Integrated droplet microfluidic chip

Abstract

The utility model relates to micro -fluidic technique field discloses an integrated droplet micro -fluidic chip, including base plate, is provided with continuous phase channel unit and dispersed phase channel unit on the base plate, and continuous phase channel unit includes linear main channel, and linear main channel intercommunication is provided with a plurality of main split channel, dispersed phase channel unit includes branch channel, and branch channel intercommunication is provided with a plurality of linear type branch split channel, and a plurality of linear type branch split channel and a plurality of main split channel intercommunication place are provided with droplet control structure respectively, and dispersed phase fluid and continuous phase fluid form droplet at droplet control structure. Due to the difference of viscosity and interfacial tension of continuous phase fluid and dispersed phase fluid, under the action of continuous phase fluid shear force, dispersed phase fluid will be cut by continuous phase fluid, thereby forming droplet, by controlling the same distance of dispersed phase fluid from inlet to each droplet control structure, thereby realizing high throughput and single dispersibility good microsphere preparation.

Description

Technical Field

[0001] This utility model relates to the field of microfluidics, specifically an integrated droplet microfluidic chip. Background Technology

[0002] Microfluidics is the science and technology of manipulating nanoliter to picoliter fluids within micrometer-scale channels (10µm~500µm). With advantages such as laminar flow dominance, high specific surface area, fast heat / mass transfer, and low reagent consumption, it has been applied in fields such as chemical synthesis, bioanalysis, and materials preparation. Droplet microfluidics is a subset of microfluidics, utilizing two immiscible fluids (oil / water or gas / liquid) to generate monodisperse droplets within microchannels. Each droplet acts as an independent microreactor, enabling a closed, parallel, and automated process of "sample / reagent encapsulation-mixing-reaction-detection." Precise control of multiphase flow within micrometer-scale channels allows for the continuous generation of monodisperse droplets; after solidification, the droplets transform into microspheres, achieving the preparation of monodisperse microspheres with controllable particle size.

[0003] However, traditional microfluidic chips have low throughput, making it difficult to scale up to industrial scale. Integrated chips employ a fluid distribution network with multiple droplet generation units connected in parallel, where each of the two phases of the fluid is driven by a single pump. The mainstream scaling-up approach is to increase parallel flow channels, with distribution structures including parallel, bifurcation, and annular. With parallel integration, as the number of channels increases, processing errors accumulate, flow distribution differences increase, and the monodispersity of the microspheres is poor. Bifurcation integration, due to linewidth deviations or local blockages, causes variations in flow resistance in each branch, resulting in uneven liquid distribution and decreased monodispersity. Annular integration arranges droplet generation units symmetrically along the circumference, with each unit having the same distance from the center, resulting in high flow consistency; however, as the number of channels increases, the chip area utilization decreases.

[0004] Existing microfluidic droplet generators, by arranging hundreds to thousands of droplet units in parallel, can achieve high-throughput preparation of monodisperse droplets in low-viscosity systems. However, droplet breakage depends on the balance between interfacial tension and viscous shear; as the viscosity of the dispersed phase increases, the ability of interfacial tension to regulate breakage behavior weakens, leading to a wider droplet size distribution, or even the inability to achieve stable breakage. Therefore, they are only suitable for droplets in low-viscosity systems. Utility Model Content

[0005] The purpose of this invention is to provide an integrated droplet microfluidic chip that effectively solves the technical problems of low throughput of traditional microfluidic chips and poor monodispersity of microspheres prepared by channel integration. At the same time, it provides an integrated droplet microfluidic chip that can produce microspheres with uniform size and high throughput.

[0006] The technical solution of this utility model is: An integrated droplet microfluidic chip includes a substrate, wherein a dispersed phase channel unit is disposed above the substrate and a continuous phase channel unit is disposed below the substrate. The continuous phase channel unit includes a straight main channel arranged in the transverse direction, and several main split channels are connected in the longitudinal direction on the straight main channel. The lengths of the several main split channels are different and they are distributed in a stepped manner. The dispersed phase channel unit includes a branch channel arranged laterally, and a plurality of straight branch split channels are arranged longitudinally along the branch channel. The lengths of the plurality of straight branch split channels are different; the plurality of straight branch split channels are connected to the plurality of main split channels. Several droplet control structures are respectively disposed at the junctions of several linear branch channels and several main branch channels; the dispersed phase fluid and the continuous phase fluid form droplets at the droplet control structures, and the dispersed phase fluid travels the same distance to each droplet control structure.

[0007] In a preferred embodiment, the dispersed phase channel unit further includes a dispersed phase inlet disposed on the branch channel, and the dispersed phase inlet has the same path to each droplet control structure.

[0008] In a preferred embodiment, the number of linear branch splitting channels is 2n, the number of main splitting channels is 2n+2, and the linear branch splitting channels and main splitting channels are symmetrically distributed on both sides of the dispersed phase inlet.

[0009] In a preferred embodiment, a linear branch channel is provided to connect two adjacent main branch channels.

[0010] In a preferred embodiment, the droplet control structure is a flow focusing structure used to break up the dispersed phase fluid and form droplets.

[0011] In a preferred embodiment, the substrate is further provided with a droplet generation unit, which includes a plurality of droplet generation channels, each of which is connected to a droplet control structure at a corresponding position.

[0012] In a preferred embodiment, the droplet generation unit further includes a plurality of collection ports, which are respectively disposed at the outlets of the plurality of droplet generation channels.

[0013] In a preferred embodiment, the dispersed phase channel unit further includes a dispersed phase flow channel, which is connected to the branch channel, and the dispersed phase inlet is located at the inlet of the dispersed phase flow channel.

[0014] In a preferred embodiment, the continuous phase channel unit further includes a continuous phase flow channel and a continuous phase inlet. The continuous phase flow channel is connected to the straight main channel, and the continuous phase inlet is located at the inlet of the continuous phase flow channel.

[0015] Compared with the prior art, the beneficial effects of this utility model are: This invention provides an integrated droplet microfluidic chip, comprising a substrate, a dispersed phase channel unit disposed above the substrate, and a continuous phase channel unit disposed below the substrate; the continuous phase channel unit includes a horizontally arranged linear main channel, and a plurality of main split channels connected longitudinally along the linear main channel, the plurality of main split channels having different lengths and being distributed in a stepped manner; the dispersed phase channel unit includes horizontally arranged branch channels, and a plurality of linear branch split channels connected longitudinally along the branch channels, the plurality of linear branch split channels having different lengths; the plurality of linear branch split channels are correspondingly connected to the plurality of main split channels; a plurality of droplet control structures are respectively disposed at the connection points of the plurality of linear branch split channels and the plurality of main split channels; the dispersed phase fluid and the continuous phase fluid form droplets at the droplet control structures, and the dispersed phase fluid travels the same distance to each droplet control structure.

[0016] In this invention, a droplet control structure is set at the connection between the linear branch splitting channel and the corresponding main splitting channel. Due to the difference in viscosity and interfacial tension between the continuous phase fluid and the dispersed phase fluid, and under the action of the shear force of the continuous phase fluid, the dispersed phase fluid is sheared by the continuous phase fluid, thereby forming droplets. By controlling the dispersed phase fluid to travel the same distance from the inlet to each droplet control structure, the uniformity of the generated droplet size is ensured. By setting multiple droplet control structures, the droplet yield is increased, thereby achieving the technical effect of high-throughput preparation of microspheres with good monodispersity. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an integrated droplet microfluidic chip according to the present invention.

[0018] Explanation of reference numerals in the attached figures: 1-1. Straight main channel; 1-2. Main split channel; 1-3. Continuous phase flow channel; 2-1. Branch channel; 2-2. Straight branch split channel; 2-3. Dispersed phase flow channel; 3-1. Droplet generation channel; 4. Collection port; 5. Droplet control structure; 6. Dispersed phase inlet; 7. Continuous phase inlet. Detailed Implementation

[0019] The following is combined with Figure 1The specific embodiments of this utility model will be described in detail below. In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model 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, and therefore should not be construed as a limitation of this utility model.

[0020] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of a utility model, unless otherwise stated, "a plurality of" means two or more.

[0021] Example like Figure 1 As shown, this embodiment of the present invention provides an integrated droplet microfluidic chip, including a substrate, wherein a dispersed phase channel unit is disposed above the substrate and a continuous phase channel unit is disposed below the substrate.

[0022] The continuous phase channel unit includes a straight main channel 1-1 arranged laterally, and several main split channels 1-2 connected longitudinally on the straight main channel 1-1. The lengths of the main split channels 1-2 are different and they are distributed in a stepped manner. The continuous phase fluid used in this invention is liquid paraffin + 5% Span 80. The continuous phase fluid is diverted to the several main split channels 1-2 through the straight main channel 1-1.

[0023] The dispersed phase channel unit includes a branch channel 2-1 arranged laterally, and a plurality of straight branch-split channels 2-2 connected longitudinally along the branch channel 2-1. The lengths of the branch-split channels are not uniform. The dispersed phase fluid used in this invention is water. The dispersed phase fluid is diverted through the branch channel 2-1 into the plurality of straight branch-split channels 2-2. The plurality of straight branch-split channels 2-2 are connected to the plurality of main split channels 1-2. The continuous phase fluid and the dispersed phase fluid meet at the connection between the branch-split channel 2-2 and the main split channel 1-2, forming water-in-oil droplets.

[0024] A plurality of droplet control structures 5 are respectively disposed at the junctions of the plurality of linear branch channels 2-2 and the plurality of main branch channels 1-2; the dispersed phase fluid and the continuous phase fluid form droplets at the droplet control structures 5, and the dispersed phase fluid travels the same distance to each droplet control structure 5.

[0025] To further ensure that the path of the dispersed phase fluid to each droplet control structure 5 is the same, the dispersed phase channel unit also includes a dispersed phase inlet 6, which is disposed on the branch channel 2-1. The path of the dispersed phase inlet 6 to each droplet control structure 5 is the same. The dispersed phase fluid water enters the branch channel 2-1 through the dispersed phase inlet 6, and then reaches the droplet control structure 5 through several branch split channels 2-2.

[0026] To ensure sufficient contact between the continuous phase fluid and the dispersed phase fluid to form droplets, the number of branch splitting channels 2-2 is 2n, and the number of main splitting channels 1-2 is 2n+2. The straight branch splitting channels 2-2 and the main splitting channels 1-2 are symmetrically distributed on both sides of the dispersed phase inlet 6. One straight branch splitting channel 2-2 is connected between the two main splitting channels, thereby ensuring sufficient contact between the continuous phase fluid liquid paraffin + 5% Span 80 passing through the two main splitting channels 1-2 and the dispersed phase fluid water passing through the one straight branch splitting channel 2-2 to form droplets.

[0027] In order to shear the dispersed phase fluid to form droplets, the droplet control structure 5 is a flow focusing structure used to break the dispersed phase fluid and form droplets.

[0028] In order to collect the droplets formed by the droplet control structure 5 and further solidify the microspheres, a droplet generation unit is also provided on the substrate. The droplet generation unit includes several droplet generation channels 3-1 and several collection ports 4. The droplet generation channels 3-1 are respectively connected to the droplet control structure 5 at the corresponding positions, and each droplet generation channel 3-1 has a corresponding collection port 4 at its outlet.

[0029] To guide the dispersed phase fluid and the continuous phase fluid to the branch channel 2-1 and the straight main channel 1-1 respectively, the dispersed phase channel unit further includes a dispersed phase flow channel 2-3, which is connected to the branch channel 2-1, and the dispersed phase inlet 6 is located at the inlet of the dispersed phase flow channel 2-3. The continuous phase channel unit further includes a continuous phase flow channel 1-3 and a continuous phase inlet 7, the continuous phase flow channel 1-3 being connected to the straight main channel 1-1, and the continuous phase inlet 7 being located at the inlet of the continuous phase flow channel 1-3.

[0030] In use, the continuous phase fluid (liquid paraffin + 5% Span 80 by mass) is injected into the linear main channel 1-1, while the dispersed phase fluid (water) is injected into the branch channel 2-1. The continuous phase fluid is distributed to all main split channels 1-2 through the linear main channel 1-1, and the dispersed phase fluid is distributed to all linear branch split channels 2-2 through the branch channel 2-1. The continuous and dispersed phase fluids come into contact through one linear branch split channel 2-2 and the corresponding two main split channels 1-2. Due to the difference in viscosity and interfacial tension between the continuous and dispersed phase solutions, and the continuous phase fluid... Under the shear force of the continuous phase fluid, the dispersed phase fluid is sheared by the continuous phase fluid, thus forming droplets. The droplets enter a droplet generation channel 3-1 at the junction of the linear branch channel 2-2 and the main branch channel 1-2. The droplets flow within the corresponding droplet generation channel 3-1 and finally enter the corresponding collection port 4 connected to the droplet generation channel 3-1. Since the dispersed phase fluid travels the same distance from the dispersed phase inlet 6 to each droplet control structure 5, the generated droplets are of uniform size, resulting in uniformly sized droplets at multiple collection ports 4. The droplets are collected in the collection ports 4. Subsequently, by replacing water with other dispersed phase solutions and using the droplets as templates, microspheres can be prepared after solidification.

[0031] The above-disclosed embodiments are merely preferred embodiments of the present utility model. However, the embodiments of the present utility model are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present utility model.

Claims

1. An integrated droplet microfluidic chip, comprising a substrate, characterized in that, A dispersed phase channel unit is disposed above the substrate, and a continuous phase channel unit is disposed below the substrate. The continuous phase channel unit includes a straight main channel (1-1) arranged in the transverse direction, and several main split channels (1-2) arranged in the longitudinal direction on the straight main channel (1-1). The lengths of the several main split channels (1-2) are different and they are distributed in a stepped manner. The dispersed phase channel unit includes a horizontally arranged branch channel (2-1), and a plurality of straight branch split channels (2-2) are arranged longitudinally on the branch channel (2-1). The lengths of the plurality of straight branch split channels (2-2) are different; the plurality of straight branch split channels (2-2) are connected to the plurality of main split channels (1-2). Several droplet control structures (5) are respectively disposed at the connection between several linear branch channels (2-2) and several main branch channels (1-2); the dispersed phase fluid and the continuous phase fluid form droplets at the droplet control structure (5), and the dispersed phase fluid travels the same distance to each droplet control structure (5).

2. The integrated droplet microfluidic chip according to claim 1, characterized in that, The dispersed phase channel unit also includes a dispersed phase inlet (6), which is disposed on the branch channel (2-1), and the dispersed phase inlet (6) has the same path to each droplet control structure (5).

3. The integrated droplet microfluidic chip according to claim 2, characterized in that, The number of linear branch splitting channels (2-2) is 2n, and the number of main splitting channels (1-2) is 2n+2. The linear branch splitting channels (2-2) and the main splitting channels (1-2) are symmetrically distributed on both sides of the dispersed phase inlet (6).

4. The integrated droplet microfluidic chip according to claim 3, characterized in that, A linear branch branch channel (2-2) is set up to connect two adjacent main branch channels (1-2).

5. The integrated droplet microfluidic chip according to claim 1, characterized in that, The droplet control structure (5) is a flow focusing structure used to break up the dispersed phase fluid and form droplets.

6. The integrated droplet microfluidic chip according to claim 1, characterized in that, The substrate is also provided with a droplet generation unit, which includes a plurality of droplet generation channels (3-1), which are respectively connected to the droplet control structure (5) at the corresponding position.

7. The integrated droplet microfluidic chip according to claim 6, characterized in that, The droplet generation unit also includes several collection ports (4), which are respectively disposed at the outlets of several droplet generation channels (3-1).

8. The integrated droplet microfluidic chip according to claim 2, characterized in that, The dispersed phase channel unit further includes a dispersed phase flow channel (2-3), which is connected to the branch channel (2-1), and the dispersed phase inlet (6) is located at the inlet of the dispersed phase flow channel (2-3).

9. The integrated droplet microfluidic chip according to claim 1, characterized in that, The continuous phase channel unit further includes a continuous phase flow channel (1-3) and a continuous phase inlet (7). The continuous phase flow channel (1-3) is connected to the straight main channel (1-1), and the continuous phase inlet (7) is located at the inlet of the continuous phase flow channel (1-3).

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