Hydrogel dressing loaded with fresh tea leaf-derived nanoparticles, and preparation method and application thereof

Abstract

This invention belongs to the field of hydrogel dressing technology, specifically disclosing a hydrogel dressing loaded with fresh tea leaf nanoparticles, its preparation method, and its application. The preparation method includes the following steps: preparing fresh tea leaf nanoparticles; preparing a carboxymethyl chitosan solution; preparing a carboxymethyl chitosan solution containing fresh tea leaf nanoparticles; preparing an oxidized hyaluronic acid solution; and mixing the obtained carboxymethyl chitosan solution containing fresh tea leaf nanoparticles with the oxidized hyaluronic acid solution to obtain the hydrogel dressing loaded with fresh tea leaf nanoparticles. This invention utilizes the above-mentioned hydrogel dressing loaded with fresh tea leaf nanoparticles, its preparation method, and its application. The preparation process is simple and easy to control, and is not limited by problems such as increased antibiotic resistance and frequent dressing changes. It promotes wound healing, eliminates harmful bacteria, effectively resists multidrug-resistant bacterial infections, and simultaneously promotes wound healing and skin regeneration.

Description

Technical Field

[0001] This invention relates to the field of hydrogel dressing technology, and in particular to hydrogel dressings containing fresh tea leaf nanoparticles, their preparation methods, and applications. Background Technology

[0002] Bacterial infection is one of the most common problems encountered in wound healing and skin regeneration. Severe inflammatory responses caused by infection not only significantly increase infection-related complications but also markedly reduce the quality of wound healing. Furthermore, bacterial infections are difficult to treat, require long treatment courses, and are expensive, imposing a significant economic burden on patients and society. Currently, antibiotics are the primary treatment for infected wounds in clinical practice. However, due to drug resistance and the lack of a suitable skin repair microenvironment, the therapeutic effects on both infection control and wound healing are not ideal. Therefore, effectively combating multidrug-resistant bacterial infections while simultaneously promoting infected wound healing and skin regeneration remains a major challenge that urgently needs to be addressed.

[0003] Staphylococcus aureus is one of the most common bacteria that cause wound infections. It can produce a variety of toxins and enzymes that damage tissue and cause inflammatory responses.

[0004] Current methods for treating infected wounds include routine debridement, oral antibiotics, antibacterial dressings, and negative pressure wound therapy. However, these methods are limited by issues such as increasing antibiotic resistance and frequent dressing changes. Therefore, there is a need for a minimally invasive, innovative treatment strategy that promotes drug penetration and achieves long-term effectiveness. Thus, developing a highly effective anti-infective wound dressing is essential. Summary of the Invention

[0005] The purpose of this invention is to provide a hydrogel dressing containing tea-derived nanoparticles, its preparation method, and its application. The hydrogel uses carboxymethyl chitosan and oxidized hyaluronic acid to rapidly crosslink into a gel at room temperature. The preparation process is simple and easy to control. Fresh tea-derived nanoparticles are loaded into the hydrogel, which is not limited by issues such as increased antibiotic resistance or frequent dressing changes. It can slowly and continuously act on infected wounds, achieving the effects of eliminating harmful bacteria, effectively resisting multidrug-resistant bacterial infections, and simultaneously promoting wound healing and skin regeneration.

[0006] To achieve the above objectives, the present invention provides a method for preparing a hydrogel dressing loaded with fresh tea leaf nanoparticles, comprising the following steps:

[0007] S1. Preparation of fresh tea leaf nanoparticles;

[0008] S2. Dissolve carboxymethyl chitosan to obtain a carboxymethyl chitosan solution;

[0009] S3. Mix the obtained carboxymethyl chitosan solution with fresh tea leaf nanoparticles to prepare a carboxymethyl chitosan solution containing fresh tea leaf nanoparticles.

[0010] S4. Dissolve the oxidized hyaluronic acid to obtain an oxidized hyaluronic acid solution;

[0011] S5 mixes the carboxymethyl chitosan solution containing fresh tea-derived nanoparticles with an oxidized hyaluronic acid solution to obtain a hydrogel dressing loaded with fresh tea-derived nanoparticles.

[0012] Preferably, in step S1, the preparation process of fresh tea leaf nanoparticles is as follows: fresh tea leaves and phosphate buffer are mixed and juiced at a power of 200-1000W for at least 2 minutes to completely break the tea leaves. The juice is then squeezed through a 100-200 mesh filter to obtain fresh tea leaf juice. The juice is then centrifuged at a relative centrifugal force of 300g-1800g for 5-15 minutes, at a relative centrifugal force of 2000g-6000g for 15-35 minutes, and at a relative centrifugal force of 8000g-17000g for 30-60 minutes for gradient centrifugation. Finally, the juice is centrifuged at a relative centrifugal force of 100000g-150000g for 60-100 minutes to enrich the fresh tea leaf nanoparticles.

[0013] Preferably, the fresh tea leaves are fresh tea leaves from spring or autumn, and the nanoparticles from the fresh tea leaves have a lipid membrane structure with a tea saucer-like shape and a particle size of 100-300 nm.

[0014] Preferably, in step S2, the concentration of the carboxymethyl chitosan solution is 4-6%.

[0015] Preferably, in step S3, the concentration of fresh tea leaf nanoparticles is 1-10 mg / mL.

[0016] Preferably, in step S3, the volume ratio of fresh tea leaf nanoparticles to carboxymethyl chitosan solution is 1:10 to 1:50, the mixing time is 3-10 min, and the mixing speed is 100-600 rpm.

[0017] Preferably, in step S4, the concentration of the oxidized hyaluronic acid solution is 3-5%.

[0018] Preferably, in step S5, the volume ratio of the carboxymethyl chitosan solution of fresh tea nanoparticles to the oxidized hyaluronic acid solution is 1-6:1-6, and the gelation time is 10-20 min.

[0019] The hydrogel dressing containing fresh tea leaf nanoparticles was prepared by the method described above.

[0020] The present invention also provides the application of hydrogel dressings containing fresh tea leaf nanoparticles for the preparation of drugs for treating infected wounds.

[0021] The advantages and beneficial effects of the hydrogel dressing containing fresh tea leaf nanoparticles, its preparation method, and its application in this invention are as follows:

[0022] 1. This invention uses carboxymethyl chitosan and oxidized hyaluronic acid to rapidly crosslink into a gel at room temperature. The preparation process is simple and easy to control, and its adhesiveness can be improved by optimizing the ratio. Fresh tea leaf nanoparticles are loaded into this hydrogel. Since fresh tea leaf nanoparticles are obtained from natural plant sources through centrifugation extraction, they can be prepared in large quantities and have good antibacterial properties, without being limited by problems such as increased antibiotic resistance and frequent dressing changes.

[0023] 2. This invention applies a hydrogel dressing containing fresh tea leaf nanoparticles to the treatment of infected wounds. The hydrogel dressing can act slowly and continuously on the infected wound to eliminate harmful bacteria, effectively resist multidrug-resistant bacterial infections, and at the same time promote wound healing and skin regeneration.

[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating the preparation process of the fresh tea leaf nanoparticles of this invention.

[0026] Figure 2 This is a graph showing the particle count detection results of the nanoparticles in fresh tea leaves according to the present invention.

[0027] Figure 3 This is a graph showing the particle size detection results of the fresh tea nanoparticles of this invention.

[0028] Figure 4 This is a graph showing the potential detection results of the fresh tea nanoparticles of the present invention.

[0029] Figure 5 This is a transmission electron microscope image of the nanoparticles from fresh tea leaves according to the present invention.

[0030] Figure 6 This is a diagram showing the results of the present invention's method of inhibiting the growth of Staphylococcus aureus using fresh tea nanoparticles;

[0031] Figure 7 This is a statistical chart showing the number of Staphylococcus aureus colonies inhibited by the nanoparticles derived from fresh tea leaves in this invention.

[0032] Figure 8This image shows the determination of the ratio of carboxymethyl chitosan solution to oxidized hyaluronic acid solution and the gelation time in the preparation of the hydrogel dressing containing fresh tea leaf nanoparticles of the present invention.

[0033] Figure 9 This is an image showing the adhesion evaluation of the hydrogel dressing containing fresh tea leaf nanoparticles of the present invention.

[0034] Figure 10 This is a flowchart illustrating the preparation process of the hydrogel dressing containing fresh tea leaf nanoparticles according to the present invention.

[0035] Figure 11 This is a schematic diagram of the hydrogel dressing containing fresh tea leaf nanoparticles of the present invention for use in infected wounds.

[0036] Figure 12 A diagram illustrating how hydrogel dressings containing fresh tea leaf nanoparticles promote the healing of infected wounds. Detailed Implementation

[0037] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0039] Unless otherwise defined, all reagents, materials and equipment used in this invention are commercially available.

[0040] A method for preparing a hydrogel dressing containing nanoparticles derived from fresh tea leaves includes the following steps:

[0041] S1. Preparation of Fresh Tea Leaf Nanoparticles: The preparation process of fresh tea leaf nanoparticles is as follows: Fresh tea leaves and phosphate buffer are poured into a juicer and juiced at a power of 200-1000W for at least 2 minutes to completely break down the tea leaves. The juice is then squeezed through a 100-200 mesh filter to obtain fresh tea leaf juice. This juice is then subjected to gradient centrifugation at a relative centrifugal force of 300g-1800g for 5-15 minutes, 2000g-6000g for 15-35 minutes, and 8000g-17000g for 30-60 minutes. Finally, it is centrifuged at a relative centrifugal force of 100000g-150000g for 60-100 minutes to enrich the fresh tea leaf nanoparticles. The fresh tea leaves are from spring or autumn. The fresh tea leaf nanoparticles have a saucer-like lipid membrane structure with a particle size of 100-300 nm.

[0042] S2. Dissolve carboxymethyl chitosan to obtain a carboxymethyl chitosan solution with a concentration of 4-6%.

[0043] S3. Mix the obtained carboxymethyl chitosan solution with fresh tea leaf nanoparticles to prepare a carboxymethyl chitosan solution containing fresh tea leaf nanoparticles. The concentration of the fresh tea leaf nanoparticles is 1-10 mg / mL. The volume ratio of the fresh tea leaf nanoparticles to the carboxymethyl chitosan solution is 1:10 to 1:50, the mixing time is 3-10 min, and the mixing speed is 100-600 rpm.

[0044] S4. Dissolve the oxidized hyaluronic acid to obtain an oxidized hyaluronic acid solution with a concentration of 3-5%.

[0045] S5. The obtained carboxymethyl chitosan solution containing fresh tea leaf nanoparticles is mixed with an oxidized hyaluronic acid solution to obtain a hydrogel dressing loaded with fresh tea leaf nanoparticles. The volume ratio of the carboxymethyl chitosan solution containing fresh tea leaf nanoparticles to the oxidized hyaluronic acid solution is 1-6:1-6, and the gelation time is 10-20 min.

[0046] The application of hydrogel dressings containing nanoparticles derived from fresh tea leaves in the preparation of drugs for treating infected wounds.

[0047] Example 1

[0048] Preparation methods of fresh tea leaf nanoparticles, such as... Figure 1 As shown, the steps are as follows:

[0049] Fresh tea leaves and phosphate buffer were added to a juicer at a 1:1 ratio and juiced for 2 minutes. The juice was then extracted using a filter to obtain the stock solution. The two stock solutions were centrifuged using a gradient program: 1000g for 10 minutes, 2000g for 20 minutes, and 10000g for 40 minutes. After gradient centrifugation, the supernatant was transferred to an ultrafiltration tube, balanced, and centrifuged at 150000g for 70 minutes. After centrifugation, a certain amount of phosphate buffer was added to resuspend the precipitate. The precipitate was then filtered through a 0.22μm filter to obtain fresh tea leaf nanoparticles, which were collected for subsequent concentration determination. The nanoparticles were then stored at -80℃ for later use.

[0050] Example 2

[0051] Characterization of nanoparticles derived from fresh tea leaves:

[0052] (1) Determination of particle number by nanotracker

[0053] Clean the sample pool with deionized water;

[0054] The instrument was calibrated using polystyrene microspheres (particle size: 100nm, part number: 3100A, brand: ThermoFisher).

[0055] The sample pool was cleaned with phosphate buffer.

[0056] The sample was diluted with phosphate buffer and then injected for testing. The test results are as follows: Figure 2 As shown, the number of nanoparticles from fresh tea leaves is 6.4 × 10⁻⁶. 11 indivual.

[0057] (2) Determine its particle size and potential.

[0058] Take 20 μL of sample, dilute it to 2 ml, and measure the particle size and potential using a Bruker nanoparticle size analyzer.

[0059] like Figure 3 As shown, the particle size of the fresh tea nanoparticles prepared in Example 1 was measured to be 190 nm using a nanoparticle size analyzer.

[0060] like Figure 4 As shown, the potential of the nanoparticles from fresh tea leaves is -22mV.

[0061] (3) Transmission electron microscopy characterization

[0062] Take 30 μL of the well-mixed sample and drop it onto a copper grid with a carbon support film. Let it stand for 5 minutes, then use filter paper to absorb any remaining liquid from the edge of the grid. Add 2% phosphotungstic acid to the copper grid and stain for 30 seconds at room temperature. Absorb any excess stain with filter paper and allow it to air dry. Observe under a JEM-1400FLASH transmission electron microscope.

[0063] like Figure 5 As shown, the morphology of nanoparticles from fresh tea leaves was detected by transmission electron microscopy. Under the transmission electron microscope, they appear as disc-shaped or saucer-shaped particles with a particle size of about 200 nm.

[0064] Example 3

[0065] The evaluation of the inhibition of Staphylococcus aureus by nanoparticles derived from fresh tea leaves was conducted as follows:

[0066] (1) Measure the optical density (OD) value of the shaken third-generation Staphylococcus aureus and dilute it to the range of 0.6-0.8;

[0067] (2) Take a quantitative bacterial suspension with an OD value in the range of 0.6-0.8 and dilute it 1:1000 with LB liquid medium to a colony count of 1×10⁻⁶. 6 CFU / mL;

[0068] (3) Pour 15 ml of LB liquid culture medium into the petri dish;

[0069] (4) Take 50 μL of bacterial solution to prepare 1×10⁻⁶ bacterial culture solution. 6 Mix CFU / mL with 100μL of fresh tea leaf nanoparticles:

[0070] (5) Incubate at 37℃, 200rpm for 2.5 hours;

[0071] (6) Take 100 μL of sample into a petri dish and spread it evenly with a spreading stick;

[0072] (7) Incubate the petri dish at 37°C overnight, and then take a picture.

[0073] like Figure 6 As shown, nanoparticles derived from fresh tea leaves have a significant inhibitory effect on the growth of Staphylococcus aureus.

[0074] Colony count is one of the indicators of bacterial growth and reproduction; the higher the colony count, the faster the bacteria grow. For example... Figure 7 As shown, the bacterial colony count in the normal control group was 10. 5 The values ​​around 100 indicate that the nanoparticles do not inhibit bacterial growth, while the colony count of the fresh tea-derived nanoparticles is 0. This evidence suggests that the fresh tea-derived nanoparticles have a significant inhibitory effect on the growth of Staphylococcus aureus, while the normal control group showed no inhibitory effect.

[0075] Example 4

[0076] Preparation of carboxymethyl chitosan and oxidized hyaluronic acid hydrogel dressing:

[0077] Weigh out two portions of oxidized hyaluronic acid, 3g and 4g respectively, and dissolve them in 10mL of deionized water to obtain oxidized hyaluronic acid solutions with mass fractions of 3% and 4%.

[0078] Weigh out three portions of carboxymethyl chitosan powder, with masses of 4g, 5g, and 6g respectively, and dissolve them in 10mL of deionized water to obtain carboxymethyl chitosan solutions with mass fractions of 4%, 5%, and 6%.

[0079] Mix a 4% carboxymethyl chitosan solution with 3% and 4% oxidized hyaluronic acid solutions at room temperature and record the gelation time; mix a 5% carboxymethyl chitosan solution with 3% and 4% oxidized hyaluronic acid solutions at room temperature and record the gelation time; mix a 5% carboxymethyl chitosan solution with 3% and 4% oxidized hyaluronic acid solutions at room temperature and record the gelation time.

[0080] like Figure 8 As shown, the carboxymethyl chitosan-oxidized hyaluronic acid hydrogels with ratios of 4%+3% and 5%+3% exhibit high fluidity within 30 minutes; the carboxymethyl chitosan-oxidized hyaluronic acid hydrogels with ratios of 4%+3%, 5%+4%, and 5%+3% form within 3 minutes, but have poor adhesiveness. The carboxymethyl chitosan-oxidized hyaluronic acid hydrogel with a ratio of 6%+3% forms within 10 minutes and exhibits good adhesion.

[0081] Drop the hydrogel of the experimentally determined proportions onto your hand and rotate it horizontally at 90°, horizontally rotated at 90°, and horizontally rotated at 180°. Observe the adhesive properties of the hydrogel.

[0082] like Figure 9 As shown, the 6%+3% carboxymethyl chitosan-oxidized hyaluronic acid hydrogel exhibits good adhesion to the skin and did not detach at different levels.

[0083] The optimal ratio was determined based on gelation time and adhesion properties. A 6% + 3% carboxymethyl chitosan-oxidized hyaluronic acid hydrogel was used for the subsequent preparation of hydrogel dressings loaded with fresh tea leaf nanoparticles.

[0084] Example 5

[0085] A method for preparing hydrogel dressings containing fresh tea leaf nanoparticles, such as... Figure 10 As shown, it includes the following steps:

[0086] 1. Weigh 6g of carboxymethyl chitosan powder and dissolve it in 10mL of deionized water to obtain a 6% carboxymethyl chitosan solution.

[0087] 2. Weigh 3g of oxidized transparent powder and dissolve it in 10mL of deionized water to obtain a 3% oxidized hyaluronic acid solution.

[0088] 3. The obtained 6% carboxymethyl chitosan solution was mixed with fresh tea leaf nanoparticles to prepare a carboxymethyl chitosan solution containing fresh tea leaf nanoparticles, wherein the concentration of fresh tea leaf nanoparticles was 10 mg / ml and the volume ratio of fresh tea leaf nanoparticles to carboxymethyl chitosan solution was 1:40.

[0089] 4. Finally, the carboxymethyl chitosan solution containing fresh tea nanoparticles is mixed with the oxidized hyaluronic acid solution to obtain a hydrogel dressing containing fresh tea nanoparticles. The volume ratio of the carboxymethyl chitosan solution containing fresh tea nanoparticles to the oxidized hyaluronic acid solution is 1:1.

[0090] Example 6

[0091] Hydrogel dressings containing nanoparticles derived from fresh tea leaves are applied to infected wounds to promote wound healing.

[0092] The steps to establish an animal model of infected wounds are as follows:

[0093] (1) Six-week-old male SD rats were housed at the Experimental Animal Center of the Institute of Medical Sciences, Northwestern Polytechnical University. After one week of free-range feeding, all rats were shaved and 10 mm wide wounds were made on their bodies using a skin circumcision device. Wounds without bacterial infection served as the blank control group.

[0094] (2) Apply 50 μL of Staphylococcus aureus suspension (1×10⁻⁶) to the wound. 8 The bacterial count (CFU / mL) was inoculated into the wounds of each rat and allowed to be absorbed for 10 minutes to form an infected wound. Infected wounds without hydrogel dressing were classified as the bacterial infection group.

[0095] (3) Subsequently, carboxymethyl chitosan cross-linked oxidized hyaluronic acid blank hydrogel was applied to the infected wound, and the wound was divided into two groups: the blank hydrogel group and the fresh tea leaf nanoparticle hydrogel dressing was applied directly to the wound, and the fresh tea leaf nanoparticle hydrogel group was also divided into two groups. The dressing was changed every 2 days for the first 6 days, and wound photos were taken on the 2nd, 4th and 8th days.

[0096] like Figure 11 As shown, Figure 11 A schematic diagram illustrating the use of a hydrogel dressing containing nanoparticles derived from fresh tea leaves for infected wounds.

[0097] like Figure 12 As shown, Figure 12 Photograph of a hydrogel dressing containing nanoparticles derived from fresh tea leaves applied to an infected wound. Infected wounds are prone to bacterial infection, resulting in slow healing and the formation of infectious material at the wound site, severely hindering wound healing. Without intervention, wound infection leads to slow healing. The healing progress of an infected wound is measured by the area of ​​healing; better healing results in a smaller wound area, and vice versa. As shown in the figure, the wounds in the bacterial infection group healed more slowly than those in the normal control group. The wound area in the group treated with fresh tea-derived nanoparticle hydrogel was smaller than that in other groups, indicating that it had a certain promoting effect on wound healing and greatly improved the infection of the wound. The wound area of ​​the blank hydrogel treated with only carboxymethyl chitosan and oxidized hyaluronic acid was similar to that of the bacterial infection group. The results indicate that the blank hydrogel treated with only carboxymethyl chitosan and oxidized hyaluronic acid cannot promote wound healing. Only the combination of fresh tea-derived nanoparticles and hydrogel can achieve the goal of rapid healing of infected wounds in a short time. This provides an excellent strategy for the healing of infected wounds. The combination of the two can continuously act on infected wounds to promote wound healing, eliminate harmful bacteria, effectively resist multidrug-resistant bacterial infections, and simultaneously promote the healing of infected wounds and skin regeneration.

[0098] Therefore, the present invention employs the above-mentioned hydrogel dressing containing fresh tea leaf nanoparticles, its preparation method, and its application. Carboxymethyl chitosan and oxidized hyaluronic acid are rapidly cross-linked into a gel at room temperature. The preparation process is simple and easy to control. The fresh tea leaf nanoparticles loaded in the hydrogel are not limited by problems such as increased antibiotic resistance and frequent dressing changes. It can slowly and continuously act on infected wounds to promote wound healing, eliminate harmful bacteria, effectively resist multidrug-resistant bacterial infections, and simultaneously promote the healing of infected wounds and skin regeneration.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A hydrogel dressing containing nanoparticles derived from fresh tea leaves, characterized in that, Prepared by a method including the following steps: S1. Preparation of fresh tea leaf nanoparticles: The preparation process of fresh tea leaf nanoparticles is as follows: Fresh tea leaves and phosphate buffer are mixed and juiced. The juicing power is 200-1000w and the juicing time is at least 2min to completely break the tea leaves. The juice is squeezed through a 100-200 mesh filter to obtain fresh tea leaf juice. Then, the juice is centrifuged at a relative centrifugal force of 300g-1800g for 5-15min, at a relative centrifugal force of 2000g-6000g for 15-35min, and at a relative centrifugal force of 8000g-17000g for 30-60min for gradient centrifugation. Finally, the juice is centrifuged at a relative centrifugal force of 100000g-150000g for 60-100min to enrich fresh tea leaf nanoparticles. S2. Dissolve carboxymethyl chitosan to obtain a carboxymethyl chitosan solution; S3. Mix the obtained carboxymethyl chitosan solution with fresh tea leaf nanoparticles to prepare a carboxymethyl chitosan solution containing fresh tea leaf nanoparticles. S4. Dissolve the oxidized hyaluronic acid to obtain an oxidized hyaluronic acid solution; S5. Mix the obtained carboxymethyl chitosan solution containing fresh tea nanoparticles with oxidized hyaluronic acid solution to form a gel, and obtain a hydrogel dressing containing fresh tea nanoparticles. Fresh tea leaves are those harvested in spring or autumn. The nanoparticles derived from fresh tea leaves have a lipid membrane structure resembling a tea saucer, with a particle size of 100-300 nm.

2. The hydrogel dressing containing fresh tea leaf nanoparticles according to claim 1, characterized in that: In step S2, the concentration of the carboxymethyl chitosan solution is 4-6%.

3. The hydrogel dressing containing fresh tea leaf nanoparticles according to claim 1, characterized in that: In step S3, the concentration of fresh tea leaf nanoparticles is 1-10 mg / mL.

4. The hydrogel dressing containing fresh tea leaf nanoparticles according to claim 1, characterized in that: In step S3, the volume ratio of fresh tea leaf nanoparticles to carboxymethyl chitosan solution is 1:10 to 1:50, the mixing time is 3-10 min, and the mixing speed is 100-600 rpm.

5. The hydrogel dressing containing fresh tea leaf nanoparticles according to claim 1, characterized in that: In step S4, the concentration of the oxidized hyaluronic acid solution is 3-5%.

6. The hydrogel dressing containing fresh tea leaf nanoparticles according to claim 1, characterized in that: In step S5, the volume ratio of the carboxymethyl chitosan solution of fresh tea nanoparticles to the oxidized hyaluronic acid solution is 1-6:1-6, and the gelation time is 10-20 min.

7. The use of the hydrogel dressing containing fresh tea leaf nanoparticles as described in any one of claims 1-6 in the preparation of a medicament for treating infected wounds.

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