A mechanically reinforced integrated three-dimensional micro / nanofiber scaffold and its fabrication method

Abstract

This invention belongs to the field of biomedical materials technology and discloses a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold and its preparation method. The invention involves electrospinning hydrophilic and hydrophobic polymer materials to obtain micro / nanofiber membranes, then foaming them using a sol-containing foaming solution to obtain a three-dimensional micro / nanofiber scaffold. The scaffold is then filled with sol and freeze-dried to obtain a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold. The three-dimensional micro / nanofiber material and the freeze-dried scaffold form a continuous, integrated interpenetrating network structure with good integrity, resistance to delamination, and significantly enhanced mechanical properties. It also exhibits superior and controllable surface post-processing characteristics, especially the bifacial anisotropic treatment, which allows for convenient and quick at imparting multifunctionality to the scaffold. Furthermore, the thickness can be flexibly and conveniently adjusted through pressing during application to meet different medical needs.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, and in particular to a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold and its preparation method. Background Technology

[0002] Three-dimensional micro / nanofiber scaffolds possess characteristics such as high porosity, water absorption, permeability, high specific surface area, and a structure similar to the extracellular matrix. They have great potential and broad prospects in the biomedical field, such as tissue engineering scaffolds, guided bone regeneration membranes, and periodontal ligaments.

[0003] Most existing electrospun three-dimensional micro / nanofiber scaffolds are obtained by extending the spinning time and continuously stacking nanofibers. This method has drawbacks such as low preparation efficiency, easy delamination of the scaffolds, and difficulty in improving porosity. While preparing three-dimensional micro / nanofiber scaffolds through layer-by-layer stacking of fiber membranes can overcome the aforementioned drawback of difficulty in improving porosity, the problems of low preparation efficiency and easy delamination between membranes still exist.

[0004] Gas foaming is a simple and efficient technique for fabricating three-dimensional scaffolds, rapidly expanding micro / nanofiber membranes into three-dimensional micro / nanofiber scaffolds. It offers advantages such as low cost and ease of operation, and has attracted widespread attention in recent years. However, practical experience has shown that three-dimensional micro / nanofiber scaffolds obtained through gas foaming still suffer from problems such as low mechanical properties, easy delamination, loose fiber stacking, and poor shape retention. Furthermore, post-processing is challenging, making it difficult to perform anisotropic functionalization, resulting in gas-foamed three-dimensional scaffolds with limited functional levels and restricting their application range. Summary of the Invention

[0005] The purpose of this invention is to provide a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold and its preparation method, thereby solving the aforementioned problems of existing three-dimensional micro / nanofiber scaffolds obtained from gas-foamed micro / nanofiber membranes.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] This invention provides a method for fabricating a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold, comprising the following steps:

[0008] A hydrophobic medical polymer material, a hydrophilic medical polymer material, and a solvent are mixed to obtain a spinning solution; the spinning solution is then electrospun to obtain a micro / nanofiber membrane.

[0009] The micro-nanofiber membrane was foamed with a foaming liquid to obtain a three-dimensional micro-nanofiber scaffold.

[0010] A three-dimensional micro / nanofiber scaffold was injected with sol-filled material B and then freeze-dried to obtain a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold.

[0011] The foaming solution includes sol A and sodium borohydride; sol A includes one or more of gelatin sol, gelMA sol, and hyaluronic acid sol.

[0012] The sol B includes one or more of gelatin sol, gelMA sol, silk fibroin sol, hyaluronic acid sol, and chitosan sol.

[0013] Preferably, in the above-mentioned method for preparing a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold, the hydrophobic medical polymer material includes one or more of polycaprolactone, polylactic acid, poly-L-lactic acid, poly-D-lactic acid, polylactic acid-glycolic acid copolymer, and poly-L-lactide-caprolactone; the hydrophilic medical polymer material includes one or more of collagen, gelatin, silk fibroin, chitosan, hyaluronic acid, polyvinyl alcohol, polyethylene glycol, and polyethylene oxide.

[0014] Preferably, in the above-mentioned method for preparing an integrated three-dimensional micro / nanofiber scaffold with enhanced mechanical strength, the electrospinning parameters are as follows: spinning voltage of 17–20 kV; spinning distance of 12–16 cm; injection speed of 1–1.5 mL / h; needle type of 21–24 G; and receiving roller speed of 100–500 rpm.

[0015] Preferably, in the above-mentioned method for preparing an integrated three-dimensional micro / nanofiber scaffold with mechanical reinforcement, the mass concentration of sol A is 0.01–5%; and the concentration of sodium borohydride in the foaming solution is 0.1–1 mol / L.

[0016] Preferably, in the above-mentioned method for preparing an integrated three-dimensional micro / nanofiber scaffold with mechanical reinforcement, the foaming time is 10-60 min.

[0017] Preferably, in the above-mentioned method for preparing an integrated three-dimensional micro / nanofiber scaffold with enhanced mechanical strength, the mass concentration of the sol B is 0.1-20%.

[0018] Preferably, in the above-mentioned method for preparing a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold, the injection filling method is as follows: sol B is drawn using a syringe and injected into the three-dimensional micro / nanofiber scaffold; the volume ratio of sol B to the volume of the three-dimensional micro / nanofiber scaffold is 1-5 mL: 1-4 cm³. 3 .

[0019] Preferably, in the above-mentioned method for preparing an integrated three-dimensional micro / nanofiber scaffold with enhanced mechanical strength, the freeze-drying includes freezing and lyophilization; the freezing temperature is -20°C; the freezing time is 12 to 16 hours; the lyophilization temperature is -50 to -80°C; and the lyophilization time is 24 to 48 hours.

[0020] The present invention also provides a method for preparing a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold.

[0021] The present invention also provides an application of a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold in biomedical materials.

[0022] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The mechanically enhanced integrated three-dimensional micro-nanofiber scaffold of the present invention forms a continuous integrated interpenetrating network structure with three-dimensional micro-nanofiber material and freeze-dried scaffold, which has good integrity and is not easy to delaminate. Compared with the three-dimensional micro-nanofiber scaffold prepared by traditional gas foaming, the mechanical properties are significantly enhanced.

[0024] (2) The freeze-dried porous scaffold formed by sol-filling in this invention enhances the mechanical properties and barrier properties of the three-dimensional micro / nanofiber material, making the overall structure of the material more stable and less prone to delamination. It also has superior and controllable surface post-processing characteristics, especially the bi-sided anisotropic treatment, which can conveniently and quickly endow the scaffold with multifunctionality. This solves the problem that traditional gas-foamed scaffolds are difficult to bi-sided anisotropic treatment due to their low mechanical properties, thus expanding the application range. At the same time, the thickness can be flexibly and conveniently adjusted by pressing during application to meet different medical needs.

[0025] (3) This invention adds a sol to the foaming solution, which on the one hand optimizes the foaming medium. The sol effectively dissolves and uniformly disperses sodium borohydride, and through its inherent viscosity and stability, optimizes the formation and stability of bubbles, thereby ensuring the uniformity of the pore structure and mechanical properties of the three-dimensional scaffold. On the other hand, it can control the foaming process. By precisely controlling the concentration of the sol, the decomposition rate of sodium borohydride can be controlled, ensuring the controllability and stability of the pore structure of the three-dimensional scaffold. The polymer molecules in the sol and the two-dimensional fiber membrane initially form a three-dimensional network structure through physical interaction or chemical bonding. As the foaming process proceeds, the expansion and stabilization of the bubbles further enhance this physical or chemical bond, providing initial mechanical support for the scaffold.

[0026] (4) The present invention adopts a preparation method of electrospinning, gas foaming, sol injection and freeze drying, which is simple to operate, short process and low cost, and is suitable for mass production. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0028] Figure 1 This is a schematic diagram of the fabrication process of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffold of the present invention;

[0029] Figure 2 The image shows the appearance of the micro / nanofiber membrane obtained in step (1) of Example 1.

[0030] Figure 3 This is an external view of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffold prepared in Example 1.

[0031] Figure 4 This is an image of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffold prepared in Example 1 after compression.

[0032] Figure 5 The image is a scanning electron microscope image of the micro / nanofiber membrane obtained in step (1) of Example 1.

[0033] Figure 6 This is a scanning electron microscope image of the upper surface of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffold prepared in Example 1;

[0034] Figure 7 This is a scanning electron microscope image of the interior of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffold prepared in Example 1.

[0035] Figure 8 The image shows the appearance of the three-dimensional micro / nanofiber scaffold prepared in Comparative Example 1.

[0036] Figure 9 The image shows the appearance of the three-dimensional micro / nanofiber scaffold prepared in Comparative Example 2.

[0037] Figure 10 The image shows a scanning electron microscope (SEM) image of the upper surface of the three-dimensional micro / nanofiber scaffold prepared in Comparative Example 1.

[0038] Figure 11 The image shows a scanning electron microscope (SEM) image of the upper surface of the three-dimensional micro / nanofiber scaffold prepared in Comparative Example 2.

[0039] Figure 12 The diagram shows the compressive stress-strain results of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffolds prepared in Examples 1-2 and the three-dimensional micro / nanofiber scaffolds prepared in Comparative Examples 1-2.

[0040] Figure 13The figures show the compression modulus results of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffolds prepared in Examples 1-2 and the three-dimensional micro / nanofiber scaffolds prepared in Comparative Examples 1-2. Detailed Implementation

[0041] This invention provides a method for fabricating a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold, the fabrication process of which is illustrated in the schematic diagram below. Figure 1 As shown, it includes the following steps:

[0042] A hydrophobic medical polymer material, a hydrophilic medical polymer material, and a solvent are mixed to obtain a spinning solution; the spinning solution is then electrospun to obtain a micro / nanofiber membrane.

[0043] The micro-nanofiber membrane was foamed with a foaming liquid to obtain a three-dimensional micro-nanofiber scaffold.

[0044] A three-dimensional micro / nanofiber scaffold was injected with sol-filled material B and then freeze-dried to obtain a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold.

[0045] In this invention, the hydrophobic medical polymer material preferably includes one or more of polycaprolactone (PCL), polylactic acid (PLA), poly-L-lactic acid (PLLA), poly-D-lactic acid (PDLA), polylactic acid-glycolic acid copolymer (PLGA), and poly-L-lactide-caprolactone (PLCL), more preferably one or more of PCL, PLA, and PLGA, and even more preferably PCL.

[0046] In this invention, the hydrophilic medical polymer material preferably includes one or more of collagen, gelatin, silk fibroin, chitosan, hyaluronic acid, polyvinyl alcohol (PVA), polyethylene glycol (PEG), and polyethylene oxide (PEO), more preferably one or more of gelatin, silk fibroin, hyaluronic acid, and PVA, and more preferably gelatin.

[0047] In this invention, the solvent preferably includes one or more of hexafluoroisopropanol, dichloromethane, and trichloromethane, more preferably hexafluoroisopropanol or dichloromethane, and even more preferably hexafluoroisopropanol.

[0048] In this invention, the mass ratio of the hydrophobic medical polymer material to the hydrophilic medical polymer material is preferably 0-99:1-100, more preferably 2-30:1-20, and even more preferably 4:1.

[0049] In this invention, the total mass concentration of the hydrophobic medical polymer material and the hydrophilic medical polymer material in the spinning solution is preferably 0.08-0.12 g / mL, more preferably 0.09-0.11 g / mL, and even more preferably 0.1 g / mL.

[0050] In this invention, the parameters of the electrospinning are as follows: the spinning voltage is preferably 17-20 kV, more preferably 19-20 kV, and even more preferably 20 kV; the spinning distance is preferably 12-16 cm, more preferably 14-16 cm, and even more preferably 16 cm; the injection speed is preferably 1-1.5 mL / h, more preferably 1.2-1.5 mL / h, and even more preferably 1.5 mL / h; the needle type is preferably 21-24G, more preferably 21-23G, and even more preferably 21G; the receiving roller speed is preferably 100-500 rpm, more preferably 200-400 rpm, and even more preferably 300 rpm.

[0051] In this invention, the electrospinning process is further followed by vacuum drying at 37°C for 24 hours after completion.

[0052] In this invention, the foaming liquid preferably includes sol A and sodium borohydride.

[0053] In this invention, the sol A preferably includes one or more of gelatin sol, gelMA sol, and hyaluronic acid sol, more preferably gelatin sol or hyaluronic acid sol, and even more preferably gelatin sol.

[0054] In this invention, the mass concentration of sol A is preferably 0.01-5%, more preferably 1-5%, and even more preferably 5%.

[0055] In this invention, the concentration of sodium borohydride in the foaming liquid is preferably 0.1 to 1 mol / L, more preferably 0.4 to 0.7 mol / L, and even more preferably 0.5 mol / L.

[0056] In this invention, the foaming time is preferably 10 to 60 minutes, more preferably 12 to 30 minutes, and even more preferably 15 minutes.

[0057] In this invention, the foaming process is further complicated by water washing.

[0058] In this invention, the injection filling method is as follows: sol B is drawn out using a syringe and then injected into a three-dimensional micro / nanofiber scaffold; the syringe needle is preferably 18-25G, more preferably 20-24G, and even more preferably 22G.

[0059] In this invention, the volume ratio of sol B to the volume of the three-dimensional micro / nanofiber scaffold is preferably 1-5 mL: 1-4 cm. 3 A further preferred ratio is 1-2 mL: 3-4 cm 3 More preferably, the ratio is 1 mL: 4 cm 3 .

[0060] In this invention, the sol B preferably includes one or more of gelatin sol, GelMA sol, silk fibroin sol, hyaluronic acid sol, and chitosan sol, more preferably one or more of gelatin sol, hyaluronic acid sol, and chitosan sol, and more preferably gelatin sol.

[0061] In this invention, the mass concentration of sol B is preferably 0.1-20%, more preferably 5-15%, and even more preferably 10%.

[0062] In this invention, the freeze-drying includes freezing and freeze-drying; the freezing temperature is preferably -20°C; the freezing time is preferably 12-16 hours, more preferably 12-14 hours, and even more preferably 12 hours; the freeze-drying temperature is preferably -50-80°C, more preferably -60-80°C, and even more preferably -80°C; the freeze-drying time is preferably 24-48 hours, more preferably 28-45 hours, and even more preferably 40 hours.

[0063] The present invention also provides a method for preparing a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold.

[0064] The present invention also provides an application of a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold in biomedical materials.

[0065] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0066] Example 1

[0067] This embodiment provides a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold, the preparation method of which includes the following steps:

[0068] (1) Weigh 1.6g PCL (molecular weight 80,000) and 0.4g gelatin (derived from pigskin) and dissolve them in 20mL of hexafluoroisopropanol (HFIP) to obtain a uniformly dispersed PCL / Gel spinning solution with a total mass concentration of 0.1g / mL; divide 20mL of PCL / Gel spinning solution into two 10mL syringes and perform electrospinning by spraying back and forth; set the electrospinning parameters as follows: spinning voltage 20kV, spinning distance 16cm, injection speed 1.5mL / h, needle type 21G, receiving roller speed 300rpm; vacuum dry the collected membrane at 37℃ for 24h to obtain micro / nanofiber membrane;

[0069] (2) Weigh 2.5g of gelatin and dissolve it in 50mL of ultrapure water. Stir magnetically at 40℃ for 30min to fully dissolve the gelatin. Then cool at room temperature for 1h to obtain a gelatin sol with a mass concentration of 5%. Add sodium borohydride to the gelatin sol to make its concentration 0.5mol / L to obtain a foaming solution. Place the micro / nanofiber membrane in the foaming solution and foam for 15min. Then take it out and rinse it three times with deionized water to remove residual sodium borohydride to obtain a three-dimensional micro / nanofiber scaffold.

[0070] (3) Weigh 5g of gelatin and dissolve it in 50mL of ultrapure water. Stir magnetically at 40℃ for 30min to fully dissolve the gelatin, then cool at room temperature for 1h to obtain a gelatin sol with a mass concentration of 10%. Use a 22G syringe to draw 1mL of the gelatin sol and inject it into a 4cm³ volume. 3 The three-dimensional micro / nanofiber scaffold was filled with the scaffold and then frozen in a -20°C freezer for 16 hours. It was then transferred to a vacuum freeze dryer and freeze-dried at -80°C for 40 hours to obtain a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold.

[0071] The appearance of the micro / nanofiber membrane obtained in step (1) of Example 1 is shown in the figure. Figure 2 As shown, by Figure 2 It can be seen that the thickness of the micro / nanofiber membrane obtained by electrospinning is in the range of 150–200 μm.

[0072] The appearance of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffold prepared in Example 1 is shown in the figure below. Figure 3 As shown, the appearance after pressing is as follows: Figure 4 As shown. Figure 3 and Figure 4 It is known that the thickness of the integrated three-dimensional micro-nanofiber scaffold can reach 1cm, and the thickness can be as low as 1mm after compression. When applied, the thickness can be flexibly and conveniently adjusted by compression to meet different medical needs.

[0073] The scanning electron microscope image of the micro / nanofiber membrane obtained in step (1) of Example 1 is shown below. Figure 5 As shown, scanning electron microscope (SEM) images of the upper surface and interior of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffold prepared in Example 1 are shown below. Figure 6 and Figure 7 As shown. Figures 5-7 It can be seen that the three-dimensional micro / nanofiber material and the freeze-dried scaffold form a continuous, integrated interpenetrating network structure with good integrity and is not easily delaminated.

[0074] Example 2

[0075] This embodiment provides a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold, the preparation method of which includes the following steps:

[0076] (1) Weigh 1.2g PCL (molecular weight 80,000) and 0.8g gelatin (derived from pigskin) and dissolve them in 20mL of hexafluoroisopropanol (HFIP) to obtain a uniformly dispersed PCL / Gel spinning solution with a total mass concentration of 0.1g / mL; divide 20mL of PCL / Gel spinning solution into two 10mL syringes and perform electrospinning by spraying back and forth; set the electrospinning parameters as follows: spinning voltage 20kV, spinning distance 16cm, injection speed 1.5mL / h, needle type 22G, receiving roller speed 500rpm; vacuum dry the collected membrane at 37℃ for 24h to obtain micro / nanofiber membrane;

[0077] (2) Weigh 2.5g of gelatin and dissolve it in 50mL of ultrapure water. Stir magnetically at 40℃ for 30min to fully dissolve the gelatin. Then cool at room temperature for 1h to obtain a gelatin sol with a mass concentration of 5%. Add sodium borohydride to the gelatin sol to make its concentration 0.5mol / L to obtain a foaming solution. Place the micro / nanofiber membrane in the foaming solution and foam for 10min. Then take it out and rinse it three times with deionized water to remove residual sodium borohydride to obtain a three-dimensional micro / nanofiber scaffold.

[0078] (3) Weigh 2.5g of gelatin and dissolve it in 50mL of ultrapure water. Stir magnetically at 40℃ for 30min to fully dissolve the gelatin, then cool at room temperature for 1h to obtain a gelatin sol with a mass concentration of 5%. Use a 25G syringe to draw 1mL of the gelatin sol and inject it into a 4cm³ volume. 3 The three-dimensional micro / nanofiber scaffold was filled with the scaffold and then frozen in a -20°C freezer for 16 hours. It was then transferred to a vacuum freeze dryer and freeze-dried at -80°C for 40 hours to obtain a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold.

[0079] Example 3

[0080] This embodiment provides a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold, the preparation method of which includes the following steps:

[0081] (1) Weigh 1.92g PCL (molecular weight 80,000) and 0.48g gelatin (Gel, derived from pigskin) and dissolve them in 20mL of hexafluoroisopropanol (HFIP) to obtain a uniformly dispersed PCL / Gel spinning solution with a total mass concentration of 0.12g / mL; divide 20mL of PCL / Gel spinning solution into two 10mL syringes and perform electrospinning by spraying back and forth; set the electrospinning parameters as follows: spinning voltage 20kV, spinning distance 16cm, injection speed 1.5mL / h, needle type 21G, receiving roller speed 400rpm; dry the collected membrane under vacuum at 37℃ for 24h to obtain micro / nanofiber membrane;

[0082] (2) Weigh 2.5g of gelatin and dissolve it in 50mL of ultrapure water. Stir magnetically at 40℃ for 30min to fully dissolve the gelatin. Then cool at room temperature for 1h to obtain a gelatin sol with a mass concentration of 5%. Add sodium borohydride to the gelatin sol to make its concentration 0.5mol / L to obtain a foaming solution. Place the micro / nanofiber membrane in the foaming solution and foam for 10min. Then take it out and rinse it three times with deionized water to remove residual sodium borohydride to obtain a three-dimensional micro / nanofiber scaffold.

[0083] (3) Weigh 0.1g of hyaluronic acid and dissolve it in 10mL of ultrapure water. Stir magnetically at room temperature for 24h to obtain a hyaluronic acid sol with a mass concentration of 1%. Use an 18G syringe to draw 1mL of the hyaluronic acid sol and inject it into a 4cm³ volume. 3 The three-dimensional micro / nanofiber scaffold was filled with the scaffold and then frozen in a -20°C freezer for 16 hours. It was then transferred to a vacuum freeze dryer and freeze-dried at -80°C for 40 hours to obtain a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold.

[0084] Example 4

[0085] This embodiment provides a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold, the preparation method of which includes the following steps:

[0086] (1) Weigh 1.44g PCL (molecular weight 80,000) and 0.96g gelatin (derived from pigskin) and dissolve them in 20mL of hexafluoroisopropanol (HFIP) to obtain a uniformly dispersed PCL / Gel spinning solution with a total mass concentration of 0.12g / mL; divide 20mL of PCL / Gel spinning solution into two 10mL syringes and perform electrospinning by spraying back and forth; set the electrospinning parameters as follows: spinning voltage 18kV, spinning distance 16cm, injection speed 1.5mL / h, needle type 24G, receiving roller speed 500rpm; dry the collected membrane under vacuum at 37℃ for 24h to obtain micro / nanofiber membrane;

[0087] (2) Weigh 2.5g of gelatin and dissolve it in 50mL of ultrapure water. Stir magnetically at 40℃ for 30min to fully dissolve the gelatin. Then cool at room temperature for 1h to obtain a gelatin sol with a mass concentration of 5%. Add sodium borohydride to the gelatin sol to make its concentration 0.5mol / L to obtain a foaming solution. Place the micro / nanofiber membrane in the foaming solution and foam for 10min. Then take it out and rinse it three times with deionized water to remove residual sodium borohydride to obtain a three-dimensional micro / nanofiber scaffold.

[0088] (3) Weigh 0.05g of hyaluronic acid and dissolve it in 10mL of ultrapure water. Stir magnetically at room temperature for 24h to obtain a hyaluronic acid sol with a mass concentration of 0.5%. Use a 22G syringe to draw 1mL of the hyaluronic acid sol and inject it into a 4cm³ volume. 3 The three-dimensional micro / nanofiber scaffold was filled with the scaffold and then frozen in a -20°C freezer for 16 hours. It was then transferred to a vacuum freeze dryer and freeze-dried at -80°C for 40 hours to obtain a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold.

[0089] Comparative Example 1

[0090] This comparative example provides a three-dimensional micro / nanofiber scaffold, the preparation method of which includes the following steps:

[0091] (1) The preparation of the micro / nanofiber membrane is described in step (1) of Example 1;

[0092] (2) Weigh 2.5g of gelatin and dissolve it in 50mL of ultrapure water. Stir magnetically at 40℃ for 30min to fully dissolve the gelatin. Then cool at room temperature for 1h to obtain a gelatin sol with a mass concentration of 5%. Add sodium borohydride to the gelatin sol to make its concentration 0.5mol / L to obtain a foaming solution. Place the micro / nanofiber membrane in the foaming solution and foam for 15min. Then take it out and rinse it three times with deionized water to remove residual sodium borohydride. Then freeze it in a refrigerator at -20℃ for 16h and then transfer it to a vacuum freeze dryer to freeze dry at -80℃ for 40h to obtain a three-dimensional micro / nanofiber scaffold.

[0093] Comparative Example 2

[0094] This comparative example provides a three-dimensional micro / nanofiber scaffold, the preparation method of which includes the following steps:

[0095] (1) The preparation of the micro / nanofiber membrane is described in step (1) of Example 1;

[0096] (2) Sodium borohydride was added to 50 mL of ultrapure water to make its concentration 0.5 mol / L to obtain a foaming solution; the micro-nanofiber membrane was placed in the foaming solution and foamed for 15 min, then taken out and rinsed three times with deionized water to remove residual sodium borohydride; then it was placed in a refrigerator at -20℃ for 16 h, and then transferred to a vacuum freeze dryer and freeze-dried at -80℃ for 40 h to obtain a three-dimensional micro-nanofiber scaffold.

[0097] The appearance images of the three-dimensional micro / nanofiber scaffolds prepared in Comparative Examples 1 and 2 are shown below. Figure 8 and Figure 9 As shown. Figure 8 It can be seen that the three-dimensional micro / nanofiber scaffolds prepared solely using sol as a foaming medium without injection filling exhibit slight collapse, but no delamination occurs. Figure 9It was found that the three-dimensional micro / nanofiber scaffolds prepared using sodium borohydride as the foaming liquid without injection filling exhibited severe collapse and obvious delamination. Both showed poor mechanical properties.

[0098] Scanning electron microscope (SEM) images of the upper surface of the three-dimensional micro / nanofiber scaffolds prepared in Comparative Examples 1 and 2 are shown below. Figure 10 and Figure 11 As shown. Figure 10 It can be seen that the sol, as a foaming medium, enhances the connection between fibers, initially forming a dense three-dimensional network structure; from Figure 11 It can be seen that the fiber packing is loose and the interaction between fibers is weak, resulting in poor mechanical properties.

[0099] The compressive stress-strain results of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffolds prepared in Examples 1-2 and the three-dimensional micro / nanofiber scaffolds prepared in Comparative Examples 1-2 are shown in the figure. Figure 12 As shown. Figure 12 It is known that the present invention utilizes a foaming liquid containing sol to foam and obtain a three-dimensional micro / nanofiber scaffold, providing preliminary mechanical support for the scaffold. Then, sol is filled and freeze-dried to obtain an integrated three-dimensional micro / nanofiber scaffold. Compared with the three-dimensional micro / nanofiber scaffolds obtained in Comparative Example 1, which only used sol as a foaming medium without injection filling, and Comparative Example 2, which used sodium borohydride as a single foaming liquid without injection filling, the mechanical compressive strength is significantly enhanced.

[0100] The compressive modulus results of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffolds prepared in Examples 1-2 and the three-dimensional micro / nanofiber scaffolds prepared in Comparative Examples 1-2 are shown in the figure. Figure 13 As shown. Figure 13 It can be seen that the integrated three-dimensional micro / nanofiber scaffold prepared by the method of the present invention has improved compression resistance and stability, making it suitable for applications under high load conditions.

[0101] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for fabricating a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold, characterized in that, Includes the following steps: A hydrophobic medical polymer material, a hydrophilic medical polymer material, and a solvent are mixed to obtain a spinning solution; the spinning solution is then electrospun to obtain a micro / nanofiber membrane. The micro-nanofiber membrane was foamed with a foaming liquid to obtain a three-dimensional micro-nanofiber scaffold. A three-dimensional micro / nanofiber scaffold was injected with sol-filled material B and then freeze-dried to obtain a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold. The foaming solution includes sol A and sodium borohydride; sol A includes one or more of gelatin sol, gelMA sol, and hyaluronic acid sol. The sol B includes one or more of gelatin sol, gelMA sol, silk fibroin sol, hyaluronic acid sol, and chitosan sol. The hydrophobic medical polymer material includes one or more of polycaprolactone, poly-L-lactic acid, poly-D-lactic acid, polylactic acid-glycolic acid copolymer, and poly-L-lactide-caprolactone; the hydrophilic medical polymer material includes one or more of collagen, gelatin, silk fibroin, chitosan, hyaluronic acid, polyvinyl alcohol, polyethylene glycol, and polyethylene oxide.

2. The method for preparing a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold according to claim 1, characterized in that, The electrospinning parameters are as follows: spinning voltage is 17~20 kV; spinning distance is 12~16 cm; injection speed is 1~1.5 mL / h; needle type is 21~24 G; receiving roller speed is 100~500 rpm.

3. The method for preparing a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold according to claim 1, characterized in that, The mass concentration of sol A is 0.01~5%; the concentration of sodium borohydride in the foaming solution is 0.1~1 mol / L.

4. A method for preparing a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold according to claim 1 or 3, characterized in that, The foaming time is 10~60 min.

5. The method for preparing a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold according to claim 4, characterized in that, The mass concentration of sol B is 0.1-20%.

6. The method for preparing a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold according to claim 5, characterized in that, The injection filling method is as follows: sol B is drawn using a syringe and injected into the three-dimensional micro / nanofiber scaffold; the volume ratio of sol B to the volume of the three-dimensional micro / nanofiber scaffold is 1~5 mL:1~4 cm³. 3 .

7. The method for preparing a mechanically reinforced integrated three-dimensional micro / nanofiber scaffold according to claim 6, characterized in that, The freeze-drying includes freezing and freeze-drying; the freezing temperature is -20℃; the freezing time is 12~16 h; the freeze-drying temperature is -50~-80℃; the freeze-drying time is 24~48 h.

8. A mechanically reinforced integrated three-dimensional micro / nanofiber scaffold prepared by the method of any one of claims 1 to 7.

9. The application of the mechanically reinforced integrated three-dimensional micro / nanofiber scaffold of claim 8 in the preparation of biomedical materials.

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