Multi-stage synergistic wound repair nanofiber membrane and preparation method thereof

Abstract

The invention provides a multi-stage synergistic wound repair nanofiber membrane and a preparation method thereof. The composite fiber membrane sequentially comprises an electrostatic spinning pullulan / tannic acid / tranexamic acid nanofiber membrane for promoting the formation of blood clots, a polydopamine / calcium chloride modified electrostatic spinning cellulose acetate membrane with coagulating, antibacterial and repairing effects, and a chitosan composite cellulose non-woven fabric, and the electrostatic spinning pullulan / tannic acid / tranexamic acid nanofiber membrane is a wound surface contact layer. The nanofiber membrane has the functions of a physical hemostasis barrier and continuously releasing regeneration promoting biological signals, and a dynamic hemostasis healing process is formed.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials technology, specifically relating to a multi-level synergistic wound repair nanofiber membrane and its preparation method. Background Technology

[0002] Skin wound healing is a dynamic, multi-stage, and complex process encompassing hemostasis, inflammation, proliferation, and remodeling. Hemostasis, as the initial stage, forms a blood clot that serves not only as a physical barrier but also as a temporary extracellular matrix rich in bioactive signals, providing an indispensable microenvironment for subsequent repair stages.

[0003] In recent years, various novel hemostatic materials (such as porous sponges and mineral fibers) have been developed to achieve rapid initial hemostasis. Simultaneously, numerous active dressings (such as hydrogels and electrospun fiber membranes) have been designed to mimic the extracellular matrix structure, aiming to directly promote cell proliferation and migration, and accelerate the healing process. However, existing research exhibits a clear functional divide: research on hemostatic materials focuses primarily on the blood flow control stage, with "achieving rapid hemostasis" as the endpoint; while research on healing-promoting materials is generally based on a "clean" wound after debridement, starting after the hemostasis stage. This lack of effective connection between these two research paths leads to a discontinuity in the healing process in terms of both time and function. Particularly noteworthy is the insufficient attention and utilization of the crucial "material-blood interaction interface" stage in current technologies. Specifically, when a hemostatic material comes into contact with blood, the resulting complex blood clot is no longer a simple blood component but a novel biocomposite structure carrying the material's own physicochemical properties. This structure, acting as a natural bridge connecting the material's initial function and subsequent biological response, has a continuous impact on the healing process due to its composition, structure, and biological characteristics. Currently, there is a lack of systematic research exploring how to actively regulate the properties of the blood clot through material design, thereby transforming it from a passively formed hemostatic end product into a dynamic bioactive platform that can actively guide subsequent cell behavior and promote regeneration and repair. This has become an unresolved technical blind spot in the field of wound treatment materials. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides a multi-level synergistic wound repair nanofiber membrane and its preparation method, which combines the functions of a physical hemostatic barrier and the continuous release of regenerative biological signals to form a dynamic hemostasis and healing process.

[0005] The technical problem solved by this invention is achieved by the following technical solution:

[0006] The first objective of this invention is to provide a multi-level synergistic wound repair nanofiber membrane, which sequentially comprises an electrospun pullulan / tannic acid / tranexamic acid nanofiber membrane that promotes blood clot formation, an electrospun cellulose acetate membrane modified with polydopamine / calcium chloride that has coagulation, antibacterial and repairing effects, and a chitosan composite cellulose nonwoven fabric, wherein the electrospun pullulan / tannic acid / tranexamic acid nanofiber membrane is the wound contact layer.

[0007] The present invention discloses the release of TA / TXA from the Pull / TA / TXA membrane layer after the nanofiber membrane absorbs plasma, and the release of Ca from the modified CA membrane layer. 2+ PDA synergistically concentrates red blood cells, platelets, and fibrinogen to form a stable bioactive blood clot complex, optimizing the protein assembly process. It not only has a stable physical barrier function, but also effectively upregulates the expression levels of proteins related to key wound healing processes such as angiogenesis, fibroblast proliferation, and re-epithelialization by regulating the composition and spatial distribution of extracellular matrix-related proteins. This achieves rapid hemostasis while continuously promoting the subsequent wound healing process, realizing seamless connection and active biological regulation in both time and space from the hemostasis stage to the healing stage.

[0008] Furthermore, the electrospun pullulan / tannic acid / tranexamic acid nanofiber membrane is prepared by electrospinning pullulan / tannic acid / tranexamic acid spinning solution.

[0009] Furthermore, the polydopamine / calcium chloride modified electrospun cellulose acetate membrane is obtained by immersing an electrospun cellulose acetate membrane in a polydopamine / calcium chloride mixed solution and reacting for 20-50 minutes, followed by drying.

[0010] Furthermore, the chitosan composite cellulose nonwoven fabric is obtained by uniformly coating the surface of cellulose spunlace fabric with a CS solution.

[0011] The second objective of this invention is to provide a method for preparing a multi-level synergistic wound repair nanofiber membrane, comprising the following steps:

[0012] S1. Preparation of polydopamine / calcium chloride modified electrospun cellulose acetate membrane: polydopamine / calcium chloride modified electrospun cellulose acetate membrane was obtained by electrospinning, and then treated in an oven overnight to remove residual organic solvents before use.

[0013] S2. Preparation of chitosan composite cellulose nonwoven fabric: Prepare an acetic acid aqueous solution of CS and uniformly coat the surface of cellulose spunlace fabric with the prepared acetic acid aqueous solution of CS; immediately after coating, lay the electrospun cellulose acetate membrane modified with polydopamine / calcium chloride obtained in S1 on the coated surface, and then dry the laid material to form a composite membrane.

[0014] Preparation of S3 and MCNM: Pull, TA and TXA are mixed and dissolved in water to obtain Pull / TA / TXA composite spinning solution, and the composite spinning solution is directly spun onto the composite membrane substrate obtained in S2 to obtain the multi-level synergistic wound repair nanofiber membrane.

[0015] Furthermore, the preparation method of polydopamine / calcium chloride modified electrospun cellulose acetate membrane is as follows: after obtaining an electrospun cellulose acetate membrane by electrospinning CA spinning solution, the electrospun cellulose acetate membrane is immersed in a polydopamine / calcium chloride mixed solution and reacted for 20-50 min, and then dried to obtain the polydopamine / calcium chloride modified electrospun cellulose acetate membrane.

[0016] Furthermore, the preparation method of the electrospun cellulose acetate membrane in step S1 is as follows: acetone and N,N-dimethylformamide are configured into a binary solvent system, and then CA powder is added to obtain a CA spinning solution with a mass-volume concentration of 12-25% (w / v), and then electrospinning is performed to obtain an electrospun cellulose acetate membrane.

[0017] Furthermore, the preparation method of polydopamine / calcium chloride modified electrospun cellulose acetate membrane is as follows: dopamine and CaCl2 are dissolved in deionized water to obtain a mixed solution with a mass-volume concentration of 1% (w / v). The pH value is adjusted to 8-9 under stirring, and the solution is stirred until it turns black to obtain a polydopamine / calcium chloride mixed solution. Then, the electrospun cellulose acetate membrane is immersed in the mixed solution and reacted for 20-50 min. After drying, the polydopamine / calcium chloride modified electrospun cellulose acetate membrane is obtained.

[0018] Furthermore, the preparation method of polydopamine / calcium chloride modified electrospun cellulose acetate membrane is as follows: the CA spinning solution is mixed with DA and CaCl2, the pH is adjusted to 8-9 to obtain a uniform spinning precursor solution, and then electrospinning is performed to obtain polydopamine / calcium chloride modified electrospun cellulose acetate membrane.

[0019] Furthermore, the preparation method of polydopamine / calcium chloride modified electrospun cellulose acetate membrane is as follows: acetone and N,N-dimethylformamide are prepared into a binary solvent system, and then CA powder is added to obtain a CA spinning solution with a mass-volume concentration of 12-18% (w / v); then DA and CaCl2 are added to the CA spinning solution and mixed to obtain a mixed solution with a mass-volume concentration of 1% (w / v). The pH of the solution is adjusted to 8-9 under stirring, and stirring is continued for 1 hour to obtain a homogeneous spinning precursor solution. Then, electrospinning is performed to obtain a polydopamine / calcium chloride modified electrospun cellulose acetate membrane.

[0020] Furthermore, the electrospinning process parameters are: spinning voltage 15–25 kV, receiving distance 10–20 cm, and solution flow rate 0.5–0.8 mL / h. Preferably, the electrospinning process parameters are: spinning voltage 18 kV, receiving distance 15 cm, and solution flow rate 0.6 mL / h.

[0021] Furthermore, the volume ratio of acetone to N,N-dimethylformamide is 1.5 to 2.5:1. Preferably, the volume ratio of acetone to N,N-dimethylformamide is 2:1.

[0022] Furthermore, the pH of the solution is adjusted using sodium hydroxide solution or Tris-HCl buffer.

[0023] Furthermore, in step S2, the acetic acid aqueous solution of CS is obtained by dissolving CS in an acetic acid aqueous solution with a volume fraction of 1%, and the mass-volume concentration of the acetic acid aqueous solution of CS is 4-6% (w / v).

[0024] Furthermore, the concentration of Pull in the Pull / TA / TXA composite spinning solution is 25-35% (w / v), the concentration of TA is 0.5-1.5% (w / v), and the concentration of TXA is 0.5-1.5% (w / v).

[0025] Preferably, the concentration of Pull in the Pull / TA / TXA composite spinning solution is 30% (w / v), the concentration of TA is 1% (w / v), and the concentration of TXA is 1% (w / v).

[0026] Furthermore, the electrospinning process parameters in step S3 are: spinning voltage 20–30 kV, receiving distance 10–20 cm, and solution flow rate 0.2–0.4 mL / h. Preferably, the electrospinning process parameters in step S3 are: spinning voltage 25 kV, receiving distance 15 cm, and solution flow rate 0.3 mL / h.

[0027] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0028] The multi-level synergistic wound repair nanofiber membrane of this invention has a first layer that directly contacts the wound: an electrospun pullulan / tannic acid / tranexamic acid (Pull / TA / TXA) nanofiber membrane; a second middle layer that is a polydopamine (PDA) / calcium chloride (CaCl2) modified electrospun cellulose acetate (CA) membrane; and an outermost third layer that is a chitosan (CS) composite cellulose nonwoven fabric. During use, the third layer of cellulose spunlace fabric absorbs excess liquid, the Pull / TA / TXA membrane layer dissolves and releases TA / TXA, and the modified CA membrane layer releases Ca... 2+ / PDA forms a synergistic effect, TA rapidly constricts blood vessels and binds to fibrinogen to form a dense network that promotes platelet aggregation, TXA inhibits fibrinolysis and prolongs clot life, and the modified CA membrane's Ca 2+ It promotes blood coagulation, effectively concentrates platelets, erythrocytes, and fibrinogen, and ultimately forms a structurally enhanced bioactive blood clot that promotes hemostasis with a short hemostasis time. Introducing CS as a functional adhesive layer between the layers not only significantly enhances the interlayer bonding strength and avoids delamination during use, but also endows the composite membrane with excellent antibacterial properties, thus expanding its application potential in the biomedical field. Through optimization of electrospinning parameters, a Pull / TA / TXA nanofiber membrane with good morphology and uniform structure was successfully obtained.

[0029] When applied to bleeding wounds, the multi-level synergistic wound repair nanofiber membrane of this invention can rapidly absorb plasma components, effectively concentrate red blood cells, platelets, and fibrinogen, and thus form a stable bioactive blood clot complex. The blood clot complex has both the function of a physical hemostatic barrier and the ability to continuously release regenerative biological signals. While inhibiting bleeding, it repairs the wound skin and promotes wound healing, breaking through the limitations of traditional materials with single functions. It provides a new strategy for developing intelligent wound repair materials with both rapid hemostasis and continuous healing promotion functions.

[0030] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating the preparation process of the multi-level synergistic wound repair nanofiber membrane of the present invention.

[0032] Figure 2 This is a schematic diagram illustrating the application principle of the multi-level synergistic wound repair nanofiber membrane of the present invention.

[0033] Figure 3 The images show the SEM and EDS analysis results of the PDA / CaCl2 modified CA membrane obtained in Example 1 of this invention.

[0034] Figure 4 The images show the SEM and EDS analysis results of the Pull / TA / TXA composite fiber membrane obtained in Example 1 of this invention.

[0035] Figure 5 The images show the FTIR infrared spectra and XPS energy dispersive spectroscopy of the electrospun CA fiber membrane, the PDA / CaCl2 modified CA membrane, and the Pull / TA / TXA composite fiber membrane obtained in Example 1 of this invention.

[0036] Figure 6 The water contact angle test diagrams are of the electrospun CA fiber membrane and the PDA / CaCl2 modified CA membrane obtained in Example 1 of the present invention.

[0037] Figure 7 The images show the material and blood contact behavior test diagrams of the electrospun CA fiber membrane, PDA / CaCl2 modified CA membrane, and MCNM fiber membrane obtained in Example 1 of this invention. Detailed Implementation

[0038] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0039] In addition, unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be obtained by purchasing them from the market or prepared by existing methods.

[0040] Example 1

[0041] See appendix Figure 1 A method for preparing a multi-level synergistic wound repair nanofiber membrane includes the following steps:

[0042] S1. Preparation of polydopamine / calcium chloride modified electrospun cellulose acetate membrane:

[0043] First, acetone and N,N-dimethylformamide were mixed at a volume ratio of 2:1 to prepare a binary solvent system. Then, CA powder was added to achieve a mass-volume concentration of 15% (w / v). The mixture was stirred continuously at room temperature for 30 minutes to obtain a homogeneous CA spinning solution. Next, using a syringe equipped with a 21G needle, the CA spinning solution was electrospun under the following process parameters: voltage 18kV, receiving distance 15cm, and solution flow rate 0.6mL / h. Aluminum foil was used as a grounded collector during the spinning process. After spinning for 12 hours, an electrospun CA fiber membrane was obtained. The CA fiber membrane was then placed in a 45°C oven overnight to completely remove residual organic solvents. Then, dopamine (DA) and CaCl2 were dissolved in deionized water to prepare mixed solutions with a mass-volume concentration of 1% (w / v) each, and the mixture was stirred continuously for 6 hours. The pH of the mixed solution was adjusted to 8.5 using sodium hydroxide solution, and stirring was continued for 1 hour. Once the solution turns black, it indicates that PDA has been successfully generated in situ. Finally, the electrospun CA membrane prepared above is immersed in the PDA / CaCl2 mixed solution for 30 minutes, then removed and dried in an oven overnight to obtain the PDA / CaCl2 modified CA membrane.

[0044] Preparation of composite membrane materials of S2 and CS adhesive cellulose spunlace fabric and PDA / CaCl2 modified CA membrane:

[0045] CS was dissolved in a 1% (v / v) aqueous solution of acetic acid to prepare a 4% (w / v) CS solution. The solution was then stirred continuously in a 60°C water bath for 4 hours to ensure complete dissolution, resulting in a homogeneous and transparent CS adhesive solution. Subsequently, a thin layer of the CS solution was uniformly coated onto the surface of a cellulose spunlace fabric, and the PDA / CaCl2-modified CA membrane prepared in step S1 was immediately deposited onto the coated surface. Finally, the resulting laminated structure was placed in a 45°C oven for 30 minutes to complete drying and interfacial bonding, thereby obtaining a composite membrane material with strong interlayer bonding.

[0046] Preparation of S3 and MCNM:

[0047] Using water as a solvent, Pull, TA, and TXA were added sequentially, and the mixture was stirred continuously for 24 hours until completely dissolved and homogeneous, thus obtaining a Pull / TA / TXA composite spinning solution. The concentrations of Pull, TA, and TXA were 30% (w / v), TA, and TXA, respectively. Subsequently, using a syringe equipped with a 20G needle, the obtained composite spinning solution was directly applied to the composite membrane material substrate prepared in step S2 under electrospinning parameters of 25kV voltage, 15cm receiving distance, and 0.3mL / h solution flow rate, ultimately yielding a multilayer nanofiber membrane.

[0048] Example 2

[0049] Unlike Example 1, the preparation process of the polydopamine / calcium chloride modified electrospun cellulose acetate membrane is different.

[0050] The preparation process of polydopamine / calcium chloride modified electrospun cellulose acetate membrane is as follows:

[0051] Acetone and N,N-dimethylformamide were mixed at a volume ratio of 2:1 to prepare a binary solvent system. CA powder was then added to prepare a 15% (w / v) mixed solution. The solution was stirred continuously at room temperature for 30 minutes to obtain a homogeneous CA spinning solution. Subsequently, DA and CaCl2 were added to the spinning solution to achieve a 1% (w / v) concentration for both. The pH of the system was adjusted to 8.5 using Tris-HCl buffer solution, and stirring was continued for 1 hour to obtain a homogeneous spinning precursor solution. Next, electrospinning was performed on the spinning solution using a syringe equipped with a 21G needle at process parameters of 18 kV, a receiving distance of 15 cm, and a solution flow rate of 0.6 mL / h. Aluminum foil was used as a grounded collector during the spinning process. After 12 hours of continuous spinning, an electrospun PDA / CaCl2 modified CA fiber membrane was obtained. Subsequently, the fiber membrane was placed in a 45°C oven overnight to completely remove residual organic solvents, thus obtaining a PDA / CaCl2 modified CA membrane.

[0052] Experimental Example

[0053] 1. Morphology of nanofiber membranes

[0054] The PDA / CaCl2 modified CA film obtained in step S1 of Example 1 was scanned by SEM and its elemental distribution was analyzed by EDS.

[0055] See appendix Figure 3 It can be seen that the PDA / CaCl2 modified CA membrane fibers have complete morphology, continuous structure, and uniform overall texture, exhibiting a three-dimensional porous network structure. N and Ca elements are uniformly distributed on the membrane surface, indicating that PDA and CaCl2 are successfully loaded onto the CA fiber membrane surface.

[0056] The surface of the nanofiber membrane obtained in Example 1 (i.e., the Pull / TA / TXA composite fiber membrane) was scanned by SEM and the elemental distribution was analyzed by EDS.

[0057] See appendix Figure 4 As can be seen, the nanofiber membrane has a complete morphology, continuous structure, and uniform overall texture, exhibiting a three-dimensional porous network structure. The C, O, and N elements on the membrane surface are all uniformly distributed. (See appendix) Figure 5 ,

[0058] FTIR and XPS energy dispersive spectroscopy analyses were performed on the electrospun CA fiber membrane, PDA / CaCl2 modified CA membrane, and Pull / TA / TXA composite fiber membrane obtained in Example 1, respectively. (See Appendix) Figure 5As can be seen, the characteristic functional group signals of each component in the FTIR infrared spectrum were detected, indicating successful assembly; the characteristic peaks in the XPS energy dispersive spectroscopy analysis also reflect successful assembly.

[0059] 2. Hydrophilicity test of PDA / CaCl2 modified CA membrane

[0060] The hydrophilic and hydrophobic properties of the CA membrane and the PDA / CaCl2 modified CA membrane were characterized by water contact angle testing. (See appendix) Figure 6 The results showed that the unmodified CA film exhibited hydrophobic properties with a static water contact angle of 119°; however, after modification with PDA / CaCl2, the surface properties of the material became hydrophilic, with an initial contact angle of 59°, and water droplets could spread completely within 3 seconds, with the contact angle dropping to 0°, demonstrating excellent instantaneous wetting performance.

[0061] 3. Coagulation performance testing

[0062] The CA fiber membrane, PDA / CaCl2 modified CA membrane, and multi-level synergistic wound repair nanofiber membrane samples obtained in Example 1 were suspended and fixed in the air with clamps. Blood was dripped from top to bottom, and the bottom surface was wiped off with toilet paper immediately after 3 seconds to observe the blood absorption and adhesion.

[0063] See appendix Figure 7 As can be seen, the CA membrane surface exhibits significant blood repellency characteristics, with no permeability or spreadability observed. The CA membrane modified with PDA / CaCl2, however, exhibits rapid blood infiltration behavior and selective permeability, effectively blocking solid components such as blood cells on the membrane surface while simultaneously guiding the rapid removal of plasma water. In this embodiment of the invention, when the MCNM fiber membrane comes into contact with blood, its surface Pull / TA / TXA membrane rapidly adsorbs blood and promotes its spread, thereby initiating the coagulation process and forming a blood clot complex on the surface of the MCNM fiber membrane. The underlying cellulose spunlace fabric simultaneously plays a role in liquid absorption and water retention, jointly optimizing the coagulation microenvironment. Compared to the CA membrane modified with PDA / CaCl2 alone, although both can form blood clots for effective hemostasis, the CA membrane modified with PDA / CaCl2 primarily achieves hemostasis through CaCl2. 2+ The previous method promoted coagulation and hemostasis, but the hemostasis time was long, and some blood was absorbed by the sample, forming a uniform and loose blood clot on the sample surface. In contrast, the MCNM fiber membrane of this application rapidly promotes platelet aggregation under the action of TA, and TXA inhibits fibrinolysis, resulting in more blood fusion Ca. 2+ It has a coagulant effect, a short hemostasis time, and forms a thick blood clot on the sample surface with no obvious bleeding.

[0064] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0065] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A multi-level synergistic wound repair nanofiber membrane, characterized in that: The product comprises, in sequence, an electrospun pullulan / tannic acid / tranexamic acid nanofiber membrane that promotes blood clot formation, an electrospun cellulose acetate membrane modified with polydopamine / calcium chloride that has coagulation, antibacterial and repairing effects, and a chitosan composite cellulose nonwoven fabric. The electrospun pullulan / tannic acid / tranexamic acid nanofiber membrane serves as the wound contact layer.

2. The multi-level synergistic wound repair nanofiber membrane as described in claim 1, characterized in that: The electrospun pullulan / tannic acid / tranexamic acid nanofiber membrane is prepared by electrospinning pullulan / tannic acid / tranexamic acid spinning solution.

3. The multi-level synergistic wound repair nanofiber membrane as described in claim 1, characterized in that: The polydopamine / calcium chloride modified electrospun cellulose acetate membrane is obtained by immersing an electrospun cellulose acetate membrane in a polydopamine / calcium chloride mixed solution and reacting for 20-50 minutes, followed by drying.

4. The method for preparing a multi-level synergistic wound repair nanofiber membrane according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Preparation of polydopamine / calcium chloride modified electrospun cellulose acetate membrane: polydopamine / calcium chloride modified electrospun cellulose acetate membrane was obtained by electrospinning, and then treated in an oven overnight to remove residual organic solvents before use. S2. Preparation of chitosan composite cellulose nonwoven fabric: Prepare an acetic acid aqueous solution of CS and uniformly coat the surface of cellulose spunlace fabric with the prepared acetic acid aqueous solution of CS; immediately after coating, lay the electrospun cellulose acetate membrane modified with polydopamine / calcium chloride obtained in S1 on the coated surface, and then dry the laid material to form a composite membrane. Preparation of S3 and MCNM: Pull, TA and TXA are mixed and dissolved in water to obtain Pull / TA / TXA composite spinning solution, and the composite spinning solution is directly spun onto the composite membrane substrate obtained in S2 to obtain the multi-level synergistic wound repair nanofiber membrane.

5. The method for preparing a multi-level synergistic wound repair nanofiber membrane as described in claim 4, characterized in that, The preparation method of polydopamine / calcium chloride modified electrospun cellulose acetate membrane is as follows: after obtaining electrospun cellulose acetate membrane by electrospinning CA spinning solution, the electrospun cellulose acetate membrane is immersed in polydopamine / calcium chloride mixed solution and reacted for 20-50 min, and then dried to obtain polydopamine / calcium chloride modified electrospun cellulose acetate membrane.

6. The method for preparing a multi-level synergistic wound repair nanofiber membrane as described in claim 5, characterized in that... The preparation method of electrospun cellulose acetate membrane in step S1 is as follows: acetone and N,N-dimethylformamide are configured into a binary solvent system, and then CA powder is added to obtain a CA spinning solution with a mass-volume concentration of 12-25% (w / v). Then, electrospinning is performed to obtain an electrospun cellulose acetate membrane.

7. The method for preparing a multi-level synergistic wound repair nanofiber membrane as described in claim 4, characterized in that, The preparation method of polydopamine / calcium chloride modified electrospun cellulose acetate membrane is as follows: the CA spinning solution is mixed with DA and CaCl2, the pH is adjusted to 8-9 to obtain a homogeneous spinning precursor solution, and then electrospinning is performed to obtain polydopamine / calcium chloride modified electrospun cellulose acetate membrane.

8. The method for preparing a multi-level synergistic wound repair nanofiber membrane as described in claim 5 or 7, characterized in that: The electrospinning process parameters are: spinning voltage 15-25kV, receiving distance 10-20cm, and solution flow rate 0.5-0.8mL / h.

9. The method for preparing a multi-level synergistic wound repair nanofiber membrane as described in claim 4, characterized in that: The concentration of Pull in the Pull / TA / TXA composite spinning solution is 25-35% (w / v), the concentration of TA is 0.5-1.5% (w / v), and the concentration of TXA is 0.5-1.5% (w / v).

10. The method for preparing a multi-level synergistic wound repair nanofiber membrane as described in claim 4, characterized in that: The electrospinning process parameters in step S3 are: spinning voltage 20-30kV, receiving distance 10-20cm, and solution flow rate 0.2-0.4mL / h.

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