Vesicle and hydrogel based on self-assembly of natural small molecules as well as preparation method and application of vesicle and hydrogel

Abstract

The invention belongs to the field of biomedical materials, and particularly relates to vesicles and hydrogel based on natural small molecule self-assembly and a preparation method and application of the vesicles and the hydrogel, and the vesicles are hollow capsules which are formed by self-assembly of aescin hydrolysate C53H84O23 and / or C48H78O22 and have the particle size of 50-1000 nm. The natural saponin hydrolysate is taken as a basic unit, so that the cost is greatly lower than that of expensive materials such as phospholipids; meanwhile, a self-assembly system and a degradation product thereof have extremely small interference on an organism immune system, non-specific macrophage removal and inflammatory response are effectively reduced, the biological safety and the production efficiency of the hydrogel are remarkably improved, and the self-assembly hydrogel also has industrial application potentials of simplifying the process, reducing the cost and having good immune compatibility.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials, specifically relating to vesicles and hydrogels based on the self-assembly of natural small molecules, their preparation methods, and applications. Background Technology

[0002] Small molecule drugs (typically with a molecular weight of less than 1000) are widely used to treat a variety of diseases due to their small molecular weight and strong tissue penetration. However, their short in vivo half-life and low targeted delivery efficiency make it difficult to achieve sustained and precise drug release, thus limiting their clinical efficacy.

[0003] Therefore, the use of hydrogels with three-dimensional network structures for loading and delivering small molecule drugs has been widely applied in the biomedical field. However, traditional hydrogel preparation often relies on chemical cross-linking (such as acrylate polymerization and glutaraldehyde cross-linking), which introduces potentially toxic reagents, leading to decreased biocompatibility. For example, although polyacrylamide hydrogels have high mechanical strength (G′ > 1 kPa), their network rigidity can easily trigger sudden drug release; sodium alginate hydrogels have good biocompatibility, but they rely on calcium ion cross-linking, and long-term use may disrupt the body's calcium balance. These shortcomings severely limit the application of traditional hydrogels in precise drug delivery and dynamic microenvironment regulation.

[0004] In recent years, small molecule self-assembly systems (such as liposomes) have attracted attention due to their advantage of not requiring chemical cross-linking, but they still face multiple challenges: (1) they have stringent requirements for storage environment, requiring strict temperature and pressure control; (2) the raw material cost is high (30mg of phosphatidylcholine costs about 5,000 yuan); and (3) the potential risk of immunogenicity has not been eliminated. These problems together hinder the promotion and application of self-assembly carriers in clinical practice.

[0005] To address the above problems, this invention is proposed. Summary of the Invention

[0006] To overcome the above-mentioned technical defects and application limitations, this invention provides a vesicle and hydrogel based on the self-assembly of natural small molecules, as well as their preparation methods and uses. The hydrogel prepared from the vesicle and the drug-loaded gel prepared from the drug-loaded vesicle have the advantages of high biocompatibility and mild self-assembly, and can effectively inhibit immunogenic reactions while simplifying storage conditions and reducing preparation costs.

[0007] The technical solution adopted by the present invention is as follows: The first aspect of the present invention provides vesicles based on the self-assembly of natural small molecules, wherein the vesicles are derived from the hydrolysis product C of aescin. 53 H 84 O 23 and / or C 48 H 78 O 22Hollow capsules with a particle size of 50-1000 nm formed by self-assembly.

[0008] Preferably, the vesicles are closed.

[0009] A second aspect of the present invention provides a method for preparing the vesicles described in the first aspect, the method comprising the following steps:

[0010] Step (1): Mix aescin and water to hydrolyze aescin and obtain a dispersion of hydrolysate;

[0011] Step (2): Incubate the hydrolysis product dispersion obtained in step (1) to obtain a vesicle dispersion.

[0012] In step (1), aescin undergoes hydrolysis upon contact with water, generating hydrolysis product 1 and / or hydrolysis product 2.

[0013] No deliberate control is made over whether aescin forms hydrolysis product 1 or hydrolysis product 2, because either one or both can self-assemble into vesicles, so let nature take its course.

[0014] There are no restrictions on the ratio of aescin to water in step (1), but if the ratio is too low, the concentration of the hydrolysate dispersion will be too low, resulting in a low concentration of the vesicle dispersion obtained after incubation in step (2), which is unsuitable for large-scale production. If the ratio is too high, the concentration of the hydrolysate dispersion will be too high, which may cause a decrease in vesicle stability or exceed the critical micelle concentration, thus forming micelles instead of vesicles. From the perspective of industrial production, preferably, the mixing ratio of water and aescin in step (1) is 0.5-100 mg of aescin per 1 ml of water. Preferably, the hydrolysis is also treated with ultrasound assistance at a power of 50-300 W for 10-20 minutes, which helps the hydrolysate to be evenly dispersed in water. Of course, ultrasound assistance is not required in step 1.

[0015] Preferably, the incubation conditions in step (2) are incubation at a constant temperature water bath of 35-40℃ for 2-48 hours.

[0016] The vesicle dispersion can be freeze-dried to remove the medium water and obtain vesicle powder.

[0017] A third aspect of the present invention provides a hydrogel formed from the vesicles described in the first aspect, wherein the hydrogel is a three-dimensional network structure assembled from the vesicles.

[0018] Preferably, the hydrogel does not contain chemical cross-linking agents. This is because the vesicle dispersion shown below can be gelled simply by adjusting the pH (e.g., by adding an aqueous NaOH solution), thus eliminating the need for additional chemical cross-linking agents that could have negative effects on organisms.

[0019] The fourth aspect of the present invention provides a method for preparing the hydrogel described in the third aspect, wherein the method involves gelling the obtained vesicle dispersion to form the hydrogel.

[0020] Preferably, the gelation conditions are to adjust the vesicle dispersion to pH 8-13, and then incubate it in a constant temperature water bath at 35-40℃ for 2-48 hours.

[0021] The fifth aspect of this invention provides drug-loaded vesicles based on the self-assembly of natural small molecules, wherein the drug-loaded vesicles are derived from the hydrolysis product C of aescin. 53 H 84 O 23 and / or C 48 H 78 O 22 Hollow capsules with a particle size of 50-1000 nm are formed by self-assembly and contain at least a small molecule hydrophobic drug.

[0022] Preferably, the drug-loaded vesicles are closed.

[0023] Preferably, the small molecule hydrophobic drug refers to a hydrophobic drug with a molecular weight of less than 1000.

[0024] The drug-loaded vesicle dispersion can be freeze-dried to remove the medium water to obtain drug-loaded vesicle powder, and the drug-loaded gel can also be freeze-dried to remove the medium water to obtain drug-loaded gel powder.

[0025] A sixth aspect of the present invention provides a method for preparing the drug-loaded vesicles described in the fifth aspect, the method comprising the following steps:

[0026] Step (1): Mix aescin, water and small molecule hydrophobic drug to obtain a mixed dispersion;

[0027] Step (2): Incubate the mixed dispersion obtained in step (1) to obtain a drug-loaded vesicle dispersion.

[0028] Preferably, in step (1), the addition ratio of aescin, water, and small molecule hydrophobic drug is 0.5-100mg aescin and 0.5-12mg small molecule hydrophobic drug to 1ml of water; the mixture is then treated with ultrasound at a power of 50-300W for 10-20 minutes.

[0029] Preferably, the incubation conditions in step (2) are incubation at a constant temperature water bath of 35-40℃ for 2-48 hours.

[0030] The seventh aspect of the present invention provides a drug-loaded hydrogel formed from the drug-loaded vesicles described in the fifth aspect, wherein the drug-loaded hydrogel has a three-dimensional network structure.

[0031] The eighth aspect of the present invention provides a method for preparing the drug-loaded hydrogel described in the seventh aspect, wherein the method involves gelling the drug-loaded vesicles to form the drug-loaded hydrogel.

[0032] Preferably, the gelation conditions are to adjust the system to pH 8-13 and then incubate it in a constant temperature water bath at 35-40℃ for 2-48 hours.

[0033] The ninth aspect of the present invention provides the use of the vesicles described in the first aspect or the hydrogels described in the third aspect for loading and delivering small molecule hydrophobic drugs.

[0034] The present invention has the following beneficial effects:

[0035] 1. This invention utilizes natural small molecule C 53 H 84 O 23 and / or C 48 H 78 O 22 Vesicles are self-assembled through non-covalent interactions, each vesicle having a hollow cavity and a cortex, both of which can serve as drug carriers. The present invention also produces drug-loaded vesicles accordingly.

[0036] 2. The vesicles of the present invention can be further incubated into hydrogels, completely eliminating the need for chemical cross-linking agents. They can be prepared simply by adjusting the pH value and incubating under constant temperature and other mild conditions, avoiding high temperature and high pressure conditions, and having low requirements for instruments and operating environment, which is conducive to large-scale production, transportation and storage.

[0037] 3. Using natural saponin hydrolysates as basic units, the cost is significantly lower than that of expensive materials such as phospholipids; at the same time, the self-assembled system and its degradation products have minimal interference with the body's immune system, effectively reducing non-specific macrophage clearance and inflammatory response, significantly improving the biosafety and production efficiency of hydrogels, and also having the potential for industrial application with simplified processes, reduced costs and good immunocompatibility. Attached Figure Description

[0038] Figure 1 The structural formula of aescin;

[0039] Figure 2 In the specific implementation method, hydrolysis product 1, namely C, is... 53 H 84 O 23 The structural formula;

[0040] Figure 3 In the specific implementation method, hydrolysis product 1, namely C, is... 53 H 84 O 23 The corresponding mass spectrum;

[0041] Figure 4In the specific implementation method, hydrolysis product 2, namely C, is... 48 H 78 O 22 The structural formula;

[0042] Figure 5 In the specific implementation method, hydrolysis product 2, namely C, is... 48 H 78 O 22 The corresponding mass spectrum;

[0043] Figure 6 This is a model diagram of a vesicle in a specific implementation method;

[0044] Figure 7 The images shown are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of vesicles in a specific embodiment. 7a is an SEM image of a vesicle after it has been deliberately disintegrated to show the hollow vesicle structure. 7b is an SEM image of a vesicle. 7c is a TEM image of a vesicle.

[0045] Figure 8 Here is a scanning electron microscope image of the hydrogel in a specific embodiment;

[0046] Figure 9 This is a visual representation of the hydrogel in a specific implementation method;

[0047] Figure 10 The following is a diagram showing the ultraviolet scanning curves of drug-loaded vesicles and the evaluation of treatment effects in a specific implementation method. Figure 10 a shows the common absorption peak of drug-loaded vesicles and colchicine at 354 nm. Figure 10 b shows the improvement in ejection fraction after 28 days of treatment for myocardial infarction;

[0048] Figure 11 This is a graph showing the evaluation of inflammatory markers by vesicles and drug-loaded vesicles in vivo in a specific embodiment. Figure 11 a shows the effect on high-sensitivity C-reactive protein (CRP). Figure 11 b shows the effect on tumor necrosis factor (TNF-α). Figure 11 c shows the effect on interleukin-6 (IL-6). Figure 11 d shows the effect on interleukin-10 (IL-10);

[0049] Figure 12 The hydrogel viscosity scanning curve is shown in the specific implementation method.

[0050] Figure 13 The hydrogel frequency scanning curve is shown in the specific implementation method.

[0051] Figure 14 The strain scanning curve of the hydrogel is shown in the specific implementation method.

[0052] Figure 15 The hydrogel strain step scan curve is shown in the specific implementation embodiment.

[0053] Figure 16 The drug release curve of the drug-loaded vesicle hydrogel is shown in the specific implementation embodiment. Detailed Implementation

[0054] The present invention will be further described below through embodiments, but is not limited to these embodiments. Experimental methods not specifically described in the embodiments generally use conventional conditions and conditions described in manuals, or conditions recommended by the manufacturer. The general equipment, materials, reagents, etc., used are all commercially available unless otherwise specified.

[0055] Example 1

[0056] This embodiment discloses a method for preparing vesicles based on the self-assembly of natural small molecules, the method comprising the following steps:

[0057] Step (1) Add 30mg of aescin (C 55 H 86 O 24 Dissolve the aescin in 3 ml of water and sonicate for 10 minutes under ultrasonic assistance at 100 W. The ester groups of the aescin in the system are hydrolyzed to obtain a dispersion of hydrolysate; wherein the hydrolysate 1C 53 H 84 O 23 See appendix for the structural formula. Figure 2 The corresponding mass spectrum is shown in the appendix. Figure 3 ; and hydrolysis product 2: C 48 H 78 O 22 See appendix for the structural formula. Figure 4 The corresponding mass spectrum is shown in the appendix. Figure 5 ;

[0058] Step (2) The hydrolysis product dispersion obtained in step (1) is placed in a constant temperature water bath at 40℃ and incubated for 36 hours to form a vesicle dispersion.

[0059] To observe the vesicle structure prepared in this embodiment, imaging analysis was performed using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Figure 7 b and Figure 7 c shows the SEM and TEM images of the vesicles, respectively. To further reveal the internal structure of the vesicles, the prepared vesicles were treated at 60℃ for 1 min to cause them to disintegrate, and then SEM scans were performed again. The resulting images are shown below. Figure 7 As shown in a.

[0060] In addition, the vesicle model in the vesicle dispersion prepared in this embodiment can be referred to the appendix. Figure 6 .

[0061] Example 2

[0062] This embodiment discloses a method for preparing hydrogels using the vesicles obtained in Example 1. The method involves adding sodium hydroxide solution to the vesicle dispersion prepared in Example 1 to adjust the system to pH = 9, and then incubating it in a constant temperature water bath at 40°C for 36 hours to obtain the hydrogel.

[0063] To observe the structure of the hydrogel prepared in this embodiment, scanning electron microscopy (SEM) was used for imaging analysis, as detailed in [link to documentation]. Figure 8 As shown.

[0064] Additionally, a visual representation of the hydrogel prepared in this embodiment can be found in the attached diagram. Figure 9 .

[0065] Example 3

[0066] This embodiment provides a method for preparing drug-loaded vesicles based on the self-assembly of natural small molecules, including the following steps:

[0067] Step (1): Add 30mg of aescin (C 55 H 86 O 24 ), 3mg colchicine (C 21 H 25 ClO6) was dissolved in 3 ml of water, and then ultrasonically treated for 10 minutes at 100 W power to obtain a mixed dispersion.

[0068] Step (2) The mixed dispersion obtained in step (1) is placed in a constant temperature water bath at 40°C for 36 hours to form a drug-loaded vesicle dispersion.

[0069] To demonstrate that the hydrophobic small molecule colchicine was loaded onto vesicles, we used a UV spectrophotometer to scan colchicine and the colchicine-loaded vesicles prepared in this example, as shown below. Figure 10 As shown in Figure a, it can be seen that the drug-loaded vesicles and colchicine in this embodiment share a common absorption peak at 354 nm, indicating that the vesicles in this embodiment have been loaded with colchicine.

[0070] To evaluate the therapeutic effect of colchicine-loaded vesicles on myocardial infarction, this embodiment also conducted a 28-day animal model efficacy observation experiment, focusing on monitoring the dynamic changes in left ventricular ejection fraction using echocardiography. Figure 10As shown in b, after 28 days of treatment, the ejection fraction in the colchicine-loaded vesicle group (50.5% ± 1.73%) was significantly higher than that in the untreated control group (39.25% ± 2.64%) and the direct treatment group with free colchicine (39% ± 3.37%). This result indicates that, compared to traditional free drug delivery methods, vesicle-based delivery systems can more efficiently deliver colchicine to the myocardial injury area, significantly improve the myocardial repair process, and promote the recovery of cardiac contractile function.

[0071] Among them, the appendix Figure 10 In section b, the sham-operated group refers to experimental animals that receive the same anesthesia, surgical incision, and procedures as the experimental group (myocardial infarction model group), but without undergoing the crucial disease induction steps. In this experiment, the sham-operated group animals undergo open-chest surgery, but the coronary arteries are not ligated, thus not actually inducing myocardial ischemia or infarction. The purpose of providing the sham-operated group is: 1. to eliminate the influence of the surgical procedure itself; 2. to verify whether the myocardial infarction model has been successfully established. Figure 10 In column b, the untreated control group corresponds to the untreated myocardial infarction group for 28 days, which is the second column; the free colchicine treatment group corresponds to the myocardial infarction + colchicine intervention group for 28 days, which is the fourth column; and the colchicine-loaded vesicle group corresponds to the myocardial infarction + colchicine-loaded vesicle intervention group for 28 days, which is the fifth column.

[0072] To further evaluate the effects of vesicles and drug-loaded vesicles on nonspecific macrophage responses and inflammatory markers, this example also observed serum inflammatory markers (CRP, TNF-α, IL-6, and IL-10) in animals at 1 day and 3 days. The results are as follows:

[0073] like Figure 11 As shown in a, the CRP values ​​in the blank vesicle group on days 1 and 3 (values ​​of 42.60±4.20 ng / ml and 35.80±3.20 ng / ml, respectively) were not significantly higher than those in the untreated control group (values ​​of 44.80±4.75 ng / ml and 37.60±3.95 ng / ml, respectively).

[0074] like Figure 11 As shown in b, the TNF-α levels in the blank vesicle group on days 1 and 3 (values ​​of 114.20±11.50 pg / ml and 89.70±8.90 pg / ml, respectively) were not significantly higher than those in the untreated control group (values ​​of 118.50±10.20 pg / ml and 92.40±9.80 pg / ml, respectively).

[0075] like Figure 11As shown in c, the IL-6 level in the blank vesicle group on day 1 (value was 300.00±34.20 pg / ml) was significantly lower than that in the untreated control group (value was 453.3±54.5 pg / ml); the IL-6 level in the blank vesicle group on day 3 (value was 280.80±24.5 pg / ml) was not significantly higher than that in the untreated control group (value was 300.2±42.3 pg / ml).

[0076] like Figure 11 As shown in d, the IL-10 values ​​in the blank vesicle group on days 1 and 3 (values ​​of 19.50±2.10 pg / ml and 22.80±3.10 pg / ml, respectively) were not significantly different from those in the untreated control group (values ​​of 17.80±2.90 pg / ml and 21.60±3.50 pg / ml, respectively).

[0077] The blank vesicle group and the untreated control group correspond to the attached [reference]. Figure 11 The figures are divided into two groups: the myocardial infarction group with blank vesicle intervention and the myocardial infarction group without intervention (bar charts). Additionally, in the figure, a represents the comparison between the sham surgery group and the myocardial infarction group without intervention (P < 0.05); b represents the comparison between the sham surgery group and the myocardial infarction group with blank vesicle intervention (P < 0.05); c represents the comparison between the sham surgery group and the myocardial infarction group with colchicine intervention (P < 0.05); d represents the comparison between the sham surgery group and the myocardial infarction group with colchicine-loaded vesicle intervention (P < 0.05); e represents the comparison between the myocardial infarction group without intervention and the myocardial infarction group with blank vesicle intervention (P < 0.05); f represents... The comparison between the uninterventional group of myocardial infarction and the group treated with colchicine was P<0.05; g indicates the comparison between the uninterventional group of myocardial infarction and the group treated with colchicine-loaded vesicles, P<0.05; h indicates the comparison between the group treated with colchicine-loaded vesicles and the group treated with blank vesicles, P<0.05; i indicates the comparison between the group treated with colchicine-loaded vesicles and the group treated with blank vesicles, P<0.05; j indicates the comparison between the group treated with colchicine-loaded vesicles and the group treated with colchicine-loaded vesicles, P<0.05.

[0078] Based on the above test results, the vesicle-based delivery system did not induce nonspecific macrophage responses or inflammatory responses.

[0079] Example 4

[0080] This embodiment discloses a method for preparing drug-loaded hydrogels using the drug-loaded vesicles obtained in Example 3. The method involves adding sodium hydroxide solution to the drug-loaded vesicle dispersion prepared in Example 3, adjusting the system to pH=9, and then incubating it in a constant temperature water bath at 40°C for 36 hours to obtain the drug-loaded hydrogel.

[0081] Test Example 1

[0082] In this test example, the hydrogel samples obtained in Example 2 were subjected to rheological tests using a rotational rheometer.

[0083] (1) Perform dynamic frequency scanning, where the strain is set to 1% and the angular frequency range is from 0.1 rad / s to 100 rad / s. Under the same strain, evaluate the stability and viscoelastic response characteristics of the network structure by measuring the storage modulus (G'), loss modulus (G”), and viscosity as a function of frequency at different angular frequencies.

[0084] (2) Perform strain-dependent scanning, with the strain range from 0.01% to 100%. Determine the linear viscoelastic range and yield point of the material, and evaluate the structural integrity under different deformation intensities.

[0085] (3) A step strain experiment was conducted to verify the self-healing ability of the hydrogel.

[0086] The experiment consisted of two steps: First, the strain was set to 0.1% and maintained for 2.5 minutes; then, the strain was increased from 0.1% to 60% and maintained for 2.5 minutes to completely disrupt the hydrogel structure; finally, the strain was reduced back to 0.1% and maintained for 2.5 minutes to observe whether the gel could recover. The entire experiment was conducted at 25°C, with a frequency maintained at 10 rad / s, and the mass concentration of the hydrogel was 10 mg / mL.

[0087] The results are as follows Figure 12 , 13 As shown in 14 and 15, Figure 12 The hydrogel exhibits high viscosity at low shear rates, demonstrating its ability to effectively prevent sedimentation, which is crucial for storage stability.

[0088] Figure 13 Dynamic frequency scanning showed that the storage modulus (G') was about 10 times that of the loss modulus (G”), indicating that the hydrogel has high stability.

[0089] Figure 14 With increasing shear rate, viscosity decreases, exhibiting typical shear-thinning characteristics, making it suitable for injection molding. When the strain exceeds 26.9%, G” exceeds G’, and the hydrogel transitions from a gel state to a solution state. In step strain experiments ( Figure 15 The hydrogel maintained its gel state at 0.1% strain, but at a high strain of 60%, G' decreased rapidly, the gel structure was disrupted, and it transitioned to a solution state. Upon recovery of the strain to 0.1%, G' rebounded immediately, demonstrating a rapid and complete self-healing ability. This self-healing ability is attributed to the dynamic hydrogen bonds between carbohydrates and the van der Waals forces between rigid steroidal rings.

[0090] Overall, hydrogels exhibit excellent rheological properties, including high stability, shear-thinning characteristics, good injection performance, and self-healing ability, demonstrating their potential application value in targeted drug delivery and controlled release.

[0091] Test Example 2

[0092] This test case demonstrates an in vitro drug release test of a hydrogel loaded with colchicine.

[0093] Three hydrogels loaded with colchicine prepared in Example 4 were immersed in distilled water and shaken at 37°C and 60 rpm / min. At preset time intervals (3 hours, 6 hours, 12 hours, 24 hours, 36 hours, 48 ​​hours, 60 hours, 72 hours, 84 hours, 96 hours, and 108 hours), 1 mL of supernatant was taken from each sample for in vitro drug release testing, and an equal volume of distilled water was added to maintain a constant volume.

[0094] The specific testing method was as follows: the absorbance of the supernatant was measured at a wavelength of 354 nm using a UV-Vis spectrophotometer, and the cumulative release of colchicine at 3 hours, 6 hours, 12 hours, 24 hours, 36 hours, 48 ​​hours, 60 hours, 72 hours, 84 hours, 96 hours, and 108 hours was calculated to be 10%, 17%, 23%, 34%, 43%, 51%, 57%, 62%, 67%, 73%, and 79%, respectively.

[0095] The results obtained are as follows Figure 16 The results show that drug release exhibits a typical three-stage behavior. During the initial 6 hours, release is rapid, as water molecules quickly penetrate the hydrogel, causing colchicine to diffuse under the influence of a large concentration gradient between the hydrogel and the release medium, resulting in a significant cumulative release. Subsequently, the release rate begins to slow, increasing to approximately 34% within 24 hours. In the later stages, the drug release rate further decreases and tends to stabilize, at which point the drug is mainly released synchronously with the slow degradation process of the hydrogel.

[0096] Overall, drug-loaded hydrogels exhibit rapid initial release and sustained later release, which contributes to long-term sustained drug release and biocompatibility, meeting the needs of drug delivery systems.

[0097] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. Vesicles based on the self-assembly of natural small molecules, characterized in that, The vesicles are composed of aescin hydrolysis product C. 53 H 84 O 23 and / or C 48 H 78 O 22 Hollow vesicles with a particle size of 50-1000 nm are formed by self-assembly, and preferably the vesicles are closed.

2. A method for preparing the vesicles according to claim 1, characterized in that, The method includes the following steps: Step (1): Mix aescin and water to hydrolyze aescin and obtain a dispersion of hydrolysate; Step (2): Incubate the hydrolysis product dispersion obtained in step (1) to obtain a vesicle dispersion.

3. The method for preparing vesicles according to claim 2, characterized in that, In step (1), the mixing ratio of water and aescin is 0.5-100mg of aescin to 1ml of water; preferably, the hydrolysis is further performed under ultrasonic assistance at a power of 50-300W for 10-20 minutes. The incubation conditions in step (2) are as follows: incubation for 2-48 hours under a constant temperature water bath at 35-40℃.

4. A hydrogel formed from the vesicles of claim 1, characterized in that, The hydrogel is a three-dimensional network structure assembled from the vesicles, and the hydrogel does not contain any chemical cross-linking agents.

5. A method for preparing the hydrogel according to claim 4, characterized in that, The method involves gelling the obtained vesicle dispersion to form the hydrogel. The gelation conditions are as follows: adjust the vesicle dispersion to pH 8-13, and then incubate it in a constant temperature water bath at 35-40℃ for 2-48 hours.

6. A drug-loaded vesicle based on the self-assembly of natural small molecules, characterized in that, The drug-loaded vesicles are composed of aescin hydrolysis product C. 53 H 84 O 23 and / or C 48 H 78 O 22 Hollow vesicles with a particle size of 50-1000 nm are formed by self-assembly and are loaded with at least a small molecule hydrophobic drug; wherein the drug-loaded vesicles are closed and the small molecule hydrophobic drug refers to a compound with a molecular weight of less than 1000.

7. A method for preparing the drug-loaded vesicles according to claim 6, characterized in that, The method includes the following steps: Step (1): Mix aescin, water and small molecule hydrophobic drug to obtain a mixed dispersion; Step (2): Incubate the mixed dispersion obtained in step (1) to obtain a drug-loaded vesicle dispersion.

8. The preparation method according to claim 7, characterized in that, In step (1), the addition ratio of aescin, water, and small molecule hydrophobic drug is 0.5-100mg aescin and 0.5-12mg small molecule hydrophobic drug per 1ml of water; the mixture is treated with ultrasound at a power of 50-300W for 10-20 minutes; the incubation conditions in step (2) are 2-48 hours in a constant temperature water bath at 35-40℃.

9. A drug-loaded hydrogel formed from drug-loaded vesicles according to claim 8, characterized in that, The drug-loaded hydrogel has a three-dimensional network structure.

10. A method for preparing the drug-loaded hydrogel according to claim 9, characterized in that, The method involves gelling the aforementioned drug-loaded vesicles to form the drug-loaded hydrogel. The gelation conditions are as follows: adjust the drug-loaded vesicle dispersion to pH 8-13, and then incubate it in a constant temperature water bath at 35-40℃ for 2-48 hours.

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