Self-healing high-strength injectable hydrogel and preparation method and application thereof

Abstract

The present application relates to the field of biomaterials, and particularly relates to a self-repairing high-strength injectable hydrogel and a preparation method and application thereof.The preparation method of the self-repairing high-strength injectable hydrogel comprises mixing and reacting dopamine-modified silver-doped nano-hydroxyapatite, an o-diphenol chitosan solution and a four-arm alkyl PEG to obtain the injectable hydrogel.The method can prepare the injectable hydrogel with high mechanical properties, and the hydrogel has good self-repairing performance and high-strength performance, so that the hydrogel has a wide application prospect in the field of biomedical materials, and can be applied in the stress strengthening of aortic blood vessels.

Description

Technical Field

[0001] This invention relates to the field of biomaterials, and more particularly to a self-healing, high-strength injectable hydrogel, its preparation method, and its applications. Background Technology

[0002] Aortic dilatation is a serious vascular disease that threatens human life, most commonly found in the aorta below the renal artery. Essentially, it is caused by the arterial wall's inability to withstand the pressure of blood flow within the lumen, leading to segmental dilation and eventual rupture. Crucial factors include inflammatory cell infiltration, loss of vascular smooth muscle cells, and degradation of the extracellular matrix, resulting in an imbalance in the structure and load of the tunica media. Current treatments for abdominal aortic aneurysms include drug therapy, open surgical resection, and endovascular surgery. However, there are currently no effective drugs or interventions to inhibit the progression of abdominal aortic aneurysms. Furthermore, surgical treatment is high-risk and expensive, and patients with abdominal aortic aneurysms are generally older and often suffer from conditions such as hypertension and hyperlipidemia, resulting in poor surgical tolerance. Therefore, exploring safe and effective techniques for treating abdominal aortic aneurysms is of paramount importance.

[0003] In recent years, the emergence of tissue engineering technology has brought new solutions for tissue repair and reconstruction. Tissue engineering achieves wound repair and functional recovery by constructing tissue and organ substitutes in vitro or in vivo, mainly including three basic elements: biological scaffold materials, seed cells, and growth factors. An ideal biological scaffold material not only needs good biosafety and biocompatibility, but also a three-dimensional porous structure to provide space for the transport of oxygen and nutrients, provide appropriate mechanical support, and be clinically operable. However, currently, the biological scaffold materials used for abdominal aortic aneurysms mainly use composites of metal materials and artificial vascular membranes. This type of material is not only expensive, but its plasticity and biocompatibility are also greatly limited, making it prone to forming gaps with tissues and leading to later detachment. Novel hydrogel materials have attracted much attention due to their unique biological and physicochemical properties (such as cell compatibility, high water retention, permeability, and adjustable mechanical properties), and their ability to fill wounds of any shape. Currently, there is an urgent need to develop a self-healing, high-strength injectable hydrogel with broad application prospects in the biomedical field (such as aortic vascular stress reinforcement). Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a self-healing, high-strength injectable hydrogel, its preparation method, and its applications.

[0005] According to the present invention, the implantation of traditional abdominal aortic aneurysm stent materials involves replacing the aneurysm by cutting off the aneurysm site or covering it from inside the artery. This method is prone to dislodgement or slippage in the later stages, leading to complications. The interstitial structure is a multi-level network located between cells, functional tissues, and organs throughout the body. At the nanoscale, the network is composed of fibers arranged in a tightly connected tissue. At the macroscale, the interstitial structure (fascia) envelops blood vessels, forming the perivascular interstitial space. This interstitial structure has the functions of connection, filling, fixation, and nutrient transport. The hydrogel of the present invention is amorphous, injectable, and also possesses self-healing properties and high mechanical properties. Injecting the hydrogel into the intersheath space of the abdominal aorta via intersheath injection can enhance the compressive strength of the blood vessel. In this invention, by injecting the injectable hydrogel into the perivascular space through this extravascular interstitial structure, the blood vessel's resistance to the impact of arterial blood flow is enhanced, thereby protecting the arteries and inhibiting the progression of aortic dilatation diseases.

[0006] Firstly, the present invention provides a method for preparing a self-healing, high-strength injectable hydrogel, comprising mixing dopamine-modified silver-doped nano-hydroxyapatite, catechol-based chitosan solution, and four-armed sulfhydryl PEG, and performing a cross-linking reaction to obtain an injectable hydrogel. The preparation method provided by the present invention yields an injectable hydrogel with high mechanical properties, exhibiting excellent self-healing and high strength properties, making it promising for broad applications in the biomedical field. The self-healing, high-strength injectable hydrogel provided by the present invention can be applied to strengthen aortic vascular stress. The hydrogel prepared using dopamine-modified silver-doped nano-hydroxyapatite (HA-Ag / PDA), catechol-based chitosan (CS-C), and four-armed sulfhydryl PEG (four-armed PEG-SH) is injected into the interthelial space of the abdominal aorta via interthelial injection, thereby strengthening the blood vessel's resistance to blood flow impact and inhibiting the progression of aortic dilatation diseases.

[0007] Preferably, the preparation method of the self-healing high-strength injectable hydrogel includes the following steps:

[0008] 1) Mix CaNO3·4H2O, EDTA·2Na, AgNO3 and (NH4)2HPO4, adjust the pH, and carry out a hydrothermal reaction to obtain silver-doped nano-hydroxyapatite (HAP-Ag);

[0009] 2) Chitosan, HCl solution and dihydrocaffeic acid (HCA) are mixed to obtain a mixed solution; an alcoholic solution of EDC and NHS is prepared and preferably added dropwise to the mixed solution, stirred and the pH is maintained for reaction; dialyzed and dried to obtain o-diphenol chitosan (CS-C);

[0010] 3) Use dopamine hydrochloride (C8H) 12 The silver-doped nano-hydroxyapatite (HAP-Ag) was modified with ClNO2 to obtain dopamine-modified silver-doped nano-hydroxyapatite. Then, the dopamine-modified silver-doped nano-hydroxyapatite was mixed with a solution of tetra-arm sulfhydryl PEG (tetra-arm PEG-SH) and ortho-diphenolic chitosan (CS-C) to obtain an injectable hydrogel.

[0011] This invention utilizes a hydrothermal method to prepare silver-doped nano-hydroxyapatite, which not only forms cross-linking sites with catechol-based chitosan but also endows the hydrogel with certain antibacterial properties. Furthermore, dopamine modification of the silver-doped nano-hydroxyapatite significantly improves its dispersibility in solution, ensuring its uniform distribution within the gel system. The catechol groups in the molecule, after oxidation, can also cross-link with the sulfhydryl groups in PEG, further enhancing the mechanical strength of the hydrogel. The presence of the catechol groups also provides the gel with strong tissue repair properties, ensuring its reliability and safety. This invention prepares a self-healing, high-strength injectable hydrogel that can be applied to strengthen aortic vascular stress. The hydrogel is prepared using dopamine-modified silver-doped nano-hydroxyapatite (HA-Ag / PDA), catechol-based chitosan (CS-C), and four-armed sulfhydryl PEG (four-armed PEG-SH). The hydrogel is injected into the intersheath space of the abdominal aorta via intersheath injection to enhance the vessel's resistance to blood flow impact and inhibit the progression of aortic dilatation diseases. In this invention, the hydrogel is used via intersheath injection into the intersheath space of the abdominal aorta to enhance the vessel's resistance to blood flow impact at the aneurysm site, thereby inhibiting the occurrence and development of aortic dilatation diseases. The prepared hydrogel and its application method can provide new ideas for the treatment of related diseases.

[0012] Preferably, in step 1), the mass concentration of CaNO3·4H2O is 50–55 mg / mL; and / or, the mass concentration of EDTA·2Na is 16–20 mg / mL; and / or, the mass concentration of AgNO3 is 1–3 mg / mL; and / or, the mass concentration of (NH4)2HPO4 is 18–21 mg / mL; and / or, the pH is adjusted by ammonia, preferably 8–11.

[0013] Further preferred, the mass concentrations of CaNO3·4H2O, EDTA·2Na, AgNO3, and (NH4)2HPO4 are 53.2±0.5 mg / mL, 18.6±0.5 mg / mL, 2±0.5 mg / mL, and 19.8±0.5 mg / mL, respectively, and the pH is 10. Preferably, the hydrothermal reaction is followed by freeze-drying.

[0014] Preferably, in step 1), the silver-doped nano-hydroxyapatite is in the shape of a solid rod; preferably, the length is 190-210 nm and the diameter is 25-35 nm.

[0015] The silver-doped nano-hydroxyapatite prepared by the hydrothermal method of the present invention can not only form cross-linking sites with o-diphenol chitosan, but also give the hydrogel certain antibacterial properties.

[0016] Preferably, in step 2), the chitosan has a mass concentration of 8–15 mg / mL, the HCl solution has a pH of 3–8, and the HCA has a mass concentration of 210–225 mg / mL.

[0017] Further preferably, the chitosan has a mass concentration of 10 mg / mL, the HCl solution has a pH of 5, and the HCA has a mass concentration of 218.6 mg / mL.

[0018] Preferably, in step 2), the mass concentration of EDC is 20–25 mg / mL; and / or the mass concentration of NHS is 12–15 mg / mL; and / or a 50%–55% ethanol solution is used; and / or the reaction is carried out by stirring at room temperature for 8–12 hours and maintaining pH 5–6.

[0019] In this invention, experimental research has shown that when the material is prepared using a preferred mass concentration, the yield of the material can be improved, the grafting rate of chitosan can reach 11.5%, and it can exhibit better adhesion and self-healing properties, so that the mechanical properties of the prepared hydrogel can reach the optimal level.

[0020] Further preferably, in step 2), the dialysis method involves dialysis in NaCl solution for 1 to 3 days and dialysis in water for 0.5 to 1 day; the molecular weight cutoff of the dialysis bag is preferably 12,000 to 14,000 D.

[0021] Further preferably, in step 2), the drying is carried out by freeze drying.

[0022] Preferably, in step 3), the C8H 12 The mass concentrations of ClNO2, HAP-Ag, and PEG-SH are 1–3 mg / mL, 20–30 mg / mL, 80–120 mg / mL, and CS-C are 18–25 mg / mL.

[0023] Further preferred, the C8H 12 The mass concentrations of ClNO2, HAP-Ag, four-arm PEG-SH, and CS-C were 2 mg / mL, 25 mg / mL, 100 mg / mL, and 20 mg / mL, respectively.

[0024] Further preferred, in step 3), the dopamine-modified silver-doped nano-hydroxyapatite is mixed with the four-armed PEG-SH and CS-C solutions and vortexed for 8-12 min, and reacted for 22-26 h.

[0025] Secondly, the self-healing high-strength injectable hydrogel provided by the present invention is obtained by the preparation method of the self-healing high-strength injectable hydrogel.

[0026] Thirdly, the self-healing high-strength injectable hydrogel prepared by the method described in this invention is used in drug delivery for the treatment of aortic vascular diseases.

[0027] According to the present invention, the enhancement of the blood vessel's resistance to blood flow impact is achieved by applying pressure to the blood vessel using a pressure pump, followed by pressure detection and statistical analysis using a pressure sensor. In this invention, the prepared hydrogel is injected into the interthelial space of the abdominal aorta via interthelial injection, thereby enhancing the blood vessel's resistance to blood flow impact.

[0028] According to the embodiments provided by the present invention, the method for preparing a self-healing high-strength injectable hydrogel / preparing a drug for use in strengthening aortic vascular stress includes the following steps:

[0029] 1) Calcium nitrate tetrahydrate (CaNO3·4H2O), disodium ethylenediaminetetraacetate (EDTA·2Na), silver nitrate (AgNO3) and diammonium hydrogen phosphate (NH4)2HPO4) were mixed, and after adjusting the pH with ammonia water, a hydrothermal reaction was carried out. After freeze-drying, silver-doped nano-hydroxyapatite (HAP-Ag) was obtained.

[0030] 2) Chitosan was dissolved in HCl solution and miscible with dihydrocaffeic acid (HCA) solution. Simultaneously, a mixed solution of EDC and NHS in water and ethanol was prepared. This solution was then added dropwise to the mixed solution, and the mixture was stirred vigorously at room temperature for 10 hours, maintaining a specific pH for the reaction. After the reaction was complete, the solution was dialyzed in NaCl solution and water, and then lyophilized to obtain CS-C powder.

[0031] 3) Utilizing dopamine hydrochloride (C8H) 12 HAP-Ag was modified with ClNO2, then mixed with a four-arm PEG-SH and CS-C solution and vortexed for 10 minutes and reacted for 24 hours to obtain an injectable hydrogel.

[0032] 4) The injectable hydrogel is injected into the interthelial space of the abdominal aorta via interthelial injection. This invention enhances the blood vessel's resistance to blood flow shock.

[0033] The beneficial effects of this invention are at least as follows:

[0034] 1) This invention prepares an injectable hydrogel with high mechanical properties, excellent self-healing properties, and high strength, making it a promising candidate for application in the biomedical field.

[0035] 2) This invention provides a method of injecting hydrogel into the interthelial space of the abdominal aorta via interthelial injection to enhance the compressive strength of the artery. Attached Figure Description

[0036] To more clearly illustrate the embodiments of the present invention and the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart of the preparation and interthelial injection of a strong mechanically capable injectable hydrogel according to Embodiment 1 of the present invention;

[0038] Figure 2 These are scanning electron microscope and transmission electron microscope images of silver-doped nano-hydroxyapatite from Example 1 of this invention;

[0039] Figure 3 This is a physical illustration of the injectable properties of the hydrogel from Embodiment 1 of the present invention;

[0040] Figure 4 This is an image of the hydrogel in Embodiment 1 of the present invention undergoing self-repair after being cut;

[0041] Figure 5 These are illustrations of the hydrogel injected into the adventitia of the abdominal aorta according to Embodiment 1 of the present invention, and images after HE staining.

[0042] Figure 6 This is a statistical chart of the burst pressure of the abdominal aorta before and after hydrogel injection in Embodiment 1 of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0044] Unless otherwise stated, all raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods. Where specific techniques or conditions are not specified in the examples, they are performed using conventional methods or in accordance with techniques or conditions described in the literature in this field, or according to the product instructions. Reagents and instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0045] The present invention will be further described below with reference to embodiments.

[0046] Example 1

[0047] This embodiment provides a method for preparing a self-healing, high-strength injectable hydrogel and its application in strengthening aortic vessel stress, comprising the following steps:

[0048] First, 2.66 g (11.25 mmol) of calcium nitrate tetrahydrate (CaNO3·4H2O), 0.93 g (2.50 mmol) of disodium ethylenediaminetetraacetate (EDTA·2Na), and 0.1 g of silver nitrate (AgNO3) were weighed and dissolved in 2.5 ml of trihydrate, and stirred for 30 min. Then, 0.99 g (7.5 mmol) of diammonium hydrogen phosphate ((NH4)2HPO4) was weighed and dissolved in 25 ml of trihydrate, stirred for 30 min, and then added dropwise to the above solution. After mixing, the pH of the solution was adjusted to 10 with ammonia water, and the solution was placed in a 60°C water bath and stirred for 60 min (stirring speed: 300 rpm). The solution was then transferred to a reaction vessel and reacted at 180°C for 12 h. After cooling to room temperature, the solution was washed three times with anhydrous ethanol and deionized water, filtered, and freeze-dried to obtain HAP-Ag powder. 504.2 mg of chitosan was dissolved in HCl solvent at pH 5. Then, 546.5 mg of HCA was dissolved in 5 mL of triterpenoid water and mixed with the chitosan solution. 575.1 mg of EDC and 345.3 mg of NHS were dissolved in 50% ethanol solution and added dropwise to the above mixture. The mixture was stirred vigorously at room temperature for 10 h, maintaining the pH at approximately 5. After the reaction was complete, the solution was dialyzed in 10 mM NaCl solution for 2 days, followed by dialyzed in water for 0.5 days, and then freeze-dried to obtain CS-C powder. 25 mg of HAP-Ag and 2 mg of dopamine hydrochloride were dissolved in 1 mL of triterpenoid water and stirred thoroughly. Then, 100 mg of tetra-arm PEG-SH (molecular weight: 20000) and 20 mg of CS-C were added to each 1 mL of solution, vortexed, and transferred to a mold. The mixture was allowed to gel at room temperature for 24 h. Experimental rats were anesthetized and fixed on a worktable. After preparing the skin, a midline abdominal incision was made. Upon entering the abdomen, the intestines were wrapped with warm, moist gauze to the left side. The peritoneum was cut anterior to the abdominal aorta, revealing the abdominal aorta approximately 2 cm below the level of the renal artery and above the level of the iliac artery. A 24-gauge indwelling needle was inserted into the aorta through the right iliac artery, with the other end connected to a pressure pump and gauge. A 0.5 to 1 cm wide space was then exposed above the iliac artery bifurcation, and the wound was covered with gauze soaked in 30 U / mL elastase for 30 minutes. The indwelling needle was then inserted into the treated mid-segment of the abdominal aorta, and both ends were ligated to secure it. The pressure pump was then adjusted to 1 mL / min, and pressure was continuously applied to the vessel until it ruptured and saline leaked out; the burst pressure was recorded at this point. The mouse abdominal aorta was then treated in the same manner, and 200 μL of hydrogel was injected into the space between the adventitia of the abdominal aorta, 0.5 cm above the iliac artery. The burst pressure of the aorta was then tested and recorded.

[0049] Figure 1 This is a flowchart of the preparation and interthelial injection of injectable hydrogels with strong mechanical properties; Figure 2These are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of silver-doped nano-hydroxyapatite. As can be seen from the images, the silver-doped nano-hydroxyapatite is a solid rod-shaped particle with a length of about 200 nm and a diameter of about 30 nm. Figure 3 This is a physical demonstration of the injectability of hydrogel. As you can see, hydrogel has good injectability and can be patterned. Figure 4 The image shows a hydrogel that self-heals after being cut. As can be seen from the image, when the two cut surfaces of the hydrogel are placed together, it can self-heal and will not break even when stretched. Figure 5 These are illustrations of hydrogel injected into the adventitia of the abdominal aorta and images after HE staining. As can be seen from the images, after the hydrogel is injected into the adventitia of the aorta via the intersheath space, it can effectively encapsulate the blood vessel and achieve a protective effect. Figure 6 This is a statistical chart of the burst pressure of the abdominal aorta before and after hydrogel injection. As can be seen from the chart, the burst pressure of the aorta is greatly enhanced after hydrogel injection, which provides a possibility for inhibiting the development and rupture of aortic dilatation diseases and opens up new ideas.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for the preparation of a self-healing high-strength injectable hydrogel for aortic vascular stress augmentation, characterized by, Comprising the following steps: 1) mixing calcium nitrate tetrahydrate, EDTA 2Na, AgNO3 and (NH4)2HPO4, adjusting pH, and performing hydrothermal reaction to obtain silver-doped nano-hydroxyapatite; in step 1), the silver-doped nano-hydroxyapatite is in the shape of solid rod, with a length of 190-210 nm and a diameter of 25-35 nm; 2) mixing chitosan, HCl solution and dihydrocaffeic acid HCA to obtain a mixed solution; preparing an alcohol solution of EDC and NHS and adding the solution to the mixed solution, maintaining pH and performing reaction; dialysis, drying, and obtaining o-diphenol chitosan; in step 2), the mass concentration of chitosan is 8-15 mg / mL, the mass concentration of HCA is 210-225 mg / mL, the mass concentration of EDC is 20-25 mg / mL, and the mass concentration of NHS is 12-15 mg / mL; 3) using dopamine hydrochloride C8H 12 ClNO2 is used to modify the silver-doped nano-hydroxyapatite HAP-Ag to obtain dopamine-modified silver-doped nano-hydroxyapatite, and then the dopamine-modified silver-doped nano-hydroxyapatite is mixed with a solution of four-arm thiol PEG and the ortho-diphenol chitosan CS-C to obtain an injectable hydrogel.

2. The method for preparing the self-healing high-strength injectable hydrogel according to claim 1, characterized in that, In step 1), the mass concentration of calcium nitrate tetrahydrate is 50-55 mg / mL; and / or, the mass concentration of EDTA 2Na is 16-20 mg / mL; and / or, the mass concentration of AgNO3 is 1-3 mg / mL; and / or, the mass concentration of (NH4)2HPO4 is 18-21 mg / mL; and / or, the pH is adjusted by ammonia water.

3. The method for preparing the self-healing high-strength injectable hydrogel according to claim 2, characterized in that, In step 1), the pH is adjusted by ammonia water to 8-11.

4. The method of claim 1, wherein the self-healing high-strength injectable hydrogel is prepared by the steps of: In step 2), the pH of the HCl solution is 3-8.

5. The method for preparing the self-healing high-strength injectable hydrogel according to claim 1, characterized in that, In step 2), 50%-55% ethanol solution is used; and / or, stirring at room temperature for 8-12 h, and maintaining pH 5-6 for reaction; and / or, the dialysis method is dialysis in NaCl solution for 1-3 days and dialysis in water for 0.5-1 day.

6. The method of claim 1, wherein the self-healing high-strength injectable hydrogel is prepared by the steps of: In step 2), the molecular weight cut-off of the dialysis bag is 12000-14000D.

7. The method of claim 1-6, wherein the self-healing high-strength injectable hydrogel is prepared by, In step 3), the C8H 12 The mass concentration of ClNO2 is 1-3 mg / mL; the mass concentration of HAP-Ag is 20-30 mg / mL; the mass concentration of four-arm thiol PEG is 80-120 mg / mL; and the mass concentration of CS-C is 18-25 mg / mL.

8. The method of claim 7, wherein the self-healing high-strength injectable hydrogel is prepared by the steps of: In step 3), the dopamine-modified silver-doped nano-hydroxyapatite is mixed with four-arm thiol-PEG and CS-C solution and vortexed for 8-12 min, and the reaction is performed for 22-26 h.

9. A self-healing high-strength injectable hydrogel for aortic vascular stress augmentation, characterized in that, The self-repairing high-strength injectable hydrogel prepared by the method of any one of claims 1-8.

10. Use of a self-repairing high-strength injectable hydrogel prepared according to the process of any one of claims 1 to 8, characterized in that, Use in preparing aortic vascular stress strengthening drugs.

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