Self-healing hydrogel with MMPs responsiveness as well as preparation method and application of self-healing hydrogel

Abstract

The invention discloses self-healing hydrogel with MMPs responsiveness and a preparation method and application of the self-healing hydrogel, and relates to the technical field of myocardial tissue repair materials. The hydrogel is prepared by crosslinking a MaPEG (Mapolyethylene glycol)-PLys-PMet antioxidant micelle, a gelatin derivative co-modified by maleimide / 3-amino-4-methoxybenzoic acid, and a dimercapto MMP-2 sensitive polypeptide. The material has excellent mechanical properties, self-repairability, oxidation resistance, mitochondrial protection effect and biocompatibility, and can be used for myocardial injury repair.

Description

Technical Field

[0001] This invention relates to the field of myocardial tissue repair materials technology, and in particular to a self-healing hydrogel with MMP responsiveness, its preparation method and application. Background Technology

[0002] Acute myocardial infarction (AMI) is the leading cause of disability and death in humans, with nearly 40 million people worldwide currently developing heart failure from AMI. Mitochondrial oxidative stress damage and limited proliferation of mature cardiomyocytes after myocardial infarction are the main reasons for impaired myocardial regeneration. Although progress has been made in myocardial regeneration using stem cell and small molecule therapies, the regeneration optimization targeting the infarcted myocardial microenvironment has not been optimized, resulting in poor myocardial repair efficiency. Given the specific location of the infarction and the complexity of the microenvironment, small molecule drug delivery faces challenges such as tissue distribution, affinity, and multiple administrations. Antibody drugs, on the other hand, primarily target membrane surfaces, leaving them ineffective against intracellular targets or even chromosomal nucleic acid targets. Gene therapy, as a treatment method that can achieve long-term and tissue-specific expression of therapeutic proteins, is currently being explored. However, most current gene therapies directly stimulate DNA synthesis or mitosis in mature cardiomyocytes (CMs) by transgenic modification at the infarct site, without optimizing the regeneration targeting the damaged myocardial microenvironment or cells, leading to low CM proliferation efficiency. Therefore, the combination of human heart-specific miR-199a-3p and inhibition of oxidative stress to form a co-delivery system of nucleic acids and antioxidants, which improves mitochondrial function through exogenous intervention of intracellular ROS and promotes cell proliferation by endogenously regulating the gene program of CM proliferation, may be an effective way to achieve myocardial regeneration in adulthood. Summary of the Invention

[0003] One objective of this invention is to provide an amphiphilic MaPEG-PLys-PMet triblock copolymer that can self-assemble in aqueous solution to form micelles with antioxidant properties.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] The structural formula of the MaPEG-PLys-PMet triblock copolymer is as follows:

[0006] .

[0007] On the other hand, the present invention also relates to a method for preparing the above-mentioned MaPEG-PLys-PMet triblock copolymer, the preparation process of which includes the following steps:

[0008] (i) The ring-opening polymerization of Mal-PEG-NH2 and Lys-NCA was carried out to obtain MaPEG-PLys;

[0009] (ii) Further ring-opening polymerization of the MaPEG-PLys and Met-NCA to obtain MaPEG-PLys-PMet.

[0010] In step (ii), after further ring-opening polymerization, the protection can be removed.

[0011] Furthermore, the mass ratio of Mal-PEG-NH2 to Lys-NCA is 100:309. For example, Mal-PEG-NH2 is 100 mg and Lys-NCA is 309 mg.

[0012] Furthermore, the mass ratio of MaPEG-Plys to Met-NCA is 300:340. For example, MaPEG-Plys is 300 mg and Met-NCA is 340 mg.

[0013] This invention also relates to an antioxidant MaPEG-PLys-PMet micelle, which is formed by the self-assembly of the aforementioned MaPEG-PLys-PMet triblock copolymer in an aqueous solution. After entering cardiomyocytes, in a reactive oxygen species (ROS) microenvironment, the hydrophobic thioether groups of the Met side chains are easily oxidized to hydrophilic sulfoxide and sulfone structures, thereby altering the copolymer conformation and endowing it with antioxidant properties; simultaneously, the numerous amino groups on Lys possess the characteristics of loading gene-modifying drugs.

[0014] The MaPEG-PLys-PMet triblock copolymer can self-assemble into antioxidant micelles in an aqueous solution after deprotection treatment.

[0015] Among them, MaPEG-PLys-PMet micelles can be abbreviated as MPG or MPEG.

[0016] The present invention also relates to a self-healing hydrogel with MMP response, which is formed by mixing the following components:

[0017] (a) Antioxidant MaPEG-PLys-PMet micelles as described above;

[0018] (b) A modified gelatin derivative having a gelatin backbone with both maleimide (MA) groups and polymeric side chains composed of 3-amino-4-methoxybenzoic acid (AMB) units.

[0019] (c) MMPs-sensitive peptide crosslinking agent with free thiol groups at both ends.

[0020] Furthermore, the mass ratio of components (a), (b), and (c) is 0.5:50:5, that is, the mass ratio of the antioxidant MaPEG-PLys-PMet micelles, the modified gelatin derivative, and the MMPs-sensitive peptide crosslinking agent is 0.5:50:5. For example, the antioxidant MaPEG-PLys-PMet micelles are 0.5 mg, the modified gelatin derivative is 50 mg, and the MMPs-sensitive peptide crosslinking agent is 5 mg.

[0021] Components (a), (b), and (c) are dissolved in PBS solution and can be gelled at room temperature (25°C) to form the hydrogel; the gelation time is within 60 seconds.

[0022] Each 1 mL of PBS solution contains 0.5 mg of component (a), 50 mg of component (b), and 5 mg of component (c).

[0023] Furthermore, the MMPs-sensitive polypeptide crosslinking agent is a polypeptide with MMP-2 specific cleavable sites and free thiol groups at both ends, and its amino acid sequence is CNGGRMSMPVSC.

[0024] Among them, MMPs-sensitive peptide cross-linking agents can be abbreviated as HS-TIMP-SH, or further abbreviated as TIMP.

[0025] Furthermore, the modified gelatin derivative is prepared by feeding gelatin, 3-maleimide propionic acid and 3-amino-4-methoxybenzoic acid (AMB) in a mass ratio of 250:100:100.

[0026] Among them, the modified gelatin derivative can be abbreviated as PAMB-G-MA, or further abbreviated as PGA.

[0027] The PAMB-G-MA can be prepared by dissolving maleimide-modified gelatin (G-MA) in water, adding 3-amino-4-methoxybenzoic acid (AMB) monomer and ammonium persulfate initiator, and reacting at 40 °C for 24 h to allow AMB to undergo in-situ oxidative polymerization on the gelatin backbone to form poly(3-amino-4-methoxybenzoic acid) (PAMB) branches.

[0028] The route for preparing PAMB-G-MA can be: MA + Celatin → G-MA + PAMB → PAMB-G-MA (the order in which PAMB is added to the reaction does not affect the reaction).

[0029] The self-healing hydrogel with MMP response described above has the following structural formula:

[0030] .

[0031] The aforementioned self-healing hydrogels with MMP response can be used in the preparation of injectable implantable materials for local treatment of myocardial infarction.

[0032] The aforementioned self-healing hydrogels with MMP response can also be used in the preparation of carriers for delivering drugs to treat myocardial injury.

[0033] It is worth noting that natural amino acids and their derivatives (such as L-lysine and L-methionine) as well as naturally derived molecules such as gelatin, have shown unique value in the construction of biomedical polymer materials due to their excellent biocompatibility, biodegradability, ease of chemical functionalization, and the fact that their degradation products can be metabolized by the body and provide energy. They can be used as ideal building blocks for the integration of natural and synthetic materials.

[0034] This invention uses L-methionine (Met) as an antioxidant unit to inhibit mitochondrial oxidative stress damage and L-lysine (Lys) as a gene drug loading carrier. The two amino acids are ring-opened polymerized using the initiator Mal-PEG-NH2, first polymerizing Lys-NCA and then Met-NCA to generate a triblock copolymer (MaPEG-PLys-PMet). Mal-PEG-NH2 is composed of maleimide (Mal), polyethylene glycol (PEG), and an amino group (-NH2). This amphiphilic triblock copolymer can self-assemble into antioxidant micelles in aqueous solution.

[0035] Subsequently, gelatin, one of the cross-linking components of the hydrogel, was modified with an aniline derivative (3-amino-4-methoxybenzoic acid) and maleimide to obtain a modified gelatin derivative (PAMB-G-MA), wherein maleimide serves as the cross-linking site of the hydrogel. This invention also employs a MMP-responsive peptide cross-linking agent (denoted as HS-TIMP-SH, sequence CNGGRMSMPVSC) containing thiol groups at both ends.

[0036] Mixing MaPEG-PLys-PMet micelles, PAMB-G-MA, and HS-TIMP-SH rapidly forms a hydrogel system within 60 seconds at room temperature (25°C). This micelle-hydrogel composite system exhibits excellent mechanical properties and self-healing capabilities, while also demonstrating significant antioxidant capacity, mitochondrial damage mitigation effects, and good biocompatibility and biodegradability. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating the steps involved in preparing the hydrogel in this embodiment;

[0038] Figure 2 The above is the hydrogen spectrum of MaPEG-PLys-PMet micelles in the example;

[0039] Figure 3 The particle size distribution diagram of MaPEG-PLys-PMet micelles in the examples is shown.

[0040] Figure 4 This is a schematic diagram illustrating the stability evaluation of MaPEG-PLys-PMet micelles in the examples;

[0041] Figure 5 The image shown is a transmission electron microscope (TEM) image of MaPEG-PLys-PMet micelles from the example.

[0042] Figure 6 The hydrogen spectrum of the gelatin derivative (PAMB-G-MA) in the examples is shown below;

[0043] Figure 7 The infrared spectrum of the gelatin derivative (PAMB-G-MA) in the examples is shown.

[0044] Figure 8 The image shown is a scanning electron microscope (SEM) image of a hydrogel (control sample) containing only gelatin derivatives and MMPs-sensitive peptide crosslinking agents without MaPEG-PLys-PMet micelles in the examples.

[0045] Figure 9 The image shown is a scanning electron microscope (SEM) image of the hydrogel (executive sample) doped with MaPEG-PLys-PMet micelles and containing gel derivatives and MMPs-sensitive peptide crosslinking agents in the example.

[0046] Figure 10 This is a schematic diagram of the hydrogel rheological test results in the embodiment. Figure 1 ;

[0047] Figure 11 This is a schematic diagram of the hydrogel rheological test results in the embodiment. Figure 2 ;

[0048] Figure 12 This is a schematic diagram illustrating the compressibility of the hydrogel in the embodiment;

[0049] Figure 13 This is a schematic diagram illustrating the injectability of the hydrogel in the embodiments;

[0050] Figure 14 This is a schematic diagram illustrating the self-healing properties of the hydrogel in the embodiment;

[0051] Figure 15 This is a schematic diagram of the hydrogel adhesion performance in the embodiment. Detailed Implementation

[0052] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention. It should be noted in advance that the following embodiments were completed in a laboratory. Those skilled in the art should understand that the amounts of each component given in the embodiments only represent the ratio between the components, and are not specific limitations.

[0053] In summary, the purpose of this invention is to provide an antioxidant micelle-peptide-based hydrogel system with MMP responsiveness, which can be used in the field of myocardial repair. The overall synthetic approach is as follows: an antioxidant MaPEG-PLys-PMet micelle formed by ring-opening polymerization of Lys and Met, gelatin co-modified with conductive-derived 3-amino-4-methoxybenzoic acid (AMB) and maleimide groups (Ma) (PAMB-G-Ma), and an MMP-2 sensitive and cleavable peptide sequence CNGGRMSMPVSC (HS-TIMP-SH) are cross-linked to form a hydrogel.

[0054] One of the preparation steps is to synthesize an antioxidant MaPEG-PLys-PMet micelle. After entering cardiomyocytes, the hydrophobic sulfide end of the Met side chain is easily oxidized to hydrophilic sulfoxide and sulfone structures in the ROS microenvironment, thereby changing the conformation of the copolymer and giving it antioxidant properties. At the same time, the large number of amino groups on Lys have the properties of loading gene drugs.

[0055] The second preparation step involves using the MaPEG-PLys-PMet micelles as the crosslinking core of the hydrogel to crosslink gelatin (after modification) and the MMP-responsive HS-TIMP-SH peptide sequence, ultimately forming a hydrogel system with excellent structure and function.

[0056] The present invention also relates to the medical applications of self-healing hydrogels with MMP responsiveness, for example, by applying them to an environment of overexpressed MMPs in damaged tissue to release related drugs in response; or by applying them to the field of myocardial tissue repair.

[0057] In this invention, a block copolymer is generated by ring-opening polymerization of L-Lys-NCA (i.e., Lys-NCA), L-Met-NCA (i.e., Met-NCA), and the initiator Mal-PEG-NH2. This copolymer can self-assemble in aqueous solution to form antioxidant micelles. The structural formula of this block copolymer is:

[0058] .

[0059] The conductive gelatin PAMB-G-MA involved in this invention provides mechanical support for the myocardial wall in early infarction in terms of structure. Functionally, the gelatin derivative formed by grafting 3-amino-4-methoxy-benzoic acid onto gelatin exhibits good myocardial conductivity, similar to the structure of natural proteins with high water content, and increased self-healing properties. Specifically, gelatin is grafted with both MA and PAMB groups. First, MA is grafted onto gelatin to form a first graft product, and then PAMB is grafted onto the first graft product to form the final gelatin derivative.

[0060] The following detailed examples illustrate these methods. Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; the reagents and raw materials, unless otherwise specified, are commercially available and / or prepared using known methods.

[0061] In this embodiment, MaPEG-PLys-PMet self-assembled micelles and PAMB-G-MA hydrogels were prepared according to the following method. The preparation process can be found in [link to documentation]. Figure 1 .

[0062] 1. Preparation of the first crosslinking product (MaPEG-PLys-PMet self-assembled micelles).

[0063] 1.1 Synthesis of MaPEG-PLys-PMet: Maleimide-based amino polyethylene glycol (Mal-PEG-NH2) and Lys-NCA were ring-opened polymerized to obtain MaPEG-PLys polymer; MaPEG-PLys polymer and Met-NCA were further ring-opened polymerized to obtain MaPEG-PLys-PMet copolymer.

[0064] Specifically as follows:

[0065] S01. Dissolve 100 mg Mal-PEG-NH2 and 309 mg Lys-NCA in 4 mL of anhydrous N,N-dimethylformamide (10 wt%), freeze and thaw three times in liquid nitrogen, stir and react at 35 °C for 72 hours under nitrogen (N2) atmosphere, precipitate multiple times with ice-cold ether, and dry to obtain MaPEG-Plys.

[0066] 300 mg MaPEG-Plys and 340 mg Met-NCA were dissolved in 6 mL of anhydrous N,N-dimethylformamide (10 wt%), and then subjected to three freeze-thaw cycles in liquid nitrogen. After stirring and reacting for 72 hours at 35 °C under a nitrogen (N2) atmosphere, the mixture was precipitated multiple times with ice-cold ether and dried to obtain unprotected MaPEG-PLys-PMet.

[0067] S02. Dissolve 500 mg MaPEG-PLys-PMet in 8 mL of acetic acid solution containing 4 mL of trifluoroacetic acid (5 wt%) and 4 mL of HBr (33 wt%) (i.e., 4 mL of 5 wt% trifluoroacetic acid + 12 mL of 33 wt% HBr acetic acid solution (total 16 mL)). Stir the reaction at 0 °C for 24 hours under a nitrogen (N2) atmosphere. Then precipitate with excess diethyl ether to obtain the crude product. Then dialyze the crude product through a 500 MW dialysis membrane in ammonia water for 3 days to obtain deprotected MaPEG-PLys-PMet.

[0068] 1.2 Self-assembly of MaPEG-PLys-PMet: Deprotected MaPEG-PLys-PMet was dissolved in ultrapure water to prepare a 1 mg / mL solution. The solution was magnetically stirred overnight. After complete dissolution, the solution was sonicated to obtain self-assembled MaPEG-PLys-PMet nanomicelles (i.e., the first cross-linking product).

[0069] 2. Preparation of the second crosslinking product (modified gelatin PAMB-G-MA).

[0070] Using gelatin as a backbone, 3-amino-4-methoxybenzoic acid (AMB) monomer and maleimide group (MA) are modified on it respectively. Then, the monomer (AMB) is polymerized in situ to form PAMB branch chain to obtain a gelatin derivative co-modified with MA and PAMB (PAMB-G-MA).

[0071] Specifically as follows:

[0072] 2.1 Dissolve 3-maleimide propionic acid (100 mg, 0.6 mol) in 1 ml of dichloromethane.

[0073] 2.2 Add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (115.6 mg, 0.6 mmol) and N-hydroxysuccinimide (69.2 mg, 0.6 mmol) to the solution obtained in step 2.1. A white precipitate appears in the solution after stirring for 12 h.

[0074] 2.3 The solution obtained in step 2.2 was washed with 10% citric acid solution, saturated sodium bicarbonate solution, and saturated sodium chloride solution, respectively. After concentration under reduced pressure, a white solid N-hydroxysuccinimide ester of 3-maleimide propionate was obtained (129.4 mg, yield 82%).

[0075] 2.4 Dissolve 250 mg of gelatin in a mixture of 5 mL of water and 4 mL of dimethyl sulfoxide (DMSO) (i.e., the volume ratio of water to DMSO is 5:4, and the total volume of the mixed solution is 9 mL). Dissolve 125 mg of the white solid obtained in step 2.3 in 1 mL of DMSO and add it to the mixed solution. Stir the resulting solution at 40 °C for 24 h.

[0076] 2.5. Dilute the solution obtained in step 2.4 with 10 ml of deionized water and purify it at 40 °C using a 3500 MW dialysis membrane for 5 days, changing the solvent daily. Freeze and lyophilize to obtain G-MA.

[0077] 2.6 Dissolve the G-MA (250 mg) obtained in step 2.5 in 10 ml of deionized water, add 100 mg of 3-amino-4-methoxybenzoic acid (AMB) and 153 mg of ammonium persulfate, and stir at 40 °C for 24 h to obtain a brown solution.

[0078] 2.7. Dilute the brown solution obtained in step 2.6 with 10 ml of deionized water and purify it at 40 °C using a dialysis membrane with a molecular weight of 3500 MW for 5 days, changing the solvent daily. Freeze and lyophilize to obtain the final product PAMB-G-MA.

[0079] 3. Preparation of MMP-sensitive peptide cross-linking agents.

[0080] In this embodiment, a MMP-2 sensitive and cleavable peptide crosslinking agent was selected. Its amino acid sequence is CNGGRMSMPVSC, and both ends are modified with free thiol groups (denoted as HS-TIMP-SH). It was custom-supplied by a peptide synthesis company (obtained through commercial channels).

[0081] 4. Preparation of the target product (hydrogel).

[0082] 50 mg PAMB-G-MA (PGA), 0.5 mg MaPEG-PLys-PMet (MPEG or MPG), and 5 mg HS-TIMP-SH (TIMP) were dissolved in 1 mL of PBS solution. The solution was observed to transform into a gel form within 60 s at room temperature (25°C), thus obtaining a hydrogel.

[0083] Based on the above preparation steps, the hydrogel with the following structural formula was finally prepared:

[0084] .

[0085] The following experiments and analyses were conducted on the products prepared in this embodiment, including structural analysis and performance testing.

[0086] Figure 2-5 The first crosslinking product MaPEG-PLys-PMet (micelles) prepared in this embodiment has a proton NMR spectrum, particle size distribution, stability evaluation, and transmission electron microscopy (TEM) image of the MaPEG-PLys-PMet micelles. The proton NMR spectrum shows that all characteristic peaks of the MaPEG-PLys-PMet structure are present correctly, and the particle size is around 166 nm. The particle size was continuously measured for 7 days, and the particle size was basically stable with no statistically significant difference.

[0087] Figure 6 , 7 The hydrogen and infrared spectra of the second crosslinked product PAMB-G-MA prepared in this embodiment are shown. The 7.0 ppm in the hydrogen spectrum indicates successful grafting of MA, and the 5.3 ppm and 5.7 ppm indicate successful preparation of polyaniline PAMB. The characteristic peaks in the infrared spectrum also prove the successful preparation of the target product.

[0088] Figure 8 , 9 Scanning electron microscopy (SEM) images of two hydrogels (control and experimental samples) prepared according to the method of this embodiment: one without MaPEG-PLys-PMet micelles and the other with MaPEG-PLys-PMet micelles. The results show that the hydrogels have a porous structure, and the cross-section of the hydrogel with MaPEG-PLys-PMet micelles shows cross-linking sites provided by the micelles, resulting in better mechanical properties. The hydrogel without MaPEG-PLys-PMet micelles (control sample) is labeled "5% PGA / 0.5% TIMP". Figure 8 The hydrogel (sample) doped with MaPEG-PLys-PMet micelles was labeled "5% PGA / 0.5% TIMP / 0.05% MPEG, corresponding to..." Figure 9 The percentages (%) in each label represent the concentration.

[0089] Figure 10 , 11 The rheological test results of the hydrogel prepared in this embodiment show that the hydrogel has the characteristics of strong elasticity (solid-like structure), good frequency stability, and structural stability; and the addition ratio of MaPEG-PLys-PMet micelles is the key factor in controlling the mechanical modulus of the hydrogel. Figure 10 , 11In the figure, G' represents the storage modulus, G'' represents the loss modulus, and G' > G'' indicates that the storage modulus is greater than the loss modulus, signifying a hydrogel-like solid structure. This indicates that the hydrogel exhibits dominant elastic behavior in storing and releasing energy during deformation, thus resisting deformation and maintaining its shape. As the concentration of MPEG micelles increases, the storage modulus increases, and the resistance to deformation also strengthens. The percentages (%) of each label in the figure (e.g., G'5%PGA / 0.5%TIMP / 0.06%MPEG, etc.) represent the concentration.

[0090] Figure 12 This is a schematic diagram of the compressibility of the hydrogel prepared in this embodiment. The results show that the hydrogel can withstand more than 90% of the deformation and completely recovers its original morphology after the pressure is removed, indicating its excellent elastic properties. This is mainly due to the fact that the hydrogel is formed by the cross-linking network of abundant Ma groups and -SH through Michael addition reaction.

[0091] Figure 13 This is a schematic diagram of the injectability of the hydrogel prepared in this embodiment. The results show that the hydrogel has good injection compatibility and can be adapted to existing clinically commonly used injection devices. The material does not break or leave any residue during the injection process, and it quickly forms at the target tissue site after injection. It is suitable for various minimally invasive injection scenarios such as subcutaneous and intracavitary injections.

[0092] Figure 14 This is a schematic diagram of the self-healing performance of the hydrogel prepared in this embodiment. The results show that a stretchable hydrogel structure is formed in a short time. This is mainly because there are a large number of polyphenol structures in the hydrogel, which can quickly form a cross-linked gel network through hydrogen bonds, π-π conjugation, etc.

[0093] Figure 15 This is a schematic diagram of the adhesion properties of the hydrogel prepared in this embodiment. The results show that the hydrogel has excellent self-adhesion and can be firmly attached to the surface of wet tissues such as pigskin without the need for external adhesives.

[0094] Based on the above embodiments and analysis and measurement results, a novel MMP-2-responsive hydrogel was obtained by mixing MaPEG-Plys-PMet, PAMB-G-MA, and HS-TIMP-SH as crosslinking monomers. In this hydrogel, HS-TIMP-SH can cleave in response to MMP-2 in the infarct area, thus exhibiting MMP-2 responsiveness. Furthermore, MaPEG-PLys-PMet can be released in response to the infarct area, and MaPEG-PLys-PMet can further cleave intracellularly in response to ROS, leveraging the natural antioxidant capacity of L-Met to achieve anti-inflammatory and antioxidant effects for myocardial repair. The aforementioned MMP-2-responsive hydrogel system exhibits excellent self-healing properties, maintaining contraction-relaxation at the infarct site while preventing the potential consequences of direct drug release. It also possesses advantages such as injectability, excellent biocompatibility, degradability, and simple structural composition, promoting inflammation resolution and myocardial repair, and has broad potential for clinical applications.

[0095] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A MaPEG-PLys-PMet triblock copolymer, characterized in that, The structural formula is: 。 2. The method for preparing the MaPEG-PLys-PMet triblock copolymer according to claim 1, characterized in that, Includes the following steps: The ring-opening polymerization of Mal-PEG-NH2 and Lys-NCA yields MaPEG-PLys; The MaPEG-PLys and Met-NCA were further ring-opened polymerized to obtain MaPEG-PLys-PMet.

3. The method according to claim 2, characterized in that, The mass ratio of Mal-PEG-NH2 to Lys-NCA is 100:

309.

4. The method according to claim 2 or 3, characterized in that, The mass ratio of MaPEG-Plys to Met-NCA is 300:

340.

5. Antioxidant MaPEG-PLys-PMet micelles, characterized in that they are formed by self-assembly of the MaPEG-PLys-PMet triblock copolymer as described in claim 1 in an aqueous solution.

6. A self-healing hydrogel with MMP response, characterized in that, It is formed by mixing the following components: (a) The antioxidant MaPEG-PLys-PMet micelles as described in claim 5; (b) A modified gelatin derivative having a gelatin backbone with maleimide groups and polymeric side chains composed of 3-amino-4-methoxybenzoic acid units; (c) MMPs-sensitive peptide crosslinking agent with free thiol groups at both ends.

7. The self-healing hydrogel with MMP response according to claim 6, characterized in that, The MMPs-sensitive polypeptide crosslinking agent is a polypeptide with MMP-2 specific cleavable sites and free thiol groups at both ends, and its amino acid sequence is CNGGRMSMPVSC.

8. The self-healing hydrogel with MMP response according to claim 6, characterized in that, The gelatin derivative is prepared by feeding gelatin, 3-maleimide propionic acid and 3-amino-4-methoxybenzoic acid in a mass ratio of 250:100:

100.

9. The self-healing hydrogel with MMPs response according to claim 6, characterized in that, The mass ratio of components (a), (b), and (c) is 0.5:50:

5.

10. The use of the MMP-responsive self-healing hydrogel as described in any one of claims 6-9 in the preparation of an injectable implantable material for local treatment of myocardial infarction, or in the preparation of a carrier for delivering a drug for treating myocardial injury.

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