Core-shell hydrogel microsphere preparation device

Abstract

The invention relates to a device for preparing core-shell hydrogel microspheres. The core-shell hydrogel microsphere preparation device comprises a microfluidic chip and a hydrophobic connecting pipe, the microfluidic chip is internally provided with a nuclear phase flow channel, a shell phase flow channel, a water phase axial flow channel, an oil phase flow channel, a balling cavity and an outlet flow channel, the tail ends of the nuclear phase flow channel and the shell phase flow channel are converged, the converging point is connected with the head end of the water phase axial flow channel, and the shell phase flow channel is connected with the shell phase flow channel. The tail end of the water phase axial flow channel and the tail end of the oil phase flow channel intersect in the balling cavity, the balling cavity is communicated with the head end of the outlet flow channel, the inner diameter of the balling cavity is 0.2-2 mm, the inner diameter of the outlet flow channel is 0.4-2 mm, the outer diameter of the drainage connecting pipe is matched with the inner diameter of the outlet flow channel, and the drainage connecting pipe is communicated with the head end of the water phase axial flow channel and the head end of the oil phase flow channel. The inner diameter of the drainage connecting pipe is smaller than or equal to that of the balling cavity, and one end of the drainage connecting pipe is inserted into the outlet runner.

Description

Technical Field

[0001] The present invention relates to the field of microfluidic technology, in particular to a device for preparing core-shell hydrogel microspheres. Background Art

[0002] Hydrogels are polymer materials with a three-dimensional grid structure that have been widely used in fields such as biomedicine, sensors, and soft robotics. Given their controllable mechanical properties, high porosity, and similarity to the natural extracellular matrix, hydrogels have shown great value in cell culture, tissue engineering, and drug release and delivery. However, traditional block hydrogels have shown problems in various applications, such as limited material exchange and the mutual constraints between injectability and mechanical strength. Hydrogel microspheres, also known as microgels, have demonstrated superior performance to block hydrogels in many aspects, showing great application potential.

[0003] Typically, the preparation of hydrogel microspheres involves two main steps: generating hydrogel droplets from a continuous aqueous phase and solidifying the droplets to form microspheres through different cross-linking strategies. In recent years, researchers have developed a variety of techniques to produce hydrogel microspheres, such as emulsification, photolithography templates, electrohydrodynamic spraying, and mechanical disruption. However, most of these techniques have significant shortcomings. For example, emulsification and electrohydrodynamic spraying can only produce polydisperse microspheres. Although photolithography templates can produce microspheres of uniform size, they require expensive equipment and cannot be mass-produced, making them difficult to promote and use.

[0004] With the development of droplet microfluidics, microfluidic chip-based hydrogel microsphere preparation methods have demonstrated unique advantages. This method enables high-throughput preparation of monodisperse hydrogel microspheres. Furthermore, thanks to the highly customizable capabilities of microfluidic chips, microgel microsphere preparation methods can reliably produce a variety of heterogeneous microsphere structures, such as core-shell microspheres and multi-compartment microspheres. However, the preparation of hydrogel microspheres based on microfluidic chips is often susceptible to various factors, such as liquid viscosity and flow rate. This is particularly pronounced when the number of aqueous phases is increased to construct heterogeneous microsphere structures. This effect forces the prepared hydrogel microspheres to be collected in a single container and subsequently transferred to multiwell plates or other culture vessels. For hydrogel microspheres with millimeter or micrometer dimensions, efficient and precise transfer of each individual hydrogel microsphere to its final application environment (e.g., multiwell plates or specialized culture vessels) is difficult. Therefore, in current practices, hydrogel microspheres are measured and used only by suspension volume, along with their supporting dispersion medium (typically water or oil). This extensive operation mode not only fails to accurately control the actual number of microspheres used, but also causes a large amount of waste of hydrogel microspheres.

[0005] To address the quantitative dispensing of small-diameter hydrogel microspheres, some companies have developed suspension-based dispensing devices. These devices typically rely on image recognition technology to count and dispense microspheres. However, the practical application of existing devices is less than ideal, with large errors in the number of microspheres dispensed. Their accuracy is insufficient for applications requiring precise microsphere counts, such as single-cell encapsulation analysis and high-precision drug delivery dosage control.

[0006] In summary, the current microfluidics-based process for preparing hydrogel microspheres is limited by parameter sensitivity, resulting in the collection of microspheres in a single container. Furthermore, the microspheres' tiny size makes precise transfer and metering difficult. Existing suspension dispensing equipment also offers limited quantitative solutions. These issues severely limit the widespread application of this technology, particularly in advanced applications requiring high-precision microsphere number control and personalized manipulation (such as high-throughput screening, precision cell culture, and personalized medicine). Therefore, there is an urgent need to develop a technical solution that can effectively address the issues of precise metering, transfer, and distribution of hydrogel microspheres. Summary of the Invention

[0007] The purpose of the present invention is to disclose a core-shell hydrogel microsphere preparation device to solve one or more technical problems existing in the prior art and provide at least one beneficial option or create conditions.

[0008] The first aspect of the present invention is to provide a device for preparing core-shell hydrogel microspheres.

[0009] The core-shell hydrogel microsphere preparation device includes a microfluidic chip and a hydrophobic connecting tube. The microfluidic chip is provided with a core phase flow channel, a shell phase flow channel, an aqueous phase coaxial flow channel, an oil phase flow channel, a spherical cavity and an outlet flow channel. The ends of the core phase flow channel and the shell phase flow channel merge, and the confluence point is connected to the head end of the aqueous phase coaxial flow channel. The aqueous phase coaxial flow channel and the end of the oil phase flow channel intersect at, the spherical cavity is connected to the head end of the outlet flow channel, the inner diameter of the spherical 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 adapted to 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 spherical cavity, and one end of the hydrophobic connecting tube is inserted into the outlet flow channel.

[0010] The microfluidic chip is provided with the core-phase flow channel and the shell-phase flow channel that intersect, so that the shell-phase fluid wraps the core-phase fluid and flows in the water-phase coaxial flow channel. Subsequently, the coaxial fluid in the water-phase coaxial flow channel enters the spherical cavity filled with the oil-phase fluid, and is intercepted by the oil-phase fluid into a core-shell aqueous phase droplet with a diameter of about 0.2 to 2 mm. In addition, since the inner diameter of the additional hydrophobic connecting tube is less than or equal to the inner diameter of the spherical cavity, the oil-phase fluid will push the core-shell aqueous phase droplets into the hydrophobic connecting tube and form a state of "oil phase-core-shell aqueous phase-oil phase-core-shell aqueous phase" alternating liquid segments. The segment spacing of the alternating liquid segments in the hydrophobic connecting tube is affected by the flow rates of the core-phase fluid, the shell-phase fluid and the oil-phase fluid. When the feed 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 segments will also remain stable. The core-shell hydrogel microspheres can be obtained at the end of the hydrophobic connecting tube by simply cross-linking and solidifying the core-shell aqueous phase droplets in the hydrophobic connecting tube. Moreover, the core-shell hydrogel microspheres are delivered at equal time intervals, so the core-shell hydrogel microspheres can be accurately distributed and used in conjunction with automated equipment.

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

[0012] In a further application embodiment, the spherical cavity is cylindrical, the head end is connected to the oil phase flow channel, the tail end is connected to the outlet flow channel, the water phase axial flow channel is connected to the side wall of the spherical cavity, and the water phase axial flow channel, the oil phase flow channel and the outlet flow channel form a T-junction.

[0013] In a further application implementation, the central axis of the core phase flow channel is on the same straight line as the central axis of the water phase axial flow channel, there are two shell phase flow channels, which are connected to the confluence point from both sides, and the core phase flow channel, the two shell phase flow channels and the water phase axial flow channel form a cross 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 phase axial flow channel is 0.2~0.7 mm, and the inner diameter of the water phase axial flow channel is larger than the inner diameters 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 head ends 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 spheroidizing cavity is the same as the inner diameter of the water coaxial flow channel, and the water coaxial flow channel is perpendicular to the spheroidizing 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 port of the hydrophobic connecting tube inserted into the outlet flow channel is 0-0.2 mm away from the end of the spheroidizing cavity.

[0019] Some types of core-shell aqueous droplets require additional processing before crosslinking and solidification. For example, when the shell fluid utilizes a photocrosslinkable hydrogel material such as methacryloylated hyaluronic acid (HAMA) or methacryloylated gelatin (GelMA), the core-shell hydrogel microsphere preparation apparatus further includes a light source, and the hydrophobic connecting tube is a translucent or transparent component, and the light source illuminates the hydrophobic connecting tube. When the shell fluid utilizes a low-temperature thermal crosslinkable material such as type I collagen hydrogel, Matrigel hydrogel, or decellularized extracellular matrix (dECM) hydrogel, the core-shell hydrogel microsphere preparation apparatus further includes a heat source to supply heat to the hydrophobic connecting tube.

[0020] In a further application embodiment, the oil phase fluid is a volatile fluorinated oil, which can evaporate completely within a few seconds after being exposed to an air environment, and thus will 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 liquid dispensing system: A support plate, wherein a slideway is provided on the support plate; The mobile unit includes a mobile platform, an X-direction slide rail and a Y-direction slide rail, the Y-direction slide rail is vertically arranged on the slide rail, the Y-direction slide rail can move along the Y direction on the slide rail, the X-direction slide rail is vertically arranged on the Y-direction slide rail, the X-direction slide rail can move along the X direction on the Y-direction slide rail, and the mobile platform is fixed above the X-direction slide rail.

[0022] The end of the hydrophobic connecting tube is fixed above the mobile platform, and a perforated plate for carrying the core-shell hydrogel microspheres is placed on the mobile platform. The mobile unit can align the end of the hydrophobic connecting tube with any small hole on the perforated plate. Once the hydrophobic connecting tube can stably discharge material at intervals, the moving distance and interval of the mobile unit can be controlled to accurately ensure that the same number of core-shell hydrogel microspheres are placed in each hole on the perforated plate.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) The core-shell hydrogel microsphere preparation device provided by the present invention has the advantages of easy operation, high reliability and repeatability, and low cost; (2) The core-shell hydrogel microsphere preparation device of the present invention has stable and controllable sphere size, sphere formation rate and microsphere spacing during the core-shell hydrogel microsphere preparation process. The core-shell hydrogel microspheres can be directly connected to the automated spotting equipment after being discharged from the hydrophobic connecting tube, thereby realizing the simple and stable construction of high-throughput core-shell hydrogel microsphere arrays. When applied to the field of drug evaluation, it can greatly reduce manual operations and improve experimental efficiency and result reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a three-dimensional view of the microfluidic chip described in Example 1; Figure 2 1 is an exploded view of the microfluidic chip described in Example 1; Figure 3 1 is a top view of the microfluidic chip described in Example 1; Figure 4 Schematic diagram of the fluid flow of the microfluidic chip described in Example 1. DETAILED DESCRIPTION

[0025] In the description of the present invention, if there is a description of first, second, etc., 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 the indicated technical features or implicitly indicating the order of the indicated technical features.

[0026] The terms "preferably," "more preferably," and the like, used herein refer to embodiments of the present invention that may provide certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the present invention.

[0027] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are understood to include any and all subranges subsumed therein.

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of the present invention.

[0029] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0030] Example 1 A process for preparing core-shell hydrogel microspheres comprises: (A) Microfluidic chip design: The microfluidic chip 1 is composed of an upper layer 2 and a lower layer 3, both of which are made of 2 mm thick polydimethylsiloxane (PDMS). The fluid channels in the microfluidic chip 1 are all circular in cross-section. 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, an aqueous phase axial 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 spherical 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 core-phase flow channel 4 and the shell-phase flow channel 6 each have a disc-shaped inlet 5 with a diameter of 0.4 mm. The central axis of the core-phase flow channel 4 is aligned with the central axis of the water-phase coaxial flow channel 7. There are two shell-phase flow channels 6, one connecting to the confluence point from either side. The core-phase flow channel 4, the two shell-phase flow channels 6, and the water-phase coaxial flow channel 7 form a cross-junction. The spheroidizing cavity 8 is cylindrical, with its head end connected to the oil-phase flow channel 9 and its tail end connected to the outlet flow channel 10. The water-phase coaxial flow channel 7 is connected to the sidewall of the spheroidizing cavity 8. The water-phase coaxial flow channel 7, the oil-phase flow channel 9, and the outlet flow channel 10 form a T-junction.

[0031] (B) Design and assembly of the hydrophobic connecting tube: The hydrophobic connecting 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 hydrophobic connecting tube is inserted into the outlet flow channel and directly connected to the end of the spheroidizing cavity seamlessly.

[0032] (C) Preparation of Core-Shell Aqueous Phase Droplets: Shell phase fluid 11 is a GelMA solution containing the photoinitiator LAP. Core phase fluid 12 and shell phase fluid 11 merge at the aqueous phase coaxial flow channel 7 and flow coaxially into the sphering cavity 8 filled with oil phase fluid 14. Under the action of surface tension, a core-shell encapsulated structure of aqueous phase 13 is initially formed, filling the sphering cavity 8. Within the sphering cavity 8, aqueous phase 13 prevents oil phase fluid 14 from entering the hydrophobic connecting tube. The obstructed flow of oil phase fluid 14 shears aqueous phase 13 into core-shell aqueous phase droplets 15 and pushes them into the interior of the hydrophobic connecting tube. Because the inner diameters of the sphering cavity 8 and the hydrophobic connecting tube are both 0.2 mm, the oil phase fluid 14 and the core-shell aqueous phase droplets 15 alternately form an "oil phase-core-shell aqueous phase-oil phase-core-shell aqueous phase" state.

[0033] (D) Curing, forming and collection: The core-shell aqueous phase droplets 15 are irradiated by blue light with a wavelength of about 405 nm in the transparent hydrophobic connecting tube to achieve cross-linking and curing of the shell layer. Subsequently, they can be connected to a liquid distribution system to construct a high-throughput core-shell hydrogel microsphere array.

[0034] Example 2 A process for preparing core-shell hydrogel microspheres comprises: (A) Microfluidic chip design: The microfluidic chip consists of two layers, upper and lower, each constructed of 3 mm thick polydimethylsiloxane (PDMS). 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-phase 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 spherical 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 collinear with the central axis of the water-phase coaxial flow channel. There are two shell-phase flow channels, each connected to a junction from either side. The core-phase flow channel, the two shell-phase flow channels, and the water-phase coaxial flow channel form a cross-junction. The spheroidizing cavity is cylindrical, with a head end connected to the oil phase flow channel and a tail end connected to the outlet flow channel. The water phase coaxial flow channel is connected to the side wall of the spheroidizing cavity. The water phase coaxial flow channel, the oil phase flow channel and the outlet flow channel form a T-junction.

[0035] (B) Design and assembly of a hydrophobic connecting tube: The hydrophobic connecting tube is made of transparent soluble polytetrafluoroethylene (PFA), has an outer diameter of 0.5 mm and an inner diameter of 0.4 mm, and its head end is inserted into the outlet flow channel, 0.05 mm away from the end of the spheroidizing cavity.

[0036] (C) Preparation of core-shell aqueous phase droplets: The shell phase fluid is a GelMA solution containing the photoinitiator LAP. The core phase fluid and the shell phase fluid converge at the same axial flow channel of the aqueous phase and flow coaxially into the spherical cavity filled with the oil phase fluid. Under the action of surface tension, a core-shell coating structure of the aqueous phase is initially formed and fills the spherical cavity. Within the spherical cavity, the aqueous phase hinders the oil phase fluid from entering the hydrophobic connecting tube. The obstructed flow of the oil phase fluid shears the aqueous phase into core-shell aqueous phase droplets and pushes them into the interior of the hydrophobic connecting tube. Since the inner diameter of the spherical cavity and the hydrophobic connecting tube are both 0.4 mm, the oil phase fluid and the core-shell aqueous phase droplets alternately form an "oil phase-core-shell aqueous phase-oil phase-core-shell aqueous phase" state.

[0037] (D) Curing, molding and collection: The core-shell aqueous phase droplets are irradiated by blue light with a wavelength of about 405 nm in the transparent hydrophobic connecting tube to achieve cross-linking and curing of the shell layer, which can then be connected to a distribution system to construct a high-throughput core-shell hydrogel microsphere array.

[0038] Example 3 A process for preparing core-shell hydrogel microspheres comprises: (A) Microfluidic chip design: The microfluidic chip consists of two layers, upper and lower, each made of 4 mm thick polydimethylsiloxane (PDMS). 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-phase coaxial flow channel with an inner diameter of 0.5 mm, an oil-phase flow channel with an inner diameter of 0.8 mm, a spherical 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 collinear with the central axis of the water-phase coaxial flow channel. There are two shell-phase flow channels, each connected to a junction from either side. The core-phase flow channel, the two shell-phase flow channels, and the water-phase coaxial flow channel form a cross-junction. The spheroidizing cavity is cylindrical, with a head end connected to the oil phase flow channel and a tail end connected to the outlet flow channel. The water phase coaxial flow channel is connected to the side wall of the spheroidizing cavity. The water phase coaxial flow channel, the oil phase flow channel and the outlet flow channel form a T-junction.

[0039] (B) Design and assembly of the hydrophobic connecting tube: The hydrophobic connecting 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 hydrophobic connecting tube is inserted into the outlet flow channel, 0.1 mm away from the end of the spherical cavity.

[0040] (C) Preparation of core-shell aqueous droplets: The shell phase fluid is a HAMA solution containing the photoinitiator LAP. The core and shell phase fluids merge at the aqueous phase's coaxial flow channel and flow coaxially into the spheroidizing cavity filled with the oil phase fluid. Surface tension initially forms a core-shell structure of the aqueous phase, filling the spheroidizing cavity. Within the spheroidizing cavity, the aqueous phase blocks the oil phase fluid from entering the hydrophobic connecting tube. The obstructed flow of the oil phase shears the aqueous phase into core-shell aqueous droplets, pushing them into the hydrophobic connecting tube. Because the inner diameter of the hydrophobic connecting tube is 0.6 mm, slightly narrower than that of the spheroidizing cavity, the core-shell aqueous droplets are squeezed into an elliptical shape. The oil phase fluid and the core-shell aqueous droplets alternate, forming an "oil phase-core-shell aqueous phase-oil phase-core-shell aqueous phase" pattern.

[0041] (D) Curing, molding and collection: The core-shell aqueous phase droplets are irradiated by blue light with a wavelength of about 405 nm in the transparent hydrophobic connecting tube to achieve cross-linking and curing of the shell layer, which can then be connected to a distribution system to construct a high-throughput core-shell hydrogel microsphere array.

[0042] Example 4 A process for preparing core-shell hydrogel microspheres comprises: (A) Microfluidic chip design: The microfluidic chip consists of two layers, an upper layer and a lower layer, both of which are made of 5 mm thick polydimethylsiloxane (PDMS). 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-phase 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 spherical 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 collinear with the central axis of the water-phase coaxial flow channel. There are two shell-phase flow channels, each connected to a junction from either side. The core-phase flow channel, the two shell-phase flow channels, and the water-phase coaxial flow channel form a cross-junction. The spheroidizing cavity is cylindrical, with a head end connected to the oil phase flow channel and a tail end connected to the outlet flow channel. The water phase coaxial flow channel is connected to the side wall of the spheroidizing cavity. The water phase coaxial flow channel, the oil phase flow channel and the outlet flow channel form a T-junction.

[0043] (B) Design and assembly of the hydrophobic connecting tube: The hydrophobic connecting 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 hydrophobic connecting tube is inserted into the outlet flow channel, 0.15 mm away from the end of the spherical cavity.

[0044] (C) Preparation of core-shell aqueous droplets: The shell phase fluid is a type I collagen hydrogel solution. The core and shell phase fluids converge at the coaxial flow channel of the aqueous phase and flow coaxially into the spherical cavity filled with the oil phase fluid. Surface tension initially forms a core-shell structure of the aqueous phase, filling the spherical cavity. Within the spherical cavity, the aqueous phase blocks the oil phase fluid from entering the hydrophobic connecting tube. The blocked flow of the oil phase shears the aqueous phase into core-shell aqueous droplets and pushes them into the hydrophobic connecting tube. Because the inner diameters of the spherical cavity and the hydrophobic connecting tube are both 1.2 mm, the oil phase fluid and the core-shell aqueous droplets alternately form an "oil phase-core-shell aqueous phase-oil phase-core-shell aqueous phase" pattern.

[0045] (D) Curing and Collection: The hydrophobic connecting tube is heated to a temperature of about 37° C. to crosslink and solidify the type I collagen hydrogel in the shell layer, thereby collecting the core-shell hydrogel microspheres at the outlet at the end of the hydrophobic connecting tube.

[0046] Example 5 A process for preparing core-shell hydrogel microspheres comprises: (A) Microfluidic chip design: The microfluidic chip consists of two layers, an upper layer and a lower layer, both of which are made of 5 mm thick polydimethylsiloxane (PDMS). 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-phase 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 spherical 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 collinear with the central axis of the water-phase coaxial flow channel. There are two shell-phase flow channels, each connected to a junction from either side. The core-phase flow channel, the two shell-phase flow channels, and the water-phase coaxial flow channel form a cross-junction. The spheroidizing cavity is cylindrical, with a head end connected to the oil phase flow channel and a tail end connected to the outlet flow channel. The water phase coaxial flow channel is connected to the side wall of the spheroidizing cavity. The water phase coaxial flow channel, the oil phase flow channel and the outlet flow channel form a T-junction.

[0047] (B) Design and assembly of the hydrophobic connecting tube: The hydrophobic connecting 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 hydrophobic connecting tube is inserted into the outlet flow channel, 0.15 mm away from the end of the spherical cavity.

[0048] (C) Preparation of core-shell aqueous phase droplets: The shell phase fluid is a Matrigel hydrogel solution. The core phase fluid and the shell phase fluid merge at the same axial flow channel of the aqueous phase and flow coaxially into the spherical cavity filled with the oil phase fluid. Under the action of surface tension, a core-shell structure of the aqueous phase is initially formed, filling the spherical cavity. Within the spherical cavity, the aqueous phase blocks the oil phase fluid from entering the hydrophobic connecting tube. The blocked flow of the oil phase fluid shears the aqueous phase into core-shell aqueous phase droplets and pushes them into the interior of the hydrophobic connecting tube. Because the inner diameter of the spherical cavity and the hydrophobic connecting tube is both 1.2 mm, the oil phase fluid and the core-shell aqueous phase droplets alternately form an "oil phase-core-shell aqueous phase-oil phase-core-shell aqueous phase" state.

[0049] (D) Curing and Collection: The hydrophobic connecting tube is heated to a temperature of approximately 37°C to allow the Matrigel hydrogel in the shell to crosslink and solidify. The tube can then be connected to a liquid distribution system to construct a high-throughput core-shell hydrogel microsphere array.

[0050] Example 6 A process for preparing core-shell hydrogel microspheres comprises: (A) Microfluidic chip design: The microfluidic chip consists of two layers, upper and lower, each constructed of 6 mm thick polydimethylsiloxane (PDMS). The fluidic channels in the microfluidic chip are all circular in cross-section. The fluidic 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-phase coaxial flow channel with an inner diameter of 0.7 mm, an oil-phase flow channel with an inner diameter of 2 mm, a spherical 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 collinear with the central axis of the water-phase coaxial flow channel. There are two shell-phase flow channels, each connected to a junction on either side. The core-phase flow channel, the two shell-phase flow channels, and the water-phase coaxial flow channel form a cross-junction. The spheroidizing cavity is cylindrical, with a head end connected to the oil phase flow channel and a tail end connected to the outlet flow channel. The water phase coaxial flow channel is connected to the side wall of the spheroidizing cavity. The water phase coaxial flow channel, the oil phase flow channel and the outlet flow channel form a T-junction.

[0051] (B) Design and assembly of the hydrophobic connecting tube: The hydrophobic connecting tube is made of transparent PTFE, with an outer diameter of 2 mm and an inner diameter of 1.8 mm. The first end of the hydrophobic connecting tube is inserted into the outlet flow channel, 0.2 mm away from the end of the spheroidizing cavity.

[0052] (C) Preparation of core-shell aqueous droplets: The shell fluid is a Matrigel hydrogel solution. The core and shell fluids merge at the aqueous phase's axial flow channel and flow coaxially into the spherical cavity filled with the oil phase fluid. Surface tension initially forms a core-shell structure of the aqueous phase, filling the spherical cavity. Within the spherical cavity, the aqueous phase blocks the oil phase fluid from entering the hydrophobic connecting tube. The obstructed oil phase shears the aqueous phase into core-shell aqueous droplets and pushes them into the hydrophobic connecting tube. Because the inner diameter of the hydrophobic connecting tube is 1.8 mm, slightly narrower than the inner diameter of the spherical cavity, the core-shell aqueous droplets are squeezed into an elliptical shape. The oil phase fluid and the core-shell aqueous droplets alternate, forming an "oil phase-core-shell aqueous phase-oil phase-core-shell aqueous phase" state.

[0053] (D) Curing and Collection: The hydrophobic connecting tube is heated to a temperature of approximately 37°C to allow the Matrigel hydrogel in the shell to crosslink and solidify. The tube can then be connected to a liquid distribution system to construct a high-throughput core-shell hydrogel microsphere array.

[0054] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A core-shell hydrogel microsphere preparation device, characterized in that: The invention comprises a microfluidic chip and a hydrophobic connecting tube, wherein the microfluidic chip is provided with a core phase flow channel, a shell phase flow channel, a water phase axial flow channel, an oil phase flow channel, a spherical cavity and an outlet flow channel, the ends of the core phase flow channel and the shell phase flow channel merge, and the merging point is connected to the head end of the water phase axial flow channel, the ends of the water phase axial flow channel and the oil phase flow channel intersect at the spherical cavity, the spherical cavity is connected to the head end of the outlet flow channel, the inner diameter of the spherical 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 adapted to 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 spherical cavity, and one end of the hydrophobic connecting tube is inserted into the outlet flow channel.

2. The core-shell hydrogel microsphere preparation device according to claim 1, characterized in that: The spheroidizing cavity is cylindrical, with its head end connected to the oil phase flow channel and its tail end connected to the outlet flow channel. The water phase axial flow channel is connected to the side wall of the spheroidizing cavity. The water phase axial flow channel, the oil phase flow channel and the outlet flow channel form a T-shaped junction.

3. The core-shell hydrogel microsphere preparation device according to claim 1, characterized in that: The central axis of the core phase flow channel is in the same straight line as the central axis of the water phase axial flow channel. There are two shell phase flow channels, which are connected to the confluence point from both sides. The core phase flow channel, the two shell phase flow channels and the water phase axial flow channel form a cross-shaped confluence.

4. The core-shell hydrogel microsphere preparation device 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 phase axial flow channel is 0.2~0.7 mm, and the inner diameter of the water phase axial flow channel is larger than the inner diameters 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.

5. The core-shell hydrogel microsphere preparation device according to claim 4, characterized in that: The length of the spheroidizing cavity is the same as the inner diameter of the water coaxial flow channel, and the water coaxial flow channel is perpendicular to the spheroidizing cavity.

6. The core-shell hydrogel microsphere preparation device according to claim 1, characterized in that: The material of the hydrophobic connecting tube is selected from polytetrafluoroethylene, soluble polytetrafluoroethylene or ethylene-tetrafluoroethylene copolymer.

7. The core-shell hydrogel microsphere preparation device according to claim 1, characterized in that: The port of the hydrophobic connecting tube inserted into the outlet flow channel is 0-0.2 mm away from the end of the spherical cavity.

8. The core-shell hydrogel microsphere preparation device according to any one of claims 1 to 7, characterized in that: A light source is also included. The hydrophobic connecting tube is a translucent or transparent component. The light source illuminates the hydrophobic connecting tube.

9. The core-shell hydrogel microsphere preparation device according to any one of claims 1 to 7, characterized in that: A heat source is also included, and the heat source supplies heat to the hydrophobic connecting pipe.

10. The core-shell hydrogel microsphere preparation device according to any one of claims 1 to 7, characterized in that: Also includes a dispensing system: A support plate, wherein a slideway is provided on the support plate; The mobile unit includes a mobile platform, an X-direction slide rail and a Y-direction slide rail, the Y-direction slide rail is vertically arranged on the slide rail, the Y-direction slide rail can move along the Y direction on the slide rail, the X-direction slide rail is vertically arranged on the Y-direction slide rail, the X-direction slide rail can move along the X direction on the Y-direction slide rail, and the mobile platform is fixed above the X-direction slide rail.

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