Hydrogel dressing loaded with fresh tea leaf source nano-particles as well as preparation method and application of hydrogel dressing

Abstract

The invention belongs to the technical field of hydrogel dressings, and particularly discloses a hydrogel dressing carrying fresh tea leaf source nano-particles and a preparation method and application of the hydrogel dressing carrying the fresh tea leaf source nano-particles, and the preparation method comprises the following steps: preparing the fresh tea leaf source nano-particles; preparing a carboxymethyl chitosan solution; preparing a carboxymethyl chitosan solution containing the fresh tea leaf source nanoparticles; preparing an oxidized hyaluronic acid solution; and mixing the obtained carboxymethyl chitosan solution containing the fresh tea leaf source nano-particles with an oxidized hyaluronic acid solution to obtain the hydrogel dressing carrying the fresh tea leaf source nano-particles. According to the hydrogel dressing loaded with the fresh tea source nano-particles, the preparation method and the application, the preparation process is simple and easy to control and is not limited by the problems of antibiotic drug resistance increase, frequent dressing replacement and the like, wound healing is promoted, harmful bacteria are removed, and the wound healing effect is good. Multiple drug-resistant bacterial infection can be effectively resisted, and infected wound healing and skin regeneration can be promoted at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogel dressings, in particular to a hydrogel dressing carrying fresh tea-source nanoparticles, and a preparation method and application thereof. Background Art

[0002] Bacterial infection is the most common problem encountered during wound healing and skin regeneration. The severe inflammatory response caused by infection not only significantly increases infection-related complications, but also significantly reduces the quality of wound healing. In addition, the treatment of bacterially infected wounds is difficult, the course of treatment is long, and the cost is high, which will cause a huge economic burden on patients and society. At present, antibiotics are mainly used to treat infected wounds in clinical practice. However, due to drug resistance and the lack of a suitable skin repair microenvironment, the treatment effects of anti-infection and wound healing are not ideal. Therefore, how to effectively resist multidrug-resistant bacterial infections and promote infected wound healing and skin regeneration at the same time is still a major problem that needs to be solved urgently.

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

[0004] Current methods for treating infected wounds include conventional debridement, oral antibiotics, antimicrobial dressings, negative pressure wound therapy, etc., but these methods are limited by the increase in antibiotic resistance and frequent dressing changes. Therefore, an innovative treatment strategy that is minimally invasive, can promote drug penetration and achieve long-term effectiveness is needed. Therefore, it is necessary to develop an efficient anti-infective wound dressing. Summary of the invention

[0005] The purpose of the present invention is to provide a hydrogel dressing loaded with tea-derived nanoparticles, a preparation method and an application thereof. Carboxymethyl chitosan and oxidized hyaluronic acid are used to rapidly cross-link into a gel at room temperature. The preparation process is simple and easy to control. Fresh tea-derived nanoparticles are loaded in the hydrogel, which is not restricted by problems such as increased antibiotic resistance and frequent dressing changes. The hydrogel can slowly and continuously act on infected wounds, thereby achieving the effects of removing harmful bacteria, effectively resisting multi-drug resistant bacterial infections and promoting the healing of infected wounds and skin regeneration.

[0006] To achieve the above object, the present invention provides a method for preparing a hydrogel dressing containing fresh tea-derived nanoparticles, comprising the following steps:

[0007] S1. preparing fresh tea-derived nanoparticles;

[0008] S2, dissolving carboxymethyl chitosan to obtain a carboxymethyl chitosan solution;

[0009] S3, mixing the obtained carboxymethyl chitosan solution with fresh tea-derived nanoparticles to prepare a carboxymethyl chitosan solution containing fresh tea-derived nanoparticles;

[0010] S4, dissolving the oxidized hyaluronic acid to obtain an oxidized hyaluronic acid solution;

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

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

[0013] Preferably, the fresh tea leaves are fresh tea leaves from spring or autumn, and the nanoparticles derived from fresh tea leaves are tray-shaped lipid membrane structures with 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 the fresh tea-derived nanoparticles is 1-10 mg / mL.

[0016] Preferably, in step S3, the volume ratio of fresh tea-derived nanoparticles to carboxymethyl chitosan solution is 1:10-1:50, 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-derived nanoparticles to the oxidized hyaluronic acid solution is 1-6:1-6, and the gelling time is 10-20 min.

[0019] The hydrogel dressing loaded with fresh tea-leaf-derived nanoparticles is prepared by the above-mentioned preparation method.

[0020] The present invention also provides the use of a hydrogel dressing loaded with fresh tea-leaf-derived nanoparticles, which is used for preparing a medicine for treating infected wounds.

[0021] The advantages and beneficial effects of the hydrogel dressing containing fresh tea-derived nanoparticles, the preparation method and the application of the present invention are:

[0022] 1. The present invention uses carboxymethyl chitosan and oxidized hyaluronic acid to crosslink into gel at room temperature quickly. The preparation process is simple and easy to control, and its adhesion is improved by optimizing the ratio. Fresh tea-derived nanoparticles are loaded in the hydrogel. Since fresh tea-derived nanoparticles are obtained from natural plants through centrifugal extraction and can be prepared in large quantities, they have good antibacterial properties and are not limited by problems such as increased antibiotic resistance and frequent dressing changes.

[0023] 2. The present invention applies hydrogel dressings loaded with fresh tea-derived nanoparticles to the treatment of infected wounds. The hydrogel dressings can act slowly and continuously on the infected wounds to remove harmful bacteria, effectively resist multidrug-resistant bacterial infections, and simultaneously promote the healing of infected wounds and skin regeneration.

[0024] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of the preparation of fresh tea-derived nanoparticles of the present invention;

[0026] Figure 2 This is a graph showing the particle number detection result of the fresh tea nanoparticles of the present invention;

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

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

[0029] Figure 5 This is a transmission electron microscope image of fresh tea nanoparticles of the present invention;

[0030] Figure 6 This is a graph showing the results of the fresh tea nanoparticles of the present invention inhibiting the growth of Staphylococcus aureus;

[0031] Figure 7 This is a statistical graph showing the colony count of Staphylococcus aureus inhibited by the fresh tea-derived nanoparticles of the present invention;

[0032] Figure 8It is a diagram showing the determination of the ratio of the carboxymethyl chitosan solution to the oxidized hyaluronic acid solution and the gelation time in the preparation of the hydrogel dressing containing fresh tea-derived nanoparticles of the present invention;

[0033] Fig. 9 This is a graph evaluating the adhesion of the hydrogel dressing loaded with fresh tea-derived nanoparticles of the present invention;

[0034] Fig.10 This is a flow chart for preparing the hydrogel dressing containing fresh tea-derived nanoparticles of the present invention;

[0035] Fig.11 This is a schematic diagram of the hydrogel dressing loaded with fresh tea-derived nanoparticles of the present invention being used for infected wounds;

[0036] Fig.12 Hydrogel dressing loaded with fresh tea-derived nanoparticles promotes healing of infected wounds. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0038] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

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

[0040] The preparation method of the hydrogel dressing containing fresh tea-derived nanoparticles comprises the following steps:

[0041] S1. Prepare fresh tea-derived nanoparticles. The preparation process of fresh tea-derived nanoparticles is as follows: pour fresh tea leaves and phosphate buffer into a juicer to squeeze juice, the juice squeezing power is 200-1000w, the juice squeezing time is at least 2min, the tea leaves are completely broken, and fresh tea juice is squeezed through a 100-200 mesh filter to obtain fresh tea juice, and then centrifuged at a relative centrifugal force of 300g-1800g for 5-15min, at a relative centrifugal force of 2000g-6000g for 15-35min, at a relative centrifugal force of 8000g-17000g for 30-60min for gradient centrifugation, and then at a relative centrifugal force of 100000g-150000g for 60-100min to enrich fresh tea-derived nanoparticles. Fresh tea leaves are fresh tea leaves in spring or autumn, and fresh tea-derived nanoparticles are tray-shaped lipid membrane structures with a particle size of 100-300nm.

[0042] S2. Dissolving carboxymethyl chitosan to obtain a carboxymethyl chitosan solution, wherein the concentration of the carboxymethyl chitosan solution is 4-6%.

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

[0044] S4. Dissolving the oxidized hyaluronic acid to obtain an oxidized hyaluronic acid solution, wherein the concentration of the oxidized hyaluronic acid solution is 3-5%.

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

[0046] Application of hydrogel dressing loaded with fresh tea-leaf derived nanoparticles for the preparation of medicaments for the treatment of infected wounds.

[0047] Example 1

[0048] The preparation method of fresh tea-derived nanoparticles, such as Figure 1 As shown, the steps are as follows:

[0049] Fresh tea leaves and phosphate buffer were poured into a juicer at a ratio of 1:1. After 2 minutes of juicing, the original solution was squeezed with a filter. The two original solutions were centrifuged at 1000g for 10 minutes, 2000g for 20 minutes, and 10000g for 40 minutes. After the gradient centrifugation, the supernatant was poured into an ultracentrifuge tube for balance, and centrifuged at 150000g for 70 minutes. After the centrifugation, a certain amount of phosphate buffer was added to resuspend the precipitate, and then filtered with a 0.22μm filter membrane to obtain fresh tea-derived nanoparticles, which were collected for subsequent concentration determination. Then placed in a -80℃ refrigerator for standby use.

[0050] Example 2

[0051] Characterization of fresh tea-derived nanoparticles:

[0052] (1) Determination of the number of nanotracker particles

[0053] Rinse the sample pool with deionized water;

[0054] The instrument was calibrated with polystyrene microspheres (particle size: 100 nm, product number: 3100A, brand: ThermoFisher);

[0055] Wash the sample pool with phosphate buffered saline;

[0056] The sample was diluted with phosphate buffer and injected for testing. Figure 2 As shown, the particle number of fresh tea-derived nanoparticles is 6.4×10 11 indivual.

[0057] (2) Determination of particle size and potential

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

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

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

[0061] (3) Transmission electron microscopy characterization

[0062] Take 30uL of the mixed sample and drop it on the carbon support film copper mesh, let it stand for 5 minutes, and use filter paper to absorb the residual liquid from the edge of the copper mesh. Add 2% phosphotungstic acid to the copper mesh, dye it at room temperature for 30 seconds, use filter paper to absorb the excess dye, and dry it naturally. Observe under JEM-1400FLASH transmission electron microscope.

[0063] like Figure 5 As shown, the transmission electron microscopy morphology of fresh tea-derived nanoparticles was detected, which appeared to be disc-shaped or tray-shaped under a transmission electron microscope, with a particle size of about 200 nm.

[0064] Example 3

[0065] The evaluation of fresh tea-derived nanoparticles against Staphylococcus aureus was performed as follows:

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

[0067] (2) Take the bacterial solution with a quantitative OD value in the range of 0.6-0.8 and dilute it with LB liquid medium at a ratio of 1:1000 until the colony count is 1×10 6 CFU / mL;

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

[0069] (4) Take 50 μL of bacterial solution to make a 1×10 6 CFU / mL mixed with 100μL of fresh tea-derived nanoparticles:

[0070] (5) Incubate at 37°C, 200 rpm, for 2.5 h;

[0071] (6) Take 100 μL of the sample and spread it evenly in a culture dish using a coating stick;

[0072] (7) The culture dish was incubated at 37°C overnight and then photographed.

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

[0074] The number of colonies is one of the indicators of bacterial growth and reproduction. The more colonies there are, the faster the bacteria grow. Figure 7 As shown, the number of bacterial colonies in the normal control group was 10 5 The number of colonies of fresh tea-derived nanoparticles was about 0, indicating that the bacterial growth was not inhibited, while the colony count of fresh tea-derived nanoparticles was 0. The above evidence shows that fresh tea-derived nanoparticles have a significant inhibitory effect on the growth of Staphylococcus aureus, while the normal control group has no inhibitory effect.

[0075] Example 4

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

[0077] Weigh two portions of oxidized hyaluronic acid, with masses of 3 g and 4 g respectively, and add them into 10 mL of deionized water to dissolve, thereby obtaining oxidized hyaluronic acid solutions with mass fractions of 3% and 4%;

[0078] Weigh three portions of carboxymethyl chitosan powder, with masses of 4 g, 5 g, and 6 g respectively, and add them into 10 mL of deionized water to dissolve, thereby obtaining carboxymethyl chitosan solutions with mass fractions of 4%, 5%, and 6%;

[0079] A 4% carboxymethyl chitosan solution was mixed with a 3% and 4% oxidized hyaluronic acid solution by mass at room temperature, and the gelation time was recorded; a 5% carboxymethyl chitosan solution was mixed with a 3% and 4% oxidized hyaluronic acid solution by mass at room temperature, and the gelation time was recorded; a 5% carboxymethyl chitosan solution was mixed with a 3% and 4% oxidized hyaluronic acid solution by mass at room temperature, and the gelation time was recorded.

[0080] like Figure 8 As shown in the figure, the carboxymethyl chitosan-oxidized hyaluronic acid hydrogels with a ratio of 4% + 3% and 5% + 3% have high fluidity within 30 minutes; the carboxymethyl chitosan-oxidized hyaluronic acid hydrogels with a ratio of 4% + 3%, 5% + 4% and 5% + 3% have a gelation time of 10 minutes, but poor viscosity. The carboxymethyl chitosan-oxidized hyaluronic acid hydrogel with a ratio of 6% + 3% has a gelation time of 10 minutes, and has good viscosity.

[0081] Drop the hydrogel with the above-explored ratio on your hand, and observe the adhesion performance of the hydrogel at 90° horizontally, 90° horizontally flipped, and 180° horizontally.

[0082] like Fig. 9 As shown, the 6%+3% carboxymethyl chitosan-oxidized hyaluronic acid hydrogel has good adhesion on the skin and does not fall off at different levels.

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

[0084] Example 5

[0085] A method for preparing a hydrogel dressing loaded with fresh tea-derived nanoparticles, such as Fig.10 As shown, the following steps are included:

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

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

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

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

[0090] Example 6

[0091] Hydrogel dressings loaded with fresh tea-derived nanoparticles were applied to infected wounds to promote wound healing.

[0092] To establish an animal model of infected wounds, the steps are as follows:

[0093] (1) Six-week-old male SD rats were raised in the Experimental Animal Center of the Medical Research Institute of Northwestern Polytechnical University. After one week of free diet adaptation, all rats were depilated and wounds with a width of 10 mm were cut on the rats with a skin ring cutter. The wounds without bacterial infection served as the blank control group.

[0094] (2) Apply 50 μL of Staphylococcus aureus suspension (1×10 8 The hydrogel was inoculated into the wound surface of each rat and allowed to absorb for 10 min to form infected wounds. The infected wounds without hydrogel dressings were designated 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 group was divided into a blank hydrogel group, and a fresh tea-derived nanoparticle hydrogel dressing was directly applied to the wound surface, and the group was divided into a fresh tea-derived nanoparticle hydrogel group. The dressing was renewed every 2 days for the first 6 days, and wound photos were taken on the 2nd, 4th, and 8th days.

[0096] like Fig.11 As shown, Fig.11 Schematic diagram of hydrogel dressing loaded with fresh tea-derived nanoparticles for use in infected wounds.

[0097] like Fig.12 As shown, Fig.12 This is a photo of a hydrogel dressing loaded with fresh tea-derived nanoparticles used on an infected wound. Infected wounds can be infected with bacteria, which can heal slowly and form infections at the wound site, seriously affecting wound healing. If no intervention is given, wound infection can cause slow wound healing. The healing of infected wounds can be measured by the wound healing area. The better the healing, the smaller the wound area. Conversely, the worse the healing, the larger the wound area. It can be seen from the figure that the wounds in the bacterial infection group healed slowly compared with the normal control group. The wound area of ​​the group given fresh tea source nanoparticle hydrogel was smaller than that of other groups, indicating that it has a certain promoting effect on wound healing and greatly improves the infection of the wound. The wound healing area of ​​the blank hydrogel given only carboxymethyl chitosan and oxidized hyaluronic acid was similar to that of the bacterial infection group. The results showed that the blank hydrogel of simple carboxymethyl chitosan and oxidized hyaluronic acid could not promote wound healing. Only the combination of fresh tea source nanoparticles and hydrogel can achieve the purpose of infectious wound healing at a high speed in a short time, providing an excellent strategy for infectious wound healing. The combination of the two can continuously act on infected wounds to promote wound healing, eliminate harmful bacteria, effectively resist multidrug-resistant bacterial infection, and at the same time promote the healing of infected wounds and skin regeneration.

[0098] Therefore, the present invention adopts the above-mentioned hydrogel dressing loaded with fresh tea-leaf source nanoparticles, preparation method and application, uses carboxymethyl chitosan and oxidized hyaluronic acid to quickly cross-link into gel at room temperature, the preparation process is simple and easy to control, fresh tea-leaf source nanoparticles are loaded in the hydrogel, will not be restricted by problems such as increased antibiotic resistance and frequent dressing changes, and can slowly and continuously act on infected wounds, thereby promoting wound healing, removing harmful bacteria, effectively resisting multi-drug resistant bacterial infection and promoting infected wound healing and skin regeneration at the same time.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a hydrogel dressing containing fresh tea-derived nanoparticles, characterized in that: The steps include: S1. preparing fresh tea-derived nanoparticles; S2, dissolving carboxymethyl chitosan to obtain a carboxymethyl chitosan solution; S3, mixing the obtained carboxymethyl chitosan solution with fresh tea-derived nanoparticles to prepare a carboxymethyl chitosan solution containing fresh tea-derived nanoparticles; S4, dissolving the oxidized hyaluronic acid to obtain an oxidized hyaluronic acid solution; S5. Mix the obtained carboxymethyl chitosan solution containing fresh tea-leaf-derived nanoparticles with the oxidized hyaluronic acid solution to form a gel, thereby obtaining a hydrogel dressing loaded with fresh tea-leaf-derived nanoparticles.

2. The method for preparing the hydrogel dressing containing fresh tea-derived nanoparticles according to claim 1, characterized in that: In step S1, the preparation process of fresh tea source nanoparticles is as follows: fresh tea leaves and phosphate buffer are mixed and juiced at a juice extraction power of 200 to 1000 W for at least 2 min to completely crush the tea leaves, and fresh tea juice is obtained by squeezing through a 100 to 200 mesh filter, and then centrifuged at a relative centrifugal force of 300 g to 1800 g for 5 to 15 min, at a relative centrifugal force of 2000 g to 6000 g for 15 to 35 min, at a relative centrifugal force of 8000 g to 17000 g for 30 to 60 min for gradient centrifugation, and then at a relative centrifugal force of 100000 g to 150000 g for 60 to 100 min to enrich fresh tea source nanoparticles.

3. The method for preparing the hydrogel dressing containing fresh tea-derived nanoparticles according to claim 2, characterized in that: The fresh tea leaves are fresh tea leaves from spring or autumn. The nanoparticles derived from fresh tea leaves are tray-shaped lipid membrane structures with a particle size of 100-300 nm.

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

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

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

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

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

9. A hydrogel dressing containing fresh tea-derived nanoparticles, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the hydrogel dressing loaded with fresh tea-derived nanoparticles as claimed in claim 9 in the preparation of a medicament for treating infected wounds.

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