Bone repair porous tissue engineering scaffold with electromagnetic response as well as preparation method and application thereof

Abstract

The invention discloses a bone repair porous tissue engineering scaffold with electromagnetic response as well as a preparation method and application thereof, and belongs to the field of medical materials. According to the invention, superparamagnetic nanoparticles are uniformly embedded into a high-molecular bionic porous scaffold, and a 3D printing technology is combined, so that the hierarchical porous scaffold with both macroscopic mechanical strength and microscopic biological activity is constructed. A porous structure is used for simulating an extracellular matrix of a bone, and the osseointegration efficiency is optimized. Meanwhile, in combination with the electromagnetic response characteristic of the stent, osteogenic differentiation of mesenchymal stem cells is dynamically regulated and induced and angiogenesis is accelerated through an external electromagnetic field, and a new-generation repair stent with mechanical adaptability, biological activity and intelligent responsiveness is provided for clinical refractory bone defects through interdisciplinary technology fusion; therefore, a'material-cell-microenvironment 'triple synergistic repair mechanism is realized.

Description

Technical Field

[0001] The present invention relates to the field of biomedical materials and preparation methods thereof, and in particular to a porous tissue engineering scaffold with electromagnetic response for bone repair, and a preparation method and application thereof. Background Art

[0002] Bone defect repair is a major challenge in orthopedic clinical practice, especially for large load-bearing bone defects or complex morphological defects. Existing materials still have significant limitations in mechanical properties, bioactivity and functional regulation. Traditional bone repair materials such as bioinert metals (titanium alloys, stainless steel) have elastic modulus mismatch, which can easily lead to problems such as stress shielding effect. Bioceramics (hydroxyapatite, tricalcium phosphate) are highly brittle, and the degradation rate is difficult to meet the physiological needs of bone regeneration. Degradable polymers (polylactic acid, chitosan) have problems such as insufficient mechanical strength. In addition, current orthopedic implant materials are difficult to respond to external stimuli (such as electric fields or magnetic fields) after implantation in the body, and their bioactive functions are often insufficient, which to a certain extent limits their application in clinical scenarios.

[0003] Currently, magnetic nanoparticles, such as Fe3O4 and γ-Fe2O3, have become a research hotspot in bone tissue engineering due to their superparamagnetic, electromagnetically responsive, and biocompatible properties. Studies have shown that magnetic nanoparticles can induce changes in intracellular signaling by generating mechanical stimulation. Furthermore, magnetic nanoparticles can bind to proteins associated with cell surfaces, thereby controlling and regulating cellular function. Nanoparticles such as Fe3O4 and γ-Fe2O3 exhibit superparamagnetism below a critical size. Nanoparticles with superparamagnetic response exhibit a strong magnetic effect only in the presence of an applied magnetic field, but not in the absence of an applied magnetic field. However, in practical applications, it has been found that pure nanoparticles may have limited magnetic field strength, resulting in weak magnetic response, which may not meet the requirements for clinical efficacy. This suggests that the biological function of nanoparticles may be enhanced through external electromagnetic field stimulation. Studies have shown that magnetic nanoparticles can induce localized micro-electromagnetic fields through applied electric or magnetic fields, promoting osteoblast differentiation and accelerating mineral deposition, effectively promoting the in vivo bone formation of implants. Furthermore, during the degradation process, magnetic nanoparticles produce Fe 3+ , Fe 3+ It can promote the expression of angiogenic factors in human umbilical vein endothelial cells (HUVEC) and promote the formation of blood vessels. The growth of new blood vessels can not only strengthen the blood supply to the affected area and provide sufficient nutrients to the affected tissue, but also accelerate the recruitment of osteoblast-related cells and promote the regeneration of new bone.2+ 、Fe 3+ However, if high concentrations of nanoparticles are released into the tissue, they may cause certain cytotoxic effects. At the same time, nanoparticles may also cause immune reactions at the implant site, leading to adverse consequences such as sterility verification reactions and tissue damage, which is not conducive to the regeneration of the affected tissue. Summary of the Invention

[0004] The purpose of the present invention is to provide a porous tissue engineering scaffold with electromagnetic response for bone repair, as well as its preparation method and application. The tissue engineering scaffold of the present invention has good biocompatibility and bioactivity, can meet the requirements of mechanical properties, has the function of promoting new blood vessels and new bone formation, and can also be used as a medical implant material.

[0005] The present invention provides an orthopedic implant material with integrated electromagnetic responsiveness and a multi-level porous structure. By uniformly embedding superparamagnetic nanoparticles into a polymer biomimetic porous scaffold and combining it with 3D printing technology, a hierarchical porous scaffold with both macroscopic mechanical strength and microscopic bioactivity is constructed. The porous structure is used to simulate the extracellular matrix of bone cells and optimize bone integration efficiency. At the same time, combined with the electromagnetic response characteristics of the scaffold, the osteogenic differentiation of mesenchymal stem cells is induced and angiogenesis is accelerated through dynamic regulation of an external electromagnetic field. Through interdisciplinary technology integration, a new generation of repair scaffold with mechanical adaptability, bioactivity and intelligent responsiveness is provided for clinically refractory bone defects, thereby realizing the triple synergistic repair mechanism of "material-cell-microenvironment".

[0006] First, the present invention provides an application of an electromagnetically responsive porous tissue engineering scaffold for bone repair and an electric field emission source and / or a magnetic field emission source in the preparation of a product for treating bone defects or bone necrosis.

[0007] In the above application, the raw materials for preparing the electromagnetic responsive porous tissue engineering scaffold for bone repair include the following components in percentage by weight: 80%-95% of polylactic acid-glycolic acid copolymer and 5%-20% of γ-Fe2O3 nanoparticles or Fe3O4 nanoparticles.

[0008] In the above application, the particle size of the γ-Fe2O3 nanoparticles or Fe3O4 nanoparticles is 10-20 nm.

[0009] In the above application, the method for preparing the porous tissue engineering scaffold with electromagnetic response for bone repair comprises the following steps:

[0010] (1) mixing the polylactic acid-co-glycolic acid copolymer, γ-Fe2O3 nanoparticles or Fe3O4 nanoparticles and an organic solvent to form a homogeneous solution;

[0011] (2) Using solid model design software to create a model, and exporting the data containing the model, and then using layering software to layer the data of the model to obtain layered data, and generate a corresponding format file;

[0012] (3) adding the homogeneous solution of step (1) to a low-temperature rapid prototyping device, setting printing parameters according to the format file of the structure designed in step (2), and then performing printing and shaping at -40°C to -20°C to obtain a formed porous scaffold;

[0013] (4) freeze-drying the formed porous scaffold to obtain the electromagnetically responsive porous tissue engineering scaffold for bone repair.

[0014] In the above application, the organic solvent is 1,4-dioxane and / or chloroform;

[0015] The concentration of the poly(lactic acid-co-glycolic acid) in 1,4-dioxane is 0.05-0.5 g / mL.

[0016] In the above application, the electric field emission source generates an alternating electric field or an electrostatic field;

[0017] The magnetic field emission source generates an alternating magnetic field or a static magnetic field.

[0018] In the above application, the electric field strength of the alternating electric field is 0.01-10 v / cm and the frequency is 1-20 Hz;

[0019] The intensity of the electrostatic field is 0.01-10v / cm;

[0020] The alternating magnetic field has a magnetic field strength of 0.01-10 mT and a frequency of 1-100 Hz;

[0021] The intensity of the static magnetic field is 10-200 mT.

[0022] Furthermore, the present invention provides a product for treating bone defects or bone necrosis, comprising a porous tissue engineering scaffold for bone repair having an electromagnetic response and an electric field emission source and / or a magnetic field emission source.

[0023] In the above product, the raw materials for preparing the electromagnetic responsive porous tissue engineering scaffold for bone repair include the following components in percentage by weight: 80%-95% of polylactic acid-glycolic acid copolymer and 5%-20% of γ-Fe2O3 nanoparticles or Fe3O4 nanoparticles.

[0024] In the above-mentioned product, the electric field emission source generates an alternating electric field or an electrostatic field;

[0025] The magnetic field emission source generates an alternating magnetic field or a static magnetic field.

[0026] In the above-mentioned product, the electric field strength of the alternating electric field is 0.01-10 v / cm, and the frequency is 1-20 Hz;

[0027] The intensity of the electrostatic field is 0.01-10v / cm;

[0028] The alternating magnetic field has a magnetic field strength of 0.01-10 mT and a frequency of 1-100 Hz;

[0029] The intensity of the static magnetic field is 10-200 mT.

[0030] The present invention has the following beneficial effects:

[0031] The electromagnetically responsive porous tissue engineering scaffold for bone repair of the present invention has good biocompatibility and bioactivity. It can not only promote the generation of new blood vessels, but also promote the regeneration of new bone at the implantation site, thereby accelerating the healing of bone tissue in the affected area. At the same time, its application potential can be enhanced by using appropriate electromagnetic stimulation. It is a relatively promising orthopedic tissue engineering scaffold suitable for the field of orthopedic implant devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The macromorphology of pure PLGA, 10%γ-Fe2O3 and 20%γ-Fe2O3 scaffolds;

[0033] Figure 2 The scanning electron micrographs of pure PLGA, 10% γ-Fe2O3, and 20% γ-Fe2O3 scaffolds;

[0034] Figure 3 Magnetic hysteresis regression lines of 10%γ-Fe2O3 and 20%γ-Fe2O3 scaffolds at 310K;

[0035] Figure 4 The cytotoxicity of pure PLGA, 10%γ-Fe2O3 and 20%γ-Fe2O3 scaffolds to BMSC and HUVEC cells with and without static magnetic field stimulation;

[0036] Figure 5 The ALP activity of pure PLGA, 10%γ-Fe2O3 and 20%γ-Fe2O3 scaffolds on BMSCs under the conditions of static magnetic field stimulation and without static magnetic field stimulation;

[0037] Figure 6 The ability of pure PLGA, 10%γ-Fe2O3 and 20%γ-Fe2O3 scaffolds to stimulate BMSCs to form osteoblasts in vitro under static magnetic field stimulation.

[0038] Figure 7The results of cell scratch experiments on pure PLGA, 10%γ-Fe2O3 and 20%γ-Fe2O3 scaffolds under static magnetic field stimulation are shown;

[0039] Figure 8 The tube-forming ability of HUVEC in pure PLGA, 10%γ-Fe2O3 and 20%γ-Fe2O3 scaffolds under the condition of static magnetic field stimulation;

[0040] Figure 9 Pure PLGA and 20%γ-Fe2O3 scaffolds promote new bone and angiogenesis in vivo under static magnetic field stimulation. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below in conjunction with specific embodiments. The examples given are only for illustrating the present invention, not for limiting the scope of the present invention.

[0042] The experimental methods in the following examples are conventional methods unless otherwise specified.

[0043] The quantitative tests in the following examples were performed in triplicate unless otherwise specified, and the results were averaged.

[0044] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0045] Example 1: Preparation of Electromagnetic Responsive Porous Tissue Engineering Scaffold for Bone Repair

[0046] The specific preparation method is as follows:

[0047] (1) According to the mass percentage, X% of PLGA (poly(lactic-co-glycolic acid)) and Y% of γ-Fe2O3 with a particle size of 10 nm were weighed and placed in a flask to make a total weight of 10 g. 100 mL of 1,4-dioxane solvent was then added and stirred overnight at room temperature to form a homogeneous solution. Where X = 80, 90, 95, 100, and Y = 20, 10, 5, 0;

[0048] (2) Use SolidWorks software to design and create a model, such as 1.4×1.4×1.4cm 3 A cube structure model is obtained, and data containing a SolidWorks model is exported, and the data containing the SolidWorks model is layered using layering software to obtain layered data, and a CLI file is generated;

[0049] (3) The homogeneous solution obtained in step (1) was added to the material tank of the low-temperature rapid prototyping machine and assembled; the printing parameters were set according to the CLI format file of the structure designed in step (2), wherein the spinneret spacing was 0.8 mm, the layer height was 0.14 mm, the nozzle speed was 11 mm / s, and the nozzle discharge speed was 1.2 mL / min. The printing was performed at -30°C to obtain a 1.4×1.4×1.4 cm 3 Cube block bracket;

[0050] (4) The block scaffold obtained above was freeze-dried in a freeze dryer for 72 hours to obtain a porous tissue engineering scaffold with electromagnetic response for bone repair.

[0051] The electromagnetic responsive porous tissue engineering scaffolds for bone repair prepared in Example 1 were photographed. The macroscopic morphologies of the prepared pure PLGA, 10% γ-Fe2O3 and 20% γ-Fe2O3 scaffolds are shown in Figure 1. Figure 1 As shown. Among them, Figure 1 The left picture is pure PLGA, the middle picture is a scaffold containing 10% γ-Fe2O3, and the right picture is a scaffold containing 20% γ-Fe2O3. Figure 1 It can be seen that the color of the electromagnetic responsive porous tissue engineering scaffold for bone repair prepared by the method of the present invention deepens as the number of nanoparticles increases, and the pore structures of different scaffolds are evenly arranged.

[0052] The stent prepared in Example 1 was cut into 2mm thick block samples. After spraying gold on the surface of the stent slices for 30 seconds using a vacuum coating machine, the stent micromorphology was observed using a scanning electron microscope at different magnifications. The micromorphology of the pure PLGA, 10% γ-Fe2O3 and 20% γ-Fe2O3 stents under the electron microscope is as follows: Figure 2 As shown. Figure 2 It can be seen that in addition to the uniformly sized holes inside the bracket, the bracket arm also presents a loose porous structure.

[0053] Example 2: Mechanical Properties Test of Electromagnetic Responsive Porous Tissue Engineering Scaffold for Bone Repair

[0054] According to the method in Example 1, a porous tissue engineering scaffold with electromagnetic response bone repair was prepared into a 10×10×10 mm 3 The compression test was carried out at room temperature using a universal mechanical testing machine at a compression rate of 1 mm / min. Six samples were selected from each group and their average value was measured.

[0055] The compressive strength and compression modulus of the pure PLGA, 10% γ-Fe2O3 and 20% γ-Fe2O3 scaffolds prepared in this example at room temperature are shown in Table 1.

[0056] Table 1 Mechanical strength of porous tissue engineering scaffolds with electromagnetic response for bone repair

[0057] (PLGA) <![CDATA[(PLGA / 10%γ-Fe2O3)]]> <![CDATA[(PLGA / 20%γ-Fe2O3)]]> Compression strength (MPa) 0.57±0.13 0.88±0.19 0.93±0.01 Compression modulus (MPa) 11.57±0.54 16.64±1.50 21.37±2.00

[0058] As shown in Table 1, after adding γ-Fe2O3, the compressive strength and compression modulus of the porous tissue engineering scaffold with electromagnetic response bone repair are greatly improved. The more γ-Fe2O3 is added, the greater the compressive strength and compression modulus are.

[0059] Example 3: Superparamagnetic testing of porous tissue engineering scaffolds with electromagnetic response for bone repair

[0060] The stent prepared in Example 1 was cut into 3×3×1 mm 3 After the bulk sample was prepared, the MH curve of the scaffold was measured at a temperature of 310K using a vibrating sample magnetometer in a magnetic field strength range of -7000 to 7000 Oe.

[0061] The hysteresis regression lines of the 10%γ-Fe2O3 and 20%γ-Fe2O3 scaffolds prepared by the present invention at 310K are as follows: Figure 3 As shown. Figure 3 It can be seen that the addition of magnetic nanoparticles makes the PLGA composite scaffold superparamagnetic, and as the content of nanoparticles increases, the superparamagnetism of the composite scaffold is enhanced.

[0062] Example 4: In vitro biocompatibility evaluation of a porous tissue engineering scaffold with electromagnetic response for bone repair

[0063] The scaffold prepared in Example 1 was cut into 2 mm thick block samples, and each side was sterilized by ultraviolet irradiation for 2 hours. The blocks were then placed in a 12-well plate and placed in an environment with a 100 mT static magnetic field and an environment without a static magnetic field. Cells were added to each well at a concentration of 1×10 4 Cell suspensions of human bone marrow mesenchymal stem cells (BMSCs, purchased from the National Biomedical Cell Resource Bank (BMCR) under the number 3101HUMSCSP405) and human umbilical vein endothelial cells (HUVECs, purchased from the National Biomedical Cell Resource Bank (BMCR) under the number 4201HUM-CCTCC00635) were cultured at 37°C in 5% CO2 for 1, 3, 5, and 7 days, respectively. At the designated time points, the cell viability of BMSCs and HUVECs was assessed using a CCK-8 cell viability assay kit with and without static magnetic field stimulation.

[0064] The cytotoxicity of pure PLGA, 10% γ-Fe2O3 and 20% γ-Fe2O3 scaffolds prepared by the present invention to BMSC and HUVEC cells under the conditions of static magnetic field stimulation and without static magnetic field stimulation is as follows: Figure 4 As shown. Figure 4 It can be seen that the addition of static magnetic field stimulation can increase the proliferation rate of BMSC and HUVEC cells in the scaffold.

[0065] Example 5: In vitro ALP activity evaluation of electromagnetically responsive porous tissue engineering scaffolds for bone repair

[0066] The scaffold prepared in Example 1 was cut into 2 mm thick block samples, and each side was sterilized by ultraviolet irradiation for 2 h. The blocks were then placed in 12-well plates and placed in a 100 mT static magnetic field. Cells were added to each well at a concentration of 1×10 4 cells / mL of BMSC cell suspension 2mL. The cells were cultured at 37°C in 5% CO2. After the cells adhered to the scaffold for 24 h, the culture medium was replaced with osteogenic induction medium (the specific composition of the osteogenic induction medium is as follows: DMEM complete medium containing 10 mmol / L sodium β-glycerophosphate, 50 μg / mL ascorbic acid, and 10 nmol / L dexamethasone, all from Sigma). The cells were cultured for 7 and 14 days, and the extract was replaced every other day. After culture, the old extract was aspirated and discarded, and the cells were washed three times with PBS. 200 μL of 0.1% Triton X-100 was added to each well and lysed at 4°C overnight. Intracellular alkaline phosphatase (ALP) activity was detected using p-NPP (Sigma). 50 μL of cell lysate was taken, 50 μL of ALP substrate reaction solution was added, and the reaction was incubated at 37°C for 30 min. The reaction was terminated by adding 50 μL of 0.1 mol / L NaOH solution. The absorbance was measured at 405 nm using a microplate reader. The total intracellular protein concentration (mg / L) was determined using a BCA kit, and the total protein mass was calculated based on the volume (50 μL) and total protein concentration. ALP activity was determined based on the absorbance value and total protein content.

[0067] The effects of pure PLGA, 10% γ-Fe2O3 and 20% γ-Fe2O3 scaffolds prepared by the present invention on the ALP activity of BMSCs under the conditions of static magnetic field stimulation and without static magnetic field stimulation are as follows: Figure 5 As shown. Figure 5 It can be seen that as the culture time increases to 14 days, the ALP activity of BMSCs increases significantly, and the porous material containing 20% nanoparticles has the highest ALP activity.

[0068] Example 6: Evaluation of the in vitro mineralization ability of a porous tissue engineering scaffold with electromagnetic response for bone repair

[0069] The scaffold prepared in Example 1 was cut into 2 mm thick block samples, and each side was sterilized by ultraviolet irradiation for 2 h. The blocks were then placed in 12-well plates and placed in a 100 mT static magnetic field. Cells were added to each well at a concentration of 1×10 4 2 mL of BMSC cell suspension was prepared at 37°C and 5% CO2. After the cells adhered to the scaffold for 24 hours, the culture medium was replaced with osteogenic induction medium (composed of complete DMEM medium containing 10 mmol / L sodium β-glycerophosphate, 50 μg / mL ascorbic acid, and 10 nmol / L dexamethasone, all from Sigma). The cells were cultured for 7 and 14 days, with fresh extracts replaced every other day. After incubation, the old extracts were discarded, the cells were washed three times with PBS, and fixed with paraformaldehyde. Calcium nodules were stained using an Alizarin Red staining kit. Excess Alizarin Red stain was then washed off with PBS. The red calcium nodule deposition was observed under a light microscope.

[0070] The effects of pure PLGA, 10% γ-Fe2O3 and 20% γ-Fe2O3 scaffolds prepared by the present invention on the osteogenic mineralization ability of BMSCs in vitro under the conditions of static magnetic field stimulation are shown in FIG. Figure 6 As shown. Figure 6 It can be seen that the number of mineralized nodules increased after the addition of nanoparticles, and the porous material containing 20% nanoparticles had the most mineralized nodules.

[0071] Example 7: Evaluation of the ability of electromagnetically responsive porous tissue engineering scaffolds for bone repair to induce HUVEC migration in vitro

[0072] The scaffold prepared in Example 1 was cut into 2 mm thick block samples, and each side was sterilized by ultraviolet irradiation for 2 h. The blocks were then placed in 12-well plates and placed in a 100 mT static magnetic field. Cells were added to each well at a concentration of 1×10 4 2 mL of HUVEC cell suspension at 100 μg / mL was cultured at 37°C with 5% CO2. After the cells adhered to the scaffold for 24 hours, the cells were scratched using a 200 μL pipette tip and the scratch morphology was observed under a microscope. The scratch morphology was observed under a microscope after another 24 hours of culture.

[0073] The results of cell scratch experiments on pure PLGA, 10% γ-Fe2O3 and 20% γ-Fe2O3 scaffolds prepared by the present invention under the conditions of static magnetic field stimulation are as follows: Figure 7 As shown. Figure 7 It can be seen that after 24 hours of culture, the migration ability of BMSCs was significantly enhanced after the addition of nanoparticles, and the cell migration rate of the porous material containing 20% nanoparticles was the fastest.

[0074] Example 8: Evaluation of the ability of electromagnetically responsive porous tissue engineering scaffolds for bone repair to induce HUVEC cell tube formation in vitro

[0075] The scaffold prepared in Example 1 was cut into 2 mm thick block samples, and each side was sterilized by ultraviolet irradiation for 2 h. The blocks were then placed in a Matrigel-coated 12-well plate and placed in a 100 mT static magnetic field. Cells were added to each well at a concentration of 1×10 4 cells / ml HUVEC cell suspension was cultured at 37°C and 5% CO2 concentration for 6 hours after the cells were co-cultured with the scaffold. The tube formation of HUVEC cells was observed under a microscope.

[0076] The tube-forming ability of HUVEC under the conditions of static magnetic field stimulation was significantly improved with pure PLGA, 10% γ-Fe2O3 and 20% γ-Fe2O3 scaffolds prepared by the present invention. Figure 8 As shown. Figure 8 It can be seen that compared with the blank control group, the tube-forming ability of the scaffold is significantly higher, and as the concentration of nanoparticles in the scaffold increases, the tube-forming ability of the scaffold also gradually increases.

[0077] Example 9: Evaluation of the ability of electromagnetically responsive porous tissue engineering scaffolds for bone repair to promote osteogenesis and angiogenesis in vivo

[0078] According to the method in Example 1, a pure PLGA and 20% γ-Fe2O3 scaffold with a diameter of 2 mm and a height of 5 mm was prepared, sterilized in an ethylene oxide environment, and aseptically packaged for use. Adult male rats were selected, anesthetized with chloral hydrate, and then the hair and skin were shaved and the distal femur was exposed. An orthopedic electric drill was used to drill a hole with a diameter of about 2.8 mm and a depth of about 8 mm, and the scaffold was implanted. At the same time, a blank control was used in which only the hole was drilled without implanting the scaffold. After the operation, the experimental rats were placed in an environment with a static magnetic field of 100 mT for breeding. The experimental animals were killed 6 and 12 weeks after implantation. The femur was separated, dehydrated, and fixed, and Micro-CT scanning was used to observe the formation of new bone around the implant.

[0079] The pure PLGA, 20% γ-Fe2O3 scaffolds prepared by the present invention and the blank control group promoted the formation of new bone and blood vessels in vivo under the condition of static magnetic field stimulation. Figure 9 As shown. Figure 9 It can be seen that compared with the implant group stimulated only by SMF, the implantation of the scaffold can significantly enhance the formation of new blood vessels and new bone in the implanted part. After 12 weeks of implantation, the affected area of the implant group containing 20% nanoparticles was basically replaced by new bone tissue, demonstrating good in vivo osteogenesis function.

[0080] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. Application of an electromagnetically responsive porous tissue engineering scaffold for bone repair and an electric field emission source and / or a magnetic field emission source in the preparation of a product for treating bone defects or bone necrosis.

2. The use according to claim 1, characterized in that: The raw materials for preparing the electromagnetic responsive porous tissue engineering scaffold for bone repair include the following components in percentage by mass: 80%-95% of polylactic acid-glycolic acid copolymer and 5%-20% of gamma-Fe2O3 nanoparticles or Fe3O4 nanoparticles.

3. The use according to claim 2, characterized in that: The particle size of the γ-Fe2O3 nanoparticles or Fe3O4 nanoparticles is 10-20 nm.

4. The use according to any one of claims 1 to 3, characterized in that: The method for preparing the porous tissue engineering scaffold with electromagnetic response for bone repair comprises the following steps: (1) mixing the polylactic acid-co-glycolic acid copolymer, γ-Fe2O3 nanoparticles or Fe3O4 nanoparticles and an organic solvent to form a homogeneous solution; (2) Using solid model design software to create a model, and exporting the data containing the model, and then using layering software to layer the data of the model to obtain layered data, and generate a corresponding format file; (3) adding the homogeneous solution of step (1) to a low-temperature rapid prototyping device, setting printing parameters according to the format file of the structure designed in step (2), and then performing printing and shaping at -40°C to -20°C to obtain a formed porous scaffold; (4) freeze-drying the formed porous scaffold to obtain the electromagnetically responsive porous tissue engineering scaffold for bone repair.

5. The use according to claim 4, characterized in that: The organic solvent is 1,4-dioxane and / or chloroform; The concentration of the poly(lactic acid-co-glycolic acid) in 1,4-dioxane is 0.05-0.5 g / mL.

6. The use according to any one of claims 1 to 5, characterized in that: The electric field emission source generates an alternating electric field or an electrostatic field; The magnetic field emission source generates an alternating magnetic field or a static magnetic field.

7. The use according to claim 6, characterized in that: The electric field strength of the alternating electric field is 0.01-10 v / cm and the frequency is 1-20 Hz; The intensity of the electrostatic field is 0.01-10v / cm; The alternating magnetic field has a magnetic field strength of 0.01-10 mT and a frequency of 1-100 Hz; The intensity of the static magnetic field is 10-200 mT.

8. A product for treating bone defects or bone necrosis, comprising a porous tissue engineering scaffold for bone repair with electromagnetic response and an electric field emission source and / or a magnetic field emission source.

9. The product according to claim 8, characterized in that: The raw materials for preparing the electromagnetic responsive porous tissue engineering scaffold for bone repair include the following components in percentage by mass: 80%-95% of polylactic acid-glycolic acid copolymer and 5%-20% of gamma-Fe2O3 nanoparticles or Fe3O4 nanoparticles.

10. The product according to claim 8 or 9, characterized in that: The electric field emission source generates an alternating electric field or an electrostatic field; The magnetic field emission source generates an alternating magnetic field or a static magnetic field.

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