Micro-droplet generation device, liquid dropping method thereof and digital PCR detector

Abstract

The invention discloses a micro-droplet generation device, a droplet dropping method thereof and a digital PCR 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 invention can ensure the same proportion of the original solution in each water-in-oil micro-droplet, improve the uniformity of the water-in-oil micro-droplet, and ensure the nucleic acid detection effect.

Description

Technical Field

[0001] The present invention relates to the technical field of nucleic acid detection, and in particular to a micro-droplet generating device and a droplet method thereof, and a digital PCR detector. Background Art

[0002] Droplet digital PCR is an absolute quantitative PCR technology that mainly uses a droplet method to disperse a solution containing the target nucleic acid into a large number of oil-in-water droplets to form tens of thousands of independent microreaction systems of equal volume. The initial number of target nucleic acid templates in each droplet is 0, 1 or more. In this way, after the PCR cycle, the droplet with one target nucleic acid will give a fluorescent signal, and the droplet without the target nucleic acid will not have a fluorescent signal. The target nucleic acid concentration of the original solution can be calculated based on the relative proportion of the two droplet numbers and the mathematical correction of the Poisson distribution.

[0003] At present, the preparation method of water-in-oil microdroplets is generally to mix the original solution and oil in a certain proportion, then perform spiral stirring, and then drip out at a certain flow rate to form water-in-oil microdroplets. However, this preparation method of spiral stirring can easily cause uneven mixing of the original solution and oil, resulting in different proportions of the original solution in each water-in-oil microdroplet, poor uniformity of the water-in-oil microdroplets, and directly affect the nucleic acid detection effect.

[0004] In view of this, it is particularly important to design a micro-droplet generating device with good uniformity and its droplet method, and a digital PCR detector, especially in nucleic acid detection. Summary of the invention

[0005] The purpose of the present invention is to provide a micro-droplet generating device, which can ensure that the proportion of the original solution in each oil-in-water micro-droplet is the same, improve the uniformity of the oil-in-water micro-droplet, and ensure the nucleic acid detection effect.

[0006] Another object of the present invention is to provide a droplet method for a micro-droplet generating device, which can ensure that the proportion of the original solution in each oil-in-water micro-droplet is the same, improve the uniformity of the oil-in-water micro-droplets, and ensure the nucleic acid detection effect.

[0007] Another object of the present invention is to provide a digital PCR detector, which can ensure that the proportion of the original solution in each oil-in-water microdroplet is the same, improve the uniformity of the oil-in-water microdroplet, and ensure the nucleic acid detection effect.

[0008] The present invention is achieved by adopting the following technical solutions.

[0009] A micro-droplet generating device comprises an injection shell, a push rod, a needle 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 and is arranged outside the push-pull channel. The oil inlet channel is coaxial with the push-pull channel and is arranged separately. The push rod is slidably arranged in the push-pull channel. The oil inlet channel is used for allowing flushing oil to pass through. The needle and the outer tube are both detachably connected to the injection shell. The needle is communicated with the push-pull channel. The needle is used to suck in an original solution when the push rod slides in a direction away from the needle. The outer tube is sleeved outside the needle. An oil outlet channel is formed between the outer tube and the needle. The oil outlet channel is communicated with the oil inlet channel. The needle is also used to press out the original solution when the push rod slides in a direction close to the needle. The oil outlet channel is used to output the flushing oil outward while the original solution is pressed out, so as to form oil-in-water micro-droplets.

[0010] Optionally, the injection shell includes a syringe and a sleeve, the sleeve is connected to the syringe and is sleeved outside the syringe, an oil inlet channel is formed between the sleeve and the syringe, the push-pull channel is arranged in the syringe, the needle is detachably connected to the syringe, and the outer tube is detachably connected to the sleeve.

[0011] Optionally, the syringe includes a seat body and an extension tube that are connected to each other, the extension tube is arranged in the middle of the seat body, and the push-pull channel is arranged in the seat body and the extension tube at the same time; the sleeve includes a connecting plate and a tube body that are connected to each other, the tube body is arranged in the middle of the connecting plate, the connecting plate and the tube body are both sleeved outside the extension tube, the oil inlet channel is arranged between the tube body and the extension tube, and the connecting plate is connected to the seat body.

[0012] Optionally, the seat body is provided with a first inlet, the first inlet is connected to the side wall of the push-pull channel, and the first inlet is used for the entry of exhaust oil; the connecting plate is provided with a second inlet, the second inlet is connected to the side wall of the oil inlet channel, and the second inlet is used for the entry of flushing oil.

[0013] Optionally, the oil inlet channel has an end wall at one end away from the oil outlet channel, the end wall is provided with a clearance hole, the extension tube is arranged through the clearance hole, the end wall is a curved surface or an inclined surface, and the end wall is gradually approached to the oil outlet channel in the flow direction of the flushing oil entering from the second inlet.

[0014] Optionally, a limiting platform is arranged inside the outer tube, and the needle comprises a main body portion and a step portion which are connected to each other, the step portion is arranged at one end of the main body portion close to the injection shell, and the limiting platform abuts against the step portion.

[0015] Optionally, the step portion is provided with an oil leakage hole for allowing flushing oil to flow through.

[0016] Optionally, a tapered section is provided at one end of the outer tube away from the injection shell, and a tapered inner wall and a straight barrel inner wall are provided in sequence in the tapered section. A capillary is provided at one end of the needle away from the injection shell, and the capillary part extends into the straight barrel inner wall and is coaxially spaced apart from the straight barrel inner wall.

[0017] Optionally, the micro-droplet generating device also includes a driving mechanism, which is connected to the push rod and is used to drive the push rod to slide relative to the injection housing; and / or, the micro-droplet generating device also 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.

[0018] A liquid dripping method for a micro-droplet generating device is applied to the above-mentioned micro-droplet generating device, and the liquid dripping method for the micro-droplet generating device comprises: installing a needle on an injection shell; sliding a push rod in a direction away from the needle to suck an original solution into the needle; installing an outer tube on the injection shell; sliding the push rod in a direction close to the needle to press the original solution out of the needle, and at the same time outputting flushing oil outward through an oil outlet channel to form oil-in-water micro-droplets.

[0019] Optionally, before the step of installing the needle on the injection shell, the dripping method of the micro-droplet generating device also includes: sliding the push rod to the far point limit position, and introducing exhaust oil into the push-pull channel to exhaust the air in the push-pull channel; after the step of installing the needle on the injection shell, the dripping method of the micro-droplet generating device also includes: sliding the push rod in a direction close to the needle to exhaust the air in the needle through the exhaust oil.

[0020] Optionally, before the step of sliding the push rod toward the needle to press the original solution out of the needle and outputting the flushing oil outward through the oil outlet channel to form oil-in-water micro-droplets, the dripping method of the micro-droplet generating device also includes: introducing flushing oil into the oil inlet channel to discharge the air in the oil inlet channel and the oil outlet channel through the flushing oil.

[0021] A digital PCR detector comprises the above-mentioned micro-droplet generating device, which comprises an injection shell, a push rod, a needle 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 and is arranged outside the push-pull channel. The oil inlet channel is coaxial with the push-pull channel and is separately arranged. The push rod is slidably arranged in the push-pull channel. The oil inlet channel is used for allowing flushing oil to pass through. The needle and the outer tube are both detachably connected to the injection shell. The needle is connected to the push-pull channel. The needle is used to suck in the original solution when the push rod slides in a direction away from the needle. The outer tube is sleeved outside the needle. 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 press out the original solution when the push rod slides in a direction close to the needle. The oil outlet channel is used to output the flushing oil to the outside while the original solution is pressed out, so as to form oil-in-water micro-droplets.

[0022] The micro-droplet generation device and the droplet method thereof, and the digital PCR detector provided by the present invention have the following beneficial effects:

[0023] The micro-droplet generating device provided by the present invention has an injection shell provided with a push-pull channel and an oil inlet channel. The cross section of the oil inlet channel is annular and is arranged outside the push-pull channel. The oil inlet channel is coaxial with the push-pull channel and is separately arranged. The push rod is slidably arranged in the push-pull channel. The oil inlet channel is used for allowing flushing oil to pass through. The needle and the outer tube are both detachably connected to the injection shell. The needle is communicated with the push-pull channel. The needle is used to suck in the original solution when the push rod slides in a direction away from the needle. The outer tube is sleeved outside the needle, and an oil outlet channel is formed between the outer tube and the needle. The oil outlet channel is communicated with the oil inlet channel. The needle is also used to press out the original solution when the push rod slides in a direction close to the needle. The oil outlet channel is used to output the flushing oil to the outside while the original solution is pressed out, so as to form oil-in-water micro-droplets. Compared with the prior art, the micro-droplet generating device provided by the present invention adopts coaxial and separately arranged oil inlet channel and push-pull channel and an outer tube which is sleeved outside the needle and forms an oil outlet channel between the needle. Therefore, it can ensure that the proportion of the original solution in each oil-in-water micro-droplet is the same, thereby improving the uniformity of the oil-in-water micro-droplets and ensuring the nucleic acid detection effect.

[0024] The liquid dripping method of the micro-droplet generating device provided by the present invention is applied to the micro-droplet generating device, which can ensure that the proportion of the original solution in each oil-in-water micro-droplet is the same, improve the uniformity of the oil-in-water micro-droplet, and ensure the nucleic acid detection effect.

[0025] The digital PCR detector provided by the present invention includes a micro-droplet generating device, which can ensure that the proportion of the original solution in each oil-in-water micro-droplet is the same, improve the uniformity of the oil-in-water micro-droplet, and ensure the nucleic acid detection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A schematic structural diagram of a micro-droplet generating device provided in the first embodiment of the present invention;

[0028] Figure 2 A cross-sectional view showing that the injection housing is connected to the needle and the outer tube simultaneously in the micro-droplet generating device provided by the first embodiment of the present invention;

[0029] Figure 3 A cross-sectional view showing that the injection housing is connected to the needle and the outer tube simultaneously in the micro-droplet generating device provided by the first embodiment of the present invention;

[0030] Figure 4A cross-sectional view of the sliding cooperation between the injection housing and the push rod in the micro-droplet generating device provided by the first embodiment of the present invention;

[0031] Figure 5 A cross-sectional view of the micro-droplet generating device provided in the first embodiment of the present invention, in which the outer tube is sleeved outside the needle;

[0032] Figure 6 A cross-sectional view of the outer tube sleeve disposed outside the needle in the micro-droplet generating device provided in the first embodiment of the present invention;

[0033] Figure 7 A partial cross-sectional view of an injection housing in a micro-droplet generating device provided in a second embodiment of the present invention.

[0034] Icons: 100-micro-droplet generating device; 110-injection shell; 111-push-pull channel; 112-oil inlet channel; 1121-end wall; 1122-give way hole; 113-syringe; 1131-seat body; 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 head; 131-main body; 132-step part; 133-oil leakage hole; 134-capillary; 140-outer tube; 141-limiting platform; 142-narrowing section; 143-narrowing inner wall; 144-straight tube inner wall; 150-oil outlet channel; 160-driving mechanism. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0036] 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 invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0038] In the description of the present invention, it should be noted that the terms "inside", "outside", "upper", "lower", "horizontal", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the product of the invention is usually placed when in use, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0039] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "connect", "install", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments can be combined with each other.

[0041] First embodiment

[0042] Please refer to Figures 1 to 6 The embodiment of the present invention provides a digital PCR detector (not shown) for nucleic acid detection. It can ensure that the proportion of the original solution in each oil-in-water microdroplet is the same, improve the uniformity of the oil-in-water microdroplet, and ensure the nucleic acid detection effect.

[0043] The digital PCR detector includes a micro-droplet generating device 100, a temperature control device (not shown) and a microscopic photographing device (not shown). The micro-droplet generating device 100 is used to make a large number of oil-in-water micro-droplets from the original solution in a sample, and inject these oil-in-water micro-droplets into a reaction plate placed on the temperature control device; the temperature control device is used to perform a temperature rise and fall cycle on these oil-in-water micro-droplets through the reaction plate, and each time the temperature rise and fall cycle is performed, the number of target nucleic acids in each oil-in-water micro-droplet doubles, and this is repeated to greatly increase the number of trace target nucleic acids; the microscopic photographing device is used to photograph and measure all oil-in-water micro-droplets after the temperature rise and fall cycle is completed. The oil-in-water micro-droplets with the target nucleic acid initially will give a fluorescent signal, and the oil-in-water micro-droplets without the target nucleic acid will not have a fluorescent signal. According to the relative proportion of the two oil-in-water micro-droplets and the mathematical correction of the Poisson distribution, the target nucleic acid concentration of the original solution in the corresponding sample can be inferred.

[0044] The micro-droplet 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 cross section of the oil inlet channel 112 is annular and is arranged outside the push-pull channel 111. The oil inlet channel 112 is coaxial with the push-pull channel 111 and is separated so that the oil inlet channel 112 and the push-pull channel 111 are independent of each other and do not affect each other, wherein the oil inlet channel 112 is used for flushing oil to pass. Specifically, the push rod 120 is slidably arranged in the push-pull channel 111, and the push rod 120 can slide relative to the push-pull channel 111 to form a negative pressure or a positive pressure in the push-pull channel 111, thereby realizing the liquid suction function and the liquid dripping function, and the push-pull channel 111 can guide and limit the push rod 120. 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 needle 130 is used to suck the original solution when the push rod 120 slides in a direction away from the needle 130. The outer tube 140 is sleeved outside the needle 130. An oil outlet channel 150 is formed between the outer tube 140 and the needle 130. The oil outlet channel 150 is connected to the oil inlet channel 112. 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 press out the original solution when the push rod 120 slides in a direction close to the needle 130. The oil outlet channel 150 is used to output the flushing oil to the outside while the original solution is pressed out to form oil-in-water micro droplets. In this way, through the limiting effect of the needle 130 and the outer tube 140, and the reasonable control of the flow rate of the original solution and the flushing oil, the original solution and the flushing oil can be made to flow out stably from the micro-droplet 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), and form oil-in-water micro-droplets, thereby ensuring that the proportion of the original solution in each oil-in-water micro-droplet is the same, improving the uniformity of the oil-in-water micro-droplets, and ensuring the nucleic acid detection effect.

[0045] Furthermore, during the use of the micro-droplet generating device 100, the air in the push-pull channel 111 and the needle 130 is first removed; then a certain amount of original solution is sucked through the needle 130; then the original solution flows out from the needle 130 under the pressure of the push rod 120 to form tiny droplets. 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 tiny droplets 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 tiny droplets, the tiny droplets fall off from the end of the needle 130 and flow into the reaction plate below with the flushing oil, thereby forming original solution droplets (i.e., oil-in-water droplets) wrapped by the flushing oil. Specifically, as long as the flow rates of the original solution and the flushing oil are uniform (the flow rates of the two liquids are different), uniform oil-in-water microdroplets can be formed. The size of the oil-in-water microdroplets is affected by the flow rates and physical properties (viscosity and density, etc.) of the two liquids. If oil-in-water microdroplets of different sizes are to be generated, the flow rates and composition ratios of the two liquids need to be adjusted.

[0046] It should be noted that the needle 130 and the outer tube 140 are both consumables. During the dripping process, the needle 130 needs to be installed on the injection housing 110 first, 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 suck the original solution in the sample solution storage tube into the needle 130 (the amount of suction is very small, about 20 μL, so the original solution will not enter the injection housing 110); then the outer tube 140 is installed on the injection housing 110, so that the outer tube 140 is spaced outside the needle 130, and an oil outlet channel 150 is formed between the outer tube 140 and the needle 130; then the original solution is dripped outward, 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 wraps around the original solution droplets to form oil-in-water droplets. In this way, during each dripping process, only the needle 130 and the outer tube 140 are in contact with the original solution of the sample. To avoid cross-contamination of multiple samples, after each dripping is completed, the used needle 130 and the outer tube 140 need to be removed and replaced with a new needle 130 and the outer tube 140 to facilitate the next dripping.

[0047] The injection housing 110 includes a syringe 113 and a sleeve 114. The sleeve 114 is connected to the syringe 113 and sleeved outside the syringe 113. An annular oil inlet channel 112 is formed between the sleeve 114 and the syringe 113. The push-pull channel 111 is arranged in the syringe 113 so that the oil inlet channel 112 is surrounded outside the push-pull channel 111. Specifically, the needle 130 is detachably connected to the syringe 113 so that the needle 130 is connected to the push-pull channel 111; the outer tube 140 is detachably connected to the sleeve 114 so that the oil outlet channel 150 is connected to the oil inlet channel 112; in this way, the needle 130 and the outer tube 140 can be independently disassembled and assembled, which is convenient and practical.

[0048] The syringe 113 includes a seat body 1131 and an extension tube 1132 connected to each other. In this embodiment, the seat body 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 seat body 1131, and the push-pull channel 111 is disposed in the seat body 1131 and the extension tube 1132 at the same time. The push rod 120 extends into the push-pull channel 111 from one end of the seat body 1131 away from the extension tube 1132, and can slide in the push-pull channel 111, so that negative pressure or positive pressure is formed in the push-pull channel 111.

[0049] The sleeve 114 includes a connecting disc 1141 and a tube body 1142 which are 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 arranged in the middle of the connecting disc 1141, and the connecting disc 1141 and the tube body 1142 are both sleeved outside the extension tube 1132, that is, the extension tube 1132 is arranged through the connecting disc 1141 and the tube body 1142 in sequence. Specifically, the connecting disc 1141 is sealedly connected to the extension tube 1132, that is, there is no gap between the connecting disc 1141 and the extension tube 1132, and the oil inlet channel 112 is arranged between the tube body 1142 and the extension tube 1132 to prevent the flushing oil from flowing in a direction away from the oil outlet channel 150. The connecting disc 1141 is connected to the seat body 1131 to fix the relative position of the syringe 113 and the sleeve 114 to prevent the sleeve 114 from rotating or displacing relative to the syringe 113.

[0050] Preferably, the seat body 1131 is provided with a first inlet 1133, which is connected to the side wall of the push-pull channel 111. The first inlet 1133 is used for the entry of exhaust oil. The exhaust oil is used to enter the push-pull channel 111 and the needle 130 before formal dripping to exclude the air in the push-pull channel 111 and the needle 130 to ensure the dripping effect.

[0051] Preferably, the connecting disk 1141 is provided with a second inlet 1143, which is connected to the side wall of the oil inlet channel 112. The second inlet 1143 is used for the entry of flushing oil, and the flushing oil is used to flush the tiny droplets at the end of the needle 130 to form original solution droplets (i.e., oil-in-water droplets) wrapped by the flushing oil.

[0052] It should be noted that the composition and proportion of exhaust oil and flushing oil are exactly the same. The names are distinguished only for the sake of ease of understanding. In essence, they are both a combination of mineral oil and some chemical solvents.

[0053] Furthermore, the end of the oil inlet channel 112 away from the oil outlet channel 150 has an end wall 1121, the end wall 1121 is provided with a clearance hole 1122, the extension tube 1132 is arranged through the clearance hole 1122, the extension tube 1132 and the clearance hole 1122 are closely matched, and there is no gap between the extension tube 1132 and the inner wall of the clearance hole 1122 to prevent the flushing oil from flowing in the direction away from the oil outlet channel 150. In this embodiment, the end wall 1121 is arranged in a horizontal plane, and the second inlet 1143 is arranged close to the end wall 1121. The flushing oil entering the oil inlet channel 112 through the second inlet 1143 can stably flow in the direction close to the oil outlet channel 150 under the stopping effect of the end wall 1121.

[0054] In this embodiment, an assembly section 1134 is provided at one end of the extension tube 1132 away from the seat body 1131, and the assembly section 1134 protrudes from the tube body 1142. The needle 130 is sleeved outside the assembly section 1134 and is clamped with the assembly section 1134 to achieve a detachable connection between the needle 130 and the extension tube 1132, which is easy to disassemble and assemble, and can ensure the sealing of the connection between the needle 130 and the push-pull channel 111.

[0055] In this embodiment, a mating section 1144 is provided at one end of the tube body 1142 away from the connecting plate 1141, and the outer tube 140 is sleeved outside the mating section 1144 and clamped with the mating section 1144 to achieve a detachable connection between the outer tube 140 and the tube 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.

[0056] Preferably, a limiting platform 141 is provided inside the outer tube 140, and the needle 130 includes a main body 131 and a step portion 132 connected to each other. The step portion 132 is provided at one end of the main body 131 close to the injection housing 110, and the limiting platform 141 abuts against the step portion 132. The limiting platform 141 can limit the step portion 132 to limit the entire needle 130, prevent the needle 130 from being separated from the extension tube 1132, and ensure the stability of the clamping of the needle 130 and the extension tube 1132. Specifically, the limiting platform 141 and the step portion 132 are both arranged in an annular shape, and the inner diameter of the limiting platform 141 is smaller than the outer diameter of the step portion 132, so as to ensure that the limiting platform 141 can effectively support and limit the step portion 132, thereby improving the limiting effect.

[0057] Furthermore, the needle 130 is disposed in its entirety in the oil outlet channel 150, and the step portion 132 is provided with an oil leakage hole 133, which is used to allow flushing oil to flow through, so that the flushing oil can flow smoothly in the oil outlet channel 150, and avoid the influence of the cooperation between the limit platform 141 and the step portion 132 on the flow of the flushing oil. Specifically, there are a plurality of oil leakage holes 133, which are disposed in a circular array on the step portion 132, and the plurality of oil leakage holes 133 work together to allow flushing oil to pass through at the same time, so as to ensure that the flow rate of the flushing oil flowing out of the oil outlet channel 150 can meet the requirements.

[0058] Preferably, a tapered section 142 is provided at the end of the outer tube 140 away from the injection shell 110, and a tapered inner wall 143 and a straight inner wall 144 are sequentially provided in the tapered section 142. The flushing oil in the oil outlet channel 150 will pass through the tapered inner wall 143 and the straight inner wall 144 in sequence during the outflow process, wherein the tapered inner wall 143 is used to gradually limit the cross-sectional area of ​​the flushing oil so that the flushing oil can flow out from the straight inner wall 144 stably and evenly.

[0059] Specifically, a capillary 134 is provided at one end of the needle 130 away from the injection housing 110, that is, the capillary 134 is provided at one end of the main body 131 away from the step portion 132. The capillary 134 is a straight tube, and a portion of the capillary 134 extends into the inner wall 144 of the straight tube, and is coaxially spaced with the inner wall 144 of the straight tube. The capillary 134 is used for the original solution to flow out, and the inner wall 144 of the straight tube is used for the flushing oil to flow out, so that the original solution and the flushing oil have 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 134 to form oil-in-water micro droplets.

[0060] Preferably, the micro-droplet generating device 100 further includes a driving mechanism 160. The driving mechanism 160 is connected to the push rod 120, and the driving mechanism 160 is used to drive the push rod 120 to slide relative to the syringe 113 of the injection housing 110, so as to suck the original solution into the needle 130 or press it out from the needle 130. In this embodiment, the driving mechanism 160 drives the push rod 120 to move by driving the screw rod to rotate by a driving motor, and the screw rod cooperates with the nut, 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, and the driving method of the driving mechanism 160 is not specifically limited.

[0061] In this embodiment, the injection housing 110 and the push rod 120 are both extended in the vertical direction, the needle 130 and the outer tube 140 are both detachably connected to the bottom of the injection housing 110, and the driving mechanism 160 is connected to the top of the push rod 120. The driving mechanism 160 can drive the push rod 120 to slide upward relative to the syringe 113 to achieve the liquid suction function. The driving mechanism 160 can also drive the push rod 120 to slide downward relative to the syringe 113 to achieve the liquid discharge function.

[0062] Preferably, the micro-droplet generating device 100 further includes an oil pump mechanism (not shown). The oil pump mechanism is connected to the oil inlet channel 112 through the second inlet 1143, and the oil pump mechanism is used to introduce flushing oil into the oil inlet channel 112, and the oil pump mechanism is used to control the flow rate of the flushing oil introduced into 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 through the first inlet 1133, and the oil pump mechanism is also used to introduce exhaust oil into the push-pull channel 111, and the oil pump mechanism is used to control the flow rate of the exhaust oil introduced into the push-pull channel 111.

[0063] The embodiment of the present invention further provides a liquid dripping method of a micro-droplet generating device, which is applied to the above-mentioned micro-droplet generating device 100. The liquid dripping method of the micro-droplet generating device comprises the following steps:

[0064] Step S110 : Slide the push rod 120 to the far-point limit position, and introduce exhaust oil into the push-pull channel 111 to exhaust the air in the push-pull channel 111 .

[0065] It should be noted that in step S110, the driving mechanism 160 is first used to drive the push rod 120 to slide upward to the extreme position relative to the syringe 113, at which time the push rod 120 is located at the far point extreme 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.

[0066] Step S120 : installing the needle 130 onto the injection housing 110 .

[0067] It should be noted that in step S120 , the needle 130 is installed on 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 to the push-pull channel 111 .

[0068] Step S130: Slide the push rod 120 toward the needle 130 to discharge the air in the needle 130 through the exhaust oil.

[0069] It should be noted that in step S130, the driving mechanism 160 is used to drive the push rod 120 to slide downward relative to the syringe 113 to press 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.

[0070] Step S140 : Slide the push rod 120 in a direction away from the needle 130 to draw the original solution into the needle 130 .

[0071] 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 driving mechanism 160 is used to drive the push rod 120 to slide upward relative to the syringe 113 to suck the original solution in the sample solution storage tube into the needle 130, wherein the suction volume is very small, about 20 μL, so after the suction is completed, there are both original solution and exhaust oil in the needle 130 (the lower part is the original solution, and the upper part is the exhaust oil), or there is only the original solution, and the original solution will not enter the syringe 113.

[0072] Step S150 : installing the outer tube 140 onto the injection housing 110 .

[0073] It should be noted that in step S150 , the outer tube 140 is installed on the injection housing 110 manually or by a robotic arm so that the outer tube 140 is snapped onto the bottom of the sleeve 114 , thereby connecting the oil inlet channel 112 with the oil outlet channel 150 .

[0074] Step S160: Flushing oil is introduced into the oil inlet channel 112 to discharge the air in the oil inlet channel 112 and the oil outlet channel 150 through the flushing oil.

[0075] It should be noted that in step S160, flushing oil is introduced into the second inlet 1143 by using the oil pump mechanism so that the flushing oil fills the entire oil inlet channel 112 and the oil outlet channel 150. During this process, the air in the oil inlet channel 112 and the oil outlet channel 150 is completely squeezed out by the flushing oil.

[0076] Step S170: Slide the push rod 120 toward the needle 130 to press the original solution out of the needle 130, and output the flushing oil to the outside through the oil outlet channel 150 to form water-in-oil micro droplets.

[0077] It should be noted that in step S170, the entire micro-droplet generating device 100 is first moved to the top of the reaction disk; then the driving mechanism 160 is used to drive the push rod 120 to slide downward relative to the syringe 113 to press 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 tiny droplets formed by the original solution, the tiny droplets fall off from the end of the needle 130 to form oil-in-water micro-droplets, thereby completing the dripping operation.

[0078] Specifically, in step S170, the speed at which the driving mechanism 160 drives the push rod 120 to slide downward is proportional to the flow rate of the original solution. The flow rate of the original solution is controlled by controlling the speed at which the push rod 120 slides downward. At the same time, the flow rate of the flushing oil is controlled by controlling the oil pump mechanism to ensure that the formed oil-in-water droplets meet the requirements of nucleic acid detection.

[0079] In the micro-droplet generating device 100 provided by the embodiment of the present invention, the injection housing 110 is provided with a push-pull channel 111 and an oil inlet channel 112. The cross section of the oil inlet channel 112 is annular and is arranged outside the push-pull channel 111. The oil inlet channel 112 is coaxial with the push-pull channel 111 and is separated. The push rod 120 is slidably arranged in the push-pull channel 111. The oil inlet channel 112 is used for supplying flushing oil. The needle 130 and the outer tube 140 are both detachably connected to the injection housing 110. The needle 130 and the push-pull channel 111 is connected, the needle 130 is used to suck the original solution when the push rod 120 slides in the direction away from the needle 130, the outer tube 140 is sleeved outside the needle 130, and an oil outlet channel 150 is formed between the outer tube 140 and the needle 130, and the oil outlet channel 150 is connected with the oil inlet channel 112, and the needle 130 is also used to press out the original solution when the push rod 120 slides in the direction close to the needle 130, and the oil outlet channel 150 is used to output the flushing oil outward while the original solution is pressed out to form oil-in-water micro-droplets. Compared with the prior art, the micro-droplet generation device 100 provided by the present invention adopts the coaxial and separated oil inlet channel 112 and the push-pull channel 111 and the outer tube 140 sleeved outside the needle 130 and forming the oil outlet channel 150 between the needle 130, so it can ensure that the proportion of the original solution in each oil-in-water micro-droplet is the same, improve the uniformity of the oil-in-water micro-droplet, and ensure the nucleic acid detection effect. The liquid dropping method of the micro-droplet generating device is simple in steps and the liquid dropping is uniform; and the digital PCR detector is high in detection efficiency, high in detection accuracy and good in detection effect.

[0080] Second embodiment

[0081] Please refer to Figure 7 The embodiment of the present invention provides a micro-droplet generating device 100. Compared with the first embodiment, the difference of this embodiment is that the shape of the end wall 1121 of the oil inlet channel 112 is different.

[0082] In this embodiment, the end wall 1121 is arranged in a curved surface, and the end wall 1121 is arranged gradually close to the oil outlet channel 150 in the flow direction of the flushing oil introduced from the second inlet 1143. Since a clearance hole 1122 that is closely matched with the extension tube 1132 is provided in the middle of the end wall 1121, the end wall 1121 is in the shape of an annular curved surface. Specifically, in the process of the 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 to prevent it from rushing directly to the opposite side wall, but to flow downward at a uniform speed along the curved surface, thereby avoiding the formation of an unstable fluid state (turbulence, vortex, etc.) in the oil inlet channel 112 due to the obstruction of the extension tube 1132, thereby preventing the formation of bubbles and dead space, and ensuring the uniformity and stability of the flushing oil flow.

[0083] In the present embodiment, the end wall 1121 is provided as a curved surface (the curvature of the curved surface is different due to different pressures and flow rates of the flushing oil), but it is not limited to this. In other embodiments, the end wall 1121 may also be provided as an inclined surface. In this case, the end wall 1121 is inclined to the horizontal plane. The end wall 1121 can also stably drain the flushing oil to ensure the uniformity and stability of the flushing oil flow. The shape of the end wall 1121 is not specifically limited.

[0084] The beneficial effects of the micro-droplet generating device 100 provided in the embodiment of the present invention are the same as those of the first embodiment, and will not be described in detail herein.

[0085] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A micro-droplet generating device, characterized in that: The invention comprises an injection shell, a push rod, a needle and an outer tube, wherein 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 and is arranged outside the push-pull channel, the oil inlet channel is coaxial with the push-pull channel and is arranged separately, the push rod is slidably arranged in the push-pull channel, the oil inlet channel is used for allowing flushing oil to pass through, the needle and the outer tube are both detachably connected to the injection shell, the needle is communicated with the push-pull channel, the needle is used for sucking in the original solution when the push rod slides in a direction away from the needle, the outer tube is sleeved outside the needle, an oil outlet channel is formed between the outer tube and the needle, the oil outlet channel is communicated with the oil inlet channel, the needle is also used for pressing out the original solution when the push rod slides in a direction close to the needle, and the oil outlet channel is used for outputting the flushing oil outward while the original solution is pressed out to form oil-in-water micro-droplets.

2. The micro-droplet generating device according to claim 1, characterized in that: The injection housing includes a syringe and a sleeve, the sleeve is connected to the syringe and is sleeved outside the syringe, the oil inlet channel is formed between the sleeve and the syringe, the push-pull channel is arranged in the syringe, the needle is detachably connected to the syringe, and the outer tube is detachably connected to the sleeve.

3. The micro-droplet generating device according to claim 2, characterized in that: The syringe comprises a seat body and an extension tube connected to each other, the extension tube is arranged in the middle of the seat body, and the push-pull channel is arranged in both the seat body and the extension tube; The sleeve includes a connecting plate and a tube body connected to each other, the tube body is arranged in the middle of the connecting plate, the connecting plate and the tube body are both sleeved outside the extension tube, the oil inlet channel is arranged between the tube body and the extension tube, and the connecting plate is connected to the seat body.

4. The micro-droplet generating device according to claim 3, characterized in that: The seat body is provided with a first inlet, the first inlet is communicated with the side wall of the push-pull channel, and the first inlet is used for exhaust oil to enter; The connecting plate is provided with a second inlet, the second inlet is communicated with the side wall of the oil inlet channel, and the second inlet is used for flushing oil to pass through.

5. The micro-droplet generating device according to claim 4, characterized in that: The oil inlet channel has an end wall at one end away from the oil outlet channel, the end wall is provided with a clearance hole, the extension tube is arranged through the clearance hole, the end wall is a curved surface or an inclined surface, and the end wall is arranged gradually close to the oil outlet channel in the flow direction of the flushing oil introduced from the second inlet.

6. The micro-droplet generating device according to claim 1, characterized in that: A limiting platform is arranged inside the outer tube, and the needle head comprises a main body portion and a step portion which are connected to each other. The step portion is arranged at one end of the main body portion close to the injection housing, and the limiting platform abuts against the step portion.

7. The micro-droplet generating device according to claim 6, characterized in that: The step portion is provided with an oil leakage hole, and the oil leakage hole is used for flushing oil to flow through.

8. The micro-droplet generating device according to claim 1, characterized in that: A constricted section is arranged at one end of the outer tube away from the injection shell, and a constricted inner wall and a straight inner wall are arranged in sequence in the constricted section; a capillary is arranged at one end of the needle away from the injection shell, and the capillary part extends into the straight inner wall and is coaxially spaced from the straight inner wall.

9. The micro-droplet generating device according to claim 1, characterized in that: The micro-droplet generating device further comprises a driving mechanism, the driving mechanism is connected to the push rod, and the driving mechanism is used to drive the push rod to slide relative to the injection housing; And / or, the micro-droplet generating device further comprises an oil pump mechanism, the oil pump mechanism is communicated with the oil inlet channel, and the oil pump mechanism is used to introduce flushing oil into the oil inlet channel.

10. A droplet method for a micro-droplet generating device, characterized in that: Applied to the micro-droplet generating device according to any one of claims 1 to 9, the droplet method of the micro-droplet generating device comprises: Installing the needle onto the injection housing; Sliding the push rod in a direction away from the needle to draw the original solution into the needle; installing the outer tube onto the injection housing; The push rod is slid toward the direction close to the needle to press the original solution out of the needle, and at the same time, the flushing oil is output outward through the oil outlet channel to form water-in-oil micro droplets.

11. The liquid dropping method of the micro-droplet generating device according to claim 10, characterized in that: Before the step of installing the needle onto the injection housing, the droplet method of the micro-droplet generating device further includes: sliding the push rod to a far-point limit position, and introducing exhaust oil into the push-pull channel to exhaust the air in the push-pull channel; After the step of installing the needle onto the injection housing, the dripping method of the micro-droplet generating device further includes: sliding the push rod toward the direction close to the needle to exhaust the air in the needle through exhaust oil.

12. The droplet method of the micro-droplet generating device according to claim 10, characterized in that: Before the step of sliding the push rod toward the needle to press the original solution out of the needle and outputting the flushing oil through the oil outlet channel to form water-in-oil micro-droplets, the droplet method of the micro-droplet generating device further includes: Flushing oil is introduced into the oil inlet passage to discharge the air in the oil inlet passage and the oil outlet passage through the flushing oil.

13. A digital PCR detector, characterized in that: It comprises the micro-droplet generating device as described in any one of claims 1 to 9.

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