Intelligent double-response nanometer material artificial bone with three-layer structure and preparation method of intelligent double-response nanometer material artificial bone

Abstract

The invention discloses an intelligent double-response nanometer material artificial bone with a three-layer structure and a preparation method thereof, and relates to the technical field of medical materials, the intelligent double-response nanometer material artificial bone with the three-layer structure sequentially comprises a core support layer, an intelligent response drug layer and a surface bioactive coating from inside to outside; the core support layer contains 55-67 parts of polycaprolactone, 30-40 parts of alpha-tricalcium phosphate and 3-5 parts of magnesium hydroxide; the intelligent response drug layer is pH / temperature double-response nano-micelles loaded in pores of the core support layer and contains 95 to 105 parts of poly (2-(dimethylamino) ethyl methacrylate)-polyglutamic acid block copolymer, 5 to 8 parts of rifampicin and 0.1 to 0.3 part of anti-inflammatory factor; according to the invention, a three-layer composite structure is matched with precise components, so that degradation-regeneration matching and intelligent drug release are realized, a precise process is supplemented to guarantee stable performance, and the artificial bone repair efficiency and the mass production feasibility are improved.

Description

Technical Field

[0001] This invention relates to the field of medical materials technology, specifically to a three-layer intelligent dual-response nanomaterial artificial bone and its preparation method. Background Technology

[0002] Bone defect repair is a crucial research area in orthopedic clinical practice. With an aging population, rising incidence of traumatic bone injuries, and increasing demand for post-operative repair after bone tumor surgery, the need for high-performance bone repair materials is becoming increasingly urgent. Artificial bone, as a key alternative material for bone defect repair, must simultaneously meet multiple requirements, including mechanical support, biocompatibility, degradation compatibility, and bioactivity. In recent years, the field of medical materials has conducted extensive research on optimizing the function of artificial bone, evolving from early single-component inorganic ceramics (such as calcium phosphate) and polymers (such as polylactic acid) to multi-component composite systems, aiming to achieve complementary performance through material composites. Meanwhile, intelligent responsive materials, capable of dynamically adjusting their function according to the in vivo physiological microenvironment, have become a new trend in artificial bone development.

[0003] However, traditional artificial bone materials still have many limitations that are difficult to overcome. In terms of material composition, single-component materials cannot simultaneously achieve multiple properties. For example, inorganic ceramics have high mechanical strength but are brittle and have a slow degradation rate, making it difficult to match the bone regeneration process. High molecular polymers have poor controllability in degradation, which can easily lead to premature loss of support or degradation products causing local inflammation. In terms of functional design, most traditional artificial bones only have osteoconductive properties and lack key biological activities such as antibacterial and angiogenesis promotion, resulting in a high postoperative infection rate and seriously affecting the repair effect. Some drug-loaded artificial bones use passive diffusion drug release, which cannot dynamically adjust the drug release rate according to the inflammatory microenvironment, easily causing premature drug depletion or excessively high local drug concentration, increasing the risk of toxic side effects. In terms of structural design, the pore structure of traditional artificial bones is mostly randomly distributed, and the pore size and connectivity are difficult to control precisely, which is not conducive to bone cell adhesion, proliferation and nutrient transport. Moreover, there is a lack of interlayer synergistic design, with each functional module being independent and unable to form an efficient synergistic repair effect. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a three-layer intelligent dual-response nanomaterial artificial bone and its preparation method. The invention utilizes a three-layer composite structure consisting of a core support layer, an intelligent responsive drug layer, and a surface bioactive coating. The core support layer is composed of polycaprolactone, tricalcium α-phosphate, and magnesium hydroxide in a specific ratio to ensure a balance between degradation and bone regeneration. The intelligent responsive drug layer is composed of dual-response nanomicelles loaded with rifampin and transforming growth factor-β. The surface coating contains hyaluronic acid and bioactive glass nanoparticles. The preparation process employs ultra-low temperature 3D printing and vacuum impregnation to ensure the stability of each layer, achieving intelligent drug release and bone-promoting functions in the artificial bone, thus improving the bone defect repair effect and mass production feasibility.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: On the one hand, the artificial bone includes, from the inside out, a core support layer, a smart responsive drug layer and a surface bioactive coating;

[0006] The core support layer is composed of the following components in the following weight range: 55-67 parts of polycaprolactone, 30-40 parts of tricalcium α-phosphate, and 3-5 parts of magnesium hydroxide.

[0007] The intelligent responsive drug layer is a pH / temperature dual-responsive nanomicelle loaded in the pores of the core support layer. The nanomicelle is composed of 95-105 parts of poly(2-(dimethylamino)ethyl methacrylate)-polyglutamic acid block copolymer, 5-8 parts of rifampin, and 0.1-0.3 parts of anti-inflammatory factor.

[0008] The surface bioactive coating is composed of the following components in parts by weight: 70-80 parts hyaluronic acid and 20-30 parts bioactive glass nanoparticles.

[0009] Furthermore, the number-average molecular weight of the polycaprolactone is 80,000-120,000.

[0010] Furthermore, the porosity of the core support layer is 60%-70%, and the pore size is 200-500μm.

[0011] Furthermore, the molar ratio of poly(2-dimethylaminoethyl methacrylate) to polyglutamic acid in the poly(2-dimethylaminoethyl methacrylate)-b-polyglutamic acid is 2.8-3.2:1.

[0012] Furthermore, the rifampicin accounts for 5-8% by weight in the nanomicelles; the anti-inflammatory factor is transforming growth factor-β, which accounts for 0.1-0.3% by weight in the nanomicelles.

[0013] Furthermore, the thickness of the surface bioactive coating is 50-100 nm.

[0014] On the other hand, a method for preparing artificial bone made of a three-layer intelligent dual-response nanomaterial includes:

[0015] (1) Preparation of core support layer: Weigh 55-67 parts of polycaprolactone, 30-40 parts of tricalcium α-phosphate and 3-5 parts of magnesium hydroxide by weight, add a mixed solvent composed of acetone and N-methylpyrrolidone, wherein the volume ratio of acetone to N-methylpyrrolidone in the mixed solvent is 3.8-4.2:1, stir until completely dissolved to form a printing slurry with a solid content of 25%-30%; use an ultra-low temperature 3D printer to print a porous scaffold green body, wherein the 3D printing temperature is -10℃ to -5℃, the nozzle diameter is 0.18-0.22mm, the layer thickness is 0.13-0.17mm, and the printing speed is 4.5-5.5mm / s; freeze-dry the porous scaffold green body at a temperature of -55℃ to -45℃ and a vacuum degree of 8-12Pa for 22-26h, and then anneal it in a vacuum oven at 35-39℃ for 7-9h to obtain the core support layer;

[0016] (2) Preparation of nanomicelles: Weigh 95-105 parts of poly(2-dimethylaminoethyl methacrylate)-b-polyglutamic acid according to the weight ratio and dissolve it in deionized water to prepare a polymer solution with a concentration of 9-11 mg / mL; add 5-8 parts of rifampicin and 0.1-0.3 parts of transforming growth factor-β to the polymer solution, and ultrasonically disperse it for 8-12 min under the power of 280-320W. Then stir it in a water bath at 36-38℃ for 1.8-2.2 h. The nanomicelles prepared have a particle size of 80-120 nm and a particle size distribution index of 0.15-0.20.

[0017] (3) Drug-loaded layer: The core support layer is placed in the nanomicelle solution prepared in step (2) and vacuum impregnated for 3.5-4.5 h under vacuum conditions of 45-55 Pa and 23-27 °C. Then, it is freeze-dried for 10-14 h under conditions of -45 °C to -35 °C and vacuum conditions of 13-17 Pa to obtain a scaffold with a drug-loaded layer.

[0018] (4) Coating: Weigh 70-80 parts of hyaluronic acid and 20-30 parts of bioactive glass nanoparticles by weight, add 0.8%-1.2% sodium hydroxide solution, and ultrasonically disperse for 13-17 min at a power of 380-420W to form a coating solution with a concentration of 4.5-5.5 mg / mL; immerse the drug-loaded scaffold in the coating solution and coat it at a speed of 4.5-5.5 mm / s, and dry it at 35-39℃ for 5-7 h, repeating the coating 2-3 times; then place the coated scaffold in 2.3%-2.7% carbodiimide vapor for cross-linking treatment for 1.8-2.2 h, and finally obtain a three-layer structure intelligent dual-response nanomaterial artificial bone.

[0019] Furthermore, the magnesium hydroxide described in step (1) has an average particle size of 50-100 nm and a purity of ≥99.5%.

[0020] Furthermore, the printing path of the ultra-low temperature 3D printer described in step (1) adopts an orthogonal grid structure with a grid spacing of 200-400μm.

[0021] Furthermore, the adhesion between the bioactive coating formed in step (4) and the scaffold is 5-7 MPa.

[0022] Compared with existing technologies, this three-layer intelligent dual-response nanomaterial artificial bone and its preparation method have the following beneficial effects:

[0023] I. This invention designs a three-layer composite structure and optimizes the component combination. The core support layer is a compound of polycaprolactone, tricalcium α-phosphate, and magnesium hydroxide. By leveraging the controllable degradability of polycaprolactone, the osteoconductive properties of tricalcium α-phosphate, and the precise regulation of degradation rate by magnesium hydroxide, a high degree of matching between the degradation and regeneration cycle of artificial bone is achieved. At the same time, the 60%-70% porosity and 200-500μm pore size provide ample space for bone cell growth. The intelligent responsive drug layer uses poly(2-dimethylaminoethyl methacrylate)-b-polyglutamic acid to construct pH / temperature dual-responsive nanomicelles, which can dynamically adjust the release of rifampin and transforming growth factor-β according to the inflammatory microenvironment, solving the problem of blind drug release in traditional artificial bone. The surface bioactive coating uses hyaluronic acid and bioactive glass nanoparticles in synergy, which have both antibacterial and osteogenic functions. The three-layer structure performs its own functions and works together to comprehensively improve the biocompatibility and repair efficiency of artificial bone.

[0024] II. This invention achieves technological breakthroughs through precise processes such as ultra-low temperature 3D printing and vacuum impregnation. Ultra-low temperature 3D printing, using a printing temperature of -10℃ to -5℃, orthogonal mesh paths, and specific parameters, avoids magnesium hydroxide oxidation failure and ensures uniform pore structure of the core support layer. The combination of vacuum impregnation and gradient freeze-drying processes ensures that nanomicelles are uniformly loaded into the pores of the core support layer without compromising drug activity. The coating process controls the lifting speed, drying temperature, and carbodiimide crosslinking conditions to achieve a surface coating adhesion of 5-7 MPa, preventing coating detachment during use. At the same time, the range-based design of parameters in each step reduces the difficulty of process control and allows for flexible adaptation to the characteristics of different batches of materials, ensuring consistent product performance during mass production and providing reliable process support for the clinical translation of artificial bone.

[0025] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0027] Figure 1 A flowchart illustrating a three-layer intelligent dual-response nanomaterial artificial bone and its preparation method;

[0028] Figure 2 This is a flowchart of the coating preparation process. Detailed Implementation

[0029] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0030] Example 1:

[0031] Raw material ratio

[0032] Core support layer: 61 parts polycaprolactone (number average molecular weight 100,000), 35 parts tricalcium α-phosphate, and 4 parts magnesium hydroxide (average particle size 50-100 nm, purity ≥99.5%).

[0033] Smart responsive drug layer: 100 parts of poly(2-(dimethylamino)ethyl methacrylate)-polyglutamic acid block copolymer (molar ratio 3:1), 6.5 parts of rifampin, and 0.2 parts of transforming growth factor-β;

[0034] Surface coating: 75 parts hyaluronic acid, 25 parts bioactive glass nanoparticles (40nm, composition including 48% SiO2, 2% CaO, 2% Na2O, and 58% P2O).

[0035] The specific preparation steps are as follows: Figure 1 As shown:

[0036] Core support layer preparation: The core support layer raw materials were added to a mixed solvent of acetone and N-methylpyrrolidone (volume ratio 4:1) and stirred until completely dissolved to form a printing slurry with a solid content of 28%. A porous scaffold green body was printed using an ultra-low temperature 3D printer at a printing temperature of -8℃, a nozzle diameter of 0.2mm, a layer thickness of 0.15mm, a printing speed of 5mm / s, and an orthogonal path with a grid spacing of 300μm. The green body was freeze-dried at -50℃ and 10Pa for 24 hours, and then annealed in a vacuum oven at 37℃ for 8 hours to obtain the core support layer (porosity 65%, pore size 300-400μm).

[0037] Preparation of nanomicelles: Poly(2-dimethylaminoethyl methacrylate)-b-polyglutamic acid was dissolved in deionized water to prepare a polymer solution of 10 mg / mL. Rifampicin and transforming growth factor-β were added, and the mixture was ultrasonically dispersed at 300 W for 10 min and stirred in a water bath at 37 °C for 2 h to obtain nanomicelles with a particle size of 100 nm and a particle size distribution index of 0.18.

[0038] Drug-loaded layer: The core support layer was placed in a nano micelle solution, vacuum impregnated at 50 Pa and 25 °C for 4 h, and then freeze-dried at -40 °C and 15 Pa for 12 h to obtain a scaffold with a drug-loaded layer.

[0039] Coating: Hyaluronic acid and bioactive glass nanoparticles were added to a 1% sodium hydroxide solution and ultrasonically dispersed at 400W for 15 min to obtain a 5 mg / mL coating solution. The scaffold was coated by lifting at a speed of 5 mm / s, dried at 37℃ for 6 h, and the coating was repeated twice. Then, it was cross-linked in 2.5% carbodiimide vapor (23℃) for 2 h to finally obtain artificial bone (coating adhesion 6 MPa). Figure 2 As shown.

[0040]

[0041]

[0042] In this embodiment, raw materials were weighed according to specific weight proportions: the core support layer consisted of 61 parts polycaprolactone, 35 parts tricalcium α-phosphate, and 4 parts magnesium hydroxide; the intelligent responsive drug layer consisted of 100 parts poly(2-dimethylaminoethyl methacrylate)-β-polyglutamic acid (molar ratio 3:1), 6.5 parts rifampin, and 0.2 parts transforming growth factor-β; and the surface coating consisted of 75 parts hyaluronic acid and 25 parts bioactive glass nanoparticles. During preparation, the core support layer and nanomicelles were first formed, followed by loading the drug layer and applying the coating, ultimately resulting in artificial bone with a coating adhesion of 6 MPa. Precise parameters in each step ensured product performance.

[0043] Example 2:

[0044] Raw material ratio

[0045] Core support layer: 61 parts polycaprolactone (number average molecular weight 100,000), 35 parts tricalcium α-phosphate, and 3 parts magnesium hydroxide (average particle size 50-100 nm, purity ≥99.5%).

[0046] Smart responsive drug layer: 100 parts of poly(2-(dimethylamino)ethyl methacrylate)-polyglutamic acid block copolymer (molar ratio 3:1), 6.5 parts of rifampin, and 0.2 parts of transforming growth factor-β;

[0047] Surface coating: 75 parts hyaluronic acid, 25 parts bioactive glass nanoparticles (40nm, composition including 48% SiO2, 2% CaO, 2% Na2O, and 58% P2O).

[0048] The specific preparation steps are as follows:

[0049] Preparation of the core support layer: Polycaprolactone, tricalcium α-phosphate, and magnesium hydroxide for the core support layer were added to a mixed solvent of acetone and N-methylpyrrolidone (volume ratio 4:1). The mixture was stirred at 300 rpm for 60 min at room temperature until the raw materials were completely dissolved, forming a printing slurry with a solid content of 28%. A cryogenic 3D printer was used, with the printing temperature set to -8℃, nozzle diameter 0.2 mm, layer thickness 0.15 mm, and printing speed 5 mm / s. The printing path was an orthogonal mesh structure with a grid spacing of 300 μm, forming a porous scaffold green body. The porous scaffold green body was transferred to a freeze dryer and freeze-dried at -50℃ and a vacuum of 10 Pa for 24 h to remove the solvent while retaining the porous structure. Subsequently, the dried green body was placed in a vacuum oven at 37℃ and annealed for 8 h to eliminate internal stress, finally obtaining a core support layer with a porosity of 64% and a pore size of 280-380 μm.

[0050] Preparation of nanomicelles: Poly(2-dimethylaminoethyl methacrylate)-b-polyglutamic acid was weighed and dissolved in deionized water, and stirred for 30 min to prepare a polymer solution with a concentration of 10 mg / mL. Rifampin and transforming growth factor-β were added to the solution, and the mixture was placed in an ultrasonic disperser and ultrasonically dispersed for 10 min at a power of 300 W to ensure uniform drug dispersion. Subsequently, the solution was transferred to a constant temperature water bath and stirred at 200 r / min for 2 h at 37 °C to allow the block copolymer to self-assemble into nanomicelles. The obtained nanomicelles had a particle size of 100 nm and a particle size distribution index of 0.18.

[0051] Drug-loaded layer: The prepared core support layer was placed in a sealed container containing a nano micelle solution and placed in a vacuum drying oven. The vacuum degree was set to 50 Pa and the temperature to 25 °C, and the container was vacuum-impregnated for 4 h to allow the nano micelles to fully penetrate into the pores of the core support layer. Subsequently, the loaded scaffold was transferred to a freeze dryer and freeze-dried at -40 °C and a vacuum degree of 15 Pa for 12 h to remove the water in the solution, thus obtaining a scaffold with a drug-loaded layer.

[0052] Coating: Hyaluronic acid and bioactive glass nanoparticles were weighed and added to a 1% sodium hydroxide solution. The mixture was then placed in an ultrasonic disperser and ultrasonically dispersed for 15 minutes at 400W to form a uniform coating solution with a concentration of 5 mg / mL. The drug-loaded scaffold was vertically immersed in the coating solution and uniformly lifted at a speed of 5 mm / s. After lifting, the scaffold was placed in a 37°C forced-air drying oven for 6 hours to allow the coating to initially cure. The lifting-drying operation was repeated twice to ensure the coating thickness met the requirements. Finally, the coated scaffold was placed in a sealed environment containing 2.5% carbodiimide vapor (temperature 23°C) for 2 hours for crosslinking treatment to enhance the adhesion between the coating and the scaffold, ultimately obtaining a three-layer intelligent dual-response nanomaterial artificial bone with a coating adhesion of 5.8 MPa.

[0053] In this embodiment, the core support layer is made of 61 parts polycaprolactone, 35 parts tricalcium α-phosphate, and 3 parts magnesium hydroxide. The proportions of the raw materials for the remaining layers are the same as in Example 1. During preparation, the core layer raw materials are first made into a 28% solids content printing slurry, which is then subjected to -8℃ ultra-low temperature 3D printing, -50℃ freeze-drying, and 37℃ annealing to obtain a core layer with a porosity of 64% and a pore size of 280-380 μm. Subsequent preparation of nanomicelles, drug loading, and coating parameters are the same as in Example 1. The final artificial bone coating exhibits an adhesion of 5.8 MPa and a slightly slower degradation rate, making it suitable for scenarios with longer bone regeneration cycles.

[0054] Example 3:

[0055] Raw material ratio

[0056] Core support layer: 61 parts polycaprolactone (number average molecular weight 100,000), 35 parts tricalcium α-phosphate, and 5 parts magnesium hydroxide (average particle size 50-100 nm, purity ≥99.5%).

[0057] Smart responsive drug layer: 100 parts of poly(2-(dimethylamino)ethyl methacrylate)-polyglutamic acid block copolymer (molar ratio 3:1), 6.5 parts of rifampin, and 0.2 parts of transforming growth factor-β;

[0058] Surface coating: 75 parts hyaluronic acid, 25 parts bioactive glass nanoparticles (40nm, composition including 48% SiO2, 2% CaO, 2% Na2O, and 58% P2O).

[0059] The specific preparation steps are as follows:

[0060] Preparation of the core support layer: Polycaprolactone, tricalcium α-phosphate, and magnesium hydroxide for the core support layer were added to a mixed solvent of acetone and N-methylpyrrolidone (volume ratio 4:1). The mixture was stirred at 300 rpm for 65 min at room temperature to ensure complete dissolution of the raw materials, forming a printing slurry with a solid content of 28%. A cryogenic 3D printer was used with the following printing parameters set: printing temperature -8℃, nozzle diameter 0.2 mm, layer thickness 0.15 mm, printing speed 5 mm / s, and an orthogonal mesh structure with a grid spacing of 300 μm to print a porous scaffold green body. The green body was then placed in a freeze dryer and freeze-dried at -50℃ and a vacuum of 10 Pa for 24 h to remove the solvent from the slurry. The green body was then transferred to a vacuum oven at 37℃ and annealed for 8 h to eliminate internal stress, ultimately yielding a core support layer with a porosity of 66% and a pore size of 320-420 μm.

[0061] Preparation of nanomicelles: Poly(2-dimethylaminoethyl methacrylate)-b-polyglutamic acid was weighed and dissolved in deionized water, and stirred for 35 min to prepare a polymer solution with a concentration of 10 mg / mL. Rifampin and transforming growth factor-β were added to the solution, and the mixture was ultrasonically dispersed for 10 min at a power of 300 W to ensure uniform dispersion of the drugs in the polymer solution. Subsequently, the solution was placed in a 37°C constant temperature water bath and stirred at a speed of 200 r / min for 2 h to promote the self-assembly of the block copolymer to form nanomicelles. The obtained nanomicelles had a particle size of 100 nm and a particle size distribution index of 0.18.

[0062] Drug-loaded layer: The core support layer was placed in a sealed container filled with a nanomicelle solution and placed in a vacuum drying oven. The vacuum degree was set to 50 Pa and the temperature to 25 °C, and the container was vacuum-impregnated for 4 hours to allow the nanomicelles to fully fill the pores of the core support layer. Then, the scaffold was transferred to a freeze dryer and freeze-dried at -40 °C and 15 Pa for 12 hours to remove moisture and fix the nanomicelles, thus obtaining a scaffold with a drug-loaded layer.

[0063] Coating: Hyaluronic acid and bioactive glass nanoparticles were weighed and added to a 1% sodium hydroxide solution. The mixture was ultrasonically dispersed for 15 minutes at 400W to prepare a coating solution with a concentration of 5 mg / mL. The drug-loaded scaffold was vertically immersed in the coating solution and uniformly lifted at a speed of 5 mm / s. After lifting, the scaffold was placed in a 37℃ forced-air drying oven for 6 hours. This coating and drying process was repeated twice. Finally, the scaffold was placed in an environment containing 2.5% carbodiimide vapor (temperature 23℃) for crosslinking treatment for 2 hours to improve coating adhesion. The final result was a three-layer intelligent dual-response nanomaterial artificial bone with a coating adhesion of 6.2 MPa.

[0064] In this embodiment, the amount of magnesium hydroxide used in the core support layer is 5 parts, while the proportions of polycaprolactone, tricalcium α-phosphate, and other layer raw materials remain unchanged. During preparation, the core layer slurry undergoes ultra-low temperature 3D printing and other processes, resulting in a porosity of 66% and a pore size of 320-420 μm. The parameters for nanomicelle preparation, drug loading, and coating steps are the same as in Example 1. The final artificial bone coating adhesion is 6.2 MPa. Due to the increased magnesium content, the degradation rate is accelerated, which is suitable for the defect repair needs of faster bone regeneration.

[0065]

[0066]

[0067] Three embodiments were used, varying only the weight percentage of magnesium hydroxide in the core support layer (3, 4, and 5 parts) to verify its regulatory effect on the performance of artificial bone. Results showed that the core support layer had a porosity of 64%-66% and a pore size of 280-420 μm, with a surface coating adhesion of 5.8-6.2 MPa. The degradation rate over 8 weeks increased from 58±3% to 72±3% with increasing magnesium hydroxide content, adaptable to different bone regeneration cycles. All embodiments showed antibacterial rates of over 97% against Staphylococcus aureus and Escherichia coli, demonstrating stable antibacterial properties and biocompatibility.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A three-layered intelligent dual-response nanomaterial artificial bone, characterized in that, The artificial bone consists of a core support layer, a smart responsive drug layer, and a surface bioactive coating, from the inside out. The core support layer is composed of the following components in the following weight range: 55-67 parts of polycaprolactone, 30-40 parts of tricalcium α-phosphate, and 3-5 parts of magnesium hydroxide. The intelligent responsive drug layer is a pH / temperature dual-responsive nanomicelle loaded in the pores of the core support layer. The nanomicelle is composed of 95-105 parts of poly(2-(dimethylamino)ethyl methacrylate)-polyglutamic acid block copolymer, 5-8 parts of rifampin, and 0.1-0.3 parts of anti-inflammatory factor. The surface bioactive coating is composed of the following components in parts by weight: 70-80 parts hyaluronic acid and 20-30 parts bioactive glass nanoparticles.

2. The three-layer intelligent dual-response nanomaterial artificial bone according to claim 1, characterized in that, The number-average molecular weight of the polycaprolactone is 80,000-120,000.

3. The three-layer intelligent dual-response nanomaterial artificial bone according to claim 1, characterized in that, The core support layer has a porosity of 60%-70% and a pore size of 200-500μm.

4. The three-layer intelligent dual-response nanomaterial artificial bone according to claim 1, characterized in that, The molar ratio of poly(2-dimethylaminoethyl methacrylate) to polyglutamic acid in the poly(2-dimethylaminoethyl methacrylate)-b-polyglutamic acid is 2.8-3.2:

1.

5. The three-layer intelligent dual-response nanomaterial artificial bone according to claim 1, characterized in that, The rifampicin content in the nanomicelles is 5-8% by weight; the anti-inflammatory factor is transforming growth factor-β, which accounts for 0.1-0.3% by weight in the nanomicelles.

6. The three-layer intelligent dual-response nanomaterial artificial bone according to claim 1, characterized in that, The thickness of the surface bioactive coating is 50-100 nm.

7. A method for preparing a three-layer intelligent dual-response nanomaterial artificial bone, the method being used to prepare the three-layer intelligent dual-response nanomaterial artificial bone according to any one of claims 1-6, characterized in that, The preparation method includes: (1) Preparation of core support layer: Weigh 55-67 parts of polycaprolactone, 30-40 parts of tricalcium α-phosphate and 3-5 parts of magnesium hydroxide by weight, add a mixed solvent composed of acetone and N-methylpyrrolidone, wherein the volume ratio of acetone to N-methylpyrrolidone in the mixed solvent is 3.8-4.2:1, stir until completely dissolved to form a printing slurry with a solid content of 25%-30%; use an ultra-low temperature 3D printer to print a porous scaffold green body, wherein the 3D printing temperature is -10℃ to -5℃, the nozzle diameter is 0.18-0.22mm, the layer thickness is 0.13-0.17mm, and the printing speed is 4.5-5.5mm / s; freeze-dry the porous scaffold green body at a temperature of -55℃ to -45℃ and a vacuum degree of 8-12Pa for 22-26h, and then anneal it in a vacuum oven at 35-39℃ for 7-9h to obtain the core support layer; (2) Preparation of nanomicelles: Weigh 95-105 parts of poly(2-dimethylaminoethyl methacrylate)-b-polyglutamic acid according to the weight ratio and dissolve it in deionized water to prepare a polymer solution with a concentration of 9-11 mg / mL; add 5-8 parts of rifampicin and 0.1-0.3 parts of transforming growth factor-β to the polymer solution, and ultrasonically disperse it for 8-12 min under the power of 280-320W. Then stir it in a water bath at 36-38℃ for 1.8-2.2 h. The nanomicelles prepared have a particle size of 80-120 nm and a particle size distribution index of 0.15-0.

20. (3) Drug-loaded layer: The core support layer is placed in the nanomicelle solution prepared in step (2) and vacuum impregnated for 3.5-4.5 h under vacuum conditions of 45-55 Pa and 23-27 °C. Then, it is freeze-dried for 10-14 h under conditions of -45 °C to -35 °C and vacuum conditions of 13-17 Pa to obtain a scaffold with a drug-loaded layer. (4) Coating: Weigh 70-80 parts of hyaluronic acid and 20-30 parts of bioactive glass nanoparticles by weight, add a sodium hydroxide solution with a concentration of 0.8%-1.2%, and ultrasonically disperse for 13-17 minutes under a power of 380-420W to form a coating solution with a concentration of 4.5-5.5 mg / mL; immerse the drug-loaded scaffold in the coating solution and coat it by lifting at a speed of 4.5-5.5 mm / s, and dry it at 35-39℃ for 5-7 hours, repeating the coating 2-3 times; then place the coated scaffold in a carbodiimide vapor with a concentration of 2.3%-2.7% for crosslinking treatment for 1.8-2.2 hours, and finally obtain a three-layer structure intelligent dual-response nanomaterial artificial bone.

8. The method for preparing a three-layer intelligent dual-response nanomaterial artificial bone according to claim 7, characterized in that, The magnesium hydroxide in step (1) has an average particle size of 50-100 nm and a purity of ≥99.5%.

9. The method for preparing a three-layer intelligent dual-response nanomaterial artificial bone according to claim 7, characterized in that, The printing path of the ultra-low temperature 3D printer in step (1) adopts an orthogonal grid structure with a grid spacing of 200-400μm.

10. The method for preparing a three-layer intelligent dual-response nanomaterial artificial bone according to claim 7, characterized in that, The adhesion between the bioactive coating formed in step (4) and the scaffold is 5-7 MPa.

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