CN111588900B

CN111588900B - Waterproof, breathable, high-elasticity, self-repairing double-layer nanofiber membrane for skin dressing and its preparation method

Info

Publication number: CN111588900B
Application number: CN202010433183.1A
Authority: CN
Inventors: 李晓然; 郑玉琦; 周文; 帕维尔·纳基尔斯基; 基亚拉·里诺迪; 菲利波·皮耶里尼; 丁彬; 俞建勇
Original assignee: Donghua University
Current assignee: Donghua University
Priority date: 2020-05-21
Filing date: 2020-05-21
Publication date: 2021-06-18
Anticipated expiration: 2040-05-21
Also published as: CN111588900A

Abstract

The invention relates to a waterproof, breathable, high-elasticity, self-repairing double-layer nanofiber membrane for skin dressings and a preparation method thereof. First, a precursor composed of a synthetic polymer solution, an alcohol-soluble hydrophobic agent, an environment-friendly cross-linking agent and a functional drug is spun. The hydrophobic fiber membrane was obtained by electrospinning the silk solution I, and then the precursor spinning solution II, which consisted of natural polymer solution, catechol-based molecular solution and anhydrous ferric chloride powder, was electrospun and received in a hydrophobic solution. The composite fiber membrane is prepared on the fiber membrane, and finally the composite fiber membrane is obtained by post-processing; the water pressure resistance of the prepared double-layer nanofiber membrane is 5-50 kPa, the air permeability is 5-15 kg/m ² /d, and the elastic modulus is 5-50 kPa. The amount is 5-15MPa, and the tensile strength and elongation at break of the fiber membrane after self-healing are 50-90% of the initial value, which can improve the dressing's ability to promote healing while ensuring the fit and comfort of the wound.

Description

Waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for skin dressing and preparation method thereof

Technical Field

The invention belongs to the technical field of biomedical materials, and relates to a waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for skin dressing and a preparation method thereof.

Background

According to statistics, tens of millions of people in China cause skin wounds due to natural disasters or accidents every year. The traditional dressing has limited absorption capacity, needs frequent replacement and is easy to cause serious dehydration on the surface of a wound, thereby being not beneficial to the quick and effective healing of the wound surface. Compared with the traditional dressing with various defects, the high-end dressing based on the moist wound healing theory is widely accepted as an effective mode for promoting wound healing. However, China is weak in the aspects of research, development and production of high-end dressings, and high-end dressings which are efficient in promoting wound healing and good in comfort are urgently needed to be developed.

The dressing with the characteristics of water resistance, air permeability and high elasticity can prevent external water drops from permeating into a wound, and wound exudates and the like can be conducted to the outside in a water vapor mode, so that the wound is not easy to infect and can be used at flexible positions such as joints. Tegaderm manufactured by 3M company of America using Polyurethane (PU)^TMFilm dressing having a certain water resistance and a low air permeability of about 1.2kg/m²And d. Domestic patent discloses an in-situ crosslinking type I collagen electrospun fiber dressing and a preparation method thereof, wherein a natural crosslinking agent (oxidized sodium alginate) with good biocompatibility is adopted to participate in the electrostatic spinning process of collagen and in-situ crosslink type I collagen, and the electrospun fiber dressing is obtained through post-treatment; the dressing prepared by the method has good biocompatibility, no cytotoxicity and high bioactivity, but has poor elasticity and greatly limited application range.

Natural polymer materials are various in types and rich in resources, and have very similar structures to organisms. The natural polymer nanofiber dressing prepared by the electrostatic spinning technology has high porosity, large length-diameter ratio and large specific surface area, is highly fitted with extracellular matrix in size and structure, is favorable for adhesion, proliferation and tissue regeneration of cells, promotes transmission of nutrient substances and discharge of metabolites, and can effectively reduce scar generation; however, the mechanical strength of the dressing is poor, and when part of fibers are broken by external force, the adhesion of the dressing and the skin is reduced, so that the absorption of seepage, the transmission of nutrient substances and the healing of wound surfaces are delayed. Therefore, the intrinsic self-repairing performance of the fiber dressing is needed to be endowed, namely self-repairing is realized through the molecular structure of reversible chemical reaction in the polymer material. Therefore, the self-repair of materials by constructing a dynamic reversible covalent bond or non-covalent bond system becomes a research hotspot of polymer science. Mussel byssus as a special biological adhesion system has very high hardness, elasticity and self-repairing function, and the excellent self-repairing performance is considered to be caused by the dynamic reversible coordination action of catechol groups and metal ions and the reversible hydrogen bond interaction between the catechol groups. The researchers inspired by the above technology synthesize a series of double-network hydrogels with water content more than 95%, printing survival rate more than 90%, breaking strength more than 5MPa after curing, compressive modulus about 0.7MPa, and breaking elongation more than or equal to 400% for biological 3D printing. However, the hydrogel dressing is of a bulk structure, and the cell adhesion is not good, so that the hydrogel dressing is not beneficial to the growth of cells and the transmission of substances such as oxygen and the like.

Therefore, the research on the double-layer nanofiber membrane for the skin dressing, which integrates high elasticity, waterproof, breathable and self-repairing performances, and the preparation method thereof have very important significance.

Disclosure of Invention

The invention aims to solve the problems that a double-layer nanofiber dressing in the prior art cannot integrate high elasticity, waterproof air permeability and self-repairing performance and cannot meet different healing requirements of various wound types, and provides a waterproof air permeability high elasticity self-repairing double-layer nanofiber membrane for a skin dressing and a preparation method thereof. The waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing, which is prepared by the invention, can regulate and control the fiber aperture (0.2-2.0 mu m), the porosity (20-80%) according to the wound surface type,The crosslinking degree and other parameters are further adjusted to adjust the water pressure resistance (10-100 kPa) and the water vapor transmission (2-2.5 kg/m)²The elastic modulus (5-15 MPa), the elastic recovery rate (70-99%) and the like, and the healing promoting property and the bonding property of the dressing are effectively improved. The bionic mussel is chemically applied to the preparation of the fiber dressing, and catechol-based molecules (dopamine, tannic acid or tea polyphenol) with good biocompatibility and transition metal ions Fe are adopted³⁺Coordinately crosslinking natural polymer nanofibers, constructing multiple bonding networks (covalent bonds, coordination bonds and hydrogen bonds) between double-layer fiber membranes, synthesizing covalent bonds and hydrogen bonds between the polymer nanofibers and catechol-based molecules, and performing the functions of the natural polymer nanofibers and Fe³⁺Coordination between natural polymer nano-fiber and catechol-based molecule, covalent bond and hydrogen bond between natural polymer nano-fiber and catechol-based molecule, and catechol-based molecule and Fe³⁺The metal coordination between the two layers can endow the inner layer fiber film with self-repairing performance and improve the interlayer bonding force. According to the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing, the outer layer can block external moisture from permeating inwards, so that a proper healing environment is ensured, and mechanical support is provided; the inner layer has hydrophilicity and self-repairing property, when the dressing is subjected to external force, the fiber part of the inner layer is broken, and rapid self-repairing can be realized, so that the adhesiveness and long-term use of the dressing are ensured; multiple bonding effects (specifically, covalent bond and hydrogen bond effects between synthetic polymer nanofiber and catechol-based molecules, covalent bond and hydrogen bond effects between natural polymer nanofiber and catechol-based molecules) are formed between the two layers, and a small amount of catechol-based molecules and Fe exist³⁺Free between the two layers, so there are also catechol-based molecules and Fe³⁺Metal coordination between) improves interlayer adhesion. The double-layer nanofiber membrane can ensure the fitting property and comfort of a wound surface while promoting the healing promotion capability of the dressing, and has a wide application prospect in the field of medical skin dressings.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a skin dressing is with waterproof ventilative high-elastic selfreparing double-deck nanofiber membrane, the outer layer is waterproof ventilative high-elastic layer, can effectively obstruct the infiltration of external moisture, guarantee the suitable healing environment and provide the mechanical support, the inner layer is a hydrophilic self-repairing layer, have hydrophilicity and self-repairability concurrently, when the dressing is applied to the external force, the fiber part of the inner layer breaks and can realize the fast selfreparation, in order to guarantee the adhesiveness and long-term usability of the dressing;

the waterproof breathable high-elastic layer consists of a synthetic polymer fiber matrix, an alcohol-soluble hydrophobic agent, an environment-friendly cross-linking agent and a functional drug; wherein, the alcohol-soluble hydrophobic agent, the environment-friendly cross-linking agent and the functional drug are uniformly distributed on the synthetic polymer fiber matrix, and the environment-friendly cross-linking agent and the synthetic polymer fiber form a cross-linked network; the hydrophilic self-repairing layer is composed of a natural polymer fiber matrix, catechol-based molecules and Fe³⁺Composition is carried out; wherein the catechol-based molecule and Fe³⁺The polymer fiber is uniformly distributed on a natural polymer fiber matrix and forms a dynamic reversible crosslinking network with the natural polymer fiber;

the catechol-based molecules are dopamine, tannic acid or tea polyphenol;

the test method and the index range of the performance of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are as follows: the water pressure resistance of the fiber membrane is represented by a fabric water permeability tester to be 5-50 kPa, and the air permeability of the fiber membrane is represented by a fabric water permeability tester to be 5-15 kg/m²A single fiber strength tester is adopted to represent that the tensile strength of the fiber membrane is 5-15 MPa and the elongation at break is 50-400%, a universal testing machine is adopted to represent that the elastic modulus of the fiber membrane is 5-15 MPa and the elastic recovery rate is 60-99%; the tensile strength and the elongation at break of the fiber membrane after self-repairing are 50-90% of the initial (when not damaged) by adopting a single-fiber strength instrument.

Catechol-based molecules (dopamine, tannic acid and tea polyphenol) with good biocompatibility and natural polymer, and transition metal ion Fe³⁺Multiple bonding actions (covalent bonds, coordination bonds and hydrogen bonds) are generated, wherein the coordination bonds and the hydrogen bonds are reversible, so that self-repairing performance is endowed to the inner layer fibers, and the adhesion force between the double-layer fiber film layers is improved.

As a preferred technical scheme:

the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing comprises synthetic macromolecules, wherein the synthetic macromolecules are waterborne polyurethane, waterborne acrylic resin, polyvinylpyrrolidone or polyvinyl butyral; the alcohol-soluble hydrophobic agent is more than one of hydrogen-containing silicone oil, polymethylhydrosiloxane emulsion and polydimethylsiloxane emulsion; the environment-friendly cross-linking agent is an epoxy silane cross-linking agent, an organosilane cross-linking agent, a closed isocyanate cross-linking agent or polycarbodiimide; the functional medicine is curcumin, diclofenac sodium, warfarin, ferulic acid or aspirin; the natural polymer is gelatin or chitosan.

The waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing has the advantages that the fiber diameter of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 100-2000 nm, the fiber length-diameter ratio is 10-10000, the pore diameter is 0.2-2.0 mu m, and the porosity is 20-80%;

the outer water pressure resistance of the waterproof, breathable, high-elastic and self-repairing double-layer nanofiber membrane for the skin dressing is 10-100 kPa, and the breathability is 5-15 kg/m²The tensile strength is 5-20 MPa, the elongation at break is 100-500%, the elastic recovery rate is 70-99%, and the loading amount of the functional drug is 1-100 mg/cm³(ii) a The tensile strength of the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 1-10 MPa, and the elongation at break is 50-200%.

The invention also provides a method for preparing the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing, which comprises the steps of firstly carrying out electrostatic spinning on a precursor spinning solution I consisting of a synthetic polymer solution, an alcohol-soluble hydrophobic agent, an environment-friendly cross-linking agent and a functional drug to prepare a hydrophobic fiber membrane, then carrying out electrostatic spinning on a precursor spinning solution II consisting of a natural polymer solution, a catechol-based molecular solution and anhydrous ferric trichloride powder and receiving the electrostatic spinning solution on the hydrophobic fiber membrane to prepare a composite fiber membrane, and finally carrying out post-treatment on the composite fiber membrane to trigger a chemical cross-linking reaction between the synthetic polymer matrix and the environment-friendly cross-linking agent and a chemical cross-linking reaction between the natural polymer matrix and the catechol-based molecule to prepare the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing.

As a preferred technical scheme:

the method comprises the following specific preparation steps:

(1) preparing a synthetic polymer solution by adopting an environment-friendly solvent system, adding a corresponding alcohol-soluble hydrophobic agent, an environment-friendly cross-linking agent and a functional drug, and uniformly stirring to prepare a uniform and stable precursor spinning solution I;

(2) placing the precursor spinning solution I prepared in the step (1) into an injector, spinning by adopting an electrostatic spinning device, and receiving by a receiving base material to prepare a hydrophobic fiber membrane with the thickness of 0.1-0.3 mu m;

(3) dissolving natural polymer in deionized water, and stirring under certain conditions until the natural polymer is completely dissolved;

(4) dissolving catechol-based molecules as a cross-linking agent in deionized water, uniformly stirring at room temperature (25 ℃), adjusting the pH value of the solution to 9-11, and facilitating subsequent reaction of the catechol-based molecules and Fe when the pH value of the solution is in the range³⁺Bonding;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in a solvent, adding anhydrous ferric trichloride powder, and uniformly stirring to prepare a uniform and stable precursor spinning solution II;

(6) placing the precursor spinning solution II prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving the obtained hydrophilic fiber membrane on the hydrophobic fiber membrane in the step (3) to prepare a composite fiber membrane with the thickness of 0.2-0.6 mu m;

(7) carrying out post-treatment on the composite fiber membrane prepared in the step (6) to initiate a chemical crosslinking reaction between the synthetic polymer matrix and the environment-friendly crosslinking agent and a chemical crosslinking reaction between the natural polymer matrix and catechol-based molecules to obtain the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing;

the carboxyl end groups on the synthetic polymer molecular chains in the hydrophobic fiber membrane are initiated to perform condensation reaction with the amino groups carried by the environment-friendly cross-linking agent through post-treatment to form a covalent cross-linked network, so that the water resistance and the structural stability of the fiber membrane are enhanced; can promote natural high-grade separation by post-treatmentCatechol-based molecules (dopamine, tannic acid and tea polyphenol) with good biocompatibility and transition metal ion Fe³⁺Multiple bonding actions (covalent bonds, coordination bonds and hydrogen bonds) are generated, wherein the coordination bonds and the hydrogen bonds are reversible, so that self-repairing performance is endowed to the inner layer fibers, and the adhesion force between the double-layer fiber film layers is improved.

According to the method, the mass fraction of the synthetic polymer in the precursor spinning solution I is 5-20%, and the addition amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are 1-20 wt% and 1-5 wt% of the synthetic polymer respectively;

the mass fraction of the natural polymer in the precursor spinning solution II is 10-30%, and the addition amount of the catechol-based molecules is 1-10 wt% of the natural polymer.

The above substances are not used too much or too little, the performance of the obtained fiber membrane can not reach the expected index below the set range, and the spinning process can be influenced above the set range.

In the method, the environment-friendly solvent in the step (1) is water, absolute ethyl alcohol, propyl alcohol, ethylene glycol, propylene glycol or isopropyl alcohol;

the solvent in the step (5) is glacial acetic acid, and as the nanofiber membrane prepared by the method is mainly used for skin dressing, a nontoxic and environment-friendly solvent system is required to prevent the solvent remaining on the dressing from causing secondary damage to the wound surface.

In the method, the stirring under certain conditions in the step (3) until the solution is completely dissolved is stirring in a water bath at 30 ℃ for 30min, and then heating to 50 ℃ and continuing stirring for 30 min; or stirring at normal temperature until the natural polymer (solute) is dissolved;

in the step (4), the pH value is adjusted by adding 1mol/L NaOH solution;

the stirring in the step (5) is carried out in a water bath at normal temperature or 50 ℃.

In the method as described above, the receiving substrate used in the electrospinning in the step (2) is glossy paper, non-woven fabric or aluminum foil; the electrostatic spinning process parameters in the step (2) and the step (6) are as follows: the spinning voltage is 10-30 kV, the receiving distance is 5-30 cm, the filling speed is 0.5-10 mL/h, the temperature is 10-40 ℃, and the relative humidity is 5-100%.

The method as described above, wherein the post-treatment is a heat treatment;

the heat treatment adopts a vacuum oven, the treatment time is 10-120 min, the treatment temperature is 30-200 ℃, and the heat treatment is carried out for 10-120 min at room temperature.

Has the advantages that:

(1) the preparation method of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is simple and feasible and low in cost;

(2) the outer layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is a waterproof breathable high-elastic layer, so that the waterproof breathable high-elastic membrane has excellent resilience to ensure that the dressing can be attached to a wound joint and has good comfort, the invasion of moisture, bacteria and the like can be prevented, the wound seepage liquid is ensured to be conducted to the outside in a water vapor mode, parameters such as fiber pore diameter, porosity and the like can be regulated and controlled according to the type of a wound surface, the water pressure resistance and the water vapor permeability of the dressing can be regulated, and the healing promoting performance of the dressing is effectively improved;

(3) the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is a hydrophilic self-repairing layer, the natural polymer nanofiber prepared by the electrostatic spinning technology has high porosity, large length-diameter ratio and large specific surface area, is highly fitted with an extracellular matrix in size and structure, is favorable for adhesion, proliferation and tissue regeneration of cells, promotes transmission of nutrient substances and discharge of metabolites, and can effectively reduce scar generation; catechol-based molecules (dopamine, tannic acid and tea polyphenol) with good biocompatibility and natural polymer, and transition metal ion Fe³⁺Multiple bonding effects (covalent bond, coordination bond and hydrogen bond) are generated, self-repairing property is given to the inner layer fiber film, interlayer bonding force of the double-layer fiber film is improved, so that the reduction of the adhesion between the dressing and the skin caused by the breakage of the fibers due to external force is avoided, and the conditions of seepage absorption, nutrient substance transmission, wound healing and the like are delayed;

(4) the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing, which is prepared by the invention, integrates high elasticity, waterproof breathable performance and self-repairing performance, is suitable for wounds at skin joints, and when the dressing is subjected to external force, the inner layer fiber part is broken to realize rapid self-repairing so as to ensure the adhesiveness and long-term use of the dressing; can guarantee the laminating and the travelling comfort of the surface of a wound when promoting the healing ability of dressing.

Drawings

FIG. 1 is a schematic structural diagram of a waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for a skin dressing of the invention;

FIG. 2 is a stress-strain graph of the polyurethane nanofiber membrane of example 1;

FIG. 3 is an SEM image of a polyurethane nanofiber membrane in example 1;

fig. 4 is an SEM image of the gelatin nanofiber fiber membrane in example 2.

Detailed Description

The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Example 1

A preparation method of a waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for skin dressing comprises the following steps:

(1) preparing a waterborne polyurethane solution by using absolute ethyl alcohol, adding an alcohol-soluble hydrophobic agent (polymethylhydrosiloxane emulsion), an environment-friendly cross-linking agent (epoxy silane cross-linking agent) and a functional drug (diclofenac sodium), and uniformly stirring to prepare a precursor spinning solution I; the mass fraction of the waterborne polyurethane in the precursor spinning solution I is 5%, and the addition amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are respectively 10 wt% and 2 wt% of the waterborne polyurethane;

(2) putting the precursor spinning solution I prepared in the step (1) into an injector, spinning by adopting an electrostatic spinning device, and receiving by a receiving substrate (glossy paper) to prepare a hydrophobic fiber film with the thickness of 0.1 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 30kV, the receiving distance is 15cm, the perfusion speed is 2mL/h, the temperature is 25 ℃, and the relative humidity is 45 percent;

(3) dissolving chitosan in deionized water, and continuously stirring until the chitosan is completely dissolved;

(4) dissolving dopamine in deionized water, and adjusting the pH value of the solution to 9 by adding 1mol/L NaOH solution;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in a 30 wt% glacial acetic acid aqueous solution, adding anhydrous ferric trichloride powder, and uniformly stirring to prepare a precursor spinning solution II; the mass fraction of chitosan in the precursor spinning solution II is 15%, and the addition amounts of dopamine and anhydrous ferric trichloride powder are respectively 10 wt% and 2 wt% of chitosan;

(6) putting the precursor spinning solution prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving on the hydrophobic fiber membrane in the step (2) to prepare a composite fiber membrane with the thickness of 0.2 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 20kV, the receiving distance is 15cm, the perfusion speed is 0.5mL/h, the temperature is 25 ℃, and the relative humidity is 45 percent;

(7) carrying out heat treatment on the composite fiber membrane prepared in the step (6) to trigger a chemical crosslinking reaction between the waterborne polyurethane matrix and the epoxy silane crosslinking agent; carrying out heat treatment to initiate a chemical crosslinking reaction between the chitosan matrix and dopamine to prepare the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing; wherein the heat treatment adopts a vacuum oven, the treatment time is 30min, the treatment temperature is 60 ℃, and the room temperature is kept for 30 min; stress-strain curves and SEM images of the prepared polyurethane nanofiber membrane are shown in fig. 2 and 3, respectively;

as shown in figure 1, the diameter of the finally prepared waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 100-1500 nm, the length-diameter ratio of the fibers is 100-5000, the pore diameter is 0.2-1.8 mu m, and the porosity is 45%; the outer layer is a waterproof breathable high-elastic layer, and the inner layer is a hydrophilic self-repairing layer; the waterproof breathable high-elastic layer consists of a water-based polyurethane fiber matrix, polymethyl hydrogen siloxane emulsion, an epoxy silane cross-linking agent and diclofenac sodium,the polymethyl hydrogen siloxane emulsion, the epoxy silane cross-linking agent and the diclofenac sodium are uniformly distributed on the aqueous polyurethane fiber substrate, and the epoxy silane cross-linking agent and the aqueous polyurethane fiber form a cross-linking network; the hydrophilic self-repairing layer is composed of a chitosan fiber matrix, dopamine and Fe³⁺Composition of, among others, dopamine and Fe³⁺Uniformly distributed on the chitosan fiber matrix, and forms a dynamic reversible cross-linked network with the chitosan fiber; the performance indexes of the outer layer and the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 1; the performance indexes of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 2.

Example 2

(1) preparing an aqueous acrylic resin solution by using isopropanol, adding an alcohol-soluble hydrophobic agent (polymethyl hydrogen siloxane emulsion), an environment-friendly cross-linking agent (organosilane cross-linking agent) and a functional drug (warfarin), and uniformly stirring to prepare a precursor spinning solution I; the mass fraction of the water-based acrylic resin in the precursor spinning solution I is 12%, and the addition amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are respectively 5 wt% and 1 wt% of the water-based acrylic resin;

(2) putting the precursor spinning solution I prepared in the step (1) into an injector, spinning by adopting an electrostatic spinning device, and receiving by a receiving substrate (aluminum foil) to prepare a hydrophobic fiber membrane with the thickness of 0.1 mu m; wherein the electrostatic spinning process parameters are as follows: spinning voltage is 25kV, receiving distance is 13cm, filling speed is 1mL/h, temperature is 22 ℃, and relative humidity is 47%;

(3) dissolving gelatin in deionized water, stirring in 30 deg.C water bath for 30min, heating to 50 deg.C, and stirring for 30min to dissolve completely;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in a 30 wt% glacial acetic acid aqueous solution, adding anhydrous ferric trichloride powder, and uniformly stirring the mixture in a water bath at 50 ℃ to prepare a precursor spinning solution II; the mass fraction of gelatin in the precursor spinning solution II is 10%, and the addition amounts of dopamine and anhydrous ferric trichloride powder are 5 wt% and 1 wt% of the gelatin respectively;

(6) placing the precursor spinning solution II prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving on the hydrophobic fiber membrane in the step (2) to prepare a composite fiber membrane with the thickness of 0.3 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 20kV, the receiving distance is 13cm, the perfusion speed is 0.5mL/h, the temperature is 22 ℃, and the relative humidity is 47 percent; the SEM image of the gelatin nanofiber membrane is shown in fig. 4;

(7) carrying out heat treatment on the composite fiber membrane prepared in the step (6) to initiate a chemical crosslinking reaction between the aqueous acrylic resin matrix and the organosilane crosslinking agent; carrying out heat treatment to cause a chemical crosslinking reaction between the gelatin matrix and dopamine to prepare the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing; wherein the heat treatment adopts a vacuum oven, the treatment time is 20min, the treatment temperature is 50 ℃, and the room temperature is kept for 10 min.

The diameter of the fiber of the finally prepared waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 300-1000 nm, the length-diameter ratio of the fiber is 100-5000, the pore diameter is 0.2-1.7 mu m, and the porosity is 42%; the outer layer is a waterproof breathable high-elastic layer, and the inner layer is a hydrophilic self-repairing layer; the waterproof breathable high-elastic layer consists of a water-based acrylic fiber matrix, polymethyl hydrogen siloxane emulsion, an organosilane crosslinking agent and warfarin, wherein the polymethyl hydrogen siloxane emulsion, the organosilane crosslinking agent and the warfarin are uniformly distributed on the water-based acrylic fiber matrix, and the silane crosslinking agent and the water-based acrylic fiber form a crosslinking network; the hydrophilic self-repairing layer is made of a gelatin fiber matrix, dopamine and Fe³⁺Composition of, among others, dopamine and Fe³⁺Uniformly distributed on the gelatin fiber matrix and forms a dynamic reversible crosslinking network with the gelatin fiber; the performance indexes of the outer layer and the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 1; the performance indexes of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 2.

Example 3

(1) preparing a polyvinylpyrrolidone solution by adopting absolute ethyl alcohol, adding an alcohol-soluble hydrophobic agent (polydimethylsiloxane emulsion), an environment-friendly cross-linking agent (blocked isocyanate cross-linking agent) and a functional drug (aspirin), and uniformly stirring to prepare a precursor spinning solution I; the mass fraction of polyvinylpyrrolidone in the precursor spinning solution I is 10%, and the addition amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are respectively 10 wt% and 2 wt% of the polyvinylpyrrolidone;

(2) putting the precursor spinning solution I prepared in the step (1) into an injector, spinning by adopting an electrostatic spinning device, and receiving by a receiving substrate (glossy paper) to prepare a hydrophobic fiber film with the thickness of 0.3 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 30kV, the receiving distance is 15cm, the perfusion speed is 3mL/h, the temperature is 22 ℃, and the relative humidity is 45 percent;

(4) dissolving tannic acid in deionized water, and adjusting the pH value of the solution to 9 by adding 1mol/L NaOH solution;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in a 20 wt% glacial acetic acid aqueous solution, adding anhydrous ferric trichloride powder, and uniformly stirring the mixture in a water bath at 50 ℃ to prepare a precursor spinning solution II; the mass fraction of gelatin in the precursor spinning solution II is 15%, and the adding amount of tannic acid and anhydrous ferric trichloride powder is 10 wt% and 1 wt% of the gelatin respectively;

(6) placing the precursor spinning solution II prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving on the hydrophobic fiber membrane in the step (2) to prepare a composite fiber membrane with the thickness of 0.6 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 20kV, the receiving distance is 10cm, the perfusion speed is 0.5mL/h, the temperature is 22 ℃, and the relative humidity is 45 percent;

(7) carrying out heat treatment on the composite fiber membrane prepared in the step (6) to initiate a chemical crosslinking reaction between a polyvinylpyrrolidone matrix and a closed isocyanate crosslinking agent; carrying out heat treatment to cause a chemical crosslinking reaction between the gelatin matrix and the tannic acid to prepare the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing; wherein the heat treatment adopts a vacuum oven, the treatment time is 30min, the treatment temperature is 60 ℃, and the room temperature is 60 min.

The fiber diameter of the finally prepared waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 500-2000 nm, the length-diameter ratio of the fibers is 50-5000, the pore diameter is 0.2-1.5 mu m, and the porosity is 39%; the outer layer is a waterproof breathable high-elastic layer, and the inner layer is a hydrophilic self-repairing layer; the waterproof breathable high-elastic layer consists of a polyvinylpyrrolidone fiber substrate, polydimethylsiloxane emulsion, a closed isocyanate crosslinking agent and aspirin, wherein the polydimethylsiloxane emulsion, the closed isocyanate crosslinking agent and the aspirin are uniformly distributed on the polyvinylpyrrolidone fiber substrate, and the closed isocyanate crosslinking agent and the polyvinylpyrrolidone fiber form a crosslinking network; the hydrophilic self-repairing layer is made of a gelatin fiber matrix, tannic acid and Fe³⁺Composition of, wherein, tannic acid and Fe³⁺Uniformly distributed on the gelatin fiber matrix and forms a dynamic reversible crosslinking network with the gelatin fiber; the performance indexes of the outer layer and the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 1; the performance indexes of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 2.

Example 4

(1) preparing a polyvinyl butyral solution by using propylene glycol, adding an alcohol-soluble hydrophobic agent (polymethylhydrosiloxane emulsion), an environment-friendly cross-linking agent (polycarbodiimide) and a functional drug (curcumin), and uniformly stirring to prepare a precursor spinning solution I; the mass fraction of polyvinyl butyral in the precursor spinning solution I is 15%, and the addition amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are 12 wt% and 3 wt% of the polyvinyl butyral respectively;

(2) putting the precursor spinning solution I prepared in the step (1) into an injector, spinning by adopting an electrostatic spinning device, and receiving by a receiving substrate (glossy paper) to prepare a hydrophobic fiber film with the thickness of 0.3 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 30kV, the receiving distance is 18cm, the perfusion speed is 2mL/h, the temperature is 25 ℃, and the relative humidity is 50 percent;

(4) dissolving tannic acid in deionized water, and adjusting the pH value of the solution to 11 by adding 1mol/L NaOH solution;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in a 20 wt% glacial acetic acid aqueous solution, adding anhydrous ferric trichloride powder, and uniformly stirring to prepare a precursor spinning solution II; the mass fraction of chitosan in the precursor spinning solution II is 12%, and the adding amounts of tannic acid and anhydrous ferric trichloride powder are respectively 10 wt% and 2.5 wt% of chitosan;

(6) placing the precursor spinning solution II prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving on the hydrophobic fiber membrane in the step (2) to prepare a composite fiber membrane with the thickness of 0.6 mu m; wherein the electrostatic spinning process parameters are as follows: spinning voltage is 8kV, receiving distance is 15cm, filling speed is 0.5mL/h, temperature is 20 ℃, and relative humidity is 40%;

(7) carrying out heat treatment on the composite fiber membrane prepared in the step (6) to initiate a chemical crosslinking reaction between the polyvinyl butyral matrix and the polycarbodiimide; carrying out heat treatment to initiate a chemical crosslinking reaction between the chitosan matrix and the tannic acid; wherein the heat treatment adopts a vacuum oven, the treatment time is 30min, the treatment temperature is 30 ℃, and the room temperature is kept for 30 min;

the fiber diameter of the finally prepared waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 500-2000 nm, the length-diameter ratio of the fibers is 50-5000, the pore diameter is 0.3-1.6 mu m, and the porosity is 40%; the outer layer is a waterproof breathable high-elastic layer, and the inner layer is a hydrophilic self-repairing layer; the waterproof breathable high-elastic layer is composed of a polyvinyl butyral fiber substrate and polyvinylThe polyvinyl butyral fiber comprises methyl hydrogen siloxane emulsion, polycarbodiimide and curcumin, wherein the methyl hydrogen siloxane emulsion, the polycarbodiimide and the curcumin are uniformly distributed on a polyvinyl butyral fiber substrate, and the polycarbodiimide and the polyvinyl butyral fiber form a cross-linked network; the hydrophilic self-repairing layer is composed of a chitosan fiber matrix, tannic acid and Fe³⁺Composition of, wherein, tannic acid and Fe³⁺Uniformly distributed on the chitosan fiber matrix, and forms a dynamic reversible cross-linked network with the chitosan fiber; the performance indexes of the outer layer and the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 1; the performance indexes of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 2.

Example 5

(1) preparing an aqueous acrylic resin solution by using absolute ethyl alcohol, adding an alcohol-soluble hydrophobic agent (a mixture of polymethylhydrosiloxane emulsion and polydimethylsiloxane emulsion (the mass ratio is 1: 1)), an environment-friendly cross-linking agent (epoxy silane cross-linking agent) and a functional drug (curcumin), and uniformly stirring to prepare a precursor spinning solution I; the mass fraction of the water-based acrylic resin in the precursor spinning solution I is 10%, and the addition amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are respectively 10 wt% and 2.5 wt% of the water-based acrylic resin;

(2) putting the precursor spinning solution I prepared in the step (1) into an injector, spinning by adopting an electrostatic spinning device, and receiving by a receiving substrate (aluminum foil) to prepare a hydrophobic fiber membrane with the thickness of 0.2 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 30kV, the receiving distance is 13cm, the perfusion speed is 2mL/h, the temperature is 21 ℃, and the relative humidity is 51 percent;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in a 30 wt% glacial acetic acid aqueous solution, adding anhydrous ferric trichloride powder, and uniformly stirring the mixture in a water bath at 50 ℃ to prepare a precursor spinning solution II; the mass fraction of gelatin in the precursor spinning solution II is 16%, and the adding amount of tannic acid and anhydrous ferric trichloride powder is 8 wt% and 2 wt% of gelatin respectively;

(6) putting the precursor spinning solution II prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving on the hydrophobic fiber membrane in the step (2) to prepare a composite fiber membrane with the thickness of 0.4 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 18kV, the receiving distance is 15cm, the perfusion speed is 1mL/h, the temperature is 21 ℃, and the relative humidity is 51 percent;

(7) carrying out heat treatment on the composite fiber membrane prepared in the step (6) to initiate a chemical crosslinking reaction between the aqueous acrylic resin matrix and the epoxy silane crosslinking agent; carrying out heat treatment to cause a chemical crosslinking reaction between the gelatin matrix and the tannic acid to prepare the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing; wherein the heat treatment adopts a vacuum oven, the treatment time is 60min, the treatment temperature is 30 ℃, and the room temperature is kept for 60 min.

The diameter of the finally prepared waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 200-2000 nm, the length-diameter ratio of the fibers is 50-6000, the pore diameter is 0.2-1.4 mu m, and the porosity is 37%; the outer layer is a waterproof breathable high-elastic layer, and the inner layer is a hydrophilic self-repairing layer; the waterproof breathable high-elastic layer consists of a water-based acrylic fiber matrix, polymethyl hydrogen siloxane emulsion, polydimethylsiloxane emulsion, epoxy silane cross-linking agent and curcumin, wherein the polymethyl hydrogen siloxane emulsion, the polydimethylsiloxane emulsion, the epoxy silane cross-linking agent and the curcumin are uniformly distributed on the water-based acrylic fiber matrix, and the epoxy silane cross-linking agent and the water-based acrylic fiber form a cross-linking network; the hydrophilic self-repairing layer is made of a gelatin fiber matrix, tannic acid and Fe³⁺Composition of, wherein, tannic acid and Fe³⁺Uniformly distributed on the gelatin fiber matrix and forms a dynamic reversible crosslinking network with the gelatin fiber; waterproof breathable high-elastic self-repairing double-layer nanofiber for skin dressingThe performance indexes of the outer layer and the inner layer of the film are shown in table 1; the performance indexes of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 2.

Example 6

(1) preparing a polyvinylpyrrolidone solution by using propylene glycol, adding an alcohol-soluble hydrophobic agent (hydrogen-containing silicone oil), an environment-friendly cross-linking agent (organosilane cross-linking agent) and a functional drug (curcumin), and uniformly stirring to prepare a precursor spinning solution I; the mass fraction of the precursor spinning solution I is 15%, and the addition amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are 12 wt% and 3 wt%, respectively;

(2) putting the precursor spinning solution I prepared in the step (1) into an injector, spinning by adopting an electrostatic spinning device, and receiving by a receiving substrate (non-woven fabric) to prepare a hydrophobic fiber membrane with the thickness of 0.2 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 28kV, the receiving distance is 18cm, the perfusion speed is 3mL/h, the temperature is 24 ℃, and the relative humidity is 43 percent;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in a 30 wt% glacial acetic acid aqueous solution, adding anhydrous ferric trichloride powder, and uniformly stirring to prepare a precursor spinning solution II; the mass fraction of chitosan in the precursor spinning solution II is 18%, and the addition amounts of dopamine and anhydrous ferric trichloride powder are respectively 5 wt% and 2 wt% of chitosan;

(6) placing the precursor spinning solution II prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving on the hydrophobic fiber membrane in the step (2) to prepare a composite fiber membrane with the thickness of 0.6 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 18kV, the receiving distance is 20cm, the perfusion speed is 0.5mL/h, the temperature is 24 ℃, and the relative humidity is 43 percent;

(7) carrying out heat treatment on the composite fiber membrane prepared in the step (6) to initiate a chemical crosslinking reaction between a polyvinylpyrrolidone matrix and an organosilane crosslinking agent; carrying out heat treatment to initiate a chemical crosslinking reaction between the chitosan matrix and dopamine to prepare the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing; wherein the heat treatment adopts a vacuum oven, the treatment time is 60min, the treatment temperature is 30 ℃, and the room temperature is kept for 60 min.

The diameter of the fiber of the finally prepared waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 100-1000 nm, the length-diameter ratio of the fiber is 100-5000, the pore diameter is 0.2-1.2 mu m, and the porosity is 49%; the outer layer is a waterproof breathable high-elastic layer, and the inner layer is a hydrophilic self-repairing layer; the waterproof breathable high-elastic layer consists of a polyvinylpyrrolidone fiber matrix, hydrogen-containing silicone oil, an organosilane crosslinking agent and curcumin, wherein the hydrogen-containing silicone oil, the organosilane crosslinking agent and the curcumin are uniformly distributed on the polyvinylpyrrolidone fiber matrix, and the organosilane crosslinking agent and the polyvinylpyrrolidone fiber form a crosslinking network; the hydrophilic self-repairing layer is composed of a chitosan fiber matrix, dopamine and Fe³⁺Composition of, among others, dopamine and Fe³⁺Uniformly distributed on the chitosan fiber matrix, and forms a dynamic reversible cross-linked network with the chitosan fiber; the performance indexes of the outer layer and the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 1; the performance indexes of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 2.

Example 7

(1) preparing a water-borne polyurethane solution by using isopropanol, adding an alcohol-soluble hydrophobic agent (hydrogen-containing silicone oil), an environment-friendly cross-linking agent (a closed isocyanate cross-linking agent) and a functional drug (warfarin), and uniformly stirring to obtain a precursor spinning solution I; the mass fraction of the waterborne polyurethane in the precursor spinning solution I is 8%, and the adding amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are respectively 10 wt% and 2.5 wt% of the waterborne polyurethane;

(2) putting the precursor spinning solution I prepared in the step (1) into an injector, spinning by adopting an electrostatic spinning device, and receiving by a receiving substrate (aluminum foil) to prepare a hydrophobic fiber membrane with the thickness of 0.2 mu m; wherein the electrostatic spinning process parameters are as follows: spinning voltage is 25kV, receiving distance is 20cm, filling speed is 3mL/h, temperature is 23 ℃, and relative humidity is 50%;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in 25 wt% of glacial acetic acid aqueous solution, adding anhydrous ferric trichloride powder, and uniformly stirring to prepare a precursor spinning solution II; the mass fraction of chitosan in the precursor spinning solution II is 15%, and the adding amount of tannic acid and anhydrous ferric trichloride powder is respectively 8 wt% and 1 wt% of chitosan;

(6) placing the precursor spinning solution II prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving on the hydrophobic fiber membrane in the step (2) to prepare a composite fiber membrane with the thickness of 0.6 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 20kV, the receiving distance is 20cm, the perfusion speed is 1mL/h, the temperature is 23 ℃, and the relative humidity is 50 percent;

(7) carrying out heat treatment on the composite fiber membrane prepared in the step (6) to trigger a chemical crosslinking reaction between the aqueous polyurethane matrix and the closed isocyanate crosslinking agent; carrying out heat treatment to initiate a chemical crosslinking reaction between the chitosan matrix and tannic acid to prepare the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing; wherein the heat treatment adopts a vacuum oven, the treatment time is 60min, the treatment temperature is 60 ℃, and the room temperature is kept for 60 min.

The fiber diameter of the finally prepared waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 500-800 nm, the length-diameter ratio of the fibers is 50-5000, the pore diameter is 0.4-1.6 mu m, and the porosity is 50%; the outer layer is a waterproof breathable high-elastic layer, and the inner layer is a hydrophilic self-repairing layer; the waterproof breathable high-elastic layer consists of a water-based polyurethane fiber substrate,The water-based polyurethane fiber comprises hydrogen-containing silicone oil, a closed isocyanate cross-linking agent and warfarin, wherein the hydrogen-containing silicone oil, the closed isocyanate cross-linking agent and the warfarin are uniformly distributed on a water-based polyurethane fiber matrix, and the closed isocyanate cross-linking agent and the water-based polyurethane fiber form a cross-linked network; the hydrophilic self-repairing layer is composed of a chitosan fiber matrix, tannic acid and Fe³⁺Composition of, wherein, tannic acid and Fe³⁺Uniformly distributed on the chitosan fiber matrix, and forms a dynamic reversible cross-linked network with the chitosan fiber; the performance indexes of the outer layer and the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 1; the performance indexes of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 2.

Example 8

(1) preparing a water-borne polyurethane solution by using absolute ethyl alcohol, adding an alcohol-soluble hydrophobic agent (polydimethylsiloxane emulsion), an environment-friendly cross-linking agent (polycarbodiimide) and a functional drug (diclofenac sodium), and uniformly stirring to prepare a precursor spinning solution I; the mass fraction of the waterborne polyurethane in the precursor spinning solution I is 5%, and the addition amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are respectively 8 wt% and 2 wt% of the waterborne polyurethane;

(2) putting the precursor spinning solution I prepared in the step (1) into an injector, spinning by adopting an electrostatic spinning device, and receiving by a receiving substrate (non-woven fabric) to prepare a hydrophobic fiber membrane with the thickness of 0.2 mu m; wherein the electrostatic spinning process parameters are as follows: spinning voltage is 25kV, receiving distance is 18cm, filling speed is 2mL/h, temperature is 23 ℃, and relative humidity is 60%;

(4) dissolving tea polyphenol in deionized water, and adjusting the pH value of the solution to 9 by adding 1mol/L NaOH solution;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in 25 wt% of glacial acetic acid water solution, adding anhydrous ferric trichloride powder, and uniformly stirring the mixture in a water bath at 50 ℃ to prepare a precursor spinning solution II; the mass fraction of gelatin in the precursor spinning solution II is 16%, and the addition amounts of tea polyphenol and anhydrous ferric trichloride powder are respectively 4 wt% and 1 wt% of gelatin;

(6) placing the precursor spinning solution II prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving on the hydrophobic fiber membrane in the step (2) to prepare a composite fiber membrane with the thickness of 0.6 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 20kV, the receiving distance is 18cm, the perfusion speed is 1mL/h, the temperature is 23 ℃, and the relative humidity is 75 percent;

(7) carrying out heat treatment on the composite fiber membrane prepared in the step (6) to trigger a chemical crosslinking reaction between the waterborne polyurethane matrix and polycarbodiimide; carrying out heat treatment to cause a chemical crosslinking reaction between the gelatin matrix and the tea polyphenol to prepare the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing; wherein the heat treatment adopts a vacuum oven, the treatment time is 90min, the treatment temperature is 40 ℃, and the room temperature is kept for 60 min.

The fiber diameter of the finally prepared waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 500-2000 nm, the length-diameter ratio of the fibers is 50-3000, the pore diameter is 0.4-1.4 mu m, and the porosity is 41%; the outer layer is a waterproof breathable high-elastic layer, and the inner layer is a hydrophilic self-repairing layer; the waterproof breathable high-elasticity layer is composed of an aqueous polyurethane fiber substrate, polydimethylsiloxane emulsion, polycarbodiimide and diclofenac sodium, wherein the polydimethylsiloxane emulsion, the polycarbodiimide and the diclofenac sodium are uniformly distributed on the aqueous polyurethane fiber substrate, and the polycarbodiimide and the aqueous polyurethane fiber form a cross-linked network; the hydrophilic self-repairing layer is made of gelatin fiber matrix, tea polyphenol and Fe³⁺Comprises, wherein, tea polyphenol and Fe³⁺Uniformly distributed on the gelatin fiber matrix and forms a dynamic reversible crosslinking network with the gelatin fiber; the performance indexes of the outer layer and the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 1; the performance indexes of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in the table2, respectively.

Example 9

(1) preparing a water-borne polyurethane solution by using absolute ethyl alcohol, adding an alcohol-soluble hydrophobic agent (hydrogen-containing silicone oil), an environment-friendly cross-linking agent (polycarbodiimide) and a functional drug (ferulic acid), and uniformly stirring to prepare a precursor spinning solution I; the mass fraction of the waterborne polyurethane in the precursor spinning solution I is 10%, and the adding amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are respectively 12 wt% and 2 wt% of the waterborne polyurethane;

(2) putting the precursor spinning solution I prepared in the step (1) into an injector, spinning by adopting an electrostatic spinning device, and receiving by a receiving substrate (glossy paper) to prepare a hydrophobic fiber film with the thickness of 0.2 mu m; wherein the electrostatic spinning process parameters are as follows: spinning voltage is 25kV, receiving distance is 20cm, filling speed is 3mL/h, temperature is 27 ℃, and relative humidity is 70%;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in a 20 wt% glacial acetic acid aqueous solution, adding anhydrous ferric trichloride powder, and uniformly stirring the mixture in a water bath at 50 ℃ to prepare a precursor spinning solution II; the mass fraction of gelatin in the precursor spinning solution II is 12%, and the addition amounts of tea polyphenol and anhydrous ferric trichloride powder are respectively 6 wt% and 1 wt% of the gelatin;

(6) placing the precursor spinning solution II prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving on the hydrophobic fiber membrane in the step (2) to prepare a composite fiber membrane with the thickness of 0.6 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 18kV, the receiving distance is 20cm, the perfusion speed is 0.5mL/h, the temperature is 27 ℃, and the relative humidity is 70 percent;

(7) carrying out heat treatment on the composite fiber membrane prepared in the step (6) to trigger a chemical crosslinking reaction between the waterborne polyurethane matrix and polycarbodiimide; carrying out heat treatment to cause a chemical crosslinking reaction between the gelatin matrix and the tea polyphenol to prepare the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing; wherein the heat treatment adopts a vacuum oven, the treatment time is 100min, the treatment temperature is 30 ℃, and the room temperature is kept for 30 min.

The fiber diameter of the finally prepared waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 300-1500 nm, the length-diameter ratio of the fibers is 50-4000, the pore diameter is 0.3-1.2 mu m, and the porosity is 31%; the outer layer is a waterproof breathable high-elastic layer, and the inner layer is a hydrophilic self-repairing layer; the waterproof breathable high-elastic layer consists of an aqueous polyurethane fiber substrate, hydrogen-containing silicone oil, polycarbodiimide and ferulic acid, wherein the hydrogen-containing silicone oil, the polycarbodiimide and the ferulic acid are uniformly distributed on the aqueous polyurethane fiber substrate, and the polycarbodiimide and the aqueous polyurethane fiber form a cross-linked network; the hydrophilic self-repairing layer is made of gelatin fiber matrix, tea polyphenol and Fe³⁺Comprises tea polyphenols and Fe³⁺Uniformly distributed on the gelatin fiber matrix and forms a dynamic reversible crosslinking network with the gelatin fiber; the performance indexes of the outer layer and the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 1; the performance indexes of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 2.

Example 10

(1) preparing a water-borne polyurethane solution by using absolute ethyl alcohol, adding an alcohol-soluble hydrophobic agent (polymethylhydrosiloxane emulsion), an environment-friendly cross-linking agent (polycarbodiimide) and a functional drug (curcumin), and uniformly stirring to prepare a precursor spinning solution I; the mass fraction of the waterborne polyurethane in the precursor spinning solution I is 15%, and the adding amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are respectively 12 wt% and 2 wt% of the waterborne polyurethane;

(2) putting the precursor spinning solution I prepared in the step (1) into an injector, spinning by adopting an electrostatic spinning device, and receiving by a receiving substrate (non-woven fabric) to prepare a hydrophobic fiber membrane with the thickness of 0.2 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 30kV, the receiving distance is 15cm, the perfusion speed is 3mL/h, the temperature is 26 ℃, and the relative humidity is 80 percent;

(4) dissolving dopamine in deionized water, and adjusting the pH value of the solution to 11 by adding 1mol/L NaOH solution;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in a 30 wt% glacial acetic acid aqueous solution, adding anhydrous ferric trichloride powder, and uniformly stirring the mixture in a water bath at 50 ℃ to prepare a precursor spinning solution II; the mass fraction of gelatin in the precursor spinning solution II is 16%, and the addition amounts of dopamine and anhydrous ferric trichloride powder are respectively 8 wt% and 1 wt% of the gelatin;

(6) placing the precursor spinning solution II prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving on the hydrophobic fiber membrane in the step (2) to prepare a composite fiber membrane with the thickness of 0.6 mu m; wherein the electrostatic spinning process parameters are as follows: the spinning voltage is 20kV, the receiving distance is 15cm, the perfusion speed is 1mL/h, the temperature is 26 ℃, and the relative humidity is 80 percent;

(7) carrying out heat treatment on the composite fiber membrane prepared in the step (6) to trigger a chemical crosslinking reaction between the waterborne polyurethane matrix and polycarbodiimide; carrying out heat treatment to cause a chemical crosslinking reaction between the gelatin matrix and dopamine to prepare the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing; wherein the heat treatment adopts a vacuum oven, the treatment time is 120min, the treatment temperature is 30 ℃, and the room temperature is kept for 30 min.

The fiber diameter of the finally prepared waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 200-1800 nm, the length-diameter ratio of the fibers is 50-5000, the pore diameter is 0.3-1.5 mu m, and the porosity is 33%; the outer layer is a waterproof breathable high-elastic layer, and the inner layer is a hydrophilic self-repairing layer; the waterproof breathable high-elastic layer is composed of a water-based polyurethane fiber matrix, polymethyl hydrogen siloxane emulsion and polycarbodiimideThe paint consists of diimine and curcumin, wherein the polymethylhydrosiloxane emulsion, polycarbodiimide and curcumin are uniformly distributed on a water-based polyurethane fiber matrix, and the polycarbodiimide and the water-based polyurethane fiber form a cross-linked network; the hydrophilic self-repairing layer is made of a gelatin fiber matrix, dopamine and Fe³⁺Composition of, among others, dopamine and Fe³⁺Uniformly distributed on the gelatin fiber matrix and forms a dynamic reversible crosslinking network with the gelatin fiber; the performance indexes of the outer layer and the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 1; the performance indexes of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing are shown in table 2.

TABLE 1

TABLE 2

Claims

1. The utility model provides a skin dressing is with double-deck nanofiber membrane of waterproof ventilative high-elastic selfreparing which characterized by: the outer layer is a waterproof breathable high-elastic layer, and the inner layer is a hydrophilic self-repairing layer;

the waterproof breathable high-elastic layer consists of a synthetic polymer fiber matrix, an alcohol-soluble hydrophobic agent, an environment-friendly cross-linking agent and a functional drug; wherein, the alcohol-soluble hydrophobic agent, the environment-friendly cross-linking agent and the functional drug are uniformly distributed on the synthetic polymer fiber matrix, and the environment-friendly cross-linking agent and the synthetic polymer fiber form a cross-linked network;

the hydrophilic self-repairing layer is composed of a natural polymer fiber matrix, catechol-based molecules and Fe³⁺Composition is carried out; wherein the catechol-based molecule and Fe³⁺The polymer fiber is uniformly distributed on a natural polymer fiber matrix and forms a dynamic reversible crosslinking network with the natural polymer fiber;

the catechol-based molecules are dopamine, tannic acid or tea polyphenol;

multiple bonding networks are constructed between the outer layer and the inner layer, and the multiple bonding networks are formed by covalent bonds and hydrogen bonds between synthetic polymer nano-fibers and catechol-based molecules, natural polymer nano-fibers and Fe³⁺Coordination between the natural polymer nano-fiber and the catechol-based molecule, covalent bond and hydrogen bond between the natural polymer nano-fiber and the catechol-based molecule, and the catechol-based molecule and Fe³⁺Constructing metal coordination between the two components;

the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for skin dressing has the water pressure resistance of 5-50 kPa and the breathability of 5-15 kg/m²D, the tensile strength is 5-15 MPa, the elongation at break is 50-400%, the elastic modulus is 5-15 MPa, and the elastic recovery rate is 60-99%; after the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is subjected to self-repairing, the tensile strength and the elongation at break of the membrane are 50-90% of the initial tensile strength and elongation at break of the membrane.

2. The waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing as claimed in claim 1, wherein the synthetic polymer is waterborne polyurethane, waterborne acrylic resin, polyvinylpyrrolidone or polyvinyl butyral; the alcohol-soluble hydrophobic agent is more than one of hydrogen-containing silicone oil, polymethylhydrosiloxane emulsion and polydimethylsiloxane emulsion; the environment-friendly cross-linking agent is an epoxy silane cross-linking agent, an organosilane cross-linking agent, a closed isocyanate cross-linking agent or polycarbodiimide; the functional medicine is curcumin, diclofenac sodium, warfarin, ferulic acid or aspirin; the natural polymer is gelatin or chitosan.

3. The waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing as claimed in claim 1, wherein the diameter of the fibers of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 100-2000 nm, the length-diameter ratio of the fibers is 10-10000, the pore diameter is 0.2-2.0 μm, and the porosity is 20-80%;

outer water pressure resistance of waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for skin dressing is 10 to100kPa, and air permeability of 5 to 15kg/m²The tensile strength is 5-20 MPa, the elongation at break is 100-500%, the elastic recovery rate is 70-99%, and the loading amount of the functional drug is 1-100 mg/cm³(ii) a The tensile strength of the inner layer of the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing is 1-10 MPa, and the elongation at break is 50-200%.

4. The method for preparing the waterproof breathable high-elastic self-repairing double-layer nanofiber membrane for the skin dressing as claimed in any one of claims 1 to 3, is characterized in that: firstly, performing electrostatic spinning on a precursor spinning solution I consisting of a synthetic polymer solution, an alcohol-soluble hydrophobic agent, an environment-friendly cross-linking agent and a functional drug to prepare a hydrophobic fiber membrane, then performing electrostatic spinning on a precursor spinning solution II consisting of a natural polymer solution, a catechol-based molecule solution and anhydrous ferric trichloride powder and receiving the electrostatic spinning solution on the hydrophobic fiber membrane to prepare a composite fiber membrane, and finally performing post-treatment on the composite fiber membrane to initiate a chemical cross-linking reaction between the synthetic polymer matrix and the environment-friendly cross-linking agent and a chemical cross-linking reaction between the natural polymer matrix and the catechol-based molecule to prepare the waterproof breathable high-elasticity self-repairing double-layer nanofiber membrane for the skin dressing.

5. The method according to claim 4, characterized by comprising the following steps:

(1) preparing a synthetic polymer solution by adopting an environment-friendly solvent, adding an alcohol-soluble hydrophobic agent, an environment-friendly cross-linking agent and a functional drug, and uniformly stirring to prepare a precursor spinning solution I;

(4) dissolving catechol-based molecules in deionized water, and adjusting the pH value of the solution to 9-11;

(5) mixing the solutions prepared in the step (3) and the step (4), dissolving the mixed solutions in a solvent, adding anhydrous ferric trichloride powder, and uniformly stirring to prepare a precursor spinning solution II;

(6) placing the precursor spinning solution II prepared in the step (5) into an injector, spinning by adopting an electrostatic spinning device, and receiving the precursor spinning solution II on the hydrophobic fiber membrane obtained in the step (2) to prepare a composite fiber membrane with the thickness of 0.2-0.6 mu m;

(7) and (4) carrying out post-treatment on the composite fiber membrane prepared in the step (6) to initiate a chemical crosslinking reaction between the synthetic polymer matrix and the environment-friendly crosslinking agent, and a chemical crosslinking reaction between the natural polymer matrix and catechol-based molecules, so as to prepare the waterproof, breathable, high-elastic and self-repairing double-layer nanofiber membrane for the skin dressing.

6. The method according to claim 4 or 5, characterized in that the mass fraction of the synthetic polymer in the precursor spinning solution I is 5-20%, and the addition amounts of the alcohol-soluble hydrophobic agent and the environment-friendly cross-linking agent are 1-20 wt% and 1-5 wt% of the synthetic polymer respectively;

the mass fraction of the natural polymer in the precursor spinning solution II is 10-30%, and the addition amounts of the catechol-based molecule and the anhydrous ferric trichloride powder are 1-10 wt% and 0.5-5 wt% of the natural polymer respectively.

7. The method according to claim 5, wherein the environmentally friendly solvent in step (1) is absolute ethanol, propylene glycol or isopropanol;

the solvent in the step (5) is glacial acetic acid.

8. The method as claimed in claim 5, wherein the stirring under certain conditions in the step (3) to complete dissolution is stirring in a water bath at 30 ℃ for 30min, and then heating to 50 ℃ to continue stirring for 30 min; or stirring at normal temperature until the natural polymer is dissolved;

in the step (4), the pH value is adjusted by adding 1mol/L NaOH solution;

9. The method according to claim 5, wherein the receiving substrate used for the electrospinning in the step (2) is glossy paper, nonwoven fabric or aluminum foil; the electrostatic spinning process parameters in the step (2) and the step (6) are as follows: the spinning voltage is 10-30 kV, the receiving distance is 5-30 cm, the filling speed is 0.5-10 mL/h, the temperature is 10-40 ℃, and the relative humidity is 5-100%.

10. The method according to claim 4 or 5, wherein the post-treatment is a heat treatment;