A method for preparing a zinc oxide-aluminum oxide ceramic bone repair scaffold

Abstract

The application relates to the technical field of biomedical materials and discloses a preparation method of a zinc oxide-aluminum oxide ceramic bone repair support; first, aluminum oxide granulated powder and phenolic resin powder are weighed according to proportions, the aluminum oxide granulated powder and the phenolic resin powder are mixed, and 3D printing composite powder is obtained; second, the 3D printing composite powder is prepared into an aluminum oxide ceramic body through a selective laser sintering device; the aluminum oxide ceramic body is dried to obtain a dried ceramic body, the dried ceramic body is subjected to defatting and sintering treatment, and an aluminum oxide preformed body is obtained after cooling; finally, the aluminum oxide preformed body is subjected to vacuum pressure impregnation by using a nano zinc oxide sol, and a dynamic optimization algorithm is introduced to optimize vacuum pressure impregnation parameters, so that the zinc oxide-aluminum oxide ceramic bone repair support is obtained; the zinc oxide-aluminum oxide ceramic bone repair support is obtained through a preparation process and intelligent optimization of process parameters, and the method is objective and accurate.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials, specifically to a method for preparing a zinc oxide-alumina ceramic bone repair scaffold. Background Technology

[0002] Bone defects caused by tumors, infections, trauma, and other factors are common clinical conditions, characterized by their large number, complexity, and significant impact on patients' quality of life. Currently, clinically used bone repair materials mainly include metallic materials, biopolymers, synthetic inorganic materials, and their composites. Among these, alumina bioceramics share similar inorganic components and three-dimensional structures with bone tissue, exhibiting excellent biocompatibility and osteoconductivity. They can integrate well with bone tissue in vivo, thus achieving bone defect repair. Metal oxides such as zinc oxide can endow alumina ceramic bone repair scaffolds with stronger antibacterial capabilities through the dual pathways of releasing metal ions and generating reactive oxygen species, promoting the bone repair process. Alumina bioceramic scaffolds are widely used as bioactive materials, and zinc oxide-alumina bioceramics represent a current research hotspot in the field of bone repair biomaterials.

[0003] The main methods for preparing bone repair scaffolds include foaming, particle leaching, and freeze-drying. Among them, the foaming method involves impregnating ceramic slurry into an organic foam template and then sintering it at high temperature to form a porous structure. The particle leaching method uses a soluble pore-forming agent (such as NaCl particles) mixed with ceramic powder, and after sintering, the pore-forming agent is leached to form pores.

[0004] Traditional methods for preparing bone repair scaffolds make it difficult to precisely design the appearance and internal microstructure of the scaffold, resulting in the inability to achieve blood transport within the scaffold and provide sufficient blood supply to the mid-segment of large bone defects. This often leads to problems such as central bone necrosis and repair failure. Summary of the Invention

[0005] To address the problems in related technologies, this invention provides a method for preparing a zinc oxide-alumina ceramic bone repair scaffold, thereby overcoming the aforementioned technical problems in existing related technologies.

[0006] To solve the aforementioned technical problem, the present invention is achieved through the following technical solution:

[0007] This invention relates to a method for preparing a zinc oxide-alumina ceramic bone repair scaffold, comprising the following steps:

[0008] S1. Preparation of 3D printing powder: Weigh alumina granulated powder and phenolic resin powder according to the ratio, mix the alumina granulated powder and phenolic resin powder to obtain 3D printing composite powder.

[0009] S2. Molding: The 3D printed composite powder is processed by selective laser sintering equipment to prepare an alumina ceramic blank;

[0010] S3. Degreasing and sintering: The alumina ceramic blank is dried to obtain a dried ceramic blank, and the dried ceramic blank is degreased and sintered, and then cooled to obtain an alumina preform.

[0011] S4. Infiltration of the preform: The alumina preform is infiltrated under vacuum pressure using nano zinc oxide sol, and the vacuum pressure infiltration parameters are optimized by introducing the dynamic optimization algorithm to obtain a zinc oxide-alumina ceramic bone repair scaffold.

[0012] Preferably, the step of weighing alumina granulated powder and phenolic resin powder in proportion and mixing the alumina granulated powder and phenolic resin powder includes the following steps:

[0013] Near-spherical alumina powder (20-75 micrometers) and phenolic resin were selected, dried, and alumina granulated powder and phenolic resin powder were obtained. The alumina granulated powder and phenolic resin powder were weighed according to the ratio and mixed to obtain 3D printing composite powder.

[0014] Preferably, alumina granulated powder and phenolic resin powder are weighed in a mass ratio of 0.92:0.08.

[0015] Preferably, the step of passing the 3D printed composite powder through a selective laser sintering device includes the following steps:

[0016] The 3D printed composite powder is passed through a selective laser sintering (SLS) device. The operating parameters of the SLS device are: preheating temperature 55℃, layer thickness 0.18±0.01mm, filling speed 3850±100mm / s, filling power 18W, contour speed 2000±100mm / s, and contour power 10W.

[0017] A gradient filling strategy was adopted, and longitudinal through-holes were set along the long axis of the selective laser sintering equipment, with the pore diameter maintained at 200-500 micrometers. The gradient distribution of the pore spacing was adjusted to obtain an alumina ceramic green body.

[0018] Preferably, the degreasing and sintering treatment of the dried ceramic green body includes the following steps:

[0019] The alumina ceramic blank is dried to obtain a dried ceramic blank, and the dried ceramic blank is degreased to obtain a degreased ceramic blank; then a multi-stage sintering method is used for sintering treatment, and after sintering treatment, the temperature is reduced to 1100℃ at a rate of 5℃±1℃ / min, and cooled to obtain an alumina preform.

[0020] Preferably, the degreasing process is carried out under nitrogen protection by raising the temperature to 300°C at 1°C ± 0.1°C / min, holding for 2 hours, and then raising the temperature to 600°C at 2°C ± 0.2°C / min and holding for 30 minutes to complete the degreasing process.

[0021] Preferably, the sintering process using a multi-stage sintering method includes the following steps:

[0022] During the first stage of sintering, the degreased ceramic green body is held at 600℃ for 30 minutes; during the second stage of sintering, the temperature is increased to 1250℃ at a rate of 8℃±1℃ / min; during the third stage of sintering, the temperature is increased to 1300-1500℃ at a rate of 2.5℃±0.5℃ / min and held for 3 hours to complete the sintering process.

[0023] Preferably, the vacuum pressure impregnation of the alumina preform using nano zinc oxide sol includes the following steps:

[0024] A nano-zinc oxide sol was prepared, and the alumina preform was impregnated under vacuum pressure using the nano-zinc oxide sol. The alumina preform was placed in a vacuum pressure impregnation device and impregnated into the nano-zinc oxide sol. The vacuum pressure impregnation parameters were: vacuum negative pressure 0.06-0.10 MPa, maintained for 1-5 min, and then nitrogen gas was introduced to pressurize to 0.10-0.20 MPa and maintained for 1-5 min.

[0025] Preferably, the step of optimizing the vacuum pressure impregnation parameters using a dynamic optimization algorithm includes the following steps:

[0026] The antibacterial rate, contact angle, and penetration rate of the zinc oxide-alumina ceramic bone repair scaffold were measured, and an objective function was established based on the maximum anti-inflammatory and sterilization performance and superhydrophilic properties.

[0027] The vacuum pressure impregnation parameters include vacuum negative pressure, pressurization pressure, impregnation time, and number of cycles, forming a vacuum pressure impregnation parameter combination; the objective function is used as the fitness function, and the process of finding the optimal fitness function value is regarded as the process of finding the optimal vacuum pressure impregnation parameter combination.

[0028] Define a search space containing oat populations, and treat each oat individual in the oat population as a combination of vacuum pressure infiltration parameters.

[0029] Initialize the oat population and calculate its biological parameters;

[0030] The oat population enters the exploration phase. After the oats fall, they spread. The positions of individual oat individuals in the oat population are updated. The fitness function value corresponding to the individual oat individuals in the oat population is calculated to obtain the current combination of vacuum pressure infiltration parameters.

[0031] The oat population has entered the development stage, and the current combination of vacuum pressure infiltration parameters will be updated based on the simulated propagation process.

[0032] When oat populations do not encounter obstacles during dispersal, the Levy flight and tumbling mechanism is introduced to update the location of individual oat populations based on the biological parameters of the oat populations.

[0033] When oat populations encounter obstacles during propagation, a projectile motion model is introduced to update the positions of individual oat plants.

[0034] The iteration continues until the current iteration count reaches the maximum iteration count, at which point the iteration stops, resulting in the final oat population. Within the final oat population, the oat individuals corresponding to the optimal fitness function value are searched to obtain the optimized vacuum pressure impregnation parameters.

[0035] Preferably, obtaining the zinc oxide-alumina ceramic bone repair scaffold includes the following steps:

[0036] The optimized vacuum pressure impregnation parameters include optimized vacuum negative pressure, optimized pressurization pressure, optimized impregnation time, and optimized number of cycles. The alumina preform is subjected to vacuum pressure impregnation according to the optimized vacuum pressure impregnation parameters to obtain an impregnated repair scaffold. After drying, it is cured at low temperature to obtain a zinc oxide-alumina ceramic bone repair scaffold.

[0037] The present invention has the following beneficial effects:

[0038] 1. This invention achieves optimal material performance balance by selecting alumina powder and phenolic resin in a mass ratio of 92:8, ensuring fluidity while improving uniformity. It uses mechanical mixing and drying treatment to avoid the generation of pores during subsequent high-temperature molding, thus solving the contradiction between strength and formability in 3D printed ceramic materials.

[0039] 2. This invention achieves a gradient distribution of porosity from the center to the edge by dynamically adjusting the filling spacing and laser power gradient of 3D printed composite powder through selective laser sintering equipment, effectively balancing mechanical strength and permeability. It is suitable for bone implants that have dual requirements for load-bearing and nutrient delivery. Furthermore, it introduces a longitudinal through-channel simulation design to simulate the structure of natural bone trabeculae, thereby improving blood transport efficiency.

[0040] 3. This invention reduces the defect rate of alumina ceramic blanks by drying, degreasing and sintering the blanks in stages with gradient heating, which can lead to cracking or internal porosity defects. The entire process uses precise temperature control throughout the degreasing-sintering-cooling process, which takes into account material properties, process efficiency and cost-effectiveness.

[0041] 4. This invention uses a vacuum pressure impregnation method on an alumina preform using nano-zinc oxide sol, and introduces a dynamic optimization algorithm to optimize the vacuum pressure impregnation parameters to prepare a zinc oxide-alumina ceramic bone repair scaffold. This method uses the dynamic optimization algorithm to find the optimal parameters, cleverly balancing global exploration and local development, and its performance is superior to traditional optimization algorithms. The antibacterial rate is used to quantify the anti-inflammatory and sterilization performance, and the contact angle and blood self-transport rate are used to quantify the superhydrophilic performance, allowing more nano-zinc oxide to enter the micropores, resulting in better anti-inflammatory and sterilization effects. At the same time, it drives rapid blood transport, reduces flow resistance, and greatly reduces problems such as bone center necrosis and repair failure, achieving a synergistic improvement in antibacterial properties, hydrophilicity, and permeation efficiency of the zinc oxide-alumina ceramic bone repair scaffold.

[0042] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the embodiments of the invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, the drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This invention provides a schematic flowchart of a method for preparing a zinc oxide-alumina ceramic bone repair scaffold. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0046] To better illustrate the technical solutions of the embodiments of the present invention, such as Figure 1 As shown in the figure, this invention provides a method for preparing a zinc oxide-alumina ceramic bone repair scaffold, specifically including the following:

[0047] S1. Preparation of 3D printing powder: Weigh alumina granulated powder and phenolic resin powder according to the ratio, mix the alumina granulated powder and phenolic resin powder to obtain 3D printing composite powder.

[0048] S1 includes the following steps:

[0049] S11. Select 20-75 micron near-spherical alumina powder and phenolic resin, dry them at 150℃ for 4 hours to obtain alumina granulated powder and phenolic resin powder. Then weigh the alumina granulated powder and phenolic resin powder according to a mass ratio of 0.92:0.08, mix the alumina granulated powder and phenolic resin powder by mechanical mixing, and keep for 12 hours to obtain 3D printing composite powder.

[0050] In this embodiment, alumina powder and phenolic resin powder are selected and mixed mechanically to obtain a 3D printing composite powder. The use of near-spherical powder ensures flowability while improving uniformity. Drying treatment prevents the formation of pores during subsequent high-temperature molding. A 92:8 mass ratio achieves optimal material performance balance, resolving the contradiction between strength and formability in 3D printed ceramic materials. Specifically, for example, near-spherical alumina powder (Al2O3 content ≥99.5%) with a particle size of 50μm and phenolic resin are placed in a vacuum drying oven and dried at 150℃ for 4 hours. 92kg of alumina granulated powder and 8kg of phenolic resin powder (pyrolytic carbon residue rate 45%) are accurately weighed and loaded into a three-dimensional mixer. The equipment speed is set to 25rpm, and mechanical mixing is performed for 12 hours under nitrogen protection to obtain a uniform composite powder with a flowability index <35°.

[0051] S2. Molding: The 3D printed composite powder is processed by selective laser sintering equipment to prepare an alumina ceramic blank;

[0052] S2 includes the following steps:

[0053] S21. The 3D printed composite powder is passed through a selective laser sintering device. The operating parameters of the selective laser sintering device are: preheating temperature 55℃, layer thickness 0.18±0.01mm, filling speed 3850±100mm / s, filling power 18W, contour speed 2000±100mm / s, and contour power 10W.

[0054] S22. Using a gradient filling strategy, longitudinal through-holes are set along the long axis of the selective laser sintering equipment, keeping the pore diameter at 200-500 micrometers, and adjusting the gradient distribution of the pore spacing to obtain an alumina ceramic blank.

[0055] In this embodiment, 3D printed composite powder is used to prepare an alumina ceramic preform through selective laser sintering. This process achieves a gradient distribution of porosity from the center to the edge by dynamically adjusting the filling spacing and laser power gradient. Specifically, for example, the filling parameters are: speed 3850 mm / s, laser power 18 W; the contour parameters are: speed 2000 mm / s, laser power 10 W. A gradient filling strategy is used for 3D forming: a longitudinally interconnected pore network is designed along the long axis of the bone, with the pore diameter controlled within the range of 200-500 μm. The gradient distribution of pore spacing (0.3 mm spacing in the central region) is achieved by dynamically adjusting the laser scanning path. The spacing between layers (0.7mm in the outer area) and the interlayer rotation angle are set to 67° to avoid anisotropic defects. For alumina ceramic green body samples, the porosity was determined to be 38±2% using the helium gravity method, and the proportion of through-holes was >85% by micro-CT analysis (effectively balancing mechanical strength and permeability). The axial compressive strength was >120MPa according to ISO13314 standard (high mechanical properties), and the surface roughness was <15μm using a white light interferometer (improved molding efficiency). The entire process is suitable for the dual requirements of bone implants for load-bearing and nutrient delivery, and the longitudinal through-hole simulation design is introduced to simulate the natural bone trabecular structure, improving blood transport efficiency.

[0056] S3. Degreasing and sintering: The alumina ceramic blank is dried to obtain a dried ceramic blank, and the dried ceramic blank is degreased and sintered, and then cooled to obtain an alumina preform.

[0057] S3 includes the following steps:

[0058] S31. The alumina ceramic green body is dried to obtain a dried ceramic green body. The dried ceramic green body is then degreased by heating to 300℃ at a rate of 1℃±0.1℃ / min under nitrogen protection, holding for 2 hours, and then heating to 600℃ at a rate of 2℃±0.2℃ / min, holding for 30 minutes to complete the degreasing process and obtain a degreased ceramic green body. A multi-stage sintering method is then used for sintering, with the specific steps as follows:

[0059] S311. During the first stage of sintering, the degreased ceramic green body is held at 600℃ for 30 minutes; during the second stage of sintering, the temperature is increased to 1250℃ at a rate of 8℃±1℃ / min; during the third stage of sintering, the temperature is increased to the sintering temperature of 1300-1500℃ at a rate of 2.5℃ / min and held for 3 hours to complete the sintering process.

[0060] S32. After sintering, the temperature is lowered to 1100℃ at a rate of 5℃±1℃ / min, and cooled to obtain an alumina preform.

[0061] In this embodiment, the alumina ceramic green body is dried, then degreased and sintered, and cooled to obtain an alumina preform. This method employs a staged gradient heating process, reducing the green body's defect rate by minimizing cracking or internal porosity defects. The entire process utilizes precise temperature control throughout the degreasing-sintering-cooling cycle, balancing material properties, process efficiency, and cost-effectiveness. Specifically, for example, the dried alumina ceramic green body is placed in a nitrogen protective atmosphere and subjected to gradient heating degreasing to obtain a degreased ceramic green body. A multi-stage sintering process is employed: the first stage ( Pre-sintering: The degreased ceramic green body is held at 600℃ for 30 minutes; Second stage (transition sintering): The temperature is increased from 600℃ to 1250℃ at a heating rate of 8℃±1℃ / min; Third stage (final sintering): The temperature is increased from 1250℃ to the target temperature (a specific value is selected in the range of 1300-1500℃) at a heating rate of 2.5℃±0.5℃ / min, and held at this temperature for 3 hours; After sintering, the temperature is programmed to decrease to 1100℃ at a rate of 5℃ / min, and then cooled to room temperature in the furnace to finally obtain a densified alumina preform;

[0062] S4. Infiltration of the preform: The alumina preform is infiltrated under vacuum pressure using nano zinc oxide sol, and the vacuum pressure infiltration parameters are optimized by introducing the dynamic optimization algorithm to obtain a zinc oxide-alumina ceramic bone repair scaffold.

[0063] S4 includes the following steps:

[0064] S41. Using zinc nitrate as a precursor and ethanol as a solvent, the pH was adjusted to 9-10 with ammonia water, and the mixture was stirred in a water bath at 60°C for 4 hours to prepare nano zinc oxide sol.

[0065] S42. Vacuum pressure impregnation of the alumina preform is performed using nano zinc oxide sol. The alumina preform is placed in a vacuum pressure impregnation device and impregnated into the nano zinc oxide sol. The vacuum pressure impregnation parameters are: vacuum negative pressure 0.06-0.10 MPa, maintained for 1-5 min, and then nitrogen gas is introduced to pressurize to 0.10-0.20 MPa and maintained for 1-5 min.

[0066] S43. The vacuum pressure impregnation parameters include vacuum negative pressure, pressurization pressure, impregnation time, and number of cycles, forming a vacuum pressure impregnation parameter combination. The dynamic optimization algorithm is used to optimize the vacuum pressure impregnation parameters to obtain the optimized vacuum pressure impregnation parameters. The specific steps are as follows:

[0067] S431. Measure the antibacterial rate, contact angle, and penetration rate of the zinc oxide-alumina ceramic bone repair scaffold. Based on the maximum anti-inflammatory and sterilization performance and superhydrophilic properties, establish the following objective function:

[0068]

[0069] Where F represents the objective function, α1 represents the antibacterial rate of the zinc oxide-alumina ceramic bone repair scaffold, α2 represents the contact angle of the zinc oxide-alumina ceramic bone repair scaffold, α3 represents the permeation rate of the zinc oxide-alumina ceramic bone repair scaffold, and ω1, ω2 and ω3 represent weighting coefficients, ensuring that the sum of the weighting coefficients is 1.

[0070] S432. The objective function is used as the fitness function, and the process of finding the optimal fitness function value is regarded as the process of finding the optimal combination of vacuum pressure impregnation parameters.

[0071] Define a search space containing oat populations. Set the number of oat populations as p and the dimension of the oat populations as q. Treat each oat individual in the oat population as a combination of vacuum pressure infiltration parameters.

[0072] Initialize the oat population, let d represent a random number in the interval [0, 1], the current iteration number be t, and the maximum iteration number be T. Then calculate the biological parameters of the oat population, including seed quality. Main awn length Eccentric rotation coefficient Explore and develop smoothing coefficient

[0073] S433. The oat population enters the exploration phase. After the oats fall, they spread. The upper bound of the search space is set to l, and d1 represents a random number in the interval [0, q]. The OR operation is used to update the oat position coefficient. The oat population is updated, and the position of the e-th oat individual at the t-th iteration is set to C. e (t), the average position of the oat population at the t-th iteration is The optimal location of the oat population at the t-th iteration is C. best (t), when the remainder of e and p / 10 is 0, the position of the e-th oat individual in the (t+1)-th iteration. When the remainders of e and p / 10 are both 1, then C e (t+1)=C best (t)+β, otherwise C e (t+1)=C e (t)+β; At this point, calculate the fitness function value corresponding to the oat individual in the oat population to obtain the current combination of vacuum pressure infiltration parameters;

[0074] S434. The oat population enters the development stage. The propagation process is simulated, and the current vacuum pressure infiltration parameter combination is updated. The oat population propagation includes both scenarios with and without obstacles. In the scenario without obstacles, the Levy flight and tumbling mechanisms are introduced to update the individual oat positions, and the torsion coefficient is... Define a torsion matrix A, where the elements are random numbers in the interval [-χ, χ], and the eccentric rotation coefficient is defined. Let Levy's flight coefficient be Levy(q), then we get

[0075] When encountering obstacles, a projectile motion model is introduced to update the position of the e-th oat individual at the t-th iteration. At this point, all stages are completed, and the next generation of oat population is generated. The iteration continues until the current iteration count reaches the maximum iteration count, at which point the iteration stops, and the final oat population is obtained. In the final oat population, the oat individual corresponding to the optimal fitness function value is searched to obtain the optimized vacuum pressure impregnation parameters.

[0076] S44. The optimized vacuum pressure impregnation parameters include optimized vacuum negative pressure, optimized pressurization pressure, optimized impregnation time, and optimized number of cycles. The alumina preform is subjected to vacuum pressure impregnation according to the optimized vacuum pressure impregnation parameters to obtain an impregnated repair scaffold. After drying, it is cured at low temperature to obtain a zinc oxide-alumina ceramic bone repair scaffold.

[0077] In this embodiment, a zinc oxide nano-sol is used to impregnate an alumina preform under vacuum pressure, and the dynamic optimization algorithm is introduced to optimize the vacuum pressure impregnation parameters to obtain optimized parameters for preparing a zinc oxide-alumina ceramic bone repair scaffold. This method uses the dynamic optimization algorithm to find the optimal parameters, cleverly balancing global exploration (avoiding local optima) and local development (rapid convergence) by simulating the "roll-bounce" propagation mechanism of oat seeds, resulting in superior performance compared to traditional optimization algorithms. Furthermore, the antibacterial rate is used to quantify anti-inflammatory and sterilization performance, while the contact angle (less than 10° indicates superhydrophilicity) and blood self-transport rate are used to quantify superhydrophilicity, allowing more zinc oxide nano-sol to enter the micropores, resulting in better anti-inflammatory and sterilization effects, while simultaneously driving... Rapid blood transport reduces flow resistance, significantly minimizing issues like bone necrosis and repair failure. This achieves a synergistic improvement in the antibacterial properties, hydrophilicity, and permeability of the zinc oxide-alumina ceramic bone repair scaffold. Specifically, for example, the precursor is zinc nitrate (0.1 mol / L), and the solvent is anhydrous ethanol, mixed at a volume ratio of 1:3. Ammonia is then added dropwise to adjust the pH to 9.5, and the mixture is stirred in a 60°C water bath for 4 hours to obtain a uniform nano-zinc oxide sol. The antibacterial rate is guaranteed to be ≥90%, the contact angle ≤10°, and the permeability rate ≥8 μL / min. In the implementation examples, regression analysis of past case data was used to establish the relationship between clinical outcomes (such as infection rate and healing time) and performance indicators. By reverse derivation of the optimal weights, we obtain the following clinical scenarios: Scenario A (high risk of infection): priority is given to antibacterial activity, with weight allocation of antibacterial rate (50%), hydrophilicity (30%), and penetration rate (20%), i.e., weight coefficients ω1, ω2, and ω3 are 0.5, 0.3, and 0.2, respectively; Scenario B (rapid healing requirement): priority is given to hydrophilicity and blood penetration, with weight allocation of antibacterial rate (30%), hydrophilicity (40%), and penetration rate (30%), i.e., weight coefficients ω1, ω2, and ω3 are 0.3, 0.4, and 0.3, respectively; Scenario C (balanced performance): default weight allocation of antibacterial rate (40%), hydrophilicity (35%), and penetration rate (25%), i.e., weight coefficients ω1, ω2, and ω3 are 0. 4. 0.35 and 0.25; for example, set the weight coefficients to 0.5, 0.3 and 0.2 respectively according to the priority of antibacterial treatment; for example, set the oat population size to 50, the dimension to 4 (corresponding to 4 vacuum pressure infiltration parameters), the maximum number of iterations to 100, and each parameter to be randomly generated within the range; in the first 20% of iterations, the population updates the parameter combination through the average position and the optimal position, introduces Levy flight to adjust the parameters, avoids local optima, and when encountering obstacles, introduces the projectile motion model to regenerate the parameters until the maximum number of iterations is reached to obtain the optimal parameter combination: vacuum negative pressure: 0.095MPa (held for 2min), pressurization pressure: 0.18MPa (held for 2min), number of cycles: 3.

[0078] The following detailed explanation is provided with reference to specific embodiments:

[0079] Example 1:

[0080] S1. Preparation of 3D printing powder: Weigh alumina granulated powder and phenolic resin powder according to the ratio, mix the alumina granulated powder and phenolic resin powder to obtain 3D printing composite powder.

[0081] Specifically, S1 includes the following steps:

[0082] S11. Take near-spherical alumina powder (Al2O3 content ≥99.5%) with a particle size of 50μm and phenolic resin, place them in a vacuum drying oven and dry them at 150℃ for 4 hours. Accurately weigh 92kg of alumina granulated powder and 8kg of phenolic resin powder (pyrolysis carbon residue rate 45%), and load them together into a three-dimensional mixer. Set the equipment speed to 25rpm and mechanically mix for 12 hours under nitrogen protection to obtain a uniform composite powder with a flowability index <35°.

[0083] S2. Molding: The 3D printed composite powder is processed by selective laser sintering equipment to prepare an alumina ceramic blank;

[0084] Specifically, S2 includes the following steps:

[0085] S21. The 3D printed composite powder is passed through a selective laser sintering device. The operating parameters of the selective laser sintering device are: preheating temperature 55℃, layer thickness 0.18±0.01mm, filling speed 3850±100mm / s, filling power 18W, contour speed 2000±100mm / s, and contour power 10W.

[0086] S22. Using a gradient filling strategy, longitudinal through-holes are set along the long axis of the selective laser sintering equipment, keeping the pore diameter at 200-500 micrometers, and adjusting the gradient distribution of the pore spacing to obtain an alumina ceramic blank.

[0087] Specifically, the filling parameters were: speed 3850 mm / s, laser power 18 W; the contour parameters were: speed 2000 mm / s, laser power 10 W. A gradient filling strategy was used for 3D molding: a longitudinal through-hole network was designed along the long axis of the bone, with the hole diameter controlled within the range of 200-500 μm. The gradient distribution of the hole spacing was achieved by dynamically adjusting the laser scanning path (0.3 mm spacing in the central area and 0.7 mm spacing in the outer area), and the interlayer rotation angle was set to 67°. For the alumina ceramic green body sample, the porosity was determined to be 38±2% using the helium gravity method, and the proportion of through-holes was >85% according to micro-CT analysis. The axial compressive strength was >120 MPa according to ISO13314 standard, and the surface roughness was <15 μm measured using a white light interferometer.

[0088] S3. Degreasing and sintering: The alumina ceramic blank is dried to obtain a dried ceramic blank, and the dried ceramic blank is degreased and sintered, and then cooled to obtain an alumina preform.

[0089] Specifically, S3 includes the following steps:

[0090] S31. The alumina ceramic green body is dried to obtain a dried ceramic green body. The dried ceramic green body is then degreased by heating to 300℃ at a rate of 1℃±0.1℃ / min under nitrogen protection, holding for 2 hours, and then heating to 600℃ at a rate of 2℃±0.2℃ / min, holding for 30 minutes to complete the degreasing process and obtain a degreased ceramic green body. A multi-stage sintering method is then used for sintering, with the specific steps as follows:

[0091] S311. During the first stage of sintering, the degreased ceramic green body is held at 600℃ for 30 minutes; during the second stage of sintering, the temperature is increased to 1250℃ at a rate of 8℃±1℃ / min; during the third stage of sintering, the temperature is increased to the sintering temperature of 1300-1500℃ at a rate of 2.5℃ / min and held for 3 hours to complete the sintering process.

[0092] S32. After sintering, the temperature is lowered to 1100℃ at a rate of 5℃±1℃ / min, and cooled to obtain an alumina preform.

[0093] S4. Infiltration of the preform: The alumina preform is infiltrated under vacuum pressure using nano zinc oxide sol, and the vacuum pressure infiltration parameters are optimized by introducing the dynamic optimization algorithm to obtain a zinc oxide-alumina ceramic bone repair scaffold.

[0094] Specifically, S4 includes the following steps:

[0095] S41. Using zinc nitrate as a precursor and ethanol as a solvent, the pH was adjusted to 9-10 with ammonia water, and the mixture was stirred in a water bath at 60°C for 4 hours to prepare nano zinc oxide sol.

[0096] S42. Vacuum pressure impregnation of the alumina preform is performed using nano zinc oxide sol. The alumina preform is placed in a vacuum pressure impregnation device and impregnated into the nano zinc oxide sol. The vacuum pressure impregnation parameters are: vacuum negative pressure 0.06-0.10 MPa, maintained for 1-5 min, and then nitrogen gas is introduced to pressurize to 0.10-0.20 MPa and maintained for 1-5 min.

[0097] S43. The vacuum pressure impregnation parameters include vacuum negative pressure, pressurization pressure, impregnation time, and number of cycles, forming a vacuum pressure impregnation parameter combination. The dynamic optimization algorithm is used to optimize the vacuum pressure impregnation parameters to obtain the optimized vacuum pressure impregnation parameters. The specific steps are as follows:

[0098] S431. Measure the antibacterial rate, contact angle, and penetration rate of the zinc oxide-alumina ceramic bone repair scaffold. Based on the maximum anti-inflammatory and sterilization performance and superhydrophilic properties, establish the following objective function:

[0099]

[0100] Where F represents the objective function, α1 represents the antibacterial rate of the zinc oxide-alumina ceramic bone repair scaffold, α2 represents the contact angle of the zinc oxide-alumina ceramic bone repair scaffold, α3 represents the permeation rate of the zinc oxide-alumina ceramic bone repair scaffold, and ω1, ω2 and ω3 represent weighting coefficients.

[0101] S432. The objective function is used as the fitness function, and the process of finding the optimal fitness function value is regarded as the process of finding the optimal combination of vacuum pressure impregnation parameters.

[0102] Define a search space containing oat populations. Set the number of oat populations as p and the dimension of the oat populations as q. Treat each oat individual in the oat population as a combination of vacuum pressure infiltration parameters.

[0103] Initialize the oat population, let d represent a random number in the interval [0, 1], the current iteration number be t, and the maximum iteration number be T. Then calculate the biological parameters of the oat population, including seed quality. Main awn length Eccentric rotation coefficient Explore and develop smoothing coefficient

[0104] S433. The oat population enters the exploration phase. After the oats fall, they spread. The upper bound of the search space is set to l, and d1 represents a random number in the interval [0, q]. The OR operation is used to update the oat position coefficient. The oat population is updated, and the position of the e-th oat individual at the t-th iteration is set to C. e (t), the average position of the oat population at the t-th iteration is The optimal location of the oat population at the t-th iteration is C. best (t), when the remainder of e and p / 10 is 0, the position of the e-th oat individual in the (t+1)-th iteration. When the remainders of e and p / 10 are both 1, then C e(t+1)=C best (t)+β, otherwise C e (t+1)=C e (t)+β; At this point, calculate the fitness function value corresponding to the oat individual in the oat population to obtain the current combination of vacuum pressure infiltration parameters;

[0105] S434. The oat population enters the development stage. The propagation process is simulated, and the current vacuum pressure infiltration parameter combination is updated. The oat population propagation includes both scenarios with and without obstacles. In the scenario without obstacles, the Levy flight and tumbling mechanisms are introduced to update the individual oat positions, and the torsion coefficient is... Define a torsion matrix A, where the elements are random numbers in the interval [-χ, χ], and the eccentric rotation coefficient is defined. Let Levy's flight coefficient be Levy(q), then we get

[0106] When encountering obstacles, a projectile motion model is introduced to update the position of the e-th oat individual at the t-th iteration. At this point, all stages are completed, and the next generation of oat population is generated. The iteration continues until the current iteration count reaches the maximum iteration count, at which point the iteration stops, and the final oat population is obtained. In the final oat population, the oat individual corresponding to the optimal fitness function value is searched to obtain the optimized vacuum pressure impregnation parameters.

[0107] S44. The optimized vacuum pressure impregnation parameters include optimized vacuum negative pressure, optimized pressurization pressure, optimized impregnation time, and optimized number of cycles. The alumina preform is subjected to vacuum pressure impregnation according to the optimized vacuum pressure impregnation parameters to obtain an impregnated repair scaffold. After drying, it is cured at low temperature to obtain a zinc oxide-alumina ceramic bone repair scaffold.

[0108] Specifically, the precursor, zinc nitrate (0.1 mol / L), and solvent, anhydrous ethanol, were mixed at a volume ratio of 1:3. Ammonia was then added dropwise to adjust the pH to 9.5. The mixture was stirred in a 60°C water bath for 4 hours to obtain a uniform nano-zinc oxide sol. The target antibacterial rate was ensured to be ≥90%, the contact angle ≤10° (less than 10° is considered superhydrophilic), and the penetration rate ≥8 μL / min. Based on clinical scenario A (high risk of infection), priority antibacterial settings were implemented, with weighting coefficients ω1, ω2, and ω3 of 0.5, 0.3, and 0.2, respectively. For example, the oat population was set to 50, and the dimension was... 4 (corresponding to 4 vacuum pressure infiltration parameters), maximum number of iterations 100, each parameter is randomly generated within the range; in the first 20% of iterations, the population updates the parameter combination through the average position and the optimal position, introduces Levy flight to adjust the parameters to avoid local optima, when encountering obstacles, the projectile motion model is introduced to regenerate the parameters until the maximum number of iterations is reached to obtain the optimal parameter combination: vacuum negative pressure: 0.095MPa (held for 2min), pressurization pressure: 0.18MPa (held for 2min), number of cycles: 3 times, to obtain the zinc oxide-alumina ceramic bone repair scaffold.

[0109] Example 2:

[0110] Based on Example 1, but unlike Example 1, the vacuum negative pressure and pressurization pressure were fixed, and the infiltration time and number of cycles were optimized. Specifically, the vacuum negative pressure was fixed at 0.06 MPa, the pressurization pressure was fixed at 0.10 MPa, the initial infiltration time was set to 2 minutes, and the initial number of cycles was set to 5. The oat population size was set to 50, the dimension was 2 (corresponding to 2 vacuum pressure infiltration parameters), the maximum number of iterations was 100, and each parameter was randomly generated within the range. In the first 20% of iterations, the population updated the parameter combination through the average position and the optimal position, and the Levy flight was introduced to adjust the parameters to avoid local optima. When encountering obstacles, the projectile motion model was introduced to regenerate the parameters until the maximum number of iterations was reached to obtain the optimal parameter combination: the infiltration time was 5 minutes, the number of cycles was 8, and a zinc oxide-alumina ceramic bone repair scaffold was obtained.

[0111] Example 3:

[0112] Based on Example 1, but unlike Example 1, the infiltration time was fixed, and the vacuum negative pressure, pressurization pressure, and number of cycles were optimized. Specifically, the infiltration time was fixed at 1 minute, the initial number of cycles was set to 5, the initial vacuum negative pressure was 0.06 MPa, and the initial pressurization pressure was 0.10 MPa. The oat population size was set to 50, the dimension to be 3 (corresponding to 3 vacuum pressure infiltration parameters), the maximum number of iterations was 100, and each parameter was randomly generated within the range. In the first 20% of iterations, the population updated the parameter combination through the average position and the optimal position, and the Levy flight was introduced to adjust the parameters to avoid local optima. When encountering obstacles, the projectile motion model was introduced to regenerate the parameters until the maximum number of iterations was reached to obtain the optimal parameter combination: the number of cycles was 8, the vacuum negative pressure was 0.10 MPa, and the pressurization pressure was 0.20 MPa, resulting in a zinc oxide-alumina ceramic bone repair scaffold.

[0113] Example 4:

[0114] Based on Example 1, but unlike Example 1, the number of cycles was fixed, and the vacuum negative pressure, pressurization pressure, and infiltration time were optimized. Specifically, the number of cycles was fixed at 5, the initial infiltration time was set to 2 minutes, the initial vacuum negative pressure was 0.06 MPa, and the initial pressurization pressure was 0.10 MPa. The oat population size was set to 50, the dimension to be 3 (corresponding to 3 vacuum pressure infiltration parameters), the maximum number of iterations was 100, and each parameter was randomly generated within the range. In the first 20% of iterations, the population updated the parameter combination through the average position and the optimal position, and the Levy flight was introduced to adjust the parameters to avoid local optima. When encountering obstacles, the projectile motion model was introduced to regenerate the parameters until the maximum number of iterations was reached to obtain the optimal parameter combination: an infiltration time of 5 minutes, a vacuum negative pressure of 0.095 MPa, and a pressurization pressure of 0.18 MPa, resulting in a zinc oxide-alumina ceramic bone repair scaffold.

[0115] Example 5:

[0116] Based on Example 1, but differing from Example 1, a particle swarm optimization algorithm was used to optimize the number of cycles, vacuum pressure, pressurization pressure, and infiltration time. Specifically, the initial number of cycles was set to 5, the initial infiltration time to 2 minutes, the initial vacuum pressure to 0.06 MPa, and the initial pressurization pressure to 0.10 MPa. The number of particles was set to 50, the dimension to 4 (corresponding to 4 vacuum pressure infiltration parameters), and the maximum number of iterations to 100. Each parameter was randomly generated within the range. The particle velocity was updated, and linear decreasing inertia was used to accelerate convergence. Then, the particle position was updated, and the variable boundary was treated with reflective boundary to avoid invalid solutions. The antibacterial rate, contact angle, and permeation rate were recorded until the maximum number of iterations was reached to obtain the optimal parameter combination: 4 cycles, 5 minutes of infiltration time, 0.09 MPa of vacuum pressure, and 0.18 MPa of pressurization pressure, resulting in a zinc oxide-alumina ceramic bone repair scaffold.

[0117] Example 6:

[0118] Based on Example 1, but differing from Example 1, Scenario B (rapid healing requirement) is selected: prioritizing hydrophilicity and blood penetration, with the following weighting: antibacterial rate (30%), hydrophilicity (40%), and penetration rate (30%), i.e., weighting coefficients ω1, ω2, and ω3 are 0.3, 0.4, and 0.3, respectively; the initial number of cycles is set to 5, the initial infiltration time is set to 2 minutes, the initial vacuum negative pressure is 0.06 MPa, and the initial pressurization pressure is 0.10 MPa; the particle count is set to 50, and the dimension is 4 (corresponding to 4 vacuum pressure infiltrations). The parameters were randomly generated within a range, with a maximum iteration count of 100. In the first 20% of iterations, the population updated the parameter combination through the average position and the optimal position. The Levy flight was introduced to adjust the parameters to avoid local optima. When encountering obstacles, the projectile motion model was introduced to regenerate the parameters until the maximum number of iterations was reached to obtain the optimal parameter combination: vacuum negative pressure: 0.08MPa (held for 5 min), pressurization pressure: 0.19MPa (held for 5 min), number of cycles: 5, to obtain the zinc oxide-alumina ceramic bone repair scaffold.

[0119] Example 7:

[0120] Based on Example 1, but differing from Example 1, Scenario C (Balanced Performance) is selected: Default weight allocation: antibacterial rate (40%), hydrophilicity (35%), and permeation rate (25%), i.e., weighting coefficients ω1, ω2, and ω3 are 0.4, 0.35, and 0.25, respectively; the initial number of cycles is set to 5, the initial impregnation time to 2 minutes, the initial vacuum negative pressure to 0.06 MPa, and the initial pressurization pressure to 0.10 MPa; the particle number is set to 50, and the dimension to 4 (corresponding to 4 vacuum pressure impregnation parameters). The maximum number of iterations was 100, and each parameter was randomly generated within the range. In the first 20% of iterations, the population updated the parameter combination through the average position and the optimal position. The Levy flight was introduced to adjust the parameters to avoid local optima. When encountering obstacles, the projectile motion model was introduced to regenerate the parameters until the maximum number of iterations was reached to obtain the optimal parameter combination: vacuum negative pressure: 0.09MPa (held for 5 min), pressurization pressure: 0.20MPa (held for 5 min), number of cycles: 5, to obtain the zinc oxide-alumina ceramic bone repair scaffold.

[0121] Example 8:

[0122] Based on Example 1, but unlike Example 1, the weighting coefficients ω1, ω2, and ω3 were randomly selected as 0.4, 0.4, and 0.2, respectively; the initial number of cycles was set to 5, the initial infiltration time to 2 minutes, the initial vacuum negative pressure to 0.06 MPa, and the initial pressurization pressure to 0.10 MPa; the number of particles was set to 50, the dimension to 4 (corresponding to 4 vacuum pressure infiltration parameters), the maximum number of iterations to 100, and each parameter was randomly generated within the range; in the first 20% of iterations, the population updated the parameter combination through the average position and the optimal position, and the Levy flight was introduced to adjust the parameters to avoid local optima. When encountering obstacles, the projectile motion model was introduced to regenerate the parameters until the maximum number of iterations was reached to obtain the optimal parameter combination: vacuum negative pressure: 0.15 MPa (held for 7 min), pressurization pressure: 0.22 MPa (held for 7 min), number of cycles: 8, resulting in a zinc oxide-alumina ceramic bone repair scaffold.

[0123] In Examples 1-8 above, the measurement methods for antibacterial rate and hydrophilicity all employed rabbit bone experiments. The specific steps of the rabbit bone experiments are as follows:

[0124] The cytotoxicity, anti-inflammatory and antibacterial properties, osteoinductive properties, and blood transport capacity of ZAS (zinc oxide-alumina ceramic bone repair scaffold) were investigated using bone marrow mesenchymal stem cells from rabbit bone marrow blood. The main characterizations included cell morphology, cell activity, and proliferation.

[0125] Materials grouping: Three groups of materials were prepared: blank group (cultured in culture medium, boneless repair scaffold), control group (cultured in traditional ceramic scaffold), and experimental group (cultured in ZAS).

[0126] Blood collection: The rabbit femur was surgically removed, the femoral heads at both ends of the rabbit were cut off, and the bone marrow blood of the rabbit femur was obtained by rinsing.

[0127] Cell inoculation solution: The experimental group directly used ZAS to extract rabbit bone marrow blood. After the rabbit bone marrow blood was fully absorbed, it was incubated in an incubator for 20 minutes (more than 1 hour, then removed and a little culture medium was added every 20 minutes) for 7-21 days.

[0128] The following treatments were performed on the three groups of materials during the cultivation process:

[0129] Days 1, 3, and 7: CCK-8 cell viability assay;

[0130] One day in advance, seed the cells into a 96-well plate, set up 5 replicates, and four time groups of 12, 24, 36 and 48 hours;

[0131] When the cells have covered about 70% of the bottom area of ​​the well, add ZAS according to the set concentration gradient and set up a blank control.

[0132] After 12 / 24 / 36 / 48h, the ZAS of the corresponding time groups were taken out, and 10μl of CCK-8 detection reagent was added to each well.

[0133] The cell viability bar chart was plotted after the data was read using an ELISA reader.

[0134] Precautions: The cell suspension must be thoroughly mixed before inoculation to prevent cell sedimentation and inconsistent cell numbers. The culture medium in the outermost ring of wells is more prone to evaporation; to minimize error, it is recommended to add only culture medium, not cells, to the wells around the perimeter. When adding CCK-8, it is recommended to add it at an angle against the plate wall, not submerged in the culture medium, as this can create air bubbles and interfere with OD values. Before measuring absorbance, ensure that each well is free of air bubbles; otherwise, it will interfere with the measurement and result in abnormal absorbance values. Please measure the absorbance at 450 nm. If a 450 nm filter is unavailable, a 420-480 nm filter can be used. If measuring the absorbance of cultured cells over multiple consecutive days, maintain a consistent CCK-8 incubation time each time to avoid deviations in absorbance values ​​due to different incubation times.

[0135] Day 7: Divide the experimental group into three subgroups;

[0136] The first group of materials was fractured in the middle and fixed using electron microscopy fixative. The materials were then fixed on the sample stage and observed and analyzed by selected area electron diffraction (SEM). Cell morphology was observed, including cell density, cell shape, and cell levitation. Classic images were taken and compared with images from the control group.

[0137] The second group of materials was directly stained (live / deadstaining, 2.5D confocal microscopy imaging) to observe osteocyte growth in the middle of the scaffold. Simultaneously, a control group was directly stained to observe osteocyte growth in the middle for comparison.

[0138] The third group had the largest number of cells. The culture medium was changed to osteogenic medium and the cells were cultured without any other treatment.

[0139] Day 21: Osteogenic differentiation marker test: alkaline phosphatase unstained Elesa test;

[0140] Antibacterial experiment: The blank group, control group and experimental group were cultured in the same way. During the culture process, the sterilization status was observed by live and dead staining. After bacterial culture for 12 hours, 1 day and 3 days, CCK-8 identification was performed to obtain live and dead staining images. The inhibition zone experiment was carried out and the animal implantation surgery was started.

[0141] The experimental rabbits were randomly divided into 3 groups (no treatment group, traditional bone repair scaffold group, and ZAS group);

[0142] Establish a rabbit femoral condyle fracture model;

[0143] Adaptive feeding for 1 week, and fasting / abstaining from drinking for 6 hours before surgery;

[0144] Anesthesia was administered via intravenous injection of 3% pentobarbital (0.5 ml / kg) into the ear.

[0145] After the anesthesia took effect, the experimental rabbits were placed in a supine position on the animal operating table, and their limbs were fixed with bandages.

[0146] Shave and disinfect the lower limbs, with the area centered on the knee joint and 20cm around it, and then cover with a towel as usual.

[0147] With the knee joint flexed, make a 5cm lateral midline incision, dissect layer by layer, and incise the lateral retinaculum.

[0148] Extend your knee and gently push the patella inward to dislocate it, exposing the femoral condyle. Then bend your knee.

[0149] The ipsilateral bone was drilled above the lateral femoral condyle articular surface using a bone drill, and then the ipsilateral cortex and internal cancellous bone were chiseled with a bone chisel, while the contralateral cortex was left intact, creating a cavity-like bone defect with a diameter of 7 mm and a depth of approximately 6 mm (to be measured). The defect was rinsed with sterile saline until no bone fragments or bone marrow remained, and a ZAS of the appropriate length / no treatment / traditional bone repair scaffold was implanted. The same method was used to prepare two bone defect areas in the left femur.

[0150] After rinsing with diluted iodine solution and saline solution, close the wound layer by layer;

[0151] Postoperative intramuscular injection of 1.6 million UI of penicillin;

[0152] Surgery was performed on both legs. Postoperatively, the animal’s activity was not restricted. The animal’s general condition was observed, including its mental state, eating, urination and defecation, and movement of the affected limb. Attention was paid to whether the wound became infected or reopened.

[0153] Micro-CT scan:

[0154] The interface between the scaffold and bone, as well as surrounding bone growth, was examined using high-resolution micro-CT. Four weeks post-surgery, the surgical site specimen was scanned using a micro-CT scanner (pixel size 19 μm, scanning voltage 70 kVp, scanning current 114 μA, integration time 250 ms). The generated engineering files were analyzed using μCT software. The auto-contouring function was used to calculate bone mass within 1 mm around the implant, assess the relative volume of trabecular bone (BV / TV), and perform 3D reconstruction for a more intuitive observation of the implant interface and surrounding bone growth.

[0155] In vivo testing and serum biochemical assays for biosafety:

[0156] Twenty-four weeks post-surgery, serum was collected, and serum creatinine (Cr) and alanine aminotransferase (ALT) were measured using an ELISA kit according to the instructions. Liver and kidney function were assessed, and systemic inflammatory marker C-reactive protein (CRP) was measured to observe for systemic inflammatory response.

[0157] Histological examination of vital organs:

[0158] Twenty-four weeks post-surgery, internal organs (liver, spleen, kidney) and soft tissue around the implant were collected and fixed with 4% paraformaldehyde solution. The liver, spleen, kidney and soft tissue around the implant were fixed with 4% paraformaldehyde, dehydrated, embedded, made into paraffin sections, and stained with hematoxylin and eosin (HE) to observe whether there were obvious changes in organ structure and local inflammatory reactions around the surgery.

[0159] Statistical analysis:

[0160] Statistical analysis was performed using statistical analysis software. Data are expressed as mean ± standard deviation (±s). The t-test was used for comparisons, and P < 0.05 was considered statistically significant.

[0161] Analysis of the conclusions of the example:

[0162] Example 1: Performance indicators measured were as follows: antibacterial rate of 95%, contact angle of 8°, permeation rate of 9.5 μL / min, and fitness function value of 1.24. The antibacterial rate was optimized from the initial 85% to 95%, significantly reducing the risk of postoperative infection. The contact angle was optimized from the initial 15° to 8°, reaching the superhydrophilic standard (less than 10°), enhancing the affinity between the scaffold and body fluids / cells, and promoting bone tissue regeneration. The permeation rate was increased from 7 μL / min to 9.5 μL / min, shortening the infiltration process time and improving the permeation efficiency. The total process time was 20 hours.

[0163] Example 2 showed an antibacterial rate of 78%, a contact angle of 20°, and a penetration rate of 4.5 μL / min. Compared to Example 1, the antibacterial rate of only 78% was lower than 95%, indicating insufficient antibacterial performance and an increased risk of postoperative infection. Furthermore, the contact angle of 20° was greater than 8°, resulting in poor wettability and hydrophilicity, which affected cell adhesion and bone integration. Simultaneously, the penetration rate of only 4.5 μL / min was lower than 9.5 μL / min, requiring 8 cycles to reach the target penetration volume, extending the processing time by 20%.

[0164] Example 3 showed an antibacterial rate of 82%, a contact angle of 18°, and a penetration rate of 5.2 μL / min. Compared to Example 1, the antibacterial rate of only 82% was lower than 95%, indicating insufficient antibacterial performance and an increased risk of postoperative infection. In addition, the contact angle of 18° was greater than 8°, resulting in insufficient sol surface expansion due to the short immersion time and poor hydrophilicity. At the same time, the penetration rate of only 5.2 μL / min was lower than 9.5 μL / min, requiring 8 cycles to reach the target penetration amount, extending the process time by 20%.

[0165] Example 4 showed an antibacterial rate of 85%, a contact angle of 15°, and a penetration rate of 5.2 μL / min. Compared to Example 1, the antibacterial rate of only 85% was lower than 95%, indicating insufficient antibacterial performance and an increased risk of postoperative infection. Furthermore, the contact angle of 15° was greater than 8°, resulting in insufficient sol surface expansion and poor hydrophilicity due to the short immersion time. Simultaneously, the penetration rate of only 5.2 μL / min was lower than 9.5 μL / min, requiring 5 cycles to reach the target penetration amount, extending the process time by 10%.

[0166] Example 5 showed an antibacterial rate of 90%, a contact angle of 10°, and a penetration rate of 9.0 μL / min. Compared to Example 1, the antibacterial rate of 90% is lower than 95%, indicating insufficient antibacterial performance. In addition, the contact angle of 10° is greater than 8°, indicating poor hydrophilicity. At the same time, the penetration rate of 9.0 μL / min is lower than 9.5 μL / min, requiring 4 cycles to reach the target penetration amount, thus extending the process time by 10%.

[0167] Example 6: The measured antibacterial rate was 88%, the contact angle was 8°, and the penetration rate was...

[0168] The antibacterial rate was 9.4 μL / min; compared to Example 1, the antibacterial rate was 88%, which is lower than 95%, increasing the risk of postoperative infection; in addition, the contact angle of 8° reached the superhydrophilic standard, indicating good hydrophilicity; at the same time, the permeation rate of 9.4 μL / min was slightly lower than 9.5 μL / min, requiring 4 cycles to reach the target permeation volume, extending the process time by 10%; at the same time, the fitness function value was 0.99, which is lower than 1.24, indicating good hydrophilicity and blood penetration;

[0169] Example 7: The measured antibacterial rate was 90%, the contact angle was 9°, and the penetration rate was...

[0170] The antibacterial rate was 9.2 μL / min; compared to Example 1, the antibacterial rate was 88%, which is lower than 95%, indicating insufficient antibacterial performance and an increased risk of postoperative infection; in addition, the contact angle was 9°, which is slightly greater than 8°, reaching the superhydrophilic standard; at the same time, the permeation rate was 9.2 μL / min, which is slightly lower than 9.5 μL / min, requiring 4 cycles to reach the target permeation volume, thus extending the process time by 10%; at the same time, the fitness function value was 0.8, which is lower than 1.24, indicating good balance;

[0171] Example 8 showed an antibacterial rate of 88%, a contact angle of 10°, and a penetration rate of 8.1 μL / min. Compared to Example 1, the antibacterial rate of 90% was lower than 95%, indicating insufficient antibacterial performance and an increased risk of postoperative infection. Furthermore, the contact angle of 10° was greater than 8°, failing to meet the superhydrophilic standard. Simultaneously, the penetration rate of 9.1 μL / min was lower than 9.5 μL / min, requiring 4 cycles to reach the target penetration amount, extending the process time by 10%. Additionally, the fitness function value was 0.79, lower than 1.24, indicating insufficient anti-inflammatory and sterilization performance as well as insufficient superhydrophilic performance.

[0172] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0173] The preferred embodiments of the invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A method for preparing a zinc oxide-alumina ceramic bone repair scaffold, characterized in that, include: S1. Preparation of 3D printing powder: Weigh alumina granulated powder and phenolic resin powder according to the ratio, mix the alumina granulated powder and phenolic resin powder to obtain 3D printing composite powder. S2. Molding: The 3D printed composite powder is processed by selective laser sintering equipment to prepare an alumina ceramic blank; S3. Degreasing and sintering: The alumina ceramic blank is dried to obtain a dried ceramic blank, and the dried ceramic blank is degreased and sintered, and then cooled to obtain an alumina preform. S4. Infiltration of the preform: The alumina preform is infiltrated under vacuum pressure using nano zinc oxide sol, and the vacuum pressure infiltration parameters are optimized by introducing the dynamic optimization algorithm to obtain a zinc oxide-alumina ceramic bone repair scaffold.

2. The method for preparing a zinc oxide-alumina ceramic bone repair scaffold according to claim 1, characterized in that, The step of weighing alumina granulated powder and phenolic resin powder according to the specified ratio and mixing the alumina granulated powder and phenolic resin powder includes the following steps: Near-spherical alumina powder (20-75 micrometers) and phenolic resin were selected, dried, and alumina granulated powder and phenolic resin powder were obtained. The alumina granulated powder and phenolic resin powder were weighed according to the ratio and mixed to obtain 3D printing composite powder.

3. The method for preparing a zinc oxide-alumina ceramic bone repair scaffold according to claim 2, characterized in that, Weigh alumina granulated powder and phenolic resin powder according to a mass ratio of 0.92:0.

08.

4. The method for preparing a zinc oxide-alumina ceramic bone repair scaffold according to claim 3, characterized in that, The process of passing the 3D printed composite powder through a selective laser sintering device includes the following steps: The 3D printed composite powder is passed through a selective laser sintering (SLS) device. The operating parameters of the SLS device are: preheating temperature 55℃, layer thickness 0.18±0.01mm, filling speed 3850±100mm / s, filling power 18W, contour speed 2000±100mm / s, and contour power 10W. A gradient filling strategy was adopted, and longitudinal through-holes were set along the long axis of the selective laser sintering equipment, with the pore diameter maintained at 200-500 micrometers. The gradient distribution of the pore spacing was adjusted to obtain an alumina ceramic green body.

5. The method for preparing a zinc oxide-alumina ceramic bone repair scaffold according to claim 4, characterized in that, The process of degreasing and sintering the dried ceramic green body includes the following steps: The alumina ceramic blank is dried to obtain a dried ceramic blank, and the dried ceramic blank is degreased to obtain a degreased ceramic blank; then a multi-stage sintering method is used for sintering treatment, and after sintering treatment, the temperature is reduced to 1100℃ at a rate of 5℃±1℃ / min, and cooled to obtain an alumina preform.

6. The method for preparing a zinc oxide-alumina ceramic bone repair scaffold according to claim 5, characterized in that, The degreasing process was carried out under nitrogen protection by heating to 300℃ at a rate of 1℃±0.1℃ / min and holding for 2 hours, followed by heating to 600℃ at a rate of 2℃±0.2℃ / min and holding for 30 minutes to complete the degreasing process.

7. The method for preparing a zinc oxide-alumina ceramic bone repair scaffold according to claim 6, characterized in that, The subsequent sintering process using a multi-stage sintering method includes the following steps: During the first stage of sintering, the degreased ceramic green body is held at 600℃ for 30 minutes; during the second stage of sintering, the temperature is increased to 1250℃ at a rate of 8℃±1℃ / min; during the third stage of sintering, the temperature is increased to 1300-1500℃ at a rate of 2.5℃±0.5℃ / min and held for 3 hours to complete the sintering process.

8. The method for preparing a zinc oxide-alumina ceramic bone repair scaffold according to claim 7, characterized in that, The vacuum pressure impregnation of the alumina preform using nano zinc oxide sol includes the following steps: A nano-zinc oxide sol was prepared, and the alumina preform was impregnated under vacuum pressure using the nano-zinc oxide sol. The alumina preform was placed in a vacuum pressure impregnation device and impregnated into the nano-zinc oxide sol. The vacuum pressure impregnation parameters were: vacuum negative pressure 0.06-0.10 MPa, maintained for 1-5 min, and then nitrogen gas was introduced to pressurize to 0.10-0.20 MPa and maintained for 1-5 min.

9. The method for preparing a zinc oxide-alumina ceramic bone repair scaffold according to claim 8, characterized in that, The optimization of vacuum pressure impregnation parameters by introducing a dynamic optimization algorithm includes the following steps: The antibacterial rate, contact angle, and penetration rate of the zinc oxide-alumina ceramic bone repair scaffold were measured, and an objective function was established based on the maximum anti-inflammatory and sterilization performance and superhydrophilic properties. The vacuum pressure impregnation parameters include vacuum negative pressure, pressurization pressure, impregnation time, and number of cycles, forming a vacuum pressure impregnation parameter combination; the objective function is used as the fitness function, and the process of finding the optimal fitness function value is regarded as the process of finding the optimal vacuum pressure impregnation parameter combination. Define a search space containing oat populations, and treat each oat individual in the oat population as a combination of vacuum pressure infiltration parameters. Initialize the oat population and calculate its biological parameters; The oat population enters the exploration phase. After the oats fall, they spread. The positions of individual oat individuals in the oat population are updated. The fitness function value corresponding to the individual oat individuals in the oat population is calculated to obtain the current combination of vacuum pressure infiltration parameters. The oat population has entered the development stage, and the current combination of vacuum pressure infiltration parameters will be updated based on the simulated propagation process. When oat populations do not encounter obstacles during dispersal, the Levy flight and tumbling mechanism is introduced to update the location of individual oat populations based on the biological parameters of the oat populations. When oat populations encounter obstacles during propagation, a projectile motion model is introduced to update the positions of individual oat plants. The iteration continues until the current iteration count reaches the maximum iteration count, at which point the iteration stops and the final oat population is obtained. In the final oat population, the oat individuals corresponding to the optimal fitness function value are identified to obtain the optimized vacuum pressure impregnation parameters.

10. The method for preparing a zinc oxide-alumina ceramic bone repair scaffold according to claim 9, characterized in that, The process of obtaining the zinc oxide-alumina ceramic bone repair scaffold includes the following steps: The optimized vacuum pressure impregnation parameters include optimized vacuum negative pressure, optimized pressurization pressure, optimized impregnation time, and optimized number of cycles. The alumina preform is subjected to vacuum pressure impregnation according to the optimized vacuum pressure impregnation parameters to obtain an impregnated repair scaffold. After drying, it is cured at low temperature to obtain a zinc oxide-alumina ceramic bone repair scaffold.

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