CN212396772U

CN212396772U - Micro-droplet preparation system and micro-fluidic chip

Info

Publication number: CN212396772U
Application number: CN202021968462.XU
Authority: CN
Inventors: 王帅超; 梁帅; 曾杰生; 王哲
Original assignee: Guangdong Shunde Industrial Design Institute
Current assignee: Guangdong Shunde Industrial Design Institute
Priority date: 2020-09-10
Filing date: 2020-09-10
Publication date: 2021-01-26
Anticipated expiration: 2030-09-10

Abstract

The utility model relates to a droplet preparation system and micro-fluidic chip, micro-fluidic chip includes the chip board. The chip board is provided with a continuous phase hole, a discrete phase hole, a micro-droplet liquid outlet hole, a first flow channel and a second flow channel. The continuous phase hole is communicated with the middle part of the second flow passage through the first flow passage. The discrete phase hole is communicated with the droplet liquid outlet hole through a second flow passage. The first flow channel is provided with a first roundabout channel section, and the second flow channel is provided with a second roundabout channel section from one end connected with the discrete phase hole to the middle part of the second flow channel. On one hand, the first roundabout channel section is beneficial to fully and uniformly mixing the continuous phase fluid and playing a role in stabilizing the flow, and the second roundabout channel section is also beneficial to fully and uniformly mixing the discrete phase fluid and playing a role in stabilizing the flow; on the other hand, the shear stress of the two phases can be controlled by realizing control, and droplets with uniform size can be stably generated at the intersection under the action of the shear stress of the continuous phase fluid after the dispersed phase fluid enters the micro-channel.

Description

Micro-droplet preparation system and micro-fluidic chip

Technical Field

The utility model relates to a droplet preparation technical field especially relates to droplet preparation system and micro-fluidic chip.

Background

Traditionally, droplet microfluidics is a technology of injecting immiscible liquid into a microfluidic chip to generate uniform droplets meeting various size requirements at an extremely high speed, and a technology of integrating basic operation units such as sample preparation, reaction, separation, detection and the like in analysis processes such as biology, chemistry, medicine and the like on a micron-scale chip to automatically complete the whole analysis process. Macroscopic samples can perform a variety of chemical-physical reactions in tens of thousands of microfluidic chips (individual droplet volumes on the nano-to picoliter scale). By measuring and analyzing these droplets, the accuracy and sensitivity of the sample detection analysis can be greatly improved. However, the conventional microfluidic chip has poor stability in generating droplets.

SUMMERY OF THE UTILITY MODEL

Accordingly, there is a need to overcome the drawbacks of the prior art and to provide a droplet preparation system and a microfluidic chip, which can improve the stability of droplet generation and facilitate the generation of droplets with uniform size.

The technical scheme is as follows: a microfluidic chip, comprising: the chip board is provided with a continuous phase hole, a discrete phase hole, a droplet liquid outlet hole, a first flow channel and a second flow channel, the continuous phase hole is communicated with the middle part of the second flow channel through the first flow channel, the discrete phase hole is communicated with the droplet liquid outlet hole through the second flow channel, the first flow channel is provided with a first roundabout channel section, and a second roundabout channel section is arranged from one end, connected with the discrete phase hole, of the second flow channel to the middle part of the second flow channel.

On one hand, the microfluidic chip has the advantages that the first flow channel is provided with the first roundabout channel section, the first roundabout channel section is beneficial to fully and uniformly mixing continuous phase fluid and playing a role in stabilizing flow, and the second roundabout channel section is also beneficial to fully and uniformly mixing discrete phase fluid and playing a role in stabilizing flow; on the other hand, the length of the path from the continuous phase hole to the intersection of the first flow channel and the second flow channel can be adjusted when the shape of the first circuitous channel section is changed and the length of the path from the discrete phase hole to the intersection can be adjusted when the shape of the second circuitous channel section is changed under the condition that the volume size of the chip board is not increased, the shear stress when two phases are contacted can be controlled by controlling the length of the path from the continuous phase hole to the intersection and the length of the path from the discrete phase hole to the intersection, and after the dispersed phase fluid enters the micro-flow channel, droplets with uniform size (such as water-in-oil (W/O) droplets can be stably generated at the intersection under the shear stress of the continuous phase fluid, and the oil-water ratio is close to 1: 1).

In one embodiment, the first detour channel segment is a S-shaped, C-shaped, Z-shaped or L-shaped detour channel, and the second detour channel segment is an S-shaped, C-shaped, Z-shaped or L-shaped detour channel.

In one embodiment, the microfluidic chip further includes a bottom cover plate, the continuous phase hole, the discrete phase hole, the droplet liquid outlet hole, the first flow channel and the second flow channel are all formed by one side surface of the chip board penetrating through to the other side surface of the chip board, and the bottom cover plate is stacked under the chip board to close the bottom surface of the chip board.

In one embodiment, the bottom cover plate and the chip plate are connected in a bonding mode, an adhesive connection, a welding connection, a screw connection, a riveting connection, a pin connection or a clamping connection.

In one embodiment, the chip board is further provided with a first sample inlet tube communicated with the continuous phase hole, a second sample inlet tube communicated with the discrete phase hole, and a sample outlet tube communicated with the droplet liquid outlet hole; the first sample inlet pipe, the second sample inlet pipe and the sample outlet pipe are arranged on the chip board and deviate from the side face of the bottom cover plate.

In one embodiment, the bottom cover plate and the chip plate are both transparent plates.

In one embodiment, an end of the second flow channel connected to the droplet outlet hole includes a gradual channel section, and an aperture of the gradual channel section gradually increases in a direction close to the droplet outlet hole.

In one embodiment, the microfluidic chip further comprises a first filtering structure and a second filtering structure, the first filtering structure is disposed at the sample inlet end of the first flow channel, and the second filtering structure is disposed at the sample inlet end of the second flow channel.

In one embodiment, the continuous phase hole, the discrete phase hole, the droplet outlet hole, the first flow channel and the second flow channel are more than two; the more than two continuous phase holes and the more than two first flow channels are respectively arranged corresponding to the more than two microdroplet liquid outlet holes one by one; more than two discrete phase holes and more than two second flow channels are respectively arranged corresponding to more than two microdroplet liquid outlet holes one to one.

A microdroplet preparation system comprises the microfluidic chip, a gas pressure controller and a gas source power device, wherein the gas source power device is used for respectively introducing gas into the continuous phase hole and the discrete phase hole, and the gas pressure controller is used for controlling the gas pressure introduced into the continuous phase hole and the discrete phase hole.

When the micro-droplet preparation system works, a trace quantitative pipette is used for respectively adding quantitative continuous phase fluid into a continuous phase hole of a micro-fluidic chip and adding quantitative discrete phase samples into a discrete phase hole of the micro-fluidic chip; starting an air source power device and an air pressure controller to generate liquid drops in the microfluidic chip; after the droplets are generated, the pressure controller is closed, and a fixed amount of emulsion can be removed from the droplet outlet hole by using the pipette. In addition, the technical effects of the microfluidic chip are also included due to the inclusion of the microfluidic chip, and are not described in detail herein.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification.

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a chip board of a microfluidic chip according to an embodiment of the present invention;

FIG. 2 is an enlarged schematic view of FIG. 1 at A;

fig. 3 is a schematic diagram of a droplet preparation system according to an embodiment of the present invention.

10. A microfluidic chip; 11. a chip board; 111. continuous phase pore; 112. discrete phase holes; 113. a droplet outlet hole; 114. a first flow passage; 115. a second flow passage; 116. an intersection; 117. a first circuitous channel segment; 118. a second circuitous channel segment; 119. a gradual change channel section; 13. a first sample introduction pipe; 14. a second sample injection pipe; 15. a sample outlet pipe; 16. a first filter structure; 17. a second filter structure; 20. a clamping plate; 30. sealing the base plate; 31. and (6) connecting the interfaces.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

Referring to fig. 1 to 3, fig. 1 illustrates a schematic structural diagram of a chip board 11 of a microfluidic chip 10 according to an embodiment of the present invention; FIG. 2 illustrates an enlarged view of FIG. 1 at A; fig. 3 illustrates a schematic diagram of a droplet preparation system according to an embodiment of the present invention. An embodiment of the present invention provides a micro-fluidic chip 10, the micro-fluidic chip 10 includes a chip board 11. The chip plate 11 is provided with a continuous phase hole 111, a discrete phase hole 112, a droplet outlet hole 113, a first channel 114 and a second channel 115. The continuous phase hole 111 communicates with a middle portion of the second flow passage 115 through the first flow passage 114. The discrete phase hole 112 is connected to the droplet outlet hole 113 via a second flow channel 115. The first flow channel 114 is provided with a first circuitous channel section 117, and the second flow channel 115 is provided with a second circuitous channel section 118 from one end connected with the discrete phase hole 112 to the middle part of the second flow channel 115.

In the microfluidic chip 10, on one hand, the first flow channel 114 is provided with the first circuitous channel section 117, the first circuitous channel section 117 is beneficial to fully and uniformly mixing the continuous phase fluid and can play a role in stabilizing the flow, and similarly, the second circuitous channel section 118 is also beneficial to fully and uniformly mixing the discrete phase fluid and can play a role in stabilizing the flow; on the other hand, the length of the path from the continuous phase hole 111 to the intersection 116 of the first flow channel 114 and the second flow channel 115 can be adjusted by changing the shape of the first bypass channel section 117 and the length of the path from the discrete phase hole 112 to the intersection 116 can be adjusted by changing the shape of the second bypass channel section 118 without increasing the volume size of the chip plate 11, and the shear stress when two phases are in contact can be controlled by controlling the length of the path from the continuous phase hole 111 to the intersection 116 and the length of the path from the discrete phase hole 112 to the intersection 116, so that droplets with uniform size (for example, water-in-oil (W/O) droplets with an oil-water ratio close to 1: 1) can be stably generated at the intersection 116 after the dispersed phase fluid enters the microchannel under the shear stress of the continuous phase fluid.

It should be noted that the intersection 116 may be an intersection (as shown in fig. 2) or a T-shaped intersection. When the intersection 116 is an intersection, the first flow channels 114 are distributed on both sides of the second flow channel 115, and the first flow channels 114 flow outwards in two paths after entering from the continuous phase hole 111 and are merged with the second flow channel 115 at the intersection. When the intersection 116 is a T-shaped intersection, the first flow channels 114 are distributed on one side of the second flow channel 115, and the first flow channels 114 and the second flow channel 115 are converged to form the T-shaped intersection.

Further, the first detour channel section 117 is a detour channel having an S-shape, C-shape, Z-shape or L-shape, and the second detour channel section 118 is a detour channel having an S-shape, C-shape, Z-shape or L-shape. It is understood that the first detour channel segment 117 and the second detour channel may have other shapes, and are not limited herein.

Referring again to fig. 1-3, in one embodiment, the microfluidic chip 10 further includes a bottom cover plate (not shown). The continuous phase hole 111, the discrete phase hole 112, the droplet liquid outlet hole 113, the first flow channel 114 and the second flow channel 115 are formed by penetrating one side surface of the chip board 11 to the other side surface of the chip board 11, and the bottom cover plate is stacked under the chip board 11 to close the bottom surface of the chip board 11. So, when manufacturing, adopt for example the mode of moulding plastics a little and obtain chip board 11 after, with the bottom cover plate fold establish connect in chip board 11 the below so that chip board 11 the bottom surface seal can for chip board 11 forms semi-enclosed structure, avoids the fluid to flow down from chip board 11's bottom surface, the production of being convenient for simultaneously.

It is understood that it is also possible to arrange the continuous phase hole 111, the discrete phase hole 112, the droplet outlet hole 113, the first channel 114 and the second channel 115 not extending from one side of the chip board 11 to the other side of the chip board 11, but extending into the chip board 11, and thus there is no need to stack a connecting bottom cover plate under the chip board 11.

It is understood that the continuous phase hole 111, the discrete phase hole 112 and the droplet discharging hole 113 may extend from one side surface of the chip board 11 to the other side surface of the chip board 11, and the first flow channel 114 and the second flow channel 115 may not extend from one side surface of the chip board 11 to the other side surface of the chip board 11 but only extend into the chip board 11.

In one embodiment, the bottom cover plate is bonded, welded, screwed, riveted, pinned or snapped to the chip board 11.

The bonding mode of the bottom cover plate and the chip plate 11 is specifically hot-press bonding, ultrasonic bonding, solvent bonding and the like, and is not limited herein, the bottom cover plate is connected with the chip plate 11 by adopting the bonding mode, so that the bottom cover plate and the chip plate 11 can be combined into a whole, and the assembly efficiency is high.

As an example, the chip board 11 may be processed by using a polymer such as COC, COP, PC, PMMA, PS, etc., and the processing method is generally injection molding. In addition, the bottom cover plate can be firmly combined with the chip board 11 when the bottom cover plate is made of the same material as the chip board 11, and certainly, the bottom cover plate and the chip board 11 can be made of different materials without limitation.

In addition, when the chip board 11 is made of an intrinsically hydrophilic plate, it is also possible to modify the inner surfaces of the first flow channel 114 and the second flow channel 115 to have hydrophobic surfaces.

The bottom cover plate and the chip plate 11 are transparent plates. When the bottom cover plate and the chip plate 11 are transparent plates, the microfluidic chip 10 can be fixedly placed on the holding plate 20, and the holding plate 20 carrying the microfluidic chip 10 is directly placed under a microscope for observing the generation of droplets, without configuring or designing an expensive observation and detection system.

In addition, the holding plate 20 may be a transparent plate for observing the generation of droplets under a microscope. The clamping plate 20 may be quickly mass produced, for example by machining, for placement on a droplet generation receiving instrument.

In one embodiment, the chip plate 11 further has a first sample inlet 13 connected to the continuous phase hole 111, a second sample inlet 14 connected to the discrete phase hole 112, and a sample outlet 15 connected to the droplet outlet 113. The first sample inlet pipe 13, the second sample inlet pipe 14 and the sample outlet pipe 15 are all arranged on the side surface of the chip board 11, which is far away from the bottom cover plate. Therefore, the first sample injection pipe 13 is convenient to connect with the continuous phase gas circuit on one hand, and can be used for storing continuous phase liquid on the other hand, and the continuous phase gas circuit applies pressure to press the continuous phase liquid stored in the first sample injection pipe 13 into the continuous phase hole 111 during operation. Similarly, the second sampling pipe 14 is connected to the discrete phase gas path on the one hand, and on the other hand can be used for storing discrete phase liquid, and the discrete phase liquid stored in the second sampling pipe 14 is pressed into the discrete phase hole 112 by applying pressure to the discrete phase gas path during operation.

In infringement comparison, the "first sample inlet 13" may be a part of the chip board 11, that is, the "first sample inlet 13" and the "other part of the chip board 11" are integrally formed; the first sample inlet tube 13, which may be a separate member from the rest of the chip plate 11, may be manufactured separately and then integrated with the rest of the chip plate 11. As shown in FIG. 3, in one embodiment, the "first sample inlet 13" is a part of the "chip board 11" that is integrally formed. In addition, the second sample inlet tube 14 and the sample outlet tube 15 are similar to the first sample inlet tube 13, and are not described in detail herein.

Specifically, the volume of the first containing space formed by the first sample injection tube 13 communicating with the continuous phase hole 111 is controlled to be in the range of 2 μ L-100 μ L, and the volume of the second containing space formed by the second sample injection tube 14 communicating with the discrete phase hole 112 is controlled to be in the range of 2 μ L-100 μ L. In this way, in a specific test, for example, a pipette is used to quantitatively add a sample into the corresponding first accommodating space and second accommodating space, and gas with a certain pressure is respectively introduced into the first sample inlet tube 13 and the second sample inlet tube 14, so that the continuous-phase fluid stored in the first accommodating space and the discrete-phase fluid stored in the second accommodating space are mixed, and the number of generated droplets is selectable from hundreds to hundreds of thousands according to specific requirements.

In one embodiment, the end of second channel 115 that connects to droplet exit orifice 113 includes a tapered channel section 119. The size of the diameter of the gradual channel section 119 increases gradually in the direction close to the droplet outlet opening 113. Thus, the gradually-widened channel at the outlet of the second flow channel 115 can enable the generated micro-droplets to be discharged in order, and avoid the micro-droplets from being crushed and broken and fused.

Referring to fig. 1 to 3 again, in one embodiment, the microfluidic chip 10 further includes a first filter structure 16 and a second filter structure 17. The first filtering structure 16 is disposed at the sample inlet end of the first flow channel 114, and the second filtering structure 17 is disposed at the sample inlet end of the second flow channel 115. Therefore, the impurities possibly contained in the continuous phase fluid and the discrete phase fluid can be filtered, and the possibility of blocking the pipeline is reduced. Specifically, the first filter structure 16 and the second filter structure 17 may be cylindrical, triangular prism, conical, etc., and different shapes and different size arrangements may achieve different filtering effects.

In one embodiment, the number of the continuous phase hole 111, the discrete phase hole 112, the droplet outlet hole 113, the first flow channel 114, and the second flow channel 115 is two or more. The two or more continuous phase holes 111 and the two or more first channels 114 are respectively arranged corresponding to the two or more droplet outlet holes 113. More than two discrete phase holes 112 and more than two second flow channels 115 are respectively arranged corresponding to more than two microdroplet liquid outlet holes 113 one by one. Thus, when the continuous phase hole 111, the discrete phase hole 112, the droplet outlet hole 113, the first flow channel 114 and the second flow channel 115 are all one, they are equivalent to a droplet preparation channel; when the number is two or more, it corresponds to two or more droplet preparing channels. When more than two droplet preparation channels work synchronously, more droplets can be prepared more efficiently, and the production efficiency is higher; in addition, more than two kinds of droplets can be prepared synchronously, and the independence is better.

Furthermore, the number of the continuous phase holes 111, the discrete phase holes 112, the droplet discharging holes 113, the first flow channel 114 and the second flow channel 115 is eight, which is equivalent to eight droplet preparation channels, and the eight droplet preparation channels are sequentially arranged at intervals and form a row. Droplet generation for 1-8 passes can be performed selectively and simultaneously. Can prevent sample cross contamination and meet the requirement of high-flux sample preparation.

Referring to fig. 1 to 3, in one embodiment, a droplet preparation system includes a microfluidic chip 10 according to any of the above embodiments, a pneumatic controller (not shown), and an air source power device (not shown). The gas source power equipment is used for respectively introducing gas into the continuous phase hole 111 and the discrete phase hole 112, and the gas pressure controller is used for controlling the gas pressure introduced into the continuous phase hole 111 and the gas pressure introduced into the discrete phase hole 112.

When the micro-droplet preparation system works, a trace quantitative pipette is used for respectively adding quantitative continuous phase fluid into a continuous phase hole 111 of the micro-fluidic chip 10 and adding quantitative discrete phase samples into a discrete phase hole 112 of the micro-fluidic chip 10; starting an air source power device and an air pressure controller to generate liquid drops in the microfluidic chip 10; after the droplet is formed, the pressure controller is closed and a measured amount of emulsion is removed from droplet outlet 113 using a pipette. In addition, since the microfluidic chip 10 is included, the technical effects of the microfluidic chip 10 are also included, and are not described herein again.

Specifically, the droplet preparation system also includes a top cover plate. The top cover plate is provided with a first avoidance hole, a second avoidance hole and a third avoidance hole which respectively correspond to the first sample inlet pipe 13, the second sample inlet pipe 14 and the sample outlet pipe 15. The first sample inlet pipe 13 is disposed in the first avoiding hole, the second sample inlet pipe 14 is disposed in the second avoiding hole, the sample outlet pipe 15 is disposed in the third avoiding hole, the top cover plate is disposed on the chip plate 11 to seal and close the upper surface of the chip plate 11, such that the first flow channel 114 and the second flow channel 115 penetrating through the chip plate 11 are respectively sealed by the bottom cover plate and the top cover plate disposed at both sides of the chip plate 11, such that air tightness is ensured, and in addition, after the air source power device respectively introduces air into the first sample inlet pipe 13 and the second sample inlet pipe 14, the continuous phase fluid in the first sample inlet pipe 13 can be pushed to the intersection 116, and the discrete phase fluid in the second sample inlet pipe 14 can be pushed to the intersection 116, and the continuous phase fluid and the discrete phase fluid are mixed at the intersection 116 to generate droplets, and the generated droplets continuously move forward to be discharged from the droplet outlet hole 113, the risk of splashing contaminated samples in the process of generating micro-droplets can be avoided.

In addition, the droplet preparation system also includes a sealing pad 30. The sealing pad 30 is disposed between the air outlet end of the air source power equipment and the first sample inlet pipe 13, the second sample inlet pipe 14 and the sample outlet pipe 15, the sealing pad 30 is specifically, for example, a silica gel plate, the sealing pad 30 is provided with a plurality of butt joints 31, the butt joints 31 are respectively disposed corresponding to the first sample inlet pipe 13, the second sample inlet pipe 14 and the sample outlet pipe 15, and thus the sealing pad 30 is favorable for realizing that the air outlet end of the air source power equipment is respectively in good butt joint with the first sample inlet pipe 13 and the second sample inlet pipe 14.

Wherein, the air source power equipment can adopt a nitrogen cylinder, and can also use a pressure pump, an injection pump and the like.

In one embodiment, a method for designing the microfluidic chip 10 according to any of the above embodiments includes the following steps: the junction 116 is formed by the junction of the first channel 114 and the second channel 115, and the size uniformity of the droplets generated at the junction 116 is controlled by adjusting the path length from the continuous phase hole 111 to the junction 116 and the path length from the discrete phase hole 112 to the junction 116.

In the design method of the micro-fluidic chip 10, the micro-droplets are generated by adopting a positive pressure type and cross method according to the design scheme of the micro-fluidic chip 10, and the shear stress when two phases are contacted can be controlled by setting the length of the continuous phase hole 111 reaching the intersection 116 and the length of the discrete phase hole 112 reaching the intersection 116, so that the micro-droplets with uniform size (such as water-in-oil (W/O) droplets with the oil-water ratio close to 1: 1) can be stably generated at the intersection 116 under the shear stress action of the continuous phase fluid after the dispersed phase fluid enters the micro-channel. In addition, because the microfluidic chip 10 is adopted, the technical effects of the microfluidic chip 10 are also included, and the details are not repeated herein.

Note that the two-phase (continuous and discrete phase) channel width at the droplet-generating intersection 116 determines the magnitude of the generated droplet size. That is, when the channel width (also indicated by the inner diameter) of the first flow channel 114 at the intersection 116 and the channel width of the second flow channel 115 are adjusted, the target droplet size range can be adjusted accordingly.

In addition, the diameter of the generated liquid drop can be continuously adjusted in a wide range according to the change of two-phase different sampling pressure ratio. That is, the diameter of the generated liquid drop can be adjusted correspondingly by adjusting the injection pressure ratio of two phases.

As an example, the channel width (also indicated by the inner diameter) of the first channel 114 and the channel width of the second channel 115 at the intersection 116 of the present design are 101 μm and 91 μm, respectively, and the target droplet size under specific sample introduction conditions is in the range of 80 μm to 130 μm. Further, as the diameter of the generated micro-droplets is linearly related to the two-phase injection pressure ratio, when the two-phase injection pressure is increased, the diameter of the generated micro-droplets is correspondingly increased within the range of 80-130 μm.

It should be noted that the principle of generating droplets by the microfluidic chip 10 is to introduce two immiscible fluids into a flow channel of the microfluidic chip 10, wherein one of the fluids is a discrete phase and serves as a sheared phase fluid, and the other fluid is a continuous phase and serves as a shearing fluid, and the discrete phase fluid is separated into discrete droplets by the continuous phase fluid in an intersection region of the two fluids.

Specifically, after the continuous phase fluid and the discrete phase fluid respectively enter the corresponding flow channels in the microfluidic chip 10, interfaces of the continuous phase fluid and the discrete phase fluid are formed at the junctions of the different flow channels. The discrete phase fluid moves forward synchronously with the continuous phase fluid under the pushing of external force and the shearing force of the continuous phase fluid. When the interfacial tension at the interface is insufficient to maintain the shear force applied to the discrete phase fluid by the continuous phase fluid, the discrete phase fluid breaks to create individual microscopic volume elements, i.e., droplets, surrounded by the continuous phase fluid.

For example, in the case where the continuous phase fluid is oil and the discrete phase fluid is water, an oil/water interface is formed at the oil-water junction, the aqueous phase moves forward in synchronization with the oil phase under the urging of an external force and the shearing force of the oil phase, and the aqueous phase breaks to form individual droplets surrounded by the oil phase when the interfacial tension at the oil/water interface is insufficient to maintain the shearing force applied to the aqueous phase by the oil phase.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only represent some embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Claims

1. A microfluidic chip, comprising:

the chip board is provided with a continuous phase hole, a discrete phase hole, a droplet liquid outlet hole, a first flow channel and a second flow channel, the continuous phase hole is communicated with the middle part of the second flow channel through the first flow channel, the discrete phase hole is communicated with the droplet liquid outlet hole through the second flow channel, the first flow channel is provided with a first roundabout channel section, and a second roundabout channel section is arranged from one end, connected with the discrete phase hole, of the second flow channel to the middle part of the second flow channel.

2. The microfluidic chip according to claim 1, wherein the first tortuous channel segment is an S-shaped, C-shaped, Z-shaped or L-shaped tortuous channel, and the second tortuous channel segment is an S-shaped, C-shaped, Z-shaped or L-shaped tortuous channel.

3. The microfluidic chip according to claim 1, further comprising a bottom cover plate, wherein the continuous phase hole, the discrete phase hole, the droplet outlet hole, the first flow channel and the second flow channel are all formed by penetrating one side surface of the chip board to the other side surface of the chip board, and the bottom cover plate is stacked under the chip board to close the bottom surface of the chip board.

4. The microfluidic chip according to claim 3, wherein the bottom cover plate is bonded, welded, screwed, riveted, pinned, or snapped to the chip board.

5. The microfluidic chip according to claim 3, wherein the chip board further comprises a first sample inlet connected to the continuous phase hole, a second sample inlet connected to the discrete phase hole, and a sample outlet connected to the droplet outlet; the first sample inlet pipe, the second sample inlet pipe and the sample outlet pipe are arranged on the chip board and deviate from the side face of the bottom cover plate.

6. The microfluidic chip according to claim 3, wherein the bottom cover plate and the chip plate are transparent plates.

7. The microfluidic chip according to claim 1, wherein an end of the second channel connected to the droplet outlet hole includes a gradually changing channel section, and a diameter of the gradually changing channel section gradually increases in a direction close to the droplet outlet hole.

8. The microfluidic chip according to claim 1, further comprising a first filter structure and a second filter structure, wherein the first filter structure is disposed at the sample inlet end of the first flow channel, and the second filter structure is disposed at the sample inlet end of the second flow channel.

9. The microfluidic chip according to any one of claims 1 to 8, wherein the number of the continuous phase wells, the discrete phase wells, the droplet outlet wells, the first flow channel, and the second flow channel is two or more; the more than two continuous phase holes and the more than two first flow channels are respectively arranged corresponding to the more than two microdroplet liquid outlet holes one by one; more than two discrete phase holes and more than two second flow channels are respectively arranged corresponding to more than two microdroplet liquid outlet holes one to one.

10. A droplet preparation system comprising a microfluidic chip according to any one of claims 1 to 8, a gas pressure controller and a gas source power device, wherein the gas source power device is used for respectively introducing gas into the continuous phase wells and the discrete phase wells, and the gas pressure controller is used for controlling the gas pressure introduced into the continuous phase wells and the gas pressure introduced into the discrete phase wells.