A device for preparing core-shell hydrogel microspheres

Abstract

The present application relates to a kind of core-shell hydrogel microsphere preparation device.The core-shell hydrogel microsphere preparation device includes microfluidic chip and hydrophobic connecting pipe, the microfluidic chip is equipped with core phase flow channel, shell phase flow channel, water same axis flow channel, oil phase flow channel, ball forming cavity and outlet flow channel, the end of the core phase flow channel and the shell phase flow channel meet, the meeting point is connected with the first end of the water same axis flow channel, the water same axis flow channel and the end of the oil phase flow channel meet in the ball forming cavity, the ball forming cavity is communicated with the first end of the outlet flow channel, the inner diameter of the ball forming cavity is 0.2~2 mm, the inner diameter of the outlet flow channel is 0.4~2 mm, the outer diameter of the hydrophobic connecting pipe is matched with the inner diameter of the outlet flow channel, the inner diameter of the hydrophobic connecting pipe is less than or equal to the inner diameter of the ball forming cavity, one end of the hydrophobic connecting pipe is inserted into the outlet flow channel.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microfluidic technology, and particularly relates to a device for preparing core-shell hydrogel microspheres. BACKGROUND

[0002] Hydrogel is a kind of polymer material with three-dimensional network structure, which has been widely used in the fields of biomedical, sensors and soft robots. Due to its controllable mechanical properties, high porosity and similarity to the natural extracellular matrix, hydrogel has shown great value in cell culture, tissue engineering, drug release and delivery. However, traditional bulk hydrogel has shown problems such as limited material exchange, mutual restriction between injectability and mechanical strength, etc. when used in various applications. Hydrogel microspheres, also known as microgels, have shown superior performance to bulk hydrogels in many aspects, showing great application potential.

[0003] Generally, the preparation of hydrogel microspheres mainly includes two steps, i.e. generating hydrogel droplets from continuous aqueous phase, and solidifying the droplets to form microspheres through different cross-linking strategies. In recent years, researchers have developed various technologies to manufacture hydrogel microspheres, such as emulsification method, photolithographic template method, electrohydrodynamic spraying method, mechanical breaking method, etc. However, these technologies have obvious shortcomings, for example, emulsification method, electrohydrodynamic spraying method, etc. can only generate polydisperse microspheres; although photolithographic template method can produce microspheres with uniform size, it is difficult to popularize due to the need for expensive equipment and the inability to achieve large-scale production.

[0004] With the development of droplet microfluidic technology, the hydrogel microsphere preparation method based on microfluidic chip has shown its unique advantages. This method realizes the high-throughput preparation of monodisperse hydrogel microspheres, and at the same time, benefiting from the high customization ability of microfluidic chip, the hydrogel microsphere preparation method based on microfluidic chip can stably prepare microspheres with various heterogeneous structures, such as core-shell microspheres, multi-compartment microspheres, etc. However, the preparation of hydrogel microspheres based on microfluidic chip is often affected by factors such as the viscosity and flow rate of the liquid, especially when the number of aqueous phases increases to construct heterogeneous microspheres. This influence makes the prepared hydrogel microspheres only be collected uniformly in a container, and then transferred to a multi-well plate or other culture vessels by equipment. For hydrogel microspheres with sizes in millimeter or micrometer level, it is difficult to efficiently and accurately transfer each one to the final application environment (such as multi-well plate, specific culture vessel). Therefore, in the current operation, the hydrogel microspheres can only be used together with the dispersion medium (usually water or oil phase) in the form of suspension volume as the unit of measurement and use. This rough operation mode not only cannot accurately control the actual number of microspheres used, but also causes a large waste of hydrogel microspheres.

[0005] To solve the problem of quantitative taking of small-diameter hydrogel microspheres, some enterprises have developed equipment based on suspension distribution. These devices usually rely on image recognition technology to count and release microspheres. However, the actual application effect of existing devices is not ideal, and there is a problem of large error in the number of released microspheres, and the precision is difficult to meet the application scenarios that require accurate control of the number of microspheres (such as single-cell encapsulation analysis, high-precision drug delivery dose control, etc.).

[0006] In summary, the current process for preparing hydrogel microspheres based on microfluidic technology is limited by parameter sensitivity, resulting in the collection of microspheres in a unified container, and it is difficult to achieve precise transfer and metering due to the small size of the microspheres. The quantitative solution provided by existing suspension distribution equipment has poor precision. These problems seriously limit the wide application value of this technology, especially hindering its promotion in advanced application scenarios that require high-precision microsphere number control and individualized operation (such as high-throughput screening, precise cell culture, personalized medicine). Therefore, it is urgent to develop a technical solution that can effectively solve the problems of precise metering, transfer, and distribution of hydrogel microspheres. SUMMARY

[0007] The present application aims to disclose a kind of core-shell hydrogel microsphere preparation device to solve one or more technical problems existing in the prior art, provide at least one beneficial choice or create conditions.

[0008] The first aspect of the present application is to provide a core-shell hydrogel microsphere preparation device.

[0009] The core-shell hydrogel microsphere preparation device comprises a microfluidic chip and a hydrophobic connecting tube, the microfluidic chip is provided with a core phase flow channel, a shell phase flow channel, a water same axis flow channel, an oil phase flow channel, a sphere forming cavity and an outlet flow channel, the ends of the core phase flow channel and the shell phase flow channel meet, the meeting point is connected with the first end of the water same axis flow channel, the water same axis flow channel and the end of the oil phase flow channel meet, the sphere forming cavity is communicated with the first end of the outlet flow channel, the inner diameter of the sphere forming cavity is 0.2-2 mm, the inner diameter of the outlet flow channel is 0.4-2 mm, the outer diameter of the hydrophobic connecting tube is matched with the inner diameter of the outlet flow channel, the inner diameter of the hydrophobic connecting tube is less than or equal to the inner diameter of the sphere forming cavity, and one end of the hydrophobic connecting tube is inserted into the outlet flow channel.

[0010] The microfluidic chip is provided with the converging core phase flow channel and the shell phase flow channel, so that the shell phase fluid wraps the core phase fluid flowing in the water coaxial flow channel. Then the coaxial fluid in the water coaxial flow channel enters the sphere forming cavity filled with the oil phase fluid, and is intercepted by the oil phase fluid into a core-shell water phase droplet with a diameter of about 0.2-2 mm. In addition, since the inner diameter of the hydrophobic connecting pipe is less than or equal to the inner diameter of the sphere forming cavity, the oil phase fluid pushes the core-shell water phase droplet into the hydrophobic connecting pipe and forms an "oil phase-core-shell water phase-oil phase-core-shell water phase" alternating liquid segment state. The segment spacing of the alternating liquid segment in the hydrophobic connecting pipe is affected by the flow rates of the core phase fluid, the shell phase fluid and the oil phase fluid. When the feeding flow rates of the core phase flow channel, the shell phase flow channel and the oil phase flow channel are stable, the flow rate and spacing of the alternating liquid segment will also be stable and unchanged. Only the core-shell hydrogel microspheres can be obtained at the end of the hydrophobic connecting pipe by cross-linking and solidifying the core-shell water phase droplets in the hydrophobic connecting pipe, and the core-shell hydrogel microspheres are sent out at equal time intervals, so that the number of core-shell hydrogel microspheres can be accurately distributed and used in cooperation with automatic equipment.

[0011] In a further application embodiment, the microfluidic chip is composed of two layers, the upper layer and the lower layer, both of which are polydimethylsiloxane (PDMS) components. The cross sections of the fluid channels in the microfluidic chip are circular.

[0012] In a further application embodiment, the sphere forming cavity is cylindrical, the first end of which communicates with the oil phase flow channel, and the second end of which communicates with the outlet flow channel. The water coaxial flow channel communicates with the side wall of the sphere forming cavity. The water coaxial flow channel, the oil phase flow channel and the outlet flow channel constitute a T-shaped junction (T-Junction).

[0013] In a further application embodiment, the central axis of the core phase flow channel is on the same straight line as the central axis of the water coaxial flow channel. The shell phase flow channel has two branches, which are connected to the junction point from both sides. The core phase flow channel, the two shell phase flow channels and the water coaxial flow channel constitute a cross-shaped junction (Cross-Junction).

[0014] In a further application embodiment, the inner diameter of the core phase flow channel is 0.15-0.5 mm; the inner diameter of the shell phase flow channel is 0.15-0.5 mm; the inner diameter of the water coaxial flow channel is 0.2-0.7 mm, and the inner diameter of the water coaxial flow channel is greater than the inner diameter of the core phase flow channel and the core phase flow channel; the inner diameter of the oil phase flow channel is 0.4-2 mm.

[0015] In a further application embodiment, the first end of the core phase flow channel and the shell phase flow channel are both disc-shaped inlets with a diameter of 0.4-1.5 mm.

[0016] In a further application embodiment, the length of the ball forming cavity is the same as the inner diameter of the water co-axial flow channel, which is perpendicular to the ball forming cavity.

[0017] In a further application embodiment, the material of the hydrophobic connecting tube is selected from polytetrafluoroethylene (PTFE), soluble polytetrafluoroethylene (PFA), or ethylene-tetrafluoroethylene copolymer (ETFE).

[0018] In a further application embodiment, the end of the hydrophobic connecting tube inserted into the port in the outlet flow channel is 0-0.2 mm from the end of the ball forming cavity.

[0019] Part of the core-shell water phase droplets need to be treated before being cross-linked and solidified, for example, when the shell phase fluid uses light cross-linking hydrogel materials such as methacrylated hyaluronic acid (HAMA) or methacrylated gelatin (GelMA), the core-shell hydrogel microsphere preparation device further includes a light source, and the hydrophobic connecting tube is a translucent or transparent member, and the light source irradiates the hydrophobic connecting tube. When the shell phase fluid uses low-temperature thermal cross-linking materials such as type I collagen hydrogel, Matrigel hydrogel, or decellularized extracellular matrix (dECM) hydrogel, the core-shell hydrogel microsphere preparation device further includes a heat source, and the heat source supplies heat to the hydrophobic connecting tube.

[0020] In a further application embodiment, the oil phase fluid is a volatile fluorinated oil that can be completely volatilized within a few seconds after being exposed to the air environment, so it does not affect the direct use of the core-shell hydrogel microspheres.

[0021] In a further application embodiment, the core-shell hydrogel microsphere preparation device further includes a dispensing liquid system:

[0022] A support plate is provided with a slide;

[0023] A moving unit includes a moving platform, an X-direction slide rail, and a Y-direction slide rail, the Y-direction slide rail is vertically arranged on the slide, the Y-direction slide rail can move in the Y-direction on the slide, the X-direction slide rail is vertically arranged on the Y-direction slide rail, the X-direction slide rail can move in the X-direction on the Y-direction slide rail, and the moving platform is fixed above the X-direction slide rail.

[0024] The end of the hydrophobic connecting pipe is fixed above the moving platform, a well plate for carrying the core-shell hydrogel microspheres is placed on the moving platform, and the end of the hydrophobic connecting pipe can be aligned with any one pore on the well plate through the moving unit. When the hydrophobic connecting pipe can stably interval out the material, by controlling the moving distance and interval of the moving unit, the same number of core-shell hydrogel microspheres can be accurately placed in each pore on the well plate.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] (1) The core-shell hydrogel microsphere preparation device provided by the present application has the advantages of easy operation, high reliability and repeatability, and low cost.

[0027] (2) The core-shell hydrogel microsphere preparation device has stable and controllable ball size, ball formation rate and microsphere spacing during the preparation of core-shell hydrogel microspheres. The core-shell hydrogel microspheres can be directly connected to the automatic spotting equipment after being discharged from the hydrophobic connecting pipe, realizing simple and stable construction of high-throughput core-shell hydrogel microsphere array, greatly reducing manual operation in the field of drug evaluation, and improving experimental efficiency and result reliability. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a perspective view of the microfluidic chip described in Example 1;

[0029] Figure 2 is an exploded view of the microfluidic chip described in Example 1;

[0030] Figure 3 is a top view of the microfluidic chip described in Example 1;

[0031] Figure 4 is a schematic diagram of the fluid flow direction of the microfluidic chip described in Example 1. DETAILED DESCRIPTION

[0032] In the description of the present application, if the first, second, etc. are described, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0033] The words "preferably", "more preferably", etc. in the present application mean that the embodiments of the present application can provide certain beneficial effects in certain cases. However, other embodiments can also be preferred in the same or other cases. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present application.

[0034] When a numerical range is disclosed herein, the range is to be construed as being continuous along the entire range, and inclusive of the minimum and maximum values of the range, as well as each integer within the range. Further, where a range is provided, it is intended to include every combination of the minimum and maximum values within the range. In other words, every possible subrange is incorporated within the scope of the range. Unless otherwise indicated, all ranges disclosed herein are to be construed as being inclusive of the endpoints.

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort fall within the scope of the present application.

[0036] The reagents, methods and devices used in the present application are conventional reagents, methods and devices in the technical field unless otherwise specified.

[0037] Example 1

[0038] A preparation process of a core-shell hydrogel microsphere includes:

[0039] (A) Microfluidic chip design: the microfluidic chip 1 is composed of an upper layer 2 and a lower layer 3, and both the upper layer and the lower layer are polydimethylsiloxane (PDMS) components with a thickness of 2 mm. The cross sections of the fluid channels in the microfluidic chip 1 are all circular. The fluid channels include a core phase flow channel 4 with an inner diameter of 0.15 mm, a shell phase flow channel 6 with an inner diameter of 0.15 mm, a water same axis flow channel 7 with an inner diameter of 0.2 mm, an oil phase flow channel 9 with an inner diameter of 0.4 mm, a sphere forming cavity 8 with an inner diameter and length of 0.2 mm, and an outlet flow channel 10 with an inner diameter of 0.4 mm. The first ends of the core phase flow channel 4 and the shell phase flow channel 6 are both disc-shaped inlets 5 with a diameter of 0.4 mm. The central axis of the core phase flow channel 4 is on the same straight line as the central axis of the water same axis flow channel 7, and the shell phase flow channel 6 has two branches respectively connected to the convergence point from both sides, and the core phase flow channel 4, the two shell phase flow channels 6 and the water same axis flow channel 7 form a cross-junction. The sphere forming cavity 8 is cylindrical, and the first end is connected to the oil phase flow channel 9, and the second end is connected to the outlet flow channel 10. The water same axis flow channel 7 is connected to the side wall of the sphere forming cavity 8, and the water same axis flow channel 7, the oil phase flow channel 9 and the outlet flow channel 10 form a T-junction.

[0040] (B) Hydrophobic connection tube design and assembly: The hydrophobic connection tube is made of translucent polytetrafluoroethylene (PTFE) with an outer diameter of 0.4 mm and an inner diameter of 0.2 mm. The first end of the tube is inserted into the outlet flow channel and directly connected to the end of the sphere-forming cavity.

[0041] (C) Preparation of core-shell water phase droplets: The shell phase fluid 11 is a GelMA solution containing a photoinitiator LAP, and the core phase fluid 12 converges with the shell phase fluid 11 at the water coaxial flow channel 7 to form a coaxial flow state into the sphere-forming cavity 8 filled with the oil phase fluid 14. Under the action of surface tension, the core-shell coated structure of the water phase 13 is initially formed and fills the sphere-forming cavity 8. The water phase 13 blocks the oil phase fluid 14 from entering the hydrophobic connection tube, and the flow-restricted oil phase fluid 14 shears the water phase 13 into core-shell water phase droplets 15 and pushes them into the hydrophobic connection tube. Since the inner diameters of the sphere-forming cavity 8 and the hydrophobic connection tube are both 0.2 mm, the oil phase fluid 14 and the core-shell water phase droplets 15 alternately form an "oil phase-core-shell water phase-oil phase-core-shell water phase" state.

[0042] (D) Solidification and collection: The core-shell water phase droplets 15 are irradiated by blue light with a wavelength of about 405 nm in the transparent hydrophobic connection tube, achieving cross-linking and solidification of the shell layer. Subsequently, it can be connected to a dispensing liquid system to construct a high-throughput array of core-shell hydrogel microspheres.

[0043] Example 2

[0044] A preparation process of core-shell hydrogel microspheres, comprising:

[0045] (A) Microfluidic chip design: The microfluidic chip is composed of two layers, the upper and lower layers are both polydimethylsiloxane (PDMS) components with a thickness of 3 mm. The fluid channels in the microfluidic chip are all circular in cross-section. The fluid channels include a core phase flow channel with an inner diameter of 0.2 mm, a shell phase flow channel with an inner diameter of 0.2 mm, a water coaxial flow channel with an inner diameter of 0.3 mm, an oil phase flow channel with an inner diameter of 0.5 mm, a sphere-forming cavity with an inner diameter of 0.4 mm and a length of 0.3 mm, and an outlet flow channel with an inner diameter of 0.5 mm. The central axis of the core phase flow channel is on the same straight line as the central axis of the water coaxial flow channel, and the shell phase flow channel has two branches that connect to the convergence point from both sides. The core phase flow channel, the two shell phase flow channels, and the water coaxial flow channel form a cross-junction. The sphere-forming cavity is cylindrical, with the first end connected to the oil phase flow channel and the second end connected to the outlet flow channel. The water coaxial flow channel is connected to the side wall of the sphere-forming cavity, and the water coaxial flow channel, the oil phase flow channel, and the outlet flow channel form a T-junction.

[0046] (B) Hydrophobic connection tube design and assembly: The hydrophobic connection tube is made of transparent and soluble polytetrafluoroethylene (PFA) with an outer diameter of 0.5 mm and an inner diameter of 0.4 mm. The first end of the tube is inserted into the outlet flow channel at a distance of 0.05 mm from the end of the sphere-forming cavity.

[0047] (C) Preparation of core-shell water phase droplets: The shell phase fluid is a GelMA solution containing a photoinitiator LAP, and the core phase fluid is combined with the shell phase fluid at the water same axis flow channel to form a coaxial flow state into the sphere-forming cavity filled with the oil phase fluid. Under the action of surface tension, the core-shell water phase droplets are initially formed and filled into the sphere-forming cavity. The water phase hinders the oil phase fluid from entering the hydrophobic connection tube, and the flow-restricted oil phase fluid shears the water phase into core-shell water phase droplets and pushes them into the hydrophobic connection tube. Since the inner diameters of the sphere-forming cavity and the hydrophobic connection tube are both 0.4 mm, the oil phase fluid and the core-shell water phase droplets alternately form an "oil phase-core-shell water phase-oil phase-core-shell water phase" state.

[0048] (D) Solidification and collection: The core-shell water phase droplets in the transparent hydrophobic connection tube are irradiated by blue light with a wavelength of about 405 nm to achieve cross-linking and solidification of the shell layer. Subsequently, a high-throughput array of core-shell hydrogel microspheres can be constructed by connecting to a dispensing liquid system.

[0049] Example 3

[0050] A preparation process of core-shell hydrogel microspheres, comprising:

[0051] (A) Microfluidic chip design: The microfluidic chip is composed of two layers, the upper and lower layers are both polydimethylsiloxane (PDMS) components with a thickness of 4 mm. The fluid channels in the microfluidic chip are all circular in cross-section. The fluid channels include a core phase flow channel with an inner diameter of 0.3 mm, a shell phase flow channel with an inner diameter of 0.3 mm, a water same axis flow channel with an inner diameter of 0.5 mm, an oil phase flow channel with an inner diameter of 0.8 mm, a sphere-forming cavity with an inner diameter of 0.8 mm and a length of 0.5 mm, and an outlet flow channel with an inner diameter of 0.8 mm. The central axis of the core phase flow channel is on the same straight line as the central axis of the water same axis flow channel, and the shell phase flow channel has two branches that connect to the convergence point from both sides. The core phase flow channel, the two shell phase flow channels, and the water same axis flow channel form a cross-junction. The sphere-forming cavity is cylindrical in shape, with the first end connected to the oil phase flow channel and the last end connected to the outlet flow channel. The water same axis flow channel is connected to the side wall of the sphere-forming cavity, and the water same axis flow channel, the oil phase flow channel, and the outlet flow channel form a T-junction.

[0052] (B) Hydrophobic connection tube design and assembly: The hydrophobic connection tube is made of transparent PTFE with an outer diameter of 0.8 mm and an inner diameter of 0.6 mm. The first end of the tube is inserted into the outlet flow channel at a distance of 0.1 mm from the end of the sphere-forming cavity.

[0053] (C) Preparation of core-shell water phase droplets: The shell phase fluid is a HAMA solution containing a photoinitiator LAP, and the core phase fluid is combined with the shell phase fluid at the water coaxial flow channel to form a coaxial flow state into the sphere-forming cavity filled with the oil phase fluid. Under the action of surface tension, the core-shell water phase structure is initially formed and fills the sphere-forming cavity. The water phase hinders the oil phase fluid from entering the hydrophobic connection tube, and the flow-restricted oil phase fluid shears the water phase into core-shell water phase droplets and pushes them into the interior of the hydrophobic connection tube. Since the inner diameter of the hydrophobic connection tube is 0.6 mm, which is slightly narrower than the inner diameter of the sphere-forming cavity, the core-shell water phase droplets are squeezed into an elliptical shape. The oil phase fluid and the core-shell water phase droplets alternately form an "oil phase-core-shell water phase-oil phase-core-shell water phase" state.

[0054] (D) Solidification and collection: The core-shell water phase droplets in the transparent hydrophobic connection tube are irradiated by blue light with a wavelength of about 405 nm to achieve cross-linking and solidification of the shell layer, and subsequent connection with a dispensing liquid system to construct a high-throughput array of core-shell hydrogel microspheres.

[0055] Example 4

[0056] A preparation process of core-shell hydrogel microspheres, comprising:

[0057] (A) Microfluidic chip design: The microfluidic chip is composed of two layers, the upper and lower layers are both polydimethylsiloxane (PDMS) components with a thickness of 5 mm. The fluid channels in the microfluidic chip are all circular in cross-section. The fluid channels include a core phase flow channel with an inner diameter of 0.4 mm, a shell phase flow channel with an inner diameter of 0.4 mm, a water coaxial flow channel with an inner diameter of 0.6 mm, an oil phase flow channel with an inner diameter of 1.5 mm, a sphere-forming cavity with an inner diameter of 1.2 mm and a length of 0.6 mm, and an outlet flow channel with an inner diameter of 1.5 mm. The central axis of the core phase flow channel is on the same straight line as the central axis of the water coaxial flow channel, and the shell phase flow channel has two branches that are connected to the convergence point from both sides. The core phase flow channel, the two shell phase flow channels, and the water coaxial flow channel form a cross-junction. The sphere-forming cavity is cylindrical in shape, with the first end connected to the oil phase flow channel and the last end connected to the outlet flow channel. The water coaxial flow channel is connected to the side wall of the sphere-forming cavity, and the water coaxial flow channel, the oil phase flow channel, and the outlet flow channel form a T-junction.

[0058] (B) Hydrophobic connection tube design and assembly: The hydrophobic connection tube is made of transparent PTFE with an outer diameter of 1.5 mm and an inner diameter of 1.2 mm. The first end of the tube is inserted into the outlet flow channel at a distance of 0.15 mm from the end of the sphere-forming cavity.

[0059] (C) Preparation of core-shell water phase droplets: The shell phase fluid is a type I collagen hydrogel solution. The core phase fluid and the shell phase fluid meet at the water co-axial flow channel and enter the sphere-forming cavity filled with the oil phase fluid in a coaxial flow state. Under the action of surface tension, the core-shell water phase structure is initially formed and fills the sphere-forming cavity. The water phase hinders the oil phase fluid from entering the hydrophobic connection tube, and the flow-restricted oil phase fluid shears the water phase into core-shell water phase droplets and pushes them into the hydrophobic connection tube. Since the inner diameters of the sphere-forming cavity and the hydrophobic connection tube are both 1.2 mm, the oil phase fluid and the core-shell water phase droplets alternately form an "oil phase-core-shell water phase-oil phase-core-shell water phase" state.

[0060] (D) Solidification and collection: Heating the hydrophobic connection tube to an internal environment of about 37°C allows the type I collagen hydrogel in the shell layer to crosslink and solidify, thus enabling the collection of core-shell hydrogel microspheres at the outlet at the end of the hydrophobic connection tube.

[0061] Example 5

[0062] A preparation process of core-shell hydrogel microspheres, comprising:

[0063] (A) Microfluidic chip design: The microfluidic chip is composed of an upper layer and a lower layer, both of which are polydimethylsiloxane (PDMS) components with a thickness of 5 mm. The fluid channels in the microfluidic chip are all circular in cross-section. The fluid channels include a core phase flow channel with an inner diameter of 0.4 mm, a shell phase flow channel with an inner diameter of 0.4 mm, a water co-axial flow channel with an inner diameter of 0.6 mm, an oil phase flow channel with an inner diameter of 1.5 mm, a sphere-forming cavity with an inner diameter of 1.2 mm and a length of 0.6 mm, and an outlet flow channel with an inner diameter of 1.5 mm. The central axis of the core phase flow channel is on the same straight line as the central axis of the water co-axial flow channel. The shell phase flow channel has two branches that connect to the junction point from both sides. The core phase flow channel, the two shell phase flow channels, and the water co-axial flow channel form a cross-junction. The sphere-forming cavity is cylindrical in shape, with the first end connected to the oil phase flow channel and the last end connected to the outlet flow channel. The water co-axial flow channel is connected to the side wall of the sphere-forming cavity. The water co-axial flow channel, the oil phase flow channel, and the outlet flow channel form a T-junction.

[0064] (B) Hydrophobic connection tube design and assembly: The hydrophobic connection tube is made of transparent PTFE with an outer diameter of 1.5 mm and an inner diameter of 1.2 mm. The first end of the tube is inserted into the outlet flow channel at a distance of 0.15 mm from the end of the sphere-forming cavity.

[0065] (C) Preparation of core-shell water phase droplets: The shell phase fluid is a Matrigel hydrogel solution. The core phase fluid and the shell phase fluid meet at the water coaxial flow channel and enter the sphere-forming cavity filled with the oil phase fluid in a coaxial flow state. Under the action of surface tension, the core-shell water phase structure is initially formed and fills the sphere-forming cavity. The water phase hinders the oil phase fluid from entering the hydrophobic connection tube, and the flow-restricted oil phase fluid shears the water phase into core-shell water phase droplets and pushes them into the hydrophobic connection tube. Since the inner diameters of the sphere-forming cavity and the hydrophobic connection tube are both 1.2 mm, the oil phase fluid and the core-shell water phase droplets alternately form an "oil phase-core-shell water phase-oil phase-core-shell water phase" state.

[0066] (D) Solidification and collection: Heating the hydrophobic connection tube to an environment of about 37°C allows the Matrigel hydrogel in the shell layer to crosslink and solidify, and subsequent connection to a dispensing liquid system can construct a high-throughput core-shell hydrogel microsphere array.

[0067] Example 6

[0068] A preparation process of core-shell hydrogel microspheres, comprising:

[0069] (A) Microfluidic chip design: The microfluidic chip is composed of two layers, the upper and lower layers are both polydimethylsiloxane (PDMS) components with a thickness of 6 mm. The fluid channels in the microfluidic chip are all circular in cross-section. The fluid channels include a core phase flow channel with an inner diameter of 0.5 mm, a shell phase flow channel with an inner diameter of 0.5 mm, a water coaxial flow channel with an inner diameter of 0.7 mm, an oil phase flow channel with an inner diameter of 2 mm, a sphere-forming cavity with an inner diameter of 2 mm and a length of 0.7 mm, and an outlet flow channel with an inner diameter of 2 mm. The central axis of the core phase flow channel is on the same straight line as the central axis of the water coaxial flow channel. The shell phase flow channel has two branches that connect to the convergence point from both sides. The core phase flow channel, the two shell phase flow channels, and the water coaxial flow channel form a cross-junction. The sphere-forming cavity is cylindrical in shape, with the first end connected to the oil phase flow channel and the last end connected to the outlet flow channel. The water coaxial flow channel is connected to the side wall of the sphere-forming cavity. The water coaxial flow channel, the oil phase flow channel, and the outlet flow channel form a T-junction.

[0070] (B) Hydrophobic connecting tube design and assembly: The hydrophobic connecting tube is made of transparent PTFE, outer diameter 2 mm, inner diameter 1.8 mm, its first end is inserted into the outlet flow channel, 0.2 mm away from the end of the sphere-forming cavity.

[0071] (C) Preparation of core-shell water phase droplets: The shell phase fluid is Matrigel hydrogel solution, the core phase fluid and the shell phase fluid converge at the same axis flow channel to enter the sphere-forming cavity filled with oil phase fluid in a coaxial flow state, and under the action of surface tension, the core-shell coated structure of the water phase is preliminarily formed and fills the sphere-forming cavity. The water phase hinders the oil phase fluid from entering the hydrophobic connecting tube, and the flow blocked oil phase fluid shears the water phase into core-shell water phase droplets and pushes them into the inside of the hydrophobic connecting tube. Since the inner diameter of the hydrophobic connecting tube is 1.8 mm, which is slightly narrower than the inner diameter of the sphere-forming cavity, the core-shell water phase droplets are squeezed into an elliptical shape. The oil phase fluid and the core-shell water phase droplets alternately form an "oil phase-core-shell water phase-oil phase-core-shell water phase" state.

[0072] (D) Solidification and collection: heating the hydrophobic connecting tube to make its inside at an environment of about 37℃, allowing the Matrigel hydrogel of the shell layer to crosslink and solidify, and subsequently being able to be connected with a dispensing liquid system to construct a high-throughput core-shell hydrogel microsphere array.

[0073] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application.

Claims

1. A device for preparing core-shell hydrogel microspheres, characterized by, The microfluidic chip comprises a core phase flow channel, a shell phase flow channel, a water same axis flow channel, an oil phase flow channel, a sphere forming cavity and an outlet flow channel, the end of the core phase flow channel and the shell phase flow channel meet, the meeting point is connected with the head end of the water same axis flow channel, the water same axis flow channel and the end of the oil phase flow channel meet in the sphere forming cavity, the sphere forming cavity is communicated with the head end of the outlet flow channel, the inner diameter of the sphere forming cavity is 0.2-2 mm, the inner diameter of the outlet flow channel is 0.4-2 mm, the outer diameter of the hydrophobic connecting pipe is matched with the inner diameter of the outlet flow channel, the inner diameter of the hydrophobic connecting pipe is less than or equal to the inner diameter of the sphere forming cavity, and one end of the hydrophobic connecting pipe is inserted into the outlet flow channel.

2. The device for preparing core-shell hydrogel microspheres according to claim 1, wherein The sphere forming cavity is cylindrical, the head end is communicated with the oil phase flow channel, the tail end is communicated with the outlet flow channel, the water same axis flow channel is communicated with the side wall of the sphere forming cavity, and the water same axis flow channel, the oil phase flow channel and the outlet flow channel form a T-shaped meeting.

3. The apparatus for preparing core-shell hydrogel microspheres according to claim 1, characterized in that, The central axis of the core phase flow channel is on the same line with the central axis of the water same axis flow channel, the shell phase flow channel has two, which are connected to the meeting point from both sides, and the core phase flow channel, the two shell phase flow channels and the water same axis flow channel form a cross-shaped meeting.

4. The apparatus for preparing core-shell hydrogel microspheres according to claim 1, characterized in that, The inner diameter of the core phase flow channel is 0.15-0.5 mm, the inner diameter of the shell phase flow channel is 0.15-0.5 mm, the inner diameter of the water same axis flow channel is 0.2-0.7 mm, and the inner diameter of the water same axis flow channel is greater than the inner diameter of the core phase flow channel and the core phase flow channel, and the inner diameter of the oil phase flow channel is 0.4-2 mm.

5. The device for preparing core-shell hydrogel microspheres according to claim 4, wherein The length of the sphere forming cavity is the same as the inner diameter of the water same axis flow channel, and the water same axis flow channel is perpendicular to the sphere forming cavity.

6. The apparatus for preparing core-shell hydrogel microspheres according to claim 1, characterized in that, The material of the hydrophobic connecting pipe is selected from polytetrafluoroethylene, soluble polytetrafluoroethylene or ethylene-tetrafluoroethylene copolymer.

7. The apparatus for preparing core-shell hydrogel microspheres according to claim 1, characterized in that, The port of the hydrophobic connecting pipe inserted into the outlet flow channel is 0-0.2 mm away from the tail end of the sphere forming cavity.

8. The apparatus for preparing core-shell hydrogel microspheres according to any one of claims 1 to 7, characterized in that, Further comprising a light source, the hydrophobic connecting pipe is a translucent or transparent member, and the light source irradiates the hydrophobic connecting pipe.

9. The apparatus for preparing core-shell hydrogel microspheres according to any one of claims 1 to 7, characterized in that, Further comprising a heat source, the heat source supplies heat to the hydrophobic connecting pipe.

10. The apparatus for preparing core-shell hydrogel microspheres according to any one of claims 1 to 7, characterized in that, Further comprising a dispensing liquid system: A support plate, the support plate is provided with a slide; A moving unit, the moving unit comprises a moving platform, an X-direction slide rail and a Y-direction slide rail, the Y-direction slide rail is vertically arranged on the slide, the Y-direction slide rail can move in the Y-direction on the slide, the X-direction slide rail is vertically arranged on the Y-direction slide rail, the X-direction slide rail can move in the X-direction on the Y-direction slide rail, and the moving platform is fixed above the X-direction slide rail.

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