Degradable biological scaffold material as well as preparation method and application thereof

Abstract

The invention discloses a degradable biological scaffold material as well as a preparation method and application thereof, and belongs to the technical field of preparation of tissue engineering materials. The preparation method of the biological scaffold material comprises the following steps: (1) taking a magnesium ingot, a gallium ingot and MgO powder as raw materials, and carrying out hot extrusion and femtosecond laser engraving to obtain the scaffold material; and (2) covering the surface of the scaffold material with a polylactic acid-gelatin magnesium ion composite coating by adopting an electrostatic spinning method, and finally coating with a polydopamine emulsion to obtain the degradable biological scaffold material. The degradable biological scaffold material prepared by the invention has good mechanical properties, a proper degradation rate and an effect of promoting osteogenic differentiation, and can be applied to bone tissue repair.

Description

Technical Field

[0001] The present invention belongs to the technical field of tissue engineering material preparation, and in particular relates to a degradable biological scaffold material and a preparation method and application thereof. Background Art

[0002] Tissue engineering is an emerging discipline that integrates engineering and life sciences. It aims to repair, maintain, or improve the function of tissues and organs by constructing biological substitutes. Its fundamental principle is to combine seed cells with biological scaffold materials to construct tissues or organs with a defined structure and function in vitro. These structures are then transplanted into the body to promote tissue regeneration and repair. Since its introduction in the late 1980s, tissue engineering has made significant progress, providing new insights and approaches to address the clinical challenges of treating tissue and organ defects.

[0003] Traditional homogeneous porous scaffolds are usually designed with a single material and a uniform pore structure. In load-bearing areas, such as bone tissue repair, the compressive strength of such scaffolds often cannot meet the requirements of physiological loads. Due to the uniformity of its pore structure, when subjected to pressure, the stress distribution is uneven, which can easily lead to local stress concentration, causing microfractures in the scaffold. Microfractures not only affect the mechanical stability of the scaffold, but may also stimulate an inflammatory response in the surrounding tissues, hindering tissue repair and regeneration. For example, in bone defect repair, traditional porous polymer scaffolds may deform and rupture when bearing the weight of the human body, and cannot provide effective mechanical support for the growth of bone tissue.

[0004] Traditional homogeneous porous scaffolds often find it difficult to achieve an ideal balance between mechanical properties and degradation rate. On the one hand, in order to improve the mechanical properties of the scaffold, it is usually necessary to increase the density of the material or reduce the porosity, but this will slow down the degradation rate of the scaffold, affecting tissue growth and repair. On the other hand, in order to speed up the degradation rate of the scaffold, it is necessary to increase the porosity or select materials with faster degradation rates, but this will reduce the mechanical properties of the scaffold, making it unable to withstand physiological loads during the tissue repair process. For example, some porous scaffolds made of degradable polymer materials have good mechanical properties in the early stages of degradation, but as degradation proceeds, their mechanical properties decline rapidly, and they cannot maintain stable mechanical support throughout the tissue repair process.

[0005] As a biodegradable metal material, magnesium alloy has excellent mechanical properties and biocompatibility, and has potential application prospects in bone tissue engineering. However, magnesium alloys undergo corrosion and degradation in the body, producing hydrogen (H2). During the degradation process, if the hydrogen is produced too quickly and the body cannot absorb and excrete it in time, it will cause hydrogen to accumulate in the surrounding tissues, forming bubbles. These bubbles will compress the surrounding tissues, affecting the tissue's blood circulation and nutrient supply, and triggering an inflammatory response. The inflammatory response not only affects tissue repair and regeneration, but can also lead to implant loosening and failure. For example, in the clinical application of magnesium alloy bone implants, some patients experience symptoms such as local swelling and pain, which are closely related to the inflammatory response caused by hydrogen accumulation.

[0006] Similar to traditional homogeneous porous scaffolds, traditional magnesium alloy scaffolds also face the problem of balancing mechanical properties and degradation rates in bone repair applications. The degradation rate of magnesium alloys is affected by many factors, such as alloy composition, tissue structure, surface treatment, etc. During the bone tissue repair process, the scaffold needs to have sufficient mechanical properties in the early stages to withstand physiological loads. At the same time, as the tissue gradually grows and repairs, the scaffold needs to be able to gradually degrade to provide space for the formation of new bone tissue. However, the degradation rate of traditional magnesium alloy scaffolds is often too fast or too slow to match the growth rate of bone tissue. If the degradation rate of the magnesium alloy scaffold is too fast, the mechanical properties of the scaffold will drop significantly before the bone tissue has fully grown and repaired, leading to implant failure. If the degradation rate is too slow, the scaffold will remain in the body for a long time, affecting the normal metabolism and growth of bone tissue.

[0007] Therefore, the present invention develops a degradable bioscaffold material and its preparation method and application, which are used to solve the technical problems in the prior art that traditional homogeneous porous scaffolds have insufficient compressive strength in the load-bearing area, are prone to microfractures, and that magnesium degradation in traditional magnesium alloys produces H2 gas accumulation that causes inflammation, and that it is difficult to balance mechanical properties and degradation rate in bone repair applications. Summary of the Invention

[0008] The purpose of the present invention is to provide a degradable bioscaffold material and its preparation method and application, which are used to solve the technical problems in the prior art that traditional homogeneous porous scaffolds have insufficient compressive strength in the load-bearing area and are prone to microfractures, and that the magnesium in traditional magnesium alloys degrades to produce H2 gas accumulation that causes inflammation, and that it is difficult to balance mechanical properties and degradation rate in bone repair applications.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions: The preparation method of the degradable biological scaffold material comprises the following steps: (1) Using magnesium ingot, gallium ingot and MgO powder as raw materials, the scaffold material is obtained by hot extrusion and femtosecond laser engraving; (2) The surface of the scaffold material is covered with a polylactic acid-gelatin magnesium ion composite coating by electrospinning, and finally coated with a polydopamine emulsion to obtain a degradable biological scaffold material.

[0010] Furthermore, step (1) specifically includes the following process: S1. Mixing magnesium ingot, gallium ingot and MgO powder, performing vacuum arc melting, and cooling to obtain magnesium alloy billet; S2. Heating the magnesium alloy billet and hot extruding it to obtain a rod; and performing femtosecond laser engraving of gradient holes on the rod to obtain a stent material; Preferably, the mass ratio of magnesium ingot, gallium ingot and MgO powder in S1 is (96-97): (2.9-3.2): (0.4-0.5), the stirring speed is 150-180 rpm, the stirring time is 20-30 min, and the vacuum is evacuated to a vacuum degree of ≤10 during vacuum arc melting. - 3 Pa, argon is introduced as a protective gas; the melting temperature is 740-760 ° C, the melting time is 45-60 min, and the cooling adopts a water-cooled copper mold at a cooling rate of >100 ° C / s.

[0011] Preferably, the heating temperature in S2 is 380-390°C, the heating rate is 15-16°C / min, the extrusion ratio during hot extrusion is 10-12:1, and the diameter of the rod is Φ4-4.2mm; the wavelength of femtosecond laser engraving is 1030-1050nm, the pulse energy is 2-2.2mJ, and the scanning speed is 280-300mm / s; the pore size gradient of the gradient hole is: outer layer (pressure-bearing area): pore size 90-100μm, porosity 30-32%; transition layer: pore size 280-300μm, porosity 48-50%, core layer (vascular area): pore size 480-500μm, porosity 69-70%, the depth of the microgroove is 8-10μm, and the spacing is 48-50μm, which is used to enhance cell adhesion.

[0012] Furthermore, step (2) specifically includes the following process: Q1. Place corn oil in a stirring container and stir while adding a gelatin magnesium solution dropwise and continue stirring to obtain an emulsion; freeze the emulsion and add a glutaraldehyde solution for cross-linking to obtain magnesium ion gelatin microspheres; Q2, adding magnesium ion gelatin microspheres to a polylactic acid solution, ultrasonically treating the solution to obtain a spinning solution, loading the spinning solution into a syringe of an electrospinning device, and electrospinning the stent material to obtain a composite coated stent; Q3. Immersing the composite coated stent in a dopamine hydrochloride solution, shaking, removing, rinsing, and drying to obtain a degradable bioscaffold material; Preferably, the volume ratio of corn oil to gelatin magnesium solution in Q1 is (4-4.1):1; the gelatin magnesium solution is prepared by adding gelatin to deionized water, stirring and dissolving in a 50-55°C water bath, adding MgCl2·6H2O solid, and stirring and dissolving to obtain the gelatin magnesium solution, wherein the amount ratio of gelatin, MgCl2·6H2O solid, and deionized water is (10-12) g:0.1 mmol:100 mL; the stirring speed is 800-900 rpm, and the stirring time is continued for 5-10 minutes; the concentration of the glutaraldehyde solution is 0.5-0.6wt%; the freezing temperature is -20°C±2°C, the freezing time is 2-3 hours, the cross-linking reaction time is 30-40 minutes, and the particle size of the magnesium ion gelatin microspheres is 5-10 μm.

[0013] Preferably, the mass ratio of magnesium ion gelatin microspheres and polylactic acid solution in Q2 is (3-3.5):100, and the ultrasonic treatment time is 30-40 min; the polylactic acid solution is obtained by dissolving polylactic acid in hexafluoroisopropanol and stirring and dissolving, wherein the concentration of the polylactic acid solution is 7-7.5wt%, the stirring temperature is 40-42°C, the stirring time is 6-8h, and the stirring speed is 100-150rpm; the average relative molecular mass of the polylactic acid is 100kDa; the electrospinning voltage is 15-18kV, the receiving distance is 15-15.5cm, the propulsion rate is 1-1.2ml / h, the electrospinning temperature is 5±2°C, the electrospinning humidity RH is less than 30%, and the composite coating thickness is 100±10μm.

[0014] Preferably, the dopamine hydrochloride solution in Q3 is prepared by dissolving dopamine hydrochloride in Tris-HCl buffer at pH = 8.5, and the concentration of the dopamine hydrochloride solution is 2-2.2 mg / mL; the oscillation temperature is 37°C ± 0.5°C, the oscillation speed is 60-80 rpm, and the oscillation time is 2-3 hours; the mixture is rinsed with ultrapure water 2-3 times, and the drying temperature is 40-42°C, and the drying time is 24-26 hours.

[0015] Furthermore, the application of degradable biological scaffold materials in bone tissue repair.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention prepares a magnesium alloy stent using magnesium ingots, gallium ingots, and MgO powder. The stent surface is coated with a polylactic acid-gelatin magnesium ion composite coating using electrospinning, and finally coated with a polydopamine emulsion to produce a degradable bioscaffold material. The magnesium alloy exhibits excellent mechanical properties, with strength and toughness sufficient to support diverse tissues. During bone tissue repair, the degradation products of the bioscaffold material can be metabolized or excreted by the body, avoiding the risk and pain of a secondary surgical procedure to remove the stent, thus reducing the burden on the patient. Furthermore, the bioscaffold material itself exhibits excellent biocompatibility and interacts well with surrounding tissues, reducing immune responses and inflammation, and providing a suitable microenvironment for tissue repair and regeneration.

[0017] 2. The polylactic acid-gelatin magnesium ion composite coating prepared by electrospinning in this invention can form a nanofibrous structure resembling the extracellular matrix, mimicking the extracellular matrix. The nanofibrous structure has a high specific surface area and porosity, providing an optimal environment for cell adhesion, proliferation, and migration, promoting cell growth and tissue repair. The magnesium ion-containing gelatin microspheres encapsulated in the coating can serve as drug carriers, enabling sustained drug release. The biological activity of magnesium ions can promote cellular function. Furthermore, the microspheres can be loaded with other drugs, such as growth factors and antibiotics. By controlling the degradation rate of the microspheres, sustained drug release can be achieved, enhancing therapeutic efficacy. Furthermore, polydopamine exhibits excellent biocompatibility, adhesion, and antibacterial properties. Polydopamine coating can improve the surface properties of scaffold materials, enhance adhesion to surrounding tissues, promote cell adhesion and growth, inhibit bacterial adhesion and growth, reduce the risk of infection, and improve the safety of scaffold implantation. Degradable bioscaffold materials not only provide sufficient mechanical support but also promote bone tissue growth and healing. Therefore, degradable bioscaffold materials are suitable for bone tissue repair. DETAILED DESCRIPTION

[0018] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0019] Example 1: This embodiment discloses a method for preparing a degradable biological scaffold material, comprising the following steps: (1) Using magnesium ingot, gallium ingot and MgO powder as raw materials, the scaffold material is obtained by hot extrusion and femtosecond laser engraving; (2) The surface of the scaffold material is covered with a polylactic acid-gelatin magnesium ion composite coating by electrospinning, and finally coated with a polydopamine emulsion to obtain a degradable biological scaffold material.

[0020] Among them, step (1) specifically includes the following process: S1. 96 g of magnesium ingot, 2.9 g of gallium ingot and 0.4 g of MgO powder were stirred and mixed at a stirring speed of 150 rpm for 20 min, and vacuum arc melting was performed. Vacuum was evacuated and argon was introduced as a protective gas. The melting temperature was 740° C. and the melting time was 45-60 min. The mixture was cooled in a water-cooled copper mold to obtain a magnesium alloy billet. S2. The magnesium alloy billet was heated to 380°C at a heating rate of 15°C / min and hot extruded at an extrusion ratio of 10:1 to obtain a rod with a diameter of Φ4 mm. The rod was then femtosecond laser engraved with gradient holes at a wavelength of 1030 nm, a pulse energy of 2 mJ, and a scanning speed of 280 mm / s. The pore size gradient of the gradient holes was as follows: outer layer (pressure-bearing area): pore size 90 μm, porosity 30%; transition layer: pore size 280 μm, porosity 48%; core layer (vascular area): pore size 480 μm, porosity 69%, microgrooves with a depth of 8 μm and a spacing of 48 μm, to obtain a stent material. Among them, step (2) specifically includes the following process: Q1. Place 400 mL of corn oil in a stirring container and stir. Simultaneously, add 100 mL of gelatin magnesium solution dropwise. The gelatin magnesium solution is prepared by adding gelatin to deionized water, stirring and dissolving in a 50°C water bath, adding MgCl2·6H2O solid, and stirring and dissolving to obtain a gelatin magnesium solution, wherein the amount ratio of gelatin, MgCl2·6H2O solid, and deionized water is 10 g:0.1 mmol:100 mL; stirring at 800 rpm, and continuing stirring for 5 minutes to obtain an emulsion; freezing the emulsion at a freezing temperature of -22°C for 2 hours, adding 0.5 wt% glutaraldehyde solution for cross-linking reaction, and the cross-linking reaction time is 30 minutes to obtain magnesium ion gelatin microspheres; Q2. 30 g of magnesium ion gelatin microspheres were added to 1 L of a 7 wt % polylactic acid solution, wherein the polylactic acid solution was dissolved in hexafluoroisopropanol and stirred at 40° C., for 6 hours, and at a speed of 100 rpm. The average relative molecular mass of the polylactic acid was 100 kDa. The spinning solution was ultrasonically treated for 30 minutes to obtain a spinning solution, which was loaded into a syringe of an electrospinning apparatus and electrospun on a scaffold material at an electrospinning voltage of 15 kV, a receiving distance of 15 cm, a propulsion rate of 1 ml / h, and an electrospinning temperature of 3° C. to obtain a composite coated scaffold. Q3. Immerse the composite coated stent in a 2 mg / mL dopamine hydrochloride solution, wherein the dopamine hydrochloride solution is prepared by dissolving dopamine hydrochloride in a Tris-HCl buffer solution at pH = 8.5, and oscillate at a temperature of 36.5°C, a speed of 60 rpm, and a time of 2 hours. Remove and rinse with ultrapure water twice, and dry at a temperature of 40°C and a time of 24 hours to obtain a degradable bioscaffold material.

[0021] Example 2: This embodiment discloses a method for preparing a degradable biological scaffold material, comprising the following steps: (1) Using magnesium ingot, gallium ingot and MgO powder as raw materials, the scaffold material is obtained by hot extrusion and femtosecond laser engraving; (2) The surface of the scaffold material is covered with a polylactic acid-gelatin magnesium ion composite coating by electrospinning, and finally coated with a polydopamine emulsion to obtain a degradable biological scaffold material.

[0022] Among them, step (1) specifically includes the following process: S1. 96.5 g of magnesium ingot, 3 g of gallium ingot and 0.45 g of MgO powder were stirred and mixed at a stirring speed of 160 rpm for 25 min, and vacuum arc melting was performed. Vacuum was evacuated and argon was introduced as a protective gas. The melting temperature was 750° C. and the melting time was 50 min. The mixture was cooled in a water-cooled copper mold to obtain a magnesium alloy billet. S2. The magnesium alloy billet was heated to 385°C at a heating rate of 15.5°C / min and hot extruded at an extrusion ratio of 11:1 to obtain a rod with a diameter of Φ4.1 mm. The rod was then femtosecond laser engraved with gradient holes at a wavelength of 1040 nm, a pulse energy of 2.1 mJ, and a scanning speed of 290 mm / s. The pore size gradient of the gradient holes was as follows: outer layer (pressure-bearing zone): pore size 95 μm, porosity 31%; transition layer: pore size 290 μm, porosity 49%; core layer (vascular zone): pore size 490 μm, porosity 69%, microgrooves with a depth of 9 μm and a spacing of 49 μm, to obtain a stent material. Among them, step (2) specifically includes the following process: Q1. Place 405 mL of corn oil in a stirring container and stir. Simultaneously, add 100 mL of gelatin magnesium solution dropwise. The gelatin magnesium solution is prepared by adding gelatin to deionized water, stirring and dissolving in a 53°C water bath, adding MgCl2·6H2O solid, and stirring and dissolving to obtain a gelatin magnesium solution, wherein the amount ratio of gelatin, MgCl2·6H2O solid, and deionized water is 11 g:0.1 mmol:100 mL; stirring at 850 rpm, and continuing stirring for 7 minutes to obtain an emulsion; freezing the emulsion at a freezing temperature of -20°C for 2.5 hours, adding 0.55 wt% glutaraldehyde solution for cross-linking reaction, and the cross-linking reaction time is 35 minutes to obtain magnesium ion gelatin microspheres; Q2. 33 g of magnesium ion gelatin microspheres were added to 1 L of a 7.3 wt % polylactic acid solution, wherein the polylactic acid solution was dissolved in hexafluoroisopropanol and stirred at 41° C., for 7 hours, and at a speed of 130 rpm. The average relative molecular mass of the polylactic acid was 100 kDa. The ultrasonic treatment was performed for 35 minutes to obtain a spinning solution, which was loaded into a syringe of an electrospinning apparatus and electrospun on a scaffold material at an electrospinning voltage of 17 kV, a receiving distance of 1.3 cm, a propulsion rate of 1.1 ml / h, and an electrospinning temperature of 5° C. to obtain a composite coated scaffold. Q3. Immerse the composite coated stent in a 2.1 mg / mL dopamine hydrochloride solution, wherein the dopamine hydrochloride solution is prepared by dissolving dopamine hydrochloride in a Tris-HCl buffer solution at pH = 8.5, and oscillate at a temperature of 37° C., a speed of 70 rpm, and a time of 2.5 hours. Remove and rinse with ultrapure water three times, and dry at a temperature of 41° C. and a time of 25 hours to obtain a degradable bioscaffold material.

[0023] Example 3: This embodiment discloses a method for preparing a degradable biological scaffold material, comprising the following steps: (1) Using magnesium ingot, gallium ingot and MgO powder as raw materials, the scaffold material is obtained by hot extrusion and femtosecond laser engraving; (2) The surface of the scaffold material is covered with a polylactic acid-gelatin magnesium ion composite coating by electrospinning, and finally coated with a polydopamine emulsion to obtain a degradable biological scaffold material.

[0024] Among them, step (1) specifically includes the following process: S1. 97 g of magnesium ingot, 3.2 g of gallium ingot and 0.5 g of MgO powder were stirred and mixed at a stirring speed of 180 rpm for 30 min, and vacuum arc melting was performed. Vacuum was evacuated and argon was introduced as a protective gas. The melting temperature was 760° C. and the melting time was 60 min. The mixture was cooled in a water-cooled copper mold to obtain a magnesium alloy billet. S2. The magnesium alloy billet was heated to 390°C at a heating rate of 16°C / min and hot extruded at an extrusion ratio of 12:1 to obtain a rod with a diameter of 4.2 mm. Gradient holes were engraved on the rod by femtosecond laser at a wavelength of 1050 nm, a pulse energy of 2.2 mJ, and a scanning speed of 300 mm / s. The pore size gradient of the gradient holes was as follows: outer layer (pressure-bearing zone): pore size 100 μm, porosity 32%; transition layer: pore size 300 μm, porosity 50%; core layer (vascular zone): pore size 500 μm, porosity 70%, micro-grooves with a depth of 10 μm and a spacing of 50 μm, to obtain a stent material. Among them, step (2) specifically includes the following process: Q1. Place 410 mL of corn oil in a stirring container and stir. Simultaneously, add dropwise 100 mL of gelatin magnesium solution, which is prepared by adding gelatin to deionized water and stirring in a 55°C water bath to dissolve. Add MgCl2·6H2O solid and stir to dissolve to obtain a gelatin magnesium solution, wherein the amount ratio of gelatin, MgCl2·6H2O solid and deionized water is 12 g:0.1 mmol:100 mL; stir at 900 rpm and continue stirring for 10 minutes to obtain an emulsion; freeze the emulsion at a freezing temperature of -18°C for 3 hours, add 0.6 wt% glutaraldehyde solution for cross-linking reaction, and the cross-linking reaction time is 40 minutes to obtain magnesium ion gelatin microspheres; Q2. 35 g of magnesium ion gelatin microspheres were added to 1 L of a 7.5 wt % polylactic acid solution, wherein the polylactic acid solution was dissolved in hexafluoroisopropanol and stirred at 42° C. for 6-8 h at a speed of 150 rpm; the average relative molecular mass of the polylactic acid was 100 kDa; the ultrasonic treatment time was 40 min to obtain a spinning solution, which was loaded into a syringe of an electrospinning apparatus, and the scaffold material was electrospun at an electrospinning voltage of 18 kV, a receiving distance of 15.5 cm, a propulsion rate of 1.2 ml / h, and an electrospinning temperature of 7° C. to obtain a composite coated scaffold; Q3. Immerse the composite coated stent in a 2.2 mg / mL dopamine hydrochloride solution, wherein the dopamine hydrochloride solution is prepared by dissolving dopamine hydrochloride in a Tris-HCl buffer solution at pH = 8.5, and oscillate at a temperature of 37.5°C, a speed of 80 rpm, and a time of 3 hours. Remove and rinse with ultrapure water three times, and dry at a temperature of 42°C and a time of 26 hours to obtain a degradable bioscaffold material.

[0025] Comparative Example 1: Comparative Example 1 Compared with Example 3, in the preparation process of the degradable bioscaffold material in Comparative Example 1, no MgCl2·6H2O solid was added, and other conditions remained unchanged.

[0026] Comparative Example 2: Comparative Example 2 Compared with Example 3, in the preparation process of the degradable bioscaffold material in Comparative Example 2, no spinning solution was added, and other conditions remained unchanged.

[0027] Comparative Example 3: This comparative example discloses a method for preparing a degradable biological scaffold material, comprising the following steps: (1) Using magnesium ingot, gallium ingot and MgO powder as raw materials, the scaffold material is obtained by hot extrusion and femtosecond laser engraving; (2) The surface of the scaffold material is covered with a polylactic acid-gelatin magnesium ion composite coating by electrospinning, and finally coated with a polydopamine emulsion to obtain a degradable biological scaffold material.

[0028] Among them, step (1) specifically includes the following process: S1. 97 g of magnesium ingot, 3.2 g of gallium ingot and 0.5 g of MgO powder were stirred and mixed at a stirring speed of 180 rpm for 30 min, and vacuum arc melting was performed. Vacuum was evacuated and argon was introduced as a protective gas. The melting temperature was 760° C. and the melting time was 60 min. The mixture was cooled in a water-cooled copper mold to obtain a magnesium alloy billet. S2. The magnesium alloy billet was heated to 390°C at a heating rate of 16°C / min and hot extruded at an extrusion ratio of 12:1 to obtain a rod with a diameter of 4.2 mm. Gradient holes were engraved on the rod by femtosecond laser at a wavelength of 1050 nm, a pulse energy of 2.2 mJ, and a scanning speed of 300 mm / s. The pore size gradient of the gradient holes was as follows: outer layer (pressure-bearing zone): pore size 100 μm, porosity 32%; transition layer: pore size 300 μm, porosity 50%; core layer (vascular zone): pore size 500 μm, porosity 70%, micro-grooves with a depth of 10 μm and a spacing of 50 μm, to obtain a stent material. Among them, step (2) specifically includes the following process: Q1. Place 410 mL of corn oil in a stirring container and stir. Simultaneously, add dropwise 100 mL of gelatin magnesium solution, which is prepared by adding gelatin to deionized water and stirring in a 55°C water bath to dissolve. Add MgCl2·6H2O solid and stir to dissolve to obtain a gelatin magnesium solution, wherein the amount ratio of gelatin, MgCl2·6H2O solid and deionized water is 12 g:0.1 mmol:100 mL; stir at 900 rpm and continue stirring for 10 minutes to obtain an emulsion; freeze the emulsion at a freezing temperature of -18°C for 3 hours, add 0.6 wt% glutaraldehyde solution for cross-linking reaction, and the cross-linking reaction time is 40 minutes to obtain magnesium ion gelatin microspheres; Q2. 35 g of magnesium ion gelatin microspheres were added to 1 L of a 7.5 wt % polylactic acid solution, wherein the polylactic acid solution was dissolved in hexafluoroisopropanol and stirred at 42° C. for 6-8 h at a speed of 150 rpm; the average relative molecular mass of the polylactic acid was 100 kDa; the ultrasonic treatment time was 40 min to obtain a spinning solution, which was loaded into a syringe of an electrospinning apparatus, and the scaffold material was electrospun at an electrospinning voltage of 18 kV, a receiving distance of 15.5 cm, a propulsion rate of 1.2 ml / h, and an electrospinning temperature of 7° C. to obtain a composite coated scaffold; Q3. Immerse the composite coated stent in a 2.2 mg / mL dopamine hydrochloride solution, wherein the dopamine hydrochloride solution is prepared by dissolving dopamine hydrochloride in a Tris-HCl buffer solution at pH = 8.5, and oscillate at a temperature of 37.5°C, a speed of 80 rpm, and a time of 3 hours. Remove and rinse with ultrapure water three times, and dry at a temperature of 42°C and a time of 26 hours to obtain a degradable bioscaffold material.

[0029] Comparative Example 3 Compared with Example 3, in the preparation process of the degradable bioscaffold material in Comparative Example 3, no dopamine hydrochloride solution was added, and other conditions remained unchanged.

[0030] Experimental example: The properties of the degradable bioscaffold materials prepared in Examples 1-3 and Comparative Examples 1-3 were tested: 1. Mechanical properties test Compression performance testing was performed according to ISO 5833 "Compression Tests for Bone Scaffolds," processing the biodegradable bioscaffold materials prepared in Examples 1-3 and Comparative Examples 1-3 into cylinders with a sample size of Φ5 mm × 10 mm. The testing machine parameters were: a loading rate of 1 mm / min, and an endpoint of 30% strain or fracture. Coating adhesion was tested according to ASTM D4541 "Pull-off Adhesion Test." The biodegradable bioscaffold materials prepared in Examples 1-3 and Comparative Examples 1-3 were processed into specimens with a size of 10 × 10 × 3 mm³ (coating facing upward) and bonded to aluminum stakes with a diameter of 3 mm. The pull rate was 0.5 MPa / s, and the peel strength was recorded. The bending performance test was conducted according to ISO 7438. The biodegradable bioscaffold materials prepared in Examples 1-3 and Comparative Examples 1-3 were processed into rectangular strips: 30 mm in length, 5 mm in width, and 2 mm in thickness. Pretreatment was performed by immersing the strips in 37°C phosphate buffer for 26-28 hours at a loading rate of 1 mm / min. The test results are shown in Table 1. Table 1 Mechanical properties test results According to the test results in Table 1, the compressive strength, coating bonding strength, and flexural strength of the degradable bioscaffold material samples prepared in Examples 1-3 were improved compared with those in Comparative Examples 1-3. This shows that the addition of MgCl2·6H2O solid, spinning solution, and dopamine hydrochloride solution during the preparation of the degradable bioscaffold material helps to improve the mechanical properties of the scaffold.

[0031] 2. Degradation performance test According to ASTM G31 "Metal Immersion Corrosion" and ISO 10993-15 "Quantification of Degradation Products", the biodegradable scaffold material samples prepared in Examples 1-3 and Comparative Examples 1-3 were placed in a simulated body fluid (SBF, pH = 7.4) at 37°C. The samples were completely immersed and tested on the 28th day. The test results are shown in Table 2: Table 2 Degradation performance test results According to the test results in Table 2, compared with Comparative Examples 1-3, the biodegradable scaffold material samples prepared in Examples 1-3 have moderate degradation performance. 2+ When the release rate is 30-50 mg / L, it is the efficient range for promoting the expression of COL1 and OCN genes in osteocytes. At the same time, a balance can be achieved between promoting bone regeneration and safety. Therefore, the biological scaffold material prepared by the present invention has a suitable degradation rate.

[0032] 3. Cytotoxicity and osteogenic differentiation performance test According to ISO 10993-5 "Cytotoxicity Test," sample extracts were prepared by immersing the biodegradable bioscaffold material samples prepared in Examples 1-3 and Comparative Examples 1-3 in DMEM containing 10% fetal bovine serum at a ratio of 0.2 g / mL for 24 hours at 37°C. The extracts were then sterilized by filtration. A blank control was prepared using DMEM containing 10% fetal bovine serum. Cell culture and exposure: L929 mouse fibroblasts were selected as the cell line; the seeding density was 5×10 4 cells / well (96-well plate), cultured for 24 hours to adhere to the wall; exposure method was to discard the original culture medium, add 100 μL of extract solution, and incubate at 37°C, 5% CO2; CCK-8 method was used to detect cell viability: 10 μL of CCK-8 solution was added to each well, incubated, and the absorbance at 450 nm was measured using a microplate reader with a reference wavelength of 650 nm. The viability was calculated as (negative control OD - blank OD) / (sample OD - blank OD) × 100%. The test results are shown in Table 3. To test osteogenic differentiation, cells were first cultured for osteogenic induction using the following medium: α-MEM basal medium + 10% FBS + osteogenic induction agents (50 μg / mL ascorbic acid, 10 mM sodium β-glycerophosphate, and 100 nM dexamethasone). The induction period was 21 days, with the medium changed every 3 days. For alkaline phosphatase (ALP) activity, cells were washed with PBS and disrupted with lysis buffer (0.1% Triton X-100). The ALP substrate, pNPP, was added and incubated at 37°C in the dark for 30 minutes. ALP is a marker enzyme for osteogenic differentiation. It is secreted by osteoblasts and hydrolyzes pyrophosphate (a mineralization inhibitor) during the initial stages of bone mineralization, releasing phosphate ions. Phosphate combines with calcium ions to form hydroxyapatite, initiating bone matrix mineralization. Absorbance at 405 nm was measured with a microplate reader and quantified using a standard curve. The results are shown in Table 3. Table 3 Cytotoxicity and osteogenic differentiation performance test results According to the test results in Table 3, compared with Comparative Examples 1-3, the cell survival rate and ALP activity of the degradable bioscaffold material samples prepared in Examples 1-3 were improved. It can be seen that the addition of MgCl2·6H2O solid, spinning solution and dopamine hydrochloride solution in the preparation process of the degradable bioscaffold material helps to improve the safety of the bioscaffold and enhance the induction of osteogenic differentiation, which is conducive to bone repair.

[0033] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0034] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a degradable biological scaffold material, characterized in that: The steps include: (1) Using magnesium ingot, gallium ingot and MgO powder as raw materials, the scaffold material is obtained by hot extrusion and femtosecond laser engraving; (2) The surface of the scaffold material is covered with a polylactic acid-gelatin magnesium ion composite coating by electrospinning, and finally coated with a polydopamine emulsion to obtain a degradable biological scaffold material.

2. The method for preparing a degradable biological scaffold material according to claim 1, characterized in that: Step (1) specifically includes the following process: S1. Mixing magnesium ingot, gallium ingot and MgO powder, performing vacuum arc melting, and cooling to obtain magnesium alloy billet; S2. Heating the magnesium alloy billet and performing hot extrusion to obtain a rod; performing femtosecond laser engraving of gradient holes on the rod to obtain a stent material.

3. The method for preparing a degradable biological scaffold material according to claim 2, characterized in that: Preferably, the mass ratio of magnesium ingot, gallium ingot and MgO powder in S1 is (96-97): (2.9-3.2): (0.4-0.5).

4. The method for preparing a degradable biological scaffold material according to claim 2, characterized in that: Preferably, the heating temperature in S2 is 380-390° C., and the extrusion ratio during hot extrusion is 10-12:

1.

5. The method for preparing a degradable biological scaffold material according to claim 1, characterized in that: Step (2) specifically includes the following process: Q1. Place corn oil in a stirring container and stir while adding a gelatin magnesium solution dropwise and continue stirring to obtain an emulsion; freeze the emulsion and add a glutaraldehyde solution for cross-linking to obtain magnesium ion gelatin microspheres; Q2, adding magnesium ion gelatin microspheres to a polylactic acid solution, ultrasonically treating the solution to obtain a spinning solution, loading the spinning solution into a syringe of an electrospinning device, and electrospinning the stent material to obtain a composite coated stent; Q3. Immerse the composite coating stent in a dopamine hydrochloride solution, shake, take out, rinse, and dry to obtain a degradable biological stent material.

6. The method for preparing a degradable biological scaffold material according to claim 5, characterized in that: Preferably, the volume ratio of corn oil and gelatin magnesium solution in Q1 is (4-4.1):1; the gelatin magnesium solution is prepared by adding gelatin to deionized water, stirring and dissolving in a water bath at 50-55°C, adding MgCl2·6H2O solid, and stirring and dissolving to obtain the gelatin magnesium solution, wherein the amount ratio of gelatin, MgCl2·6H2O solid and deionized water is (10-12) g:0.1 mmol:100 mL; and the concentration of the glutaraldehyde solution is 0.5-0.6 wt%.

7. The method for preparing a degradable biological scaffold material according to claim 5, characterized in that: The mass ratio of magnesium ion gelatin microspheres to polylactic acid solution in Q2 is (3-3.5):100; the polylactic acid solution is obtained by dissolving polylactic acid in hexafluoroisopropanol and stirring, wherein the concentration of the polylactic acid solution is 7-7.5wt%.

8. The method for preparing a degradable biological scaffold material according to claim 1, characterized in that: The dopamine hydrochloride solution in Q3 is prepared by dissolving dopamine hydrochloride in Tris-HCl buffer at pH=8.

5. The concentration of the dopamine hydrochloride solution is 2-2.2 mg / mL.

9. A degradable biological scaffold material, characterized in that: The preparation method is as described in any one of claims 1 to 8.

10. Use of the degradable biological scaffold material according to claim 9 in bone tissue repair.

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