Drug-loaded self-repairing hydrogel as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of biological materials, and particularly relates to drug-loaded self-repairing hydrogel as well as a preparation method and application thereof. According to the composite hydrogel, graphene oxide and a medicine are dispersed in a hydrogel matrix material, the hydrogel matrix material is prepared from agarose and gelatin, and the mass ratio of the medicine to the graphene oxide to the agarose to the gelatin is (0.001 to 0.1) to (0.005 to 0.05) to (0.5 to 4) to (5 to 40). The hydrogel disclosed by the invention has the advantages of easiness in preparation, safety, simplicity, convenience, shape and the like, so that the hydrogel is suitable for various wound surfaces with different shapes. Animal experiments show that the composite hydrogel has an obvious effect of promoting the healing of a full-thickness skin wound of a rat. The composite hydrogel dressing disclosed by the invention has a good application prospect in the aspect of skin wound healing.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomaterials, and in particular relates to a drug-loaded self-repairing hydrogel and a preparation method and application thereof. Background Art

[0002] As the body's first line of defense against the outside world, the integrity and function of the skin are crucial to maintaining health. When the skin is damaged, various wounds, such as burns and trauma, form. Skin wound healing is a complex process involving four phases: hemostasis, inflammation, proliferation, and remodeling. These phases are meticulously regulated by a variety of cells and biological mediators. Numerous cell growth factors play a crucial role in this process. Therefore, the addition of growth factors to skin injuries has the potential to promote rapid wound recovery.

[0003] As a biomaterial, hydrogels have demonstrated tremendous potential in the field of skin wound repair in recent years. They can mimic the skin's natural environment, providing a moist, suitable healing environment for wounds, promoting cell proliferation and migration, and thus accelerating wound healing. In particular, self-healing hydrogels can rebuild their networks and restore their original shape after rupture through dynamic non-covalent interactions between molecular, oligomer, or polymer chains. This allows them to continuously cover the wound, protect it from infection, and release drugs. Agar and gelatin, currently recognized as hydrogels with excellent biocompatibility and biodegradability, inherently undergo gel-to-sol phase transitions with increasing temperature and sol-to-gel phase transitions with decreasing temperature. Combining these two materials could potentially create temperature-responsive self-healing hydrogels that can achieve controlled drug release after loading.

[0004] Graphene oxide is a two-dimensional material with excellent biocompatibility and photothermal conversion efficiency. Incorporating graphene oxide into hydrogels can impart excellent photothermal conversion capabilities. When exposed to near-infrared light, the graphene oxide-doped hydrogels can alter their physicochemical properties through the photothermal conversion effect, thereby altering drug release kinetics.

[0005] Therefore, a hydrogel drug delivery system that can effectively deliver cell growth factors is expected. Summary of the Invention

[0006] The purpose of the present invention is to provide a drug-loaded self-repairing hydrogel and its preparation method and application, so as to be used for the preparation of a hydrogel with good biocompatibility, self-repair ability and controlled release ability.

[0007] To this end, the present invention provides the following technical solutions.

[0008] The first aspect of the present invention provides a drug-loaded self-healing hydrogel, wherein graphene oxide and a drug are dispersed in a hydrogel matrix material, the hydrogel matrix material is composed of agarose and gelatin, and the mass ratio of the drug, the graphene oxide, the agarose and the gelatin is (0.001-0.1): (0.005-0.05): (0.5-4): (5-40).

[0009] In a preferred embodiment of the present invention, the graphene oxide is a carboxylated graphene oxide dispersion with a flake diameter of <500 nm.

[0010] In a preferred embodiment of the present invention, the drug is selected from one or more of vascular endothelial growth factor, basic fibroblast growth factor, and epidermal growth factor.

[0011] In a preferred embodiment of the present invention, the drug is vascular endothelial growth factor.

[0012] A second aspect of the present invention provides a method for preparing the drug-loaded self-healing hydrogel as described above, the preparation method comprising the following steps: S1: dissolving the drug in PBS buffer to obtain a drug solution; Heat and dissolve agarose and gelatin in water to obtain agarose solution and gelatin solution respectively; S2: mixing the obtained agarose solution and gelatin solution, and then adding graphene oxide and drug solution in sequence and mixing them evenly to obtain a hydrogel precursor solution; S3: The obtained hydrogel precursor solution is placed in a mold and cooled to form a finished drug-loaded self-healing hydrogel.

[0013] In a preferred embodiment of the present invention, in step S1, the heating and dissolving is selected from water bath heating, oil bath heating or thermostat heating; the temperature of the heating and dissolving is 50-70°C.

[0014] In a preferred embodiment of the present invention, in step S1, The mass volume ratio concentration of the agarose solution is 0.5-4%; The mass volume ratio concentration of the gelatin solution is 5-40%.

[0015] In a preferred embodiment of the present invention, in step S2, the mass volume ratio concentration of graphene oxide in the hydrogel precursor solution is 0.005-0.05%, and the mass volume ratio concentration of the drug is 0.001-0.1%.

[0016] In a preferred embodiment of the present invention, in step S3, the mold comprises a circle with a diameter of 0.5-2 cm and a thickness of 0.5-5 mm.

[0017] The third aspect of the present invention provides a product for promoting skin wound healing, wherein the product comprises the drug-loaded self-repairing hydrogel as described above.

[0018] A fourth aspect of the present invention provides a use of the aforementioned drug-loaded self-repairing hydrogel in the preparation of a medicament for promoting skin wound healing.

[0019] By means of the above technical solution, the present invention has at least the following advantages: The present invention provides a drug-loaded self-healing hydrogel. This composite hydrogel is obtained by dispersing graphene oxide and drugs such as vascular endothelial growth factor, basic fibroblast growth factor, and epidermal growth factor in a mixture of agarose and gelatin as a matrix. This hydrogel exhibits both good biocompatibility and degradability.

[0020] The hydrogel of the present invention has good self-repairing ability. After being damaged, it can increase its temperature under the irradiation of near-infrared light, undergoing a gel-sol phase transition, and then undergo a sol-gel phase transition after cooling to achieve self-repair, thereby ensuring its integrity during application, thereby covering and protecting the wound surface.

[0021] The hydrogel of the present invention can release drugs at the wound surface, promoting cell growth and wound repair. More importantly, the hydrogel can also achieve controlled release of drugs through a reversible gel-sol-gel phase transition caused by near-infrared light irradiation. In addition, the hydrogel has the advantages of easy preparation, safety, simplicity, and shape, making it suitable for wounds of various shapes. Animal experiments have shown that the composite hydrogel has a significant effect on promoting the healing of full-thickness skin wounds in rats. The composite hydrogel dressing of the present invention has good application prospects in skin wound healing.

[0022] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is a schematic diagram of the preparation process of the drug-loaded self-repairing hydrogel of the present invention; Figure 2 The photothermal conversion effect, melting point, and self-healing effect of different hydrogels are shown; among them, a is a statistical diagram of the photothermal conversion effect of different hydrogels, b is a statistical diagram of the melting points of composite hydrogels with different proportions, and c is a physical diagram of the self-healing effect of the hydrogel: i is a newly prepared complete hydrogel, ii is a cut hydrogel, iii is a hydrogel put together after infrared light irradiation, and iv is a hydrogel lifted with tweezers after infrared light irradiation; Figure 3 The drug release effect of the hydrogel of the present invention under near-infrared light irradiation is shown; Figure 4 The figure shows the effect of the hydrogel of the present invention on promoting wound repair in rats; wherein, a is a photo of the actual effect of animal wound repair, b is a schematic diagram of the superposition of simulation images of wounds at different times, and c is a statistical graph of the wound recovery effects of different groups of animals. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0025] Unless otherwise specified, the graphene oxide used in the following examples is a carboxylated graphene oxide dispersion (Article No. 100013, purchased from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.) with a flake diameter of <500 nm.

[0026] Example 1: Preparation of self-repairing hydrogel I doped with graphene oxide and vascular endothelial growth factor (1) Dissolve 1 mg of vascular endothelial growth factor (VEGF-A, abbreviated as VEGF) in 1 mL of PBS to obtain a 1 mg / mL VEGF solution.

[0027] Graphene oxide solution (10 mg / mL) was dispersed in ultrasound for half an hour and set aside.

[0028] Weigh 200 mg of agarose and dissolve it in 10 mL of water heated to 70°C to obtain an agarose solution with a mass volume ratio concentration of 2% (w / v).

[0029] Weigh 2 g of gelatin and dissolve it in 10 mL of water heated to 50°C to obtain a gelatin solution with a mass volume ratio concentration of 20% (w / v).

[0030] (2) 100 μL VEGF, 20 μL graphene oxide solution, 250 μL agarose solution, 250 μL gelatin solution, and 380 μL PBS were mixed to obtain a hydrogel precursor solution. The mass volume ratios of VEGF, graphene oxide, agarose, and gelatin in the obtained hydrogel precursor solution were 0.01%, 0.02%, 0.5%, and 5%, respectively.

[0031] (3) The hydrogel precursor solution was cast while hot into a customized mold with a diameter of 1 cm and a thickness of 3 mm and then cooled to room temperature to obtain a drug-loaded self-healing hydrogel I doped with graphene oxide and vascular endothelial growth factor, referred to as hydrogel I.

[0032] Example 2: Preparation of self-repairing hydrogel II doped with graphene oxide and vascular endothelial growth factor The preparation method of Example 2 is substantially the same as that of Example 1, with the only difference being that the mass of gelatin used in step (1) is 3 g, and the rest is consistent with Example 1, specifically: (1) Dissolve 1 mg of VEGF in 1 mL of PBS to obtain a 1 mg / mL VEGF solution.

[0033] Graphene oxide solution (10 mg / mL) was dispersed in ultrasound for half an hour and set aside.

[0034] Weigh 200 mg of agarose and dissolve it in 10 mL of water heated to 70°C to obtain an agarose solution with a mass volume ratio concentration of 2% (w / v).

[0035] Weigh 3 g of gelatin and dissolve it in 10 mL of water heated to 50°C to obtain a gelatin solution with a mass volume ratio concentration of 30% (w / v).

[0036] (2) 100 μL VEGF, 20 μL graphene oxide solution, 250 μL agarose solution, 250 μL gelatin solution, and 380 μL PBS were mixed to obtain a hydrogel precursor solution. The mass volume ratios of VEGF, graphene oxide, agarose, and gelatin in the obtained hydrogel precursor solution were 0.01%, 0.02%, 0.5%, and 7.5%, respectively.

[0037] (3) The hydrogel precursor solution was cast while hot into a customized mold with a diameter of 1 cm and a thickness of 3 mm and cooled to room temperature to obtain a drug-loaded self-healing hydrogel II doped with graphene oxide and vascular endothelial growth factor, referred to as hydrogel II.

[0038] Example 3: Preparation of self-repairing hydrogel III doped with graphene oxide and vascular endothelial growth factor The preparation method of Example 3 is roughly the same as that of Example 1, with the only difference being that 40 μL of graphene oxide and 360 μL of PBS are used in step (2). The rest is consistent with Example 1, specifically: (1) Dissolve 1 mg of VEGF in 1 mL of PBS to obtain a 1 mg / mL VEGF solution.

[0039] Graphene oxide solution (10 mg / mL) was dispersed in ultrasound for half an hour and set aside.

[0040] Weigh 200 mg of agarose and dissolve it in 10 mL of water heated to 70°C to obtain an agarose solution with a mass volume ratio concentration of 2% (w / v).

[0041] Weigh 2 g of gelatin and dissolve it in 10 mL of water heated to 50°C to obtain a gelatin solution with a mass volume ratio concentration of 20% (w / v).

[0042] (2) 100 μL VEGF, 40 μL graphene oxide solution, 250 μL agarose solution, 250 μL gelatin solution, and 360 μL PBS were mixed to obtain a hydrogel precursor solution. The mass volume ratios of VEGF, graphene oxide, agarose, and gelatin in the obtained hydrogel precursor solution were 0.01%, 0.04%, 0.5%, and 5%, respectively.

[0043] (3) The hydrogel precursor solution was cast while hot into a customized mold with a diameter of 1 cm and a thickness of 3 mm and cooled to room temperature to obtain a drug-loaded self-healing hydrogel III doped with graphene oxide and vascular endothelial growth factor, referred to as hydrogel III.

[0044] Example 4: Preparation of self-repairing hydrogel IV doped with graphene oxide and vascular endothelial growth factor The preparation method of Example 4 is roughly the same as that of Example 1, with the only difference being that 5 μL of graphene oxide and 395 μL of PBS are used in step (2). The rest is consistent with Example 1, specifically: (1) Dissolve 1 mg of VEGF in 1 mL of PBS to obtain a 1 mg / mL VEGF solution.

[0045] Graphene oxide solution (10 mg / mL) was dispersed in ultrasound for half an hour and set aside.

[0046] Weigh 200 mg of agarose and dissolve it in 10 mL of water heated to 70°C to obtain an agarose solution with a mass volume ratio concentration of 2% (w / v).

[0047] Weigh 2 g of gelatin and dissolve it in 10 mL of water heated to 50°C to obtain a gelatin solution with a mass volume ratio concentration of 20% (w / v).

[0048] (2) Mix 100 μL of VEGF, 5 μL of graphene oxide solution, 250 μL of agarose solution, 250 μL of gelatin solution, and 395 μL of PBS to obtain a hydrogel precursor solution. The mass volume ratios of VEGF, graphene oxide, agarose, and gelatin in the obtained hydrogel precursor solution are 0.01%, 0.005%, 0.5%, and 5%, respectively.

[0049] (3) The hydrogel precursor solution was cast while hot into a customized mold with a diameter of 1 cm and a thickness of 3 mm and cooled to room temperature to obtain a drug-loaded self-healing hydrogel IV doped with graphene oxide and vascular endothelial growth factor, referred to as hydrogel IV.

[0050] Example 5: Preparation of self-repairing hydrogel V doped with graphene oxide and vascular endothelial growth factor The preparation method of Example 5 is roughly the same as that of Example 1, with the only difference being that 1 μL of VEGF, 5 μL of graphene oxide, 200 μL of agarose solution, 200 μL of gelatin solution, and 594 μL of PBS are used in step (2). The rest is consistent with Example 1, specifically: (1) Dissolve 1 mg of VEGF in 1 mL of PBS to obtain a 1 mg / mL VEGF solution.

[0051] Graphene oxide solution (10 mg / mL) was dispersed in ultrasound for half an hour and set aside.

[0052] Weigh 200 mg of agarose and dissolve it in 10 mL of water heated to 70°C to obtain an agarose solution with a mass volume ratio concentration of 2% (w / v).

[0053] Weigh 2 g of gelatin and dissolve it in 10 mL of water heated to 50°C to obtain a gelatin solution with a mass volume ratio concentration of 20% (w / v).

[0054] (2) 1 μL VEGF, 5 μL graphene oxide solution, 200 μL agarose solution, 200 μL gelatin solution, and 594 μL PBS were mixed to obtain a hydrogel precursor solution. The mass volume ratios of VEGF, graphene oxide, agarose, and gelatin in the obtained hydrogel precursor solution were 0.001%, 0.05%, 4%, and 40%, respectively.

[0055] (3) The hydrogel precursor solution was cast while hot into a customized mold with a diameter of 1 cm and a thickness of 3 mm and cooled to room temperature to obtain a drug-loaded self-healing hydrogel V doped with graphene oxide and vascular endothelial growth factor, referred to as hydrogel V.

[0056] Comparative Example 1: Preparation of Graphene Oxide-Doped Hydrogel VI The preparation method of Comparative Example 1 is substantially the same as that of Example 1, except that VEGF is not added. The rest is consistent with Example 1, specifically: (1) Disperse graphene oxide solution (10 mg / mL) in an ultrasonic bath for half an hour and set aside.

[0057] Weigh 200 mg of agarose and dissolve it in 10 mL of water heated to 70°C to obtain an agarose solution with a mass volume ratio concentration of 2% (w / v).

[0058] Weigh 2 g of gelatin and dissolve it in 10 mL of water heated to 50°C to obtain a gelatin solution with a mass volume ratio concentration of 20% (w / v).

[0059] (2) Mix 20 μL of graphene oxide solution, 250 μL of agarose solution, 250 μL of gelatin solution, and 480 μL of PBS to obtain a hydrogel precursor solution. The mass volume ratios of graphene oxide, agarose, and gelatin in the obtained hydrogel precursor solution are 0.02%, 0.5%, and 5%, respectively.

[0060] (3) The hydrogel precursor solution was cast while hot into a customized mold with a diameter of 1 cm and a thickness of 3 mm and then cooled to room temperature to obtain graphene oxide-doped drug-loaded self-healing hydrogel VI, referred to as hydrogel VI.

[0061] Comparative Example 2: Preparation of self-repairing hydrogel VII doped with vascular endothelial growth factor The preparation method of Comparative Example 2 is substantially the same as that of Example 1, except that graphene oxide is not added. The rest is consistent with Example 1, specifically: (1) Dissolve 1 mg of VEGF in 1 mL of PBS to obtain a 1 mg / mL VEGF solution.

[0062] Weigh 200 mg of agarose and dissolve it in 10 mL of water heated to 70°C to obtain an agarose solution with a mass volume ratio concentration of 2% (w / v).

[0063] Weigh 2 g of gelatin and dissolve it in 10 mL of water heated to 50°C to obtain a gelatin solution with a mass volume ratio concentration of 20% (w / v).

[0064] (2) Mix 100 μL of VEGF, 250 μL of agarose solution, 250 μL of gelatin solution, and 400 μL of PBS to obtain a hydrogel precursor solution. The mass volume ratios of VEGF, agarose, and gelatin in the obtained hydrogel precursor solution are 0.01%, 0.5%, and 5%, respectively.

[0065] (3) The hydrogel precursor solution was cast while hot into a customized mold with a diameter of 1 cm and a thickness of 3 mm and cooled to room temperature to obtain a drug-loaded self-healing hydrogel VII doped with vascular endothelial growth factor, referred to as hydrogel VII.

[0066] Comparative Example 3: Preparation of self-repairing hydrogel VIII doped with graphene oxide and vascular endothelial growth factor The preparation method of Comparative Example 3 is roughly the same as that of Example 1, with the only difference being that 1 μL of VEGF, 5 μL of graphene oxide, 200 μL of agarose solution, 140 μL of gelatin solution, and 654 μL of PBS are used in step (2). The rest is consistent with Example 1, specifically: (1) Dissolve 1 mg of VEGF in 1 mL of PBS to obtain a 1 mg / mL VEGF solution.

[0067] Graphene oxide solution (10 mg / mL) was dispersed in ultrasound for half an hour and set aside.

[0068] Weigh 200 mg of agarose and dissolve it in 10 mL of water heated to 70°C to obtain an agarose solution with a mass volume ratio concentration of 2% (w / v).

[0069] Weigh 2 g of gelatin and dissolve it in 10 mL of water heated to 50°C to obtain a gelatin solution with a mass volume ratio concentration of 20% (w / v).

[0070] (2) 1 μL VEGF, 5 μL graphene oxide solution, 200 μL agarose solution, 140 μL gelatin solution, and 654 μL PBS were mixed to obtain a hydrogel precursor solution. The mass volume ratios of VEGF, graphene oxide, agarose, and gelatin in the obtained hydrogel precursor solution were 0.001%, 0.05%, 4%, and 28%, respectively.

[0071] (3) The hydrogel precursor solution was cast while hot into a customized mold with a diameter of 1 cm and a thickness of 3 mm and cooled to room temperature to obtain graphene oxide-doped drug-loaded self-healing hydrogel VIII, referred to as hydrogel VIII.

[0072] Comparative Example 4: Preparation of self-repairing hydrogel IX doped with graphene oxide and vascular endothelial growth factor The preparation method of Comparative Example 4 is roughly the same as that of Example 1, with the only difference being that 1 μL of VEGF, 5 μL of graphene oxide, 200 μL of agarose solution, 80 μL of gelatin solution, and 714 μL of PBS are used in step (2). The rest is consistent with Example 1, specifically: (1) Dissolve 1 mg of VEGF in 1 mL of PBS to obtain a 1 mg / mL VEGF solution.

[0073] Graphene oxide solution (10 mg / mL) was dispersed in ultrasound for half an hour and set aside.

[0074] Weigh 200 mg of agarose and dissolve it in 10 mL of water heated to 70°C to obtain an agarose solution with a mass volume ratio concentration of 2% (w / v).

[0075] Weigh 2 g of gelatin and dissolve it in 10 mL of water heated to 50°C to obtain a gelatin solution with a mass volume ratio concentration of 20% (w / v).

[0076] (2) 1 μL VEGF, 5 μL graphene oxide solution, 200 μL agarose solution, 80 μL gelatin solution, and 714 μL PBS were mixed to obtain a hydrogel precursor solution. The mass volume ratios of VEGF, graphene oxide, agarose, and gelatin in the obtained hydrogel precursor solution were 0.001%, 0.05%, 4%, and 16%, respectively.

[0077] (3) The hydrogel precursor solution was cast while hot into a customized mold with a diameter of 1 cm and a thickness of 3 mm and cooled to room temperature to obtain a drug-loaded self-healing hydrogel IX doped with vascular endothelial growth factor, referred to as hydrogel IX.

[0078] Comparative Example 5: Preparation of self-repairing hydrogel X The preparation method of Comparative Example 5 is roughly the same as that of Example 1, with the only difference being that VEGF and graphene oxide were not added, and 500 μL of PBS was used in step (2). The rest was consistent with Example 1, specifically: (1) Weigh 200 mg of agarose and dissolve it in 10 mL of water, heating it to 70°C to obtain a 2% (w / v) agarose solution.

[0079] Weigh 2 g of gelatin and dissolve it in 10 mL of water heated to 50°C to obtain a gelatin solution with a mass volume ratio concentration of 20% (w / v).

[0080] (2) Mix 250 μL agarose solution, 250 μL gelatin solution, and 500 μL PBS to obtain a hydrogel precursor solution. The mass volume ratio of agarose and gelatin in the obtained hydrogel precursor solution is 0.5% and 5%, respectively.

[0081] (3) The hydrogel precursor solution was cast while hot into a customized mold with a diameter of 1 cm and a thickness of 3 mm and cooled to room temperature to obtain a self-healing hydrogel X, referred to as hydrogel X.

[0082] Experiment 1: Testing the photothermal conversion ability, melting point and self-healing ability of hydrogels This experiment investigated the temperature changes of hydrogels containing different concentrations of graphene oxide (Example 1, Example 3, Example 4 and Comparative Example 2) after being irradiated with 3W of near-infrared light (NIR) with a wavelength of 808 nm. The irradiation test was performed using a near-infrared laser with a wavelength of 808 nm (MDLIII-808, Changchun New Industrial Optoelectronics Technology Co., Ltd.). The results are shown in Figure 2. Figure 2 a.

[0083] In addition, this experiment also explored the changes in the melting point of composite hydrogels with different proportions (Example 5, Comparative Example 3 and Comparative Example 4) after irradiation with NIR radiation of 808 nm at a power of 3 W. The results are shown in Figure 2 b.

[0084] In addition, the self-healing ability of the hydrogel was also investigated in this experiment. The hydrogel of Example 1 was cut in half and reassembled. After irradiation with NIR light of 808 nm at a power of 3 W for 2 min, the changes between the two separated hydrogel blocks were observed. The results show that Figure 2 c.

[0085] like Figure 2 As shown in Figure 1a, the temperature of the hydrogel samples from different examples increased with prolonged NIR irradiation. However, at the same irradiation time, the temperature of the hydrogels containing different graphene oxide concentrations increased to varying degrees. The higher the graphene oxide concentration, the faster the temperature increase. The temperatures of the hydrogels stabilized at 50°C, 38°C, 33°C, and 26°C, respectively, after a 2-minute irradiation time. These results demonstrate that the photothermal conversion capabilities of hydrogels containing different graphene oxide concentrations differ significantly, with higher concentrations resulting in stronger photothermal conversion capabilities.

[0086] like Figure 2 As shown in Figure b, the melting points of the hydrogel samples of different embodiments all increase as the ratio of gelatin to agarose decreases. The above results show that the melting points of composite hydrogels with different ratios are significantly different, and the lower the ratio of gelatin to agarose, the higher the melting point.

[0087] like Figure 2As shown in Figure c, the hydrogel was cut in half and then reassembled. After 2 minutes of NIR irradiation, the two separated hydrogel blocks could be reconnected. The above results show that the hydrogel of the present invention has a high self-healing ability.

[0088] Experiment 2: Drug release ability test of hydrogel This experiment investigated the drug release ability of the hydrogel. The specific steps were as follows: Fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA) was used as a model drug in place of VEGF and hydrogels were prepared according to the method described in Example 1. 50 μL of the resulting hydrogel was placed in a 2 mL centrifuge tube and 1 mL of PBS solution was added. Two aliquots were prepared simultaneously, serving as experimental and control groups, and each group was treated as follows: Experimental group: irradiated with 808 nm NIR light at a power of 3 W for 2 min each time to induce photothermal release of the drug. After each irradiation, 200 μL of the solution in the tube was collected and an equal volume of fresh PBS was added to make up to 50 μL. Control group: No NIR irradiation treatment was performed, but at the same irradiation time as the experimental group, 200 μL of the solution in the tube was collected and an equal volume of fresh PBS was added to make up to 50 μL.

[0089] The fluorescence intensity of the experimental group solution and the control group solution collected after different irradiation times was read by a multifunctional microplate reader. Figure 3 .

[0090] like Figure 3 As shown in the figure, the cumulative drug release in the experimental group increased with the increase in the number of NIR irradiation cycles. After the 7th irradiation, the cumulative release exceeded 12%, while the cumulative release in the control group was less than 6%. These results indicate that the hydrogel containing graphene oxide has a strong photothermal conversion ability.

[0091] Experiment 3: Repair effects of different hydrogels on rat wounds In this study, we investigated the effects of different hydrogels on full-thickness skin wound healing in rats. A full-thickness skin defect model was used to evaluate the effects of different hydrogel treatments on skin wound healing. The specific methods were as follows: First, a rat full-thickness skin defect model was constructed: 12 healthy SD rats weighing 200-250 g were selected, the backs of the rats were shaved, disinfected with iodine vapor, and full-thickness skin defect wounds with a diameter of 1 cm were made symmetrically on both sides of the spine using sterile surgical scissors.

[0092] The constructed model rats were then randomly divided into 4 groups: a control group, a hydrogel X group of comparative example 5, a hydrogel I group of example 1, and a hydrogel I+NIR group of example 1, with 3 rats in each group. The rats in each group were treated as follows: Control group (Ctrl): without any other treatment.

[0093] Hydrogel X group (GA) of Comparative Example 5: The hydrogel X of Comparative Example 5 was covered on the skin defect area of ​​the rat; Hydrogel I group (GA@VEGF) of Example 1: The hydrogel I of Example 1 was covered on the skin defect area of ​​the rat; Hydrogel I + NIR group (GA@VEGF + NIR) from Example 1: The skin defect area of ​​the rat was covered with hydrogel I from Example 1 and irradiated with a near-infrared laser of 808 nm wavelength and 3 W power for 5 min every 12 h. The model rats in each group were treated according to the above grouping. The wound healing status of each group was observed and photographed regularly every day (standardized photos were taken with a ruler). The wound area of ​​each group of rats was calculated and statistically analyzed. The results are shown in Figure 4 .

[0094] like Figure 4 As shown in the figure, as time goes by, the skin wound area of ​​rats in each group tends to decrease. Among them, on the 9th day, the wound defect area ratio of rats in the control group and comparative example 5 group was the largest (more than 25%), indicating that their healing rate was the lowest, and a large scab was visible on the wound surface. Compared with the control group (40%), the hydrogel I+NIR group of Example 1 can effectively promote the reduction of the wound surface (10%). This result shows that the hydrogel of the present invention can effectively promote the repair of the wound surface.

[0095] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with this profession can make slight changes or modifications to equivalent embodiments of the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A drug-loaded self-repairing hydrogel, characterized in that: The hydrogel is prepared by dispersing graphene oxide and a drug in a hydrogel matrix material. The hydrogel matrix material comprises agarose and gelatin. The mass ratio of the drug, the graphene oxide, the agarose and the gelatin is (0.001-0.1):(0.005-0.05):(0.5-4):(5-40).

2. The drug-loaded self-repairing hydrogel according to claim 1, characterized in that: The graphene oxide is a carboxylated graphene oxide dispersion with a sheet diameter of less than 500 nm.

3. The drug-loaded self-repairing hydrogel according to claim 1, characterized in that: The drug is selected from one or more of vascular endothelial growth factor, basic fibroblast growth factor, and epidermal growth factor.

4. The method for preparing the drug-loaded self-repairing hydrogel according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: S1: dissolving the drug in PBS buffer to obtain a drug solution; Heat and dissolve agarose and gelatin in water to obtain agarose solution and gelatin solution respectively; S2: mixing the obtained agarose solution and gelatin solution, and then adding graphene oxide and drug solution in sequence and mixing them evenly to obtain a hydrogel precursor solution; S3: The obtained hydrogel precursor solution is placed in a mold and cooled to form a finished drug-loaded self-healing hydrogel.

5. The preparation method according to claim 4, characterized in that In step S1, the heating and dissolving is selected from water bath heating, oil bath heating or constant temperature box heating; the temperature of the heating and dissolving is 50-70°C.

6. The preparation method according to claim 4, characterized in that In step S1, The mass volume ratio concentration of the agarose solution is 0.5-4%; The mass volume ratio concentration of the gelatin solution is 5-40%.

7. The preparation method according to claim 4, characterized in that In step S2, the mass volume ratio concentration of graphene oxide in the hydrogel precursor solution is 0.005-0.05%, and the mass volume ratio concentration of the drug is 0.001-0.1%.

8. The preparation method according to claim 4, characterized in that In step S3, the mold comprises a circle with a diameter of 0.5-2 cm and a thickness of 0.5-5 mm.

9. A product for promoting skin wound healing, characterized in that: The product comprises the drug-loaded self-healing hydrogel according to any one of claims 1 to 3.

10. Use of the drug-loaded self-repairing hydrogel according to any one of claims 1 to 3 in the preparation of a medicament for promoting skin wound healing.

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