Preparation method of magnetic self-oxygen-supplying hydrogel dressing and dressing

Abstract

The application discloses a preparation method of a magnetic self-oxygen-supplying hydrogel dressing. PVA and water are mixed, and then two-stage temperature-rising water bath heating is carried out in a sealed manner, and then magnetic stirring is carried out at the highest temperature to obtain a paste-shaped PVA solution; meanwhile, CMCS and water are mixed, and then magnetic stirring is carried out in a sealed manner to obtain a CMCS solution; subsequently, the PVA solution and the CMCS solution are mixed to obtain a first mixed solution, Fe3O4-CaO2 nanoparticles are added into the first mixed solution to obtain a second mixed solution, the second mixed solution is introduced into a mold, the mold is sealed, and then repeated freezing and thawing are carried out to obtain the magnetic self-oxygen-supplying hydrogel dressing. The design can not only autonomously generate dissolved oxygen and directly provide oxygen therapy to facilitate angiogenesis, but also balance the humidity of a wound and provide magnetic therapy, and the wound healing effect is better.

Description

Technical Field

[0001] The invention relates to a medical dressing, belonging to the technical field of diabetic wound healing, and in particular to a preparation method of a magnetic self-oxygenating hydrogel dressing and the dressing. Background Art

[0002] Diabetes can cause many complications, and diabetic foot ulcers are currently the most common diabetic complication that requires hospitalization. Among them, 20% of diabetic foot patients require amputation, and the overall mortality rate of diabetic foot ulcers within 5 years of onset is as high as 50%.

[0003] The fundamental reason why diabetic foot ulcers have such high rates of disability and mortality is that ischemia in the wound surface delays healing. Addressing ischemia requires addressing angiogenesis, and the key to addressing angiogenesis is addressing wound hypoxia. Therefore, to shorten the healing time of diabetic foot ulcers and reduce mortality and amputation rates, many new auxiliary technologies have emerged in clinical practice, including oxygen therapy.

[0004] Existing oxygen therapy technologies include hyperbaric oxygen therapy and topical oxygen therapy (TOT). Hyperbaric oxygen therapy requires a hyperbaric oxygen chamber and has high environmental requirements. Patients can only go to the hospital for treatment, which is not only very inconvenient but also very expensive. Topical oxygen therapy, on the other hand, is to pressurize humidified pure oxygen to 10-50MB in a cycle of 20 seconds and deliver it to oxygen bags around the affected limb to provide oxygen to the wound. The treatment lasts for 90 minutes a day and 4-5 times a week. A lot of financial and energy resources are consumed during the treatment. At the same time, because TOT acts on the wound through gaseous oxygen, not only is the oxygen utilization rate low, but it can also cause the wound to dry and shrink, deepen the ulcer wound, and is not conducive to wound healing.

[0005] The invention patent application with application number 202110811536.1 and application date July 19, 2021 discloses an antibacterial hydrogel dressing for diabetic wound repair and its preparation method. The method first prepares a TiO2 / Ag3PO4 phosphate suspension, then prepares a polyacrylic acid aqueous solution, a calcium chloride aqueous solution, and a glucose oxidase aqueous solution, and then mixes the polyacrylic acid aqueous solution, the calcium chloride aqueous solution, and the glucose oxidase aqueous solution, and adds the TiO2 / Ag3PO4 phosphate suspension under vigorous stirring to obtain an antibacterial hydrogel dressing. Although this design can respond to phosphate in a physiological environment, causing Ca2+ to escape, inducing gel degradation, and releasing TiO2 / Ag3PO4 and GOx, among which Gox can decompose glucose in the wound and reduce local blood glucose concentration, while TiO2 catalyzes H2O2 to generate reactive oxygen species (ROS) under light, synergistically killing Ag+ to reduce blood glucose concentration in the wound to promote diabetic wound healing, the design still has the following defects:

[0006] The design focuses primarily on lowering local blood sugar concentration, and secondarily on sterilization. It does not consider the relationship between oxygen therapy and angiogenesis. It cannot directly solve the problem of wound healing, but can only affect wound healing from the perspective of lowering blood sugar, resulting in poor healing effect.

[0007] The information disclosed in this background technology section is only intended to increase understanding of the overall background of the application and should not be considered as an admission or any form of suggestion that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the Invention

[0008] The purpose of the present invention is to overcome the defects and problems of the prior art that it cannot directly provide oxygen therapy to facilitate angiogenesis and has poor wound healing effect, and to provide a preparation method and dressing of a magnetic self-oxygenating hydrogel dressing that can directly provide oxygen therapy to facilitate angiogenesis and has better wound healing effect.

[0009] To achieve the above objectives, the technical solution of the present invention is: a method for preparing a magnetic self-oxygenating hydrogel dressing, the preparation method comprising the following steps:

[0010] Step 1: First add PVA into a beaker, then add water, then seal the beaker, and heat them together in a water bath until they reach Temperature A, then keep them warm until the PVA swells significantly, then heat them to Temperature B, and then magnetically stir the beaker at Temperature B until the PVA is fully dissolved to obtain a paste-like PVA solution with a mass percentage concentration of 8%-10% in the solution.

[0011] Step 2: First, add powdered CMCS into a beaker, then add water, seal the beaker, and then stir the beaker magnetically until the CMCS is fully dissolved to obtain a CMCS solution with a mass percentage concentration of CMCS in the solution of 5% to 8%;

[0012] Step 3: First, the PVA solution and 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 to obtain a secondary mixed solution, in which the mass of the Fe3O4-CaO2 nanoparticles is 1%-5% of the primary mixed solution. Then, the evenly dispersed secondary mixed solution is introduced into a mold, and the mold is sealed, then frozen, and then thawed. This freezing and thawing process is repeated 6-8 times, and then the seal of the mold is removed to obtain the magnetic self-oxygenating hydrogel dressing.

[0013] In the third step, the freezing temperature is -20°C to -30°C.

[0014] In the third step, the freezing time is 20 hours, and the thawing is carried out at room temperature.

[0015] In the third step, the uniform dispersion refers to ultrasonic dispersion of the secondary mixed liquid, and the dispersion time is 30 minutes.

[0016] In the third step, after obtaining the primary mixed solution, the mixture is allowed to stand for defoaming, and then the Fe3O4-CaO2 nanoparticles are added;

[0017] At the same time, before the secondary mixed liquid is introduced into the mold, the uniformly dispersed secondary mixed liquid is first allowed to stand and defoam.

[0018] In the first step, the temperature of step A is 60°C, and the temperature of step B is 90°C.

[0019] In the first step, the mass percentage concentration of PVA in the PVA solution is 10%;

[0020] In the second step, the mass percentage concentration of CMCS in the CMCS solution is 5%;

[0021] In the third step, the mass ratio of the PVA solution in the primary mixed solution is 50%.

[0022] In the first step, the beaker was not stirred during the entire process from the start of water bath heating to the obvious swelling of the PVA.

[0023] In the third step, the Fe3O4-CaO2 nanoparticles refer to composite particles formed by physically binding Fe3O4 and CaO2 by HA.

[0024] A magnetic self-oxygenating hydrogel dressing is a dressing prepared by the method for preparing the magnetic self-oxygenating hydrogel dressing.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. In a preparation method and dressing of a magnetic self-oxygenating hydrogel dressing of the present invention, a paste-like PVA solution and a CMCS solution are first prepared, and then the PVA solution and the CMCS solution are mixed to obtain a primary mixed solution, wherein the mass proportion of the PVA solution in the primary mixed solution is 30%-50%. Fe3O4-CaO2 nanoparticles are then added to the primary mixed solution to obtain a secondary mixed solution, wherein the mass of the Fe3O4-CaO2 nanoparticles is 1%-5% of the primary mixed solution. The uniformly dispersed secondary mixed solution is then introduced into a mold, and the mold is sealed. The freezing and thawing operations are repeated multiple times, and then the mold seal is removed and the final dressing is removed from the mold to obtain the magnetic self-oxygenating hydrogel dressing. The advantages of this design include:

[0027] First point: The Fe3O4-CaO2 nanoparticles introduced during the preparation process can provide Fe3O4 and CaO2 for the final product. At the same time, water is stored in the hydrogel, and calcium peroxide reacts with water to generate hydrogen peroxide and calcium hydroxide. Hydrogen peroxide decomposes to produce oxygen, and ferroferric oxide can catalyze the process of hydrogen peroxide producing oxygen, as shown below:

[0028] CaO2+2H2O → H2O2+Ca(OH)2;

[0029] H2O2+2Fe 3+ → 2Fe 2+ +O 2 +2H + ;

[0030] Fe 2+ + H2O2→ Fe 3+ +(OH) - +OH· ;

[0031] 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 deep into the wound of diabetic patients (dissolved oxygen can penetrate human skin thicker than 700μm, while local gaseous oxygen can only penetrate the dermis layer of 300μm), providing an oxygen-rich environment for wound recovery, directly promoting angiogenesis, and improving wound healing.

[0032] Second, the hydrogel's internal structure is a three-dimensional network with strong water retention. This not only supports the self-oxygenation reaction and ensures the smooth generation of dissolved oxygen, but also absorbs tissue fluid exuded from the wound, replenishing the raw materials for dissolved oxygen generation and improving oxygen supply efficiency. Furthermore, after saturation, the hydrogel releases water from the hydrogel in a free state, thereby balancing the moisture content of the wound. This ensures the moisture content of the wound is sufficient for healing, preventing dryness and adhesion of the wound surface (such as in topical oxygen therapy in the prior art), while also preventing excessive moisture from hindering wound healing.

[0033] Third point: The Fe3O4 in Fe3O4-CaO2 nanoparticles has its own magnetism, which can provide a magnetic field for chronic wounds, allowing magnetic lines of force to penetrate deep into human tissues, accelerating cell renewal, enhancing the vitality of blood cells, purifying the blood, improving microcirculation, and enhancing wound healing.

[0034] Therefore, the present invention can not only autonomously generate dissolved oxygen and directly provide oxygen therapy to facilitate angiogenesis, but also balance the moisture content of the wound and provide magnetic therapy, resulting in better wound healing effect.

[0035] 2. In the preparation method and dressing of a magnetic self-oxygenating hydrogel dressing of the present invention, PVA and CMCS together construct the framework structure of the hydrogel, realizing a three-dimensional double network structure. The advantages of this design include:

[0036] First point: The double-network hydrogel structure enables the network structures generated by PVA and CMCS to interpenetrate with each other as a whole. 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 becomes larger, and the overall water content of the hydrogel is improved. At the same time, during the subsequent repeated freezing and thawing process, the two molecules will produce different scaling rates, further generating more pores. In addition, the different attraction of the two to water will result in more cavities between different molecules, thereby increasing the water content as a whole and being more conducive to the efficient generation of dissolved oxygen.

[0037] Second, CMCS is an important water-soluble chitosan derivative that not only promotes wound healing, stops bleeding, inhibits scarring, relieves pain, and inhibits bacteria, but more importantly, it has excellent biocompatibility and biodegradability, preventing wound infection, discomfort, or adhesion, thereby enhancing the biocompatibility and antibacterial properties of the entire product.

[0038] Third point: PVA is mainly responsible for building the polyvinyl alcohol network. The internal functional groups are more hydrophilic, which can significantly increase the overall water content of the hydrogel. At the same time, the molecular weight of PVA is larger than that of CMCS, so the overall mechanical properties will also be improved. In addition, PVA is an extremely safe high-molecular organic substance, non-toxic to the human body, has no side effects, and has good biocompatibility.

[0039] 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.

[0040] 3. In the preparation method and dressing of a magnetic self-oxygenating hydrogel dressing of the present invention, after Fe3O4-CaO2 nanoparticles are added to a primary mixture to obtain a secondary mixture and uniformly dispersed, the secondary mixture is first introduced into a mold, the mold is then sealed, and then a "freezing and thawing" operation is repeated to produce the magnetic self-oxygenating hydrogel dressing. This design can promote the formation of a gel with a network structure. The reason for this is (taking PVA as an example, CMCS is similar to it):

[0041] In a homogeneous PVA aqueous solution, PVA molecular chains are randomly distributed in the aqueous phase. The relative mobility between the molecular chains is large, the contact time between them 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, allowing the molecular chains in contact with each other to interact with each other and tightly bond through van der Waals forces and hydrogen bonds. Even some molecular chain segments within a certain microregion can form an ordered structure, making the bonding stronger. After thawing at room temperature, these tightly bound ordered microregions no longer separate and become entanglement points. Subsequently, when refrozen, some new tightly bound ordered microregions are formed, obtaining new entanglement points, and even the entanglement points can be connected to form physical cross-linking points. The physical cross-linking points formed under freezing are relatively stable, and their disintegration requires the absorption of a large amount of energy. Therefore, the structure can still be maintained during subsequent thawing. Similarly, the process is repeated continuously, thereby obtaining more physical cross-linking points and 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.

[0042] 4. In the preparation method and dressing of a magnetic self-oxygenating hydrogel dressing of the present invention, the Fe3O4-CaO2 nanoparticles preferably refer to composite particles formed by physically binding Fe3O4 and CaO2 by HA, wherein the link between the Fe3O4 and CaO2 nanoparticles by hyaluronic acid is a physical link, which sticks the two substances together through their 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 and hydroxyl groups, which can form intramolecular and intermolecular hydrogen bonds in aqueous solution. The hyaluronic acid binds to the hydrogel, which gives it a strong water-retention effect and can bind at least 400 times more water than itself. Not only can it strongly bind to the water contained in the hydrogel to more stably fix the two nanoparticles of Fe3O4 and CaO2, but it can also absorb additional water in addition to the effect of the hydrogel containing water, thereby facilitating 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 the hyaluronic acid that can bind more water. Therefore, water can be provided in a timely manner 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 a timely manner with high generation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a SEM image of the surface of the hydrogel in the present invention at a resolution of 150 μm.

[0044] Figure 2 Schematic diagram of the double network structure of the hydrogel in the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] See also Figure 1 — Figure 2 A method for preparing a magnetic self-oxygenating hydrogel dressing, comprising the following steps:

[0047] Step 1: First add PVA into a beaker, then add water, then seal the beaker, and heat them together in a water bath until they reach Temperature A, then keep them warm until the PVA swells significantly, then heat them to Temperature B, and then magnetically stir the beaker at Temperature B until the PVA is fully dissolved to obtain a paste-like PVA solution with a mass percentage concentration of 8%-10% in the solution.

[0048] Step 2: First, add powdered CMCS into a beaker, then add water, seal the beaker, and then stir the beaker magnetically until the CMCS is fully dissolved to obtain a CMCS solution with a mass percentage concentration of CMCS in the solution of 5% to 8%;

[0049] Step 3: First, the PVA solution and 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 to obtain a secondary mixed solution, in which the mass of the Fe3O4-CaO2 nanoparticles is 1%-5% of the primary mixed solution. Then, the evenly dispersed secondary mixed solution is introduced into a mold, and the mold is sealed, then frozen, and then thawed. This freezing and thawing process is repeated 6-8 times, and then the seal of the mold is removed to obtain the magnetic self-oxygenating hydrogel dressing.

[0050] In the third step, the freezing temperature is -20°C to -30°C.

[0051] In the third step, the freezing time is 20 hours, and the thawing is carried out at room temperature.

[0052] In the third step, the uniform dispersion refers to ultrasonic dispersion of the secondary mixed liquid, and the dispersion time is 30 minutes.

[0053] In the third step, after obtaining the primary mixed solution, the mixture is allowed to stand for defoaming, and then the Fe3O4-CaO2 nanoparticles are added;

[0054] At the same time, before the secondary mixed liquid is introduced into the mold, the uniformly dispersed secondary mixed liquid is first allowed to stand and defoam.

[0055] In the first step, the temperature of step A is 60°C, and the temperature of step B is 90°C.

[0056] In the first step, the mass percentage concentration of PVA in the PVA solution is 10%;

[0057] In the second step, the mass percentage concentration of CMCS in the CMCS solution is 5%;

[0058] In the third step, the mass ratio of the PVA solution in the primary mixed solution is 50%.

[0059] In the first step, the beaker was not stirred during the entire process from the start of water bath heating to the obvious swelling of the PVA.

[0060] In the third step, the Fe3O4-CaO2 nanoparticles refer to composite particles formed by physically binding Fe3O4 and CaO2 by HA.

[0061] A magnetic self-oxygenating hydrogel dressing is a dressing prepared by the method for preparing the magnetic self-oxygenating hydrogel dressing.

[0062] The supplementary technical features of the present invention are as follows:

[0063] In the present invention, PVA refers to polyvinyl alcohol, CMCS refers to carboxymethyl chitosan, and HA refers to hyaluronic acid.

[0064] The basic purpose of this invention is to provide dissolved oxygen to the wound to promote angiogenesis at the wound site and improve wound healing. The main functions of oxygen in the wound recovery process include:

[0065] 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 in tissue cells throughout the body, excessive oxygen partial pressure will produce excessive ROS, causing lipid peroxidation in the body, damaging tissues and organs, and causing many adverse reactions to patients. Local oxygen therapy can provide appropriate oxygen partial pressure to the wound, promote wound healing by regulating oxygen receptors, and avoid the occurrence of systemic complications.

[0066] Anti-infection effect: The bactericidal effect of oxygen is mainly to increase the activity of white blood cells, kill cells and necrotic tissue, thereby inhibiting bacterial growth and accelerating wound healing;

[0067] Promote cell growth: Wound healing mainly relies on the generation of fibroblasts, the synthesis of collagen cells, and the 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, as well as promote energy metabolism and the expression of various growth factors.

[0068] The role of promoting microcirculation: Tissue edema and blood stasis can lead to microcirculation disorders, which prevent local tissues from obtaining the necessary nutrients and are an important cause of non-healing wounds. Local oxygen therapy can effectively reduce tissue edema and is beneficial to the normal growth of endothelial cells and capillaries.

[0069] Example 1:

[0070] A method for preparing a magnetic self-oxygenating hydrogel dressing, comprising the following steps:

[0071] Step 1: First, add PVA to a beaker, then add water, and then seal the beaker. Then heat them together in a water bath until they reach Temperature A (preferably 60°C), then keep them warm until the PVA swells significantly, then heat them to Temperature B (preferably 90°C), and then, at Temperature B, magnetically stir the beaker until the PVA is fully dissolved to obtain a paste-like PVA solution with a mass percentage concentration of 8%-10% in the solution.

[0072] Step 2: First, add powdered CMCS into a beaker, then add water, seal the beaker, and then stir the beaker magnetically until the CMCS is fully dissolved to obtain a CMCS solution with a mass percentage concentration of CMCS in the solution of 5% to 8%;

[0073] Step 3: First, the PVA solution and 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 to obtain a secondary mixed solution, in which the mass of the Fe3O4-CaO2 nanoparticles is 1%-5% of the primary mixed solution. Then, the evenly dispersed secondary mixed solution is introduced into a mold, and the mold is sealed, then frozen, and then thawed. This freezing and thawing process is repeated 6-8 times, and then the seal of the mold is removed to obtain the magnetic self-oxygenating hydrogel dressing.

[0074] A magnetic self-oxygenating hydrogel dressing is a dressing prepared by the method for preparing the magnetic self-oxygenating hydrogel dressing.

[0075] like Figure 1 As shown in FIG, this figure is a SEM image of the surface of the magnetic self-oxygenating hydrogel dressing of the present invention at a resolution of 150 μm. The figure shows a clear network structure, which is a multiple honeycomb structure interlaced inside and outside.

[0076] like Figure 2 As shown in the figure, this figure is a schematic diagram of the double network structure of the magnetic self-oxygenating hydrogel dressing of the present invention. In the figure, the green lines are the molecular chains of CMCS, the yellow dots are the points where CMCS contacts each other during the formation of the hydrogel, the black lines are the molecular chains of PVP, and the red dots are the points where PVP contacts each other during the formation of the hydrogel.

[0077] After obtaining the magnetic self-oxygenating hydrogel dressing, if it is not needed immediately, the self-oxygenating hydrogel needs to be frozen first until the water contained inside it is frozen, and then it can be stored. At this time, the water in the self-oxygenating hydrogel has been frozen into ice, the molecular thermal motion has basically stopped, and it will basically no longer react.

[0078] Example 2:

[0079] The basic content is the same as Example 1, except that:

[0080] In the third step, the freezing temperature is -20°C to -30°C, the freezing time is 20 hours, and the thawing is carried out at room temperature.

[0081] Example 3:

[0082] The basic content is the same as Example 1, except that:

[0083] In the first step, the mass percentage concentration of PVA in the PVA solution is 10%;

[0084] In the second step, the mass percentage concentration of CMCS in the CMCS solution is 5%;

[0085] In the third step, the mass ratio of the PVA solution in the primary mixed solution is 50%.

[0086] Example 4:

[0087] The basic content is the same as Example 1, except that:

[0088] In the first step, accurately weigh 5g of polyvinyl alcohol (PVA) and add 45ml of sterile ultrapure water to a clean beaker. Heat the mixture to 60°C in a constant-temperature water bath without stirring. After 1 hour, the PVA will noticeably swell. Then, heat the constant-temperature water bath to 90°C, seal the beaker, and stir repeatedly for approximately 3 hours to fully dissolve the PVA. The PVA will dissolve completely into a paste, with no visible particulate matter in the solution, to obtain a 10% by weight aqueous solution of PVA.

[0089] In the second step, 20 g of carboxymethyl chitosan (CMCS) powder was weighed into a clean beaker, and then a 5% by mass carboxymethyl chitosan solution was prepared. The solution was stirred on a magnetic stirrer for 1 h to fully dissolve the carboxymethyl chitosan powder to obtain a CMCS solution.

[0090] In the third step, the PVA aqueous solution and the CMCS solution are mixed in a mass ratio of 5:5, and then allowed to stand for defoaming to obtain a primary mixed solution.

[0091] The static defoaming means that since the solution is a relatively thick colloid, air will enter the liquid during stirring, generating bubbles. Therefore, this design allows the stirred liquid to 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.

[0092] Example 5:

[0093] The basic content is the same as Example 1, except that:

[0094] In the third step, 0.5 g of Fe3O4-CaO2 nanoparticles are first added to 50 ml of the primary mixture, which is then ultrasonically treated for 30 minutes and then allowed to stand for defoaming to obtain a secondary mixture. The secondary mixture is then introduced into a mold, and the mold is sealed and frozen at -20°C. The mold is then taken out and thawed at room temperature for 8 hours to thaw. This freezing and thawing process is repeated 7 times, and then the mold seal is removed to obtain the PVA-CMCS-based magnetic self-oxygenating hydrogel.

[0095] Example 6:

[0096] The basic content is the same as Example 5, except that:

[0097] In the third 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, then ultrasonically dissolved for 10 minutes, and then placed on 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. When the solution is observed to gradually turn milky white, stirring is stopped, and then centrifuged at 10000rpm for 10 minutes using a centrifuge, and then the solid dressing is collected, and then the solid dressing is dissolved in 20ml of anhydrous ethanol and stirred for 24 hours. Finally, it is centrifuged at 12000rpm for 10 minutes to obtain Fe3O4-CaO2 nanoparticles.

[0098] 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 in the present invention should be included in the protection scope recorded in the claims.

Claims

1. A method for preparing a magnetic self-oxygenating hydrogel dressing, characterized in that: The preparation method comprises the following steps: Step 1: First add PVA into a beaker, then add water, then seal the beaker, and heat them together in a water bath until they reach Temperature A, then keep them warm until the PVA swells significantly, then heat them to Temperature B, and then magnetically stir the beaker at Temperature B until the PVA is fully dissolved to obtain a paste-like PVA solution with a mass percentage concentration of 8%-10% in the solution. Step 2: First, add powdered CMCS into a beaker, then add water, seal the beaker, and then stir the beaker magnetically until the CMCS is fully dissolved to obtain a CMCS solution with a mass percentage concentration of CMCS in the solution of 5% to 8%; Step 3: First, the PVA solution and 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 to obtain a secondary mixed solution, in which the mass of the Fe3O4-CaO2 nanoparticles is 1%-5% of the primary mixed solution. Then, the evenly dispersed secondary mixed solution is introduced into a mold, and the mold is sealed, then frozen, and then thawed. This freezing and thawing process is repeated 6-8 times, and then the seal of the mold is removed to obtain the magnetic self-oxygenating hydrogel dressing.

2. The method for preparing a magnetic self-oxygenating hydrogel dressing according to claim 1, characterized in that: In the third step, the freezing temperature is -20°C to -30°C.

3. The method for preparing a magnetic self-oxygenating hydrogel dressing according to claim 2, characterized in that: In the third step, the freezing time is 20 hours, and the thawing is carried out at room temperature.

4. The method for preparing a magnetic self-oxygenating hydrogel dressing according to claim 1, 2 or 3, characterized in that: In the third step, the uniform dispersion refers to ultrasonic dispersion of the secondary mixed liquid, and the dispersion time is 30 minutes.

5. The method for preparing a magnetic self-oxygenating hydrogel dressing according to claim 1, 2 or 3, characterized in that: In the third step, after obtaining the primary mixed solution, the mixture is allowed to stand for defoaming, and then the Fe3O4-CaO2 nanoparticles are added; At the same time, before the secondary mixed liquid is introduced into the mold, the uniformly dispersed secondary mixed liquid is first allowed to stand and defoam.

6. The method for preparing a magnetic self-oxygenating hydrogel dressing according to claim 1, 2 or 3, characterized in that: In the first step, the temperature of step A is 60°C, and the temperature of step B is 90°C.

7. The method for preparing a magnetic self-oxygenating hydrogel dressing according to claim 1, 2 or 3, characterized in that: In the first step, the mass percentage concentration of PVA in the PVA solution is 10%; In the second step, the mass percentage concentration of CMCS in the CMCS solution is 5%; In the third step, the mass ratio of the PVA solution in the primary mixed solution is 50%.

8. The method for preparing a magnetic self-oxygenating hydrogel dressing according to claim 1, 2 or 3, characterized in that: In the first step, the beaker was not stirred during the entire process from the start of water bath heating to the obvious swelling of the PVA.

9. The method for preparing a magnetic self-oxygenating hydrogel dressing according to claim 1, 2 or 3, characterized in that: In the third step, the Fe3O4-CaO2 nanoparticles refer to composite particles formed by physically binding Fe3O4 and CaO2 with hyaluronic acid.

10. A magnetic self-oxygenating hydrogel dressing, characterized by: The magnetic self-oxygenating hydrogel dressing is a product of the preparation method of the magnetic self-oxygenating hydrogel dressing according to claim 1, 2 or 3.

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