High-compatibility bioactive glass composite material and preparation method thereof

Abstract

The invention relates to the technical field of medical composite materials, in particular to a high-compatibility bioactive glass composite material and a preparation method thereof. The preparation method comprises the following steps: synthesizing Mg / Sr-doped hydroxyapatite nano-powder and Zn / Li-doped bioactive glass microspheres, blending the Mg / Sr-doped hydroxyapatite nano-powder and the Zn / Li-doped bioactive glass microspheres with polycaprolactone, and preparing a stent primary blank with gradient pores which are dense outside and sparse inside through a low-temperature deposition 3D printing technology; and by taking the primary blank as a receiving device and adopting a coaxial electrostatic spinning technology, constructing a core-shell structure nanofiber functional layer loaded with the BMP-2 growth factor on the surface and in internal pores of the primary blank in situ. By regulating and controlling the composition of the bioactive glass and introducing functional metal ions, local alkaline stimulation caused by rapid release of ions after the material is implanted is reduced, and meanwhile, by combining a multi-gradient composite structure design and controllable loading of growth factors, synergistic improvement of biocompatibility, bioactivity and mechanical support performance of the composite material is realized; the bone regeneration can be effectively promoted, the stress damage is reduced, and the method is suitable for bone defect repair.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical composite materials, in particular to a high-compatibility bioactive glass composite material and a preparation method thereof. BACKGROUND

[0002] Hydroxyapatite (HA) is the main inorganic component of human bone, and is widely used in orthopedic and dental repair fields due to its excellent biocompatibility and bone conduction. However, the traditional pure HA material has high brittleness and poor toughness, and is not matched with the mechanical properties of natural bone tissue, and is prone to fracture. Moreover, the degradation of the material is slow, which may hinder the growth of new bone tissue.

[0003] Bioactive glass (BG) is a kind of functional material that can chemically combine with biological tissues and promote new bone formation. The classic representative of clinical application is 45S5 bioactive glass, which is composed of SiO2-CaO-Na2O-P2O5. After being implanted into the body, it can form a hydroxyapatite-like layer in contact with body fluids, promote bone cell adhesion, growth and bone integration, and achieve bone repair effect. It is an important material for bone tissue engineering and has been used for bone defect filling, bone transplantation surgery and dental implant scaffolds.

[0004] Although 45S5 bioactive glass has good bioactivity in bone regeneration, it still has the limitation of insufficient biocompatibility in clinical application. On the one hand, the release of ions causes a local high-alkaline environment, which brings biological stimulation problems. On the other hand, the mechanical properties are insufficient and the brittleness is high, which makes it difficult to be used as an independent implant body to bear large stress.

[0005] To improve its performance, the prior art usually combines bioactive glass with biodegradable polymers (such as PLGA, PCL), or introduces active components (such as ions, growth factors) to enhance bioactivity. However, these methods still do not solve the key defects.

[0006] Therefore, there is an urgent need to develop a new composite material that has excellent biocompatibility, bioactivity and mechanical support performance. SUMMARY

[0007] The present application aims to provide a high-compatibility bioactive glass composite material and a preparation method thereof to solve the problems in the background art.

[0008] To achieve the above-mentioned purpose, on the one hand, the present application provides a high-compatibility bioactive glass composite material, which is a three-dimensional porous scaffold structure with a "core-shell" fiber network coating, comprising: Three-dimensional porous scaffold matrix: It is composed of biodegradable polymers, element-doped nano-hydroxyapatite and neutral bioactive glass microspheres through low-temperature 3D printing technology. The scaffold has a gradient pore structure from the outside to the inside. Bionic "core-shell" nanofiber coating: A nanofiber network formed on the surface and in the internal pores of the three-dimensional porous scaffold matrix through coaxial electrospinning technology, wherein the "sheath" of the fiber is a biodegradable polymer loaded with element-doped nano-hydroxyapatite, and the "core" is a biodegradable polymer loaded with bone morphogenetic protein-2.

[0009] Preferably, the element-doped nano-hydroxyapatite is magnesium (Mg) and strontium (Sr) co-doped hydroxyapatite (Mg / Sr-HA), wherein the molar percentage of Mg doping is 5%-10% and the molar percentage of Sr doping is 5%-10%. 2+ Doping with Sr can regulate the crystallinity and degradation rate of HA and promote early osteoogenesis; 2+ Doping can enhance the osteoconductivity of materials and inhibit osteoclast activity.

[0010] Preferably, the neutral bioactive glass microspheres are zinc (Zn) and lithium (Li) co-doped bioactive glass microspheres (Zn / Li-NBG), maintaining the pH of the degradation solution in the neutral range (6.5-7.5). 2+ Li imparts antibacterial and angiogenesis-promoting properties to the material. + It can activate the Wnt / β-catenin signaling pathway to promote osteogenic differentiation.

[0011] Preferably, the neutral bioactive glass microspheres contain little or no Na2O (<2wt%).

[0012] Preferably, the biodegradable polymer is selected from at least one of polylactic acid-glycolic acid copolymer, polycaprolactone, and polylactic acid.

[0013] Preferably, in the three-dimensional porous scaffold matrix, the mass ratio of biodegradable polymer, Mg / Sr-HA, and Zn / Li-NBG microspheres is (50-70):(20-35):(10-15).

[0014] On the other hand, the present invention provides a method for preparing the above-mentioned highly compatible bioactive glass composite material, comprising the following steps: S1. Preparation of active components: Mg / Sr co-doped nano-hydroxyapatite (Mg / Sr-HA) was prepared by hydrothermal method or co-precipitation method; Zn / Li co-doped neutral bioactive glass microspheres (Zn / Li-NBG) were prepared by sol-gel method combined with spray drying. S2. Preparation of 3D printing slurry: Dissolve biodegradable polymer in an organic solvent, add Mg / Sr-HA nanopowder and Zn / Li-NBG microspheres prepared in step S1, and obtain a uniform composite printing slurry by ball milling or high-speed homogenization. S3, Low-temperature 3D printing scaffold preform: The slurry obtained in S2 is loaded into the barrel of a low-temperature deposition 3D printer. Based on the preset bone defect model, a three-dimensional porous scaffold preform with a gradient pore structure is printed and then freeze-dried. S4. In-situ electrospinning to construct nanofiber coatings: The three-dimensional porous scaffold preform obtained in S3 was used as a receiving device and placed in a coaxial electrospinning apparatus; two spinning solutions were prepared respectively: Solution A is a biodegradable polymer solution containing bone morphogenetic protein-2 (BMP-2), which is used as the core layer spinning solution; Solution B is a biodegradable polymer solution containing Mg / Sr-HA nanoparticles, used as the sheath spinning solution. Coaxial electrospinning is performed to uniformly deposit a "core-shell" structured nanofiber network on the surface and pore walls of the scaffold preform. S5. Post-processing: The composite scaffold obtained in S4 is subjected to secondary freeze-drying to remove residual solvent, and then sterilized by low-temperature plasma to obtain the final product.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: In this highly compatible bioactive glass composite material and its preparation method, the elastic modulus of the composite material can be finely controlled within a wide range (from a few MPa to a few GPa) by selecting the polymer matrix, designing the gradient pore structure, and introducing a flexible nanofiber layer on the surface, making it closer to human cancellous bone and effectively avoiding stress shielding effects. The nanofiber network can play a stress buffering role at the interface between the material and bone tissue.

[0016] This invention introduces different functional elements into bioactive glass composite materials to prepare low-sodium / sodium-free bioactive glass. Classical 45S5 bioactive glass has a high sodium ion content, and upon contact with liquid, sodium ions are readily released, causing a rapid increase in local pH, which can trigger cell stimulation and even local tissue necrosis. This invention effectively alleviates the formation of a local alkaline environment by designing an elementally stable glass network structure, reducing the rapid dissolution of sodium ions, and regulating ion release kinetics.

[0017] This invention programs different active components through a multi-level structure. In the early stages of implantation, Mg / Sr-HA and Zn / Li-NBG in the scaffold matrix first release Mg. 2+ 、Sr 2+ Zn 2+ Li +The active ions provide initial osteoconduction, antibacterial properties, and early osteogenic stimulation. Subsequently, as the nanofiber "sheath" degrades, more active ions are released. Finally, in the mid-to-late stages of repair, BMP-2 in the nanofiber "core" is slowly and continuously released, exerting a powerful osteoinductive effect. This active release mode, where ion release precedes growth factor release, highly mimics the physiological process of natural bone healing.

[0018] The overall degradation behavior of the material is dominated by the polymer matrix, while Mg doping accelerates the initial degradation of the HA phase, creating space for cell migration and new tissue ingrowth in advance; the intermediate degradation of NBG microspheres further provides biological signals; this multiphase degradation characteristic allows the mass loss of the material to be better matched with the ingrowth of new bone tissue in time and space.

[0019] The preparation method of this invention is both flexible and scalable. It can produce precisely shaped personalized 3D printed implants for the repair of large bone defects. Alternatively, the prepared composite powder can be mixed with a thermosensitive hydrogel (such as chitosan / sodium β-glycerophosphate) to make an injectable "bone repair clay" suitable for minimally invasive surgery or filling irregular bone defects.

[0020] The in-situ composite electrospinning technology used allows the nanofiber layer to grow directly on the pre-formed 3D printed scaffold. The two are tightly bonded, avoiding the interface separation problem that may be caused by secondary composite, and improving the integrity and stability of the structure. Attached Figure Description

[0021] Figure 1 This is an overall flowchart of Embodiment 1 of the present invention. Detailed Implementation

[0022] The technical solutions in 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.

[0023] Example 1: This embodiment of the invention provides a highly compatible bioactive glass composite material for a 3D-printed scaffold for bone defect repair. The preparation steps are as follows (see...). Figure 1 ): Step 1: Preparation of active components Preparation of Mg / Sr co-doped nano-hydroxyapatite (Mg / Sr-HA): With a molar ratio of Ca:(P+Mg+Sr) = 1.67, calcium nitrate, diammonium hydrogen phosphate, magnesium nitrate, and strontium nitrate were weighed out; Mg accounted for 8% of the total molar number of cations, and Sr accounted for 7%. The calcium and magnesium / strontium salts were dissolved in deionized water, and the phosphate was dissolved in another portion of deionized water. The pH was adjusted to 10⁻¹¹ with ammonia. Under vigorous stirring, the phosphate solution was slowly added dropwise to the mixed cation solution, and the reaction was carried out in a 60°C water bath for 24 hours. After the reaction, the precipitate was collected by centrifugation, washed repeatedly with deionized water and ethanol, dried under vacuum at 70°C, and ground to obtain Mg / Sr-HA nanoparticles. XRD and EDS characterization confirmed that it was doped with HA, with an average particle size of approximately 80 nm.

[0024] Preparation of Zn / Li co-doped neutral bioactive glass microspheres (Zn / Li-NBG): The formulation was designed according to the mass percentages (SiO2: 58%, CaO: 33%, P2O5: 4%, ZnO: 3%, Li2O: 2%), using tetraethyl orthosilicate, calcium nitrate, triethyl phosphate, zinc acetate, and lithium acetate as precursors. The precursors were dissolved in an ethanol-water-dilute nitric acid mixture and hydrolyzed at 40°C for 24 hours to form a sol. The sol was spray-dried (inlet temperature 180°C, outlet temperature 90°C) to obtain glass microspheres with a particle size of 5-20 μm. The microspheres were then heat-treated at 650°C for 2 hours (heating rate 1°C / min) to obtain crystalline Zn / Li-NBG microspheres. pH immersion tests showed that the solution pH remained at 7.1±0.2 after immersion in SBF for 7 days.

[0025] Step 2: Preparation of 3D printing paste and printing 3g of polycaprolactone (PCL, Mn=80kDa) was dissolved in 20mL of dichloromethane; 1.5g of Mg / Sr-HA nanoparticles and 0.5g of Zn / Li-NBG microspheres prepared in step one were added to the above solution and ball-milled for 4 hours using a planetary ball mill (300 rpm) to obtain a uniform composite slurry.

[0026] The slurry was loaded into the barrel of a low-temperature deposition 3D printer, and the printing parameters were set as follows: nozzle diameter 0.3 mm, printing platform temperature -30℃. Based on the 3D model reconstructed from Micro-CT data of rabbit tibial defects, a cylindrical scaffold with a diameter of 5 mm and a height of 10 mm was designed and printed. To simulate the density change of natural cancellous bone from the outside to the inside and to optimize mechanical support and cell ingrowth, the outer region (outer 1 mm) was designed to have a porosity of 50% and a pore size of 300 μm; the inner region had a porosity of 70% and a pore size of 500 μm. After printing, the scaffold embryo was freeze-dried at -50℃ for 24 hours to obtain the scaffold embryo.

[0027] Step 3: In-situ electrospinning to construct a "core-shell" nanofiber coating Preparation of spinning solution: Core layer solution (solution A): Dissolve 50 mg of recombinant human BMP-2 in 1 mL of deionized water, and dissolve 400 mg of PLGA (LA:GA=75:25) in 4 mL of hexafluoroisopropanol (HFIP). Mix the two solutions and stir gently for 2 hours.

[0028] Sheath fluid (solution B): Disperse 200 mg Mg / Sr-HA nanoparticles in 5 mL HFIP and sonicate for 30 minutes. Add 800 mg PCL and stir until completely dissolved.

[0029] The preform of the support obtained in step two is fixed on a self-made rotating receiving device (rotation speed 100 rpm) and placed directly in front of the nozzle of the coaxial electrospinning equipment.

[0030] Set up a coaxial nozzle with an inner diameter (core layer) of 0.4 mm and an outer diameter (sheath layer) of 1.2 mm. Inject liquid A and liquid B into the corresponding syringe pumps respectively.

[0031] Electrospinning parameters were set as follows: voltage 18 kV, core liquid propulsion speed 0.3 mL / h, sheath liquid propulsion speed 0.8 mL / h, receiving distance 15 cm, ambient humidity <40%, and spinning time 2 hours.

[0032] After spinning, the composite material is placed in a vacuum drying oven and dried for 48 hours to completely remove residual solvent.

[0033] Step 4: Post-processing The dried composite material was placed in a low-temperature plasma cleaner, using argon as the treatment gas, with a power of 100W and a treatment time of 5 minutes, to perform surface hydrophilic modification and sterilization.

[0034] Example 2: Preparation of injectable bone repair "clay", the preparation steps are as follows: Step 1: Preparation of composite microsphere powder Mg / Sr-HA nanopowder and Zn / Li-NBG microspheres were prepared according to step one of Example 1.

[0035] Composite microspheres were prepared using an emulsification-solvent evaporation method: 1 g of PLGA (50:50) and 0.4 g of Mg / Sr-HA were dissolved in 10 mL of dichloromethane as the oil phase; 0.1 g of Zn / Li-NBG microspheres and 5 mg of BMP-2 were dispersed in 100 mL of an aqueous phase containing 2% PVA; the oil phase was poured into the aqueous phase under high-speed shear (8000 rpm), emulsified for 5 minutes, and then slowly stirred at room temperature for 6 hours to allow solvent evaporation. The microspheres were collected by centrifugation and freeze-dried to obtain composite microsphere powder loaded with multiple active components, with a particle size range of 20-100 μm.

[0036] Step Two: Prepare Injectable "Clay" Preparation of the thermosensitive hydrogel prepolymer: Dissolve 2.5 g of chitosan (85% deacetylation) in 100 mL of 0.1 M hydrochloric acid solution; separately dissolve 5.6 g of sodium β-glycerophosphate in 20 mL of deionized water. Mix the two solutions thoroughly in an ice bath and adjust the pH to 7.2 to obtain a clear solution.

[0037] The composite microsphere powder obtained in step one was added to the above hydrogel prepolymer at a ratio of 20% (w / v), and stirred and mixed evenly at 4°C to obtain a gray, "clay"-like composite material with good flowability.

[0038] Experimental Example 1: pH changes in leachates from the conventional 45S5 group, the bioactive glass composite material group (containing sodium), and the bioactive glass composite material group (without sodium). The purpose of this experiment is to verify that by controlling the sodium content in bioactive glass and introducing Zn / Li / Mg / Sr doped neutral bioactive glass, the problem of local alkalinity increase caused by rapid ion release in body fluid environment of traditional 45S5 bioactive glass can be effectively alleviated, thereby improving the biocompatibility of the material.

[0039] Test materials Experimental Example 1A: Bioactive glass composite material (Na-free) was prepared using the method of Example 1. Comparative Example 1A: A bioactive glass composite material containing 5 wt% Na2O was prepared using the method of Example 1. Comparative Example 1B: Conventional 45S5 bioactive glass, with a composition of 45% SiO2, 24.5% CaO, 24.5% Na2O, and 6% P2O5. Test methods The material extract was prepared with a solid-liquid ratio of 0.2 g / mL. The extraction medium was PBS buffer solution (initial pH = 7.40 ± 0.05). The extract was soaked at a constant temperature of 37℃ for 30 hours, and the pH value of the extract at different time points was measured using a pH meter. The results are shown in Table 1.

[0040] Table 1. Changes in pH value of leachate from different materials over time. As shown in Table 1, the conventional 45S5 bioactive glass in Comparative Example 1B caused a rapid increase in solution pH in the initial soaking stage, exceeding 9.0 within 6 hours, forming a distinctly alkaline environment, which remained above 9.0 for up to 30 hours. The composite material containing trace amounts of sodium in Comparative Example 1A reduced the alkalization rate to some extent, but the pH increased to 8.10 within 30 hours.

[0041] The solution pH of the bioactive glass composite material of this invention remained within the range of 7.4–7.7 throughout the entire test period, without any obvious alkalization phenomenon. This indicates that the introduction of Zn / Li / Mg / Sr doping and the removal of Na can significantly reduce the alkaline stimulation caused by rapid ion release.

[0042] Experimental Example 2: Safety Verification of Bioactive Glass Composite Material Group (Cytotoxicity, Sensitization, Irritation, Acute Toxicity) This test case is used to verify whether the bioactive glass composite material of the present invention meets the relevant biosafety requirements under the corresponding application conditions of implantation and injection.

[0043] Test materials Experimental Example 2A: Using the method of Example 1, an implantable bioactive glass composite material was prepared, and an extract was prepared by shaking and extracting at 37°C and 60 rpm / min for 24 hours for in vitro cytotoxicity detection; an extract was prepared by shaking and extracting at 37°C and 60 rpm / min for 72 hours for skin sensitization, intradermal irritation, and acute systemic toxicity detection.

[0044] Experimental Example 2B: Using the method of Example 2, an injectable bioactive glass composite material was prepared, and an extract was prepared by shaking and extracting at 37°C and 60 rpm / min for 24 hours for in vitro cytotoxicity testing; an extract was prepared by shaking and extracting at 37°C and 60 rpm / min for 72 hours for skin sensitization, intradermal irritation, and acute systemic toxicity testing.

[0045] Experimental items and methods In vitro cytotoxicity assay: The cytotoxicity of the materials was evaluated using an extract assay. 24-hour extracts from Experiment 2A and Experiment 2B were taken and added to culture wells inoculated with L929 cells (or diluted down to four concentration gradients), and cultured simultaneously with the control culture group. After 24 hours of culture, cell metabolic activity was quantitatively measured using a MTT assay, and cell viability was calculated to evaluate the effect of the material extract on cell growth and proliferation.

[0046] Skin sensitization test: 72-hour extracts (bipolar) from Test Example 2A and Test Example 2B were used to sensitize the experimental animals multiple times, followed by a challenge test. The appearance of allergic reactions such as erythema and edema on the animal's skin was observed and recorded.

[0047] Intradermal irritation test: 72-hour extracts (bipolar) from Experiment 2A and Experiment 2B were injected intradermally into the experimental animals, with physiological saline / cottonseed oil as a control. Erythema, edema, and other reactions at the injection site were observed at different time points after injection, and the degree of irritation was scored to evaluate the material's irritant effect on local tissues.

[0048] Acute systemic toxicity test: Extracts from test case 2A and test case 2B were injected into the experimental animals, and the animals' mental state, behavioral changes, weight changes and survival were continuously observed.

[0049] The test results are shown in Table 2. Table 2 Biosafety Evaluation Results According to the test results shown in Table 2, the bioactive glass composite material of the present invention did not exhibit obvious cytotoxicity, sensitization, irritation or acute systemic toxicity, and meets the requirements for biosafety of implantable and injectable bone repair materials.

[0050] Experimental Example 3: Effects of Gradient Pore Structure and Surface Nanocoating on Mechanical Adaptability and Cell Growth The purpose of this experiment is to verify whether the combination of a gradient pore structure with a "dense outer layer and sparse inner layer" and a surface coaxial electrospun nanofiber coating can optimize the mechanical properties of the composite scaffold (making it more compatible with human bone tissue) and significantly promote the three-dimensional migration and adhesion of cells within the scaffold.

[0051] Experimental materials: Experimental Example 3A (Invention Group): Using the method of Example 1, a 3D printed scaffold with a gradient pore structure was prepared (outer region: porosity 50%, pore size 300μm; inner region: porosity 70%, pore size 500μm), and it was subjected to coaxial electrospinning treatment to form a core-shell nanofiber coating loaded with BMP-2 on the surface.

[0052] Comparative Example 3A (homogeneous structure control): The material composition and surface coating were exactly the same as those of Experimental Example 3A, but the 3D printed structure was a single homogeneous pore (overall porosity of 60%, pore size ~400μm).

[0053] Comparative Example 3B (Uncoated Control): A scaffold preform with the same gradient pore structure as Example 3A was prepared, but without any surface nanofiber coating treatment.

[0054] Test method: Mechanical property testing: A universal testing machine was used to perform compression tests on 5 samples in each group (sample size was a cylinder with a height of 10 mm and a diameter of 5 mm). The loading rate was set to 1 mm / min, and pressure was applied along the long axis of the specimen. During the process, the specimen was moistened with physiological saline until it ruptured. The loading was then stopped, the compression modulus was calculated, and the fracture behavior was observed.

[0055] In vitro three-dimensional cell ingrowth experiment: Human bone marrow mesenchymal stem cells (hBMSCs) were seeded into each group of scaffolds and cultured for 14 days. The penetration depth and spatial distribution of cells inside the scaffolds were quantitatively analyzed by fluorescence staining and Z-axis scanning with laser confocal microscopy.

[0056] The results are shown in Table 3.

[0057] Table 3 According to Table 3, the compressive modulus (650 MPa) of Experimental Example 3A is closest to that of human cancellous bone (~500 MPa), achieving the best mechanical fit; Comparative Example 3A has an excessively high modulus due to its homogeneous structure; Although Comparative Example 3B has a gradient structure, it lacks the toughening effect of the flexible nanofiber coating, and its modulus is still too high and it exhibits more brittle characteristics when fractured.

[0058] The gradient pore structure (Experimental Example 3A) itself facilitates nutrient diffusion and cell inward migration. However, the surface nanofiber coating (Experimental Example 3A) greatly improves the initial adhesion and spreading of cells on the material surface, thereby achieving the deepest and most uniform three-dimensional cell distribution.

[0059] Experiment Example 4: Validation of Controllable Degradation Behavior and Dual Biological Functions of Antibacterial / Angiogenic Properties The purpose of this experiment is to verify whether a controllable degradation rate matching bone growth can be achieved through multiphase composite design, while simultaneously using dopant ions (Zn2+) to endow the material with additional biological functions such as antibacterial and angiogenesis promotion.

[0060] Experimental materials: Test Example 4A (Standard Group of this Invention): Standard Composite Material (PCL Matrix + Mg / Sr-HA + Zn / Li-NBG).

[0061] Comparative Example 4A (Fast Degradation Group): PLGA (50:50), which has a faster degradation rate, was used to completely replace PCL as the matrix and fiber material.

[0062] Comparative Example 4B (Non-functional Ion Group): Pure HA (undoped Mg / Sr) and undoped Zn NBG were used as controls for functional ion deficiency.

[0063] Test method: In vitro degradation: The sample was immersed in enzyme-containing PBS for 12 weeks, and the mass loss rate and solution pH were measured periodically.

[0064] Antibacterial properties: After co-culturing with Staphylococcus aureus for 24 hours, the inhibition rate was calculated by colony counting.

[0065] Promoting angiogenesis: The chicken embryo allantoic membrane (CAM) assay was used to evaluate the promoting effect of the material extract on angiogenesis. The results are shown in Table 4.

[0066] Table 4 As shown in Table 4, Experimental Example 4A exhibited a moderate and controllable degradation rate (approximately 28% loss after 12 weeks), which best matched the ideal rate of new bone growth; Comparative Example 4A suffered premature structural collapse due to rapid degradation of PLGA; and Comparative Example 4B degraded too slowly due to the bioinertness of the material.

[0067] Antibacterial function: Test Example 4A and Comparative Example 4A contain Zn 2+ All of them exhibited extremely strong antibacterial properties, while the comparative example 4B (Zn-free) showed significantly better antibacterial performance. 2+ (The following is a list of related functions, which is not available in the original text.)

[0068] Promoting vascular function: The extract of Experiment 4A showed a significant pro-angiogenic ability, mainly attributed to Zn. 2+ / Li + Release. Comparative example 4B does not have this function.

[0069] Experimental Example 5: In vitro synergistic osteogenic effect of sequential release of multi-level active ions and growth factors The purpose of this experiment is to investigate the release of Mg from Mg / Sr-HA. 2+ 、Sr 2+ Zn released by Zn / Li-NBG 2+ Li + The question is whether the three—including BMP-2, which is released slowly from the core-shell fibers—can form a sequential relationship over time and produce a synergistic effect, thus significantly outperforming single or traditional active components.

[0070] Experimental materials: Experimental Example 5A (Complete System of the Invention): A complete composite material comprising Mg / Sr-HA, Zn / Li-NBG and BMP-2 core-shell fibers.

[0071] Comparative Example 5A (Ionic Active Group Only): The material contains only Mg / Sr-HA and Zn / Li-NBG, and the electrospinning layer is pure PCL fiber without BMP-2.

[0072] Comparative Example 5B (Growth Factor Group Only): The matrix was pure PCL (without any active ceramics), but the electrospinning layer was a core-shell fiber loaded with BMP-2.

[0073] Comparative Example 5C (Conventional Materials Group): The Zn / Li-NBG in Experimental Example 5A was replaced with an equal amount of classic 45S5 bioglass powder.

[0074] Test method: Release kinetics: The concentrations of various ions and the content of BMP-2 in simulated body fluids were detected at different time points.

[0075] Osteogenic differentiation assessment: Alkaline phosphatase (ALP) activity was measured on day 7 in co-culture with hBMSCs; osteogenic-related gene (Runx2, OPN) expression was detected by qPCR on day 14; and calcium nodule deposition was semi-quantitatively analyzed by Alizarin Red (ARS) staining on day 21. Results are shown in Table 5.

[0076] Table 5 As shown in Table 5, Experimental Example 5A significantly outperformed any single active component or conventional material in all osteogenic parameters (early ALP activity, mid-term gene expression, and late-term mineralization). This demonstrates that multi-level active components (short-term ion release and long-term growth factor release) can produce significant biological effects.

[0077] Experimental Example 6: Efficacy verification of the implantable type of the present invention (compared to the traditional 45S5 group) and the injectable type of the present invention (compared to the blank hydrogel group), repair efficacy in a rat skull defect model: bone density increase and trabecular bone number increase (significant effect at 12 weeks). The purpose of this experiment is to verify the actual effect of implantable and injectable bioactive glass composite materials developed based on the technical platform of this invention in the repair of bone defects in vivo, and to compare them with traditional 45S5 bioactive glass and blank materials.

[0078] Animal Model and Grouping: Healthy male SD rats (weighing 250–280 g) were used to create a critical-size defect model with a diameter of 5 mm in the skull. Eight animals were grouped in each group as follows: Experimental Example 6A (Implantable type of the present invention): An implantable bioactive glass composite material was prepared according to Example 1.

[0079] Comparative Example 6A (Traditional 45S5 Group): Traditional 45S5 bioactive glass powder with a ratio of 45% SiO2, 24.5% CaO, 24.5% Na2O, and 6% P2O5.

[0080] Experimental Example 6B (Injectable type of the present invention): Injectable thermosensitive composite "bone repair clay" (containing Mg / Sr-HA and Zn / Li-NBG active microspheres) prepared according to Example 2.

[0081] Comparative Example 6B (blank hydrogel): Only chitosan / β-glycerophosphate sodium thermosensitive hydrogel was used, without any active ingredients.

[0082] Test method: Six and twelve weeks after bone defect filling, the defect area was reconstructed in three dimensions using Micro-CT, and the following indicators were quantitatively analyzed: bone volume fraction (Bone Volume / Tissue Volume, BV / TV, %), i.e., the proportion of mineralized bone volume to the total volume, and the number of trabeculae (Tb.N, 1 / mm). The results are shown in Table 6.

[0083] Table 6 Comparison of cranial defect repair effects in rats (6 weeks and 12 weeks) As shown in Table 6, the implantable and injectable composite materials of this invention exhibited significantly better bone repair effects than the control group at 12 weeks post-operation, with significantly higher bone tissue volume ratio and trabecular bone number compared to the traditional 45S5 bioactive glass and blank hydrogel groups. The implantable material showed better repair performance under mechanical support conditions; the injectable material also demonstrated excellent bone defect repair capabilities and better operational convenience in complex or irregular defects, validating its broad clinical translation prospects.

[0084] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A highly compatible bioactive glass composite material, characterized in that, The composite material is a three-dimensional porous scaffold structure with a core-shell fiber network coating, which comprises: a three-dimensional porous scaffold matrix: a biodegradable polymer, element-doped nano-hydroxyapatite and neutral bioactive glass microspheres are compounded by low-temperature 3D printing technology, and the three-dimensional porous scaffold matrix has a gradient pore structure from outside to inside; a biomimetic core-shell nanofiber coating: a nanofiber network formed on the surface and inside pores of the three-dimensional porous scaffold matrix by coaxial electrospinning technology, wherein the sheath layer of the fiber is a biodegradable polymer loaded with element-doped nano-hydroxyapatite, and the core layer is a biodegradable polymer loaded with bone morphogenetic protein-2.

2. The highly compatible bioactive glass composite material of claim 1, wherein, The element-doped nano-hydroxyapatite is magnesium and strontium co-doped hydroxyapatite, wherein the doping molar percentage of magnesium is 5%-10%, and the doping molar percentage of strontium is 5%-10%.

3. The highly compatible bioactive glass composite material of claim 1, wherein, The neutral bioactive glass microspheres are zinc and lithium co-doped bioactive glass microspheres, and the composition does not contain Na2O.

4. The highly compatible bioactive glass composite material of claim 1, wherein, The biodegradable polymer is selected from at least one of polylactic acid-glycolic acid copolymer, polycaprolactone and polylactic acid.

5. The highly compatible bioactive glass composite material of claim 1, wherein, In the three-dimensional porous scaffold matrix, the mass ratio of biodegradable polymer, magnesium / strontium co-doped nano-hydroxyapatite and zinc / lithium co-doped neutral bioactive glass microspheres is 50-70:20-35:10-15.

6. A method for the preparation of the highly compatible bioactive glass composite material according to any one of claims 1 to 5, characterized in that, It comprises the following steps: S1, preparing active components: preparing magnesium / strontium co-doped nano-hydroxyapatite, and preparing zinc / lithium co-doped neutral bioactive glass microspheres; S2, preparing 3D printing slurry: dissolving biodegradable polymer in organic solvent, adding magnesium / strontium co-doped nano-hydroxyapatite and zinc / lithium co-doped neutral bioactive glass microspheres prepared in S1, ball milling or high-speed homogenization to obtain uniform composite printing slurry; S3, low-temperature 3D printing scaffold embryo: loading the slurry obtained in S2 into the barrel of a low-temperature 3D printer, printing a three-dimensional porous scaffold embryo with a gradient pore structure according to a preset bone defect model, and then freeze-drying; S4, in-situ electrospinning to construct nanofiber coating: using the three-dimensional porous scaffold embryo obtained in S3 as a receiving device, performing coaxial electrospinning; wherein the core layer spinning solution is a biodegradable polymer solution containing bone morphogenetic protein-2, and the sheath layer spinning solution is a biodegradable polymer solution containing magnesium / strontium co-doped nano-hydroxyapatite; uniformly depositing a core-shell structure nanofiber network on the surface and pore wall of the scaffold embryo; S5, post-processing: secondary freeze-drying of the composite scaffold obtained in S4 to remove residual solvent, and low-temperature plasma sterilization to obtain the final product.

7. The method of claim 6, wherein the high compatibility bioactive glass composite material is prepared by the steps of: In S1, the magnesium / strontium co-doped nano-hydroxyapatite is prepared by hydrothermal method or coprecipitation method; the zinc / lithium co-doped neutral bioactive glass microspheres are prepared by sol-gel method combined with spray drying.

8. The method of claim 6, wherein the high compatibility bioactive glass composite material is prepared by the steps of: In S3, the gradient pore structure is specifically: the porosity of the outer region is 50%, and the pore size is 300 μm; the porosity of the inner region is 70%, and the pore size is 500 μm.

9. The method for preparing the highly compatible bioactive glass composite material according to claim 6, characterized in that, In the S4, the process parameters of the coaxial electrospinning are as follows: Voltage: 15-20 kV, core layer spinning solution propelling speed: 0.2-0.4 mL / h, sheath layer spinning solution propelling speed: 0.6-1.0 mL / h, receiving distance: 10-20 cm.

10. The method for preparing the highly compatible bioactive glass composite material according to claim 6, characterized in that, The method further comprises the step of preparing an injectable composite material: The composite microsphere powder containing the magnesium / sodium co-doped nano-hydroxyapatite, the zinc / lithium co-doped neutral bioactive glass microspheres and the bone morphogenetic protein-2 is mixed with a temperature-sensitive hydrogel pre-polymer solution to obtain an injectable composite material.

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