Photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair and preparation method and application thereof

Abstract

The application provides a photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair, which comprises a hydrogel carrier and AIE vesicles loaded in the hydrogel carrier; the AIE vesicles are AIE molecules wrapped with artificial stem cell vesicles on the outer surface; the mass ratio of the AIE molecules to the artificial stem cell vesicles ranges from 1:3 to 50, and the maximum final concentration of the AIE molecules in the AIE vesicles is not more than 400 micromoles per liter. The hydrogel not only has excellent anti-infection, antibacterial, repair-promoting regulation functions and good biological safety, but also has good stability and long-acting property. In addition, the hydrogel is simple to prepare and low in cost, has good universality, and has good practical popularization significance in the treatment of various infections.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydrogel materials, and more particularly relates to a photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair and a preparation method and application thereof. BACKGROUND

[0002] Severe skin damage such as scalds and burns face the double problems of repeated infections and difficult healing after healing due to damage to the dermis layer and complications such as repeated infections, which makes it difficult for the epidermal structure to recover and may also result in contracture deformity and other consequences, aggravating the physical and mental burden of patients. Traditional wound repair methods mainly include drug therapy, use of dressings, pressure therapy, skin transplantation, etc., but it is still difficult to achieve complete repair, and large-area deep infection is prone to complications such as sepsis, prolonging the treatment process.

[0003] Current new repair-promoting biological therapies such as platelet-rich plasma therapy, extracellular matrix therapy, stem cell therapy, and stem cell extracellular vesicle therapy have the advantage of being difficult to replace and significant therapeutic effect because they can provide comprehensive pro-healing biological therapy components of autologous origin to the wound. Among them, stem cells can secrete extracellular vesicles containing protein and RNA signaling molecules through paracrine, and such extracellular vesicles have been reported to have low immune response and the ability to home target, activate certain signaling pathways, and promote the up-regulation of expression of various cell growth factors, thereby achieving the synchronous proliferation and repair of various cells. Due to their small size, they have better tissue penetration, stability, and safety than cells, making it easy to deliver small molecule drugs, proteins, and nucleic acids. However, there are still problems such as high price, lack of anti-infection function, and limited action time. Tang Benzhong et al. once reported that using AIE materials to modify tumor extracellular vesicles can target and photodynamically treat tumor cells (Angew. Chem. Int. Ed. 2020, 59, 13836-13843), but no photodynamic therapy vesicles suitable for wound antibiosis and repair promotion have been reported.

[0004] Extracellular vesicles used in wound surface are usually injected clinically, but the effect time is short and easy to fail. Hydrogel is a kind of polymer sustained-release material with three-dimensional network structure, which is widely used in medical and tissue engineering fields as cell scaffold, drug delivery system, soft tissue substitute and wound dressing, etc. The good biocompatibility and degradable characteristics of hydrogel can form a drug depot at the lesion site to achieve local controlled release of drugs, thereby improving the effective accumulation of drugs at the lesion site and achieving the purpose of treatment. However, in order to load vesicles into the gel, it is necessary to ensure that the preparation process of the gel does not damage the components of the vesicles. Common temperature-sensitive hydrogels such as PF-127 and its complexes (Nanoscale, 2021, 13, 14866-14878) have less selectivity and cannot achieve targeted controlled release according to the microenvironment of the wound surface. Other controllable hydrogels mostly need light, heating or catalysts to assist curing, which may damage the effective components in the vesicles. In addition, although most laboratories have developed a variety of separation and extraction technologies such as size exclusion chromatography column, microfluidic and immune capture, the cost of obtaining extracellular vesicles is still high and the process is complex. Therefore, how to provide a hydrogel material combined with extracellular vesicles with excellent functions has become a technical problem to be solved at present. SUMMARY

[0005] In view of the above existing technical problems, the primary purpose of the present application is to provide a photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair, which not only has excellent anti-infection, antibacterial, repair-promoting regulation functions, good biological safety and stability, but also has a mild and rapid preparation process, ensuring the stability and long-acting of the loaded vesicles.

[0006] The second purpose of the present application is to provide a preparation method of the above-mentioned photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair.

[0007] The third purpose of the present application is to provide the application of the above-mentioned photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair in the preparation of wound repair materials.

[0008] A photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair, comprising a hydrogel carrier and AIE vesicles loaded in the hydrogel carrier; the AIE vesicles are AIE molecules wrapped with artificial stem cell vesicles on the outer surface; the mass ratio of the AIE molecules to the artificial stem cell vesicles ranges from 1:3 to 50, and the maximum final concentration of AIE molecules in the AIE vesicles does not exceed 400 μmol / L.

[0009] The application provides an artificial stem cell vesicle hydrogel with a function of promoting wound repair, which is prepared by the following steps: firstly, using an artificial extrusion preparation technology, stem cells are lysed by a hypotonic solution after subculture, and then cell components and phospholipid membranes separated are extruded by a liposome extruder to obtain artificial stem cell vesicles, so that the multiple healing components of the original stem cells are retained, the operation is simple, the yield is high, and the artificial stem cell vesicles are convenient for large-scale preparation, and the problems of safety and controllability of traditional stem cell treatment are overcome. Further, the artificial stem cell vesicles are combined with specific AIE molecules (light-driven antibacterial aggregation-induced emission material (Aggregation-Induced Emission)) to obtain AIE vesicles. In the process, the inventor finds that the maximum final concentration of AIE in the AIE vesicles needs to be not more than 400 μmol / L, and the concentration is the limit of loading; if the concentration continues to increase, AIE cannot be well dispersed, and then solid precipitates are separated out, which affects the preparation of AIE vesicles and subsequent combination with hydrogels. Finally, the AIE vesicles are loaded with a long-acting sustained-release hydrogel carrier to solve the problems of insufficient anti-infection ability, limited stability of the vesicles directly acting on the body surface, short half-life and the like.

[0010] Preferably, the structure formula of the AIE molecule is as follows:

[0011]

[0012] wherein R - is an anion for balancing charge, and is selected from one of Cl - , Br - , I - and PF6 - . The AIE molecule has outstanding anti-infection ability and good biocompatibility; in addition, the AIE molecule has excellent water medium dispersion capacity and can be better combined with the vesicles.

[0013] Preferably, the hydrogel carrier is prepared by click chemistry reaction of an amine group-containing or thiol group-containing natural water-soluble polymer compound and an ester alkyne group-containing water-soluble compound according to a functional group ratio of 1-10:10-1. The hydrogel carrier is obtained by click reaction between the activated ester alkyne group and the amine group-containing or thiol group-containing polymer compound, the conditions are milder, and the process is simpler, without the need of heating, light irradiation or external catalyst catalysis, so that additional steps and residues of toxic catalysts are avoided, and the amino acrylate bond formed has acid responsiveness, so as to give the hydrogel controllable release characteristics.

[0014] Further preferably, the amine group-containing or thiol group-containing natural water-soluble polymer compound is selected from one or more of chitosan and its derivatives and sodium carboxymethyl cellulose.

[0015] Preferably, the ester-containing acetylenic group-containing water-soluble compound has one or more of the following structures shown in any one of the following formula (II):

[0016]

[0017] wherein n is an integer greater than or equal to 1.

[0018] Preferably, the artificial stem cell vesicle is derived from one or more of adipose stem cells, fibroblast stem cells, and epidermal stem cells.

[0019] Preferably, the mass ratio of the AIE vesicle to the hydrogel carrier is 0.67-10:1.

[0020] Further, the present application also claims a preparation method of a photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair, comprising the following preparation steps:

[0021] S1. Obtain a membrane suspension by lysing artificial stem cells, and obtain an artificial stem cell vesicle by extruding through a liposome extruder;

[0022] S2. After co-incubation of the artificial stem cell vesicle with the AIE molecule, extrude through a liposome extruder to realize coating of the AIE molecule by the artificial stem cell vesicle, and obtain an AIE vesicle;

[0023] S3. Add an aqueous solution of the AIE vesicle or a PBS solution of the AIE vesicle to a precursor solution of the hydrogel carrier, stand still, and solidify to obtain the photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair.

[0024] Preferably, in the aqueous solution of the AIE vesicle or the PBS solution of the AIE vesicle, the concentration of the AIE vesicle ranges from 1 to 300 μg / mL (mass percentage concentration ranges from 0.1% to 30%).

[0025] Preferably, in the precursor solution of the hydrogel carrier, the mass percentage concentration of the hydrogel carrier ranges from 3% to 15%.

[0026] Preferably, the precursor solution of the hydrogel carrier is obtained by mixing an amine group-containing or thiol group-containing natural water-soluble high molecular compound and an ester-containing acetylenic group-containing water-soluble compound.

[0027] Preferably, in the step S3, the standing time is 4-24 h.

[0028] Preferably, in the step S1 and the step S2, the liposome extruder is a 100 nm-900 nm liposome extruder.

[0029] Further preferably, in the step S1, the liposome extruder is a 600-800nm liposome extruder; in the step S2, the liposome extruder is a 100-200nm liposome extruder.

[0030] In addition, the application also claims the use of the above-mentioned photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair in the preparation of wound repair materials. The hydrogel plays a role in wound repair by regulating the release of bactericidal, bacteriostatic and tissue self-repair promoting AIE vesicle components at the wound site, while isolating the wound from air exposure and reducing pathogen infection.

[0031] Compared with the prior art, the application has the following beneficial effects: the application provides a photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair; the hydrogel not only has excellent anti-infection, antibacterial, repair promoting regulation functions and good biological safety, but also has good stability and long-acting property. In addition, the hydrogel is simple to prepare and low in cost, has good universality, and has good practical popularization significance in the treatment of various infections. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is the nuclear magnetic resonance hydrogen spectrum of the AIE molecule in Example 1.

[0033] Figure 2 It is the characterization of the vesicle in Example 1, wherein, Figure 2 (a) is a transmission electron micrograph of the vesicle; Figure 2 (b) is the result of the vesicle NTA test.

[0034] Figure 3 It is the nuclear magnetic resonance hydrogen spectrum of PEG4000-DA in Example 1.

[0035] Figure 4 It is a transmission electron micrograph of the artificial stem cell vesicle hydrogel with the function of promoting wound repair in Example 1.

[0036] Figure 5 It is an antibacterial ability experiment graph of the THB vesicle in Example 1 on Staphylococcus aureus and Escherichia coli.

[0037] Figure 6 It is an antibacterial ability experiment graph of the TCB vesicle in Comparative Example 2 on Staphylococcus aureus and Escherichia coli.

[0038] Figure 7 It is the statistical result of the AIE vesicle in Example 1 and the vesicle in Comparative Example 1 promoting cell proliferation.

[0039] Figure 8Figure for scratch test of AIE vesicles in Example 1 and vesicles in Comparative Example 1.

[0040] Figure 9 Figure for acid-responsive release ability characterization of artificial stem cell vesicle hydrogel with wound repair promoting function in Example 1.

[0041] Figure 10 Figure for repair effect after scald wound of mice in each treatment group. DETAILED DESCRIPTION

[0042] The present application is further illustrated by the following description in conjunction with the drawings and examples, but the examples do not limit the present application in any form. Unless otherwise specified, the reagents, methods and devices used in the present application are conventional reagents, methods and devices in the technical field.

[0043] Example 1 Preparation of artificial stem cell vesicle hydrogel with wound repair promoting function

[0044] (1) Synthesis of AIE molecule (THB): 4-methylpyridine (5 mmol, 487 μL, commercially available) and 2-bromoethanol (5 mmol, 354 μL, commercially available) were heated at 50°C in acetonitrile for 24 h, most of the solvent was removed, and then 5-(4-(diphenylamino)phenyl)thiophene-2-carboxaldehyde (142 mg, 0.4 mmol, commercially available) was added after redissolving in ethanol, and a catalytic amount of piperidine was added. The mixture was heated to 80°C and stirred under nitrogen for 16 hours. After removing the solvent with a rotary evaporator, the product was purified with a neutral alumina column using dichloromethane / methanol (v / v = 4 / 1) as the eluent to obtain a red solid, which was THB (i.e. AIE molecule). The preparation equation of AIE molecule is shown below:

[0045]

[0046] (2) Preparation of AIE vesicles: artificial stem cell membrane suspension was obtained by lysing artificial stem cells, and artificial stem cell vesicles were obtained by extrusion through a liposome extruder. The specific preparation steps are as follows: after extracting primary adipose stem cells from rat adipose tissue and culturing in vitro, the cell precipitate was added to a hypotonic cell lysis buffer (about 100 ul of lysis buffer was added for every 5 x 10 6 cells), and the cell suspension was subjected to 20 times of regrinding with a tissue grinding pestle after the cells were fully lysed at 4°C overnight. The supernatant was obtained by centrifugation at 3500g for 5 min at 4°C, and the precipitate was removed. The cell membrane was preliminarily reconstructed by passing through a Millipore polycarbonate (PCTE) membrane with a pore size of 800 nm using a liposome extruder, and the obtained solution was collected by repeatedly extruding and sieving to remove impurities, thereby obtaining artificial stem cell vesicles;

[0047] A small amount of DMSO solution of AIE molecules obtained in step (1) is added to the artificial stem cell vesicles, and the mass ratio of AIE molecules to artificial stem cell vesicles is 1:5. After incubation for 30 minutes, the final reconstruction of the vesicles is completed by repeatedly extruding the vesicles through a Millipore polycarbonate (PCTE) membrane with a pore size of 200 nm using a liposome extruder. The obtained vesicles are purified using gradient centrifugation or a 20 kDa ultrafiltration membrane to remove components not encapsulated into the vesicle structure, and a pure AIE functionalized adipose stem cell vesicle solution (i.e., AIE vesicles or THB vesicles) is obtained; wherein the final concentration of AIE in the AIE vesicles is about 125 μmol / L.

[0048] (3) Preparation of artificial stem cell vesicle hydrogel with wound repair promoting function: PEG-4000 (10 g, 2.5 mmol, commercially available) and excess propargyl acid (1.75 g, 25 mmol, commercially available) and a catalytic amount of p-toluenesulfonic acid (0.29 g, 1.5 mmol, commercially available) are dissolved in toluene, the mixed solution is stirred and refluxed for 48 h, and water produced is removed. Then the solution is concentrated under vacuum, most of the solvent is removed, the product is precipitated with diethyl ether, and recrystallized with isopropyl alcohol, and dried in vacuum to obtain the target product PEG4000-DA (water-soluble compound containing ester alkyne group). The preparation equation of PEG4000-DA is as shown below:

[0049]

[0050] The water-soluble chitosan (CMC) and the crosslinking agent (PEG4000-DA) are mixed in an equal functional group ratio (i.e., the functional group ratio is 1:1) to obtain a hydrogel carrier, which is dissolved in the PBS suspension of AIE vesicles (wherein the concentration of AIE vesicles is 40 μg / mL, and the mass percentage concentration of the hydrogel carrier is 4%), and is allowed to stand and solidify for 8 h to obtain artificial stem cell vesicle hydrogel with wound repair promoting function. The equation of the amine-yne click reaction between CMC and PEG4000-DA is as shown below:

[0051]

[0052] Example 2

[0053] The difference between this embodiment and Example 1 is that in step (2), the mass ratio of AIE molecules to artificial stem cell vesicles is 1:50.

[0054] Example 3

[0055] The difference between this embodiment and Example 1 is that in step (2), the mass ratio of AIE molecules to artificial stem cell vesicles is 1:3.

[0056] Example 4

[0057] The difference between this embodiment and embodiment 1 is that in step (2), the final concentration of AIE in the AIE vesicle is about 400 μmol / L.

[0058] Example 5

[0059] The difference between this embodiment and embodiment 1 is that in step (2), the mass ratio of AIE molecule and artificial stem cell vesicle is 1:30.

[0060] Comparative Example 1

[0061] The difference between this comparative example and embodiment 1 is that in step (2), no AIE molecule is added, and after obtaining the artificial stem cell vesicle, the redundant PBS suspension is directly mixed with water-soluble chitosan (CMC) and crosslinking agent (PEG4000-DA) in the same functional group ratio.

[0062] Comparative Example 2

[0063] The difference between this comparative example and embodiment 1 is that in this comparative example, the following TCB molecule (TCB molecule belongs to AIE molecule, and its structural formula is shown below) is used instead of THB molecule in embodiment 1 to prepare TCB vesicle.

[0064]

[0065] Comparative Example 3

[0066] The difference between this comparative example and embodiment 1 is that in the AIE vesicle, the final concentration of AIE is about 500 μmol / L. It can be observed from the preparation process that the final concentration of AIE is too high, which exceeds the loading limit, and AIE cannot be well dispersed, and solid precipitate is separated out.

[0067] Test Example 1

[0068] The THB (AIE molecule) in step (1) of embodiment 1 is detected by nuclear magnetic resonance hydrogen spectrum, as shown in the nuclear magnetic resonance hydrogen spectrum of Figure 1 , it is proved that THB is successfully prepared.

[0069] The vesicle in step (2) of embodiment 1 is characterized by transmission electron microscopy, Figure 2 , the characterization of the vesicle in embodiment 1 is shown in Figure 2 (a), and the size of 100-200 nm tea cup holder structure can be observed, which proves the successful preparation of the vesicle; from Figure 2 (b), the yield of the vesicle is calculated to be 1.99×10 10 / 10 6 cells. The protein concentration of the vesicle is about 201 μg / 1010 .

[0070] PEG4000-DA in step (3) of Example 1 was detected by nuclear magnetic resonance hydrogen spectrum. Figure 3 PEG4000-DA in Example 1, as shown in the nuclear magnetic resonance hydrogen spectrum of Figure 3 PEG4000-DA was successfully prepared.

[0071] The hydrogel prepared in Example 1 was characterized by transmission electron microscopy, as shown in Figure 4 The uniformly distributed pores can be observed, indicating the successful preparation of the cross-linked network of the hydrogel.

[0072] Antibacterial test of artificial stem cell vesicle hydrogel with wound repair promoting function in Test Example 2

[0073] The antibacterial properties of the THB vesicles in step (2) of Example 1 and the TCB vesicles in Comparative Example 2 were tested as follows: different concentrations of AIE vesicles, TCB vesicles and 10 6 CFU / mL bacterial solution were prepared in a 48-well plate, incubated for 10 min, then irradiated with 100 mW / cm 2 of white light for 10 min, and then the bacterial solution was diluted to 10 4 CFU / mL, and 100 μL was taken and plated on LB plates to observe the growth of colonies.

[0074] Figure 5 The antibacterial ability experiment graph of THB vesicles on Staphylococcus aureus and Escherichia coli, as shown in Figure 5 The AIE vesicles showed significant dark toxicity to Gram-positive Staphylococcus aureus, and the antibacterial ability was enhanced after light irradiation; at the same time, the AIE vesicles also showed good antibacterial ability to Gram-negative Escherichia coli under light irradiation.

[0075] Figure 6 The antibacterial ability experiment graph of TCB vesicles on Staphylococcus aureus and Escherichia coli, as shown in Figure 6 The TCB vesicles showed significant dark toxicity to Gram-positive Staphylococcus aureus, and the antibacterial ability was enhanced after light irradiation, but the antibacterial effect was significantly worse than that of the THB vesicles in Example 1. However, the TCB vesicles did not show obvious killing ability to Gram-negative Escherichia coli. It can be seen that the THB vesicles in Example 1 have killing ability to both Gram-negative bacteria and Gram-positive bacteria, while the TCB vesicles in Comparative Example 2 only have killing ability to Gram-positive bacteria.

[0076] The artificial stem cell vesicle hydrogel with wound repair promoting function prepared in Examples 2-5 was subjected to the same antibacterial experiment, and had the same effect.

[0077] Cell proliferation-promoting artificial stem cell vesicle hydrogel of Test Example 3

[0078] The AIE vesicles in Example 1 Step (2) and the vesicles in Comparative Example 1 were subjected to a cell proliferation-promoting test, which was performed as follows: HaCaT cells were seeded in a 96-well plate at a cell density of 2.0 x 10 4 / mL, and after 24 hours of culture, the AIE vesicles in Example 1 Step (2) and the vesicles in Comparative Example 1 were used for treatment, CCK-8 reagent was added after 24 hours, and after 1 hour of incubation at 37℃, the absorbance was tested at 450 nm.

[0079] The AIE vesicles in Example 1 Step (2) and the vesicles in Comparative Example 1 were subjected to a migration performance test, which was performed as follows: the wound healing effect of the AIE vesicles in Example 1 Step (2) and the vesicles in Comparative Example 1 was evaluated in vitro by scratch test. HaCaT cells were seeded in a 6-well plate at a cell density of 1.0 x 10 5 cells were cultured to 90%, a 200 μL pipette tip was used to make parallel scratches in each well, and then the AIE vesicles in Example 1 Step (2), the vesicles in Comparative Example 1, or PBS was used for treatment, respectively. After 12 hours and 24 hours, photographs were taken using an optical microscope. A blank group and an AIE molecule control group were also set up.

[0080] Figure 7 The statistical results of the cell proliferation-promoting effect of the AIE vesicles in Example 1 Step (2) and the vesicles in Comparative Example 1 were as follows: Figure 7 It can be seen that the cell number increased significantly in a dose-dependent manner, and the AIE vesicles in Example 1 Step (2) and the vesicles in Comparative Example 1 had a significant cell proliferation-promoting function.

[0081] Figure 8 The scratch test of the AIE vesicles in Example 1 Step (2) and the vesicles in Comparative Example 1 was as follows: Figure 8 It can be seen that compared with the blank group and the AIE molecule control group, the AIE vesicles in Example 1 Step (2) and the vesicles in Comparative Example 1 had a significant promoting effect on cell migration, and the addition of the AIE molecule did not adversely affect cell proliferation and migration.

[0082] Acid-responsive release test of artificial stem cell vesicle hydrogel with wound repair-promoting function of Test Example 4

[0083] The same volume of light-powered anti-infective artificial stem cell vesicle hydrogel in Example 1 was soaked in PBS buffer with pH of 6, 7 and 8 respectively, and the absorption was measured at different time intervals and converted into the concentration of released AIE molecules, so as to calculate the percentage of gel to AIE vesicle slow release.

[0084] Figure 9 The acid response slow release capability characterization diagram of the light-powered anti-infective artificial stem cell vesicle hydrogel prepared in Example 1 is shown in Figure 2. Figure 9 It can be seen that the proportion of hydrogel to AIE vesicle slow release is significantly improved in the acidic environment with pH of 6 compared with pH of 7 and pH of 8, which shows that the acidic conditions help the targeted release of the light-powered anti-infective artificial stem cell vesicle hydrogel at the wound site.

[0085] Wound treatment test of artificial stem cell vesicle hydrogel with function of promoting wound repair in Test Example 5

[0086] The specific operation steps of the rat scald wound construction are as follows: on day 0, the standard deep Ⅱ degree scald wound model of the rat was made by using a scald instrument, the setting conditions were 500g, 95℃ and 15s, so that the scalded epidermis was yellow and hard, and collagen fibers were fused into pieces, and most of the sebaceous glands, sweat glands and hair follicles were destroyed except the deep dermis, which proved that the modeling was successful. On day 1, the scalded wound was treated, after the scalded necrotic skin was cut off, the wound was divided into 4 groups, except that the control group was only treated with normal saline, the other 3 groups were respectively coated with blank hydrogel, the vesicle-containing hydrogel prepared in Comparative Example 1 or the AIE vesicle-containing hydrogel prepared in Example 1 with the same area as the wound and the thickness of 2mm; the AIE vesicle hydrogel group was irradiated with 100mW / cm 2 of white light for 10min for photodynamic sterilization after incubation for 12h. Then the gel was replaced and photodynamic treatment was performed again on the 3rd, 7th, 14th and 21st day of treatment, and the wound recovery on the 7th and 14th day was recorded.

[0087] Figure 10 The repair-promoting effect diagram of the scalded wound of each treatment group can be seen, compared with the control group and the blank hydrogel group, the encapsulated vesicles or THB vesicles can significantly improve the healing rate of the wound, and the wound area of the hydrogel group containing vesicles or THB vesicles is significantly smaller than that of the other two groups on the 7th day of wound healing, which proves that the vesicle component encapsulated by the hydrogel has the ability to promote healing at the in vivo level; at the same time, the thickness and distribution of the bacterial film of the wound of the THB vesicle group are obviously improved, which proves that THB can kill and inhibit bacteria on the wound through photodynamic treatment. The above results show that the repair-promoting material of the application has potential application value in the field of scald wound treatment.

[0088] The same wound treatment test was carried out using the artificial stem cell vesicle hydrogel prepared in Examples 2 to 5 having a function of promoting wound repair, and the same effect was obtained.

[0089] The foregoing examples are illustrative only and are not meant to limit the scope of the methods described herein. The appended claims are intended to claim as broad a scope as possible consistent with the principles of the present invention. The examples presented herein are intended to demonstrate the principles of the present invention and are not intended to limit the scope of the claims. Some of the ranges of values are intended to cover sub-ranges of values falling within the broader ranges. The disclosure as set forth herein contemplates all such sub-ranges.

Claims

1. A photodynamic anti-infective artificial stem cell vesicle hydrogel for promoting wound repair, characterized in that, The hydrogel carrier and AIE vesicles loaded in the hydrogel carrier; the AIE vesicles are AIE molecules wrapped with artificial stem cell vesicles on the outer surface; The mass ratio of the AIE molecules and the artificial stem cell vesicles ranges from 1:3 to 50, and the maximum final concentration of the AIE molecules in the AIE vesicles is not more than 400 μmol / L; The AIE molecules have the following structural formula (I): wherein R - is an anion balancing the charge, selected from one of Cl - , Br - , I - , PF6 - ; The hydrogel carrier is prepared by the amino-alkynyl reaction of an amino-containing water-soluble polymer compound and an ester-alkynyl-containing water-soluble compound at a functional group ratio of 1-10:10-1; The amino-containing water-soluble polymer compound is water-soluble chitosan; The ester-alkynyl-containing water-soluble compound has one or more of the structures shown in any one of the following formula (II): wherein n is an integer greater than or equal to 1.

2. The hydrogel of claim 1, wherein, The artificial stem cell vesicles are derived from one or more of adipose stem cells, fibroblast stem cells, and epidermal stem cells.

3. The hydrogel of claim 1, wherein, The mass ratio of the AIE vesicles to the hydrogel carrier is 0.67-10:

1.

4. A method for preparing the hydrogel according to any one of claims 1 to 3, characterized in that, The preparation steps include: S1. Artificial stem cell lysis is performed to obtain a membrane suspension, which is extruded by a liposome extruder to obtain artificial stem cell vesicles; S2. After the artificial stem cell vesicles are co-incubated with the AIE molecules, the artificial stem cell vesicles are extruded by a liposome extruder to coat the AIE molecules with the artificial stem cell vesicles, thereby obtaining AIE vesicles; S3. An AIE vesicle aqueous solution or an AIE vesicle PBS solution is added to a precursor solution of a hydrogel carrier, and the mixture is left to solidify to obtain the photodynamic anti-infection artificial stem cell vesicle hydrogel for promoting wound repair.

5. The preparation method according to claim 4, characterized in that, In the step S3, the concentration of the AIE vesicles in the AIE vesicle aqueous solution or the AIE vesicle PBS solution ranges from 1 to 300 μg / mL, and the mass percentage concentration of the hydrogel carrier in the precursor solution of the hydrogel carrier ranges from 3 to 15%.

6. Use of the hydrogel of any one of claims 1-3 in the preparation of a wound repair material.

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