Nampt-rich wound repair exosome hydrogel and preparation method thereof

Abstract

The invention relates to the technical field of medical engineering, and discloses a nampt-rich wound repair exosome hydrogel and a preparation method thereof.The preparation method comprises the following preparation steps that mesenchymal stem cells are adopted to extract exosomes, and mesenchymal stem cell exosomes are obtained; the preparation method comprises the following steps: mixing and reacting nampt, astragaloside, medium chain triglyceride and soybean phospholipid to obtain lipid nanoparticles; mixing the lipid nanoparticles with the mesenchymal stem cell exosome to obtain an exosome loaded with the lipid nanoparticles; mixing the exosome loaded with the lipid nanoparticles, a cabbage extract and a polysaccharide extract to obtain a compound; the compound, a chitosan solution and a beta-sodium glycerophosphate solution are mixed, and the wound repair exosome hydrogel rich in nampt is obtained. The loaded lipid nanoparticles, the cabbage extract and the polysaccharide extract are compounded to serve as a wound repairing medicine, and the wound repairing medicine is added into the hydrogel to serve as a wound repairing agent, so that the wound repairing capacity can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of medical engineering technology, and specifically relates to a wound-repairing exosome hydrogel rich in NAMPT and a preparation method thereof. Background Art

[0002] Trauma refers to the state of tissue surface defect caused by abrasions, lacerations, cuts, contusions, and burns. Trauma repair is completed by filling, connecting or replacing the defective tissue with cells and intercellular matrix that proliferate after the injury. Exosomes are nanoscale cellular vesicles with intercellular communication function. They are lipid bilayer membrane-bound vesicles released into the extracellular space by cells under static or stress conditions. They can carry a variety of bioactive molecules such as proteins, mRNA and miRNA, and play an important role in intercellular communication and signal transduction, such as immune regulation, tumor occurrence, angiogenesis and tissue healing, trauma repair, etc.

[0003] Exosomes have a relatively short half-life, poor accumulation, and fast clearance rate, which leads to limitations in the application of exosomes in wound repair. NAMPT (nicotinamide phosphoribosyltransferase) can provide energy during cell repair at the wound site and contribute to the healing of cells at the wound site, but when NAMPT is loaded into exosomes, it has poor stability and is easily released, affecting bioavailability and wound treatment effects. Summary of the invention

[0004] The present invention provides a wound repairing exosome hydrogel rich in NAMPT and a preparation method thereof, which solves the problems of relatively short half-life, poor accumulation, fast clearance rate of exosomes and poor stability of NAMPT and easy release affecting wound repair.

[0005] The technical solution of the present invention:

[0006] A method for preparing a wound repair exosome hydrogel rich in NAMPT comprises the following preparation steps:

[0007] S1. extracting exosomes from mesenchymal stem cells to obtain mesenchymal stem cell exosomes;

[0008] S2. mixing nampt, astragaloside IV, medium chain triglyceride and soybean lecithin to obtain lipid nanoparticles;

[0009] S3. mixing the lipid nanoparticles with the mesenchymal stem cell exosomes to obtain exosomes loaded with the lipid nanoparticles;

[0010] S4. mixing the exosomes loaded with lipid nanoparticles, the cabbage extract, and the polysaccharide extract to obtain a complex;

[0011] S5. Mix the complex, chitosan solution, and sodium β-glycerophosphate solution, and stir at 36-38° C. for 5-10 minutes to obtain a wound-repairing exosome hydrogel rich in NAMPT.

[0012] Furthermore, the mass ratio of exosomes loaded with lipid nanoparticles, cabbage extract, and polysaccharide extract is (0.5-1):(0.2-0.4):(0.1-0.3).

[0013] Furthermore, the dosage ratio of the complex, chitosan solution, and β-sodium glycerophosphate solution is (0.06-0.1) g: (6-8) mL: (0.5-1.5) mL.

[0014] Furthermore, step S5 is specifically as follows: adding 0.2 g of chitosan to 10 mL of acetic acid solution with a mass fraction of 0.1-0.2%, stirring evenly to obtain a chitosan solution, mixing 7 mL of the chitosan solution and 1 mL of 0.5-1.5 g / mL sodium β-glycerophosphate solution, stirring evenly, adding a sodium bicarbonate aqueous solution with a concentration of 0.4-0.6 mol / L and the complex, stirring at 36-38°C for 5-10 min, and obtaining a wound repair exosome hydrogel rich in nampt.

[0015] Furthermore, the dosage ratio of chitosan to acetic acid solution is (0.1-0.3) g: (8-12) mL.

[0016] Furthermore, the molecular weight of chitosan is 0.7-1×10 6 , Tianjin Xiensi Biochemical Technology Co., Ltd.

[0017] Furthermore, the exosomes loaded with lipid nanoparticles are prepared by the following steps:

[0018] A1. Cultivate mesenchymal stem cells using a serum-free culture system for primary mesenchymal stem cells. When the cells grow to a fusion rate of 80-81%, subculture them. Take the culture medium of mesenchymal stem cells cultured to the 3rd to 5th generation and place it in a centrifuge tube. Centrifuge to collect the cell supernatant. After filtering the cell supernatant with a 0.2-0.23 μm filter membrane, centrifuge to collect the exosome precipitate, add a phosphate buffer solution, and obtain the mesenchymal stem cell exosomes, which are then stored at -(70-90)°C.

[0019] A2. Astragaloside IV was added to anhydrous ethanol, stirred evenly, and after removing the ethanol by rotary evaporation at 80-90°C, a 0.3-0.7% polyoxyethylene stearate solution and nampt were added, and ultrasonicated at 180-220W for 5-7s to obtain a colloid;

[0020] A3. Add medium chain triglycerides and soybean lecithin to deionized water, stir evenly, add colloid, stir at 500-700 rpm for 25-35 min, and freeze-dry to obtain lipid nanoparticles;

[0021] A4. Mix the lipid nanoparticles with the mesenchymal stem cell exosomes, stir at 36-38°C for 1-2h, add a sodium chloride solution with a mass fraction of 0.9-1.1%, and filter through a 100-120KDa ultrafiltration tube to obtain exosomes loaded with lipid nanoparticles.

[0022] Furthermore, during the above-mentioned A1 reaction process, mesenchymal stem cells were centrifuged to collect the cell supernatant to remove smaller impurities such as cell debris and free proteins, and filtered with a 0.22 μm filter screen to remove tiny impurities. The de1 exosome precipitate was collected by centrifugation and resuspended in a phosphate buffer solution to obtain mesenchymal stem cell exosomes.

[0023] Furthermore, in the above-mentioned A2 reaction process, astragaloside IV is dissolved in anhydrous ethanol, which can effectively dissolve astragaloside IV, and ethanol can be removed by rotary evaporation at 80-90°C to form an astragaloside IV concentrate. After ultrasonic treatment, polyoxyethylene stearate can penetrate into the astragaloside IV concentrate to form an astragaloside IV colloid, and nampt is added to the astragaloside IV colloid. The benzene ring and lipid structure carried by nampt can be combined with the benzene ring and hydroxyl group on the astragaloside IV colloid molecule in the astragaloside IV colloid solution through hydrogen bonds, so that nampt is dispersed in the astragaloside IV colloid, which is beneficial to the encapsulation of nampt in lipid nanoparticles and improves the stability of nampt in the hydrogel.

[0024] Furthermore, during the above-mentioned A3 reaction, medium-chain triglycerides can interact with soybean lecithin to form a lipid bilayer structure with a cavity structure, and during the formation of the lipid bilayer structure, the colloid dispersed with nampt can be embedded in the cavity of the lipid bilayer structure, so that nampt is embedded in the lipid nanoparticles to form lipid nanoparticles.

[0025] Furthermore, during the above-mentioned A4 reaction process, exosomes also have a unique phospholipid bilayer structure similar to that of liposomes, and have good biocompatibility with lipid nanoparticles containing a lipid bilayer structure, so that the exosome membrane proteins are adsorbed to the surface of the lipid nanoparticles, thereby achieving exosome encapsulation of lipid nanoparticles to form exosomes loaded with lipid nanoparticles.

[0026] Furthermore, in step A1, the culture conditions are specifically: 36-38°C, containing 4-6% carbon dioxide, and saturated humidity; the centrifugal collection of cell supernatant is specifically: the centrifugal temperature is 3-5°C, 300×g centrifugation for 8-12min; 2000×g centrifugation for 15-25min; 10000×g centrifugation for 25-35min.

[0027] Furthermore, in step A2, the dosage ratio of astragaloside IV, anhydrous ethanol, polyoxyethylene stearate solution, and nampt is (0.03-0.07) g: (8-12) mL: (3-7) mL: (0.02-0.04) g.

[0028] Furthermore, in step A3, the ratio of the medium chain triglyceride, soybean lecithin, deionized water, and colloid is (0.5-1.5) g: (2-4) g: (15-25) mL: (0.2-0.3) g.

[0029] Furthermore, in step A4, the ratio of the lipid nanoparticles, mesenchymal stem cell exosomes, and sodium chloride solution is (0.3-0.5) g: (8-12) mL: (0.01-0.03) mL.

[0030] Furthermore, the cabbage extract is specifically prepared by the following steps:

[0031] The cabbage is washed with deionized water to remove impurities, dried, and then crushed in a crusher. The crushed cabbage is added to an ethanol aqueous solution with a mass fraction of 75-85%, ultrasonically treated for 25-35 minutes, centrifuged at 300-400 rpm for 10-15 minutes, the supernatant is collected, and vacuum concentrated to obtain a cabbage extract.

[0032] Furthermore, the ratio of the crushed cabbage to the ethanol aqueous solution is (0.3-0.7) g: (8-12) mL.

[0033] Furthermore, the polysaccharide extract is specifically prepared by the following steps:

[0034] The freeze-dried aloe vera gel is added to deionized water, stirred evenly, and after ultrasonic treatment, the supernatant is collected by centrifugation, and the supernatant is added to anhydrous ethanol, allowed to stand, and the precipitate is collected and freeze-dried to obtain a polysaccharide extract.

[0035] Furthermore, the usage ratio of freeze-dried aloe vera gel to deionized water is (0.5-1.5) g:(80-120) mL.

[0036] Furthermore, the ratio of supernatant to anhydrous ethanol is (8-12) g:(25-35) mL.

[0037] The present invention has the following beneficial effects:

[0038] (1) In the technical scheme of the present invention, NAMPT is dispersed in astragaloside colloid, and NAMPT can be encapsulated in lipid nanoparticles, which is beneficial to improving the stability of NAMPT in hydrogel, and astragaloside colloid can significantly promote the migration of keratinocytes and promote angiogenesis, thereby promoting wound repair; the colloid dispersed with NAMPT is embedded in the cavity of the lipid bilayer structure to form lipid nanoparticles. The small size structure of the formed lipid nanoparticles can effectively deliver NAMPT to the wound site, and can protect NAMPT from degradation in the body environment, thereby improving the bioavailability and therapeutic effect of NAMPT.

[0039] (2) In the technical solution of the present invention, nampt can participate in NAD + Biosynthesis of nicotinamide adenine dinucleotide, NAD + It is a key coenzyme for intracellular energy metabolism and redox reactions, providing energy for cells, and NAD + It has a very important regulatory ability for the wound healing process. Applying NAMPT to wound repair can provide energy for wound cell repair and maintain the normal physiological function of cells, which helps the healing of wound cells.

[0040] (3) In the technical solution of the present invention, the use of exosomes to embed lipid nanoparticles can effectively alleviate the release and degradation of lipid nanoparticles, further prolong the bioavailability and therapeutic effect of lipid nanoparticle drugs, and has a synergistic effect with lipid nanoparticles in protecting nampt from degradation in the body environment and prolonging the wound repair effect. In addition, exosomes exhibit intercellular communication through exocytosis and endocytosis pathways, and can be natural carriers for delivering proteins and nucleic acids between cells. They can be absorbed into the cell population at the wound site, participate in the activation of the immune system and tissue regeneration, and perform wound repair.

[0041] (4) In the technical solution of the present invention, the cabbage extract is rich in flavonoids and anthocyanins, which can stimulate the formation of new blood vessels, ensure better tissue nutrition, promote the rapid recovery of damaged tissues, and have a high wound repair ability; the polysaccharide extract can stimulate cell growth, has a high medicinal value for tissue regeneration and wound repair, and has a good anti-inflammatory effect.

[0042] (5) In the technical scheme of the present invention, the loaded lipid nanoparticles, cabbage extract, and polysaccharide extract are compounded as wound repair drugs and added to the hydrogel as wound repair agents, which can effectively improve the wound repair ability; the complex is mixed with the chitosan solution, and the sulfate groups contained in the sodium glycerophosphate can electrostatically interact with the amino groups of the chitosan to gelate and form a cross-linked network structure hydrogel, and the complex is filled into the chitosan cross-linked network structure during the gelation process to form a wound repair exosome hydrogel rich in NAMPT. The hydrogel, as a multifunctional material of natural tissue, is used as a delivery carrier of the complex, and has the ability to effectively control the release of the complex, thereby preventing the plant extract, polysaccharide extract, and exosomes in the complex from being quickly discharged from the blood circulation, thereby affecting the wound repair effect. DETAILED DESCRIPTION

[0043] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The raw materials used in the examples of the present invention are as follows, and all reagents used are of analytical grade.

[0045] The molecular weight of chitosan is 0.8×10 6 , Tianjin Xiensi Biochemical Technology Co., Ltd.

[0046] Mesenchymal stem cells and primary mesenchymal stem cell serum-free culture system were purchased from Shanghai Saibaikang Company.

[0047] NAMPT was purchased from Shanghai Boyer Chemical Co., Ltd.

[0048] Aloe vera gel was purchased from Guangzhou Jiuhong Pharmaceutical Technology Co., Ltd.

[0049] Example 1

[0050] A method for preparing a wound repair exosome hydrogel rich in NAMPT comprises the following preparation steps:

[0051] S1. extracting exosomes from mesenchymal stem cells to obtain mesenchymal stem cell exosomes;

[0052] S2. mixing nampt, astragaloside IV, medium chain triglyceride and soybean lecithin to obtain lipid nanoparticles;

[0053] S3. mixing the lipid nanoparticles with the mesenchymal stem cell exosomes to obtain exosomes loaded with the lipid nanoparticles;

[0054] S4. mixing the exosomes loaded with lipid nanoparticles, the cabbage extract, and the polysaccharide extract to obtain a complex, wherein the mass ratio of the exosomes loaded with lipid nanoparticles, the cabbage extract, and the polysaccharide extract is 0.5:0.2:0.1;

[0055] S5. Add 0.1 g of chitosan to 8 mL of 0.1% acetic acid solution, stir evenly to obtain a chitosan solution, mix 6 mL of the chitosan solution and 0.5 mL of 0.5 g / mL β-sodium glycerophosphate solution, stir evenly, add 0.05 g of 0.4 mol / L sodium bicarbonate aqueous solution and 0.06 g of the complex, stir at 36°C for 5 min, and obtain a wound-repairing exosome hydrogel rich in nampt.

[0056] Exosomes loaded with lipid nanoparticles are specifically prepared by the following steps:

[0057] A1. The mesenchymal stem cells were cultured with a serum-free culture system for primary mesenchymal stem cells. When the cells grew to a fusion rate of 80%, the cells were subcultured. 12 mL of the culture medium of the mesenchymal stem cells cultured to the third generation was placed in a centrifuge tube, and the cell supernatant was collected by centrifugation. The cell supernatant was filtered with a 0.2 μm filter membrane, and then centrifuged at 4°C and 100,000×g for 90 min to collect the exosome precipitate. Then 0.05 mL of phosphate buffer solution was added to obtain the mesenchymal stem cell exosomes, which were stored at -70°C. Specifically, the centrifugation temperature for collecting the cell supernatant was 3°C, 300×g for 8 min, 2000×g for 15 min, and 10000×g for 25 min. The culture conditions were 36°C, 4% carbon dioxide, and saturated humidity.

[0058] A2. Add 0.03 g of astragaloside IV to 8 mL of anhydrous ethanol, stir evenly, remove the ethanol by rotary evaporation at 80 ° C, add 3 mL of 0.3% polyoxyethylene stearate solution and 0.02 g nampt, and perform ultrasound at 180 W for 5 seconds to obtain a colloid;

[0059] A3. 0.5 g of medium-chain triglyceride and 2 g of soybean lecithin were added to 15 mL of deionized water, stirred evenly, 0.2 g of colloid was added, stirred at 500 rpm for 25 min, and freeze-dried at -20 ° C for 2 h to obtain lipid nanoparticles;

[0060] A4. Mix 0.3 g of lipid nanoparticles with 8 mL of mesenchymal stem cell exosomes, stir at 36°C for 1 h, add 0.01 mL of 0.9% sodium chloride solution, and filter through a 100 KDa ultrafiltration tube to obtain exosomes loaded with lipid nanoparticles.

[0061] The cabbage extract is specifically prepared by the following steps:

[0062] The cabbage was washed with deionized water to remove impurities, dried in an oven at 70°C for 10 minutes, and crushed in a grinder. 0.3 g of the crushed cabbage was added to 8 mL of 75% ethanol aqueous solution, and ultrasonically treated for 25 minutes. The supernatant was filtered and collected, and vacuum concentrated to obtain a cabbage extract.

[0063] The polysaccharide extract is specifically prepared by the following steps:

[0064] Add 0.5 g of freeze-dried aloe vera gel to 80 mL of deionized water, stir evenly, ultrasonically treat at 25°C, 60 kHz, 550 W for 20 min, centrifuge at 4°C, 5000×g for 30 min, collect the supernatant, add 8 mL of the supernatant to 25 mL of anhydrous ethanol, let stand for 10 min, collect the precipitate, and freeze-dry at -20°C for 10 min to obtain a polysaccharide extract.

[0065] Example 2

[0066] A method for preparing a wound repair exosome hydrogel rich in NAMPT comprises the following preparation steps:

[0067] S1. extracting exosomes from mesenchymal stem cells to obtain mesenchymal stem cell exosomes;

[0068] S2. mixing nampt, astragaloside IV, medium chain triglyceride and soybean lecithin to obtain lipid nanoparticles;

[0069] S3. mixing the lipid nanoparticles with the mesenchymal stem cell exosomes to obtain exosomes loaded with the lipid nanoparticles;

[0070] S4. mixing the exosomes loaded with lipid nanoparticles, the cabbage extract, and the polysaccharide extract to obtain a composite, wherein the mass ratio of the exosomes loaded with lipid nanoparticles, the cabbage extract, and the polysaccharide extract is 0.7:0.3:0.2;

[0071] S5. Add 0.2 g of chitosan to 10 mL of 0.15% acetic acid solution, stir evenly to obtain a chitosan solution, mix 7 mL of the chitosan solution and 1 mL of 1 g / mL β-sodium glycerophosphate solution, stir evenly, add 0.05 g of 0.5 mol / L sodium bicarbonate aqueous solution and 0.08 g of the complex, stir at 37°C for 8 min, and obtain a wound-repairing exosome hydrogel rich in nampt.

[0072] Exosomes loaded with lipid nanoparticles are specifically prepared by the following steps:

[0073] A1. The mesenchymal stem cells were cultured with a serum-free culture system for primary mesenchymal stem cells. When the cells grew to a fusion rate of 80.5%, the cells were subcultured. 12 mL of the culture medium of the mesenchymal stem cells cultured to the fourth generation was placed in a centrifuge tube, and the cell supernatant was collected by centrifugation. The cell supernatant was filtered with a 0.22 μm filter membrane, and then centrifuged at 4°C and 100,000×g for 90 min to collect the exosome precipitate. 0.05 mL of phosphate buffer solution was added to obtain the mesenchymal stem cell exosomes, which were stored at -80°C. Specifically, the centrifugation temperature for collecting the cell supernatant was 4°C, 300×g for 10 min, 2000×g for 20 min, and 10,000×g for 30 min. The culture conditions were 37°C, 5% carbon dioxide, and saturated humidity.

[0074] A2. Add 0.05 g of astragaloside IV to 10 mL of anhydrous ethanol, stir evenly, remove the ethanol by rotary evaporation at 85 ° C, add 5 mL of 0.5% polyoxyethylene stearate solution and 0.03 gnampt, and perform ultrasound at 200 W for 6 s to obtain a colloid;

[0075] A3. 1 g of medium-chain triglyceride and 3 g of soybean lecithin were added to 20 mL of deionized water, stirred evenly, 0.25 g of colloid was added, stirred at 600 rpm for 30 min, and freeze-dried at -20 ° C for 2 h to obtain lipid nanoparticles;

[0076] A4. Mix 0.4 g of lipid nanoparticles with 10 mL of mesenchymal stem cell exosomes, stir at 37°C for 1.5 h, add 0.02 mL of 1% sodium chloride solution, and filter through a 110 KDa ultrafiltration tube to obtain exosomes loaded with lipid nanoparticles.

[0077] The cabbage extract is specifically prepared by the following steps:

[0078] The cabbage was washed with deionized water to remove impurities, dried in an oven at 70°C for 10 minutes, and crushed in a grinder. 0.5 g of the crushed cabbage was added to 10 mL of 80% ethanol aqueous solution, and ultrasonically treated for 30 minutes. The supernatant was collected by filtration and concentrated in vacuo to obtain a cabbage extract.

[0079] The polysaccharide extract is specifically prepared by the following steps:

[0080] Add 1 g of freeze-dried aloe vera gel to 100 mL of deionized water, stir evenly, ultrasonically treat at 25°C, 60 kHz, 550 W for 20 min, centrifuge at 4°C, 5000×g for 30 min, collect the supernatant, add 10 mL of the supernatant to 30 mL of anhydrous ethanol, let stand for 10 min, collect the precipitate, and freeze-dry at -20°C for 10 min to obtain a polysaccharide extract.

[0081] Example 3

[0082] A method for preparing a wound repair exosome hydrogel rich in NAMPT comprises the following preparation steps:

[0083] S1. extracting exosomes from mesenchymal stem cells to obtain mesenchymal stem cell exosomes;

[0084] S2. mixing nampt, astragaloside IV, medium chain triglyceride and soybean lecithin to obtain lipid nanoparticles;

[0085] S3. mixing the lipid nanoparticles with the mesenchymal stem cell exosomes to obtain exosomes loaded with the lipid nanoparticles;

[0086] S4. mixing the exosomes loaded with lipid nanoparticles, the cabbage extract, and the polysaccharide extract to obtain a complex, wherein the mass ratio of the exosomes loaded with lipid nanoparticles, the cabbage extract, and the polysaccharide extract is 1:0.4:0.3;

[0087] S5. Add 0.3 g of chitosan to 12 mL of 0.2% acetic acid solution, stir evenly to obtain a chitosan solution, mix 8 mL of the chitosan solution and 1.5 mL of 1.5 g / mL sodium β-glycerophosphate solution, stir evenly, add 0.05 g of 0.6 mol / L sodium bicarbonate aqueous solution and 0.1 g of the complex, stir at 38°C for 10 min, and obtain a wound-repairing exosome hydrogel rich in nampt.

[0088] Exosomes loaded with lipid nanoparticles are specifically prepared by the following steps:

[0089] A1. The mesenchymal stem cells were cultured with a serum-free culture system for primary mesenchymal stem cells. When the cells grew to a fusion rate of 80-81%, the cells were subcultured. 12 mL of the culture medium of the mesenchymal stem cells cultured to the fifth generation was placed in a centrifuge tube, and the cell supernatant was collected by centrifugation. The cell supernatant was filtered with a 0.23 μm filter membrane, and then centrifuged at 4°C and 100,000×g for 90 min to collect the exosome precipitate. 0.05 mL of phosphate buffer solution was added to obtain the mesenchymal stem cell exosomes, which were stored at -90°C. The specific centrifugation conditions for collecting the cell supernatant were: the centrifugation temperature was 5°C, 300×g for 12 min, 2000×g for 25 min, and 10000×g for 35 min. The specific culture conditions were: 37°C, 5% carbon dioxide, and saturated humidity.

[0090] A2. Add 0.07 g of astragaloside IV to 12 mL of anhydrous ethanol, stir evenly, remove the ethanol by rotary evaporation at 90 ° C, add 7 mL of 0.7% polyoxyethylene stearate solution and 0.04 g nampt, and perform ultrasound at 220 W for 7 seconds to obtain a colloid;

[0091] A3. 1.5 g of medium-chain triglyceride and 4 g of soybean lecithin were added to 25 mL of deionized water, stirred evenly, 0.3 g of colloid was added, stirred at 700 rpm for 35 min, and freeze-dried at -20 ° C for 2 h to obtain lipid nanoparticles;

[0092] A4. Mix 0.5 g of lipid nanoparticles with 12 mL of mesenchymal stem cell exosomes, stir at 38°C for 2 h, add 0.03 mL of 1.1% sodium chloride solution, and filter through a 120 KDa ultrafiltration tube to obtain exosomes loaded with lipid nanoparticles.

[0093] The cabbage extract is specifically prepared by the following steps:

[0094] The cabbage was washed with deionized water to remove impurities, dried in an oven at 70°C for 10 minutes, and crushed in a grinder. 0.7 g of the crushed cabbage was added to 12 mL of 85% ethanol aqueous solution, and ultrasonically treated for 35 minutes. The supernatant was filtered and collected, and vacuum concentrated to obtain a cabbage extract.

[0095] The polysaccharide extract is specifically prepared by the following steps:

[0096] Add 1.5 g of freeze-dried aloe vera gel to 100 mL of deionized water, stir evenly, ultrasonically treat at 25°C, 60 kHz, 550 W for 20 min, centrifuge at 4°C, 5000×g for 30 min, collect the supernatant, add 12 mL of the supernatant to 35 mL of anhydrous ethanol, let stand for 10 min, collect the precipitate, and freeze-dry at -20°C for 10 min to obtain a polysaccharide extract.

[0097] Comparative Example 1

[0098] A method for preparing a wound repair exosome hydrogel rich in NAMPT comprises the following preparation steps:

[0099] S1. extracting exosomes from mesenchymal stem cells to obtain mesenchymal stem cell exosomes;

[0100] S2. mixing nampt with mesenchymal stem cell exosomes to obtain nampt-rich exosomes;

[0101] S4. mixing the nampt-rich exosomes, the cabbage extract, and the polysaccharide extract to obtain a composite, wherein the mass ratio of the nampt-rich exosomes, the cabbage extract, and the polysaccharide extract is 1:0.4:0.3;

[0102] S5. Add 0.3 g of chitosan to 12 mL of 0.2% acetic acid solution, stir evenly to obtain a chitosan solution, mix 8 mL of the chitosan solution and 1.5 mL of 1.5 g / mL sodium β-glycerophosphate solution, stir evenly, add 0.05 g of 0.6 mol / L sodium bicarbonate aqueous solution and 0.1 g of the complex, stir at 38°C for 10 min, and obtain a wound-repairing exosome hydrogel rich in nampt.

[0103] Exosomes enriched with nampt are prepared by the following steps:

[0104] A1. The mesenchymal stem cells were cultured with a serum-free culture system for primary mesenchymal stem cells. When the cells grew to a fusion rate of 81%, the cells were subcultured. 12 mL of the mesenchymal stem cell culture medium cultured to the third generation was placed in a centrifuge tube, and the cell supernatant was collected by centrifugation. The cell supernatant was filtered with a 0.23 μm filter membrane, and then centrifuged at 4°C and 100,000×g for 90 min to collect the exosome precipitate. 0.05 mL of phosphate buffer solution was added to obtain the mesenchymal stem cell exosomes, which were stored at -90°C. Specifically, the cell supernatant was collected by centrifugation as follows: the centrifugation temperature was 5°C, 300×g for 12 min, 2000×g for 25 min, and 10000×g for 35 min. The culture conditions were as follows: 37°C, 5% carbon dioxide, and saturated humidity.

[0105] A2. Mix 0.5 g of nampt with 12 mL of mesenchymal stem cell exosomes, stir at 38°C for 2 h, add 0.03 mL of 1.1% sodium chloride solution, and filter through a 120 KDa ultrafiltration tube to obtain exosomes loaded with lipid nanoparticles.

[0106] The cabbage extract is specifically prepared by the following steps:

[0107] The cabbage was washed with deionized water to remove impurities, dried in an oven at 70°C for 10 minutes, and crushed in a grinder. 0.7 g of the crushed cabbage was added to 12 mL of 85% ethanol aqueous solution, and ultrasonically treated for 35 minutes. The supernatant was filtered and collected, and vacuum concentrated to obtain a cabbage extract.

[0108] The polysaccharide extract is specifically prepared by the following steps:

[0109] Add 1.5 g of freeze-dried aloe vera gel to 100 mL of deionized water, stir evenly, ultrasonically treat at 25°C, 60 kHz, 550 W for 20 min, centrifuge at 4°C, 5000×g for 30 min, collect the supernatant, add 12 mL of the supernatant to 35 mL of anhydrous ethanol, let stand for 10 min, collect the precipitate, and freeze-dry at -20°C for 10 min to obtain a polysaccharide extract.

[0110] Comparative Example 2

[0111] A method for preparing a wound repair exosome hydrogel rich in NAMPT comprises the following preparation steps:

[0112] S1. extracting exosomes from mesenchymal stem cells to obtain mesenchymal stem cell exosomes;

[0113] S2. mixing nampt, medium chain triglyceride and soybean lecithin to obtain lipid nanoparticles;

[0114] S3. mixing the lipid nanoparticles with the mesenchymal stem cell exosomes to obtain exosomes loaded with the lipid nanoparticles;

[0115] S4. mixing the exosomes loaded with lipid nanoparticles, the cabbage extract, and the polysaccharide extract to obtain a complex, wherein the mass ratio of the exosomes loaded with lipid nanoparticles, the cabbage extract, and the polysaccharide extract is 1:0.4:0.3;

[0116] S5. Add 0.3 g of chitosan to 12 mL of 0.2% acetic acid solution, stir evenly to obtain a chitosan solution, mix 8 mL of the chitosan solution and 1.5 mL of 1.5 g / mL sodium β-glycerophosphate solution, stir evenly, add 0.05 g of 0.6 mol / L sodium bicarbonate aqueous solution and 0.1 g of the complex, stir at 38°C for 10 min, and obtain a wound-repairing exosome hydrogel rich in nampt.

[0117] Exosomes loaded with lipid nanoparticles are specifically prepared by the following steps:

[0118] A1. The mesenchymal stem cells were cultured with a serum-free culture system for primary mesenchymal stem cells. When the cells grew to a fusion rate of 81%, the cells were subcultured. 12 mL of the mesenchymal stem cell culture medium cultured to the third generation was placed in a centrifuge tube, and the cell supernatant was collected by centrifugation. The cell supernatant was filtered with a 0.23 μm filter membrane, and then centrifuged at 4°C and 100,000×g for 90 min to collect the exosome precipitate. 0.05 mL of phosphate buffer solution was added to obtain the mesenchymal stem cell exosomes, which were stored at -90°C. Specifically, the cell supernatant was collected by centrifugation as follows: the centrifugation temperature was 5°C, 300×g for 12 min, 2000×g for 25 min, and 10000×g for 35 min. The culture conditions were as follows: 37°C, 5% carbon dioxide, and saturated humidity.

[0119] A2. 1.5 g of medium-chain triglycerides and 4 g of soybean lecithin were added to 25 mL of deionized water, stirred evenly, 0.3 g of nampt was added, stirred at 700 rpm for 35 min, and freeze-dried at -20 ° C for 2 h to obtain lipid nanoparticles;

[0120] A3. Mix 0.5 g of lipid nanoparticles with 12 mL of mesenchymal stem cell exosomes, stir at 38°C for 2 h, add 0.03 mL of 1.1% sodium chloride solution, and filter through a 120 KDa ultrafiltration tube to obtain exosomes loaded with lipid nanoparticles.

[0121] The cabbage extract is specifically prepared by the following steps:

[0122] The cabbage was washed with deionized water to remove impurities, dried in an oven at 70°C for 10 minutes, and crushed in a grinder. 0.7 g of the crushed cabbage was added to 12 mL of 85% ethanol aqueous solution, and ultrasonically treated for 35 minutes. The supernatant was filtered and collected, and vacuum concentrated to obtain a cabbage extract.

[0123] The polysaccharide extract is specifically prepared by the following steps:

[0124] Add 1.5 g of freeze-dried aloe vera gel to 100 mL of deionized water, stir evenly, ultrasonically treat at 25°C, 60 kHz, 550 W for 20 min, centrifuge at 4°C, 5000×g for 30 min, collect the supernatant, add 12 mL of the supernatant to 35 mL of anhydrous ethanol, let stand for 10 min, collect the precipitate, and freeze-dry at -20°C for 10 min to obtain a polysaccharide extract.

[0125] Comparative Example 3

[0126] A method for preparing a wound repair exosome hydrogel rich in NAMPT comprises the following preparation steps:

[0127] S1. extracting exosomes from mesenchymal stem cells to obtain mesenchymal stem cell exosomes;

[0128] S2. mixing nampt, astragaloside IV, medium chain triglyceride and soybean lecithin to obtain lipid nanoparticles;

[0129] S3. mixing the lipid nanoparticles with the mesenchymal stem cell exosomes to obtain exosomes loaded with the lipid nanoparticles;

[0130] S4. mixing the exosomes loaded with lipid nanoparticles and the polysaccharide extract to obtain a complex, wherein the mass ratio of the exosomes loaded with lipid nanoparticles to the polysaccharide extract is 1:0.3;

[0131] S5. Add 0.3 g of chitosan to 12 mL of 0.2% acetic acid solution, stir evenly to obtain a chitosan solution, mix 8 mL of the chitosan solution and 1.5 mL of 1.5 g / mL sodium β-glycerophosphate solution, stir evenly, add 0.05 g of 0.6 mol / L sodium bicarbonate aqueous solution and 0.1 g of the complex, stir at 38°C for 10 min, and obtain a wound-repairing exosome hydrogel rich in nampt.

[0132] Exosomes loaded with lipid nanoparticles are specifically prepared by the following steps:

[0133] A1. The mesenchymal stem cells were cultured with a serum-free culture system for primary mesenchymal stem cells. When the cells grew to a fusion rate of 81%, the cells were subcultured. 12 mL of the mesenchymal stem cell culture medium cultured to the third generation was placed in a centrifuge tube, and the cell supernatant was collected by centrifugation. The cell supernatant was filtered with a 0.23 μm filter membrane, and then centrifuged at 4°C and 100,000×g for 90 min to collect the exosome precipitate. 0.05 mL of phosphate buffer solution was added to obtain the mesenchymal stem cell exosomes, which were stored at -90°C. Specifically, the cell supernatant was collected by centrifugation as follows: the centrifugation temperature was 5°C, 300×g for 12 min, 2000×g for 25 min, and 10000×g for 35 min. The culture conditions were as follows: 37°C, 5% carbon dioxide, and saturated humidity.

[0134] A2. Add 0.07 g of astragaloside IV to 12 mL of anhydrous ethanol, stir evenly, remove the ethanol by rotary evaporation at 90 ° C, add 7 mL of 0.7% polyoxyethylene stearate solution and 0.04 g nampt, and perform ultrasound at 220 W for 7 seconds to obtain a colloid;

[0135] A3. 1.5 g of medium-chain triglyceride and 4 g of soybean lecithin were added to 25 mL of deionized water, stirred evenly, 0.3 g of colloid was added, stirred at 700 rpm for 35 min, and freeze-dried at -20 ° C for 2 h to obtain lipid nanoparticles;

[0136] A4. Mix 0.5 g of lipid nanoparticles with 12 mL of mesenchymal stem cell exosomes, stir at 38°C for 2 h, add 0.03 mL of 1.1% sodium chloride solution, and filter through a 120 KDa ultrafiltration tube to obtain exosomes loaded with lipid nanoparticles.

[0137] The polysaccharide extract is specifically prepared by the following steps:

[0138] Add 1.5 g of freeze-dried aloe vera gel to 100 mL of deionized water, stir evenly, ultrasonically treat at 25°C, 60 kHz, 550 W for 20 min, centrifuge at 4°C, 5000×g for 30 min, collect the supernatant, add 12 mL of the supernatant to 35 mL of anhydrous ethanol, let stand for 10 min, collect the precipitate, and freeze-dry at -20°C for 10 min to obtain a polysaccharide extract.

[0139] Comparative Example 4

[0140] A method for preparing a wound repair exosome hydrogel rich in NAMPT comprises the following preparation steps:

[0141] S1. extracting exosomes from mesenchymal stem cells to obtain mesenchymal stem cell exosomes;

[0142] S2. mixing nampt, astragaloside IV, medium chain triglyceride and soybean lecithin to obtain lipid nanoparticles;

[0143] S3. mixing the lipid nanoparticles with the mesenchymal stem cell exosomes to obtain exosomes loaded with the lipid nanoparticles;

[0144] S4. mixing the exosomes loaded with lipid nanoparticles and the cabbage extract to obtain a composite, wherein the mass ratio of the exosomes loaded with lipid nanoparticles to the cabbage extract is 1:0.4;

[0145] S5. Add 0.3 g of chitosan to 12 mL of 0.2% acetic acid solution, stir evenly to obtain a chitosan solution, mix 8 mL of the chitosan solution and 1.5 mL of 1.5 g / mL sodium β-glycerophosphate solution, stir evenly, add 0.05 g of 0.6 mol / L sodium bicarbonate aqueous solution and 0.1 g of the complex, stir at 38°C for 10 min, and obtain a wound-repairing exosome hydrogel rich in nampt.

[0146] Exosomes loaded with lipid nanoparticles are specifically prepared by the following steps:

[0147] A1. The mesenchymal stem cells were cultured with a serum-free culture system for primary mesenchymal stem cells. When the cells grew to a fusion rate of 81%, the cells were subcultured. 12 mL of the mesenchymal stem cell culture medium cultured to the third generation was placed in a centrifuge tube, and the cell supernatant was collected by centrifugation. The cell supernatant was filtered with a 0.23 μm filter membrane, and then centrifuged at 4°C and 100,000×g for 90 min to collect the exosome precipitate. 0.05 mL of phosphate buffer solution was added to obtain the mesenchymal stem cell exosomes, which were stored at -90°C. Specifically, the cell supernatant was collected by centrifugation as follows: the centrifugation temperature was 5°C, 300×g for 12 min, 2000×g for 25 min, and 10000×g for 35 min. The culture conditions were as follows: 37°C, 5% carbon dioxide, and saturated humidity.

[0148] A2. Add 0.07 g of astragaloside IV to 12 mL of anhydrous ethanol, stir evenly, remove the ethanol by rotary evaporation at 90 ° C, add 7 mL of 0.7% polyoxyethylene stearate solution and 0.04 g nampt, and perform ultrasound at 220 W for 7 seconds to obtain a colloid;

[0149] A3. 1.5 g of medium-chain triglyceride and 4 g of soybean lecithin were added to 25 mL of deionized water, stirred evenly, 0.3 g of colloid was added, stirred at 700 rpm for 35 min, and freeze-dried at -20 ° C for 2 h to obtain lipid nanoparticles;

[0150] A4. Mix 0.5 g of lipid nanoparticles with 12 mL of mesenchymal stem cell exosomes, stir at 38°C for 2 h, add 0.03 mL of 1.1% sodium chloride solution, and filter through a 120 KDa ultrafiltration tube to obtain exosomes loaded with lipid nanoparticles.

[0151] The cabbage extract is specifically prepared by the following steps:

[0152] The cabbage was washed with deionized water to remove impurities, dried in an oven at 70°C for 10 minutes, and crushed in a grinder. 0.7 g of the crushed cabbage was added to 12 mL of an 85% ethanol aqueous solution, and ultrasonically treated for 35 minutes. The supernatant was filtered and collected, and concentrated in vacuo to obtain a cabbage extract.

[0153] Comparative Example 5

[0154] A method for preparing a wound repair exosome hydrogel rich in NAMPT comprises the following preparation steps:

[0155] S1. extracting exosomes from mesenchymal stem cells to obtain mesenchymal stem cell exosomes;

[0156] S5. Add 0.3 g of chitosan to 12 mL of 0.2% acetic acid solution, stir evenly to obtain a chitosan solution, mix 8 mL of the chitosan solution and 1.5 mL of 1.5 g / mL sodium β-glycerophosphate solution, stir evenly, add 0.05 g of 0.6 mol / L sodium bicarbonate aqueous solution and 0.1 g of mesenchymal stem cell exosomes, stir at 38°C for 10 min, and obtain a wound repair exosome hydrogel rich in nampt.

[0157] Mesenchymal stem cell exosomes are specifically prepared by the following steps:

[0158] Mesenchymal stem cells were cultured using a primary mesenchymal stem cell serum-free culture system, and subcultured when the cells grew to a fusion rate of 81%. 12 mL of mesenchymal stem cell culture fluid cultured to the third generation was placed in a centrifuge tube, and the cell supernatant was collected by centrifugation. The cell supernatant was filtered with a 0.23 μm filter membrane, and then centrifuged at 4°C and 100,000×g for 90 min to collect the exosome precipitate, and then 0.05 mL of phosphate buffer solution was added to obtain mesenchymal stem cell exosomes, which were stored at -90°C; wherein, the centrifugal collection of the cell supernatant was specifically as follows: the centrifugation temperature was 5°C, 300×g for 12 min; 2000×g for 25 min; 10000×g for 35 min; the culture conditions were specifically as follows: 37°C, 5% carbon dioxide, and saturated humidity.

[0159] The performance of the wound repair exosome hydrogels rich in NAMPT prepared in Examples 1-3 and Comparative Examples 1-5 was tested.

[0160] Mice weighing 30 g were anesthetized intraperitoneally with 35 mg / kg sodium pentobarbital solution. When the mice were unconscious and had no obvious reaction, they were fixed on the operating table in a prone position. The hair on the back of the mice was removed with a hair scraper. The back skin was wiped with 75% alcohol. Then, a 2.25 cm-long cut was made on the back of the mice with small scissors and tweezers. 2 Full-thickness skin defect; 0.5 mL of the nampt-rich wound-repairing exosome hydrogel prepared above was injected into the skin defect of the mouse and the mouse was returned to the cage. Food and water were adequately supplied during the experiment. During the experiment, the wound area on the nth day (n=3, 7, 14) was calculated using ImageJ software, and the wound healing rate on the 14th day was calculated as (initial wound area-wound area on the 14th day) / initial wound area×100%.

[0161] After 15 days, the healed skin tissue was taken and used to prepare frozen sections to observe the wound healing effect of the mouse skin wound under an optical microscope, as shown in Table 1 below.

[0162] Table 1 Performance test of hydrogels prepared in Examples 1-3 and Comparative Examples 1-5

[0163]

[0164] It can be seen from the data in Table 1 that the wound repair exosome hydrogels rich in nampt prepared in Examples 1-3 have good wound repair effects. In Comparative Example 1, the wound repair properties of the wound repair exosome hydrogel rich in nampt prepared by replacing lipid nanoparticles with nampt decreased, proving that the small size structure of nampt embedded in lipid nanoparticles can effectively deliver nampt to the wound site, and can protect nampt from degradation in the body environment, thereby improving the bioavailability and therapeutic effect of nampt.

[0165] In Comparative Example 2, the exosomes loaded with lipid nanoparticles prepared by replacing the colloid with NAMPT were added to the hydrogel, and its wound repair property decreased, proving that the dispersion of NAMPT in the astragaloside colloid is beneficial to improving the stability of NAMPT in the hydrogel, and astragaloside I can significantly promote the migration of keratinocytes and promote angiogenesis, thereby promoting wound repair.

[0166] In comparative example 3, the wound repairing exosome hydrogel rich in NAMPT prepared without adding cabbage extract had decreased wound repairing ability, indicating that cabbage extract is rich in flavonoids and anthocyanins, which can stimulate the formation of new blood vessels, ensure better tissue nutrition, promote the rapid recovery of damaged tissues, and has a high wound repairing ability.

[0167] In comparative example 4, the wound repairing exosome hydrogel rich in NAMPT prepared without adding polysaccharide extract had decreased wound repairing ability, which proved that the polysaccharide extract could stimulate cell growth, had high medicinal value for tissue regeneration and wound repair, and had good anti-inflammatory effect.

[0168] In Comparative Example 5, the complex was replaced with mesenchymal stem cell exosomes and added to the hydrogel, and its wound repair ability decreased, proving that the exosomes loaded with lipid nanoparticles, cabbage extract, and polysaccharide extract are combined as wound repair drugs and added to the hydrogel as wound repair agents, which can effectively improve the wound repair ability.

[0169] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0170] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A method for preparing a wound repair exosome hydrogel rich in nampt, characterized in that: The method comprises the following preparation steps: S1. extracting exosomes from mesenchymal stem cells to obtain mesenchymal stem cell exosomes; S2. mixing nampt, astragaloside IV, medium chain triglyceride and soybean lecithin to obtain lipid nanoparticles; S3. mixing the lipid nanoparticles with the mesenchymal stem cell exosomes to obtain exosomes loaded with the lipid nanoparticles; S4. mixing the exosomes loaded with lipid nanoparticles, the cabbage extract, and the polysaccharide extract to obtain a complex; S5. Mix the complex, chitosan solution, and sodium β-glycerophosphate solution, and stir at 36-38° C. for 5-10 minutes to obtain a wound-repairing exosome hydrogel rich in NAMPT.

2. The method for preparing a wound repair exosome hydrogel rich in NAMPT according to claim 1, characterized in that: The exosomes loaded with lipid nanoparticles are specifically prepared by the following steps: A1. Cultivate mesenchymal stem cells using a primary mesenchymal stem cell serum-free culture system. When the cells grow to a fusion rate of 80-81%, subculture them. Take the culture medium of mesenchymal stem cells cultured to the 3rd to 5th generation and place it in a centrifuge tube. Centrifuge to collect the cell supernatant. After filtering the cell supernatant with a 0.2-0.23 μm filter membrane, centrifuge to collect the exosome precipitate, and then add a phosphate buffer solution. The obtained mesenchymal stem cell exosomes are stored at -(70-90)°C; A2. Astragaloside IV was added to anhydrous ethanol, stirred evenly, and after removing the ethanol by rotary evaporation at 80-90°C, a 0.3-0.7% polyoxyethylene stearate solution and nampt were added, and ultrasonicated at 180-220W for 5-7s to obtain a colloid; A3. Add medium chain triglycerides and soybean lecithin to deionized water, stir evenly, add colloid, stir at 500-700 rpm for 25-35 min, and freeze-dry to obtain lipid nanoparticles; A4. Mix the lipid nanoparticles with the mesenchymal stem cell exosomes, stir at 36-38°C for 1-2h, add a sodium chloride solution with a mass fraction of 0.9-1.1%, and filter through a 100-120KDa ultrafiltration tube to obtain exosomes loaded with lipid nanoparticles.

3. The method for preparing a wound repair exosome hydrogel rich in NAMPT according to claim 2, characterized in that: In step A1, the culture conditions are specifically: 36-38°C, containing 4-6% carbon dioxide, and saturated humidity; the centrifugal collection of cell supernatant is specifically: centrifugal temperature is 3-5°C, 300×g centrifugation for 8-12min; 2000×g centrifugation for 15-25min; 10000×g centrifugation for 25-35min.

4. The method for preparing a wound repair exosome hydrogel rich in NAMPT according to claim 2, characterized in that: In step A2, the amount ratio of astragaloside IV, anhydrous ethanol, polyoxyethylene stearate solution, and nampt is (0.03-0.07) g: (8-12) mL: (3-7) mL: (0.02-0.04) g.

5. The method for preparing a wound repair exosome hydrogel rich in NAMPT according to claim 2, characterized in that: In step A3, the ratio of medium chain triglyceride, soybean lecithin, deionized water and colloid is (0.5-1.5) g: (2-4) g: (15-25) mL: (0.2-0.3) g.

6. The method for preparing a wound repair exosome hydrogel rich in NAMPT according to claim 2, characterized in that: In step A4, the ratio of the lipid nanoparticles, mesenchymal stem cell exosomes, and sodium chloride solution is (0.3-0.5) g: (8-12) mL: (0.01-0.03) mL.

7. The method for preparing a wound repair exosome hydrogel rich in NAMPT according to claim 1, characterized in that: The cabbage extract is specifically prepared by the following steps: The cabbage is washed with deionized water to remove impurities, dried, and then crushed in a crusher. The crushed cabbage is added to an ethanol aqueous solution with a mass fraction of 75-85%, ultrasonically treated for 25-35 minutes, and the supernatant is filtered and collected. The cabbage extract is obtained by vacuum concentration.

8. The method for preparing a wound repair exosome hydrogel rich in NAMPT according to claim 1, characterized in that: The polysaccharide extract is specifically prepared by the following steps: The freeze-dried aloe vera gel is added to deionized water, stirred evenly, and after ultrasonic treatment, the supernatant is collected by centrifugation, and the supernatant is added to anhydrous ethanol, allowed to stand, and the precipitate is collected and freeze-dried to obtain a polysaccharide extract.

9. The method for preparing a wound repair exosome hydrogel rich in NAMPT according to claim 1, characterized in that: The mass ratio of the exosomes loaded with lipid nanoparticles, the cabbage extract, and the polysaccharide extract is (0.5-1):(0.2-0.4):(0.1-0.3); the dosage ratio of the complex, the chitosan solution, and the β-sodium glycerophosphate solution is (0.06-0.1) g:(6-8) mL:(0.5-1.5) mL.

10. A wound-repairing exosome hydrogel rich in NAMPT obtained by the preparation method according to any one of claims 1 to 9.

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