Micro-droplet generation device and digital PCR detector

Abstract

The utility model discloses a micro-droplet generating device and a digital PCR (Polymerase Chain Reaction) detector, and relates to the technical field of nucleic acid detection. The micro-droplet generating device comprises an injection shell, a push rod, a needle head and an outer tube. The injection shell is provided with a push-pull channel and an oil inlet channel, the cross section of the oil inlet channel is annular, the oil inlet channel is arranged outside the push-pull channel in a surrounding mode, the oil inlet channel and the push-pull channel are coaxial and are arranged in a separated mode, the push rod is arranged in the push-pull channel in a sliding mode, the needle head and the outer pipe are detachably connected with the injection shell, the needle head is communicated with the push-pull channel, and the outer pipe is arranged outside the needle head in a sleeving mode. And an oil outlet channel is formed between the outer tube and the needle head and is communicated with the oil inlet channel. The micro-droplet generation device provided by the utility model can ensure that the proportions of original solutions in the water-in-oil micro-droplets are the same, the uniformity of the water-in-oil micro-droplets is improved, and the nucleic acid detection effect is ensured.

Description

Technical Field

[0001] This utility model relates to the field of nucleic acid detection technology, specifically to a microdroplet generation device and a digital PCR detector. Background Technology

[0002] Droplet digital PCR is an absolute quantitative PCR technique that primarily employs a dropletization method to disperse a solution containing the target nucleic acid into a large number of water-in-oil microdroplets, forming tens of thousands of independent microreaction systems of equal volume. Each droplet initially contains 0, 1, or more target nucleic acid templates. After PCR cycles, droplets initially containing one target nucleic acid will emit a fluorescent signal, while droplets without a target nucleic acid will not emit a fluorescent signal. Based on the relative proportions of the two types of droplets and Poisson distribution mathematical corrections, the concentration of the target nucleic acid in the original solution can be calculated.

[0003] Currently, the general method for preparing water-in-oil microdroplets involves mixing the original solution and oil in a certain ratio, then helically stirring the mixture before dripping it out at a specific flow rate to form water-in-oil microdroplets. However, this helical stirring method easily leads to uneven mixing of the original solution and oil, resulting in inconsistent proportions of the original solution in each water-in-oil microdroplet. This poor uniformity of the microdroplets directly affects the nucleic acid detection results.

[0004] Therefore, designing a microdroplet generation device with good uniformity and a digital PCR detector is particularly important, especially in nucleic acid detection. Utility Model Content

[0005] The purpose of this invention is to provide a microdroplet generation device that can ensure that the proportion of the original solution in each water-in-oil microdroplet is the same, thereby improving the uniformity of the water-in-oil microdroplets and ensuring the effectiveness of nucleic acid detection.

[0006] Another objective of this invention is to provide a digital PCR detector that ensures the same proportion of the original solution in each water-in-oil microdroplet, thereby improving the uniformity of the water-in-oil microdroplets and ensuring the effectiveness of nucleic acid detection.

[0007] This utility model is achieved by the following technical solution.

[0008] A microdroplet generating device includes an injection shell, a push rod, a needle, and an outer tube. The injection shell has a push-pull channel and an oil inlet channel. The oil inlet channel has an annular cross-section and surrounds the push-pull channel. The oil inlet channel and the push-pull channel are coaxial and separated. The push rod is slidably disposed within the push-pull channel. The oil inlet channel is used to allow flushing oil to enter. The needle and the outer tube are detachably connected to the injection shell. The needle communicates with the push-pull channel and is used to draw in the original solution when the push rod slides away from the needle. The outer tube is sleeved around the needle, and an oil outlet channel is formed between the outer tube and the needle. The oil outlet channel communicates with the oil inlet channel. The needle is also used to push out the original solution when the push rod slides towards the needle. The oil outlet channel is used to output flushing oil while the original solution is pushed out, so as to form water-in-oil microdroplets.

[0009] Optionally, the injection housing includes a syringe and a cannula, the cannula being connected to the syringe and fitted over the syringe, forming an oil inlet channel between the cannula and the syringe, a push-pull channel being provided inside the syringe, the needle being detachably connected to the syringe, and the outer tube being detachably connected to the cannula.

[0010] Optionally, the syringe includes a seat and an extension tube connected to each other, the extension tube being disposed in the middle of the seat, and a push-pull channel being disposed in both the seat and the extension tube; the cannula includes a connecting disc and a tube body connected to each other, the tube body being disposed in the middle of the connecting disc, both the connecting disc and the tube body being sleeved outside the extension tube, an oil inlet channel being disposed between the tube body and the extension tube, and the connecting disc being connected to the seat.

[0011] Optionally, the seat body has a first inlet, which is connected to the side wall of the push-pull channel and is used to supply and exhaust oil; the connecting plate has a second inlet, which is connected to the side wall of the oil inlet channel and is used to supply flushing oil.

[0012] Optionally, the end of the oil inlet channel away from the oil outlet channel has an end wall with a clearance hole. The extension tube passes through the clearance hole. The end wall is curved or inclined and gradually approaches the oil outlet channel in the flow direction of the flushing oil introduced from the second inlet.

[0013] Optionally, a limiting stage is provided inside the outer tube, and the needle includes a body part and a stepped part that are connected to each other. The stepped part is located at the end of the body part near the injection shell, and the limiting stage abuts against the stepped part.

[0014] Optionally, the stepped portion is provided with an oil drain hole for the flow of flushing oil.

[0015] Optionally, the end of the outer tube away from the injection housing is provided with a constricted section, and the constricted section is provided with a constricted inner wall and a straight inner wall in sequence. The end of the needle away from the injection housing is provided with a capillary tube, the capillary tube extending into the straight inner wall and being coaxially spaced with the straight inner wall.

[0016] Optionally, the microdroplet generating device further includes a drive mechanism connected to a push rod, the drive mechanism being used to drive the push rod to slide relative to the injection housing; and / or, the microdroplet generating device further includes an oil pump mechanism connected to an oil inlet channel, the oil pump mechanism being used to introduce flushing oil into the oil inlet channel.

[0017] A digital PCR detector includes the aforementioned microdroplet generating device. The device comprises an injection shell, a push rod, a needle, and an outer tube. The injection shell has a push-pull channel and an oil inlet channel. The oil inlet channel has an annular cross-section and surrounds the push-pull channel. The oil inlet channel and the push-pull channel are coaxial and separated. The push rod is slidably disposed within the push-pull channel. The oil inlet channel is used for the introduction of flushing oil. The needle and the outer tube are detachably connected to the injection shell. The needle communicates with the push-pull channel and is used to draw in the original solution when the push rod slides away from the needle. The outer tube is sleeved around the needle, forming an oil outlet channel between the outer tube and the needle. The oil outlet channel communicates with the oil inlet channel. The needle is also used to expel the original solution when the push rod slides towards the needle. The oil outlet channel is used to output flushing oil while the original solution is expelled, thereby forming water-in-oil microdroplets.

[0018] The microdroplet generation device and digital PCR detector provided by this invention have the following beneficial effects:

[0019] The microdroplet generating device provided by this utility model has an injection shell with a push-pull channel and an oil inlet channel. The cross-section of the oil inlet channel is annular and surrounds the push-pull channel. The oil inlet channel and the push-pull channel are coaxial and separated. The push rod is slidably disposed in the push-pull channel. The oil inlet channel is used to allow flushing oil to enter. The needle and the outer tube are detachably connected to the injection shell. The needle is connected to the push-pull channel and is used to draw in the original solution when the push rod slides away from the needle. The outer tube is sleeved on the outside of the needle, and an oil outlet channel is formed between the outer tube and the needle. The oil outlet channel is connected to the oil inlet channel. The needle is also used to push out the original solution when the push rod slides towards the needle. The oil outlet channel is used to output flushing oil while the original solution is pushed out, so as to form water-in-oil microdroplets. Compared with the prior art, the microdroplet generation device provided by this utility model adopts a coaxial and separated oil inlet channel and push-pull channel, as well as an outer tube sleeved outside the needle and forming an oil outlet channel with the needle. Therefore, it can ensure that the proportion of the original solution in each water-in-oil microdroplet is the same, improve the uniformity of the water-in-oil microdroplets, and ensure the nucleic acid detection effect.

[0020] The digital PCR detector provided by this invention includes a microdroplet generating device, which can ensure that the proportion of the original solution in each water-in-oil microdroplet is the same, improve the uniformity of the water-in-oil microdroplets, and ensure the nucleic acid detection effect. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the microdroplet generation device provided in the first embodiment of the present invention;

[0023] Figure 2 A cross-sectional view of the microdroplet generating device provided in the first embodiment of this utility model, in which the injection shell is simultaneously connected to the needle and the outer tube;

[0024] Figure 3 A cross-sectional view of the injection shell connected to both the needle and the outer tube in the microdroplet generating device provided in the first embodiment of this utility model.

[0025] Figure 4 A cross-sectional view of the sliding fit between the injection shell and the push rod in the microdroplet generation device provided in the first embodiment of this utility model;

[0026] Figure 5 A cross-sectional view of the outer tube sleeved outside the needle in the microdroplet generating device provided in the first embodiment of this utility model;

[0027] Figure 6 A cross-sectional view of the outer tube sleeved outside the needle in the microdroplet generating device provided in the first embodiment of this utility model;

[0028] Figure 7 This is a partial cross-sectional view of the injection shell in the microdroplet generation device provided in the second embodiment of this utility model.

[0029] Icons: 100-Microdroplet generating device; 110-Injection housing; 111-Push-pull channel; 112-Oil inlet channel; 1121-End wall; 1122-Displacement hole; 113-Syringe; 1131-Seat; 1132-Extension tube; 1133-First inlet; 1134-Assembly section; 114-Sleeve; 1141-Connecting plate; 1142-Tube body; 1143-Second inlet; 1144-Matching section; 120-Push rod; 130-Needle; 131-Main body; 132-Step section; 133-Oil leakage hole; 134-Capillary tube; 140-Outer tube; 141-Limiting platform; 142-Narrowing section; 143-Narrowing inner wall; 144-Straight inner wall; 150-Oil outlet channel; 160-Drive mechanism. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] In the description of this utility model, it should be noted that the terms "inner," "outer," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0034] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," "installed," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0035] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the features in the following embodiments can be combined with each other.

[0036] First Embodiment

[0037] Please refer to the reference. Figures 1 to 6This invention provides a digital PCR detector (not shown) for nucleic acid detection. It ensures that the proportion of the original solution in each water-in-oil microdroplet is the same, improving the uniformity of the water-in-oil microdroplets and guaranteeing the effectiveness of nucleic acid detection.

[0038] The digital PCR detector includes a microdroplet generation device 100, a temperature control device (not shown), and a microscope imaging device (not shown). The microdroplet generation device 100 generates a large number of water-in-oil microdroplets from the original solution of a sample and injects these microdroplets into a reaction pan placed on the temperature control device. The temperature control device cycles the temperature of these microdroplets through the reaction pan, doubling the number of target nucleic acids in each microdroplet with each cycle. This process is repeated to significantly increase the amount of target nucleic acids from a small quantity. The microscope imaging device photographs and measures all the microdroplets after the temperature cycles are completed. Microdroplets initially containing target nucleic acids emit fluorescence signals, while those without do not. Based on the relative proportions of the two types of microdroplets and a Poisson distribution correction, the concentration of the target nucleic acid in the original solution of the corresponding sample can be calculated.

[0039] The microdroplet generating device 100 includes an injection housing 110, a push rod 120, a needle 130, and an outer tube 140. The injection housing 110 is provided with a push-pull channel 111 and an oil inlet channel 112. The oil inlet channel 112 has an annular cross-section and surrounds the push-pull channel 111. The oil inlet channel 112 is coaxial with and separate from the push-pull channel 111, so that the oil inlet channel 112 and the push-pull channel 111 are independent and do not affect each other. The oil inlet channel 112 is used to supply flushing oil. Specifically, the push rod 120 is slidably disposed within the push-pull channel 111. The push rod 120 can slide relative to the push-pull channel 111 to create negative or positive pressure within the push-pull channel 111, thereby achieving liquid absorption and dripping functions. The push-pull channel 111 can guide and limit the push rod 120. Both the needle 130 and the outer tube 140 are detachably connected to the injection housing 110. The needle 130 communicates with the push-pull channel 111 and is used to draw in the original solution when the push rod 120 slides away from the needle 130. The outer tube 140 is sleeved over the needle 130, and an oil outlet channel 150 is formed between the outer tube 140 and the needle 130. The oil outlet channel 150 communicates with the oil inlet channel 112, and the flushing oil in the oil inlet channel 112 can flow smoothly to the oil outlet channel 150. The needle 130 is also used to push out the original solution when the push rod 120 slides towards the needle 130. The oil outlet channel 150 is used to output flushing oil while the original solution is pushed out, so as to form water-in-oil microdroplets. In this way, through the limiting effect of the needle 130 and the outer tube 140, and by reasonably controlling the flow rate of the original solution and the flushing oil, the original solution and the flushing oil can be stably discharged from the microdroplet generating device 100 at the same time (the original solution flows out from the needle 130, and the flushing oil flows out from the oil outlet channel 150), forming water-in-oil microdroplets. This ensures that the proportion of the original solution in each water-in-oil microdroplet is the same, improves the uniformity of the water-in-oil microdroplets, and ensures the effect of nucleic acid detection.

[0040] Furthermore, during the use of the microdroplet generating device 100, the air in the push-pull channel 111 and the needle 130 is first eliminated; then a certain amount of the original solution is drawn through the needle 130; next, the original solution flows out from the needle 130 under the pressure of the push rod 120, forming microdroplets. During this process, the flushing oil enters the oil inlet channel 112 evenly under the action of external force and flows out through the oil outlet channel 150 to flush the microdroplets located at the end of the needle 130; when the force of the flushing oil (flushing force) is greater than the surface tension of the microdroplet, the microdroplet falls off from the end of the needle 130 and flows into the reaction plate below with the flushing oil, thus forming microdroplets of the original solution (i.e., water-in-oil microdroplets) wrapped in flushing oil. Specifically, as long as the flow rates of the original solution and the flushing oil are uniform (the two liquids have different flow rates), uniform water-in-oil microdroplets can be formed. The size of the water-in-oil microdroplets is affected by the flow rates and physical properties (viscosity and density, etc.) of the two liquids. If water-in-oil microdroplets of different sizes are to be generated, the flow rates and composition ratios of the two liquids need to be adjusted.

[0041] It should be noted that both the needle 130 and the outer tube 140 are consumables. During the dripping process, the needle 130 must first be installed on the injection housing 110 so that the needle 130 is connected to the push-pull channel 111; then the needle 130 is inserted into the sample solution storage tube to draw the original solution in the sample solution storage tube into the needle 130 (the amount drawn is very small, about 20 μL, so the original solution will not enter the injection housing 110); next, the outer tube 140 is installed on the injection housing 110 so that the outer tube 140 is spaced around the needle 130 and forms an oil outlet channel 150 between the outer tube and the needle 130; then the original solution is dripped out, and flushing oil is simultaneously introduced into the oil inlet channel 112 so that the flushing oil flows out from the oil outlet channel 150 and coats the original solution microdroplets to form water-in-oil microdroplets. In this way, during each drip, only the needle 130 and the outer tube 140 come into contact with the original solution of the sample. To avoid cross-contamination of multiple samples, after each drip, the used needle 130 and outer tube 140 need to be removed and replaced with new needle 130 and outer tube 140 to facilitate the next drip.

[0042] The injection housing 110 includes a syringe 113 and a cannula 114. The cannula 114 is connected to the syringe 113 and is sleeved over the syringe 113. An annular oil inlet channel 112 is formed between the cannula 114 and the syringe 113. A push-pull channel 111 is disposed inside the syringe 113 so that the oil inlet channel 112 surrounds the push-pull channel 111. Specifically, the needle 130 is detachably connected to the syringe 113 so that the needle 130 communicates with the push-pull channel 111; the outer tube 140 is detachably connected to the cannula 114 so that the oil outlet channel 150 communicates with the oil inlet channel 112. In this way, the needle 130 and the outer tube 140 can be independently assembled and disassembled, which is convenient and practical.

[0043] The syringe 113 includes a base 1131 and an extension tube 1132 connected to each other. In this embodiment, the base 1131 and the extension tube 1132 are integrally formed to improve the connection strength. The extension tube 1132 is disposed in the middle of the base 1131, and a push-pull channel 111 is disposed in both the base 1131 and the extension tube 1132. A push rod 120 extends from the end of the base 1131 away from the extension tube 1132 into the push-pull channel 111 and can slide within the push-pull channel 111 to create a negative or positive pressure within the push-pull channel 111.

[0044] The cannula 114 includes a connecting disc 1141 and a tube body 1142 connected to each other. In this embodiment, the connecting disc 1141 and the tube body 1142 are integrally formed to improve the connection strength. The tube body 1142 is disposed in the middle of the connecting disc 1141. Both the connecting disc 1141 and the tube body 1142 are sleeved on the extension tube 1132, that is, the extension tube 1132 passes through the connecting disc 1141 and the tube body 1142 in sequence. Specifically, the connecting disc 1141 and the extension tube 1132 are sealed together, that is, there is no gap between the connecting disc 1141 and the extension tube 1132. The oil inlet channel 112 is disposed between the tube body 1142 and the extension tube 1132 to prevent the flushing oil from flowing away from the oil outlet channel 150. The connecting disc 1141 is connected to the seat 1131 to fix the relative position of the syringe 113 and the cannula 114, preventing the cannula 114 from rotating or displacing relative to the syringe 113.

[0045] Preferably, the seat 1131 has a first inlet 1133, which is connected to the side wall of the push-pull channel 111. The first inlet 1133 is used to supply and release exhaust oil. The exhaust oil is used to pass through the push-pull channel 111 and the needle 130 before the actual dripping, so as to remove the air in the push-pull channel 111 and the needle 130 and ensure the dripping effect.

[0046] Preferably, the connecting plate 1141 has a second inlet 1143, which is connected to the side wall of the oil inlet channel 112. The second inlet 1143 is used to supply flushing oil, which is used to flush the tiny droplets located at the end of the needle 130 to form original solution droplets (i.e., water-in-oil droplets) wrapped in flushing oil.

[0047] It should be noted that exhaust oil and flushing oil have exactly the same composition and ratio. The difference in name is only for ease of understanding. In essence, they are both combinations of mineral oil and some chemical solvents.

[0048] Furthermore, the end of the oil inlet channel 112 away from the oil outlet channel 150 has an end wall 1121, and the end wall 1121 has a clearance hole 1122. The extension tube 1132 is disposed through the clearance hole 1122, and the extension tube 1132 and the clearance hole 1122 are tightly fitted together. There is no gap between the inner wall of the extension tube 1132 and the clearance hole 1122 to prevent the flushing oil from flowing away from the oil outlet channel 150. In this embodiment, the end wall 1121 is set horizontally, and the second inlet 1143 is set close to the end wall 1121. The flushing oil entering the oil inlet channel 112 through the second inlet 1143 can flow stably towards the oil outlet channel 150 under the blocking action of the end wall 1121.

[0049] In this embodiment, an assembly section 1134 is provided at the end of the extension tube 1132 away from the base 1131. The assembly section 1134 protrudes from the tube body 1142. The needle 130 is sleeved on the assembly section 1134 and snapped into the assembly section 1134 to realize the detachable connection between the needle 130 and the extension tube 1132, which is convenient for disassembly and assembly, and can ensure the sealing of the connection between the needle 130 and the push-pull channel 111.

[0050] In this embodiment, a mating section 1144 is provided at the end of the pipe body 1142 away from the connecting plate 1141. The outer pipe 140 is sleeved on the mating section 1144 and snapped into the mating section 1144 to realize the detachable connection between the outer pipe 140 and the pipe body 1142, which is convenient for disassembly and assembly, and can ensure the sealing of the connection between the oil outlet channel 150 and the oil inlet channel 112.

[0051] Preferably, a limiting platform 141 is provided inside the outer tube 140, and the needle 130 includes a body portion 131 and a stepped portion 132 connected to each other. The stepped portion 132 is located at one end of the body portion 131 near the injection housing 110. The limiting platform 141 abuts against the stepped portion 132, and the limiting platform 141 can limit the stepped portion 132 to limit the entire needle 130, preventing the needle 130 from disengaging from the extension tube 1132 and ensuring the stability of the engagement between the needle 130 and the extension tube 1132. Specifically, both the limiting platform 141 and the stepped portion 132 are annularly arranged, and the inner diameter of the limiting platform 141 is smaller than the outer diameter of the stepped portion 132 to ensure that the limiting platform 141 can effectively support and limit the stepped portion 132, thereby improving the limiting effect.

[0052] Furthermore, the needle 130 is integrally disposed within the oil outlet channel 150, and the stepped portion 132 has an oil leakage hole 133 for the flushing oil to flow through, so that the flushing oil can flow smoothly within the oil outlet channel 150, avoiding any impact on the flow of flushing oil caused by the engagement of the limiting platform 141 and the stepped portion 132. Specifically, there are multiple oil leakage holes 133, which are arranged in a circular array on the stepped portion 132. The multiple oil leakage holes 133 work together to allow flushing oil to pass through simultaneously, ensuring that the flow rate of the flushing oil flowing out of the oil outlet channel 150 meets the requirements.

[0053] Preferably, the outer tube 140 is provided with a constricted section 142 at the end away from the injection shell 110. The constricted section 142 is provided with a constricted inner wall 143 and a straight inner wall 144 in sequence. The flushing oil in the oil outlet channel 150 will pass through the constricted inner wall 143 and the straight inner wall 144 in sequence during the outflow process. The constricted inner wall 143 is used to gradually reduce the cross-sectional area of ​​the flushing oil so that the flushing oil can flow out stably and evenly from the straight inner wall 144.

[0054] Specifically, a capillary tube 134 is provided at the end of the needle 130 away from the injection housing 110, that is, the capillary tube 134 is located at the end of the body 131 away from the step portion 132. The capillary tube 134 is a straight tube, and part of the capillary tube 134 extends into the inner wall 144 of the straight cylinder and is coaxially spaced from the inner wall 144 of the straight cylinder. The capillary tube 134 is used to supply the original solution to flow out, and the inner wall 144 of the straight cylinder is used to supply the flushing oil to flow out, so that the original solution and the flushing oil form a coaxial sheath flow. When the force of the flushing oil is greater than the surface tension of the tiny droplets formed by the original solution, the tiny droplets fall off from the free end of the capillary tube 134 to form individual water-in-oil microdroplets.

[0055] Preferably, the microdroplet generating device 100 further includes a driving mechanism 160. The driving mechanism 160 is connected to the push rod 120 and is used to drive the push rod 120 to slide relative to the syringe 113 of the injection housing 110, so as to draw the original solution into the needle 130 or expel it from the needle 130. In this embodiment, the driving mechanism 160 uses a drive motor to drive the lead screw to rotate, and the lead screw and nut cooperate to drive the push rod 120 to move, but it is not limited to this. In other embodiments, the driving mechanism 160 can also be driven by a cylinder or a hydraulic cylinder. The driving method of the driving mechanism 160 is not specifically limited.

[0056] In this embodiment, both the injection housing 110 and the push rod 120 extend vertically. The needle 130 and the outer tube 140 are detachably connected to the bottom of the injection housing 110. The drive mechanism 160 is connected to the top of the push rod 120. The drive mechanism 160 can drive the push rod 120 to slide upward relative to the syringe 113 to achieve the liquid aspiration function. The drive mechanism 160 can also drive the push rod 120 to slide downward relative to the syringe 113 to achieve the liquid dispensing function.

[0057] Preferably, the microdroplet generating device 100 further includes an oil pump mechanism (not shown). The oil pump mechanism is connected to the oil inlet channel 112 via a second inlet 1143, and is used to introduce flushing oil into the oil inlet channel 112. The oil pump mechanism is also used to control the flow rate of the flushing oil entering the oil inlet channel 112 (i.e., flowing out from the oil outlet channel 150). Further, the oil pump mechanism is also connected to the push-pull channel 111 via a first inlet 1133, and is also used to introduce exhaust oil into the push-pull channel 111. The oil pump mechanism is also used to control the flow rate of the exhaust oil entering the push-pull channel 111.

[0058] The method of using the microdroplet generation device 100 includes the following steps:

[0059] Step S110: Slide the push rod 120 to the far limit position and introduce exhaust oil into the push-pull channel 111 to expel the air in the push-pull channel 111.

[0060] It should be noted that in step S110, the drive mechanism 160 first drives the push rod 120 to slide upward relative to the syringe 113 to the limit position. At this time, the push rod 120 is located at the far limit position. Then, the oil pump mechanism is used to introduce exhaust oil into the first inlet 1133 so that the exhaust oil fills the entire push-pull channel 111. During this process, the air in the push-pull channel 111 is completely squeezed out by the exhaust oil.

[0061] Step S120: Install the needle 130 onto the injection housing 110.

[0062] It should be noted that in step S120, the needle 130 is installed onto the injection housing 110 manually or by using a robotic arm, so that the needle 130 is engaged with the bottom of the syringe 113, thereby connecting the needle 130 with the push-pull channel 111.

[0063] Step S130: Slide the push rod 120 toward the needle 130 to expel air from the needle 130 through the venting oil.

[0064] It should be noted that in step S130, the drive mechanism 160 drives the push rod 120 to slide downward relative to the syringe 113, so as to push the exhaust oil in the push-pull channel 111 into the needle 130 until the exhaust oil fills the entire needle 130. During this process, the air in the needle 130 is completely squeezed out by the exhaust oil.

[0065] Step S140: Slide the push rod 120 away from the needle 130 to draw the original solution into the needle 130.

[0066] It should be noted that in step S140, the bottom end of the needle 130 is first inserted into the sample solution storage tube; then the drive mechanism 160 drives the push rod 120 to slide upward relative to the syringe 113 to draw the original solution in the sample solution storage tube into the needle 130. The amount drawn in is very small, about 20 μL. Therefore, after the aspiration is completed, the needle 130 contains both the original solution and the exhaust oil (the lower part is the original solution and the upper part is the exhaust oil), or only the original solution. The original solution will not enter the syringe 113.

[0067] Step S150: Install the outer tube 140 onto the injection housing 110.

[0068] It should be noted that in step S150, the outer tube 140 is installed onto the injection housing 110 manually or by using a robotic arm, so that the outer tube 140 is snapped into the bottom of the sleeve 114, thereby connecting the oil inlet channel 112 and the oil outlet channel 150.

[0069] Step S160: Flushing oil is introduced into the oil inlet channel 112 to expel air from the oil inlet channel 112 and the oil outlet channel 150.

[0070] It should be noted that in step S160, flushing oil is introduced into the second inlet 1143 by the oil pump mechanism so that the flushing oil fills the entire oil inlet channel 112 and oil outlet channel 150. During this process, the air in the oil inlet channel 112 and oil outlet channel 150 is completely squeezed out by the flushing oil.

[0071] Step S170: Slide the push rod 120 toward the needle 130 to push the original solution out of the needle 130, and at the same time output flushing oil through the oil outlet channel 150 to form water-in-oil microdroplets.

[0072] It should be noted that in step S170, the entire microdroplet generating device 100 is first moved above the reaction plate; then, the drive mechanism 160 drives the push rod 120 to slide downward relative to the syringe 113 to push the original solution in the needle 130 outward. During this process, the oil pump mechanism is used to introduce flushing oil into the second inlet 1143 so that the flushing oil flows out from the oil outlet channel 150. When the force of the flushing oil is greater than the surface tension of the microdroplets formed by the original solution, the microdroplets fall off from the end of the needle 130 to form individual water-in-oil microdroplets, thus completing the dripping operation.

[0073] Specifically, in step S170, the speed at which the push rod 120 slides downward driven by the drive mechanism 160 is proportional to the flow rate of the original solution. The flow rate of the original solution is controlled by controlling the downward sliding speed of the push rod 120. At the same time, the flow rate of the flushing oil is controlled by controlling the oil pump mechanism to ensure that the formed water-in-oil microdroplets meet the requirements for nucleic acid detection.

[0074] The microdroplet generating device 100 provided in this embodiment of the present invention has an injection housing 110 provided with a push-pull channel 111 and an oil inlet channel 112. The oil inlet channel 112 has an annular cross-section and surrounds the push-pull channel 111. The oil inlet channel 112 is coaxial with and separate from the push-pull channel 111. A push rod 120 is slidably disposed within the push-pull channel 111. The oil inlet channel 112 is used to supply flushing oil. The needle 130 and the outer tube 140 are both detachably connected to the injection housing 110. The needle 130 is connected to the push-pull channel 111. The device 100 is connected to the push rod 120. The needle 130 draws in the original solution when the push rod 120 slides away from the needle 130. An outer tube 140 is fitted over the needle 130, forming an oil outlet channel 150 between the outer tube 140 and the needle 130. The oil outlet channel 150 is connected to the oil inlet channel 112. The needle 130 also pushes out the original solution when the push rod 120 slides towards the needle 130. The oil outlet channel 150 outputs flushing oil while the original solution is being pushed out, thus forming water-in-oil microdroplets. Compared with existing technologies, the microdroplet generating device 100 provided by this invention, due to the coaxial and separately arranged oil inlet channel 112 and push-pull channel 111, and the outer tube 140 fitted over the needle 130 and forming the oil outlet channel 150 between them, can ensure that the proportion of the original solution in each water-in-oil microdroplet is the same, improving the uniformity of the water-in-oil microdroplets and ensuring the effectiveness of nucleic acid detection. This results in high detection efficiency, high detection accuracy, and good detection effect of the digital PCR detector.

[0075] Second Embodiment

[0076] Please refer to Figure 7 This utility model provides a microdroplet generating device 100. Compared with the first embodiment, the difference in this embodiment is that the shape of the end wall 1121 of the oil inlet channel 112 is different.

[0077] In this embodiment, the end wall 1121 is curved and gradually approaches the oil outlet channel 150 in the flow direction of the flushing oil entering from the second inlet 1143. Because the end wall 1121 has a clearance hole 1122 in the middle that fits tightly with the extension pipe 1132, the end wall 1121 has an annular curved surface. Specifically, during the process of flushing oil entering the oil inlet channel 112 through the second inlet 1143, the annular curved surface of the end wall 1121 can guide the flushing oil, preventing it from rushing directly to the opposite side wall. Instead, it flows downwards at a uniform speed along the curved surface, avoiding the formation of unstable fluid states (turbulence, vortices, etc.) in the oil inlet channel 112 due to the obstruction of the extension pipe 1132. This prevents the formation of bubbles and dead spaces, ensuring the uniformity and stability of the flushing oil flow.

[0078] In this embodiment, the end wall 1121 is curved (the curvature of the surface varies depending on the pressure and flow rate of the flushing oil), but it is not limited to this. In other embodiments, the end wall 1121 can also be inclined. In this case, the end wall 1121 is inclined to the horizontal plane. The end wall 1121 can also stably guide the flushing oil and ensure the uniformity and stability of the flushing oil flow. The shape of the end wall 1121 is not specifically limited.

[0079] The beneficial effects of the microdroplet generating device 100 provided in this embodiment are the same as those in the first embodiment, and will not be repeated here.

[0080] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A microdroplet generation device, characterized in that, The device includes an injection housing, a push rod, a needle, and an outer tube. The injection housing has a push-pull channel and an oil inlet channel. The oil inlet channel has an annular cross-section and surrounds the push-pull channel. The oil inlet channel is coaxial with and separated from the push-pull channel. The push rod is slidably disposed within the push-pull channel. The oil inlet channel is used to allow flushing oil to enter. The needle and the outer tube are detachably connected to the injection housing. The needle communicates with the push-pull channel and is used to draw in the original solution when the push rod slides away from the needle. The outer tube is sleeved over the needle, and an oil outlet channel is formed between the outer tube and the needle. The oil outlet channel communicates with the oil inlet channel. The needle is also used to expel the original solution when the push rod slides towards the needle. The oil outlet channel is used to output flushing oil while the original solution is expelled, forming water-in-oil microdroplets.

2. The microdroplet generation device according to claim 1, characterized in that, The injection housing includes a syringe and a cannula. The cannula is connected to the syringe and is sleeved outside the syringe. An oil inlet channel is formed between the cannula and the syringe. The push-pull channel is disposed inside the syringe. The needle is detachably connected to the syringe. The outer tube is detachably connected to the cannula.

3. The microdroplet generation device according to claim 2, characterized in that, The syringe includes a base and an extension tube connected to each other. The extension tube is disposed in the middle of the base, and the push-pull channel is disposed in both the base and the extension tube. The sleeve includes a connecting disc and a tube body connected to each other. The tube body is located in the middle of the connecting disc. Both the connecting disc and the tube body are sleeved outside the extension tube. The oil inlet channel is located between the tube body and the extension tube. The connecting disc is connected to the base.

4. The microdroplet generation device according to claim 3, characterized in that, The seat body has a first inlet, which is connected to the side wall of the push-pull channel. The first inlet is used for supplying and releasing exhaust oil. The connecting plate has a second inlet, which is connected to the side wall of the oil inlet channel. The second inlet is used to supply flushing oil.

5. The microdroplet generation device according to claim 4, characterized in that, The oil inlet channel has an end wall at the end away from the oil outlet channel. The end wall has a clearance hole, through which the extension tube passes. The end wall is curved or inclined, and it gradually approaches the oil outlet channel in the flow direction of the flushing oil introduced from the second inlet.

6. The microdroplet generation device according to claim 1, characterized in that, The outer tube is provided with a limiting platform, and the needle includes a body part and a step part that are connected to each other. The step part is located at one end of the body part near the injection shell, and the limiting platform abuts against the step part.

7. The microdroplet generation device according to claim 6, characterized in that, The stepped portion is provided with an oil leakage hole, which is used for the flow of flushing oil.

8. The microdroplet generation device according to claim 1, characterized in that, The outer tube has a constricted section at the end away from the injection housing. The constricted section has a constricted inner wall and a straight inner wall arranged in sequence. The needle has a capillary tube at the end away from the injection housing. The capillary tube extends into the straight inner wall and is coaxially spaced from the straight inner wall.

9. The microdroplet generation device according to claim 1, characterized in that, The microdroplet generating device further includes a driving mechanism connected to the push rod, which is used to drive the push rod to slide relative to the injection housing. And / or, the microdroplet generating device further includes an oil pump mechanism, which is connected to the oil inlet channel and is used to introduce flushing oil into the oil inlet channel.

10. A digital PCR detection instrument, characterized in that, Includes the microdroplet generation device as described in any one of claims 1-9.

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