A dual-responsive hydrogel with three-dimensional topological structure and its synthesis method and use

Abstract

The invention discloses a dual-responsive hydrogel with a three-dimensional topological structure, a synthesis method and a use thereof, and belongs to the technical field of biomedical materials. The invention uses a polymer material containing amino and phenylboronic acid functional groups, a polymer material containing aldehyde and hydroxyl functional groups and a magnetic nanomaterial as basic raw materials, prepares a pH / glucose dual-responsive hydrogel through an in-situ crosslinking reaction and hydrogen bond and charge interaction, and then orients the magnetic nanomaterial in the pH / glucose dual-responsive hydrogel through an external magnetic field to prepare a dual-responsive hydrogel with a three-dimensional topological structure. The hydrogel can encapsulate drugs and cells at the same time, and continuously and controllably release drugs, and the cells are in a good growth state, so the hydrogel is an ideal target hydrogel.

Description

Technical Field

[0001] The invention belongs to the field of biomedical materials, and in particular relates to a dual-responsive hydrogel with a three-dimensional topological structure, a synthesis method and application thereof. Background Art

[0002] The skin is the largest organ in the human body, covering the entire outer surface of the human body and accounting for approximately 8% of the total body mass. It protects the body from injury and microbial infection, and plays a key role in maintaining homeostasis and protecting internal organs from the external environment. According to statistics, hundreds of millions of people suffer skin trauma each year, either intentionally (such as surgery) or unintentionally (such as burns or abrasions). Therefore, the management and treatment of these wounds are of great social and economic significance.

[0003] Under normal circumstances, wound healing can generally be divided into several overlapping stages, including hemostasis, inflammation, proliferation and tissue remodeling. Acute wounds usually go through these stages regularly and eventually heal within a few weeks. However, these stages involve complex and coordinated interactions of multiple growth factors and cell types, and do not always proceed in an orderly manner. Many factors such as diabetes, infection, inflammation and reactive oxygen species (ROS) can affect one of these stages, causing delayed wound healing or turning into chronic wounds. Chronic wounds are susceptible to microbial infection, which triggers persistent inflammation, increases the concentration of ROS and metalloproteinases (MMPs), destroys the extracellular matrix, and seriously hinders wound healing.

[0004] In clinical practice, wound dressings or skin grafts are commonly used to intervene in the healing of various chronic wounds, which is also the most successful strategy at present. Wound dressings can provide a temporary artificial matrix at the wound surface, and can also load drugs, growth factors or cells, etc., to act on different stages of wound healing and promote wound healing. For many years, researchers have been committed to developing various wound dressings and skin substitutes, and have tried to simulate the microenvironment of the wound surface and skin through cutting-edge technologies such as stem cell biology, nanotechnology and various vascularization strategies. The natural wound microenvironment is mainly composed of ECM (extracellular matrix), which contains cell adhesion sites, biochemical signals, growth factors and various cells. ECM is the key to wound healing, which can provide structural support and signals to regulate cell responses. Natural ECM usually has a unique structure, formed by a variety of protein fibers (such as fibrous collagen and elastin), and its characteristic size ranges from tens of nanometers to hundreds of microns. At present, the research on wound dressings mainly focuses on the structural framework of the matrix, focusing on the overall properties of the scaffold material such as mechanics and chemistry, but the topological structure of the scaffold is less considered.

[0005] Studies have shown that the topological structure and characteristic dimensions of the scaffold have a significant impact on cell behavior, which in turn affects the quality of tissue regeneration. For example, the growth direction of cells (such as the arrangement of vascular endothelial cells) is a key factor in controlling the structure and formation of specific tissues; directional polymers and collagen fibers can affect the structure of the extracellular matrix, promote the quiescent keratinocyte phenotype, and prevent scar formation; carbon nanotube arrays can inhibit TGF-β channels, change the composition of the extracellular matrix, inhibit the excessive proliferation of fibroblasts and the expression of collagen, and reduce hypertrophic scars. Therefore, introducing appropriate topological structures and arrays in the design of scaffolds is of great significance for promoting wound healing and developing new wound dressings.

[0006] Most of the topological structures reported in the literature are constructed on a two-dimensional matrix based on a top-down or bottom-up method. The characteristic size of the formed topological pattern is relatively simple, with high directionality and order. However, the characteristic size of natural ECM ranges from tens of nanometers to hundreds of microns, and it does not have such high regularity. In fact, the normal ECM is composed of a non-directionally arranged matrix, while the tumor-related ECM is arranged in an orderly manner, and the cells in the body live in a three-dimensional rather than a two-dimensional microenvironment. Therefore, constructing a topological structure with graded characteristic sizes and non-directional arrangement inside the three-dimensional scaffold rather than on the surface is very important for simulating natural ECM and promoting wound healing. Summary of the invention

[0007] In order to solve the above technical problems, the present invention proposes a dual-responsive hydrogel with a three-dimensional topological structure and a synthesis method and use thereof.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] One of the technical solutions of the present invention: The present invention provides a dual-responsive hydrogel with a three-dimensional topological structure, having a structure as shown in formula (1):

[0010]

[0011] Among them: a is a polymer material containing amino and phenylboronic acid functional groups; b is a polymer material containing aldehyde and hydroxyl groups; c is a topological structure formed by the directional arrangement of magnetic nanomaterials; d is an imine bond (also known as Schiff base), which is generated by the reaction of amino and aldehyde groups and has pH responsiveness; e is a phenylboronic acid ester, which is generated by the reaction of phenylboronic acid and hydroxyl groups and has glucose responsiveness; f is a hydrogen bond, which is formed by the hydroxyl groups on the surface of the magnetic nanomaterial and the amino or hydroxyl groups on the polymer; g is an ionic bond, which is formed by the carboxyl groups on the surface of the magnetic nanomaterial and the amino groups on the polymer.

[0012] The dual-responsive hydrogel with a three-dimensional topological structure of the present invention has a continuous through microporous structure, and its pore size and modulus are adjustable; it has a directional topological structure; it has a dual response capability to pH and glucose; it has injectability and self-healing ability, can encapsulate drug molecules and living cells at the same time, and can continuously and controllably release drug molecules.

[0013] Preferably, the magnetic nanomaterial is a magnetic nanomaterial having hydroxyl and / or carboxyl functional groups on the surface.

[0014] Preferably, the magnetic nanomaterial has hydroxyl and carboxyl functional groups on its surface and is a magnetic nanofiber or a magnetic nanotube.

[0015] Preferably, the polymer material containing amino and phenylboronic acid functional groups is a natural or synthetic polymer material, including any one of phenylboronic acid-modified polylysine, phenylboronic acid-modified chitosan and derivatives thereof.

[0016] Preferably, the polymer material containing aldehyde groups and hydroxyl groups is a natural or synthetic polymer material, including any one of a combination of aldehyde-terminated polyethylene glycol (PEG) and polyvinyl alcohol (PVA), and oxidized dextran.

[0017] A method for synthesizing a dual-responsive hydrogel with a three-dimensional topological structure, using polymer materials containing amino and phenylboronic acid functional groups, polymer materials containing aldehyde and hydroxyl functional groups, and magnetic nanomaterials as basic raw materials, utilizing in-situ crosslinking reaction of Schiff base and phenylboronic acid ester as well as hydrogen bond and charge interaction to prepare a pH / glucose dual-responsive hydrogel, and then orienting the magnetic nanomaterials in the pH / glucose dual-responsive hydrogel through an external magnetic field to prepare a dual-responsive hydrogel with a three-dimensional topological structure.

[0018] Drugs (such as hypoglycemic drugs insulin or antioxidants, etc.) and cells can be loaded in the dual-responsive hydrogel network structure with a three-dimensional topological structure of the present invention; hydrogels with different three-dimensional structures and properties can be prepared by adjusting the molecular weight of the polymer, the ratio of functional groups (amino, phenylboronic acid, aldehyde and hydroxyl) in the polymer, and the content of magnetic nanomaterials.

[0019] The second technical solution of the present invention: a product for guiding cell growth and repairing chronic diabetic wounds, which is made of drugs and the dual-responsive hydrogel with a three-dimensional topological structure.

[0020] The preparation method of the product for guiding cell growth and repairing chronic diabetic wounds comprises the following steps: uniformly mixing a polymer material containing amino and phenylboronic acid functional groups, a polymer material containing aldehyde and hydroxyl functional groups, and a magnetic nanomaterial with hydroxyl and carboxyl functional groups on the surface with a drug, placing the mixture in a magnetic field for orientation, and allowing the mixture to stand to obtain the product for guiding cell growth and repairing chronic diabetic wounds.

[0021] Preferably, the drug comprises one of a pro-inflammatory factor, a hypoglycemic drug, an antioxidant, an anti-inflammatory drug and a cell growth factor.

[0022] Preferably, the product for guiding cell growth and repairing diabetic chronic wounds is a wound dressing.

[0023] The third technical solution of the present invention: the use of the dual-responsive hydrogel with a three-dimensional topological structure in the preparation of products for guiding cell growth and / or repairing diabetic wounds.

[0024] The three-dimensional topological structure in the dual-responsive hydrogel with a three-dimensional topological structure guides cell behavior, regulates cell arrangement and growth direction, and promotes wound healing; at the same time, in the low pH and high blood sugar level microenvironment of diabetic chronic wounds, the imine bonds and phenylboronic acid esters in the hydrogel are partially disconnected, causing the structure of the hydrogel to change, triggering the controlled release of drug molecules at the wound surface, and promoting the healing of chronic wounds; the double network structure between polymer-polymer and polymer-magnetic nanofibers / magnetic nanotubes can improve the mechanical strength of the hydrogel and meet the mechanical performance requirements of the dressing; dynamic bond in situ crosslinking can give the hydrogel injectability and self-healing properties, which is convenient for filling irregular tissue wounds and enables the dressing to maintain structural stability during wound healing.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects:

[0026] (1) The three-dimensional topological dual-responsive hydrogel of the present invention has a three-dimensional topological structure, which can guide cell behavior and regulate cell arrangement and growth direction.

[0027] (2) The three-dimensional topological dual-responsive hydrogel of the present invention has dual responsiveness to pH and glucose.

[0028] (3) The three-dimensional topological dual-responsive hydrogel of the present invention can simultaneously encapsulate drugs and cells, and continuously and controllably release drugs, and the cells grow well.

[0029] (3) The three-dimensional topological dual-responsive hydrogel of the present invention can be used as an active dressing for the repair of diabetic chronic wounds. On the one hand, it can guide cell behavior and regulate cell arrangement and growth direction. On the other hand, it can control the sustained release of drug molecules at the wound surface through pH / glucose dual response, regulate the wound microenvironment, and promote the healing of chronic wounds.

[0030] (4) The three-dimensional topological dual-responsive hydrogel of the present invention is injectable and self-healing.

[0031] (5) The preparation method of the three-dimensional topological dual-responsive hydrogel of the present invention is simple and easy, with mild conditions, and can encapsulate living cells in situ; the micropores and topological structure, modulus, pH / glucose responsiveness and drug release rate of the hydrogel can be adjusted by changing the concentration and ratio of each component, thereby obtaining the desired ideal target hydrogel. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 This is a transmission electron microscope image of the magnetic halloysite nanotubes prepared in Example 1 of the present invention;

[0034] Figure 2 This is a magnetization curve diagram of the magnetic halloysite nanotubes prepared in Example 1 of the present invention;

[0035] Figure 3 This is a scanning electron microscope image of the hydrogel prepared in Example 1 of the present invention;

[0036] Figure 4 The time scanning rheological graph of the hydrogel prepared in Examples 1 and 4 of the present invention;

[0037] Figure 5 This is a drug release curve diagram of the hydrogel prepared in Example 2 of the present invention under different conditions.

[0038] Figure 6 The three-dimensional topological structure in the hydrogel prepared in Example 2 of the present invention, that is, the orientation of the magnetic halloysite tubes in the hydrogel, the left picture is the orientation without magnetic field, the right picture is the orientation in the magnetic field, and the direction of the arrow is the direction of the magnetic field;

[0039] Figure 7 This is a scanning electron microscope image of the hydrogel prepared in Example 3 of the present invention;

[0040] Figure 8 The three-dimensional topological structure in the hydrogel prepared in Example 3 of the present invention, i.e., the orientation of the magnetic halloysite tubes in the hydrogel, the left picture is the orientation without magnetic field, the right picture is the orientation in the magnetic field, and the direction of the arrow is the direction of the magnetic field;

[0041] Fig. 9 The three-dimensional topological structure in the hydrogel prepared in Example 4 of the present invention, that is, the orientation of the magnetic halloysite tubes in the hydrogel, the left picture is the orientation without magnetic field, the right picture is the orientation in the magnetic field, and the direction of the arrow is the direction of the magnetic field;

[0042] Fig.10 This is a drug release curve diagram of the hydrogel prepared in Example 5 of the present invention under different conditions;

[0043] Fig.11 This is a diagram showing the growth of HSF cells in the hydrogel prepared in Example 6 of the present invention. The left picture is the first day, and the right picture is the third day. Green represents live cells, and red represents dead cells.

[0044] Fig.12 This is a growth orientation diagram of HSF in the hydrogel prepared in Example 6 of the present invention. The left picture is without magnetic field orientation, and the right picture is oriented in a magnetic field. The arrow indicates the direction of the magnetic field. The black ones are magnetic nanotubes, and the blue ones are DAPI-stained cell nuclei.

[0045] Fig.13 The three-dimensional topological structure in the hydrogel prepared in Example 7 of the present invention, i.e., the orientation of the magnetic halloysite tubes in the hydrogel, the left picture is the orientation without magnetic field, the right picture is the orientation in the magnetic field, and the direction of the arrow is the direction of the magnetic field;

[0046] Fig.14 This is a diagram showing the growth of HSF cells in the hydrogel prepared in Example 7 of the present invention. The left picture is the first day, and the right picture is the seventh day. Green represents living cells, and red represents dead cells.

[0047] Fig.15 This is a picture showing that the hydrogel prepared in Example 7 of the present invention is used as a wound dressing to promote wound repair. DETAILED DESCRIPTION

[0048] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0049] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0050] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0051] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0052] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0053] The room temperature in the embodiments of the present invention refers to 25±2°C.

[0054] Example 1

[0055] Preparation of phenylboronic acid grafted chitosan / aldehyde-terminated polyethylene glycol / polyvinyl alcohol / magnetic halloysite nanotubes (CSPBA / PEGCHO / PVA / MHNTs) composite hydrogel

[0056] (1) Preparation of phenylboronic acid grafted chitosan (CSPBA)

[0057] 177 mg 3-carboxyphenylboronic acid and 123.3 mg N-hydroxysuccinimide (NHS) were added to a 250 mL round-bottom flask, and 60 mL methanol was added to dissolve. After stirring at room temperature for 20 min, 166.3 mg 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) and chitosan solution (0.5 g dissolved in 60 mL 0.3 wt% acetic acid) were added. After stirring at room temperature for 24 h, the reactants were transferred to a dialysis bag with a molecular weight cutoff of 12 kDa and dialyzed in deionized water for 48 h, with water replaced every 4 hours. The dialyzed sample was freeze-dried to obtain a white powder product, namely CSPBA.

[0058] (2) Preparation of aldehyde-terminated polyethylene glycol (PEGCHO)

[0059] Weigh 6.0g of p-formylbenzoic acid, 8.25g of N, N'-dicyclohexylcarbodiimide (DCC), and 305mg of 4-dimethylaminopyridine (DMAP) into a 250mL round-bottom flask, add 100mL of dichloromethane to mix the reactants evenly, stir in a water bath at 37°C, drop 80mL of dichloromethane solution containing 10g of polyethylene glycol (PEG), and stir at constant temperature for 24h. Filter the reactants to remove the precipitated N, N'-dicyclohexylurea (DCU). After the filtrate is concentrated, it is recrystallized with isopropanol, and the crude product is washed three times with isopropanol and ice ether; after vacuum drying to remove the solvent, wash with water to remove excess DCC, and freeze-dry to obtain a white powder product, which is PEGCHO.

[0060] (3) Preparation of magnetic halloysite nanotubes (MHNTs)

[0061] Weigh 250 mg of halloysite nanotubes and disperse them in 20 mL of deionized water by ultrasonic to obtain a dispersion. Then, add 580 mg of FeCl 3 6H 2 O and 480mg FeSO 4 7H 2 O was added to the above dispersion, the mixed solution was filled with nitrogen, stirred at 60°C for 15 minutes, then 5mL of 25wt% ammonia solution was added, the temperature was raised to 70°C, and the mixed solution was finally reacted for 4 hours. During the reaction, nitrogen was filled throughout the process. MHNTs were separated with the assistance of a magnet and washed with water and ethanol five times until the pH of the solution was neutral. The sample was vacuum dried at 60°C to obtain the final product MHNTs. The transmission electron microscopy image of the prepared magnetic halloysite nanotubes is shown in Figure 1 , the magnetization curve is shown in Figure 2 It can be seen that the prepared magnetic halloysite nanotubes have good paramagnetism.

[0062] (4) Weigh CSPBA, add deionized water to prepare a CSPBA solution with a concentration of 20 mg / mL, adjust the pH value to 7.4, then add a certain amount of insulin, stir to fully dissolve it to obtain a CSPBA / insulin solution (the concentration of insulin in the CSPBA / insulin solution is 6 mg / mL); weigh a certain amount of PVA and PEGCHO, add deionized water to prepare PVA and PEGCHO solutions with a concentration of 16 mg / mL, respectively, adjust the pH value to 7.4, mix the two in equal volumes, and then add a certain amount of MHNTs (the final concentration of MHNTs is 0.54 mg / mL), stirred to disperse evenly, and obtained PVA / PEGCHO / MHNTs dispersion; CSPBA / insulin solution and PVA / PEGCHO / MHNTs dispersion were mixed at a volume ratio of 1:1, and stirred rapidly to mix them evenly. Strong magnets (permanent magnets made of neodymium, iron and boron alloy) were immediately placed at equal distances (4 cm) on both sides of the mixed solution to provide a 0.02 Tesla linear uniform magnetic field environment, and the mixture was allowed to stand for 5 minutes to obtain CSPBA / Oxd / MHNTs composite drug-loaded hydrogel. The scanning electron microscope image of the prepared hydrogel is shown in Figure 3 It can be seen that the prepared hydrogel has a coherent network structure; the time scanning rheological diagram is shown in Figure 4 It can be seen that the hydrogel has a faster gelation speed and better elasticity.

[0063] Example 2 (the preparation method of CSPBA and MHNTs is the same as that of Example 1)

[0064] Preparation of phenylboronic acid grafted chitosan / oxidized dextran / magnetic halloysite nanotubes (CSPBA / Oxd / MHNTs) composite hydrogel

[0065] (1) Preparation of oxidized dextran (Oxd)

[0066] Weigh 1g of dextran and dissolve it in 30mL of water, add 0.597g of sodium periodate (dissolved in 20mL of water), react at room temperature in the dark for 24h, add 0.257g of glycerol, continue stirring for 15min, transfer the reaction mixture to a dialysis bag, dialyze in deionized water for 48h, and change the water every 4 hours. The dialyzed sample is freeze-dried to obtain a white powder product, oxidized dextran (Oxd).

[0067] (2) Weigh a certain amount of CSPBA, add deionized water to prepare a CSPBA solution with a concentration of 20 mg / mL, adjust the pH value to 7.4, then add a certain amount of insulin, stir to fully dissolve it to obtain a CSPBA / insulin solution (the concentration of insulin in the CSPBA / insulin solution is 6 mg / mL; weigh a certain amount of Oxd, add deionized water to prepare an Oxd solution with a concentration of 40 mg / mL, adjust the pH value to 7.4, then add a certain amount of MHNTs (the final concentration of MHNTs is 0.54 mg / mL) g / mL), stirred to disperse evenly, and obtained Oxd / MHNTs dispersion; CSPBA / insulin solution and Oxd / MHNTs dispersion were mixed at a volume ratio of 1:1, and stirred rapidly to mix them evenly. Strong magnets (permanent magnets made of neodymium, iron and boron alloy) were immediately placed at equal distances (4 cm) on both sides of the mixed solution to provide a 0.02 Tesla linear uniform magnetic field environment, and the CSPBA / Oxd / MHNTs composite drug-loaded hydrogel was obtained after standing for 5 minutes. The release curves of hydrogels for insulin under different conditions are shown in Figure 5 It can be seen that insulin can be continuously released in the hydrogel. Lowering the pH value in the release medium or increasing the glucose concentration in the medium can accelerate the release of insulin. It also shows that the hydrogel has pH and glucose responsiveness. The three-dimensional topological structure in the hydrogel, that is, the orientation of the magnetic halloysite tube in the hydrogel, is shown in Figure 6 ,Depend on Figure 6 It can be seen that the magnetic halloysite tubes are oriented along the direction of the magnetic field in the hydrogel to form a topological structure.

[0068] Example 3

[0069] Preparation of phenylboronic acid grafted chitosan / oxidized dextran / magnetic carbon fiber (CSPBA / Oxd / MCTs) composite hydrogel

[0070] (1) Preparation of magnetic carbon fiber

[0071] Divinylbenzene (DVB) was used as monomer, boron trifluoride ether (BF 3 ·O(Et) 2 ) was used as an initiator and a template-free cationic polymerization method was used to prepare polymer nanofibers. The polymer nanofibers were sulfonated with concentrated sulfuric acid and the sulfonated gel layer on the surface was used to adsorb Fe 2+ and Fe 3+ , and then react with urea to control OH - The release rate of the polymer nanofibers loaded with magnetic iron oxide nanoparticles was reduced to 1.5 %. After carbonization at 700°C in nitrogen, magnetic nanocarbon fibers (MCTs) were obtained. The carbon nanofibers can be further functionalized by introducing functional groups such as carboxyl and hydroxyl groups on the surface.

[0072] (2) Weigh 20 mg of CSPBA and dissolve it in 1 mL of deionized water. Stir and dissolve it at room temperature. Adjust the pH value to 7.4 to obtain a CSPBA solution. Add 6 mg of insulin to the CSPBA solution and stir and dissolve it to obtain a mixed solution.

[0073] (3) Weigh 40 mg of Oxd and dissolve it in 1 mL of deionized water, adjust the pH value to 7.4 to obtain an Oxd solution, add 2.4 mg of MCTs to the Oxd solution, and stir to disperse it evenly to obtain an Oxd / MCTs dispersion.

[0074] (4) CSPBA / insulin solution and Oxd / MCTs dispersion were mixed at a volume ratio of 1:1, and stirred rapidly to make them fully mixed. A strong magnet (permanent magnet made of neodymium, iron and boron alloy) was immediately placed at an equal distance (4 cm) on both sides of the mixed solution to provide a 0.02 Tesla linear uniform magnetic field environment. The mixture was allowed to stand for 5 minutes to obtain a CSPBA / Oxd / MCTs composite drug-loaded hydrogel. The scanning electron microscopy image of the prepared hydrogel is shown in Figure 7 , it can be seen that the prepared hydrogel has a coherent network structure. The three-dimensional topological structure in the hydrogel, that is, the orientation of the magnetic halloysite tubes in the hydrogel, is shown in Figure 8 ,Depend on Figure 8 It can be seen that the magnetic halloysite tubes are oriented along the direction of the magnetic field in the hydrogel to form a topological structure.

[0075] Example 4

[0076] (1) Weigh 24 mg of the CSPBA prepared in step (1) of Example 1 and dissolve it in 1 mL of deionized water. Stir and dissolve at room temperature. Adjust the pH to 7.4 to obtain a CSPBA solution.

[0077] (2) Weigh 24 mg of PVA and dissolve it in 1 mL of deionized water. Stir and dissolve at 90° C., then cool to room temperature and adjust the pH value to 7.4 to obtain a PVA solution.

[0078] (3) Weigh 24 mg of the PEGCHO prepared in step (2) of Example 1 and dissolve it in 1 mL of deionized water. Stir and dissolve at room temperature. Adjust the pH to 7.4 to obtain a PEGCHO solution.

[0079] (4) 0.5 mL of PVA solution and 0.5 mL of PEGCHO solution were mixed and stirred to obtain a PVA / PEGCHO mixed solution. 1.44 mg of MHNTs prepared in step (3) of Example 1 were added to the PVA / PEGCHO mixed solution and stirred to disperse them uniformly to obtain a PVA / PEGCHO / MHNTs dispersion.

[0080] (5) The CSPBA solution was mixed with the PVA / PEGCHO / MHNTs dispersion at a volume ratio of 1:1 and stirred rapidly to make them fully mixed. A strong magnet (permanent magnet made of neodymium, iron and boron alloy) was immediately placed at an equal distance (4 cm) on both sides of the mixed solution to provide a 0.02 Tesla linear uniform magnetic field environment. The mixture was allowed to stand for 5 min to obtain a dual-responsive hydrogel with a three-dimensional topological structure. The rheological time scan of the hydrogel was shown in FIG. Figure 4 ,Depend on Figure 4 It can be seen that the hydrogel gels quickly and has good elasticity. The three-dimensional topological structure in the hydrogel, that is, the orientation of the magnetic halloysite tubes in the hydrogel, is shown in Fig. 9 ,Depend on Fig. 9 It can be seen that the magnetic halloysite tubes are oriented along the direction of the magnetic field in the hydrogel to form a topological structure.

[0081] Example 5

[0082] (1) Weigh 30 mg of the CSPBA prepared in step (1) of Example 1 and dissolve it in 1 mL of deionized water. Stir and dissolve it at room temperature. Adjust the pH value to 7.4 to obtain a CSPBA solution. Add 6 mg of insulin to the CSPBA solution and stir and dissolve it at room temperature to obtain a CSPBA / insulin mixed solution.

[0083] (2) Weigh 30 mg of PVA and dissolve it in 1 mL of deionized water. Stir and dissolve at 90° C., then cool to room temperature and adjust the pH value to 7.4 to obtain a PVA solution.

[0084] (3) Weigh 30 mg of the PEGCHO prepared in step (2) of Example 1 and dissolve it in 1 mL of deionized water. Stir and dissolve at room temperature. Adjust the pH to 7.4 to obtain a PEGCHO solution.

[0085] (4) 0.5 mL of PVA solution and 0.5 mL of PEGCHO solution were mixed and stirred evenly. 9 mg of MHNTs prepared in step (3) of Example 1 were added to the PVA / PEGCHO mixed solution and stirred to disperse evenly to obtain a PVA / PEGCHO / MHNTs dispersion.

[0086] (5) The CSPBA solution was mixed with the PVA / PEGCHO / MHNTs dispersion at a volume ratio of 1:1 and stirred rapidly to make them fully mixed. A strong magnet (permanent magnet made of neodymium, iron and boron alloy) was immediately placed at an equal distance (4 cm) on both sides of the mixed solution to provide a 0.02 Tesla linear uniform magnetic field environment. The mixture was allowed to stand for 5 min to obtain a dual-responsive hydrogel with a three-dimensional topological structure loaded with drugs. The release curves of the hydrogel for insulin under different conditions are shown in FIG. Fig.10 It can be seen that insulin can be continuously released in the hydrogel. Lowering the pH value in the release medium or increasing the glucose concentration in the medium can accelerate the release of insulin. This also shows that the hydrogel is pH and glucose responsive.

[0087] Example 6

[0088] (1) Weigh 16 mg of the CSPBA prepared in step (1) of Example 1 and dissolve it in 1 mL of deionized water. Stir and dissolve at room temperature. Adjust the pH to 7.4 to obtain a CSPBA solution. Add HSF cells to the CSPBA solution and gently stir to mix well to obtain a CSPBA / cell mixture.

[0089] (2) Weigh 16 mg of PVA and dissolve it in 1 mL of deionized water. Stir and dissolve at 90° C., then cool to room temperature and adjust the pH to 7.4 to obtain a PVA solution.

[0090] (3) Weigh 16 mg of the PEGCHO prepared in step (2) of Example 1 and dissolve it in 1 mL of deionized water. Stir and dissolve at room temperature. Adjust the pH to 7.4 to obtain a PEGCHO solution.

[0091] (4) 0.5 mL of PVA solution and 0.5 mL of PEGCHO solution were mixed and stirred evenly. 0.96 mg of MHNTs prepared in step (3) of Example 1 were added to the PVA / PEGCHO mixed solution and stirred to disperse evenly to obtain a PVA / PEGCHO / MHNTs dispersion.

[0092] (5) CSPBA solution and PVA / PEGCHO / MHNTs dispersion were mixed at a volume ratio of 1:1, and stirred rapidly to make them fully mixed. Strong magnets (permanent magnets made of neodymium, iron and boron alloy) were immediately placed at equal distances (4 cm) on both sides of the mixed solution to provide a 0.02 Tesla linear uniform magnetic field environment. The mixture was allowed to stand for about 5 minutes to obtain a dual-responsive hydrogel with a three-dimensional topological structure loaded with drugs. The growth of HSF in the hydrogel is shown in Fig.11 It can be seen that the cells grow well in the hydrogel, indicating that the hydrogel has good biocompatibility. The growth orientation of HSF in the hydrogel is shown in Fig.12 , we can see the growth trend of cells along the arrangement direction of magnetic nanotubes (blue is the cell nucleus, black is the magnetic nanotubes), indicating that the topological hydrogel has a guiding effect on the cell growth orientation.

[0093] Example 7

[0094] (1) Dispersing magnetic halloysite nanotubes in PBS (pH 6.0) to obtain a halloysite nanotube dispersion with a concentration of 10 mg / mL; dissolving collagen in PBS (pH 6.0) to obtain a collagen solution with a concentration of 6 mg / mL; mixing the collagen solution and the magnetic halloysite nanotube dispersion, evacuating the mixture at 30°C (vacuum pressure of 5 mm Hg) for 10 h, and then centrifuging the reaction mixture, washing with deionized water, and freeze-drying to obtain collagen-modified magnetic halloysite nanotubes (Col-MHNTs).

[0095] (2) Weigh 16 mg of the CSPBA prepared in step (1) of Example 1 and dissolve it in 1 mL of deionized water. Stir and dissolve at room temperature. Adjust the pH to 7.4 to obtain a CSPBA solution. Add the HSF cells to the CSPBA solution and gently stir to mix well to obtain a CSPBA / cell mixture.

[0096] (3) Weigh 16 mg of PVA and dissolve it in 1 mL of deionized water. Stir and dissolve at 90° C., then cool to room temperature and adjust the pH to 7.4 to obtain a PVA solution.

[0097] (4) Weigh 16 mg of the PEGCHO prepared in step (2) of Example 1 and dissolve it in 1 mL of deionized water. Stir and dissolve at room temperature. Adjust the pH to 7.4 to obtain a PEGCHO solution.

[0098] (5) 0.5 mL of PVA solution and 0.5 mL of PEGCHO solution were mixed and stirred evenly, and 0.96 mg of collagen-modified magnetic halloysite nanotubes were added to the PVA / PEGCHO mixed solution and stirred to make it dispersed evenly to obtain a PVA / PEGCHO / Col-MHNTs dispersion.

[0099] (6) The CSPBA solution was mixed with the PVA / PEGCHO / Col-MHNTs dispersion at a volume ratio of 1:1, and stirred rapidly to make them fully mixed. A strong magnet (permanent magnet made of neodymium, iron and boron alloy) was immediately placed at an equal distance (4 cm) on both sides of the mixed solution to provide a 0.02 Tesla linear uniform magnetic field environment. The mixture was allowed to stand for 5 minutes to obtain a dual-responsive hydrogel with a three-dimensional topological structure loaded with drugs. The three-dimensional topological structure in the hydrogel, i.e., the orientation of the magnetic halloysite tubes in the hydrogel, is shown in FIG. Fig.13 ,Depend on Fig.13 It can be seen that the magnetic halloysite tubes are oriented along the magnetic field direction in the hydrogel to form a topological structure. The growth of HSF in the hydrogel is shown in Fig.14 It can be seen that the cells grow well in the hydrogel (green is live cells, red is dead cells), and the number of cells on the seventh day increased significantly, indicating that the hydrogel has good biocompatibility. Fig.15 Compared with the saline control group, the wound healing rate of the hydrogel dressing-treated mouse group was faster, indicating that the hydrogel can promote the repair of diabetic wounds.

[0100] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A dual-responsive hydrogel with a three-dimensional topological structure, characterized in that: It has the structure shown in formula (1): Among them: a is a polymer material containing amino and phenylboronic acid functional groups; b is a polymer material containing aldehyde and hydroxyl groups; c is a topological structure formed by the oriented arrangement of magnetic nanomaterials; d is an imine bond; e is phenylboronic acid ester; f is a hydrogen bond; g is an ionic bond; The magnetic nanomaterial is a magnetic nanocarbon fiber or a magnetic halloysite nanotube having hydroxyl and / or carboxyl functional groups on the surface; The polymer material containing amino and phenylboronic acid functional groups includes any one of phenylboronic acid-modified polylysine and phenylboronic acid-modified chitosan; The polymer material containing aldehyde groups and hydroxyl groups includes any one of a combination of aldehyde-terminated polyethylene glycol and polyvinyl alcohol, and oxidized dextran; The synthesis method of the dual-responsive hydrogel with a three-dimensional topological structure comprises: using a polymer material containing amino and phenylboronic acid functional groups, a polymer material containing aldehyde and hydroxyl functional groups, and a magnetic nanomaterial as basic raw materials, uniformly mixing to prepare a pH / glucose dual-responsive hydrogel dispersion, immediately orienting the magnetic nanomaterial in the pH / glucose dual-responsive hydrogel dispersion through an external magnetic field, and preparing the dual-responsive hydrogel with a three-dimensional topological structure after standing.

2. A method for synthesizing a dual-responsive hydrogel having a three-dimensional topological structure according to claim 1, characterized in that: A pH / glucose dual-responsive hydrogel dispersion is prepared by uniformly mixing a polymer material containing amino and phenylboronic acid functional groups, a polymer material containing aldehyde and hydroxyl functional groups, and a magnetic nanomaterial as basic raw materials. The magnetic nanomaterial in the pH / glucose dual-responsive hydrogel dispersion is immediately oriented by an external magnetic field, and a dual-responsive hydrogel with a three-dimensional topological structure is prepared after standing.

3. A product for guiding cell growth and repairing chronic diabetic wounds, characterized in that: It is made of drugs and the dual-responsive hydrogel with a three-dimensional topological structure as claimed in claim 1.

4. The product for guiding cell growth and repairing chronic diabetic wounds according to claim 3, characterized in that: The drug comprises one of a pro-inflammatory factor, a hypoglycemic drug, an antioxidant, an anti-inflammatory drug and a cell growth factor.

5. The product for guiding cell growth and repairing chronic diabetic wounds according to claim 3, characterized in that: The product for guiding cell growth and repairing chronic diabetic wounds is a wound dressing.

6. Use of the dual-responsive hydrogel with a three-dimensional topological structure as claimed in claim 1 in the preparation of products for guiding cell growth and / or repairing diabetic wounds.

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