CN221108304U - Microfluidic chip and microfluidic chip system - Google Patents

Abstract

The application provides a microfluidic chip and a microfluidic chip system. The microfluidic chip comprises a continuous phase inlet, a continuous phase introduction channel communicated with the continuous phase inlet, a disperse phase introduction channel communicated with the disperse phase inlet, and a confluence channel. The microfluidic chip further comprises a continuous phase buffer channel and a continuous phase lead-out channel, wherein the continuous phase lead-in channel, the continuous phase buffer channel and the continuous phase lead-out channel are sequentially communicated, the continuous phase buffer channel comprises a plurality of curved flow channels which are connected with each other, the width of the continuous phase lead-out channel is smaller than that of the continuous phase lead-in channel, and one end of the converging channel is communicated with the continuous phase lead-out channel and the disperse phase lead-in channel. The application can effectively wrap single cell/single particle liquid drops under the condition of reducing the dosage of a continuous phase.

Description

Microfluidic chip and microfluidic chip system

Technical Field

The application relates to the field of single-cell sorting, in particular to a microfluidic chip and a microfluidic chip system with the microfluidic chip.

Background

Single cell sorting is a technology which is gradually rising in recent years, and can effectively increase the efficiency of biochemical reaction by limiting cells in single liquid drops, so that the method has important application prospects in single cell sequencing, antibody synthesis and targeted drug design.

In the related art, droplet microfluidic (droplet microfluidic) technology is often used for single cell sorting. Droplet microfluidic is a technology for manipulating small volumes of liquid based on microfluidic chip technology in recent years. In droplet microfluidics, droplets are formed by dispersing two mutually-immiscible liquids, one of which is a continuous phase and the other of which is a dispersed phase, in which the dispersed phase is divided into droplets of a minute volume under the action of shearing force, interfacial tension, viscous force, etc., of the fluid, and the droplets are dispersed in the continuous phase, to form an emulsion containing the droplets.

However, the continuous phase used to generate the microdroplets is typically an oily liquid of fluorosurfactant, which is relatively expensive and adds to the cost of preparing the microdroplet to some extent.

Disclosure of utility model

In view of this, it is necessary to provide a microfluidic chip capable of performing efficient single cell/single particle droplet encapsulation with reduced continuous phase usage.

In addition, it is also necessary to provide a microfluidic chip system having the microfluidic chip.

The first aspect of the application provides a microfluidic chip comprising a continuous phase inlet, a continuous phase introduction channel in communication with the continuous phase inlet, a dispersed phase introduction channel in communication with the dispersed phase inlet, and a confluence channel. The microfluidic chip further comprises a continuous phase buffer channel and a continuous phase lead-out channel, wherein the continuous phase lead-in channel, the continuous phase buffer channel and the continuous phase lead-out channel are sequentially communicated, the continuous phase buffer channel comprises a plurality of curved flow channels which are connected with each other, the width of the continuous phase lead-out channel is smaller than that of the continuous phase lead-in channel, and one end of the converging channel is communicated with the continuous phase lead-out channel and the disperse phase lead-in channel.

Based on the first aspect, in some possible implementations, the microfluidic chip further includes a disperse phase buffer channel and a disperse phase extraction channel, the disperse phase buffer channel, and the disperse phase extraction channel are sequentially communicated, the disperse phase buffer channel includes a plurality of curved runners connected to each other, a width of the disperse phase extraction channel is smaller than a width of the disperse phase extraction channel, the continuous phase extraction channel and the disperse phase extraction channel are communicated at a junction, and one end of the converging channel is connected to the junction.

Based on the first aspect, in some possible implementations, the width of the continuous phase extraction channel is 20 μm to 50 μm, the width of the disperse phase extraction channel is 20 μm to 50 μm, and the width of the converging channel connecting one end of the junction is 20 μm to 50 μm.

Based on the first aspect, in some possible implementations, the width of the continuous phase extraction channel is 30 μm, the width of the disperse phase extraction channel is 30 μm, and the width of the junction connecting one end of the junction is 30 μm.

Based on the first aspect, in some possible implementations, a width of an end of the converging channel connected to the junction is smaller than a width of the other end of the converging channel.

Based on the first aspect, in some possible implementations, the continuous phase inlet channel includes a first section and two second sections, one end of the first section is communicated with the continuous phase inlet, the two second sections are both connected to the other end of the first section, which is away from the continuous phase inlet, the number of the continuous phase buffer channels is two, the two second sections are respectively connected to the two continuous phase buffer channels, and the two second sections are disposed around the dispersed phase inlet, the dispersed phase inlet channel, the dispersed phase buffer channels, and the dispersed phase outlet channel.

Based on the first aspect, in some possible implementations, the continuous phase inlet channel and the converging channel are distributed on a straight line, and the number of the disperse phase inlet, the number of the disperse phase inlet channel, the number of the disperse phase buffer channel and the number of the disperse phase outlet channels are two, and are symmetrically distributed on two sides of the straight line.

Based on the first aspect, in some possible implementations, one of the disperse phase introduction channels is a streptavidin-modified microsphere channel and the other of the disperse phase introduction channels is a fluorescent antibody channel.

Based on the first aspect, in some possible implementations, the microfluidic chip further includes a first filter disposed between the continuous phase inlet and the continuous phase introduction channel.

Based on the first aspect, in some possible implementations, the microfluidic chip further includes a second filter disposed between the dispersed phase inlet and the dispersed phase introduction channel.

The second aspect of the application also provides a microfluidic chip system comprising a power device and a microfluidic chip as described above, wherein the power device is used for independently controlling the continuous phase and the disperse phase to be respectively injected into the continuous phase inlet and the disperse phase inlet.

In some possible implementations, the power device includes a plurality of independent injection members, the injection members are respectively connected to the continuous phase inlet and the disperse phase inlet, and the injection members have a receiving space for receiving the continuous phase or the disperse phase.

Based on the second aspect, in some possible implementation manners, the injection member includes a main body portion and an operation portion, the main body portion is provided with the accommodating space, the operation portion is at least partially disposed in the accommodating space, and the power device further includes a plurality of power members, each of which is connected to one of the operation portions.

In the application, the continuous phase enters the continuous phase inlet channel from the continuous phase inlet and then flows through the continuous phase buffer channel, and the continuous phase buffer channel can stabilize the flow velocity of the continuous phase, so that the flow velocity of the continuous phase entering the continuous phase outlet channel is stable. Moreover, the width of the continuous phase outlet channel is smaller than that of the continuous phase inlet channel, so that the dosage of the continuous phase can be reduced to a certain extent, and the single cell/single particle efficient package can be realized on the premise of reducing the preparation cost of the liquid drops.

Drawings

Fig. 1 is a schematic structural diagram of a microfluidic chip system according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of a microfluidic chip of the microfluidic chip system shown in fig. 1.

Fig. 3 is a micrograph of the droplet prepared in example 1 in bright field mode.

FIG. 4 is a micrograph of the droplet prepared in example 1 in fluorescence mode.

Description of the main reference signs

Microfluidic chip system 1

Microfluidic chip 10

Base layer 10a

Channel layer 10b

First surface 10b1

Second surface 10b2

Side 10b3

Continuous phase inlet 11

Dispersed phase inlet 12

Continuous phase introduction passage 13

Continuous phase buffer channel 14

Disperse phase introduction passage 15

Dispersed phase buffer channel 16

Continuous phase take-off channel 17

Disperse phase extraction channel 18

Confluence channel 19

Connecting device 20

Power plant 30

Injection member 31

Power element 32

First filter element 40

Second filter element 41

First segment 131

Second section 132

Body portion 311

An operation part 312

Opening 3110

Intersection P

Collecting port Q

Accommodation space S

The application will be further described in the following detailed description in conjunction with the above-described figures.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments.

It should be noted that when one component is considered to be "disposed on" another component, it may be disposed directly on the other component or there may be an intervening component present at the same time; when an element is referred to as being "mounted to" another element, it can be directly mounted to the other element or intervening elements may also be present. The term "and/or" as used herein includes all and any combination of one or more of the associated listed items.

Referring to fig. 1, an embodiment of the present application provides a microfluidic chip system 1, which includes a microfluidic chip 10, a connection device 20, a power device 30, and a collection device (not shown).

The microfluidic chip 10 is used to generate droplets. Referring to fig. 2, a continuous phase inlet 11 and a disperse phase inlet 12 are formed on the microfluidic chip 10, and a continuous phase inlet channel 13, a continuous phase buffer channel 14, a disperse phase inlet channel 15, a disperse phase buffer channel 16, a continuous phase outlet channel 17, a disperse phase outlet channel 18, and a converging channel 19 are formed inside the microfluidic chip 10. In some embodiments, the microfluidic chip 10 is provided with two disperse phase inlets 12, two disperse phase inlet channels 15, two disperse phase buffer channels 16, and two disperse phase outlet channels 18.

The continuous phase inlet 11 communicates with one end of the continuous phase introduction passage 13. The continuous phase introduction passage 13, the continuous phase buffer passage 14, and the continuous phase extraction passage 17 are sequentially communicated. Specifically, one end of the continuous phase buffer passage 14 communicates with the other end of the continuous phase introduction passage 13 facing away from the continuous phase inlet 11. One end of the continuous phase lead-out channel 17 communicates with the other end of the continuous phase buffer channel 14 facing away from the continuous phase lead-in channel 13. The continuous phase buffer channel 14 includes a plurality of interconnected tortuous flow passages (e.g., fig. 2 shows that the continuous phase buffer channel 14 includes a plurality of interconnected U-shaped flow passages to form a serpentine structure) for stabilizing the flow rate of the continuous phase after flowing through the continuous phase inlet channel 13 such that the flow rate of the continuous phase entering the continuous phase outlet channel 17 is stabilized. The width of the continuous phase outlet channel 17 is smaller than the width of the continuous phase inlet channel 13, so that the amount of continuous phase used can be reduced to some extent. In some embodiments, the width of the continuous phase extraction channel 17 is 20 μm to 50 μm, preferably the width of the continuous phase extraction channel 17 is 30 μm. By setting the width of the continuous phase extraction channel 17, it is advantageous to achieve efficient encapsulation of single cells/single particles while reducing the amount of continuous phase used.

Each of the dispersed phase inlets 12 communicates with one end of one of the dispersed phase introduction passages 15. The dispersed phase introduction passage 15, the dispersed phase buffer passage 16, and the dispersed phase extraction passage 18 are communicated in this order. Specifically, one end of each dispersed phase buffer channel 16 communicates with the other end of a dispersed phase introduction channel 15 facing away from the dispersed phase inlet 12. One end of each disperse phase lead-out channel 18 is communicated with the other end of a disperse phase buffer channel 16 which is away from the disperse phase lead-in channel 15. The dispersed phase buffer channel 16 includes a plurality of interconnected curved flow channels (e.g., fig. 2 shows that the dispersed phase buffer channel 16 includes a plurality of interconnected U-shaped flow channels to form a serpentine structure) for stabilizing the flow rate of the dispersed phase after flowing through the dispersed phase inlet channel 15, so that the flow rate of the dispersed phase entering the dispersed phase outlet channel 18 is stabilized. The width of the dispersed phase extraction channel 18 is smaller than the width of the dispersed phase introduction channel 15, so that the amount of the dispersed phase can be reduced to some extent. In some embodiments, the width of the dispersed phase extraction channel 18 is 20 μm to 50 μm, preferably the width of the dispersed phase extraction channel 18 is 30 μm. By setting the width of the dispersed phase extraction channel 18, efficient preparation of droplets is facilitated while the amount of dispersed phase used is reduced.

The disperse phase extraction channels 18 are in communication with the continuous phase extraction channels 17 at the junction P. One end of the converging channel 19 is connected to the junction P, and the other end of the converging channel 19 facing away from the junction P is a collecting port Q, which is communicated with the collecting device. In some embodiments, the width of the junction channel 19 at the end where the junction P is connected is 20 μm to 50 μm, and preferably the width of the junction channel 19 at the end where the junction P is connected is 30 μm. The width of the converging channel 19 at one end of the junction P is smaller than the width of the other end at the collection port Q, and in this embodiment, the width of the converging channel 19 at the other end at the collection port Q is 100 μm. By providing the converging passage 19 with an increased width at one end at the collection port Q, it is advantageous to increase the generation flux of droplets and reduce the occurrence of clogging. The continuous phase may be an oil phase or the like, and the dispersed phase may be a cell fluid, a bead fluid, water or the like.

In the present application, the continuous phase enters the continuous phase inlet channel 13 from the continuous phase inlet 11 and then flows through the continuous phase buffer channel 14, and the continuous phase buffer channel 14 can stabilize the flow rate of the continuous phase, so that the continuous phase flow entering the continuous phase outlet channel 17 is stable. The disperse phase enters the corresponding disperse phase inlet channel 15 from each disperse phase inlet 12 and flows through the corresponding disperse phase buffer channel 16, and the disperse phase buffer channel 16 can stabilize the flow velocity of the disperse phase, so that the flow velocity of the disperse phase entering the disperse phase outlet channel 18 is stable. The continuous phase and the disperse phase are converged at the junction P, and under the action of shearing force, the continuous phase breaks the disperse phase into a discontinuous state to obtain liquid drops, and the flow rates of the disperse phase and the continuous phase are stable, so that the liquid drops with uniform sizes are generated. Moreover, since the width of the continuous phase extraction channel 17 is smaller than that of the continuous phase introduction channel 13, the amount of continuous phase used can be reduced to some extent, thereby realizing efficient encapsulation of single cells/single particles with reduced production costs of droplets.

In some embodiments, the microfluidic chip 10 includes a base layer 10a and a channel layer 10b that are stacked. The channel layer 10b comprises a first surface 10b1 facing the substrate layer 10a, a second surface 10b2 arranged away from the first surface 10b1, and a side surface 10b3 connected between the first surface 10b1 and the second surface 10b 2. The continuous phase inlet 11 and the two disperse phase inlets 12 may be disposed on the second surface 10b2, respectively, and may be formed by recessing the second surface 10b2 toward the first surface 10b 1. The continuous phase inlet 11 and the two disperse phase inlets 12 may also be provided on the side 10b3.

In some embodiments, the continuous phase introduction channel 13 includes a first segment 131 and two second segments 132. One end of the first section 131 of the continuous phase introduction passage 13 communicates with the continuous phase inlet 11. Two second sections 132 are connected to the other end of the first section 131 facing away from the continuous phase inlet 11, and the widths of the two second sections 132 may be the same. Thus, after entering the first segment 131 of the continuous phase introduction channel 13 from the continuous phase inlet 11, the continuous phase is uniformly split into two symmetrical paths, which respectively enter the two second segments 132. Correspondingly, the number of continuous phase buffer channels 14 is two, and the two continuous phase buffer channels 14 are in one-to-one communication with the two second segments 132. Wherein the first segment 131 of the continuous phase introduction channel 13 may be linear and each second segment 132 may be arcuate. Each of the dispersed phase introduction passages 15 may be linear.

Further, in some embodiments, the continuous phase introduction channels 13 and the converging channels 19 are disposed on a straight line, the two disperse phase inlets 12 are symmetrically disposed on two sides of the straight line, the two disperse phase introduction channels 15 are symmetrically disposed on two sides of the straight line, and the two disperse phase buffer channels 16 are also symmetrically disposed on two sides of the straight line. The two second sections 132 are symmetrically disposed on both sides of the straight line and are disposed around the two dispersed phase inlets 12 and the two dispersed phase introducing passages 15.

In some embodiments, a first filter 40 is disposed between the continuous phase inlet 11 and the continuous phase introduction channel 13, and a second filter 41 is disposed between the dispersed phase inlet 12 and the dispersed phase introduction channel 15. The first filter 40 and the second filter 41 are used to prevent cell clusters or particle clusters from passing through, to improve the packing rate of single cells or single particles, and to prevent the microfluidic chip 10 from being blocked by external impurities. Wherein the first filter 40 and the second filter 41 may be filter columns.

The connection device 20 is used for connecting the microfluidic chip 10 and the power device 30. In some embodiments, the connection device 20 may be a capillary hose. One end of the capillary hose is connected with the continuous phase inlet 11 or the disperse phase inlet 12 of the microfluidic chip 10, and the other end of the capillary hose is connected with the power device 30.

The power unit 30 is used to independently drive the continuous phase and the disperse phase to be injected into the continuous phase inlet 11 and the disperse phase inlet 12, respectively. The power device 30 is also used to provide the microfluidic chip 10 with motive power for generating droplets, so that the injected continuous phase flows in the continuous phase introduction channel 13, the continuous phase buffer channel 14, and the continuous phase extraction channel 17, and the injected dispersed phase flows in the dispersed phase introduction channel 15, the dispersed phase buffer channel 16, and the dispersed phase extraction channel 18, and then merges in the confluence channel 19 to form droplets. In some embodiments, the power device 30 is a positive pressure generating device, and in particular, the power device 30 may include a plurality of injection members 31 (such as injectors) independent of each other, where the plurality of injection members 31 are respectively connected to the continuous phase inlet 11 and the two disperse phase inlets 12 (for simplicity, fig. 1 only shows one injection member 31 connected to the continuous phase inlet 11). Each injection piece 31 includes a main body portion 311 and an operation portion 312. The main body 311 is used for accommodating a continuous phase or a disperse phase. The main body 311 has a hollow structure and a space S in which the continuous phase or the dispersion phase is compatible. The body 311 further has an opening 3110 communicating with the accommodation space S, and the connector 20 is connected to the opening 3110. The operation portion 312 is at least partially accommodated in the accommodating space S and is tightly adhered to the inner wall of the accommodating space S, and the operation portion 312 may be a piston. When the operation portion 312 is subjected to an external force, it slides in the accommodation space S, and the internal pressure of the main body portion 311 increases, so that the continuous phase and the dispersed phase in the main body portion 311 are injected into the continuous phase inlet 11 and the continuous phase inlet 11, respectively. The pressure may also cause the injected continuous and dispersed phases to flow within the corresponding channels, respectively.

Further, in some embodiments, the power device 30 may further include a power member 32 connected to the operation portion 312, where the power member 32 is configured to push the operation portion 312 to move. The power element 32 may be a syringe pump, and the operation portion 312 of the injection element 31 is pushed by the syringe pump to move, so that the thrust force can be precisely controlled.

The collection device is used to collect droplets flowing from the microfluidic chip 10. In some embodiments, the collection device may be any container suitable for collecting droplets.

The present application will be described in detail with reference to the following examples.

Example 1

(1) Microfluidic chip 10 preparation: the substrate layer 10a is made of glass, and more specifically, the substrate layer 10a may be a glass slide, with dimensions of 75mm×22mm, and a thickness of 1.1mm. The material of the channel layer 10b is Polydimethylsiloxane (PDMS), the manufacturing process of the channel layer 10b is to obtain a template through a photoetching method, the template is subjected to template turning by using the PDMS, the thickness of the template turning is 6mm, and thus the channel layer 10b with a channel structure is obtained, wherein the continuous phase buffer channel 14 and the disperse phase buffer channel 16 respectively comprise five U-shaped channels which are sequentially connected, the width of the continuous phase leading-out channel 17 is 30 mu m, the width of the disperse phase leading-out channel 18 is 30 mu m, and the width of one end of the converging channel 19 at the junction P is 30 mu m; the surface treatment is carried out on the basal layer 10a and the channel layer 10b respectively through plasma, a plasma cleaning instrument (model Diener ATTO-BRS) can be adopted for the plasma treatment, and then the basal layer 10a and the channel layer 10b are attached, so that the basal layer 10a and the channel layer 10b are bonded after being attached, and the microfluidic chip 10 is obtained; and placing the bonded microfluidic chip 10 in a vacuum drying oven for post-baking overnight, enhancing the bonding effect and enabling the microfluidic chip 10 to recover the hydrophobicity. To ensure the hydrophobicity of the channels inside the microfluidic chip 10, the microfluidic chip 10 is hydrophobically modified by using a glass hydrophobicizing agent (Aquapel GLASS TREATMENT) before droplet generation, specifically, a modifying agent is injected into the channels by a syringe to fill the channels of the whole microfluidic chip 10 for 1 minute, and then the channels are washed by using a fluorinated liquid (model number HFE-7500) to discharge the modifying agent in the channels.

(2) Preparing a first disperse phase: taking a proper amount of streptavidin modified polystyrene microsphere suspension (STREPTAVIDIN POLYSTYRENE PARTICLES with the diameter of 6.69 mu m and manufactured by Spheretech), and diluting to the mass concentration of 0.1%; mixing the polystyrene microsphere suspension with the biotinylated antibody in PBS (phosphate buffer solution) at room temperature, and placing the mixed solution on a test tube mixer for rotating for 1 hour at 40rpm; the microspheres were separated from the mixed solution by centrifugation at 7000rpm for 2min, and dispersed with an equal volume of the heavy suspension to produce a first dispersed phase.

(3) Preparing a second disperse phase: to the suspension without microspheres, an appropriate amount of fluorescent antibody (Goat anti-Rabbit IgG (H+L), alexa Fluor 532) was added and mixed thoroughly to obtain a second dispersed phase.

(4) And (3) liquid drop preparation: the first disperse phase and the second disperse phase are respectively transferred into two injection pieces 31 (model Pico Plus Elite, manufacturer Harvard Apparatus), the two injection pieces 31 are fixed on a power piece 32 and are respectively connected to two disperse phase inlets 12 on the microfluidic chip 10 through capillary hoses; a proper amount of droplet-generating oil was taken and placed in another injection member 31, which was connected to the continuous phase inlet 11 on the microfluidic chip 10 using the same operation; by operating the power member 32, two dispersed phase flow rates of 200. Mu.L/h each, and a continuous phase flow rate of 300. Mu.L/h were set, and the continuous phase and the dispersed phase were joined in the confluence passage 19 to form droplets.

Fig. 3 and 4 are schematic views of the droplets produced in example 1. Wherein, the polystyrene microsphere is combined by biotin-streptavidin, and then the surface modification is carried out by a fluorescent antibody with a labeling function, and the biotin is connected with the fluorescent antibody with a fluorescent group. Fluorescent enrichment is achieved by attaching fluorescent antibodies with fluorescent groups to the surface of polystyrene microspheres through interaction between biotin-streptavidin, thereby amplifying fluorescent signals. As can be seen from FIGS. 3 and 4, the microfluidic chip system 1 provided by the application can be used for efficiently wrapping fluorescent particles in an oil phase, the continuous phase flow rate and the disperse phase flow rate are controlled by arranging the power device 10 and the buffer channel, and the final prepared liquid drop volume is about 35pL by combining the width design of the channel, the oil-water flux ratio is 3:4 (less than 1), the occurrence frequency of the liquid drop is about 3.3kHz, and the liquid drop wrapped by single particles accounts for 20%.

The present application is not limited to the above-mentioned embodiments, but is capable of other and obvious modifications and equivalents of the above-mentioned embodiments, which will be apparent to those skilled in the art from consideration of the present application without departing from the scope of the present application.

Claims (13)

1. A microfluidic chip comprising a continuous phase inlet, a continuous phase introduction channel communicated with the continuous phase inlet, a disperse phase introduction channel communicated with the disperse phase inlet, and a confluence channel, is characterized in that,

The microfluidic chip further comprises a continuous phase buffer channel and a continuous phase lead-out channel, wherein the continuous phase lead-in channel, the continuous phase buffer channel and the continuous phase lead-out channel are sequentially communicated, the continuous phase buffer channel comprises a plurality of bent flow channels which are sequentially connected end to end, the width of the continuous phase lead-out channel is smaller than that of the continuous phase lead-in channel, and one end of the converging channel is communicated with the continuous phase lead-out channel and the disperse phase lead-in channel.

2. The microfluidic chip of claim 1, further comprising a disperse phase buffer channel and a disperse phase extraction channel, wherein the disperse phase extraction channel, the disperse phase buffer channel and the disperse phase extraction channel are sequentially communicated, the disperse phase buffer channel comprises a plurality of sequentially connected curved flow channels, the width of the disperse phase extraction channel is smaller than the width of the disperse phase extraction channel, the continuous phase extraction channel and the disperse phase extraction channel are communicated at a junction, and one end of the converging channel is connected to the junction.

3. The microfluidic chip according to claim 2, wherein the width of the continuous phase extraction channel is 20 μm to 50 μm, the width of the disperse phase extraction channel is 20 μm to 50 μm, and the width of the junction channel at one end connected to the junction is 20 μm to 50 μm.

4. The microfluidic chip according to claim 3, wherein the width of the continuous phase extraction channel is 30 μm, the width of the disperse phase extraction channel is 30 μm, and the width of the junction channel at the end connected to the junction is 30 μm.

5. The microfluidic chip of claim 2, wherein a width of an end of the confluence channel connecting the junction is smaller than a width of the other end of the confluence channel.

6. The microfluidic chip according to claim 2, wherein the continuous phase inlet channel comprises a first section and two second sections, one end of the first section is communicated with the continuous phase inlet, the two second sections are connected to the other end of the first section away from the continuous phase inlet, the number of the continuous phase buffer channels is two, the two second sections are respectively connected to the two continuous phase buffer channels, and the two second sections are arranged around the dispersed phase inlet, the dispersed phase inlet channel, the dispersed phase buffer channels and the dispersed phase outlet channel.

7. The microfluidic chip according to claim 6, wherein the continuous phase inlet channel and the confluence channel are distributed on a straight line, and the number of the disperse phase inlet, the number of the disperse phase inlet channel, the number of the disperse phase buffer channel and the number of the disperse phase outlet channels are two, and are symmetrically distributed on two sides of the straight line.

8. The microfluidic chip according to claim 7, wherein one of said discrete phase introduction channels is a streptavidin-modified microsphere channel and the other of said discrete phase introduction channels is a fluorescent antibody channel.

9. The microfluidic chip of claim 1, further comprising a first filter disposed between the continuous phase inlet and the continuous phase introduction channel.

10. The microfluidic chip of claim 1, further comprising a second filter disposed between the disperse phase inlet and the disperse phase introduction channel.

11. A microfluidic chip system comprising a power device for independently controlling injection of a continuous phase and a disperse phase into the continuous phase inlet and the disperse phase inlet, respectively, and a microfluidic chip as claimed in any one of claims 1 to 10.

12. The microfluidic chip system according to claim 11, wherein the power device comprises a plurality of injection members independent of each other, the plurality of injection members being connected to the continuous phase inlet and the disperse phase inlet, respectively, the injection members having receiving spaces for receiving the continuous phase or the disperse phase.

13. The microfluidic chip system according to claim 12, wherein the injection member comprises a main body portion and an operation portion, the main body portion is provided with the accommodating space, the operation portion is at least partially disposed in the accommodating space, and the power device further comprises a plurality of power members, each of the power members is connected to one of the operation portions.