Magnesium alloy-hydroxyapatite composite bone prosthesis and preparation method thereof

Abstract

The invention provides a magnesium alloy-hydroxyapatite composite bone prosthesis and a preparation method thereof.The preparation method of the magnesium alloy-hydroxyapatite composite bone prosthesis comprises the following steps that a target bone is scanned through CT, and a three-dimensional model containing an appearance structure and an internal structure is obtained; simplifying the appearance structure of the bone prosthesis, simulating an internal porous structure of the bone prosthesis, and designing a three-dimensional structure of the bone prosthesis; preparing hydroxyapatite printing slurry; printing a hydroxyapatite bracket by using a three-dimensional photocuring technology; carrying out cleaning, degreasing and high-temperature sintering on the hydroxyapatite scaffold; injecting molten magnesium alloy into the hydroxyapatite stent by using a pressureless permeation technology; and removing redundant materials by adopting a cutting tool, and grinding and polishing to obtain the magnesium alloy-hydroxyapatite composite bone prosthesis. The prepared magnesium alloy-hydroxyapatite composite auditory ossicle prosthesis has the advantages of being stable in positioning, not prone to shifting and disengaging, high in sound conduction efficiency, controllable in cost and capable of achieving personalized customization.

Description

Technical Field

[0001] This invention relates to bone prosthesis fabrication technology, and more particularly to a magnesium alloy-hydroxyapatite composite bone prosthesis and its fabrication method. Background Technology

[0002] The ossicular chain, composed of ossicles including the malleus, incus, and stapes, is a crucial sound-conducting structure in the middle ear. When the ear is diseased, the ossicles are easily affected, leading to ossicular chain breakage or loss, resulting in conductive hearing loss. The incidence of chronic suppurative otitis media in my country is 2%-4%, with clinical manifestations including ear discharge, hearing loss, tinnitus, and vertigo. Ossicular chain problems account for approximately 60% of chronic middle ear diseases. Ossicular chain reconstruction is the only treatment for broken or missing ossicles. Surgery restores the continuity and integrity of the ossicular chain, reconstructing a normal sound conduction pathway, thereby improving hearing and auditory function. Ossicular chain reconstruction includes autologous bone reconstruction and artificial ossicle reconstruction. The use of artificial ossicles is increasingly common, especially for patients with chronic otitis media, cholesteatoma, and ossicular chain malformations. For otolaryngologists, finding a biocompatible, biostable, effective, simple, readily available, fast, inexpensive, and complication-free material is a pressing issue.

[0003] The ossicles are the three smallest bones in the human body, including the malleus, incus, and stapes, located in the upper part of the tympanic cavity. They are connected by joints to form the ossicular chain, linking the tympanic membrane and the oval window. They are the main sound-conducting structures in the middle ear. Ossicles can be missing or broken due to disease. When autologous bone cannot repair them, artificial ossicles are needed. Current materials for artificial ossicles include polyethylene, Teflon, polymer materials, bioceramics, and titanium. Composite prostheses made of multiple materials are also available, each with its own advantages and disadvantages. Polyethylene, Teflon, and polymer materials have relatively high excretion rates. Ceramic has the advantage of being close to the inorganic components of human bone, resulting in good tissue compatibility. Its disadvantage is its brittleness and difficulty in shaping. Pure titanium has advantages such as good biocompatibility, rigidity, stability, high precision, and good sound conduction performance. However, its disadvantage is its hardness, making it prone to perforating the tympanic membrane and dislodging. Furthermore, the prosthesis may connect with the bone, causing fixation of the stapes footplate and leading to surgical failure. Titanium alloy ossicles are widely used in clinical practice due to their advantages such as resistance to deformation, good sound transmission, light weight, good corrosion resistance and tissue compatibility, and low rejection rate. Titanium alloy ossicles are mainly divided into:

[0004] Totally implantable ossicular prosthesis (TORP) and partially implantable ossicular prosthesis (PORP). TORP is suitable for partial ossicular replacement, with the prosthesis attached to the stapes head. TORP is used for total ossicular replacement, with the prosthesis directly attached to the stapes footplate. Titanium alloys are widely used in ossicular chain reconstruction surgery, greatly improving the postoperative recovery rate of patients, but there are still shortcomings.

[0005] Firstly, titanium alloy ossicles still pose risks of dislodgement, displacement, and unstable fixation. Furthermore, during surgery, adhesion between the titanium alloy prosthesis and the stapes footplate was observed, leading to footplate fixation, impacting surgical outcomes, and resulting in surgical failure. Secondly, while titanium alloy ossicles are designed with different lengths, their models are relatively fixed, failing to meet individual patient needs. Titanium alloy ossicles are not conducive to human tissue growth and differ from natural ossicles in sound conduction, potentially causing resonance in certain frequency bands and resulting in discomfort, especially in special environments such as airplanes or high-frequency processing. Moreover, the linear solid structure of titanium alloy differs from the cortical and cancellous bone fusion of natural human ossicles, lacking sufficient shock resistance and cushioning capacity, affecting sound conduction. Additionally, certain elements in titanium alloys may cause infection problems, further increasing the risks associated with its use. Finally, the high price of titanium alloy artificial ossicles makes them unaffordable for many patients with limited financial means. Therefore, there is an urgent need for a new type of ossicle prosthesis to solve the problems of unstable fixation, easy infection, poor sound conduction, and inability to be customized for patients. This would allow for personalized customization of ossicle prostheses with better overall performance and lower prices, thereby improving patients' hearing recovery ability and applicability in various scenarios. Summary of the Invention

[0006] The purpose of this invention is to address the problems of current titanium alloy bone prostheses (especially titanium alloy ossicular prostheses), such as easy displacement, easy dislodgement, poor sound conduction, high cost, and inability to be customized. This invention proposes a method for preparing a magnesium alloy-hydroxyapatite composite bone prosthesis. This method fully combines the advantages of 3D printing and pressureless infiltration technology with the characteristics of metal-ceramic gradient materials, resulting in a bone prosthesis with excellent performance. For example, the ossicular prosthesis prepared using this invention has the advantages of stable positioning and resistance to displacement and dislodgement, high sound conduction efficiency, controllable cost, and the ability to be customized. It can provide patients with personalized ossicular prostheses with better overall performance, thereby improving the patient's hearing recovery effect and applicability in different scenarios.

[0007] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," "consisting of," etc., and similar meanings.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a method for preparing a magnesium alloy-hydroxyapatite composite bone prosthesis, comprising the following steps:

[0009] S1. Shape feature extraction: Obtain a three-dimensional model containing external and internal structures by scanning the target skeleton with CT.

[0010] S2. Three-dimensional modeling of hydroxyapatite scaffold: The external structure of the three-dimensional bone model is simplified and its internal porous structure is imitated to design the three-dimensional structure of the bone prosthesis.

[0011] S3. Preparation of printing materials, including the preparation of hydroxyapatite printing paste;

[0012] S4. Using stereolithography, a hydroxyapatite scaffold is printed according to the three-dimensional structure of the bone prosthesis.

[0013] S5. Degreasing and sintering of hydroxyapatite scaffold: The hydroxyapatite scaffold is cleaned, degreased, and sintered at high temperature.

[0014] S6. Magnesium alloy smelting and casting: molten magnesium alloy is injected into a hydroxyapatite support using pressureless infiltration technology.

[0015] S7. Post-processing: Use cutting tools to remove excess material (hydroxyapatite and magnesium alloy), and polish to obtain magnesium alloy-hydroxyapatite composite bone prosthesis.

[0016] Furthermore, the bone includes, but is not limited to, the ossicles, meaning that the present invention can prepare a magnesium alloy-hydroxyapatite composite ossicle prosthesis.

[0017] Further, in step S1: a microfocus CT scanner is used for scanning, with a scanning energy of 80-120KV, a slice thickness of 0.1-0.5mm, and a scanning resolution of 10-30μm to clearly capture the details of the ossicles; finally, CT scanning software is used to reconstruct these two-dimensional slice data into three-dimensional images, and a voxel-based reconstruction algorithm (used to obtain internal structures) is used to generate a three-dimensional model.

[0018] Furthermore, in step S2, taking the preparation of an ossicular prosthesis as an example, firstly, the morphological characteristics of the ossicles are analyzed, their geometric shape is simplified, unnecessary structural features are removed, while their basic functional parts are retained to ensure that the ossicular prosthesis can transmit sound vibrations well; then, based on the sparse inner and dense outer structure of the ossicles, a hydroxyapatite scaffold is modeled using three-dimensional modeling software (including but not limited to Materialise Mimics).

[0019] Further, in step S2, taking the preparation of an ossicle prosthesis as an example, the outer layer porosity of the three-dimensional structure of the bone prosthesis is 0, the middle layer porosity is 5-15%, and the inner layer porosity is 50-70%, with the thickness ratio of the outer, middle, and inner layers being 1:2-5:2-5. In addition to the above three-layer gradient, the structure can also be expanded to four, five, or more layers, or even adopt a continuous transition; regardless of the number of layers or the transition form, the porosity increases radially from the outside to the inside (i.e., gradually decreases from the inside to the outside).

[0020] Furthermore, the non-essential structural features include, but are not limited to, surface micro-textures, bony protrusions, and cracks. That is, simplification refers to preserving the functional structure while removing surface micro-textures, bony protrusions, and cracks.

[0021] Further, in step S3, the preparation of the hydroxyapatite printing paste is as follows:

[0022] S31. A mixed UV-curable monomer is obtained by mixing a first UV-curable monomer and a second UV-curable monomer at a mass ratio of 1:1 to 1:5. The first UV-curable monomer is o-phenylphenoxyethyl acrylate (a monofunctional UV-curable monomer, abbreviated as OPPEA) and / or diethylene glycol diacrylate (DEB), and the second UV-curable monomer is 1,6-hexanediol diacrylate (a bifunctional acrylate monomer, 1,6-Hexanedioldiacrylate, abbreviated as HDDA).

[0023] S32. The mixed UV-curable monomer, dispersant, SiO2 and photoinitiator are added to a mixer and stirred. The mass ratio of the UV-curable monomer, dispersant, SiO2 and photoinitiator is 75-90:0.1-0.5:5-15:0.4-2.

[0024] S33. Add hydroxyapatite powder to a mixer and stir until homogeneous to form a hydroxyapatite printing paste with a solid content of 40-60 vol%.

[0025] Further, in step S32, the dispersant is dispersant S18 (trade name Disuper S18) and / or dispersant 350 (trade name E-Sperse 350).

[0026] Further, in step S32, the photoinitiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) and / or 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (BME).

[0027] Furthermore, in step S32, the stirring time is 5-8 hours.

[0028] Further, in step S4: the three-dimensional structure of the bone prosthesis is exported as an STL format, and sliced ​​using slicing software. A stereolithography (SLA) printer is used to print a hydroxyapatite scaffold based on the three-dimensional structure of the bone prosthesis, with the laser power set to 20-50mW, the laser spot spacing to 30-100μm, the laser scanning speed to 5000-9000mm / s, and the layer thickness to 25-50μm.

[0029] Further, in step S5, the hydroxyapatite scaffold is cleaned using alcohol.

[0030] Further, in step S5, the hydroxyapatite scaffold is heated to 100-150°C for degreasing.

[0031] Furthermore, in step S5, the heating rate for degreasing is 0.3-0.8℃ / min.

[0032] Furthermore, in step S5, the high-temperature sintering temperature is 1200-1300℃, and the sintering time is 1-2 hours.

[0033] Furthermore, in step S5, the heating rate of the high-temperature sintering is 1-3℃ / min.

[0034] Furthermore, in step S5, the material is sintered at high temperature and then naturally cooled to room temperature.

[0035] Further, in step S6, the volume ratio of the molten magnesium alloy to the hydroxyapatite support is 70-95:5-30.

[0036] Furthermore, in step S6, injecting molten magnesium alloy into the hydroxyapatite scaffold using pressureless infiltration technology includes the following steps:

[0037] S61. Under a CO2-0.5% SF6 gas atmosphere, melt the magnesium alloy at 750-800℃ using an electric furnace;

[0038] S62. Place the molten magnesium alloy and the hydroxyapatite support together into the vacuum induction furnace, ensuring that the pouring cup of the hydroxyapatite support is aligned with the pouring port of the crucible.

[0039] S63. Vacuuming and heating are performed to maintain the temperature at 700-800℃, completing pressureless impregnation and achieving dense composite molding of magnesium alloy and hydroxyapatite scaffold, with a preferred porosity of ≤5%.

[0040] Further, in step S63, a vacuum is drawn to 10. -3 -10 -2 Pa.

[0041] Furthermore, the impregnation time for step S63, which involves pressureless impregnation, is 20-60 minutes.

[0042] Furthermore, the magnesium alloy is AZ91D magnesium alloy, ZK60 magnesium alloy, or WE43 magnesium alloy.

[0043] Furthermore, in step S7, the excess material refers to the excess hydroxyapatite and magnesium alloy material on the outside of the scaffold. After grinding and polishing, the roughness of the magnesium alloy-hydroxyapatite composite bone prosthesis is lower than Ra0.025.

[0044] Another objective of this invention is to disclose a magnesium alloy-hydroxyapatite composite bone prosthesis prepared using the above-described preparation method.

[0045] Another objective of this invention is to disclose a magnesium alloy-hydroxyapatite composite ossicle prosthesis prepared using the above-described preparation method.

[0046] The magnesium alloy-hydroxyapatite composite bone prosthesis and its preparation method of the present invention have the following advantages compared with the prior art:

[0047] 1) Hydroxyapatite (HA) is a bioceramic material highly similar in composition to natural bone minerals. It exhibits excellent biocompatibility, promotes tissue growth, and its mechanical-acoustic-biological properties are close to those of natural ossicles, making it the optimal material for ossicular prostheses. Magnesium alloy is also a commonly used implant, possessing good toughness, strength, fatigue resistance, good biocompatibility, strong osteoinductive ability, biodegradability, low elastic modulus, and good processing performance. Combining these two materials simultaneously achieves the advantages of toughness, strength, bone growth promotion, similar mechanical properties, and good sound conduction. The degradation rate can be adjusted by changing the ratio of magnesium to hydroxyapatite, allowing the composite prosthesis to provide support and functionality in the early stages. As the magnesium alloy degrades and autologous bone tissue grows, the autologous bone occupies the original position of the Mg alloy, which is beneficial for ossicular fixation and overall performance improvement.

[0048] 2) This invention employs stereolithography (SLA) additive manufacturing technology, which enables the high-precision, high-quality printing of complex porous hydroxyapatite structures. This feature allows for the precise design and fabrication of ossicular prostheses based on the individualized needs of patients, resulting in a higher degree of fit between the prosthesis and the human ear.

[0049] 3) This invention combines pressureless impregnation of magnesium alloys, which can make the magnesium alloy fill the pores uniformly and without damaging the hydroxyapatite skeleton, and without the risk of stress concentration, thus achieving a good combination of the two.

[0050] 4) This invention mimics the morphology of the cortex and cancellous bone of the human natural auditory ossicles, providing a certain degree of shock resistance and cushioning, and improving sound conduction.

[0051] 5) The magnesium alloy-hydroxyapatite composite bone prosthesis prepared by this invention is inexpensive. Taking the preparation of ossicular prostheses as an example, titanium alloy ossicular prostheses cost around 5,000 yuan and are dependent on imports. The ossicular prosthesis prepared by the method of this invention costs around 1,000 yuan, which is 1 / 5 of the price of titanium alloy ossicular prostheses, and can be completely domestically produced. The preparation process is simple and does not require complex processing techniques.

[0052] The method for preparing magnesium alloy-hydroxyapatite composite bone prostheses using additive manufacturing and pressureless infiltration has good application prospects and large-scale promotion potential in the field of bone prostheses. Attached Figure Description

[0053] Figure 1 This is a process flow diagram of the present invention.

[0054] Figure 2 This invention uses SLA technology to print the HA process diagram.

[0055] Figure 3 This is a flow chart of the pressureless permeation process in this invention.

[0056] Figure 4 This is a schematic diagram of the pressureless impregnation magnesium alloy of the present invention.

[0057] Figure 5 This is a schematic diagram of the HA / magnesium alloy composite ossicle structure prepared according to the present invention.

[0058] Among them, 1—simplified ossicles; 2—hydroxyapatite; 3—magnesium alloy; 4—gradient porous structure. Detailed Implementation

[0059] The following description of the technical features is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0060] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0061] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0062] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0063] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0064] In this specification, the terms "optional" or "optional" are used to indicate the use or omission of certain substances, components, procedures, application conditions, etc.

[0065] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0066] Unless otherwise specified, all reagents or instruments used in this instruction manual are commercially available products.

[0067] See Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 This invention provides a preferred embodiment of a magnesium alloy-hydroxyapatite composite ossicular prosthesis and method based on additive manufacturing and pressureless infiltration. The invention first obtains the three-dimensional morphology of human ossicles through CT scanning, then prepares a gradient porous HA framework using 3D printing. Subsequently, pressureless infiltration technology is used to spontaneously infiltrate high-temperature magnesium alloy into the preform, and after cooling, a composite ossicular prosthesis combining metal and reinforcement is formed. This invention fully utilizes the advantages of 3D printing and the characteristics of metal-ceramic gradient materials to provide a novel ossicular prosthesis that solves the problems of easy dislocation, easy infection, poor sound conduction, and inability to be customized in existing ossicular prostheses. It allows for personalized customization of ossicular prostheses with superior overall performance, improving patients' hearing recovery ability and applicability in various scenarios.

[0068] The present invention will be further described below with reference to embodiments.

[0069] Example 1:

[0070] This embodiment discloses a method for preparing a magnesium alloy-hydroxyapatite composite ossicle prosthesis, such as... Figure 1 As shown, it includes the following steps:

[0071] Step 1: Morphological Feature Extraction. A microfocus CT scanner was used for scanning, with a scan energy of 90 kV, a slice thickness of 0.2 mm, and a scan resolution of 15 μm to clearly capture the details of the ossicles. Finally, CT scanning software was used to reconstruct these two-dimensional slice data into three-dimensional images, and a voxel-based reconstruction algorithm was employed to generate a three-dimensional model of the ossicles.

[0072] Step 2: 3D Modeling of the HA Scaffold. First, the morphological characteristics of the ossicles are analyzed, simplifying their geometry and removing unnecessary structural features such as surface micro-textures, bony protrusions, and cracks, while retaining their basic functional components to ensure the prosthesis can effectively transmit sound vibrations. Finally, based on the ossicle's internal sparse-outer-dense structure (0 porosity in the outer layer, 5% porosity in the middle layer, and 60% porosity in the inner layer), the thickness ratio of the outer, middle, and inner layers is 1:5:3. The HA scaffold is then modeled using 3D modeling software.

[0073] Step 3: Preparation of printing materials. First, two UV-curable monomers—OPPEA and HDDA—are mixed in a 1:1 mass ratio. Then, HDDA, OPPEA, dispersant S18, SiO2, and photoinitiator TPO are added to a mixer and stirred for 6 hours, achieving a mass ratio of 88.8:0.2:9:2 for the UV-curable monomers (HDDA and OPPEA), dispersant, SiO2, and photoinitiator. HA powder is then added to the mixer and stirred until homogeneous, forming a slurry with a 50 vol% solids content.

[0074] Step 4: Print the hydroxyapatite (HA) scaffold using stereolithography (SLA). Export the designed 3D model as an STL file and slice it using slicing software. Print the HA scaffold using a stereolithography (SLA) printer, setting the laser power to 30mW, laser spot spacing to 50μm, laser scanning speed to 6000mm / s, and layer thickness to 50μm. The printing process is as follows: Figure 2 As shown.

[0075] Step 5: Degreasing and Sintering of the HA Scaffold. The printed green preform is cleaned with alcohol and degreased by heating at a rate of 0.5℃ / min while maintaining the temperature at 120℃. Direct sintering is then performed at a heating rate of 1℃ / min, held at 1200℃ for 1 hour, and allowed to cool naturally to room temperature.

[0076] Step 6: Melt the AZ91D magnesium alloy at 750℃ using an electric furnace under a CO2-0.5% SF6 gas atmosphere. Once the magnesium alloy is completely molten, place it together with the pre-sintered billet into a vacuum induction furnace, ensuring the billet's pouring cup is aligned with the crucible's pouring gate. Evacuate to 10... -3 -10 -2 Pa is then applied and heating is initiated, maintaining the temperature at 700℃. Pressureless impregnation is performed for 30 minutes to achieve a dense composite molding of the magnesium alloy and the preform. The flowchart and schematic diagram are shown below. Figure 3 and 4 As shown.

[0077] Step 7: Post-processing. Use a cutting machine to remove excess hydroxyapatite and magnesium alloy to obtain the ossicular prosthesis blank. Use sandpaper and polishing cloth to grind and polish the ossicular prosthesis blank until the roughness is below Ra0.025. The resulting magnesium alloy-hydroxyapatite composite ossicular prosthesis structure is shown below. Figure 5 As shown.

[0078] Example 2:

[0079] This embodiment discloses a method for preparing a magnesium alloy-hydroxyapatite composite ossicle prosthesis, including the following steps:

[0080] Step 1: Morphological Feature Extraction. A microfocus CT scanner was used for scanning, with a scan energy of 100 kV, a slice thickness of 0.3 mm, and a scan resolution of 20 μm to clearly capture the details of the ossicles. Finally, CT scanning software was used to reconstruct these two-dimensional slice data into three-dimensional images, and a voxel-based reconstruction algorithm was employed to generate a three-dimensional model of the ossicles.

[0081] Step 2: 3D Modeling of the HA Scaffold. First, the morphological characteristics of the ossicles are analyzed, simplifying their geometry and removing unnecessary structural features such as surface micro-textures, bony protrusions, and cracks, while retaining their basic functional components to ensure the prosthesis can effectively transmit sound vibrations. Finally, based on the ossicle's internal sparse-outer-dense structure (0 porosity in the outer layer, 5% porosity in the middle layer, and 58% porosity in the inner layer), the thickness ratio of the outer, middle, and inner layers is 1:5:3. The HA scaffold is then modeled using 3D modeling software.

[0082] Step 3: Preparation of printing materials. First, two UV-curable monomers—DEB and HDDA—are mixed at a mass ratio of 1:3. Then, HDDA, DEB, 0.3 wt% dispersant 350, 9 wt% SiO2, and photoinitiator TPO are added to a mixer and stirred for 6 hours, resulting in a mass ratio of UV-curable monomers (DEB and HDDA), dispersant, SiO2, and photoinitiator of 90:0.3:9:0.7. HA powder is then added to the mixer and stirred until homogeneous, forming a slurry with a 50 vol% solids content.

[0083] Step 4: Print the hydroxyapatite (HA) scaffold using stereolithography (SLA). Export the designed 3D model as an STL file and slice it using slicing software. Print the HA scaffold using a stereolithography (SLA) printer, setting the laser power to 20mW, laser spot spacing to 60μm, laser scanning speed to 7000mm / s, and layer thickness to 30μm. The printing process is as follows: Figure 2 As shown.

[0084] Step 5: Degreasing and Sintering of the HA Scaffold. The printed green preform is cleaned with alcohol and degreased by maintaining the temperature at 130°C at a heating rate of 0.6°C / min. Direct sintering is then performed at a heating rate of 1°C / min, held at 1300°C for 1 hour, and allowed to cool naturally to room temperature.

[0085] Step 6: Melt the AZ91D magnesium alloy at 780℃ using an electric furnace under a CO2-0.5% SF6 gas atmosphere. Once the magnesium alloy is completely molten, place it together with the pre-sintered billet into a vacuum induction furnace, ensuring the billet's pouring cup is aligned with the crucible's pouring gate. Evacuate to 10... -3-10 -2 Pa is then applied and heating is initiated, maintaining the temperature at 800℃. Pressureless impregnation is performed for 20 minutes to achieve a dense composite molding of the magnesium alloy and the preform. The flowchart and schematic diagram are as follows: Figure 3 and 4 As shown.

[0086] Step 7: Post-processing. Use a cutting machine to remove excess hydroxyapatite and magnesium alloy to obtain the ossicular prosthesis blank. Use sandpaper and polishing cloth to grind and polish the ossicular prosthesis blank until the roughness is below Ra 0.025. The final composite ossicular structure is as follows: Figure 5 As shown.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a magnesium alloy-hydroxyapatite composite bone prosthesis, characterized in that, Includes the following steps: S1. Obtain a three-dimensional model containing the external and internal structures by scanning the target skeleton with CT. S2. Simplify the external structure of the 3D model of the skeleton and imitate its internal porous structure to design the 3D structure of the bone prosthesis. S3. Preparation of hydroxyapatite printing paste; S4. Using stereolithography, a hydroxyapatite scaffold is printed according to the three-dimensional structure of the bone prosthesis. S5. The hydroxyapatite scaffold is cleaned, degreased, and sintered at high temperature. S6. Use pressureless infiltration technology to inject molten magnesium alloy into a hydroxyapatite scaffold; S7. Use cutting tools to remove excess material and polish to obtain magnesium alloy-hydroxyapatite composite bone prosthesis.

2. The method for preparing the magnesium alloy-hydroxyapatite composite bone prosthesis according to claim 1, characterized in that, The bone in question is the auditory ossicle.

3. The method for preparing the magnesium alloy-hydroxyapatite composite bone prosthesis according to claim 1 or 2, characterized in that, In step S1: a microfocus CT scanner is used for scanning, with a scanning energy of 80-120kV, a slice thickness of 0.1-0.5mm, and a scanning resolution of 10-30μm. Finally, CT scanning software is used to reconstruct these two-dimensional slice data into three-dimensional images, and a voxel-based reconstruction algorithm is used to generate a three-dimensional model.

4. The method for preparing the magnesium alloy-hydroxyapatite composite bone prosthesis according to claim 1 or 2, characterized in that, In step S2, firstly, the morphological characteristics of the ossicles are analyzed, their geometric shape is simplified, and unnecessary structural features are removed, while retaining their basic functional parts to ensure that the ossicle prosthesis can transmit sound vibrations well; then, based on the sparse inner and dense outer structure of the ossicles, a hydroxyapatite scaffold is modeled using three-dimensional modeling software.

5. The method for preparing the magnesium alloy-hydroxyapatite composite bone prosthesis according to claim 1 or 2, characterized in that, In step S3, the steps for preparing the hydroxyapatite printing paste are as follows: S31. A mixed UV-curable monomer is obtained by mixing a first UV-curable monomer and a second UV-curable monomer in a mass ratio of 1:1 to 1:

5. The first UV-curable monomer is o-phenylphenoxyethyl acrylate and / or diethylene glycol diacrylate, and the second UV-curable monomer is 1,6-hexanediol diacrylate. S32. The mixed UV-curable monomer, dispersant, SiO2 and photoinitiator are added to a mixer and stirred. The mass ratio of the UV-curable monomer, dispersant, SiO2 and photoinitiator is 75-90:0.1-0.5:5-15:0.4-2. S33. Add hydroxyapatite powder to a mixer and stir until homogeneous to form a hydroxyapatite printing slurry with a solid content of 40-60 vol%. The dispersant is dispersant S18 and / or dispersant 350; The photoinitiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and / or 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone.

6. The method for preparing the magnesium alloy-hydroxyapatite composite bone prosthesis according to claim 1 or 2, characterized in that, In step S4: A stereolithography printer is used to print a hydroxyapatite scaffold according to the three-dimensional structure of the bone prosthesis. The laser power is set to 20-50mW, the laser spot spacing is set to 30-100μm, the laser scanning speed is set to 5000-9000mm / s, and the layer thickness is set to 25-50μm.

7. The method for preparing the magnesium alloy-hydroxyapatite composite bone prosthesis according to claim 1 or 2, characterized in that, In step S5, the hydroxyapatite scaffold is cleaned with alcohol. And / or, the hydroxyapatite scaffold is heated to 100-150°C for degreasing; And / or, the heating rate for the degreasing process is 0.3-0.8℃ / min; And / or, the high-temperature sintering temperature is 1200-1300℃, and the sintering time is 1-2 hours; And / or, the heating rate of the high-temperature sintering is 1-3℃ / min; And / or, after high-temperature sintering, naturally cool to room temperature.

8. The method for preparing the magnesium alloy-hydroxyapatite composite bone prosthesis according to claim 1 or 2, characterized in that, Step S6, injecting molten magnesium alloy into the hydroxyapatite scaffold using pressureless infiltration technology, includes the following steps: S61. Under a CO2-0.5%SF6 gas atmosphere, the magnesium alloy is melted in an electric furnace at 750-800℃. S62. Place the molten magnesium alloy and the hydroxyapatite support together into the vacuum induction furnace, ensuring that the pouring cup of the hydroxyapatite support is aligned with the pouring port of the crucible. S63. Vacuuming and heating are performed to maintain the temperature at 700-800℃, completing pressureless impregnation and achieving dense composite molding of magnesium alloy and hydroxyapatite scaffold.

9. A magnesium alloy-hydroxyapatite composite bone prosthesis, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.

10. A magnesium alloy-hydroxyapatite composite ossicle prosthesis, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.

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