A double-layer composite patch with healing and repairing function and its preparation method

Abstract

The present invention belongs to the technical field of patch materials and relates to a double-layer composite patch with a healing and repairing function and a preparation method thereof. The double-layer composite patch is composed of an oriented fiber layer and a random dense layer composited up and down; the components of the oriented fiber layer are synthetic polymers and natural polymers, the synthetic polymer is polylactic acid, poly (L-lactide-caprolactone) or poly (lactic acid-glycolic acid copolymer), and the natural polymer is insoluble type I collagen; during preparation, the oriented fiber membrane obtained by electrospinning is first cut and pre-tensioned and placed in a bidirectional clamping device, and then the bidirectional clamping device is placed in a vacuum oven for annealing treatment, and finally the random dense membrane obtained by electrospinning and the oriented fiber membrane after annealing treatment are composited by ultrasonic welding to obtain the double-layer composite patch. The double-layer composite patch of the present invention has both anti-inflammatory and repair functions while achieving the synergy of "exogenous efficient barrier" and "endogenous precise guidance" functions; the preparation method is simple.

Description

Technical Field

[0001] The invention belongs to the technical field of patch materials and relates to a double-layer composite patch with a healing and repairing function and a preparation method thereof. Background Art

[0002] Tendon injury repair is a difficult problem in clinical orthopedics and sports medicine, with a repair failure rate as high as 10% to 30%. The main reasons are insufficient biocompatibility of patch materials and inflammatory response interfering with the repair process.

[0003] Temporary rotator cuff patches are designed to enhance intraoperative rotator cuff sutures and provide a scaffold for the adhesion of new tissue and blood vessels. These patches create a stress-distributing structure at the suture interface of the rotator cuff stump, effectively reducing tension in the suture area. This reduces the mechanical stress and subsequent inflammatory response caused by the postoperative resistance of the affected limb to gravity. This provides mechanical support for the injured rotator cuff, reduces postoperative immobilization time, and facilitates early functional rehabilitation. By sharing the shoulder abduction load, they provide immediate mechanical support to the repaired rotator cuff, thereby delaying disuse atrophy of the rotator cuff muscles and reducing scar tissue fatty infiltration and tendon degeneration in the repaired area. The biocompatibility of a tendon patch is a key factor influencing the effectiveness of tendon repair. Its core role lies in its interaction with human tissue, directly impacting post-repair tissue healing, functional recovery, and the risk of complications. An inflammatory microenvironment can lead to scar tissue proliferation, reducing the mechanical properties of the repaired tissue. Furthermore, the intrusion of exogenous pathogens or foreign bodies can trigger secondary infection, exacerbating the inflammatory response and further hindering repair.

[0004] Existing patch materials have many technical bottlenecks: (1) Due to the disordered fiber orientation, the tensile strength of non-directional patches along the long axis of the tendon is lower than that of natural tendons, which makes the patch tearing or interface separation easy when the repair interface is subjected to axial stress. In addition, the disordered structure patch induces abnormal proliferation of fibroblasts, forming scar tissue mainly composed of type III collagen (healthy tissue is mainly composed of type I collagen), which cannot form effective mechanical support; (2) Although the patch made of soluble collagen has good biocompatibility, it has poor mechanical properties and a short degradation time, which may lead to insufficient structural stability of the patch during long-term repair and make it difficult to meet the needs of long-term rotator cuff repair; (3) Some patches use synthetic polymer materials and are prepared into fiber membranes through processes such as electrospinning. These patches have good mechanical strength and certain degradation properties, and can provide temporary mechanical support for tendon repair. However, synthetic polymer materials have poor hydrophilicity and are easy to adsorb inflammatory cells and proteins, triggering exogenous inflammatory reactions. In addition, their limited biocompatibility is not conducive to the recruitment and growth of endogenous repair cells.

[0005] For example, patent CN117122740A discloses a rotator cuff tear patch and its preparation method, which includes an ordered fiber membrane layer and a disordered fiber membrane layer. The introduction of a variable speed region fiber membrane layer between the ordered and disordered fiber membrane layers reduces the difference in fiber orientation structure, strengthens the bonding between the layers, and reduces the occurrence of stratification. However, controlling fiber orientation through variable speed spinning relies on changes in the drum speed to form an ordered structure, which has limited long-term stability. Furthermore, the inflammatory microenvironment during rotator cuff repair is not regulated, resulting in limited repair effects on the rotator cuff.

[0006] Patent CN102525876B discloses a gambogic acid-polyethylene glycol-polylactic acid block copolymer nanoparticle formulation, its preparation method, and application. By loading gambogic acid into a polyethylene glycol-polylactic acid block copolymer (mPEG-PLA), the nanoparticle relies on drug release to modulate the inflammatory microenvironment and promote repair. However, this approach requires consideration of the drug's encapsulation efficiency and release rate, as well as potential risks associated with long-term use, such as drug residues and toxic reactions.

[0007] Therefore, it is of great significance to study a double-layer composite patch with a healing and repairing function and a preparation method thereof to solve the problems existing in the prior art. Summary of the Invention

[0008] The purpose of the present invention is to solve the problems existing in the prior art and to provide a double-layer composite patch with a healing and repairing function and a preparation method thereof.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A double-layer composite patch with a healing and repairing function, composed of an oriented fiber layer and a random dense layer;

[0011] The components of the oriented fiber layer are synthetic polymers and natural polymers, the synthetic polymer is polylactic acid (PLA), poly L-lactide-caprolactone (PLCL) or polylactic acid-co-glycolic acid (PLGA), and the natural polymer is insoluble type I collagen;

[0012] PLCL is synthesized by copolymerization of L-lactide and ε-caprolactone, while PLGA is polymerized by lactic acid and glycolic acid. Both contain PLA structural units. Both the oriented fiber layer and the random dense layer structure contain PLA structural units and are chemically homologous. PLA segments serve as the molecular bridge for stable composites (e.g., ultrasonic welding) between the random dense layer and the oriented fiber layer.

[0013] The components of the random dense layer are polyethylene glycol-polylactic acid block copolymer (s-PLLA-PEG) with a star-shaped structure;

[0014] In the star-shaped polyethylene glycol-polylactic acid block copolymer, the polyethylene glycol segment accounts for 15-40 mol%;

[0015] The oriented fiber layer and the random dense layer are composited by ultrasonic welding.

[0016] The materials used for the oriented fiber layer of the present invention include synthetic polymers and natural polymers, which combine the mechanical properties of synthetic materials with the biocompatibility advantages of natural materials; and after the oriented fiber layer undergoes an unconventional annealing treatment, the mechanical properties are more stable. The random dense layer uses a diblock copolymer of polylactic acid and polyethylene glycol. Its hydrophilic surface can directly reduce inflammatory cells and protein adsorption without the need for additional loading of drugs or bioactive ingredients, simplifying the preparation process while avoiding the problem of controlling sudden or sustained drug release, making it suitable for long-term implantation scenarios. The oriented fiber layer and the random dense layer work together to achieve "endogenous regeneration guidance" and "exogenous inflammation barrier" at the same time.

[0017] As the preferred technical solution:

[0018] In the double-layer composite patch with the function of promoting healing and repair as described above, the polyethylene glycol-polylactic acid block copolymer with a star structure is a three-arm star polyethylene glycol-polylactic acid block copolymer, a four-arm star polyethylene glycol-polylactic acid block copolymer or an eight-arm star polyethylene glycol-polylactic acid block copolymer.

[0019] The double-layer composite patch with the function of promoting healing and repairing as described above has a weight average molecular weight of 5×10 4 ~15×10 4 Da, the weight average molecular weight of natural polymer is 5×10 4 ~10×10 4 Da.

[0020] The double-layer composite patch with the function of promoting healing and repairing as described above has a weight average molecular weight of 5×10 4 ~20×10 4 Da.

[0021] In the double-layer composite patch with the function of promoting healing and repair as described above, the mass ratio of the synthetic polymer to the natural polymer in the oriented fiber layer is 4:6 to 8:2.

[0022] In the double-layer composite patch with the function of promoting healing and repair as described above, the thickness of the oriented fiber layer is 0.1-0.5 mm, and the thickness of the random dense layer is 0.05-0.2 mm.

[0023] The present invention also provides a method for preparing a double-layer composite patch with a healing and repairing function as described in any one of the above items, comprising the following steps:

[0024] (1) The oriented fiber membrane obtained by electrospinning is cut and pre-tensioned and placed in a bidirectional clamping device, clamped in both the X-axis and Y-axis directions, and then the bidirectional clamping device is placed in a vacuum oven for annealing;

[0025] (2) The random dense membrane obtained by electrospinning and the oriented fiber membrane after annealing were composited by ultrasonic welding to produce a double-layer composite patch with healing and repair functions.

[0026] As the preferred technical solution:

[0027] In the method for preparing a double-layer composite patch with a healing and repairing function as described above, the electrospinning process parameters for the oriented fiber layer include: a voltage of 10-25 kV, a spinning speed of 0.8-2 mL / h, a receiving distance of 10-20 cm, a spinning time of 2-5 hours, a needle diameter of 20-22 Gauges, and a drum speed of 2000-3000 rpm;

[0028] The electrospinning process parameters for the random dense layer include: voltage of 10-20 kV, spinning speed of 0.1-1 mL / h, receiving distance of 10-20 cm, spinning time of 2-5 h, needle diameter of 20-22 G, and drum speed of 100-500 rpm;

[0029] The spinning solution concentrations during electrospinning of the random dense layer and the oriented fiber layer were both in the range of 6~12wt%.

[0030] In the method for preparing a double-layer composite patch with a healing and repairing function as described above, the annealing temperature in step (1) is 60-80°C, the heating rate during annealing is 3-5°C / min, and the annealing time is 2-24h. After the annealing is completed, the electrospun membrane is naturally cooled to room temperature in a vacuum oven.

[0031] The oriented fiber layer must be annealed. The annealing temperature of the present invention is set to ensure that the annealing temperature is above the glass transition temperature (Tg) of the material used in the oriented fiber layer. The Tg range of PLA is 55-60°C; the Tg range of PLCL is typically between -20°C and 50°C, with the specific value determined by the ratio of L-lactide (LLA) to ε-caprolactone (CL); and the Tg range of PLGA is 40-60°C, primarily influenced by the ratio of lactic acid (LA) to glycolic acid (GA).

[0032] In the method for preparing a double-layer composite patch with a healing and repairing function as described above, the power of ultrasonic welding in step (2) is 100-300 W, the time is 1-3 s, and the pressure is 0.1-0.5 MPa.

[0033] Principle of the invention:

[0034] The present invention provides a double-layer composite patch with a healing and repair function. In terms of the repair function, the hydrophilicity and anti-protein adsorption properties of the upper random dense layer can provide a stable microenvironment for the repair process, reduce the interference of inflammatory cells and foreign matter on the repair area, and thus indirectly support the repair function of the oriented fiber layer; the orientation structure of the lower oriented fiber layer is stable, thereby enhancing the mechanical properties and biocompatibility of the patch, and can serve as a support layer for the random dense layer, and has the function of promoting the recruitment and directional growth of mesenchymal stem cells. The stable orientation structure can guide the migration and differentiation of stem cells along the fiber direction, accelerating the endogenous repair process.

[0035] The PEG segments in the random dense layer provide a stable microenvironment for the repair process, reducing interference from inflammatory cells and foreign matter in the repair area. The insoluble type I collagen in the oriented fibrous layer promotes cell adhesion, proliferation, and migration. The two complement each other in their healing-promoting functions: the star-shaped polyethylene glycol-polylactic acid block copolymer blocks inflammatory cells, reducing interference with the repair process, while the insoluble type I collagen better guides endogenous repair within the stable microenvironment it creates. Ultimately, this achieves the effective synergy of "exogenous efficient barrier" and "endogenous precise guidance."

[0036] In the prior art, polyethylene glycol-polylactic acid block copolymers are commonly used for drug loading, with a high proportion of PLA segments, and the focus is on regulating the degradation properties of the block copolymer. However, the present invention primarily relies on the hydrophilic segments of the star-shaped polyethylene glycol-polylactic acid block copolymer to isolate external inflammatory cell interference, ensure a stable repair microenvironment, and assist in the repair of the alignment layer. The main focus is on the proportion of PEG segments, and the proportion of PEG segments in the polymer used is much higher than that of the polyethylene glycol-polylactic acid block copolymers used for drug loading in the prior art.

[0037] The PLA segments in the random dense layer provide the necessary film-forming properties, mechanical support, and chemical compatibility with the underlying oriented layer material (PLA, PLCL, or PLGA). The long PLA chains ensure material stability and controllable degradation. Furthermore, both the oriented fiber layer and the random dense layer contain PLA structural units, demonstrating chemical homology. The PLA segments serve as the molecular bridge for stable composite bonding between the random dense layer and the oriented fiber layer (e.g., ultrasonic welding).

[0038] Prior to lamination, the present invention employs an annealing process for the oriented fiber layer. During the annealing process, the fiber membrane is pre-tensioned and placed in a bidirectional clamping device, which allows the fiber membrane to relax. During the annealing process, the fiber membrane shrinks due to temperature. The bidirectional clamping device eliminates internal stress during this shrinkage process, improving the material's thermal stability and creep resistance. This can reduce deformation caused by body temperature or mechanical loads after long-term implantation in the body, ensuring that the oriented fiber layer maintains its topographical guidance for cell adhesion and migration. This also extends the patch's lifespan and reduces the risk of secondary surgery.

[0039] Compared with the ordinary annealing process, the annealing process of the present invention is to perform stretching and annealing simultaneously, and can utilize the shrinkage effect to achieve the purpose of eliminating internal stress. The ordinary annealing process is to stretch first and then anneal. The membrane material may have local deformation or structural imbalance due to being subjected to force in only one direction, which may lead to large performance differences in the material due to different force directions in actual applications.

[0040] The annealed oriented fiber membrane was then composited with the random dense membrane via ultrasonic welding. The glass transition temperature of the PEG segments is -60°C, while that of the PLA segments is between 55°C and 60°C. The localized high temperatures of ultrasonic welding cause the PEG segments to flow. Based on the principle of surface energy minimization, the PEG segments migrate to high-energy interfaces, where they accumulate and form a hydration barrier, effectively isolating them from external inflammatory cell interference.

[0041] Beneficial effects:

[0042] (1) The double-layer composite patch of the present invention has a healing and repairing function. The oriented fiber layer after annealing treatment not only has high strength and toughness, and can withstand the tension and pressure during shoulder joint movement, but also can maintain a stable orientation structure, provide guidance for the directional growth of cells, promote the orderly regeneration of rotator cuff tissue, and improve the repair effect; at the same time, this stable oriented fiber layer can provide guidance for the directional migration and growth of mesenchymal stem cells, and promote endogenous repair;

[0043] (2) The double-layer composite patch of the present invention, which has the function of promoting healing and repair, uses insoluble type I collagen, which has a stable three-dimensional structure that makes it less susceptible to degradation and absorption in the body compared to commonly used soluble collagen, and can maintain the integrity and functionality of the patch for a long time. In addition, insoluble type I collagen can also provide good attachment sites for cells, promote cell adhesion, proliferation and differentiation, facilitate the regeneration and repair of rotator cuff tissue, and improve the fusion effect between the patch and surrounding tissues;

[0044] (3) The double-layer composite patch of the present invention has the function of promoting healing and repair. Based on the hydrophilic characteristics of polylactic acid-glycolic acid copolymer and combined with the hydrophilic anti-fouling theory, polylactic acid-glycolic acid copolymer has good hydrophilicity. With the help of ultrasonic welding technology, a hydration layer can be formed on the surface of the patch to reduce the adsorption of exogenous inflammatory cells and proteins, thereby hindering the interference of exogenous inflammation. Through the hydrophilic anti-fouling design, the infiltration of inflammatory cells can be significantly reduced, creating a good microenvironment for tendon repair and assisting the repair effect of the oriented fiber layer.

[0045] (4) The present invention provides a double-layer composite patch with a healing and repairing function. The upper random dense layer has the function of hindering exogenous inflammatory interference. Its hydrophilic and anti-fouling design can reduce the adsorption and infiltration of inflammatory cells, creating a good environment for the repair of the lower layer, and playing an auxiliary role in promoting healing and repair. At the same time, the oriented fiber layer of the lower layer has the function of promoting the recruitment and directional growth of mesenchymal stem cells. The stable oriented structure can guide the migration and differentiation of stem cells along the fiber direction, accelerating the endogenous repair process. This double-layer structure design is mainly based on the repair function of the oriented fiber layer, supplemented by the microenvironmental regulation of the random dense layer, forming a superimposed healing and repairing effect, overcoming the limitations of single-structure patches.

[0046] (5) The present invention provides a method for preparing a double-layer composite patch with a healing and repairing function. The random dense layer prepared by electrospinning uses a diblock copolymer of polylactic acid and polyethylene glycol (i.e., a polylactic acid-glycolic acid copolymer with a star-shaped structure), which can reduce the adsorption of exogenous inflammatory cells and proteins, provide a stable microenvironment for the repair process, reduce the interference of inflammatory cells and foreign matter on the repair area, and thus indirectly support the repair function of the oriented fiber layer; the oriented fiber layer prepared by electrospinning and annealing process uses insoluble type I collagen. This material has excellent biocompatibility and stability, can provide a stable orientation structure, promote tendon regeneration, and avoid the problems of excessive degradation or insufficient mechanical properties that may be caused by soluble collagen. At the same time, through annealing treatment, the orientation structure of the oriented fiber layer is ensured to be stable, thereby enhancing the mechanical properties and biocompatibility of the patch, and promoting the recruitment and directional growth of mesenchymal stem cells. The stable orientation structure can guide the stem cells to migrate and differentiate along the fiber direction, accelerating the endogenous repair process. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of a bidirectional clamping device;

[0048] Figure 2 Schematic diagram of the collagen fiber structure in the patch repair tissue of Example 1.

[0049] Among them, 1-fixed frame; 2-upper splint; 3-pulley; 4-sensor; 5-spring telescopic rod; 6-lower splint; 7-base. DETAILED DESCRIPTION

[0050] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0051] The schematic diagram of the bidirectional clamping device used for annealing in the present invention is as follows Figure 1 As shown:

[0052] 1. Overall frame structure;

[0053] The bidirectional clamping device is a rectangular frame structure made of high-temperature resistant metal materials (such as 316L stainless steel or titanium alloy), ensuring stable operation at an annealing temperature of 60~80℃ and in a vacuum environment.

[0054] External frame (i.e. fixed frame 1) size: 80mm × 80mm (length × width), with space reserved for clamping operation;

[0055] The internal clamping area measures 50mm x 60mm, accommodating the cut oriented fiber membrane (typically 50mm x 60mm). The frame utilizes an integrated welding process, with a 2.5mm thick frame around each edge, ensuring uniform force during clamping and preventing deformation due to tension.

[0056] The base 7, the supporting structure for the entire device, is constructed from 6mm-thick 316L stainless steel or titanium alloy plates, matching the dimensions of the external frame. Bolted to the external frame, it forms a rigid support system capable of withstanding the loads generated by the tension of the fiber membrane and the weight of the frame during annealing. Its high-temperature resistance ensures it remains stable in a vacuum environment at temperatures between 60°C and 80°C, providing a stable foundation for the entire clamping device.

[0057] 2. Bidirectional clamping mechanism;

[0058] The clamping mechanism consists of an upper clamping plate 2 and a lower clamping plate 6. The upper and lower clamping plates are "L-shaped" structures and are stainless steel plates with a thickness of 1.5 mm. The inner contact surface is provided with fine teeth or silicone anti-slip pads to prevent the fiber membrane from sliding; the spring is a stainless steel compression spring, one end of which is fixed to the frame and the other end is connected to the clamping plate to provide elastic clamping force; the movable clamp is connected to the frame through a guide rail and can slide along the X / Y axis direction to adjust the distance between the clamping plate and the frame.

[0059] 3. Tension adjustment system;

[0060] Pulley 3 is a key component of the tension adjustment system of the bidirectional clamping device. Made of 316L stainless steel, it has a diameter of 3mm and a thickness of 1mm, and its surface is polished to reduce friction. It is mounted at the ends of the upper and lower clamping plates 2 and 6, working in conjunction with the spring-loaded telescopic rod 5. It is connected to the frame via bearings for flexible rotation. During tension adjustment, the rotation of pulley 3 converts the sliding friction generated by the movement of the clamping plates into rolling friction, preventing local damage or fiber breakage of the fiber membrane due to frictional forces during the tension adjustment process and ensuring that the pre-tension is evenly distributed across the entire surface of the fiber membrane.

[0061] Pretensioning mechanism: A spring-type telescopic rod 5 is attached to the movable clamps on the X and Y axes, respectively. One end of the spring is fixed to the frame, and the other end is connected to the clamp. When the clamps are moved outward, the spring is stretched, applying a uniform pretension to the fiber membrane (with a tension range of 0.5 to 3N). During the experiment, the fabric was fixed to the upper and lower clamps on both sides, and the tension of the fabric was varied by adjusting the pressure of the adjustment bolts on the sensor 4.

[0062] 4. Materials and compatibility;

[0063] The main frame and clamping parts are made of 316L stainless steel or titanium alloy, which has the characteristics of high temperature resistance (≥80℃) and corrosion resistance (adaptable to vacuum environment).

[0064] The non-slip texture material of the clamping surface is made of high temperature resistant silicone to avoid aging or adhesion of the fiber membrane under high temperature.

[0065] The test methods involved in the performance indicators of the present invention are as follows:

[0066] (1) Macrophage polarization experiment: The patch was cut into 1 cm² size and immersed in DMEM medium containing 10% fetal bovine serum at a ratio of 1 g / mL. After extraction at 37°C for 72 hours, the supernatant was filtered and used as the patch extract. Cell ratio: Mouse macrophage Raw 264.7 cells were co-incubated with the extract at a volume ratio of 1:10, and the cell suspension concentration was 5×10 5 cells / mL (i.e., each mL of culture medium contains 5×10 5 The proportions of M1 (pro-inflammatory) and M2 (anti-inflammatory) macrophages were measured by flow cytometry using macrophage and patch extracts. Compared with the blank control group, the proportion of M1 macrophages decreased by 30%-50% and the proportion of M2 macrophages increased by 20%-40% after patch treatment, indicating that the patch has a good anti-inflammatory effect.

[0067] (2) Inflammatory factor detection: Enzyme-linked immunosorbent assay (ELISA) and other methods were used to detect the effect of the patch extract on the secretion of inflammatory factors (such as TNF-α, IL-6, IL-1β, etc.). Macrophages stimulated with 1 μg / mL lipopolysaccharide (LPS) served as the positive inflammation control group. Compared with the inflammation control group, the secretion of inflammatory factors such as TNF-α, IL-6, and IL-1β decreased by 50% to 72%, indicating that the patch can effectively inhibit the inflammatory response.

[0068] (3) Biomechanical testing: The maximum tensile force and elastic modulus of the repaired tissue were measured according to ASTM D3039. The data range is: 8 to 12 weeks after surgery, the maximum tensile force of the patch implantation group recovered to 70% to 90% of the normal tissue, and the elastic modulus recovered to 60% to 80% of the normal tissue, indicating that the patch helps to restore the mechanical properties of the tissue.

[0069] (4) Cell migration assay: The scratch test was used to examine the role of the patch in guiding the migration of mesenchymal stem cells. Compared with the blank control group, the cell migration distance in the patch group increased by 58% to 125%, indicating that the patch can effectively guide the migration of stem cells to the damaged area and promote repair.

[0070] (5) Histological evaluation: Masson trichrome staining was used to evaluate the histological changes after patch repair.

[0071] (6) Repair the maturity of the organization:

[0072] Cell density (Cells / mm²): Normal tendon: 200-400 cells / mm²; blank control group (injury without treatment): 1200±150 cells / mm²; patch group: 350±60 cells / mm²;

[0073] Collagen continuity (%): Normal tendon >90% continuous fibers; blank control group: 45±5% continuous fibers; patch group: 85±9% continuous fibers. This indicates that the maturity of the repair tissue (cell density and collagen fiber continuity) is significantly higher than that of the blank control group.

[0074] The sources of some of the substances of the present invention are as follows:

[0075] Type I collagen extracted from bovine Achilles tendon: Beijing Bangsai Technology Co., Ltd., purity 95-99.9%.

[0076] Three-arm star-shaped polyethylene glycol-polylactic acid block copolymer: Synthesized according to the reference (Degradation characteristics of multi-arm star-shaped polyethylene glycol-polylactic acid block copolymer [J]. Polymer Materials Science and Engineering, 2013, 29(11): 67-70+75.).

[0077] Four-arm star-shaped polyethylene glycol-polylactic acid copolymer: Xi'an Ruixi Biotechnology Co., Ltd., R-PEG-5048.

[0078] Eight-armed star-shaped polyethylene glycol-polylactic acid copolymer: synthesized according to the reference (Stereocomplexed 8-armed poly(ethylene glycol)epoly(lactide) star block copolymer hydrogels: Gelationmechanism, mechanical properties and degradation behavior [ J ]. Polymer, 2012, 53(14): 2809-2817.).

[0079] Example 1

[0080] A method for preparing a double-layer composite patch with a healing and repairing function comprises the following steps:

[0081] (1) The weight average molecular weight is 5×10 4 Da of polylactic acid and a weight average molecular weight of 9×10 4 The oriented fiber membrane was obtained by electrospinning type I collagen extracted from bovine Achilles tendon of Da; the mass ratio of polylactic acid to collagen in the oriented fiber membrane was 6:4;

[0082] The electrospinning process parameters include: voltage of 10 kV, spinning speed of 0.8 mL / h, receiving distance of 10 cm, spinning time of 5 h, needle diameter of 20 G, drum speed of 2000 rpm; spinning solution concentration of 6 wt % and solvent of chloroform;

[0083] (2) The oriented fiber membrane obtained by electrospinning was cut into 50 mm × 60 mm pieces and pre-tensioned and placed in a bidirectional clamping device, and then the bidirectional clamping device was placed in a vacuum oven at 60 ° C for annealing;

[0084] The pre-tension is 0.5N; the heating rate during annealing is 3°C / min, and the annealing time is 24h;

[0085] (3) A four-arm star-shaped polyethylene glycol-polylactic acid block copolymer was electrospun to obtain a random dense membrane; in the four-arm star-shaped polyethylene glycol-polylactic acid block copolymer, the proportion of polyethylene glycol segments was 25 mol%;

[0086] The electrospinning process parameters included: voltage of 10 kV, spinning speed of 0.1 mL / h, receiving distance of 10 cm, spinning time of 5 h, needle diameter of 20 G, drum speed of 100 rpm; spinning solution concentration of 6 wt % and solvent of chloroform;

[0087] (4) The random dense membrane obtained by electrospinning and the oriented fiber membrane after annealing are composited by ultrasonic welding to produce a double-layer composite patch with healing and repair functions;

[0088] Among them, the power of ultrasonic welding is 100W, the time is 3s, and the pressure is 0.1MPa.

[0089] The final double-layer composite patch with healing and repair function was composed of an oriented fiber layer and a random dense layer. In the macrophage polarization experiment, compared with the blank control group, the proportion of M1 macrophages decreased by 35% and the proportion of M2 macrophages increased by 25% after patch treatment. In the inflammatory factor detection experiment, compared with the inflammatory control group, the secretion of TNF-α, IL-6, and IL-1β inflammatory factors decreased by 55%, 58%, and 60%, respectively. Eight weeks after surgery, the maximum tensile force of the patch implantation group recovered to 70% of that of normal tissue, and the elastic modulus recovered to 60% of that of normal tissue. In the cell migration experiment, the number of migrating cells in the patch group was 135±12, which was a 125% increase compared with the blank control group. The cell density of the patch group was 340±30 cells / mm², and the continuous fiber was 82±5%.

[0090] like Figure 2 As shown in the figure, the Sirius red staining method was used to color the collagen fibers in the patch repair tissue (Sirius red is a strong acid dye that can combine with the basic groups in the collagen molecules and specifically bind to collagen through van der Waals forces, thereby). Under a fluorescence microscope, it was found that the arrangement order of the collagen fibers in the patch repair tissue was significantly higher than that in the blank control group, showing a "corrugated" structure that is closer to natural tendon tissue.

[0091] Comparative Example 1

[0092] A method for preparing a double-layer composite patch is basically the same as that in Example 1, except that the four-arm star-shaped polyethylene glycol-polylactic acid copolymer in step (3) is replaced by linear mPEG-PLA (Jinan Daigang Bioengineering Co., Ltd., DG-MPEG).

[0093] The final double-layer composite patch was composed of an oriented fiber layer and a random dense layer. In the macrophage polarization experiment, compared with the blank control group, the proportion of M1 macrophages decreased by 18% and the proportion of M2 macrophages increased by 12% after patch treatment. In the inflammatory factor detection experiment, compared with the inflammatory control group, the secretion of TNF-α, IL-6, and IL-1β inflammatory factors decreased by 35%, 30%, and 32%, respectively. Eight weeks after surgery, the maximum tensile force of the patch implantation group recovered to 60% of that of normal tissue, and the elastic modulus recovered to 50% of that of normal tissue. In the cell migration experiment, the number of migrating cells in the patch group was 87±10, which was a 45% increase compared with the blank control group. The cell density of the patch group was 600±70 cells / mm², and the continuous fiber was 60±6%.

[0094] Comparing Comparative Example 1 with Example 1, it can be found that the anti-inflammatory and mechanical properties of the double-layer composite patch in Comparative Example 1 are significantly lower than those in Example 1. This is because the linear structure PEG coverage is low and a dense hydrophilic layer cannot be formed; and the molecular chains are disordered, which reduces the interfacial bonding strength.

[0095] Comparative Example 2

[0096] A method for preparing a double-layer composite patch is basically the same as that in Example 1, except that the polyethylene glycol segment in the four-arm star-shaped polyethylene glycol-polylactic acid copolymer in step (3) accounts for 10 mol%.

[0097] The final double-layer composite patch was composed of an oriented fiber layer and a random dense layer. In the macrophage polarization experiment, compared with the blank control group, the proportion of M1 macrophages decreased by 20% and the proportion of M2 macrophages increased by 15% after patch treatment. In the inflammatory factor detection experiment, compared with the inflammatory control group, the secretion of TNF-α, IL-6, and IL-1β inflammatory factors decreased by 40%, 35%, and 38%, respectively. Eight weeks after surgery, the maximum tensile force of the patch implantation group recovered to 60% of that of normal tissue, and the elastic modulus recovered to 50% of that of normal tissue. In the cell migration experiment, the number of migrating cells in the patch group was 90±8, which was 50% higher than that in the blank control group. The cell density of the patch group was 500±60 cells / mm², and the continuous fiber was 65±7%.

[0098] Comparing Comparative Example 2 with Example 1, it can be found that the anti-inflammatory effect of the double-layer composite patch in Comparative Example 2 is significantly lower than that in Example 1. This is because the PEG content is too low to effectively block inflammatory cells and interfere with the repair and guidance function of collagen.

[0099] Comparative Example 3

[0100] A method for preparing a double-layer composite patch is basically the same as that in Example 1, except that the polyethylene glycol segment in the four-arm star-shaped polyethylene glycol-polylactic acid copolymer in step (3) accounts for 45 mol%.

[0101] The final double-layer composite patch was composed of an oriented fiber layer and a random dense layer. In the macrophage polarization experiment, compared with the blank control group, the proportion of M1 macrophages decreased by 25% and the proportion of M2 macrophages increased by 10% after patch treatment. In the inflammatory factor detection experiment, compared with the inflammatory control group, the secretion of TNF-α, IL-6, and IL-1β inflammatory factors decreased by 30%, 25%, and 28%, respectively. Eight weeks after surgery, the maximum tensile force of the patch implantation group recovered to 50% of that of normal tissue, and the elastic modulus recovered to 40% of that of normal tissue. In the cell migration experiment, the number of migrating cells in the patch group was 78±9, which was a 30% increase compared with the blank control group. The cell density of the patch group was 450±55 cells / mm², and the continuous fiber was 55±5%.

[0102] Comparing Comparative Example 3 with Example 1, it can be found that the repair performance and mechanical properties of the double-layer composite patch in Comparative Example 3 are significantly lower than those in Example 1. This is because the excessively high proportion of PEG weakens the mechanical properties of PLA and causes structural collapse of the patch; and the formed hydrophilic layer is too thick, hindering cell-collagen interaction and inhibiting endogenous repair.

[0103] Example 2

[0104] A method for preparing a double-layer composite patch with a healing and repairing function comprises the following steps:

[0105] (1) The weight average molecular weight is 15×10 4 Da of polylactic acid and a weight average molecular weight of 5×10 4 Type I collagen extracted from bovine Achilles tendon was electrospun to obtain an oriented fiber membrane; the mass ratio of polylactic acid to collagen in the oriented fiber membrane was 7:3;

[0106] The electrospinning process parameters include: voltage of 15 kV, spinning speed of 1 mL / h, receiving distance of 12 cm, spinning time of 4 h, needle diameter of 21 G, drum speed of 2200 rpm; spinning solution concentration of 8 wt% and solvent of hexafluoroisopropanol;

[0107] (2) The oriented fiber membrane obtained by electrospinning was cut into 50 mm × 60 mm pieces and pre-tensioned and placed in a bidirectional clamping device, and then the bidirectional clamping device was placed in a vacuum oven at 65 ° C for annealing;

[0108] Among them, the pre-tension is 1N; the heating rate during annealing is 4℃ / min, and the annealing time is 20h;

[0109] (3) An eight-arm star-shaped polyethylene glycol-polylactic acid block copolymer was electrospun to obtain a random dense membrane; in the eight-arm star-shaped polyethylene glycol-polylactic acid block copolymer, the polyethylene glycol segment accounts for 40 mol%;

[0110] The electrospinning process parameters include: voltage of 15 kV, spinning speed of 0.5 mL / h, receiving distance of 15 cm, spinning time of 3 h, needle diameter of 21 G, drum speed of 200 rpm; spinning solution concentration of 8 wt% and solvent of hexafluoroisopropanol;

[0111] (4) The random dense membrane obtained by electrospinning and the oriented fiber membrane after annealing are composited by ultrasonic welding to produce a double-layer composite patch with healing and repair functions;

[0112] Among them, the power of ultrasonic welding is 150W, the time is 2.5s, and the pressure is 0.2MPa.

[0113] The final double-layer composite patch with healing and repair function was composed of an oriented fiber layer and a random dense layer. In the macrophage polarization experiment, compared with the blank control group, the proportion of M1 macrophages decreased by 50% and the proportion of M2 macrophages increased by 40% after patch treatment. In the inflammatory factor detection experiment, compared with the inflammatory control group, the secretion of TNF-α, IL-6, and IL-1β inflammatory factors decreased by 70%, 68%, and 72%, respectively. Twelve weeks after surgery, the maximum tensile force of the patch implantation group recovered to 90% of that of normal tissue, and the elastic modulus recovered to 80% of that of normal tissue. In the cell migration experiment, the number of migrating cells in the patch group was 95±8, which was 58.30% higher than that in the blank control group. The cell density of the patch group was 360±40 cells / mm², and the continuous fiber ratio was 87±6%.

[0114] Example 3

[0115] A method for preparing a double-layer composite patch with a healing and repairing function comprises the following steps:

[0116] (1) The weight average molecular weight is 7×10 4 Da polylactic acid-glycolic acid copolymer and a weight average molecular weight of 7×10 4 Type I collagen extracted from bovine Achilles tendon was electrospun to obtain an oriented fiber membrane; the mass ratio of poly(lactic-co-glycolic acid) copolymer to collagen in the oriented fiber membrane was 8:2;

[0117] The electrospinning process parameters include: voltage of 20 kV, spinning speed of 1.2 mL / h, receiving distance of 14 cm, spinning time of 3 h, needle diameter of 22 G, drum speed of 2400 rpm; spinning solution concentration of 12 wt%; solvent of N,N-dimethylformamide;

[0118] (2) The oriented fiber membrane obtained by electrospinning was cut into 50 mm × 60 mm pieces and pre-tensioned and placed in a bidirectional clamping device, and then the bidirectional clamping device was placed in a vacuum oven at 70 ° C for annealing;

[0119] Among them, the pre-tension is 1.5N; the heating rate during annealing is 5℃ / min, and the annealing time is 14h;

[0120] (3) The three-arm star-shaped polyethylene glycol-polylactic acid block copolymer was electrospun to obtain a random dense membrane; in the three-arm star-shaped polyethylene glycol-polylactic acid block copolymer, the proportion of polyethylene glycol segments was 15 mol%;

[0121] The electrospinning process parameters include: voltage of 20 kV, spinning speed of 1 mL / h, receiving distance of 20 cm, spinning time of 2 h, needle diameter of 22 G, drum speed of 300 rpm; spinning solution concentration of 12 wt% and solvent of N,N-dimethylformamide;

[0122] (4) The random dense membrane obtained by electrospinning and the oriented fiber membrane after annealing are composited by ultrasonic welding to produce a double-layer composite patch with healing and repair functions;

[0123] Among them, the power of ultrasonic welding is 200W, the time is 2s, and the pressure is 0.3MPa.

[0124] The final double-layer composite patch with healing and repair function was composed of an oriented fiber layer and a random dense layer. In the macrophage polarization experiment, compared with the blank control group, the proportion of M1 macrophages decreased by 30% and the proportion of M2 macrophages increased by 20% after patch treatment. In the inflammatory factor detection experiment, compared with the inflammatory control group, the secretion of TNF-α, IL-6, and IL-1β inflammatory factors decreased by 50%, 52%, and 48%, respectively. Ten weeks after surgery, the maximum tensile force of the patch implantation group recovered to 75% of that of normal tissue, and the elastic modulus recovered to 65% of that of normal tissue. In the cell migration experiment, the number of migrating cells in the patch group was 110±10, which was an 83.30% increase compared with the blank control group. The cell density of the patch group was 380±50 cells / mm², and the continuous fiber was 83±7%.

[0125] Example 4

[0126] A method for preparing a double-layer composite patch with a healing and repairing function comprises the following steps:

[0127] (1) The weight average molecular weight is 10×10 4 Da of polylactic acid and a weight average molecular weight of 8×10 4 Type I collagen extracted from bovine Achilles tendon was electrospun to obtain an oriented fiber membrane; the mass ratio of polylactic acid to collagen in the oriented fiber membrane was 5:5;

[0128] The electrospinning process parameters included: voltage of 25 kV, spinning speed of 1.4 mL / h, receiving distance of 16 cm, spinning time of 2 h, needle diameter of 21 G, drum speed of 2600 rpm; spinning solution concentration of 10 wt % and solvent of acetic acid;

[0129] (2) The oriented fiber membrane obtained by electrospinning was cut into 50 mm × 60 mm pieces and pre-tensioned and placed in a bidirectional clamping device, and then the bidirectional clamping device was placed in a vacuum oven at 75 ° C for annealing;

[0130] Among them, the pre-tension is 0.8N; the heating rate during annealing is 4℃ / min, and the annealing time is 8h;

[0131] (3) A four-arm star-shaped polyethylene glycol-polylactic acid block copolymer was electrospun to obtain a random dense membrane; in the four-arm star-shaped polyethylene glycol-polylactic acid block copolymer, the proportion of polyethylene glycol segments was 25 mol%;

[0132] The electrospinning process parameters included: voltage of 15 kV, spinning speed of 0.6 mL / h, receiving distance of 16 cm, spinning time of 4 h, needle diameter of 20 G, drum speed of 400 rpm; spinning solution concentration of 10 wt % and solvent of acetic acid;

[0133] (4) The random dense membrane obtained by electrospinning and the oriented fiber membrane after annealing are composited by ultrasonic welding to produce a double-layer composite patch with healing and repair functions;

[0134] Among them, the power of ultrasonic welding is 250W, the time is 1.8s, and the pressure is 0.4MPa.

[0135] The final double-layer composite patch with healing and repair function was composed of an oriented fiber layer and a random dense layer. In the macrophage polarization experiment, compared with the blank control group, the proportion of M1 macrophages decreased by 45% and the proportion of M2 macrophages increased by 35% after patch treatment. In the inflammatory factor detection experiment, compared with the inflammatory control group, the secretion of TNF-α, IL-6, and IL-1β inflammatory factors decreased by 65%, 63%, and 67%, respectively. Nine weeks after surgery, the maximum tensile force of the patch implantation group recovered to 85% of that of normal tissue, and the elastic modulus recovered to 75% of that of normal tissue. In the cell migration experiment, the number of migrating cells in the patch group was 105±9, which was 75% higher than that in the blank control group. The cell density of the patch group was 330±35 cells / mm², and the continuous fiber ratio was 88±4%.

[0136] Example 5

[0137] A method for preparing a double-layer composite patch with a healing and repairing function comprises the following steps:

[0138] (1) The weight average molecular weight is 15×10 4 Da poly L-lactide-caprolactone and a weight average molecular weight of 8.5×10 4 Type I collagen extracted from bovine Achilles tendon was electrospun to obtain an oriented fiber membrane; the mass ratio of poly (L-lactide-caprolactone) to collagen in the oriented fiber membrane was 7:3;

[0139] The electrospinning process parameters included: voltage of 10 kV, spinning speed of 1.8 mL / h, receiving distance of 18 cm, spinning time of 5 h, needle diameter of 20 G, drum speed of 2800 rpm; spinning solution concentration of 7 wt % and solvent of chloroform;

[0140] (2) The oriented fiber membrane obtained by electrospinning was cut into 50 mm × 60 mm pieces and pre-tensioned and placed in a bidirectional clamping device, and then the bidirectional clamping device was placed in a vacuum oven at 80 ° C for annealing;

[0141] Among them, the pre-tension is 2N; the heating rate during annealing is 3℃ / min, and the annealing time is 2h;

[0142] (3) An eight-arm star-shaped polyethylene glycol-polylactic acid block copolymer was electrospun to obtain a random dense membrane; in the eight-arm star-shaped polyethylene glycol-polylactic acid block copolymer, the polyethylene glycol segment accounts for 40 mol%;

[0143] The electrospinning process parameters included: voltage of 10 kV, spinning speed of 0.1 mL / h, receiving distance of 10 cm, spinning time of 5 h, needle diameter of 21 G, drum speed of 500 rpm; spinning solution concentration of 7 wt % and solvent of chloroform;

[0144] (4) The random dense membrane obtained by electrospinning and the oriented fiber membrane after annealing are composited by ultrasonic welding to produce a double-layer composite patch with healing and repair functions;

[0145] Among them, the power of ultrasonic welding is 280W, the time is 1.5s, and the pressure is 0.5MPa.

[0146] The final double-layer composite patch with healing and repair function was composed of an oriented fiber layer and a random dense layer. In the macrophage polarization experiment, compared with the blank control group, the proportion of M1 macrophages decreased by 40% and the proportion of M2 macrophages increased by 30% after patch treatment. In the inflammatory factor detection experiment, compared with the inflammatory control group, the secretion of TNF-α, IL-6, and IL-1β inflammatory factors decreased by 60%, 62%, and 65%, respectively. 11 weeks after surgery, the maximum tensile force of the patch implantation group recovered to 80% of that of normal tissue, and the elastic modulus recovered to 70% of that of normal tissue. In the cell migration experiment, the number of migrating cells in the patch group was 125±11, which was 108.30% higher than that in the blank control group. The cell density of the patch group was 350±45 cells / mm², and the continuous fiber ratio was 85±6%.

[0147] Example 6

[0148] A method for preparing a double-layer composite patch with a healing and repairing function comprises the following steps:

[0149] (1) The weight average molecular weight is 6×10 4 Da polylactic acid - glycolic acid copolymer and weight average molecular weight of 10 × 10 4 The oriented fiber membrane was obtained by electrospinning type I collagen extracted from bovine Achilles tendon of Da; the mass ratio of polylactic acid-co-glycolic acid copolymer to collagen in the oriented fiber membrane was 6:4;

[0150] The electrospinning process parameters included: voltage of 20 kV, spinning speed of 2 mL / h, receiving distance of 20 cm, spinning time of 3 h, needle diameter of 22 G, and drum speed of 3000 rpm; the spinning solution concentration was 11 wt % and the solvent was a mixed solvent of N,N-dimethylformamide and acetic acid in a volume ratio of 1:1.

[0151] (2) The oriented fiber membrane obtained by electrospinning was cut into 50 mm × 60 mm pieces and pre-tensioned and placed in a bidirectional clamping device, and then the bidirectional clamping device was placed in a vacuum oven at 60 ° C for annealing;

[0152] The pre-tension is 1.2N; the heating rate during annealing is 5°C / min, and the annealing time is 22h;

[0153] (3) The three-arm star-shaped polyethylene glycol-polylactic acid block copolymer was electrospun to obtain a random dense membrane; in the three-arm star-shaped polyethylene glycol-polylactic acid block copolymer, the proportion of polyethylene glycol segments was 15 mol%;

[0154] The electrospinning process parameters included: voltage of 20 kV, spinning speed of 0.9 mL / h, receiving distance of 19 cm, spinning time of 2 h, needle diameter of 22 G, and drum speed of 200 rpm; the spinning solution concentration was 11 wt %, and the solvent was a mixed solvent of N,N-dimethylformamide and acetic acid in a volume ratio of 1:1.

[0155] (4) The random dense membrane obtained by electrospinning and the oriented fiber membrane after annealing are composited by ultrasonic welding to produce a double-layer composite patch with healing and repair functions;

[0156] Among them, the power of ultrasonic welding is 300W, the time is 1s, and the pressure is 0.1MPa.

[0157] The final double-layer composite patch with healing and repair function was composed of an oriented fiber layer and a random dense layer. In the macrophage polarization experiment, compared with the blank control group, the proportion of M1 macrophages decreased by 32% and the proportion of M2 macrophages increased by 22% after patch treatment. In the inflammatory factor detection experiment, compared with the inflammatory control group, the secretion of TNF-α, IL-6, and IL-1β inflammatory factors decreased by 53%, 55%, and 50%, respectively. Eight weeks after surgery, the maximum tensile force of the patch implantation group recovered to 72% of that of normal tissue, and the elastic modulus recovered to 72% of that of normal tissue. In the cell migration experiment, the number of migrating cells in the patch group was 95±8, which was 96.70% higher than that in the blank control group. The cell density of the patch group was 370±40 cells / mm², and the continuous fiber ratio was 84±5%.

Claims

1. A double-layer composite patch with healing and repair functions, characterized by: It is composed of an oriented fiber layer and a random dense layer composited up and down; The components of the oriented fiber layer are synthetic polymers and natural polymers, the synthetic polymer is polylactic acid, poly L-lactide-caprolactone or polylactic acid-glycolic acid copolymer, and the natural polymer is insoluble type I collagen; The random dense layer is composed of a polyethylene glycol-polylactic acid block copolymer with a star-shaped structure; In the star-shaped polyethylene glycol-polylactic acid block copolymer, the polyethylene glycol segment accounts for 15-40 mol%; The oriented fiber layer and the random dense layer are composited by ultrasonic welding.

2. The double-layer composite patch with the function of promoting healing and repair according to claim 1, characterized in that: The polyethylene glycol-polylactic acid block copolymer with a star structure is a three-arm star polyethylene glycol-polylactic acid block copolymer, a four-arm star polyethylene glycol-polylactic acid block copolymer or an eight-arm star polyethylene glycol-polylactic acid block copolymer.

3. The double-layer composite patch with the function of promoting healing and repair according to claim 1, characterized in that: The weight average molecular weight of the synthesized polymer is 5×10 4 ~15×10 4 Da, the weight average molecular weight of natural polymer is 5×10 4 ~10×10 4 Da.

4. The double-layer composite patch with the function of promoting healing and repair according to claim 1, characterized in that: The weight average molecular weight of the star-shaped polyethylene glycol-polylactic acid block copolymer is 5×10 4 ~20×10 4 Da.

5. The double-layer composite patch with the function of promoting healing and repair according to claim 1, characterized in that: The mass ratio of synthetic polymer to natural polymer in the oriented fiber layer is 4:6~8:

2.

6. The double-layer composite patch with the function of promoting healing and repair according to claim 1, characterized in that: The thickness of the oriented fiber layer is 0.1~0.5 mm, and the thickness of the random dense layer is 0.05~0.2 mm.

7. A method for preparing a double-layer composite patch with a healing and repairing function according to any one of claims 1 to 6, characterized in that The steps include: (1) Cutting the oriented fiber membrane obtained by electrospinning, pre-tensioning it and placing it in a bidirectional clamping device, and then placing the bidirectional clamping device in a vacuum oven for annealing; (2) The random dense membrane obtained by electrospinning and the oriented fiber membrane after annealing were composited by ultrasonic welding to produce a double-layer composite patch with healing and repair functions.

8. The method for preparing a double-layer composite patch with a healing and repairing function according to claim 7, characterized in that: The electrospinning process parameters for the oriented fiber layer include: voltage of 10-25 kV, spinning speed of 0.8-2 mL / h, receiving distance of 10-20 cm, spinning time of 2-5 h, needle diameter of 20-22 G, and drum speed of 2000-3000 rpm; The electrospinning process parameters for the random dense layer include: voltage of 10-20 kV, spinning speed of 0.1-1 mL / h, receiving distance of 10-20 cm, spinning time of 2-5 h, needle diameter of 20-22 G, and drum speed of 100-500 rpm; The spinning solution concentrations during electrospinning of the random dense layer and the oriented fiber layer were both in the range of 6~12wt%.

9. The method for preparing a double-layer composite patch with a healing and repairing function according to claim 7, characterized in that: In step (1), the annealing temperature is 60-80°C, the heating rate during annealing is 3-5°C / min, and the annealing time is 2-24h.

10. The method for preparing a double-layer composite patch with a healing and repairing function according to claim 7, characterized in that: In step (2), the power of ultrasonic welding is 100~300 W, the time is 1~3 s, and the pressure is 0.1~0.5 MPa.

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