Plasmid DNA filter paper elution component, automatic microfluidic system and elution method

Abstract

This application relates to the field of plasmid DNA elution on filter paper, and particularly to a plasmid DNA filter paper elution component, an automatic microfluidic system and an elution method. By setting the flow direction, flow rate and flow volume of the eluent for the chip removal, the plasmid DNA filter paper placed in the elution chamber is eluted according to the set step program. The dissolution and diffusion of plasmid DNA are accelerated by step-by-step ultrasonic treatment, and a quantitative new eluent is pumped into the elution chamber by an injection pump to replace the eluent in the elution chamber, so as to combine the plasmid DNA filter paper drying, transportation and storage technology with the microfluidic technology. There is no cumbersome centrifugation step, the structure is simple, the operation is convenient, the labor is saved, the plasmid DNA filter paper elution process is standardized, the rapid experimental requirements of the laboratory are met, and high-efficiency and high-quality plasmid DNA filter paper elution is truly realized.

Description

Technical Field

[0001] This application relates to the technical field of plasmid DNA elution on filter paper, and particularly to a plasmid DNA filter paper elution component, an automatic microfluidic system, and an elution method. Background Art

[0002] For the safe transportation and stable preservation of plasmid DNA, in the international transportation of plasmid DNA, the scientific community widely uses dot-blot mailing, that is, using a pencil to draw a circle with a diameter of 0.2 cm - 0.4 cm on a sterilized filter paper, spotting a certain volume of plasmid DNA within the circle, allowing it to air-dry naturally, and then placing it in a self-sealing bag for sample mailing. After receiving the sample, the researcher cuts out the filter paper with the drawn circle, places it in a sample tube, adds a certain amount of TE solution or double-distilled water to dissolve it, allows it to stand at room temperature for 30 minutes to dissolve, and then centrifuges and aspirates the supernatant for subsequent experiments.

[0003] Since plasmid DNA is carried by the filter paper, there are variables in environmental temperature and time during the mailing process, and plasmid DNA is somewhat degraded, resulting in incomplete elution. After receiving the filter paper, researchers generally soak the filter paper in an eluent in a sample tube, let it stand at room temperature for 30 minutes, then centrifuge and aspirate the supernatant plasmid DNA solution. Since plasmid DNA moves from the micropores of the filter paper from a high-concentration area to a low-concentration area by natural dissolution and diffusion methods such as van der Waals forces under static conditions, and aspirating the upper liquid causes plasmid DNA to not be completely eluted from the filter paper, resulting in low recovery efficiency. Especially for plasmid DNA samples that are originally trace amounts, it is very likely to affect the progress of subsequent experiments. At the same time, manual sample addition and static elution take too long, and the experimental operation cannot be standardized. Moreover, the state of the filter paper placed in the sample tube is different. In order to be completely immersed in the eluent, the filter paper needs to be folded and squeezed, which causes physical and mechanical damage to plasmid DNA and results in the breakage of the DNA ring of plasmid DNA.

[0004] In summary, there are disadvantages of low plasmid DNA recovery rate, long elution time, non-standardized operation, and mechanical damage in the current plasmid DNA filter paper static soaking elution method. Summary of the Invention

[0005] Embodiments of this application provide a plasmid DNA filter paper elution component, an automatic microfluidic system, and an elution method to solve the technical problems of low plasmid DNA recovery rate, long elution time, non-standardized operation, and mechanical damage in the current plasmid DNA filter paper static soaking elution method.

[0006] To this end, according to one aspect of this application, a plasmid DNA filter paper elution component is provided, including:

[0007] The elution chip includes a chip body and a sealing cover. An elution chamber, three liquid inlet channels and three liquid outlet channels communicating with the elution chamber are provided in the chip body. An opening, three liquid inlets and one liquid outlet are provided on the upper surface of the chip body. The opening is correspondingly communicated with the elution chamber for placing a filter paper containing plasmid DNA. The sealing cover is used to seal the opening. The three liquid inlets are respectively and correspondingly communicated with one end of the three liquid inlet channels far away from the elution chamber. The liquid outlet is communicated with one end of the three liquid outlet channels far away from the elution chamber;

[0008] The chip carrier has a positioning groove at the top for placing the elution chip. A through hole penetrating the chip carrier up and down is provided at the bottom of the positioning groove. After the elution chip is placed in the positioning groove, the elution chamber is located above the through hole; and

[0009] The ultrasonic vibration mechanism includes a water bag and an ultrasonic probe arranged in the water bag. The water bag extends into the positioning groove through the through hole. The water bag is used to fit the position of the chip body corresponding to the elution chamber.

[0010] Optionally, the chip body includes a bottom sealing plate and a substrate that are mutually attached. The elution chamber, the three liquid inlet channels and the three liquid outlet channels are all arranged between the bottom sealing plate and the substrate. The opening, the three liquid inlets and the one liquid outlet are all arranged on the side of the substrate facing away from the bottom sealing plate.

[0011] Optionally, the aperture of the through hole gradually decreases from the end far away from the positioning groove to the end close to the positioning groove. The water bag is in a frustum shape adapted to the shape of the through hole.

[0012] Optionally, the ultrasonic vibration mechanism further includes a water cooling unit. The inside of the water bag is filled with water. An inlet joint and an outlet joint are provided on the water bag. The inlet joint and the outlet joint are respectively connected to the outlet and inlet of the water cooling unit through water pipes. The water cooling unit cools the water in the water bag by means of water circulation.

[0013] Optionally, the elution chamber has a planar chamber wall arranged oppositely and an arc-shaped chamber wall protruding away from the planar chamber wall. The three liquid inlet channels are communicated with the planar chamber wall. The three liquid outlet channels are communicated with the arc-shaped chamber wall. The direction of one of the liquid inlet channels accessing the elution chamber is perpendicular to the planar chamber wall. The directions of the other two liquid inlet channels accessing the elution chamber are perpendicular to each other. The directions of the three liquid inlet channels accessing the elution chamber intersect at the center of the elution chamber.

[0014] Optionally, the closed cover includes a cover body, a plunger, and a silicone coating. The plunger is disposed on one side of the cover body, and the diameter of the plunger is smaller than that of the cover body. The silicone coating is disposed on the side of the cover body facing the plunger and surrounds the plunger. The plunger is used to block the opening, and the silicone coating is used to contact the periphery of the opening to play a sealing role.

[0015] According to another aspect of the present application, an automatic microfluidic system is provided, which includes three eluent sample tubes, one eluent collection tube, an injection pump, a touch industrial computer, and the plasmid DNA filter paper elution assembly as described above;

[0016] The three liquid inlets correspond to the three eluent sample tubes one by one and are connected through inlet capillary tubes. The liquid outlet is connected to the eluent collection tube through an outlet capillary tube. The injection pump is used to pump sterile filtered air into the three eluent sample tubes to increase the air pressure in the eluent sample tubes, so as to pump the eluent in the eluent sample tubes into the elution chamber and then flow into the eluent collection tube. The touch industrial computer is electrically connected to the injection pump and the ultrasonic probe.

[0017] Optionally, the eluent sample tube includes a tube body and a tube cap detachably disposed on the tube body. The end of the inlet capillary tube far from the liquid inlet passes through the tube cap and extends to the bottom of the tube body. The output port of the injection pump is connected to one end of an air delivery capillary tube. The other end of the air delivery capillary tube passes through the tube cap and extends to the top of the tube body. The injection pump pumps out sterile filtered air, which is transmitted to the eluent sample tube through the air delivery capillary tube to increase the air pressure in the eluent sample tube, and pumps the eluent into the elution chip through the inlet capillary tube. In the final stage of the elution procedure, the injection pump continuously pumps out sterile air to displace the liquid in the inlet flow channel, the elution chamber, and the outlet flow channel into the eluent collection tube.

[0018] Optionally, the automatic microfluidic system further includes a chassis, a sample tube carrier, a collection tube carrier, and a capping mechanism. An installation hole is provided at the top of the chassis, and the chip carrier is disposed on the installation hole. The ultrasonic vibration mechanism and the syringe pump are both disposed inside the chassis. The sample tube carrier is disposed on one side of the chassis, and three eluent sample tubes are installed on the sample tube carrier. The touch-type industrial control computer is disposed on the other side of the chassis. The collection tube carrier is disposed on the top of the chassis, and the eluent collection tube is installed on the collection tube carrier. The capping mechanism is disposed on the top of the chassis and above the chip carrier. The capping mechanism is used to apply pressure to the sealing cap of the elution chip placed on the chip carrier, and fix the elution chip in the positioning groove.

[0019] According to another aspect of the present application, an elution method is provided, which uses the automatic microfluidic system as described above. The elution method includes the following steps:

[0020] S1. Load the elution chip into the positioning groove on the chip carrier, remove the sealing cap, horizontally place the plasmid DNA filter paper into the elution cavity through the opening, seal the opening with the sealing cap, install the eluent collection tube and the three eluent sample tubes with eluent in place, and connect the inlet capillary, the outlet capillary, and the syringe pump.

[0021] S2. Set the operating program through the touch-type industrial control computer, click start to start running the program. The syringe pump pumps sterile air into the three eluent sample tubes, and pushes a set amount of eluent into the elution chip to fill the elution cavity.

[0022] S3. Start the ultrasonic vibration mechanism. The ultrasonic probe emits ultrasonic waves with a set power for 4 seconds, and then stops.

[0023] S4. The syringe pump pumps sterile air into the three eluent sample tubes, and pushes one-third of the remaining eluent in the eluent sample tubes into the elution cavity.

[0024] S5. Start the ultrasonic vibration mechanism. The ultrasonic probe emits ultrasonic waves with a set power for 4 seconds, and then stops.

[0025] S6. The syringe pump pumps sterile air into the three eluent sample tubes, and pushes one-half of the remaining eluent in the eluent sample tubes into the elution cavity.

[0026] S7. Start the ultrasonic vibration mechanism. The ultrasonic probe emits ultrasonic waves with a set power for 4 seconds, and then stops.

[0027] S8. The injection pump pumps sterile air into the three eluent sample tubes, pushing the remaining eluent in the eluent sample tubes into the elution chamber. Then the injection pump continues to operate for 10 seconds until all the liquid in the liquid inlet channel, the elution chamber, and the liquid outlet channel is pushed into the eluent collection tube, completing the plasmid DNA filter paper elution process.

[0028] The beneficial effects of the plasmid DNA filter paper elution assembly, the automatic microfluidic system, and the elution method provided by this application are as follows:

[0029] 1. The plasmid DNA elution is completed inside the sealed elution chip, avoiding environmental pollution;

[0030] 2. In cooperation with the ultrasonic vibration mechanism, the plasmid DNA filter paper is thoroughly eluted, with high recovery rate, small mechanical damage, and short elution time;

[0031] 3. By using step-by-step ultrasound to accelerate the dissolution and diffusion of plasmid DNA, and cooperating with the injection pump to pump in a quantitative new eluent to replace the eluent in the elution chamber, the plasmid DNA filter paper drying, transportation, and storage technology is combined with the microfluidic technology. There is no cumbersome centrifugation step, the structure is simple, the operation is convenient, labor is saved, the plasmid DNA filter paper elution process is standardized, meeting the rapid experiment requirements of the laboratory, and truly realizing high-efficiency and high-quality plasmid DNA filter paper elution. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Among them:

[0034] Figure 1 is the assembly schematic diagram of the plasmid DNA filter paper elution assembly shown in an embodiment of this application;

[0035] Figure 2 is Figure 1 the perspective schematic diagram of the plasmid DNA filter paper elution assembly shown;

[0036] Figure 3 is Figure 1 the exploded schematic diagram of the plasmid DNA filter paper elution assembly shown;

[0037] Figure 4 is the external schematic diagram of the elution chip in the plasmid DNA filter paper elution assembly shown in an embodiment of this application;

[0038] Figure 5 is Figure 4 a perspective schematic view of the elution chip shown;

[0039] Figure 6 is Figure 4 an exploded schematic view of the elution chip shown;

[0040] Figure 7 a schematic structural view of the closing cover in the elution chip shown in an embodiment of the present application;

[0041] Figure 8 an external schematic view of the ultrasonic vibration mechanism in the plasmid DNA filter paper elution assembly shown in an embodiment of the present application;

[0042] Figure 9 is Figure 8 a perspective schematic view of the ultrasonic vibration mechanism shown;

[0043] Figure 10 is Figure 8 an exploded schematic view of the ultrasonic vibration mechanism shown;

[0044] Figure 11 a schematic structural view of the automatic microfluidic system shown in an embodiment of the present application;

[0045] Figure 12 is Figure 11 a schematic structural view of the automatic microfluidic system from another perspective shown;

[0046] Figure 13 an external schematic view of the automatic microfluidic system with a chassis, a sample tube carrier seat and a capping mechanism shown in an embodiment of the present application;

[0047] Figure 14 is Figure 13 a schematic structural view of the automatic microfluidic system from another perspective shown;

[0048] Figure 15 is Figure 13 a schematic view of the capping mechanism and the collection tube carrier seat in the automatic microfluidic system in an open state shown;

[0049] Figure 16 is Figure 13 a top view of the automatic microfluidic system shown;

[0050] Figure 17 a schematic structural view of the collection tube carrier seat in the closed state in the automatic microfluidic system shown in an embodiment of the present application;

[0051] Figure 18 a schematic structural view of the collection tube carrier seat in the open state in the automatic microfluidic system shown in an embodiment of the present application;

[0052] Figure 19 Explosion schematic diagram of the collection tube carrier in the automatic microfluidic system shown in an embodiment of the present application;

[0053] Figure 20 Partial structural schematic diagram of the gland mechanism in the automatic microfluidic system shown in an embodiment of the present application;

[0054] Figure 21 is Figure 20 Perspective view of the partial gland mechanism shown;

[0055] Figure 22 is Figure 20 Explosion diagram of the partial gland mechanism shown;

[0056] Figure 23 Elution fluid simulation trace velocity diagram in the elution chip;

[0057] Figure 24 Flow schematic diagram of the elution method shown in an embodiment of the present application;

[0058] Figure 25 Column chart of the concentrations of each group of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid samples;

[0059] Figure 26 Column chart of the supercoiled ratios of each group of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid samples;

[0060] Figure 27 Column chart of the plasmid concentration CV values of each group of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid samples;

[0061] Figure 28 Column chart of the recovery rates of each group of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid samples.

[0062] Description of main component symbols:

[0063] 1. Chassis; 2. Touch industrial computer; 3. Elution fluid sample tube; 4. Elution fluid collection tube;

[0064] 11. Elution chip; 111. Bottom sealing plate; 112. Substrate; 113. Sealing cover; 1101. Liquid inlet; 1102. Liquid outlet; 1103. Liquid inlet flow channel; 1104. Liquid outlet flow channel; 1106. Elution chamber; 1131. Silicone coating; 1132. Cover body; 1133. Plunger;

[0065] 21. Chip carrier;

[0066] 22. Ultrasonic vibration mechanism; 2201. Water inlet connector; 2202. Water outlet connector; 2203. Water bag; 2204. Ultrasonic probe;

[0067] 5. Pressing cover mechanism; 50. Limit seat; 51. Limit track; 52. Pressing cover long slider; 53. Hand-tightening screw; 54. First slider limit screw; 55. Second slider limit screw; 56. Pressing cover nut; 57. Connecting bolt;

[0068] 6. Collection tube carrier; 61. Carrier frame; 62. Pin; 63. Movable joint plate; 64. Capillary connector;

[0069] 71. Centrifugal water pump; 72. Heat dissipation module;

[0070] 301. Syringe pump;

[0071] 401. Liquid inlet capillary; 402. Liquid outlet capillary;

[0072] 8011. Gas transmission capillary. Detailed implementation manners

[0073] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0074] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0075] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0076] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more, unless otherwise specifically defined.

[0077] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application pertains. The terms used in the description of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0078] It should also be noted that in the embodiments of the present application, the same reference numerals are used to represent the same components or the same parts. For the same parts in the embodiments of the present application, only one of the parts or components may be marked with a reference numeral in the drawings. It should be understood that the reference numerals are equally applicable to other identical parts or components.

[0079] It can be understood that the plasmid DNA filter paper elution assembly, the automatic microfluidic system and the elution method provided by the present application are used for eluting plasmid DNA from the filter paper. For plasmid DNA filter papers for transportation or dry storage, if it is necessary to elute the plasmid DNA on the filter paper for experimental research, then this plasmid DNA filter paper elution assembly, automatic microfluidic system and elution method can be adopted.

[0080] Such as Figures 1-6 and Figures 8-9As shown in the figure, an embodiment of the present application provides a plasmid DNA filter paper elution assembly, which includes an elution chip 11, a chip carrier 21, and an ultrasonic vibration mechanism 22. The elution chip 11 includes a chip body and a sealing cover 113. An elution chamber 1106, three liquid inlet channels 1103 communicating with the elution chamber 1106, and three liquid outlet channels 1104 are provided in the chip body. An opening, three liquid inlets 1101, and one liquid outlet 1102 are provided on the upper surface of the chip body. The opening corresponds to and communicates with the elution chamber 1106 for placing a filter paper containing plasmid DNA. The sealing cover 113 is used to seal the opening. The three liquid inlets 1101 respectively communicate with one end of the three liquid inlet channels 1103 far from the elution chamber 1106 in a one-to-one correspondence, and the liquid outlet 1102 communicates with one end of the three liquid outlet channels 1104 far from the elution chamber 1106. A positioning groove for placing the elution chip 11 is provided at the top of the chip carrier 21. A through hole penetrating the chip carrier 21 up and down is provided at the bottom of the positioning groove. After the elution chip 11 is placed in the positioning groove, the elution chamber 1106 is located above the through hole. The ultrasonic vibration mechanism 22 includes a water bag 2203 and an ultrasonic probe 2204 disposed in the water bag 2203. The water bag 2203 extends into the positioning groove through the through hole, and the water bag 2203 is used to fit the position of the chip body corresponding to the elution chamber 1106.

[0081] In the embodiment of the present application, when using this plasmid DNA filter paper elution assembly for plasmid DNA filter paper elution, the plasmid DNA elution is completed inside the sealed chip, avoiding environmental pollution. At the same time, due to the ultrasonic acceleration of the ultrasonic vibration mechanism 22 for plasmid DNA dissolution and diffusion, the plasmid DNA filter paper elution is thorough, with high recovery rate, small mechanical damage, short elution time, and the whole process can be completed within a maximum of 3 minutes.

[0082] Furthermore, the size of the positioning groove on the chip carrier 21 is approximately the same as the size of the elution chip 11. The positioning groove can just horizontally place the elution chip 11. A side opening is provided at the edge of the positioning groove, and the elution chip 11 can be grasped by hand and placed into or taken out of the positioning groove.

[0083] In one embodiment, as Figures 4-6 shown, the chip body includes a bottom sealing plate 111 and a substrate 112 that are mutually attached. The elution chamber 1106, the three liquid inlet channels 1103, and the three liquid outlet channels 1104 are all provided between the bottom sealing plate 111 and the substrate 112. The opening, the three liquid inlets 1101, and the one liquid outlet 1102 are all provided on the side of the substrate 112 facing away from the bottom sealing plate 111.

[0084] In one embodiment, as Figure 5As shown, the elution chamber 1106 has a planar chamber wall arranged opposite to each other and an arcuate chamber wall protruding away from the planar chamber wall. Three liquid inlet channels 1103 communicate with the planar chamber wall, and three liquid outlet channels 1104 communicate with the arcuate chamber wall. The direction in which one of the liquid inlet channels 1103 accesses the elution chamber 1106 is perpendicular to the planar chamber wall, the directions in which the other two liquid inlet channels 1103 access the elution chamber 1106 are perpendicular to each other, and the directions in which the three liquid inlet channels 1103 access the elution chamber 1106 intersect at the center of the elution chamber 1106.

[0085] With the above settings, the inner surface of the chamber connected to the liquid outlet channel 1104 is in a shape of a converging angle, which is beneficial to completely push out all the liquid in the elution chamber 1106 with air.

[0086] As Figure 23 shown, the elution fluid simulation trace velocity of the elution chip 11 is shown. The elution fluid enters the elution chamber 1106 from three liquid inlets 1101 through three liquid inlet channels 1103. The flow rate of the elution fluid in the three liquid inlet channels 1103 is approximately the same, with no significant difference. When the elution fluid enters the elution chamber 1106, the flow rate of the elution fluid significantly decreases. Among them, the elution fluid traces entering the elution chamber 1106 through the upper and lower liquid inlets 1101 significantly spread. Compared with the elution fluid trace entering the elution chamber 1106 from the middle liquid inlet 1101, the originally concentrated beam of traces is dispersed into three traces, achieving full coverage of the plasmid DNA filter paper. The area of the plasmid DNA filter paper that can be rinsed is larger than that of the three parallel traces. The inner surface of the chamber where the elution chamber 1106 is connected to the three liquid inlet channels 1103 and the liquid outlet channels 1104 is in a shape of a converging angle. From the simulation results, it shows that the flow rate of the elution fluid in the three liquid outlet channels 1104 is approximately the same as the flow rate of the elution fluid in the three liquid inlet channels 1103, indicating that the flow rate of the liquid entering and leaving the chip per unit time is in an equal relationship.

[0087] In one embodiment, as Figures 2-3 shown, the aperture diameter of the through hole gradually decreases from the end far away from the positioning groove to the end close to the positioning groove. The water bag 2203 is in a frustum shape adapted to the shape of the through hole. The shape of the through hole can just wrap the frustum-shaped water bag 2203. The top of the water bag 2203 is in close fit with the bottom of the elution chip 11 at the position of the elution chamber 1106. With this design, the cooperation between the water bag 2203 and the ultrasonic probe 2204 can better apply ultrasonic vibration to the filter paper containing plasmid DNA in the elution chamber 1106 during the elution process.

[0088] In one embodiment, as Figures 8-12As shown, the ultrasonic vibration mechanism 22 further includes a water cooling unit. The inside of the water bladder 2203 is filled with water. An inlet connector 2201 and an outlet connector 2202 are provided on the water bladder 2203. The inlet connector 2201 and the outlet connector 2202 are respectively connected to the outlet and inlet of the water cooling unit through water pipes. The water cooling unit cools the water in the water bladder 2203 by means of water circulation.

[0089] By providing the water cooling unit, it is possible to prevent the temperature of the ultrasonic probe 2204 from rising during operation and being transmitted to the elution chip 11 through water, causing chip deformation.

[0090] Specifically, the water cooling unit mainly consists of a centrifugal water pump 71 and a heat dissipation module 72 (including a cooling fan, a water tank, heat sinks, and a duct). The water tank is filled with water. The water tank is connected to the centrifugal water pump 71 through a silicone hose. The centrifugal water pump 71 is then connected to the inlet connector 2201 on the water bladder 2203 through a water pipe. The water in the water bladder 2203 returns to the water tank through the water pipe connected to the outlet connector 2202. After being air-cooled by the heat sink in the water tank, it is pumped into the water bladder 2203 by the centrifugal water pump 71 again to complete the water cooling cycle.

[0091] In one embodiment, as Figures 4-7 shown, the closing cover 113 includes a cover body 1132, a plunger 1133, and a silicone coating 1131. The plunger 1133 is provided on one side of the cover body 1132, and the diameter of the plunger 1133 is smaller than that of the cover body 1132. The silicone coating 1131 is provided on the side of the cover body 1132 facing the plunger 1133 and surrounds the plunger 1133. The plunger 1133 is used to block the opening, and the silicone coating 1131 is used to contact the periphery of the opening to play a sealing role.

[0092] The embodiment of the present application also provides an automatic microfluidic system. As Figures 11-12 shown, the automatic microfluidic system includes three eluent sample tubes 3, one eluent collection tube 4, an injection pump 301, a touch-type industrial control computer 2, and the plasmid DNA filter paper elution assembly in any of the above embodiments. Three inlet ports 1101 correspond to the three eluent sample tubes 3 respectively and are connected through inlet capillaries 401. The outlet port 1102 is connected to the eluent collection tube 4 through an outlet capillary 402. The injection pump 301 is used to pump sterile-filtered air into the three eluent sample tubes 3 to increase the air pressure in the eluent sample tubes 3, so as to pump the eluent in the eluent sample tubes 3 into the elution chamber 1106 and then flow into the eluent collection tube 4. The touch-type industrial control computer 2 is electrically connected to the injection pump 301 and the ultrasonic probe 2204.

[0093] Among them, the eluent is a liquid with a pH value greater than or equal to 7.0 but less than 9.0.

[0094] When eluting plasmid DNA filter paper using the automatic microfluidic system in this application, in combination with Figure 24 as shown, the elution method includes the following steps:

[0095] S1. Load the elution chip 11 into the positioning groove on the chip carrier 21, remove the sealing cover 113, horizontally place the plasmid DNA filter paper into the elution chamber 1106 through the opening, seal the opening with the sealing cover 113, install the elution liquid collection tube 4 and three elution liquid sample tubes 3 with elution liquid in place, and connect the liquid inlet capillary 401, the liquid outlet capillary 402, and the injection pump 301;

[0096] S2. Set the operating program through the touch industrial computer 2, click start to start running the program, and the injection pump 301 pumps sterile air into the three elution liquid sample tubes 3, pushing a set amount of elution liquid into the elution chip 11 and filling the elution chamber 1106;

[0097] S3. Start the ultrasonic vibration mechanism 22, and the ultrasonic probe 2204 emits ultrasonic waves with a set power for 4 seconds, and then stops;

[0098] S4. The injection pump 301 pumps sterile air into the three elution liquid sample tubes 3, pushing one-third of the remaining elution liquid in the elution liquid sample tubes 3 into the elution chamber 1106;

[0099] S5. Start the ultrasonic vibration mechanism 22, and the ultrasonic probe 2204 emits ultrasonic waves with a set power for 4 seconds, and then stops;

[0100] S6. The injection pump 301 pumps sterile air into the three elution liquid sample tubes 3, pushing one-half of the remaining elution liquid in the elution liquid sample tubes 3 into the elution chamber 1106;

[0101] S7. Start the ultrasonic vibration mechanism 22, and the ultrasonic probe 2204 emits ultrasonic waves with a set power for 4 seconds, and then stops;

[0102] S8. The injection pump 301 pumps sterile air into the three elution liquid sample tubes 3, pushing the remaining elution liquid in the elution liquid sample tubes 3 into the elution chamber 1106, and then the injection pump 301 continues to run for 10 seconds until all the liquid in the liquid inlet channel 1103, the elution chamber 1106, and the liquid outlet channel 1104 is pushed into the elution liquid collection tube 4, completing the elution process of the plasmid DNA filter paper.

[0103] It should be noted that the method uses gradual ultrasound to accelerate the dissolution and diffusion of plasmid DNA, and cooperates with the injection pump 301 to pump in a quantitative new eluent to replace the eluent in the elution chamber 1106, thereby combining the plasmid DNA filter paper drying, transportation and storage technology with the microfluidic technology. There are no cumbersome centrifugation steps, the structure is simple, the operation is easy, labor-saving, and the plasmid DNA filter paper elution process is standardized, which meets the laboratory's rapid experimental needs and truly realizes high-efficiency and high-quality plasmid DNA filter paper elution.

[0104] In addition, by setting the flow direction, flow rate and flow rate of the elution liquid of the corresponding elution chip 11, the plasmid DNA filter paper placed in the elution chamber 1106 is eluted according to the set step program; unattended, the elution is automatically completed under the set program, saving manpower. Compared with the plasmid DNA filter paper soaking method used in general laboratories to elute plasmid DNA, the use of the elution chip 11 to elute plasmid DNA can better ensure the stability of experimental results between batches.

[0105] The touch-type industrial computer 2 is mainly composed of a liquid crystal touch screen and an industrial control module, wherein the liquid crystal touch screen is responsible for inputting control instructions and displaying data, and the industrial control module is responsible for outputting data, receiving data, processing data, and storing data. You can click on the liquid crystal touch screen, log in according to your account and password, set the program running plan, add or remove steps in the plan, and view the pressure value, flow rate, actual running time and other parameters of the injection pump 301, and form a table for viewing or transmitting to the network cloud for storage.

[0106] Specifically, the control interface of the touch-type industrial computer 2 can be logged in according to the account and password. The account has different levels of authorization levels, which correspond to the use and management permissions of the equipment that the corresponding operators can have, and can also track the use of the equipment; after logging in to the control system, you can select a program plan or create a new plan; after selecting a plan, click the OK button to enter the detailed configuration interface of the plan, in which you can set parameters for the flow rate, working time, flow rate and pressure threshold of the injection pump 301, and you can set parameters for the number of working times, working time, interval time and ultrasonic power of the ultrasonic probe 2204; the plan executes the program according to different stages, and the plan can be adjusted by adding or subtracting stages. The execution order of each stage can also be adjusted, and the working parameters of each injection pump 301 and ultrasonic probe 2204 in each stage can be adjusted.

[0107] In one embodiment, if Figures 11-12As shown, the eluent sample tube 3 includes a tube body and a tube cap detachably disposed on the tube body. One end of the liquid inlet capillary 401 away from the liquid inlet 1101 passes through the tube cap and extends to the bottom of the tube body. The output port of the injection pump 301 is connected to one end of the gas transmission capillary 8011. The other end of the gas transmission capillary 8011 passes through the tube cap and extends to the top of the tube body. The injection pump 301 pumps out sterile-filtered air, which is transmitted into the eluent sample tube 3 through the gas transmission capillary 8011, increasing the air pressure in the eluent sample tube 3, and pumping the eluent into the elution chip 11 through the liquid inlet capillary 401. In the final stage of the elution program, the injection pump 301 continuously pumps out sterile air, using the air to displace the liquid in the liquid inlet flow channel 1103, the elution chamber 1106, and the liquid outlet flow channel 1104 into the eluent collection tube 4.

[0108] In one embodiment, as Figures 13-16 shown, the automatic microfluidic system further includes a chassis 1, a sample tube carrier, a collection tube carrier 6, and a capping mechanism 5. The chassis 1 undertakes the loading function of each part and assembly of the automatic microfluidic system, provides protection for each part and assembly against external physical collisions, and a positioning and assembly space for necessary other related auxiliary units. There are mounting holes on the top of the chassis 1. The chip carrier 21 is disposed on the mounting holes. The ultrasonic vibration mechanism 22 and the injection pump 301 are both disposed inside the chassis 1. The sample tube carrier is disposed on one side of the chassis 1. Three eluent sample tubes 3 are installed on the sample tube carrier. The touch industrial computer 2 is disposed on the other side of the chassis 1. The collection tube carrier 6 is disposed on the top of the chassis 1. The eluent collection tube 4 is installed on the collection tube carrier 6. The capping mechanism 5 is disposed on the top of the chassis 1 and above the chip carrier 21. The capping mechanism 5 is used to apply pressure to the closing cap 113 of the elution chip 11 placed on the chip carrier 21 to fix the elution chip 11 in the positioning groove.

[0109] Specifically, there are three slots for inserting three eluent sample tubes 3 on the sample tube carrier. The three eluent sample tubes 3 are respectively inserted and fixed in the three slots in one-to-one correspondence.

[0110] As Figures 17-19As shown, the collection tube carrier seat 6 includes a carrier frame 61, a dowel pin 62, a movable joint plate 63, and a capillary joint 64. The carrier frame 61 and the movable joint plate 63 are rotationally connected by the dowel pin 62. There is a perforation at the end of the movable joint plate 63. One end of the capillary joint 64 passes through the movable joint plate 63. The carrier frame 61 has a round hole, and the elution liquid collection tube 4 can be vertically placed into it. The end of the capillary joint 64 passing through the movable joint plate 63 can be inserted into the elution liquid collection tube 4 in a vertical state. The other end of the capillary joint 64 is connected to the liquid outlet 1102 of the elution chip 11 through the liquid outlet capillary 402. The movable joint plate 63 of the carrier seat can rotate around the dowel pin 62 connected to the carrier frame 61, and the included angle with the horizontal plane ranges from 0° to less than 120°. When the included angle between the movable joint plate 63 and the horizontal plane is 0° (as shown in Figure 17 ), one end of the capillary joint 64 passing through the movable joint plate 63 is vertically inserted into the elution liquid collection tube 4. When the included angle between the movable joint plate 63 and the horizontal plane is 90° (as shown in Figure 18 ), one end of the capillary joint 64 passing through the movable joint plate 63 leaves the elution liquid collection tube 4, and the elution liquid collection tube 4 can be taken out from the round hole of the carrier frame 61 for standby.

[0111] Such as Figure 13 , Figure 15 , Figures 20-22As shown in the figure, the gland pressing mechanism 5 includes a limit seat 50 with a notch, a limit track 51, a gland pressing long strip slider 52, a hand-tightening screw 53, and a gland pressing nut 56. The limit track 51 and the limit seat 50 are respectively arranged on the chassis 1 on opposite sides of the bearing seat. The gland pressing long strip slider 52 is inserted into the limit track 51 and can move linearly in the limit track 51. The limit track 51 can limit the gland pressing long strip slider 52 within a certain range in the X-axis direction, Y-axis direction, and Z-axis direction of the Cartesian rectangular coordinate system. The gland pressing long strip slider 52 can move within a certain range in the X-axis direction. There is a threaded hole on the part of the outer section of the gland pressing long strip slider 52 in the limit track 51. The hand-tightening screw 53 is screwed in, passing through the gland pressing long strip slider 52 from top to bottom. The bottom of the end of the hand-tightening screw 53 is connected to the gland pressing nut 56 through a connecting bolt 57. The gland pressing nut 56 is embedded in the hexagonal groove at the corresponding position. When the hand-tightening screw 53 is turned, the gland pressing nut 56 can move along the Z-axis direction of the Cartesian rectangular coordinate system. The bottom of the gland pressing nut 56 can tightly press the sealing cover 113 of the elution chip 11, applying pressure to the sealing cover 113 to achieve the sealing of the elution cavity 1106. A through long groove is opened on the side of the limit track 51. The first slider limit screw 54 and the second slider limit screw 55 pass through the long groove and are connected to the side of the gland pressing long strip slider 52. Through these two limit screws, the gland pressing long strip slider 52 can be toggled to move along the X-axis direction of the Cartesian rectangular coordinate system. The end of the gland pressing long strip slider 52 close to the hand-tightening screw 53 can be inserted into the notch of the limit seat 50 to achieve the limit of the gland pressing long strip slider 52 in the X-axis direction, Y-axis, and Z-axis directions of the Cartesian rectangular coordinate system.

[0112] Embodiment

[0113] Two kinds of plasmid DNAs were respectively carried on fast type 101, medium speed type 102, and slow speed type 103 filter papers, and then the plasmid DNAs were respectively eluted by the elution chip 11 in the embodiment of the present application and the commonly used soaking method in general laboratories. The two plasmid DNAs were pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201, with lengths of 6712bp and 11472bp respectively. The operation steps for eluting plasmid DNA by the filter paper soaking method were as follows: a circle with a diameter of 0.4 cm was drawn on the sterilized filter paper with a pencil, 500 µL of plasmid DNA was spotted inside the circle, and after natural drying, it was placed in a self-sealing bag. After 72 hours, the filter paper with the drawn circle was cut out and placed in a 1.5 mL sample tube, 500 µL of TE solution was added to dissolve it, and it was left standing at room temperature for 30 minutes and then centrifuged at 10,000 rpm for 5 minutes, and the supernatant solution was aspirated for subsequent detection experiments.

[0114] The concentrations, A260 / A280 purities, and supercoiled ratios of the chip eluate, filter paper soak solution, and plasmid DNA stock solution were respectively detected by agarose gel electrophoresis. The recovery rate was calculated by the ratio of the chip eluate, filter paper soak solution to the plasmid DNA stock solution, and the coefficient of variation (CV) between batches of each sample was calculated by (standard deviation ÷ mean) × 100% = CV. The values were retained to three decimal places and expressed as mean ± standard deviation, i.e., mean ± SD. SPSS 11.0 was used for data analysis, and one-way ANOVA was used for comparison between groups.

[0115] As Figure 25 shown, the comparison of the concentrations of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA samples in each group showed that for the filter paper model Fast 101, there were significant differences in the concentration values of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA eluted by the chip elution and soaking methods, P < 0.05. The plasmid DNA concentrations in the chip eluate of the two plasmid DNAs were 1.825 times and 1.949 times that of the filter paper soak solution respectively; for the filter paper model Medium 102, there were significant differences in the concentration values of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA eluted by the chip elution and soaking methods, P < 0.05. The plasmid DNA concentrations in the chip eluate of the two plasmid DNAs were 1.839 times and 1.942 times that of the filter paper soak solution respectively; for the filter paper model Slow 103, there were significant differences in the concentration values of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA eluted by the chip elution and soaking methods, P < 0.05. The plasmid DNA concentrations in the chip eluate of the two plasmid DNAs were 2.002 times and 2.164 times that of the filter paper soak solution respectively; the concentration comparison results showed that whether it was plasmid DNA with a molecular weight less than 10,000 bp or greater than 10,000 bp, plasmid DNA elution using the elution chip 11 in combination with the automatic microfluidic system could obtain a concentration similar to that of the plasmid DNA stock solution, while there was a disadvantage of low elution concentration when using the soaking method to elute the filter paper, demonstrating the high efficiency of the elution chip 11.

[0116] As Figure 26As shown, the comparison of the supercoiled ratios of each group of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA samples shows that for filter paper model Fast 101, there are significant differences in the supercoiled ratios of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA eluted by chip elution and soaking method, P<0.05. The supercoiled ratios of plasmid DNA in the chip eluents of the two plasmid DNAs are 1.245 times and 1.291 times that of the filter paper soaking solution respectively; for filter paper model Medium 102, there are significant differences in the supercoiled ratios of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA eluted by chip elution and soaking method, P<0.05. The supercoiled ratios of plasmid DNA in the chip eluents of the two plasmid DNAs are 1.305 times and 1.360 times that of the filter paper soaking solution respectively; for filter paper model Slow 103, there are significant differences in the supercoiled ratios of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA eluted by chip elution and soaking method, P<0.05. The supercoiled ratios of plasmid DNA in the chip eluents of the two plasmid DNAs are 1.400 times and 1.414 times that of the filter paper soaking solution respectively; the comparison results of the supercoiled ratios show that whether it is plasmid DNA with a molecular weight less than 10000bp or greater than 10000bp, using elution chip 11 in combination with an automatic microfluidic system for plasmid DNA elution can obtain a supercoiled ratio that is almost the same as that of the plasmid DNA stock solution, while using the filter paper soaking method shows a trend of decreasing supercoiled ratio to varying degrees, indicating that using the soaking method to elute plasmid DNA causes certain mechanical damage to the plasmid DNA. The comparison results show the high efficiency of elution chip 11.

[0117] As Figure 27As shown, the comparison of the CV values of each group of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA samples shows that for filter paper model Quick 101, when pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA are eluted by chip elution and soaking methods, the CV values of the filter paper soaking solution are 9.633 times and 4.297 times that of the chip elution solution of the two plasmid DNAs respectively; the comparison of the CV values of each group of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA samples shows that for filter paper model Medium 102, when pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA are eluted by chip elution and soaking methods, the CV values of the filter paper soaking solution are 5.406 times and 5.336 times that of the chip elution solution of the two plasmid DNAs respectively; the comparison of the CV values of each group of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA samples shows that for filter paper model Slow 103, when pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA are eluted by chip elution and soaking methods, the CV values of the filter paper soaking solution are 4.084 times and 7.120 times that of the chip elution solution of the two plasmid DNAs respectively; this comparison result indicates that the CV value is larger and the batch-to-batch coefficient of variation is larger when using the soaking method, showing that manual operation for eluting plasmid DNA cannot be standardized and unified, while using chip elution shows a small batch-to-batch coefficient of variation, and the quality of plasmid DNA eluted by the automatic microfluidic system is very consistent.

[0118] As Figure 28As shown, the comparison of the recovery rates of each group of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA samples shows that for filter paper model Quick 101, there are significant differences in the recovery rates of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA eluted by chip elution and soaking method, P<0.05. The plasmid DNA recovery rates of the chip eluents of the two plasmid DNAs are 1.825 times and 1.949 times that of the filter paper soaking solution respectively; for filter paper model Medium 102, there are significant differences in the recovery rates of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA eluted by chip elution and soaking method, P<0.05. The plasmid DNA recovery rates of the chip eluents of the two plasmid DNAs are 1.839 times and 1.942 times that of the filter paper soaking solution respectively; for filter paper model Slow 103, there are significant differences in the recovery rates of pET28b-T7-6×His-GST-EGFP-6×His and pCAMBIA3201 plasmid DNA eluted by chip elution and soaking method, P<0.05. The plasmid DNA recovery rates of the chip eluents of the two plasmid DNAs are 2.002 times and 2.164 times that of the filter paper soaking solution respectively; the comparison results of the recovery rates show that whether it is plasmid DNA with a molecular weight less than 10,000 bp or greater than 10,000 bp, the plasmid DNA eluted by using elution chip 11 in combination with an automatic microfluidic system is almost the same as the plasmid DNA stock solution, while the use of the filter paper soaking method shows a reduction in the recovery rate to varying degrees, indicating that the plasmid DNA elution by the soaking method is not complete. The comparison results show the high efficiency of elution chip 11.

[0119] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0120] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation to the scope of the application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A plasmid DNA filter paper elution component, characterized in that Comprising: An elution chip, including a chip body and a sealing cover. An elution chamber, three liquid inlet channels and three liquid outlet channels communicating with the elution chamber are provided in the chip body. An opening, three liquid inlets and one liquid outlet are provided on the upper surface of the chip body. The opening is correspondingly communicated with the elution chamber for placing a filter paper containing plasmid DNA. The sealing cover is used to seal the opening. The three liquid inlets are respectively and correspondingly communicated with one end of the three liquid inlet channels far away from the elution chamber. The liquid outlet is communicated with one end of the three liquid outlet channels far away from the elution chamber; A chip carrier, with a positioning groove for placing the elution chip provided at the top. A through hole penetrating the chip carrier up and down is provided at the bottom of the positioning groove. After the elution chip is placed in the positioning groove, the elution chamber is located above the through hole; and An ultrasonic vibration mechanism, including a water bag and an ultrasonic probe arranged in the water bag. The water bag extends into the positioning groove through the through hole. The water bag is used to fit the position of the chip body corresponding to the elution chamber.

2. The plasmid DNA filter paper elution assembly according to claim 1, wherein The chip body includes a bottom sealing plate and a substrate that are mutually attached. The elution chamber, the three liquid inlet channels and the three liquid outlet channels are all arranged between the bottom sealing plate and the substrate. The opening, the three liquid inlets and the one liquid outlet are all arranged on the side of the substrate facing away from the bottom sealing plate.

3. The plasmid DNA filter paper elution assembly according to claim 1, wherein The aperture of the through hole gradually decreases from the end far away from the positioning groove to the end close to the positioning groove. The water bag is in a frustum shape adapted to the shape of the through hole.

4. The plasmid DNA filter paper elution assembly according to claim 1, wherein The ultrasonic vibration mechanism further includes a water cooling unit. The inside of the water bag is filled with water. An inlet joint and an outlet joint are provided on the water bag. The inlet joint and the outlet joint are respectively connected to the outlet and inlet of the water cooling unit through water pipes. The water cooling unit cools the water in the water bag by means of water circulation.

5. The plasmid DNA filter paper elution assembly according to claim 1, wherein The elution chamber has a flat chamber wall arranged oppositely and an arc-shaped chamber wall protruding away from the flat chamber wall. The three liquid inlet channels are communicated with the flat chamber wall. The three liquid outlet channels are communicated with the arc-shaped chamber wall. The direction of one of the liquid inlet channels accessing the elution chamber is perpendicular to the flat chamber wall. The directions of the other two liquid inlet channels accessing the elution chamber are perpendicular to each other. The directions of the three liquid inlet channels accessing the elution chamber intersect at the center of the elution chamber.

6. The plasmid DNA filter paper elution assembly according to claim 1, wherein, The sealing cover includes a cover body, a plunger and a silica gel coating. The plunger is arranged on one side of the cover body, and the diameter of the plunger is smaller than that of the cover body. The silica gel coating is arranged on the side of the cover body facing the plunger and surrounds the plunger. The plunger is used to block the opening. The silica gel coating is used to contact the periphery of the opening to play a sealing role.

7. An automatic microfluidic system, characterized in that, Including three elution liquid sample tubes, one elution liquid collection tube, an injection pump, a touch-type industrial control computer and a plasmid DNA filter paper elution assembly according to any one of claims 1-6; The three inlet ports respectively correspond to the three eluent sample tubes one by one and are connected by inlet capillaries. The outlet is connected to the eluent collection tube by an outlet capillary. The injection pump is used to pump sterile-filtered air into the three eluent sample tubes to increase the air pressure in the eluent sample tubes, so as to pump the eluent in the eluent sample tubes into the elution chamber and then flow into the eluent collection tube. The touch industrial computer is electrically connected to the injection pump and the ultrasonic probe.

8. The automatic microfluidic system according to claim 7, wherein The eluent sample tube includes a tube body and a tube cap detachably arranged on the tube body. The end of the inlet capillary away from the inlet port passes through the tube cap and extends to the bottom of the tube body. The output port of the injection pump is connected to one end of an air delivery capillary. The other end of the air delivery capillary passes through the tube cap and extends to the top of the tube body. The injection pump pumps out sterile-filtered air, which is transmitted into the eluent sample tube through the air delivery capillary to increase the air pressure in the eluent sample tube, and pumps the eluent into the elution chip through the inlet capillary. In the final stage of the elution procedure, the injection pump continuously pumps out sterile air to displace the liquid in the inlet flow channel, the elution chamber and the outlet flow channel into the eluent collection tube.

9. The automatic microfluidic system according to claim 7, wherein The automatic microfluidic system further includes a chassis, a sample tube carrier, a collection tube carrier and a capping mechanism. The top of the chassis is provided with a mounting hole, and the chip carrier is arranged on the mounting hole. The ultrasonic vibration mechanism and the injection pump are both arranged in the chassis. The sample tube carrier is arranged on one side of the chassis. The three eluent sample tubes are installed on the sample tube carrier. The touch industrial computer is arranged on the other side of the chassis. The collection tube carrier is arranged on the top of the chassis. The eluent collection tube is installed on the collection tube carrier. The capping mechanism is arranged on the top of the chassis and above the chip carrier. The capping mechanism is used to apply pressure to the sealing cover of the elution chip placed on the chip carrier to fix the elution chip in the positioning groove.

10. An elution method, characterized in that, Using the automatic microfluidic system according to any one of claims 7-9, the elution method includes the following steps: S1. Load the elution chip into the positioning groove on the chip carrier, remove the sealing cover, horizontally place the plasmid DNA filter paper into the elution chamber through the opening, seal the opening with the sealing cover, install the eluent collection tube and the three eluent sample tubes with eluent in place, and connect the inlet capillary, the outlet capillary and the injection pump. S2. Set the operating program through the touch industrial computer, click start to start running the program. The injection pump pumps sterile air into the three eluent sample tubes to push a set amount of eluent into the elution chip and fill the elution chamber. S3. Start the ultrasonic vibration mechanism. The ultrasonic probe emits ultrasonic waves with a set power for 4 seconds and then stops. S4. The syringe pump pumps sterile air into the three eluent sample tubes, pushing one-third of the remaining eluent in the eluent sample tubes into the elution chamber; S5. Start the ultrasonic vibration mechanism, and the ultrasonic probe emits ultrasonic waves with a set power for 4 seconds and then stops; S6. The syringe pump pumps sterile air into the three eluent sample tubes, pushing one-half of the remaining eluent in the eluent sample tubes into the elution chamber; S7. Start the ultrasonic vibration mechanism, and the ultrasonic probe emits ultrasonic waves with a set power for 4 seconds and then stops; S8. The syringe pump pumps sterile air into the three eluent sample tubes, pushing the remaining eluent in the eluent sample tubes into the elution chamber, and then the syringe pump continues to operate for 10 seconds until all the liquid in the inlet flow channel, the elution chamber, and the outlet flow channel is pushed into the eluent collection tube, completing the plasmid DNA filter paper elution process.

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