A semi-customized layered porous magnesium-based scaffold and its preparation method

Abstract

The present invention discloses a semi-customized layered porous magnesium-based scaffold and its preparation method. The scaffold comprises a first cylindrical porous magnesium scaffold, a second annular porous magnesium scaffold, and a third annular porous magnesium scaffold, which are nested from the inside out in descending order of height. The upper and lower surfaces of the first cylindrical porous magnesium scaffold are respectively provided with a first circular porous magnesium gasket having an inner diameter equal to that of the second annular porous magnesium scaffold; the upper and lower surfaces of the second annular porous magnesium scaffold are respectively provided with a second circular porous magnesium gasket having an inner diameter equal to that of the third annular porous magnesium scaffold. The semi-customized layered porous magnesium-based scaffold of the present invention achieves functional stratification according to the different stages of bone repair, and can also be customized for drug loading according to the patient's actual condition, with the customized size and hierarchical partitioning adjusted.

Description

Technical Field

[0001] The present invention relates to a bone repair biomaterial scaffold and a preparation method thereof, and in particular to a semi-customized layered porous magnesium-based scaffold and a preparation method thereof. Background Art

[0002] Once bone tissue is damaged, it is difficult for it to repair itself. Although many technologies have been applied to the treatment of bone defects in clinical practice, each treatment has its shortcomings. The research and development of bone tissue engineering has brought new ideas for the repair of bone defects.

[0003] Existing magnesium alloy bone repair scaffolds have excellent mechanical properties, with an elastic modulus close to that of human bone. They also exhibit good biocompatibility and are biodegradable in the human environment. The magnesium formed by degradation is absorbed by the body and promotes bone tissue recovery. However, the degradation rate of magnesium alloys is too high to match the bone tissue healing cycle. Furthermore, each patient's condition varies, and complications such as inflammation at the surgical site may occur, necessitating appropriate medication to aid tissue repair.

[0004] In recent years, various approaches have been explored to improve the degradation and functionalization of magnesium alloys, including surface treatment, heat treatment, and alloying. Patent CN109680319A proposes a method for preparing a corrosion-resistant, self-repairing coating on a magnesium alloy surface based on calcium salts. This method addresses the existing issues of magnesium alloy surface coatings being susceptible to failure and poor self-repair under corrosive conditions. However, the effects of some of these elements on the human body remain unclear.

[0005] In addition, patent CN115627512A prepares a composite coating on the surface of a magnesium alloy. The coating consists of a bottom layer with a porous structure and a functional surface layer, which has a certain antibacterial effect. However, the magnesium alloy has a single functionalization and its mechanical properties are unclear, which cannot meet the multifunctional requirements in the actual use of biological scaffolds.

[0006] Bone scaffold materials must possess excellent biocompatibility, a degradation rate compatible with bone tissue regeneration, and mechanical properties. Damaged tissue has different needs at different stages of the healing cycle. Initially, it is prone to inflammation, while in the middle and later stages, the implant needs to provide appropriate mechanical support and repair-promoting properties. Furthermore, the extent of damaged tissue varies from patient to patient, necessitating the development of a semi-customized scaffold that combines anti-infection properties with excellent biocompatibility and mechanical properties. Summary of the Invention

[0007] Purpose of the invention: The purpose of the present invention is to provide a semi-customized hierarchical porous magnesium-based scaffold that has both anti-infection effects and excellent biocompatibility and mechanical properties;

[0008] The second object of the present invention is to provide a method for preparing the above-mentioned semi-customized hierarchical porous magnesium-based scaffold.

[0009] Technical solution: The semi-customized layered porous magnesium-based bracket described in the present invention includes a first cylindrical porous magnesium bracket, a second annular porous magnesium bracket, and a third annular porous magnesium bracket, which are nested from the inside to the outside and decrease in height successively; the upper and lower surfaces of the first cylindrical porous magnesium bracket are respectively provided with a first circular porous magnesium gasket with an inner diameter equal to that of the second annular porous magnesium bracket; the upper and lower surfaces of the second annular porous magnesium bracket are respectively provided with a second circular porous magnesium gasket with an inner diameter equal to that of the third annular porous magnesium bracket.

[0010] At least one of the first cylindrical porous magnesium stent, the first circular porous magnesium gasket, the second annular porous magnesium stent, or the third annular porous magnesium stent is provided with a corrosion-resistant layer, a self-healing layer, or an antibacterial layer. The corrosion-resistant layer has a thickness of 3.5 to 4.1 μm; the self-healing layer has a thickness of 10 to 17 μm; and the antibacterial layer has a thickness of 0.8 to 5 mm. The pores of the porous magnesium stent are filled with drugs for customized drug delivery.

[0011] The composition of the magnesium alloy includes 0wt% to 1.8wt% of Mn or 0wt% to 0.3wt% of Ca, 1wt% to 6wt% of Zn, and the balance is Mg; the porous magnesium has a through-pore structure with a pore size range of 200 to 900 μm, a porosity of 50% to 80%, and a compressive yield strength of 1 to 30 MPa.

[0012] The above-mentioned method for preparing a semi-customized layered porous magnesium-based bracket is to use a template replication method to prepare a first cylindrical porous magnesium bracket and a first circular porous magnesium gasket using a first cylindrical mold; to prepare a second circular porous magnesium gasket using a second cylindrical mold; to prepare a second annular porous magnesium bracket and a third annular porous magnesium bracket using a second annular mold and a third annular mold respectively; the inner diameter of the second annular mold is equal to the diameter of the first cylindrical mold, the outer diameter of the second annular mold is equal to the diameter of the second cylindrical mold, and the inner diameter of the third annular mold is equal to the outer diameter of the second annular mold; the inner diameter of the second annular porous magnesium bracket is equal to the diameter of the first cylindrical porous magnesium bracket, and is also equal to the diameter of the first circular porous magnesium gasket; the inner diameter of the third annular porous magnesium bracket is equal to the outer diameter of the second annular porous magnesium bracket, and is also equal to the diameter of the second circular porous magnesium gasket.

[0013] Among them, the height of the first circular porous magnesium gasket is equal to half of the height difference between the second annular porous magnesium bracket and the first cylindrical porous magnesium bracket; the height of the second circular porous magnesium gasket is equal to half of the height difference between the third annular porous magnesium bracket.

[0014] Among them, the template replication method includes: screening filling particles with a particle size range of 200-900μm and placing them in a first cylindrical mold, a second cylindrical mold, a second annular mold and a third annular mold to make a filling template, infiltrating the magnesium alloy melt into the gaps of the filling template in a negative pressure infiltration device, demolding and filtering out the filling template after natural cooling, and then it can be obtained by mechanical processing.

[0015] Among them, the first cylindrical porous magnesium bracket is inserted into the second annular porous magnesium bracket, and then the whole is inserted into the third annular porous magnesium bracket. Two first circular porous magnesium gaskets are placed on the upper and lower surfaces of the first cylindrical porous magnesium bracket respectively, and two second circular porous magnesium gaskets are placed on the upper and lower surfaces of the second annular porous magnesium bracket respectively, and finally assembled into a semi-customized layered porous magnesium-based bracket.

[0016] Among them, the corrosion-resistant layer is prepared on the first cylindrical porous magnesium support, the second annular porous magnesium support or the third annular porous magnesium support, and the method is: immersing the first cylindrical porous magnesium support, the second annular porous magnesium support or the third annular porous magnesium support in 40-48% HF fluoride solution, performing hydrothermal treatment at a temperature of 37-85°C for 40-42 hours, and drying to obtain the corrosion-resistant layer.

[0017] Among them, a self-healing layer is prepared on the first cylindrical porous magnesium support, the second annular porous magnesium support or the third annular porous magnesium support and / or the surface of the first circular porous magnesium gasket or the second circular porous magnesium gasket, and the method is: placing the first cylindrical porous magnesium support, the second annular porous magnesium support or the third annular porous magnesium support and / or the first circular porous magnesium gasket or the second circular porous magnesium gasket in a self-healing liquid flowing at room temperature, the self-healing liquid is the supernatant after Ca(NO3)2 and NH4H2PO4 are fully dissolved in a mixture; after chemical conversion treatment for 1 to 3 hours, drying is carried out to obtain the self-healing layer.

[0018] The antibacterial layer is prepared on the first cylindrical porous magnesium support, the second annular porous magnesium support or the third annular porous magnesium support and / or on the surface of the first circular porous magnesium gasket or the second circular porous magnesium gasket by mixing sodium methacrylamide alginate and a photoinitiator with a supersaturated zinc sulfate solution in a mass volume ratio of 50 to 150:1, and stirring the mixture thoroughly to form a gel precursor fluid; The porous magnesium gasket or the second circular porous magnesium gasket and the gel precursor liquid are respectively placed in a closed mold, the interior of the closed device is pressurized to make the gel precursor liquid fully penetrate the porous magnesium pores and the surface, and then the gel precursor liquid is solidified into a gel to form an antibacterial layer; preferably, the mold is a transparent closed mold; ultraviolet light is used to solidify the precursor liquid into a gel to form an antibacterial layer; wherein; a 365-450nm ultraviolet lamp is used to irradiate for 30-120s to pressurize the interior of the closed device to 0.5-2.0MPa and maintain it for 5-30min.

[0019] The present invention preferably forms a corrosion-resistant layer on the surface of the first cylindrical porous magnesium stent; a self-healing layer and drug-loading layer on the surface of the first circular porous magnesium gasket and the second annular porous magnesium stent; and an antibacterial layer on the surface of the second circular porous magnesium gasket and the third annular porous magnesium stent. The outermost antibacterial layer is used to reduce inflammation and infection because wound infection can occur during the initial implantation process. A hydrogel containing antibacterial ions is coated on the stent surface; the inner corrosion-resistant layer and self-healing layer reduce the degradation rate.

[0020] The corrosion-resistant and self-healing layers of the present invention are both micron-scale coatings produced through chemical reactions and deposited on the exposed surfaces of the porous stent, including the stent's exterior and pore surfaces. Drug delivery is achieved by filling the stent's porous pores with powdered or liquid drugs. The drug can be selected based on actual needs, and the drug-loading layers can be arranged in different layers as needed.

[0021] Beneficial effects: Compared with the prior art, the present invention has achieved the following significant effects: (1) It can realize independent treatment of each layer of the stent to obtain different functionalities, and the surface treatment of each layer of the stent does not affect each other; the stent matrix material adopts the excellent biodegradable material porous magnesium alloy, and the stent is provided with an antibacterial layer, so it has both anti-infection effect and excellent biocompatibility and mechanical properties. (2) During the assembly of the stent, specific drugs can be selected according to the patient's condition to be filled into the pores of the second annular porous magnesium stent and the first circular porous magnesium gasket, which can achieve customized drug loading. (3) The first antibacterial layer of the stent, through gel-loaded antibacterial ions, can achieve the anti-infection effect of the stent in the early stage of implantation; the second self-repairing drug-loading layer of the stent, can select drugs according to the patient's condition to be filled into the stent pores to achieve the effect of drug treatment. At the same time, the self-repairing coating can not only slow down the degradation rate of the stent, but also has good biocompatibility and can promote cell proliferation and differentiation; the third corrosion-resistant layer of the stent further controls the degradation rate of the stent and prolongs the degradation cycle to match the healing cycle of bone tissue. (4) According to the differences in the patient's age and bone repair ability, stent components with different magnesium alloy compositions can be selected to assemble to obtain a porous magnesium stent, so as to match the patient's healing cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the overall structure of the semi-customized hierarchical porous magnesium-based scaffold of the present invention;

[0023] Figure 2 A top view and a cross-sectional view of the semi-customized hierarchical porous magnesium-based scaffold of the present invention;

[0024] Figure 3 This is a flow chart of the preparation method of the semi-customized hierarchical porous magnesium-based scaffold of the present invention. DETAILED DESCRIPTION

[0025] The present invention is described in further detail below.

[0026] Example 1

[0027] like Figure 1 、 2As shown, the present invention provides a semi-customized layered porous magnesium-based support, comprising a first cylindrical porous magnesium support 1, a second annular porous magnesium support 2 nested outside the first cylindrical porous magnesium support 1, and a third annular porous magnesium support 3 nested outside the second annular porous magnesium support 2. The heights of the first cylindrical porous magnesium support 1, the second annular porous magnesium support 2, and the third annular porous magnesium support 3 increase in sequence. First circular porous magnesium gaskets 4, each with an inner diameter equal to that of the second annular porous magnesium support 2, are provided on the upper and lower surfaces of the first cylindrical porous magnesium support 1. Second circular porous magnesium gaskets 5, each with an inner diameter equal to that of the third annular porous magnesium support 3, are provided on the upper and lower surfaces of the second annular porous magnesium support 2. In this embodiment, the height of the first circular porous magnesium gasket 4 is equal to half the height difference between the second annular porous magnesium support 2 and the first cylindrical porous magnesium support 1; the height of the second circular porous magnesium gasket 5 is equal to half the height difference between the third annular porous magnesium support 3. The inner diameter of the second annular porous magnesium support is equal to the diameter of the first cylindrical porous magnesium support and the diameter of the first circular porous magnesium gasket; the inner diameter of the third annular porous magnesium support is equal to the outer diameter of the second annular porous magnesium support and the diameter of the second circular porous magnesium gasket.

[0028] In this embodiment, the surface of the first cylindrical porous magnesium bracket 1 is provided with a corrosion-resistant layer; the surfaces of the first circular porous magnesium gasket 4 and the second annular porous magnesium bracket 2 are provided with a self-repairing layer. Before implantation, liquid or powdered drugs can be selected according to the patient's condition to fill the pores of the first circular porous magnesium gasket 4 and the second annular porous magnesium bracket 2 to achieve customized drug loading; the surfaces of the second circular porous magnesium gasket 5 and the third annular porous magnesium bracket 3 are provided with an antibacterial layer.

[0029] The semi-customized layered porous magnesium-based scaffold preparation method in this embodiment has the following specific steps:

[0030] Step 1: Filler particles with a particle size range of 300-450 μm were screened and placed in a first cylindrical mold, a second cylindrical mold, a second annular mold, and a third annular mold, respectively, and hot-pressed and sintered to form a filling template. An Mg0.3Ca magnesium alloy ingot was melted in a negative pressure infiltration device and infiltrated into the voids of the filling template. After natural cooling, the molds were removed and the filling template was filtered out. Mechanical processing was performed to produce a first cylindrical porous magnesium scaffold 1 (Φ4×4 mm), a second annular porous magnesium scaffold 2 (Φ8×4×8 mm), a third annular porous magnesium scaffold 3 (Φ12×8×12 mm), a first circular porous magnesium gasket 4 (Φ2×2 mm), and a second circular porous magnesium gasket 5 (Φ2×2 mm). The resulting porous magnesium had a through-hole structure with a pore size range of 250-450 μm, a porosity of 55%-70%, and a compressive yield strength of 5-20 MPa.

[0031] Step 2: The first cylindrical porous magnesium support 1 obtained in step 1 is immersed in 40% HF fluoride solution, subjected to hydrothermal treatment at 80°C for 40 hours, and dried to form a corrosion-resistant layer on the surface of the first cylindrical porous magnesium support 1 with a thickness of 3.5 μm.

[0032] Step 3: Place the first circular porous magnesium gasket 4 and the second annular porous magnesium support 2 obtained in Step 1 in a room-temperature flowing self-healing solution composed of a fully dissolved mixture of Ca(NO3)2 and NH4H2PO4 in a mass ratio of 5:2. After chemical conversion treatment for 1 hour and drying, a 10μm-thick self-healing layer is formed on the surfaces of the first circular porous magnesium gasket 4 and the second annular porous magnesium support 2.

[0033] Step 4: Mix the methacrylamide sodium alginate and photoinitiator with a supersaturated zinc sulfate solution at a mass-to-volume ratio of 50:1. Place the mixture in a blender and stir thoroughly to form a pregel solution;

[0034] The second circular porous magnesium gasket 5 and the third annular porous magnesium bracket 3 obtained in step 1 are placed in a transparent sealed mold respectively with the gel precursor liquid, and the interior of the sealed device is pressurized to 2 MPa and maintained for 30 minutes to allow the gel precursor liquid to fully penetrate the porous magnesium pores and surface under the action of pressure. Use a 450nm ultraviolet lamp to irradiate for 1 minute to solidify the precursor liquid into a gel, and prepare an antibacterial layer on the surface of the second circular porous magnesium gasket 5 and the third annular porous magnesium bracket 3, with a thickness of 1 mm.

[0035] Step 5: Select liquid or powder drugs according to the patient's condition and fill them into the pores of the second annular porous magnesium bracket 2 obtained in step 2 and the first circular porous magnesium gasket 4 obtained in step 3. Insert the first cylindrical porous magnesium bracket 1 obtained in step 2 into the second annular porous magnesium bracket 2, and then insert the whole into the third annular porous magnesium bracket 3 obtained in step 4. Place two pieces of the first circular porous magnesium gaskets 4 on the upper and lower surfaces of the first cylindrical porous magnesium bracket 1, and place two pieces of the second circular porous magnesium gaskets 5 obtained in step 4 on the upper and lower surfaces of the second annular porous magnesium bracket 2. Finally, assemble them into a semi-customized layered porous magnesium-based bracket.

[0036] Example 2

[0037] The specific steps of the semi-customized layered porous magnesium-based stent preparation method of this embodiment are as follows:

[0038] Step 1: Filler particles with a particle size range of 450-600 μm were screened and placed in a first cylindrical mold, a second cylindrical mold, a second annular mold, and a third annular mold, respectively, and hot-pressed and sintered to form a filling template. An Mg6Zn0.3Ca magnesium alloy ingot was melted in a negative pressure infiltration device and infiltrated into the voids of the filling template. After natural cooling, the molds were removed and the filling template was filtered out. Mechanical processing was performed to produce a first cylindrical porous magnesium scaffold (1) with dimensions of 4 × 4 mm, a second annular porous magnesium scaffold (2) with dimensions of 10 × 4 × 8 mm, a third annular porous magnesium scaffold (3) with dimensions of 14 × 10 × 10 mm, a first circular porous magnesium gasket (4) with dimensions of 4 × 2 mm, and a second circular porous magnesium gasket (5) with dimensions of 10 × 1 mm. The resulting porous magnesium had a through-hole structure with a pore size range of 400-60 μm, a porosity of 60%-75%, and a compressive yield strength of 3-18 MPa.

[0039] Step 2: The first cylindrical porous magnesium support 1 obtained in step 1 is immersed in 45% HF fluoride solution, subjected to hydrothermal treatment at 80°C for 42 hours, and dried to form a corrosion-resistant layer on the surface of the first cylindrical porous magnesium support 1 with a thickness of 4.1 μm.

[0040] Step 3: Place the first circular porous magnesium gasket 4 and the second annular porous magnesium support 2 obtained in Step 1 in a room-temperature flowing self-healing solution composed of a fully dissolved mixture of Ca(NO3)2 and NH4H2PO4 in a mass ratio of 5:2. After a 3-hour chemical conversion treatment and drying, a 17μm-thick self-healing layer is formed on the surfaces of the first circular porous magnesium gasket 4 and the second annular porous magnesium support 2.

[0041] Step 4: Mix the methacrylamide sodium alginate and the photoinitiator with a supersaturated zinc sulfate solution at a mass-to-volume ratio of 100:1. Place the mixture in a blender and stir thoroughly to form a pregel solution;

[0042] The second circular porous magnesium gasket 5 and the third annular porous magnesium bracket 3 obtained in step 1 are placed in a transparent sealed mold respectively with the gel precursor liquid, and the interior of the sealed device is pressurized to 2 MPa and maintained for 30 minutes to allow the gel precursor liquid to fully penetrate the porous magnesium pores and surface under the action of pressure. Use a 450nm ultraviolet lamp to irradiate for 1 minute to solidify the precursor liquid into a gel, and prepare an antibacterial layer on the surface of the second circular porous magnesium gasket 5 and the third annular porous magnesium bracket 3, with a thickness of 0.8 mm.

[0043] Step 5: Select liquid or powder drugs according to the patient's condition and fill them into the pores of the second annular porous magnesium bracket 2 obtained in step 2 and the first circular porous magnesium gasket 4 obtained in step 3. Insert the first cylindrical porous magnesium bracket 1 obtained in step 2 into the second annular porous magnesium bracket 2, and then insert the whole into the third annular porous magnesium bracket 3 obtained in step 4. Place two pieces of the first circular porous magnesium gaskets 4 on the upper and lower surfaces of the first cylindrical porous magnesium bracket 1, and place two pieces of the second circular porous magnesium gaskets 5 obtained in step 4 on the upper and lower surfaces of the second annular porous magnesium bracket 2. Finally, assemble them into a semi-customized layered porous magnesium-based bracket.

[0044] Example 3

[0045] The semi-customized layered porous magnesium-based scaffold preparation method in this embodiment has the following specific steps:

[0046] Step 1: Filler particles with a particle size range of 300-800 μm were screened and placed in a first cylindrical mold, a second cylindrical mold, a second annular mold, and a third annular mold, respectively, and hot-pressed and sintered to form a filling template. An Mg3Zn1.5Mn0.3Ca magnesium alloy ingot was melted in a negative pressure infiltration device and infiltrated into the voids of the filling template. After natural cooling, the molds were removed and the filling template was filtered out. Mechanical processing was performed to produce a first cylindrical porous magnesium scaffold (1) with dimensions of 4 × 4 mm, a second annular porous magnesium scaffold (2) with dimensions of 10 × 4 × 8 mm, a third annular porous magnesium scaffold (3) with dimensions of 14 × 10 × 10 mm, a first circular porous magnesium gasket (4) with dimensions of 4 × 2 mm, and a second circular porous magnesium gasket (5) with dimensions of 10 × 1 mm. The resulting porous magnesium had a through-hole structure with a pore size range of 260-850 μm, a porosity of 50%-80%, and a compressive yield strength of 1-25 MPa.

[0047] Step 2: The first cylindrical porous magnesium support 1 obtained in step 1 is immersed in 48% HF fluoride solution at 80°C for 40 hours for hydrothermal treatment, and then dried to form a corrosion-resistant layer on the surface of the first cylindrical porous magnesium support 1 with a thickness of 3.8 μm.

[0048] Step 3: Place the first circular porous magnesium gasket 4 and the second annular porous magnesium support 2 obtained in Step 1 in a room-temperature flowing self-healing solution composed of a fully dissolved mixture of Ca(NO3)2 and NH4H2PO4 in a mass ratio of 5:2. After chemical conversion treatment for 2 hours and drying, a self-healing layer with a thickness of 14 μm is formed on the surfaces of the first circular porous magnesium gasket 4 and the second annular porous magnesium support 2.

[0049] Step 4: Mix the methacrylamide sodium alginate and photoinitiator with a supersaturated zinc sulfate solution at a mass-to-volume ratio of 150:1. Place the mixture in a blender and stir thoroughly to form a pregel solution;

[0050] The second circular porous magnesium gasket 5 and the third annular porous magnesium bracket 3 obtained in step 1 are placed in a transparent sealed mold respectively with the gel precursor liquid, and the interior of the sealed device is pressurized to 2 MPa and maintained for 30 minutes to allow the gel precursor liquid to fully penetrate the porous magnesium pores and surface under the action of pressure. Use a 450nm ultraviolet lamp to irradiate for 1 minute to solidify the precursor liquid into a gel, and prepare an antibacterial layer on the surface of the second circular porous magnesium gasket 5 and the third annular porous magnesium bracket 3, with a thickness of 5 mm.

[0051] Step 5: Select liquid or powder drugs according to the patient's condition and fill them into the pores of the second annular porous magnesium bracket 2 obtained in step 2 and the first circular porous magnesium gasket 4 obtained in step 3. Insert the first cylindrical porous magnesium bracket 1 obtained in step 2 into the second annular porous magnesium bracket 2, and then insert the whole into the center of the third annular porous magnesium bracket 3 obtained in step 4. Place two pieces of the first circular porous magnesium gaskets 4 on the upper and lower surfaces of the first cylindrical porous magnesium bracket 1, and place two pieces of the second circular porous magnesium gaskets 5 obtained in step 4 on the upper and lower surfaces of the second annular porous magnesium bracket 2. Finally, assemble them into a semi-customized layered porous magnesium-based bracket.

Claims

1. A semi-customized layered porous magnesium-based scaffold, characterized in that: The invention comprises a first cylindrical porous magnesium support (1), a second annular porous magnesium support (2), and a third annular porous magnesium support (3) which are nested from the inside out, wherein the heights of the first cylindrical porous magnesium support (1), the second annular porous magnesium support (2), and the third annular porous magnesium support (3) are successively increased; the upper and lower surfaces of the first cylindrical porous magnesium support (1) are respectively provided with a first circular porous magnesium gasket (4) having an inner diameter equal to that of the second annular porous magnesium support (2); the upper and lower surfaces of the second annular porous magnesium support (2) are respectively provided with a second circular porous magnesium gasket (5) having an inner diameter equal to that of the third annular porous magnesium support (3); The surface of the first cylindrical porous magnesium stent (1) is provided with a corrosion-resistant layer; the surfaces of the first circular porous magnesium gasket (4) and the second annular porous magnesium stent (2) are provided with a self-repairing layer, and before implantation, liquid or powdered medicine can be selected according to the patient's condition and filled into the pores of the first circular porous magnesium gasket (4) and the second annular porous magnesium stent (2) to achieve customized drug loading; the surfaces of the second circular porous magnesium gasket (5) and the third annular porous magnesium stent (3) are provided with an antibacterial layer; The first cylindrical porous magnesium support (1) is inserted into the second annular porous magnesium support (2), and the whole is then inserted into the third annular porous magnesium support (3). Two first circular porous magnesium gaskets (4) are respectively placed on the upper and lower surfaces of the first cylindrical porous magnesium support (1), and two second circular porous magnesium gaskets (5) are respectively placed on the upper and lower surfaces of the second annular porous magnesium support (2), and finally a semi-customized layered porous magnesium-based support is assembled.

2. The semi-customized hierarchical porous magnesium-based bracket according to claim 1, characterized in that: The porous magnesium has a through-hole structure, a pore size range of 200-900 μm, a porosity of 50%-80%, and a compressive yield strength of 1-30 MPa.

3. A method for preparing the semi-customized hierarchical porous magnesium-based scaffold according to claim 1, characterized in that: By means of a template replication method, a first cylindrical porous magnesium support (1) and a first circular porous magnesium gasket (4) are prepared using a first cylindrical mold; a second circular porous magnesium gasket (5) is prepared using a second cylindrical mold; a second annular porous magnesium support (2) and a third annular porous magnesium support (3) are prepared using a second annular mold and a third annular mold, respectively; the inner diameter of the second annular mold is equal to the diameter of the first cylindrical mold, the outer diameter of the second annular mold is equal to the diameter of the second cylindrical mold, and the inner diameter of the third annular mold is equal to the outer diameter of the second annular mold.

4. The method for preparing a semi-customized hierarchical porous magnesium-based scaffold according to claim 3, characterized in that: The template replication method includes: screening filling particles with a particle size range of 200-900 μm and placing them in a first cylindrical mold, a second cylindrical mold, a second annular mold and a third annular mold to form a filling template, infiltrating a magnesium alloy melt into the gaps of the filling template in a negative pressure infiltration device, demolding after natural cooling and filtering out the filling template, and then the product can be obtained by mechanical processing.

5. The method for preparing a semi-customized hierarchical porous magnesium-based scaffold according to claim 3, characterized in that: A corrosion-resistant layer is prepared on the surface of a first cylindrical porous magnesium support (1), wherein the method comprises: immersing the first cylindrical porous magnesium support (1) in a 40-48% HF fluoride solution, performing a hydrothermal treatment at a temperature of 37-85° C. for 40-42 hours, and drying the resultant layer.

6. The method for preparing a semi-customized hierarchical porous magnesium-based scaffold according to claim 3, characterized in that: A self-repairing layer is prepared on the surface of a second annular porous magnesium support (2) and a first circular porous magnesium gasket (4), wherein the second annular porous magnesium support (2) and the first circular porous magnesium gasket (4) are placed in a self-repairing liquid flowing at room temperature, wherein the self-repairing liquid is a supernatant obtained by fully dissolving a mixture of Ca(NO3)2 and NH4H2PO4; and after chemical conversion treatment, the self-repairing layer is dried to obtain the self-repairing layer.

7. The method for preparing a semi-customized hierarchical porous magnesium-based scaffold according to claim 3, characterized in that: An antibacterial layer is prepared on the third annular porous magnesium support (3) and on the surface of the second circular porous magnesium gasket (5), by mixing methacrylamide sodium alginate with a photoinitiator and a supersaturated zinc sulfate solution, and stirring the mixture thoroughly to form a gel precursor liquid; placing the third annular porous magnesium support (3) and the second circular porous magnesium gasket (5) and the gel precursor liquid in a sealed mold respectively, applying pressure to the interior of the sealed device so that the gel precursor liquid fully penetrates the porous magnesium pores and the surface, and then solidifying the gel precursor liquid into a gel to form the antibacterial layer.

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