Magnetoelectric stent for realizing bone repair under external field driving as well as preparation method and application of magnetoelectric stent

Abstract

The invention discloses a magnetoelectric stent for realizing bone repair under external field driving and a preparation method and application thereof.The stent comprises a stent body based on a triple-period minimal curved surface structure and a magnetoelectric nano-particle coating, and the stent body comprises a convoluted and / or through hole structure; and the magnetoelectric nanoparticle coating is loaded on the inner surface of at least part of the pore structure. The magnetoelectric stent is suitable for providing better mechanical support for the early stage of bone repair of large-area bone defects, meanwhile, under the synergistic effect of magnetoelectric stimulation, osteogenesis and angiogenesis coupling can be promoted, and bone defect repair under the complex conditions of oral clinical alveolar bone vertical bone increment and systemic diseases such as inflammation and the like is achieved.

Description

[0001] Cross-references to related applications This application claims priority to patent application No. CN202511648244.5, filed on November 12, 2025, entitled "A Magnetoelectric Scaffold for Bone Repair under External Field Drive, and its Preparation Method and Use Thereof", the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] This invention relates to the field of bone tissue regeneration engineering, specifically to a magnetoelectric scaffold for bone repair driven by an external field, its preparation method, and its applications. Background Technology

[0003] Complex bone defect repair is a significant challenge in orthopedics and oral and maxillofacial surgery, with two main types: vertical bone defects and borderline bone defects arising from systemic diseases (such as inflammation). Vertical bone augmentation is a highly challenging technique in dental implantology and maxillofacial surgery, aiming to restore vertical bone height without the closure of surrounding bone walls. The difficulties lie in the irregular shape of the defect, high tension in the surrounding soft tissues, limited blood supply, and poor stability. Bone defects arising from pathological conditions such as inflammation not only result in severe bone loss, but the pathological microenvironment further disrupts the osteogenic-osteoclastic balance through inflammatory factors, severely impairing local blood supply and hindering bone regeneration. To address these challenges, research suggests that ideal bone grafts should possess strong mechanical support and osteogenic and vascularizing properties. Current repair methods, such as GBR, bone grafting, and distraction osteogenesis, are not only technically sensitive but also frequently accompanied by complications such as collapse, membrane exposure, insufficient blood supply, and infection, leading to bone regeneration falling far short of expectations.

[0004] Given the irregular shapes of bone defects and the need for early blood supply, 3D-printed scaffolds with customizable shapes and pore structures offer a superior strategy for precise bone repair. However, for vertical bone defects and bone defects caused by complex conditions such as systemic diseases like inflammation, the mechanical properties of existing 3D-printed scaffolds still need further improvement. Furthermore, simply optimizing the scaffold structure and selecting scaffold printing pastes offers limited and singular methods for promoting osteogenic regeneration. There is an urgent need to develop a scaffold specifically designed for common and complex bone defects in clinical practice that provides strong mechanical support in the early stages of bone repair while exhibiting excellent osteogenic and angiogenic properties, thereby enhancing the promotion of in-situ bone regeneration. Summary of the Invention

[0005] To address at least some of the technical problems in the prior art, this invention provides a magnetoelectric scaffold for bone repair under external field drive, its preparation method, and its applications. Specifically, this invention includes the following:

[0006] In a first aspect, the present invention provides a magnetoelectric scaffold for bone repair under external field drive. The scaffold includes a scaffold body based on a triple-period minimal curved surface structure and a magnetoelectric nanoparticle coating. The scaffold body includes a spiral and / or through-hole structure. The magnetoelectric nanoparticle coating is loaded on at least a portion of the inner surface of the pore structure. The magnetoelectric nanoparticles include a shell structure with piezoelectric properties and a core structure with magnetoelectric response properties.

[0007] In some embodiments, the pore size of the pore structure is in the range of 100-500 μm, and the particle size of the magnetoelectric nanoparticles is 100-500 nm, thereby enabling the magnetoelectric nanoparticles to enter the interior of the pore structure and form a magnetoelectric nanoparticle layer on the inner surface.

[0008] In some embodiments, the scaffold body material may be selected from one or more of chitosan, gelatin, collagen, fibrin, elastin, alginate, polycaprolactone (PCL), polylactic acid (PLA), polylactic-glycolic acid (PLGA), polyetheretherketone (PEEK), hydroxyapatite (HA), tricalcium phosphate (TCP), calcium silicate, and bone cement, preferably tricalcium phosphate, more preferably β-tricalcium phosphate.

[0009] In some embodiments, the magnetoelectric nanoparticle coating comprises a polymer obtained by the polymerization of acidic monomers.

[0010] In some embodiments, the shell structure of the magnetoelectric nanoparticles is prepared from inorganic piezoelectric materials and / or organic piezoelectric materials, and the core structure of the magnetoelectric nanoparticles is prepared from magnetoelectric materials.

[0011] In some embodiments, the inorganic piezoelectric material is selected from at least one of ferrite, niobate, titanate, silicate, and aluminate materials; wherein the ferrite material has the following structure: M x Fe 2-x O y M includes at least one of Bi, Ca, Mg and Ba, where x is a number from 0.25 to 1.5 and y is 3.

[0012] The organic piezoelectric material is selected from at least one of polyvinylidene fluoride, polyester, polymethyl methacrylate, nylon, polyvinyl chloride, poly-L-lactide, poly(3-hydroxybutyrate-CO-3-hydroxyvalerate), vinylidene fluoride / trifluoroethylene copolymer, vinylidene fluoride / tetrafluoroethylene copolymer, polyvinylidene fluoride-hexafluoropropylene, and polydimethylsiloxane.

[0013] The chemical formula of the magnetoelectric material is: N a Fe 1-a O bWhere N represents at least one of Co, Mn, Zn and Ni, a is a number from 0.25 to 1.5, and b is 4.

[0014] In a second aspect, the present invention provides a method for preparing a magnetoelectric scaffold for bone repair under external field drive, comprising the following steps: (1) providing a magnetoelectric nanoparticle mother liquor, which comprises a polymer obtained by polymerization of acidic monomers, magnetoelectric nanoparticles and a solvent; and (2) placing a scaffold body based on a triple-period minimal surface structure into the magnetoelectric nanoparticle mother liquor for treatment, and then removing and drying it.

[0015] In some embodiments, the magnetoelectric nanoparticles account for 0.2%-3.5% of the weight of the mother liquor.

[0016] In some embodiments, the polymer obtained by the polymerization of the acidic monomer is 3-8% by weight of the mother liquor.

[0017] A third aspect of the present invention provides the use of a magnetoelectric scaffold for bone repair driven by an external field.

[0018] In some embodiments, the use is to promote osteogenic and angiogenic coupling and / or vertical bone mass growth.

[0019] A fourth aspect of the present invention provides a method for regulating in vitro cell phenotypes using an externally driven magnetoelectric scaffold.

[0020] The magnetoelectric scaffold of the present invention can form a specific coating structure without changing the pore structure of the TPMS scaffold. This not only improves the mechanical properties and provides better mechanical support for the early stage of bone repair in large-area bone defects, but also introduces external field synergistic regulation to generate surface potential, thereby applying magnetoelectric stimulation to surrounding cells, greatly promoting osteogenic and angiogenic coupling and vertical bone mass growth. Furthermore, it can be applied to the repair of bone defects under complex conditions such as systemic diseases like inflammation, such as pathological conditions. Attached Figure Description

[0021] Figure 1 The characterization of exemplary magnetoelectric particles of the present invention includes, where a is a SEM image, b is an EDS image, c is an XRD image, d is a VSM curve, e is a PFM image, and f is an Rh B decomposition test image.

[0022] Figure 2 Comparison of SEM images of TPMS scaffolds coated with 0% PLA, 1% PLA, 2% PLA, 5% PLA, and 10% PLA.

[0023] Figure 3 Comparison of EDS of magnetoelectric support TPMS coated with 0% and 5% PLA.

[0024] Figure 4 Experimental comparison of the effects of scaffolds loaded with 0%, 0.25%, 0.5%, 1%, 2%, 4%, and 8% magnetoelectric particle layers on cell viability.

[0025] Figure 5 Schematic diagram and characterization diagram of scaffold preparation, where a is schematic diagram, b is SEM image, c is XRD image, d is EDS image, e is VSM image, f is output voltage image, g is EPR image of hydroxyl radical and superoxide radical, h is Rh B decomposition test image, i is mechanical property test image, j is compressive strength, water contact angle and porosity image, and k is ICP ion release result.

[0026] Figure 6 Schematic diagram and results of cell proliferation and adhesion experiments, where a is a schematic diagram, b is a SEM image, c is a staining image of live and dead cells, d is a CCK8 cell culture image on scaffold, e is a BSA protein adhesion image, and f is an immunofluorescence staining image of adhesion spots.

[0027] Figure 7 Schematic diagram and results of in vitro osteogenic differentiation experiment, where a is a schematic diagram, b is osteogenic-related gene PCR, c is ALP staining, d is Alizarin Red staining, e is BMP-2 immunofluorescence, and f is OPN immunofluorescence.

[0028] Figure 8 Schematic diagram and results of in vitro angiogenesis experiment, where a is a schematic diagram, b is the result of Transwell experiment, c is the angiogenesis-related PCR image, d is the result of angiogenesis experiment, and e is the CD31 immunofluorescence image.

[0029] Figure 9 Schematic diagram and results of osteogenic experiment in rats, where a is a schematic diagram, b is a CT image of rat skull, c is a semi-quantitative CT analysis image, d is a CD31 / OPN immunofluorescence image, and e is an HE and Masson staining image.

[0030] Figure 10 Schematic diagram and results of osteogenic experiment in rats under inflammatory conditions, where a is a schematic diagram, b is a CT image of rat skull, c is a semi-quantitative CT analysis image, d is a CD31 / OPN immunofluorescence image, and e is an HE and Masson staining image.

[0031] Figure 11 Schematic diagram and results of osteogenesis experiment in beagle dogs, where a is a schematic diagram, b is a photograph of the surgical procedure, c is a CBCT image, d is a Micro-CT image, and e is a semi-quantitative analysis.

[0032] Figure 12The results of in vivo safety studies are shown in the figure, where a is the red blood cell hemolysis experiment and b is the visceral HE staining. Detailed Implementation

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0034] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that the upper and lower limits of the range and each intermediate value between them are specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0036] In a first aspect, the present invention provides a magnetoelectric scaffold for bone repair under external field drive. The scaffold comprises a scaffold body based on a triple-period minimal curved surface structure and a magnetoelectric nanoparticle coating. The scaffold body comprises a spiral and / or through-hole structure. The magnetoelectric nanoparticle coating is loaded on at least a portion of the inner surface of the pore structure. The magnetoelectric nanoparticles comprise a shell structure with piezoelectric properties and a core structure with magnetoelectric response properties.

[0037] In this invention, the "triple-periodic minimal surface structure" is a surface structure with periodic repetition in three-dimensional space and an average curvature of zero everywhere. It features smooth continuity, high specific surface area, and adjustable porosity. The type of triple-periodic minimal surface structure in this invention is not limited and can be a Schwarz Primitive structure (P-type), a Gyroid structure (G-type), a Diamond structure (D-type), a Schwarz I-WP structure (I-type), a Neovius structure (N-type), a Split-P structure (S-type), a Hybrid structure, and / or a hollow wall structure. This invention has found that, compared to other subtypes, the G-type has stronger fluid permeability, and its internal helical pores and through-pores are more conducive to vascularization. Therefore, the G-type Gyroid structure is preferred. On the other hand, due to the large pore size and high porosity of the Gyroid structure, its mechanical properties are poor and cannot meet the application scenarios of large-area bone defects. Therefore, the preferred solution of this invention provides a way to improve the strength of the G-type structure without affecting the pore size structure.

[0038] In this invention, the "support body" includes a porous structure, such as a spiral and / or through-hole structure. This porous structure is generated by a triple-period minimal surface. Those skilled in the art will understand that the pore size of this structure can be precisely controlled by adjusting the design parameters of the triple-period minimal surface. The pore size of the porous structure in this invention is 100-500 μm, preferably 200-400 μm, even more preferably 200-300 μm, further preferably 220-260 μm, and most preferably 220-240 μm, for example, 220, 222, 224, 226, 228, 230, 232, 234, 236, 238, and 240 μm.

[0039] In this invention, the "scaffold body material" can be one or more of polymeric materials and inorganic non-metallic materials. The polymeric material can be a natural polymeric material or an artificial polymeric material. Natural polymeric materials can include chitosan, gelatin, collagen, fibroin, elastin, alginate, etc. Artificial polymeric materials can include polycaprolactone (PCL), polylactic acid (PLA), polylactic-co-glycolic acid (PLGA), polyetheretherketone (PEEK), etc. Inorganic non-metallic materials can include hydroxyapatite (HA), tricalcium phosphate (TCP), calcium silicate, and bone cement, etc. In a preferred embodiment, the "scaffold body" material is tricalcium phosphate. In a more preferred embodiment, the "scaffold body material" is β-tricalcium phosphate.

[0040] In this invention, the magnetoelectric nanoparticles possess a piezoelectric shell structure, which is prepared from inorganic and / or organic piezoelectric materials. In a preferred embodiment, the piezoelectric shell structure is prepared from an inorganic piezoelectric material. In a more preferred embodiment, the inorganic piezoelectric material is selected from at least one of ferrites, niobates, titanates, silicates, and aluminates. In a most preferred embodiment, the piezoelectric shell structure is prepared from a ferrite material. In this invention, the ferrite material has the following structure: M x Fe 2-x O y M includes at least one of Bi, Ca, Mg and Ba, where x is a number from 0.25 to 1.5 and y is 3.

[0041] In this invention, the magnetoelectric nanoparticles possess a core structure with magnetoelectric response properties. This core structure is prepared from a magnetoelectric material, wherein the magnetoelectric material has the following structure: N a Fe 3-a O b Wherein, N includes at least one of Co, Mn, Zn and Ni, a is a number from 0.25 to 1.5, and b is 4.

[0042] It is understood that the magnetoelectric nanoparticles described in this invention may or may not contain doping elements. When doping elements are present, the doping elements include, but are not limited to, at least one of carbon, nitrogen, phosphorus, sulfur, silicon, aluminum, iron, titanium, nickel, manganese, copper, silver, and zinc, thereby improving the piezoelectric properties and / or magnetoelectric response properties of the magnetoelectric nanoparticles.

[0043] In this invention, the average particle size of the magnetoelectric nanoparticles is generally 100-500nm, preferably 200-400nm, even more preferably 200-300nm, further preferably 220-260nm, and most preferably 220-240nm, for example 220, 222, 224, 226, 228, 230, 232, 234, 236, 238, 240nm.

[0044] In this invention, the preparation of the magnetoelectric nanoparticles is not particularly limited. Shell structures with piezoelectric properties and core structures with magnetoelectric response properties can be prepared using methods known in the art. It is understood that arbitrary doping elements or other layer structures may be contained between the shell structure and the core structure, in the outer layer of the shell structure and in the core structure to improve the piezoelectric properties and / or magnetoelectric response properties of the nanoparticles.

[0045] In this invention, "piezoelectric performance" refers to the ability of the shell structure of the nanoparticles in the magnetoelectric support coating to convert the mechanical energy from the core structure into electrical energy.

[0046] In this invention, "external field driving" refers to the generation of surface potential and minute displacement of magnetoelectric nanoparticles in the porous coating of the magnetic scaffold under the action of an external magnetic field, thereby applying magnetoelectric and mechanical stimulation to surrounding cells. Those skilled in the art will understand that the dynamic balance of bone tissue is regulated by many biological, chemical, and physical environmental factors; when bone tissue is damaged, its surrounding magnetoelectric microenvironment is disrupted. This invention utilizes the magnetoelectric microenvironment provided by the magnetoelectric scaffold to better meet the dynamic needs of angiogenesis-osteoogenesis coupling under pathological conditions, thereby promoting bone repair.

[0047] In a preferred embodiment, the "external field drive" includes treating the magnetoelectric support with a magnetic field strength of 0.01-300 mT and a frequency of 0.1-100 kHz. The magnetic field strength is also preferably 0.1-200 mT, more preferably 0.5-100 mT, more preferably 0.5-50 mT, and most preferably 0.5-10 mT, for example, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10 mT. The frequency is also preferably 0.5-50 kHz, more preferably 1-10 kHz, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 kHz.

[0048] In a second aspect, the present invention provides a method for preparing a magnetoelectric scaffold for bone repair under external field drive, including but not limited to the following steps: (1) providing a magnetoelectric nanoparticle mother liquor, which comprises a polymer obtained by acid monomer polymerization, magnetoelectric nanoparticles and a solvent; and (2) placing a scaffold body based on a triple-period minimal surface structure into the magnetoelectric nanoparticle mother liquor for treatment, and then removing and drying it.

[0049] In this invention, the "polymer obtained by acidic monomer polymerization" is selected from one or more of polyacrylic acid (PAA), polylactic acid (PLA), polylactic-co-glycolic acid (PLGA), polymethacrylic acid (PMAA), polyitacrylic acid (PIA), polystyrene sulfonic acid (PSS), polyAMPS (PAMPS), polyvinylphosphonic acid (PVPA), and polyMEP (PMEP). Preferably, one or more of polyacrylic acid (PAA), polylactic acid (PLA), polylactic-co-glycolic acid (PLGA), and polymethacrylic acid (PMAA) are selected.

[0050] In this invention, the "solvent" is selected from one or more of N,N-dimethylformamide, dichloromethane, dimethyl sulfoxide, dimethylamide, N-methylpyrrolidone, chloroform, formic acid, and acetic acid. Preferably, it is one or more of dichloromethane, dimethyl sulfoxide, dimethylamide, and chloroform. More preferably, it is dichloromethane.

[0051] In this invention, the weight percentage of the magnetoelectric nanoparticles to the mother liquor is generally 0.1%-5%, preferably 0.2%-3.5%, and more preferably 0.25%-3%. The concentration should not be too high or too low; too high a concentration will affect cell compatibility, while too low a concentration will affect the bone differentiation promotion effect. In a preferred embodiment of this invention, the weight percentage of the magnetoelectric nanoparticles to the mother liquor is 1%-2.5%. For example, the weight percentage of the magnetoelectric nanoparticles to the mother liquor is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, or 3.5%, etc. Preferably, the weight percentage of the magnetoelectric nanoparticles to the mother liquor is 2%.

[0052] In this invention, the weight percentage of the polymer obtained from the acidic monomer polymerization to the mother liquor is generally 2-10%, preferably 3-8%, and more preferably 4-6%. For example, the weight percentage of the polymer obtained from the acidic monomer polymerization to the mother liquor is 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, or 8%, etc. This weight percentage concentration should not be too high or too low; too high a concentration will clog the pores of the support, while too low a concentration will prevent uniform coverage on the support surface. In a preferred embodiment of this invention, the weight percentage of the polymer obtained from the acidic monomer polymerization to the mother liquor is 4-6%. Preferably, the weight percentage of the polymer obtained from the acidic monomer polymerization to the mother liquor is 5%.

[0053] In this invention, the scaffold body is preferably acid-etched before being immersed in the magnetoelectric nanoparticle mother liquor for treatment. This invention does not specifically limit the acid etching method; diluted hydrochloric acid, sulfuric acid, nitric acid, or phosphoric acid (one or more of these) can be used. In one specific embodiment of this invention, dilute hydrochloric acid is used for acid etching. In a preferred embodiment, 0.5M hydrochloric acid is used for acid etching.

[0054] In one specific embodiment of the present invention, the drying is vacuum drying.

[0055] In one specific embodiment of the present invention, the scaffold body is placed in the magnetoelectric nanoparticle mother liquor for treatment, which is ultrasonic treatment.

[0056] A third aspect of the present invention provides the use of a magnetoelectric scaffold for bone repair under external field drive. Preferably, the use is to promote osteogenic-angiogenic coupling. Preferably, the promotion of osteogenic coupling includes at least one of the following: (1) increased bone density; (2) promotion of new bone tissue formation; (3) promotion of expression of osteogenic-related genes. Preferably, the promotion of angiogenesis includes at least one of the following: (1) expression of angiogenic genes; (2) formation of vascular lumen structures.

[0057] A fourth aspect of the present invention provides a method for regulating in vitro cell phenotypes using an externally driven magnetic electric scaffold, wherein the cells include, for example, mesenchymal stem cells, macrophages, osteoblasts, osteoclasts, vascular endothelial cells, fibroblasts, myogenic cells, or immune cells. Preferably, the externally driven magnetic electric scaffold is used to regulate the osteogenic and angiogenic differentiation of mesenchymal stem cells.

[0058] Example I. Preparation of Exemplary Magnetoelectric Nanoparticles 1.1 Preparation of nuclear nanoparticles This embodiment uses the hydrothermal method as an example to illustrate the preparation of nuclear nanoparticles. Specifically, ethylene glycol, NaOH, FeCl3•6H2O, and CoCl3•6H2O are selected as raw materials. During the experiment, the content of the added mineralizing agent NaOH is adjusted to obtain ferromagnetic particle samples with stable morphology, particle size, and magnetic properties.

[0059] 1.2 Preparation of shell material nanoparticles BiFeO3 nanoparticles were synthesized from Bi(NO3)3•5H2O, Fe(NO3)3•9H2O, glacial acetic acid, and ethylene glycol via a sol-gel process.

[0060] 1.3 Preparation of core-shell nanostructured magnetoelectric composite materials The core-shell nanostructure consists of an inner core and an outer shell. The inner core is made of a ferromagnetic material, while the outer shell is made of a ferroelectric material, i.e., a BiFeO3 shell is coated onto the outer layer of CoFe2O4 nanoparticles. First, high-performance CoFe2O4 nanoparticles are prepared via a hydrothermal method. Then, a BiFeO3 precursor solution is prepared separately. The CoFe2O4 nanoparticles are then placed in the BiFeO3 precursor solution, and ultrasonic vibration is used to reduce powder agglomeration, ensuring uniform dispersion in the solution. After drying to form a gel, heat treatment is performed to obtain a well-crystallized BiFeO3 shell on the outer layer of the CoFe2O4 nanoparticles. In other words, a BiFeO3 shell is coated onto the surface of the prepared CoFe2O4 nanoparticles using the sol-gel method, resulting in a core-shell nanostructured magnetoelectric composite material, thus completing the sample preparation.

[0061] 1.4 Characterization of core-shell nanostructured magnetoelectric composite materials ( Figure 1 ).

[0062] Figure 1 The SEM and EDS results in a and b clearly show the core-shell structure of the nanoparticles. Figure 1 XRD results in c show that the sample is composed of CoFe2O4 and BiFeO3. Figure 1 The VSM and PFM tests of d and 1e verified the strong magnetism of the core and the piezoelectricity of the shell, and the rhodamine decomposition experiment was used to verify the core's strong magnetism and shell's piezoelectricity. Figure 1 f) The magnetoelectric coupling effect of the particles was verified.

[0063] II. Exemplary Method for Preparing a Magnetoelectric Support Preparation process as follows Figure 5 As shown in a, specifically: 1. Using β-TCP as the slurry, G-TPMS scaffolds were prepared using digital processing (DLP) photopolymerization 3D printing technology; then, the G-TPMS scaffolds were etched with 0.5M hydrochloric acid for 30 minutes, rinsed with running water for 5 minutes to remove residual hydrochloric acid, and dried in an oven at 37℃ to obtain the etched G-TPMS scaffolds for later use. 2. Add magnetoelectric nanoparticles to dichloromethane and ultrasonically disperse for 10 min to obtain a particulate dichloromethane suspension; after drying and pretreating PLA (180,000-250,000 MW), add it to the particulate dichloromethane suspension, shake on a horizontal shaker for 10 min, and then ultrasonically disperse for 10 min. Repeat the shaking and ultrasonication at least 3 times to obtain a stable coating sol. 3. Suspend the acid-etched G-TPMS scaffold in the coating sol and sonicate for 10 minutes; 4. The scaffold was suspended in a sealed beaker with a thin filament and allowed to settle naturally for 2 hours. Then, the sample was suspended in a centrifuge tube and centrifuged. After that, the scaffold aperture was opened with slight air pressure and dried in an oven at 37°C to obtain the TP@CB scaffold.

[0064] III. Screening of PLA Concentration in Scaffold Coating 3.1 Preparation of scaffolds with different PLA concentration coatings 1) After drying and pretreating PLA (180,000-250,000 MW), dissolve it in dichloromethane to prepare PLA sols with mass fractions of 1%, 2%, 5%, and 10%, respectively. 2) The acid-etched G-TPMS scaffolds prepared in step 1 of Part 2 were suspended in PLA sols of different concentrations and subjected to ultrasonic treatment. 3) Following the steps of sedimentation, centrifugation, and opening the scaffold aperture in step 4 of Part 2, TPMS scaffolds coated with PLA coatings of different concentrations are obtained.

[0065] 3.2 Testing of TPMS scaffolds with different concentrations of PLA coating As shown in the SEM image ( Figure 2 As shown in the figure, when the PLA content is too low, i.e., the 1% and 2% concentration groups of the magnetoelectric scaffold coating have a large number of honeycomb-like pores that cannot be uniformly covered on the scaffold surface; while when the PLA concentration is too high, for example, 10% concentration PLA has poor fluidity, and a large number of scaffold pore structures are blocked; in contrast, 5% concentration PLA forms a uniform coating on the scaffold surface and does not block the scaffold pores, so the 5% concentration PLA coating is better.

[0066] The magnetoelectric support of this invention is manufactured by 3D printing using β-TCP as the paste. (See EDS elemental analysis diagram). Figure 3 As shown, the C element content of the uncoated TPMS scaffold was 4.65% (wt%), while the C element content of the 5% PLA-coated magnetoelectric scaffold increased to 55.12% (wt%), confirming that 5% PLA (main component C) formed a uniform coating on the surface of the β-TCP scaffold (main components P, Ca, O).

[0067] IV. Screening of Magnetoelectric Particle Concentration for Magnetoelectric Support Load 4.1 Fabrication of scaffolds loaded with magnetoelectric particles of different concentrations 1) Magnetoelectric nanoparticles were added to dichloromethane to prepare dichloromethane solutions with mass fraction concentrations of 0.25%, 0.5%, 1%, 2%, 4%, and 8%, respectively. The solutions were ultrasonically dispersed for 10 min to obtain dichloromethane suspensions of different concentrations. PLA (180,000-250,000 MW) was dried and pretreated, then added to the dichloromethane suspension (PLA concentration of 5%). The mixture was shaken on a horizontal shaker and then ultrasonically dispersed. The shaking and ultrasonic treatments were repeated at least 3 times to obtain stable coating sols with different concentrations of magnetoelectric nanoparticles. 2) The acid-etched G-TPMS scaffolds prepared using the method in step 1 of Part 2 were suspended in coating sols with different concentrations of the above-mentioned magnetoelectric nanoparticles and then ultrasonically treated. 3) Following the steps of sedimentation, centrifugation, and opening the scaffold aperture in step 4 of Part 2, TPMS scaffolds with different concentrations of magnetoelectric nanoparticles were obtained.

[0068] 4.2 Cytotoxicity experiments of scaffolds loaded with different concentrations of magnetoelectric particles Rat bone marrow mesenchymal stem cells (rBMSCs) were cultured on a scaffold, and cell viability on the scaffold was assessed. Figure 4 The results showed that on day 7 of culture, the cell viability on scaffolds loaded with 4% and 8% magnetoelectric particles decreased to less than 90% of that in the control group. Therefore, the optimal concentration of magnetoelectric nanoparticles loaded on the scaffold was determined to be 2%.

[0069] V. Preferred Preparation Method of Magnetoelectric Support 5.1 Preparation method Magnetoelectric nanoparticles were added to dichloromethane to prepare a 2% dichloromethane solution, which was then ultrasonically dispersed for 10 min to obtain a magnetoelectric dichloromethane suspension. PLA (180,000-250,000 Mw) was pre-treated by drying and then added to the magnetoelectric dichloromethane suspension to prepare a 5% PLA coating solution. The remaining operations were the same as in Part II, resulting in the preparation of the TP@CB scaffold.

[0070] 5.2 Characterization of the stent For detailed characterization results, see [link to specific characterization results]. Figure 5 . Figure 5 bd proved that the PLA coating successfully loaded magnetoelectric particles onto the surface of the TPMS scaffold; Figure 5 e proves that the stent is magnetic. Figure 5 As can be seen from f, the output voltage of the bracket under the influence of the magnetic field is approximately 0.15V. Figure 5 gh proves that the scaffold generates surface charge and voids under the action of a magnetic field, which then react with surrounding water and oxygen to generate hydroxyl radicals and superoxide radicals, ultimately decomposing the organic dye Rhodamine B. Figure 5 The results show that compared with the simple TPMS scaffold, the compressive strength of the magnetoelectric scaffold TP@CB is significantly improved, while the hydrophilicity and porosity of the scaffold are not significantly changed. Figure 5 k indicates that Co, Fe, and Ca ions in the magnetoelectric scaffold TP@CB are released slowly and uniformly throughout the 0-28 day period.

[0071] Test case I. Cell proliferation and adhesion experiments This experiment demonstrates the effects of magnetoelectric stimulation mediated by the exemplary magnetoelectric scaffold of this invention on cell compatibility, cell proliferation, and adhesion. Experimental diagrams and results are shown below. Figure 6 Specifically: To determine the cell compatibility of the scaffolds, BMSCs were cultured for 48 h on TPMS scaffolds and the magnetoelectric scaffold TP@CB prepared in Part 5, respectively, followed by SEM and live / dead cell staining. Figure 6 b) and staining of live and dead cells ( Figure 6 c). The results showed that the cells were morphologically intact and spread well on TPMS and TP@CB, indicating that both TPMS and TP@CB had good cell compatibility.

[0072] Next, the effect of TP@CB-mediated magnetoelectric stimulation (1.5 mT) on cell proliferation under magnetic field was analyzed. Four experimental groups were set up: TPMS, TP-M (TPMS with external magnetic field applied), TP@CB, and TP@CB-M (TP@CB with external magnetic field applied). BMSCs were seeded on TPMS and TP@CB (the scaffold was placed at the bottom of the culture plate), and after 12 h of culture, a magnetic field was directly applied to the culture plate (30 min / day). CCK8 assays were performed at days 1, 3, and 7. Results ( Figure 6 d) showed that the cell proliferation capacity of the TP@CB-M group was significantly improved, meaning that under the action of an external magnetic field, TP@CB-mediated magnetoelectric stimulation could promote cell proliferation on the scaffold; then, TPMS and TP@CB scaffolds were immersed in BSA solution, thoroughly mixed, and then adsorbed by applying a magnetic field. The absorbance of the supernatant was measured using a UV-Vis spectrophotometer. The results ( Figure 6 e) The magnetic field significantly improved the adsorption performance of TP@CB.

[0073] Finally, the effect of TP@CB on cell adhesion under magnetic field irradiation was investigated using Vinculin staining. BMSCs were seeded on TPMS and TP@CB, cultured for 12 h, and then a magnetic field was applied (30 min / day). Staining was performed at 24 h. The results were... Figure 6 f) shows that TP@CB-mediated magnetoelectric stimulation significantly improved cell adhesion.

[0074] II. In vitro osteogenic differentiation experiment This experiment demonstrates the regulatory effect of TP@CB-mediated magnetoelectric stimulation on osteogenic differentiation in vitro. Experimental diagrams and results are shown below. Figure 7 Specifically: This experiment used the same grouping and magnetic field application method as in Experiment 1. BMSCs were seeded onto the TPMS scaffold and the magnetoelectric scaffold TP@CB prepared in Part 5, and then a magnetic field was applied. Osteogenesis-related gene PCR detection was performed at days 3 and 7. Results ( Figure 7 (b) TP@CB-mediated magnetoelectric stimulation showed that it increased the expression of Runx-2 (day 3), BMP-2 (day 3), OPN (day 7), and OCN (day 7). ALP staining and Alizarin Red staining were performed at 14 and 28 days of culture, respectively, and the results ( Figure 7 (c-7d) showed that TP@CB-mediated magnetoelectric stimulation enhanced ALP activity and osteogenic mineralization capacity of BMSCs. BMP-2 immunofluorescence staining was performed on day 3 of culture, and OPN immunofluorescence staining was performed on day 7. Results ( Figure 7(e-7f) showed that TP@CB-mediated magnetoelectric stimulation increased the expression levels of BMP-2 and OPN osteogenic-related proteins in BMSCs. In summary, TP@CB-mediated magnetoelectric stimulation has a better positive regulatory effect on osteogenic differentiation.

[0075] III. In vitro angiogenesis experiment This experiment demonstrates the regulatory effect of TP@CB-mediated magnetoelectric stimulation on angiogenesis differentiation. Experimental diagrams and results are shown below. Figure 8 Specifically: The experimental grouping and magnetic field application method were the same as in Part 1 of the test cases. HUVECs were seeded on a scaffold, and after applying the magnetic field, the cells were digested, resuspended, and seeded in Transwell chambers. After 12 hours, photographs were taken to investigate the effect of TP@CB on the migration ability of HUVECs. Results (…) Figure 8 b) showed that TP@CB-mediated magnetoelectric stimulation significantly improved cell migration ability; HUVECs were seeded on a scaffold, and PCR detection of angiogenesis-related genes was performed at 48 h, with results ( Figure 8 c) This showed that TP@CB-mediated magnetoelectric stimulation increased the expression of angiogenic genes; HUVECs were seeded on a scaffold, and after applying a magnetic field, the cells were digested, resuspended, and then subjected to angiogenesis experiments. The results ( Figure 8 d) The TP@CB-M group showed the most luminal structures, indicating that TP@CB-mediated magnetoelectric stimulation can enhance the angiogenic capacity of HUVECs; finally, HUVECs were seeded onto a scaffold, and immunofluorescence staining for the endothelial cell marker CD31 was performed at 48 h. The results ( Figure 8 e) This demonstrates that TP@CB-mediated magnetoelectric stimulation enhances CD31 expression. In summary, TP@CB-mediated magnetoelectric stimulation better promotes HUVEC migration and angiogenesis differentiation.

[0076] IV. Osteogenesis Experiment in Rats This experiment demonstrates the regulatory effect of TP@CB-mediated magnetoelectric stimulation on osteogenic differentiation of the rat skull under normal and inflammatory conditions. Experimental diagrams and results are shown below. Figure 9 and Figure 10 Specifically: First, a critical bone defect model of normal rat skull was established. After the scaffold was implanted into the rat skull defect, an external magnetic field (1.5 mT) was continuously applied to the rats for 2 weeks, and tissue samples were taken for CT scans at 4, 8, and 12 weeks. The results were as follows: Figure 9 bc) showed that the TP@CB-M group had the largest volume of newly formed bone within the defect; after the CT scan, the skull samples were decalcified, sectioned, stained, and subjected to CD31 / OPN double staining immunofluorescence ( Figure 9d) showed that the expression levels of endothelial cell markers CD31 and osteogenic-associated protein OPN were significantly increased in the TP@CB-M group; HE and Masson staining results ( Figure 9 e) The TP@CB-M group showed the highest number and most mature new bone formation within the scaffold. In summary, TP@CB-M significantly promoted the repair of bone defects. Specifically, after TP@CB is implanted into the defect, the scaffold-mediated magnetoelectric stimulation under the influence of an external magnetic field can create a magnetoelectric microenvironment conducive to bone repair, and can better positively regulate angiogenesis-osteogenic coupling.

[0077] Next, a critical bone defect model of the rat skull under inflammatory conditions was established. For example... Figure 10 As shown in figure a, after a rat inflammation model was induced by intraperitoneal injection of LPS for one week, a scaffold was implanted into the skull defect, and an external magnetic field (1.5 mT) was continuously applied to the rats for two weeks. Immunofluorescence ( Figure 10 d) Results showed that the expression levels of CD31 and OPN were significantly increased in the TP@CB-M group, and CT ( Figure 10 bc) and tissue staining ( Figure 10 e) The results showed that the TP@CB-M group had the highest number and most mature new bone formation within the scaffold. In conclusion, after TP@CB is implanted into the defect, under the influence of an external magnetic field, it can positively regulate vascular-osteogenic coupling under inflammatory pathological conditions.

[0078] V. Osteogenesis Experiment in Beagle Dogs This experiment demonstrates the regulatory role of TP@CB-mediated magnetoelectric stimulation in osteogenic differentiation of the alveolar bone in canines. Experimental diagrams and results are shown below. Figure 11 Specifically: After confirming that TP@CB-mediated magnetoelectric stimulation can positively modulate angiogenesis-osteogenic coupling, a vertical bone defect model of the alveolar bone in beagle dogs was established. Based on previous in vitro and in vivo experimental results, a TPMS-only group and a TP@CB-M group were set up to demonstrate the effect of TP@CB-mediated magnetoelectric stimulation on vertical bone augmentation. An additional clinical method for vertical bone augmentation (bone powder + barrier membrane) was added as a control group (Ctrl).

[0079] like Figure 11 As shown in b, the bilateral mandibular premolars of the beagle were first extracted (①, ②). After 3 months of alveolar socket healing, vertical bone defects were prepared (③, ④). In the control group, bone powder was filled, covered with a barrier membrane, and fixed with membrane staples (⑤, ⑥). In the TPMS and TP@CB-M groups, the framework was implanted and fixed with titanium staples (⑦, ⑧). A magnetic field (1.5 mT) was applied for 1 month postoperatively, and CBCT scans were taken at 1.5 and 3 months. The results were as follows ( Figure 11 c) shows that the TP@CB-M group framework exhibits excellent osseointegration and osseointegration with the surrounding alveolar bone; similarly, the Micro-CT results 3 months postoperatively ( Figure 11 The results showed that the TP@CB-M group had the best new bone height, volume, and bone mineral density.

[0080] In summary, the TP@CB scaffold, under the influence of an external magnetic field, can not only accelerate bone regeneration but also promote the restoration of the vertical bone height of the alveolar bone.

[0081] VI. In vivo safety experiments This experiment verified the in vivo safety of TP@CB; the experimental results are shown below. Figure 12 Specifically: First, a hemolysis experiment was performed on the scaffold. The scaffold was immersed in a suspension of red blood cells and incubated at 37°C for 1 hour. After centrifugation, the supernatant was collected for absorbance analysis. The results were as follows: Figure 12 a) The hemolysis rate in the TP@CB group was less than 5%, indicating that the scaffold would not cause hemolysis of erythrocytes. Furthermore, 12 weeks after TP@CB implantation in rats, visceral tissue samples were collected for HE staining, and the results showed ( Figure 12 b) The stent did not show significant visceral toxicity, indicating that it has good biocompatibility after implantation.

[0082] Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. Various adjustments or changes may be made to the exemplary embodiments described in this specification without departing from the scope or spirit of the invention. The scope of the claims should be interpreted in the broadest possible sense to cover all modifications and equivalent structures and functions.

Claims

1. A magneto-electric scaffold for bone repair under an external field, characterized in that, The scaffold body comprises a convoluted and / or through-hole structure, and the magnetoelectric nanoparticle coating is loaded on the inner surface of at least part of the hole structure, wherein the magnetoelectric nanoparticle comprises a shell structure with piezoelectric properties and a core structure with magnetoelectric response properties.

2. The magnetoelectric scaffold for bone repair under an external field driving according to claim 1, wherein, The pore diameter of the hole structure is 100-500 μm, and the particle size of the magnetoelectric nanoparticle is 100-500 nm.

3. The magnetoelectric scaffold for bone repair under an external field driving according to claim 1, wherein, The scaffold body material comprises one or more of chitosan, gelatin, collagen, fibrin, elastin, alginate, polycaprolactone, polylactic acid, poly-lactic-glycolic acid, polyether ether ketone, hydroxyapatite, tricalcium phosphate, calcium silicate and bone cement.

4. The magnetoelectric scaffold for bone repair under an external field driving according to claim 1, wherein, The magnetoelectric nanoparticle coating comprises a polymer obtained by polymerization of an acidic monomer.

5. The magnetoelectric scaffold for bone repair under an external field driving according to claim 1, wherein, The shell structure of the magnetoelectric nanoparticle is prepared from an inorganic piezoelectric material and / or an organic piezoelectric material, and the core structure of the magnetoelectric nanoparticle is prepared from a magnetoelectric material.

6. The magnetoelectric scaffold for bone repair under an external field driving according to claim 5, wherein, The inorganic piezoelectric material is selected from at least one of ferrite, niobate, titanate, silicate and aluminate materials; wherein the ferrite material has the following structure: M x Fe 2-x O y wherein M comprises at least one of Bi, Ca, Mg and Ba, x is a number from 0.25 to 1.5, and y is 3. The organic piezoelectric material is selected from at least one of polyvinylidene fluoride, polyester, polymethyl methacrylate, nylon, polyvinyl chloride, poly-L-lactide, poly(3-hydroxybutyrate-CO-3-hydroxyvalerate), vinylidene fluoride / trifluoroethylene copolymer, vinylidene fluoride / tetrafluoroethylene copolymer, polyvinylidene fluoride-hexafluoropropylene and polydimethylsiloxane material; The chemical formula of the magnetoelectric material is: N a Fe 3-a O b wherein N represents at least one of Co, Mn, Zn and Ni, a is a number of 0.25 to 1.5, and b is 4.

7. A method for preparing a magneto-electric scaffold for bone repair under an external field, characterized in that, The method comprises the following steps: (1) providing a magnetoelectric nanoparticle mother liquor comprising a polymer obtained by polymerization of an acidic monomer, magnetoelectric nanoparticles and a solvent; and (2) placing a scaffold body based on a triply periodic minimal surface structure into the magnetoelectric nanoparticle mother liquor for treatment, then taking out and drying.

8. The method of claim 7, wherein the method further comprises the step of: The weight percentage of the magnetoelectric nanoparticles in the mother liquor is 0.2%-3.5%.

9. Use of the magnetoelectric scaffold for bone repair under external field driving according to any one of claims 1-6.

10. Use according to claim 9, characterized in that, The use is oral clinical alveolar bone vertical bone augmentation and bone defect repair in systemic diseases. The use is oral clinical alveolar bone vertical bone augmentation and bone defect repair in systemic diseases.

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