Exosome-containing composite dressing composition for promoting wound healing as well as preparation method and application of exosome-containing composite dressing composition

Abstract

The invention relates to the technical field of medical hydrogel, in particular to an exosome-containing composite dressing composition for promoting wound healing as well as a preparation method and application of the exosome-containing composite dressing composition. The composite dressing composition is prepared from the following raw materials: umbilical cord blood mesenchymal stem cell exosome, sanguisorba polysaccharide, hydroxy propyl cellulose, gelatin, tragacanth gum and water. The preparation method comprises the following steps: (1) adding water into the hydroxy propyl cellulose, the gelatin and the tragacanth gum, stirring and swelling to obtain a mixture; and (2) suspending the umbilical cord blood mesenchymal stem cell exosome in water, sequentially adding the umbilical cord blood mesenchymal stem cell exosome and sanguisorba officinalis polysaccharide into the mixture, and stirring and mixing to obtain the umbilical cord blood mesenchymal stem cell exosome. The composite dressing composition disclosed by the invention has relatively good antibacterial performance and wound healing promotion capability, provides a new idea for treatment of infected wounds, and has potential application prospects in the field of wound dressings.

Description

Technical Field

[0001] This invention relates to the field of medical hydrogel technology, specifically to a composite dressing composition containing exosomes that promotes wound healing, its preparation method, and its application. Background Technology

[0002] Wound healing is a complex physiological process involving multiple stages such as inflammation, proliferation, and tissue remodeling. While traditional wound dressings provide physical protection, they often lack bioactive functions that actively promote healing, leading to prolonged healing periods and increased risk of infection.

[0003] In recent years, extracellular vesicles, especially exosomes, have become a research hotspot in regenerative medicine due to their unique bioactivity. As natural carriers of intercellular communication, exosomes carry signaling molecules such as proteins, nucleic acids, and lipids, and can regulate cell proliferation, migration, and angiogenesis, showing great potential in tissue repair. However, the application of exosomes in wound dressings faces challenges: they are easily degraded rapidly by body fluids, resulting in insufficient local concentrations and difficulty in achieving slow release, thus affecting therapeutic efficacy. To address these issues, researchers have begun exploring the combination of exosomes with other biomaterials to construct composite dressings that combine sustained-release function and bioactivity.

[0004] Chinese invention patent application CN110755676A discloses a composite dressing for promoting wound healing and regeneration and loaded with traditional Chinese medicine exosomes, and its preparation method, including the following steps: reacting gelatin with methacrylic anhydride to prepare methacrylated gelatin; preparing traditional Chinese medicine exosomes by differential centrifugation; compounding the prepared exosomes with methacrylated gelatin, and adding SDF-1 and a photosensitizer to prepare a pre-gel system; and forming a composite dressing by ultraviolet light crosslinking. This invention claims that the prepared dressing is a novel photosensitive dressing composed of traditional Chinese medicine exosomes. After forming the pre-gel system, it can be crosslinked in vitro by ultraviolet light to form a composite dressing, or it can be crosslinked in situ at the wound site. The crosslinking is rapid, simple, and convenient, and can effectively protect the wound area.

[0005] Another Chinese invention patent application, CN111388740A, discloses a wound-healing dressing and its preparation method, comprising: (1) purification of α2 macroglobulin; (2) dissolving copper peptide, copper sulfate, leucopeptide, carboxymethyl chitosan, and polyethylene oxide in water, stirring evenly, adding the α2 macroglobulin solution to obtain a spinning solution; and (3) electrospinning the spinning solution to obtain the wound-healing dressing. The wound-healing dressing prepared by this invention is a medical material that can induce wound healing for a long time, accelerate wound healing, and is very effective in treating wounds and skin injuries.

[0006] Existing technologies have been explored to some extent for wound healing dressings and dressings loaded with traditional Chinese medicine exosomes, and some results have been achieved. However, their preparation methods are generally quite complex, and their efficacy needs to be improved. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a composite dressing composition containing exosomes that promotes wound healing, its preparation method, and its application.

[0008] The objective of this invention is achieved through the following technical solution: A composite dressing composition containing exosomes to promote wound healing, the raw materials of the composite dressing composition being: umbilical cord blood mesenchymal stem cell exosomes, Sanguisorba officinalis polysaccharide, hydroxypropyl cellulose, gelatin, tragacanth gum, and water.

[0009] In some embodiments of the present invention, the raw materials of the composite dressing, by weight, are: 5-10 parts of umbilical cord blood mesenchymal stem cell exosomes, 1-5 parts of Sanguisorba officinalis polysaccharide, 1-5 parts of hydroxypropyl cellulose, 1-5 parts of gelatin, 1-5 parts of tragacanth gum, and 70-90 parts of water.

[0010] In some embodiments of the present invention, the preparation of the umbilical cord blood mesenchymal stem cell exosomes includes: (1) diluting the umbilical cord blood, centrifuging it twice, washing it, and discarding the supernatant to obtain mononuclear cells; (2) then culturing the mononuclear cells to obtain cultured cells; and (3) extracting the exosomes from the cultured cells to obtain the product.

[0011] In some embodiments of the present invention, the solvent used for dilution in step (1) is PBS, the rotation speed of the first centrifugation is 1500-2500 rpm, the time of the first centrifugation is 5-15 min, after the first centrifugation, the white membrane layer is taken, and lymphocyte separation solution and sodium chloride solution are added respectively, the rotation speed of the second centrifugation is 2000-3000 rpm, the time of the second centrifugation is 25-35 min, and the washing reagent is PBS.

[0012] In some embodiments of the present invention, in step (2), the culture medium used for culturing is DMEM medium containing 10% FBS, and the inoculation density during culturing is 5 × 10⁻⁶. 3 -1×10 4 nucleated cells / cm 2 .

[0013] In some embodiments of the present invention, the extraction method in step (3) is as follows: the supernatant of the cultured cells is centrifuged sequentially as follows: centrifuged at 250-350×g for 8-12 min to obtain supernatant a, and cells and large particulate impurities are removed; supernatant a is transferred to an ultracentrifuge tube and centrifuged at 14000-16000×g for 30-40 min to obtain supernatant b, and dead cells and debris are removed; supernatant b is centrifuged at 90000-110000×g for 70-80 min, the supernatant is discarded, and the precipitate is collected.

[0014] In some embodiments of the present invention, the preparation of the Sanguisorba officinalis polysaccharide includes extracting Sanguisorba officinalis with water and precipitating it with ethanol to obtain the Sanguisorba officinalis polysaccharide.

[0015] In some embodiments of the present invention, the preparation of the Sanguisorba officinalis polysaccharide includes: pulverizing Sanguisorba officinalis to 20-40 mesh, adding 5-10 times the weight of water to Sanguisorba officinalis, extracting at 60-80℃ for 1-3 hours, extracting 1-3 times, combining the extracts, concentrating under reduced pressure to 1 / 5-1 / 3 of the original volume, and then adding ethanol for precipitation: first adding ethanol to the volume concentration of ethanol to 60-70%, letting stand for 12-24 hours for ethanol precipitation, filtering and collecting the supernatant; continuing to add ethanol to the supernatant to the volume concentration of ethanol to 80-90%, letting stand for 12-24 hours for ethanol precipitation, filtering and collecting the precipitate; combining the two precipitates, and vacuum drying at 60℃ to constant weight to obtain Sanguisorba officinalis polysaccharide.

[0016] In some embodiments of the present invention, the alcohol precipitation is performed by first adding ethanol until the volume concentration of ethanol is 65%, then adding ethanol to the supernatant until the volume concentration of ethanol is 85%, then precipitating again, and combining the two precipitates.

[0017] A second objective of this invention is to provide a method for preparing the aforementioned composite dressing composition, comprising the following steps: S1. Hydroxypropyl cellulose, gelatin, and tragacanth gum are mixed with water and stirred until swollen to obtain a mixture; S2. Suspend umbilical cord blood mesenchymal stem cell exosomes in water, and then add them sequentially to the mixture along with Sanguisorba officinalis polysaccharide and stir to mix.

[0018] Preferably, the stirring temperature in step S1 is 32-37℃; the stirring temperature in step S2 is to first stir at 40-45℃ for 10-20 minutes, and then stir at 30-35℃ for 20-40 minutes.

[0019] A third objective of this invention is to provide the use of the aforementioned composite dressing composition in the preparation of products that promote wound healing.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention uses umbilical cord blood mesenchymal stem cell exosomes as the core active ingredient, which, when combined with Sanguisorba officinalis polysaccharide, can synergistically and significantly improve the healing effect of skin wounds.

[0021] (2) The present invention uses Sanguisorba officinalis polysaccharide, which not only promotes the swelling effect of gelatin and improves the stability of gel, but also shows that Sanguisorba officinalis polysaccharide can also improve the long-term slow release of exosomes of umbilical cord blood mesenchymal stem cells, improve the duration of drug efficacy, shorten the healing time, and can also stop bleeding and reduce inflammation.

[0022] (3) The present invention uses high-speed centrifugation to extract and purify umbilical cord blood mesenchymal stem cell exosomes. The process is relatively simple and can effectively obtain highly active exosomes, making the prepared dressing composition more effective. The present invention explored the extraction process of Sanguisorba officinalis polysaccharide and found that using fractional precipitation to obtain polysaccharides of a specific molecular weight can improve the overall efficacy of Sanguisorba officinalis polysaccharide in the present invention.

[0023] (4) The present invention uses tragacanth gum in combination with hydroxypropyl cellulose. Compared with gelatin, it can better assist in improving the release of active ingredients and promote skin penetration, and can improve antibacterial activity to a certain extent. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are not intended to limit the present invention, but only to illustrate the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are generally performed under conventional conditions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0025] Example 1 A composite dressing composition containing exosomes to promote wound healing, wherein the raw materials of the composite dressing are, by weight: 8 parts of umbilical cord blood mesenchymal stem cell exosomes, 2 parts of Sanguisorba officinalis polysaccharide, 3 parts of hydroxypropyl cellulose, 2 parts of gelatin, 3 parts of tragacanth gum, and 80 parts of water.

[0026] The method for preparing the umbilical cord blood mesenchymal stem cell exosomes is as follows: (1) Add an equal volume of PBS to the umbilical cord blood for dilution and centrifuge twice: the first centrifugation speed is 2000 rpm and the first centrifugation time is 10 min. After the first centrifugation, take the white membrane layer and add lymphocyte separation solution and sodium chloride solution respectively. The second centrifugation speed is 2500 rpm and the second centrifugation time is 30 min. Take the mononuclear cell layer, wash it three times with an equal volume of PBS, and discard the supernatant to obtain mononuclear cells.

[0027] (2) Then, the mononuclear cells were cultured in DMEM medium with 10% FBS at 37°C and 5% carbon dioxide until 80% adherent growth was achieved. The inoculation density during culture was 5 × 10⁶ cells / year. 3 nucleated cells / cm 2 .

[0028] (3) Extraction of exosomes from cultured cells: Collect cell culture supernatant and perform the following centrifugation treatments in sequence: centrifuge at 300×g for 10min, discard the precipitate, and obtain supernatant a; centrifuge at 15,000×g for 35min, discard the precipitate, and obtain supernatant b; centrifuge at 100,000×g for 75min, discard the supernatant, collect the precipitate, and obtain umbilical cord blood mesenchymal stem cell exosomes.

[0029] Preparation of Sanguisorba officinalis polysaccharide: Sanguisorba officinalis powder was added to 8 times its weight of water and extracted at 70℃ for 2 hours. The extraction was repeated twice. The extracts were combined and concentrated under reduced pressure to 1 / 4 of the original volume. Then, ethanol was added for precipitation: ethanol was added until the volume concentration of ethanol was 65%, and the mixture was allowed to stand for 14 hours for precipitation. The supernatant was then filtered and collected. Ethanol was added to the supernatant until the volume concentration of ethanol was 85%, and the mixture was allowed to stand for 14 hours for precipitation. The precipitate was then collected by filtration. The two precipitates were combined and vacuum dried at 60℃ to constant weight to obtain Sanguisorba officinalis polysaccharide.

[0030] The preparation method of the composite dressing composition includes the following steps: S1. Add water to hydroxypropyl cellulose, gelatin and tragacanth gum, stir at 35°C and 200 rpm for 45 min to swell and obtain a mixture; S2. Suspend the exosomes of umbilical cord blood mesenchymal stem cells in water, and then add them sequentially to the mixture with Sanguisorba officinalis polysaccharide and stir (first stir at 42℃ and 300rpm for 15min, then stir at 32℃ and 300rpm for 25min) to obtain the final product.

[0031] Example 2 A composite dressing composition containing exosomes to promote wound healing, wherein the raw materials of the composite dressing are, by weight, 5 parts of umbilical cord blood mesenchymal stem cell exosomes, 1 part of Sanguisorba officinalis polysaccharide, 1 part of hydroxypropyl cellulose, 1 part of gelatin, 1 part of tragacanth gum and 70 parts of water.

[0032] The method for preparing the umbilical cord blood mesenchymal stem cell exosomes is as follows: (1) Add an equal volume of PBS to the umbilical cord blood for dilution and centrifuge twice: the first centrifugation speed is 1500 rpm and the first centrifugation time is 15 min. After the first centrifugation, take the white membrane layer and add lymphocyte separation solution and sodium chloride solution respectively. The second centrifugation speed is 2000 rpm and the second centrifugation time is 35 min. Take the mononuclear cell layer, wash it three times with an equal volume of PBS, and discard the supernatant to obtain mononuclear cells.

[0033] (2) Then, the mononuclear cells were cultured in DMEM medium with 10% FBS at 37°C and 5% carbon dioxide until 80% adherent cells were grown. The inoculation density during culture was 6 × 10⁶ cells / year. 3 nucleated cells / cm 2 .

[0034] (3) Extraction of exosomes from cultured cells: Collect cell culture supernatant and perform the following centrifugation treatments in sequence: centrifuge at 300×g for 10min, discard the precipitate, and obtain supernatant a; centrifuge at 15,000×g for 35min, discard the precipitate, and obtain supernatant b; centrifuge at 100,000×g for 75min, discard the supernatant, collect the precipitate, and obtain umbilical cord blood mesenchymal stem cell exosomes.

[0035] Preparation of Sanguisorba officinalis polysaccharide: Sanguisorba officinalis powder was added to 5 times its weight of water and extracted at 60℃ for 3 hours. The extraction was repeated once. The extract was concentrated under reduced pressure to 1 / 5 of its original volume, and then ethanol was added for precipitation: ethanol was first added until the volume concentration of ethanol was 60%, and the mixture was allowed to stand for 24 hours for precipitation. The supernatant was then filtered and collected. Ethanol was added to the supernatant until the volume concentration of ethanol was 80%, and the mixture was allowed to stand for 24 hours for precipitation. The precipitate was then collected by filtration. The two precipitates were combined and vacuum dried at 60℃ to constant weight to obtain Sanguisorba officinalis polysaccharide.

[0036] The preparation method of the composite dressing composition includes the following steps: S1. Add water to hydroxypropyl cellulose, gelatin and tragacanth gum, stir at 32°C and 100 rpm for 60 min to swell and obtain a mixture; S2. Suspend umbilical cord blood mesenchymal stem cell exosomes in water, and then add them sequentially to the mixture with Sanguisorba officinalis polysaccharide and stir (first stir at 40℃ and 200 rpm for 20 min, then stir at 35℃ and 200 rpm for 20 min) to obtain the final product.

[0037] Example 3 A composite dressing composition containing exosomes to promote wound healing, wherein the raw materials of the composite dressing are, by weight, 10 parts of umbilical cord blood mesenchymal stem cell exosomes, 5 parts of Sanguisorba officinalis polysaccharide, 5 parts of hydroxypropyl cellulose, 5 parts of gelatin, 5 parts of tragacanth gum, and 90 parts of water.

[0038] The method for preparing the umbilical cord blood mesenchymal stem cell exosomes is as follows: (1) Add an equal volume of PBS to the umbilical cord blood for dilution and centrifuge twice: the first centrifugation speed is 2500 rpm and the first centrifugation time is 5 min. After the first centrifugation, take the white membrane layer and add lymphocyte separation solution and sodium chloride solution respectively. The second centrifugation speed is 3000 rpm and the second centrifugation time is 25 min. Take the mononuclear cell layer, wash it three times with an equal volume of PBS, and discard the supernatant to obtain mononuclear cells. (2) The mononuclear cells were then cultured in DMEM medium containing 10% FBS at 37°C until 80% adherent cells were formed. The seeding density during culture was 5 × 10⁶ cells / year. 3 nucleated cells / cm 2 .

[0039] (3) Extraction of exosomes from cultured cells: Collect cell culture supernatant and perform the following centrifugation treatments in sequence: centrifuge at 300×g for 10min, discard the precipitate, and obtain supernatant a; centrifuge at 15,000×g for 35min, discard the precipitate, and obtain supernatant b; centrifuge at 100,000×g for 75min, discard the supernatant, collect the precipitate, and obtain umbilical cord blood mesenchymal stem cell exosomes.

[0040] Preparation of Sanguisorba officinalis polysaccharide: Sanguisorba officinalis was pulverized, and water with a mass of 10 times that of Sanguisorba officinalis was added. The mixture was extracted at 80℃ for 1 hour, and the extraction was repeated twice. The extracts were combined and concentrated under reduced pressure to 1 / 3 of the original volume. Then, ethanol was added for precipitation: ethanol was first added until the volume concentration of ethanol was 70%, and the mixture was allowed to stand for 12 hours for precipitation. The supernatant was then filtered and collected. Ethanol was added to the supernatant until the volume concentration of ethanol was 90%, and the mixture was allowed to stand for 12 hours for precipitation. The precipitate was then collected by filtration. The two precipitates were combined and vacuum dried at 60℃ to constant weight to obtain Sanguisorba officinalis polysaccharide.

[0041] The preparation method of the composite dressing composition includes the following steps: S1. Add water to hydroxypropyl cellulose, gelatin and tragacanth gum, stir at 37°C and 300 rpm for 30 min to swell and obtain a mixture; S2. Suspend the exosomes of umbilical cord blood mesenchymal stem cells in water, and then add them sequentially to the mixture with Sanguisorba officinalis polysaccharide and stir (stir at 45℃ and 300rpm for 10min, then at 30℃ and 300rpm for 40min) to obtain the final product.

[0042] Comparative Example 1 The only difference between this comparative example and Example 1 is that the umbilical cord blood mesenchymal stem cell exosomes were replaced with an equal mass of Sanguisorba officinalis polysaccharide.

[0043] Comparative Example 2 The only difference between this comparative example and Example 1 is that the Sanguisorba officinalis polysaccharide was replaced with an equal mass of umbilical cord blood mesenchymal stem cell exosomes.

[0044] Comparative Example 3 The only difference between this comparative example and Example 1 is the preparation method of Sanguisorba officinalis polysaccharide. Specifically, after extracting Sanguisorba officinalis under the water extraction conditions of Example 1, ethanol was added to the solution until the ethanol concentration was 75%. The solution was allowed to stand for 14 hours for alcohol precipitation. The precipitate was collected and dried to obtain the polysaccharide (single precipitation method). The remaining components, dosages, and preparation methods were the same as in Example 1.

[0045] Comparative Example 4 The only difference between this comparative example and Example 1 is that the excipients of the composite dressing composition are different; specifically, tragacanth gum is replaced with an equal mass of gelatin.

[0046] Comparative Example 5 The only difference between this comparative example and Example 1 is that the umbilical cord blood mesenchymal stem cell exosomes were replaced with an equal mass of adipose-derived mesenchymal stem cell exosomes extracted using ultrafiltration.

[0047] Comparative Example 6 The only difference between this comparative example and Example 1 is that the amount of umbilical cord blood mesenchymal stem cell exosomes in the composite dressing composition is 2 parts, while the other components and amounts are the same as in Example 1.

[0048] All ethanol concentrations mentioned above are volume concentrations.

[0049] Effect test Test Example 1: Antibacterial Experiment The above-prepared dressing was subjected to antibacterial experiments, including an inhibition zone test, with a concentration of 10... 7 A bacterial suspension of Staphylococcus aureus at approximately CFU / mL was evenly spread on the surface of sterilized agar medium. Then, an equal dose (0.5 g / tablet) of the above-mentioned dressing composition was added to the medium. The positive control group used a standard dressing tablet containing 1% silver sulfadiazine (0.5 g / tablet), while positive control group 2 used a commercially available dressing tablet containing recombinant human epidermal growth factor (0.5 g / tablet). The medium was then incubated at 37°C for 24 hours. The diameter of the inhibition zone was measured using the cross-sectional method (three parallel samples were set for each group, and the average value was taken). The results are shown in Table 1. A larger inhibition zone diameter indicates a stronger antibacterial effect.

[0050] Table 1 Results of antibacterial experiment

[0051] Test Example 2: Drug Efficacy Experiment Forty-two male SD rats weighing 200-220g were selected and fed freely for two days. On the day of the experiment, the rats were randomly divided into seven groups. Each rat was anesthetized by intraperitoneal injection of 0.8mL of 20wt% urethane. After the rats were completely unconscious, they were placed back-up on the operating table, and hair removal cream was applied to their lower backs for hair removal. The shaved skin was disinfected with medical alcohol swabs, and a 1cm incision was made longitudinally along the erector spinae muscle using medical scissors. Immediately afterward, the composite dressing compositions prepared in Examples 1-3 and Comparative Examples 1-4 were applied to the incisions of different groups of rats. Positive control group 1 used a standard dressing sheet containing 1% silver sulfadiazine (0.5g / sheet), and positive control group 2 used a commercially available dressing sheet containing recombinant human epidermal growth factor (0.5g / sheet). The dressings were changed daily, and the outside was bandaged with medical gauze. The incisions were observed and the gauze was changed every two days, but the dressings were not changed. The time it took for the wound to fully heal (the healed wound was smooth, without redness, swelling, pain, or exudate) was recorded, and the results are shown in Table 2.

[0052] Table 2 Results of the pharmacodynamic experiment

[0053] Note: Compared with Example 1 group ▲ P < 0.05 ▲▲ P < 0.01; compared with Example 2 group, # P < 0.05 ## P < 0.01; compared with Example 3 group, & P < 0.05 && P < 0.01.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A composite dressing composition containing exosomes to promote wound healing, characterized in that, The specific raw materials of the composite dressing composition are: umbilical cord blood mesenchymal stem cell exosomes, Sanguisorba officinalis polysaccharide, hydroxypropyl cellulose, gelatin, tragacanth gum, and water.

2. The composite dressing composition according to claim 1, characterized in that, The raw materials of the composite dressing composition, by weight, are: 5-10 parts of umbilical cord blood mesenchymal stem cell exosomes, 1-5 parts of Sanguisorba officinalis polysaccharide, 1-5 parts of hydroxypropyl cellulose, 1-5 parts of gelatin, 1-5 parts of tragali gum, and 70-90 parts of water.

3. The composite dressing composition according to claim 1, characterized in that, The preparation of the umbilical cord blood mesenchymal stem cell exosomes includes: (1) diluting the umbilical cord blood, centrifuging it twice, washing it, and discarding the supernatant to obtain mononuclear cells; (2) then culturing the mononuclear cells to obtain cultured cells; (3) extracting the exosomes from the cultured cells to obtain the cells.

4. The composite dressing composition according to claim 3, characterized in that, The solvent used for dilution in step (1) is PBS. The first centrifugation speed is 1500-2500 rpm and the first centrifugation time is 5-15 min. After the first centrifugation, the white membrane layer is taken and lymphocyte separation solution and sodium chloride solution are added respectively. The second centrifugation speed is 2000-3000 rpm and the second centrifugation time is 25-35 min. The washing reagent is PBS. And / or, in step (2), the culture medium used for cultivation is DMEM medium containing 10% FBS, and the inoculation density during cultivation is 5 × 10⁻⁶. 3 -1×10 4 nucleated cells / cm 2 .

5. The composite dressing composition according to claim 4, characterized in that, The extraction method described in step (3) is as follows: the supernatant of the cultured cells is centrifuged sequentially as follows: centrifuged at 250-350×g for 8-12 min to obtain supernatant a; supernatant a is centrifuged at 14000-16000×g for 30-40 min to obtain supernatant b; supernatant b is centrifuged at 90000-110000×g for 70-80 min, the supernatant is discarded, and the precipitate is collected.

6. The composite dressing composition according to claim 1, characterized in that, The preparation of the Sanguisorba officinalis polysaccharide includes: adding water to Sanguisorba officinalis, extracting at 60-80℃ for 1-3 hours, extracting 1-3 times, combining the extracts, concentrating and then adding ethanol for precipitation.

7. The composite dressing composition according to claim 6, characterized in that, The amount of water added is 5-10 times the mass of Sanguisorba officinalis. The alcohol precipitation is performed by first adding ethanol until the volume concentration of ethanol is 60-70%, letting it stand for 12-24 hours for alcohol precipitation, taking the supernatant, adding ethanol until the volume concentration of ethanol is 80-90%, letting it stand for 12-24 hours for alcohol precipitation, combining the two precipitates, and drying them to obtain the final product.

8. A method for preparing the composite dressing composition according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Hydroxypropyl cellulose, gelatin, and tragacanth gum are mixed with water and stirred until swollen to obtain a mixture; S2. Suspend umbilical cord blood mesenchymal stem cell exosomes in water, and then add them sequentially to the mixture along with Sanguisorba officinalis polysaccharide and stir to mix.

9. The preparation method according to claim 8, characterized in that, The stirring temperature in step S1 is 32-37℃; the stirring temperature in step S2 is to first stir at 40-45℃ for 10-20 minutes, and then stir at 30-35℃ for 20-40 minutes.

10. The use of the composite dressing composition according to any one of claims 1-7 in the preparation of a product that promotes wound healing.

Images