Composite fiber membrane, method for producing the same, and use thereof

Abstract

This invention relates to the field of medical dressings, and discloses a composite fiber membrane, its preparation method, and its applications. The composite fiber membrane includes a pH-responsive fiber membrane, a hydrophobic fiber membrane distributed on one side of the pH-responsive fiber membrane, and a hydrophilic fiber membrane distributed on the other side of the pH-responsive fiber membrane. The pH-responsive fiber membrane comprises polyethylene oxide, chitosan, and alizarin dye. This composite fiber membrane exhibits good antibacterial effects and unidirectional moisture-wicking function, and can also change color under different pH conditions, showing great promise for application in the field of medical dressings.

Description

Technical Field

[0001] This invention relates to the field of medical dressings, specifically to a composite fiber membrane, its preparation method, and its application. Background Technology

[0002] Burns and scalds are common occurrences in daily life, causing wounds of varying depths that are highly susceptible to infection and complications. Wound healing is a complex process that is easily affected by external factors. Existing medical dressings cannot reflect the healing status of wounds in real time. To ensure optimal wound healing management, the choice of dressing is crucial. Functional wound dressings can effectively help people monitor wounds and control wound infection. Changes in the pH value of wound exudate can well reflect changes in the wound. Therefore, developing dressings that can monitor and display the pH value of wound exudate is of great significance. It can assess the wound condition based on changes in the pH value of wound exudate, thereby enabling timely and rapid wound treatment. Therefore, developing medical dressings for this field is an urgent problem to be solved. Summary of the Invention

[0003] The purpose of this invention is to overcome the problems existing in the prior art and provide a composite fiber membrane that has good antibacterial effect and one-way moisture-wicking function, and can also change color under different pH environments, and has good application prospects in the field of medical dressings.

[0004] To achieve the above objectives, the present invention provides a composite fiber membrane, the composite fiber membrane comprising a pH-responsive fiber membrane, a hydrophobic fiber membrane distributed on one side of the pH-responsive fiber membrane, and a hydrophilic fiber membrane distributed on the other side of the pH-responsive fiber membrane.

[0005] The pH-responsive fiber membrane comprises polyethylene oxide, chitosan, and alizarin dye.

[0006] Preferably, the pH response range of the pH-responsive fiber membrane is 2-11.

[0007] Preferably, in the pH-responsive fiber membrane, the total weight ratio of polyethylene oxide and chitosan to alizarin dye is 1:0.1-1.

[0008] Preferably, in the pH-responsive fiber membrane, the weight ratio of polyethylene oxide to chitosan is 1:1-9.

[0009] Preferably, the contact angle of the hydrophobic fiber membrane is greater than 100°.

[0010] Preferably, the contact angle of the hydrophilic fiber membrane is less than 80°.

[0011] Preferably, the thickness of the hydrophobic fiber membrane is 10-50 μm.

[0012] Preferably, the thickness of the pH-responsive fiber membrane is 10-50 μm.

[0013] Preferably, the thickness of the hydrophilic fiber membrane is 10-50 μm.

[0014] A second aspect of the present invention provides a method for preparing a composite fiber membrane, the method comprising:

[0015] (1) Hydrophobic fiber membranes were prepared by electrospinning;

[0016] (2) A pH-responsive fiber membrane is formed on the hydrophobic fiber membrane prepared in step (1) by electrospinning.

[0017] (3) A hydrophilic fiber membrane is formed on the pH-responsive fiber membrane of the material obtained in step (2) by electrospinning.

[0018] (4) The material obtained in step (3) is reacted with a crosslinking agent;

[0019] The pH-responsive fiber membrane comprises polyethylene oxide, chitosan, and alizarin dye.

[0020] Preferably, the pH response range of the pH-responsive fiber membrane is 2-11.

[0021] Preferably, the thickness of the pH-responsive fiber membrane is 10-50 μm.

[0022] Preferably, the contact angle of the hydrophobic fiber membrane is greater than 100°.

[0023] Preferably, the thickness of the hydrophobic fiber membrane is 10-50 μm.

[0024] Preferably, the contact angle of the hydrophilic fiber membrane is less than 80°.

[0025] Preferably, the thickness of the hydrophilic fiber membrane is 10-50 μm.

[0026] Preferably, the method for preparing the pH-responsive fiber membrane includes the following steps:

[0027] A1: Mix polyethylene oxide and water and adjust the pH value to ≤6, then add chitosan and alizarin dye to obtain the second spinning solution;

[0028] A2: The second spinning solution is electrospun to obtain fibers, which are then vacuum dried.

[0029] Preferably, in step A1, the weight ratio of the total weight of polyethylene oxide and chitosan to the weight of water is 3-5:100.

[0030] Preferably, in step A1, the total weight ratio of polyethylene oxide and chitosan to alizarin dye is 1:0.1-1.

[0031] Preferably, in step A1, the weight ratio of polyethylene oxide to chitosan is 1:1-9.

[0032] Preferably, in step (4), the crosslinking agent is selected from glutaraldehyde, dopamine, epichlorohydrin or boric acid.

[0033] A third aspect of the present invention provides a composite fiber membrane prepared by the above method.

[0034] The fourth aspect of the present invention provides the application of the above-described composite fiber membrane in medical dressings.

[0035] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0036] (1) The composite fiber membrane of the present invention has good antibacterial effect and one-way moisture-wicking function, and can also change color under different pH environments.

[0037] (2) When the composite fiber membrane described in this invention is used in medical dressings, it has a good inhibitory effect on Escherichia coli and Staphylococcus aureus. At the same time, it can quickly drain wound exudate to the outer layer and effectively block the backflow of external liquids. It can effectively absorb wound exudate and create a good healing environment for the wound. In addition, the composite fiber membrane is sensitive to changes in the pH of wound exudate and can respond and change color within 30 seconds. The color change is obvious, thereby monitoring the healing status of the wound. Attached Figure Description

[0038] Figure 1 Air permeability and air permeability of the composite fiber membranes prepared in Examples 1-3;

[0039] Figure 2 This is a graph showing the water absorption and equilibrium water absorption of the composite fiber membranes prepared in Examples 1-3;

[0040] Figure 3 These are tensile strength diagrams of the composite fiber membranes prepared in Examples 1-3;

[0041] Figure 4 These are water permeability graphs of the composite fiber membranes prepared in Example 1 and Comparative Examples 1-2;

[0042] Figure 5 This is a color chart of the composite fiber membrane prepared in Example 1 in buffer solutions of different pH values;

[0043] Figure 6The graph shows the antibacterial properties of the composite fiber membranes prepared in Examples 1-3 and the blank control group. Detailed Implementation

[0044] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0045] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0046] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or implying the number of technical features indicated. Therefore, unless otherwise stated, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; "multiple" means two or more. The term "comprising" and any variations thereof mean non-exclusive inclusion, where one or more other features, integers, steps, operations, units, components, and / or combinations thereof may be present or added.

[0047] The present invention provides a composite fiber membrane, the composite fiber membrane comprising a pH-responsive fiber membrane, a hydrophobic fiber membrane distributed on one side of the pH-responsive fiber membrane, and a hydrophilic fiber membrane distributed on the other side of the pH-responsive fiber membrane;

[0048] The pH-responsive fiber membrane comprises polyethylene oxide, chitosan, and alizarin dye.

[0049] In a preferred embodiment, the pH response range of the pH-responsive fiber membrane is 2-11; within the above pH range, the color difference of the pH-responsive fiber membrane is obvious, and the pH value of the environment can be quickly determined based on the color change.

[0050] In a preferred embodiment, in order to improve the pH sensitivity of the pH-responsive fiber membrane, the total weight ratio of polyoxyethylene and chitosan to alizarin dye in the pH-responsive fiber membrane is 1:0.1-1; specifically, the total weight ratio of polyoxyethylene and chitosan to alizarin dye can be 1:0.1, 1:0.3, 1:0.5, 1:0.8 or 1:1.

[0051] In a preferred embodiment, in order to improve the spinnability and antibacterial properties of the pH-responsive fiber membrane, the weight ratio of polyethylene oxide to chitosan is 1:1-9; specifically, the weight ratio of polyethylene oxide to chitosan can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8 or 1:9.

[0052] In this invention, there are no special requirements for the material of the hydrophobic fiber membrane, as long as the fiber membrane prepared by the material is hydrophobic; in a preferred embodiment, the contact angle of the hydrophobic fiber membrane is greater than 100°.

[0053] In this invention, there are no special requirements for the material of the hydrophilic fiber membrane, as long as the fiber membrane prepared from the material is hydrophilic; in a preferred embodiment, the contact angle of the hydrophilic fiber membrane is less than 80°.

[0054] In a preferred embodiment, in order to maintain suitable hydrophobicity of the hydrophobic fiber membrane, the thickness of the hydrophobic fiber membrane is 10-50 μm; specifically, the thickness of the hydrophobic fiber membrane can be 10 μm, 20 μm, 30 μm, 40 μm or 50 μm.

[0055] In a preferred embodiment, in order to improve the pH responsiveness of the pH-responsive fiber membrane, the thickness of the pH-responsive fiber membrane is 10-50 μm; specifically, the thickness of the pH-responsive fiber membrane can be 10 μm, 20 μm, 30 μm, 40 μm or 50 μm.

[0056] In a preferred embodiment, in order to maintain suitable hydrophilicity of the hydrophilic fiber membrane, the thickness of the hydrophilic fiber membrane is 10-50 μm; specifically, the thickness of the hydrophilic fiber membrane can be 10 μm, 20 μm, 30 μm, 40 μm or 50 μm.

[0057] The composite fiber membrane described in this invention has excellent antibacterial effects and one-way moisture-wicking function. It can also change color under different pH environments. This is mainly because liquids can pass through the micropores of the hydrophobic fiber membrane due to the hydrophilicity of the outer hydrophilic fiber membrane, while external liquids will not backflow due to the hydrophobicity of the inner hydrophobic fiber membrane. This gives the composite fiber membrane one-way moisture-wicking function. The pH-responsive fiber membrane is highly sensitive to changes in acidity and alkalinity. Furthermore, the nanofibers have characteristics such as small diameter, high specific surface area, and porosity, which can quickly respond to changes in pH.

[0058] A second aspect of the present invention provides a method for preparing a composite fiber membrane, the method comprising:

[0059] (1) Hydrophobic fiber membranes were prepared by electrospinning;

[0060] (2) A pH-responsive fiber membrane is formed on the hydrophobic fiber membrane prepared in step (1) by electrospinning.

[0061] (3) A hydrophilic fiber membrane is formed on the pH-responsive fiber membrane of the material obtained in step (2) by electrospinning.

[0062] (4) The material obtained in step (3) is reacted with a crosslinking agent;

[0063] The pH-responsive fiber membrane comprises polyethylene oxide, chitosan, and alizarin dye.

[0064] In this invention, there are no special requirements for the conditions of electrospinning; conventional conditions in the art are acceptable. Preferably, the conditions for electrospinning include: a spinning voltage of 15-30KV, a spinning solution propulsion rate of 0.01-0.05mL / min, a receiving distance of 10-20cm, a fiber receiver rotation speed of 100-500rpm, and a spinning time of 0.5-5h.

[0065] In a preferred embodiment, the pH response range of the pH-responsive fiber membrane is 2-11; within the above pH range, the color difference of the pH-responsive fiber membrane is obvious, and the pH value of the environment can be quickly determined based on the color change.

[0066] In a preferred embodiment, in order to improve the pH responsiveness of the pH-responsive fiber membrane, the thickness of the pH-responsive fiber membrane is 10-50 μm; specifically, the thickness of the pH-responsive fiber membrane can be 10 μm, 20 μm, 30 μm, 40 μm or 50 μm.

[0067] In a preferred embodiment, the method for preparing the pH-responsive fiber membrane includes the following steps:

[0068] A1: Mix polyethylene oxide and water and adjust the pH value to ≤6, then add chitosan and alizarin dye to obtain the second spinning solution;

[0069] A2: The second spinning solution is electrospun to obtain fibers, which are then vacuum dried.

[0070] In this invention, there are no special requirements for the substance used to adjust the pH value to ≤6 in step A1, as long as it can adjust the pH value to ≤6. In a preferred embodiment, a buffer solution or an acidic solution can be used to adjust the pH value to ≤6; specifically, a 70wt% acetic acid solution can be used.

[0071] In a preferred embodiment, in order to improve the spinnability and performance of the pH-responsive nanofiber membrane, in step A1, the weight ratio of the total weight of polyethylene oxide and chitosan to water is 3-5:100; specifically, the weight ratio of the total weight of polyethylene oxide and chitosan to water can be 3:100, 4:100 or 5:100.

[0072] In a preferred embodiment, in order to improve the sensitivity of the pH-responsive fiber membrane to different pH values, in step A1, the total weight ratio of polyethylene oxide and chitosan to alizarin dye is 1:0.1-1; specifically, the total weight ratio of polyethylene oxide and chitosan to alizarin dye can be 1:0.1, 1:0.3, 1:0.5, 1:0.8 or 1:1.

[0073] In a preferred embodiment, in order to improve the spinnability and antibacterial properties of the pH-responsive fiber membrane, in step A1, the weight ratio of polyethylene oxide to chitosan is 1:1-9; specifically, the weight ratio of polyethylene oxide to chitosan can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8 or 1:9.

[0074] In this invention, there are no special requirements for the material of the hydrophobic fiber membrane, as long as the fiber membrane prepared by the material is hydrophobic; in a preferred embodiment, the contact angle of the hydrophobic fiber membrane is greater than 100°.

[0075] In a preferred embodiment, in order to maintain suitable hydrophobicity of the hydrophobic fiber membrane, the thickness of the hydrophobic fiber membrane is 10-50 μm; specifically, the thickness of the hydrophobic fiber membrane can be 10 μm, 20 μm, 30 μm, 40 μm or 50 μm.

[0076] In a preferred embodiment, the method for preparing the hydrophobic fiber membrane includes: mixing polymer compound A, polymer compound B, antibacterial agent and solvent A to obtain a first spinning solution, and then electrospinning the first spinning solution;

[0077] Wherein, the polymer compound A is selected from polyurethane, polystyrene, polylactic acid or zein;

[0078] The polymer compound B is selected from one or more of polyacrylonitrile, polyvinyl alcohol, hydroxyethyl cellulose, and sodium alginate.

[0079] In a preferred embodiment, in order to maintain suitable hydrophobicity of the hydrophobic fiber membrane, the weight ratio of polymer compound A to polymer compound B is 3:5-8.

[0080] In a preferred embodiment, in order to improve the spinning performance of the first spinning solution, the weight ratio of the total weight of polymer compound A and polymer compound B to the weight of solvent A is 1:1-5.

[0081] In this invention, there are no special requirements for solvent A, as long as it can dissolve polymer compound A and polymer compound B. In a preferred embodiment, solvent A is selected from N,N-dimethylformamide, tetrahydrofuran or acetone.

[0082] In this invention, there are no special requirements for the antibacterial agent; any antibacterial agent conventionally used in the art is acceptable. In a preferred embodiment, the antibacterial agent is a metal ion antibacterial agent and / or an organic antibacterial agent.

[0083] In this invention, there are no special requirements for the organic antibacterial agent; any organic antibacterial agent conventionally used in the art can be used, such as quaternary ammonium salt compounds, biguanide compounds, or haloamine compounds.

[0084] In this invention, there are no special requirements for the amount of the antibacterial agent, as long as it can make the hydrophobic fiber membrane have an antibacterial effect. Preferably, the weight ratio of the total weight of polymer compound A and polymer compound B to the weight of the antibacterial agent is 1:0.01-0.05.

[0085] In this invention, there are no special requirements for the material of the hydrophilic fiber membrane, as long as the fiber membrane prepared from the material is hydrophilic; in a preferred embodiment, the contact angle of the hydrophilic fiber membrane is less than 80°.

[0086] In a preferred embodiment, in order to maintain suitable hydrophilicity of the hydrophilic fiber membrane, the thickness of the hydrophilic fiber membrane is 10-50 μm; specifically, the thickness of the hydrophilic fiber membrane can be 10 μm, 20 μm, 30 μm, 40 μm or 50 μm.

[0087] In a preferred embodiment, the method for preparing the hydrophilic fiber membrane includes: mixing polymer compound C and solvent B to obtain a third spinning solution, and then electrospinning the third spinning solution;

[0088] The polymeric compound is selected from one or more of polyacrylonitrile, polyvinyl alcohol, hydroxyethyl cellulose, and sodium alginate.

[0089] In a preferred embodiment, in order to improve the spinning performance of the third spinning solution, the weight ratio of polymer compound C to solvent B is 1:1-5.

[0090] In this invention, there are no special requirements for the solvent B, as long as it can dissolve the polymer compound C. In a preferred embodiment, the solvent B is selected from N,N-dimethylformamide, tetrahydrofuran, or acetone.

[0091] In a preferred embodiment, in order to improve the strength of the composite fiber membrane, in step (4), the crosslinking agent is selected from glutaraldehyde, dopamine, epichlorohydrin or boric acid.

[0092] In this invention, there are no special requirements for the amount of crosslinking agent and the reaction time in step (4), as long as the material obtained in step (3) can be crosslinked.

[0093] In a specific implementation, in step (4), the material obtained in step (3) and the crosslinking agent or the crosslinking agent aqueous solution are placed in a vacuum drying oven. The material obtained in step (3) is placed on top of the crosslinking agent. The crosslinking agent evaporates in the vacuum drying oven, and the generated vapor causes the material obtained in step (3) to react. Then, the material is placed in a fume hood to remove the residual crosslinking agent and obtain a composite fiber membrane.

[0094] In a preferred embodiment, the temperature of the drying oven is 45-80°C.

[0095] A third aspect of the present invention provides a composite fiber membrane prepared by the above method.

[0096] The fourth aspect of the present invention provides the application of the above-described composite fiber membrane in medical dressings.

[0097] When the composite fiber membrane described in this invention is used in medical dressings, it has a good inhibitory effect on Escherichia coli and Staphylococcus aureus. At the same time, it can quickly drain wound exudate to the outer layer and effectively block the backflow of external liquids. It can effectively absorb wound exudate and create a good healing environment for the wound. In addition, the composite fiber membrane is sensitive to changes in the pH of wound exudate, and can respond and change color within 30 seconds with obvious color change, thereby monitoring the wound healing status.

[0098] The following examples further illustrate the composite fiber membrane, its preparation method, and its application according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0099] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available; C80A polyurethane was purchased from BASF Chemical (China) Co., Ltd.

[0100] Example 1

[0101] (1) Mix C80A polyurethane, polyacrylonitrile and solvent NN dimethylformamide, then add 0.3wt% silver nitrate solution, stir at 20℃ for 6h to obtain the first spinning solution S1, wherein the weight ratio of C80A polyurethane to polyacrylonitrile is 3:7, the weight ratio of the total weight of C80A polyurethane and polyacrylonitrile to solvent NN dimethylformamide is 1:1.5, and the weight ratio of the total weight of C80A polyurethane and polyacrylonitrile to silver nitrate is 1:0.02;

[0102] The first spinning solution S1 was injected into a syringe equipped with a 20G stainless steel needle for electrospinning. The electrospinning conditions included: a spinning voltage of 17KV, a spinning solution propulsion rate of 0.01mL / min, a receiving distance of 18cm, a fiber receiver rotation speed of 300rpm, and a spinning time of 1h, resulting in a hydrophobic fiber membrane L1 with a thickness of 10μm.

[0103] (2) A pH-responsive fiber membrane M1 was formed on the hydrophobic fiber membrane L1 by electrospinning. The preparation process is as follows:

[0104] A1: Polyoxyethylene and water were mixed and stirred for 6 hours to obtain a mixed solution. Then, the pH of the mixed solution was adjusted to 5 using a 70wt% acetic acid solution. Chitosan and alizarin dye were added sequentially and stirred for 2 hours to obtain the second spinning solution F1. The weight ratio of polyoxyethylene to chitosan was 1:2.3, the weight ratio of the total weight of polyoxyethylene and chitosan to water was 4:100, and the weight ratio of the total weight of polyoxyethylene and chitosan to alizarin dye was 1:0.5.

[0105] A2: After injecting the second spinning solution F1 into a syringe with a 20G stainless steel needle, the needle is aligned with the hydrophobic fiber membrane L1 for electrospinning. The conditions for electrospinning include: spinning voltage of 12KV, spinning solution propulsion rate of 0.02ml / min, receiving distance of 13cm (i.e., the vertical distance between the needle and the hydrophobic fiber membrane L1 is 13cm), fiber receiver rotation speed of 300rpm, and spinning time of 3h. After spinning, a pH-responsive fiber membrane M1 with a thickness of 20μm is formed on the hydrophobic fiber membrane L1.

[0106] (3) A hydrophilic fiber membrane N1 is formed on the pH-responsive fiber membrane M1 obtained in step (2) by electrospinning. The preparation process is as follows:

[0107] Polyacrylonitrile and solvent NN dimethylformamide were mixed and stirred at 20°C for 6 hours to obtain the third spinning solution K1, wherein the weight ratio of polyacrylonitrile to solvent NN dimethylformamide was 1:1.36.

[0108] After injecting the third spinning solution K1 into a syringe equipped with a 20G stainless steel needle, the needle was aligned with the pH-responsive fiber membrane M1 for electrospinning. The electrospinning conditions included: a spinning voltage of 15KV, a spinning solution propulsion rate of 0.01mL / min, a receiving distance of 15cm (i.e., a vertical distance of 13cm between the needle and the pH-responsive fiber membrane M1), a fiber receiver rotation speed of 300rpm, and a spinning time of 1h. After spinning, a hydrophilic fiber membrane N1 with a thickness of 8μm was formed on the pH-responsive fiber membrane M1.

[0109] (4) The material obtained in step (3) and the crosslinking agent glutaraldehyde are placed in a drying oven for reaction. The reaction temperature is 60°C and the reaction time is 12h. The material obtained in step (3) is placed on top of the crosslinking agent glutaraldehyde.

[0110] Example 2

[0111] The implementation was carried out in accordance with Example 1, except that the spinning time of the first spinning solution was 2 hours.

[0112] Example 3

[0113] The implementation was carried out in accordance with Example 1, except that the spinning time of the first spinning solution was 3 hours.

[0114] Example 4

[0115] The implementation was carried out in accordance with Example 1, except that the thickness of the pH-responsive fiber membrane was 70 μm.

[0116] Example 5

[0117] The implementation was carried out in accordance with Example 1, except that the thickness of the hydrophobic fiber membrane was 70 μm.

[0118] Example 6

[0119] The procedure was carried out in accordance with Example 1, except that the thickness of the hydrophilic fiber membrane was 5 μm.

[0120] Comparative Example 1

[0121] The implementation was carried out in accordance with Example 1, except that a hydrophobic fiber membrane L1 was used instead of a hydrophilic fiber membrane NI.

[0122] Comparative Example 2

[0123] The implementation was carried out in accordance with Example 1, except that a hydrophilic fiber membrane NI was used instead of a hydrophobic fiber membrane L1.

[0124] Test case

[0125] The performance of the composite fiber membranes prepared in the above embodiments and comparative examples was tested:

[0126] (1) Air permeability test: A sample of a certain size was placed on the test plate, and the sealing sheet was pressed tightly. The air permeability of the sample was measured using a YG461E digital air permeability meter (Ningbo Textile Instrument Factory, China). The sample pressure difference was set to 100 Pa, and the area of ​​the sample being tested was 25 cm². 2 Three points were randomly selected on the sample for testing, and the final results were averaged for statistical analysis. Figure 1 The air permeability and air permeability of the composite fiber membranes prepared in Examples 1-3 are shown in the following figures. Figure 1 (a) is the air permeability of the composite fiber membranes prepared in Examples 1-3. Figure 1 (b) is the air permeability of the composite fiber membranes prepared in Examples 1-3;

[0127] Depend on Figure 1 It can be seen that the composite fiber membranes prepared in Examples 1-3 have good air permeability.

[0128] (2) Water absorption test: The sample was placed in a vacuum drying oven and dried at 60℃ for 24 hours. It was then weighed and recorded as W0. After that, the sample was placed in a beaker containing deionized water and soaked for 2 hours. The sample was then removed, the surface moisture was wiped off with filter paper, and the sample was weighed and recorded as W1. The water absorption and equilibrium moisture content of the sample were calculated by the following formulas:

[0129]

[0130] Figure 2 This is a graph showing the water absorption and equilibrium water absorption of the composite fiber membranes prepared in Examples 1-3;

[0131] Depend on Figure 2 It can be seen that the composite fiber membranes prepared in Examples 1-3 have good water absorption.

[0132] (3) Mechanical property testing: The samples were cut into strips of 5mm × 40mm and subjected to tensile testing using a TA.TOUCH physical property tester. The distance between the upper and lower clamps was 20mm, and the tensile speed was 10mm / min. Three different samples were taken from each composite fiber membrane for testing, and the final result was the average value. Figure 3 These are tensile strength diagrams of the composite fiber membranes prepared in Examples 1-3;

[0133] Depend on Figure 3 It can be seen that the composite fiber membranes prepared in Examples 1-3 have excellent mechanical properties, with a maximum tensile strength at break of 4 MPa or higher.

[0134] (4) One-way water permeability test: Take a sample of a certain size and fix its two ends to the support. Continuously drop blue ink onto the center of the upper hydrophilic fiber membrane of the composite fiber membrane until ink seepage is observed in the lower hydrophobic fiber membrane of the composite fiber membrane. Record the volume of ink dropped at this time. Take the same amount of ink and drop it onto the center of the lower hydrophobic fiber membrane of the composite fiber membrane, and observe the ink seepage of the upper hydrophilic fiber membrane. Figure 4 These are water permeability graphs of the composite fiber membranes prepared in Example 1 and Comparative Examples 1-2, where... Figure 4 (a) is a graph showing the water permeability of the composite fiber membrane prepared in Example 1; where Figure 4 (b) shows the water permeability of the composite fiber membrane prepared in Comparative Example 1; where Figure 4 (c) is a graph showing the water permeability of the composite fiber membrane prepared in Comparative Example 2;

[0135] Depend on Figure 4 It can be seen that the composite fiber membrane prepared by the present invention has a one-way moisture-wicking function, and water can be guided from the hydrophobic layer to the hydrophilic layer but not from the hydrophilic layer to the hydrophobic layer; while the composite fiber membrane prepared in Comparative Example 1 has hydrophobic layers on both the upper and lower sides and does not have a moisture-wicking function; the composite fiber membrane prepared in Comparative Example 2 has hydrophilic layers on both the upper and lower sides and although it has a moisture-wicking function, its moisture-wicking function is bidirectional.

[0136] (5) pH responsiveness test: The pH of the PBS buffer was adjusted using hydrochloric acid and sodium hydroxide solutions, and the pH value of the solution was determined using a pH meter. Buffer solutions with pH values ​​of 2-11 were prepared to simulate wound exudate under different conditions. The composite fiber membranes prepared in the examples and comparative examples were immersed in buffer solutions with the same pH value, and the response time was recorded. The results are shown in Table 1. Then, the composite fiber membrane prepared in Example 1 was immersed in buffer solutions with different pH values ​​to observe the color change. Figure 5 This is a color chart of the composite fiber membrane prepared in Example 1 in buffer solutions of different pH values;

[0137] Depend on Figure 5 It can be seen that the composite fiber membrane prepared in Example 1 has a good response to different pH values, and its color change is significantly different with different pH values.

[0138] (6) Antibacterial test: The antibacterial properties of the samples were tested using the agar plate method. The bacterial strains used were Escherichia coli (E. coli) and Staphylococcus aureus (S. aereus). The activated bacterial solution was diluted to 3×10⁴ CFU / ml. 100 μL of the diluted bacterial solution was coated onto a high-temperature sterilized agar medium, ensuring uniform coating. The samples from Examples 1-3 were cut into 2 cm diameter discs. The discs were placed side by side on the coated agar. The culture medium was then sealed and placed in a biochemical incubator at 37±0.1℃ for 24 h. The blank control group consisted of the first spinning solution without added antibacterial agent. Figure 6 The graphs show the antibacterial properties of the composite fiber membranes prepared in Examples 1-3 and the blank control group.

[0139] Depend on Figure 6 It can be seen that the composite fiber membranes prepared in Examples 1-3 have excellent antibacterial properties.

[0140] Table 1

[0141] serial number Response time (s) serial number Response time (s) Example 1 20 Example 5 63 Example 2 25 Example 6 39 Example 3 38 Comparative Example 1 40 Example 4 45 Comparative Example 2 18

[0142] As can be seen from the results in Table 1, the composite fiber membrane described in this invention has excellent response performance to changes in pH value and a fast response speed. It can also distinguish different pH values ​​based on color changes.

[0143] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A composite fiber membrane, characterized in that, The composite fiber membrane includes a pH-responsive fiber membrane, a hydrophobic fiber membrane distributed on one side of the pH-responsive fiber membrane, and a hydrophilic fiber membrane distributed on the other side of the pH-responsive fiber membrane. The pH-responsive fiber membrane comprises polyethylene oxide, chitosan, and alizarin dye; In the pH-responsive fiber membrane, the total weight ratio of polyethylene oxide and chitosan to alizarin dye is 1:0.1-1; In the pH-responsive fiber membrane, the weight ratio of polyethylene oxide to chitosan is 1:1-9; The thickness of the hydrophobic fiber membrane is 10-50 μm; The thickness of the pH-responsive fiber membrane is 10-50 μm; The thickness of the hydrophilic fiber membrane is 10-50 μm.

2. The composite fiber membrane according to claim 1, characterized in that, The pH response range of the pH-responsive fiber membrane is 2-11.

3. The composite fiber membrane according to claim 1 or 2, characterized in that, The contact angle of the hydrophobic fiber membrane is greater than 100°.

4. The composite fiber membrane according to claim 3, characterized in that, The contact angle of the hydrophilic fiber membrane is less than 80°.

5. A method for preparing the composite fiber membrane according to any one of claims 1-4, characterized in that, The method includes: (1) Hydrophobic fiber membranes were prepared by electrospinning; (2) A pH-responsive fiber membrane is formed on the hydrophobic fiber membrane prepared in step (1) by electrospinning; (3) A hydrophilic fiber membrane is formed on the pH-responsive fiber membrane of the material obtained in step (2) by electrospinning; (4) The material obtained in step (3) is reacted with a crosslinking agent; The pH-responsive fiber membrane comprises polyethylene oxide, chitosan, and alizarin dye.

6. The method according to claim 5, characterized in that, The method for preparing the pH-responsive fiber membrane includes the following steps: A1: Mix polyethylene oxide and water and adjust the pH value to ≤6, then add chitosan and alizarin dye to obtain the second spinning solution; A2: The second spinning solution is electrospun to obtain fibers, which are then vacuum dried.

7. The method according to claim 6, characterized in that, In step A1, the total weight ratio of polyethylene oxide and chitosan to water is 3-5:

100.

8. The method according to any one of claims 5-7, characterized in that, In step (4), the crosslinking agent is selected from glutaraldehyde, dopamine, epichlorohydrin or boric acid.

9. The use of the composite fiber membrane according to any one of claims 1-4 in medical dressings.

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