Microfluidic chip, device and application

Abstract

The application provides a microfluidic chip, device and application, and innovatively combines droplet microfluidic sorting and droplet fusion technology, generates large droplets in a back-end target droplet pipeline by incorporating culture medium, widens the inner diameter of the fusion pipeline to reduce the flow rate, causes the target droplets and reagent droplets to collide, and then applies an electric field by using the alternating electrodes to change the surface tension of the target droplets and reagent droplets, so that the target droplets and reagent droplets are fused, so that the small droplets are enlarged into large droplets, and the large droplets generated by fusion are controlled, so that the droplets are conveniently controlled.

Description

Technical Field

[0001] This invention relates to the field of microfluidics, specifically to a microfluidic chip, device, and application. Background Technology

[0002] Existing droplet sorting systems typically allow positive or negative droplets in the oil phase to flow out spontaneously with the oil phase after sorting out positive or negative droplets. Since the droplets are relatively small (tens of micrometers in diameter) and there is a density difference between the droplets and the oil phase, the following problems may occur: (1) The sorted droplets are prone to remain in the droplet channel and are difficult to drip out smoothly, resulting in residual lag. This residual lag can cause the droplet flow time to be inconsistent, making it difficult to accurately distribute them to the orifice plate, and it can also cause the sorted droplets and the orifice plate holes to lose their correspondence; (2) Even if there is no residual lag, when the droplets reach the pipeline outlet, due to the surface tension limitation, the small droplets cannot drip smoothly, resulting in a large accumulation at the end of the pipeline, making it impossible to collect the small droplets one by one; (3) Common micro-liquid nozzles, such as piezoelectric ceramic nozzles and solenoid valve nozzles, can spray out liquids of tens of micrometers quickly, but for droplets in microfluidic systems, they often cause droplet breakage and fusion, destroying the integrity of the droplets. Summary of the Invention

[0003] To address the aforementioned problems, this invention amplifies small droplets into large droplets using microfluidic technology, allowing them to flow controllably within a pipeline and drip smoothly from the pipeline end. To this end, this invention provides a microfluidic chip comprising a small droplet sorting unit, a large droplet generation unit, and a fusion unit. The small droplet sorting unit includes a first oil phase inlet, a first oil phase conduit, a first droplet inlet, a first droplet conduit, a sorting conduit, and a sorting electrode. The first oil phase conduit, the first droplet conduit, and the sorting conduit are connected. The oil phase enters the first oil phase conduit through the first oil phase inlet, and the droplets enter the first droplet conduit through the first droplet inlet. The oil phase and droplets flow through the connection point between the first oil phase conduit and the first droplet conduit, forming spaced droplets that move downstream.

[0004] The large droplet generation unit includes a second oil phase inlet, a second oil phase pipe, a first aqueous phase inlet, a first aqueous phase pipe, and a second droplet pipe. The oil phase enters the second oil phase pipe from the second oil phase inlet, and the culture medium or reagent enters the first aqueous phase pipe from the first aqueous phase inlet. The oil phase and the culture medium or reagent flow through the connection between the second oil phase pipe and the first aqueous phase pipe, forming spaced droplets that move downstream.

[0005] The fusion unit includes a negative droplet channel, a fusion channel, and a fusion electrode. The sorting channel, the negative droplet channel, and the fusion channel are connected. The sorting electrode is located at the connection point between the negative droplet channel, the fusion channel, and the sorting channel.

[0006] Preferably, the first oil phase pipeline is divided into two branches from the first oil phase inlet, namely the first oil phase pipeline a and the first oil phase pipeline b, and the first oil phase pipeline a, the first oil phase pipeline b and the sorting pipeline are connected in a cross shape.

[0007] Preferably, the cross-sectional area of ​​the sorting pipe is 4×10⁻⁶. -4 mm 2 -4×10 -2 mm 2 The cross-sectional area of ​​the second droplet channel is 4 × 10⁻⁶. -2 mm 2 -1mm 2 The cross-sectional area of ​​the fusion pipe is 4×10 -2 mm 2 -1mm 2 .

[0008] Preferably, the microfluidic chip is made of one or more of plastic, colloid, or glass.

[0009] The present invention also relates to a microfluidic device, which is any of the microfluidic chips that implement the above-described scheme.

[0010] Preferably, the system includes a sample injection unit, a detection unit, and a dispensing unit. The sample injection unit is connected to the first oil phase injection port, the first droplet injection port, the second oil phase injection port, and the first aqueous phase injection port, respectively. The detection unit is located at the connection point of the sorting pipe, the fusion pipe, and the negative droplet pipe.

[0011] Preferably, the detection unit is one or more of the following: fluorescence detection, optical density detection, Raman detection, infrared detection, scattered light detection, impedance detection, or image recognition device.

[0012] Preferably, the distribution unit includes a pipe support, an X-axis guide rail, an X-axis motor, an X-axis slider, a Y-axis guide rail, a Y-axis motor, a Y-axis slider, and a collection container support. The X-axis motor drives the X-axis slider to move along the X-axis guide rail, the Y-axis motor drives the Y-axis slider to move along the Y-axis guide rail, the Y-axis guide rail is fixedly connected to the X-axis slider, and the collection container support is fixedly connected to the Y-axis slider.

[0013] Preferably, the distribution unit further includes a droplet recovery mechanism, which includes a swing arm, a swing arm motor for controlling the movement of the swing arm, and a waste liquid recovery container disposed on the swing arm.

[0014] This invention also relates to a droplet distribution method, based on the microfluidic device described above, comprising the following steps: S1: Injecting a sample into the microfluidic chip through a sample introduction unit, the oil phase and droplets are separated into small droplets by a small droplet sorting unit and move downstream, wherein the volume of a single small droplet is 10 pL-100 nL (1×10⁻⁶). -5 mm 3 -1×10 -1 mm 3 Simultaneously, the oil phase and culture medium or reagents form spaced large droplets that move downstream through the large droplet generation unit, with each large droplet having a volume of 100 nL-100 μL (1 × 10⁻⁶). -1 mm 3 -1×10 2 mm 3 );

[0015] S2: Drive the small droplets through the detection unit. When a positive droplet is detected, control the sorting electrode to make the positive droplet enter the fusion channel under the action of dielectric force. When a negative droplet is detected, control it to flow to the negative droplet channel. At the same time, continuously drive the large droplet to move downstream.

[0016] S3: When an adjacent positive small droplet and a large droplet flow through the fusion electrode, they fuse into a new target droplet under the action of the electric field.

[0017] S4: The distribution unit distributes the fused positive target droplets and collects and processes the non-target droplets.

[0018] This invention innovatively combines droplet microfluidic sorting and droplet fusion technology. At the rear end, the target droplet channel is integrated with culture medium to generate larger droplets. The inner diameter of the fusion channel is widened to reduce the flow rate, causing the target droplet and reagent droplets to collide. An AC electrode is then used to apply an electric field, altering the surface tension of the target and reagent droplets and causing them to fuse, thus amplifying small droplets into larger ones. By manipulating the fused, larger droplets, droplet control is facilitated, improving cell activity within the target droplet, reducing target droplet loss, and ensuring the steady state of the microfluidic device. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0020] Figure 1 This is a microfluidic chip structure diagram according to an embodiment of the present invention;

[0021] Figure 2 This is a microfluidic chip structure diagram according to an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of a microfluidic device according to an embodiment of the present invention;

[0023] Figure 4 This is a structural diagram of the allocation unit according to an embodiment of the present invention;

[0024] Figure 5 This is a structural diagram of the allocation unit according to an embodiment of the present invention. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0026] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention.

[0029] like Figure 1-2As shown, a microfluidic chip 1 according to an embodiment of the present invention includes a small droplet sorting unit 11, a large droplet generation unit 12, and a fusion unit 13. The small droplet sorting unit 11 includes a first oil phase inlet 111, a first oil phase pipe, a first droplet inlet 112, a first droplet pipe 115, a sorting pipe 15, and a sorting electrode 16. The first oil phase pipe, the first droplet pipe 115, and the sorting pipe 15 are connected. The oil phase enters the first oil phase pipe through the first oil phase inlet 111, and the droplets enter the first droplet pipe 115 through the first droplet inlet 112. The oil phase and droplets flow through the connection between the first oil phase pipe and the first droplet pipe 115, forming spaced droplets that move downstream.

[0030] The large droplet generation unit 12 includes a second oil phase inlet 121, a second oil phase pipe 116, a first aqueous phase inlet 122, and a first aqueous phase pipe 117. The oil phase enters the second oil phase pipe 116 from the second oil phase inlet 121, and the culture medium or reagent enters the first aqueous phase pipe 117 from the first aqueous phase inlet 122. The oil phase and the culture medium or reagent flow through the connection between the second oil phase pipe 116 and the first aqueous phase pipe 117 to form spaced droplets that move downstream.

[0031] The fusion unit 13 includes a negative droplet channel 14, a fusion channel 132, and a fusion electrode 131. The sorting channel 15, the negative droplet channel 14, and the fusion channel 132 are connected and generally form a Y-shaped structure. The sorting electrode 16 is located at the connection point of the three channels: the negative droplet channel 14, the fusion channel 132, and the sorting channel 15.

[0032] The microfluidic chip 1 provided in this embodiment of the invention uses a small droplet sorting unit 11 to generate small droplets from a mixed solution of droplets to be sorted, and a high-voltage sorting electrode 16 to sort positive droplets. A large droplet generating unit 12 generates larger droplets containing culture medium or reagents. Then, the sorted positive droplets and droplets containing culture medium or reagents are driven into a fusion channel 132. Under the action of the fusion electrode 131, the surface charge between the droplets is affected, achieving a fusion effect. The fused droplets are larger and easier to control.

[0033] like Figure 2 As shown, in some embodiments, the first oil phase pipeline includes two branches, namely the first oil phase pipeline a113 and the first oil phase pipeline b114. The first oil phase pipeline a113, the first oil phase pipeline b114 and the sorting pipeline 15 are connected in a cross shape. This design can make the droplet generation process more stable.

[0034] In some embodiments, the cross-sectional area of ​​the sorting pipe 15 is 4 × 10⁻⁶.-4 mm 2 -4×10 -2 mm 2 The cross-sectional area of ​​the second droplet conduit 123 is 4 × 10⁻⁶. -2 mm 2 -1mm 2 The cross-sectional area of ​​the fusion pipe 132 is 4×10 -2 mm 2 -1mm 2 The size of the sorting pipe 15 is smaller than that of the second droplet pipe 123 and the fusion pipe 132. By widening the size of the fusion pipe 132 at the rear end, the flow rate of the positive droplet when it enters the fusion pipe 132 is slowed down. The droplets generated in the large droplet generation unit 12 will catch up with and move downstream together with the positive droplet. The two adjacent droplets will not spontaneously merge under the action of surface tension.

[0035] In some embodiments, the microfluidic chip 1 is made of plastic, colloid, or glass, etc., and the present invention does not limit this.

[0036] See Figure 3-5 The present invention also relates to a microfluidic device, which includes a microfluidic chip 1 of any of the above schemes, and further includes a sample injection unit 2, a detection unit 3 and a dispensing unit 4; the sample injection unit 2 generally uses a high-precision pump as a power source, such as an injection pump, a peristaltic pump, a plunger pump, etc., preferably an injection pump.

[0037] In some embodiments, the detection unit 3 is located at the junction of the sorting pipe 15, the fusion pipe 132, and the negative droplet pipe 14. In this embodiment, the detection unit 3 can be one or more combinations of fluorescence detection, optical density detection, Raman detection, infrared detection, scattered light detection, impedance detection, or image recognition devices. The detection unit 3 is a module and can be configured according to different needs. Droplets that are detected as positive enter the fusion pipe 132 under the action of the sorting electrode 16, while negative droplets enter the negative droplet pipe 14.

[0038] like Figure 4-5As shown, the distribution unit 4 includes a pipe support 48, an X-axis guide rail 42, an X-axis motor 41, an X-axis slider 43, a Y-axis guide rail 45, a Y-axis motor 44, a Y-axis slider 46, and a collection container support 47. The Y-axis guide rail 45 is fixedly connected to the X-axis slider 43, and the collection container support 47 is fixedly connected to the Y-axis slider 46. The X-axis motor 41 drives the X-axis slider 43 to move along the X-axis guide rail 42, thereby moving the Y-axis guide rail 45. The Y-axis motor 44 drives the Y-axis slider 46 to move along the Y-axis guide rail 45, thereby moving the collection container support 47. This is achieved through the X-axis motor 41 and the Y-axis motor 44. The end of the sorting pipe 15 is connected to the pipe support 48. A collection container, such as a 24-well plate, a 96-well plate, an agar plate, or other common biological consumables, is fixedly placed on the collection container support 47. The microfluidic device also includes a droplet recovery mechanism, which includes a swing arm 51, a swing arm motor 50 that controls the movement of the swing arm 51, and a waste liquid recovery container 49 set on the swing arm 51. When it is necessary to collect the target droplet, the swing arm 51 is controlled to move the waste liquid recovery container away from the end outlet of the sorting pipe 15. The motor and guide rail are controlled to move the collection container, and the target droplet falls to the corresponding position of the collection container below.

[0039] In some cases, when no positive droplets are sorted into the fusion pipe 132, the large droplet generation unit 12 continues to generate large droplets. These large droplets are not the target droplets and need to be collected and processed. When the large droplets reach the end outlet of the sorting pipe 15, the waste liquid recovery container 49 is positioned directly opposite the end outlet of the sorting pipe 15, and the large droplets are collected by the waste liquid recovery mechanism.

[0040] This invention also provides a single-droplet printing method based on a microfluidic device, comprising the following steps: S1: Injecting a sample into a microfluidic chip 1 through a sample introduction unit 2, the oil phase and droplets are separated into small droplets by a small droplet sorting unit 11 and move downstream, wherein the volume of a single small droplet is 10 pL-100 nL (1×10⁻⁶). -5 mm 3 -1×10 -1 mm 3 Simultaneously, the oil phase and culture medium or reagents are distributed into large droplets that move downstream through the large droplet generation unit 12, with each large droplet having a volume of 100 nL-100 μL (1 × 10⁻⁶). -1 mm 3 -1×10 2 mm 3 );

[0041] S2: Drive the small droplets to flow through the detection unit 3. When a positive droplet is detected, control the sorting electrode 16 to make the positive droplet enter the fusion channel 132 under the action of dielectric force. When a negative droplet is detected, control it to flow to the negative droplet channel 14. At the same time, continuously drive the large droplet to move downstream.

[0042] S3: When an adjacent positive small droplet and a large droplet flow through the fusion electrode 131, they fuse into a new target droplet under the action of the electric field.

[0043] S4: Distribution unit 4 distributes the fused positive target droplets and collects and processes non-target droplets.

[0044] This method innovatively combines droplet microfluidic sorting and droplet fusion technology. Positive droplets are sorted by the small droplet sorting unit 11, and large droplets containing culture medium or reagents are generated by the large droplet generation unit 12. The inner diameter of the fusion channel 132 is widened to reduce the flow rate, causing the target positive droplet and the large droplet to collide. Then, an electric field is applied by the set AC electrode to change the surface tension of the target droplet and the reagent droplet, so that they fuse, thereby amplifying the small droplet into a large droplet. By manipulating the large droplet generated by fusion, it is convenient to manipulate the droplets, improve the activity of cells in the target droplet, reduce the loss of the target droplet, and ensure the steady state of the microfluidic device.

[0045] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A microfluidic chip, characterized in that, It includes a small droplet sorting unit, a large droplet generation unit, and a fusion unit. The small droplet sorting unit includes a first oil phase inlet, a first oil phase pipe, a first droplet inlet, a first droplet pipe, a sorting pipe, and a sorting electrode. The first oil phase pipe, the first droplet pipe, and the sorting pipe are connected. The oil phase enters the first oil phase pipe through the first oil phase inlet, and the droplets enter the first droplet pipe through the first droplet inlet. The oil phase and droplets flow through the connection between the first oil phase pipe and the first droplet pipe, forming spaced droplets that move downstream. The large droplet generation unit includes a second oil phase inlet, a second oil phase pipe, a first aqueous phase inlet, a first aqueous phase pipe, and a second droplet pipe. The oil phase enters the second oil phase pipe from the second oil phase inlet, and the culture medium or reagent enters the first aqueous phase pipe from the first aqueous phase inlet. The oil phase and the culture medium or reagent flow through the connection between the second oil phase pipe and the first aqueous phase pipe, forming spaced droplets that move downstream. The fusion unit includes a negative droplet channel, a fusion channel, and a fusion electrode. The sorting channel, the negative droplet channel, and the fusion channel are connected. The sorting electrode is disposed at the connection point between the negative droplet channel, the fusion channel, and the sorting channel.

2. A microfluidic chip according to claim 1, characterized in that, The first oil phase pipeline splits into two branches from the first oil phase inlet, namely the first oil phase pipeline a and the first oil phase pipeline b. The first oil phase pipeline a, the first oil phase pipeline b and the sorting pipeline are connected in a cross shape.

3. A microfluidic chip according to claim 1, characterized in that, The cross-sectional area of ​​the sorting pipe is 4×10 -4 mm 2 -4×10 -2 mm 2 The cross-sectional area of ​​the second droplet channel is 4 × 10⁻⁶. -2 mm 2 -1mm 2 The cross-sectional area of ​​the fusion pipe is 4×10 -2 mm 2 -1mm 2 .

4. A microfluidic chip according to claim 1, characterized in that, The microfluidic chip is made of one or more of the following materials: plastic, colloid, or glass.

5. A microfluidic device, characterized in that, Includes a microfluidic chip as described in any one of claims 1-4.

6. A microfluidic device according to claim 5, characterized in that, It includes a sample injection unit, a detection unit, and a dispensing unit. The sample injection unit is connected to the first oil phase injection port, the first droplet injection port, the second oil phase injection port, and the first aqueous phase injection port, respectively. The detection unit is located at the connection of the sorting pipe, the fusion pipe, and the negative droplet pipe.

7. A microfluidic device according to claim 6, characterized in that, The detection unit is one or more of the following: fluorescence detection, optical density detection, Raman detection, infrared detection, scattered light detection, impedance detection, or image recognition device.

8. A microfluidic device according to claim 6, characterized in that, The distribution unit includes a pipe support, an X-axis guide rail, an X-axis motor, an X-axis slider, a Y-axis guide rail, a Y-axis motor, a Y-axis slider, and a collection container support. The X-axis motor drives the X-axis slider to move along the X-axis guide rail, the Y-axis motor drives the Y-axis slider to move along the Y-axis guide rail, the Y-axis guide rail is fixedly connected to the X-axis slider, and the collection container support is fixedly connected to the Y-axis slider.

9. A microfluidic device according to claim 8, characterized in that, The distribution unit further includes a droplet recovery mechanism, which includes a swing arm, a swing arm motor for controlling the movement of the swing arm, and a waste liquid recovery container mounted on the swing arm.

10. A method for distributing droplets, characterized in that, The application of the microfluidic device according to any one of claims 5-9 includes the following steps: S1: Samples are introduced into the microfluidic chip through the sample introduction unit. The oil phase and droplets are separated into small droplets by the droplet sorting unit and move downstream. The volume of each small droplet is 10 pL-100 nL (1×10⁻⁶). -5 mm 3 -1×10 -1 mm 3 Simultaneously, the oil phase and culture medium or reagents form spaced large droplets that move downstream through the large droplet generation unit, with each large droplet having a volume of 100 nL-100 μL (1 × 10⁻⁶). -1 mm 3 -1×10 2 mm 3 ); S2: Drive the small droplets through the detection unit. When a positive droplet is detected, control the sorting electrode to make the positive droplet enter the fusion channel under the action of dielectric force. When a negative droplet is detected, control it to flow to the negative droplet channel. At the same time, continuously drive the large droplet to move downstream. S3: When an adjacent positive small droplet and a large droplet flow through the fusion electrode, they fuse into a new target droplet under the action of the electric field. S4: The distribution unit distributes the fused positive target droplets and collects and processes the non-target droplets.

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