阅读说明：本技术 一种微流控装置及其制造方法和提取方法 (Microfluidic device and manufacturing method and extraction method thereof ) 是由 白云飞 席克瑞 贾振宇 林柏全 秦锋 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种微流控装置及其制造方法和提取方法,该微流控装置包括：至少一级流道结构；流道结构包括流道部和陷阱部,流道部包括第一流道、第二流道和第三流道,第二流道的第一端和第三流道的第一端均连通至第一流道的第二端,第二流道的宽度小于第三流道的宽度；陷阱部包括陷阱,陷阱位于第二流道的第二端,在同方向上,第二流道的宽度小于或等于陷阱的宽度,在垂直于流道结构所在平面的方向上,陷阱的深度大于第二流道的深度。本发明中,第二流道从样品中分离出了最大尺寸小于第二流道宽度的微珠,实现样品中的微珠分离；第二流道分离出的微珠在陷阱处被获取。该微流控装置成本低廉、操作步骤简单、提取高效且无污染。(The invention discloses a microfluidic device and a manufacturing method and an extraction method thereof, wherein the microfluidic device comprises: at least one stage of flow channel structure; the flow channel structure comprises a flow channel part and a trap part, the flow channel part comprises a first flow channel, a second flow channel and a third flow channel, a first end of the second flow channel and a first end of the third flow channel are communicated to a second end of the first flow channel, and the width of the second flow channel is smaller than that of the third flow channel; the trap part comprises a trap, the trap is positioned at the second end of the second flow channel, the width of the second flow channel is smaller than or equal to the width of the trap in the same direction, and the depth of the trap is larger than that of the second flow channel in the direction perpendicular to the plane of the flow channel structure. In the invention, the second flow channel separates the microbeads of which the maximum size is smaller than the width of the second flow channel from the sample, so that the separation of the microbeads in the sample is realized; the microbeads separated by the second flow path are captured at the trap. The microfluidic device has the advantages of low cost, simple operation steps, high extraction efficiency and no pollution.)

1. A microfluidic device, comprising: at least one stage of flow channel structure;

the flow channel structure comprises a flow channel part and a trap part, the flow channel part comprises a first flow channel, a second flow channel and a third flow channel, each flow channel is provided with a first end and a second end, the first end of the second flow channel and the first end of the third flow channel are communicated to the second end of the first flow channel, the width of the second flow channel is smaller than that of the third flow channel, and the width of the flow channel is the size of the flow channel in the direction perpendicular to the extending direction of the flow channel in the plane of the flow channel structure;

the trap part comprises a trap, the trap is positioned at the second end of the second flow channel, the width of the second flow channel is smaller than or equal to the width of the trap in the same direction, and the depth of the trap is larger than that of the second flow channel in the direction perpendicular to the plane of the flow channel structure.

2. The microfluidic device according to claim 1, wherein the microfluidic device comprises a multi-stage cascaded flow channel structure, and the third flow channel of an upper stage flow channel structure is multiplexed as the first flow channel of a lower stage flow channel structure.

3. The microfluidic device according to claim 1, wherein the first flow channel extends in the same direction as the second flow channel, and a connecting line of the first end and the second end of the third flow channel intersects with the extending direction of the first flow channel.

4. The microfluidic device according to claim 3, wherein the third flow channel includes a bent portion and a straight portion, an extending direction of the bent portion intersects an extending direction of the straight portion, the bent portion includes a first end and a second end, the second end is communicated with the straight portion, and the first end is communicated with the second end of the first flow channel.

5. The microfluidic device according to claim 4, wherein the microfluidic device comprises a multi-stage cascaded flow channel structure, and the straight part of the third flow channel of the upper stage flow channel structure is multiplexed as the first flow channel of the lower stage flow channel structure.

6. The microfluidic device according to claim 4, wherein the straight portion of the third flow channel extends in the same direction as the first flow channel.

7. The microfluidic device according to claim 1, wherein the microfluidic device comprises a multi-stage cascade of flow channel structures, at least two adjacent stages of flow channel structures exist in the multi-stage cascade of flow channel structures, and the widths of the second flow channels are the same; and/or the presence of a gas in the gas,

in the multi-stage cascade flow channel structure, at least two adjacent stages of flow channel structures exist, and the widths of the second flow channels are different.

8. The microfluidic device according to claim 1, wherein the trap section includes a trap channel communicating with the trap in a direction parallel to a plane of the channel structure, the trap channel has a depth equal to a depth of the trap, and a width greater than or equal to a width of the second channel.

9. The microfluidic device according to claim 8, wherein the channel portion comprises at least two of the second channels, and the trap channels of the trap portion sequentially penetrate each of the traps in a direction parallel to a plane in which the channel structure is located.

10. The microfluidic device according to claim 8, wherein the microfluidic device comprises a multi-stage cascade of flow channel structures, at least two adjacent stages of flow channel structures exist in the multi-stage cascade of flow channel structures, and the widths of the second flow channels are the same;

the trap flow channel of the adjacent two-stage flow channel structure is communicated with the first end, and/or the trap flow channel of the adjacent two-stage flow channel structure is communicated with the second end.

11. The microfluidic device according to claim 1, wherein the microfluidic device comprises a first substrate and a second substrate bonded to the first substrate, the at least one primary flow channel structure being disposed on a surface of the first substrate facing the second substrate.

12. The microfluidic device according to claim 1, wherein the microfluidic device comprises a first substrate and a second substrate bonded to the first substrate;

in the flow path structure, the flow path portion is provided on a surface of the second substrate facing the first substrate, and the trap portion is provided on a surface of the first substrate facing the second substrate.

13. The microfluidic device according to claim 11 or 12, wherein a spacing between the bonding interface of the two substrates and a surface of the first substrate facing away from the second substrate is gradually decreased in a direction in which the first end of the flow channel points towards the second end.

14. The microfluidic device according to claim 11 or 12, wherein the microfluidic device comprises a first stage flow channel structure and a last stage flow channel structure, wherein a first end of a first flow channel of the first stage flow channel structure extends to a side of the microfluidic device, and a second end of a third flow channel of the last stage flow channel structure extends to a side of the microfluidic device.

15. The microfluidic device according to claim 11 or 12, wherein the microfluidic device has a liquid injection hole, the microfluidic device comprises a first-stage flow channel structure and a last-stage flow channel structure, and the liquid injection hole penetrates through the first substrate or the second substrate until a first end of a first flow channel of the first-stage flow channel structure is exposed;

the micro-fluidic device is provided with a liquid outlet hole which penetrates through the first substrate or the second substrate until the second end of the third flow channel of the final-stage flow channel structure is exposed.

16. The microfluidic device according to claim 11 or 12, wherein the trap section comprises a trap channel that penetrates the trap in a direction parallel to a bonding interface of two substrates;

the micro-fluidic device is provided with an air inlet hole and an air outlet hole, the air inlet hole penetrates through the first substrate or the second substrate until the first end of the trap flow channel is exposed, and the air outlet hole penetrates through the first substrate or the second substrate until the second end of the trap flow channel is exposed.

17. A method of manufacturing a microfluidic device, comprising:

providing a first substrate and a second substrate;

performing first etching on the first substrate to form a trap part;

performing first etching on the second substrate to form a runner part, or exposing the trap part and performing second etching on the first substrate to form the runner part; the flow channel part comprises a first flow channel, a second flow channel and a third flow channel, each flow channel is provided with a first end and a second end, the first end of the second flow channel and the first end of the third flow channel are communicated to the second end of the first flow channel, the width of the second flow channel is smaller than that of the third flow channel, and the width of the flow channel is the size of the flow channel in the direction perpendicular to the extending direction of the flow channel in the plane of the flow channel structure; the trap part comprises a trap, the trap is positioned at the second end of the second flow channel, the width of the second flow channel is less than or equal to the width of the trap in the same direction, and the depth of the trap in the direction perpendicular to the plane of the flow channel structure is greater than the depth of the second flow channel;

and bonding the first substrate and the second substrate to align the trap part and the flow channel part to form a flow channel structure.

18. A method of extracting a microfluidic device according to any one of claims 1 to 17, wherein the trap section further comprises a trap channel communicating with the trap in a direction parallel to the plane of the channel structure;

the extraction method comprises the following steps:

injecting a sample to be detected into the first flow channel in a liquid injection stage, so that microbeads to be extracted in the sample to be detected enter the trap through the second flow channel;

and in the extraction stage, filling inert gas into the first end of the trap flow channel, and discharging the microbeads in the trap through the second end of the trap flow channel.

19. The extraction method according to claim 18, further comprising: and a cleaning stage, injecting inert gas into the second end of the third flow channel, and discharging the sample remained in the flow channel part through the first end of the first flow channel.

Technical Field

The invention relates to the technical field of microfluidics, in particular to a microfluidic device and a manufacturing method and an extraction method thereof.

Background

In the fields of biology and chemistry, laboratories or actual working environments, it is often necessary to perform operations such as separation, preparation, chemical reactions, and detection on a sample to be tested, so as to facilitate subsequent testing and detection. For example, cells of different sizes are extracted from blood, molecules of different sizes are extracted from a fluid, and the extracted minute objects are called microbeads.

The existing bead extraction methods are many. For example, by chemical reaction, the desired beads are extracted by a plurality of steps such as displacement reaction, centrifugation, and precipitation. Alternatively, the desired beads are extracted from the sample with the aid of microscopic observation.

Obviously, the existing bead extraction method has the problems of low efficiency and pollution risk.

Disclosure of Invention

The embodiment of the invention provides a micro-fluidic device, a manufacturing method and an extraction method thereof, and aims to solve the problems of complicated and complicated micro-bead extraction steps, low efficiency, easy pollution and the like in the prior art.

An embodiment of the present invention provides a microfluidic device, including: at least one stage of flow channel structure;

the flow channel structure comprises a flow channel part and a trap part, the flow channel part comprises a first flow channel, a second flow channel and a third flow channel, each flow channel is provided with a first end and a second end, the first end of the second flow channel and the first end of the third flow channel are communicated to the second end of the first flow channel, the width of the second flow channel is smaller than that of the third flow channel, and the width of the flow channel is the size of the flow channel in the direction perpendicular to the extending direction of the flow channel in the plane of the flow channel structure;

the trap part comprises a trap, the trap is positioned at the second end of the second flow channel, the width of the second flow channel is smaller than or equal to the width of the trap in the same direction, and the depth of the trap is larger than that of the second flow channel in the direction perpendicular to the plane of the flow channel structure.

Based on the same inventive concept, the embodiment of the invention also provides a manufacturing method of the microfluidic device, which comprises the following steps:

providing a first substrate and a second substrate;

performing first etching on the first substrate to form a trap part;

performing first etching on the second substrate to form a runner part, or exposing the trap part and performing second etching on the first substrate to form the runner part; the flow channel part comprises a first flow channel, a second flow channel and a third flow channel, each flow channel is provided with a first end and a second end, the first end of the second flow channel and the first end of the third flow channel are communicated to the second end of the first flow channel, the width of the second flow channel is smaller than that of the third flow channel, and the width of the flow channel is the size of the flow channel in the direction perpendicular to the extending direction of the flow channel in the plane of the flow channel structure; the trap part comprises a trap, the trap is positioned at the second end of the second flow channel, the width of the second flow channel is smaller than or equal to the width of the trap in the same direction, and the depth of the trap is larger than that of the second flow channel in the direction perpendicular to the plane of the flow channel structure;

and bonding the first substrate and the second substrate to align the trap part and the flow channel part to form a flow channel structure.

Based on the same inventive concept, the embodiment of the invention also provides an extraction method of the microfluidic device, the trap part further comprises a trap flow channel, and the trap flow channel is communicated with the trap in the direction parallel to the plane of the flow channel structure;

the extraction method comprises the following steps:

injecting a sample to be detected into the first flow channel in an injection stage, so that microbeads to be extracted in the sample to be detected enter the trap through the second flow channel;

and in the extraction stage, filling inert gas into the first end of the trap flow channel, and discharging the microbeads in the trap through the second end of the trap flow channel.

The microfluidic device provided by the embodiment of the invention has at least one stage of flow channel structure, and a sample containing microbeads enters a first flow channel of the flow channel structure and then flows to a second flow channel and a third flow channel through a driving force, wherein the maximum size of the microbeads entering the second flow channel is smaller than the width of the second flow channel, and the remaining samples enter the third flow channel, so that the microbeads with the maximum size smaller than the width of the second flow channel are separated from the sample by the second flow channel, and the separation of the microbeads in the sample is realized. The separated microbeads flow in the second flow channel and are obtained at the trap, the depth of the trap is greater than that of the second flow channel, so that the microbeads entering the trap are not easy to flow out, and the separated microbeads are captured through the gradient depth of the flow channel structure. According to the embodiment of the invention, the microfluidic device can realize the functions of separating and capturing the microbeads in the sample, and has the advantages of low cost, simple steps, high extraction efficiency and almost no pollution risk.

Drawings

To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description will be given below of the drawings required for the embodiments or the technical solutions in the prior art, and it is obvious that the drawings in the following description, although being some specific embodiments of the present invention, can be extended and extended to other structures and drawings by those skilled in the art according to the basic concepts of the device structure, the driving method and the manufacturing method disclosed and suggested by the various embodiments of the present invention, without making sure that these should be within the scope of the claims of the present invention.

Fig. 1 is a schematic view of a microfluidic device provided by an embodiment of the present invention;

FIG. 2 is a cross-sectional view taken along A-A' of FIG. 1;

FIG. 3 is a schematic view of a multi-stage flow channel configuration;

FIG. 4 is a schematic view of a second multi-stage flow channel configuration;

FIG. 5 is a schematic view of a flow channel configuration;

FIG. 6 is a schematic view of a second flow channel configuration;

FIG. 7 is a schematic view of a third multi-stage flow channel configuration;

FIG. 8 is a schematic view of a third flow channel configuration;

FIG. 9 is a schematic view of a fourth flow channel configuration;

FIG. 10 is a schematic view of a fifth flow channel configuration;

FIG. 11 is a schematic view of a fourth multi-stage flow channel configuration;

FIG. 12 is a schematic view of a microfluidic device;

FIG. 13 is a cross-sectional view taken along line B-B' of FIG. 12;

FIG. 14 is a second cross-sectional view taken along line B-B' of FIG. 12;

FIG. 15 is a third cross-sectional view taken along line B-B' of FIG. 12;

FIG. 16 is a fourth cross-sectional view taken along line B-B' of FIG. 12;

FIG. 17 is a schematic view of a fifth multi-stage flow channel configuration;

FIG. 18 is a schematic view of a sixth multi-stage flow channel configuration;

FIG. 19 is a schematic view of a seventh multi-stage flow channel configuration;

FIG. 20 is a schematic view of an eighth multi-stage flow channel configuration;

fig. 21 is a schematic view of a method of manufacturing a microfluidic device according to an embodiment of the present invention;

FIG. 22 is a schematic diagram of a microfluidic device fabrication configuration;

FIG. 23 is a schematic diagram of another microfluidic device fabrication configuration;

fig. 24 is a schematic diagram of an extraction method of a microfluidic device provided in an embodiment of the present invention;

fig. 25 is a schematic diagram of an injection phase of the microfluidic device;

fig. 26 is a schematic diagram of an extraction stage of the microfluidic device;

fig. 27 is a schematic view of another microfluidic device extraction method provided in an embodiment of the present invention;

fig. 28 is a schematic diagram of a cleaning stage of the microfluidic device.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described through embodiments with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the basic idea disclosed and suggested by the embodiments of the present invention, are within the scope of the present invention.

The embodiment of the invention provides a micro-fluidic device which is mainly used for separating micro-beads in samples in the processes of biological, chemical, medical, fluid and material analysis. It will be appreciated that the microfluidic device may also be used in other techniques of sample preparation, analysis, detection, etc., and will not be described in detail in embodiments of the present invention. It is understood that the samples contain microbeads of different sizes; alternatively, the sample is a fluid comprising a solution and microbeads in the solution. The separation specifically means that microbeads are separated and extracted from a sample.

As shown in fig. 1 and 2, fig. 1 is a schematic view of a microfluidic device according to an embodiment of the present invention, and fig. 2 is a cross-sectional view of fig. 1 taken along a-a', the microfluidic device according to an embodiment of the present invention includes: at least one stage of flow channel structure 1; the flow channel structure 1 comprises a flow channel part 10 and a trap part 20, the flow channel part 10 comprises a first flow channel 11a, a second flow channel 11b and a third flow channel 11c, each flow channel is provided with a first end and a second end, the first end of the second flow channel 11b and the first end of the third flow channel 11c are communicated to the second end of the first flow channel 11a, the width of the second flow channel 11b is smaller than that of the third flow channel 11c, and the width of the flow channel is the size of the flow channel in the direction perpendicular to the extending direction of the flow channel in the plane of the flow channel structure 1; the trap portion 20 includes a trap 21, the trap 21 is located at a second end of the second flow channel 11b, a width of the second flow channel 11b is smaller than or equal to a width of the trap 21 in the same direction, and a depth of the trap 21 is larger than a depth of the second flow channel 11b in a direction perpendicular to a plane in which the flow channel structure 1 is located.

In this embodiment, the microfluidic device includes one or more stages of flow channel structures 1, i.e., flow channel structures etched on a substrate surface, and fig. 1 shows only one stage of flow channel structure 1. The flow channel structure 1 is functionally divided, and different region structures of the flow channel structure 1 can be divided into a flow channel part 10 and a trap part 20, and it can be understood that the flow channel part 10 is a flow path of a sample containing microbeads, and the trap part 20 is used for acquiring the microbeads in the sample. The sample screened by the microfluidic device can only contain microbeads with different sizes, the sample can also contain solution and microbeads with different sizes, which are combined by different cells and labeled antibodies in the solution, and the sample screened by the microfluidic device can also contain cell dissolving solution, wherein the cell dissolving solution contains cells with different sizes.

Obviously, based on the functions of different area structures, the flow channel portion 10 includes a plurality of strip-shaped flow channels that are connected, where the strip-shaped flow channel is a flow channel that has a width much smaller than its length, and the strip-shaped flow channel may be a straight flow channel or a bent flow channel with a bend, and under the condition that the flow of a sample and the separation of microbeads in the sample are not affected, the shape of the flow channel is not particularly limited, and the selectable bent flow channel includes a plurality of straight branch portions, and a connection area where two adjacent straight branch portions exist is in bent connection. The trap portion 20 includes a plurality of traps 21, an opening of the trap 21 is close to a depth, or an opening of the trap 21 is smaller than the depth so as to trap the bead therein, and the trap 21 may be a cylinder, or any one of a cube, a cuboid, a hemisphere, and the like so as to limit the bead. The flow path portion 10 shown in fig. 1 includes a straight flow path and a bent flow path, and the trap 21 may be a cylinder.

In the present embodiment, the flow channel part 10 includes a first flow channel 11a, a second flow channel 11b and a third flow channel 11c, each having a first end and a second end, and it is understood that an inlet when a sample flows into the flow channel is the first end of the flow channel, and an outlet when the sample flows out of the flow channel is the second end of the flow channel. The first end of the second channel 11b and the first end of the third channel 11c are both connected to the second end of the first channel 11a, and it can be understood that the sample enters the first channel 11a, passes through the second end of the first channel 11a, enters the second channel 11b from the first end of the second channel 11b, and enters the third channel 11c from the first end of the third channel 11 c.

The width of the second flow channel 11b is smaller than that of the third flow channel 11c, and the width of the flow channel is the size of the flow channel in the direction perpendicular to the extending direction of the flow channel in the plane of the flow channel structure 1. The flow channel is provided with an axial lead, the direction along the axial lead of the flow channel is the axial direction of the flow channel, and the flow channel is also provided with a radial direction which is perpendicular to the axial direction of the flow channel. As shown in fig. 1, straight branch portions of the selectable first flow channel 11a, the second flow channel 11b and the third flow channel 11c have the same axial direction X, and also have the same first radial direction Y parallel to the plane of the flow channel structure on the plane of the flow channel structure, a dimension of the flow channel in the first radial direction Y is a width of the flow channel, and similarly, a dimension of the trap 21 in the first radial direction Y is a width of the trap 21. It is to be understood that fig. 1 is only an example of a flow channel structure, the flow channel is not limited to the one shown in fig. 1, and when the shape of the flow channel or the like is changed, the first radial direction Y and the axial direction X may be changed, but for any straight area of a flow channel, the axial direction and the first radial direction of the area are always perpendicular.

In the same first radial direction Y, the width of the second flow channel 11b is always smaller than the width of the third flow channel 11c in the same radial direction, i.e., the maximum width of the second flow channel 11b is smaller than the minimum width of the third flow channel 11 c. Therefore, it can be seen that, when the width of the second flow channel 11b is different from the width of the third flow channel 11c, microbeads with different sizes in the sample can enter the flow channels with different widths, so that separation of microbeads with different sizes in the sample is realized. After the sample flows through the first flow channel 11a, the microbeads having the largest size smaller than the width of the second flow channel 11b in the sample can enter the second flow channel 11b, and the other microbeads having the size larger than the width of the second flow channel 11b in the sample cannot enter the second flow channel 11b, and then enter the third flow channel 11c along the fluid direction. It can be seen that the second flow channel 11b separates the microbeads having the largest size smaller than the width of the second flow channel 11b from the sample, thereby achieving separation of the microbeads in the sample.

In the present embodiment, the trap portion 20 includes a trap 21, the trap 21 is located at the second end of the second flow channel 11b, the width of the second flow channel 11b is smaller than or equal to the width of the trap 21 in the same direction, and the depth of the trap 21 is greater than the depth of the second flow channel 11b in the direction perpendicular to the plane of the flow channel structure 1. The width refers to a width in a first radial direction Y parallel to a plane of the flow channel structure, and the depth refers to a width in a second radial direction Z perpendicular to the plane of the flow channel structure. The depth of the trap 21 is greater than that of the second flow channel 11b, so that the microbeads in the sample enter the trap 21 after passing through the second flow channel 11b, and the trapped microbeads can be stored in the trap 21, thereby preventing the trapped microbeads from flowing back into the second flow channel 11b from the trap 21. If the depth of the trap 21 is different in different regions, it will be appreciated that the maximum depth of the trap 21 is greater than the maximum depth of the second channel 11 a.

The microfluidic device provided by the embodiment of the invention has at least one stage of flow channel structure, and a sample containing microbeads enters a first flow channel of the flow channel structure and then flows to a second flow channel and a third flow channel through a driving force, wherein the maximum size of the microbeads entering the second flow channel is smaller than the width of the second flow channel, and the remaining samples enter the third flow channel, so that the microbeads with the maximum size smaller than the width of the second flow channel are separated from the sample by the second flow channel, and the separation of the microbeads in the sample is realized. The separated microbeads flow in the second flow channel and are obtained at the trap, the depth of the trap is greater than that of the second flow channel, so that the microbeads entering the trap are not easy to flow out, and the separated microbeads are captured through the gradient depth of the flow channel structure. According to the embodiment of the invention, the microfluidic device can realize the functions of separating and capturing the microbeads in the sample, and has the advantages of low cost, simple operation steps, high efficiency and almost no pollution risk.

For example, fig. 3 is a schematic diagram of a multi-stage flow channel structure, and based on the above technical solution, the microfluidic device shown in fig. 3 may be selected to include a multi-stage cascade flow channel structure, and the third flow channel 11c of the upper-stage flow channel structure 11 is multiplexed into the first flow channel 12a of the lower-stage flow channel structure 12.

In this embodiment, for the upper flow channel structure 11, the second flow channel 11b separates beads having a maximum size smaller than the width thereof from the sample, and the other sample flows into the third flow channel 11c, and the third flow channel 11c is multiplexed as the first flow channel 12a of the lower flow channel structure 12. In the lower flow channel structure 12, the remaining sample separated by the upper flow channel structure 11 enters the first flow channel 12a of the lower flow channel structure 12, and the beads in the sample are separated again by the second flow channel 12b and the third flow channel 12 c. It is understood that, in each stage of flow channel structure, the width of the second flow channel is smaller than that of the third flow channel, and separation and capture of microbeads having a size condition smaller than or equal to that of the second flow channel can be achieved. Thus, the multi-level separation and the acquisition of various microbeads with different sizes are carried out on the microbeads in the sample through the multi-level cascaded flow channel structure.

In the selectable multi-stage cascade flow channel structure, at least two adjacent stages of flow channel structures exist, and the widths of the second flow channels are the same; and/or at least two adjacent stages of flow channel structures exist in the multi-stage cascaded flow channel structures, and the widths of the second flow channels are different.

Referring to fig. 3, in the multi-stage cascade flow channel structure, the widths of the second flow channels of the adjacent two-stage flow channel structures are different. Alternatively, the width of the second flow channel 11b of the upper stage flow channel structure 11 is larger than the width of the second flow channel 12b of the lower stage flow channel structure 12. The second flow channel 11b of the upper flow channel structure 11 separates microbeads having a size smaller than or equal to the width of the second flow channel 11b from the sample, and the remaining separated sample flows into the lower flow channel structure 12. The second flow channel 12b of the lower flow channel structure 12 separates microbeads having a size smaller than or equal to the width of the second flow channel 12b from the sample, and traps the separated microbeads. The upper and lower two-stage flow channel structure realizes the separation and acquisition of microbeads with different size conditions.

In other embodiments, the width of the second flow channel of the upper-stage flow channel structure in the adjacent two-stage flow channel structure may be smaller than the width of the second flow channel of the lower-stage flow channel structure, so that the multi-stage cascaded flow channel structure can perform multi-stage separation and extraction on microbeads in a sample from small to large.

Referring to fig. 4, fig. 4 is a schematic diagram of a second multi-stage flow channel structure, in the multi-stage cascade flow channel structure, the widths of the second flow channels of at least two stages of flow channel structures are the same, and then through the at least two stages of flow channel structures, microbeads with the size smaller than or equal to the width of the second flow channel in the sample can be separated and captured more than twice, so that the separation purity of the microbeads with the size condition is improved. For example, the second flow channels 11b of the upper stage flow channel structure 11 and the second flow channels 12b of the lower stage flow channel structure 12 have the same width, and the upper stage flow channel structure 11 and the lower stage flow channel structure 12 having the same width of the second flow channels may be adjacent or not adjacent.

In the embodiment of the invention, at least two stages of completely identical flow channel structures or at least two stages of completely different flow channel structures can exist in the multi-stage cascaded flow channel structure, and related practitioners can reasonably set the flow channel structures according to actual needs.

Alternatively, as shown in fig. 5, fig. 5 is a schematic view of a flow channel structure, where the extending direction of the first flow channel 11a is the same as the extending direction of the second flow channel 11b, and the connecting direction of the first end and the second end of the third flow channel 11c intersects with the extending direction of the first flow channel 11 a. The first flow channel 11a, the second flow channel 11b and the third flow channel 11c are all straight flow channels. The extending direction of the first flow channel 11a is the same as the extending direction of the second flow channel 11b, and the sample driving path is a straight line, so that the second flow channel 11b can separate microbeads with the size smaller than or equal to the width of the microbeads in the sample. The connecting line direction of the first end and the second end of the third flow channel 11c intersects with the extending direction of the first flow channel 11a, and then the separated residual sample is driven to flow into the third flow channel 11 c.

As shown in fig. 6, fig. 6 is a schematic view of a second flow channel structure, the third flow channel includes a bending portion 111c and a straight portion 112c, an extending direction of the bending portion 111c intersects an extending direction of the straight portion 112c, the bending portion 111c includes a first end of the bending portion and a second end of the bending portion, the second end of the bending portion is communicated with the straight portion 112c, and the first end of the bending portion is communicated with the second end of the first flow channel 11 a. Optionally, the first flow channel 11a and the second flow channel 11b are both straight flow channels. The extending direction of the first flow channel 11a is the same as the extending direction of the second flow channel 11b, and the sample driving path is a straight line, so that the second flow channel 11b can separate microbeads with the size smaller than or equal to the width of the microbeads in the sample.

The third flow channel is a bent flow channel, which includes a bent portion 111c and a straight portion 112c, the bent portion 111c is bent to communicate the first flow channel 11a with the straight portion 112c of the third flow channel, so that the extending direction of the bent portion 111c intersects with the extending direction of the first flow channel 11a, and the extending direction of the bent portion 111c also intersects with the extending direction of the straight portion 112 c.

In this embodiment, the extending direction of the straight portion 112c of the optional third flow channel is the same as the extending direction of the first flow channel 11a, and in other embodiments, the extending direction of the straight portion of the optional third flow channel may intersect with the extending direction of the first flow channel.

Referring to fig. 7, fig. 7 is a schematic view of a third multi-stage flow channel structure, and the microfluidic device includes a multi-stage cascade flow channel structure, where the straight portion 112c of the third flow channel of the upper-stage flow channel structure 11 is multiplexed as the first flow channel 12a of the lower-stage flow channel structure 12.

In this embodiment, in the upper flow channel structure 11, the beads having the largest size smaller than the width thereof are separated from the sample in the second flow channel 11b, the other sample flows into the third flow channel, and the straight portion 112c of the third flow channel is multiplexed as the first flow channel 12a of the lower flow channel structure 12. With respect to the lower flow channel structure 12, the remaining sample separated by the upper flow channel structure 11 all enters the first flow channel 12a of the lower flow channel structure 12, and then the microbeads in the sample are separated again through the second flow channel 12b and the third flow channel 12c thereof. It is understood that, in each stage of flow channel structure, the width of the second flow channel is smaller than that of the third flow channel, and separation and capture of microbeads having a size condition smaller than or equal to that of the second flow channel can be achieved. Thus, the multi-level separation and the acquisition of various microbeads with different sizes are carried out on the microbeads in the sample through the multi-level cascaded flow channel structure.

In the selectable multi-stage cascade flow channel structure, at least two adjacent stages of flow channel structures exist, and the widths of the second flow channels are the same; and/or at least two adjacent stages of flow channel structures exist in the multi-stage cascaded flow channel structures, and the widths of the second flow channels are different.

Referring to fig. 7, in the multi-stage cascade flow channel structure, the widths of the second flow channels of the adjacent two-stage flow channel structures are different. The upper and lower two-stage flow channel structure realizes the separation and acquisition of the microbeads with different size conditions.

In other embodiments, the flow channel structure may also be selected from a multi-stage cascade flow channel structure, and the widths of the second flow channels of at least two stages of flow channel structures are the same, so that beads with a size smaller than or equal to the width of the second flow channel in a sample can be separated and captured twice or more by the at least two stages of flow channel structures, thereby improving the separation purity of the beads with the size condition.

It should be noted that the flow channel structure of the multistage cascade includes, but is not limited to, the above structure, for example, there is a two-stage flow channel structure, where the third flow channel of the one-stage flow channel structure is a straight flow channel, and the third flow channel of the other-stage flow channel structure includes a bending portion and a straight portion, and related practitioners can reasonably set the flow channel structure according to actual needs.

For example, fig. 8 is a schematic diagram of a third flow channel structure, and based on the above technical solution, the trap portion shown in fig. 8 may optionally include a trap flow channel 22, the trap flow channel 22 communicates with the trap 21 in a direction parallel to a plane of the flow channel structure, a depth of the trap flow channel 22 is the same as a depth of the trap 21, and a width of the trap flow channel 22 is greater than or equal to a width of the second flow channel 11 b. The trap flow path 22 includes a straight portion which penetrates the trap 21 in the axial direction thereof. As shown in fig. 8, a trap flow channel 22 communicates with a trap 21 in a direction parallel to the plane of the flow channel structure, so that the trap flow channel 22 flows through a trap 21.

The trap 21 is used for capturing the microbeads separated by the second flow channel 11b, and the trap flow channel 22 can be used as an extraction path of the separated microbeads, so that the microbeads captured by the trap 21 can be conveniently extracted through the trap flow channel 22 in the subsequent extraction process. Therefore, the depth of the trap flow channel 22 is the same as the depth of the trap 21, and the width of the trap flow channel 22 is greater than or equal to the width of the second flow channel 11b, so that the microbeads captured in the trap 21 can move into the trap flow channel 22 under the driving force, and the captured microbeads are extracted, thereby preventing the microbeads captured by the trap 21 from returning to the second flow channel 11 b.

Fig. 9 is a schematic view of a fourth flow channel structure, and an alternative flow channel section as shown in fig. 9 comprises at least two second flow channels 11b, and the trap flow channel 22 of the trap section penetrates each trap 21 in turn in a direction parallel to the plane of the flow channel structure. The trap channel 22 flows through each trap 21 through which it passes in turn, alternatively one trap channel 22 flows through two traps 21 as shown in figure 9.

Fig. 10 is a schematic view of a fifth flow channel structure, and an alternative flow channel section as shown in fig. 10 includes at least two second flow channels 11b, and a trap flow channel 22 of the trap section penetrates one trap 21 in a direction parallel to the plane of the flow channel structure. The trap part includes at least two trap flow channels 22, and one trap flow channel 22 flows through one trap 21.

In this embodiment, the selectable first-stage flow channel structure includes at least two second flow channels 11b having the same width, and the size conditions of the microbeads to be separated in the two or more second flow channels 11b in the first-stage flow channel structure are the same and are the microbeads of which the maximum size is smaller than that of the second flow channels 11b in the sample, so that the obtaining efficiency of the microbeads of the size conditions can be improved.

In other embodiments, the first-stage flow channel structure may further include at least two second flow channels with different widths, and the two or more second flow channels in the first-stage flow channel structure are used for separating microbeads with different size conditions, so that the efficiency of obtaining microbeads with different size conditions in a sample may be improved. It can be understood that when the width of the second flow channel changes, both the trap and the trap flow channel at the second end of the second flow channel may change, so that in the same flow channel structure, when two second flow channels exist and have different widths, the trap flow channels corresponding to the two second flow channels having different widths are different.

In this embodiment, the first-stage flow channel structure may further include at least two third flow channels 11c symmetrically distributed, and the straight portion of the third flow channel 11c may be reused as the first flow channel of the next-stage flow channel structure. The plurality of third flow channels 11c are arranged in the primary flow channel structure, so that the driving efficiency of the separated residual sample in the primary flow channel structure can be improved.

For the primary flow path structure, when the flow path portion thereof is provided with two or more second flow paths 11b, and the second end of each second flow path 11b is provided with one trap 21, the trap flow path 22 of the trap portion in the primary flow path structure may sequentially penetrate through each trap 21 in the first radial direction Y of the second flow path 11b, so that the traps 21 of the second end of the second flow path 11b communicate. Thus, the trap flow channel 22 can extract the microbeads captured in the trap 21 communicated with the second end of the second flow channel 11b, even the microbeads enter the trap flow channel 22 from the trap 21 and are discharged out of the flow channel structure, the extraction of the microbeads is realized, the extraction efficiency of the microbeads is improved, and the structure of the trap part is simplified.

Fig. 11 is a schematic view of a fourth multi-stage flow channel structure, and an alternative microfluidic device as shown in fig. 11 includes a multi-stage cascade of flow channel structures, in which at least two adjacent stages of flow channel structures exist, and the widths of the second flow channels are the same; the trap flow channel of the adjacent two-stage flow channel structure is communicated with the first end, and/or the trap flow channel of the adjacent two-stage flow channel structure is communicated with the second end.

In this embodiment, the microfluidic device includes a multi-stage cascade of flow channel structures, and fig. 11 shows two adjacent stages of flow channel structures 11 and 12. The third flow passage 11c of the upper stage flow passage structure 11 communicates with the first flow passage 12a of the lower stage flow passage structure 12. For the upper-stage flow channel structure 11, after the microbeads with the maximum size smaller than or equal to the width of the second flow channel in the sample are separated by the second flow channel 11b, the rest of the sample enters the third flow channel 11 c. And then enters the first flow channel 12a of the lower flow channel structure 12, and for the lower flow channel structure 12, after the microbeads with the maximum size smaller than or equal to the width of the second flow channel in the sample are separated by the second flow channel 12b, the rest of the sample enters the third flow channel 12 c.

In the two adjacent-stage flow channel structures 11 and 12, the widths of the second flow channels 11b and 12b are the same, so that the size conditions of the separated microbeads are the same, and the microbeads are all microbeads with the size smaller than or equal to the width of the second flow channel 11b, so that the sizes of the corresponding trap flow channels 22a and 22b can be the same. The bead separated in the second flow path 11b enters the trap 21a, and the bead trapped in the trap 21a can be extracted by driving the trap flow path 22 a. One end of the trap flow channel 22a and one end of the trap flow channel 22b of the adjacent two-stage flow channel structure are shared, microbeads with the same size condition in the adjacent two-stage flow channel structure can be extracted at the same time, and the extraction efficiency of the microbeads is improved.

Fig. 12 is a schematic view of a microfluidic device, and fig. 13 is a cross-sectional view taken along B-B' of fig. 12. Illustratively, on the basis of the above technical solutions, the microfluidic device shown in fig. 12 and 13 optionally includes a first substrate 100 and a second substrate 200 bonded on the first substrate 100, and the at least one stage of flow channel structure 1 is disposed on a surface of the first substrate 100 facing the second substrate 200. Optionally, the first substrate 100 and the second substrate 200 are both glass substrates, which is convenient for a tester to observe sample flow and bead separation. It should be noted that fig. 12 is a plan view from directly above the second substrate 200, and in a normal case, the flow channel structure is blocked by the second substrate 200 and cannot be displayed, but in fig. 12, in order to illustrate the position of the flow channel structure in the substrate, the flow channel structure is shown on the second substrate 200, and the outline of the flow channel structure is represented by a dotted line to indicate that the flow channel structure is located inside the substrate, but not on the surface of the second substrate 200. The specific location of the flow channel structure in the substrate can be clearly understood by those skilled in the art according to fig. 12&13 or fig. 12&14, and will not be described herein again.

The trap portion 20 of the flow channel structure 1 is formed on the surface of the first substrate 100 by etching, and then the trap portion 20 is etched twice and the flow channel portion 10 is formed by etching, so that the trap portion 20 is formed by etching twice, and the flow channel portion 10 is formed by etching once. The trap portion 20 of the flow path structure 1 thus fabricated is formed to have a depth greater than that of the flow path portion 10. Then, a second substrate 200 is bonded to the surface of the first substrate 100 on which the flow channel structure 1 is fabricated, so as to form a sealed flow channel structure 1. Optionally, the flow channel structure 1 is formed by performing secondary etching on the first substrate, so that the gradient depth of the flow channel structure 1 can be realized.

In the bead separation stage in the sample, the sample to be separated is injected into the microfluidic device, the sample flows in the flow channel part 10 of the flow channel structure 1 by a driving force, the beads are captured at the trap part 20 located at the second end of the second flow channel, and other samples flow out through the third flow channel. It will be appreciated that the number of second flow channels in the flow channel structure 1 may be one or more and the corresponding number of traps may be one or more. The level of the flow channel structure 1 may be one or more stages.

As mentioned above, the flow channel structure of the microfluidic device is simple to manufacture and low in cost, the operation for separating the microbeads in the sample is simple and easy to operate, the pollution of the sample and the microbeads separated from the sample by the outside can be avoided, and the purity and the efficiency of separating and extracting the microbeads in the sample are improved.

Fig. 14 is a second cross-sectional view taken along line B-B' of fig. 12, and an alternative microfluidic device as shown in fig. 14 includes a first substrate 100 and a second substrate 200 bonded to the first substrate 100; in the flow path structure 1, the flow path portion 10 is provided on a surface of the second substrate 200 facing the first substrate 100, and the trap portion 20 is provided on a surface of the first substrate 100 facing the second substrate 200.

The trap part 20 of the flow path structure 1 is formed on the surface of the first substrate 100 by means of primary etching, and the flow path part 10 of the flow path structure 1 is formed on the surface of the second substrate 200 by means of primary etching. Then, the second substrate 200 is bonded on the first substrate 100 in an alignment manner, specifically, the surface of the first substrate 100 on which the trap portion 20 is formed and the surface of the second substrate 200 on which the flow channel portion 10 is formed are bonded, so that the sealed flow channel structure 1 is formed at the bonding surface of the first substrate 100 and the second substrate 200, and details of the alignment manner are not repeated. The runner part 10 and the trap part 20 of the runner structure 1 are manufactured on two substrates, the two substrates are respectively etched once and then are aligned and bonded, and the efficiency of batch production can be improved.

It is understood that an orthographic projection of the second end of the flow channel portion 10 in the direction perpendicular to the first substrate overlaps the trap portion 20, and the bead in the sample can fall into the trap of the trap portion 20 through the second flow channel of the flow channel portion 10, so that the bead can be captured.

Optionally, the distance between the bonding interface of the two substrates and the surface of the first substrate facing away from the second substrate decreases gradually in the direction in which the first end of the flow channel points towards the second end.

Fig. 15 is a third sectional view taken along line B-B' of fig. 12, and as shown in fig. 15, the flow path structure 1 is formed on a substrate 100. The distance between the bonding interface of the two substrates and the bottom surface of the first substrate 100 is gradually decreased in a direction in which the first end of the flow channel is directed to the second end. The bottom surface of the first substrate 100 is usually placed on a horizontal platform, and then the bonding interface of the two substrates has a slope, and the first end of the flow channel is located at a height higher than that of the horizontal platform than that of the second end of the flow channel, so that the slope of the bonding interface of the two substrates can assist the sample to flow when the sample flows from the first end to the second end of the flow channel.

Fig. 16 is a fourth sectional view taken along B-B' in fig. 12, and as shown in fig. 16, the runner section 10 and the trap section 20 of the runner structure 1 are located on different substrates. The distance between the bonding interface of the two substrates and the bottom surface of the first substrate 100 is gradually decreased in a direction in which the first end of the flow channel is directed to the second end. The bottom surface of the first substrate 100 is usually placed on a horizontal platform, and then the bonding interface of the two substrates has a slope, and the first end of the flow channel is located at a height higher than that of the horizontal platform than that of the second end of the flow channel, so that the slope of the bonding interface of the two substrates can assist the sample to flow when the sample flows from the first end to the second end of the flow channel.

The selectable microfluidic device includes a first stage flow channel structure and a last stage flow channel structure, a first end of a first flow channel of the first stage flow channel structure extends to a side of the microfluidic device, and a second end of a third flow channel of the last stage flow channel structure extends to a side of the microfluidic device. In other embodiments, the microfluidic device may further include only one stage of flow channel structure, and then the stage of flow channel structure is a first stage of flow channel structure and is also a last stage of flow channel structure, where a first end of the first flow channel of the stage of flow channel structure is reused as a first end of the first flow channel of the first stage of flow channel structure, and a second end of the third flow channel of the stage of flow channel structure is reused as a second end of the third flow channel of the last stage of flow channel structure.

The microfluidic device is described herein as including a two-stage cascade of flow channel structures. Fig. 17 is a schematic diagram of a fifth multi-stage flow channel structure, as shown in fig. 17, a side surface of the first end of the first flow channel 1Fa of the optional first-stage flow channel structure 1F extending is the same as a side surface of the second end of the third flow channel 1Mc of the last-stage flow channel structure 1M extending, and then a bending portion exists in the third flow channel, such as 1Mc, inside the at least one-stage flow channel structure, so that after passing through the multi-stage cascaded flow channel structure, the second end of the third flow channel 1Mc of the last-stage flow channel structure 1M and the first end of the first flow channel 1Fa of the first-stage flow channel structure 1F extend to the same side surface.

Fig. 18 is a schematic view of a sixth multi-stage flow channel structure, and as shown in fig. 18, the first end of the first flow channel 1Fa of the optional first-stage flow channel structure 1F extends to a side adjacent to the second end of the third flow channel 1Mc of the last-stage flow channel structure 1M.

Fig. 19 is a schematic view of a seventh multi-stage flow channel structure, and as shown in fig. 19, the side from which the first end of the first flow channel 1Fa of the optional first-stage flow channel structure 1F extends is opposite to the side from which the second end of the third flow channel 1Mc of the last-stage flow channel structure 1M extends.

It can be understood that the number of stages of the flow channel structure in the microfluidic device, the shape, the number of traps, and the like of each stage of the flow channel structure can be adjusted according to actual product requirements, and is not limited to the limitations of any of the above embodiments.

The selectable microfluidic device is provided with a liquid injection hole, the microfluidic device comprises a first-stage flow channel structure and a last-stage flow channel structure, and the liquid injection hole penetrates through the first substrate or the second substrate until the first end of the first flow channel of the first-stage flow channel structure is exposed; the micro-fluidic device is provided with a liquid outlet hole which penetrates through the first substrate or the second substrate until the second end of the third flow channel of the final-stage flow channel structure is exposed. The microfluidic device is described herein as including a two-stage cascade of flow channel structures. In other embodiments, the microfluidic device may further include only one stage of flow channel structure, and the stage of flow channel structure is a first stage of flow channel structure and is also a last stage of flow channel structure; the liquid injection hole penetrates through the substrate and exposes the first end of the first flow channel of the stage flow channel structure, and the liquid outlet hole penetrates through the substrate and exposes the second end of the third flow channel of the stage flow channel structure.

Referring to fig. 20 and fig. 13, fig. 20 is a schematic view of an eighth multi-stage flow channel structure, and the alternative flow channel structure 1 is formed on the surface of the first substrate 100, so that the liquid injection hole 11d penetrates through the second substrate 200 bonded to the first substrate 100 until the first end of the first flow channel 11a of the first-stage flow channel structure is exposed. The microfluidic device has a liquid outlet hole 11e, and the liquid outlet hole 11e penetrates through the first substrate 100 until the second end of the third flow channel 12c of the final stage flow channel structure is exposed. And injecting a sample into the first flow channel 11a of the first-stage flow channel structure through the liquid injection hole 11d, so that the sample flows in the multi-stage cascaded flow channel structure, the microbeads with the size smaller than the width of the sample are separated from the second flow channel of each stage of flow channel structure, and the residual sample after separation is discharged out of the flow channel structure through the liquid outlet hole 11e at the second end of the third flow channel 12c of the last-stage flow channel structure.

As shown in fig. 14 and 20, the trap portion of the optional flow channel structure 1 is formed on the surface of the first substrate 100, the flow channel portion of the flow channel structure 1 is formed on the surface of the second substrate 200, and the flow channel portion and the trap portion are bonded in alignment to constitute the flow channel structure. The liquid injection hole 11d penetrates the second substrate 200 bonded to the first substrate 100 until the first end of the first flow channel 11a of the primary flow channel structure is exposed. The microfluidic device has a liquid outlet hole 11e, and the liquid outlet hole 11e penetrates through the first substrate 100 until the second end of the third flow channel 12c of the final stage flow channel structure is exposed. And injecting a sample into the first flow channel 11a of the first-stage flow channel structure through the liquid injection hole 11d, so that the sample flows in the multi-stage cascaded flow channel structure, the microbeads with the size smaller than the width of the sample are separated from the second flow channel of each stage of flow channel structure, and the residual sample after separation is discharged out of the flow channel structure through the liquid outlet hole 11e at the second end of the third flow channel 12c of the last-stage flow channel structure.

It is understood that the liquid injection hole of the microfluidic device may also extend through the first substrate, or the liquid outlet hole may extend through the second substrate, and the related practitioner may set the liquid injection hole and the liquid outlet hole according to the requirement of the test, not limited to the above examples.

The selectable trap part comprises a trap flow channel, and the trap flow channel penetrates through the trap in a direction parallel to the bonding interface of the two substrates; the micro-fluidic device is provided with an air inlet hole and an air outlet hole, the air inlet hole penetrates through the first substrate or the second substrate until the first end of the trap flow channel is exposed, and the air outlet hole penetrates through the first substrate or the second substrate until the second end of the trap flow channel is exposed.

As shown in fig. 13 and 20, an optional trap flow channel 22 penetrates each trap 21 at the second flow channel in the present stage flow channel structure in a direction parallel to the bonding interface of the two substrates. The trap 21 is used for capturing each bead flowing out of the second flow channel, and the trap flow channel 22 is used for extracting each bead stored in the trap 21. Holes may be optionally punched in the second substrate 200, one through hole communicating to a first end of the trap flow path 22 as an inlet hole 23, and the other through hole communicating to a second end of the trap flow path 22 as an outlet hole 24. The inert gas is injected from the gas inlet hole 23, the microbeads in the trap 21 are filled in the trap flow channel 22 by the inert gas, and the gas outlet hole 24 on the other side applies suction force to extract the microbeads in the trap flow channel 22.

In other embodiments, holes may be punched in the first substrate to form an air inlet hole connected to the first end of the trap flow channel, and an air outlet hole connected to the second end of the trap flow channel. Or, the first substrate can be perforated to be communicated to the first end of the trap flow channel, the second substrate can be perforated to be communicated to the second end of the trap flow channel, and two through holes at two ends of the trap flow channel can be respectively used as an air outlet hole and an air inlet hole. The aperture of the optional liquid injection hole, the liquid outlet hole, the air inlet hole and the air outlet hole is smaller than that of the trap.

Thereby, extraction of the microbeads is achieved. The extraction process is simple to operate, high in efficiency and hardly produces pollution, and the purity of the extracted microbeads is guaranteed.

Based on the same inventive concept, the embodiment of the present invention further provides a manufacturing method of the microfluidic device, and the manufacturing method can be used for manufacturing the microfluidic device described in any of the above embodiments. Fig. 21 is a schematic view of a method for manufacturing a microfluidic device according to an embodiment of the present invention, and as shown in fig. 21, the method for manufacturing a microfluidic device includes:

s1, providing a first substrate and a second substrate;

s2, etching for the first time on the first substrate to form a trap part;

s3, carrying out first etching on the second substrate to form the runner part, or exposing the trap part and carrying out second etching on the first substrate to form the runner part; the flow channel part comprises a first flow channel, a second flow channel and a third flow channel, each flow channel is provided with a first end and a second end, the first end of the second flow channel and the first end of the third flow channel are communicated to the second end of the first flow channel, the width of the second flow channel is smaller than that of the third flow channel, and the width of the flow channel is the size of the flow channel in the direction perpendicular to the extending direction of the flow channel in the plane of the flow channel structure; the trap part comprises a trap, the trap is positioned at the second end of the second flow channel, the width of the second flow channel is smaller than or equal to the width of the trap in the same direction, and the depth of the trap is larger than that of the second flow channel in the direction perpendicular to the plane of the flow channel structure;

and S4, bonding the first substrate and the second substrate, and aligning the trap part and the flow channel part to form a flow channel structure.

In this embodiment, the flow channel structure may be etched by PVD, Photo, Etch, or other processes.

Fig. 22 is a schematic diagram of a manufacturing structure of a microfluidic device, and referring to fig. 22, a first etching is performed on a first substrate 100 to form a trap portion 20 of a flow channel structure of each stage, and further, an inlet hole and an outlet hole of the trap portion 20 are optionally formed. Then, the trap portion 20 is exposed, and a second etching is performed on the first substrate 100 to form the runner portion 10 of each stage of runner structure, and optionally, a liquid injection hole and a liquid outlet hole of the runner portion 10 are formed, where the second etching continues to etch the first etched trap portion 20 downward, so that the depth of the second etched trap portion 20 is obviously greater than the depth of the first etched runner portion 10. Finally, the first substrate 100 and the second substrate are bonded. It can be understood that at least one through hole of the air inlet hole, the air outlet hole, the liquid injection hole and the liquid outlet hole can also be formed on the second substrate or extend to any side surface of the microfluidic device; the process step of punching may also be performed after bonding the substrates. It is to be understood that the runner section 10 may include a runner section of a multi-stage runner structure, and the trap section 20 may include a trap section of a multi-stage runner structure.

Fig. 23 is a schematic view showing another structure of manufacturing a microfluidic device, and referring to fig. 23, an etching process is performed on the first substrate 100 to form the trap portion 20 of each stage of the flow channel structure, and further to optionally form the inlet and outlet holes of the trap portion 20. The second substrate 200 is etched once to form the runner section 10, and optionally, a liquid injection hole and a liquid discharge hole of the runner section 10 are formed again. Finally, the first substrate 100 and the second substrate 200 are bonded. It is understood that the runner section 10 and the trap section 20 are etched on different substrates, respectively, and thus the two etching steps are independent of each other without the steps being separated in sequence. In addition, at least one through hole of the air inlet hole and the air outlet hole can be formed on the second substrate 200, and at least one through hole of the liquid inlet hole and the liquid outlet hole can be formed on the first substrate 100 or extend to any side surface of the microfluidic device; the process step of punching may also be performed after bonding the substrates.

It can be understood that the first-stage flow channel structure is formed by two etching processes in total; in other embodiments, the etching process times of different levels of flow channel structures can be selected to be different. For example, a final stage runner structure is formed firstly, then the final stage runner structure is exposed, on the basis, a penultimate stage runner structure is formed by adopting at least one etching process, and by analogy, the etching depth of the first stage runner structure is the shallowest, and the etching depth of the upper stage runner is smaller than that of the lower stage runner, so that a multi-gradient runner structure can be formed. Of course, there may be at least two adjacent stages of the multi-gradient channel structure having the same gradient.

The embodiment provides a manufacturing method of a micro-fluidic device, wherein the first-stage runner structure adopts two etching process procedures, the manufacturing process is simple, the etching process is mature, and etching parameters such as etching depth and width can be accurately controlled.

Based on the same inventive concept, the embodiment of the invention also provides an extraction method of the microfluidic device, and the extraction method can be used for extracting the microbeads separated by the microfluidic device in any embodiment. Fig. 24 is a schematic diagram of an extraction method of a microfluidic device according to an embodiment of the present invention, fig. 25 is a schematic diagram of a liquid injection stage of the microfluidic device, and fig. 26 is a schematic diagram of an extraction stage of the microfluidic device, where, as shown in fig. 24, 25, and 26, a trap portion of the microfluidic device further includes a trap flow channel, and the trap flow channel communicates with a trap in a direction parallel to a plane of a flow channel structure; the extraction method comprises the following steps:

s10, injecting a sample to be detected into the first flow channel in a liquid injection stage, and enabling microbeads to be extracted in the sample to be detected to enter the trap through the second flow channel;

and S20, in the extraction stage, filling inert gas into the first end of the trap flow channel, and discharging the microbeads in the trap through the second end of the trap flow channel.

Referring to fig. 25, in the liquid injection stage, a sample to be tested is injected into the first flow channel 11a of the first-stage flow channel structure through the liquid injection hole 11d, and the second flow channels 11b and 12b of each stage of flow channel structure separate and capture microbeads from the sample to be tested, wherein the size of the microbeads extracted by the second flow channels 11b and 12b is smaller than or equal to the width of the flow channels. The second flow channels of the multi-stage flow channel structure are used for separating and capturing microbeads in a sample to be detected, and if the widths of the second flow channels of at least two stages of flow channel structures are different, the microfluidic device can be used for acquiring microbeads with at least two different sizes; if the widths of the second flow channels of at least two adjacent flow channel structures are the same, the at least two adjacent flow channel structures can realize multiple times of obtaining of microbeads with the same size condition, and the precision of obtaining the microbeads with the size condition from a sample is improved. Finally, the liquid outlet hole 11e at the second end position of the third flow channel 12c of the final stage flow channel structure discharges the sample remaining after the separation.

Referring to fig. 26, in the extraction stage, inert gas is injected into the trap flow channel 22 of the flow channel structure through the gas inlet hole 23, so that the bead stored in each stage of the flow channel structure is driven from the trap 21 into the trap flow channel 22, and the bead can be captured from the trap flow channel 22 by applying suction through the gas outlet hole 24. Thereby realizing the extraction of the micro-beads in the trap. In other embodiments, if two adjacent flow channel structures are used to obtain microbeads with the same size, the air outlet hole or the air inlet hole of the trap flow channel of the two adjacent flow channel structures may be shared.

Fig. 27 is a schematic diagram of another extraction method of a microfluidic device according to an embodiment of the present invention, fig. 28 is a schematic diagram of a cleaning stage of the microfluidic device, and optionally, as shown in fig. 27 and 28, further includes: s30, a cleaning step, in which an inert gas is injected into the second end of the third flow channel to discharge the sample remaining in the flow channel part through the first end of the first flow channel.

After bead retrieval or extraction is completed, proceeding to the flow channel cleaning stage, the operation of optional S30 may be performed after S10 or S20. And in the cleaning stage, inert gas is filled into the second end of the third flow channel 12c of the final-stage flow channel structure through the liquid outlet hole 11e, and then the inert gas reversely enters the flow channel structure, finally enters the first flow channel 11a of the first-stage flow channel structure and is discharged from the liquid inlet hole 11d at the first end of the first flow channel 11a, so that the pipe wall of the flow channel part can be cleaned, the separation purity of a next sample is ensured, and microbeads of the trap part cannot be influenced.

The extraction method provided by the embodiment can realize the function of obtaining the microbeads, improve the efficiency and reduce the pollution.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.