A biomimetic ceramic bone repair scaffold and a preparation method thereof

Abstract

The application discloses a kind of bionic ceramic bone repair scaffolds and preparation method thereof, belong to biomedical material and biological manufacturing technical field, the original data is obtained by micro-CT scanning echinoderm skeleton, porous structure is extracted and three-dimensional model is established, after finite element stress analysis and structure optimization, it is imported into photocuring three-dimensional printing equipment;Carbonate calcium powder is synthesized using wet chemical method and is prepared into ceramic slurry with photosensitive resin premix liquid, the scaffold green body is prepared by photocuring three-dimensional printing, then defatting and high-temperature sintering under carbon dioxide atmosphere, obtain bionic ceramic bone repair scaffold.The scaffold imitates the porous structure and chemical composition of echinoderm skeleton, porosity, pore size and compressive strength can be adjusted, with high mechanical strength, moderate degradation rate, excellent biocompatibility and bone regeneration activity and other advantages.

Description

Technical Field

[0001] This invention relates to the fields of biomedical materials and biomanufacturing technology, specifically to a biomimetic ceramic bone repair scaffold and its preparation method. Background Technology

[0002] Bone defect repair is one of the challenges faced by clinical orthopedic surgeons. Calcium phosphate ceramic scaffolds, with a composition similar to human bone tissue, possess excellent biocompatibility and osteoconductivity, making them the most commonly used synthetic bone repair material. However, calcium phosphate has a slow degradation rate, which is mismatched with the rate of new bone ingrowth. Furthermore, due to the inherent brittleness of ceramics, stress concentration causes the mechanical strength of the ceramic scaffold to decrease sharply with increasing porosity, pore size, and pore connectivity. The porosity of calcium phosphate bone repair scaffolds is typically above 50%, making it difficult to meet the mechanical strength requirements for weight-bearing bone defects. This compromises the interfacial stability between the implant and the host bone, hinders sufficient mechanical stimulation for bone regeneration, impedes bone integration, and easily leads to nonunion. While reducing porosity can improve the mechanical strength of the scaffold, this compromises its biological properties. Therefore, the existing calcium phosphate ceramic scaffolds present an irreconcilable contradiction between degradation rate and mechanical strength, limiting their application in the repair of weight-bearing bone defects.

[0003] Studies have found that the main component of echinoderm skeletons is magnesium calcium carbonate, with a porosity as high as 60% to 80%. Although magnesium calcium carbonate has a relatively low specific strength, the compressive strength of sea urchin and starfish skeletons is much higher than that of randomly porous alumina ceramics and octagonal truss-structured silica ceramics. This is mainly due to their unique gradient porous structure, which effectively avoids significant stress concentration. Calcium carbonate materials possess excellent biocompatibility and osteoconductivity, with a moderate degradation rate, slightly faster than calcium phosphate materials, matching the ingrowth rate of new bone tissue. Magnesium ions participate in multiple physiological processes such as bone tissue formation, bone metabolism regulation, and bone mineral crystallization, promoting the differentiation of bone marrow mesenchymal stem cells into osteocytes, and still exhibiting good biocompatibility at high concentrations. Therefore, through biomimetic simulation of the structure and composition of echinoderm skeletons, it is hoped that ceramic bone repair scaffolds with high strength, high porosity, suitable degradation rate, and excellent osteogenic and angiogenic properties can be developed. Therefore, how to provide a biomimetic ceramic bone repair scaffold that can simultaneously achieve high strength, high porosity, degradation rate and bone regeneration and its preparation method has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] To address the problems mentioned in the background section, this invention provides a biomimetic ceramic bone repair scaffold and its preparation method. The technical solution adopted by this invention is as follows: A method for preparing a biomimetic ceramic bone repair scaffold, characterized by comprising the following steps: S10: Obtain the raw scan information of the echinoderm skeleton, and preprocess the raw scan information and extract the porous structure to establish the initial three-dimensional model information; S20: Perform stress analysis on the initial three-dimensional model information, and adjust the porous structure parameters according to the analysis results to reduce stress concentration, thereby generating optimized three-dimensional model information; S30: Import the optimized three-dimensional model information into the photopolymerization three-dimensional printing equipment, and use the photopolymerization three-dimensional printing process to print the magnesium calcium carbonate photosensitive ceramic slurry to generate a bracket green body; S40: Degrease the scaffold blank to generate a scaffold preform; S50: The scaffold blank is sintered at high temperature in a carbon dioxide atmosphere to generate a biomimetic ceramic bone repair scaffold material.

[0005] In a preferred embodiment, this application can be further configured such that step S10 specifically includes: S101: Micro-CT scans of echinoderms' skeletons were used to obtain raw DICOM data. S102: Perform isotropic voxel resampling, window width and window level adjustment, and noise reduction on the original DICOM data information to generate preprocessed image information; S103: Segment and extract the porous structure from the preprocessed image information, and export the three-dimensional mesh model information; S104: Perform topology repair, surface smoothing and mesh quality optimization on the three-dimensional mesh model information to generate the initial three-dimensional model information.

[0006] In a preferred embodiment, this application can be further configured such that step S20 specifically includes: S201: Apply preset loading conditions to the initial three-dimensional model information, perform finite element stress analysis, and generate stress distribution information; S202: Based on the stress distribution information, the pore size, wall thickness and distribution parameters of the porous structure are adjusted by genetic algorithm or topology optimization method to reduce stress concentration and generate the optimized three-dimensional model information.

[0007] In a preferred embodiment, this application can be further configured such that step S30 specifically includes: S301: Magnesium calcium carbonate powder is synthesized using a wet chemical method. The chemical formula of the magnesium calcium carbonate is: , where x ranges from 0.01 to 0.99; S302: The magnesium calcium carbonate powder is uniformly mixed with the photosensitive resin premix, and then ball-milled to generate the magnesium calcium carbonate photosensitive ceramic slurry. S303: Place the magnesium calcium carbonate photosensitive ceramic slurry into the slurry tank of the photocuring 3D printing equipment, and import the optimized 3D model information into the photocuring 3D printing equipment; S304: The scaffold blank with a porous structure mimicking the skeleton of an echinoderm was prepared using a photopolymerization 3D printing process.

[0008] In a preferred embodiment, this application may be further configured such that the wet chemical process in step S301 uses a calcium source, a magnesium source, and a carbonate source for the reaction, wherein the calcium source is one of calcium nitrate, calcium chloride, or calcium acetate, the magnesium source is one of magnesium nitrate, magnesium chloride, or magnesium acetate, and the carbonate source is one of sodium carbonate or potassium carbonate.

[0009] In a preferred embodiment, this application may be further configured such that: the photosensitive resin premix in step S302 includes a prepolymer, a dispersant, a diluent, and a photoinitiator; and the solid content of the magnesium calcium carbonate photosensitive ceramic slurry is 30% to 80%.

[0010] In a preferred embodiment, this application may be further configured such that the degreasing temperature in step S40 is 400°C to 650°C, and the holding time is 1 to 24 hours.

[0011] In a preferred embodiment, this application may be further configured such that: the partial pressure of the carbon dioxide atmosphere in step S50 is 0.1 to 10 MPa, the temperature of the high-temperature sintering is 800°C to 1100°C, and the holding time is 0.5 to 6 hours.

[0012] In a preferred embodiment, the present application may be further configured such that the biomimetic ceramic bone repair scaffold mimics the porous structure and chemical composition of echinoderm bones, having a porosity of 30% to 80%, a pore size of 50 to 800 μm, and a compressive strength of 1.0 to 150 MPa.

[0013] In a preferred embodiment, this application can be further configured such that: the chemical composition of the biomimetic ceramic bone repair scaffold is selected from the chemical composition of starfish or sea urchin skeletons, specifically magnesium calcium carbonate, with the chemical formula [chemical formula missing]. , where x ranges from 0.01 to 0.99.

[0014] The beneficial effects of the biomimetic ceramic bone repair scaffold and its preparation method of the present invention are as follows: By employing high-fidelity digital biomimicry of the gradient porous structure of echinoderm bones and combining finite element stress analysis with genetic algorithms or topology optimization methods for mechanical optimization of the porous structure, stress concentration points are effectively eliminated. This allows the scaffold to achieve significantly improved compressive strength while maintaining high porosity, resolving the contradiction between porosity and mechanical strength in traditional calcium phosphate scaffolds. Furthermore, using magnesium calcium carbonate as the scaffold material ensures that its degradation rate matches the ingrowth rate of new bone tissue, avoiding the problem of delayed bone healing caused by slow calcium phosphate degradation. The magnesium ions released during degradation promote the differentiation of bone marrow mesenchymal stem cells into osteocytes and the proliferation and differentiation of angiogenic cells, thereby achieving efficient in-situ bone regeneration and vascularization. In addition, the magnesium calcium carbonate photosensitive ceramic slurry is precisely molded using a photopolymerization 3D printing process, enabling programmable control of pore size, porosity, and three-dimensional interconnected structure. This allows for personalized customization to meet the mechanical and biological needs of bone defects in different locations. This invention effectively solves the technical problems of mismatched degradation rate and insufficient mechanical strength of existing calcium phosphate ceramic bone repair scaffolds, and provides a biomimetic ceramic bone repair scaffold solution with high strength, high porosity, suitable degradation rate and excellent osteogenic activity for the repair of bone defects in load-bearing parts. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating an embodiment of the biomimetic ceramic bone repair scaffold and its preparation method according to this application. Figure 2 This is a flowchart illustrating step S10 in an embodiment of a biomimetic ceramic bone repair scaffold and its preparation method according to this application. Figure 3 This is a flowchart illustrating step S30 in an embodiment of a biomimetic ceramic bone repair scaffold and its preparation method according to this application. Figure 4 This is a model diagram of the porous structure of a biomimetic ceramic bone repair scaffold and its preparation method, based on the sea urchin motif of this application.

[0016] Figure 5 This is a stereomicrograph of a biomimetic ceramic bone repair scaffold with a porous, sea urchin-like structure, which is the basis of the present application and its preparation method. Detailed Implementation

[0017] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] As attached Figure 1-3 As shown, a method for preparing a biomimetic ceramic bone repair scaffold is characterized by the following steps: S10: Obtain the raw scan information of the echinoderm skeleton, and preprocess the raw scan information and extract the porous structure to establish the initial three-dimensional model information; S20: Perform stress analysis on the initial three-dimensional model information, and adjust the porous structure parameters according to the analysis results to reduce stress concentration, thereby generating optimized three-dimensional model information; S30: Import the optimized three-dimensional model information into the photopolymerization three-dimensional printing equipment, and use the photopolymerization three-dimensional printing process to print the magnesium calcium carbonate photosensitive ceramic slurry to generate a bracket green body; S40: Degrease the scaffold blank to generate a scaffold preform; S50: The scaffold blank is sintered at high temperature in a carbon dioxide atmosphere to generate a biomimetic ceramic bone repair scaffold material.

[0019] In this embodiment, the original scan information is a set of original two-dimensional slice image data obtained after tomographic scanning of echinoderm bones using a micro-CT device; porous structure extraction is a binarization process that segments the internal pores and solid regions of the bone from the preprocessed images; the initial three-dimensional model information is an unoptimized three-dimensional mesh model reconstructed based on the extracted porous structure; stress analysis is the calculation of the stress distribution state of the three-dimensional model under stress conditions using the finite element method; the optimized three-dimensional model information is a three-dimensional mesh model with significantly reduced stress concentration after structural parameter adjustment; and the photopolymerization three-dimensional printing equipment is an additive manufacturing device that uses digital light projection or stereolithography technology to cure photosensitive materials layer by layer. Magnesium carbonate calcium photosensitive ceramic slurry is a uniform suspension containing magnesium carbonate calcium ceramic powder and photosensitive resin premix; the scaffold green body is a polymer-ceramic composite formed by photocuring but not degreased and sintered; degreasing treatment is a process of removing organic matter from the green body by thermal decomposition through heating; the scaffold blank is a porous body that retains only the ceramic powder skeleton after degreasing; carbon dioxide atmosphere is a carbon dioxide-containing gas environment used to inhibit carbonate decomposition during sintering; high-temperature sintering is a heat treatment process that forms a dense connection by allowing material diffusion between ceramic particles at high temperature; the biomimetic ceramic bone repair scaffold material is the final obtained porous ceramic body with the biomimetic structure of echinoderm bones and the chemical composition of magnesium carbonate calcium.

[0020] Specifically, the process begins by acquiring raw scan information of echinoderm skeletons and establishing an initial 3D model through preprocessing and porous structure extraction, thus transforming the natural biological structure into an editable digital model. Next, stress analysis is performed on the initial 3D model, and parameters such as pore size, wall thickness, and distribution of the porous structure are adjusted based on the analysis results to reduce stress concentration, generating an optimized 3D model that achieves a more uniform stress distribution while maintaining high porosity. The optimized 3D model is then imported into a photopolymerization 3D printing device, where a magnesium-calcium carbonate photosensitive ceramic slurry is printed using photopolymerization technology to create a scaffold green body, achieving precise molding of the complex biomimetic porous structure. The scaffold green body is then degreased to remove organic matter, resulting in a scaffold blank containing only a ceramic skeleton. Finally, the scaffold blank is sintered at high temperature in a carbon dioxide atmosphere to generate a biomimetic ceramic bone repair scaffold material. The atmosphere protection prevents the decomposition of magnesium-calcium carbonate at high temperatures and simultaneously forms strong sintering necks between ceramic particles. This method combines digital biomimetic design with additive manufacturing technology to produce ceramic bone repair scaffolds with both high porosity and excellent mechanical properties. It effectively solves the dual problems of mismatched degradation rate and insufficient mechanical strength of traditional calcium phosphate scaffolds. At the same time, the released magnesium ions also have the biological function of promoting osteogenic and angiogenesis.

[0021] In one embodiment, step S10 specifically includes: S101: Micro-CT scans of echinoderms' skeletons were used to obtain raw DICOM data. S102: Perform isotropic voxel resampling, window width and window level adjustment, and noise reduction on the original DICOM data information to generate preprocessed image information; S103: Segment and extract the porous structure from the preprocessed image information, and export the three-dimensional mesh model information; S104: Perform topology repair, surface smoothing and mesh quality optimization on the three-dimensional mesh model information to generate the initial three-dimensional model information.

[0022] In this embodiment, micro-CT scanning is a non-destructive testing method that uses X-ray micro-computed tomography to obtain the three-dimensional structure inside a sample; the original DICOM data information is the original slice image data generated by micro-CT scanning that conforms to the medical digital image communication standard; isotropic voxel resampling is the operation of resampling voxels with inconsistent resolution in different directions into isotropic voxels; window width and window level adjustment is the operation of adjusting the grayscale image display range to optimize the contrast between bones and pores; preprocessed image information is the image data with improved quality after resampling, window level adjustment, and noise reduction; segmentation extraction is the operation of separating the pore region from the bone entity region in the image based on the grayscale threshold; the three-dimensional mesh model information is the surface mesh data composed of triangular facets; topology repair is the operation of correcting topological defects such as holes and non-manifold edges in the mesh model; surface smoothing is the filtering operation to eliminate the stepped artifacts on the mesh surface; and mesh quality optimization is the operation of adjusting the shape and size of triangles to improve mesh uniformity.

[0023] Specifically, the process begins with micro-CT scanning of echinoderms' skeletons to acquire raw DICOM data, obtaining detailed structural data of the bone's interior in a non-destructive manner. Then, isotropic voxel resampling is performed on the raw DICOM data to ensure consistent resolution across all directions, window width and level adjustments optimize image contrast, and denoising eliminates random noise, generating preprocessed image information that lays the foundation for accurate segmentation. Next, porous structures are extracted from the preprocessed images, and 3D mesh model information is exported, converting the image data into an editable surface mesh. Finally, topology repair is performed on the 3D mesh model to eliminate defects, surface smoothing to remove artifacts, and mesh quality optimization to improve uniformity, generating initial 3D model information. This workflow, through systematic image processing and model optimization operations, faithfully transforms the complex porous structure of natural bone into a digital model suitable for subsequent analysis and printing, ensuring the accurate inheritance of the biomimetic structure.

[0024] In one embodiment, step S20 specifically includes: S201: Apply preset loading conditions to the initial three-dimensional model information, perform finite element stress analysis, and generate stress distribution information; S202: Based on the stress distribution information, the pore size, wall thickness and distribution parameters of the porous structure are adjusted by genetic algorithm or topology optimization method to reduce stress concentration and generate the optimized three-dimensional model information.

[0025] In this embodiment, the preset loading conditions are the boundary conditions and load magnitudes set to simulate the actual stress conditions of the bone repair scaffold; the finite element stress analysis is to calculate the stress and deformation distribution of the model after being subjected to force by numerically solving partial differential equations; the stress distribution information is the spatial distribution data of the stress magnitude at each location of the model; the genetic algorithm is an iterative optimization algorithm that simulates the natural evolution process, searching for the optimal structural parameters through selection, crossover, and mutation operations; the topology optimization method is a mathematical optimization method to find the optimal material distribution within a given design domain; the pore size is the characteristic size of the pores in the porous structure; the wall thickness is the thickness of the porous structure solid support; and the distribution parameters are the arrangement and density distribution of the pores in space.

[0026] Specifically, the initial 3D model is first subjected to preset loading conditions and finite element stress analysis to generate stress distribution information, thereby identifying high-risk areas of stress concentration in the model. Then, based on the stress distribution information, a genetic algorithm is used to search for the optimal combination of structural parameters globally, or a topology optimization method is used to gradually adjust the spatial distribution of the material to reduce peak stress and achieve more uniform stress transmission. This optimization process improves the mechanical response of the structure by adjusting pore size, wall thickness, and distribution parameters, generating optimized 3D model information. The purpose of this step is to use natural biological structures as the initial scheme, and further improve their mechanical properties through a combination of numerical simulation and optimization algorithms, so that the final porous structure can effectively avoid stress concentration even under high porosity conditions, thereby improving the compressive strength and structural reliability of the scaffold.

[0027] In one embodiment, step S30 specifically includes: S301: Magnesium calcium carbonate powder is synthesized using a wet chemical method. The chemical formula of the magnesium calcium carbonate is: , where x ranges from 0.01 to 0.99; S302: The magnesium calcium carbonate powder is uniformly mixed with the photosensitive resin premix, and then ball-milled to generate the magnesium calcium carbonate photosensitive ceramic slurry. S303: Place the magnesium calcium carbonate photosensitive ceramic slurry into the slurry tank of the photocuring 3D printing equipment, and import the optimized 3D model information into the photocuring 3D printing equipment; S304: The scaffold blank with a porous structure mimicking the skeleton of an echinoderm was prepared using a photopolymerization 3D printing process.

[0028] In this embodiment, the wet chemical method is a chemical method for synthesizing solid powders through chemical reactions in solution; the magnesium calcium carbonate powder has the following chemical formula: Micron-sized ceramic powder; photosensitive resin premix information refers to a liquid resin mixture containing prepolymer, monomer, photoinitiator and dispersant; ball milling is an operation that uses grinding media balls in a rotating tank to perform high-energy grinding of slurry to disperse agglomerates; magnesium calcium carbonate photosensitive ceramic slurry is a photocurable suspension formed by uniformly dispersing magnesium calcium carbonate powder in photosensitive resin; slurry tank is a container in photocuring equipment for holding ceramic slurry; photocuring 3D printing process is an additive manufacturing technology that uses ultraviolet light to selectively cure photosensitive resin to build three-dimensional objects layer by layer.

[0029] Specifically, magnesium calcium carbonate powder is first synthesized using a wet chemical method, and a high-purity ceramic raw material with controllable composition is prepared through solution reaction. Then, the magnesium calcium carbonate powder is uniformly mixed with a photosensitive resin premix and ball-milled to generate a magnesium calcium carbonate photosensitive ceramic slurry, allowing the ceramic particles to be fully dispersed in the resin and form a stable suspension system. Next, the slurry is placed in the slurry tank of a photopolymerization 3D printing device, and the optimized 3D model is imported into the device. Finally, the photopolymerization 3D printing process is used to cure the photosensitive resin in the slurry layer by layer, preparing a scaffold green body with a porous structure mimicking the skeleton of an echinoderm. This step, through the combination of high-solids-content ceramic slurry and high-precision photopolymerization printing, achieves the precise molding of complex biomimetic porous structures, accurately replicating various structural parameters of the optimized 3D model.

[0030] In one embodiment, the wet chemical method in step S301 uses a calcium source, a magnesium source, and a carbonate source for reaction. The calcium source is one of calcium nitrate, calcium chloride, or calcium acetate. The magnesium source is one of magnesium nitrate, magnesium chloride, or magnesium acetate. The carbonate source is one of sodium carbonate or potassium carbonate.

[0031] In this embodiment, the calcium source is a soluble calcium salt raw material that provides calcium ions; the magnesium source is a soluble magnesium salt raw material that provides magnesium ions; and the carbonate source is a soluble carbonate raw material that provides carbonate ions.

[0032] Specifically, in the wet chemical synthesis, any one of calcium nitrate, calcium chloride, or calcium acetate can be used as the calcium source; any one of magnesium nitrate, magnesium chloride, or magnesium acetate can be used as the magnesium source; and any one of sodium carbonate or potassium carbonate can be used as the carbonic acid source. All of the above calcium, magnesium, and carbonic acid sources are water-soluble salts, facilitating homogeneous reactions in solution. By rationally combining these raw materials, a co-precipitation reaction of calcium ions, magnesium ions, and carbonate ions can be achieved in solution, producing magnesium-calcium carbonate powder with a uniform chemical composition and conforming to stoichiometric ratios.

[0033] In one embodiment, the photosensitive resin premix in step S302 includes a prepolymer, a dispersant, a diluent, and a photoinitiator; the solid content of the magnesium calcium carbonate photosensitive ceramic slurry is 30% to 80%.

[0034] In this embodiment, the prepolymer is an oligomer component that provides a mechanical framework in the photosensitive resin; the dispersant is a surfactant that improves the dispersion stability of ceramic particles in the resin; the diluent is an active monomer that adjusts the viscosity of the slurry; the photoinitiator is a compound that generates free radicals after absorbing ultraviolet light to initiate a polymerization reaction; and the solid content is the mass percentage of ceramic powder in the total mass of the slurry.

[0035] Specifically, the photosensitive resin premix contains prepolymers to provide the mechanical properties of the cured polymer, dispersants to prevent ceramic particle agglomeration, diluents to adjust the slurry viscosity to a suitable range for printing, and photoinitiators to initiate the polymerization reaction under ultraviolet light irradiation. The magnesium carbonate calcium photosensitive ceramic slurry has a solid content of 30% to 80%. This formulation design ensures that the slurry has both a sufficiently high ceramic powder content to guarantee the density and mechanical strength of the scaffold after sintering, and suitable flowability and photocuring reactivity, thereby meeting the requirements of photocuring 3D printing processes for slurry rheology and molding accuracy.

[0036] In one embodiment, the degreasing temperature in step S40 is 400°C to 650°C, and the holding time is 1 to 24 hours.

[0037] In this embodiment, the degreasing temperature is the heating temperature set during the degreasing process; the holding time is the time maintained at the target temperature.

[0038] Specifically, the degreasing temperature is between 400 and 650 degrees Celsius. Within this temperature range, organic matter such as photosensitive resin in the green body of the support can be fully thermally decomposed and volatilized. The holding time is between one and twenty-four hours, a sufficiently long holding time to ensure complete decomposition of organic matter without leaving any carbides. The design of these process conditions ensures that organic matter is fully removed while significant sintering has not yet occurred between ceramic particles, thus obtaining a pure ceramic skeleton green body, creating favorable conditions for subsequent high-temperature sintering.

[0039] In one embodiment, the partial pressure of the carbon dioxide atmosphere in step S50 is 0.1 to 10 MPa, the temperature of the high-temperature sintering is 800°C to 1100°C, and the holding time is 0.5 to 6 hours.

[0040] In this embodiment, the partial pressure of carbon dioxide atmosphere is the partial pressure value of carbon dioxide gas in sintering atmosphere; the high temperature sintering temperature is the highest heating temperature set during the sintering process; and the holding time is the time maintained at the highest temperature.

[0041] Specifically, the partial pressure of the carbon dioxide atmosphere is 0.1 to 10 MPa. Sintering under this atmosphere effectively inhibits the decomposition reaction of magnesium calcium carbonate at high temperatures, ensuring that the phase composition of the final product is consistent with expectations. The high-temperature sintering temperature is 800 to 1100 degrees Celsius, and the holding time is 0.5 to 6 hours. This temperature range is sufficient to allow sufficient diffusion between ceramic particles to achieve densification sintering, while avoiding excessive grain growth or excessive decomposition of carbonates due to excessive temperature. Combined with the protection of the carbon dioxide atmosphere, a biomimetic ceramic bone repair scaffold with fine grains, pure phase composition, and excellent mechanical properties can be obtained.

[0042] In one embodiment, the biomimetic ceramic bone repair scaffold mimics the porous structure and chemical composition of echinoderm bones, with a porosity of 30% to 80%, a pore size of 50 to 800 μm, and a compressive strength of 1.0 to 150 MPa.

[0043] In this embodiment, the porous structure is a network of interconnected or partially interconnected pores within the support; the porosity is the percentage of pore volume to the total volume of the support; the pore size is the characteristic size of the pores in the porous structure; and the compressive strength is the maximum stress that the support can withstand before failure under compressive load.

[0044] Specifically, this scaffold mimics the porous structure and chemical composition of echinoderm bones, with a porosity of 30% to 80%, which can be precisely controlled according to different clinical needs; a pore size of 50 to 800 micrometers, providing suitable space for bone tissue ingrowth; and a compressive strength of 1.0 to 150 MPa, covering a wide range of clinical needs from non-load-bearing to partially load-bearing areas. This scaffold achieves a synergy of high porosity and high strength through biomimetic design. Simultaneously, the magnesium carbonate calcium component has a moderate degradation rate, matching the ingrowth rate of new bone tissue, and the released magnesium ions also exhibit good osteogenic and angiogenic activity.

[0045] In one embodiment, the chemical composition of the biomimetic ceramic bone repair scaffold is selected from the chemical composition of starfish or sea urchin skeletons, specifically magnesium calcium carbonate, with the chemical formula [chemical formula missing]. , where x ranges from 0.01 to 0.99.

[0046] In this embodiment, the chemical composition of the biomimetic ceramic bone repair scaffold is selected from the chemical composition of starfish or sea urchin skeletons, specifically magnesium calcium carbonate, a natural mineral phase of echinoderm skeletons. The value of x in the magnesium calcium carbonate synthesized by wet chemical methods ranges from 0.01 to 0.99, meaning the molar ratio of calcium to magnesium can be continuously adjusted within a wide range. By adjusting the x value, the degradation rate of the scaffold and the magnesium ion release behavior can be precisely controlled, thereby matching the healing speed requirements of different bone defect sites. This chemical composition ensures both the consistency of the material with the chemical composition of natural echinoderm skeletons and provides flexibility in composition design.

[0047] A specific embodiment of the biomimetic ceramic bone repair scaffold and its preparation method of the present invention is as follows: Example

[0048] (1) High-resolution micro-CT scans were used to obtain raw DICOM data from sea urchin skeletons and preprocess the data. After importing the raw data into Mimics software, isotropic voxel resampling, window width and window level adjustments were performed, and motion artifacts and noise were removed. Subsequently, the porous structure of the echinoderm skeleton was accurately segmented from the grayscale images, and a high-quality STL format 3D mesh model was exported. Topology repair, surface smoothing, and mesh quality optimization were performed on the model. The model was further processed through Boolean operations and mesh simplification. The processed 3D model was imported into MeshLab for mesh optimization and refinement. Then, Abaqus finite element analysis software was used to apply realistic loading conditions to the porous structure to analyze its stress distribution and deformation behavior. Based on the finite element analysis results, the pore size, wall thickness, and distribution of the porous structure were further adjusted in MeshLab using genetic algorithms or topology optimization methods to reduce stress concentration. Finally, the optimized 3D model ( Figure 4 Import into DLP type photopolymer 3D printing equipment.

[0049] (2) Synthesized by wet chemical method using calcium chloride, magnesium chloride and sodium carbonate as raw materials. The powder (average particle size 1 μm) was prepared as follows: Under magnetic stirring, 100 mL of calcium chloride solution (0.01 mol / L) and 100 mL of magnesium chloride solution (0.99 mol / L) were added to 100 mL of sodium carbonate solution (1.0 mol / L). After reacting for 2 hours, the resulting white precipitate was centrifuged and then vacuum dried at 30 °C to obtain the final product. Powder. A photosensitive resin premix was prepared, using epoxy acrylate as the prepolymer, benzoyl peroxide as the initiator, 2-phenoxyethyl acrylate as the diluent, and KOS110 as the dispersant. The powder and resin premix were uniformly mixed and ball-milled for 4 hours to obtain a homogeneous mixture. Photosensitive ceramic slurry (60% solid content). The photosensitive ceramic slurry is placed in the slurry tank of an SLA-type photopolymerization 3D printing equipment. The porous structure 3D model established in step (1) is imported into the SLA-type photopolymerization 3D printing equipment. A scaffold green body with a porous structure resembling a sea urchin skeleton is prepared using the photopolymerization 3D printing process.

[0050] (3) The porous scaffold green body was placed in a muffle furnace and degreased at 550°C for 24 hours to obtain a porous scaffold blank. Then, the porous scaffold blank was sintered at 1000°C under a carbon dioxide atmosphere with a partial pressure of 0.1 MPa for 6 hours to obtain a biomimetic ceramic bone repair scaffold material.

[0051] The resulting biomimetic ceramic bone repair scaffold mimics the porous structure of a sea urchin. Figure 5 The macropore size was measured to be 500 μm using a mercury porosimeter, the porosity was measured to be 50% using the Archimedes displacement method, and the compressive strength was measured to be 30.0 MPa using a universal testing machine. Example

[0052] (1) High-resolution micro-CT scans were used to obtain raw DICOM data from sea urchin skeletons and preprocess the data. After importing the raw data into Mimics software, isotropic voxel resampling, window width and level adjustments were performed, and motion artifacts and noise were removed. Subsequently, the porous structure of the echinoderm skeleton was precisely segmented from the grayscale images, and a high-quality STL format 3D mesh model was exported. Topology repair, surface smoothing, and mesh quality optimization were performed on the model. Boolean operations and mesh simplification were used to further process the model. The processed 3D model was then imported into MeshLab for mesh optimization and refinement. Next, Abaqus finite element analysis software was used to apply realistic loading conditions to the porous structure to analyze its stress distribution and deformation behavior. Based on the finite element analysis results, the pore size, wall thickness, and distribution of the porous structure were further adjusted in MeshLab using a genetic algorithm or topology optimization method to reduce stress concentration. Finally, the optimized 3D model was imported into an SLA-type photopolymerization 3D printing device.

[0053] (2) Synthesized by wet chemical method using calcium chloride, magnesium nitrate and potassium carbonate as raw materials. The powder (average particle size 20 μm) was prepared as follows: Under magnetic stirring, 100 mL of calcium chloride solution (0.99 mol / L) and 100 mL of magnesium nitrate solution (0.01 mol / L) were added to 100 mL of potassium carbonate solution (1.0 mol / L). After reacting for 5 hours, the resulting white precipitate was centrifuged and dried in an oven at 60°C to obtain the final product. Powder. A photosensitive resin premix was prepared using polyurethane acrylate as the prepolymer, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide as the initiator, tetrahydrofuran methyl acrylate as the diluent, and DISPERBYK-109 as the dispersant. The powder and resin premix were uniformly mixed and ball-milled for 6 hours to obtain a homogeneous mixture. Photosensitive ceramic slurry (solid content 30%). The photosensitive ceramic slurry is placed in the slurry tank of the photopolymerization 3D printing equipment. The porous structure 3D model established in step (1) is imported into the SLA-type photopolymerization 3D printing equipment. A scaffold green body with a porous structure resembling a sea urchin skeleton is prepared using the photopolymerization 3D printing process.

[0054] (3) The porous scaffold green body was placed in a muffle furnace and degreased at 600°C for 24 hours to obtain a porous scaffold blank. Then, the porous scaffold blank was sintered at 800°C for 0.5 hours in a carbon dioxide atmosphere with a partial pressure of 2MPa to obtain a biomimetic ceramic bone repair scaffold material.

[0055] The resulting biomimetic ceramic bone repair scaffold mimics the porous structure of a sea urchin. The macropore size was measured to be 800 μm using a mercury porosimeter, the porosity was measured to be 80% using Archimedes' displacement method, and the compressive strength was measured to be 1.0 MPa using a universal testing machine. Example

[0056] (1) High-resolution micro-CT scans were used to obtain raw DICOM data from starfish skeletons and preprocess it. After importing the raw data into Mimics software, isotropic voxel resampling, window width and level adjustment were performed, and motion artifacts and noise were removed. Subsequently, the porous structure of the echinoderm skeleton was accurately segmented from the grayscale image, and a high-quality STL format 3D mesh model was exported. Topology repair, surface smoothing, and mesh quality optimization were performed on the model. The model was further processed through Boolean operations and mesh simplification. The processed 3D model was imported into MeshLab for mesh optimization and refinement. Then, Abaqus finite element analysis software was used to apply realistic loading conditions to the porous structure to analyze its stress distribution and deformation behavior. Based on the finite element analysis results, the pore size, wall thickness, and distribution of the porous structure were further adjusted in MeshLab using genetic algorithms or topology optimization methods to reduce stress concentration. Finally, the optimized 3D model was imported into a DLP-type photopolymerization 3D printing device.

[0057] (2) Synthesized by wet chemical method using calcium nitrate, magnesium chloride and sodium carbonate as raw materials. The powder (average particle size 0.1 μm) was prepared as follows: Under magnetic stirring, 100 mL of calcium nitrate solution (0.5 mol / L) and 100 mL of magnesium chloride solution (0.5 mol / L) were added to 100 mL of sodium carbonate solution (1.0 mol / L). After reacting for 0.5 hours, the resulting white precipitate was centrifuged and then freeze-dried to obtain the final product. Powder. A photosensitive resin premix was prepared, using a prepolymer of polyester acrylate or epoxy resin, an initiator of isopropylthioxanthone, a diluent of neopentyl glycol acrylate, and a dispersant of DISPERBYK-2155. The powder and resin premix were uniformly mixed and ball-milled for 24 hours to obtain a homogeneous mixture. Photosensitive ceramic slurry (80% solid content). The photosensitive ceramic slurry is placed in the slurry tank of the photopolymerization 3D printing equipment. The porous structure 3D model established in step (1) is imported into the DLP type photopolymerization 3D printing equipment. A scaffold green body with a porous structure resembling a starfish skeleton is prepared using the photopolymerization 3D printing process.

[0058] (3) The porous scaffold green body was placed in a muffle furnace and degreased at 500°C for 6 hours to obtain a porous scaffold blank. Then, the porous scaffold blank was sintered at 1200°C under a carbon dioxide atmosphere of 1MPa for 1 hour to obtain a biomimetic ceramic bone repair scaffold material.

[0059] The resulting biomimetic ceramic bone repair scaffold mimics the porous structure of a starfish. The average pore size was measured to be 300 μm using a mercury porosimeter, the porosity was measured to be 30% using Archimedes' displacement method, and the compressive strength was measured to be 150 MPa using a universal testing machine. Example

[0060] (1) High-resolution micro-CT scans were used to obtain raw DICOM data from starfish skeletons and preprocess it. After importing the raw data into Mimics software, isotropic voxel resampling, window width and level adjustment were performed, and motion artifacts and noise were removed. Subsequently, the porous structure of the echinoderm skeleton was accurately segmented from the grayscale image, and a high-quality STL format 3D mesh model was exported. Topology repair, surface smoothing, and mesh quality optimization were performed on the model. The model was further processed through Boolean operations and mesh simplification. The processed 3D model was imported into MeshLab for mesh optimization and refinement. Then, Abaqus finite element analysis software was used to apply realistic loading conditions to the porous structure to analyze its stress distribution and deformation behavior. Based on the finite element analysis results, the pore size, wall thickness, and distribution of the porous structure were further adjusted in MeshLab using genetic algorithms or topology optimization methods to reduce stress concentration. Finally, the optimized 3D model was imported into an SLA-type photopolymerization 3D printing device.

[0061] (2) Synthesized by wet chemical method using calcium nitrate, magnesium chloride and sodium carbonate as raw materials. The powder (average particle size 0.5 μm) was prepared as follows: Under magnetic stirring, 100 mL of calcium nitrate solution (0.3 mol / L) and 100 mL of magnesium chloride solution (0.7 mol / L) were added to 100 mL of sodium carbonate solution (1.0 mol / L). After reacting for 4 hours, the resulting white precipitate was centrifuged and then freeze-dried to obtain the final product. Powder. A photosensitive resin premix was prepared using polyurethane acrylate as the prepolymer, benzoyl peroxide as the initiator, tricyclodecanediethanol diacrylate as the diluent, and KOS110 as the dispersant. The powder and resin premix were uniformly mixed and ball-milled for 4 hours to obtain a homogeneous mixture. Photosensitive ceramic slurry (70% solids content). The photosensitive ceramic slurry is placed in the slurry tank of an SLA-type photopolymerization 3D printing equipment. The porous structure 3D model established in step (1) is imported into the SLA-type photopolymerization 3D printing equipment. A scaffold green body with a porous structure resembling a starfish skeleton is prepared using the photopolymerization 3D printing process.

[0062] (3) The porous scaffold green body was placed in a muffle furnace and degreased at 520°C for 8 hours to obtain a porous scaffold blank. Then, the porous scaffold blank was sintered at 1050°C under a carbon dioxide atmosphere with a partial pressure of 0.5 MPa for 1.5 hours to obtain a biomimetic ceramic bone repair scaffold material.

[0063] The resulting biomimetic ceramic bone repair scaffold mimics the porous structure of a starfish. The macropore size was measured to be 550 μm using a mercury porosimeter, the porosity was measured to be 50% using Archimedes' displacement method, and the compressive strength was measured to be 27.0 MPa using a universal testing machine. Example

[0064] (1) High-resolution micro-CT scans were used to obtain raw DICOM data from starfish skeletons and preprocess it. After importing the raw data into Mimics software, isotropic voxel resampling, window width and level adjustment were performed, and motion artifacts and noise were removed. Subsequently, the porous structure of the echinoderm skeleton was accurately segmented from the grayscale image, and a high-quality STL format 3D mesh model was exported. Topology repair, surface smoothing, and mesh quality optimization were performed on the model. The model was further processed through Boolean operations and mesh simplification. The processed 3D model was imported into MeshLab for mesh optimization and refinement. Then, Abaqus finite element analysis software was used to apply realistic loading conditions to the porous structure to analyze its stress distribution and deformation behavior. Based on the finite element analysis results, the pore size, wall thickness, and distribution of the porous structure were further adjusted in MeshLab using genetic algorithms or topology optimization methods to reduce stress concentration. Finally, the optimized 3D model was imported into an SLA-type photopolymerization 3D printing device.

[0065] (2) Synthesized by wet chemical method using calcium nitrate, magnesium nitrate and sodium carbonate as raw materials. The powder (average particle size 3 μm) was prepared as follows: Under magnetic stirring, 100 mL of calcium nitrate solution (0.3 mol / L) and 100 mL of magnesium nitrate solution (0.7 mol / L) were added to 100 mL of sodium carbonate solution (1.0 mol / L). After reacting for 2 hours, the resulting white precipitate was centrifuged and allowed to air dry naturally to obtain the final product. Powder. A photosensitive resin premix was prepared using polyurethane acrylate as the prepolymer, benzoyl peroxide as the initiator, diethylene glycol diacrylate as the diluent, and KAOCER2020 as the dispersant. The powder and resin premix were uniformly mixed and ball-milled for 4 hours to obtain a homogeneous mixture. Photosensitive ceramic slurry (50% solids content). The photosensitive ceramic slurry is placed in the slurry tank of an SLA-type photopolymerization 3D printing equipment. The porous structure 3D model established in step (1) is imported into the SLA-type photopolymerization 3D printing equipment. A scaffold green body with a porous structure resembling a starfish skeleton is prepared using the photopolymerization 3D printing process.

[0066] (3) The porous scaffold green body was placed in a muffle furnace and degreased at 550°C for 8 hours to obtain a porous scaffold blank. Then, the porous scaffold blank was sintered at 900°C under a carbon dioxide atmosphere with a partial pressure of 0.1 MPa for 3 hours to obtain a biomimetic ceramic bone repair scaffold material.

[0067] The resulting biomimetic ceramic bone repair scaffold mimics the porous structure of a starfish. The macropore size was measured to be 300 μm using a mercury porosimeter, the porosity was measured to be 55% using Archimedes' displacement method, and the compressive strength was measured to be 20.0 MPa using a universal testing machine. Example

[0068] (1) High-resolution micro-CT scans were used to obtain raw DICOM data from sea urchin skeletons and preprocess the data. After importing the raw data into Mimics software, isotropic voxel resampling, window width and level adjustments were performed, and motion artifacts and noise were removed. Subsequently, the porous structure of the echinoderm skeleton was accurately segmented from the grayscale images, and a high-quality STL format 3D mesh model was exported. Topology repair, surface smoothing, and mesh quality optimization were performed on the model. Boolean operations and mesh simplification were used to further process the model. The processed 3D model was then imported into MeshLab for mesh optimization and refinement. Next, Abaqus finite element analysis software was used to apply realistic loading conditions to the porous structure to analyze its stress distribution and deformation behavior. Based on the finite element analysis results, the pore size, wall thickness, and distribution of the porous structure were further adjusted in MeshLab using a genetic algorithm or topology optimization method to reduce stress concentration. Finally, the optimized 3D model was imported into a DLP-type photopolymerization 3D printing device.

[0069] (2) Synthesized by wet chemical method using calcium chloride, magnesium nitrate and potassium carbonate as raw materials. The powder (average particle size 1.5 μm) was prepared as follows: Under magnetic stirring, 100 mL of calcium chloride solution (0.6 mol / L) and 100 mL of magnesium nitrate solution (0.4 mol / L) were added to 100 mL of potassium carbonate solution (1.0 mol / L). After reacting for 1 hour, the resulting white precipitate was centrifuged and vacuum dried at 30 °C to obtain the final product. Powder. A photosensitive resin premix was prepared using epoxy acrylate as the prepolymer, benzoin as the initiator, tetrahydrofuran methyl acrylate as the diluent, and BYK-2155 as the dispersant. The powder and resin premix were uniformly mixed and ball-milled for 4 hours to obtain a homogeneous mixture. Photosensitive ceramic slurry (solid content 45%). The photosensitive ceramic slurry is placed in the slurry tank of a DLP-type photopolymerization 3D printing equipment. The porous structure 3D model established in step (1) is imported into the DLP-type photopolymerization 3D printing equipment. A scaffold green body with a porous structure resembling a sea urchin skeleton is prepared using the photopolymerization 3D printing process.

[0070] (3) The porous scaffold green body was placed in a muffle furnace and degreased at 600°C for 6 hours to obtain a porous scaffold blank. Then, the porous scaffold blank was sintered at 1150°C for 2 hours in a carbon dioxide atmosphere with a partial pressure of 3.0 MPa to obtain a biomimetic ceramic bone repair scaffold material.

[0071] The resulting biomimetic ceramic bone repair scaffold mimics the porous structure of a sea urchin. The macropore size was measured to be 100 μm using a mercury porosimeter, the porosity was measured to be 43% using Archimedes' displacement method, and the compressive strength was measured to be 60.0 MPa using a universal testing machine.

[0072] The present invention and its embodiments have been described above. This description is not restrictive. The accompanying drawings are only one embodiment of the present invention. The actual structure is not limited to this. In short, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the spirit of the present invention, such design should fall within the protection scope of the present invention.

Claims

1. A method for preparing a biomimetic ceramic bone repair scaffold, characterized in that: Includes the following steps: S10: Obtain the raw scan information of the echinoderm skeleton, and preprocess the raw scan information and extract the porous structure to establish the initial three-dimensional model information; S20: Perform stress analysis on the initial three-dimensional model information, and adjust the porous structure parameters according to the analysis results to reduce stress concentration, thereby generating optimized three-dimensional model information; S30: Import the optimized three-dimensional model information into the photopolymerization three-dimensional printing equipment, and use the photopolymerization three-dimensional printing process to print the magnesium calcium carbonate photosensitive ceramic slurry to generate a bracket green body; S40: Degrease the scaffold blank to generate a scaffold preform; S50: The scaffold blank is sintered at high temperature in a carbon dioxide atmosphere to generate a biomimetic ceramic bone repair scaffold material.

2. The method for preparing a biomimetic ceramic bone repair scaffold according to claim 1, characterized in that: Step S10 specifically includes: S101: Micro-CT scans of echinoderms' skeletons were used to obtain raw DICOM data. S102: Perform isotropic voxel resampling, window width and window level adjustment, and noise reduction on the original DICOM data information to generate preprocessed image information; S103: Segment and extract the porous structure from the preprocessed image information, and export the three-dimensional mesh model information; S104: Perform topology repair, surface smoothing and mesh quality optimization on the three-dimensional mesh model information to generate the initial three-dimensional model information.

3. The method for preparing a biomimetic ceramic bone repair scaffold according to claim 1, characterized in that: Step S20 specifically includes: S201: Apply preset loading conditions to the initial three-dimensional model information, perform finite element stress analysis, and generate stress distribution information; S202: Based on the stress distribution information, the pore size, wall thickness and distribution parameters of the porous structure are adjusted by genetic algorithm or topology optimization method to reduce stress concentration and generate the optimized three-dimensional model information.

4. The method for preparing a biomimetic ceramic bone repair scaffold according to claim 1, characterized in that: Step S30 specifically includes: S301: Magnesium calcium carbonate powder is synthesized using a wet chemical method. The chemical formula of the magnesium calcium carbonate is: , where x ranges from 0.01 to 0.99; S302: The magnesium calcium carbonate powder is uniformly mixed with the photosensitive resin premix, and then ball-milled to generate the magnesium calcium carbonate photosensitive ceramic slurry. S303: Place the magnesium calcium carbonate photosensitive ceramic slurry into the slurry tank of the photocuring 3D printing equipment, and import the optimized 3D model information into the photocuring 3D printing equipment; S304: The scaffold blank with a porous structure mimicking the skeleton of an echinoderm was prepared using a photopolymerization 3D printing process.

5. The method for preparing a biomimetic ceramic bone repair scaffold according to claim 4, characterized in that: The wet chemical method in step S301 uses a calcium source, a magnesium source, and a carbonate source for reaction. The calcium source is one of calcium nitrate, calcium chloride, or calcium acetate. The magnesium source is one of magnesium nitrate, magnesium chloride, or magnesium acetate. The carbonate source is one of sodium carbonate or potassium carbonate.

6. The method for preparing a biomimetic ceramic bone repair scaffold according to claim 4, characterized in that: The photosensitive resin premix in step S302 includes a prepolymer, a dispersant, a diluent, and a photoinitiator; the solid content of the magnesium calcium carbonate photosensitive ceramic slurry is 30% to 80%.

7. The method for preparing a biomimetic ceramic bone repair scaffold according to claim 1, characterized in that: The degreasing temperature in step S40 is 400°C to 650°C, and the holding time is 1 to 24 hours.

8. The method for preparing a biomimetic ceramic bone repair scaffold according to claim 1, characterized in that: The partial pressure of the carbon dioxide atmosphere in step S50 is 0.1 to 10 MPa, the temperature of the high-temperature sintering is 800°C to 1100°C, and the holding time is 0.5 to 6 hours.

9. A biomimetic ceramic bone repair scaffold, prepared by the method according to any one of claims 1 to 8, characterized in that: The biomimetic ceramic bone repair scaffold mimics the porous structure and chemical composition of echinoderm bones, with a porosity of 30% to 80%, a pore size of 50 to 800 μm, and a compressive strength of 1.0 to 150 MPa.

10. A biomimetic ceramic bone repair scaffold according to claim 9, characterized in that: The chemical composition of the biomimetic ceramic bone repair scaffold is selected from the chemical composition of starfish or sea urchin skeletons, specifically magnesium calcium carbonate, with the chemical formula: , where x ranges from 0.01 to 0.99.

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