Self-repairing hydrogel based on non-dynamic covalent bonds and application

Abstract

The invention discloses self-repairing hydrogel based on non-dynamic covalent bonds and application, and belongs to the technical field of biological materials. According to the hydrogel, an amido bond is introduced, the efficient and complete self-repairing capacity is achieved, unreacted N-hydroxysuccinimide glutarate (NHS-ester) on a fracture interface is introduced into the hydrogel, the NHS-ester and amino (-NH2) can rapidly form a covalent bond, and initial state repairing can be achieved within a short time without external stimulation. The self-repairing behavior originates from NH2 / NH3 + balance, the NH2 / NH3 + balance maintains the consumption of amino groups in the reaction, and the balance is used as a storage for gradual release of free amino groups, so that covalent bonds are rebuilt for a long time, and the hydrogel has long-term repairing and repeated self-repairing capabilities.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomaterials, and in particular relates to a self-repairing hydrogel based on non-dynamic covalent bonds and applications thereof. Background Art

[0002] Self-healing hydrogels are intelligent materials that can automatically restore their structure and function after external damage. Currently, research on the self-healing properties of hydrogels focuses on dynamic covalent and non-covalent interactions. Dynamic covalent bonds include Diels-Alder, hydrazine, Schiff base, alkoxyamine, and disulfide bonds, while non-covalent interactions include hydrogen bonds, hydrophobic interactions, π-π stacking, metal-ligand coordination, electrostatic interactions, and host-guest recognition. However, there are no reports on the construction of self-healing hydrogel systems based on non-dynamic covalent bonds. This technological gap stems from the contradiction between the inherent structural stability of irreversible covalent bonds and self-healing properties, as traditionally understood.

[0003] Current research on self-healing hydrogels faces limitations such as complex preparation methods, poor mechanical properties, insufficient stability, and unclear self-healing mechanisms. First, the complex preparation methods of most self-healing hydrogels currently available limit their large-scale production and practical applications. Some self-healing hydrogels based on reversible covalent bonds require specific chemical reaction conditions and complex synthesis steps. Second, the mechanical properties of self-healing hydrogels need to be improved. In practical applications, self-healing hydrogels must possess sufficient mechanical strength and toughness to withstand external physical pressure and friction. However, most self-healing hydrogels based on irreversible covalent bonds (such as Schiff base bonds) or non-covalent bonds (such as hydrogen bonds or hydrophobic interactions) easily break down their cross-linked networks when subjected to significant external forces, leading to material failure. Furthermore, the stability of self-healing hydrogels remains an urgent issue. Self-healing hydrogels are often used to encapsulate certain chemical drugs due to their excellent biocompatibility. However, the network structure of hydrogels based on non-covalent bonds is not dense enough, which limits the types of encapsulated substances and makes them incapable of encapsulating sensitive drugs or easily sedimentable particles such as bone powder. This lack of compactness not only affects drug stability and release, but can also lead to partial drug loss during the preparation process. Chemical crosslinkers or crosslinking reaction conditions in the hydrogel can not only lead to drug degradation or inactivation but also create significant gaps, compromising the hydrogel's integrity. Furthermore, the chemical environment of the self-healing hydrogel can affect the stability of sensitive drugs. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a self-healing hydrogel based on non-dynamic covalent bonds and its application to solve the problems in the prior art of low mechanical strength and toughness of self-healing hydrogels, poor stability of self-healing hydrogels, and the possibility that the hydrogels may affect the encapsulated drugs.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The first aspect of the present invention discloses a self-healing hydrogel based on non-dynamic covalent bonds, comprising a first solution and a second solution; the first solution is a mixed solution of an N-hydroxysuccinimide ester polymer and a phosphate buffer solution with a pH value of 4-7, and the second solution is a mixed solution of an amino-containing polymer compound and a phosphate buffer solution with a pH value of 9; When the self-repairing hydrogel is used, the first solution and the second solution are stirred and mixed to form a mixed system, and the system is allowed to stand until it does not flow, thereby obtaining the self-repairing hydrogel.

[0006] A further improvement of the present invention is: Preferably, the N-hydroxysuccinimide ester polymer is any one or more of two-arm polyethylene glycol succinimide glutarate, four-arm polyethylene glycol succinimide glutarate, two-arm polyethylene glycol succinimide succinate, four-arm polyethylene glycol succinimide succinate, polycaprolactone-N-hydroxysuccinimide, polyamidoamine-polyethylene glycol-N-hydroxysuccinimide, polylactic acid-polyethylene glycol-N-hydroxysuccinimide, phenylboronic acid-polyethylene glycol-N-hydroxysuccinimide and polyacrylic acid-N-hydroxysuccinimide ester.

[0007] Preferably, the amino-containing polymer compound is any one or more of gelatin, four-arm polyethylene glycol amino, bovine serum albumin, polyvinylamine, polyamide and polylactic acid.

[0008] Preferably, the volume fraction of the N-hydroxysuccinimide ester polymer in the mixed system is 10%-20%.

[0009] Preferably, the volume fraction of the amino-containing polymer compound in the mixed system is 3% to 20%.

[0010] Preferably, the cross-linking temperature of the first solution and the second solution is room temperature, and the cross-linking time is 3-10 min.

[0011] The second aspect of the present invention discloses an application of the above-mentioned self-repairing hydrogel based on non-dynamic covalent bonds, which is used to wrap sedimentation particles; the wrapping method is: When the first solution and the second solution are mixed, the sedimented particles are added to the mixed system.

[0012] Preferably, the sedimentation particles are one or more of bone powder, nanoceramics, bioglass, etc.

[0013] The third aspect of the present invention discloses an application of the above-mentioned self-repairing hydrogel based on non-dynamic covalent bonds for preparing multilayer hydrogels. The preparation process is as follows: S1, mixing the first solution, the second solution and the first additive, and obtaining the first layer after a cross-linking reaction; S2, mixing the first solution, the second solution, and the second additive on the first layer, and obtaining the second layer after a cross-linking reaction; … Sn, mixing the first solution, the second solution and the nth additive on the n-1th layer, obtaining the nth layer after cross-linking reaction; and preparing the n-layer hydrogel.

[0014] The fourth aspect of the present invention discloses an application of the above-mentioned self-repairing hydrogel based on non-dynamic covalent bonds, which is used to prepare a hollow hydrogel for placing sensitive drugs. The preparation process is as follows: S1, mixing the first solution and the second solution in the upper mold, and preparing a hollow hydrogel upper layer in the upper mold after a cross-linking reaction; S2, placing sensitive drugs in the upper layer of the hollow hydrogel; S3, mixing the first solution and the second solution in the upper mold, inverting the solution onto the upper mold, and preparing a hollow hydrogel lower layer in the lower mold after a cross-linking reaction. After demolding, a hollow hydrogel containing sensitive drugs is obtained.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a self-repairing hydrogel based on non-dynamic covalent bonds. The hydrogel achieves efficient and complete self-repairing ability by introducing amide bonds. The hydrogel introduces unreacted N-hydroxysuccinimide glutarate (NHS-ester) on the fracture interface. NHS-ester can quickly form a covalent bond with amino group (-NH2), and can achieve initial state repair in a short time without external stimulation. This self-repairing behavior is derived from NH2 / NH3 + Balance, the balance is that -NH2 will spontaneously protonate to form NH3 + , and reduce their reactivity. At the same time, in the whole system, there is NH3 + When the reaction is carried out, due to the continuous consumption of NH2, NH2 / NH3 +The balance shifts toward NH2, thereby maintaining the amino groups consumed in the reaction. This balance acts as a reservoir for the gradual release of free amino groups, which can continue to react with NHS-esters to rebuild covalent bonds, giving the hydrogel the ability to repair over the long term and repeatedly self-repair. This repair mechanism is different from traditional hydrogels, combining the high stability of dynamic covalent bond hydrogels and the advantages of easy reconstruction of cross-linking of non-covalent bond hydrogels. In addition, the self-healing properties of the hydrogel provide new strategies for the preparation of various special structure hydrogels, especially in improving interlayer bonding strength and functional integration. Such hydrogels have great application potential in the field of biomedicine, such as sustained drug release and tissue engineering scaffolds. Specifically analyzed, the self-healing hydrogel of the present invention has the following advantages: (1) The amide bond generated by the aminolysis reaction of the non-dynamic covalent bond between N-hydroxysuccinimide ester and amino group can provide the hydrogel with excellent mechanical properties.

[0016] (2) The presence of non-dynamic covalent bonds not only gives the hydrogel the characteristics of covalent bonds but also enables the hydrogel to have good mechanical properties. Therefore, the composite hydrogel constructed in the present invention not only has strong deformation resistance and excellent shape adaptability but also has strong tissue adhesion. The tissue adhesion is obtained due to the reaction between NHS-ester and amino and thiol groups on tissue proteins.

[0017] The present invention discloses an application of a self-healing hydrogel based on non-dynamic covalent bonds for wrapping sedimentation particles. Although physical or chemical interventions may improve the uniformity of bone powder distribution during the gelation process of the hydrogel, they may also destroy the network structure of the hydrogel, thereby affecting its mechanical properties. The non-dynamic covalent bond hydrogel of the present invention has a unique self-healing property, and its network structure is not easily destroyed by easily sedimentation particles. Even if the network is damaged, the protonated amino group can provide -NH2 to form a stable covalent bond with the unreacted NHS-ester, which is conducive to uniform loading of easily sedimentation particles without destroying the network structure of the hydrogel.

[0018] The present invention discloses an application of a self-healing hydrogel based on non-dynamic covalent bonds. Utilizing the self-healing properties of the non-dynamic covalent bond hydrogel of the present invention, a multilayer hydrogel can be prepared by a step-by-step method. The cross-linked interface is dense and free of the "gaps" commonly seen in traditional hydrogels. Compared with traditional multilayer hydrogels, the obtained hydrogel has the significant advantages of overall integrity and no gaps at the joints, thereby ensuring the overall mechanical properties and functions of the material.

[0019] This invention discloses the application of a self-healing hydrogel based on non-dynamic covalent bonds. This method is used to construct hollow hydrogels, leveraging the self-healing ability of non-dynamic covalent bonds (amide bonds). The hydrogels are prepared in a step-by-step manner using a specialized mold. This hollow hydrogel has the potential for controlled release of bioactive molecules, particularly for sensitive agents requiring aqueous environments. This can be extended to stimuli-sensitively anchor drug-loaded devices within body cavities (e.g., after oral administration or minimally invasive implantation in the abdomen, urogenital tract, or vagina). BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The self-repair efficiency of the non-dynamic covalent bond self-repairing hydrogel prepared in Example 1 of the present invention at different repair times.

[0021] Figure 2 This is the cyclic self-repair of the non-dynamic covalent bond self-repairing hydrogel prepared in Example 1 of the present invention at different repair times.

[0022] Figure 3 These are pictures of the torsion and stretching experiments after self-repair of the non-dynamic covalent bond hydrogel prepared in Example 2 of the present invention.

[0023] Figure 4 This is the self-repair efficiency of the non-dynamic covalent bond self-repairing hydrogel prepared in Example 3 of the present invention after 40 minutes of repair.

[0024] Figure 5 The self-repair efficiency of the non-dynamic covalent bond self-repairing hydrogel prepared in Example 3 of the present invention at different repair times.

[0025] Figure 6 This is a picture of tissue adhesion of the non-dynamic covalent self-healing hydrogel prepared in Example 3 of the present invention on the surface of pig skin.

[0026] Figure 7 This is a microscopic image of the self-healing cracks of the non-dynamic covalent bond self-healing hydrogel prepared in Example 6 of the present invention.

[0027] Figure 8 This is a picture of the non-dynamic covalent self-healing hydrogel prepared in Example 7 of the present invention.

[0028] Figure 9 This is a scanning electron microscope image of a cross section of the multilayer hydrogel prepared in Example 7 of the present invention.

[0029] Figure 10 This is a picture of the mold used to prepare the hollow hydrogel in Example 8 of the present invention.

[0030] Figure 11 This is a pressing picture of the hollow hydrogel prepared in Example 8 of the present invention.

[0031] Figure 12 This is a picture of bone powder loading of the non-dynamic covalent self-repairing hydrogel prepared in Example 9 of the present invention.

[0032] (a) The figure shows pictures of non-dynamic covalent self-healing hydrogel and fibrin adhesive in different bone powder loading methods.

[0033] (b) The figure shows the non-dynamic covalent self-repairing hydrogel and fibrin adhesive after being compressed by about 65% under different bone powder loading methods. DETAILED DESCRIPTION

[0034] The present invention is described in further detail below with reference to the accompanying drawings: To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0035] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0036] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0037] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0038] The first aspect of the present invention discloses a self-healing hydrogel with non-dynamic covalent bonds, comprising a first solution and a second solution. A polymer containing N-hydroxysuccinimide ester is dissolved in a phosphate buffer solution with a pH of 4-7 to form the first solution; and an amino-containing polymer compound is dissolved in another phosphate buffer solution with a pH of 9 to form the second solution. The two solutions are slowly mixed at a volume ratio of 1:1 under stirring to ensure full contact and chemical reaction. After mixing, the solution is allowed to stand until it stops flowing, thereby forming a self-healing hydrogel with non-dynamic covalent bonds.

[0039] In some embodiments of the present invention, the N-hydroxysuccinimide ester polymer is any one or more of two-arm polyethylene glycol succinimide glutarate, four-arm polyethylene glycol succinimide glutarate, two-arm polyethylene glycol succinimide succinimide, four-arm polyethylene glycol succinimide succinimide, polycaprolactone-N-hydroxysuccinimide, polyamidoamine-polyethylene glycol-N-hydroxysuccinimide, polylactic acid-polyethylene glycol-N-hydroxysuccinimide, phenylboronic acid-polyethylene glycol-N-hydroxysuccinimide and polyacrylic acid-N-hydroxysuccinimide ester.

[0040] In some embodiments of the present invention, the amino-containing polymer compound is any one or more of gelatin, four-arm polyethylene glycol amino, bovine serum albumin, polyvinylamine, polyamide, and polylactic acid.

[0041] In some embodiments of the present invention, the volume fraction of N-hydroxysuccinimide ester in the first solution is 10%-20%.

[0042] In some embodiments of the present invention, the volume fraction of the amino-containing polymer compound in the second solution is 3% to 20%.

[0043] In some embodiments of the present invention, the volume ratio of the mixed first solution and the second solution is 1:1.

[0044] In some embodiments of the present invention, the gel cross-linking temperature is room temperature and the cross-linking time is 3-10 min.

[0045] In some embodiments of the present invention, the self-healing time is 10-60 min so that the mechanical strength of the healed hydrogel is restored to the original hydrogel strength.

[0046] In a specific embodiment of the present invention, a method for preparing a self-healing hydrogel based on non-dynamic covalent bonds is disclosed. The method comprises dissolving 40 mg of a polymer containing N-hydroxysuccinimide ester in 0.4 mL of a phosphate buffer at a pH of 4-7 to form a first solution containing 10% of the N-hydroxysuccinimide ester polymer by volume. Furthermore, dissolving 12-80 mg of an amino-containing polymer compound in 0.4 mL of a phosphate buffer at a pH of 9 to form a second solution containing the amino-containing polymer compound. The first and second solutions are then mixed uniformly and allowed to stand at room temperature for 3-10 minutes to obtain a self-healing hydrogel based on non-dynamic covalent bonds.

[0047] The second aspect of the present invention discloses an application of a self-repairing hydrogel based on non-dynamic covalent bonds, which is used to wrap sedimentation particles; the wrapping method is: when the first solution and the second solution are mixed, the sedimentation particles are added to the mixed system.

[0048] In some embodiments of the present invention, the sedimentation particles include one or more of bone powder, nanoceramics, bioglass, and attapulgite.

[0049] The third aspect of the present invention discloses a process for preparing a multilayer hydrogel by using the hydrogel prepared by the above method, wherein the preparation process is as follows: S1, mixing the first solution, the second solution and the first additive, and obtaining the first layer after a cross-linking reaction; S2, mixing the first solution, the second solution, and the second additive on the first layer, and obtaining the second layer after a cross-linking reaction; … Sn, mixing the first solution, the second solution and the nth additive on the n-1th layer, obtaining the nth layer after cross-linking reaction; and preparing the n-layer hydrogel.

[0050] The multilayer hydrogel prepared by this method has basically no gaps between layers and has strong mechanical properties. Moreover, since different substances can be added to the multilayer hydrogel, one hydrogel contains multiple materials and has multiple functions.

[0051] Specifically, the additives can be: drug molecules (such as ibuprofen, methotrexate, vitamin C, etc.), growth factors (such as VEGF, PDGF, BMP, etc.), biological macromolecules (such as polypeptides, hyaluronic acid, insulin and calcitonin, etc.), etc.

[0052] The fourth aspect of the present invention discloses a hollow hydrogel prepared by the above-mentioned hydrogel preparation method. The specific preparation process is as follows: Dissolve the N-hydroxysuccinimide ester-containing polymer in 1 mL of phosphate buffer to form a first solution of the N-hydroxysuccinimide ester-containing polymer. Dissolve the amino-containing polymer in another 1 mL of phosphate buffer to form a second solution of the amino-containing polymer. Mix the first and second solutions thoroughly and pour them into the upper mold. Install the mold cover. Wait 3-10 minutes at room temperature before removing the mold cover. The resulting portion forms the upper layer of the hollow hydrogel. At this point, place the sensitive drug-mimicking scaffold within the mold. Dissolve the N-hydroxysuccinimide ester-containing polymer in 0.075 mL of phosphate buffer to form a first solution of the N-hydroxysuccinimide ester-containing polymer. Dissolve the amino-containing polymer in 0.075 mL of phosphate buffer to form a second solution of the amino-containing polymer. Mix the first and second solutions thoroughly and pour them into the lower mold. Place the mold cover upside down onto the upper layer of the hollow hydrogel. Wait 3-10 minutes at room temperature before removing the mold to obtain the hollow hydrogel.

[0053] The following is further explained in conjunction with specific embodiments: Example 1 Double-arm polyethylene glycol succinimidyl glutarate and gelatin are non-dynamic covalent bond hydrogel bases. 40 mg of double-arm polyethylene glycol succinimidyl glutarate was dissolved in 0.4 mL of pH 7 phosphate buffer (volume fraction 10%) to form a first solution of a polymer containing N-hydroxysuccinimide ester; 80 mg of gelatin was dissolved in 0.4 mL of pH 9 phosphate buffer (volume fraction 20%) to form a second solution of an amino polymer compound. The first solution and the second solution were mixed evenly and placed at room temperature for 3 minutes to obtain a self-healing hydrogel based on non-dynamic covalent bonds. Figure 1 As shown in the figure, the non-dynamic covalent bond hydrogel based on double-arm polyethylene glycol succinimidyl glutarate and gelatin can achieve complete self-healing in 10 minutes. Figure 2 This shows that the hydrogel can self-repair multiple times.

[0054] Example 2 Two-arm polyethylene glycol succinimidyl glutarate and four-arm polyethylene glycol amino are non-dynamic covalent bond hydrogel bases. 40 mg of two-arm polyethylene glycol succinimidyl glutarate was dissolved in 0.4 mL of pH 7 phosphate buffer to form a first solution of a polymer containing N-hydroxysuccinimide ester; 40 mg of four-arm polyethylene glycol amino was dissolved in 0.4 mL of pH 9 phosphate buffer to form a second solution of an amino polymer compound. The first solution and the second solution were mixed evenly and placed at room temperature for 3 minutes to obtain a self-healing hydrogel based on non-dynamic covalent bonds. Figure 3As shown, the non-dynamic covalent bond hydrogel based on two-arm polyethylene glycol succinimidyl glutarate and four-arm polyethylene glycol amino can undergo a certain degree of stretching without breaking after self-repair.

[0055] Example 3 Four-arm polyethylene glycol succinimidyl glutarate and four-arm polyethylene glycol amino are non-dynamic covalent bond hydrogel substrates. 40 mg of four-arm polyethylene glycol succinimidyl glutarate was dissolved in 0.4 mL of pH 4 phosphate buffer to form a first solution of a polymer containing N-hydroxysuccinimide ester with a volume fraction of 10%; 40 mg of four-arm polyethylene glycol amino was dissolved in 0.4 mL of pH 9 phosphate buffer to form a second solution of an amino-containing polymer compound with a volume fraction of 10%. The first solution and the second solution were mixed evenly and placed at room temperature for 3 minutes to obtain a self-healing hydrogel based on non-dynamic covalent bonds. Figure 4 As shown in Figure 3, each group of hydrogels showed different self-healing efficiencies after healing at 37°C for 40 min. Figure 5 As shown in Figure 2, a non-dynamic covalent bond hydrogel based on 10% four-arm polyethylene glycol succinimidyl glutarate and 10% four-arm polyethylene glycol amino groups can achieve complete self-repair in 60 minutes. The hydrogel was injected between two pig skins and found to have good tissue adhesion. Figure 6 shown.

[0056] Example 4 Four-arm polyethylene glycol succinimidyl succinate and four-arm polyethylene glycol amino groups serve as the non-dynamic covalent bond hydrogel substrate. 80 mg of four-arm polyethylene glycol succinimidyl succinate was dissolved in 0.4 mL of pH 4 phosphate buffer to form a first solution containing a 20% volume fraction of the N-hydroxysuccinimide ester polymer. 12 mg of four-arm polyethylene glycol amino groups was dissolved in 0.4 mL of pH 9 phosphate buffer to form a second solution containing a 3% volume fraction of the amino-containing polymer. The first and second solutions were mixed thoroughly and allowed to stand at room temperature for 3 minutes to form a self-healing hydrogel based on non-dynamic covalent bonds.

[0057] Example 5 Four-arm polyethylene glycol succinimidyl glutarate and four-arm polyethylene glycol amino groups serve as the non-dynamic covalent bond hydrogel substrate. 60 mg of four-arm polyethylene glycol succinimidyl glutarate was dissolved in 0.4 mL of pH 4 phosphate buffer to form a first solution containing a 15% volume fraction of the N-hydroxysuccinimide ester polymer. 60 mg of four-arm polyethylene glycol amino groups was dissolved in 0.4 mL of pH 9 phosphate buffer to form a second solution containing a 15% volume fraction of the amino-containing polymer. The first and second solutions were mixed thoroughly and allowed to stand at room temperature for 3 minutes to form a self-healing hydrogel based on non-dynamic covalent bonds.

[0058] Example 6 Double-arm polyethylene glycol succinimidyl glutarate and bovine serum albumin are non-dynamic covalent bond hydrogel substrates. 40 mg of double-arm polyethylene glycol succinimidyl glutarate was dissolved in 0.4 mL of pH 7 phosphate buffer to form a first solution of a polymer containing N-hydroxysuccinimide ester; 60 mg of bovine serum albumin was dissolved in 0.4 mL of pH 9 phosphate buffer to form a second solution of an amino polymer compound. The first solution and the second solution were mixed evenly and placed at room temperature for 10 minutes to obtain a self-healing hydrogel based on non-dynamic covalent bonds. Figure 7 As shown, the non-dynamic covalent bond hydrogel based on double-arm polyethylene glycol succinimidyl glutarate and bovine serum albumin has good self-healing ability, and the cracks in the repaired hydrogel are almost invisible.

[0059] Example 7 Take a three-layer hydrogel with two-arm polyethylene glycol succinimidyl glutarate and four-arm polyethylene glycol amino as the non-dynamic covalent bond hydrogel base as an example. The mold used in this example can hold 2.4 mL of solution. 40 mg of two-arm polyethylene glycol succinimidyl glutarate was dissolved in 0.4 mL of pH 7 phosphate buffer to form a first solution of a polymer containing N-hydroxysuccinimide ester; 40 mg of four-arm polyethylene glycol amino was dissolved in 0.4 mL of pH 9 phosphate buffer to form a second solution of an amino polymer compound. The first solution and the second solution were mixed evenly, poured into a mold and left at room temperature for 3 minutes to obtain a self-healing hydrogel layer A based on non-dynamic covalent bonds. Repeat the above steps to prepare a non-dynamic covalent bond hydrogel with two-arm polyethylene glycol succinimidyl glutarate and four-arm polyethylene glycol amino as the base, mix the first solution with the second solution and pour it on top of layer A, wait for 3 minutes at room temperature to form layer B; continue to repeat the above steps, pour the layer C solution obtained by mixing the first solution with the second solution on top of layer B, wait for 3 minutes at room temperature to obtain a three-layer hydrogel with two-arm polyethylene glycol succinimidyl glutarate and four-arm polyethylene glycol amino as the base of the non-dynamic covalent bond hydrogel. The resulting hydrogel is as follows Figure 8 shown. Figure 9 This is a scanning electron microscopy result image, from which it can be observed that there is no visible gap between the hydrogel layers.

[0060] Example 8 Taking the hollow hydrogel with two-arm polyethylene glycol succinimidyl glutarate and four-arm polyethylene glycol amino groups as the non-dynamic covalent bond hydrogel base as an example, the mold used in this embodiment is shown in Figure 10.

[0061] 100 mg of two-arm polyethylene glycol succinimidyl glutarate was dissolved in 1 mL of pH 7 phosphate buffer to form the first solution of the polymer containing N-hydroxysuccinimide esters. 100 mg of four-arm polyethylene glycol amino was dissolved in 1 mL of pH 9 phosphate buffer to form the second solution of the amino-containing polymer. The first and second solutions were mixed thoroughly and poured into the upper mold. The mold lid was then snapped on. After waiting at room temperature for 3 minutes, the mold lid was removed. The resulting portion formed the hollow hydrogel upper layer. The sensitive drug mimetic scaffold was then placed inside. 7.5 mg of two-arm polyethylene glycol succinimidyl glutarate was dissolved in 0.075 mL of pH 7 phosphate buffer to form the first solution of the polymer containing N-hydroxysuccinimide esters. 7.5 mg of four-arm polyethylene glycol amino was dissolved in 0.075 mL of pH 9 phosphate buffer to form the second solution of the amino-containing polymer. Mix the first solution and the second solution evenly, pour them into the lower mold, and then put the upper layer of the hollow hydrogel wrapped in the mold upside down. After waiting for 3 minutes at room temperature, remove the mold to obtain the hollow hydrogel. Figure 11 As shown, the hydrogel has strong sealing properties and mechanical toughness. After pressing, transparent bubbles appear, and the internal sensitive drug mimic stent can be clearly seen. When the force is removed, the hollow hydrogel can still return to its original shape.

[0062] Example 9 Take the hydrogel with two-arm polyethylene glycol succinimidyl glutarate and four-arm polyethylene glycol amino as the non-dynamic covalent bond hydrogel base as an example.

[0063] 50 mg of two-arm polyethylene glycol succinimidyl glutarate was weighed and dissolved in 0.5 mL of pH 7 phosphate buffer to form a first solution of the polymer containing N-hydroxysuccinimide ester. 50 mg of four-arm polyethylene glycol amino was dissolved in 0.4 mL of pH 9 phosphate buffer to form a second solution of the amino polymer compound. The first and second solutions were mixed thoroughly and allowed to stand at room temperature for 3 minutes to obtain a bone powder-free self-healing hydrogel based on non-dynamic covalent bonds.

[0064] 50 mg of two-arm polyethylene glycol succinimidyl glutarate was dissolved in 0.5 mL of pH 7 phosphate buffer to form a first solution of the polymer containing N-hydroxysuccinimide ester. 50 mg of four-arm polyethylene glycol amino was dissolved in 0.4 mL of pH 9 phosphate buffer to form a second solution of the amino polymer. The first and second solutions were mixed thoroughly, and 10 mg of bone powder particles were added to the mixed solution. The solution was then left at room temperature for 3 minutes to form a self-healing hydrogel with non-dynamic covalent bonds and bone powder sedimentation.

[0065] 50 mg of two-arm polyethylene glycol succinimidyl glutarate was dissolved in 0.5 mL of pH 7 phosphate buffer to form a first solution of a polymer containing N-hydroxysuccinimide esters. 50 mg of four-arm polyethylene glycol amino was dissolved in 0.4 mL of pH 9 phosphate buffer to form a second solution of an amino-containing polymer. The first and second solutions were mixed thoroughly, and 10 mg of bone powder particles were added to the mixed solution. The mixture was shaken for 3 minutes to thoroughly mix, resulting in a self-healing hydrogel with uniform bone powder and non-dynamic covalent bonds.

[0066] Figure 12 (a) is the comparative experimental result of fibrin adhesive under the same operation. Figure 12 (b) After compression to approximately 65%, the non-dynamic covalent bond hydrogel maintains mechanical stability, while the presence of bone powder in the fibrin adhesive disrupts the hydrogel network, resulting in a decrease in mechanical properties. Furthermore, this uniform bone powder preparation method makes the fibrin adhesive hydrogel prone to bubble formation. [The remaining text appears to be unrelated and should likely be omitted.]

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A self-repairing hydrogel based on non-dynamic covalent bonds, characterized in that: The invention comprises a first solution and a second solution; the first solution is a mixed solution of an N-hydroxysuccinimide ester polymer and a phosphate buffer solution with a pH value of 4-7, and the second solution is a mixed solution of an amino-containing polymer compound and a phosphate buffer solution with a pH value of 9; When the self-repairing hydrogel is used, the first solution and the second solution are stirred and mixed to form a mixed system, and the system is allowed to stand until it does not flow, thereby obtaining the self-repairing hydrogel.

2. The self-repairing hydrogel based on non-dynamic covalent bonds according to claim 1, characterized in that: The N-hydroxysuccinimide ester polymer is any one or more of two-arm polyethylene glycol succinimide glutarate, four-arm polyethylene glycol succinimide glutarate, two-arm polyethylene glycol succinimide succinate, four-arm polyethylene glycol succinimide succinate, polycaprolactone-N-hydroxysuccinimide, polyamidoamine-polyethylene glycol-N-hydroxysuccinimide, polylactic acid-polyethylene glycol-N-hydroxysuccinimide, phenylboronic acid-polyethylene glycol-N-hydroxysuccinimide and polyacrylic acid-N-hydroxysuccinimide ester.

3. The self-repairing hydrogel based on non-dynamic covalent bonds according to claim 1, characterized in that: The amino-containing polymer compound is any one or more of gelatin, four-arm polyethylene glycol amino, bovine serum albumin, polyvinylamine, polyamide and polylactic acid.

4. The self-repairing hydrogel based on non-dynamic covalent bonds according to claim 1, characterized in that: The volume fraction of the N-hydroxysuccinimide ester polymer in the mixed system is 10%-20%.

5. The self-repairing hydrogel based on non-dynamic covalent bonds according to claim 1, characterized in that: The volume fraction of the amino-containing polymer compound in the mixed system is 3% to 20%.

6. The self-repairing hydrogel based on non-dynamic covalent bonds according to claim 1, characterized in that: The cross-linking temperature of the first solution and the second solution is room temperature, and the cross-linking time is 3-10 min.

7. An application of the self-repairing hydrogel based on non-dynamic covalent bonds according to claim 1, characterized in that: Used to wrap sediment particles; the wrapping method is: When the first solution and the second solution are mixed, the sedimented particles are added to the mixed system.

8. The use of the self-repairing hydrogel based on non-dynamic covalent bonds according to claim 7, characterized in that: The sedimentation particles are one or more of bone powder, nano-ceramics, bioglass, etc.

9. An application of the self-repairing hydrogel based on non-dynamic covalent bonds according to claim 1, characterized in that: For preparing multilayer hydrogel, the preparation process is as follows: S1, mixing the first solution, the second solution and the first additive, and obtaining the first layer after a cross-linking reaction; S2, mixing the first solution, the second solution, and the second additive on the first layer, and obtaining the second layer after a cross-linking reaction; … Sn, mixing the first solution, the second solution and the nth additive on the n-1th layer, and obtaining the nth layer after a cross-linking reaction; An n-layer hydrogel was prepared.

10. An application of the self-repairing hydrogel based on non-dynamic covalent bonds according to claim 1, characterized in that: It is used to prepare hollow hydrogels for placing sensitive drugs. The preparation process is as follows: S1, mixing the first solution and the second solution in the upper mold, and preparing a hollow hydrogel upper layer in the upper mold after a cross-linking reaction; S2, placing sensitive drugs in the upper layer of the hollow hydrogel; S3, mixing the first solution and the second solution in the upper mold, inverting the solution onto the upper mold, and preparing a hollow hydrogel lower layer in the lower mold after a cross-linking reaction. After demolding, a hollow hydrogel containing sensitive drugs is obtained.

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