A nanofiber bone regeneration membrane with sustained release of metal ions and its preparation method

Abstract

The present invention discloses a nanofiber bone regeneration membrane with sustained release of metal ions and a preparation method thereof, wherein the regeneration membrane includes a collagen fiber membrane, MOFs loaded on the collagen fiber membrane, a polycaprolactone fiber membrane on the side of the collagen fiber membrane loaded with MOFs, and a polyethylene glycol-polycaprolactone block copolymer layer on the side of the polycaprolactone layer away from the MOFs. In the present invention, the outer layer of the nanofiber bone regeneration membrane includes a polycaprolactone fiber membrane and a polyethylene glycol-polycaprolactone block copolymer layer attached to the surface of the polycaprolactone fiber membrane. The combination of the two can effectively prevent soft tissue invasion and play a good barrier role. In addition, since polycaprolactone and polyethylene glycol-polycaprolactone block copolymer are both degradable, metal ions are slowly released as polycaprolactone and polyethylene glycol-polycaprolactone block copolymer degrade, effectively avoiding the biotoxicity of high-concentration metal ions.

Description

Technical Field

[0001] The present invention relates to the technical field of medical materials, and in particular to a nanofiber bone regeneration membrane with sustained release of metal ions and a preparation method thereof. Background Art

[0002] Whether it is repairing critical bone defects, or performing extraction site preservation, periapical surgery, or guided bone regeneration, any bone defect caused by trauma or surgery, where the size of the defect exceeds the body's own repair capacity, or where better healing of the surgical area is desired, and specific technical means are needed to promote bone regeneration in the defect area, may require a guided bone regeneration barrier membrane to cover the defect area, thereby creating an environment conducive to bone regeneration. A biological barrier membrane is used to block the ingress of faster-growing epithelial cells, while providing a certain amount of space to guide the formation of slower-growing osteoblasts and blood vessels. Therefore, the biological barrier membrane is a key factor affecting bone formation in the defect area. The shortcomings of existing natural collagen barrier membranes are mainly rapid degradation, poor antibacterial properties, difficulty in obtaining raw materials, and high market prices.

[0003] Therefore, it is necessary to prepare a biological barrier membrane that has both osteoconductivity and osteoinduction, a degradation rate that matches the bone formation stage, certain antibacterial properties, and easily available preparation materials. Summary of the Invention

[0004] In order to solve the problems of rapid degradation and poor antibacterial performance of existing regeneration membranes, one of the objectives of the present invention is to provide a nanofiber bone regeneration membrane with sustained release of metal ions.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A metal ion sustained-release nanofiber bone regeneration membrane comprises a collagen fiber membrane, MOFs loaded on the collagen fiber membrane, a polycaprolactone fiber membrane located on the side of the collagen fiber membrane loaded with MOFs, and a polyethylene glycol-polycaprolactone block copolymer layer located on the side of the polycaprolactone layer away from the MOFs.

[0007] On the basis of the above technical solution, the present invention can also be improved as follows:

[0008] Furthermore, the MOFs are Zn-MOF or Cu-MOF.

[0009] A second object of the present invention is to provide a method for preparing a metal ion sustained-release nanofiber bone regeneration membrane, comprising the following steps:

[0010] Step 1: soaking the collagen fiber membrane in a percarbonate solution and then standing it to dry, and then immersing it in a mixture II containing metal ions and an organic solvent to carry out an interfacial reaction, thereby preparing a fiber membrane loaded with layered hydroxide on the collagen fiber membrane;

[0011] Step 2: Immersing the fiber membrane prepared in step 1 in a mixture III containing an organic ligand to carry out a complexation reaction to obtain a collagen fiber membrane loaded with MOFs;

[0012] Step 3, using electrospinning technology to spin a layer of polycaprolactone fiber membrane from the mixture IV containing polycaprolactone on the side of the fiber membrane with MOFs obtained in step 2 to prepare a multilayer nanofiber membrane;

[0013] Step 4: Immerse the polycaprolactone fiber membrane on one side of the composite nanofiber membrane in an acetic acid aqueous solution containing a polyethylene glycol-polycaprolactone block copolymer, then remove it and allow it to stand and dry to obtain a nanofiber bone regeneration membrane.

[0014] Furthermore, the mass fraction of carbonate in the carbonate solution in step 1 is 1 to 10 wt %, the immersion time of the collagen fiber membrane in the carbonate solution is 10 to 60 min, and the carbonate includes potassium carbonate or sodium carbonate;

[0015] The metal ion is Cu 2+ or Zn 2+ The organic solvent in mixture II is ethanol, the metal ion concentration in mixture II is less than 0.001 mol / L, and the interfacial reaction conditions in step 1 are: reaction at room temperature for 3 to 12 hours.

[0016] Furthermore, the molar concentration of the organic ligand in the mixture III in step 2 is 0.0001 to 0.001 M; the organic ligand is trimesic acid or 1,4-dimethylimidazole; and the complexation reaction time is 30 to 60 minutes.

[0017] Furthermore, the mixture IV further comprises an organic solvent; the organic solvent is hexafluoroisopropanol; and the mass fraction of the polycaprolactone in the mixture IV is 8 wt % to 10 wt %.

[0018] Furthermore, the mass fraction of the polyethylene glycol-polycaprolactone block copolymer in the acetic acid / water solution containing the polyethylene glycol-polycaprolactone block copolymer in step 4 is 0.1 to 1.0 wt %;

[0019] The immersion time of the multilayer nanofiber membrane in the acetic acid / water solution containing the polyethylene glycol-polycaprolactone block copolymer is 5 to 15 minutes.

[0020] Furthermore, the collagen fiber membrane in step 1 is prepared by electrospinning the mixture I containing collagen.

[0021] Furthermore, the mixture I in step 1 further comprises hexafluoroisopropanol, acetic acid or trifluoroethanol; and the mass fraction of collagen in the mixture I is 8 to 10 wt%.

[0022] The present invention has the following beneficial effects:

[0023] 1. The outer layer of the nanofiber bone regeneration membrane in the present invention includes a polycaprolactone fiber membrane and a polyethylene glycol-polycaprolactone block copolymer layer attached to the surface of the polycaprolactone fiber membrane. The combination of polycaprolactone and polyethylene glycol-polycaprolactone block copolymer can effectively prevent the invasion of soft tissue, play a good barrier role, and provide a certain amount of time and space for the defect area, thereby ensuring the formation of new bone.

[0024] In addition, since polycaprolactone and polyethylene glycol-polycaprolactone block copolymer are both degradable, as polycaprolactone and polyethylene glycol-polycaprolactone block copolymer degrade, the MOFs particles located in the inner layer of the nanofibrous bone regeneration membrane degrade over time and slowly release metal ions, effectively avoiding the biological toxicity of high concentrations of metal ions.

[0025] Therefore, the nanofiber bone regeneration membrane of the present invention not only has the characteristics of no biological toxicity, but also has the characteristics of good osteogenesis and antibacterial effects.

[0026] 2. The zinc ions or copper ions in the MOFs of the present invention are gradually released as polycaprolactone and polyethylene glycol-polycaprolactone block copolymer degrade. Among them, zinc ions can promote the osteogenic differentiation of bone marrow mesenchymal stem cells, regulate the function of immune cells, and inhibit bacterial growth; copper ions can promote angiogenesis. It can be seen that the biological functions of these metal ions are helpful to improve the efficiency of bone defect repair.

[0027] 3. The present invention first loads layered metal hydroxides onto collagen fiber membranes through an interfacial reaction. The layered metal hydroxides then undergo a complexation reaction with organic ligands to self-assemble into MOF particles, effectively enhancing interfacial bonding. Furthermore, the preparation method of the present invention is simple and universally applicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 are SEM images, wherein (a) is a SEM image of the nanofiber bone regeneration membrane prepared in Example 1 of the present invention, and (b) is a SEM image of the regeneration membrane prepared in Comparative Example 1. DETAILED DESCRIPTION

[0029] The following describes a metal ion sustained-release nanofiber bone regeneration membrane and its preparation method in conjunction with examples.

[0030] However, the present invention may be exemplified in many different forms and should not be construed as limited to the specific embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0031] The inventor has been deeply engaged in the field of bone regeneration membrane preparation technology and discovered that electrospinning technology can be used to prepare fibrous structures similar to extracellular matrix. The fibers can be functionalized according to needs, or carry inorganic substances, bioactive factors or chemical drugs. It is a preparation technology for multi-potential tissue engineering scaffold materials.

[0032] Metal-organic frameworks (MOFs) are crystalline materials with a periodic network structure formed by self-assembly of inorganic metal ions (or clusters) and organic ligands. They possess both the rigidity of inorganic materials and the flexibility of organic ligands, resulting in diverse sizes and shapes, large surface area and porosity, and good biocompatibility. They hold broad application prospects in the biomedical field. As the MOF framework degrades, the metal ions are slowly released.

[0033] In addition, a large number of literatures have confirmed that some metal ions can effectively promote bone tissue regeneration by regulating a series of bone formation-related cells, thereby achieving the purpose of repairing defects; such as copper ions or zinc ions, the former can promote osteogenesis and angiogenesis, and the latter can promote osteoblast proliferation and extracellular matrix mineralization, regulate immune function, and inhibit bacterial growth.

[0034] Based on this, an embodiment of the first aspect of the present invention provides a nanofiber bone regeneration membrane with sustained release of metal ions, which regeneration membrane includes a collagen fiber membrane, MOFs loaded on the collagen fiber membrane, a polycaprolactone fiber membrane located on the side of the collagen fiber membrane loaded with MOFs, and a polyethylene glycol-polycaprolactone block copolymer layer located on the side of the polycaprolactone layer away from the MOFs.

[0035] In this embodiment, the outer layer of the regeneration membrane includes a polycaprolactone fiber membrane and a polyethylene glycol-polycaprolactone block copolymer layer attached to the surface of the polycaprolactone fiber membrane. The combination of polycaprolactone and polyethylene glycol-polycaprolactone block copolymer can effectively prevent the invasion of soft tissue, play a good barrier role, and provide a certain amount of time and space for the defect area, thereby ensuring the formation of new bone.

[0036] In addition, since polycaprolactone and polyethylene glycol-polycaprolactone block copolymer are both degradable, as polycaprolactone and polyethylene glycol-polycaprolactone block copolymer degrade, the MOFs particles located in the inner layer of the nanofibrous bone regeneration membrane degrade over time and slowly release metal ions, effectively avoiding the biological toxicity of high concentrations of metal ions.

[0037] Therefore, the nanofiber bone regeneration membrane in this embodiment not only has the characteristics of no biological toxicity, but also has the characteristics of good osteogenesis and antibacterial effects.

[0038] Additionally, in some embodiments, the MOFs are Zn-MOF or Cu-MOF.

[0039] In this embodiment, the metal ions in MOFs can effectively promote bone tissue regeneration by regulating a series of bone formation-related cells, thereby achieving the purpose of repairing defects; for example, zinc ions can promote the osteogenic differentiation of bone marrow mesenchymal stem cells, regulate the function of immune cells, and inhibit bacterial growth; copper ions can promote angiogenesis; therefore, the biological functions of metal ions such as zinc ions and copper ions can help improve the efficiency of bone defect repair.

[0040] The embodiment of the second aspect of the present invention provides a method for preparing the metal ion sustained-release nanofibrous bone regeneration membrane of the embodiment of the first aspect, comprising the following steps:

[0041] Step 1, preparing a collagen fiber membrane by electrospinning a mixture I containing collagen;

[0042] Step 2: soaking the collagen fiber membrane in the carbonate solution and then standing to dry to obtain a carbonate-impregnated collagen fiber membrane; immersing the carbonate-impregnated collagen fiber membrane in a mixture II containing metal ions and an organic solvent to carry out an interfacial reaction, thereby obtaining a fiber membrane loaded with layered hydroxide on the collagen fiber membrane;

[0043] Step 3, immersing the fiber membrane prepared in step 2 in mixture III containing organic ligands to carry out complexation reaction to obtain a collagen fiber membrane loaded with MOFs;

[0044] Step 4: Using electrospinning technology, a layer of polycaprolactone fiber membrane is spun from the mixture IV containing polycaprolactone on the side of the fiber membrane with MOFs obtained in step 3 to prepare a multilayer nanofiber membrane;

[0045] Step 5: Immerse the polycaprolactone fiber membrane on one side of the multilayer nanofiber membrane in an aqueous acetic acid solution containing a polyethylene glycol-polycaprolactone block copolymer, remove it, and allow it to dry to produce a nanofiber bone regeneration membrane. In this example, a layered metal hydroxide is first loaded onto the collagen fiber membrane via an interfacial reaction. The layered metal hydroxide then undergoes a complexation reaction with an organic ligand to self-assemble into MOF particles, effectively enhancing interfacial bonding. Furthermore, the preparation method in this example is simple and universally applicable.

[0046] In addition, in some embodiments, the mixture I in step 1 further comprises hexafluoroisopropanol (HFIP), acetic acid or trifluoroethanol; the mass fraction of collagen in the mixture I is 8-10 wt %; preferably, the mass fraction of collagen in the mixture I is 8 wt %.

[0047] In addition, in this embodiment, the preparation of the collagen fiber membrane is specifically as follows: the mixture I is added to the syringe, and the collagen fiber membrane is prepared using an electrospinning device at a flow rate of 0.2 mm / min under the conditions of 15 kV positive pressure, -1 kV negative pressure, and 20 cm receiving distance, and the collagen fiber membrane prepared by spinning is placed at room temperature to allow the solvent (the solvent is hexafluoroisopropanol (HFIP), acetic acid or trifluoroethanol) to completely evaporate.

[0048] In addition, in some embodiments, the mass fraction of carbonate in the carbonate solution in step 2 is 1 to 10 wt%, and the immersion time of the collagen fiber membrane in the carbonate solution is 10 to 60 min; in this embodiment, the collagen fiber membrane is immersed in the carbonate solution under the aforementioned conditions, and after standing and drying, a fiber membrane soaked in carbonate can be obtained, which is conducive to the formation of layered hydroxides; in addition, the carbonate in this embodiment includes potassium carbonate or sodium carbonate.

[0049] The metal ion is Cu 2+ or Zn 2+ The organic solvent in mixture II is ethanol, the metal ion concentration in mixture II is less than 0.001 mol / L, and the interfacial reaction time in step 2 is 3 to 12 hours. In this embodiment, when the carbonate-loaded collagen fiber membrane is placed in mixture II, since carbonate is insoluble in ethanol, the metal ions react with the carbonate on the collagen fiber surface to form layered hydroxides, thereby improving the interfacial bonding between the MOFs and the collagen fiber membrane.

[0050] Preferably, the mixture II in this embodiment consists of metal ions and ethanol.

[0051] In some embodiments, the molar concentration of the organic ligand in Mixture III in Step 3 is 0.0001 to 0.001 M; the organic ligand is trimesic acid or 1,4-dimethylimidazole; and the complexation reaction time is 30 to 60 minutes. In this embodiment, Mixture III is prepared by dissolving the organic ligand in a mixed solvent composed of ethanol and water in a ratio of 1 to 10 by volume.

[0052] In some embodiments, mixture IV further comprises an organic solvent, wherein the organic solvent is hexafluoroisopropanol. The mass fraction of polycaprolactone in mixture IV is 8 wt % to 10 wt %. Preferably, in this embodiment, mixture IV is obtained by dissolving polycaprolactone in hexafluoroisopropanol and stirring at room temperature for 6 hours.

[0053] In addition, the preparation of the polycaprolactone fiber membrane in this embodiment specifically includes the following steps:

[0054] The mixture IV was added to the syringe, and the polycaprolactone fiber membrane was prepared using an electrospinning device at a flow rate of 0.2 mm / min under the conditions of 15 kV positive pressure, -1 kV negative pressure, and 20 cm receiving distance; during spinning, the spinning was performed on the MOFs-containing side of the MOFs-loaded collagen fiber membrane.

[0055] In some embodiments, the mass fraction of the polyethylene glycol-polycaprolactone block copolymer in the acetic acid / water solution containing the polyethylene glycol-polycaprolactone block copolymer in step 5 is 0.1 to 1.0 wt %, and the multilayer nanofiber membrane is immersed in the acetic acid / water solution containing the polyethylene glycol-polycaprolactone block copolymer for 5 to 15 minutes. In this embodiment, the acetic acid solution can prepare a supersaturated solution of the polyethylene glycol-polycaprolactone block copolymer while also preventing the acetic acid solution from damaging the fiber membranes in the multilayer nanofiber membrane.

[0056] Example

[0057] Example 1

[0058] A method for preparing a metal ion sustained-release nanofiber bone regeneration membrane comprises the following steps:

[0059] Step 1. First, dissolve collagen in hexafluoroisopropanol and stir at room temperature to obtain a mixture I solution with a collagen mass fraction of 8 wt%; then add the mixture I solution into a syringe, and use an electrospinning device to spin at a flow rate of 0.2 mm / min under the conditions of 15 kV positive pressure, -1 kV negative pressure, and 20 cm receiving distance to obtain a collagen fiber membrane, and let it stand at room temperature to allow the solvent to completely evaporate.

[0060] Step 2: Cut the collagen fiber membrane in step 1 into blocks of 5×5 cm in size and immerse it in 50 mL of a potassium carbonate aqueous solution with a mass fraction of 5 wt% potassium carbonate, and vibrate it on a circular shaker at 100 rpm for 30 minutes; then take out the collagen fiber membrane, drain the water, and let it stand to dry for 12 hours. Then, soak the dried fiber collagen membrane in 50 mL of a copper nitrate ethanol solution with a molar concentration of 0.001 M for 3 hours to perform an interfacial reaction. After the reaction is completed, wash with deionized water to remove the unreacted potassium carbonate and let it stand to dry for 12 hours to obtain a fiber membrane loaded with layered hydroxide on the collagen fiber membrane.

[0061] Step 3. Immerse the fiber membrane loaded with layered hydroxide in step 2 in 50 mL of mixture III for a complex reaction for 1 hour to convert all the layered metal hydroxides into Cu-MOFs particles, wherein mixture III is prepared by dissolving trimesic acid in a mixed solvent of ethanol and water with a volume ratio of 99:1, and the molar concentration of trimesic acid in mixture III is 0.001 M; after the complex reaction is completed, the product is washed with ethanol to remove unreacted trimesic acid, and then allowed to stand and dry for 6 hours to obtain a collagen fiber membrane loaded with Cu-MOFs.

[0062] Step 4: Dissolve 0.7 g of polycaprolactone in 5 mL of hexafluoroisopropanol and stir at room temperature for 6 hours to obtain a mixture IV, then add the mixture IV into a 10 mL syringe, and use an electrospinning device to spin a layer of polycaprolactone fiber membrane on the side of the collagen fiber membrane with Cu-MOFs particles obtained in step 3. After the electrospinning is completed, dry and remove the hexafluoroisopropanol to obtain a multilayer nanofiber membrane; wherein, the drying conditions are: 12 hours in a vacuum oven at 45°C, and the electrospinning conditions are: 15 kV positive pressure, -1 kV negative pressure, 20 cm receiving distance, and spinning at a flow rate of 0.2 mm / min.

[0063] Step 5: Dissolve 0.25 g of polycaprolactone-polyethylene glycol block copolymer in 50 mL of acetic acid aqueous solution and stir at 50°C (wherein the acetic acid aqueous solution is composed of acetic acid and water in a volume ratio of 77:23). Then, immerse the polycaprolactone fiber membrane on one side of the multilayer nanofiber membrane prepared in step 4 in the acetic acid aqueous solution containing polyethylene glycol-polycaprolactone block copolymer at room temperature for 10 minutes, then remove it and let it stand at room temperature for 12 hours. Wait until the solution is completely evaporated to finally obtain the nanofiber bone regeneration membrane.

[0064] Example 2

[0065] A method for preparing a metal ion sustained-release nanofiber bone regeneration membrane comprises the following steps:

[0066] Step 1. First, dissolve collagen in hexafluoroisopropanol and stir at room temperature to obtain a mixture I solution with a collagen mass fraction of 8 wt%; then add the mixture I solution into a syringe, and use an electrospinning device to spin at a flow rate of 0.2 mm / min under the conditions of 15 kV positive pressure, -1 kV negative pressure, and 20 cm receiving distance to obtain a collagen fiber membrane, and let it stand at room temperature to allow the solvent to completely evaporate.

[0067] Step 2: Cut the collagen fiber membrane in step 1 into blocks of 5×5 cm in size and immerse it in 50 mL of a potassium carbonate aqueous solution with a mass fraction of 5 wt% potassium carbonate, and vibrate it on a circular shaker at 100 rpm for 30 minutes; then take out the collagen fiber membrane, drain the water, and let it stand to dry for 12 hours. Then, soak the dried fiber collagen membrane in 50 mL of a zinc acetate ethanol solution with a molar concentration of 0.001 M for 3 hours to perform an interfacial reaction. After the reaction is completed, wash with deionized water to remove the unreacted potassium carbonate and let it stand to dry for 12 hours to obtain a fiber membrane loaded with layered hydroxide on the collagen fiber membrane.

[0068] Step 3. Immerse the fiber membrane loaded with layered hydroxide in step 2 in 50 mL of mixture III for complex reaction for 1 hour to convert all the layered metal hydroxides into Zn-MOFs particles. Mixture III is prepared by dissolving 1,4-dimethylimidazole in a mixed solvent of ethanol and water with a volume ratio of 99:1, and the molar concentration of 1,4-dimethylimidazole in mixture III is 0.001M; after the complex reaction is completed, the product is washed with ethanol to remove unreacted 1,4-dimethylimidazole, and allowed to stand and dry for 6 hours to obtain a collagen fiber membrane loaded with Zn-MOFs.

[0069] Step 4: Dissolve 0.8 g of polycaprolactone in 5 mL of hexafluoroisopropanol and stir at room temperature for 6 hours to obtain a mixture IV, then add the mixture IV into a 10 mL syringe, and use an electrospinning device to spin a layer of polycaprolactone fiber membrane on the side of the collagen fiber membrane with Zn-MOFs particles obtained in step 3. After the electrospinning is completed, dry and remove the hexafluoroisopropanol to obtain a multilayer nanofiber membrane; wherein, the drying conditions are: 12 hours in a vacuum oven at 45°C, and the electrospinning conditions are: 15 kV positive pressure, -1 kV negative pressure, 20 cm receiving distance, and spinning at a flow rate of 0.2 mm / min.

[0070] Step 5: Dissolve 0.25 g of polycaprolactone-polyethylene glycol block copolymer in 50 mL of acetic acid aqueous solution and stir at 50°C (wherein the acetic acid aqueous solution is composed of acetic acid and water in a volume ratio of 77:23). Then, immerse the multilayer nanofiber membrane prepared in step 4 in the acetic acid aqueous solution containing polyethylene glycol-polycaprolactone block copolymer at room temperature for 15 minutes, then take it out and let it stand at room temperature for 12 hours. Wait until the solution is completely evaporated to finally obtain the nanofiber bone regeneration membrane.

[0071] Example 3

[0072] The preparation method of a metal ion sustained-release nanofibrous bone regeneration membrane in this embodiment is the same as that in Example 1, except that:

[0073] In step 1, the mass fraction of collagen in mixture I is 10 wt%;

[0074] The mass fraction of potassium carbonate in the potassium carbonate solution in step 2 is 1 wt %, and the collagen fiber membrane is immersed in the potassium carbonate solution for 10 min (i.e., vibrated on a 100 rpm orbital shaker for 10 min); the molar concentration of copper nitrate in mixture II is 0.0002 mol / L, and the interfacial reaction time in step 2 is 6 h.

[0075] The molar concentration of trimesic acid in mixture III in step 3 is 0.0001 M; and the complexation reaction time is 30 min.

[0076] The mass fraction of polycaprolactone in mixture IV in step 4 is 8 wt %.

[0077] The mass fraction of the polyethylene glycol-polycaprolactone block copolymer in the acetic acid / water solution containing the polyethylene glycol-polycaprolactone block copolymer in step 5 is 0.1 wt %; the immersion time of the multilayer nanofiber membrane in the acetic acid / water solution containing the polyethylene glycol-polycaprolactone block copolymer is 5 min.

[0078] Example 4

[0079] The preparation method of a metal ion sustained-release nanofibrous bone regeneration membrane in this embodiment is the same as that in Example 1, except that:

[0080] The mass fraction of potassium carbonate in the potassium carbonate solution in step 2 is 10 wt %, and the collagen fiber membrane is immersed in the potassium carbonate solution for 60 min (i.e., vibrated on an orbital shaker at 100 rpm for 60 min); the molar concentration of copper nitrate in mixture II is 0.0008 mol / L, and the interfacial reaction time in step 2 is 12 h.

[0081] The mass fraction of polycaprolactone in the mixture IV in step 4 is 10 wt %.

[0082] The mass fraction of the polyethylene glycol-polycaprolactone block copolymer in the acetic acid / water solution containing the polyethylene glycol-polycaprolactone block copolymer in step 5 is 1.0 wt %; the immersion time of the multilayer nanofiber membrane in the acetic acid / water solution containing the polyethylene glycol-polycaprolactone block copolymer is 15 min.

[0083] Comparative Example 1

[0084] The preparation method of a metal ion sustained-release nanofibrous bone regeneration membrane in this embodiment is the same as that in Example 1, except that the obtained collagen membrane is directly immersed in a solution containing Cu-MOFs for 30 minutes.

[0085] Comparative Example 2

[0086] A method for preparing a nanofiber bone regeneration membrane comprises the following steps:

[0087] Step 1. First, dissolve collagen in hexafluoroisopropanol and stir at room temperature to obtain a mixture I solution with a collagen mass fraction of 8 wt%; then add the mixture I solution into a syringe, and use an electrospinning device to spin at a flow rate of 0.2 mm / min under the conditions of 15 kV positive pressure, -1 kV negative pressure, and 20 cm receiving distance to obtain a collagen fiber membrane, and let it stand at room temperature to allow the solvent to completely evaporate.

[0088] Step 2: Cut the collagen fiber membrane in step 1 into blocks of 5×5 cm in size and immerse them in 50 mL of a 5 wt% potassium carbonate aqueous solution and vibrate on a circular shaker at 100 rpm for 30 minutes; then take out the collagen fiber membrane, drain the water, and let it stand to dry for 12 hours. Then, soak the dried fiber collagen membrane in 50 mL of a copper nitrate ethanol solution with a molar concentration of 0.001 M for 3 hours to perform an interfacial reaction. After the reaction is completed, wash with deionized water to remove the unreacted potassium carbonate and let it stand to dry to obtain a fiber membrane loaded with layered hydroxide on the collagen fiber membrane.

[0089] Step 3. Immerse the fiber membrane loaded with layered hydroxide in step 2 in 50 mL of mixture III for a complex reaction for 1 hour to convert all the layered metal hydroxides into Cu-MOFs particles, wherein mixture III is prepared by dissolving trimesic acid in a mixed solvent of ethanol and water with a volume ratio of 99:1; after the reaction is completed, the product is washed with ethanol to remove unreacted trimesic acid, and allowed to stand and dry for 6 hours to obtain a collagen fiber membrane loaded with Cu-MOFs.

[0090] Test analysis:

[0091] The regenerated membranes prepared in Example 1 and Comparative Example 1 were subjected to SEM testing, and the test results are shown in Figure 1 .from Figure 1 It can be seen that soaking the collagen fiber membrane in carbonate is more conducive to loading MOFs on the collagen fiber membrane.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A metal ion sustained-release nanofiber bone regeneration membrane, characterized in that: The invention comprises a collagen fiber membrane, MOFs loaded on the collagen fiber membrane, a polycaprolactone fiber membrane located on the side of the collagen fiber membrane loaded with MOFs, and a polyethylene glycol-polycaprolactone block copolymer layer located on the side of the polycaprolactone fiber membrane away from the MOFs; The method for preparing the metal ion sustained-release nanofiber bone regeneration membrane comprises the following steps: Step 1: soaking the collagen fiber membrane in a percarbonate solution and then standing it to dry, and then immersing it in a mixture II containing metal ions and an organic solvent to carry out an interfacial reaction, thereby preparing a fiber membrane loaded with layered hydroxide on the collagen fiber membrane; Step 2: Immersing the fiber membrane prepared in step 1 in a mixture III containing an organic ligand to carry out a complexation reaction to obtain a collagen fiber membrane loaded with MOFs; Step 3, using electrospinning technology to spin a layer of polycaprolactone fiber membrane from the mixture IV containing polycaprolactone on the side of the fiber membrane with MOFs obtained in step 2 to prepare a multilayer nanofiber membrane; Step 4, immersing the polycaprolactone fiber membrane on one side of the multilayer nanofiber membrane in an acetic acid aqueous solution containing polyethylene glycol-polycaprolactone block copolymer, then removing the membrane and standing it to dry to obtain a nanofiber bone regeneration membrane; The MOFs are Zn-MOF or Cu-MOF.

2. The nanofiber bone regeneration membrane according to claim 1, characterized in that The mass fraction of carbonate in the carbonate solution in step 1 is 1-10 wt %, the immersion time of the collagen fiber membrane in the carbonate solution is 10-60 min, and the carbonate includes potassium carbonate or sodium carbonate; The metal ion is Cu 2+ or Zn 2+ The organic solvent in the mixture II is ethanol, the metal ion concentration in the mixture II is less than 0.001 mol / L, and the interfacial reaction conditions in step 1 are: reaction at room temperature for 3 to 12 hours.

3. The nanofiber bone regeneration membrane according to claim 1, characterized in that The molar concentration of the organic ligand in the mixture III in step 2 is 0.0001-0.001 M; the organic ligand is trimesic acid or 1,4-dimethylimidazole; and the complexation reaction time is 30-60 min.

4. The nanofiber bone regeneration membrane according to claim 1, characterized in that The mixture IV further includes an organic solvent; the organic solvent is hexafluoroisopropanol; and the mass fraction of polycaprolactone in the mixture IV is 8 wt % to 10 wt %.

5. The nanofiber bone regeneration membrane according to claim 1, characterized in that The mass fraction of the polyethylene glycol-polycaprolactone block copolymer in the acetic acid aqueous solution containing the polyethylene glycol-polycaprolactone block copolymer in step 4 is 0.1-1.0 wt %; The multilayer nanofiber membrane is immersed in the acetic acid aqueous solution containing the polyethylene glycol-polycaprolactone block copolymer for 5 to 15 minutes.

6. The nanofiber bone regeneration membrane according to claim 1, characterized in that The collagen fiber membrane in step 1 is prepared by electrospinning a mixture I containing collagen.

7. The nanofiber bone regeneration membrane according to claim 6, characterized in that The mixture I in step 1 further comprises hexafluoroisopropanol, acetic acid or trifluoroethanol; the mass fraction of collagen in the mixture I is 8-10 wt%.

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