Nanofiber / wheat gluten protein foam composite medical dressing and method of making same

Abstract

The application discloses a kind of nanofiber / wheat gluten protein foam composite medical dressings and preparation method thereof, and preparation method includes the following steps: wheat gluten protein powder, plasticizer and alkali are dispersed in water, polyvinyl alcohol is added after heating and shearing stirring, and the wheat gluten protein foam is obtained after freeze-drying;Sodium alginate, polyvinyl alcohol and carboxymethyl chitosan aqueous solution are mixed to obtain electrospinning solution;Calcium chloride aqueous solution is coated on the wheat gluten protein foam, and electrospinning is carried out using electrospinning solution, to obtain nanofiber / wheat gluten protein foam composite medical dressing.The application takes wheat gluten protein foam as base layer, and takes sodium alginate / polyvinyl alcohol / carboxymethyl chitosan nanofiber membrane as surface layer (wound contact layer) to prepare a kind of composite medical dressing, which has excellent liquid absorption rate, micro-nano porous structure on the wound contact surface, and can be biodegraded, to provide a new type of composite medical dressing for the nursing of chronic wound.

Description

Technical Field

[0001] This invention relates to the field of medical dressing technology, specifically to a nanofiber / wheat gluten protein foam composite medical dressing and its preparation method. Background Technology

[0002] Medical dressings function to protect wounds, provide physical pressure to stop bleeding, and absorb wound exudate. Wounds can be divided into three main categories: chronic wounds, traumatic wounds, and surgical wounds. Typical examples of chronic wounds include pressure ulcers, diabetic foot ulcers, and leg ulcers. Chronic wounds are difficult to heal and are prone to producing large amounts of exudate. This exudate, remaining at the wound site, can irritate the wound, causing infection and inflammation, and may even lead to wound enlargement, hindering healing. Dressings used for this type of wound should have good biocompatibility, absorb large amounts of exudate, and have antibacterial properties.

[0003] Foam-based medical dressings have a porous structure and strong liquid absorption capacity, making them ideal for wounds with heavy exudation. Currently, foam-based medical dressings with polyurethane and polyester as base materials are quite common. These materials are derived from petroleum-based resources, are not easily degradable, and are detrimental to environmental protection and sustainable development. Furthermore, these dressings mostly involve the foam material directly adhering to the wound; from the perspective of the material itself and the microstructure of the foam, they offer no advantage for wound healing. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a nanofiber / wheat gluten protein foam composite medical dressing and its preparation method.

[0005] The above-mentioned objective of this invention is achieved through the following technical solutions:

[0006] A method for preparing a nanofiber / wheat gluten protein foam composite medical dressing includes the following steps:

[0007] (1) Wheat gluten protein powder, plasticizer and alkali are dispersed in water to obtain wheat gluten protein dispersion. The wheat gluten protein dispersion is heated and sheared and stirred. Then polyvinyl alcohol (PVA) is added and mixed evenly. After freeze drying, wheat gluten protein foam is obtained.

[0008] (2) Mix sodium alginate aqueous solution, polyvinyl alcohol aqueous solution and carboxymethyl chitosan (CMCS) aqueous solution to obtain electrospinning solution;

[0009] (3) Coat one side of the wheat gluten protein foam obtained in step (1) with a divalent metal cation aqueous solution and perform electrospinning using the electrospinning solution obtained in step (2). At the same time, perform air suction treatment on the other side of the wheat gluten protein foam to obtain the nanofiber / wheat gluten protein foam composite medical dressing.

[0010] Wheat gluten protein, a byproduct of wheat starch production, is a biodegradable plant protein that is inexpensive and readily available. Its unique glutenin and gliadin components give it excellent viscoelasticity, making it suitable for developing foam products. Sodium alginate is a natural polysaccharide extracted from brown algae such as kelp or Sargassum. It is abundant, environmentally friendly, and possesses advantages such as biocompatibility, biodegradability, non-toxicity, and non-adhesion to wounds. Polyvinyl alcohol (PVA) is a widely used synthetic biopolymer with high stability, water solubility, and good mechanical strength, often used to blend with natural materials for electrospinning. Carboxymethyl chitosan is a water-soluble chitosan derivative with numerous medical benefits, such as promoting wound healing, hemostasis, scar inhibition, analgesia, and antibacterial effects. Nanofiber membranes doped with carboxymethyl chitosan and based on sodium alginate and PVA as a binary polymer matrix can be prepared by electrospinning. The high specific surface area and high porosity of nanofibers facilitate cell respiration and gas permeation, providing physical support for cells and creating an optimal microenvironment for proliferation, migration, and differentiation. Furthermore, the nanofiber membrane structure is similar to the extracellular matrix, which is conducive to cell adhesion and promotes tissue regeneration. Compared to foam, the special structure of nanofiber membranes is more conducive to wound healing.

[0011] Therefore, this invention uses biodegradable wheat gluten protein as the main raw material, utilizing the special protein components (glutenin and prolamins) contained in wheat gluten protein. By controlling temperature and shear stirring, the gluten protein molecular chains are rearranged. Under high-speed shear conditions, the solution is fully exposed to oxygen in the air. Furthermore, the addition of alkali further oxidizes more sulfhydryl groups to form disulfide bonds, promoting the formation of intramolecular and intermolecular disulfide bond cross-linking networks. This invention achieves high water absorption and swelling properties in foams without adding chemical cross-linking agents, avoiding the adverse effects of using chemical cross-linking agents such as toxicity, cost, and long processing times. PVA has a significant impact on the appearance and mechanical properties of foams. Adding an appropriate amount of PVA can prepare wheat gluten protein foam with good appearance and high water absorption as the base layer of composite medical dressings. In addition, using biocompatible sodium alginate and PVA, which can improve the spinnability of sodium alginate, as raw materials, and adding carboxymethyl chitosan, sodium alginate / polyvinyl alcohol / carboxymethyl chitosan nanofiber membranes are prepared by electrospinning as the surface layer of composite medical dressings. The problem of achieving tight bonding between the surface nanofiber membrane and the base foam was solved by spraying a divalent metal cation aqueous solution onto the foam surface to create a physical cross-linking effect with sodium alginate, and by using a suction treatment. The suction treatment facilitates contact between the nanofibers and the foam; without it, the contact would be loose, preventing the full utilization of the metal ions. Only when the nanofibers are in close contact with the divalent metal cation aqueous solution on the foam surface does the exchange of divalent metal cations and alkali metal ions at the interface form a gel, which is beneficial for the adhesion between the nanofibers and the foam, resulting in a nanofiber / wheat gluten protein foam composite medical dressing.

[0012] The function of foam is to absorb large amounts of exudate, but its surface structure and function need to be improved. The function of nanofiber membrane is to come into direct contact with the wound. Relying on the antibacterial effects of sodium alginate and carboxymethyl chitosan, as well as the softness, comfort and porous structure of micro and nanofibers, it plays a positive role in wound treatment. However, its mechanical strength is low and its liquid absorption is limited, so it cannot be used alone. Therefore, the combination of nanofiber membrane and foam in composite medical dressings combines the advantages of both and is an ideal material for treating chronic wounds with large amounts of exudate, such as pressure ulcers and diabetic foot ulcers.

[0013] Further, in step (1), the mass of the wheat gluten protein powder accounts for 5% to 15% of the mass of the wheat gluten protein dispersion.

[0014] Further, in step (1), the plasticizer is one or more of glycerol, ethylene glycol and propylene glycol, and the mass of the plasticizer is 15% to 30% of the mass of wheat gluten protein powder.

[0015] Further, in step (1), the mass of the alkali is 0.5% to 3% of the mass of wheat gluten protein powder.

[0016] Further, in step (1), the alkali is selected from sodium hydroxide and / or potassium hydroxide.

[0017] Furthermore, in step (1), the heating temperature is 75–90°C.

[0018] Further, in step (1), the shearing and stirring is carried out mechanically at a speed of 8000-10000 r / min for 6-15 min.

[0019] Compared to three-dimensional foams, the appearance morphology is more difficult to control when preparing sheet foams, and defects such as ice crystal patterns, unevenness, and pinholes are prone to occur. The addition of PVA can significantly improve the uniformity of the foam, but excessive amounts will reduce the water absorption rate. Therefore, the mass of added PVA should be controlled to be 5% to 20% of the sum of the mass of PVA and wheat gluten protein powder.

[0020] In addition, PVA must be added after heating, shearing, and stirring are completed; otherwise, it will affect the cross-linking of disulfide bonds between molecules.

[0021] In one embodiment of the present invention, in step (1), wheat gluten protein powder is dispersed in water, plasticizer and alkali are added to obtain wheat gluten protein dispersion, the wheat gluten protein dispersion is heated at 75-90°C and mechanically stirred at a speed of 8000-10000 r / min for 6-15 min, polyvinyl alcohol is added and mixed evenly, the evenly mixed solution is transferred into a mold with a syringe and the surface is covered so that the solution completely fills the mold, and after freeze drying, round wheat gluten protein sheet foam is obtained.

[0022] Further, in step (2), the volume ratio of the sodium alginate aqueous solution, the polyvinyl alcohol aqueous solution, and the carboxymethyl chitosan aqueous solution is (5-8):(1-3):(1-2).

[0023] Further, in step (2), the mass of the sodium alginate accounts for 1% to 5% of the mass of the sodium alginate aqueous solution.

[0024] Further, in step (2), the mass of the polyvinyl alcohol accounts for 5% to 15% of the mass of the polyvinyl alcohol aqueous solution.

[0025] Further, in step (2), the mass of the carboxymethyl chitosan accounts for 2% to 10% of the mass of the carboxymethyl chitosan aqueous solution.

[0026] Furthermore, in step (3), the content of divalent metal cations in the aqueous solution of divalent metal cations is 2% to 5%.

[0027] Furthermore, in step (3), the divalent metal cation is selected from one or more of calcium ions, zinc ions and copper ions, with calcium ions being preferred in terms of cost and toxicity.

[0028] Furthermore, in step (3), wheat gluten protein sheet foam is placed on an electrospinning receiving plate with foam pores, and a suction device is installed behind the receiving plate. The suction treatment can promote the adhesion of nanofiber membrane to the foam.

[0029] Furthermore, the suction pressure of the suction treatment is 2 to 3.5 kPa.

[0030] Further, in step (3), the conditions for electrospinning are: spinning voltage of 10-20kV, spinning distance of 10-20cm, feeding rate of 0.001-0.003mm / s, needle type of 22G, and spinning time of 90-150min.

[0031] This invention also protects the nanofiber / wheat gluten protein foam composite medical dressing prepared by the above method.

[0032] The beneficial effects of this invention are:

[0033] This invention uses wheat gluten protein foam as the base layer and sodium alginate / polyvinyl alcohol / carboxymethyl chitosan nanofiber membrane as the surface layer (wound contact layer) to prepare a composite medical dressing. It has excellent liquid absorption rate, micro-nano porous structure and antibacterial properties, and is biodegradable, providing a novel composite medical dressing for the care of chronic wounds. Attached Figure Description

[0034] Figure 1 The image shows the appearance morphology of the wheat gluten protein sheet foam prepared in Example 1.

[0035] Figure 2 This is a scanning electron microscope image of the cross-section of the wheat gluten protein sheet foam prepared in Example 1.

[0036] Figure 3 This is a demonstration diagram showing the mechanical properties of the wheat gluten protein sheet foam prepared in Example 1 after absorbing water.

[0037] Figure 4 The image shows the appearance morphology of the wheat gluten protein sheet foam prepared in Example 2.

[0038] Figure 5 The image shows the appearance morphology of the wheat gluten protein sheet foam prepared in Comparative Example 1.

[0039] Figure 6 The image shows the appearance morphology of the wheat gluten protein sheet foam prepared in Comparative Example 2.

[0040] Figure 7 This is a demonstration diagram showing the mechanical properties of the wheat gluten protein sheet foam prepared in Comparative Example 2 after absorbing water.

[0041] Figure 8 The images show the state diagrams of wheat gluten protein solutions prepared under different temperature conditions in Comparative Example 2; where (a) represents 50℃, (b) represents 80℃, and (c) represents 110℃.

[0042] Figure 9 The image shows the appearance morphology of the wheat gluten protein sheet foam prepared in Comparative Example 3.

[0043] Figure 10 The images show the state diagrams of wheat gluten protein solutions prepared under different stirring time conditions in Comparative Example 3; where (a) represents 4 min, (b) represents 10 min, and (c) represents 20 min.

[0044] Figure 11 This is a macroscopic morphology diagram of the surface nanofiber membrane prepared in Example 3.

[0045] Figure 12 This is a scanning electron microscope image of the surface nanofiber membrane prepared in Example 3.

[0046] Figure 13 The image shows the cross-sectional appearance of the nanofiber / wheat gluten protein foam composite medical dressing prepared in Example 3.

[0047] Figure 14 The image shows a scanning electron microscope (SEM) image of the cross-section of the nanofiber / wheat gluten protein foam composite medical dressing prepared in Example 3.

[0048] Figure 15 The images show the appearance morphology of the nanofiber / wheat gluten protein foam composite medical dressing prepared in Comparative Example 4; where (a) is a top view and (b) is a cross-sectional view.

[0049] Figure 16 This is a cross-sectional view of the nanofiber / wheat gluten protein foam composite medical dressing prepared in Comparative Example 5.

[0050] Figure 17 The image shows a scanning electron microscope (SEM) image of the cross-section of the nanofiber / wheat gluten protein foam composite medical dressing prepared in Comparative Example 5. Detailed Implementation

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0052] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0053] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used are commercially available.

[0054] The methods for testing the mechanical properties and liquid absorption properties of the following embodiments and comparative examples are as follows:

[0055] Mechanical property testing: Tensile mechanical tests were conducted using a YG028 universal testing machine, referring to GB / T 3923.1-2013 Textiles - Tensile Properties of Fabrics - Part 1: Determination of Breaking Strength and Elongation at Break (Strip Method).

[0056] Liquid absorption performance test: The liquid absorption performance test was conducted in accordance with YY / T0471.1—2004 Test methods for contact wound dressings Part 1: Liquid absorbency.

[0057] Example 1: Wheat gluten protein sheet foam

[0058] A method for preparing wheat gluten protein sheet foam includes the following steps:

[0059] 14g of wheat gluten protein powder was dispersed in 80mL of deionized water and stirred on a magnetic stirrer. 3.5g of glycerol was added, and the mixture was continuously stirred. 6mL of 1mol / L NaOH aqueous solution was added, and the mixture was stirred until homogeneous to obtain a wheat gluten protein dispersion. The oil bath temperature was kept constant at 80℃. The dispersion was placed in a silicone oil bath and heated and stirred for 10min at a stirring speed of 9000r / min. The dispersion was removed from the oil bath and cooled to room temperature in a cold water bath. A PVA aqueous solution containing 1g of PVA (the mass of PVA accounts for 6.7% of the sum of the mass of PVA and wheat gluten protein powder) was added to prepare a 100mL mixed solution. After stirring for 1h, the mixed solution was transferred to a circular mold with a diameter of 4.8cm and a depth of 2mm using a syringe. The mold was then covered to completely fill the mold with the solution. The mold containing the mixed solution was placed in a freeze dryer at -60℃ for 8h and then dried for 24h to obtain wheat gluten protein sheet foam.

[0060] Figure 1 The image shows the appearance morphology of the wheat gluten protein sheet foam prepared in Example 1. Figure 2 This is a scanning electron microscope (SEM) image of the cross-section of the wheat gluten protein sheet-like foam prepared in Example 1. Figure 2 The porous cross-linked structure of the foam can be seen in the image. Figure 3 This is a demonstration image showing the mechanical properties of the wheat gluten protein sheet foam prepared in Example 1 after water absorption. Figure 3 As can be seen, the foam exhibits good mechanical properties after absorbing liquid; it does not break or break when picked up with tweezers. Tests showed that the wheat gluten protein sheet foam prepared in Example 1 had a liquid absorption rate of 676.54% and a tensile strength of 960.42 kPa.

[0061] Example 2: Wheat gluten protein sheet foam

[0062] A method for preparing wheat gluten protein sheet foam includes the following steps:

[0063] 14g of wheat gluten protein powder was dispersed in 80mL of deionized water and stirred on a magnetic stirrer. 3.5g of glycerol was added, and the mixture was stirred continuously. 6mL of 1mol / L NaOH aqueous solution was added, and the mixture was stirred until homogeneous to obtain a wheat gluten protein dispersion. The oil bath temperature was kept constant at 80℃. The dispersion was placed in a silicone oil bath and heated and stirred for 10min at a stirring speed of 9000r / min. The dispersion was removed from the oil bath and cooled to room temperature in a cold water bath. A PVA aqueous solution containing 3g of PVA (the mass of PVA accounts for 17.6% of the sum of the mass of PVA and wheat gluten protein powder) was added to prepare a 100mL mixed solution. After stirring for 1h, the mixed solution was transferred to a circular mold with a diameter of 4.8cm and a depth of 2mm using a syringe. The mold was covered to completely fill the mold with the solution. The mold containing the mixed solution was placed in a freeze dryer at -60℃ for 8h and then dried for 24h to obtain wheat gluten protein sheet foam.

[0064] Figure 4The image shows the appearance morphology of the wheat gluten protein sheet foam prepared in Example 2. Comparing it with the appearance morphology of Example 1, it can be seen that when the PVA content is increased to 3g (17.6%), the foam appearance morphology is not significantly different, and the surface and overall uniformity are good. However, testing the mechanical properties of the foam reveals that the amount of PVA added has a significant impact on the liquid absorption rate and mechanical properties of the wheat gluten protein sheet foam. The tensile strength of the wheat gluten protein sheet foam increases to 1175.65 kPa, but the liquid absorption rate decreases to 352.5%. Macroscopically, more PVA results in greater foam strength but lower water absorption. Adding an appropriate amount of PVA improves the uniformity of the foam morphology while ensuring a certain level of liquid absorption.

[0065] Comparative Example 1: Wheat gluten protein sheet foam

[0066] A method for preparing wheat gluten protein sheet foam includes the following steps:

[0067] 14g of wheat gluten protein powder was dispersed in 80mL of deionized water and stirred on a magnetic stirrer. 3.5g of glycerol was added, and the mixture was stirred continuously. 6mL of 1mol / L NaOH aqueous solution was added, and the mixture was stirred until homogeneous to obtain 100mL of wheat gluten protein dispersion. The oil bath temperature was maintained at 80℃. The dispersion was placed in a silicone oil bath and heated and stirred for 10min at a stirring speed of 9000r / min. The dispersion was removed from the oil bath and cooled to room temperature in a cold water bath. The dispersion was then transferred to a circular mold with a diameter of 4.8cm and a depth of 2mm using a syringe, and the mold was covered to completely fill it with the dispersion. The mold containing the dispersion was placed in a freeze dryer at -60℃ for 8h and then dried for 24h to obtain wheat gluten protein sheet foam.

[0068] Figure 5 The image shows the apparent morphology of the wheat gluten protein sheet-like foam prepared in Comparative Example 1. Figure 5 As can be seen, without the addition of PVA, the wheat gluten protein flake foam is yellow, has surface cracks, and poor overall uniformity, basically failing to meet the requirements for use and testing. This contrasts with the white, smooth, and uniform wheat gluten protein flake foam prepared in Example 1. Figure 1 The difference is significant, which demonstrates the role of an appropriate amount of PVA in the uniformity of foam molding.

[0069] Comparative Example 2: Wheat gluten protein sheet foam

[0070] A method for preparing wheat gluten protein sheet foam includes the following steps:

[0071] 14g of wheat gluten protein powder was dispersed in 80mL of deionized water and stirred on a magnetic stirrer. 3.5g of glycerol was added, and the mixture was stirred continuously. 6mL of 1mol / L NaOH aqueous solution was added, and the mixture was stirred until homogeneous to obtain 100mL of wheat gluten protein dispersion. The oil bath temperature was maintained at 110℃. The dispersion was placed in a silicone oil bath and heated and stirred for 10min at a stirring speed of 9000r / min. The dispersion was removed from the oil bath and cooled to room temperature in a cold water bath. The dispersion was then transferred to a circular mold with a diameter of 4.8cm and a depth of 2mm using a syringe, and the mold was covered to completely fill the mold. The mold containing the mixed solution was placed in a freeze dryer at -60℃ for 8h and then dried for 24h to obtain wheat gluten protein sheet foam.

[0072] Figure 6 The image shows the appearance morphology of the wheat gluten protein sheet foam prepared in Comparative Example 2.

[0073] Figure 7 This is a demonstration image showing the mechanical properties of the wheat gluten protein sheet foam prepared in Comparative Example 2 after water absorption. Figure 7 As can be seen, foam disperses easily in water.

[0074] Figure 8 The images show the state diagrams of wheat gluten protein solutions prepared under different temperature conditions in Comparative Example 2; where (a) represents 50℃, (b) represents 80℃, and (c) represents 110℃. Figure 8 As can be seen, wheat gluten protein solutions prepared under different temperature conditions exhibit significant differences. At excessively low temperatures, the solution viscosity is low; at moderate temperatures, the solution is semi-gel-like; and at excessively high temperatures, the color changes to brown and the viscosity also decreases. Figure 7 As shown, foam with low viscosity is not only unevenly formed, but also prone to cracking or dispersing when exposed to water.

[0075] Comparing the properties of the wheat gluten protein sheet foams prepared in Comparative Example 1 and Comparative Example 2, it can be seen that the heating temperature has a significant impact on the appearance morphology and mechanical properties of the prepared wheat gluten protein sheet foams.

[0076] Comparative Example 3: Wheat gluten protein sheet foam

[0077] A method for preparing wheat gluten protein sheet foam includes the following steps:

[0078] 14g of wheat gluten protein powder was dispersed in 80mL of deionized water and stirred on a magnetic stirrer. 3.5g of glycerol was added, and the mixture was stirred continuously. 6mL of 1mol / L NaOH aqueous solution was added, and the mixture was stirred until homogeneous to obtain 100mL of wheat gluten protein dispersion. The oil bath temperature was maintained at 80℃. The dispersion was placed in a silicone oil bath and heated and stirred for 4min at a stirring speed of 9000r / min. The dispersion was removed from the oil bath and cooled to room temperature in a cold water bath. The dispersion was then transferred to a circular mold with a diameter of 4.8cm and a depth of 2mm using a syringe, and the mold was covered to completely fill the mold. The mold containing the mixed solution was placed in a freeze dryer at -60℃ for 8h and then dried for 24h to obtain wheat gluten protein sheet foam.

[0079] Figure 9 The image shows the appearance of the wheat gluten protein sheet foam prepared in Comparative Example 3. The foam is brittle and has poor uniformity, failing to meet the requirements for use and testing.

[0080] Figure 10 The images show the state diagrams of wheat gluten protein solutions prepared under different stirring times for Comparative Example 3; where (a) represents 4 min, (b) represents 10 min, and (c) represents 20 min. Figure 10 As can be seen, there are significant differences in the wheat gluten protein solutions prepared under different stirring time conditions. Short stirring-shear time results in low solution viscosity; moderate stirring-shear time results in a semi-gel-like solution; and excessive stirring-shear time results in excessively high solution viscosity, which is jelly-like and cannot be molded.

[0081] Comparing the wheat gluten flake foams prepared in Comparative Example 1 and Comparative Example 3, it can be seen that stirring time has a significant impact on the appearance morphology and mechanical properties of wheat gluten flake foams. Controlling appropriate shear time and temperature is crucial for wheat gluten to produce suitable intermolecular interactions and cross-linking, which is key to forming foams with good mechanical and liquid absorption properties.

[0082] Example 3: Nanofiber / wheat gluten protein foam composite medical dressing

[0083] A method for preparing a nanofiber / wheat gluten protein foam composite medical dressing includes the following steps:

[0084] (1) Disperse 14g of wheat gluten protein powder in 80mL of deionized water, stir on a magnetic stirrer, add 3.5g of glycerol, continue to disperse and stir, add 6mL of 1mol / L NaOH aqueous solution, and stir evenly to obtain wheat gluten protein dispersion. The oil bath temperature is kept constant at 80℃. Place the dispersion in a silicone oil bath and heat and stir for 10min at a stirring speed of 9000r / min. Remove the dispersion from the oil bath and cool it to room temperature in a cold water bath. Add PVA aqueous solution containing 1g of PVA to prepare 100mL of mixed solution. After stirring and mixing for 1h, transfer the mixed solution to a circular mold with a diameter of 4.8cm and a depth of 2mm using a syringe, and cover the surface to completely fill the mold with the solution. Place the mold containing the mixed solution in a freeze dryer at -60℃ and freeze for 8h, then dry for 24h to obtain wheat gluten protein sheet foam.

[0085] (2) Dissolve 0.3g sodium alginate in 9.7mL of deionized water and stir at room temperature for 3h to obtain sodium alginate aqueous solution; dissolve 1g PVA in 9mL of deionized water and heat and stir continuously for 2h to obtain polyvinyl alcohol aqueous solution; dissolve 1g CMCS in 9mL of deionized water and stir at room temperature for 5h to obtain carboxymethyl chitosan aqueous solution; mix sodium alginate aqueous solution, polyvinyl alcohol aqueous solution and carboxymethyl chitosan aqueous solution in a volume ratio of 7:2:1 and stir for 3h to obtain electrospinning solution.

[0086] (3) Wheat gluten protein sheet foam was placed on an electrospinning receiving plate with foam pores. A suction pipe was connected to the back of the receiving plate. A 2% CaCl2 solution was sprayed onto the wheat gluten protein sheet foam using a nano spray bottle, spraying three times at a distance of 8 cm from the sample. The electrospinning solution was transferred to a syringe for electrospinning. The electrospinning conditions were: 22G needle, 10kV spinning voltage, 0.002mm / s feeding rate, and 20cm spinning distance. During electrospinning, the other side of the wheat gluten protein foam was subjected to suction treatment at a suction pressure of 3.5kPa. After 2 hours of electrospinning, the foam was removed from the receiver and allowed to air dry to obtain a nanofiber / wheat gluten protein foam composite medical dressing.

[0087] Figure 11 This is a macroscopic morphology image of the surface nanofiber membrane prepared in Example 3. Figure 12 This is a scanning electron microscope (SEM) image of the surface nanofiber membrane prepared in Example 3. Figure 11 and 12 As can be seen, the nanofiber membrane has a smooth and uniform macroscopic surface, and a random interlacing of fibers at the microscopic level. It has pores, good fiber morphology, and an average diameter of about 216 nm.

[0088] Figure 13This image shows the cross-sectional appearance of the nanofiber / wheat gluten protein foam composite medical dressing prepared in Example 3. Figure 14 This is a scanning electron microscope (SEM) image of the cross-section of the nanofiber / wheat gluten protein foam composite medical dressing prepared in Example 3. Figure 13 and 14 As can be seen, the surface nanofiber membrane is tightly bonded to the base foam.

[0089] The nanofiber / wheat gluten protein foam composite medical dressing prepared in Example 3 was tested and found to have a liquid absorption rate of 689.5% and a tensile strength of 963.91 kPa.

[0090] Comparative Example: 4-nanofiber / wheat gluten protein foam composite medical dressing

[0091] A method for preparing a nanofiber / wheat gluten protein foam composite medical dressing includes the following steps:

[0092] (1) Disperse 14g of wheat gluten protein powder in 80mL of deionized water, stir on a magnetic stirrer, add 3.5g of glycerol, continue to disperse and stir, add 6mL of 1mol / L NaOH aqueous solution, and stir evenly to obtain wheat gluten protein dispersion. The oil bath temperature is kept constant at 80℃. Place the dispersion in a silicone oil bath and heat and stir for 10min at a stirring speed of 9000r / min. Remove the dispersion from the oil bath and cool it to room temperature in a cold water bath. Add PVA aqueous solution containing 1g of PVA to prepare 100mL of mixed solution. After stirring and mixing for 1h, transfer the mixed solution to a circular mold with a diameter of 4.8cm and a depth of 2mm using a syringe, and cover the surface to completely fill the mold with the solution. Place the mold containing the mixed solution in a freeze dryer at -60℃ and freeze for 8h, then dry for 24h to obtain wheat gluten protein sheet foam.

[0093] (2) Dissolve 0.3g sodium alginate in 9.7mL of deionized water and stir at room temperature for 3h to obtain sodium alginate aqueous solution; dissolve 1g PVA in 9mL of deionized water and heat and stir continuously for 2h to obtain polyvinyl alcohol aqueous solution; dissolve 1g CMCS in 9mL of deionized water and stir at room temperature for 5h to obtain carboxymethyl chitosan aqueous solution; mix sodium alginate aqueous solution, polyvinyl alcohol aqueous solution and carboxymethyl chitosan aqueous solution in a volume ratio of 7:2:1 and stir for 3h to obtain electrospinning solution.

[0094] (3) Place wheat gluten protein sheet foam on an electrospinning receiving plate with foam pores, spray a 2% CaCl2 solution onto the wheat gluten protein sheet foam, and spray three times at a distance of 8 cm from the sample using a nano spray bottle; transfer the electrospinning solution to a syringe for electrospinning. The electrospinning conditions are: needle type 22G, spinning voltage 10kV, feeding rate 0.002mm / s, spinning distance 20cm. After 2 hours of electrospinning, remove the foam from the receiver and let it air dry to obtain nanofiber / wheat gluten protein foam composite medical dressing.

[0095] Figure 15 The images show the morphology of the nanofiber / wheat gluten protein foam composite medical dressing prepared in Comparative Example 4; where (a) is a top view and (b) is a cross-sectional view. Figure 15 As can be seen from the example, compared with Example 2, when only 2% CaCl2 solution was sprayed, some parts of the nanofiber membrane and foam were not tightly bonded. This is because when the suction device is not available, the nanofibers cannot fully contact the foam surface when they reach the receiving device (because theoretically the foam surface is not completely on a vertical plane), resulting in the sodium ions and calcium ions in the sodium alginate not undergoing ion exchange and forming a gel.

[0096] Comparative Example: 5-nano fiber / wheat gluten protein foam composite medical dressing

[0097] A method for preparing a nanofiber / wheat gluten protein foam composite medical dressing includes the following steps:

[0098] (1) Disperse 14g of wheat gluten protein powder in 80mL of deionized water, stir on a magnetic stirrer, add 3.5g of glycerol, continue to disperse and stir, add 6mL of 1mol / L NaOH aqueous solution, and stir evenly to obtain wheat gluten protein dispersion. The oil bath temperature is kept constant at 80℃. Place the dispersion in a silicone oil bath and heat and stir for 10min at a stirring speed of 9000r / min. Remove the dispersion from the oil bath and cool it to room temperature in a cold water bath. Add PVA aqueous solution containing 1g of PVA to prepare 100mL of mixed solution. After stirring and mixing for 1h, transfer the mixed solution to a circular mold with a diameter of 4.8cm and a depth of 2mm using a syringe, and cover the surface to completely fill the mold with the solution. Place the mold containing the mixed solution in a freeze dryer at -60℃ and freeze for 8h, then dry for 24h to obtain wheat gluten protein sheet foam.

[0099] (2) Dissolve 0.3g sodium alginate in 9.7mL of deionized water and stir at room temperature for 3h to obtain sodium alginate aqueous solution; dissolve 1g PVA in 9mL of deionized water and heat and stir continuously for 2h to obtain polyvinyl alcohol aqueous solution; dissolve 1g CMCS in 9mL of deionized water and stir at room temperature for 5h to obtain carboxymethyl chitosan aqueous solution; mix sodium alginate aqueous solution, polyvinyl alcohol aqueous solution and carboxymethyl chitosan aqueous solution in a volume ratio of 7:2:1 and stir for 3h to obtain electrospinning solution.

[0100] (3) Wheat gluten protein sheet foam was placed on an electrospinning receiving plate with foam pores. The electrospinning solution was transferred to a syringe for electrospinning. The electrospinning conditions were: 22G needle, 10kV spinning voltage, 0.002mm / s feeding rate, and 20cm spinning distance. During electrospinning, the other side of the wheat gluten protein foam was subjected to suction treatment at a pressure of 3kPa. After 2 hours of electrospinning, the foam was removed from the receiver and allowed to air dry to obtain a nanofiber / wheat gluten protein foam composite medical dressing.

[0101] Figure 16 This is a cross-sectional view of the nanofiber / wheat gluten protein foam composite medical dressing prepared in Comparative Example 5. Figure 17 The image shows a scanning electron microscope (SEM) image of the cross-section of the nanofiber / wheat gluten protein foam composite medical dressing prepared in Comparative Example 5. Figure 16 and 17 As can be seen, there is a clear delamination phenomenon between the nanofiber membrane and the wheat gluten protein foam. This is because air suction alone is not enough to create a strong bonding interface between the nanofiber membrane and the foam. Comparative Examples 4 and 5 demonstrate that only the synergistic effect of air suction and the surface calcium chloride solution can achieve a tight bonding between the surface and base layers of the composite medical dressing.

[0102] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art should understand that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a nanofiber / wheat gluten protein foam composite medical dressing, characterized in that, Includes the following steps: (1) Wheat gluten protein powder, plasticizer and alkali are dispersed in water to obtain wheat gluten protein dispersion. The wheat gluten protein dispersion is heated and sheared and stirred. Then polyvinyl alcohol is added and mixed evenly. After freeze drying, wheat gluten protein foam is obtained. (2) Mix sodium alginate aqueous solution, polyvinyl alcohol aqueous solution and carboxymethyl chitosan aqueous solution to obtain electrospinning solution; (3) Coat one side of the wheat gluten protein foam obtained in step (1) with a divalent metal cation aqueous solution and perform electrospinning using the electrospinning solution obtained in step (2). At the same time, perform air suction treatment on the other side of the wheat gluten protein foam to obtain the nanofiber / wheat gluten protein foam composite medical dressing.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass of the wheat gluten protein powder accounts for 5% to 15% of the mass of the wheat gluten protein dispersion.

3. The preparation method according to claim 1, characterized in that, In step (1), the plasticizer is one or more of glycerol, ethylene glycol and propylene glycol, and the mass of the plasticizer is 15% to 30% of the mass of wheat gluten protein powder.

4. The preparation method according to claim 1, characterized in that, In step (1), the heating temperature is 75-90°C.

5. The preparation method according to claim 1, characterized in that, In step (1), the shearing and stirring is carried out mechanically at a speed of 8000-10000 r / min for 6-15 min.

6. The preparation method according to claim 1, characterized in that, In step (1), the mass of the polyvinyl alcohol accounts for 5% to 20% of the sum of the mass of polyvinyl alcohol and wheat gluten protein powder.

7. The preparation method according to claim 1, characterized in that, In step (2), the volume ratio of the sodium alginate aqueous solution, the polyvinyl alcohol aqueous solution, and the carboxymethyl chitosan aqueous solution is (5-8):(1-3):(1-2).

8. The preparation method according to claim 1, characterized in that, In step (3), the suction pressure of the suction treatment is 2 to 3.5 kPa.

9. The preparation method according to claim 1, characterized in that, In step (3), the conditions for electrospinning are a spinning voltage of 10-20 kV, a spinning distance of 10-20 cm, and a feeding rate of 0.001-0.003 mm / s.

10. A nanofiber / wheat gluten protein foam composite medical dressing prepared by the method according to any one of claims 1 to 9.

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