Composite material mixed scaffold for bone repair and preparation method of composite material mixed scaffold

Abstract

The invention relates to the field of biomedical materials, in particular to a composite material mixed scaffold for bone repair and a preparation method of the composite material mixed scaffold. The method comprises the following steps: (1) taking zinc-magnesium-based alloy powder as a raw material, and obtaining a zinc-magnesium alloy stent through selective laser melting method 3D printing; (2) carrying out ball-milling mixing on bioactive glass powder and the modified mullite whiskers to obtain mixed powder, carrying out 3D printing molding on the mixed powder, and filling a zinc-magnesium alloy stent with the molded mixed powder to obtain a composite stent material; and (3) dissolving silk fibroin and breviscapine in a solvent to prepare a spinning solution, carrying out electrostatic spinning on the surface of the composite scaffold material to obtain a silk fibroin barrier membrane, and washing and drying to obtain the silk fibroin barrier membrane. Compared with magnesium alloy, the composite material mixed scaffold has the advantages that the degradation speed is obviously reduced, effective osteogenesis space support is realized, and the composite material mixed scaffold has good biocompatibility and osteogenesis efficiency.

Description

Technical Field

[0001] The present invention relates to the field of biomedical materials, and particularly to a composite structure scaffold for bone repair and a preparation method thereof. Background Art

[0002] Bone defect is a major disease faced by humans and is extremely common clinically. Currently, there are three types of bone transplantation clinically, namely autologous bone transplantation, allogeneic bone transplantation, and artificial bone transplantation. The source of autologous bone transplantation is limited and may cause secondary injury; allogeneic bone transplantation has risks such as rejection reaction and virus transmission. Currently, bone tissue engineering has gradually become one of the most promising clinical application methods for treating bone defects. An artificial bone scaffold needs to maintain an osteogenic space and gradually degrade as new bone grows in. Too fast or too slow degradation is not conducive to osteogenesis. A zinc-magnesium alloy mainly composed of zinc and added with a small amount of magnesium has the characteristic of controllable degradation, and the 3D printing process is easy to achieve. At the same time, it has excellent mechanical properties and is beneficial to the maintenance of the osteogenic space, and is considered a "revolutionary medical implant material".

[0003] Artificial bone transplantation materials not only require the material to have biocompatibility, but also need to have mechanical compatibility. A single scaffold configuration and a single material are difficult to achieve gradual degradation as new bone grows in, and it is also difficult to achieve biomechanical compatibility and the best osteogenic performance. For large bone defects, artificial bone transplantation with a composite structure scaffold is the research direction of bone tissue engineering. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, one of the purposes of the present invention is to provide a preparation method for a composite structure scaffold for bone repair, which has strong feasibility and is conducive to realizing industrial production.

[0005] Another purpose of the present invention is to provide a composite structure scaffold for bone repair. The composite structure scaffold includes a total of three-level structures. Among them, the first-level structure is a laser-melted 3D printed zinc-magnesium alloy scaffold with a porous network configuration, which has good mechanical properties and can support the osteogenic space of the defect; the second-level structure is small particles with a porous configuration filled with particles inside, which are formed by digitally light-processed 3D printing of a mixed powder of bioactive glass and modified mullite whiskers, and are stacked and interlocked as fillers for the first-level scaffold structure, having biological activity, guiding bone regeneration, and having a synergistic degradation effect while the first-level structure degrades; the third-level structure is a silk fibroin piezoelectric barrier membrane covered on the surface of the scaffold, which can shield the ingrowth of epithelial cells and fibroblast cells and promote the ingrowth of osteoblast cells into new bone tissue.

[0006] One of the purposes of the present invention is realized by adopting the following technical solution: A preparation method for a composite structure scaffold for bone repair, comprising the following steps: (1) Using zinc-magnesium-based alloy powder as raw material, a zinc-magnesium alloy scaffold is obtained by selective laser melting 3D printing; (2) Bioactive glass powder and modified mullite whiskers are ball-milled and mixed to obtain a mixed powder; the mixed powder is 3D printed into a shape to obtain filled particles, and the filled particles are filled into the zinc alloy scaffold to obtain a composite scaffold material; (3) Silk fibroin and breviscapine are dissolved in a solvent to prepare a spinning solution, and electrospinning is carried out on the surface of the composite scaffold material to form a silk fibroin barrier membrane, which is washed with water and dried to obtain the composite structure scaffold for bone repair.

[0007] Further, in step (2), the preparation method of the modified mullite whiskers is as follows: The mullite whiskers are dispersed in toluene, 3-aminopropyltriethoxysilane is added and stirred, and after washing with toluene and drying, the modified mullite whiskers are obtained.

[0008] Further, the mass ratio of the mullite whiskers to 3-aminopropyltriethoxysilane is 1:(6 - 7.5), and the stirring time is 10 - 14 h.

[0009] Further still, the diameter of the mullite whiskers in the present invention is 0.2 - 3 µm, and the length is 5 - 200 µm.

[0010] Further, in step (1), the content of magnesium element in the zinc-magnesium-based alloy powder is 0.8 - 2 wt%.

[0011] Further, in step (2), the mass ratio of the bioactive glass powder to the modified mullite whiskers is 1:(0.03 - 0.12).

[0012] Further, in step (2), the ball-milling and mixing time is 3 - 4 h.

[0013] Further, in step (2), the bioactive glass powder is composed of 58S bioactive glass and 45S bioactive glass mixed according to a mass ratio of 1:1; the particle size of the 58S bioactive glass powder is <15 µm, and the particle size of the 45S bioactive glass powder is <15 µm.

[0014] Further, in step (3), the mass fraction of silk fibroin in the spinning solution is 8 - 10%, and the mass fraction of breviscapine in the spinning solution is 0.2 - 0.5%.

[0015] Further, in step (3), the solvent is hexafluoroisopropanol.

[0016] The second object of the present invention is achieved by the following technical solution: The composite structure scaffold for bone repair described above is obtained according to the above preparation method.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention provides a composite structure scaffold for bone repair. This composite structure scaffold couples the unique advantages of multiple degradable materials and plays a coordinated role with each other, constructing a defect repair and reconstruction system from multiple perspectives and in all directions, such as mechanical fixation and support, bone mass space maintenance, osteoconduction, and barrier piezoelectric osteogenesis. The specific strategies are as follows: Firstly, the present invention adopts the laser melting method 3D printing technology, using zinc-magnesium-based alloy powder as the raw material to prepare a zinc-magnesium alloy scaffold with a porous grid structure. This 3D printing process is not only easy to implement, but also the prepared zinc-magnesium alloy scaffold exhibits excellent mechanical properties. Through the carefully designed porous grid structure, this scaffold can effectively maintain the overall macroscopic mechanical stability of the defect repair site. At the same time, the topological structure is optimized in combination with biomechanical principles, minimizing the usage amount of zinc-magnesium alloy powder, thereby reducing the ion concentration and achieving the best mechanical adaptability and biocompatibility.

[0018] Secondly, the bioactive glass selected in the present invention has excellent biocompatibility and relatively high mechanical strength, and its degradation products can promote the expression of growth factors and enhance bone tissue growth. Based on the degradability, bioactivity, and mechanical configuration design of the bioactive glass, and by adding silane-coupled mullite whiskers to improve the compatibility between components, it is assembled with the zinc-magnesium alloy scaffold to overall regulate the degradation performance of the composite structure scaffold in the in-vivo biostress environment.

[0019] In addition, the present invention also obtains a silk fibroin barrier membrane through the electrospinning method. The formed silk fibroin barrier membrane has a longer degradation period compared to the periosteum used clinically. More importantly, the breviscapine added during the film-making process can induce the conformational change of silk fibroin from random coil to β-sheet, thereby enhancing the longitudinal piezoelectric coefficient of the silk fibroin barrier membrane and strengthening its piezoelectric effect under stress response, more effectively shielding the ingrowth of epithelial cells and fibroblasts into the scaffold in the long term, strengthening the barrier effect, promoting the guided bone regeneration of the scaffold, and further enhancing the osteogenic efficiency.

[0020] 2. The present invention also provides a preparation method for the above composite structure scaffold for bone repair. This method has strong feasibility and effectively improves the material properties. Description of the Drawings

[0021] Figure 1 It is an exploded schematic diagram of the composite structure scaffold of the present invention; Figure 2Micro-CT scan result diagram obtained after implanting the composite structure scaffold of the present invention into an animal body for 3 months; Figure 3 Histological evaluation result diagram obtained after implanting the composite structure scaffold of the present invention into an animal body for 3 months; Reference numerals: 1 is a zinc-magnesium alloy scaffold, 2 is a filling particle, and 3 is a silk fibroin barrier membrane. Detailed implementation manners

[0022] Next, in combination with the accompanying drawings and specific implementation manners, the present invention will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments. Specific conditions not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are all conventional products obtained through commercial channels without special instructions.

[0023] In the present invention, the bioactive glass powder is composed of 58S bioactive glass and 45S bioactive glass mixed in a mass ratio of 1:1, wherein the particle size of the 58S bioactive glass powder is <15 μm, and the particle size of the 45S bioactive glass powder is <15 μm.

[0024] In the present invention, the diameter of the mullite whiskers is 0.2 - 3 µm, and the length is 5 - 200 µm.

[0025] The zinc-magnesium-based powder material of the present invention is prepared by the aerosol method: First, the ratio of zinc and magnesium is precisely controlled by an automatic feeding system, wherein the content of magnesium element is 1 wt%. It is rapidly melted by electromagnetic induction, the power is set to 500 kW, the frequency is 10 kHz, and the melting temperature is raised to 450 °C. After the molten metal liquid flows through the nozzle and sprays out, at the same time, high-pressure inert argon gas (oxygen content <50 ppm, gas pressure is 8 MPa, gas flow rate ≥1.5 Mach number) is sprayed out at high speed from around the nozzle to break the metal liquid flow into tiny droplets. The droplets are fully heat-exchanged with the cooling gas and quickly solidify into powder particles, and finally the powder is collected.

[0026] Preparation Example 1: A modified mullite whisker, the preparation method is as follows: According to the dosage ratio of mullite whiskers, toluene, and 3-aminopropyltriethoxysilane of 100 mg:45 mL:700 mg, the mullite whiskers are dispersed in toluene, then 3-aminopropyltriethoxysilane is added, stirred for 12 h, washed with toluene, and then vacuum-dried at 50 °C for 12 h to obtain.

[0027] Preparation Example 2: A modified mullite whisker, the preparation method is as follows: Disperse mullite whiskers in toluene according to the dosage ratio of mullite whiskers, toluene, and 3-aminopropyltriethoxysilane of 100 mg: 40 mL: 600 mg. Then add 3-aminopropyltriethoxysilane, stir for 10 h, wash with toluene, and then vacuum dry at 50 °C for 12 h to obtain.

[0028] Preparation Example 3: A method for preparing a modified mullite whisker is as follows: Disperse mullite whiskers in toluene according to the dosage ratio of mullite whiskers, toluene, and 3-aminopropyltriethoxysilane of 100 mg: 50 mL: 750 mg. Then add 3-aminopropyltriethoxysilane, stir for 14 h, wash with toluene, and then vacuum dry at 50 °C for 12 h to obtain.

[0029] Example 1: A method for preparing a composite structure scaffold for bone repair includes the following steps: (1) Under the protection of argon throughout the process, use a selective laser melting method to 3D print zinc-magnesium alloy powder (where the content of magnesium element is 1 wt%) to obtain a zinc-magnesium alloy scaffold 1. The process parameters are: laser power is 80 W, scanning speed is 110 mm / s, and printing layer thickness is 60 μm. Use this zinc-magnesium alloy scaffold 1 as the primary structure of the composite structure scaffold. (2) Under an argon atmosphere, use a ball mill to mix bioactive glass powder and the modified mullite whiskers obtained in Preparation Example 1 at a rotation speed of 250 rpm for 3.5 h to obtain a mixed powder. Among them, the mass ratio of bioactive glass powder to modified mullite whiskers is 1:0.09. Then, use DLP digital light processing technology to 3D print the mixed powder into a shape. The process parameters are: exposure time is 2.2 s, printing layer thickness is 50 μm, to obtain filling particles 2. Fill the filling particles 2 as the secondary structure into the zinc-magnesium alloy scaffold 1 to obtain a composite scaffold material. (3) Dissolve silk fibroin and breviscapine in hexafluoroisopropanol to prepare a spinning solution. Among them, the mass fraction of silk fibroin in the spinning solution is 9%, and the mass fraction of breviscapine in the spinning solution is 0.4%. Use a 10 mL glass syringe to suck 5 mL of the spinning solution and place it in an electrospinning device. In a low-vacuum environment at 40 °C, perform electrospinning on the surface of the composite scaffold material obtained in step (2). Denote the silk fibroin barrier film 3 formed on the surface of the composite scaffold material as the tertiary structure. Among them, the syringe needle model is G20, the DC voltage at the syringe needle is 15 kV, the electrospinning speed is 2.0 mL / h, and the electrospinning distance is 15 cm. Then wash the electrospun composite scaffold material 3 times with deionized water and vacuum dry to obtain the composite structure scaffold.

[0030] Example 1 also provides a composite structure scaffold for bone repair, which is prepared by the above preparation method. The schematic diagram of the structural decomposition of the bone repair composite structure scaffold is as Figure 1 shown.

[0031] Example 2: A preparation method of a composite structure scaffold for bone repair, comprising the following steps: (1) The specific steps are the same as those in Example 1; (2) Under an argon atmosphere, the bioactive glass powder and the modified mullite whiskers obtained in Preparation Example 2 are mixed for 4 h at a rotation speed of 240 rpm by a ball mill to obtain a mixed powder; wherein, the mass ratio of the bioactive glass powder to the modified mullite whiskers is 1:0.03; then, the mixed powder is 3D printed into a shape by DLP digital light processing technology, and the process parameters are: exposure time 2.2 s, printing layer thickness 50 μm, to obtain a filling particle 2; the filling particle 2 is filled into the zinc-magnesium alloy scaffold 1 as a secondary structure to obtain a composite scaffold material; (3) Dissolve silk fibroin and breviscapine in hexafluoroisopropanol to prepare a spinning solution, wherein the mass fraction of silk fibroin in the spinning solution is 8%, and the mass fraction of breviscapine in the spinning solution is 0.2%; suck 5 mL of the spinning solution with a 10 mL glass syringe, place it in an electrospinning device, and perform electrospinning on the surface of the composite scaffold material obtained in step (2) in a low vacuum environment at 40 °C. The silk fibroin barrier film 3 formed on the surface of the composite scaffold material is recorded as a tertiary structure; wherein, the syringe needle model is G20, the DC voltage at the syringe needle is 15 kV, the electrospinning speed is 2.0 mL / h, and the electrospinning distance is 15 cm; then the electrospun composite scaffold material is washed 3 times with deionized water and dried in vacuum to obtain the composite structure scaffold.

[0032] Example 2 also provides a composite structure scaffold for bone repair, which is prepared by the above preparation method.

[0033] Example 3: A preparation method of a composite structure scaffold for bone repair, comprising the following steps: (1) The specific steps are the same as those in Example 1; (2) Under an argon atmosphere, the bioactive glass powder and the modified mullite whiskers obtained in Preparation Example 3 were mixed for 3 h using a ball mill at a rotation speed of 260 rpm to obtain a mixed powder; wherein, the mass ratio of the bioactive glass powder to the modified mullite whiskers was 1:0.12; then, the mixed powder was 3D printed into shape using DLP digital light processing technology, and the process parameters were: laser power of 85 W, scanning speed of 120 mm / s, printing layer thickness of 50 μm, to obtain filling particles 2; the filling particles 2 were filled into the zinc-magnesium alloy scaffold 1 as a secondary structure to obtain a composite scaffold material; (3) Silk fibroin and breviscapine were dissolved in hexafluoroisopropanol to prepare a spinning solution; wherein, the mass fraction of silk fibroin in the spinning solution was 10%, and the mass fraction of breviscapine in the spinning solution was 0.5%; 5 mL of the spinning solution was aspirated with a 10 mL glass syringe and placed in an electrospinning device, and electrospinning was carried out on the surface of the composite scaffold material in step (2) under a low vacuum environment at 40 °C. The silk fibroin barrier membrane 3 formed on the surface of the composite scaffold material was recorded as a tertiary structure; wherein, the syringe needle model was G20, the DC voltage at the syringe needle was 15 kV, the electrospinning speed was 2.0 mL / h, and the electrospinning distance was 15 cm; then the electrospun composite scaffold material was washed 3 times with deionized water and dried in vacuo to obtain the composite material hybrid structure scaffold.

[0034] Example 3 of the present invention also provides a composite material hybrid structure scaffold for bone repair, which is prepared by the above preparation method.

[0035] Comparative Example 1: This Comparative Example 1 is basically the same as Example 1, except that: the modified mullite whiskers were omitted in step (2); the others were the same as Example 1.

[0036] Comparative Example 2: This Comparative Example 2 is basically the same as Example 1, except that: the modified mullite whiskers were replaced with mullite whiskers in step (2); the others were the same as Example 1.

[0037] Comparative Example 3: This Comparative Example 3 is basically the same as Example 1, except that: breviscapine was omitted in step (3); the others were the same as Example 1.

[0038] Test Example 1: The composite materials of Examples 1-3 and Comparative Examples 1-3 were placed in Hank's simulated body fluid at 37 °C and soaked for 500 h, and then the degradation rates of each group of samples were tested, and the unit was in millimeters per year (mm / a). The experimental results are shown in Table 1.

[0039] Table 1 Degradation rates of the composite materials obtained in Examples 1-3 and Comparative Examples 1-3 ; As can be seen from the test results in Table 1, the degradation rate of the composite material for bone repair prepared by the present invention is slow and controllable. In Comparative Example 1 and Comparative Example 2, the modified mullite whiskers are omitted and the modified mullite whiskers are replaced by mullite whiskers respectively. Finally, the degradation rate of the prepared composite material increases significantly. This shows that in addition to improving the compatibility between components, the mullite whiskers modified by silane coupling agent can also regulate the degradation rate of the composite structure scaffold.

[0040] Test Example 2: In order to test the longitudinal piezoelectric coefficient D33 of the composite materials obtained in Examples 1-3 and Comparative Examples 1-3, a quasi-static piezoelectric constant measuring instrument was used to test the longitudinal piezoelectric coefficient of the composite materials under a scanning voltage of 0-10V; the test results are shown in Table 2.

[0041] Table 2 Longitudinal piezoelectric coefficients of the composite materials obtained in Examples 1-3 and Comparative Examples 1-3 ; From the above test results, it can be seen that the longitudinal piezoelectric coefficients of the composite materials obtained in Examples 1-3 of the present invention are significantly better than those of Comparative Example 3. In Comparative Example 3, breviscapine was omitted when preparing the silk fibroin barrier membrane, and the piezoelectric coefficient decreased significantly. This shows that breviscapine can improve the longitudinal piezoelectric coefficient of the silk fibroin membrane. This may be because breviscapine can cause the conformation of silk fibroin to change from random coil to β-sheet, thereby improving the longitudinal piezoelectric coefficient of the silk fibroin barrier membrane. Therefore, through the promotion effect of breviscapine on the longitudinal piezoelectric coefficient of the silk fibroin barrier membrane, the piezoelectric effect of the composite material under stress response is enhanced, and the differentiation and proliferation of osteoblasts are stimulated, and then it can be applied to the repair of bone defects.

[0042] Test Example 3: In order to evaluate the osteogenic efficacy of the products obtained in Examples 1-3 of the present invention and Comparative Examples 1-3, an in vivo osteogenic experiment was carried out.

[0043] New Zealand white rabbits were selected as experimental animals, weighing 2.5 - 3.0 kg, provided by the Animal Experiment Science Department of Peking University Health Science Center. The above animals were randomly divided into Example 1 group, Example 2 group, Example 3 group, Comparative Example 1 group, Comparative Example 2 group, and Comparative Example 3 group. All experimental rabbits were anesthetized by inhaling isoflurane, with an induction concentration of 2% - 5% and a maintenance concentration of 1.5% - 3%. The anesthesiologist monitored the rabbits' respiration and heart rate throughout the operation. The rabbits were placed prone, and the surgical area was shaved and disinfected with 10% povidone iodine solution. A 4-cm sagittal incision was made on the scalp at the top of the skull, and the full-thickness skin flap was turned over to expose the intersection of the coronal suture and the sagittal suture. Four symmetric circular grooves with a diameter of 6 mm and a depth of about 0.5 mm were made in the middle to create cortical perforations. Then, in the corresponding groups, the products of Examples 1 - 3 and Comparative Examples 1 - 3 were respectively implanted into the grooves and vertically embedded and fixed, and the wound was closed in layers. After the operation, the experimental rabbits were intramuscularly injected with 40,000 U of penicillin per kilogram of body weight for 3 days.

[0044] (1)Skull specimens were taken 3 months after the operation, and Micro-CT scanning and reconstruction were performed to observe the volume of newly formed bone. The experimental results are as Figure 2 shown.

[0045] (2)The skull specimens taken 3 months later were made into tissue sections, and histological observations were performed after HE staining to evaluate the osteogenic effect. The results are as Figure 3 shown.

[0046] From Figure 2 the Micro-CT scan images, it can be seen that the osteogenic effects of Examples 1 - 3 are better than those of Comparative Examples 1 - 3, and a large amount of newly formed bone grows into the space of the stent particles. Among them, the number of newly formed bones in Comparative Example 3 is the least after omitting breviscapine.

[0047] From Figure 3 it can be known that: the composite materials of Examples 1 - 3 have uniform osteogenesis in vivo, and the osteogenic volume is better than that of the products of Comparative Examples 1 - 3. Among them, there is a small amount of newly formed bone tissue in Comparative Example 3, but it is less than that in Example 1 group.

[0048] The above results show that the breviscapine added during the preparation of the silk fibroin barrier membrane can cause the conformational change of silk fibroin from random coil to β-sheet, thereby enhancing the longitudinal piezoelectric coefficient of the silk fibroin barrier membrane and strengthening its piezoelectric effect under stress response. While shielding epithelial cells and fibroblasts, it can further improve the osteogenic efficiency.

[0049] The above embodiments are only the preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantive changes and substitutions made by those skilled in the art based on the present invention belong to the scope of protection required by the present invention.

Claims

1. A preparation method of a composite structure scaffold for bone repair, characterized in that, It includes the following steps: (1) Using zinc-magnesium-based alloy powder as raw material, a zinc-magnesium alloy scaffold is obtained by selective laser melting 3D printing; (2) Bioactive glass powder and modified mullite whiskers are ball-milled and mixed to obtain a mixed powder; the mixed powder is 3D printed into shape to obtain filled particles; the filled particles are filled into the zinc-magnesium alloy scaffold to obtain a composite scaffold material; (3) Silk fibroin and breviscapine are dissolved in a solvent to prepare a spinning solution, and electrospinning is carried out on the surface of the composite scaffold material to form a silk fibroin barrier film, which is washed with water and dried to obtain the composite structure scaffold for bone repair.

2. The preparation method of the composite structure scaffold for bone repair according to claim 1, wherein In step (2), the preparation method of the modified mullite whiskers is as follows: The mullite whiskers are dispersed in toluene, 3-aminopropyltriethoxysilane is added and stirred, and after washing with toluene and drying, it is obtained.

3. The preparation method of the composite structure scaffold for bone repair according to claim 2, characterized in that The mass ratio of the mullite whiskers to 3-aminopropyltriethoxysilane is 1:(6 - 7.5), and the stirring time is 10 - 14 h.

4. The preparation method of the composite structure scaffold for bone repair according to claim 1, wherein In step (1), the content of magnesium element in the zinc-magnesium-based alloy powder is 0.8 - 2 wt%.

5. The preparation method of the composite structure scaffold for bone repair according to claim 1, wherein In step (2), the mass ratio of the bioactive glass powder to the modified mullite whiskers is 1:(0.03 - 0.12).

6. The preparation method of the composite structure scaffold for bone repair according to claim 1, characterized in that, In step (2), the ball-milling and mixing time is 3 - 4 h.

7. The preparation method of the composite structure scaffold for bone repair according to claim 1, characterized in that, In step (2), the bioactive glass powder is composed of 58S bioactive glass and 45S bioactive glass mixed by mass ratio of 1:1; the particle size of the 58S bioactive glass powder < 15 μm, and the particle size of the 45S bioactive glass powder < 15 μm.

8. The preparation method of the composite structure scaffold for bone repair according to claim 1, characterized in that, In step (3), the mass fraction of silk fibroin in the spinning solution is 8 - 10%, and the mass fraction of breviscapine in the spinning solution is 0.2 - 0.5%.

9. The preparation method of the composite structure scaffold for bone repair according to claim 1, wherein In step (3), the solvent is hexafluoroisopropanol.

10. A composite structure scaffold for bone repair, characterized in that, Prepared according to the preparation method described in any one of claims 1 - 9.

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