Reductive humic acid polysaccharide hydrogel dressing, preparation method thereof and application of hydrogel dressing in promoting healing of infectious wounds

Abstract

The invention relates to the technical field of biomedical materials, and discloses a reductive humic acid polysaccharide hydrogel dressing, a preparation method thereof and an application of the reductive humic acid polysaccharide hydrogel dressing in promoting healing of infectious wounds. Humic acid is subjected to reductive modification and then subjected to a Schiff base reaction with aldehyde polysaccharide and glycosaminoglycan, and the hydrogel dressing is obtained. Humic acid is modified by sodium borohydride. According to the invention, humic acid is subjected to reductive modification so as to enhance the biological activity of humic acid, meanwhile, a hydrogel skeleton with self-repairing performance is formed through Schiff base reaction between aldehyde polysaccharide and aminated polysaccharide, and reductive humic acid is introduced to construct the multifunctional hydrogel dressing so as to promote the healing of bacterial infectious wounds.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical materials, and in particular to a reducing humic acid polysaccharide hydrogel dressing, a preparation method thereof, and an application thereof in promoting healing of infectious wounds. Background Art

[0002] Skin covers the whole body, protecting various tissues and organs in the body from physical, mechanical, chemical and pathogenic microbial damage, and plays a vital role in maintaining homeostasis. The healing process of skin after being damaged for various reasons includes four overlapping stages: hemostasis, inflammation, proliferation and remodeling, involving cells, body fluids and bioactive factors, with the ultimate goal of restoring the morphology and function of damaged tissues.

[0003] The complex healing process at the wound site is often restricted by various factors such as delayed blood coagulation, reactive oxygen production, chronic inflammation and microbial infection. Among them, the infection caused by the accumulation and growth of bacteria at the wound site is one of the key issues that hinder the recovery of skin wounds and will disrupt the natural repair process. The most commonly used antibiotic therapy for the treatment of bacterial infections may cause bacteria to develop drug resistance, and drug-resistant strains at the wound site may cause serious complications. In addition, rapid wound repair is also crucial, so the preparation of wound dressings that can effectively kill bacteria and effectively accelerate the wound healing process has great application prospects.

[0004] Hydrogels are biomaterials with three-dimensional network structures formed by physical or chemical crosslinking of natural or synthetic polymers. When used as wound dressings, they can protect wounds from invasion by exogenous microorganisms, absorb wound exudate, and provide a favorable environment for wound healing. Ideal hydrogel wound dressings should have strong adhesion and good biosafety, and have multiple functions such as hemostasis, antibacterial, antioxidant, and anti-inflammatory. However, the current hydrogels have insufficient adhesion, and it is difficult to achieve a balance between multiple functions and the effect of regulating wound repair throughout the entire process.

[0005] A large number of studies have shown that hydrogel dressings with natural polysaccharides as the skeleton can effectively promote the healing of damaged tissues in a hydrated environment. In addition, due to its good hydrophilicity and excellent bio-tissue compatibility, it has attracted much attention in the research direction of wound treatment. It is worth noting that polysaccharides are rich in active functional groups such as hydroxyl, amino, and carboxyl groups, which can be chemically modified and cross-linked with other active functional groups, providing the possibility of realizing the multifunctionality of wound dressings. Summary of the invention

[0006] Technical problems solved by the present invention:

[0007] The invention is used to solve the problems of insufficient adhesion and poor wound repair effect of hydrogel dressings in the prior art.

[0008] The technical solution adopted by the present invention is:

[0009] The present invention provides a reducing humic acid polysaccharide hydrogel dressing, which enhances the biological activity of humic acid by reducing modification, forms a hydrogel skeleton with self-repairing properties through the Schiff base reaction between aldehyde-modified polysaccharides and amino-modified polysaccharides, and introduces reducing humic acid to construct a multifunctional hydrogel dressing to promote the healing of bacterially infected wounds.

[0010] The specific contents are as follows:

[0011] First, the present invention provides a reducing humic acid polysaccharide hydrogel dressing. After the humic acid is reductively modified, it is reacted with aldehyde-modified polysaccharide and aminopolysaccharide through Schiff base to obtain the hydrogel dressing; the humic acid is modified with sodium borohydride.

[0012] Humic acid

[0013] According to some preferred embodiments, the mass ratio of humic acid to sodium borohydride is 10:1 to 100:1.

[0014] According to some preferred embodiments, the formaldehyde-modified polysaccharide is a polysaccharide modified by sodium periodate, and the mass ratio of the polysaccharide to the sodium periodate is 10:1 to 100:1.

[0015] According to some preferred embodiments, the polysaccharide in the aldehyde-modified polysaccharide includes at least one of hyaluronic acid, sodium alginate, artemisia annua polysaccharide, and dextran.

[0016] According to some more preferred embodiments, the polysaccharide in the aldehyded polysaccharide is hyaluronic acid.

[0017] According to some preferred embodiments, the amino polysaccharide includes at least one of gelatin, chitosan, and polysaccharide modified by ethylenediamine, and the mass ratio of polysaccharide to ethylenediamine is 10:1 to 100:1.

[0018] According to some preferred embodiments, the polysaccharide in the aminopolysaccharide includes at least one of pectin, hyaluronic acid and sodium alginate.

[0019] According to some more preferred embodiments, the polysaccharide in the amino polysaccharide is pectin.

[0020] Second, the present invention provides a method for preparing the aforementioned reducing humic acid polysaccharide hydrogel dressing, comprising the following steps:

[0021] After the S1 humic acid is purified, sodium borohydride is added to react, and the obtained product is freeze-dried to obtain reduced humic acid;

[0022] The S2 polysaccharide was dissolved in deionized water, an oxidant was added to carry out an aldehyde reaction, and then ethylene glycol was added to terminate the oxidation reaction. The obtained product was purified by dialysis and freeze-dried to obtain the aldehyde polysaccharide;

[0023] S3 polysaccharide was dissolved in N-hydroxybutyric acid imide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide, ethylenediamine was added to carry out an amination reaction, and the obtained product was purified by dialysis and freeze-dried to obtain an aminated polysaccharide;

[0024] S4: Mixing reducing humic acid, aldehyde-modified polysaccharide and amino-modified polysaccharide to obtain a hydrogel dressing.

[0025] Specifically,

[0026] Step 1: Preparation of phenolic hydroxylated humic acid: Sodium humate is dissolved in deionized water, centrifuged to obtain the supernatant, dialyzed, purified, and freeze-dried to obtain purified sodium humate, and then sodium borohydride is added to the purified humic acid, the pH is adjusted to terminate the reaction, and the product is dialyzed and freeze-dried to obtain phenolic hydroxylated humic acid.

[0027] Commercially available sodium humate is generally extracted by alkali dissolution and acid precipitation, and contains a portion of insoluble matter. The soluble components can be obtained by centrifugal purification, and the purity can be improved. The antioxidant and antibacterial activity of humic acid mainly depends on the presence of phenolic hydroxyl groups, so the strong reducing property of sodium borohydride is used to increase its phenolic hydroxyl content.

[0028] Step 2: Preparation of aldehyde-modified polysaccharide: Dissolve the polysaccharide in deionized water and add oxidant NaIO 4 The aldehyde reaction was carried out at room temperature in the dark, and then ethylene glycol was added to terminate the oxidation reaction. The solution after the reaction was dialyzed, purified, and freeze-dried to obtain the aldehyde polysaccharide.

[0029] Step 3: Preparation of amino polysaccharide: After dissolving the polysaccharide, NHS (N-hydroxysuccinimide) and EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide) are added to activate the carboxyl group, and ethylenediamine is added to carry out the amination reaction. Finally, the product is dialyzed, purified, and freeze-dried to obtain purified amino polysaccharide.

[0030] Step 4: Preparation of reducing humic acid polysaccharide hydrogel dressing: Add amino polysaccharide, aldehyde polysaccharide, and reducing humic acid into a centrifuge tube in sequence and vortex mix to form a gel.

[0031] The aldehyde groups in the aldehyde-modified polysaccharide can react with the amino groups in the amino-modified polysaccharide to form a gel through a Schiff base reaction. At the same time, the phenolic hydroxyl groups in the reducing humic acid can also make the gel pores denser by forming hydrogen bonds.

[0032] Third, the present invention provides an application of the aforementioned hydrogel dressing in promoting healing of infected wounds.

[0033] The present invention innovatively introduces reducing humic acid, especially by increasing its phenolic hydroxyl content, to enhance its interaction with other polymers in the hydrogel (through hydrogen bonding or Schiff base cross-linking). Compared with the current hemostatic effect of sodium humate and collagen complexes, the present invention uses the phenolic hydroxyl groups of reducing humic acid to increase the cross-linking point density and structural stability of the hydrogel, while giving it stronger antioxidant, antibacterial and photothermal antibacterial functions. Compared with the existing use of Schiff base reaction to enhance the structural stability of hydrogels, the present invention introduces phenolic hydroxylated humic acid in the cross-linking process. The introduction of phenolic hydroxyl groups not only provides additional hydrogen bonding cross-linking, but also gives the hydrogel additional antioxidant, antibacterial and hemostatic functions.

[0034] The beneficial effects achieved by the present invention are:

[0035] (1) The reducing humic acid polysaccharide hydrogel dressing provided by the present invention has uniform pores in the internal structure, uniform pore size, high mechanical strength and excellent adhesion performance.

[0036] (2) The reducing humic acid polysaccharide hydrogel dressing provided by the present invention has an obvious hemostatic effect. The hydrogel dressing has high porosity and high specific surface area, which can concentrate the coagulation factors in the blood, and the reducing humic acid structure of the component contains a large number of phenolic hydroxyl groups, which can synergistically exert a hemostatic effect.

[0037] (3) The reducing humic acid polysaccharide hydrogel dressing provided by the present invention has a good antioxidant effect. The hydrogel contains reducing humic acid with antioxidant effect, and the phenolic hydroxyl group in the reducing humic acid can combine with free radicals to form an o-benzoquinone structure, thereby exerting the effect of free radical scavenging.

[0038] (4) The reducing humic acid polysaccharide hydrogel dressing provided by the present invention has excellent photothermal antibacterial effect. The hydrogel dressing has excellent photothermal heating effect at 808nm. The thermal effect can deform bacterial proteins and induce changes in bacterial cell membrane permeability, thereby causing bacterial death. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is the FTIR spectra of HA and HA-CHO;

[0040] Figure 2 PT and PT-NH 2 FTIR spectrum of

[0041] Figure 3 This is a scanning electron micrograph of the reducing humic acid polysaccharide hydrogel dressing;

[0042] Figure 4 It is the rheological data diagram of the reducing humic acid polysaccharide hydrogel dressing;

[0043] Figure 5 This is a graph showing the adhesion of the reducing humic acid polysaccharide hydrogel dressing to centrifuge tubes of different weights;

[0044] Figure 6 This is a diagram showing the adhesion of the reducing humic acid polysaccharide hydrogel dressing to pig skin;

[0045] Figure 7 This is a diagram showing the adhesion of the reducing humic acid polysaccharide hydrogel dressing to biological tissues;

[0046] Figure 8 is a graph showing the viscosity change of the reducing humic acid polysaccharide hydrogel dressing;

[0047] Fig. 9 is a graph of the phenolic hydroxyl content of the reducing humic acid polysaccharide hydrogel dressing;

[0048] Fig.10 This is a diagram of the free radical scavenging effect of the reducing humic acid polysaccharide hydrogel dressing;

[0049] Fig.11 It is the photothermal temperature rise curve of the reducing humic acid polysaccharide hydrogel dressing;

[0050] Fig.12 This is the cyclic light-heat curve of HUOH;

[0051] Fig.13 This is the light-to-heat conversion efficiency curve of HUOH;

[0052] Fig.14 This is a graph showing the killing effect of reducing humic acid polysaccharide hydrogel dressing on Staphylococcus aureus;

[0053] Fig.15 This is a diagram showing the therapeutic effect of reducing humic acid polysaccharide hydrogel dressing on cellular oxidative stress;

[0054] Fig.16 This is a diagram showing the hemostasis of the liver of mice by the reducing humic acid polysaccharide hydrogel dressing;

[0055] Fig.17 This is a graph showing the temperature rise of the reducing humic acid polysaccharide hydrogel dressing on the mouse skin surface;

[0056] Fig.18 This is a graph showing the killing effect of reducing humic acid polysaccharide hydrogel dressing on bacteria around mouse wounds;

[0057] Fig.19 This is a diagram showing how reducing humic acid polysaccharide hydrogel dressing promotes wound healing in mice. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0059] Example 1: Preparation of reducing humic acid

[0060] Weigh 1g humic acid and dissolve it in 120mL DDW, then divide it into 50mL centrifuge tubes, 30mL per tube and centrifuge at 12000rpm for 30min. Transfer the supernatant to a cellulose dialysis bag with a molecular weight of 1000Da and dialyze it for 24h. Freeze the solution at -80℃ and freeze dry it in a freeze dryer. The black powder obtained after freeze drying is the purified sodium humate (HU). Take 100mg of the purified HU in a 50mL beaker, then add 10mL 0.1M NaBH 4 The solution was reacted at 800 rpm and 40° C. for 4 h. After the reaction, the pH value was adjusted to 5.0 using 1 M HCl, and then dialyzed for 24 h and freeze-dried to obtain reduced humic acid (HUOH).

[0061] Example 2: Preparation of aldehyde-modified hyaluronic acid

[0062] Weigh 500 mg of hyaluronic acid (HA) in 50 mL of deionized water, stir magnetically until fully dissolved, and then weigh 282 mg of oxidant NaIO 4 Add to the above solution, react at room temperature, 800 rpm, and avoid light for 6 hours, then add 82 mg of ethylene glycol for 30 minutes to terminate the oxidation reaction. Place the solution after the reaction in a cellulose dialysis bag with a molecular weight of 3500, use a 2L dialysis system, and freeze the solution at -80°C after dialysis for 3 days, and then freeze-dry it in a freeze dryer. The spongy substance obtained after freeze-drying is aldehyde-modified hyaluronic acid (HA-CHO).

[0063] Example 3: Preparation of amino pectin

[0064] Weigh 1 g of pectin (PT) and dissolve it in 100 mL of deionized water. Then add 288 mg of NHS and 959 mg of EDC. Use acetic acid to adjust the pH value of the solution to about 4.0 and stir at room temperature for 2 hours. Then add 0.2 mL of ethylenediamine and react at 50 ° C for 48 hours. The product solution is dialyzed for 5 days. Finally, the dialyzed product is freeze-dried in a freeze dryer to obtain amino pectin (PT-NH 2 ).

[0065] Example 4: Preparation of reducing humic acid polysaccharide hydrogel dressing

[0066] HA-CHO, PT-NH 2 The HUOH solution was simply vortexed and mixed in a mass ratio of 20:20:1 to obtain a reducing humic acid polysaccharide hydrogel dressing (HA-PT / HUOH). 2 The hydrogel skeleton HA-PT obtained by Schiff base reaction, and the HA / PT obtained by directly mixing HA and PT.

[0067] Test example

[0068] 1. Synthesis characterization

[0069] The samples PT (pectin) and PT-NH were prepared by potassium bromide tableting method. 2 (amino pectin), HA (hyaluronic acid), HA-CHO (aldehyded hyaluronic acid), infrared spectra were measured using a Fourier transform infrared spectrometer. The results are as follows Figure 1 , 2 As shown, PT-NH 2 Successfully prepared with HA-CHO.

[0070] 2. Gel Characterization

[0071] The internal morphology of the hydrogel was observed by scanning electron microscopy (SEM). The hydrogel was frozen in a -80°C refrigerator and then transferred to a freeze dryer for freeze drying for 24 hours to obtain a freeze-dried gel. Each group of hydrogel samples was pasted on the conductive glue, and the surface adhesion part was cut off with a blade. Then, the sample was sprayed with gold by a gold sprayer and then placed in a SEM for pressure photography. During the photography process, the sample was always placed in a vacuum environment and the scanning electron microscope voltage was set to 2kV. The results are shown in Figure 2. Figure 3 As shown, the prepared reducing humic acid polysaccharide hydrogel dressing has uniform pores and uniform pore sizes in its internal structure.

[0072] The rheological properties of the hydrogel dressing were characterized by examining the changes in the storage modulus (G') and loss modulus (G") under angular frequency scanning mode. The gel dressing was placed on the sample plate of the rheometer, with a fixed amplitude of 0.5% and a frequency of 0.1-100 rad / s, and the rheological properties of the hydrogel dressing were examined. The results are shown in Figure 4 As shown, the prepared reducing humic acid polysaccharide hydrogel dressing has good rheological properties.

[0073] The shear thinning property of the hydrogel dressing was characterized by examining the change in viscosity of the gel at a shear rate of 0.1-100 (1 / s) at 37°C. In addition, the adhesion of the hydrogel dressing to centrifuge tubes of different weights, pig skin, and biological tissues was investigated. Figure 5 , 6, 7, and 8 show that the prepared reducing humic acid polysaccharide hydrogel dressing has good adhesion properties.

[0074] 3. Folin phenol method to measure phenolic hydroxyl content

[0075] The phenolic hydroxyl content of the product was detected by the Folin phenol method. 2 mL of DDW, 1 mL of sample (0.5 mg / mL), and 1 mL of 20% Folin phenol solution were added to a 10 mL EP tube, vortexed and mixed, and allowed to stand for 5 min. 1 mL of Na 2 CO 3 (7.5 mg / mL), keep in dark for 80 min, and measure the absorbance at 752 nm. Fig. 9 As shown, the prepared reducing humic acid polysaccharide hydrogel dressing has a higher phenolic hydroxyl content.

[0076] 4. Gel free radical scavenging experiment

[0077] Add 88 μL K to 5 mL ABTS (7 mM). 2 S 2 O 8 (140mM), prepared into ABTS stock solution, and kept at room temperature in the dark for 12-16h. Dilute the stock solution 80 times, take 100μL HU, HUOH, PH, HA-PT / HUOH (75μg / mL) and mix with 100μL working solution, and measure the absorbance as Ax. Take 100μL DDW and 100μL working solution as background, and measure the absorbance as A0. At the same time, mix 100μL of the above sample solution with 100μL DDW, and measure the absorbance as Ad. Each group of samples was measured three times in parallel, and the average value was calculated. The calculation formula is:

[0078] ABTS·+ clearance rate (%) = [A0-(Ax-Ad)] / A0×100%

[0079] The results are as follows Fig.10 As shown, the prepared reducing humic acid polysaccharide hydrogel dressing has good free radical scavenging ability.

[0080] 5. In vitro photothermal experiment of gel

[0081] The photothermal properties of humic acid enhance the antibacterial properties of the hydrogel. Humic acid dispersions of different concentrations were prepared: 100 μg / mL, 250 μg / mL, 500 μg / mL, with a wavelength of 808 nm and a power density of 2 W / cm 2 The near-infrared laser was used to irradiate solutions of different concentrations at 3.5 cm above the liquid surface. Pure water was used as the control group, and the temperature changes of the solutions were recorded by a thermal infrared imager. In addition, a 250 μg / mL humic acid solution was irradiated with a 808 nm laser (2 W / cm2 ) for 10 min, and then the hydrogel was allowed to cool naturally for 20 min. This process was repeated 4 times, and the solution temperature change was also recorded. The photothermal stability and photothermal conversion efficiency of the hydrogel were tested by photothermal cycle experiments. Fig.11 , 12 As shown in Figures 13, the prepared reducing humic acid polysaccharide hydrogel dressing has good photothermal stability and photothermal conversion efficiency.

[0082] 6. Antibacterial test of gel

[0083] Add 900 μL of bacterial suspension (1×10 6 CFU / mL), and 100 μL of HU, HUOH, HA-PT and HA-PT / HUOH with concentrations of 50 μg / mL, 100 μg / mL, 150 μg / mL, and 200 μg / mL were added in sequence. 100 μL of TSB culture medium was added to the blank group. The well plate was placed in a 37°C biochemical incubator for co-culture for 2 hours and then irradiated with a wavelength of 808 nm and a power density of 2 W / cm 2 After irradiation with near-infrared laser for 10 minutes, the cells were returned to the 37°C biochemical incubator for co-culture overnight. The next day, the culture medium of each group was taken out and diluted 10 4 Take 10 μL of each plate and inoculate it on TSA agar plate, put it back into the 37℃ biochemical incubator and invert it for 24 hours, then take pictures to record the growth of colonies. Fig.14 As shown, the prepared reducing humic acid polysaccharide hydrogel dressing has good antibacterial effect.

[0084] 7. Antioxidant test of gel

[0085] L929 cells were used to detect the level of cellular reactive oxygen species by flow cytometry. L929 cells in logarithmic phase were collected and the cell concentration was adjusted to 1.5×10 6 cells / mL, 1 mL of cells was inoculated into each well of a 12-well plate and incubated overnight. 2 O 2 (DMEM only) Stimulate for 1 h, discard H 2 O 2 1 mL HU, HUOH, HA-PT and HA-PT / HUOH were added respectively, incubated overnight, and then 20 mM DCFH-DA probe was diluted 6000 times with DMEM only medium, 1 mL dye solution was added to each well, and incubated for another 30 min. The dye solution was discarded, the cells were collected by digestion and centrifugation, washed twice with PBS, and finally the cell pellet was resuspended with 200 μL PBS, filtered through a cell screen, and detected by flow cytometry within 1 hour. The results are shown in Fig.15As shown, the prepared reducing humic acid polysaccharide hydrogel dressing has good antioxidant effect.

[0086] 8. Gel hemostasis experiment in mice liver

[0087] After anesthetizing the mice, the hair of the mice was removed to expose the upper abdomen. The skin was gently cut to expose the liver. Gauze was placed under the liver to absorb the extravasated peritoneal fluid, and then a pre-weighed filter paper was placed on it. The liver incision bleeding model was made with a scalpel and HA / PT, HA-PT and HA-PT / HUOH hydrogels were immediately administered for hemostasis (the dose of HA and HA-CHO was 400 μg / mouse; the dose of PT and PT-NH 2 The dose of HUOH was 400 μg / mouse; the dose of HUOH was 20 μg / mouse). After the bleeding from the liver incision stopped, the hemostasis time and the weight of the blood-containing filter paper were recorded. Fig.16 As shown, the prepared reducing humic acid polysaccharide hydrogel dressing has a good liver hemostatic effect.

[0088] 9. In vivo photothermal warming effect of gel

[0089] After the mice were anesthetized, the backs of the mice were depilated to expose the skin, and a 6 mm diameter skin punch was used to punch holes on the backs of the mice to establish a mouse skin injury model. 7 CFU / mL) was evenly dripped on the wound site, and the wound infection was observed the next day. The mice were randomly divided into 6 groups, namely Control group, HA-PT / HUOH group, Control+L group, HA / PT+L, HA-PT+L, HA-PT / HUOH+L group (the dose of HA and HA-CHO was 400 μg / mouse; the dose of PT and PT-NH 2 The dose of HUOH was 400 μg / mouse; the dose of HUOH was 20 μg / mouse; L represents 808 nm infrared laser treatment). After gel treatment, the light group was treated with 808 nm laser at 1.5 W / cm -2 The irradiation was carried out for 10 min at a power of 1000 W, and the real-time temperature was recorded using a thermal infrared imager. Fig.17 As shown, the prepared reducing humic acid polysaccharide hydrogel dressing has good photothermal conversion performance.

[0090] 10. Antibacterial and wound healing effects of gel in vivo

[0091] On the second day after the treatment, the skin tissue at the wound site was collected, cut into pieces, homogenized, and immersed in 500 μL of sterile TSB culture medium. Then 10 μL of the culture medium was evenly spread on the plate by plate coating, and inverted in a 37°C bacterial incubator overnight. The growth of the colony was recorded every other day. At the same time, the wound infection was recorded every 2 days from day 0 to day 12. Fig.18 , 19 As shown, the prepared reducing humic acid polysaccharide hydrogel dressing has good bactericidal and healing effects on mouse wounds.

Claims

1. A reducing humic acid polysaccharide hydrogel dressing, characterized in that: After being reductively modified, humic acid is reacted with aldehyde-modified polysaccharide and aminopolysaccharide through Schiff base to obtain hydrogel dressing; humic acid is modified with sodium borohydride.

2. The reducing humic acid polysaccharide hydrogel dressing according to claim 1, characterized in that: The mass ratio of humic acid to sodium borohydride is 10:1 to 100:

1.

3. The reducing humic acid polysaccharide hydrogel dressing according to claim 1, characterized in that: Aldehyde polysaccharide is a polysaccharide modified by sodium periodate, and the mass ratio of polysaccharide to sodium periodate is 10:1 to 100:

1.

4. The reducing humic acid polysaccharide hydrogel dressing according to claim 1 or 3, characterized in that: The polysaccharide in the aldehyde-modified polysaccharide includes at least one of hyaluronic acid, sodium alginate, artemisia annua polysaccharide and dextran.

5. The reducing humic acid polysaccharide hydrogel dressing according to claim 4, characterized in that: The polysaccharide in the aldehyde-formylated polysaccharide is hyaluronic acid.

6. The reducing humic acid polysaccharide hydrogel dressing according to claim 1, characterized in that: The amino polysaccharide includes at least one of gelatin, chitosan, and polysaccharide modified by ethylenediamine, and the mass ratio of the polysaccharide to the ethylenediamine is 10:1 to 100:

1.

7. The reducing humic acid polysaccharide hydrogel dressing according to claim 1 or 6, characterized in that: The polysaccharide in the aminopolysaccharide includes at least one of pectin, hyaluronic acid and sodium alginate.

8. The reducing humic acid polysaccharide hydrogel dressing according to claim 7, characterized in that: The polysaccharide in amino polysaccharides is pectin.

9. A method for preparing the reducing humic acid polysaccharide hydrogel dressing according to any one of claims 1 to 8, characterized in that: The steps include: After the S1 humic acid is purified, sodium borohydride is added to react, and the obtained product is freeze-dried to obtain reduced humic acid; The S2 polysaccharide was dissolved in deionized water, an oxidant was added to carry out an aldehyde reaction, and then ethylene glycol was added to terminate the oxidation reaction. The obtained product was purified by dialysis and freeze-dried to obtain the aldehyde polysaccharide; S3 polysaccharide was dissolved in N-hydroxybutyric acid imide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide, ethylenediamine was added to carry out an amination reaction, and the obtained product was purified by dialysis and freeze-dried to obtain an aminated polysaccharide; S4: Mixing reducing humic acid, aldehyde-modified polysaccharide and amino-modified polysaccharide to obtain a hydrogel dressing.

10. Use of the hydrogel dressing according to any one of claims 1 to 8, or the hydrogel dressing obtained by the preparation method according to claim 9, in promoting healing of infected wounds.

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