A dressing for the treatment of atopic dermatitis and a method of making and using the same

Abstract

This invention discloses a dressing for treating atopic dermatitis, its preparation method, and its application, relating to the field of medical materials technology. The dressing for treating atopic dermatitis is composed of PH powder and Que@CD nanoparticles. The technical solution provided by this invention utilizes amino-rich ε-polylysine and NHS ester-modified hyaluronic acid for rapid cross-linking via an amidation reaction in a moist environment, forming a three-dimensional gel network encapsulating Que@CD nanoparticles. Utilizing the water solubility of Que@CD, quercetin can be rapidly released to relieve itching. Simultaneously, it exerts anti-inflammatory and antioxidant effects by scavenging excess reactive oxygen species, alleviating oxidative stress, regulating the immune microenvironment, and inhibiting the release of inflammatory factors. Therefore, the dressing proposed in this invention possesses in-situ gelling properties and drug burst release capability, enabling it to closely adhere to irregular skin wounds and comprehensively exert antioxidant, anti-inflammatory, and immunomodulatory effects.

Description

Technical Field

[0001] This invention relates to the field of medical materials technology, and in particular to a dressing for treating atopic dermatitis, its preparation method, and its application. Background Technology

[0002] Atopic dermatitis (AD) is a common chronic inflammatory skin disease. Clinically, atopic dermatitis manifests as dry skin, itchy papules, epidermal scratch marks, and crusted lesions, and is more prone to Staphylococcus aureus infection. Traditional treatment mainly relies on emollients and moisturizers to relieve symptoms. In the acute phase, corticosteroids and antihistamines are commonly used to control inflammation, but long-term use may lead to adverse reactions such as hyperglycemia and Cushing's syndrome. Antibiotics can be used for secondary Staphylococcus aureus infections, but long-term oral administration may disrupt the intestinal flora, inducing skin allergies, rashes, itching, and even asthma and anaphylactic shock. Summary of the Invention

[0003] The main objective of this invention is to provide a dressing for treating atopic dermatitis, its preparation method, and its application, aiming to achieve therapeutic function while reducing the possibility of inducing side effects.

[0004] To achieve the above objectives, the present invention proposes a dressing for treating atopic dermatitis, which is composed of PH powder and Que@CD nanoparticles.

[0005] In one embodiment, the PH powder is a uniform mixture of ε-polylysine and hyaluronic acid modified with activated ester.

[0006] In one embodiment, the activated ester-modified hyaluronic acid is N-hydroxysuccinimide ester-modified hyaluronic acid.

[0007] In one embodiment, the Que@CD nanoparticles are cyclodextrin-based metal-organic frameworks loaded with quercetin.

[0008] In one embodiment, the cyclodextrin-based metal-organic framework is a water-soluble metal-organic framework formed by the self-assembly of γ-cyclodextrin and potassium ions.

[0009] The present invention also proposes a method for preparing a dressing for treating atopic dermatitis, comprising the following steps: S1: Preparation of cyclodextrin-based metal-organic frameworks γ-cyclodextrin and potassium hydroxide were dissolved in distilled water, methanol was added, and the mixture was sealed in a glass container. The mixture was then irradiated under microwave to obtain a clear solution. Subsequently, a methanol solution containing PEG 20000 was added, the mixture was allowed to stand, the crystals were collected by centrifugation, washed with ethanol, and freeze-dried to obtain CD-MOF for later use. S2: Preparation of quercetin-loaded cyclodextrin-based metal-organic frameworks The quercetin ethanol solution was mixed and stirred with the CD-MOF obtained in step S1, the product was recovered by centrifugation, washed with ethanol and freeze-dried to obtain Que@CD; S3: Preparation of NHS-grafted hyaluronic acid Hyaluronic acid was dissolved in a mixed solution of dimethyl sulfoxide and MES buffer, the pH was adjusted to 6, EDC was added and stirred, followed by NHS. The reaction was carried out at room temperature in the dark. After the reaction was completed, pre-cooled ethanol was added to precipitate the product, the precipitate was collected by centrifugation, washed once with anhydrous ethanol, and finally freeze-dried to obtain HA-NHS. S4: Preparation of powdered dressing containing Que@CD ε-polylysine and HA-NHS were uniformly mixed to obtain PH powder dressing. Que@CD nanoparticles were added to the PH powder dressing to prepare the dressing Que@CD@PH for the treatment of atopic dermatitis.

[0010] In one embodiment, the microwave conditions in step S1 are 50°C and 100 W.

[0011] This invention also proposes the application of PH powder and Que@CD nanoparticles in the preparation of drugs for treating atopic dermatitis.

[0012] The present invention also proposes the application of the above preparation method in the preparation of drugs for treating atopic dermatitis.

[0013] The technical solution of this invention utilizes amino-rich ε-polylysine and NHS ester-modified hyaluronic acid for rapid cross-linking via an amidation reaction in a moist environment to form a three-dimensional gel network encapsulating Que@CD nanoparticles. Leveraging the water solubility of Que@CD, quercetin can be rapidly released to relieve itching. Simultaneously, it exerts anti-inflammatory and antioxidant effects by scavenging excess reactive oxygen species, alleviating oxidative stress, regulating the immune microenvironment, and inhibiting the release of inflammatory factors. Therefore, the dressing proposed in this invention possesses in-situ gelling properties and drug burst release capability, enabling it to closely adhere to irregular skin wounds and comprehensively exert antioxidant, anti-inflammatory, and immunomodulatory effects. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a simplified diagram of the preparation route for the dressing proposed in this invention; Figure 2These are actual photographs of the gelation process in Example 1 of the present invention; Figure 3 These are actual photographs of the adhesion performance of Embodiment 1 of the present invention; Figure 4 This is a diagram showing the drug release behavior results of Example 1 of the present invention; Figure 5 The graphs show the in vitro antioxidant properties of Example 1 and Comparative Example 1 of this invention. Figure 6 The diagram shows the in vitro antibacterial properties of Example 1 and Comparative Examples 1 and 2 of the present invention.

[0016] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0019] Atopic dermatitis (AD) is a complex, chronic, relapsing, inflammatory skin disease with an increasing incidence worldwide. Its clinical manifestations are characteristic, including persistent dry skin, intense itching, and polymorphic lesions such as papules and plaques, often accompanied by epidermal peeling, exudation, crusting, and lichenification due to scratching. Severe disruption of the skin barrier function makes the patient's skin more susceptible to external irritants and allergens, and also significantly increases the risk of secondary infections, with Staphylococcus aureus colonization and infection being particularly common, further exacerbating inflammation and worsening the condition.

[0020] In existing clinical treatment systems, treatment plans often follow a stepwise approach. Basic treatment relies on emollients and moisturizers to repair the skin barrier and relieve dryness, but this has limited effectiveness in controlling inflammation in moderate to severe cases. During the acute phase or when symptoms worsen, topical corticosteroids and antibiotics remain first-line anti-inflammatory drugs, while systemic antihistamines are used to relieve itching. However, long-term or high-potency use of corticosteroids may cause adverse reactions such as local skin atrophy and telangiectasia, and systemic use may lead to endocrine disorders, manifesting as hyperglycemia, hypertension, Cushing's syndrome, and hypothalamic-pituitary-adrenal axis suppression. Long-term or inappropriate use of antibiotics, while fighting infection, may disrupt the body's microecological balance, potentially inducing drug allergic reactions and increasing the risk of bacterial resistance, posing risks to subsequent treatment.

[0021] To overcome these limitations, research in the field of biomaterials has turned its attention to hydrogels. Their high-water-content three-dimensional network structure provides a long-lasting moist microenvironment, effectively relieving dryness and itching, and promoting epithelial regeneration. Meanwhile, the natural product quercetin, due to its excellent antioxidant, broad-spectrum antibacterial, and immunomodulatory properties, shows potential as an ideal therapeutic molecule, especially suitable for Alzheimer's disease (AD), which is closely related to oxidative stress and immune dysregulation. However, quercetin has extremely poor water solubility and low chemical stability, resulting in low percutaneous penetration and absorption efficiency, and its bioavailability is far from meeting clinical treatment requirements. To improve its delivery, advanced nanocarriers such as metal-organic frameworks (MOFs) have been extensively studied, as they can effectively encapsulate and protect hydrophobic drugs. However, many traditional MOFs contain non-degradable metal ions, posing potential biosafety concerns and long-term in vivo accumulation toxicity, limiting their clinical translation prospects.

[0022] Therefore, both clinical practice and materials science point to a clear unmet need: the urgent need to develop a novel dressing. An ideal dressing should possess both excellent moisturizing and repairing capabilities and efficient and safe drug delivery. It needs to integrate multifunctional active ingredients similar to quercetin and achieve controlled release through a biocompatible carrier, thereby synergistically exerting a comprehensive therapeutic effect of anti-inflammation, antibacterial, antioxidant, and antipruritic properties. Simultaneously, it should fundamentally avoid the core defects of traditional treatment modalities such as hormone dependence, antibiotic abuse, and metal toxicity, ultimately providing a more effective, safer, and easier-to-use breakthrough treatment option for patients with atopic dermatitis.

[0023] Therefore, this invention proposes a dressing for treating atopic dermatitis, composed of PH powder and Que@CD nanoparticles; wherein the mass ratio of PH powder to Que@CD nanoparticles is 99:1. The PH powder can rapidly form a gel, thereby moisturizing and repairing the affected area; while the Que@CD nanoparticles rapidly release medication, providing active treatment to the affected area; the PH powder and Que@CD nanoparticles work synergistically to treat the affected area; the mass ratio ensures that the main body of the dressing is a dry powder, facilitating long-term storage and transportation, while guaranteeing a sufficient load of active ingredients. Furthermore, the powder form facilitates measurement and even application to irregular wounds. Upon contact with skin exudate or moisture, the PH powder rapidly forms a gel to fix the Que@CD, achieving in-situ treatment.

[0024] In this invention, the PH powder is uniformly mixed from ε-polylysine and hyaluronic acid modified with activated esters, and the mass ratio of ε-polylysine to hyaluronic acid modified with activated esters is 1:2, thereby enabling the PH powder to achieve rapid in-situ cross-linking. ε-polylysine is rich in amino groups, and hyaluronic acid modified with activated esters provides activated ester groups. Upon contact with water, the two can rapidly undergo an efficient amidation reaction, achieving an instant transformation from powder to hydrogel, which adheres closely to the wound surface. The mass ratio of the two components gives the hydrogel suitable mechanical strength, adhesion, and swelling rate, which is an optimal ratio for the gel network. At this ratio, the moisturizing ability of hyaluronic acid and the antibacterial and repair-promoting abilities of ε-polylysine can achieve a good synergistic effect. In addition, both ε-polylysine and hyaluronic acid are biocompatible natural or biomimetic polymers, avoiding the potential toxicity of synthetic cross-linking agents.

[0025] In this invention, the activated ester-modified hyaluronic acid is N-hydroxysuccinimide ester-modified hyaluronic acid, i.e., HA-NHS; the activated ester is NHS ester, i.e., N-hydroxysuccinimide; the reaction conditions of NHS ester and primary amine derived from ε-polylysine are mild, with a pH close to the physiological pH, fast rate, and high selectivity, ensuring efficient and specific gelation in a moist skin environment and reducing side reactions; moreover, NHS is a mature and readily available biochemical reagent, and its EDC / NHS coupling process for modifying hyaluronic acid is standardized and controllable, which is conducive to the large-scale and standardized production of this dressing.

[0026] Furthermore, in this invention, the Que@CD nanoparticles are cyclodextrin-based metal-organic frameworks loaded with quercetin. These cyclodextrin-based metal-organic frameworks are water-soluble metal-organic frameworks formed by the self-assembly of γ-cyclodextrin and potassium ions. The cyclodextrin-based metal-organic framework, i.e., CD-MOF, possesses a porous structure, which allows for the encapsulation of hydrophobic quercetin, transforming it into a nanoscale water-soluble complex, significantly improving the drug's dispersibility and apparent solubility. Moreover, the framework structure of CD-MOF can protect quercetin from... It is susceptible to degradation by light and oxidation, and the drug can be released in a controlled manner through the dissociation of the framework. At the same time, the MOF is constructed using biocompatible γ-cyclodextrin and potassium ions, which are essential elements for the human body. This framework can be degraded into safe components in vivo, completely avoiding the long-term biotoxicity problems of traditional MOFs containing zinc and copper ions. Furthermore, the CD-MOF in this invention has good water solubility, which is a prerequisite for the rapid release of quercetin from Que@CD in a moist gel environment and a key advantage that distinguishes it from most traditional MOFs that are insoluble in water.

[0027] In the Que@CD nanoparticles of this invention, the mass ratio of quercetin to cyclodextrin-based metal-organic framework is 1:1.5. This ratio can ensure high drug loading efficiency without destroying the crystal structure stability of CD-MOF, ensuring that the drug can be rapidly released in the early stage to quickly relieve itching and inflammation. Furthermore, the Que@CD nanoparticles prepared under this ratio have uniform size, good dispersibility, and are easy to mix uniformly with pH powder.

[0028] The present invention also provides a method for preparing the above-mentioned dressing for treating atopic dermatitis, comprising the following steps: S1: Preparation of cyclodextrin-based metal-organic frameworks γ-cyclodextrin and potassium hydroxide were dissolved in distilled water, methanol was added, and the mixture was sealed in a glass container. The mixture was then irradiated under microwave conditions of 50°C and 100 W to obtain a clear solution. Subsequently, a methanol solution containing PEG 20000 was added, the mixture was allowed to stand, the crystals were collected by centrifugation, washed with ethanol, and freeze-dried at -30°C for 24 hours to obtain CD-MOF for later use. S2: Preparation of quercetin-loaded cyclodextrin-based metal-organic frameworks The quercetin ethanol solution was mixed with the CD-MOF obtained in step S1 and stirred for 24 hours. The product was then recovered by centrifugation, washed with ethanol, and freeze-dried at -30°C for 24 hours to obtain Que@CD. S3: Preparation of NHS-grafted hyaluronic acid Hyaluronic acid was dissolved in a mixed solution of dimethyl sulfoxide and MES buffer at a volume ratio of 4:1. The pH was adjusted to 6 with dilute hydrochloric acid. EDC was added and stirred for 30 min to activate the carboxyl groups of hyaluronic acid. Then NHS was added and the reaction was stirred at room temperature in the dark for 3 h. After the reaction was completed, pre-cooled ethanol was added to precipitate the product. The precipitate was collected by centrifugation, washed once with anhydrous ethanol, and finally freeze-dried to obtain HA-NHS. S4: Preparation of powdered dressing containing Que@CD ε-polylysine and HA-NHS were uniformly mixed to obtain PH powder dressing. Que@CD nanoparticles were added to the PH powder dressing to prepare the dressing Que@CD@PH for the treatment of atopic dermatitis.

[0029] The principle of the dressing proposed in this invention is explained as follows: The nanoparticles use cyclodextrin-based metal-organic framework nanoparticles (CD-MOFs) as carriers, and their porous structure loads the active ingredient quercetin. CD-MOFs are a type of metal-organic framework material with high specific surface area and an ordered porous structure. CD-MOFs can be degraded in vivo into biosafe components γ-cyclodextrin and potassium ions, avoiding the toxicity caused by the accumulation of metal ions. Their water solubility facilitates the controlled and rapid release of the loaded quercetin.

[0030] Quercetin possesses dual antioxidant and antibacterial activities, capable of regulating the immune microenvironment at the site of inflammation and accelerating wound healing; its inherent antipruritic properties can relieve chronic itching; nanoparticles achieve efficient loading of quercetin through the porous adsorption of MOFs; and with the help of the water solubility of CD-MOFs, controllable and rapid release of quercetin is achieved to quickly relieve itching, thus achieving highly efficient anti-inflammatory and antioxidant effects at the target site.

[0031] The powder matrix is ​​composed of ε-polylysine and hyaluronic acid modified with NHS ester. ε-polylysine, as a natural cationic antimicrobial peptide, is less likely to induce bacterial resistance compared to traditional antibiotics. Hyaluronic acid is a natural polymer with excellent biocompatibility, and its moisturizing properties can significantly relieve skin dryness and promote barrier repair. After modification with NHS ester, its carboxyl groups can rapidly crosslink with amino-rich ε-polylysine through an amidation reaction in a moist environment, forming a three-dimensional gel network that encapsulates nanoparticles in situ. This network continuously acts on the inflamed area, exerting long-lasting antibacterial, skin dryness-relieving, and barrier repair-promoting effects. The powder matrix adheres to irregular wounds in situ, forming effective physical protection. The rapid drug release characteristics of the nanoparticles simultaneously exert antipruritic, antioxidant, and antibacterial effects, constructing an AD synergistic treatment dressing system that integrates antipruritic, antibacterial, and anti-inflammatory functions.

[0032] The present invention will be further described below with reference to embodiments and comparative examples: Example 1: S1: Preparation of cyclodextrin-based metal-organic frameworks Weigh 342 mg of γ-cyclodextrin and 112 mg of potassium hydroxide and dissolve them in 10 mL of distilled water. Quickly add 6 mL of methanol and seal the container in a glass container. Treat the solution at 50 °C and 100 W microwave irradiation for 10 min to obtain a clear solution. Then quickly add 16 mL of methanol solution containing PEG 20000 (concentration 8 mg / mL). After standing for 1 h, collect the crystals by centrifugation at 13000 rpm, wash with ethanol, and freeze-dry at -30 °C for 24 h to obtain CD-MOF for later use. S2: Preparation of quercetin-loaded cyclodextrin-based metal-organic frameworks 10 mL of 2 mg / mL quercetin ethanol solution was mixed with 30 mg CD-MOF and stirred. The product was recovered by centrifugation at 13000 rpm, washed with ethanol, and then freeze-dried at -30℃ for 24 hours to obtain Que@CD nanoparticles. S3: Preparation of NHS-grafted hyaluronic acid 0.38 g of hyaluronic acid was dissolved in a mixture of dimethyl sulfoxide (DMSO) and MES buffer (MES buffer volume ratio 4:1). The pH was adjusted to 6 with dilute hydrochloric acid, and 0.62 g of EDC was added and stirred for 30 min. Then, 0.46 g of NHS was added, and the reaction was carried out at room temperature in the dark with stirring for 3 h. After the reaction was completed, a large amount of pre-cooled ethanol was added to precipitate the product. The precipitate was collected by centrifugation at 13,000 rpm, washed once with anhydrous ethanol, and finally freeze-dried to obtain HA-NHS.

[0033] S4: Preparation of powdered dressing containing Que@CD ε-polylysine and HA-NHS were uniformly mixed at a mass ratio of 1:2 to obtain PH powder. The PH powder was then uniformly mixed with Que@CD nanoparticles at a mass ratio of 99:1 to obtain the final dressing, Que@CD@PH.

[0034] Comparative Example 1: Based on Example 1, the dressing is prepared according to the following steps. S1: Preparation of cyclodextrin-based metal-organic frameworks Weigh 342 mg of γ-cyclodextrin and 112 mg of potassium hydroxide and dissolve them in 10 mL of distilled water. Quickly add 6 mL of methanol and seal the container in a glass container. Treat the solution at 50 °C and 100 W microwave irradiation for 10 min to obtain a clear solution. Then quickly add 16 mL of methanol solution containing PEG 20000, let stand for 1 h, centrifuge to collect the crystals, wash with ethanol, and freeze-dry to obtain CD-MOF for later use. S2: Preparation of NHS-grafted hyaluronic acid 0.38 g of hyaluronic acid was dissolved in a mixture of dimethyl sulfoxide and MES buffer at a volume ratio of 4:1. The pH was adjusted to 6, and 0.62 g of EDC was added and stirred for 30 min. Then, 0.46 g of NHS was added, and the reaction was carried out at room temperature in the dark with stirring for 3 h. After the reaction was completed, a large amount of pre-cooled ethanol was added to precipitate the product. The precipitate was collected by centrifugation, washed once with anhydrous ethanol, and finally freeze-dried.

[0035] S3: Preparation of powdered dressing containing CD-MOF ε-polylysine and HA-NHS were uniformly mixed at a mass ratio of 1:2 to obtain PH powder. The PH powder was then uniformly mixed with CD-MOF nanoparticles at a mass ratio of 99:1 to obtain the final dressing.

[0036] Comparative Example 2: Based on Example 1, the dressing is prepared according to the following steps. S1: Preparation of cyclodextrin-based metal-organic frameworks Weigh 342 mg of γ-cyclodextrin and 112 mg of potassium hydroxide and dissolve them in 10 mL of distilled water. Quickly add 6 mL of methanol and seal the container in a glass container. Treat the solution at 50 °C and 100 W microwave irradiation for 10 min to obtain a clear solution. Then quickly add 16 mL of methanol solution containing PEG 20000, let stand for 1 h, centrifuge to collect the crystals, wash with ethanol, and freeze-dry to obtain CD-MOF for later use. S2: Preparation of quercetin-loaded cyclodextrin-based metal-organic frameworks 10 mL of 2 mg / mL quercetin ethanol solution was mixed with 30 mg CD-MOF, stirred, centrifuged to recover the product, washed with ethanol and freeze-dried to obtain Que@CD; The performance evaluation of the novel multifunctional powdered skin dressing of the present invention was conducted using the powdered skin dressing described in the examples as the research object. The specific experimental conditions are as follows: 1. Testing of the adhesive properties and bonding performance of powdered dressings 10 mg of Example 1 was added to 50 μL of deionized water and allowed to stand; the adhesive ability of the absorbent Example 1 to wood, plastic, glass, rubber, pigskin and iron at 25°C was tested.

[0037] Experimental results: such as Figure 1 As can be seen, in Example 1 in the test tube, the ε-polylysine contained therein undergoes an amidation reaction with NHS ester, rapidly cross-linking to form a three-dimensional network gel, which does not flow when inverted. Adhesion test results are as follows. Figure 2 As can be seen, Example 1 can adhere firmly to pigskin and various materials, including metal, glass, rubber, wood, and plastic. This demonstrates the successful preparation of a novel multifunctional powdered skin dressing capable of in-situ gelation and possessing excellent adhesive properties.

[0038] 2. Quercetin release behavior test Example 1 was immersed in 5 mL of PBST solution containing 0.5% Tween 80 and placed in a shaking incubator (37°C, 100 rpm / min). At specified time points, 2 mL of solution was extracted and replenished with 2 mL of fresh buffer. The release of quercetin was determined using a UV-Vis spectrophotometer at 370 nm, and its cumulative drug release was calculated to analyze the controllable and rapid drug release achieved by the multifunctional powdered skin dressing of the present invention.

[0039] Experimental results: such as Figure 3 It can be seen that the release rate of quercetin exceeded 80% at 5 min and 99.31% at 3 h, which is almost complete. This shows that Example 1 has a controllable and rapid release effect, and the rapid release of quercetin helps to exert its anti-inflammatory and antipruritic effects.

[0040] 3. In vitro antioxidant performance test The antioxidant capacity of Example 1 and Comparative Example 1 was evaluated using diphenylpicrylhydrazine (DPPH) reagent and 2,2-azido-bis(3-ethylhexylamine-3-benzothiazole-6-sulfonic acid) diammonium salt (ABTS) reagent. DPPH working solution (2000 μL) was added to a 24-well plate, followed by the addition of a negative control group (deionized water), a positive control group (ascorbic acid), Example 1, and Comparative Example 1, respectively. After co-culturing for 30 minutes, the antioxidant effect was determined by measuring the absorbance of the supernatant at 517 nm. ABTS working solution (2000 μL) was treated in the same manner, and the antioxidant effect was determined by measuring the absorbance of the supernatant at 734 nm.

[0041] Experimental results: Figure 5 (A) and Figure 5(D) As can be seen, the Example 1 group exhibited higher antioxidant performance, and all of them were higher than those of Comparative Example 1. Figure 5 (B) and Figure 5 (E) As shown in the photograph, Comparative Example 1 exhibits some scavenging effect on DPPH and ABTS free radicals, but both are significantly lower than those in Example 1. Figure 5 (C) and Figure 5 (F) As can be seen from the calculations, the DPPH free radical scavenging abilities of Comparative Example 1 and Example 1 are 9.45±3.05% and 86.05±2.05%, respectively; the ABTS free radical scavenging abilities are 52.75±3.65% and 95.20±0.72%, respectively. The above experimental results show that Example 1 has excellent antioxidant activity.

[0042] 4. Antibacterial performance test During the course of atopic dermatitis, persistent scratching can damage the skin barrier, making patients susceptible to bacterial infections. This experiment used typical bacterial representatives, *Escherichia coli* and *Staphylococcus aureus*, as test subjects. These were mixed thoroughly with a blank control (phosphate buffer, pH 7.4), Example 1, Comparative Example 1, and Comparative Example 2, and then incubated at 37 °C with shaking for 24 hours. The resulting bacterial solutions were then evenly spread onto agar plates and incubated at 37 °C for 24 hours. The antibacterial effect of each component was determined the following day by observing the morphology and number of colonies on the agar plates.

[0043] Experimental results: The antibacterial performance was evaluated using the colony counting method, such as... Figure 6 As shown, Example 1 significantly inhibited the growth of Escherichia coli and Staphylococcus aureus. This indicates that the gel of Example 1 has excellent antibacterial properties.

[0044] In summary, the novel multifunctional powdered skin dressing of this invention provides the material with multiple synergistic advantages: the gel formed by the powder matrix in a moist environment firmly adheres to the skin to provide a physical barrier and maintain a moist environment, promoting skin barrier repair; the cyclodextrin-based metal-organic framework in the nanoparticles, with its porous properties, enables efficient loading and controlled rapid release of the drug quercetin, achieving highly effective antipruritic, anti-inflammatory, and antibacterial effects. Therefore, this novel multifunctional powdered skin dressing, through its unique design, solves the core challenges in the treatment of atopic dermatitis, such as dry skin, low drug bioavailability, metal ion toxicity of drug delivery carriers, and bacterial resistance, providing an efficient, precise, and safe treatment strategy for atopic dermatitis.

[0045] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A dressing for treating atopic dermatitis, characterized in that, The dressing is composed of PH powder and Que@CD nanoparticles.

2. The dressing as described in claim 1, characterized in that, The PH powder is a uniform mixture of ε-polylysine and hyaluronic acid modified with activated ester.

3. The dressing as described in claim 2, characterized in that, The activated ester-modified hyaluronic acid is N-hydroxysuccinimide ester-modified hyaluronic acid.

4. The dressing as described in claim 1, characterized in that, The Que@CD nanoparticles are cyclodextrin-based metal-organic frameworks loaded with quercetin.

5. The dressing as described in claim 4, characterized in that, The cyclodextrin-based metal-organic framework is a water-soluble metal-organic framework formed by the self-assembly of γ-cyclodextrin and potassium ions.

6. A method for preparing a dressing for treating atopic dermatitis as described in any one of claims 1-5, comprising the following steps: S1: Preparation of cyclodextrin-based metal-organic frameworks γ-cyclodextrin and potassium hydroxide were dissolved in distilled water, methanol was added, and the mixture was sealed in a glass container. The mixture was then irradiated under microwave to obtain a clear solution. Subsequently, a methanol solution containing PEG 20000 was added, the mixture was allowed to stand, the crystals were collected by centrifugation, washed with ethanol, and freeze-dried to obtain CD-MOF for later use. S2: Preparation of quercetin-loaded cyclodextrin-based metal-organic frameworks The quercetin ethanol solution was mixed and stirred with the CD-MOF obtained in step S1, the product was recovered by centrifugation, washed with ethanol and freeze-dried to obtain Que@CD; S3: Preparation of NHS-grafted hyaluronic acid Hyaluronic acid was dissolved in a mixed solution of dimethyl sulfoxide and MES buffer, the pH was adjusted to 6, EDC was added and stirred, followed by NHS. The reaction was carried out at room temperature in the dark. After the reaction was completed, pre-cooled ethanol was added to precipitate the product, the precipitate was collected by centrifugation, washed once with anhydrous ethanol, and finally freeze-dried to obtain HA-NHS. S4: Preparation of powdered dressing containing Que@CD ε-polylysine and HA-NHS were uniformly mixed to obtain PH powder dressing. Que@CD nanoparticles were added to the PH powder dressing to prepare the dressing Que@CD@PH for the treatment of atopic dermatitis.

7. The method for preparing the dressing as described in claim 6, characterized in that, In step S1, the microwave conditions are 50°C and 100 W.

8. Application of PH powder and Que@CD nanoparticles in the preparation of drugs for treating atopic dermatitis.

9. The use of the preparation method according to any one of claims 6 or 7 in the preparation of a drug for treating atopic dermatitis.

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