A light-curing 3D printed minimal curved surface artificial bone scaffold and its preparation method

Abstract

The present invention discloses a photocuring 3D printed minimal curved surface artificial bone scaffold and a preparation method thereof. A calcium phosphate ceramic / bioglass composite ceramic scaffold is prepared using photocuring 3D printing technology. The photocuring 3D printed minimal curved surface artificial bone scaffold and the preparation method thereof of the present invention construct a structural gradient bionic scaffold through structural hybridization design. Its internal high permeability and external high-strength small pore structure provide efficient material transport channels and strong mechanical support for large bone defects. Combined with the introduction of magnesium ions and molybdenum ions in bioglass, the sustained release of active ions during the implantation process inhibits osteoclast activity and promotes osteogenic differentiation, effectively improving the compatibility problem between the scaffold mechanical properties and osteogenic activity in bone defect repair, and improving the osteogenic capacity of the ceramic scaffold.

Description

Technical Field

[0001] The present invention belongs to the technical field of bone repair materials and additive manufacturing, and specifically relates to a light-cured 3D printed minimum curved surface artificial bone scaffold and a preparation method thereof. Background Art

[0002] Human bone tissue has a complex composition and structure, and can perform a variety of unique functions in the body. However, bone regeneration capacity is limited, and effective treatment of bone defects caused by trauma, infection, bone tumor resection, etc. remains a major clinical need and challenge. Among them, artificial bone transplant scaffolds, as a new bone repair method, have the characteristics of personalized design, simulating the structure and biological function of healthy bone tissue in terms of chemical composition, hierarchical structure and performance. Bioceramics (such as calcium phosphate ceramics, calcium silicate ceramics and bioactive glass, etc.) have inorganic components similar to bones, good biocompatibility, osteoconduction and osteoinduction, and are often used in the selection of materials for artificial bone scaffolds.

[0003] Bone repair scaffolds need to have a highly connected pore network to mimic the original structure of natural bone. This provides sufficient surface area for the interaction between the scaffold and cells and surrounding tissues, promoting biological fixation and material transport. Different scaffold structures have a significant impact on blood vessel growth and bone repair. Traditional ceramic preparation techniques such as gas foaming and impregnation methods make it difficult to control parameters such as pores and size. In recent years, additive manufacturing (AM) technology has greatly promoted the development of bone tissue engineering. Through the optimization of scaffold structure and the regulation of 3D printing process parameters, various bone repair scaffolds with complex and fine structures and functionalization have been manufactured. Stereolithography technology (SLA) is based on photocuring molding with a point light source, and the scaffold has high dimensional accuracy.

[0004] Bone repair scaffolds typically utilize porous structures. While these structures possess excellent mechanical properties, they lack sufficient fluid permeability to mimic the cancellous bone within. A three-period minimum surface, present in nature, is a surface with an average curvature of zero, representing a state of minimum energy. Minimal surface structures are widely found in nature and possess superior mechanical properties and fluid permeability compared to conventional porous structures. While existing minimal surface structures should be widely adopted, their application in artificial bone scaffolds and ensuring their bone repair effectiveness remains a major research area within the industry. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a light-cured 3D printed minimum curved surface artificial bone scaffold and a preparation method thereof, which has good bone repair effect, has bone properties and sufficient mechanical strength.

[0006] The technical solution of the present invention to solve the above technical problems is:

[0007] A method for preparing a light-curved 3D-printed minimal-curved artificial bone scaffold comprises the following steps:

[0008] Modeling parameter acquisition: based on the actual size, shape, and location of the corresponding human bone, the corresponding size, shape, pore size, and porosity of the human bone are determined to obtain modeling parameters;

[0009] Modeling: Using Matlab, Rhino, or Grasshopper software, and utilizing two or more TPMS implicit functions, based on modeling parameters, a three-periodic minimum surface structure model with internal structural hybridization and a surface network model with an external high-strength porous structure are constructed. Sigmod functions are used for radial transition connections, and a bionic model that meets the modeling parameters is obtained by adjusting the pore size, wall thickness, and pores.

[0010] Model fine-tuning: export the bionic model in STL mode, then further modify and design the bionic model in this mode to obtain a printing model, and then perform finite element simulation on the printing model to obtain printing parameters;

[0011] The printing slurry is prepared by mixing 5-25% of bioactive glass powder containing Mg and Mo, 40-53% of calcium phosphate ceramic powder, 5-30% of photosensitive resin, 0.2-5% of photoinitiator, 0.2-5% of light absorber and 2-6% of dispersant in a weight ratio to obtain a mixture, and then ball milling the mixture to obtain a light-curing slurry;

[0012] 3D printing: the photocurable slurry is introduced into the material tank of the SLA printer, and the printing model is input into the SLA printer. The printing parameters are adjusted for printing, and the semi-finished product is obtained after printing;

[0013] Clean and dry the semi-finished product with cleaning liquid to remove residual resin, and then dry it in an environment of 60℃ for 12 hours;

[0014] Degreasing and sintering: Place the dried semi-finished product into a sintering furnace and sinter it using a four-stage degreasing and sintering method. After sintering, cool it to room temperature with the furnace to obtain a light-curing 3D printed minimum curved artificial bone scaffold.

[0015] Specifically, in the printing slurry preparation step, the bioactive glass powder containing Mg and Mo is prepared from sodium carbonate, calcium carbonate, basic magnesium carbonate, diammonium hydrogen phosphate and molybdenum source powder in a molar ratio of (1-10):(1-10):(1-20):(1-15):(0.1-5), and the preparation steps include:

[0016] Mixing, adding CaO, Na2O, P2O3, MgO and MoO3 prepared in molar proportions into ultrapure water in sequence and mixing to obtain a mixed solution;

[0017] Heating: using a heating furnace to heat and boil the mixed liquid until the mixed liquid becomes viscous to obtain a viscous liquid;

[0018] Melt, quickly transfer the viscous liquid to a corundum crucible in a muffle furnace, and gradually heat it until the temperature reaches 900°C to obtain a molten liquid;

[0019] Quenching, quickly placing the melt into deionized water for rapid cooling and quenching, and obtaining bioactive glass containing Mg and Mo after complete cooling;

[0020] Ball milling: placing the bioactive glass containing Mg and Mo into a ball mill and adding ethanol for ball milling at a ball milling speed of 200-350 r / min for 1.5-3 h to obtain a bioactive glass powder containing Mg and Mo with a particle size of micrometers;

[0021] The selected molybdenum source is one of ammonium molybdate tetrahydrate, molybdenum trioxide, ammonium molybdate carbonate, ammonium molybdate chloride, and molybdenum nitrate.

[0022] Specifically, the interior of the bionic model is a primitive surface structure model or a gyroid surface structure model with a pore size of 600~800μm and high fluid permeability, and the exterior is a high-strength porous support with a pore size of 300~400μm, a wall thickness of 0.2~0.5mm, a total porosity of 50%~70%, and a connectivity rate between macroscopic voids higher than 95%.

[0023] Specifically, in the printing slurry preparation step, the photosensitive resin is composed of a combination of a reactive diluent and a high refractive index photosensitive resin, the reactive diluent is one of 1,6-hexanediol diacrylate and trimethyloltrimethacrylate trihydroxyethyl ester, the high refractive index photosensitive resin is a mixture of at least one of ethylene glycol diacrylate, hydroxyethyl methyl methacrylate, isooctanoic acid propylene ester, methyl methacrylate, propylene isobutyl ester, o-phenylphenoxyethyl acrylate, dimethylolpropane triacrylate, tricarboxymethane triacrylate, hydrogenated vinylphenyl methyl acrylate, and propylene oxide, and the dispersant is tributyl phosphate, hexadecyltriethyloxysilane sulfate, polyacrylamide, hydrolyzed carboxymethyl cellulose sodium, silane coupling agent KH560, Disuper S18, tris(2-methylpropyl)octyl phosphate, the photoinitiator is diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, dimethoxyethyl phenylphosphonate or triphenylamine, and the light absorber is 2-amino-4-methylazobenzene.

[0024] Specifically, in the 3D printing step, the printing parameters include a slice thickness of 0.03-0.1 mm, a laser power of 16-22 mW, a laser scanning speed of 3000-8000 mm / s, a laser spacing of 0.03 mm, and a contour compensation of 20-50 μm.

[0025] Specifically, in the debinding and sintering step, the four-stage debinding and sintering method includes:

[0026] S1, heating to 350℃~400℃ at a heating rate of 0.5~1℃ / min, and keeping warm for 1~3h;

[0027] S2, heating to 450℃ at a heating rate of 0.5~1℃ / min and keeping warm for 1~3h;

[0028] S3, heating to 500°C at a heating rate of 0.5-1°C / min and keeping at this temperature for 1-3 hours;

[0029] S4, heat up to 800℃ at a heating rate of 0.5~2℃ / min and keep warm for 2~3h.

[0030] Specifically, in the model fine-tuning step, the further design modification includes grid reconstruction, scaling and Boolean operations.

[0031] Another technical solution of the present invention to solve the above technical problems is:

[0032] A photocurable 3D printed minimal curved surface artificial bone scaffold, prepared by the above-mentioned preparation method, is a composite scaffold comprising calcium phosphate ceramics and bioactive glass, wherein the bioactive glass contains the elements Ca, P, Mg, and Mo. The composite scaffold has a structurally hybridized minimal curved surface structure.

[0033] Specifically, the shrinkage rate of the light-curved 3D printed minimal curved surface artificial bone scaffold is 5-11%, and the porosity is 50-70%.

[0034] The present invention has the following beneficial effects:

[0035] 1. The present invention introduces Mg and Mo ions into the calcium phosphate ceramic bone scaffold through the addition of bioactive glass. These ions are continuously released as the scaffold degrades during implantation, resulting in superior osteogenesis and osteoclast inhibition compared to traditional ceramic bone scaffolds. Furthermore, the addition of bioglass reduces the viscosity of the ceramic slurry and improves its printability.

[0036] 2. Through the rational regulation of the slurry system, a composite ceramic slurry was prepared with excellent rheological properties and printability. The semi-finished product produced by photocuring showed no obvious defects such as warping or missing layers, and had a high forming rate. Furthermore, through the optimization of appropriate printing parameters and the debinding and sintering process, a composite ceramic product with excellent mechanical properties and high surface precision was obtained. The product has a highly connected pore structure and a large specific surface area, with no obvious pore blockage or defects, a connectivity rate exceeding 95%, and a dimensional accuracy of 50-100μm.

[0037] 3. The finished product prepared by the present invention is conducive to the adhesion, proliferation and differentiation of cells. At the same time, compared with the traditional uniform structure scaffold, the structural hybrid design can effectively control the deformation mechanism and biomechanical properties, better simulate natural bone tissue, and create a favorable osteogenic microenvironment. Compared with the low-porosity structure, it reduces the excess mechanical properties, meets the distribution of certain mechanical and fluid permeability, and is more suitable for the repair of larger bone defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of SEM of the bioactive glass powder containing Mg and Mo in the present invention.

[0039] Figure 2 It is a structural schematic diagram of the product of the present invention. DETAILED DESCRIPTION

[0040] The present invention is described in detail below with reference to the embodiments.

[0041] A light-cured 3D-printed minimal curved surface artificial bone scaffold according to Example 1 of the present invention is prepared by the following steps:

[0042] The modeling parameters are obtained by determining the corresponding size, shape, pore size and porosity of the human bone based on the actual size and shape of the corresponding human bone and its location, and obtaining the modeling parameters. The data is mainly obtained for the human bone to be replaced, so as to determine the bionic data and perform actual bionic modeling. This mainly affects the shape and actual size of the bracket and is not specifically reflected in the present invention.

[0043] Modeling is performed using Matlab, Rhino, or Grasshopper software, and two or more TPMS implicit functions. Based on modeling parameters, a three-period minimum surface structure model with structural hybridization inside and a surface network model with a high-strength porous structure outside are constructed. Sigmod functions are used for radial transition connection, and a bionic model that meets the modeling parameters is obtained by adjusting the pore size, wall thickness, and porosity. The interior of the bionic model is a Gyroid surface structure model with a pore size of 600 μm and high fluid permeability, and the exterior is a high-strength porous support with a pore size of 400 μm, a wall thickness of 0.2 mm, a total porosity of 50%, and a connectivity rate between macroscopic voids greater than 95%.

[0044] The model is fine-tuned, the bionic model is exported in STL mode, and then the bionic model in this mode is further modified and designed to obtain a printing model, and then the printing model is simulated by finite element to obtain printing parameters; specifically, the further modification design includes mesh reconstruction, scaling and Boolean operations.

[0045] Printing slurry preparation, respectively, take 10% of Mg, Mo bioactive glass powder, 53% calcium phosphate ceramic powder, 30% photosensitive resin, 4% photoinitiator, 4% light absorber and 2% dispersant by weight ratio and mix them to obtain a mixture, then put the mixture and zirconium balls in a planetary ball mill at a mass ratio of 1:2 for ball milling, and ball milling at a speed of 300r / min for 3h to obtain a light-cured slurry; specifically, the Mg, Mo bioactive glass powder is made of sodium carbonate, calcium carbonate, basic magnesium carbonate, diammonium hydrogen phosphate and molybdenum source powder in a molar ratio of 2:1:1:5:1, and the preparation steps include: mixing, mixing 20wt% CaO, 10wt% Na2O, 10wt% P2 O3, 50wt% MgO and 10wt% MoO3 are sequentially put into ultrapure water for mixing to obtain a mixed solution; heating, using a heating furnace to heat and boil the mixed solution until the mixed solution is viscous to obtain a viscous liquid; melting, quickly transferring the viscous liquid to a corundum crucible in a muffle furnace, gradually heating it until the temperature rises to 900°C, and obtaining a molten solution; quenching, quickly placing the molten solution into deionized water for rapid cooling and quenching, and obtaining a bioactive glass containing Mg and Mo after complete cooling; ball milling, placing the bioactive glass containing Mg and Mo into a ball mill, and adding ethanol for ball milling, the ball milling speed is 300r / min, the ball milling time is 3h, and a bioactive glass powder containing Mg and Mo with a particle size of micron level is obtained. Figure 1 As shown; too fine powder will lead to too high viscosity of the slurry and reduced printing performance, so it is not suitable to ball mill for too long. In this embodiment, the selected molybdenum source is ammonium molybdate tetrahydrate.

[0046] Specifically, the photosensitive resin in this embodiment is composed of a reactive diluent and a high refractive index photosensitive resin in a ratio of 1:2, the reactive diluent is 1,6-hexanediol diacrylate, the high refractive index photosensitive resin is hydroxyethyl methyl methacrylate, the dispersant is Disuper S18, the photoinitiator is diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, and the light absorber is 2-amino-4-methylazobenzene.

[0047] 3D printing, the photocurable slurry is introduced into the material tank of the SLA printer, and the printing model is input into the SLA printer, and the printing parameters are adjusted for printing to obtain a semi-finished product after printing; specifically, the printing parameters include a slice thickness of 0.03mm, a laser power of 16mW, a laser scanning speed of 5000mm / s, a laser spacing of 0.04mm, and a contour compensation of 20μm.

[0048] Clean and dry the semi-finished product with cleaning liquid and use ultrasonic cleaning for 5 minutes to clean the residual slurry inside the pores and remove the residual resin. Then place it in an environment of 60°C and dry it for 12 hours to avoid the presence of excess corners after degreasing and sintering.

[0049] Degreasing and sintering: the dried semi-finished product is placed in a sintering furnace and sintered by a four-stage degreasing and sintering method. After sintering, it is cooled to room temperature with the furnace to obtain a light-curing 3D printed minimum surface artificial bone scaffold. Figure 2 Specifically, in this embodiment, the four-stage debinding sintering method includes: S1, heating to 350°C at a heating rate of 0.5°C / min and holding for 2 hours; S2, heating to 450°C at a heating rate of 0.5°C / min and holding for 2 hours; S3, heating to 500°C at a heating rate of 0.5°C / min and holding for 2 hours; S4, heating to 800°C at a heating rate of 1°C / min and holding for 2 hours. The final product has a shrinkage of 5-11% and a porosity of 50%.

[0050] A light-cured 3D-printed minimal curved surface artificial bone scaffold according to Example 2 of the present invention is prepared by the following steps:

[0051] The modeling parameters are obtained by determining the corresponding size, shape, pore size and porosity of the human bone based on the actual size and shape of the corresponding human bone and its location, and obtaining the modeling parameters. The data is mainly obtained for the human bone to be replaced, so as to determine the bionic data and perform actual bionic modeling. This mainly affects the shape and actual size of the bracket and is not specifically reflected in the present invention.

[0052] Modeling is carried out using Matlab, Rhino or Grasshopper software, and two or more TPMS implicit functions. According to the modeling parameters, a three-period minimum surface structure model with structural hybridization inside and a surface network model with a high-strength porous structure outside are constructed, and the Sigmod function is used for radial transition connection. By adjusting the pore size, wall thickness and porosity, a bionic model that meets the modeling parameters is obtained; the interior of the bionic model is a Gyroid surface structure model with a pore size of 700 μm and high fluid permeability, and the exterior is a high-strength porous support with a pore size of 350 μm, a wall thickness of 0.3 m, a total porosity of 60%, and a connectivity rate between macroscopic voids greater than 95%.

[0053] The model is fine-tuned, the bionic model is exported in STL mode, and then the bionic model in this mode is further modified and designed to obtain a printing model, and then the printing model is simulated by finite element to obtain printing parameters; specifically, the further modification design includes mesh reconstruction, scaling and Boolean operations.

[0054] Printing slurry preparation, respectively, take 15% of Mg, Mo bioactive glass powder, 45% calcium phosphate ceramic powder, 30% photosensitive resin, 3% photoinitiator, 3% light absorber and 4% dispersant by weight ratio and mix them to obtain a mixture, then put the mixture and zirconium balls in a mass ratio of 1:2 into a planetary ball mill for ball milling, and ball milling at a speed of 300r / min for 3h to obtain a light-cured slurry; specifically, the Mg, Mo bioactive glass powder is made of sodium carbonate, calcium carbonate, basic magnesium carbonate, diammonium hydrogen phosphate and molybdenum source powder in a molar ratio of 4:2:2:9:3. The preparation steps include: mixing, adding 20wt% CaO, 10wt% Na2O, 10wt% P2O3, 45wt% MgO and 15wt% MoO3 configured in a molar ratio in sequence The steps of: mixing the mixture in ultrapure water to obtain a mixed liquid; heating, heating the mixed liquid in a heating furnace to boil the mixed liquid until it becomes viscous to obtain a viscous liquid; melting, quickly transferring the viscous liquid to a corundum crucible in a muffle furnace, and gradually heating it until the temperature reaches 900°C to obtain a molten liquid; quenching, quickly placing the molten liquid into deionized water for rapid quenching, and obtaining a bioactive glass containing Mg and Mo after complete cooling; ball milling, placing the bioactive glass containing Mg and Mo into a ball mill, and adding ethanol for ball milling at a ball milling speed of 350 r / min and a ball milling time of 2 h to obtain a bioactive glass powder containing Mg and Mo with a particle size of micron order; excessively fine powder will lead to excessively high slurry viscosity and reduced printing performance, so the ball milling time should not be too long. In this embodiment, the selected molybdenum source is ammonium chloride molybdate.

[0055] Specifically, the photosensitive resin in this embodiment is composed of a reactive diluent and a high refractive index photosensitive resin in a ratio of 1:2, the reactive diluent is 1,6-hexanediol diacrylate, the high refractive index photosensitive resin is tricarboxymethane triacrylate, the dispersant is a silane coupling agent KH560, the photoinitiator is diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, and the light absorber is 2-amino-4-methylazobenzene.

[0056] 3D printing, the photocurable slurry is introduced into the material tank of the SLA printer, and the printing model is input into the SLA printer, and the printing parameters are adjusted for printing to obtain a semi-finished product after printing; specifically, the printing parameters include a slice thickness of 0.05mm, a laser power of 18mW, a laser scanning speed of 7000mm / s, a laser spacing of 0.02mm, and a contour compensation of 30μm.

[0057] Clean and dry the semi-finished product with cleaning liquid and use ultrasonic cleaning for 5 minutes to clean the residual slurry inside the pores and remove the residual resin. Then place it in an environment of 60°C and dry it for 12 hours to avoid the presence of excess corners after degreasing and sintering.

[0058] Degreasing and sintering: Place the dried semi-finished product into a sintering furnace and sinter it using a four-stage degreasing and sintering method. After sintering, cool it to room temperature in the furnace to obtain a light-cured 3D printed minimum curved artificial bone scaffold. Specifically, in this embodiment, the four-stage degreasing and sintering method includes: S1, heating to 360°C at a heating rate of 0.6°C / min and keeping warm for 2 hours; S2, heating to 450°C at a heating rate of 0.6°C / min and keeping warm for 2 hours; S3, heating to 500°C at a heating rate of 0.6°C / min and keeping warm for 2 hours; S4, heating to 800°C at a heating rate of 1°C / min and keeping warm for 2 hours. The final product has a shrinkage rate of 5-11% and a porosity of 60%.

[0059] A light-cured 3D-printed minimal curved surface artificial bone scaffold according to embodiment 3 of the present invention is prepared by the following steps:

[0060] The modeling parameters are obtained by determining the corresponding size, shape, pore size and porosity of the human bone based on the actual size and shape of the corresponding human bone and its location, and obtaining the modeling parameters. The data is mainly obtained for the human bone to be replaced, so as to determine the bionic data and perform actual bionic modeling. This mainly affects the shape and actual size of the bracket and is not specifically reflected in the present invention.

[0061] Modeling is carried out using Matlab, Rhino or Grasshopper software, and two or more TPMS implicit functions. According to the modeling parameters, a three-period minimum surface structure model with structural hybridization inside and a surface network model with a high-strength porous structure outside are constructed, and the Sigmod function is used for radial transition connection. By adjusting the pore size, wall thickness and pores, a bionic model that meets the modeling parameters is obtained; the interior of the bionic model is a primitive surface structure model with a pore size of 800 μm and high fluid permeability, and the exterior is a high-strength porous support with a pore size of 400 μm, a wall thickness of 0.5 mm, a total porosity of 70%, and a connectivity rate between macroscopic voids greater than 95%.

[0062] The model is fine-tuned, the bionic model is exported in STL mode, and then the bionic model in this mode is further modified and designed to obtain a printing model, and then the printing model is simulated by finite element to obtain printing parameters; specifically, the further modification design includes mesh reconstruction, scaling and Boolean operations.

[0063] Printing slurry preparation, respectively, take 20% of Mg, Mo bioactive glass powder, 46% calcium phosphate ceramic powder, 28% photosensitive resin, 0.5% photoinitiator, 0.5% light absorber and 5% dispersant by weight ratio and mix them to obtain a mixture, then put the mixture and zirconium balls in a mass ratio of 1:2 into a planetary ball mill for ball milling, and ball milling at a speed of 300r / min for 3h to obtain a light-cured slurry; specifically, the Mg, Mo bioactive glass powder is made of sodium carbonate, calcium carbonate, basic magnesium carbonate, diammonium hydrogen phosphate and molybdenum source powder in a molar ratio of 2:1:1:4:2, and the preparation steps include: mixing, and sequentially adding 20wt% CaO, 10wt% Na2O, 10wt% P2O3, 40wt% MgO and 20wt% MoO3 configured in molar ratio. The mixture is put into ultrapure water for mixing to obtain a mixed solution; heating, using a heating furnace to heat and boil the mixed solution until the mixed solution is viscous to obtain a viscous liquid; melting, quickly transferring the viscous liquid to a corundum crucible in a muffle furnace, and gradually heating it until the temperature reaches 900°C to obtain a molten solution; quenching, quickly placing the molten solution into deionized water for rapid quenching, and obtaining a bioactive glass containing Mg and Mo after complete cooling; ball milling, placing the bioactive glass containing Mg and Mo into a ball mill, and adding ethanol for ball milling at a ball milling speed of 300 r / min and a ball milling time of 3 h to obtain a bioactive glass powder containing Mg and Mo with a particle size of micron order; too fine a powder will cause the slurry viscosity to be too high and the printing performance to deteriorate, so the ball milling time should not be too long. In this embodiment, the selected molybdenum source is ammonium carbonate molybdate.

[0064] Specifically, the photosensitive resin described in this embodiment is composed of a reactive diluent and a high-refractive index photosensitive resin in a ratio of 1:2, the reactive diluent is trihydroxyethyl trimethacrylate, the high-refractive index photosensitive resin is tricarboxymethane triacrylate, the dispersant is tributyl phosphate, the photoinitiator is dimethoxyethyl phenylphosphonate, and the light absorber is 2-amino-4-methylazobenzene.

[0065] 3D printing, the photocurable slurry is introduced into the material tank of the SLA printer, and the printing model is input into the SLA printer, and the printing parameters are adjusted for printing to obtain a semi-finished product after printing; specifically, the printing parameters include a slice thickness of 0.05mm, a laser power of 20mW, a laser scanning speed of 8000mm / s, a laser spacing of 0.04mm, and a contour compensation of 40μm.

[0066] Clean and dry the semi-finished product with cleaning liquid and use ultrasonic cleaning for 5 minutes to clean the residual slurry inside the pores and remove the residual resin. Then place it in an environment of 60°C and dry it for 12 hours to avoid the presence of excess corners after degreasing and sintering.

[0067] Degreasing and sintering: the dried semi-finished product is placed in a sintering furnace and sintered by a four-stage degreasing and sintering method. After sintering, it is cooled to room temperature with the furnace to obtain a light-curing 3D printed minimum surface artificial bone scaffold. Figure 2 Specifically, in this embodiment, the four-stage debinding sintering method includes: S1, heating to 350°C at a heating rate of 0.8°C / min and holding for 2.5 hours; S2, heating to 450°C at a heating rate of 0.8°C / min and holding for 2.5 hours; S3, heating to 500°C at a heating rate of 0.8°C / min and holding for 2.5 hours; S4, heating to 800°C at a heating rate of 1°C / min and holding for 3 hours. The final product has a shrinkage of 5-11% and a porosity of 70%.

[0068] A photocurable 3D printed minimal curved surface artificial bone scaffold according to embodiment 4 of the present invention is prepared by the following steps:

[0069] The modeling parameters are obtained by determining the corresponding size, shape, pore size and porosity of the human bone based on the actual size and shape of the corresponding human bone and its location, and obtaining the modeling parameters. The data is mainly obtained for the human bone to be replaced, so as to determine the bionic data and perform actual bionic modeling. This mainly affects the shape and actual size of the bracket and is not specifically reflected in the present invention.

[0070] Modeling is carried out using Matlab, Rhino or Grasshopper software, and two or more TPMS implicit functions. According to the modeling parameters, a three-period minimum surface structure model with structural hybridization inside and a surface network model with a high-strength porous structure outside are constructed, and the Sigmod function is used for radial transition connection. By adjusting the pore size, wall thickness and pores, a bionic model that meets the modeling parameters is obtained; the interior of the bionic model is a primitive surface structure model with a pore size of 800 μm and high fluid permeability, and the exterior is a high-strength porous support with a pore size of 300 μm, a wall thickness of 0.3 mm, a total porosity of 50%, and a connectivity rate between macroscopic voids greater than 95%.

[0071] The model is fine-tuned, the bionic model is exported in STL mode, and then the bionic model in this mode is further modified and designed to obtain a printing model, and then the printing model is simulated by finite element to obtain printing parameters; specifically, the further modification design includes mesh reconstruction, scaling and Boolean operations.

[0072] Printing slurry preparation, respectively, take 25% of Mg, Mo bioactive glass powder, 40% calcium phosphate ceramic powder, 28% photosensitive resin, 0.5% photoinitiator, 0.5% light absorber and 6% dispersant by weight ratio and mix them to obtain a mixture, then put the mixture and zirconium balls in a mass ratio of 1:2 into a planetary ball mill for ball milling, and ball milling at a speed of 300r / min for 3h to obtain a light-cured slurry; specifically, the Mg, Mo bioactive glass powder is made of sodium carbonate, calcium carbonate, basic magnesium carbonate, diammonium hydrogen phosphate and molybdenum source powder in a molar ratio of 2:1:1:4:2, and the preparation steps include: mixing, and sequentially adding 20wt% CaO, 10wt% Na2O, 10wt% P2O3, 40wt% MgO and 20wt% MoO3 configured in molar ratio. The mixture is put into ultrapure water for mixing to obtain a mixed solution; heating, using a heating furnace to heat and boil the mixed solution until the mixed solution is viscous to obtain a viscous liquid; melting, quickly transferring the viscous liquid to a corundum crucible in a muffle furnace, and gradually heating it until the temperature reaches 900°C to obtain a molten solution; quenching, quickly placing the molten solution into deionized water for rapid quenching, and obtaining a bioactive glass containing Mg and Mo after complete cooling; ball milling, placing the bioactive glass containing Mg and Mo into a ball mill, and adding ethanol for ball milling at a ball milling speed of 300 r / min and a ball milling time of 3 h to obtain a bioactive glass powder containing Mg and Mo with a particle size of micron order; too fine a powder will cause the slurry viscosity to be too high and the printing performance to deteriorate, so the ball milling time should not be too long. In this embodiment, the selected molybdenum source is ammonium carbonate molybdate.

[0073] Specifically, the photosensitive resin described in this embodiment is composed of a reactive diluent and a high-refractive index photosensitive resin in a ratio of 1:2, the reactive diluent is trihydroxyethyl trimethacrylate, the high-refractive index photosensitive resin is hydrogenated vinylphenyl methyl acrylate, the dispersant is hexadecyltriethyloxysilane sulfate, the photoinitiator is triphenylamine, and the light absorber is 2-amino-4-methylazobenzene.

[0074] 3D printing, the photocurable slurry is introduced into the material tank of the SLA printer, and the printing model is input into the SLA printer, and the printing parameters are adjusted for printing to obtain a semi-finished product after printing; specifically, the printing parameters include a slice thickness of 0.1mm, a laser power of 18mW, a laser scanning speed of 6000mm / s, a laser spacing of 0.04mm, and a contour compensation of 30μm.

[0075] Clean and dry the semi-finished product with cleaning liquid and use ultrasonic cleaning for 5 minutes to clean the residual slurry inside the pores and remove the residual resin. Then place it in an environment of 60°C and dry it for 12 hours to avoid the presence of excess corners after degreasing and sintering.

[0076] Degreasing and sintering: the dried semi-finished product is placed in a sintering furnace and sintered by a four-stage degreasing and sintering method. After sintering, it is cooled to room temperature with the furnace to obtain a light-curing 3D printed minimum surface artificial bone scaffold. Figure 2 Specifically, in this embodiment, the four-stage debinding sintering method includes: S1, heating to 350°C at a heating rate of 1°C / min and holding for 3 hours; S2, heating to 450°C at a heating rate of 1°C / min and holding for 3 hours; S3, heating to 500°C at a heating rate of 1°C / min and holding for 3 hours; S4, heating to 800°C at a heating rate of 0.8°C / min and holding for 3 hours. The final product has a shrinkage of 5-11% and a porosity of 50%.

[0077] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for preparing a minimal curved surface artificial bone scaffold by photocuring 3D printing, characterized in that: The steps include: Modeling parameter acquisition: based on the actual size, shape, and location of the corresponding human bone, the corresponding size, shape, pore size, and porosity of the human bone are determined to obtain modeling parameters; Modeling: using Matlab, Rhino, or Grasshopper software, using two or more TPMS implicit functions, and based on modeling parameters, constructing a three-periodic minimum surface structure model with structural hybridization inside and a surface network model with a high-strength porous structure outside, and using Sigmod functions for radial transition connection. By adjusting the pore size, wall thickness, and porosity, a biomimetic model that meets the modeling parameters is obtained. The high-strength porous structure is a high-strength porous support with a pore size of 300-400 μm, a wall thickness of 0.2-0.5 mm, a total porosity of 50%-70%, and a connectivity rate between macroscopic voids greater than 95%; Model fine-tuning: export the bionic model in STL mode, then further modify and design the bionic model in this mode to obtain a printing model, and then perform finite element simulation on the printing model to obtain printing parameters; The printing slurry is prepared by mixing 5-25% of bioactive glass powder containing Mg and Mo, 40-53% of calcium phosphate ceramic powder, 5-30% of photosensitive resin, 0.2-5% of photoinitiator, 0.2-5% of light absorber and 2-6% of dispersant in a weight ratio to obtain a mixture, and then ball milling the mixture to obtain a light-curing slurry; 3D printing: the photocurable slurry is introduced into the material tank of the SLA printer, and the printing model is input into the SLA printer. The printing parameters are adjusted for printing, and the semi-finished product is obtained after printing; Clean and dry the semi-finished product with cleaning liquid to remove residual resin, and then dry it in an environment of 60℃ for 12 hours; Degreasing and sintering: Place the dried semi-finished product into a sintering furnace and sinter it using a four-stage degreasing and sintering method. After sintering, cool it to room temperature with the furnace to obtain a light-curing 3D printed minimum curved artificial bone scaffold.

2. The method for preparing a light-curved 3D-printed minimal curved artificial bone scaffold according to claim 1, characterized in that: In the printing slurry preparation step, the bioactive glass powder containing Mg and Mo is prepared from sodium carbonate, calcium carbonate, basic magnesium carbonate, diammonium hydrogen phosphate and molybdenum source powder in a molar ratio of (1-10):(1-10):(1-20):(1-15):(0.1-5), and the preparation steps include: Mixing, adding CaO, Na2O, P2O3, MgO and MoO3 prepared in molar proportions into ultrapure water in sequence and mixing to obtain a mixed solution; Heating: using a heating furnace to heat and boil the mixed liquid until the mixed liquid becomes viscous to obtain a viscous liquid; Melt, quickly transfer the viscous liquid to a corundum crucible in a muffle furnace, and gradually heat it until the temperature reaches 900°C to obtain a molten liquid; Quenching, quickly placing the melt into deionized water for rapid cooling and quenching, and obtaining bioactive glass containing Mg and Mo after complete cooling; Ball milling: placing the bioactive glass containing Mg and Mo into a ball mill and adding ethanol for ball milling at a ball milling speed of 200-350 r / min for 1.5-3 h to obtain a bioactive glass powder containing Mg and Mo with a particle size of micrometers; The selected molybdenum source is one of ammonium molybdate tetrahydrate, molybdenum trioxide, ammonium molybdate carbonate, ammonium molybdate chloride, and molybdenum nitrate.

3. The method for preparing a light-curved 3D-printed minimal curved artificial bone scaffold according to claim 1, characterized in that: The interior of the bionic model is a primitive surface structure model or a gyroid surface structure model with a pore size of 600-800 μm and high fluid permeability.

4. The method for preparing a light-cured 3D-printed minimal curved surface artificial bone scaffold according to claim 1, characterized in that: In the printing slurry preparation step, the photosensitive resin is composed of a reactive diluent and a high refractive index photosensitive resin, the reactive diluent is one of 1,6-hexanediol diacrylate and trimethylol acrylate tris(hydroxyethyl), the high refractive index photosensitive resin is a mixture of ethylene glycol diacrylate, hydroxyethyl methyl methacrylate, isooctanoic acid propylene ester, methyl methacrylate, propylene isobutyl ester, o-phenylphenoxyethyl acrylate, dimethylolpropane triacrylate, tricarboxymethane triacrylate, hydrogenated vinylphenyl methyl acrylate, and propylene oxide, the dispersant is tributyl phosphate, hexadecyltriethyloxysilane sulfate, polyacrylamide, hydrolyzed carboxymethyl cellulose sodium, silane coupling agent KH560, Disuper S18, tris(2-methylpropyl)octyl phosphate, the photoinitiator is diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, dimethoxyethyl phenylphosphonate or triphenylamine, and the light absorber is 2-amino-4-methylazobenzene.

5. The method for preparing a light-curved 3D-printed minimal curved artificial bone scaffold according to claim 1, characterized in that: In the 3D printing step, the printing parameters include a slice thickness of 0.03-0.1 mm, a laser power of 16-22 mW, a laser scanning speed of 3000-8000 mm / s, a laser spacing of 0.03 mm, and a contour compensation of 20-50 μm.

6. The method for preparing a light-curved 3D printed minimal curved surface artificial bone scaffold according to claim 1, characterized in that: In the degreasing and sintering step, the four-stage degreasing and sintering method includes: S1, heating to 350℃~400℃ at a heating rate of 0.5~1℃ / min, and keeping warm for 1~3h; S2, heating to 450℃ at a heating rate of 0.5~1℃ / min and keeping warm for 1~3h; S3, heating to 500°C at a heating rate of 0.5-1°C / min and keeping at this temperature for 1-3 hours; S4, heat up to 800℃ at a heating rate of 0.5~2℃ / min and keep warm for 2~3h.

7. The method for preparing a light-curved 3D-printed minimal curved artificial bone scaffold according to claim 1, characterized in that: In the model fine-tuning step, the further design modification includes mesh reconstruction, scaling and Boolean operations.

8. A light-curved 3D-printed minimal-curved artificial bone scaffold, characterized by: The composite scaffold is prepared by the preparation method according to any one of claims 1 to 7, and comprises calcium phosphate ceramics and bioactive glass, wherein the bioactive glass comprises the elements Ca, P, Mg, and Mo, and the composite scaffold has a structurally hybrid minimum surface structure.

9. The light-curing 3D printing minimum curved surface artificial bone scaffold according to claim 8, characterized in that: The shrinkage rate of the light-curved 3D-printed minimal curved artificial bone scaffold is 5-11%, and the porosity is 50-70%.

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