Porous core-shell hydrogel microspheres as well as preparation method and application thereof

Abstract

The invention discloses a porous core-shell hydrogel microsphere as well as a preparation method and application thereof, and belongs to the technical field of hydrogel microspheres. The preparation method comprises the following steps: shearing a liquid flow of an inner core phase by a liquid flow of a shell phase by adopting a liquid drop micro-fluidic chip to form a first liquid drop of which the inner core phase is wrapped by the shell phase; the shell phase contains methacrylated hyaluronic acid, a photocuring cross-linking agent and a photoinitiator, the core phase contains polyoxyethylene and gelatin, and the concentration of the gelatin is 0.01-0.04 g / mL; shearing a liquid drop flow formed by the first liquid drops through the oil phase to form second liquid drops; the second liquid drops are solidified through ultraviolet irradiation to form core-shell hydrogel microspheres, polyoxyethylene and gelatin in the core-shell hydrogel microspheres are removed, an oil phase on the surfaces of the core-shell hydrogel microspheres is removed, and the porous core-shell hydrogel microspheres are obtained. The core-shell structure hydrogel microspheres with porous shells can be prepared, cell proliferation and extension are facilitated, and the core-shell structure hydrogel microspheres can be applied to treatment of cartilage defects.

Description

Technical Field

[0001] The present application relates to the field of hydrogel microspheres, and in particular to porous core-shell hydrogel microspheres and a preparation method and application thereof. Background Art

[0002] Osteoarticular cartilage disease is a type of degenerative disease characterized by degeneration of articular cartilage, sclerosis of the underlying bone, and synovial inflammation. It seriously affects the quality of life of patients and places a heavy burden on the public health system. At present, the clinical treatments for this type of disease mainly include drug analgesia, intra-articular injection, biological agents, and joint replacement, but these methods are mostly aimed at relieving symptoms and it is difficult to achieve true regeneration and functional restoration of cartilage. Therefore, exploring new biomaterials and construction strategies that can effectively promote the regeneration of cartilage tissue has become an important research direction in tissue engineering and regenerative medicine.

[0003] In recent years, core-shell structures have garnered widespread attention due to their wide-ranging applications in tissue engineering, drug delivery, and biomaterials. Core-shell microspheres, a typical composite scaffold system, possess unique structural advantages. Their core and shell are composed of different materials. This structural design allows for highly controllable material composition and functional distribution, demonstrating significant potential for simulating cellular microenvironments, regulating cell behavior, and constructing functional tissue models.

[0004] However, traditional core-shell structures typically use a dense or low-porosity shell, which limits the effective exchange of nutrients and metabolic waste, and cannot fully support the proliferation and differentiation of chondrocytes. In contrast, fully porous structures, while advantageous in terms of material exchange, often lack sufficient structural stability and spatial isolation capabilities, making it difficult to provide a suitable three-dimensional space for cell growth. Therefore, how to introduce a porous shell into the core-shell structure while balancing mass transfer efficiency and structural function has become the focus and difficulty of current research. Summary of the Invention

[0005] The present application provides a porous core-shell hydrogel microsphere and its preparation method and application. The preparation method can prepare hydrogel microspheres with a porous shell and a core-shell structure, which is beneficial to cell proliferation and expansion and can be used to treat cartilage defects.

[0006] This application is implemented as follows: In a first aspect, the present application provides a method for preparing porous core-shell hydrogel microspheres, comprising the following steps: A droplet microfluidic chip is used to cause the outer shell phase to shear the inner core phase, forming a first droplet in which the outer shell phase encapsulates the inner core phase. The outer shell phase contains methacryloylated hyaluronic acid, a photocurable crosslinker, and a photoinitiator, while the inner core phase contains polyethylene oxide and gelatin, with the gelatin concentration ranging from 0.01 to 0.04 g / mL. The oil phase shears the droplet stream formed by the first droplet, thereby forming a second droplet; The second droplet is solidified by ultraviolet light irradiation to form core-shell hydrogel microspheres, the polyethylene oxide and gelatin in the core-shell hydrogel microspheres are removed, and the oil phase on the surface of the core-shell hydrogel microspheres is removed to obtain porous core-shell hydrogel microspheres.

[0007] In one possible embodiment, the concentration of the methacryloyl hyaluronic acid in the shell phase is 0.002-0.012 g / mL, and the average molecular weight of the methacryloyl hyaluronic acid is 1.5 million-2.5 million.

[0008] In one possible embodiment, the photocurable cross-linking agent is selected from polyethylene glycol diacrylate, and the volume concentration of polyethylene glycol diacrylate is 0.5-3%.

[0009] In one possible embodiment, the concentration of the photoinitiator is 0.001-0.005 g / mL; the photoinitiator is phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt.

[0010] In one possible embodiment, the concentration of polyethylene oxide in the inner core phase is 0.01-0.016 g / mL.

[0011] In one possible embodiment, the oil phase contains dimethicone and a surfactant.

[0012] In one possible embodiment, the oil phase includes a hydrofluoroether and a non-ionic fluorocarbon surfactant, and the volume proportion of the non-ionic fluorocarbon surfactant in the oil phase is 1-2%.

[0013] In one possible embodiment, the inner core phase is loaded with cells; optionally, the cells include bone marrow mesenchymal stem cells, fibroblasts, cardiomyocytes, and cancer cells.

[0014] In one possible embodiment, the droplet microfluidic chip includes a first feed hole for introducing the shell phase, a second feed hole for introducing the core phase, a third feed hole for introducing the oil phase, a first liquid flow channel connected to the first feed hole, a second liquid flow channel connected to the second feed hole, and a third liquid flow channel connected to the third feed hole, and the third liquid flow channel is arranged crosswise with the first liquid flow channel; the first liquid flow channel includes a first section, a second section and a third section arranged in sequence, the first section and the third section are straight sections, the second section consists of multiple S-shaped bends, the third liquid flow channel is connected to the third section, and the second liquid flow channel is connected to the first section and the two are arranged at an acute angle.

[0015] In a second aspect, the present application provides a porous core-shell hydrogel microsphere, which is prepared by the preparation method of the porous core-shell hydrogel microsphere of the first aspect.

[0016] In a third aspect, the present application provides a use of the porous core-shell hydrogel microspheres according to the second aspect in the preparation of cartilage repair materials and osteogenic repair materials.

[0017] The beneficial effects of this application are at least as follows: The method for preparing porous core-shell hydrogel microspheres of the present invention uses a droplet microfluidic chip to cause the liquid flow of the shell phase to shear the liquid flow of the core phase, forming a first droplet of the shell phase enveloping the core phase. The gelatin concentration in the core phase is low, and the polyethylene oxide in the core phase is not easily dispersed by the gelatin, allowing the polyethylene oxide to converge to form a large sphere. The droplet flow formed by the first droplet is then sheared by the oil phase to form a second droplet with the oil phase enveloping the surface of the first droplet. The second droplet is then cured by ultraviolet light irradiation to form a core-shell hydrogel microsphere. After the polyethylene oxide, gelatin, and oil phase in the core-shell hydrogel microsphere are removed, a core-shell hydrogel microsphere with a porous shell and a hollow interior is formed.

[0018] It has been verified that the porous core-shell hydrogel microspheres of the embodiment of the present application have a core-shell structure, and the outer shell is porous, which is conducive to cell proliferation and expansion, and can be used to treat cartilage defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 This is a photo of the porous core-shell hydrogel microspheres of Example 1 under a fluorescence microscope; Figure 2These are photos of the microspheres prepared in Comparative Example 1, Example 1, and Comparative Example 2 under a fluorescence microscope; Figure 3 The cross-linking conditions of PEGDA concentrations of 1%, 2%, 3%, 4%, and 5% at UV irradiation for 0s and 30s respectively; Figure 4 This is the cell live-dead staining image of the biocompatibility of HAMA hydrogel; Figure 5 The cell survival rate results of HAMA hydrogel are shown; Figure 6 These are photos of bone marrow mesenchymal stem cells in the porous core-shell hydrogel microspheres of Example 2 at different focal lengths on day 1; Figure 7 This is a diagram showing the expansion and proliferation of bone marrow mesenchymal stem cells in the porous core-shell hydrogel microspheres of Example 2 on the 7th day; Figure 8 Schematic diagram of the design of the droplet microfluidic chip; Figure 9 This is a photo of the intersection of the first liquid flow channel and the second liquid flow channel of the droplet microfluidic chip under an optical microscope.

[0021] Icon: 11-first feed hole; 12-second feed hole; 13-third feed hole; 14-first liquid flow channel; 141-first section; 142-second section; 143-third section; 15-second liquid flow channel; 16-third liquid flow channel. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.

[0023] The following is a detailed description of the porous core-shell hydrogel microspheres and their preparation methods and applications according to the embodiments of the present application: In a first aspect, the present application provides a method for preparing porous core-shell hydrogel microspheres, comprising the following steps: A droplet microfluidic chip is used to cause the outer shell phase to shear the inner core phase, forming a first droplet in which the outer shell phase encapsulates the inner core phase. The outer shell phase contains methacryloylated hyaluronic acid, a photocurable crosslinker, and a photoinitiator, while the inner core phase contains polyethylene oxide and gelatin, with the gelatin concentration ranging from 0.01 to 0.04 g / mL. The oil phase shears the droplet stream formed by the first droplet, thereby forming a second droplet; The second droplet is solidified by ultraviolet light irradiation to form core-shell hydrogel microspheres, the polyethylene oxide and gelatin in the core-shell hydrogel microspheres are removed, and the oil phase on the surface of the core-shell hydrogel microspheres is removed to obtain porous core-shell hydrogel microspheres.

[0024] The method for preparing porous core-shell hydrogel microspheres of the embodiment of the present application uses a droplet microfluidic chip to make the liquid flow of the shell phase shear the liquid flow of the core phase, forming a first droplet of the shell phase enveloping the core phase, the gelatin concentration in the core phase is low, the polyethylene oxide in the core phase is not easily dispersed by gelatin, so that the polyethylene oxide can converge to form a large sphere, and some scattered gelatin and polyethylene oxide are incorporated into the shell phase. Then, the droplet flow formed by the first droplet is sheared by the oil phase to form a second droplet with the oil phase enveloping the surface of the first droplet, and then the second droplet is solidified by ultraviolet light to form a core-shell hydrogel microsphere. After removing the polyethylene oxide and gelatin in the core-shell hydrogel microsphere and removing the oil phase layer, a core-shell structure hydrogel microsphere with a porous shell and a hollow interior is formed. Optionally, the gelatin concentration in the embodiment of the present application is any one of 0.01 g / mL, 0.02 g / mL, 0.03 g / mL and 0.04 g / mL or a value between any two of them.

[0025] The inventors of this application found in their research that the concentration of gelatin has an important influence on the preparation of core-shell structured hydrogel microspheres. If the concentration of gelatin is not within the range specified in this application, such as less than 0.01 g / mL (for example, 0.005 g / mL), the hydrogel microspheres have very few pores; if the concentration of gelatin is greater than 0.04 g / mL (for example, 0.08 g / mL), hydrogel microspheres with a core-shell structure cannot be formed.

[0026] The concentration of methacryloylated hyaluronic acid (HAMA) in the shell phase is 0.002-0.012 g / mL, and the average molecular weight of the methacryloylated hyaluronic acid is 1.5 million to 2.5 million. Alternatively, the concentration of the methacryloylated hyaluronic acid is any one of 0.002 g / mL, 0.004 g / mL, 0.006 g / mL, 0.008 g / mL, 0.010 g / mL, and 0.012 g / mL, or a value between any two thereof. Alternatively, the average molecular weight of the methacryloylated hyaluronic acid is any one of 1.5 million, 1.6 million, 1.7 million, 1.8 million, 1.9 million, 2 million, 2.1 million, 2.2 million, 2.3 million, 2.4 million, and 2.5 million, or a value between any two thereof.

[0027] In addition, the photocurable crosslinker is selected from polyethylene glycol diacrylate (PEGDA), and the volume concentration of polyethylene glycol diacrylate is 0.5-3%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, or 3%. The concentration of the photoinitiator is 0.001-0.005 g / mL, for example, 0.001 g / mL, 0.002 g / mL, 0.003 g / mL, 0.004 g / mL, or 0.005 g / mL. Optionally, the photoinitiator is lithium phenyl (2,4,6-trimethylbenzoyl) phosphate (LAP).

[0028] Illustratively, the concentration of polyethylene oxide (PEO) in the inner core phase is 0.01-0.016 g / mL, for example, 0.01 g / mL, 0.011 g / mL, 0.012 g / mL, 0.013 g / mL, 0.014 g / mL, 0.015 g / mL or 0.016 g / mL.

[0029] Furthermore, in some embodiments, the inner core phase is loaded with cells; for example, the loaded cells include bone marrow mesenchymal stem cells. By loading cells in the inner core phase, the cells are embedded in the inner core of the hydrogel microsphere, which is conducive to simulating the mechanical environment of the cartilage matrix and promoting cell growth and infiltration.

[0030] For example, the step of loading cells into the inner core phase includes: digesting the cultured cells, centrifuging, removing the supernatant, and then adding the inner core phase (at a concentration of 2×10 7 / mL concentration) and mix.

[0031] In one embodiment, the oil phase contains dimethicone and a surfactant. In some embodiments, the surfactant includes cyclopentasiloxane and trimethylsiloxysilicate. The surfactant can be broken down by a demulsifier to achieve the effect of eluting the oil phase.

[0032] In another embodiment, when the core phase is loaded with cells, the oil phase includes a hydrofluoroether and a nonionic fluorocarbon surfactant, with the nonionic fluorocarbon surfactant comprising 1-2% by volume. Hydrofluoroethers are volatile and biocompatible, and the porous core-shell hydrogel microspheres evaporate after being placed in a well-ventilated area for a period of time, allowing the oil phase to be removed.

[0033] In addition, it should be noted that the droplet microfluidic chip of the embodiment of the present application is not limited to a specific structure as long as it can achieve the above-mentioned function of forming the second droplet. Figure 8As shown, the droplet microfluidic chip includes a first feed hole 11 for introducing the shell phase, a second feed hole 12 for introducing the core phase, a third feed hole 13 for introducing the oil phase, a first liquid flow channel 14 connected to the first feed hole 11, a second liquid flow channel 15 connected to the second feed hole 12, and a third liquid flow channel 16 connected to the third feed hole 13. The third liquid flow channel 16 is arranged crosswise with the first liquid flow channel 14; the first liquid flow channel 14 includes a first section 141, a second section 142 and a third section 143 arranged in sequence, the first section 141 and the third section 143 are straight sections, the second section 142 consists of a plurality of S-shaped bends, the third liquid flow channel 16 is connected to the third section 143, and the second liquid flow channel 15 is connected to the first section 141 and is arranged at an acute angle therebetween.

[0034] The shell phase enters the first liquid flow channel 14 from the first feed hole 11, and the core phase enters the second liquid flow channel 15 from the second feed hole 12. The shell and core phases mix at the intersection of the second liquid flow channel 15 and the first section 141 of the first liquid flow channel 14, where they are sheared to form a first droplet. The first droplet flows through the second section 142, the third section 143, and the third liquid flow channel 16. The oil phase shears the droplet flow formed by the first droplet, forming a second droplet. The multiple S-shaped bends in the second section 142 ensure a more uniform and stable fusion of the shell and core phases.

[0035] In a second aspect, the present application provides a porous core-shell hydrogel microsphere, which is prepared by the above-mentioned method for preparing porous core-shell hydrogel microspheres.

[0036] In a third aspect, the present application provides an application of the above-mentioned porous core-shell hydrogel microspheres in the preparation of cartilage repair materials and osteogenic repair materials.

[0037] The core-shell hydrogel microspheres prepared in the present application not only have a core-shell structure, but also have a porous shell, which is conducive to cell proliferation and extension, and can be used to treat cartilage defects.

[0038] The porous core-shell hydrogel microspheres of the present application and their preparation method and application are further described in detail below with reference to the examples. Example

[0039] This embodiment provides a method for preparing porous core-shell hydrogel microspheres, which includes the following steps: (1) A droplet microfluidic chip was used to mix the shell phase and the core phase and form a first droplet through shearing. The shell phase contained 0.005 g / mL methacryloyl hyaluronic acid dissolved in PBS, 1% polyethylene glycol diacrylate, and 0.005 g / mL LAP photoinitiator, while the core phase contained 0.016 g / mL polyethylene oxide and 0.04 g / mL gelatin dissolved in PBS.

[0040] (2) The oil phase shears the droplet stream formed by the first droplet, thereby forming a second droplet; wherein the oil phase contains dimethyl silicone oil and a surfactant, and the surfactant includes cyclopentasiloxane and trimethylsiloxysilicate.

[0041] (3) The second droplet is collected and pre-cured at the outlet of the microfluidic chip using a 5W UV flashlight. The droplet is then placed in a culture bottle (with culture medium) and irradiated under 15W UV light for about 30 seconds to solidify the second droplet and form core-shell hydrogel microspheres. When the hydrogel microspheres enter the culture medium, they are slightly shaken so that the core phase polyethylene oxide and gelatin dissolve in the culture medium, thereby obtaining porous core-shell hydrogel microspheres. The porous core-shell hydrogel microspheres prepared are as follows. Figure 1 and Figure 2 As shown in (b), it not only has a clear core-shell structure, but also has relatively obvious pore structures everywhere in the outer shell. Example

[0042] This embodiment provides a method for preparing cell-laden porous core-shell hydrogel microspheres, which comprises the following steps: (1) A droplet microfluidic chip was used to mix the shell phase and the core phase and form a first droplet through shearing. The shell phase contained 0.005 g / mL methacryloyl hyaluronic acid dissolved in PBS, 1% polyethylene glycol diacrylate, and 0.005 g / mL LAP photoinitiator. The core phase contained 0.016 g / mL polyethylene oxide dissolved in PBS and 0.04 g / mL gelatin. The core phase was loaded with cells at a specific ratio of 2×10 7 Bone marrow mesenchymal stem cells (BMSCs) at a concentration of 100 μg / mL.

[0043] (2) Shearing the droplet stream formed by the oil phase and the first droplet to form a second droplet; wherein the oil phase contains a hydrofluoroether and a nonionic fluorocarbon surfactant, and the volume of the nonionic fluorocarbon surfactant is 2%.

[0044] (3) The second droplet was collected and pre-cured at the outlet of the microfluidic chip using a 5W UV flashlight. The droplet was then placed in a culture bottle (with culture medium) and irradiated under 15W UV light for about 30 seconds to solidify the second droplet into core-shell hydrogel microspheres. The core-shell hydrogel microspheres were slightly shaken when entering the culture medium and then placed in a carbon dioxide incubator to allow the core phase of polyethylene oxide and gelatin to dissolve in the culture medium and the surface oil phase to evaporate, thereby obtaining porous core-shell hydrogel microspheres loaded with cells.

[0045] Comparative Example 1 This comparative example provides a method for preparing hydrogel microspheres. The preparation steps thereof are different from those of Example 1, except that, in step (1) of Comparative Example 1, the concentration of gelatin in the core phase is 0.005 g / mL. Figure 2 As shown in (a), there are very few holes in the shell and their distribution is very uneven.

[0046] Comparative Example 2 This comparative example provides a method for preparing hydrogel microspheres. The preparation steps thereof are different from those of Example 1, except that, in step (1) of Comparative Example 1, the concentration of gelatin in the core phase is 0.08 g / mL. Figure 2 As shown in (c), it does not have a core-shell structure.

[0047] Test Example 1 Prepare mixed solutions of LAP and PEGDA, where the concentration of LAP is 0.005 g / mL and the volume concentration of PEGDA is 1%, 2%, 3%, 4%, and 5%, respectively. Irradiate the mixed solutions under 15W UV for 0s and 30s. The results are shown in Figure 2. Figure 3 As shown, the results showed that after 30 seconds of irradiation, when the PEGDA in the mixed solution was 1%~3%, the mixed solution was not cross-linked; when the PEGDA in the mixed solution was 4% and 5%, the mixed solution was cross-linked.

[0048] Since PEGDA is a small molecule, although the shell phase and the core phase are immiscible with each other, they are both aqueous phases. If the PEGDA in the shell phase enters the large pores of the core or the small pores on the shell, it will cross-link with the gelatin that should have been eluted, resulting in no pores. Figure 3 The results show that when the PEGDA concentration in the mixed solution is 1-3%, PEGDA will not cross-link after UV irradiation for 30 seconds. Therefore, the PEGDA concentration in the shell phase is selected to be 1-3% in the embodiment of the present application. If this concentration is exceeded, there is a risk of non-porous.

[0049] Test Example 2 The HAMA hydrogel shell phase and core phase were prepared. The HAMA hydrogel shell phase contained 0.005 g / mL methacryloyl hyaluronic acid dissolved in PBS, 1% polyethylene glycol diacrylate, and 0.005 g / mL LAP photoinitiator. The core phase contained 0.016 g / mL polyethylene oxide dissolved in PBS, 0.04 g / mL gelatin, and cells were loaded in the core phase at a specific ratio of 2×10 7 fibroblasts / mL.

[0050] The hydrogel shell phase and the core phase were mixed and pipetted for 6 seconds, then UV light cross-linked for 30 seconds. After culturing for 1, 4, and 7 days, the cells were stained for live and dead cells. The growth, proliferation, and extension of fibroblasts were observed using a fluorescence microscope. The results are shown in Figure 2. Figure 4 、 Figure 5 shown.

[0051] The results showed that the cells stretched and proliferated well in the hydrogel.

[0052] Test Example 3 The porous core-shell hydrogel microspheres prepared in Example 2 were observed under an optical microscope on the first day. Figure 6 The results showed that the cells were mainly located in the large pores at the center of the porous core-shell hydrogel microspheres, with a small number of cells located in the outer shell.

[0053] Test Example 4 The cell-laden porous core-shell hydrogel microspheres prepared in Example 2 were stained with live-dead staining on the 7th day and observed under an optical microscope and a fluorescence microscope. The results are as follows: Figure 7 shown.

[0054] The results showed that the cells expanded and proliferated well in the porous core-shell hydrogel microspheres of Example 2.

[0055] The above are merely specific embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for preparing porous core-shell hydrogel microspheres, characterized in that: The following steps are involved: A droplet microfluidic chip is used to cause the outer shell phase to shear the inner core phase, forming a first droplet in which the outer shell phase envelops the inner core phase; wherein the outer shell phase contains methacrylated hyaluronic acid, a photocurable crosslinker, and a photoinitiator, and the inner core phase contains polyethylene oxide and gelatin, with the gelatin concentration ranging from 0.01 to 0.04 g / mL; forming second droplets by shearing the droplet stream formed by the first droplet with the oil phase; The second droplets are solidified by ultraviolet light irradiation to form core-shell hydrogel microspheres, the polyethylene oxide and the gelatin in the core-shell hydrogel microspheres are removed, and the oil phase on the surface of the core-shell hydrogel microspheres is removed to obtain porous core-shell hydrogel microspheres.

2. The method for preparing porous core-shell hydrogel microspheres according to claim 1, characterized in that: The concentration of the methacryloyl hyaluronic acid in the shell phase is 0.002-0.012 g / mL, and the average molecular weight of the methacryloyl hyaluronic acid is 1.5 million-2.5 million.

3. The method for preparing porous core-shell hydrogel microspheres according to claim 1, wherein: The photocurable cross-linking agent is selected from polyethylene glycol diacrylate, and the volume concentration of the polyethylene glycol diacrylate is 0.5-3%.

4. The method for preparing porous core-shell hydrogel microspheres according to claim 1, characterized in that: The concentration of the photoinitiator is 0.001-0.005 g / mL; the photoinitiator is phenyl (2,4,6-trimethylbenzoyl) lithium phosphate.

5. The method for preparing porous core-shell hydrogel microspheres according to claim 1, characterized in that: The concentration of polyethylene oxide in the core phase is 0.01-0.016 g / mL.

6. The method for preparing porous core-shell hydrogel microspheres according to any one of claims 1 to 5, characterized in that: The oil phase contains dimethyl silicone oil and a surfactant; or the oil phase includes hydrofluoroether and a non-ionic fluorocarbon surfactant, and the volume proportion of the non-ionic fluorocarbon surfactant in the oil phase is 1-2%.

7. The method for preparing porous core-shell hydrogel microspheres according to any one of claims 1 to 5, characterized in that: The inner core phase is loaded with cells; optionally, the cells include bone marrow mesenchymal stem cells, fibroblasts, cardiomyocytes, and cancer cells.

8. The method for preparing porous core-shell hydrogel microspheres according to any one of claims 1 to 5, characterized in that: The droplet microfluidic chip includes a first feed hole for introducing the shell phase, a second feed hole for introducing the core phase, a third feed hole for introducing the oil phase, a first liquid flow channel connected to the first feed hole, a second liquid flow channel connected to the second feed hole, and a third liquid flow channel connected to the third feed hole, wherein the third liquid flow channel is arranged crosswise with the first liquid flow channel; the first liquid flow channel includes a first section, a second section and a third section arranged in sequence, wherein the first section and the third section are straight sections, and the second section is composed of a plurality of S-shaped bends, the third liquid flow channel is connected to the third section, and the second liquid flow channel is connected to the first section and an acute angle is formed between the two.

9. A porous core-shell hydrogel microsphere, characterized in that: The porous core-shell hydrogel microspheres are prepared by the preparation method of any one of claims 1 to 8.

10. Use of the porous core-shell hydrogel microspheres according to claim 9 in preparing cartilage repair materials and osteogenic repair materials.

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