A biodegradable scaffold that promotes the regeneration of artificial blood vessel tissue and its preparation method

Abstract

The present invention provides a degradable stent for promoting artificial vascular tissue regeneration and a method for preparing the same. The degradable stent is a three-layer tubular stent constructed from a degradable polymer. The middle layer is a nanofiber layer. The inner and outer tube walls contain a large number of micropores, which are interconnected in series and extend from the inside outward to form a beaded structure. The beaded structure extends from the lumen to the outer surface and forms microchannels for cell migration. Cells can secrete extracellular matrix within the tube wall, thereby promoting the regeneration of new tissue. At the same time, the nanofiber layer separates the microporous channels of the inner and outer layers, allowing different cells to grow in the inner and outer layers respectively. Secondly, the pores in the nanofiber layer do not allow cells to pass through, but do allow nutrients and growth factors secreted by cells to pass through, thereby promoting information exchange between cells on both sides, regulating cell behavior, and further accelerating vascular remodeling.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a biodegradable scaffold that promotes the regeneration of artificial blood vessel tissue and its preparation method. Background Technology

[0002] Cardiovascular disease (CDV) has become one of the leading causes of death worldwide, with the number of people suffering from it projected to reach 4 million by 2025. Artificial blood vessels can replace and reshape damaged natural blood vessels for procedures such as vascular replacement, bypass surgery, and fistula creation. Currently, large-diameter (inner diameter > 6 mm) artificial blood vessel stents used clinically include polyester (PET) and polytetrafluoroethylene (ePTFE) stents, primarily used for aortic aneurysm repair and aortic coarctation. However, due to the poor biocompatibility of polymer materials, they easily activate coagulation reactions, forming thrombi and causing vascular blockage. The rigid polymer materials also do not match the mechanical properties of natural blood vessels, leading to blood flow disturbances at the suture site and further increasing the risk of blockage. Due to thrombosis, both types of stents exhibit poor patency rates in the early and middle stages of implantation, making them unsuitable for fabricating small-diameter artificial blood vessel stents. Autologous transplanted blood vessels are soft and have good biocompatibility, but their availability is limited and they are not widely used. In order to obtain a biocompatible artificial vascular stent to meet the needs of small-diameter artificial blood vessels, more and more researchers are turning their attention to biodegradable materials.

[0003] Biodegradable materials, including biodegradable natural and synthetic materials, are widely used to fabricate implantable scaffolds such as heart valves, organs, and tendons due to their excellent biocompatibility. Biodegradable vascular scaffolds are typically formed using methods such as electrospinning and phase separation to obtain a uniform hollow tubular structure. However, the dense wall structure does not result in ideal endothelialization, because cells struggle to grow into the scaffold interior, and the smooth inner wall is also highly unfavorable for cell adhesion. Although electrospinning can produce a dense fiber network, the micron-sized pores do not allow for cell infiltration. This single-structure scaffold delays tissue regeneration and may trigger a series of inflammatory responses, increasing the risk of scaffold occlusion. Therefore, it is necessary to design a biodegradable scaffold that promotes the regeneration of artificial vascular tissue. Summary of the Invention

[0004] This invention provides a biodegradable scaffold for promoting the regeneration of artificial vascular tissue and its preparation method. The biodegradable scaffold has a three-layer tubular structure with numerous micropores in the inner and outer layers. These micropores are interconnected to form a beaded structure, which extends from the inside of the lumen to the outer surface, becoming a microchannel for cell migration. Cells can secrete extracellular matrix within the scaffold wall, thereby promoting the regeneration of new tissue. Simultaneously, the middle layer of the biodegradable scaffold is a nanofiber layer with certain porosity. Its function is to block but not obstruct. Firstly, it separates the microporous channels of the inner and outer layers, allowing different cells to grow separately in the inner and outer layers, compensating for the slow growth and proliferation of single cells and accelerating vascular remodeling. Secondly, while the pores in the nanofiber layer do not allow cells to pass through, they do allow nutrients and cell-secreted growth factors, such as NO and various enzymes, to pass through, thereby promoting information exchange between cells on both sides, regulating cell behavior, and further accelerating vascular remodeling.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A biodegradable scaffold that promotes the regeneration of artificial blood vessel tissue, wherein the biodegradable scaffold is a three-layer tubular scaffold constructed from biodegradable polymers, the middle layer being a nanofiber layer, and the inner and outer layers containing a large number of micropores in their tube walls, with the micropores interconnected and extending from the inside out to form a beaded structure.

[0007] The biodegradable polymers in each layer of the three-layer tubular scaffold are one or more of polycaprolactone (PCL), polylactic acid (PLA), polyglycolic acid (PGA), polylactic-co-glycolic acid (PGLA), and polyglycolic acid-lactide (PLGA), with a molecular weight of 5000-20000MW.

[0008] The inner layer of the three-layer tubular scaffold has a wall thickness of 0.2-0.4 mm, the middle layer has a wall thickness of 0.1-0.2 mm, and the outer layer has a wall thickness of 0.2-0.4 mm.

[0009] The biodegradable stent has a length of 6-20cm and an inner diameter of 0.1-3.0cm.

[0010] The maximum diameter of the micropores in the beaded structure of the outer and inner layers of the three-layer tubular scaffold is 400-600 μm, the minimum diameter of the micropores is 300-400 μm, the diameter of the connecting points between the micropores is 100-300 μm, and the porosity of the micropores is 30-60%. The pore diameter of the nanofiber layer is 10-20 μm, and the porosity of the nanofiber layer is 10-15%.

[0011] The nanofiber layer is prepared by electrospinning. The technical parameters of the electrospinning process include: extrusion speed of 2.5-3.0 mL / h, voltage of +12-20 kV, distance between needle and support of 15-20 cm, rotation speed of 700-1000 rpm, and spinning temperature of room temperature.

[0012] The shape of the micropores is one or more combinations of circles, ellipses, squares, and triangles.

[0013] This invention also provides a method for preparing a biodegradable scaffold that promotes the regeneration of artificial vascular tissue, comprising the following steps: S1, preparing a mold set; the mold includes a round tube, a round rod, a lower end cap, an upper adapter, and a lower adapter; the lower end cap is detachably connected to the lower end of the round tube; a circular hole groove is provided at the center of the side of the lower end cap near the round tube; the diameter of the circular hole groove matches the outer diameter of the round rod; the round rod is inserted into the round tube and connected to the circular hole groove of the lower end cap; one end of the upper adapter and the lower adapter can be detachably connected to the upper and lower ends of the round tube, respectively; the other end of the upper adapter and the lower adapter can be detachably connected to a syringe and a vacuum pump, respectively.

[0014] S2. Connect the lower end cap of the mold to the lower end of the round tube. Insert the round rod into the round tube and connect it to the round hole groove of the lower end cap. Then fill the gap between the round rod and the round tube with gelatin microspheres with a diameter of 10-20μm. Then place the round tube in an environment with a humidity of 60-70% and a temperature of 24-26℃ for 6-12 hours. Then place it in an environment with a humidity of 40-60% and a temperature of 26-28℃ to dry for 6-12 hours, so that the gelatin microspheres adhere to each other.

[0015] S3. Prepare a biodegradable polymer solution with a mass fraction of 5-10% using an organic solvent, and pour the biodegradable polymer solution into a syringe; connect the upper and lower adapters to the upper and lower ends of the round tube respectively, and then connect the upper and lower adapters to the syringe and the vacuum pump respectively. Turn on the vacuum pump to evacuate air, and introduce the biodegradable polymer solution into the gaps of the gelatin microspheres under negative pressure.

[0016] S4. Connect the lower end cap to the lower end of the round tube, place the round tube in an environment with a humidity of 60-70% and a temperature of 24-26℃ to cure for 24-48 hours, and then soak the round tube in distilled water for 1-3 days to remove the gelatin microspheres and residual organic solvents, and obtain a single-layer tubular scaffold with beaded micropores.

[0017] S5. Take out the single-layer tubular scaffold with beaded micropores obtained in S4 from the round rod and round tube, prepare a 20% by mass biodegradable polymer solution with organic solvent, and electrospin a layer of nanofibers on its surface to obtain a double-layer tubular scaffold.

[0018] S6. Reinsert the double-layered tubular scaffold from S5 back into the round rod and tube, and repeat the process from S2 to S4 to obtain a three-layered tubular scaffold.

[0019] The organic solvent is one or more of hexafluoroisopropanol, dioxane, dimethylformamide, dimethylacetamide, and tetrahydrofuran.

[0020] The gelatin microspheres are prepared by microfluidic technology from a gelatin aqueous solution with a mass fraction of 2-4%.

[0021] Compared with the prior art, the beneficial effects of the present invention are: (1) The biodegradable scaffold for promoting the regeneration of artificial blood vessel tissue provided by the present invention is a three-layer tubular scaffold structure. There are a large number of micropores in the inner and outer tube walls. The micropores are connected to each other to form a beaded structure. The beaded structure extends from the inside of the tube to the outer surface and becomes a microchannel for cell migration inward. Cells can secrete extracellular matrix in the tube wall, thereby achieving the purpose of promoting the regeneration of new tissue.

[0022] (2) The middle layer of the biodegradable scaffold in this invention is a nanofiber layer with certain pores, which can separate the micropore channels of the inner and outer layers, allowing different cells to grow in the inner and outer layers respectively, making up for the defect of slow growth and proliferation of single cells, and further accelerating vascular remodeling. Secondly, the pores on the nanofiber layer allow information exchange between cells, further regulating cell behavior and accelerating vascular remodeling.

[0023] (3) In this invention, the gelatin microspheres that are bonded together form a beaded channel in a biodegradable polymer. The gelatin can be dissolved at 30°C, which is convenient for creating pores. Moreover, the gelatin has good biocompatibility, is non-toxic and biodegradable. Even if the gelatin cannot be completely removed during the preparation of the scaffold, the gelatin will degrade over time after the scaffold is implanted.

[0024] (4) The present invention prepares a biodegradable scaffold using a specially made mold. The preparation method is simple, and the mold structure is simple and the manufacturing cost is low. Attached Figure Description

[0025] Figure 1 A schematic diagram of the structure of the biodegradable scaffold for promoting the regeneration of artificial blood vessel tissue provided by the present invention;

[0026] Figure 2 A flowchart illustrating the method for preparing a biodegradable scaffold that promotes the regeneration of artificial blood vessel tissue provided by the present invention;

[0027] Figure 3 Electron micrograph of the biodegradable scaffold for promoting the regeneration of artificial blood vessel tissue provided by the present invention;

[0028] Figure 4 These are confocal stained images of the biodegradable scaffold used in this embodiment;

[0029] In the diagram: 1-round tube, 2-round rod, 3-lower end cap, 4-upper adapter, 5-lower adapter, 6-syringe. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] The biodegradable scaffold structure for promoting the regeneration of artificial blood vessel tissue provided by this invention is as follows: Figure 1 As shown, the biodegradable scaffold is a three-layer tubular scaffold constructed from biodegradable polymers. Specifically, each layer of the three-layer tubular scaffold uses one or more of the following biodegradable polymers: polycaprolactone, polylactic acid, polyglycolic acid, polylactic-co-glycolic acid, and polyglycolic acid-lactide, with a molecular weight of 5000-20000 MW. Further, the length of the biodegradable scaffold is 6-20 cm, and the inner diameter is 0.1-3.0 cm. The inner layer wall thickness is 0.2-0.4 mm, the middle layer wall thickness is 0.1-0.2 mm, and the outer layer wall thickness is 0.2-0.4 mm.

[0032] In this embodiment, the middle layer of the three-layer tubular scaffold is a nanofiber layer. The inner and outer tubular walls contain numerous micropores, which are interconnected and extend from the inside out to form a beaded structure. Figure 1 This structure promotes cell migration inward and secretion of extracellular matrix within the lumen, thereby accelerating tissue regeneration. The nanofiber layer separates the inner and outer porous structures, allowing different cells to grow separately in the inner and outer layers. This multicellular growth of the scaffold further promotes vascular remodeling. Furthermore, the pores in the nanofiber layer allow for intercellular communication, further regulating cell behavior and accelerating vascular remodeling. Specifically, the multicellular components include one or more of the following: endothelial cells (HUVEC cells), smooth muscle cells (SMC cells), fibroblasts, and mesenchymal stem cells (MSCs). Figure 1 Endothelial cells mainly grow on the inner wall of the tube, while smooth muscle cells mainly grow on the outer wall.

[0033] Specifically, the micropores are shaped as one or more combinations of circles, ellipses, squares, and triangles. Further, the porosity of the micropores in the outer and inner layers of the three-layer tubular scaffold is 30-60%, and the porosity of the nanofiber layer is 10-15%. Preferably, the maximum diameter of the micropores at the beaded structure of the outer and inner layers of the three-layer tubular scaffold is 400-600 μm, the minimum diameter of the micropores is 300-400 μm, the diameter of the interconnected micropores is 100-300 μm, and the pore diameter of the nanofiber layer is 10-20 μm.

[0034] This invention also provides a method for preparing a biodegradable scaffold that promotes the regeneration of artificial vascular tissue, such as... Figure 2 As shown, the process includes the following steps: S1, Prepare a set of molds;

[0035] See mold structure Figure 2 The mold includes a round tube 1, a round bar 2, a lower end cap 3, an upper adapter 4, and a lower adapter 5. The lower end cap is detachably connected to the lower end of the round tube. In actual installation, the lower end cap is connected to the lower end of the round tube by interference fit or thread. A circular hole groove (not shown in the figure) is provided at the center of the side of the lower end cap near the round tube. The diameter of the circular hole groove matches the outer diameter of the round bar. The round bar is inserted into the round tube and connected to the circular hole groove of the lower end cap. See Figure 2 This allows the round rod and the round tube to be coaxially connected; one end of the upper and lower conversion joints can be detachably connected to the upper and lower ends of the round tube. In actual installation, the upper and lower conversion joints can also be connected to the upper and lower ends of the round tube by interference fit or thread; the other end of the upper and lower conversion joints can be detachably connected to the syringe 6 and the vacuum pump, respectively; specifically, the round tube is a stainless steel tube, and the round rod is made of polytetrafluoroethylene material.

[0036] S2. Connect the lower end cap of the mold to the lower end of the round tube. Insert the round rod into the round tube and connect it to the round hole groove of the lower end cap. Then fill the gap between the round rod and the round tube with gelatin microspheres with a diameter of 10-20μm. Place the round tube in an environment with a humidity of 60-70% and a temperature of 24-26℃ (high humidity environment) for 6-12 hours to allow the gelatin microspheres to adhere using the moisture in the air. Then place it in an environment with a humidity of 40-60% and a temperature of 26-28℃ to dry for 6-12 hours to allow the gelatin microspheres to adhere to each other.

[0037] Specifically, the gelatin microspheres are prepared by microfluidic technology from a gelatin aqueous solution with a mass fraction of 2-4%.

[0038] S3. Prepare a biodegradable polymer solution with a mass fraction of 5-10% using an organic solvent, and pour the biodegradable polymer solution into the syringe; remove the lower end cap, connect the upper and lower adapters to the upper and lower ends of the round tube respectively, and then connect the upper and lower adapters to the syringe and the vacuum pump respectively. Turn on the vacuum pump to evacuate air, and introduce the biodegradable polymer solution into the gaps of the gelatin microspheres under negative pressure.

[0039] Specifically, the organic solvent is one or more of hexafluoroisopropanol, dioxane, dimethylformamide, dimethylacetamide, and tetrahydrofuran;

[0040] S4. Remove the upper and lower adapters, connect the lower end cap to the lower end of the round tube, place the round tube in an environment with a humidity of 60-70% and a temperature of 24-26℃ to cure for 24-48 hours, and then soak the round tube in distilled water for 1-3 days to remove the gelatin microspheres and residual organic solvents, and obtain a single-layer tubular scaffold with beaded micropores.

[0041] S5. Take out the single-layer tubular scaffold with beaded micropores obtained in S4 from the round rod and round tube, prepare a 20% by mass biodegradable polymer solution with organic solvent, and electrospin a layer of nanofibers on its surface to obtain a double-layer tubular scaffold.

[0042] Specifically, the technical parameters of the nanofiber layer include: extrusion speed of 2.5-3.0 mL / h, voltage of +12-20 kV, distance between needle and support of 15-20 cm, rotation speed of 700-1000 rpm, and spinning temperature of room temperature;

[0043] S6. Reinsert the double-layered tubular support from S5 back into the round rod and tube, and repeat the process from S2 to S4 to obtain a three-layered tubular support. The diameter of the round tube used in this step is larger than that of the round tube in step S2, and the sizes of the matching lower end cap, upper adapter, and lower adapter are also different, thus obtaining a three-layered tubular support of the required thickness.

[0044] The electron micrograph of the biodegradable scaffold prepared in this embodiment is shown below. Figure 3 As shown, the pores inside the support are relatively evenly distributed and of appropriate size.

[0045] The biodegradable scaffold prepared in this embodiment was used in an in vitro experiment. The experimental steps were as follows:

[0046] 1. Cell seeding: Cut the biodegradable scaffold into 3cm pieces, sterilize with alcohol overnight, and wash with PBS; culture the cells in culture dishes, and after the confluence reaches 80% or more, digest with 0.25% trypsin, resuspend in the culture medium, and seed with 1*10 7 The cells / ml density was seeded on the surface and lumen of the biodegradable scaffold;

[0047] 2. Perfusion culture: After the cells adhered for 4 hours, the sample was connected to the perfusion system and the scaffold was cultured in a dynamic environment for 7 days. The perfusion fluid flow rate was 1000 μl / min (i.e. the flow rate of the culture medium inside the scaffold) to simulate the real human vascular microenvironment.

[0048] 3. Sample fixation and dehydration: After 7 days of dynamic culture, the scaffold was removed from the perfusion system and soaked in paraformaldehyde for fixation overnight; then soaked in 30% sucrose solution for dehydration overnight; and then soaked in 40% sucrose solution for dehydration overnight.

[0049] 4. Cryosectioning: After absorbing the moisture from the sample surface, OCT embedding is performed. A 100μm thick section is cut using a cryostat (note that this is a cross-section of the sample). The sample is then stained and mounted using a glass slide.

[0050] 5. Cell Staining: Use an immunohistochemical pen to delineate the sample area on a glass slide to prevent leakage of the staining solution during the staining process. Add 0.3% Triton to permeate the cell membrane, treat for 15 min and then discard, wash with PBS; prepare RFITC staining working solution (10 μl stock solution + 2 ml 3% BSA), add it to the sample, incubate in the dark for 30 min and then discard, wash with PBS; incubate with DAPI working solution in the dark for 5 min and then discard, wash with PBS; add anti-fluorescence quencher, cover with a glass slide, and seal with nail polish around the edges;

[0051] 6. Confocal Imaging: Invert the slide in the fluorescence microscope, adjust the focus and brightness, select the desired field of view and magnification, take the picture, and save the results. Figure 4 As shown.

[0052] The cells used in this embodiment were endothelial cells, approximately 60 μm in size. The tandem pores within the scaffold ranged from 100-300 μm. Confocal staining images demonstrated that the cells adhered and spread along the inner walls of the pores, essentially covering the entire pore surface, and migrated to considerable depths. This is a result of surface-adhered cells migrating inwards, proving that cells can grow on the scaffold surface and migrate inwards. In the initial seeding stage, cells adhered only to the surface of the scaffold lumen. After 7 days of dynamic culture, under the influence of osmotic pressure from the tube wall, the cells were propelled into the scaffold interior. The pores on the scaffold surface provided suitable space and microenvironment to accommodate the migrating cells, and the tandem structure of the pores within the tube wall further accelerated the overall cellularization of the scaffold, as cells could infiltrate deeper into the scaffold. Moreover, during cell infiltration, no scaffold degradation or other special treatments to create pores were required, thus not reducing the mechanical properties of the scaffold after long-term implantation.

Claims

1. A biodegradable scaffold that promotes the regeneration of artificial vascular tissue, characterized in that: The biodegradable scaffold is a three-layer tubular scaffold constructed from biodegradable polymers. The middle layer is a nanofiber layer. The inner and outer layers contain a large number of micropores in their tube walls, and the micropores are interconnected and extend from the inside to the outside to form a beaded structure. The maximum diameter of the micropores in the beaded structure of the outer and inner layers is 400-600 μm, the minimum diameter of the micropores is 300-400 μm, the diameter of the interconnected micropores is 100-300 μm, and the pore diameter of the nanofiber layer is 10-20 μm.

2. The biodegradable scaffold for promoting the regeneration of artificial blood vessel tissue according to claim 1, characterized in that: The biodegradable polymers in each layer of the three-layer tubular scaffold are one or more of polycaprolactone, polylactic acid, polyglycolic acid, polylactic-co-glycolic acid, and polyglycolic acid-lactide, with a molecular weight of 5000-20000MW.

3. The biodegradable scaffold for promoting the regeneration of artificial blood vessel tissue according to claim 1, characterized in that: The inner layer of the three-layer tubular scaffold has a wall thickness of 0.2-0.4 mm, the middle layer has a wall thickness of 0.1-0.2 mm, and the outer layer has a wall thickness of 0.2-0.4 mm.

4. The biodegradable scaffold for promoting the regeneration of artificial blood vessel tissue according to claim 1, characterized in that: The biodegradable stent has a length of 6-20cm and an inner diameter of 0.1-3.0cm.

5. The biodegradable scaffold for promoting the regeneration of artificial blood vessel tissue according to claim 1, characterized in that: The porosity of the micropores in the beaded structure of the outer and inner layers of the three-layer tubular scaffold is 30-60%, and the porosity of the nanofiber layer is 10-15%.

6. The biodegradable scaffold for promoting the regeneration of artificial blood vessel tissue according to claim 1, characterized in that: The nanofiber layer is prepared by electrospinning. The technical parameters of the electrospinning process include: extrusion speed of 2.5-3.0 mL / h, voltage of +12-20 kV, distance between needle and support of 15-20 cm, rotation speed of 700-1000 rpm, and spinning temperature of room temperature.

7. The biodegradable scaffold for promoting the regeneration of artificial blood vessel tissue according to claim 1, characterized in that: The shape of the micropores is one or more combinations of circles, ellipses, squares, and triangles.

8. A method for preparing a biodegradable scaffold for promoting the regeneration of artificial vascular tissue according to any one of claims 1-7, characterized in that... Includes the following steps: S1. Prepare a set of molds; the mold includes a round tube, a round rod, a lower end cap, an upper adapter, and a lower adapter. The lower end cap is detachably connected to the lower end of the round tube. A circular hole groove is provided at the center of the side of the lower end cap near the round tube. The diameter of the circular hole groove matches the outer diameter of the round rod. The round rod is inserted into the round tube and connected to the circular hole groove of the lower end cap. One end of the upper adapter and the lower adapter can be detachably connected to the upper and lower ends of the round tube, respectively. The other end of the upper adapter and the lower adapter can be detachably connected to a syringe and a vacuum pump, respectively. S2. Connect the lower end cap of the mold to the lower end of the round tube. Insert the round rod into the round tube and connect it to the round hole groove of the lower end cap. Then fill the gap between the round rod and the round tube with gelatin microspheres with a diameter of 10-20μm. Then place the round tube in an environment with a humidity of 60-70% and a temperature of 24-26℃ for 6-12 hours. Then place it in an environment with a humidity of 40-60% and a temperature of 26-28℃ to dry for 6-12 hours, so that the gelatin microspheres adhere to each other. S3. Prepare a biodegradable polymer solution with a mass fraction of 5-10% using an organic solvent, and pour the biodegradable polymer solution into a syringe; connect the upper and lower adapters to the upper and lower ends of the round tube respectively, and then connect the upper and lower adapters to the syringe and the vacuum pump respectively. Turn on the vacuum pump to evacuate air, and introduce the biodegradable polymer solution into the gaps of the gelatin microspheres under negative pressure. S4. Connect the lower end cap to the lower end of the round tube, place the round tube in an environment with a humidity of 60-70% and a temperature of 24-26℃ to cure for 24-48 hours, and then soak the round tube in distilled water for 1-3 days to remove the gelatin microspheres and residual organic solvents, and obtain a single-layer tubular scaffold with beaded micropores. S5. Take the single-layer tubular scaffold with beaded micropores obtained in S4 out of the round rod and round tube, prepare a 20% by mass biodegradable polymer solution with organic solvent, and electrospin a layer of nanofibers on its surface to obtain a double-layer tubular scaffold. S6. Insert the double-layer tubular support obtained in S5 back into the round tube, and repeat the process of S2-S4 to obtain a three-layer tubular support. The diameter of the round tube used in this step is larger than the diameter of the round tube in step S2, and the sizes of the matching lower end cap, upper adapter and lower adapter are also different.

9. The method for preparing a biodegradable scaffold for promoting the regeneration of artificial blood vessel tissue according to claim 8, characterized in that: The organic solvent is one or more of hexafluoroisopropanol, dioxane, dimethylformamide, dimethylacetamide, and tetrahydrofuran.

10. The method for preparing a biodegradable scaffold for promoting the regeneration of artificial blood vessel tissue according to claim 8, characterized in that: The gelatin microspheres are prepared by microfluidic technology from a gelatin aqueous solution with a mass fraction of 2-4%.

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