Self-oxygen-supply dressing for oxygen therapy healing of diabetic wound and preparation method of self-oxygen-supply dressing

Abstract

A self-oxygen-supply dressing for oxygen therapy healing of diabetic wounds comprises an all-cotton spunlace non-woven fabric, a flash evaporation non-woven fabric, a conducting layer and self-oxygen-supply hydrogel which are sequentially arranged from top to bottom, the conducting layer is composed of a plurality of conducting individuals, and each conducting individual is of a hollow honeycomb structure. All conduction individuals are clamped between the flash-evaporation-method non-woven fabric and the self-oxygen-supply hydrogel, the self-oxygen-supply hydrogel is of a three-dimensional network structure and contains water and Fe3O4-CaO2 nanoparticles, the moisture absorption capacity of the all-cotton spunlace non-woven fabric is larger than that of the flash-evaporation-method non-woven fabric, and the self-oxygen-supply hydrogel is of a three-dimensional network structure and contains Fe3O4-CaO2 nanoparticles. And the conduction individuals absorb water seeping from the top surface of the oxygen supply hydrogel through capillary action. According to the design, dissolved oxygen can be automatically generated, oxygen is supplied to facilitate angiogenesis, humidity balance can be carried out on a wound, the magnetic therapy effect can be provided, and the wound healing effect is good.

Description

Technical Field

[0001] The invention relates to a dressing for healing diabetic wounds, belongs to the field of functional nonwoven fabrics, and in particular relates to a self-oxygenating dressing for oxygen therapy healing of diabetic wounds and a preparation method thereof. Background Art

[0002] In recent years, the prevalence of diabetes in my country has shown a clear upward trend. Diabetes and its complications, as a chronic disease, have gradually affected all aspects of people's lives.

[0003] Diabetic foot ulcer is one of the most serious chronic complications of diabetes and the main cause of non-traumatic amputation in diabetes. 20% of diabetic foot patients need amputation treatment, which not only greatly reduces the quality of life of diabetic foot patients, but also seriously threatens the lives of patients. The overall mortality rate of diabetic foot ulcer within 5 years of onset is as high as 50%.

[0004] The invention patent application with application number 202110904074.8 and application date August 6, 2021 discloses a method for preparing an extracellular matrix-mimicking hydrogel dressing for diabetic foot ulcers, which first disperses polydopamine nanoparticles loaded with deferoxamine mesylate in a modified human-like collagen solution, then mixes it with a hyaluronic acid solution grafted with epigallocatechin gallate dimer, and then adds a tyrosinase solution to obtain an extracellular matrix-mimicking hydrogel dressing. This design provides an extracellular matrix-mimicking hydrogel dressing (which contains polydopamine nanoparticles and hyaluronic acid grafted with epigallocatechin gallate dimer) in the hope of solving the problems of impaired angiogenesis and long-term chronic inflammation in diabetic foot ulcer wounds, but the design still has the following defects: First, the design focuses on providing a special extracellular matrix to eliminate inflammation and help angiogenesis, rather than focusing on overcoming the intrinsic defects of angiogenesis and solving the real obstacles to angiogenesis, such as hypoxia, from the internal causes of wound difficulty in healing; Secondly, the design ignores the effect of wound moisture on healing and lacks moisture balance control technology.

[0005] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the application, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects and problems existing in the prior art, such as failure to supply oxygen to facilitate angiogenesis, inability to achieve humidity balance, and poor wound healing effect, and to provide a self-oxygenating dressing for oxygen therapy healing of diabetic wounds, which supplies oxygen to facilitate angiogenesis, can achieve humidity balance, and has better wound healing effect, and a preparation method thereof.

[0007] To achieve the above objectives, the technical solution of the present invention is: a self-oxygenating dressing for oxygen therapy healing of diabetic wounds, the self-oxygenating dressing comprising a cotton spunlace nonwoven fabric, a flash-steamed nonwoven fabric, a conductive layer, and a self-oxygenating hydrogel arranged in sequence from top to bottom, and the conductive layer comprises a plurality of conductive individuals arranged along the top surface of the self-oxygenating hydrogel, and the conductive individuals are hollow honeycomb structures; The top surface of the flash-steamed nonwoven fabric is connected to the bottom surface of the all-cotton spunlace nonwoven fabric, and the bottom surface of the flash-steamed nonwoven fabric is connected to the top surface of the self-oxygenating hydrogel, and all the conductive entities are sandwiched between the flash-steamed nonwoven fabric and the self-oxygenating hydrogel; The self-oxygenating hydrogel is a three-dimensional network structure, which contains water and Fe3O4-CaO2 nanoparticles; The moisture absorption capacity of the all-cotton spunlace nonwoven fabric is greater than that of the flash-steamed nonwoven fabric, and the conductive individual absorbs the water seeping from the top surface of the self-oxygenating hydrogel through capillary action.

[0008] The top surface of the flash-steamed nonwoven fabric is connected to the bottom surface of the all-cotton spunlace nonwoven fabric, which means that the periphery of the flash-steamed nonwoven fabric is connected to the periphery of the all-cotton spunlace nonwoven fabric through a waterproof adhesive tape, and at the same time, the middle part of the top surface of the flash-steamed nonwoven fabric is connected to the middle part of the bottom surface of the all-cotton spunlace nonwoven fabric through multiple bonding points.

[0009] The self-oxygenating hydrogel is a three-dimensional network structure, which means that the self-oxygenating hydrogel is formed by the three-dimensional network structure generated by PVA and the three-dimensional network structure generated by CMCS interlaced with each other.

[0010] The Fe3O4-CaO2 nanoparticles refer to composite particles formed by physically binding Fe3O4 and CaO2 by HA.

[0011] A method for preparing the above-mentioned self-oxygenating dressing for oxygen therapy healing of diabetic wounds, the preparation method comprising the following steps: The first step: firstly, PVA and water are used to prepare a paste-like PVA solution, in which the mass percentage concentration of PVA is 8%-10%, and then CMCS and water are used to prepare a CMCS solution, in which the mass percentage concentration of CMCS is 5%-8%, and then the PVA solution and the CMCS solution are mixed to obtain a primary mixed solution, in which the mass proportion of the PVA solution in the primary mixed solution is 30%-50%, and then Fe3O4-CaO2 nanoparticles are added to the primary mixed solution and uniformly dispersed to obtain a secondary mixed solution, in which the mass of the Fe3O4-CaO2 nanoparticles is 1%-5% of the primary mixed solution; Step 2: first turn over the flash nonwoven fabric, then place an annular mold on the top surface of the flash nonwoven fabric, then place a plurality of conductive individuals on the flash nonwoven fabric in the area within the mold, then inject the secondary mixed liquid into the mold, then seal the mold after the injection, and then freeze and thaw the flash nonwoven fabric, the conductive individuals, the secondary mixed liquid, and the mold together, repeat this operation 6-8 times, then release the mold seal, and remove the mold, at this time, the secondary mixed liquid has become a self-oxygenating hydrogel, and the self-oxygenating hydrogel, the flash nonwoven fabric, and all the conductive individuals are connected into an integrated structure; Step 3: First, flip the flash-steamed nonwoven fabric together with the conductive individual and self-oxygenating hydrogel back to their original position, and then connect the top surface of the flash-steamed nonwoven fabric to the bottom surface of the all-cotton spunlace nonwoven fabric to obtain the above-mentioned self-oxygenating dressing for oxygen therapy healing of diabetic wounds.

[0012] In the second step, the conductive individual is prepared according to the following steps: first, fresh lotus leaf stems are picked, then purified, and then quickly frozen with liquid nitrogen, and then the lotus leaf stems after quick freezing are sliced, and then the slices are placed in a vacuum freeze dryer for freeze drying, and then the freeze-dried slices are placed in a tubular furnace, and in a nitrogen atmosphere, the temperature is raised from room temperature to 180°C-220°C, and kept warm for 0.8-1.2h to obtain a precursor sheet, and then the precursor sheet is evenly mixed with an alkaline solution, and then the mixture is dried, and then the residue after drying is placed in a tubular furnace, heated to 380°C-420°C, and roasted for 0.8-1.2h, and then naturally cooled to ambient temperature to obtain a conductive individual.

[0013] After naturally cooling to ambient temperature, the substrate is first immersed in HCl solution, then rinsed with deionized water, and then the pH value is tested, and the cycle is repeated until the measured pH value is 7-7.3, and then dried to obtain a conductive individual.

[0014] In the second step, the freezing temperature is -20°C to -30°C, and the thawing is performed at room temperature.

[0015] In the first step, the preparation steps of the PVA solution are: first add PVA to a beaker, then add water, then seal the beaker, and then heat them in a water bath until they are at 60°C, then keep them warm until the PVA is obviously swollen, then heat them to 90°C, and then magnetically stir the beaker at the temperature until the PVA is fully dissolved to obtain a paste-like PVA solution; In the first step, the CMCS solution is prepared by first adding powdered CMCS into a beaker, then adding water, then sealing the beaker, and then magnetically stirring the beaker until the CMCS is fully dissolved to obtain a CMCS solution.

[0016] In the third step, the all-cotton spunlace nonwoven fabric is a grafted all-cotton spunlace nonwoven fabric, and its preparation steps are: first immerse the all-cotton spunlace nonwoven fabric in an isopropanol solution, then seal it and place it in a magnetic stirrer, set the temperature to 35-45°C, keep it at a constant temperature for 30-50 minutes, then open the seal, add sodium hydroxide solution, then seal it, heat it to 40-50°C, keep it warm and stir it for 40-60 minutes, and then let it stand for 0.8-1.2 hours to allow the cotton fiber to react with the sodium hydroxide. The sodium cellulose is obtained by fully reacting, and the temperature remains unchanged during the reaction. The seal is then opened, and a mixture of chloroacetic acid and isopropanol is added, and the seal is then re-adjusted to 20-25°C and reacted for 7-9 hours to obtain modified cotton fibers. The modified cotton fibers are then taken out and the pH value is adjusted to 7-7.3 with glacial acetic acid, and then washed three times with 80% ethanol and anhydrous ethanol, and then dried to obtain a grafted all-cotton spunlace nonwoven fabric. The grafted all-cotton spunlace nonwoven fabric has a moisture absorption capacity greater than that of the above-mentioned all-cotton spunlace nonwoven fabric.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. A self-oxygenating dressing for oxygen therapy healing of diabetic wounds and a preparation method thereof, comprising a cotton spunlace nonwoven fabric, a flash-steamed nonwoven fabric, a conductive layer, and a self-oxygenating hydrogel arranged in sequence from top to bottom, wherein the top surface of the flash-steamed nonwoven fabric is connected to the bottom surface of the cotton spunlace nonwoven fabric, the bottom surface of the flash-steamed nonwoven fabric is connected to the top surface of the self-oxygenating hydrogel, and all conductive entities are sandwiched between the flash-steamed nonwoven fabric and the self-oxygenating hydrogel, wherein the self-oxygenating hydrogel The hydrogel is a three-dimensional network structure, which contains water and Fe3O4-CaO2 nanoparticles. The conductive layer includes a plurality of conductive individuals arranged along the top surface of the self-oxygenating hydrogel. The conductive individuals are hollow honeycomb structures. The moisture absorption capacity of the cotton spunlace nonwoven fabric is greater than that of the flash-steamed nonwoven fabric, and the conductive individuals absorb the water seeping from the top surface of the self-oxygenating hydrogel through capillary action. When used, the bottom surface of the self-oxygenating hydrogel is in direct contact with the wound. The advantages of this design include: First point: The interior of the self-oxygenating hydrogel contains water and Fe3O4-CaO2 nanoparticles. Fe3O4-CaO2 nanoparticles can provide Fe3O4 and CaO2. Calcium peroxide reacts with water to generate hydrogen peroxide and calcium hydroxide. Hydrogen peroxide decomposes to produce oxygen. Ferroferric oxide can catalyze the process of hydrogen peroxide producing oxygen, as shown below: CaO2+2H2O → H2O2+Ca(OH)2; H2O2+2Fe3+ → 2Fe2++O2+2H+; Fe2++ H2O2 → Fe3++(OH)-+OH•; As a result, the decomposition of free hydrogen peroxide becomes more active and faster in the hydrogel network, minimizing the possibility of releasing free hydrogen peroxide from the microsystem. It can not only generate oxygen autonomously, but also dissolve oxygen in water through catalytic reactions. The final product is dissolved oxygen, which can penetrate into the wound through liquid exchange, thus penetrating into the deep layer of the wound of diabetic patients (dissolved oxygen can penetrate human skin with a thickness greater than 700μm, while local gaseous oxygen can only penetrate the dermis layer of 300μm), providing an oxygen-rich environment for wound recovery, directly facilitating angiogenesis and improving wound healing. Second point: The internal structure of the hydrogel is a three-dimensional network structure with strong water retention capacity. On the one hand, it can support the self-oxygenation reaction and ensure the smooth generation of dissolved oxygen. On the other hand, it can absorb the tissue fluid exuded from the wound, which can be used to supplement the raw materials for the generation of dissolved oxygen and improve the oxygen supply efficiency. After absorption saturation, the water can be discharged from the top of the hydrogel in a free state, and then absorbed by the conducting individual through capillary action. Then, through the connection point between the internal pipeline of the conducting individual and the flash-steamed nonwoven fabric, the flash-steamed nonwoven fabric and the cotton spunlace nonwoven fabric are connected. The unidirectional moisture-conducting structure constructed by the difference in moisture absorption capacity is transported all the way to the topmost cotton spunlace nonwoven fabric, thereby constructing a plant transpiration model with the flash nonwoven fabric as the core, so that when the wound tissue fluid is small, the water content of the hydrogel is maintained to ensure the humidity of wound healing, avoid the wound surface from drying out, and cause wound adhesion (such as local oxygen therapy in the prior art), so as to facilitate wound healing. When the tissue fluid is large, it is quickly converted into moisture for drainage to avoid excessive humidity and hinder wound healing, thereby controlling the overall balance of the wound moisture environment and exerting zero pressure on the wound. Third point: Fe3O4 in Fe3O4-CaO2 nanoparticles has its own magnetism, which can provide a magnetic field for chronic wounds, allowing magnetic lines to penetrate deep into human tissues, accelerate cell resurrection and renewal, enhance the vitality of blood cells, purify blood, improve microcirculation, and enhance wound healing effects; Therefore, the present invention can not only autonomously generate dissolved oxygen and supply oxygen to facilitate angiogenesis, but also balance the moisture of the wound and provide magnetic therapy, thereby achieving better wound healing effect.

[0018] 2. In the self-oxygenating dressing for oxygen therapy and healing of diabetic wounds of the present invention and the preparation method thereof, when making the conductive individual, the fresh lotus leaf stem is first subjected to quick freezing, slicing, and freeze-drying treatment in sequence, and then protected by nitrogen atmosphere in a tubular furnace, and then heated and kept warm to obtain a precursor sheet, and then the precursor sheet is uniformly mixed with an alkaline solution, and then the dried mixture is placed in a tubular furnace, and then heated, roasted, and naturally cooled to obtain the conductive individual. The advantages of this design include: First point: The loose and porous tubular structure of lotus leaf stems is activated by alkalization to have strong water absorption and conduction capabilities, thus serving as the hub for controlling the moisture balance on the wound surface in this design, so as to achieve plant transpiration, thereby improving the wound liquid surface environment and enhancing wound healing efficiency; Second point: before heating and heat preservation to obtain the precursor sheet, the present design requires quick freezing, slicing, and freeze-drying to avoid the collapse of the internal three-dimensional pores caused by water loss during the subsequent heating and heat preservation process, thereby better preserving the three-dimensional pore structure, and then the precursor sheet can still maintain the three-dimensional pore structure after subsequent heating and roasting, so as to facilitate the subsequent plant transpiration; Third point: Compared with conventional negative pressure drainage, this conduction device has many advantages such as good portability, zero pressure on the wound, good wound drainage performance, and low cost; Fourth point: This conductive individual belongs to biomass activated carbon, which can absorb the odor of the wound and reduce the odor of the wound to avoid damaging the patient's treatment mentality, and has personality care effect for the patient; Therefore, the present invention not only ensures the three-dimensional hole structure inside the conduction individual to facilitate the moisture balance effect, but also has zero pressure on the wound, low cost, and can absorb odor.

[0019] 3. In the self-oxygenating dressing for oxygen therapy and healing of diabetic wounds of the present invention and the preparation method thereof, a flash-steamed nonwoven fabric is arranged between the all-cotton spunlace nonwoven fabric and the conductive layer. The advantages of this design include: First point: As an important wet environment control structure in this product, on the one hand, the flash nonwoven fabric can use the ultrafine fiber structure to control the water loss rate of the hydrogel. On the other hand, it also forms a one-way moisture-conducting structure with the outermost cotton spunlace nonwoven fabric (the raw material of the flash nonwoven fabric is high-density polyethylene, and the material has poor water absorption capacity, while the cotton fiber in the cotton spunlace nonwoven fabric has good water absorption performance and strong hydrophilicity. The two form a large moisture absorption capacity gradient difference, forming a one-way moisture-conducting structure). The transpiration of biomass carbon tubes will be used to quickly export the released water vapor molecules, maintain the wet environment balance of the wound, and improve the efficiency of tissue fluid control; Second point: The flash nonwoven fabric is made of 0.2-5 micron high-density polyethylene fibers arranged in a hybrid manner to form a uniform three-dimensional network structure. The fibers have an ultra-small diameter and excellent single-filament strength. After consolidation and molding, the nonwoven material has high strength and low hair loss rate. When used for wound dressings, no fibers will remain on the wound surface. Third point: In terms of antibacterial barrier properties, due to its three-dimensional network structure of ultrafine fibers, microorganisms must pass through the narrow and tortuous channels formed between the multi-layer stacked ultrafine fibers to penetrate this structure of materials. Therefore, flash-steamed nonwovens have a natural high microbial barrier, and it is difficult for external liquid media with bacteria to enter the wound; Therefore, the present invention not only has a unidirectional moisture conduction function, which is beneficial to achieving moisture balance of the wound, but also has a good antibacterial effect, is not prone to residual fibers, and can ensure gas exchange between the wound and the outside world.

[0020] 4. In the self-oxygenating dressing for oxygen therapy and healing of diabetic wounds of the present invention and the preparation method thereof, the self-oxygenating hydrogel is a three-dimensional network structure, and preferably the self-oxygenating hydrogel is formed by the three-dimensional network structure generated by PVA and the three-dimensional network structure generated by CMCS interlaced with each other. The advantages of this design include: First point: The double network hydrogel structure allows the network structures generated by PVA and CMCS to interpenetrate with each other. Compared with a single network, the double network hydrogel is not only more stable in structure and can improve the overall mechanical properties, but also because the two molecules are interpenetrated, the distance between the same molecules can be expanded, the gaps inside the hydrogel are increased, the space for water molecules to move is larger, and the overall water content of the hydrogel is improved. At the same time, in the subsequent repeated freezing and thawing process, the two molecules will produce different scaling rates, further generating more pores. In addition, the two have different attractions for water, which makes the cavities between different molecules more, thereby improving the water content as a whole and being more conducive to the efficient generation of dissolved oxygen. Second point: CMCS is an important water-soluble chitosan derivative. It not only has the functions of promoting wound healing, hemostasis, scar inhibition, analgesia, and antibacterial, but more importantly, it has good biocompatibility and biodegradability, and will not cause wound infection, discomfort, or adhesion, thereby improving the biocompatibility and antibacterial properties of the entire product; Third point: PVA is mainly responsible for constructing the polyvinyl alcohol network. The internal functional groups are more hydrophilic, which can significantly increase the overall water content of the entire hydrogel. At the same time, the molecular weight of PVA is relatively large compared to CMCS, so the overall mechanical properties will also be improved. In addition, PVA is an extremely safe macromolecular organic substance, non-toxic to the human body, has no side effects, and has good biocompatibility; Therefore, the present invention can not only construct a double-network hydrogel structure and improve the overall water content, but also has good biocompatibility and strong antibacterial performance.

[0021] 5. In the self-oxygenating dressing for oxygen therapy and healing of diabetic wounds of the present invention and the preparation method thereof, the flash nonwoven fabric, the conductive body, the secondary mixed liquid and the mold need to be frozen first and then thawed, and the operation is repeated 6-8 times. The design can promote the formation of a gel with a network structure. The reason is (taking PVA as an example, CMCS is similar to it): In a homogeneous PVA aqueous solution, PVA molecular chains are randomly distributed in the aqueous phase, the relative fluidity between the molecular chains is large, the contact time between each other is short, and it is difficult to achieve tight bonding. At this time, the freezing process can "freeze" the molecular motion state of the PVA aqueous solution at a certain moment, so that the molecular chains in contact with each other can interact with each other and are tightly bound by van der Waals forces and hydrogen bonds. Even some molecular chain segments in a certain micro-region can form an ordered structure, making the bonding stronger, so that after thawing at room temperature, these tightly bound ordered micro-regions no longer separate and become entanglement points. Subsequently, when refrozen, some new tightly bound ordered micro-regions are formed, new entanglement points are obtained, and even the entanglement points can be connected to form physical cross-linking points. The physical cross-linking points formed under freezing conditions are relatively stable, and their disintegration requires the absorption of a large amount of energy, so that the structure can still be maintained during subsequent thawing, and so on, repeatedly, thereby obtaining more physical cross-linking points, and then obtaining a more stable three-dimensional network structure. Therefore, the present invention can not only generate hydrogels through repeated freezing and thawing, but also improve the stability of the three-dimensional network structure of the hydrogel and enhance the mechanical strength of the double-network hydrogel structure.

[0022] 6. In the self-oxygenating dressing for oxygen therapy and healing of diabetic wounds of the present invention and the preparation method thereof, the all-cotton spunlace nonwoven fabric is preferably a grafted all-cotton spunlace nonwoven fabric. After grafting, the all-spunlace nonwoven fabric will have stronger hydrophilicity and further improve its hygroscopic capacity. It can form a larger hygroscopic capacity gradient with the flash nonwoven fabric, which is beneficial to improve the tissue fluid balance ability of the product. In addition, it can be more skin-friendly and hygienic. Therefore, the present invention not only has a better one-way moisture-conducting structure, has a strong moisture balance ability for the wound, but also is skin-friendly and hygienic.

[0023] 7. In the self-oxygenating dressing for oxygen therapy and healing of diabetic wounds of the present invention and the preparation method thereof, the Fe3O4-CaO2 nanoparticles preferably refer to composite particles obtained by physically binding Fe3O4 and CaO2 by HA, wherein the connection between the two nanoparticles of Fe3O4 and CaO2 by hyaluronic acid is a physical connection, which sticks the two substances together through its own viscosity so as to stably exist in the subsequent hydrogel. At the same time, the hyaluronic acid molecule HA is a polymer material containing a large number of carboxyl groups and hydroxyl groups, which can form intramolecular and molecular bonds in aqueous solution. The hydrogen bonds between the nanoparticles of Fe3O4 and CaO2 make it have a strong water-retaining effect, and it can combine at least 400 times more water than itself. It can not only combine strongly with the water contained in the hydrogel to fix the two nanoparticles of Fe3O4 and CaO2 more stably, but also absorb additional water in addition to the effect of the hydrogel containing water, so as to facilitate the generation of dissolved oxygen. In addition, the generation of dissolved oxygen depends on the two nanoparticles of Fe3O4 and CaO2, and these two nanoparticles are bound by hyaluronic acid that can combine more water, so that water can be provided in time at the beginning of the generation of dissolved oxygen, ensuring the efficient generation of dissolved oxygen. Therefore, the present invention can not only improve the firmness of the fixation of nanoparticles in the hydrogel, but also generate dissolved oxygen in time, and the generation efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the application of the present invention.

[0025] Figure 2 It is a preparation flow chart of the present invention.

[0026] Figure 3 This is a SEM image of the surface of the self-oxygenating hydrogel in the present invention at a resolution of 150 um. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0028] See also Figure 1 — Figure 3, a self-oxygenating dressing for oxygen therapy healing of diabetic wounds, the self-oxygenating dressing comprising, from top to bottom, a cotton spunlace nonwoven fabric, a flash-steamed nonwoven fabric, a conductive layer, and a self-oxygenating hydrogel, and the conductive layer comprises a plurality of conductive individuals arranged along the top surface of the self-oxygenating hydrogel, and the conductive individuals are hollow honeycomb structures; The top surface of the flash-steamed nonwoven fabric is connected to the bottom surface of the all-cotton spunlace nonwoven fabric, and the bottom surface of the flash-steamed nonwoven fabric is connected to the top surface of the self-oxygenating hydrogel, and all the conductive entities are sandwiched between the flash-steamed nonwoven fabric and the self-oxygenating hydrogel; The self-oxygenating hydrogel is a three-dimensional network structure, which contains water and Fe3O4-CaO2 nanoparticles; The moisture absorption capacity of the all-cotton spunlace nonwoven fabric is greater than that of the flash-steamed nonwoven fabric, and the conductive individual absorbs the water seeping from the top surface of the self-oxygenating hydrogel through capillary action.

[0029] The top surface of the flash-steamed nonwoven fabric is connected to the bottom surface of the all-cotton spunlace nonwoven fabric, which means that the periphery of the flash-steamed nonwoven fabric is connected to the periphery of the all-cotton spunlace nonwoven fabric through a waterproof adhesive tape, and at the same time, the middle part of the top surface of the flash-steamed nonwoven fabric is connected to the middle part of the bottom surface of the all-cotton spunlace nonwoven fabric through multiple bonding points.

[0030] The self-oxygenating hydrogel is a three-dimensional network structure, which means that the self-oxygenating hydrogel is formed by the three-dimensional network structure generated by PVA and the three-dimensional network structure generated by CMCS interlaced with each other.

[0031] The Fe3O4-CaO2 nanoparticles refer to composite particles formed by physically binding Fe3O4 and CaO2 by HA.

[0032] A method for preparing the above-mentioned self-oxygenating dressing for oxygen therapy healing of diabetic wounds, the preparation method comprising the following steps: The first step: firstly, PVA and water are used to prepare a paste-like PVA solution, in which the mass percentage concentration of PVA is 8%-10%, and then CMCS and water are used to prepare a CMCS solution, in which the mass percentage concentration of CMCS is 5%-8%, and then the PVA solution and the CMCS solution are mixed to obtain a primary mixed solution, in which the mass proportion of the PVA solution in the primary mixed solution is 30%-50%, and then Fe3O4-CaO2 nanoparticles are added to the primary mixed solution and uniformly dispersed to obtain a secondary mixed solution, in which the mass of the Fe3O4-CaO2 nanoparticles is 1%-5% of the primary mixed solution; Step 2: first turn over the flash nonwoven fabric, then place an annular mold on the top surface of the flash nonwoven fabric, then place a plurality of conductive individuals on the flash nonwoven fabric in the area within the mold, then inject the secondary mixed liquid into the mold, then seal the mold after the injection, and then freeze and thaw the flash nonwoven fabric, the conductive individuals, the secondary mixed liquid, and the mold together, repeat this operation 6-8 times, then release the mold seal, and remove the mold, at this time, the secondary mixed liquid has become a self-oxygenating hydrogel, and the self-oxygenating hydrogel, the flash nonwoven fabric, and all the conductive individuals are connected into an integrated structure; Step 3: First, flip the flash-steamed nonwoven fabric together with the conductive individual and self-oxygenating hydrogel back to their original position, and then connect the top surface of the flash-steamed nonwoven fabric to the bottom surface of the all-cotton spunlace nonwoven fabric to obtain the above-mentioned self-oxygenating dressing for oxygen therapy healing of diabetic wounds.

[0033] In the second step, the conductive individual is prepared according to the following steps: first, fresh lotus leaf stems are picked, then purified, and then quickly frozen with liquid nitrogen, and then the lotus leaf stems after quick freezing are sliced, and then the slices are placed in a vacuum freeze dryer for freeze drying, and then the freeze-dried slices are placed in a tubular furnace, and in a nitrogen atmosphere, the temperature is raised from room temperature to 180°C-220°C, and kept warm for 0.8-1.2h to obtain a precursor sheet, and then the precursor sheet is evenly mixed with an alkaline solution, and then the mixture is dried, and then the residue after drying is placed in a tubular furnace, heated to 380°C-420°C, and roasted for 0.8-1.2h, and then naturally cooled to ambient temperature to obtain a conductive individual.

[0034] After naturally cooling to ambient temperature, the substrate is first immersed in HCl solution, then rinsed with deionized water, and then the pH value is tested, and the cycle is repeated until the measured pH value is 7-7.3, and then dried to obtain a conductive individual.

[0035] In the second step, the freezing temperature is -20°C to -30°C, and the thawing is performed at room temperature.

[0036] In the first step, the preparation steps of the PVA solution are: first add PVA to a beaker, then add water, then seal the beaker, and then heat them in a water bath until they are at 60°C, then keep them warm until the PVA is obviously swollen, then heat them to 90°C, and then magnetically stir the beaker at the temperature until the PVA is fully dissolved to obtain a paste-like PVA solution; In the first step, the CMCS solution is prepared by first adding powdered CMCS into a beaker, then adding water, then sealing the beaker, and then magnetically stirring the beaker until the CMCS is fully dissolved to obtain a CMCS solution.

[0037] In the third step, the all-cotton spunlace nonwoven fabric is a grafted all-cotton spunlace nonwoven fabric, and its preparation steps are: first immerse the all-cotton spunlace nonwoven fabric in an isopropanol solution, then seal it and place it in a magnetic stirrer, set the temperature to 35-45°C, keep it at a constant temperature for 30-50 minutes, then open the seal, add sodium hydroxide solution, then seal it, heat it to 40-50°C, keep it warm and stir it for 40-60 minutes, and then let it stand for 0.8-1.2 hours to allow the cotton fiber to react with the sodium hydroxide. The sodium cellulose is obtained by fully reacting, and the temperature remains unchanged during the reaction. The seal is then opened, and a mixture of chloroacetic acid and isopropanol is added, and the seal is then re-adjusted to 20-25°C and reacted for 7-9 hours to obtain modified cotton fibers. The modified cotton fibers are then taken out and the pH value is adjusted to 7-7.3 with glacial acetic acid, and then washed three times with 80% ethanol and anhydrous ethanol, and then dried to obtain a grafted all-cotton spunlace nonwoven fabric. The grafted all-cotton spunlace nonwoven fabric has a moisture absorption capacity greater than that of the above-mentioned all-cotton spunlace nonwoven fabric.

[0038] The supplementary technical features of the present invention are as follows: The basic purpose of the present invention is to provide dissolved oxygen to the wound to promote angiogenesis at the wound and improve the wound healing effect. The main functions of oxygen in the wound recovery process include: Regulating oxygen receptors: The involvement of oxygen receptors in the transduction of hypoxic cells is a complex and diverse process. Once cells are hypoxic, wound healing is delayed. Although hyperbaric oxygen therapy can increase the oxygen partial pressure of tissue cells throughout the body, excessive oxygen partial pressure will produce too much ROS, causing the body to produce lipid peroxidation reactions, causing damage to tissues and organs, and bringing many adverse reactions to patients. Local oxygen therapy can provide appropriate oxygen partial pressure for the wound, promote wound healing by regulating oxygen receptors, and avoid the occurrence of systemic complications; Anti-infection effect: The bactericidal effect of oxygen is mainly to increase the activity of white blood cells, kill cells and necrotic tissues, thereby inhibiting bacterial growth and accelerating wound healing; Promote cell growth: Wound healing mainly relies on the generation of fibroblasts, synthesis of collagen cells and filling of granulation tissue. When the wound is severely hypoxic, the proliferation of fibroblasts will slow down or stop, and the quality and quantity of collagen will decrease, affecting wound healing. Oxygen can promote the synthesis of wound collagen and angiogenesis, and promote energy metabolism and the expression of various growth factors. The role of promoting microcirculation: Tissue edema and blood stasis can lead to microcirculation disorders, which prevent local tissues from obtaining the nutrients they need. This is an important reason for non-healing wounds. Local oxygen therapy can effectively reduce tissue edema and is beneficial to the normal growth of endothelial cells and capillaries.

[0039] In the present invention, PVA refers to polyvinyl alcohol, CMCS refers to carboxymethyl chitosan, and HA refers to hyaluronic acid.

[0040] When the middle part of the flash-steamed nonwoven fabric in the present invention is connected to the middle part of the all-cotton spunlace nonwoven fabric through a plurality of bonding points, resin glue is preferably used at the bonding points.

[0041] The purification treatment of the fresh lotus leaf stem in the present invention refers to first removing the surface burrs with sandpaper and then washing.

[0042] When the sheet is placed in a vacuum freeze dryer for freeze drying in the present invention, the freeze drying time is preferably 48 hours to maintain its original biomass structure.

[0043] In the present invention, the freeze-dried sheet is placed in a tubular furnace and heated to 180°C-220°C, and then placed in a tubular furnace and heated to 380°C-420°C. The heating rate is preferably 5°C•min-1.

[0044] The HCl solution in the HCl solution impregnation in the present invention means that there is 1 mol of HCl molecules per liter of solution.

[0045] The reason for adjusting the temperature to 20-25° C. in the present invention is that if the temperature is lower than this, the reaction rate is slow, while if the temperature is higher than this, the solvent evaporates too quickly, and since the cellulose in the cotton fiber is a macromolecular chain, the reaction rate will be too high, causing the cotton spunlace nonwoven fabric to fall apart.

[0046] Embodiment 1: See also Figure 1 — Figure 2 A self-oxygenating dressing for oxygen therapy healing of diabetic wounds, the self-oxygenating dressing comprising a pure cotton spunlace nonwoven fabric, a flash-steamed nonwoven fabric, a conductive layer, and a self-oxygenating hydrogel arranged in sequence from top to bottom, and the conductive layer comprises a plurality of conductive individuals arranged along the top surface of the self-oxygenating hydrogel, the conductive individuals being a hollow honeycomb structure; the top surface of the flash-steamed nonwoven fabric is connected to the bottom surface of the pure cotton spunlace nonwoven fabric, the bottom surface of the flash-steamed nonwoven fabric is connected to the top surface of the self-oxygenating hydrogel, and all the conductive individuals are sandwiched between the flash-steamed nonwoven fabric and the self-oxygenating hydrogel; the self-oxygenating hydrogel is a three-dimensional network structure, containing water and Fe3O4-CaO2 nanoparticles; the moisture absorption capacity of the pure cotton spunlace nonwoven fabric is greater than that of the flash-steamed nonwoven fabric, and the conductive individuals absorb water seeping from the top surface of the self-oxygenating hydrogel through capillary action.

[0047] A method for preparing the above-mentioned self-oxygenating dressing for oxygen therapy healing of diabetic wounds, the preparation method comprising the following steps: The first step: firstly, PVA and water are used to prepare a paste-like PVA solution, in which the mass percentage concentration of PVA is 8%-10%, and then CMCS and water are used to prepare a CMCS solution, in which the mass percentage concentration of CMCS is 5%-8%, and then the PVA solution and the CMCS solution are mixed to obtain a primary mixed solution, in which the mass proportion of the PVA solution in the primary mixed solution is 30%-50%, and then Fe3O4-CaO2 nanoparticles are added to the primary mixed solution and uniformly dispersed to obtain a secondary mixed solution, in which the mass of the Fe3O4-CaO2 nanoparticles is 1%-5% of the primary mixed solution; Step 2: first turn over the flash nonwoven fabric, then place an annular mold on the top surface of the flash nonwoven fabric, then place a plurality of conductive individuals on the flash nonwoven fabric in the area within the mold, then inject the secondary mixed liquid into the mold, then seal the mold after the injection, and then freeze and then thaw the flash nonwoven fabric, the conductive individuals, the secondary mixed liquid, and the mold together (preferably the freezing temperature is -20°C to -30°C, and the thawing is performed at room temperature), the operation is repeated 6-8 times, then the mold is unsealed and removed, at which point the secondary mixed liquid has become a self-oxygenating hydrogel, and the self-oxygenating hydrogel, the flash nonwoven fabric, and all the conductive individuals are connected into an integrated structure; Step 3: First, flip the flash-steamed nonwoven fabric together with the conductive individual and self-oxygenating hydrogel back to their original position, and then connect the top surface of the flash-steamed nonwoven fabric to the bottom surface of the all-cotton spunlace nonwoven fabric to obtain the above-mentioned self-oxygenating dressing for oxygen therapy healing of diabetic wounds.

[0048] Embodiment 2: The basic content is the same as that of Example 1, except that: The self-oxygenating hydrogel is a three-dimensional network structure, which means that the self-oxygenating hydrogel is formed by the interlacing of the three-dimensional network structure generated by PVA and the three-dimensional network structure generated by CMCS. The Fe3O4-CaO2 nanoparticles are composite particles formed by physically binding Fe3O4 and CaO2 by HA.

[0049] like Figure 3 As shown, this figure is a SEM image of the surface of the self-oxygenating hydrogel of the present invention at a resolution of 150 um. The figure shows an obvious network structure, showing a multiple honeycomb structure that is intertwined inside and outside.

[0050] Embodiment 3: The basic content is the same as that of Example 1, except that: In the second step, the conductive individual is prepared according to the following steps: first, fresh lotus leaf stems are picked, then purified, and then quickly frozen with liquid nitrogen, and then the lotus leaf stems after quick freezing are sliced, and then the slices are placed in a vacuum freeze dryer for freeze drying, and then the freeze-dried slices are placed in a tube furnace, and in a nitrogen atmosphere, the temperature is raised from room temperature to 180°C-220°C (preferably 200°C), and kept warm for 0.8-1.2h (preferably 1h) to obtain a precursor sheet, and then the precursor sheet is uniformly mixed with an alkaline solution, and then the mixture is dried, and then the residue after drying is placed in a tube furnace, heated to 380°C-420°C (preferably 400°C), and roasted for 0.8-1.2h (preferably 1h), and then naturally cooled to ambient temperature, and then immersed in HCl solution, and then rinsed with deionized water, and then the pH value is tested, and the cycle is repeated in sequence until the measured pH value is 7-7.3 (preferably 7), and then dried to obtain a conductive individual.

[0051] Embodiment 4: The basic content is the same as that of Example 1, except that: In the first step, the preparation steps of the PVA solution are: first add PVA to a beaker, then add water, then seal the beaker, and then heat them in a water bath until they are at 60°C, then keep them warm until the PVA is obviously swollen, then heat them to 90°C, and then magnetically stir the beaker at the temperature until the PVA is fully dissolved to obtain a paste-like PVA solution; In the first step, the CMCS solution is prepared by first adding powdered CMCS into a beaker, then adding water, then sealing the beaker, and then magnetically stirring the beaker until the CMCS is fully dissolved to obtain a CMCS solution.

[0052] Embodiment 5: The basic contents are the same as those of Example 4, except that: In the first step, 5 g of polyvinyl alcohol (PVA) was weighed, 45 ml of sterile ultrapure water was added to a clean beaker, and the mixture was heated to 60° C. in a constant temperature water bath without stirring. After 1 hour, the PVA was obviously swollen. Then, the constant temperature water bath was heated to 90°C, the beaker was sealed, and the mixture was stirred repeatedly for about 3 hours to fully dissolve the PVA. It was observed that the PVA was completely dissolved into a paste, and no particles were found in the solution, so as to obtain a PVA aqueous solution with a mass percentage concentration of 10%. At the same time, 20 g of carboxymethyl chitosan (CMCS) powder was weighed into a clean beaker, and then a carboxymethyl chitosan solution with a mass fraction of 5% was prepared, and the solution was stirred on a magnetic stirrer for 1 hour to fully dissolve the carboxymethyl chitosan powder, so as to obtain a CMCS solution. Subsequently, the PVA aqueous solution and the CMCS solution were mixed in a mass ratio of 5:5, and then allowed to stand for defoaming to obtain a primary mixed solution, and then 0.5 g of Fe3O4-CaO2 nanoparticles were added to 50 ml of the primary mixed solution, and then ultrasonically treated for 30 minutes, and then allowed to stand for defoaming to obtain a secondary mixed solution.

[0053] The static defoaming means that since the solution is a relatively thick colloid, air will enter the liquid during stirring and produce bubbles. Therefore, this design will let the stirred liquid stand for a period of time. The bubbles in the liquid will float to the surface of the solution due to their own buoyancy, leaving no bubbles in the lower layer of colloid.

[0054] Embodiment 6: The basic content is the same as that of Example 1, except that: In the first step, the Fe3O4-CaO2 nanoparticles are prepared according to the following steps: first, 0.4g of anhydrous calcium chloride and 150mg of hyaluronic acid (HA) are added to 20ml of anhydrous ethanol, and then ultrasonically dissolved for 10 minutes, and then placed in a magnetic stirrer for magnetic stirring. During the stirring process, 2ml of ammonia solution and 3ml of hydrogen peroxide solution (mass percentage concentration is 30%) are added dropwise in sequence. When the solution is observed to gradually turn milky white, the stirring is stopped, and then centrifuged at 10000rpm for 10min using a centrifuge, and then the solid product is collected, and then the solid product is dissolved in 20ml of anhydrous ethanol, stirred for 24h, and finally centrifuged at 12000rpm for 10min to obtain Fe3O4-CaO2 nanoparticles.

[0055] The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. Any equivalent modifications or changes made by ordinary technicians in this field based on the contents disclosed by the present invention should be included in the protection scope recorded in the claims.

Claims

1. A self-oxygenating dressing for oxygen therapy healing of diabetic wounds, Features: The self-oxygenating dressing comprises a cotton spunlace nonwoven fabric, a flash-steamed nonwoven fabric, a conductive layer, and a self-oxygenating hydrogel arranged in sequence from top to bottom, and the conductive layer comprises a plurality of conductive entities arranged along the top surface of the self-oxygenating hydrogel, and the conductive entities are hollow honeycomb structures; The top surface of the flash-steamed nonwoven fabric is connected to the bottom surface of the all-cotton spunlace nonwoven fabric, and the bottom surface of the flash-steamed nonwoven fabric is connected to the top surface of the self-oxygenating hydrogel, and all the conductive entities are sandwiched between the flash-steamed nonwoven fabric and the self-oxygenating hydrogel; The self-oxygenating hydrogel is a three-dimensional network structure, which contains water and Fe3O4-CaO2 nanoparticles; The moisture absorption capacity of the all-cotton spunlace nonwoven fabric is greater than that of the flash-steamed nonwoven fabric, and the conductive individual absorbs the water seeping from the top surface of the self-oxygenating hydrogel through capillary action.

2. A self-oxygenating dressing for oxygen therapy healing of diabetic wounds according to claim 1, Features: The top surface of the flash-steamed nonwoven fabric is connected to the bottom surface of the all-cotton spunlace nonwoven fabric, which means that the periphery of the flash-steamed nonwoven fabric is connected to the periphery of the all-cotton spunlace nonwoven fabric through a waterproof adhesive tape, and at the same time, the middle part of the top surface of the flash-steamed nonwoven fabric is connected to the middle part of the bottom surface of the all-cotton spunlace nonwoven fabric through multiple bonding points.

3. A self-oxygenating dressing for oxygen therapy healing of diabetic wounds according to claim 1 or 2, Features: The self-oxygenating hydrogel is a three-dimensional network structure, which means that the self-oxygenating hydrogel is formed by the three-dimensional network structure generated by PVA and the three-dimensional network structure generated by CMCS interlaced with each other.

4. A self-oxygenating dressing for oxygen therapy healing of diabetic wounds according to claim 1 or 2, Features: The Fe3O4-CaO2 nanoparticles refer to composite particles formed by physically binding Fe3O4 and CaO2 by HA.

5. A method for preparing the self-oxygenating dressing for oxygen therapy healing of diabetic wounds according to claim 1 or 2, Features: The preparation method comprises the following steps: The first step: firstly, PVA and water are used to prepare a paste-like PVA solution, in which the mass percentage concentration of PVA is 8%-10%, and then CMCS and water are used to prepare a CMCS solution, in which the mass percentage concentration of CMCS is 5%-8%, and then the PVA solution and the CMCS solution are mixed to obtain a primary mixed solution, in which the mass proportion of the PVA solution in the primary mixed solution is 30%-50%, and then Fe3O4-CaO2 nanoparticles are added to the primary mixed solution and uniformly dispersed to obtain a secondary mixed solution, in which the mass of the Fe3O4-CaO2 nanoparticles is 1%-5% of the primary mixed solution; Step 2: first turn over the flash nonwoven fabric, then place an annular mold on the top surface of the flash nonwoven fabric, then place a plurality of conductive individuals on the flash nonwoven fabric in the area within the mold, then inject the secondary mixed liquid into the mold, then seal the mold after the injection, and then freeze and thaw the flash nonwoven fabric, the conductive individuals, the secondary mixed liquid, and the mold together, repeat this operation 6-8 times, then release the mold seal, and remove the mold, at this time, the secondary mixed liquid has become a self-oxygenating hydrogel, and the self-oxygenating hydrogel, the flash nonwoven fabric, and all the conductive individuals are connected into an integrated structure; Step 3: First, flip the flash-steamed nonwoven fabric together with the conductive individual and self-oxygenating hydrogel back to their original position, and then connect the top surface of the flash-steamed nonwoven fabric to the bottom surface of the all-cotton spunlace nonwoven fabric to obtain the above-mentioned self-oxygenating dressing for oxygen therapy healing of diabetic wounds.

6. A method for preparing a self-oxygenating dressing for oxygen therapy healing of diabetic wounds according to claim 5, Features: In the second step, the conductive entity is prepared according to the following steps: First, fresh lotus leaf stems are picked, purified, and then quickly frozen with liquid nitrogen. The quick-frozen lotus leaf stems are sliced, and then the slices are placed in a vacuum freeze dryer for freeze-drying. The freeze-dried slices are placed in a tubular furnace, and in a nitrogen atmosphere, the temperature is raised from room temperature to 180°C-220°C, and kept warm for 0.8-1.2 hours to obtain a precursor sheet, and then the precursor sheet is evenly mixed with an alkaline solution, and the mixture is dried. The residue after drying is then placed in a tubular furnace, heated to 380°C-420°C, and roasted for 0.8-1.2 hours, and then naturally cooled to ambient temperature to obtain a conductive individual.

7. A method for preparing a self-oxygenating dressing for oxygen therapy healing of diabetic wounds according to claim 6, Features: After naturally cooling to ambient temperature, the substrate is first immersed in HCl solution, then rinsed with deionized water, and then the pH value is tested, and the cycle is repeated until the measured pH value is 7-7.3, and then dried to obtain a conductive individual.

8. A method for preparing a self-oxygenating dressing for oxygen therapy healing of diabetic wounds according to claim 5, Features: In the second step, the freezing temperature is -20°C to -30°C, and the thawing is performed at room temperature.

9. A method for preparing a self-oxygenating dressing for oxygen therapy healing of diabetic wounds according to claim 5, Features: In the first step, the preparation steps of the PVA solution are: first add PVA to a beaker, then add water, then seal the beaker, and then heat them in a water bath until they are at 60°C, then keep them warm until the PVA is obviously swollen, then heat them to 90°C, and then magnetically stir the beaker at the temperature until the PVA is fully dissolved to obtain a paste-like PVA solution; In the first step, the CMCS solution is prepared by first adding powdered CMCS into a beaker, then adding water, then sealing the beaker, and then magnetically stirring the beaker until the CMCS is fully dissolved to obtain a CMCS solution.

10. A method for preparing a self-oxygenating dressing for oxygen therapy healing of diabetic wounds according to claim 5, Features: In the third step, the all-cotton spunlace nonwoven fabric is a grafted all-cotton spunlace nonwoven fabric, and the preparation steps are as follows: First, 100% cotton spunlace nonwoven fabric is immersed in an isopropanol solution, and then sealed and placed in a magnetic stirrer, the temperature is set to 35-45°C, and the fabric is placed at a constant temperature for 30-50 minutes. Then, the seal is opened, and a sodium hydroxide solution is added, and then the seal is opened. After the temperature is raised to 40-50°C, the fabric is stirred for 40-60 minutes and then allowed to stand for 0.8-1.2 hours, so that the cotton fiber and the sodium hydroxide fully react to obtain sodium cellulose. During the reaction, the temperature remains unchanged, and then the seal is opened, and then a mixture of chloroacetic acid and isopropanol is added, and then the temperature is adjusted to 20-25°C and reacted for 7-9 hours to obtain modified cotton fiber. The modified cotton fiber is taken out, the pH value is adjusted to 7-7.3 with glacial acetic acid, and then it is washed three times with 80% ethanol and anhydrous ethanol, and then dried to obtain a grafted 100% cotton spunlace nonwoven fabric. The grafted 100% cotton spunlace nonwoven fabric has a moisture absorption capacity greater than that of the above-mentioned 100% cotton spunlace nonwoven fabric.

Images