figure 11 shows a diagram of the connection relationship between the various functional modules in the present application;

[0034] Figure 5 Figure 12 shows a schematic diagram of the preparation of a double-emulsion droplet microreactor in the present application;

[0035] Figure 6 Figure 13 shows a thermal stability experiment diagram of a double-emulsion droplet microreactor at 55°C in the present application;

[0036] Figure 7 Figure 14 shows a thermal stability experiment diagram of a double-emulsion droplet microreactor at 75°C in the present application;

[0037] Figure 8 Figure 15 shows a thermal stability experiment diagram of a double-emulsion droplet microreactor at 95°C in the present application;

[0038] Figure 9 Figure 16 shows a schematic diagram of the preparation of a single-emulsion droplet microreactor in the present application;

[0039] Figure 10 Figure 17 shows a thermal stability experiment diagram of a single-emulsion droplet microreactor at 55°C in the present application;

[0040] Figure 11 Figure 18 shows a thermal stability experiment diagram of a single-emulsion droplet microreactor at 75°C in the present application;

[0041] Figure 12 Figure 19 shows a thermal stability experiment diagram of a single-emulsion droplet microreactor at 95°C in the present application. DETAILED DESCRIPTION

[0042] Specific embodiment one: the portable visual liquid droplet microreactor thermal stability experiment platform of the present embodiment comprises a shell 1, a heating module, a refrigeration module, an electronic micro-display module, a PDMS chip 3, an auxiliary module, and a control module.

[0043] The heating and heat dissipation module is composed of a heating area cover plate 2, a heating sheet 4, a red copper heat dissipation sheet 5 and a No. 1 fan 6;

[0044] The refrigeration module is composed of a No. 2 fan 15, a No. 3 fan 17, a No. 1 heat conduction block 18, a semiconductor refrigeration sheet 19, a No. 2 heat conduction block 20, a No. 4 fan 21 and a cold air flow channel 22;

[0045] The small electronic microscope 10 is composed of a CMOS camera 27, a conductive copper column 28, a lens 29 and an LED light supplement lamp 30;

[0046] The auxiliary module is composed of a sliding cover 7, a glass sheet 8, a button 12, a boat-shaped switch 13, an OLED display screen 16, a metal switch 31 and a power supply interface 32;

[0047] The inside of the shell 1 is provided with a recess, and the recess is sequentially provided with the red copper heat dissipation sheet 5, the heating sheet 4, the heating area cover plate 2 and the PDMS chip 3 from bottom to top, and the lower surface of the red copper heat dissipation sheet 5 is provided with the No. 1 fan 6;

[0048] The upper part of the recess of the shell 1 is provided with the sliding cover 7, and the shell 1 is provided with a sliding channel, and the sliding cover 7 is slidingly connected with the shell 1 through the sliding channel; the middle of the sliding cover 7 is provided with the glass sheet 8, and the glass sheet 8 is arranged directly above the PDMS chip 3;

[0049] The small electronic microscope 10 is arranged above the glass sheet 8, and the small electronic microscope 10 is connected with the side surface of the shell 1 through a transmission mechanism, the transmission mechanism controls the small electronic microscope 10 to move in the horizontal or vertical direction of the glass sheet 8, and controls the small electronic microscope 10 to form an angle of 0-90° with the glass sheet 8; the upper part of the LED light supplement lamp 30 is provided with the lens 29, the upper part of the lens 29 is provided with the CMOS camera 27, and the CMOS camera 27 and the LED light supplement lamp 30 are electrically connected with the power supply through the conductive copper column 28;

[0050] The side surface of the shell 1 is provided with the semiconductor refrigeration sheet 19, the semiconductor refrigeration sheet 19 is divided into a heating surface and a refrigeration surface, the heating surface is connected with the No. 1 heat conduction block 18, and the side surface of the No. 1 heat conduction block 18 is provided with the No. 3 fan 17; the refrigeration surface is connected with the No. 2 heat conduction block 20, and the side surface of the No. 2 heat conduction block 20 is provided with the No. 4 fan 21, and the No. 4 fan 21 is arranged at the air inlet of the cold air flow channel 22, and the air outlet of the cold air flow channel 22 is arranged at the upper surface of the PDMS chip 3; the No. 2 fan 15 is arranged at the side surface of the circuit board 33;

[0051] The upper surface of the shell 1 is respectively provided with an OLED display screen 16, a button 12 and a ship-shaped switch 13, and the side surface of the shell 1 is respectively provided with a metal switch 31 and a power interface 32.

[0052] The control module comprises an information processing module, a heating sheet driving circuit, a semiconductor refrigeration sheet driving circuit, a fan driving circuit 1, a fan driving circuit 2, a temperature data acquisition circuit, a CMOS driving circuit and an OLED display screen circuit, and the heating sheet driving circuit, the semiconductor refrigeration sheet driving circuit, the fan driving circuit 1, the fan driving circuit 2, the temperature data acquisition circuit, the CMOS driving circuit and the OLED display screen circuit are all arranged on the circuit board 33.

[0053] The heating control signal output end of the information processing module is connected with the heating control signal input end of the heating sheet driving circuit, and the heating control signal output end of the heating sheet driving circuit is connected with the heating control signal input end of the heating sheet 4.

[0054] The refrigeration control signal output end of the information processing module is connected with the refrigeration control signal input end of the semiconductor refrigeration sheet driving circuit, and the refrigeration control signal output end of the semiconductor refrigeration sheet driving circuit is connected with the refrigeration control signal input end of the semiconductor refrigeration sheet 19.

[0055] The control signal output end of the information processing module is connected with the control signal input end of the fan driving circuit 1 and the fan driving circuit 2 respectively, the control signal output end of the fan driving circuit 1 is connected with the control signal input end of the No. 2 fan 15 and the No. 3 fan 17 respectively, and the control signal output end of the fan driving circuit 2 is connected with the control signal input end of the No. 1 fan 6 and the No. 4 fan 21 respectively.

[0056] The temperature data output end of the temperature data acquisition circuit is connected with the temperature data input end of the information processing module, and the temperature data output end of the information processing module is connected with the temperature data input end of the heating sheet 4 and the semiconductor refrigeration sheet 19.

[0057] The control signal output end of the information processing module is connected with the control signal input end of the CMOS driving circuit, and the control signal output end of the CMOS driving circuit is connected with the control signal input end of the CMOS camera 27.

[0058] The display control signal output end of the information processing module is connected with the display control signal input end of the OLED display screen circuit, and the display control signal output end of the OLED display screen circuit is connected with the display control signal input end of the CMOS camera 27.

[0059] The information processing module is a single-chip microcomputer. In this embodiment, the single-chip microcomputer is used as the core to control the heating sheet driving circuit, thereby controlling the temperature of the heating sheet 4. The semiconductor refrigeration sheet driving circuit and the fan driving circuit are only controlled by switching signals, that is, the single-chip microcomputer controls the start and stop of the semiconductor refrigeration sheet driving circuit and the fan driving circuit, and does not control the specific temperature and speed (the boat-shaped switch controls the power-on state of the corresponding element). The temperature data acquisition circuit is arranged together with other circuits, the temperature sensor contact head is in contact with the PDMS glass substrate, the CMOS driving circuit is used to drive the CMOS camera 27 to work, the OLED display screen 16 is connected with the single-chip microcomputer to display temperature information, and the CMOS camera 27 is connected with the WIFI module to transmit images in real time.

[0060] Specific embodiment two: the difference between this embodiment and specific embodiment one is that the transmission mechanism is composed of a mirror arm 11, a knob 23, a No. 1 set screw 24, a No. 2 set screw 25 and a gear 26, and the mirror arm 11 is composed of a horizontal arm and a vertical arm.

[0061] One end of the vertical arm is connected with the side surface of the shell 1, the other end of the vertical arm is connected with one end of the horizontal arm through the No. 2 set screw 25, and the other end of the horizontal arm is connected with the small electronic microscope 10.

[0062] The other steps are the same as those in specific embodiment one.

[0063] Specific embodiment three: the difference between this embodiment and specific embodiment one or two is that the vertical arm is provided with a tooth, the knob 23 is connected with the gear 26 through a connecting piece, the gear 26 is engaged with the tooth on the vertical arm, and the small electronic microscope 10 is controlled to move along the vertical direction of the glass sheet 8 by rotating the knob 23; a horizontal cavity is arranged in the horizontal arm, the No. 1 set screw 24 is arranged on the upper surface of the horizontal arm, one end of the connecting piece is arranged in the cavity of the horizontal arm and is fixed through the No. 1 set screw 24, and the other end of the connecting piece is connected with the small electronic microscope 10.

[0064] The other steps are the same as those in specific embodiment one or two.

[0065] Specific embodiment four: the difference between this embodiment and any one of specific embodiments one to three is that the PDMS chip 3 is fixed in the groove of the shell 1 through the pressing sheet 9.

[0066] The other steps are the same as those in specific embodiments one to three.

[0067] Specific embodiment five: the difference between this embodiment and any one of specific embodiments one to four is that a plurality of LED indicator lamps 14 are arranged on the upper surface of the shell 1.

[0068] The other steps are the same as those in specific embodiments one to four.

[0069] Sixth embodiment: The difference between this embodiment and one of the first to fifth embodiments is that the upper surface of the shell 1 is provided with four boat-shaped switches 13, respectively controlling the on-off of the heating sheet driving circuit, the semiconductor refrigeration sheet driving circuit, the fan driving circuit 1 and the fan driving circuit 2.

[0070] The other steps are the same as those in the first to fifth embodiments.

[0071] Seventh embodiment: The difference between this embodiment and one of the first to sixth embodiments is that the upper surface of the shell 1 is provided with three keys 12, respectively controlling the start, pause and reset of the program.

[0072] The other steps are the same as those in the first to sixth embodiments.

[0073] Eighth embodiment: The difference between this embodiment and one of the first to seventh embodiments is that the control module further includes a WIFI module, the WIFI module is arranged on the circuit board 33, and the control signal output end of the information processing module is connected with the control signal input end of the upper computer through the WIFI module.

[0074] The other steps are the same as those in the first to seventh embodiments.

[0075] Ninth embodiment: The application method of the portable visual liquid droplet microreactor thermal stability experiment platform according to the ninth embodiment is as follows:

[0076] First, start the information processing module to control the heating sheet 4 to preheat the PDMS chip 3 through the heating sheet driving circuit, and turn on the No. 2 fan 15 and the No. 3 fan 17 at the same time; after reaching the temperature threshold, use a liquid droplet gun to suck the liquid droplet, and use a 5% polyvinyl alcohol aqueous solution to dilute it, then drop it into the channel of the PDMS chip 3, and then start the information processing module to control the heating sheet 4 to heat the PDMS chip 3 through the heating sheet driving circuit, and control the semiconductor refrigeration sheet 19 to cool the PDMS chip 3 through the semiconductor refrigeration sheet driving circuit, then respectively carry out constant temperature thermal stability experiment on the diluted liquid droplet at three temperature thresholds of 55℃, 75℃ and 95℃, and observe the state of the liquid droplet in the PDMS chip 3 in real time.

[0077] Specific implementation ten: the difference between this embodiment and specific implementation nine is that when the diluted droplets complete the constant temperature thermal stability experiment at 55℃, turn on No. 1 fan 6 and No. 4 fan 21 to cool the experimental area, and after cooling to room temperature, the constant temperature thermal stability experiment of the diluted droplets at 75℃ is carried out again; after the constant temperature thermal stability experiment of the diluted droplets at 75℃ is completed, repeat the above operation, and then carry out the constant temperature thermal stability experiment of the diluted droplets at 95℃.

[0078] The droplets are water-in-oil-in-water double emulsion droplets or water-in-oil single emulsion droplets.

[0079] The water-in-oil-in-water double emulsion droplets are prepared by the following steps:

[0080] First, the inner phase solution is injected through the inlet of the injection tube, the middle phase solution is injected through the annular inlet formed between the outer wall of the injection tube and the inner wall of the square tube, and the outer phase solution is injected through the annular inlet formed between the outer wall of the collection tube and the inner wall of the square tube; then the flow rate of the outer phase solution is controlled to be 7150-7280 μL / h, the flow rate of the middle phase solution is controlled to be 700-850 μL / h, and the flow rate of the inner phase solution is controlled to be 800-1000 μL / h, the prepared water-in-oil-in-water double emulsion droplets with an outer diameter of 250-320 μm and a shell thickness of 30-38 μm flow into the tapered structure port of the collection tube, and flow out from the outlet at the right end of the collection tube;

[0081] The inner phase solution is a methylene blue dyed polyvinyl alcohol aqueous solution with a mass fraction of 5%; the middle phase solution is a mixed solution of PDMS and dimethyl silicone oil with a viscosity of 50, in a volume ratio of 3:7; and the outer phase solution is a polyvinyl alcohol aqueous solution with a mass fraction of 5%;

[0082] The water-in-oil single emulsion droplets are prepared by the following steps:

[0083] First, the inner phase solution is injected through the inlet of the injection tube, and the outer phase solution is injected through the annular inlet formed between the outer wall of the collection tube and the inner wall of the square tube; then the flow rate of the outer phase solution is controlled to be 4320-4400 μL / h and the flow rate of the inner phase solution is controlled to be 200-250 μL / h, the prepared water-in-oil single emulsion droplets with a diameter of 55-65 μm flow into the tapered structure port of the collection tube, and flow out from the outlet at the right end of the collection tube;

[0084] The inner phase solution is a methylene blue dyed polyvinyl alcohol aqueous solution with a mass fraction of 3%; the outer phase solution is composed of fluorinated oil and perfluoropolyoxypropylene-polyethylene-perfluoropolyoxypropylene, and the mass fraction of perfluoropolyoxypropylene-polyethylene-perfluoropolyoxypropylene is 3%.

[0085] The other steps are the same as those in specific implementation nine.

[0086] The beneficial effects of the present application are verified by the following examples:

[0087] Example 1:

[0088] (1) Installation and operation logic of the device;

[0089] In this embodiment, the heating area is stacked by the heating area cover plate 2, the PDMS chip 3, the heating sheet 4, the red copper heat sink 5 and the No. 1 fan 6. The upper surface of the heating sheet 4 is in direct contact with the PDMS chip 3. The glass bottom sheet of the PDMS chip 3 is only 0.15 mm thick, which maximizes the heat transfer efficiency. At the same time, the lower surface of the heating sheet 4 is in contact with the red copper heat sink 5, so that the heat of the lower surface is freely diffused into the heat sink, and is blown out by the No. 1 fan 6, ensuring safety during use.

[0090] In this embodiment, a small electron microscope 10 is added to monitor the test area in real time. The small electron microscope 10 is internally composed of a CMOS camera 27, a conductive copper column 28, a lens 29 and an LED fill light 30. The image is imaged on the CMOS camera 27 under the magnification of the lens 29, and the LED fill light 30 ensures that the imaging area is bright enough. The two conductive copper columns 28 can not only power the LED fill light 30 board, but also serve as a slide rail to correct the position of the lens 29.

[0091] In this embodiment, the small electron microscope 10 is perpendicular to the imaging surface to realize real-time monitoring, mainly relying on the support of the mirror arm 11. The mirror arm 11 is connected with the shell 1 to realize a rotating motion within a range of 90°, so that the mirror arm 11 can be laid down or stood up. In the axial position, the gear 26 is engaged with the teeth on the arm, and the focus can be adjusted by controlling the up and down movement of the microscope through the adjusting knob 23. In the radial position, the mirror arm 11 can be stretched or contracted by loosening the No. 1 tight bolt 24 and manually adjusting the arm length. After fixing the imaging position, the position of the PDMS chip 3 can also be adjusted to change the imaging position.

[0092] This embodiment is designed for detecting the thermal stability of droplets, and the temperature change rule can be flexibly adjusted. In order to accelerate the cooling speed, a refrigeration device is additionally installed on the side in addition to the No. 1 fan 6. The refrigeration device is composed of a No. 3 fan 17, a No. 1 heat conduction block 18, a semiconductor refrigeration sheet 19, a No. 2 heat conduction block 20, a No. 4 fan 21 and a cold air flow channel 22. The No. 1 heat conduction block 18 is attached to the hot surface of the semiconductor refrigeration sheet to diffuse the heat and blow it out through the No. 3 fan 17. The No. 2 heat conduction block 20 is attached to the cold surface of the semiconductor refrigeration sheet, and the low-temperature air is blown into the test area along the cold air flow channel 22 through the No. 4 fan 21 to help reduce the temperature.

[0093] In this embodiment, the information processing module is based on an STM32F103C8T6 microcontroller and externally integrates a heating element driver circuit, a semiconductor cooling element driver circuit, fan driver circuit 1, fan driver circuit 2, a temperature data acquisition circuit, a CMOS driver circuit, a WIFI module, and an OLED display circuit. The information processing module internally executes a positional PID algorithm, which can achieve temperature self-stabilization by adjusting the PWM output model. The heating element driver circuit uses a BTN7971 driver chip as its core, driving the high-temperature alumina ceramic heating element to operate at a maximum power of DC-36V and 250W. The semiconductor cooling element driver circuit uses an L298N chip as its core, driving it to operate at DC-12V and 24W, with a maximum temperature difference of 60℃ between the hot and cold surfaces. Both fan driver circuits 1 and 2 use an L9110S chip as their core; fan driver circuit 1 is normally open, driving fans 15 (number 2) and 17 (number 3) to maintain operation. For daily heat dissipation, fan drive circuit 2 is activated during the cooling process, driving fan 6 (number 1) to dissipate heat from the lower surface of the heating element and fan 21 (number 4) to blow low-temperature air to the heating area. Temperature sensors detect the temperature data of the semiconductor cooling chip and the heating element, respectively, and feed it back to the information processing module. The WIFI module is responsible for communicating with the host computer, uploading images and temperature data of the experimental platform to the host computer, and receiving temperature control strategies from the host computer. The OLED display circuit drives a 0.96-inch OLED display 16 to display the current temperature, desired temperature, PID parameters, and WIFI communication status.

[0094] In this embodiment, one metal switch 31, four rocker switches 13, and three buttons 12 are provided. The metal switch 31 has a diameter of 16mm and can handle a maximum DC current of 10A, serving as the main power switch for the experimental platform. The four rocker switches 13 control the on / off states of the heating element drive circuit, the semiconductor cooling element drive circuit, fan drive circuit 1, and fan drive circuit 2, respectively. The three buttons 12 control the program's start, pause, and reset functions.

[0095] The droplets in this embodiment are water-in-oil-in-water double emulsion droplets or oil-in-water single emulsion droplets;

[0096] (2) Preparation of dual emulsion droplet microreactors;

[0097] Using glass capillary chips (such as Figure 5A water-in-oil-in-water double emulsion droplet was generated. The inner diameter of the inlet tube of the chip was 50 μm, the inner diameter of the receiving tube was 250 μm, and the distance between the inlet tube and the receiving tube was 150 μm. The inner phase solution was a 5% (by mass) polyvinyl alcohol aqueous solution dyed with methylene blue, the middle phase was a mixed solution of PDMS (A glue) and 50 viscosity dimethyl silicone oil at a ratio of 3:7, and the outer phase was a 5% (by mass) polyvinyl alcohol aqueous solution. By controlling the fluid flow rate of the outer phase Q1 = 7210 μL / h, the fluid flow rate of the middle phase Q2 = 780 μL / h, and the fluid flow rate of the inner phase Q3 = 920 μL / h, a water-in-oil-in-water double emulsion droplet with an outer diameter of 290 μm and a shell thickness of 32 μm was successfully prepared and collected.

[0098] Thermal stability experiment of double emulsion droplet;

[0099] The collected double emulsion droplet was left to stand for 2 hours to wait for its state to stabilize. The heating module and the top electron microscope were turned on to preheat the device, and after reaching the temperature threshold, a portion of the droplet was sucked out using a pipette and diluted with a 5% (by mass) polyvinyl alcohol aqueous solution and dropped into the microchannel of the PDMS chip. The droplet was subjected to constant temperature thermal stability experiments at three temperature thresholds of 55°C, 75°C, and 95°C, and the state of the double emulsion droplet in the chip was observed in real time.

[0100] Figure 6 Fig. 4 shows the thermal stability experiment of the double emulsion droplet microreactor at 55°C in the present application, Figure 7 Fig. 5 shows the thermal stability experiment of the double emulsion droplet microreactor at 75°C in the present application; Figures 6-7 Figs. 4 and 5 respectively show the thermal stability performance of the double emulsion droplet in a constant temperature environment of 55°C and 75°C. In a test time of 150 s, a small amount of droplets had core rupture, which may be caused by slight vibration or uneven droplet shell thickness. This is sufficient to show that the droplet can better maintain its shape at 75°C.

[0101] Figure 8 Fig. 6 shows the thermal stability experiment of the double emulsion droplet microreactor at 95°C in the present application; Figure 7 Fig. 6 shows the thermal stability performance of the double emulsion droplet in a constant temperature environment of 95°C. In a test time of 150 s, a large number of droplets had rupture, and oil shells were aggregated to form oil droplets floating on the surface of the outer phase aqueous solution. This shows that the droplet cannot maintain its original shape in a 95°C environment. Therefore, it also indirectly proves that the double emulsion droplet of this size generated using this type of material cannot be applied to a polymerase chain reaction with a maximum reaction temperature of 95°C.

[0102] (3) Preparation of single emulsion droplet microreactor;

[0103] A glass capillary chip (such as Figure 9The water-in-oil single emulsion droplets are generated; the diameter of the left side inlet tube of the microfluidic chip is 40 μm, the diameter of the right side collection tube is about 120 μm, and the distance between the two tubes is 60 μm;

[0104] The inner phase solution is injected through the inlet of the inlet tube, and the outer phase solution is injected through the annular inlet formed between the outer wall of the collection tube and the inner wall of the square tube; then the flow rate of the outer phase solution is controlled to be 4320-4400 μL / h, and the flow rate of the inner phase solution is controlled to be 200-250 μL / h; the water-in-oil single emulsion droplets with a diameter of 60 μm generated are flowed into the tapered structure port of the collection tube, and then flowed out from the outlet at the right end of the collection tube; the single emulsion droplet microreactor generated is subjected to a certain degree of thermal buoyancy convection at temperatures of 55 ℃, 75 ℃ and 95 ℃ (as shown in Figures 10-12 The single emulsion droplet microreactor generated is subjected to a certain degree of thermal buoyancy convection at temperatures of 55 ℃, 75 ℃ and 95 ℃ (as shown in

[0105] The inner phase solution is a methylene blue dyed polyvinyl alcohol aqueous solution with a mass fraction of 3%; the outer phase solution is composed of fluorinated oil and perfluoropolyoxypropylene-polyethylene-perfluoropolyoxypropylene, the fluorinated oil (HFE7500) is the basic oil phase, and perfluoropolyoxypropylene-polyethylene-perfluoropolyoxypropylene (PFPE-PEG-PFPE) with a mass fraction of 3% is added as a surfactant.

Claims

1. A portable, visualized experimental platform for the thermal stability of droplet microreactors, characterized in that... The droplet microreactor thermal stability experimental platform includes a shell (1), a heating module, a cooling module, a small electron microscope (10), a PDMS chip (3), an auxiliary module, and a control module; The heating module consists of a heating zone cover plate (2), a heating element (4), a copper heat sink (5), and a No. 1 fan (6); The cooling module consists of fan No. 2 (15), fan No. 3 (17), heat conduction block No. 1 (18), semiconductor cooling chip (19), heat conduction block No. 2 (20), fan No. 4 (21) and cold air flow channel (22); The miniature electron microscope (10) consists of a CMOS camera (27), a conductive copper column (28), a lens (29), and an LED fill light (30); The auxiliary module consists of a sliding cover (7), a glass plate (8), a button (12), a rocker switch (13), an OLED display (16), a metal switch (31), and a power interface (32); The interior of the housing (1) is provided with a groove, and a copper heat sink (5), a heating element (4), a heating zone cover plate (2) and a PDMS chip (3) are arranged in the groove from bottom to top. A No. 1 fan (6) is provided on the lower surface of the copper heat sink (5). A sliding cover (7) is provided above the groove of the housing (1), and a slide is provided on the housing (1). The sliding cover (7) is slidably connected to the housing (1) through the slide. A glass plate (8) is provided in the middle of the sliding cover (7), and the glass plate (8) is located directly above the PDMS chip (3). The small electron microscope (10) is positioned above the glass slide (8). The small electron microscope (10) is connected to the side of the housing (1) through a transmission mechanism. The transmission mechanism controls the small electron microscope (10) to move horizontally or vertically along the glass slide (8) and controls the small electron microscope (10) to be at an angle of 0~90° with the glass slide (8). A lens (29) is positioned above the LED fill light (30). A CMOS camera (27) is positioned above the lens (29). Both the CMOS camera (27) and the LED fill light (30) are electrically connected to the power supply through conductive copper pillars (28). The housing (1) is provided with a semiconductor cooling chip (19) on its side. The semiconductor cooling chip (19) is divided into a heating surface and a cooling surface. The heating surface is connected to the No. 1 heat conduction block (18), and the No. 3 fan (17) is provided on the side of the No. 1 heat conduction block (18). The cooling surface is connected to the No. 2 heat conduction block (20), and the No. 4 fan (21) is provided on the side of the No. 2 heat conduction block (20). The No. 4 fan (21) is located at the air inlet of the cold air flow channel (22), and the air outlet of the cold air flow channel (22) is located on the upper surface of the PDMS chip (3). The No. 2 fan (15) is located on the side of the circuit board (33). The upper surface of the housing (1) is provided with an OLED display screen (16), a button (12) and a rocker switch (13), and the side of the housing (1) is provided with a metal switch (31) and a power interface (32). The control module includes an information processing module, a heating element driving circuit, a semiconductor cooling element driving circuit, a fan driving circuit 1, a fan driving circuit 2, a temperature data acquisition circuit, a CMOS driving circuit, and an OLED display circuit. The heating element driving circuit, the semiconductor cooling element driving circuit, the fan driving circuit 1, the fan driving circuit 2, the temperature data acquisition circuit, the CMOS driving circuit, and the OLED display circuit are all mounted on a circuit board (33). The heating control signal output terminal of the information processing module is connected to the heating control signal input terminal of the heating element driving circuit, and the heating control signal output terminal of the heating element driving circuit is connected to the heating control signal input terminal of the heating element (4). The cooling control signal output terminal of the information processing module is connected to the cooling control signal input terminal of the semiconductor cooling chip driving circuit, and the cooling control signal output terminal of the semiconductor cooling chip driving circuit is connected to the cooling control signal input terminal of the semiconductor cooling chip (19). The control signal output terminal of the information processing module is connected to the control signal input terminal of the fan drive circuit 1 and the fan drive circuit 2 respectively. The control signal output terminal of the fan drive circuit 1 is connected to the control signal input terminal of the No. 2 fan (15) and the No. 3 fan (17) respectively. The control signal output terminal of the fan drive circuit 2 is connected to the control signal input terminal of the No. 1 fan (6) and the No. 4 fan (21) respectively. The temperature data output terminal of the temperature data acquisition circuit is connected to the temperature data input terminal of the information processing module, and the temperature data output terminal of the information processing module is connected to the temperature data input terminals of the heating element (4) and the semiconductor cooling element (19). The control signal output terminal of the information processing module is connected to the control signal input terminal of the CMOS driving circuit, and the control signal output terminal of the CMOS driving circuit is connected to the control signal input terminal of the CMOS camera (27). The display control signal output terminal of the information processing module is connected to the display control signal input terminal of the OLED display circuit, and the display control signal output terminal of the OLED display circuit is connected to the display control signal input terminal of the CMOS camera (27).

2. The portable, visualized droplet microreactor thermal stability experimental platform according to claim 1, characterized in that... The transmission mechanism consists of a mirror arm (11), a knob (23), a No. 1 set screw (24), a No. 2 set screw (25), and a gear (26). The mirror arm (11) consists of a horizontal arm and a vertical arm. One end of the vertical arm is connected to the side of the housing (1), and the other end of the vertical arm is connected to one end of the horizontal arm by a No. 2 set bolt (25). The other end of the horizontal arm is connected to the small electron microscope (10).

3. The portable, visualized droplet microreactor thermal stability experimental platform according to claim 2, characterized in that... The vertical arm is provided with teeth, and the knob (23) is connected to the gear (26) through the connector. The gear (26) meshes with the teeth on the vertical arm. By turning the knob (23), the small electron microscope (10) is controlled to move in the vertical direction of the glass slide (8). The horizontal arm is provided with a horizontal cavity. The upper surface of the horizontal arm is provided with a No. 1 set bolt (24). One end of the connector is set in the cavity of the horizontal arm and is fixed by the No. 1 set bolt (24). The other end of the connector is connected to the small electron microscope (10).

4. The portable, visualized droplet microreactor thermal stability experimental platform according to claim 1, characterized in that... The PDMS chip (3) is fixed in the groove of the housing (1) by a pressure plate (9).

5. The portable, visualized droplet microreactor thermal stability experimental platform according to claim 1, characterized in that... The upper surface of the housing (1) is provided with several LED indicator lights (14).

6. The portable, visualized droplet microreactor thermal stability experimental platform according to claim 1, characterized in that... The upper surface of the housing (1) is provided with four boat-shaped switches (13) to control the on / off state of the heating element drive circuit, the semiconductor cooling element drive circuit, the fan drive circuit 1 and the fan drive circuit 2 respectively.

7. The portable, visualized droplet microreactor thermal stability experimental platform according to claim 1, characterized in that... The upper surface of the housing (1) is provided with three buttons (12) to control the start, pause and reset of the program respectively.

8. The portable, visualized droplet microreactor thermal stability experimental platform according to claim 1, characterized in that... The control module also includes a WIFI module, which is mounted on the circuit board (33). The control signal output terminal of the information processing module is connected to the control signal input terminal of the host computer through the WIFI module.

9. The application method of the portable visual droplet microreactor thermal stability experimental platform as described in any one of claims 1-8, characterized in that... This application method is performed according to the following steps: First, the information processing module is started to control the heating element (4) to preheat the PDMS chip (3) through the heating element drive circuit, and at the same time, the No. 2 fan (15) and the No. 3 fan (17) are turned on. After the temperature threshold is reached, the droplet is taken with a pipette and diluted with a 5% polyvinyl alcohol aqueous solution. Then, it is dropped into the channel of the PDMS chip (3). The information processing module is started again to control the heating element (4) to heat the PDMS chip (3) through the heating element drive circuit. At the same time, the semiconductor cooling chip (19) is controlled to cool the PDMS chip (3) through the semiconductor cooling chip drive circuit. Then, the constant temperature thermal stability test is carried out on the diluted droplet at three temperature thresholds of 55℃, 75℃ and 95℃ respectively, and the state of the droplet in the PDMS chip (3) is observed in real time.

10. The application method of the portable visual droplet microreactor thermal stability experimental platform according to claim 9, characterized in that... After the diluted droplets completed the isothermal thermal stability test at 55°C, fan No. 1 (6) and fan No. 4 (21) were turned on to cool the experimental area. After the temperature dropped to room temperature, the isothermal thermal stability test of the diluted droplets at 75°C was carried out. After completing the isothermal thermal stability test of the diluted droplets at 75℃, repeat the above operation and then conduct the isothermal thermal stability test of the diluted droplets at 95℃. The droplets are either water-in-oil-in-water double emulsion droplets or oil-in-water single emulsion droplets; The water-in-oil-in-water double emulsion droplets are prepared according to the following steps: First, the inner phase solution is injected through the inlet of the injection tube, and the intermediate phase solution is injected through the annular inlet formed between the outer wall of the injection tube and the inner wall of the square tube. At the same time, the outer phase solution is injected through the annular inlet formed between the outer wall of the collection tube and the inner wall of the square tube. Then, the flow rates of the outer phase solution, the intermediate phase solution, and the inner phase solution are controlled at 7150~7280 μL / h, 700~850 μL / h, and 800~1000 μL / h, respectively. The resulting water-in-oil-in-water double emulsion droplets with an outer diameter of 250~320 μm and a shell thickness of 30~38 μm flow into the conical structure port of the collection tube and flow out from the outlet at the right end of the collection tube. The inner phase solution is a 5% (w / w) polyvinyl alcohol aqueous solution stained with methylene blue; the intermediate phase solution is a mixture of PDMS and dimethyl silicone oil with a viscosity of 50 at a volume ratio of 3:7; the outer phase solution is a 5% (w / w) polyvinyl alcohol aqueous solution. The water-in-oil monoemulsion droplets are prepared according to the following steps: First, the inner phase solution is injected through the inlet of the injection tube, while the outer phase solution is injected through the annular inlet formed between the outer wall of the collection tube and the inner wall of the square tube. Then, the flow rate of the outer phase solution is controlled at 4320~4400 μL / h and the flow rate of the inner phase solution is controlled at 200~250 μL / h. The resulting water-in-oil monoemulsion droplets with a diameter of 55~65 μm flow into the conical structure port of the collection tube and flow out from the outlet at the right end of the collection tube. The inner phase solution is a 3% (w / w) polyvinyl alcohol aqueous solution stained with methylene blue; the outer phase solution is composed of fluorinated oil and perfluoropolyoxypropylene-polyethylene-perfluoropolyoxypropylene, wherein the mass fraction of perfluoropolyoxypropylene-polyethylene-perfluoropolyoxypropylene is 3%.

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