Preparation method of breathable bacteria-isolating nanofiber membrane, breathable bacteria-isolating nanofiber membrane and breathable bacteria-isolating dressing

Abstract

This invention relates to a method for preparing a breathable and antibacterial nanofiber membrane, as well as the breathable and antibacterial nanofiber membrane and a breathable and antibacterial dressing. The preparation steps of the breathable and antibacterial nanofiber membrane are as follows: A hydrophobic polymer is added to solvent A to obtain spinning solution A; a conductivity modifier and a hydrophobic polymer are added to solvent B and mixed to obtain spinning solution B; spinning solution A is electrospun to obtain an outer nanofiber membrane; fibers obtained by electrospinning spinning solution B are received on the outer nanofiber membrane to form an inner nanofiber membrane; the composite fiber membrane formed by the outer and inner nanofiber membranes is the breathable and antibacterial nanofiber membrane. The breathable and antibacterial nanofiber membrane of this invention is breathable and antibacterial, has good drainage of wound exudate, is non-irritating to wounds, is not easily damaged, leaves no residue during dressing changes, has a simple process, and is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of medical wound care, and more specifically, to a method for preparing a breathable and antibacterial nanofiber membrane, the breathable and antibacterial nanofiber membrane, and a breathable and antibacterial dressing. Background Technology

[0002] Medical dressings are medical materials used to cover sores, wounds, or other damaged surfaces, primarily serving to protect the wound and promote healing. Traditional dressings, mainly gauze, bandages, cotton gauze, and adhesive bandages, only provide basic wound protection. However, existing medical dressings have several problems, such as not being waterproof, thus affecting patients' daily lives; adhering to the wound; failing to prevent external bacterial infection; poor wound conformability, making them difficult to apply to wounds in moving areas; and failing to promote wound healing.

[0003] To address the above drawbacks, some dressings use polyurethane semi-permeable membranes or polyethylene microporous membranes as the outer layer, which have good waterproof and bacterial barrier properties. However, polyurethane semi-permeable membranes are not conducive to wound healing or the drainage of wound exudate. Other dressings add antibacterial agents (such as silver ions) to prevent wound infection, but this presents a problem of drug resistance, while silver ions are cytotoxic and can damage organs such as the liver.

[0004] Therefore, there is a need to develop a medical dressing that has good drainage of wound exudate and effectively blocks external bacterial infection. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes a method for preparing a breathable and antibacterial nanofiber membrane, as well as the breathable and antibacterial nanofiber membrane and the breathable and antibacterial dressing thereof. The breathable and antibacterial nanofiber membrane and the breathable and antibacterial dressing prepared using the present invention are breathable and antibacterial, have good drainage of wound exudate, are non-irritating to wounds, are not easily damaged, leave no residue during dressing changes, and have a simple process suitable for industrial production.

[0006] One objective of this invention is to provide a method for preparing a breathable and bacteria-resistant nanofiber membrane, comprising the following steps:

[0007] (1) Preparation of spinning solution A: Add hydrophobic polymer to solvent A and dissolve it completely to obtain spinning solution A;

[0008] (2) Preparation of spinning solution B: Add conductivity regulator and hydrophobic polymer to solvent B, and dissolve them completely to obtain spinning solution B;

[0009] (3) Preparation of outer nanofiber membrane: The spinning solution A is electrospun to obtain an outer nanofiber membrane;

[0010] (4) Preparation of breathable and bacteria-proof nanofiber membrane: Fibers obtained by electrospinning the spinning solution B on the outer nanofiber membrane are received to form an inner nanofiber membrane; the composite fiber membrane formed by the outer nanofiber membrane and the inner nanofiber membrane is the breathable and bacteria-proof nanofiber membrane.

[0011] Solvent A is a mixed solvent, preferably a mixed solvent formed by an organic solvent with a boiling point greater than 100°C and a solvent with a boiling point of 100°C or less.

[0012] Solvent B is selected from one or a combination of organic solvents with a boiling point greater than 100°C.

[0013] In this invention, the means of achieving full dissolution in steps (1) and / or (2) are conventional technical means of the prior art, such as one or a combination of other means such as stirring and heating; there are no special requirements for heating temperature and stirring speed, as long as the purpose of achieving full dissolution can be achieved.

[0014] In this invention, except for temperature and humidity, the other spinning process parameters are selected or obtained by adjusting existing conventional process parameters. Preferably, the spinning process parameters for the outer nanofiber membrane are: spinning voltage 14-20KV, spinning distance 15-20cm, and spinning rate 0.5-1.5ml / h;

[0015] The spinning process parameters for the inner nanofiber membrane are: spinning voltage 13-17KV, spinning distance 10-16cm, and spinning rate 0.5-2ml / h.

[0016] Preferred,

[0017] In solvent A or solvent B, the organic solvents with boiling points greater than 100°C may be the same or different, and each is independently selected from one or a combination of dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, octane, toluene, formic acid, acetic acid, formamide, acetamide, butyl acetate, ethylene glycol, propylene glycol, butanol, cyclohexanone, cyclopentanone, or N-methylpyrrolidone.

[0018] In this invention, organic solvents with a boiling point greater than 100°C include, but are not limited to, the solvents mentioned above. Organic solvents commonly used in this boiling point range are also within the scope of this invention.

[0019] In solvent A, the solvent with a boiling point of 100°C or below is selected from one or a combination of tetrahydrofuran, acetone, chloroform, dichloromethane, trichloroethane, acetonitrile, n-hexane, cyclohexane, diethyl ether, methanol, ethanol, propanol, trifluoroethanol, hexafluoroisopropanol, ethyl acetate, trifluoroacetic acid, methyl ethyl ketone, or water; and / or,

[0020] In this invention, solvents with boiling points of 100°C and below include, but are not limited to, the solvents mentioned above. Commonly used organic solvents in this boiling point range are also within the scope of this invention.

[0021] In solvent A, the mass ratio of organic solvent with a boiling point greater than 100°C to solvent with a boiling point of 100°C or lower is 0.5-9:1.

[0022] Preferred,

[0023] The hydrophobic polymers in spinning solution A and spinning solution B may be the same or different, and are each independently selected from one or a combination of polyurethane, polycaprolactone silk fibroin, polyvinyl chloride, polystyrene, polyamide, polyhydroxybutyrate, polybutylene succinate, polybutylene adipate / terephthalate, polyethylene terephthalate, and polycarbonate.

[0024] In this invention, hydrophobic polymers include, but are limited to, the types of substances mentioned above. Commonly used hydrophobic polymers are also within the scope of this invention.

[0025] Preferred,

[0026] In the spinning solution A, the concentration of the hydrophobic polymer is 12 wt% to 25 wt%; more preferably 14 wt% to 25 wt%; and / or,

[0027] The concentration of hydrophobic polymer in the spinning solution B is 6 wt% to 12 wt%; more preferably 6 wt% to 10 wt%; and / or,

[0028] The concentration of the conductivity modifier is 0.001 wt% to 3 wt%, preferably 0.01 wt% to 1 wt%.

[0029] Preferred,

[0030] The conductivity modifier is selected from one or a combination of inorganic salts, ionic surfactants, quaternary ammonium salts, water, hydrochloric acid, or acetic acid.

[0031] Preferred,

[0032] The inorganic salt is selected from one or a combination of sodium chloride and lithium chloride; and / or,

[0033] The ionic surfactant is selected from one or a combination of sodium dodecylbenzenesulfonate or sodium dodecyl sulfonate; and / or,

[0034] The quaternary ammonium salt is selected from one or a combination of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, alkyldimethylbenzylammonium chloride, or octyldecyldimethylammonium chloride.

[0035] Preferred,

[0036] In step (3), the electrospinning temperature is above 10℃ and the spinning humidity is above 10%; and / or,

[0037] In step (4), the electrospinning temperature is above 30°C and the spinning humidity is above 40%.

[0038] Preferred,

[0039] In step (3), the electrospinning temperature is 10–30°C, and the spinning humidity is 10%–50%; and / or,

[0040] In step (4), the electrospinning temperature is 30-50℃ and the spinning humidity is 40%-90%.

[0041] A second objective of this invention is to provide a breathable and bacteria-proof nanofiber membrane prepared by a preparation method according to one objective of this invention, wherein the average pore size between fibers in the outer nanofiber membrane is larger than the average pore size between fibers in the inner nanofiber membrane.

[0042] Preferred,

[0043] In the breathable and antibacterial nanofiber membrane

[0044] In the outer nanofiber membrane, the average fiber diameter is 350-800 nm; the average pore size between fibers is 400 nm-800 nm; and the thickness is 10-200 micrometers. Preferably, in the outer nanofiber membrane, the average fiber diameter is 500-800 nm; and the average pore size between fibers is 500 nm-800 nm.

[0045] In the inner nanofiber membrane, the average fiber diameter is 50 nm to 300 nm; the average pore size between fibers is 50 nm to 300 nm; and the thickness is 10 to 200 micrometers. Preferably, in the inner nanofiber membrane, the average fiber diameter is 50 nm to 100 nm; and the average pore size between fibers is 50 nm to 200 nm.

[0046] The fibers in the inner nanofiber membrane adhere to each other at their overlapping points.

[0047] The third objective of this invention is to provide a breathable and antibacterial dressing prepared from the breathable and antibacterial nanofiber membrane of the second objective of this invention.

[0048] Invention principle:

[0049] This invention utilizes both low-boiling-point and high-boiling-point solvents for the outer nanofiber membrane. The low-boiling-point solvent evaporates more easily during spinning, resulting in coarser fiber diameters and larger pore sizes compared to using only a high-boiling-point solvent. The inner nanofiber membrane, on the other hand, uses only a high-boiling-point solvent, producing finer nanofibers with smaller pore sizes. During the preparation of the inner nanofiber membrane, a higher spinning temperature ensures the complete evaporation of residual solvent, preventing the fibers from dissolving. The large pore size of the outer nanofiber membrane and the small pore size of the inner nanofiber membrane create a capillary-like conical connecting pore between the two layers when forming a medical dressing. As the nanofiber material is hydrophobic, the capillary effect allows for the application of pressure—higher pressure on the inner nanofiber membrane and lower pressure on the outer membrane—to drain wound exudate outwards, creating one-way permeability and improving water resistance.

[0050] Electrospinning typically uses a humidity level of 20-40%. High humidity hinders solvent evaporation, and residual solvent can easily lead to fiber collapse, fiber adhesion, and poor fiber diameter uniformity. The inner nanofiber membrane of this invention is spun using a high-boiling-point solvent. In a high-humidity environment, this inhibits solvent evaporation, preventing fiber adhesion. Simultaneously, increasing the spinning temperature also avoids excessive residual solvent, which could cause fiber collapse and adhesion. The addition of a conductivity modifier improves conductivity and, in combination with other components, reduces fiber diameter and improves fiber uniformity. The water and saline solution in the conductivity modifier evaporate during spinning, leaving no harmful residues.

[0051] Compared with the prior art, the present invention has the following advantages:

[0052] The breathable and antibacterial nanofiber membrane of this invention blocks bacteria and prevents wound infection, achieving a 100% bacterial barrier rate, while also exhibiting high breathability with a non-contact steam permeability as high as 8365 g / (m²). 2 • 24h), while the commercially available Smith & Nephew "Alevert" film dressing has a non-contact vapor permeability of only 1260g / (m²). 2 • 24h); and meet the waterproof requirements for medical dressings;

[0053] The breathable and antibacterial nanofiber membrane of this invention features inner layer fibers that adhere to each other, enhancing the tensile strength of the finer fibers. Compared to fibers that are merely overlapped without any adhesion points, the inner layer fiber membrane of this invention has higher strength. The outer layer fibers of this invention have a larger diameter and also higher strength. Furthermore, the presence of residual solvent in the inner layer fibers causes them to adhere to the outer fibers, forming a composite fiber membrane with high overall strength that is not easily delaminated. During use, the breathable and antibacterial nanofiber membrane of this invention is not prone to delamination, is not easily damaged by friction, and does not lose its barrier effect. It also does not remain on the wound surface during dressing changes, thus preventing tissue inflammation.

[0054] The breathable and antibacterial nanofiber membrane of this invention is made of hydrophobic material and features a two-layer nanofiber membrane structure. The outer layer has a large pore size, while the inner layer has a small pore size, forming a conical interconnected pore. Utilizing the capillary effect, the inner layer experiences a higher additional pressure than the outer layer, thus allowing water to drain from the inside to the outside, creating one-way permeability and improving water resistance.

[0055] Electrospinning to prepare nanofiber membranes involves the random stacking of nanofibers. The pores formed by the interlacing of fibers are of uneven size, and defects may exist in localized areas during industrial production. Using a single membrane makes it virtually impossible to achieve 100% bacterial barrier function. Since bacteria range in size from 0.5 to 6 micrometers, this invention employs a composite of two layers of nanofiber membranes with gradient pore sizes. This ensures that the pore size of the composite, breathable, and antibacterial nanofiber membrane is completely less than 500 nm, and also eliminates the influence of localized defects, guaranteeing 100% bacterial barrier function and meeting the antibacterial performance requirements of medical dressings (the national standard for antibacterial performance of medical dressings requires 100% bacterial barrier function).

[0056] The breathable and antibacterial nanofiber membrane of the present invention is non-irritating to wounds, has a simple manufacturing process, and is suitable for industrial production. Attached Figure Description

[0057] Figure 1 This is a SEM image of the breathable and antibacterial nanofiber membrane of the present invention.

[0058] Figure 2 This is a SEM image of the nanofiber membrane prepared in the comparative example of the present invention.

[0059] Figure 3 This is a schematic diagram of the structure of the breathable and antibacterial dressing of the present invention.

[0060] Explanation of reference numerals in the attached figures:

[0061] 1-Release paper, 2-Adhesive layer, 3-Breathable and antibacterial nanofiber membrane. Detailed Implementation

[0062] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0063] Raw material source:

[0064] All raw materials used in this invention are conventional commercially available products.

[0065] Test method:

[0066] The antibacterial test was conducted in accordance with the test method in Part 5: Antibacterial properties of contact wound dressings in medical standard YY / T0471.5-2017.

[0067] The water vapor transmission rate test shall be conducted in accordance with the test method in YY / T0471.2-2004 Test Methods for Contact Wound Dressings Part 2: Water Vapor Transmission Rate of Breathable Membrane Dressings.

[0068] The waterproof performance was tested according to the test methods in YY / T0471.3-2004 Test Methods for Contact Wound Dressings Part 3: Water Resistance.

[0069] Mechanical properties are in accordance with GB / T1040.3-2006 Determination of tensile properties of plastics - Part 3: Test conditions for thin plastics and sheets.

[0070] Example 1

[0071] First, polyurethane was added to a mixed solvent with a mass ratio of dimethylformamide:tetrahydrofuran = 2:1, and the mixture was heated and stirred at 60°C for 12 hours to prepare spinning solution A. The concentration of polyurethane in spinning solution A was 18 wt%.

[0072] Sodium chloride was then added to the dimethylformamide solvent and stirred until homogeneous. Polyurethane was then added and the mixture was heated and stirred at 60°C for 12 hours to prepare spinning solution B. In spinning solution B, the concentration of sodium chloride was 0.05 wt% and the concentration of polyurethane was 10 wt%.

[0073] First, add spinning solution A to the electrospinning equipment and perform electrospinning to prepare the outer nanofiber membrane; the spinning parameters of the outer nanofiber membrane are: spinning temperature 20℃, humidity 20%, spinning voltage 15KV, spinning distance 15cm, and spinning rate 1ml / h.

[0074] Then, spinning solution B was added to the electrospinning equipment, and spinning continued on the outer nanofiber membrane to prepare the inner nanofiber membrane. This composite nanofiber membrane is a breathable and bacteria-proof nanofiber membrane. The spinning parameters for the inner nanofiber membrane are: spinning temperature 30℃, humidity 40%, spinning voltage 17KV, spinning distance 15cm, and spinning rate 1ml / h.

[0075] In the breathable and bacteria-proof nanofiber membrane prepared by the above method, the outer nanofiber membrane is 100 micrometers thick, the average diameter of the nanofibers is 500 nm, and the average pore size between the fibers is 550 nm; the inner nanofiber membrane is 100 micrometers thick, the average diameter of the fibers is 200 nm, and the average pore size between the fibers is 200 nm. In the inner nanofiber membrane, the fibers are adhered to each other and to the outer fibers.

[0076] This breathable, antibacterial nanofiber membrane can block 100% bacterial penetration, meeting the requirements for medical dressings. Its water vapor permeability is 7202 g / (m²). 2 • 24h); It can withstand 500mm hydrostatic pressure for 3min, meeting the water-blocking performance requirements of medical dressings; The tensile strength of the nanofiber membrane is 13MPa.

[0077] Example 2

[0078] First, polyethylene terephthalate was added to a mixed solvent with a mass ratio of dimethylformamide:trifluoroethanol = 1:2, and stirred and dissolved for 12 hours to prepare spinning solution A. The concentration of polyethylene terephthalate in spinning solution A was 14 wt%.

[0079] Acetic acid was then added to toluene solvent and stirred until homogeneous. Polycaprolactone was then added and stirred for 12 hours to prepare spinning solution B. In spinning solution B, the concentration of acetic acid was 0.001 wt% and the concentration of polycaprolactone was 6 wt%.

[0080] First, add spinning solution A to the electrospinning equipment and perform electrospinning to prepare the outer nanofiber membrane. The spinning parameters of the outer nanofiber membrane are: spinning temperature 30℃, humidity 50%, spinning voltage 14KV, spinning distance 15cm, and spinning rate 1.2ml / h.

[0081] Then, spinning solution B was added to the electrospinning equipment, and spinning continued on the outer nanofiber membrane to prepare the inner nanofiber membrane. This composite nanofiber membrane is a breathable and bacteria-proof nanofiber membrane. The spinning parameters of the inner nanofiber membrane are: spinning temperature 40℃, humidity 60%, spinning voltage 13KV, spinning distance 10cm, and spinning rate 1.5ml / h.

[0082] In the breathable and bacteria-proof nanofiber membrane prepared by the above method, the outer nanofiber membrane is 200 micrometers thick, the average diameter of the nanofibers is 600 nm, and the average pore size between the fibers is 650 nm; the inner nanofiber membrane is 200 micrometers thick, the average diameter of the fibers is 300 nm, and the average pore size between the fibers is 300 nm. In the inner nanofiber membrane, the fibers are adhered to each other and to the outer fibers.

[0083] This breathable, antibacterial nanofiber membrane can block 100% bacterial penetration, meeting the requirements for medical dressings. Its water vapor permeability is 8365 g / (m²). 2 •24h). It can withstand 500mm hydrostatic pressure for 3 minutes, meeting the water-blocking performance requirements of medical dressings; the tensile strength of the nanofiber membrane is 10MPa.

[0084] Example 3

[0085] First, polyurethane was added to a mixed solvent with a mass ratio of dimethylformamide:tetrahydrofuran = 3:1, and the mixture was heated and stirred at 60°C for 12 hours to dissolve it, thus preparing spinning solution A. The concentration of polyurethane in spinning solution A was 25 wt%.

[0086] Sodium dodecylbenzenesulfonate was then added to dimethylformamide and mixed thoroughly. Polyhydroxybutyrate was then added and stirred for 12 hours to dissolve completely. Spinning solution B was then prepared, in which the concentration of sodium dodecylbenzenesulfonate was 2 wt% and the concentration of polyhydroxybutyrate was 8 wt%.

[0087] First, spinning solution A is added to the electrospinning equipment to perform electrospinning and prepare the outer nanofiber membrane. The spinning parameters of the outer nanofiber membrane are: spinning temperature 10℃, humidity 10%, spinning voltage 20KV, spinning distance 20cm, and spinning rate 0.5ml / h.

[0088] Then, spinning solution B was added to the electrospinning equipment, and spinning continued on the outer nanofiber membrane to prepare the inner nanofiber membrane. This composite nanofiber membrane is a breathable and bacteria-proof nanofiber membrane. The spinning parameters for the inner nanofiber membrane are: spinning temperature 50℃, humidity 90%, spinning voltage 17KV, spinning distance 16cm, and spinning rate 2ml / h.

[0089] In the breathable and antibacterial nanofiber membrane prepared by the above method, the outer nanofiber membrane is 10 micrometers thick, the average diameter of the nanofibers is 800 nm, and the average pore size between the fibers is 800 nm. The inner nanofiber membrane is 100 micrometers thick, the average diameter of the fibers is 100 nm, and the average pore size between the fibers is 100 nm. The fibers are adhered to each other and to the outer fibers (e.g., ...). Figure 1 (As shown).

[0090] This breathable, antibacterial nanofiber membrane can block 100% bacterial penetration, meeting the requirements for medical dressings. Its water vapor permeability is 7570 g / (m²). 2 • 24h); It can withstand 500mm hydrostatic pressure for 3min, meeting the water-blocking performance requirements of medical dressings; The tensile strength of the nanofiber membrane is 11MPa.

[0091] Example 4

[0092] First, polyamide 6 is added to a mixed solvent with a mass ratio of formic acid:water = 9:1, stirred and dissolved, and stirred for 12 hours until completely dissolved to prepare spinning solution A. The concentration of polyamide 6 in spinning solution A is 20 wt%.

[0093] Then, silk fibroin was added to water to a solution concentration of 10 wt%, and 0.005 wt% dimethyloctadecyltrimethoxysilylpropylammonium chloride was added. The mixture was heated and stirred for 12 h to dissolve the fibroin, thus preparing spinning solution B. In spinning solution B, the concentration of silk fibroin was 10 wt%, and the concentration of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride was 0.005 wt%.

[0094] First, add spinning solution A to the electrospinning equipment and perform electrospinning to prepare the outer nanofiber membrane. The spinning parameters of the outer nanofiber membrane are: spinning temperature 150℃, humidity 25%, spinning voltage 20KV, spinning distance 20cm, and spinning rate 1.5ml / h.

[0095] Then, spinning solution B was added to the electrospinning equipment, and spinning continued on the outer nanofiber membrane to prepare the inner nanofiber membrane. This composite nanofiber membrane is a breathable and bacteria-proof nanofiber membrane. The spinning parameters of the inner nanofiber membrane are: spinning temperature 40℃, humidity 50%, spinning voltage 16KV, spinning distance 16cm, and spinning rate 0.5ml / h.

[0096] In the breathable and bacteria-proof nanofiber membrane prepared by the above method, the outer nanofiber membrane is 70 micrometers thick, the average diameter of the nanofibers is 350 nm, and the average pore size between the fibers is 400 nm; the inner nanofiber membrane is 10 micrometers thick, the average diameter of the fibers is 50 nm, the average pore size between the fibers is 50 nm, the fibers are adhered to each other, and also adhered to the outer fibers.

[0097] This breathable, antibacterial nanofiber membrane can block 100% bacterial penetration, meeting the requirements for medical dressings. Its water vapor permeability is 6123 g / (m²). 2 • 24h); It can withstand 500mm hydrostatic pressure for 3min, meeting the water-blocking performance requirements of medical dressings; The tensile strength of the nanofiber membrane is 12MPa.

[0098] The breathable and antibacterial dressings prepared in the embodiments of the present invention have good biocompatibility and are non-irritating to tissues; they do not adhere to wounds, and the fibers adhere to each other, so they will not remain on the wound surface during dressing changes and cause inflammation; they are elastic, conform well to the skin, and can be used on active areas; at the same time, the breathable and antibacterial dressings are also waterproof, making life more convenient for patients.

[0099] Comparative Example 1

[0100] The preparation method is the same as that of Example 1, except that only the outer nanofiber membrane of Example 1 is prepared.

[0101] The bacterial barrier test results showed that the outer nanofiber membrane could not effectively block bacteria and therefore failed to meet the waterproof performance requirements. Its tensile strength was 5 MPa, and its water vapor permeability was 8156 g / (m²). 2 •24h).

[0102] Electrospinning nanofiber membranes are formed by the random stacking of nanofibers. The pores created by the interlacing of fibers are of uneven size. Although the average pore size of the nanofiber membrane in Comparative Example 1 is 550 nm, it cannot be guaranteed that all pore sizes are smaller than 550 nm. Furthermore, defects may exist in localized areas of the nanofiber membrane during industrial production. Therefore, bacteria with a size of approximately 0.5-6 micrometers can penetrate the outer nanofiber membrane, making it impossible for the fiber membrane to achieve 100% bacterial barrier performance and meet the requirements for bacterial barrier properties in medical dressings (the national standard for bacterial barrier performance of medical dressings requires 100% bacterial barrier performance).

[0103] Comparative Example 2

[0104] The preparation method is the same as that in Example 1, except that the spinning parameters of the outer nanofiber membrane are: spinning temperature 20°C, humidity 20%, and the spinning parameters of the inner nanofiber membrane are: spinning temperature 20°C, humidity 20%.

[0105] In the nanofiber membrane prepared by the above method, the outer nanofiber membrane is 100 micrometers thick, the average diameter of the nanofibers is 500 nm, and the average pore size between the fibers is 550 nm. The nanofiber membrane itself is 100 micrometers thick, the average diameter of the fibers is 300 nm, and the average pore size between the fibers is 1100 nm. Numerous pores caused by droplets appear on the fiber membrane (e.g., ...). Figure 2 (As shown).

[0106] The results of the bacterial barrier test showed that it could not block bacteria and could not meet the waterproof performance requirements. Its tensile strength was 4 MPa.

[0107] Comparative Example 3

[0108] The preparation method is the same as that in Example 1, except that sodium chloride is not added during the preparation of the inner nanofiber membrane.

[0109] In the nanofiber membrane prepared by the above method, the outer nanofiber membrane is 100 micrometers thick, the average diameter of the nanofibers is 500 nm, and the average pore size between the fibers is 550 nm. The inner nanofiber membrane is 100 micrometers thick, the average diameter of the fibers is 430 nm, and the average pore size between the fibers is 500 nm.

[0110] The bacterial barrier test results showed that it could not block bacteria, with a strength of 7 MPa and a water vapor transmission rate of 4900 g / (m²). 2 • 24h) can meet the waterproof requirements. Although Comparative Example 3 also has a large pore size of the outer nanofiber membrane and a small pore size of the outer nanofiber membrane, the difference in pore size between the two membranes is relatively small, the drainage effect of the gradient pore size is weak, and the water vapor permeability is low.

[0111] Comparative Example 4

[0112] The preparation method is the same as that of Example 1, except that only the inner nanofiber membrane of Example 1 is prepared.

[0113] The nanofiber membrane prepared by the above method ruptures under a hydrostatic pressure of 500 mm, failing to meet the waterproof performance requirements. Its tensile strength is 2.1 MPa, and its water vapor permeability is 5310 g / (m²). 2 •24h).

[0114] The breathable and antibacterial dressing of the present invention has a conventional dressing structure in the prior art, including a breathable and antibacterial nanofiber membrane 3, an adhesive layer 2, and a release paper 1.

[0115] The adhesive layer can be a breathable single-sided adhesive applied to the back of the breathable and antibacterial nanofiber membrane (the back refers to the side away from the skin), or a breathable double-sided adhesive applied to the edge of the breathable and antibacterial nanofiber membrane, or the adhesive can be applied directly to the edge of the breathable and antibacterial nanofiber membrane. The adhesive layer ensures that the edges of the dressing are sealed to the skin, preventing water and bacteria from entering the wound from the edges, and also preventing wound exudate from flowing out. When using the breathable and antibacterial dressing of the present invention, the inner nanofiber membrane in the breathable and antibacterial nanofiber membrane faces the wound (i.e., adheres tightly to the wound).

[0116] The specific structure of the breathable and antibacterial dressing of the present invention includes, but is not limited to, similar to, Figure 3 The dressing structure is shown. A single-sided non-woven fabric tape (i.e., adhesive layer 2) is attached to the back of the breathable and antibacterial nanofiber membrane 3, and release paper 1 is attached to the front to prepare a breathable and antibacterial dressing.

Claims

1. A method for preparing a breathable and antibacterial dressing, characterized in that, The breathable and antibacterial dressing includes a breathable and antibacterial nanofiber membrane, an adhesive layer, and a release paper; the adhesive layer is attached to the back of the breathable and antibacterial nanofiber membrane, and the release paper is attached to the front of the breathable and antibacterial nanofiber membrane. The method for obtaining the breathable and antibacterial nanofiber membrane includes the following steps: (1) Preparation of spinning solution A: Add hydrophobic polymer to solvent A and dissolve it completely to obtain spinning solution A; (2) Preparation of spinning solution B: Add conductivity regulator and hydrophobic polymer to solvent B, and dissolve them completely to obtain spinning solution B; (3) Preparation of outer nanofiber membrane: The spinning solution A is electrospun to obtain an outer nanofiber membrane; (4) Preparation of breathable and bacteria-proof nanofiber membrane: Fibers obtained by electrospinning the spinning solution B on the outer nanofiber membrane are received to form an inner nanofiber membrane; the composite fiber membrane formed by the outer nanofiber membrane and the inner nanofiber membrane is the breathable and bacteria-proof nanofiber membrane. Solvent A is a mixed solvent, selected from a mixture of an organic solvent with a boiling point greater than 100°C and a solvent with a boiling point of 100°C or below; Solvent B is selected from one or a combination of organic solvents with a boiling point greater than 100°C, or Solvent B is selected from water; the organic solvents with a boiling point greater than 100°C in Solvent A or Solvent B may be the same or different, and each is independently selected from one or a combination of dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, octane, toluene, formic acid, acetic acid, formamide, acetamide, butyl acetate, ethylene glycol, propylene glycol, butanol, cyclohexanone, cyclopentanone, or N-methylpyrrolidone; In solvent A, the solvent with a boiling point of 100°C or below is selected from one or a combination of tetrahydrofuran, chloroform, dichloromethane, trichloroethane, acetonitrile, n-hexane, cyclohexane, diethyl ether, methanol, ethanol, propanol, trifluoroethanol, hexafluoroisopropanol, ethyl acetate, trifluoroacetic acid, methyl ethyl ketone or water. In step (3), the electrospinning temperature is 10~30℃ and the spinning humidity is 10%~50%; In step (4), the electrospinning temperature is 30~50℃ and the spinning humidity is 40%~90%; In the outer nanofiber membrane, the average pore size between fibers is 400nm to 800nm; in the inner nanofiber membrane, the average pore size between fibers is 50 to 300nm; and the overall pore size of the breathable and bacteria-proof nanofiber membrane is less than 500nm. The fibers in the inner nanofiber membrane adhere to each other at their overlapping points and also adhere to the fibers in the outer nanofiber membrane; the air-permeable and bacteria-barrier nanofiber membrane has a bacterial barrier rate of 100%. The concentration of hydrophobic polymer in the spinning solution A is 14 wt%~25 wt%. In the spinning solution B, the concentration of hydrophobic polymer is 6 wt%~10 wt%; the concentration of conductivity modifier is 0.01 wt%~1 wt%.

2. The method for preparing the breathable and antibacterial dressing according to claim 1, characterized in that: In solvent A, the mass ratio of organic solvent with a boiling point greater than 100°C to solvent with a boiling point of 100°C or lower is 0.5-9:

1.

3. The method for preparing the breathable and antibacterial dressing according to claim 1, characterized in that: The hydrophobic polymers in spinning solution A and spinning solution B may be the same or different, and are each independently selected from one or a combination of polyurethane, polycaprolactone, silk fibroin, polyvinyl chloride, polystyrene, polyamide, polyhydroxybutyrate, polybutylene succinate, polybutylene adipate / terephthalate, polyethylene terephthalate, or polycarbonate.

4. The method for preparing the breathable and antibacterial dressing according to claim 1, characterized in that: The conductivity modifier is selected from one or a combination of inorganic salts, ionic surfactants, quaternary ammonium salts, water, hydrochloric acid, or acetic acid.

5. The method for preparing the breathable and antibacterial dressing according to claim 4, characterized in that: The inorganic salt is selected from one or a combination of sodium chloride and lithium chloride; The ionic surfactant is selected from one or a combination of sodium dodecylbenzene sulfonate or sodium dodecyl sulfonate. The quaternary ammonium salt is selected from one or a combination of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, alkyldimethylbenzylammonium chloride, or octyldecyldimethylammonium chloride.

6. The method for preparing the breathable and antibacterial dressing according to claim 1, characterized in that: In the breathable and antibacterial nanofiber membrane The outer nanofiber membrane has an average fiber diameter of 350-500 nm and a thickness of 10-200 micrometers. The inner nanofiber membrane has an average fiber diameter of 50 nm to 200 nm and a thickness of 10 to 200 micrometers.

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