Microfluidic chip

Abstract

The invention provides a micro-fluidic chip, which comprises a first carrier plate and a second carrier plate, one side surface of the first carrier plate is provided with a micro-channel, a first inlet and a second inlet, the first inlet and the second inlet are communicated with the micro-channel, the micro-channel comprises a dispersed phase channel, an emulsification channel and a continuous phase channel, the dispersed phase channel is communicated with the first inlet, the emulsification channel is communicated with the second inlet, and the continuous phase channel is communicated with the second inlet. The continuous-phase flow channel is communicated with the second inlet, the two ends of the emulsifying flow channel are communicated with the dispersed-phase flow channel and the continuous-phase flow channel respectively, and the depth of the emulsifying flow channel is smaller than that of the continuous-phase flow channel, so that a stepped structure is formed at the intersection of the emulsifying flow channel and the continuous-phase flow channel; the second carrier plate is connected with the surface of the side, provided with the micro-channels, of the first carrier plate, the first carrier plate or the second carrier plate is further provided with an outlet communicated with the continuous phase channels, and the liquid drops flow out through the outlet. The micro-fluidic chip can generate liquid drops with high particle size uniformity, and has relatively low process manufacturing requirements.

Description

Technical Field

[0001] The present invention relates to the field of microfluidic technology, and in particular to a microfluidic chip. Background Art

[0002] Microfluidics is a technology that manipulates fluids at the micrometer scale. Droplet microfluidics, as an important branch of microfluidic chip research, has been developed in recent years based on the traditional microfluidic system. Droplet microfluidics technology can prepare picoliter droplets with good monodispersity. Droplets can wrap different samples, including chemical reagents, micro-nanoparticles, cells, DNA, and microorganisms. This enables droplets to be used as independent reaction units for qualitative or quantitative detection. It has the advantages of small sample requirements, portability, and high integration. It is currently widely used in the biomedical field.

[0003] The preparation process of microfluidic chips usually involves bonding of multiple carriers. During the bonding process, the microchannels in the multiple carriers need to be aligned to ensure the flow of the microchannels. However, since the width of the microchannels is in the micrometer range, it is difficult to align the microchannels, which increases the difficulty of manufacturing microfluidic chips and reduces the yield of microfluidic chips. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, the present invention provides a microfluidic chip, comprising:

[0006] A first carrier plate, wherein a surface of one side of the first carrier plate has a microfluidic channel, and a first inlet and a second inlet communicated with the microfluidic channel, the microfluidic channel includes a dispersed phase flow channel, an emulsified flow channel and a continuous phase flow channel, the dispersed phase flow channel is communicated with the first inlet, the continuous phase flow channel is communicated with the second inlet, both ends of the emulsified flow channel are communicated with the dispersed phase flow channel and the continuous phase flow channel respectively, the depth of the emulsified flow channel is less than the depth of the continuous phase flow channel, so as to form a stepped structure at the intersection of the emulsified flow channel and the continuous phase flow channel;

[0007] A second carrier plate is arranged opposite to the first carrier plate, and the second carrier plate is connected to a side surface of the first carrier plate provided with the microchannel; the first carrier plate or the second carrier plate is also provided with an outlet connected to the continuous phase flow channel.

[0008] In one embodiment, the depth of the dispersed phase flow channel is greater than the depth of the emulsification flow channel.

[0009] In one embodiment, the dispersed phase flow channel has the same depth as the continuous phase flow channel.

[0010] In one embodiment, the first carrier has a first through hole and a second through hole penetrating the first carrier, the first through hole constituting the first inlet, and the second through hole constituting the second inlet;

[0011] The first carrier plate further has a third through hole penetrating the first carrier plate, and the third through hole constitutes the outlet; or the second carrier plate has a fourth through hole penetrating the second carrier plate, and the fourth through hole constitutes the outlet.

[0012] In one embodiment, the continuous phase flow channel comprises a continuous phase transmission flow channel and a droplet transmission flow channel that are interconnected; the continuous phase transmission flow channel is connected to the second inlet;

[0013] One end of the emulsification channel away from the dispersed phase channel is connected to the side wall of the droplet transport channel, and the intersection of the emulsification channel and the droplet transport channel forms the stepped structure; the droplet transport channel is connected to the outlet.

[0014] In one embodiment, in a direction perpendicular to the extension direction of the continuous phase flow channel, the cross-sectional area of ​​the continuous phase transport flow channel is larger than the cross-sectional area of ​​the droplet transport flow channel.

[0015] In one embodiment, the microfluidic chip includes a plurality of emulsification channels arranged in sequence; the dispersed phase channel includes a main transmission channel and a distribution channel that are interconnected, the end of the main transmission channel facing away from the distribution channel is connected to the first inlet, and the end of the emulsification channel facing away from the continuous phase channel is connected to the side wall of the distribution channel.

[0016] In one embodiment, the multiple emulsification channels have the same size.

[0017] In one embodiment, along the extension direction of the distribution channel, the distribution channel has a middle position, and the main transmission channel is connected to the middle position to divide the distribution channel into two branches.

[0018] In one embodiment, the two branches are respectively a first branch and a second branch, and in a direction perpendicular to the extension of the dispersed phase flow channel, a cross-sectional area of ​​the main transmission flow channel is greater than or equal to the sum of the cross-sectional areas of the first branch and the second branch.

[0019] In one embodiment, the depth difference between the continuous phase flow channel and the emulsification flow channel is 15 μm to 1000 μm.

[0020] In one embodiment, the depth of the continuous phase flow channel is 20 μm to 1050 μm, and the depth of the emulsification flow channel is 5 μm to 50 μm.

[0021] The technical solution of the present invention has the following advantages:

[0022] 1. The microfluidic chip provided by the present invention, by setting all the microchannels on the first carrier, does not involve alignment between the microchannels in the process of connecting the first carrier and the second carrier, thereby reducing the difficulty of alignment, thereby reducing the difficulty of manufacturing the microfluidic chip, improving the yield of the microfluidic chip, and reducing the manufacturing cost. By limiting the depth of the emulsified flow channel to be less than the depth of the continuous phase flow channel, the dispersed phase liquid is step-emulsified at the intersection of the emulsified flow channel and the continuous phase flow channel to generate droplets with high particle size uniformity. The microfluidic chip is also provided with an outlet, and the continuous phase liquid and the generated droplets are transmitted to the outside through the outlet, reducing the risk of fusion between droplets caused by accumulation of droplets inside the microfluidic chip, thereby improving the uniformity of the droplet particle size.

[0023] 2. The microfluidic chip provided by the present invention limits the depth of the dispersed phase flow channel to be greater than the depth of the emulsified flow channel, so that the dispersed phase liquid can more easily enter the dispersed phase flow channel and flow smoothly in the dispersed phase flow channel, thereby reducing the required pressure. This reduces the force acting on the first carrier plate and the second carrier plate, which is beneficial to maintaining the overall structure of the microfluidic chip.

[0024] 3. In the microfluidic chip provided by the present invention, the dispersed phase flow channel and the continuous phase flow channel have the same depth. In this case, the entire microchannel has two depths, which reduces the difficulty of mold manufacturing process and injection molding, thereby reducing the difficulty of preparing the microchannel.

[0025] 4. In the microfluidic chip provided by the present invention, the cross-sectional area of ​​the continuous phase transmission channel is larger than the cross-sectional area of ​​the droplet transmission channel, which not only facilitates the continuous phase liquid to enter the droplet transmission channel from the continuous phase transmission channel, but also facilitates the generation of droplets at the intersection of the emulsification channel and the droplet transmission channel.

[0026] 5. The microfluidic chip provided by the present invention has a microchannel provided with a plurality of emulsification channels arranged in sequence, and the plurality of emulsification channels can generate droplets simultaneously, thereby improving the droplet generation efficiency.

[0027] 6. The microfluidic chip provided by the present invention limits the sizes of multiple emulsification channels to be the same, so that the droplets produced by different emulsification channels have a high uniformity in particle size.

[0028] 7. In the microfluidic chip provided by the present invention, the cross-sectional area of ​​the main transmission channel is greater than or equal to the sum of the cross-sectional areas of the first branch and the second branch, so that the dispersed phase liquid can enter the two branches from the main transmission channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 An exploded view of a microfluidic chip provided in an embodiment of the present invention;

[0031] Figure 2 for Figure 1 Schematic diagram of the structure of the microfluidic channel;

[0032] Figure 3 for Figure 1 A depth schematic diagram of the dispersed phase flow channel, the emulsified flow channel, and the continuous phase flow channel;

[0033] Figure 4 for Figure 1 A cross-sectional view of the intersection of the emulsification flow channel and the continuous phase flow channel;

[0034] Figure 5 for Figure 1 A schematic structural diagram of a second carrier board;

[0035] Description of reference numerals:

[0036] 1-first carrier plate; 11-microchannel; 111-dispersed phase channel; 111a-main transport channel; 111b-distribution channel; 112-emulsification channel; 113-continuous phase channel; 113a-continuous phase transport channel; 113b-droplet transport channel; 12-first through hole; 13-second through hole; 14-receiving groove; 2-second carrier plate; 21-fourth through hole; 3-droplet; 4-first connecting part; 5-second connecting part; 6-third connecting part. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0038] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0039] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] See also Figure 1 , this embodiment provides a microfluidic chip, comprising:

[0041] A first carrier plate 1 has a microchannel 11 and a first inlet and a second inlet connected to the microchannel 11 on one side surface of the first carrier plate 1. Figure 2-Figure 3 , the microchannel 11 includes a dispersed phase channel 111, an emulsified flow channel 112 and a continuous phase channel 113, the first inlet is connected to one end of the dispersed phase channel 111 to inject dispersed phase liquid into the dispersed phase channel 111, the second inlet is connected to one end of the continuous phase channel 113 to inject continuous phase liquid into the continuous phase channel 113, the two ends of the emulsified flow channel 112 are connected to the dispersed phase channel 111 and the continuous phase channel 113 respectively, and the depth h of the emulsified flow channel 112 is less than the depth H1 of the continuous phase channel 113;

[0042] The second carrier plate 2 is arranged opposite to the first carrier plate 1, and the second carrier plate 2 is bonded to the side surface of the first carrier plate 1 provided with the microfluidic channel 11; the first carrier plate 1 or the second carrier plate 2 is also provided with an outlet connected to the continuous phase flow channel 113, and the outlet is used for the droplets to flow out. It should be noted that "the second carrier plate 2 is bonded to the side surface of the first carrier plate 1 provided with the microfluidic channel 11" here means that the second carrier plate 2 is fixedly connected to the side surface of the first carrier plate 1 provided with the microfluidic channel 11, which can be achieved by bonding, clamping or other fixing methods.

[0043] By arranging all the microchannels 11 on the first carrier 1, the alignment between the microchannels 11 is not involved in the bonding process between the first carrier 1 and the second carrier 2, thereby reducing the difficulty of alignment, thereby reducing the difficulty of manufacturing the microfluidic chip, improving the yield of the microfluidic chip, and reducing the manufacturing cost. Figure 4By limiting the depth of the emulsification channel 112 to be smaller than the depth of the continuous phase channel 113, the dispersed phase liquid is step-emulsified at the intersection of the emulsification channel 112 and the continuous phase channel 113 where there is a depth difference, so as to generate droplets 4 with high size uniformity. The larger uniformity of the droplet particle size is beneficial to improving the accuracy of the detection results.

[0044] In the above-mentioned microfluidic chip, the dispersed phase liquid enters the dispersed phase flow channel 111 from the first inlet, and then enters the emulsification flow channel 112; the continuous phase liquid enters the continuous phase flow channel 113 from the second inlet, and flows along the continuous phase flow channel 113 to the outlet, that is, the setting of the outlet makes the continuous phase liquid fluid; the dispersed phase liquid generates droplets through step emulsification at the intersection of the emulsification flow channel 112 and the continuous phase flow channel 113, and the droplets flow out of the outlet together with the flowing continuous phase liquid, which reduces the risk of droplets merging due to accumulation of droplets inside the microfluidic chip, thereby improving the uniformity of droplet particle size. Specifically, by controlling the flow rate of the dispersed phase liquid entering the dispersed phase channel 111, the droplet generation rate can be controlled; by controlling the flow rate of the continuous phase liquid entering the continuous phase channel 113, the speed of the droplets flowing out of the microfluidic chip can be controlled; by regulating the flow rates of the dispersed phase liquid and the continuous phase liquid entering the microfluidic channel 11, the droplets generated in the continuous phase channel 113 can be timely transmitted to the outside of the microfluidic chip, thereby reducing the risk of droplet accumulation inside the microfluidic chip, thereby improving the uniformity of the droplet particle size.

[0045] In one embodiment, see Figure 2 The first carrier plate 1 has a first through hole 12 penetrating the first carrier plate 1, the first through hole 12 constituting the first inlet, and the first through hole 12 is connected to one end of the dispersed phase flow channel 111. In another embodiment, one end of the dispersed phase flow channel extends transversely to the side of the first carrier plate to form the first inlet.

[0046] In one embodiment, see Figure 2 , the first carrier plate 1 has a second through hole 13 penetrating the first carrier plate 1, the second through hole constituting the second inlet, and the second through hole 13 is connected to one end of the continuous phase flow channel 113. In another embodiment, one end of the continuous phase flow channel extends laterally to the side of the first carrier plate to form a second inlet. The arrangement of the first inlet and the second inlet can be selected as needed.

[0047] In one embodiment, the first carrier has a third through hole that passes through the first carrier, and the third through hole constitutes the outlet. The third through hole is connected to the end of the continuous phase flow channel away from the second inlet. At this time, the first carrier can be directly bonded to the second carrier without involving the alignment step of the first carrier and the second carrier, which effectively reduces the manufacturing difficulty of the microfluidic chip, effectively improves the yield of the microfluidic chip, and effectively reduces the manufacturing cost.

[0048] In another embodiment, see Figure 5 , the second carrier 2 has a fourth through hole 21 penetrating the second carrier 2, the fourth through hole 21 constituting the outlet, the fourth through hole 21 being connected to the end of the continuous phase channel 113 away from the second inlet, the fourth through hole 21 being larger than the width of the continuous phase channel 113; when the first carrier 1 and the second carrier 2 are bonded, the fourth through hole 21 needs to be aligned with the end of the continuous phase channel 113 away from the second inlet, and since the fourth through hole has a larger size relative to the microchannel 11, the alignment accuracy requirement is relatively low, and it is sufficient to ensure that the orthographic projection of the end of the continuous phase channel 113 away from the second inlet on the second carrier 2 is located within the fourth through hole, so the manufacturing difficulty of the microfluidic chip is also relatively low. Optionally, see Figure 1 A receiving groove 14 is also provided on one side surface of the first carrier plate provided with the microchannel. The receiving groove 14 is located at one end of the continuous phase flow channel 113 away from the second inlet and is connected to the continuous phase flow channel 113. The depth of the receiving groove 14 can be the same as the depth of the continuous phase flow channel 113. The inner diameter of the fourth through hole is greater than or equal to the inner diameter of the receiving groove 14. When the first carrier plate 1 and the second carrier plate 2 are bonded, it is only necessary that the orthographic projection of the receiving groove 14 on the second carrier plate is located in the fourth through hole or coincides with the fourth through hole, and the alignment accuracy requirement is relatively low.

[0049] In other embodiments, the end of the continuous phase flow channel away from the second inlet extends laterally to the side of the first carrier to form the outlet. In this case, the first carrier can be directly bonded to the second carrier without involving the alignment step of the first carrier and the second carrier, which effectively reduces the manufacturing difficulty of the microfluidic chip, effectively improves the yield of the microfluidic chip, and effectively reduces the manufacturing cost. The location of the outlet can be selected as needed.

[0050] It should be noted that the "side surface of the first carrier" mentioned in the present application refers to the surface perpendicular to the extension direction of the first carrier; the microchannel is a groove with a smaller width and depth, and the depth of the microchannel mentioned in the present application refers to the depth of the groove, and the width of the microchannel mentioned in the present application refers to the width value at half the depth of the groove.

[0051] Furthermore, the microfluidic chip may also include a first connection portion 4 disposed at the first inlet, a second connection portion 5 disposed at the second inlet, and a third connection portion 6 disposed at the outlet, wherein the first connection portion, the second connection portion and the third connection portion all have through holes, the first connection portion is connected to the first inlet so that the first inlet is connected to the dispersed phase liquid supply end, the second connection portion is connected to the second inlet so that the second inlet is connected to the continuous phase liquid supply end, and the third connection portion is connected to the outlet so that the outlet is connected to the droplet receiving container. Figure 1 When the first inlet, the second inlet and the outlet are all through holes, the first connecting part, the second connecting part and the third connecting part are cylindrical, the first connecting part and the second connecting part are arranged on a side surface of the first carrier away from the second carrier, the third connecting part is arranged on a side surface of the first carrier away from the second carrier or on a side surface of the second carrier away from the first carrier, and the setting position of the third connecting part depends on the setting position of the outlet.

[0052] In one embodiment, the depth difference between the continuous phase flow channel 113 and the emulsification flow channel 112 may be 15 μm to 1000 μm, for example, the depth difference may be 15 μm, 25 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1000 μm. Figure 4 , the depth difference between the continuous phase flow channel 113 and the emulsification flow channel 112 is greater than or equal to the diameter of the droplets generated, otherwise it is easy to be blocked at the end of the emulsification flow channel 112 facing the continuous phase flow channel 113, which not only affects the uniformity of the particle size of the generated droplets, but also has an adverse effect on the generation efficiency of the droplets. If the depth difference is too large, the thickness of the first carrier plate 1 must be too large, otherwise the structural stability of the microchannel 11 cannot be guaranteed, which is not conducive to the miniaturization of the microfluidic chip; at the same time, the depth-to-width ratio of the microchannel prepared by the existing microchannel preparation process is within a certain range. When the depth of the microchannel changes, the width of the microchannel will also change accordingly. If the depth difference between the continuous phase flow channel 113 and the emulsification flow channel 112 is too large, the depth of the continuous phase flow channel 113 needs to be too large, and accordingly, the width of the continuous phase flow channel 113 will also be too large, which will greatly reduce the flow resistance of the continuous phase flow channel 113, which is not conducive to the pressure control of the step emulsification. The depth difference between the continuous phase flow channel 113 and the emulsification flow channel 112 is preferably 50 μm to 250 μm.

[0053] In one embodiment, the depth of the continuous phase flow channel 113 may be 20 μm to 1050 μm, and the depth of the emulsification flow channel 112 may be 5 μm to 50 μm. Exemplarily, the depth of the continuous phase flow channel 113 may be 20 μm, 50 μm, 100 μm, 125 μm, 150 μm, 175 μm, 200 μm, 225 μm, 250 μm, 275 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1050 μm, and the depth of the emulsification flow channel 112 is 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm. The depth of the continuous phase flow channel 113 is preferably 100 μm to 500 μm, more preferably 150 μm to 250 μm; the depth of the emulsification flow channel 112 is preferably 10 μm to 30 μm, more preferably 15 to 25 μm.

[0054] The basic principle of step emulsification is that in a microchannel with a depth difference, the dispersed phase liquid is subjected to different gradient shear forces at the depth difference, thereby generating droplets. Driven by pressure, the dispersed phase liquid enters the dispersed phase channel 111 and the continuous phase liquid enters the continuous phase channel 113.

[0055] In this embodiment, see Figure 3 , the depth H2 of the dispersed phase flow channel 111 is greater than the depth h of the emulsified flow channel 112. The depth of the emulsified flow channel 112 is small. When the depths of the dispersed phase flow channel 111 and the emulsified flow channel 112 are the same, the flow resistance of the dispersed phase flow channel 111 is large, and a large pressure is required to allow the dispersed phase liquid to enter the dispersed phase flow channel 111 and flow smoothly in the dispersed phase flow channel 111. At this time, the first carrier 1 and the second carrier 2 are subjected to a large force, which easily causes the first carrier 1 and the second carrier 2 to separate at the bonding position between the two, destroying the overall structure of the microfluidic chip, which is not conducive to the service life of the microfluidic chip. By limiting the depth of the dispersed phase flow channel 111 to be greater than the depth of the emulsified flow channel 112, the dispersed phase liquid is easier to enter the dispersed phase flow channel 111 and flow smoothly in the dispersed phase flow channel 111, reducing the required pressure, which reduces the force applied to the first carrier 1 and the second carrier 2, and is conducive to maintaining the overall structure of the microfluidic chip. Preferably, the dispersed phase flow channel 111 has the same depth as the continuous phase flow channel 113. In this case, the entire microchannel 11 has only two depths, which reduces the difficulty of mold manufacturing process and injection molding, thereby reducing the difficulty of preparing the microchannel 11.

[0056] In this embodiment, the continuous phase flow channel 113 includes a continuous phase transmission flow channel 113a and a droplet transmission flow channel 113b that are interconnected; the end of the continuous phase transmission flow channel 113a away from the droplet transmission flow channel 113b is connected to the second inlet, and is used to transmit the continuous phase liquid injected from the second inlet to the droplet transmission flow channel 113b; the end of the emulsification flow channel 112 away from the dispersed phase flow channel 111 is connected to the side wall of the droplet transmission flow channel 113b, and droplets are formed at the intersection of the emulsification flow channel 112 and the droplet transmission flow channel 113b; the end of the droplet transmission flow channel 113b away from the continuous phase transmission flow channel 113a is connected to the outlet, and is used to transport the generated droplets to the outside of the outlet; the outlet is connected to a droplet receiving container, and the droplets transmitted from the outlet are collected in the droplet receiving container.

[0057] Furthermore, in the direction perpendicular to the extension of the continuous phase flow channel, the cross-sectional area of ​​the continuous phase transmission flow channel 113a is larger than the cross-sectional area of ​​the droplet transmission flow channel 113b, which not only facilitates the continuous phase liquid to enter the droplet transmission flow channel 113b from the continuous phase transmission flow channel 113a, but also facilitates the generation of droplets at the intersection of the emulsification flow channel 112 and the droplet transmission flow channel 113b. Specifically, when the depth of the continuous phase transmission flow channel 113a is equal to the depth of the droplet transmission flow channel 113b, the width of the continuous phase transmission flow channel 113a is larger than the width of the droplet transmission flow channel 113b.

[0058] For further information, see Figure 4 , the depth of the droplet transport channel 113b is greater than or equal to 1.5 droplet diameters, so that the droplets being formed and the droplets just generated are separated in the depth direction of the droplet transport channel, so as to reduce the risk of droplet fusion caused by droplet accumulation in the droplet transport channel 113b, thereby improving the uniformity of the droplet diameter and facilitating the smooth outflow of the droplets. It should be noted that the droplet diameter described in this application refers to the diameter of the droplet.

[0059] In this embodiment, the microchannel 11 is provided with a plurality of emulsification channels 112 arranged in sequence; the dispersed phase channel 111 includes a main transmission channel 111a and a distribution channel 111b that are interconnected, the end of the main transmission channel 111a away from the distribution channel 111b is connected to the first inlet, and the end of the emulsification channel 112 away from the continuous phase channel 113 is connected to the side wall of the distribution channel 111b. Multiple emulsification channels 112 can generate droplets at the same time, thereby improving the droplet generation efficiency. The number of emulsification channels 112 can be selected as needed.

[0060] Furthermore, the sizes of the multiple emulsification channels 112 are the same, that is, the lengths, widths and depths of the multiple emulsification channels 112 are the same. The size of the emulsification channel 112 can affect the particle size of the generated droplets. By limiting the sizes of the multiple emulsification channels 112 to be the same, the droplets generated by different emulsification channels 112 have a higher particle size uniformity. At the same time, the size of the emulsification channel 112 will affect the flow resistance of the dispersed phase liquid in the emulsification channel 112. When the size difference of the multiple emulsification channels is too large, the difference in the flow resistance of the multiple emulsification channels will also be too large. At this time, the dispersed phase liquid from the distribution channel 111b will preferentially enter the emulsification channel with small flow resistance. The emulsification channel with too large flow resistance may not have dispersed phase liquid flowing into it, and thus droplets cannot be generated. Even if the dispersed phase liquid can enter the emulsification channel with too large flow resistance, the flow rate of the dispersed phase liquid in the emulsification channel is also small, resulting in a low efficiency of droplet generation in the emulsification channel, that is, the large size difference of the emulsification channel limits the droplet generation efficiency. By limiting the sizes of the multiple emulsification channels 112 to be the same, it is helpful to control the flow resistance of the multiple emulsification channels 112, thereby helping to control the droplet generation efficiency of the microfluidic chip.

[0061] In order to make the shapes and sizes of the multiple emulsification channels 112 the same, in one embodiment, the multiple emulsification channels 112 are perpendicular to the distribution channel 111b and the droplet transmission channel; in another embodiment, the distribution channel and the droplet transmission channel are parallel to each other, and both ends of each emulsification channel are symmetrical along the central axis of the distribution channel and the droplet transmission channel, and the emulsification channel is curved. Among them, when the multiple emulsification channels are perpendicular to the distribution channel and the droplet transmission channel, the structure of the emulsification channel is simpler and the processing difficulty of the microchannel is smaller. In other embodiments, the multiple emulsification channels 112 can also be arranged in other forms, and the spacing between the multiple emulsification channels 112 can be equal or unequal.

[0062] Furthermore, the distance between the ports of two adjacent emulsification channels 112 facing the droplet transport channel is greater than or equal to the diameter of the generated droplets, so as to reduce the risk of droplet fusion due to droplet accumulation in the droplet transport channel 113b, thereby improving the uniformity of droplet particle size.

[0063] In one embodiment, along the extension direction of the distribution channel 111b, the distribution channel 111b has a middle position, and the main transmission channel 111a is connected to the middle position to divide the distribution channel 111b into two branches, the two branches are respectively a first branch and a second branch, and in the extension direction perpendicular to the dispersed phase channel, the cross-sectional area of ​​the main transmission channel is greater than or equal to the sum of the cross-sectional areas of the first branch and the second branch, so that the dispersed phase liquid enters the two branches from the main transmission channel 111a. Specifically, when the depth of the main transmission channel 111a is the same as that of the two branches, the width of the main transmission channel 111a is greater than or equal to the sum of the widths of the first branch and the second branch. If the cross-sectional area of ​​the main transmission channel 111a is smaller than the sum of the cross-sectional areas of the two branches, it is not conducive to the continuous and stable entry of the dispersed phase liquid into the two branches, and thus is not conducive to the continuous and stable formation of droplets.

[0064] In one embodiment, the width of the emulsification channel 112 may be 10 μm-500 μm, such as 10 μm, 20 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm or 500 μm, preferably 20 μm-250 μm, more preferably 40 μm-80 μm. ; The width of the droplet transport channel 113b can be 20μm-5mm, such as 20μm, 50μm, 75μm, 100μm, 150μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, 1mm, 2mm, 3mm, 4mm or 5mm, preferably 100μm-1mm, more preferably 250μm-500μm.

[0065] In one embodiment, the dispersed phase liquid is an aqueous phase, and the continuous phase liquid is an oil phase, and the droplets obtained at this time are "water-in-oil" droplets; in other embodiments, the dispersed phase liquid is an oil phase, and the continuous phase liquid is an aqueous phase, and the droplets obtained at this time are "oil-in-water" droplets.

[0066] Below Figure 1 The process of generating droplets on the microfluidic chip is described as follows:

[0067] The dispersed phase liquid enters the main transmission channel 111a from the first through hole 12, and then enters the distribution channel 111b and the multiple emulsification channels 112 in sequence;

[0068] The continuous phase liquid enters the continuous phase transmission channel 113a through the second through hole 13, and then enters the droplet transmission channel 113b;

[0069] At the intersection of the emulsification channel 112 and the droplet transport channel 113b, the dispersed phase liquid is subjected to different gradient shear forces to generate droplets. The generated droplets are transported to the outside of the microfluidic chip through the fourth through hole 21 along with the flowing continuous phase liquid and are collected in a droplet receiving container.

[0070] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A microfluidic chip, characterized in that: include: A first carrier plate, wherein a surface of one side of the first carrier plate has a microfluidic channel, and a first inlet and a second inlet communicated with the microfluidic channel, the microfluidic channel includes a dispersed phase flow channel, an emulsified flow channel and a continuous phase flow channel, the dispersed phase flow channel is communicated with the first inlet, the continuous phase flow channel is communicated with the second inlet, both ends of the emulsified flow channel are communicated with the dispersed phase flow channel and the continuous phase flow channel respectively, the depth of the emulsified flow channel is less than the depth of the continuous phase flow channel, so as to form a stepped structure at the intersection of the emulsified flow channel and the continuous phase flow channel; A second carrier plate is arranged opposite to the first carrier plate, and the second carrier plate is connected to a side surface of the first carrier plate provided with the microchannel; the first carrier plate or the second carrier plate is also provided with an outlet connected to the continuous phase flow channel.

2. The microfluidic chip according to claim 1, characterized in that: The depth of the dispersed phase flow channel is greater than the depth of the emulsified flow channel; Preferably, the dispersed phase flow channel and the continuous phase flow channel have the same depth.

3. The microfluidic chip according to claim 1, characterized in that: The first carrier plate has a first through hole and a second through hole penetrating the first carrier plate, the first through hole constituting the first inlet, and the second through hole constituting the second inlet; The first carrier plate further has a third through hole penetrating the first carrier plate, and the third through hole constitutes the outlet; or the second carrier plate has a fourth through hole penetrating the second carrier plate, and the fourth through hole constitutes the outlet.

4. The microfluidic chip according to claim 1, characterized in that: The continuous phase flow channel comprises a continuous phase transmission flow channel and a droplet transmission flow channel which are interconnected; the continuous phase transmission flow channel is connected to the second inlet; One end of the emulsification channel away from the dispersed phase channel is connected to the side wall of the droplet transport channel, and the intersection of the emulsification channel and the droplet transport channel forms the stepped structure; the droplet transport channel is connected to the outlet.

5. The microfluidic chip according to claim 4, characterized in that: In a direction perpendicular to the extension direction of the continuous phase flow channel, the cross-sectional area of ​​the continuous phase transport flow channel is larger than the cross-sectional area of ​​the droplet transport flow channel.

6. The microfluidic chip according to claim 1, characterized in that: It comprises a plurality of emulsification channels arranged in sequence; the dispersed phase channel comprises a main transmission channel and a distribution channel which are interconnected, the end of the main transmission channel which is away from the distribution channel is connected to the first inlet, and the end of the emulsification channel which is away from the continuous phase channel is connected to the side wall of the distribution channel.

7. The microfluidic chip according to claim 6, characterized in that: The multiple emulsification channels have the same size.

8. The microfluidic chip according to claim 6 or 7, characterized in that: Along the extension direction of the distribution channel, the distribution channel has a middle position, and the main transmission channel is connected to the middle position to divide the distribution channel into two branches.

9. The microfluidic chip according to claim 8, characterized in that: The two branches are respectively a first branch and a second branch. In a direction perpendicular to the extension of the dispersed phase flow channel, a cross-sectional area of ​​the main transmission flow channel is greater than or equal to the sum of the cross-sectional areas of the first branch and the second branch.

10. The microfluidic chip according to claim 1, characterized in that: The depth difference between the continuous phase flow channel and the emulsification flow channel is 15 μm to 1000 μm; Preferably, the depth of the continuous phase flow channel is 20 μm to 1050 μm, and the depth of the emulsification flow channel is 5 μm to 50 μm.

Images