CN118662428A - A gel based on stereocomplex action and its preparation method and application - Google Patents

Abstract

The present invention provides a gel based on stereocomplexation, and a preparation method and application thereof. The raw material for preparing the gel is a gel composition, and the composition includes a first block copolymer, a second block copolymer and a polysaccharide; the first block copolymer includes a poly-L-lactic acid block and a polyethylene glycol block, and the second block copolymer includes a poly-D-lactic acid block and a polyethylene glycol block. The first block copolymer is recorded as PLLA-PEG, and the second block copolymer is recorded as PDLA-PEG. In the gel, the network structure of the hydrophilic PEG and the network structure of the hydrophilic polysaccharide are interpenetrated, and a stereocomplexation occurs between the poly-L-lactic acid PLLA and the poly-D-lactic acid PDLA. This stereocomplexation can be regarded as physical crosslinking points one by one, thereby forming a gel with mechanical properties. The preparation method of the gel is simple, and the properties of the obtained gel are adjustable.

Description

A gel based on stereocomplex action and its preparation method and application

Technical Field

The invention belongs to the technical field of gel, and in particular relates to a gel composition, a gel based on stereocomplexation, and a preparation method and application thereof.

Background Art

Polyethylene glycol (PEG) is an inert, biocompatible synthetic polymer composed of polyoxy units formed by the ring-opening polymerization of ethylene oxide. Due to its excellent properties such as non-toxicity, non-immunogenicity, and high water solubility, PEG has been approved by the U.S. Food and Drug Administration for various biomedical uses.

Polylactic acid (PLA) is one of the most common biodegradable polymers, used in various fields such as renewable and biomedical. Polylactic acid forms two enantiomers: poly-L-lactic acid (PLLA) and poly-D-lactic acid (PDLA), which can form racemates through hydrogen bonds, the so-called stereocomplexes. Compared with the single enantiomers, the polylactic acid stereocomplexes show better physical properties, such as higher melting point, higher mechanical strength, and better thermal stability and hydrolytic stability. These unique properties are conducive to the application of polylactic acid in the biomedical field. In the field of biomedicine, some scholars have gradually begun to try to prepare drug controlled release systems such as micelles, microspheres and nanoparticles containing polylactic acid stereocomplexes. However, due to its strict preparation conditions, polylactic acid stereocomplexes have not been widely used in the medical field.

Summary of the invention

In order to improve the deficiencies of the prior art, the purpose of the present invention is to provide a composition for polysaccharide-polylactic acid gel based on the stereocomplexation of polylactic acid, a gel formed by the composition and a preparation method thereof, wherein the gel has excellent mechanical properties; the preparation method of the gel is simple, and the properties of the obtained gel are adjustable. Most importantly, the gel formed by the stereocomplexation of polylactic acid as the "crosslinking point" of the gel has many advantages over the gel prepared by other crosslinking methods, such as being obtained by reaction under mild conditions, avoiding the use of catalysts, auxiliary crosslinking agents and other active molecules, thereby eliminating the purification step of the gel, avoiding the residue of toxic catalysts, crosslinking agents, etc., and increasing the biosafety of the gel.

The objective of the present invention is achieved through the following technical solutions:

A composition for gel, comprising a first block copolymer, a second block copolymer and polysaccharide; the first block copolymer comprises a poly-L-lactic acid block and a polyethylene glycol block, and the second block copolymer comprises a poly-D-lactic acid block and a polyethylene glycol block.

In the present invention, the first block copolymer is recorded as PLLA-PEG, the second block copolymer is recorded as PDLA-PEG, the poly (L-lactic acid) block is recorded as PLLA block, the poly (D-lactic acid) block is recorded as PDLA block, and the polyethylene glycol block is recorded as PEG block.

The present invention proposes for the first time a composition comprising PLLA-PEG, PDLA-PEG and polysaccharide. When the composition is used to form a product, such as a gel, the hydrophilic polyethylene glycol PEG segment and the hydrophilic polysaccharide segment will form an interpenetrating network structure, and a stereocomplexation occurs between the poly-L-lactic acid PLLA segment and the poly-D-lactic acid PDLA segment. This stereocomplexation can be regarded as physical cross-linking points one by one, specifically forming a structure as shown in FIG1 .

According to an embodiment of the present invention, the polyethylene glycol block is derived from a polymer represented by formula A:

In formula A, R' is a central molecular group, Y is selected from -O-, -NH-, -C(=O)O- or -OC(=O)-, x is the degree of polymerization, and p is an integer ≥2.

According to an embodiment of the present invention, in formula A, R' is selected from a hydrocarbon group. Preferably, in formula A, R' is selected from an alkyl group, an alkenyl group, and an aryl group.

According to an embodiment of the present invention, in formula A, R' is selected from C _1-44 hydrocarbon group. Preferably, in formula A, R' is selected from C _1-44 alkyl, C _2-44 alkenyl, C _6-44 aryl. Preferably, in formula A, R' is selected from C _1-24 alkyl, C _2-24 alkenyl, C _6-24 aryl. Preferably, in formula A, R' is selected from C _1-12 alkyl, C _2-12 alkenyl, C _6-12 aryl. Preferably, in formula A, R' is selected from C _1-6 alkyl, C _2-6 alkenyl, C _6-10 aryl.

According to an embodiment of the present invention, when p is 2, the polyethylene glycol shown in formula A is also called double-arm polyethylene glycol. When p is an integer ≥ 3, the polyethylene glycol shown in formula A is also called multi-arm polyethylene glycol. Preferably, p is an integer between 2-16.

Exemplarily, the multi-arm polyethylene glycol is, for example, three-arm polyethylene glycol, four-arm polyethylene glycol, five-arm polyethylene glycol, six-arm polyethylene glycol, seven-arm polyethylene glycol, eight-arm polyethylene glycol, nine-arm polyethylene glycol, ten-arm polyethylene glycol, eleven-arm polyethylene glycol, twelve-arm polyethylene glycol, thirteen-arm polyethylene glycol, fourteen-arm polyethylene glycol, fifteen-arm polyethylene glycol or sixteen-arm polyethylene glycol.

According to an embodiment of the present invention, in the composition, the mass ratio of PLLA-PEG to PDLA-PEG is 0.001-1000:1, preferably 0.1-10:1, for example, 0.001:1, 0.005:1, 0.01:1, 0.05:1, 0.1:1, 0.5:1, 1:1, 5:1, 10:1, 50:1, 100:1, 200:1, 400:1, 500:1, 800:1 or 1000:1.

According to an embodiment of the present invention, in the composition, the mass ratio of the sum of the masses of PLLA-PEG and PDLA-PEG to the polysaccharide is 0.001-1000:1, preferably 0.1-100:1, for example, 0.001:1, 0.005:1, 0.01:1, 0.05:1, 0.1:1, 0.5:1, 1:1, 5:1, 10:1, 50:1, 100:1, 200:1, 400:1, 500:1, 800:1 or 1000:1.

The study found that when the composition contains both PLLA and PDLA, it is conducive to the formation of stereocomplexation. When the mass ratio between PLLA-PEG, PDLA-PEG and polysaccharide in the composition is adjusted, the "physical cross-linking points" formed by the stereocomplexation in the obtained gel can be adjusted. When the content of PLLA-PEG and PDLA-PEG in the composition accounts for a large proportion, the more "physical cross-linking points" formed by the stereocomplexation in the gel, the more stable the gel, the stronger the mechanical strength, and the less prone to degradation; when the content of polysaccharide in the composition accounts for a large proportion, the fewer "physical cross-linking points" formed by the stereocomplexation in the gel, the more unstable the gel, the weaker the mechanical strength, and the easier it is to degrade.

According to an embodiment of the present invention, the molecular weight of the PLLA-PEG is 200Da to 7×10 ⁵ Da, preferably 2500Da to 4×10 ⁴ Da.

According to an embodiment of the present invention, the molecular weight of the PDLA-PEG is 200Da to 7×10 ⁵ Da, preferably 2500Da to 4×10 ⁴ Da.

According to an embodiment of the present invention, in the PLLA-PEG, the molecular weight of the PEG block is 50Da-6×10 ⁵ Da, preferably 1000Da-4×10 ⁴ Da; the molecular weight of the PLLA block is 100Da-1×10 ⁵ Da, preferably 800Da-6000Da.

According to an embodiment of the present invention, in the PDLA-PEG, the molecular weight of the PEG block is 50Da-6×10 ⁵ Da, preferably 1000Da-4×10 ⁴ Da; the molecular weight of the PDLA block is 100Da-1×10 ⁵ Da, preferably 800Da-6000Da.

Studies have found that when the molecular weight of the PLLA block or the PDLA block is within the above range, it is more conducive to the formation of "physical cross-linking points".

According to an embodiment of the present invention, preferably, the molecular weight of the PLLA-PEG is the same as the molecular weight of the PDLA-PEG. Exemplarily, the molecular weight of the PEG block in the PLLA-PEG is the same as the molecular weight of the PEG block in the PDLA-PEG, and the molecular weight of the PLLA block is the same as the molecular weight of the PDLA block.

In the present invention, unless otherwise specified, molecular weight refers to number average molecular weight.

According to an embodiment of the present invention, the PLLA block is derived from a polymer represented by formula B:

Here, a is the degree of polymerization.

According to an embodiment of the present invention, the PDLA block is derived from a polymer represented by formula C:

Wherein, b is the degree of polymerization.

According to an embodiment of the present invention, in the PLLA-PEG, the PLLA block and the PEG block are connected via a linking group, and the linking group is not particularly limited, for example, -COO-.

According to an embodiment of the present invention, in the PDLA-PEG, the PDLA block and the PEG block are connected via a linking group, and the linking group is not particularly limited, for example, -COO-.

According to an embodiment of the present invention, the PLLA-PEG and the PDLA-PEG may be commercially available products, or may be prepared by methods known in the art.

According to an embodiment of the present invention, the PLLA-PEG can be prepared, for example, by the following method:

Polyethylene glycol (PEG), L-lactic acid (L-LA) and a catalyst are mixed and reacted to prepare the PLLA-PEG.

According to an embodiment of the present invention, the PDLA-PEG can be prepared, for example, by the following method:

Polyethylene glycol (PEG), dextrorotatory lactic acid (D-LA) and a catalyst are mixed and reacted to prepare the PDLA-PEG.

According to an embodiment of the present invention, PEG and L-LA are mixed in an amount according to the designed link length. Alternatively, PEG and D-LA are mixed in an amount according to the designed link length.

According to an embodiment of the present invention, the catalyst is, for example, selected from Sn(Oct) ₂ . The catalyst is added in an amount of 0.01 to 5 wt % of the total weight of the mixed system (PEG and L-LA, or PEG and D-LA).

According to an embodiment of the present invention, the reaction is carried out in the presence of an organic solvent. For example, the organic solvent is toluene.

According to an embodiment of the present invention, the reaction temperature is 110-130° C., and the reaction time is 16-36 hours. Exemplarily, the reaction temperature is 120° C., and the reaction time is 24 hours.

According to an embodiment of the present invention, after the reaction is completed, the method further comprises: filtering after settling with ethanol; dissolving with dichloromethane and settling with a cold ether/ethanol mixed solvent three times; and vacuum drying.

According to an embodiment of the present invention, the polyethylene glycol (PEG) has a structural formula shown in Formula A:

In formula A, R', Y, x and p are as defined above.

According to an embodiment of the present invention, the polysaccharide is a water-soluble polysaccharide and its derivatives.

According to an embodiment of the present invention, the polysaccharide includes at least one of the following compounds based on nature or modified by chemical, physical, or biological methods: hyaluronic acid, agar, alginate, collagen, gelatin, carrageenan, cellulose, chitosan, chitin, cyclodextrin, dextran, gellan gum, glycogen, glycosaminoglycan, karaya gum, inulin, pectin, polydextrose, xanthan gum, and starch, and any pharmaceutically acceptable salts thereof; modification methods include but are not limited to dextrinization, hydrolysis, sulfation, phosphorylation, acetylation, alkylation, hydroxyalkylation, selenization, carboxymethylation, oxidation, enzymatic modification, graft copolymerization, and the like.

According to an embodiment of the present invention, the composition further comprises other components, including but not limited to at least one of antioxidants, anesthetics, antibacterial agents, DNA fragments, polypeptides, vitamin C, lidocaine, vitamins and amino acids.

According to an embodiment of the present invention, the composition further comprises a solution, and the solution is at least one of an aqueous solution, a physiological saline solution or a phosphate buffer solution.

The present invention also provides uses of the composition, which is used in the fields of medicine, cosmetics, medical cosmetology, tissue repair, and tissue filling.

Specifically, it is used for preparing medicines, cosmetics, medical beauty products, tissue repair agents or tissue fillers.

According to an embodiment of the present invention, the composition is used to prepare a gel; specifically, the gel is used in the fields of medicine, cosmetics, medical cosmetology, tissue repair, and tissue filling.

According to an embodiment of the present invention, the composition can be used alone or in combination with a biologically active compound.

Specifically, the bioactive compound can be selected from vitamin C, retinol, minerals, antioxidant enzymes, lipoic acid, active proteins, etc.

The present invention also provides a gel, wherein the raw materials for preparing the gel are selected from the above-mentioned composition for gel.

According to an embodiment of the present invention, the gel is preferably a hydrogel.

According to an embodiment of the present invention, the gel includes an interpenetrating network structure and a structure based on stereocomplexation; the interpenetrating network structure is formed by hydrophilic PEG segments and hydrophilic polysaccharide segments; the stereocomplexation structure is formed based on the stereocomplexation of PLLA and PDLA, specifically, it is a physical cross-linking point one by one.

According to an embodiment of the present invention, the gel has adjustable mechanical properties; specifically, the elastic modulus of the gel is 10-10 ⁶ Pa.

The present invention also provides a method for preparing the above-mentioned gel, which comprises the following steps:

The gel is prepared by mixing PLLA-PEG, PDLA-PEG and polysaccharide in a solution.

According to an embodiment of the present invention, the solution is at least one of an aqueous solution, a physiological saline solution or a phosphate buffer solution.

According to an embodiment of the present invention, during the mixing process, the hydrophilic PEG segments and the hydrophilic polysaccharide segments form an interpenetrating network structure, and a stereocomplex occurs between the poly-L-lactic acid PLLA segments and the poly-D-lactic acid PDLA segments, and this stereocomplex can be regarded as a physical cross-linking point one by one, thereby forming a gel with mechanical properties. In addition, during the mixing process, there is a hydrogen bond between the polysaccharide segments and the hydrophilic PEG segments (such as hydrogen bond interaction between NH in hyaluronic acid and O in PEG), and this physical interaction makes the gel more stable, stronger in mechanical strength, and less prone to degradation.

The present invention also provides the use of the gel, which is used in the fields of medicine, cosmetics, medical cosmetology, tissue repair and tissue filling.

According to an embodiment of the present invention, the gel is used to prepare medicines, cosmetics, medical cosmetic products (such as fillers), tissue repair agents or tissue fillers (such as tissue scaffolds, etc.).

According to an embodiment of the present invention, the gel may be used alone or in combination with a bioactive compound.

According to an embodiment of the present invention, the gel is used for facial filling. Specifically, the gel is used for preparing facial fillers.

According to an embodiment of the present invention, the gel is used to prepare a medicament for treating eyes.

According to an embodiment of the present invention, the gel is used to prepare a medicament for treating skin disorders or skin blemishes, such as acne, erythema and burns.

According to an embodiment of the present invention, the gel is used to prepare a medicament for treating joint inflammation.

According to an embodiment of the present invention, the gel can be administered by injection, in particular by intradermal, mesodermal, intraarticular or intraocular injection.

According to an embodiment of the present invention, the gel is used as an anti-aging agent or an anti-pollution agent.

According to an embodiment of the present invention, the gel is used for repairing bones, joints, and tissues. Specifically, the gel is used for preparing a repair agent for bones, joints, and tissues.

Beneficial effects of the present invention:

The present invention provides a polysaccharide-polylactic acid gel composition based on stereocomplexation. The polysaccharide-polylactic acid gel composition comprises a first block copolymer, a second block copolymer and a polysaccharide; the first block copolymer comprises a poly-L-lactic acid block and a polyethylene glycol block, and the second block copolymer comprises a poly-D-lactic acid block and a polyethylene glycol block. In the composition, the network structure of the hydrophilic PEG and the network structure of the hydrophilic polysaccharide are interpenetrated, and a stereocomplexation occurs between the poly-L-lactic acid PLLA and the poly-D-lactic acid PDLA. This stereocomplexation can be regarded as a physical cross-linking point one by one, thereby forming a gel with mechanical properties. The preparation method of the gel is simple, and the properties of the obtained gel are adjustable. This gel formed by using the stereocomplexation of polylactic acid as the "cross-linking point" of the gel has many advantages compared with the gel prepared by other cross-linking methods, such as reacting under mild conditions, avoiding the use of catalysts, auxiliary cross-linking agents and other active molecules.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the interaction between gels based on PLLA-PEG, PDLA-PEG and polysaccharides.

DETAILED DESCRIPTION

The present invention will be described in further detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the reagents, materials, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels.

Example 1

Preparation of PLLA-PEG and PDLA-PEG

According to the designed chain length (number of repeating units), dry double-arm PEG (i.e., in formula A, R' is selected from -CH ₂ CH ₂ -, Y is selected from -O-, p=2), L-LA (or D-LA) ₂ (1wt%) are added to a dry reaction bottle, 50 mL of toluene is added, and the mixture is stirred at 120°C for 24 hours. After the reaction is completed, the mixture is filtered after precipitation with ethanol. The mixture is vacuum dried for 48 hours to obtain the product PLLA-PEG or PDLA-PEG.

The number average molecular weight ( _Mn ) and weight average molecular weight ( _Mw ) and molecular weight distribution (PDI = _Mw / _Mn ) of PLLA-PEG and PDLA-PEG were determined by gel permeation chromatography (GPC) with DMF as the mobile phase and monodisperse polystyrene as the standard sample.

The synthesized PLLA-PEG has the following structure:

Wherein, n ₁ , m ₁ , p ₁ are the degree of polymerization.

The synthesized PDLA-PEG has the following structure:

Where n ₂ , m ₂ , and p ₂ are the degrees of polymerization.

Table 1 Composition and performance characterization results of samples Y1 to Y8 prepared in Example 1

Wherein, ^a is the number average molecular weight of PLLA-PEG or PDLA-PEG obtained by calculating the peak integrated area of ¹ H NMR signal; ^b is the number average molecular weight and molecular weight distribution of PLLA-PEG or PDLA-PEG determined by GPC.

In the structural formula, taking PLLA ₅ -PEG ₉₁ -PLLA ₅ as an example, the 5 in PLLA ₅ represents the number of lactic acid repeating units is 5, that is, the corresponding n ₁ and p ₁ are 5; PEG ₉₁ represents the number of ethylene glycol repeating units is 91, that is, the corresponding m ₁ is 91.

Example 2

Preparation of PLLA-PEG and PDLA-PEG

The other aspects are the same as in Example 1, except that a four-arm PEG (i.e., in Formula A, R' is selected from Y is selected from -O-, p=4) to replace the double-arm PEG in Example 1, as shown in Table 2.

Table 2 Composition and performance characterization results of samples Z1 to Z6 prepared in Example 2

Wherein, ^a is the number average molecular weight of PLLA-PEG or PDLA-PEG obtained by calculating the peak integral area of ¹ H NMR signal; ^b is the number average molecular weight and molecular weight distribution of PLLA-PEG or PDLA-PEG determined by GPC. Taking (PEG ₅₇ -PLLA ₅ ) ₄ as an example, 4 means that the number of arms is 4, and PEG ₅₇ -PLLA ₅ means that each arm includes a PEG segment and a PLLA segment, and the number of repeating units of the PEG segment is 57, and the number of repeating units of the PLLA segment is 5.

Example 3

Preparation of hydrogels by mixing PLLA-PEG, PDLA-PEG and hyaluronic acid

Dissolve Y5, Y6 and sodium hyaluronate (HA) in deionized water respectively to completely dissolve them. Mix the dissolved Y5, Y6 and sodium hyaluronate solutions in a predetermined ratio, place them in a 37°C water bath to reach equilibrium, invert the tube, and if there is no flow within 30 seconds, it can be considered that the sample solution has turned into a gel state.

The obtained gel was subjected to rheological tests. The rheological tests were carried out on an Anton Paar MCR 302 rheometer at room temperature. To prevent water evaporation, a lid was placed on the top of the sample. The gap between the rotor and the plate was set to 0.3 mm, the rotor diameter was 25 mm, the temperature was 25 °C, the stress was 1%, and the frequency range was 0.1-10 Hz. G’ refers to the elastic modulus, and G” refers to the viscous modulus. The elastic modulus G’ is used to evaluate the ability of the gel to store energy through elasticity, and the viscous modulus G” is used to evaluate the ability of the gel to dissipate energy through heat. The loss factor Tanδ(G”/G’) is used to evaluate the relative importance of the viscous and elastic behavior of the gel.

The gel samples and properties are shown in the following table:

As can be seen from the above table, when PLLA-PEG and PDLA-PEG exist alone, gel cannot be formed, because PLLA or PDLA alone cannot form cross-linking points. When PLLA-PEG and PDLA-PEG exist at the same time, gel can be formed, indicating that a stereocomplex effect is formed between PLLA and PDLA. Within a certain range, when the mass ratio of Y5, Y6, and HA remains unchanged, the strength of the gel increases with the increase of the total concentration of Y5, Y6, and HA; when the total concentration of Y5, Y6, and HA remains unchanged, the strength of the gel increases with the increase of the mass ratio of Y5+Y6/HA.

Example 4

Preparation of hydrogels by mixing PLLA-PEG, PDLA-PEG and hyaluronic acid

Dissolve Z3, Z4 and sodium hyaluronate (HA) in deionized water respectively to completely dissolve them. The specific implementation steps are the same as those in Example 3.

The gel samples and properties are shown in the following table:

As can be seen from the above table, when PLLA-PEG and PDLA-PEG exist alone, gel cannot be formed, because PLLA or PDLA alone cannot form cross-linking points. When PLLA-PEG and PDLA-PEG exist at the same time, gel can be formed, indicating that a stereocomplex effect is formed between PLLA and PDLA. Within a certain range, when the mass ratio of Z3, Z4, and HA remains unchanged, the strength of the gel increases with the increase of the total concentration of Z3, Z4, and HA.

The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. A composition for gel, wherein the composition comprises a first block copolymer, a second block copolymer and a polysaccharide; the first block copolymer comprises a poly-L-lactic acid block and a polyethylene glycol block, the second block copolymer comprises a poly-D-lactic acid block and a polyethylene glycol block, the first block copolymer is denoted as PLLA-PEG, and the second block copolymer is denoted as PDLA-PEG. 2. The gel composition according to claim 1, wherein the mass ratio of PLLA-PEG to PDLA-PEG in the composition is 0.001-1000:1. Preferably, in the composition, the mass ratio of the sum of the masses of PLLA-PEG and PDLA-PEG to the mass of the polysaccharide is 0.001-1000:1. 3. The composition for gel according to claim 1 or 2, wherein the polyethylene glycol block is derived from a polymer represented by formula A: In formula A, R' is a central molecular group, Y is selected from -O-, -NH-, -C(=O)O- or -OC(=O)-, x is the degree of polymerization, and p is an integer ≥2. Preferably, in formula A, R' is selected from a hydrocarbon group. Preferably, in formula A, R' is selected from alkyl, alkenyl, and aryl. Preferably, p is an integer between 3-16. Preferably, the molecular weight of the PLLA-PEG is 200Da to 7×10 ⁵ Da, and the molecular weight of the PDLA-PEG is 200Da to 7×10 ⁵ Da. Preferably, in the PLLA-PEG, the molecular weight of the PEG block is 50Da to 6×10 ⁵ Da, preferably 1000Da to 4×10 ⁴ Da; the molecular weight of the PLLA block is 100Da to 1×10 ⁵ Da, preferably 800Da to 6000Da. Preferably, in the PDLA-PEG, the molecular weight of the PEG block is 50Da to 6×10 ⁵ Da, preferably 1000Da to 4×10 ⁴ Da; the molecular weight of the PDLA block is 100Da to 1×10 ⁵ Da, preferably 800Da to 6000Da. 4. The gel composition according to any one of claims 1 to 3, wherein the composition further comprises other components, including but not limited to at least one of antioxidants, anesthetics, antibacterial agents, DNA fragments, polypeptides, vitamin C, lidocaine, vitamins and amino acids. Preferably, the composition further comprises a solution, and the solution is at least one of an aqueous solution, a physiological saline solution or a phosphate buffer solution. 5. Use of the gel composition according to any one of claims 1 to 4 for preparing medicines, cosmetics, medical cosmetic products, tissue repair agents or tissue fillers. 6. A gel, wherein the raw material for preparing the gel is selected from the composition for gel according to any one of claims 1 to 4. 7. The gel according to claim 6, wherein the gel comprises an interpenetrating network structure and a structure based on stereocomplexation; the interpenetrating network structure is formed by hydrophilic PEG segments and hydrophilic polysaccharide segments; the stereocomplexation structure is a physical cross-linking point formed one by one based on the stereocomplexation of PLLA and PDLA. 8. A method for preparing the gel according to claim 6 or 7, comprising the following steps: The gel is prepared by mixing PLLA-PEG, PDLA-PEG and polysaccharide in a solution. 9. Use of the gel according to claim 6 or 7 for preparing medicines, cosmetics, medical cosmetic products, tissue repair agents or tissue fillers. 10. The use according to claim 9, wherein the gel is used for preparing medicines, cosmetics, fillers or tissue scaffolds. Preferably, the gel is used to prepare a facial filler; or, the gel is used to prepare a drug for treating the eyes; or, the gel is used to prepare a drug for treating skin disorders or skin blemishes, such as acne, erythema and burns; or, the gel is used to prepare a drug for treating joint inflammation; or, the gel is used for an anti-aging agent or an anti-pollution agent; or, the gel is used to prepare a bone, joint or tissue repair agent.