Self-crosslinking gels, polypeptide compositions and methods of making for treating myocardial infarction

Abstract

The application discloses a kind of self-crosslinking gel for treating myocardial infarction, polypeptide composition and preparation method, belong to biological medical material and tissue repair technical field.The application uses polypeptide A and polypeptide B with complementary self-assembly end peptide and oxidation stable end peptide as main material, under the condition of not adding exogenous chemical crosslinking agent, by the first complementary self-assembly end peptide complementary association and collagen triple helix reconfiguration form initial network, then by the second stage of infarction microenvironment oxidation condition induction disulfide bond and di-tyrosine bond growth, realize in situ stabilization, obtain the myocardial repair self-crosslinking gel with injection, retention, biocompatibility and repair activity.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials and tissue repair technology, specifically relating to a self-crosslinking gel, polypeptide composition and preparation method for treating myocardial infarction. Background Technology

[0002] Following myocardial infarction, extensive necrosis of localized cardiomyocytes occurs, the extracellular matrix rapidly degrades, and the ventricular wall thins and progressively dilates, ultimately leading to left ventricular remodeling, decreased ejection fraction, and chronic heart failure. Current drug therapy, stent placement, and reperfusion therapy primarily aim to restore blood flow and slow disease progression, but they are insufficient to directly reconstruct the infarct microenvironment and cannot adequately address issues such as insufficient local mechanical support, persistent inflammation, and inadequate angiogenesis.

[0003] In recent years, injectable hydrogels have been considered an important candidate technology for the treatment of myocardial infarction due to their ability to be delivered to the infarct border area via minimally invasive methods and form a three-dimensional support network in situ. However, existing technologies still have the following common drawbacks: (1) Many myocardial repair hydrogels rely on exogenous chemical crosslinking agents, activators or two-component rapid reaction systems. The preparation process is complicated, the residual risk is high, and the injection window is narrow, which is not conducive to clinical translation.

[0004] (2) Some schemes use recombinant collagen as a loading factor or functional additive instead of as the main collagen-forming network, which results in the biological recognition advantage of collagen not being fully converted into the structural repair advantage of the infarct area.

[0005] (3) Some solutions rely on phenylboronic acid-catechol, NHS activated ester, aldehyde Schiff base or polysaccharide-synthetic polymer covalent crosslinking system. Although they can achieve gelation, their technical routes do not have obvious technical advantages compared with the known technologies in this field.

[0006] (4) Traditional collagen hydrogels are prone to problems such as insufficient gel strength, early dilution and loss, excessive degradation or unstable local retention rate in the dynamic mechanical environment of myocardium, making it difficult to provide continuous support between the inflammatory period and the repair period.

[0007] In addition, the following solutions have also been reported: CN116392633A discloses an injectable hydrogel for treating heart failure based on recombinant humanized collagen. Its main technical route involves a dynamic cross-linking network formed by a functional polymer containing a phenylboronic acid structure and a compound containing a catechol structure, with the recombinant humanized collagen participating as a bioactive component. The limitation of this approach is that its gel-forming core still relies on the added functional polymer and a small-molecule dynamic bond system; the key technical focus is not on the self-cross-linking network formation of the recombinant humanized collagen itself.

[0008] US11497832B2 discloses an injectable hydrogel formed by chemical coupling of recombinant human collagen and chondroitin sulfate via EDC / NHS, for the repair of myocardial infarction. However, the limitation of this approach is that it relies on chemical coupling and cross-linking, involves multiple preparation steps, and the cross-linking is a chemical route.

[0009] CN111588913A discloses a self-crosslinking hyaluronic acid and its composite collagen-based hydrogel injection. The core of this method lies in the Michael addition reaction between thiol groups and double bonds, with the self-crosslinking primarily targeting a modified hyaluronic acid system. However, this approach has limitations: its main network is a modified polysaccharide, and collagen is a compound component.

[0010] The published paper "Delivering More of an Injectable Human Recombinant CollagenIII Hydrogel Does Not Improve Its Therapeutic Efficacy for Treating Myocardial Infarction" (2020) reported the application of recombinant human collagen III-related thermoresponsive hydrogels in myocardial infarction. However, this paper emphasizes the relationship between drug administration timing and efficacy, but does not report whether a self-crosslinking system can be formed based on the complementary self-assembly of the molecular ends of recombinant human collagen and in-situ oxidative stabilization.

[0011] The published paper "Injectable hydrogels with tailored recombinant humanized collagen type I for the repair of damaged hearts by remodeling the myocardial microenvironment" (2025) reported a customized injectable hydrogel loaded with recombinant humanized type I collagen. However, the focus of this approach is on loading recombinant collagen as a therapeutically active component into the injection system, without emphasizing that the main network is composed of recombinant humanized collagen protein and completes a two-stage self-crosslinking through telopeptide complementary pairing and endogenous oxidation conditions.

[0012] Therefore, existing technologies still lack a technical solution that uses recombinant humanized collagen as the main network, does not require exogenous small molecule chemical cross-linking agents, rapidly forms an initial network after injection and further stabilizes it in the infarct microenvironment, while also possessing controllable degradation, good injectability, high local retention rate, and the ability to promote angiogenesis and myocardial repair. Summary of the Invention

[0013] To address the aforementioned shortcomings in existing technologies, this invention provides a self-crosslinking gel, a polypeptide composition, and a preparation method for treating myocardial infarction. This invention uses polypeptides A and B, which have complementary self-assembling terminal peptides and oxidatively stable terminal peptides, as the main materials. Without adding exogenous chemical crosslinking agents, an initial network is formed through complementary association of the first complementary self-assembling terminal peptides and collagen triple helix reconstruction. Then, through a second stage of oxidative conditions in the infarct microenvironment, disulfide bonds and dityrosine bonds are induced to grow, achieving in-situ stabilization and yielding a myocardial repair self-crosslinking gel that combines injectability, retention, biocompatibility, and repair activity.

[0014] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is as follows: The purpose of this invention is to provide a polypeptide composition for preparing a self-crosslinking gel for treating myocardial infarction, comprising complementary crosslinked polypeptide A and polypeptide B; The amino acid sequence of polypeptide A is shown in SEQ ID NO.1, which includes functional domain I, a first complementary self-assembling terminal peptide at one end, and a first oxidatively stable terminal peptide at the other end. The amino acid sequence of polypeptide B is shown in SEQ ID NO.2, which includes functional domain II, a second complementary self-assembly terminal peptide that pairs with and binds to the first complementary self-assembly terminal peptide, and a second oxidatively stable terminal peptide that forms an oxidatively stable crosslinking site together with the first oxidatively stable terminal peptide.

[0015] Furthermore, functional domain I consists of cell adhesion recognition sequence I: GFPGER (SEQ ID NO.3), MMP-responsive degradation sequence I: GPQGIAGQ (SEQ ID NO.4), and bifunctional engineered short peptide I: GARGERGFPGERGVQGPPGPAGAPGTPGPQGIAGQRGVV (SEQ ID NO.5) or GDDGEAGKPGRPGERGPQGIAGQRGVVGLPG (SEQ ID NO.6).

[0016] Furthermore, functional domain II consists of cell adhesion recognition sequence II: GRPGER (SEQ ID NO.7), MMP-responsive degradation sequence II: GIAGIT (SEQ ID NO.8), and bifunctional engineered short peptide: GESGRPGRPGERGLPGPPGIKGAPGPLGIAGITGARGLA (SEQ ID NO.9).

[0017] Furthermore, the first complementary self-assembly terminal peptide and the second complementary self-assembly terminal peptide are coiled-coil peptides (E3 / K3, BASE / ACID, etc.) capable of selective pairing in a neutral aqueous phase, charged complementary peptides (EAK / KAE, E4 / K4, etc.), or complementary short peptides derived from human extracellular matrix proteins (Laminin α / β coiled-coil derived peptide, Laminin β / γ coiled-coil derived peptide, etc.).

[0018] Furthermore, in peptides A and B, AAEAKAK and AKAKAEAE constitute complementary self-assembled terminal peptides, which can promote the directional pairing of the two functional peptides in a neutral aqueous phase by means of charge complementarity.

[0019] Furthermore, the first oxidatively stabilized telopeptide and the second oxidatively stabilized telopeptide each contain one or more cysteine ​​residues and / or one or more tyrosine residues, which are independently selected from one or more of CGYGC (SEQ ID NO.10), CYGGC (SEQ ID NO.11), GYGYC (SEQ ID NO.12), GYGGY (SEQ ID NO.13), and CGGGC (SEQ ID NO.14) to form disulfide bonds and / or dityrosine bonds in dissolved oxygen, peroxides, or local inflammation-related oxidative environments.

[0020] Furthermore, the mass ratio of polypeptide A to polypeptide B is 1:0.6~1.4, and the total concentration is 8~60 mg / mL.

[0021] Another objective of this invention is to provide a method for preparing a self-crosslinking gel for treating myocardial infarction. This method involves peptides A and B in a polypeptide composition forming a first network through complementary self-assembly of terminal peptide pairing and triple helix recovery of functional domains. Subsequently, a second network is formed in the oxidative microenvironment of the infarcted myocardium through cysteine ​​oxidative coupling and / or tyrosine oxidative coupling, resulting in a self-crosslinking gel.

[0022] Furthermore, a buffer solution with a pH of 6.8 to 7.4 was used in the preparation process.

[0023] Furthermore, the buffer solution is a phosphate buffer, HEPES buffer, or an isotonic buffer containing glucose.

[0024] Furthermore, the self-crosslinking gel also includes 0.01~1.5wt% of non-crosslinking auxiliary components.

[0025] Furthermore, the non-crosslinking auxiliary components are selected from hyaluronic acid, chondroitin sulfate, trehalose, mannitol, glutathione, ascorbic acid precursor, SDF-1 mimic peptide, VEGF mimic peptide or combinations thereof; they are only used to regulate osmotic pressure, injection rheology, cell recruitment or early antioxidant microenvironment, and do not serve as the main gelling network.

[0026] Furthermore, the detailed preparation process is as follows: S1. Construct expression vectors encoding polypeptide A and polypeptide B respectively, and express and purify them in eukaryotic or prokaryotic expression systems to obtain polypeptide A and polypeptide B; S2. Dissolve polypeptide A and polypeptide B in cryogenic buffer, and adjust the pH, osmotic pressure and protein concentration to obtain precursor solution A and precursor solution B. S3. Mix precursor solution A and precursor solution B in a preset ratio and defoam at 4-15℃ to obtain an injectable precursor solution. S4. Inject the precursor solution into the myocardium in the infarcted area, the myocardium in the infarct border area, or the transitional area between the two using a syringe. S5. The precursor solution forms an initial gel within 30 seconds to 10 minutes after injection, and further stabilizes within 0.5-24 hours under the influence of the in vivo oxidative microenvironment, forming a self-crosslinking gel implant.

[0027] Another object of the present invention is to provide a self-crosslinking gel for treating myocardial infarction, which is prepared by the above method.

[0028] This invention provides the use of the above-mentioned recombinant collagen self-crosslinking gel in the preparation of injectable formulations for the treatment of myocardial infarction, which includes at least one of the following uses: Improve local mechanical support in the infarct and marginal areas; Improve the retention of local extracellular matrix in the infarct area; Promotes angiogenesis; Reduces the expression of inflammatory factors and cardiomyocyte apoptosis; Reduce left ventricular dilation and adverse remodeling; Increase left ventricular ejection fraction and shorten left ventricular ejection fraction.

[0029] The beneficial effects of this invention are: 1. This invention uses recombinant collagen as the main gelling network, rather than just as a carrier of active substances, thereby making fuller use of the cell recognition and matrix repair advantages of collagen molecules.

[0030] 2. This invention does not rely on exogenous chemical crosslinking agents, phenylboronic acid-catechol dynamic crosslinking systems, or EDC / NHS coupling systems. The technical route is significantly different from existing disclosed solutions and is more conducive to reducing residual risks.

[0031] 3. The present invention adopts a two-stage self-crosslinking mechanism of "rapid physical self-assembly + slow in-situ oxidative stabilization", which not only ensures the clinical injection operation window, but also improves the in-situ retention rate under myocardial pulsation environment.

[0032] 4. This invention introduces an MMP-responsive degradation window into recombinant collagen molecules, making the material degradation rate more compatible with the myocardial repair rhythm after infarction, which is conducive to achieving the dynamic transformation of "support-replacement-remodeling". Attached Figure Description

[0033] Figure 1 This is a schematic diagram illustrating the mechanism by which polypeptide A and polypeptide B form a two-stage self-crosslinking network after mixing. Figure 2 A schematic diagram showing the rheological properties test results of the precursor liquid prepared in Example 1 of this invention; Figure 3 The rheological change curves of the self-crosslinking gel and the oxidative self-assembled gel prepared in Example 1 of the present invention during the gelation process are shown. Figure 4 This is a SEM image of the self-crosslinking gel prepared in Example 1 of the present invention; Figure 5 This is a graph showing the cytotoxicity test results of the self-crosslinking gel prepared in Example 1 of the present invention; Figure 6 This is an echocardiogram of the self-crosslinking gel prepared in Example 1 of the present invention after being used in a rat myocardial infarction model. Figure 7 This is an image showing the HE staining results of the heart after using the self-crosslinking gel prepared in Example 1 of this invention in a rat myocardial infarction model; Figure 8 The image shows the Masoon staining results of the heart after the self-crosslinking gel prepared in Example 1 of this invention was used in a rat myocardial infarction model. Detailed Implementation

[0034] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0035] Example 1 1. Synthesis of amino acids The amino acid sequences of peptide A and peptide B were synthesized by Shanghai Jierui Biotechnology Co., Ltd. The amino acid sequence of peptide A is as follows: CGYGCGGAEAEAKAKGGGARGERGFPGERGVQGPPGPAGAPGTPGPQGIAGQRGVVGGGYGGC (SEQ ID NO. 1).

[0036] The amino acid sequence of polypeptide B is as follows: CYGGCGGAKAKAEAEGGGESGRPGRPGERGLPGPPGIKGAPGPLGIAGITGARGLAGGGYGYC (SEQID NO.2) Among them, GFPGER in peptide A is cell adhesion recognition sequence I, GPQGIAGQ is MMP-responsive degradation sequence I; GARGERGFPGERGVQGPPGPAGAPGTPGPQGIAGQRGVV or GDDGEAGKPGRPGERGPQGIAGQRGVVGLPG is a bifunctional engineered short peptide I.

[0037] In peptide B, GRPGER is cell adhesion recognition sequence II, GIAGIT is MMP-responsive degradation sequence II, and GESGRPGRPGERGLPGPPGIKGAPGPLGIAGITGARGLA is a bifunctional engineered short peptide II.

[0038] Then, secretory expression was performed in the Pichia pastoris system, and peptides A and B were purified by ion exchange and molecular sieve chromatography to obtain peptides with a purity of not less than 90%.

[0039] 2. Preparation of self-crosslinking gels 10 mM peptide A was dissolved in a buffer solution of 10 mmol / L HEPES, 150 mmol / L NaCl, and 2.5 wt% trehalose, and the concentration was adjusted to 20 mg / mL. The pH was adjusted to 7.2 to obtain precursor solution A.

[0040] Dissolve 10 mM peptide B in the same buffer solution, adjust the concentration to 20 mg / mL, and adjust the pH to 7.2 to obtain precursor solution B.

[0041] Precursor solution A and precursor solution B were mixed at a mass ratio of 1:1 and incubated at 4°C with slow inversion for 3 minutes. Vacuum degassing was then performed for 2 minutes to obtain an injectable precursor solution. Injectability was tested using a 29G injection needle; the precursor solution was continuously and uniformly dispensed without visible particles or layering. The precursor solution began to lose its fluidity within 3 minutes at 37°C, and formed an initial gel capable of maintaining its shape within 10 minutes. After 24 hours, the storage modulus was significantly higher than at 10 minutes.

[0042] like Figure 1 As shown, this invention does not adopt the common "external chemical crosslinking agent-driven gelation" route in the prior art. On the one hand, it introduces telopeptides that can rapidly complement each other in the aqueous phase at both ends of the functional domain, so that the material can establish an initial network within minutes after injection. On the other hand, it retains cysteine ​​and / or tyrosine sites in the telopeptides, so that the material can continue to form more stable disulfide bonds and dityrosine bonds in the high reactive oxygen species and local peroxidation environment of the infarct area.

[0043] With the above design, the material initially appears as a flowable precursor solution upon injection, and can still maintain uniform dispersion after being sheared by the needle. After entering the myocardial tissue, the first-stage network is preferentially generated, thereby reducing the diffusion and outflow of the material in the beating myocardium. Then, the second-stage stabilization continues, improving the gel's in-situ retention ability within the 1-4 week repair window.

[0044] Test case 1. Rheological property testing Steady-state shear rheology of the precursor liquid was performed using a rotational rheometer at a constant temperature of 25°C. A cone-plate fixture with a diameter of 20 mm and a cone angle of 1° was selected and calibrated before use. The precursor liquid was allowed to stand at room temperature for 30 min to remove micro-bubbles. An appropriate amount of sample was evenly packed between the fixtures, and any overflow from the edges was scraped off. The sample chamber was sealed to prevent solvent evaporation during the test. A steady-state shear mode was set, with a shear rate scan range of 0.01 s–100 s. A logarithmic uniform sampling method was used to collect the apparent viscosity data of the samples at different shear rates in real time, and viscosity-shear rate rheological curves were plotted. Each group of samples was tested in triplicate. After removing outliers, the average value was taken to analyze the variation of sample viscosity with shear rate and determine the shear thinning properties of the material. The results are shown in [Figure number missing]. Figure 2 .

[0045] like Figure 2 As shown, the precursor fluid of this invention exhibits high viscosity in the low shear rate range, with an initial viscosity of approximately 1030 Pa·s. With increasing shear rate, the viscosity of the precursor fluid decreases significantly, decreasing rapidly in the range of approximately 0.5-10 s⁻¹. When the shear rate continues to increase to above approximately 15-20 s⁻¹, the viscosity decrease becomes more gradual and stabilizes in the range of approximately 923-930 Pa·s. This result indicates that the precursor fluid exhibits typical shear-thinning behavior. The aforementioned shear-thinning characteristics suggest that the precursor fluid can maintain a high viscosity under static or low-disturbance conditions, which is beneficial for maintaining system integrity and local retention. Under external shearing forces such as injection, extrusion, push-in, or spraying, its viscosity can decrease, thereby reducing transport resistance and improving operability and injectability.

[0046] 2. Detection of rheological changes during gel formation of self-crosslinking gels formed solely from the precursor fluid (identified as self-crosslinking gels in the attached figures) and the self-crosslinking gel prepared in Example 1 (identified as oxidative self-crosslinking gels in the attached figures). Dynamic rheological tests of the gelation process were conducted using a rotational rheometer. The test temperature was set to 37℃ (simulating human physiological temperature), and a parallel plate clamp with a diameter of 20 mm and a clamp spacing of 1.0 mm was used. The experiment was divided into two groups: the pure self-crosslinking gel group used the precursor solution of the present invention directly; the oxidative self-crosslinking gel group mixed the precursor solution with a quantitative hydrogen peroxide solution to simulate the in vivo oxidation microenvironment.

[0047] Before testing, the linear viscoelastic range of the system was determined through amplitude scanning experiments. A small-amplitude oscillation time-scan mode with a constant strain of 0.5% and a constant oscillation frequency of 1 Hz was selected, as these parameters do not damage the pre-assembled gel network structure. The sample to be tested was laid flat on the lower plate of the rheometer, the upper plate was adjusted to the set spacing, edge overflow was removed, and the sample tank was sealed. Timing was started from the moment the sample was fully mixed, and continuous dynamic testing was conducted for 60 minutes. The changes in storage modulus G' and loss modulus G'' over time were collected in real time, and modulus-time dynamic rheological curves were plotted. Three parallel replicates were set for each group of samples. After the test, the initial values, rate of change, and stable plateau values ​​of the gel modulus of the two groups were summarized and analyzed to compare the gelation rate, network structure stability, and mechanical properties of simple self-crosslinking and oxidative-assisted self-crosslinking. Throughout the testing process, the evaporation of sample moisture was strictly controlled, and the mass loss of a single sample was controlled within 1%. The relative deviation of the three sets of parallel test data was less than 10%, ensuring the accuracy and validity of the test data. The results are shown in […]. Figure 3 .

[0048] The precursor fluid of this invention, after self-crosslinking and oxidative stabilization, forms a self-crosslinked gel with a three-dimensional network structure, exhibiting significant time-dependent rheological characteristics during gelation. For example... Figure 3 As shown, for the self-crosslinking gel, the storage modulus G' continuously increases with time, gradually rising from approximately 50-60 Pa to approximately 600-650 Pa, while the loss modulus G'' slowly decreases from approximately 170-180 Pa to approximately 125-135 Pa. In the initial stage of gelation, the system exhibits predominantly viscous behavior; as time progresses, G' gradually exceeds G'', indicating a transition from a solution state to an elastically dominated gel state, stabilizing after approximately 10-20 minutes, demonstrating that self-crosslinking can form a relatively stable three-dimensional network structure. Furthermore, hydrogen peroxide was added to simulate oxidative self-crosslinking in vivo. The rheological properties of the oxidative self-crosslinking gel (the self-crosslinking gel prepared in Example 1) are significantly better than those of the simple self-crosslinking gel. Figure 3It is evident that the storage modulus G' of the oxidized self-crosslinking gel increases rapidly within a short period, rising from approximately 90–100 Pa to approximately 1400–1600 Pa, reaching around 1000 Pa in about 5 minutes, and then continuing to increase before plateauing. Simultaneously, its loss modulus G'' remains relatively stable within the range of approximately 210–260 Pa, showing only a slight decreasing trend. These results indicate that under oxidative conditions, in addition to retaining the physical network formed by complementary self-crosslinking, the system further develops a more stable chemical crosslinking structure, thereby significantly improving the gel's elastic response and overall mechanical strength.

[0049] 3. Scanning electron microscopy (SEM) examination Scanning electron microscopy results show that ( Figure 4 The self-crosslinking gel network structure prepared by this invention is relatively dense but still retains a certain amount of porosity, indicating that while maintaining mechanical stability, the system still possesses a microstructural basis conducive to water permeation, nutrient transport, and cell adhesion, migration, and proliferation. For applications such as tissue repair and cell delivery, this interconnected porous structure can provide cells with attachment sites and growth space, and facilitates subsequent tissue ingrowth into the material.

[0050] 4. Cell experiments The in vitro cytotoxicity and biocompatibility of the self-crosslinking gel prepared in this invention were evaluated using cell proliferation assays. Normal cardiomyocytes / mammalian fibroblasts were selected as experimental cells and cultured in a constant temperature and humidity environment using standard complete cell culture medium. The standard culture environment was set at 37 ℃ and CO2 volume fraction of 5%. A blank control group and a material group were set up. The material group was co-cultured with the extract of the self-crosslinking gel prepared in Example 1, while the blank control group was cultured normally in conventional culture medium. The cell seeding density was kept consistent in all groups, and the cells were incubated routinely. The absorbance of cells in each group was measured using the CCK-8 cell viability assay at 24 h, 48 h, and 72 h of cell culture. The cell viability at different culture times was statistically analyzed and calculated. The results are shown in [Figure number missing]. Figure 5 .

[0051] Figure 5 The figure shows the toxicity test results of the self-crosslinking gel (labeled as material group in the figure) prepared in Example 1 of this invention. As can be seen from the figure, as the culture time increased from 24h to 72h, the activity of cells in the material group showed a continuous upward trend, and the cell survival rate at each time point remained at a high level. This indicates that the self-crosslinking gel not only has no cytotoxicity in the early stage, but can also maintain good biocompatibility for a long time, supporting the continuous proliferation and growth of cells.

[0052] 5. Animal experiments An acute myocardial infarction model induced by ligation of the left anterior descending artery was established using SD rats. Within 30 minutes after modeling, the precursor solution obtained in Example 1 was injected into the infarct area and the infarct margin area at multiple points via an open-chest approach, with a total injection volume of 150 μL. A blank control group, a myocardial infarction modeling + equal volume saline injection group (model group), and a self-crosslinking gel group prepared in this invention (labeled as material group in the figure) were set up. Echocardiography was performed 4 weeks after surgery. Figure 6 H&E tissue section staining ( Figure 7 ) and Masoon trichrome staining ( Figure 8 ).

[0053] like Figure 6 , Figure 7 and Figure 8 As shown, the self-crosslinking gel group prepared by this invention is superior to the model group in terms of left ventricular ejection fraction, left ventricular short axis shortening rate, infarct wall thickness and infarct area, and exhibits a lower infarct expansion trend.

[0054] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A polypeptide composition for preparing a self-crosslinking gel for treating myocardial infarction, characterized in that, Including complementary cross-linked peptides A and B; The amino acid sequence of the polypeptide A is shown in SEQ ID NO.1, which includes functional domain I, a first complementary self-assembling terminal peptide at one end, and a first oxidatively stable terminal peptide at the other end. The amino acid sequence of the polypeptide B is shown in SEQ ID NO.2, which includes functional domain II, a second complementary self-assembly terminal peptide that pairs with and binds to the first complementary self-assembly terminal peptide, and a second oxidatively stable terminal peptide that forms an oxidatively stable crosslinking site together with the first oxidatively stable terminal peptide.

2. The polypeptide composition for preparing a self-crosslinking gel for treating myocardial infarction according to claim 1, characterized in that, The mass ratio of polypeptide A to polypeptide B is 1:0.6~1.4, and the total concentration is 8~60 mg / mL.

3. A method for preparing a self-crosslinking gel for treating myocardial infarction, characterized in that, In the polypeptide composition of claim 1, polypeptide A and polypeptide B form a first network through complementary self-assembly of terminal peptide pairing and triple helix recovery of functional domains, and then form a second network in the oxidative microenvironment of the infarcted myocardium through cysteine ​​oxidative coupling and / or tyrosine oxidative coupling, thereby obtaining a self-crosslinking gel.

4. The preparation method according to claim 3, characterized in that, A buffer solution with a pH of 6.8 to 7.4 was also used in the preparation process.

5. The preparation method according to claim 3, characterized in that, The self-crosslinking gel also includes 0.01wt% to 1.5wt% of non-crosslinking auxiliary components.

6. A self-crosslinking gel for treating myocardial infarction, characterized in that, It is prepared by the method described in any one of claims 3 to 5.

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